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Advances in Cell-Based Delivery of Oncolytic Viruses as Therapy for Lung Cancer

February 2024

February 2024
32(1):200788

DOI:10.1016/j.omton.2024.200788

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CC BY-NC-ND 4.0

Authors:

Elahe Nikpayam

Albany Medical College

Moloud Molood Farrokhi

Albany Medical College

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Lung cancer’s intractability is enhanced by its frequent resistance to (chemo)therapy and often high relapse rates that make it the leading cause of cancer death worldwide. Improvement of therapy efficacy is a crucial issue that might lead to a significant advance in the treatment of lung cancer. Oncolytic viruses are desirable combination partners in the developing field of cancer immunotherapy due to their direct cytotoxic effects and ability to elicit an immune response. Systemic oncolytic virus administration through intravenous injection should ideally lead to the highest efficacy in oncolytic activity. However, this is often hampered by the prevalence of host-specific, anti-viral immune responses. One way to achieve more efficient systemic oncolytic virus delivery is through better protection against neutralization by several components of the host immune system. Carrier cells, which can even have innate tumor tropism, have shown their appropriateness as effective vehicles for systemic oncolytic virus infection through circumventing restrictive features of the immune system and can warrant oncolytic virus delivery to tumors. In this overview, we summarize promising results from studies in which carrier cells have shown their usefulness for improved systemic oncolytic virus delivery and better oncolytic virus therapy against lung cancer.

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Review

Advances in cell-based delivery of oncolytic

viruses as therapy for lung cancer

Giti Esmail Nia,

1,2

Elahe Nikpayam,

Molood Farrokhi,

Azam Bolhassani,

and Ralph Meuwissen

2,6

Faculty of Allied Medicine, Cellular and Molecular Research Centre, Iran University of Medical Science, Tehran, Iran;

Department of Basic Oncology, Health Institute of

Ege University, Izmir, Turkey;

Department of Regenerative and Cancer Biology, Albany Medical College, Albany, NY, USA;

Bioscience Department, University of Skövde,

Skövde, Sweden;

Department of Hepatitis and AIDS, Pasteur Institute of Iran, Tehran, Iran;

Ege University Translational Pulmonary Research Center (EgeSAM), Ege

University, Izmir, Turkey

Lung cancer’s intractability is enhanced by its frequent resis-

tance to (chemo)therapy and often high relapse rates that

make it the leading cause of cancer death worldwide. Improve-

ment of therapy efﬁcacy is a crucial issue that might lead to a

signiﬁcant advance in the treatment of lung cancer. Oncolytic

viruses are desirable combination partners in the developing

ﬁeld of cancer immunotherapy due to their direct cytotoxic ef-

fects and ability to elicit an immune response. Systemic onco-

lytic virus administration through intravenous injection

should ideally lead to the highest efﬁcacy in oncolytic activity.

However, this is often hampered by the prevalence of host-spe-

ciﬁc, anti-viral immune responses. One way to achieve more

efﬁcient systemic oncolytic virus delivery is through better pro-

tection against neutralization by several components of the

host immune system. Carrier cells, which can even have innate

tumor tropism, have shown their appropriateness as effective

vehicles for systemic oncolytic virus infection through circum-

venting restrictive features of the immune system and can war-

rant oncolytic virus delivery to tumors. In this overview, we

summarize promising results from studies in which carrier

cells have shown their usefulness for improved systemic onco-

lytic virus delivery and better oncolytic virus therapy against

lung cancer.

INTRODUCTION

Designing therapeutic agents with a high therapeutic index (i.e., efﬁ-

cacy against malignant cells) and minimal or no toxicity to normal

cells is the main current objective for the development of novel ther-

apies against cancer. Future therapeutic approaches must be more

focused and targeted, enabling the delivery of efﬁcient medication

dosages to every tumor cell.

Despite undeniable advancements in

cancer treatment, certain cancers resist effective treatment directly

or through therapy-induced remission. Although drastically better re-

sults may not be possible just now, incremental improvements are

predicted with innovative or enhanced therapies using immuno-

therapy, cell-based medicines, oncolytic virotherapy, and hybrid tech-

niques thereof.

Lung tumors are among the most recalcitrant solid

cancers and, although the last decade has seen a steady development

of immunotherapeutic approaches against lung cancer such as im-

mune checkpoint inhibitors (ICIs) becoming ﬁrst-line standard ther-

apies alone or in combination with long-established chemo- and ra-

diotherapies,

clinical course and prognosis of especially advanced

lung cancer remains rather poor (Table 1). The need for new or better

therapies for lung cancer is urgent and one way to alleviate this neces-

sity could be the application of oncolytic virotherapy.

Intriguingly, the ﬁrst clinical observations of occasional viral infec-

tions that lead to partial and sometimes complete tumor regression

in cancer patients date back more than a hundred years.

These

initial observations were then pursued by more speciﬁed clinical

and preclinical experiments with various well-deﬁned viral strains.

Although results clearly showed the potential of virotherapy, since a

distinct class of now-called oncolytic viruses (OVs) did infect and

lyse cancer cells much more efﬁciently than healthy tissues.

But

there the problem arose. Most early oncolytic virotherapy made use

of wild-type virus strains with high titers that could cause viremia re-

sulting in severe infections and after affecting the vital organs, some-

times ended in lethality through organ failure or sepsis.

13,14

However,

in those early days, not only lethal virulence posed a major problem

but especially the poor understanding of viral tropism for tumor cells

did seriously hamper the clinical efﬁcacy of oncolytic virotherapy.

Only after the onset of knowledge on how to genetically modify vi-

ruses to make them conditionally replicate in speciﬁc host tumor cells

and hence control their toxicity, could these newly engineered OV

strains start to fulﬁll the original expectations of oncolytic virother-

apy. Signiﬁcant clinical results could then be obtained with various

attenuated OV strains

optimized for speciﬁc tumor types. However,

the ultimate challenge for OV therapy is not only the eradication of

locally injected tumor lesions but also all metastases, especially in

advanced cancers. Yet eradication of metastases necessitates systemic

OV infections, although clinical applications thereby have not been

very successful so far.

Even though OVs work well after direct

https://doi.org/10.1016/j.omton.2024.200788.

Correspondence: Azam Bolhassani, Department of Hepatitis and AIDS, Pasteur

Institute of Iran, Tehran, Iran.

E-mail: a_bolhasani@pasteur.ac.ir

Correspondence: Ralph Meuwissen, Ege University Translational Respiratory

Research Center (EgeSAM), Ege University Campus, 35100 Bornova-Izmir,

Turkey.

E-mail: ralph.meuwissen@ege.edu.tr

Molecular Therapy: Oncology Vol. 32 March 2024 ª2024 The Author(s). 1

This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Table 1. Treatment modality for different stages of lung cancer

Modality Process Stage of disease Reference

Non-small cell lung cancer

Surgery

Patients with entirely resectable tumors and in a good

position for resection should consider surgery. When

the cancer is small enough to ensure that resection will

be possible, there has been little or no dissemination to

nearby lymph nodes, and the patient and other tumor

variables are favorable, surgical resection is advised.

Thoracotomy surgery is the most popular type of

surgery. The less-invasive surgery, a limited anterior

thoracotomy, requires a small opening through the

front of the chest. On the other hand, lung cancer

patients frequently undergo a lobectomy.

Segmentectomy or wedge resection may be an option

for individuals with exceedingly small, early-stage lung

tumors or those who cannot tolerate having a lobe

removed because of compromised lung function.

Surgery is the preferred and most effective treatment

for stage I and II diseases. Up to 60% of patients with

stage I illness survive for 5 years. Although surgery is

still the preferred treatment option, 5-year survival

rates for stage II tumors are typically 30%. Resection

may be viable for some stage III tumors; this should be

determined individually. Regrettably, many of these

patients experience recurrence despite resection. Due

to its variability, it is challenging to specify speciﬁc

therapy choices for cancer in stage III. Since the

survival beneﬁts of surgery have not been established,

it is not recommended for individuals with stage

IV illness.

Herbst et al.

4–6

;

Alexander et al.

;

Duma et al.

4–6

Radiotherapy

Radiation therapy (RT) is used to treat cancer to

raise the likelihood of curing the disease, improve

local tumor control, and provide palliative care (e.g.,

improve symptoms and quality of life). Brachytherapy

and external beam radiation therapy are RT’s two basic

delivery systems. The therapeutic ratio is determined

by comparing the maximum damage that the

surrounding healthy tissue can withstand to the

total damage that radiation is intended to cause

to the malignant cells.

At any stage, RT can be used as the ﬁrst-line, curative,

adjuvant, or palliative treatment for lung cancer. Even

though they have stage I and stage II disease, patients

judged inoperable typically receive RT (e.g., due to age).

The current "gold standard" therapy for patients with

stage III illness consists of RT and chemotherapy.

Combining chemotherapy and radiotherapy can be

considered a curative therapy for stage IIIB illness.

Herbst et al.

4–6

;

Alexander et al.

;

Duma et al.

4–6

Chemotherapy

These conditions may all be treated

with chemotherapy:

as the primary treatment for those who

are unable to undergo surgery

to relieve the pain of advanced cancer

to reduce the size of a tumor before

surgery or radiation

to kill cancer cells that were not removed

during surgery to lower the risk of recurrence

to relieve advanced cancer pain and as

maintenance therapy in those with advanced

cancer that is responsive to chemotherapy.

According to studies, postoperative adjuvant therapy

improved 5-year survival rates for patients with stage

IB to stage III illness. At the same time, chemotherapy

appeared to harm patients with stage IA disease.

Adjuvant cisplatin-based chemotherapy is the gold

standard of care for some stage I and the majority

of stage II and III patients with completely resected

NSCLC. Since surgery is typically not an option for

patients in the stage IIIB, chemo-radiation is the

only treatment method used. Despite meager

survival rates, chemotherapy is the primary

treatment for people with stage IV illness.

Herbst et al.

4–6

;

Alexander et al.

4,5

Small cell lung cancer

Chemotherapy

Chemotherapy agent mixtures are typically used to

treat SCLC. One drug, topotecan, a topoisomerase I

inhibitor, has been FDA approved for use in SCLC

as a second-line treatment. In addition, the National

Comprehensive Cancer Network has approved

immunotherapy drugs such as nivolumab and

nivolumab plus ipilimumab as a course of treatment for

SCLC patients who have progressed after receiving one

or more prior regimens or who have relapsed

within 6 months of receiving initial therapy.

Both mild and severe SCLC are

mostly treated with chemotherapy.

van Meerbeeck et al.

;

Zugazagoitia and

Paz-Ares

7–9

Yang et al.

7–9

Radiotherapy

Radiation treatment and chemotherapy boost median

survival to about 1.5 years for limited-stage diseases.

Patients with early-stage illness are also advised to have

radiation therapy to the brain. This is administered

when there is no indication that cancer has progressed

to the brain and chest therapy is the only treatment.

Mortality was reduced when radiation

was used with chemotherapy for both

extensive-stage and limited-stage illnesses.

Zugazagoitia et al.

8–10

;

Yang et al.

8–10

;

Wang et al.

8–10

Surgery Most cases of SCLC cannot be treated with surgery.

Surgery, in addition to chemotherapy, may

be an option for patients with stage I SCLC

and no nodal involvement.

Zugazagoitia et al.

8–10

;

Yang et al.

8–10

;

Wang et al.

8–10

2 Molecular Therapy: Oncology Vol. 32 March 2024

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Review

Table 2. Preclinical studies on OV therapy mechanisms in lung cancer

Oncolytic

virus Virus constructs

Applications and

eventual combined

(chemo)therapies Carrier cell type Results Reference

Vaccinia

virus

vvDD-IL2-RG,

vvDD Intratumoral

IL-2 linked with glycosylphosphatidylinositol

anchor (IL2-RG) expression induces an increased

immune response and almost total tumor

clearing in the subcutaneous transplanted

syngeneic LLC model. Increased

CD4+/CD8+ and TNF-ain TME.

Liu

et al.

VV.mIFN-bSystemic and

intratumoral

Drastic 40% tumor reduction in both NSCLC

syngeneic models using TC-1 and LKRM2 cells

as subcutaneous transplant or orthotopic. Albeit

virus replication was substantially low in

LKRM2 compared with TC-1, both models

showed high cytokine induction due to

ectopic IFN-bexpression.

Wang

et al.

vvDD

Systemic, intravenously

with anti-PD1 and

-TIM3 treatment

Urethane-induced endogenous as well as

syngeneic, subcutaneous transplanted NSCLC

models were used. vvDD infection synergized with

blockade of both PD-1 and TIM-3 through the

efﬁcient direct killing of lung cancer tumor cells

and recruiting and activating T cells for indirect

tumor killing, vvDD was shown to induce higher

expression of both PD-1 and TIM-3 in refractory

lung cancer. Therefore, the triple combination

therapy is more effective for refractory lung cancer.

Yang

et al.

vvDD-IL23, derived

from VV-WR strain

modiﬁed for expressing

recombinant IL23

Intratumoral

LLC (Lewis lung cancer) NSCLC cell line was used

as a subcutaneous transplant in the syngeneic

model. Intratumoral infection with IL-23-armed

vaccinia virus can induce potent antitumor effects

through increased tumor cell death. Oncolysis

combined with expression of membrane-bound

IL-23 induces elevated expression of

chemokines and other antitumor factors

that cause increased antitumor immunity.

Chen

et al.

TG4010, a modiﬁed

vaccinia strain Ankara

(MVA), expressing

human mucin1

(MUC1) and IL-2

Systemic, intravenously

with anti-PD1 treatment

Intravenous injection with CT26 (expressing

human MUC1) colon cancer cells induced

extensive tumor growth in the lung. TG4010

application combined with anti-PD1 caused a

better antitumor immune response and tumor

regression compared with a single TG4010

treatment.

Remy-Ziller

et al.

Oncopox-trail, derived from

VV-WR strain, expressing

recombinant TRAIL

Both intravenous and

intratumoral injections

Tumor regression of A549 xenotransplant

and LLC syngeneic models. TRAIL-induced

increase in apoptosis and necrosis.

Hu et al.

GLV-1h68, replication-

competent recombinant

vaccinia virus derived

from the Lister strain

Intravenous injections

and systemic

cyclophosphamide (CPA)

Systemic application of GLV-1h68 and

CPA have synergistic effects against human

lung adenocarcinoma PC14PE6 cell line in

subcutaneous xenograft models.

Hofmann

et al.

WR A34R(IHD-J) TK-Luc+

recombinant virus derived

from WR strain. This VV

recombinant produces high

levels of extracellular

enveloped virus (EEV)

Intravenous

EEV is covered by host-

cell-derived lipid bilayer

with anti-complement

proteins that protect

against immune clearance.

WR A34R(IHD-J) TK-Luc+ injected in two

syngeneic models. Subcutaneous transplanted lung

cancer cell line CMT64 and lung metastases

producing mammary tumor cell line JC. In both

models, systemic infection with WR A34R(IHD-J)

TK-Luc+ induced a signiﬁcantly higher tumor

clearance level as compared with the WR strain.

Kirn

et al.

vvDD Intravenous

Cytokine-induced killer

(CIK) cells expressing

NKG2D receptor.

CIKs loaded with vvDD were injected into

syngeneic lung metastases producing mammary

tumor (cell line JC) model causing almost

complete clearance of primary tumor

as well as lung metastases.

Thorne

et al.

(Continued on next page)

Molecular Therapy: Oncology Vol. 32 March 2024 3

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Review

Table 2. Continued

Oncolytic

virus Virus constructs

Applications and

eventual combined

(chemo)therapies Carrier cell type Results Reference

VVDTKDN1L

Recombinant virus

with TK and N1L

deletion in VVL15 strain

Intratumoral

LLC NSCLC cell line was used as a subcutaneous

transplant in the syngeneic model. Intratumoral

infection with VVDTKDN1L marked tumor

regression with increased intratumoral CD4+

and CD8+T cells and neutrophil accumulation.

TME changed with increased systemic NK cells

and augmented IL-a, IL1-b, and GCSF.

Ahmed

et al.

Recombinant GLV-1h107,

GLV-1h108 GLV-1h109

contains the GLAF-1 gene

under the control of the

VV SE, SEL, and SL promoters,

respectively. All were inserted

at the J2R locus in the

parental virus GLV-1h68.

Intravenous

Intravenous injection of GLV-1h107,

GLV-1h108, and GLV-1h109, in subcutaneous

xenotransplanted A549 cell line tumor, caused

tumor regression. GLAF-1 is a scAb against VEGF.

Upon i.v. infection GLAF-1 is found inside the

tumor and TME, causing a decrease in blood

vessel formation occurs.

Frentzen

et al.

EphA2-TEA-VV, a T cell

engager armed oncolytic VV

(TEA-VV) encoding secretory

bispeciﬁc. T cell engagers

(TEs) that bind both to human

CD3 and a tumor cell surface

antigen EphA2. Derived from

original vvDD, WR strain.

Intravenous

After lung tumors were formed in systemic

(i.v. injected A549 cell line) xenotransplanted

NSCLC model, EphA2-TEA-VV was i.v. injected

with or without unstimulated PBMCs. Strong

tumor clearance and activation of T cells

together with creased IFN-gand IL-2 secretion.

et al.

Myxoma

virus

Oncolytic myxoma

virus (MYXV)

Intraperitoneal and

intratumoral application

of MYXV, single or

combined with a low

dose of cisplatin

Intratumoral delivery of MYXV to the syngeneic

immunocompetent murine SCLC model induces

extensive tumor necrosis with marked host

immune cell inﬁltration. Intratumoral injection

of human SCLC PDX models in NSG mice

background showed severe impairment

of tumor growth

Kellish

et al.

Recombinant MYXV

expressing IL-15 Intravenous Bone marrow-

derived MSCs

i.v. injected B16-F10 melanoma cell line forming

tumor foci in the lung of syngeneic C57BL6 mice,

followed by i.v. injection with MYXV-IL-15 loaded

MSCs. Formation of pulmonary melanoma foci

was largely prevented, resulting in longer

survival. Treated lungs showed high

inﬁltration with NK and CD8+ T cells.

Jazowiecka-

Rakus et al.

Recombinant MYXV

expressing TNF-a

Intravenous, combined

with ICI anti- PD1/PD-L1

and CTLA-4

Autologous peripheral

blood mononuclear

cells (PBMCs)

i.v. injected K7M2-Luc lung metastatic

osteosarcoma cell line in syngeneic BALB/cJ mice,

followed by i.v. injection with MYXV-TNF-loaded

PBMCs. MYXV-loaded PBMCs caused efﬁcient

lung lesion regression and longer survival.

Combined ICIs anti-PD1/PD-L1 and

anti-CTLA-4 synergized well with MYXV-TNF.

Christie

et al.

Recombinant MYXV-

expressing tumor necrosis

factor family member

TNFSF14 (LIGHT)

Retro-orbital intravenous,

combined with ICI

anti-PD1

PBMCs

i.v. injected K7M2-Luc lung metastatic

osteosarcoma cell line in syngeneic BALB/cJ mice,

followed by systemic application of MYXV-

LIGHT-loaded PBMCs. Treatment led to

overall longer survival and tumor regression.

Very efﬁcient LIGHT expression and onset

of innate and adaptive immune responses.

Christie

et al.

Reovirus Reovirus type 3

Dearing strain (T3D) Intravenous

H1299 human NSCLC cell line was used for

the subcutaneous xenotransplanted lung cancer

model. Reovirus i.v. injected caused tumor

regression and induced a decrease in

HIF-1aexpression thereby lowering

VEGFA levels in the tumor.

Hotani

et al.

(Continued on next page)

4 Molecular Therapy: Oncology Vol. 32 March 2024

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Review

Table 2. Continued

Oncolytic

virus Virus constructs

Applications and

eventual combined

(chemo)therapies Carrier cell type Results Reference

Reovirus T3D Intravenous Adipose-derived MSCs

TC1 NSCLC cell line was used for the

subcutaneous syngeneic lung cancer model.

MSCs loaded with reovirus were i.v. injected

causing tumor regression and growth arrest,

followed by an increase of IFN-gsecretion.

Seyed-

Khorrami

et al.

Measles

virus

Attenuated measles

virus (MV) HU-191 strain Intratumoral

Intratumoral injection with MV Hu-191

in a syngeneic model with subcutaneously

transplanted A549 and LLC tumor cell lines

caused clear tumor cell death and regression

with increased T cell inﬁltration of TME.

Zhao

et al.

Attenuated Schwartz

vaccinal strain of measles

virus expressing recombinant

GFP (MV-eGFP)

Intratumoral

MV-eGFP infection of subcutaneous

xenotransplanted human NSCLC cell lines

ADK3, ADK117, ADK153, and A549 caused

high levels of tumor cell death and tumor

regression. MV oncolysis is associated

with in vivo activation of caspase-3.

Boisgerault

et al.

Inﬂuenza

virus

Low pathogenic oncolytic

inﬂuenza virus IAV Intranasal injections

IAV infection of somatic NSCLC in Raf-BxB mice

leads to reversal of immunosuppressed tumor-

associated lung macrophage function to an

M1-like pro-inﬂammatory active phenotype.

Masemann

et al.

Herpes

simplex

virus

AP27i145 HSV-1, recombinant

HSV-1 expressing complement

miRNA145 sequences in 30

UTR of ICP27

In vitro only

The combination of radiotherapy and AP27i145

infection was signiﬁcantly more potent in

killing NSCLC cell lines (A549, H1975,

H460, and H838) than each therapy alone.

Li et al.

R-LM249, recombinant

HSV-1 retargeted to

exclusively infect HER2

expressing cells

Intravenously Fetal membrane

(FM)-derived MSCs

Single i.v. injection with R-LM249-loaded FM-

MSCs efﬁciently prevented metastatic tumor

formation in the lungs of subcutaneous

xenotransplanted human ovarian cancer

cell line SK-OV-3.

Leoni

et al.

Cf33-GFP

Chimeric poxvirus generated

through homologous

recombination among nine

strains/species of poxviruses,

expressing GFP

Intratumoral

injections

Tumor regression in both xenotransplant

and syngeneic NSCLC models. Inﬁltration

of tumors by CD8+ T cells.

Chaurasiya

et al.

Coxsackie

virus

Coxsackievirus B3

(CVB3) strain

Intratumoral,

injections

CVB3 was injected in a subcutaneous

xenotransplant NSCLC (A549 or EBC-1 cells)

model. Tumor regression and clearance with

NK and granulocyte inside tumor and TME.

Tumor cells express calreticulin and secreted

ATP as well as HMGB1.

Miyamoto

et al.

CVB3 strain

Intratumoral injections,

with wild-type or

UV-inactivated CVB3

Single-dose CVB3 injection in subcutaneous

xenotransplanted, KRAS

mut

human NSCLC cell

line (A549, H2030, and H23) tumors. A speciﬁc

increase in tumor cell death and regression

occurred, suggesting that CVB3 is a potent OV for

preferential KRAS-mutant lung adenocarcinoma.

Deng

et al.

microRNA-modiﬁed

CVB3 (miR-CVB3) strain

containing multiple

miR-145/miR-143 sequences

Intraperitoneal

Infection of miR-CVB3 in both NSCLC, KRAS

mut

(cell lines A549, H2030, and H23) and SCLC,

Trp53

mut

/RB

mut

(cell lines H524 and H526) causes

signiﬁcant tumor regression in both lung tumor

types, expanding CVB3 tropism to SCLC,

independent from KRAS status.

Liu

et al.

Bovine

herpes

virus

Bovine herpes virus 1

(BoHV-1) strain

Intratumoral with

trichostatin A treatment

Infection of BoHV-1 in subcutaneous

xenotransplanted A549 cell line tumor caused

tumor regression. HDAC levels are repressed, and

BoHV-1 shows synergy with HDAC inhibitor

trichostatin A.

Qiu

et al.

(Continued on next page)

Molecular Therapy: Oncology Vol. 32 March 2024 5

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Table 2. Continued

Oncolytic

virus Virus constructs

Applications and

eventual combined

(chemo)therapies Carrier cell type Results Reference

Newcastle

disease

virus

Wild-type NDV strain

(NDV/Altai/pigeon/770/201) Intratumoral

NDV infection of A549 human lung tumor

cells in subcutaneous xenotransplant model.

Increased necrotic effect on tumor cells

but not on non-tumor cells and PBMCs.

Yurchenko

et al.

Wild-type FMW

strain (NDV/FMW) Intratumoral

FMW infection in subcutaneous xenotransplanted

tumor cell lines A549 and H460 induced tumor

regression and tumor cell death mainly via

autophagy.

et al.

Wild-type FMW

strain (NDV/FMW)

NDV-FMW triggers caspase-dependent apoptosis

in lung cancer spheroids and promotes autophagic

degradation in lung cancer spheroids by inhibiting

the AKT/mTOR pathway. NDV-FMW injected in

subcutaneous xenotransplanted H460 spheroid

cell clusters induced tumor regression.

et al.

Attenuated NDV-HUJ

strain derived from the

original NDV B1 strain

Intravenous

NDV-HUJ was injected in a syngeneic model

with metastasizing lung adenocarcinoma cell line

3LL-D122 as a subcutaneous and orthotopic lung

transplant. Virus-selective oncolysis is dependent

on apoptosis and is associated with higher levels

of viral transcription, translation, and progeny

virus formation.

Yaacov

et al.

Recombined NDV

strain (NDV-D90) Intratumoral

NDV-D90 maintains tumor-selective replication

properties and induces tumor cell apoptosis.

A549 human lung tumor cells in subcutaneous

xenotransplant model showing impairment

of tumor growth.

Chai

et al.

Adenovirus

H101, generated by both

deleting E1B and E3 in

adenovirus type 5 (Ad5)

Intratumoral

Human lung adenocarcinoma cell line XWLC-05

subcutaneous xenotransplant model. High levels

of cytotoxicity, efﬁcient cell lysis, and G2/M

arrest cause signiﬁcant tumor regression.

Lei

et al.

Ad-apoptin, recombinant

Ad5-expressing apoptin Intratumoral

Ad-apoptin injected in subcutaneous

xenotransplant lung tumor (A549 cells) model

showing impairment of tumor growth, and

increased apoptosis. Ad-apoptin targets AMPK

and inhibits glycolysis, migration, and invasion

of lung cancer cells through the AMPK/mTOR

signaling pathway.

Song

et al.

Ad.hTERT-E1A-TK,

recombinant Ad5

expressing HSV-TK

and hTERT driving

Intratumoral

Ad.hTERT-E1A-TK infection combined with

administration of prodrug gancyclovir (GCV)

resulted in more potent cytotoxicity on A549

cells and synergistically suppressed human

lung cancer A549 tumor growth in the

subcutaneous xenotransplant model.

Zhang

et al.

Complete E1B-deleted

conditionally replicating

Ad (CRAd) Adhz60

Intratumoral and

intrape, with

temozolomide (TMZ)

H441 human lung tumor cell line in

subcutaneous xenotransplant model.

Adhz60 acted synergistically with TMZ

in suppressing tumor growth.

Gomez-

Gutierrez

et al.

OBP-301 (telomelysin) is

an attenuated Ad5 with a

hTERT promoter driving

both E1A and E1B to regulate

viral replication. OBP-301

sensitizes human cancer cells

to ionizing radiation by

inhibiting DNA repair

Intratumoral,

with gemcitabine

OBP-301 and gemcitabine have synergistic

effects causing increased regression of

tumor lesions in subcutaneous xenografts

of human lung cancer cell lines H460,

H322, and H358.

Liu

et al.

(Continued on next page)

6 Molecular Therapy: Oncology Vol. 32 March 2024

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Review

Table 2. Continued

Oncolytic

virus Virus constructs

Applications and

eventual combined

(chemo)therapies Carrier cell type Results Reference

Ad5/3-D24aCTLA4

Expressing Ig2 type

anti-CTLA4 mAb in

E1A-deleted Ad5/3

chimeric virus

Intratumor

Ad5/3-D24aCTLA4, injected in a subcutaneous

xenotransplant lung tumor (A549 cells) model.

Severe tumor regression and inhibition of

Tregs and increased CD8+/Treg ratios;

increased T cell activity.

Dias

et al.

Capsid-modiﬁed,

Ad5-derived virus Intravenous Mesenchymal

stem cells (MSCs)

MSCs loaded with modiﬁed Ad5 homed primarily

to lungs in orthotopic xenotransplanted NSCLC

cell line model. Signiﬁcantly increased tumor

regression. Very efﬁcient systemic delivery

of Ad5 in various organs besides the liver.

Hakkarainen

et al.

Ad-IAI.3b,

derived from Ad5 Intravenous

A549 cells were ﬁrst

infected with Ad-IAI.3b

and then irradiated

Irradiated and with Ad-IAI.3b-loaded A549 tumor

cells into orthotopic xenotransplanted lung

squamous cell carcinoma cell line (KLN205)

model. Accumulation of Ad-IAI.3b in the lung

with strong tumor regression. Increased tumor-

inﬁltrating lymphocytes (TILs) with high

Th1-related cytokine expression.

Saito

et al.

Ad-uPAR-MMP-9,

expressing antisense

RNAs against uPAR

and MMP-9

Intratumoral

and intravenous

Ad-uPAR-MMP-9 was injected into a

subcutaneous xenotransplant lung tumor

(H1299). Severe tumor regression and

impaired angiogenesis. Ad-uPAR-MMP-9 was

i.v. injected into a subcutaneous xenotransplant

metastasizing lung tumor (A549). A strong

decrease in angiogenesis but also metastasizing

capacity is shown by the low number

and size of lung metastases.

Rao

et al.

AdE3-SCCA1 derived

from Ad E3. Here the

squamous cell carcinoma

(SCC) speciﬁc promoter

SCCA1 drives E1A expression

Intratumoral A549 cells infected

with AdE3-SCCA1

A549 tumor cells loaded with AdE3-SCCA1 were

injected into a syngeneic subcutaneous SCC (SCC7

cells) model. Mice were preimmunized against

AdE3 and only the loaded A549 cells induced

complete tumor regression. Co-loading A549

with AdE3-SCCA1 and Ad-mGM-CSF

augmented the anti-tumor effect.

Hamada

et al.

ICO15K-FBiTE, expressing

FBiTE, a bispeciﬁc T cell

engager against FAP.

Fibroblast activation

protein-a(FAP) is highly

overexpressed in cancer-

associated ﬁbroblasts (CAFs)

Intravenous combined

with preactivated T cells

from human PBMCs

ICO15K-FBiTE, injected in subcutaneous

xenotransplant lung tumor (A549 cells) model.

Clearance of tumor lesion and activation and

proliferation of T cells; resulting in CAF

targeting. Increased tumor T cell retention

and accumulation in tumor and TME.

Sostoa

et al.

Freedman

et al.

Recombinant adenovirus

KGHV500, expressing

anti-p21Ras scFv

Intravenous CIK cells

CIKs loaded with KGHV500 were intravenously

injected into an A549 tumor xenotransplant model

leading to signiﬁcantly increased tumor regression.

Note that A549 has high expression of KRAS

V12

and KGHV500 and anti-p21Ras scFv were

observed in tumor tissue but were nearly

undetectable in normal tissues.

Lin

et al.

Recombinant adenovirus

ZD55 harboring tumor

necrosis factor (TNF)-related

apoptosis-inducing ligand

(TRAIL), manganese-

containing superoxide

dismutase (MnSOD),

and TRAIL-isoleucine-

aspartate-threonine-glutamate

(IETD)-MnSOD

Intravenous CIK cells

CIKs loaded with ZD55 were intravenously

injected into an A549 tumor xenotransplant

model inducing a signiﬁcantly higher level of

tumor cell death and lower tumor volumes

as compared with the non-transgene expressing

control ZD55. Tumor tropism of ZD55-loaded

CIKs was very high.

Jiang

et al.

(Continued on next page)

Molecular Therapy: Oncology Vol. 32 March 2024 7

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Review

Table 2. Continued

Oncolytic

virus Virus constructs

Applications and

eventual combined

(chemo)therapies Carrier cell type Results Reference

ICOVIR-15 with E2F

responsive palindromes in

E1A promoter, as CRAd

derived from AdD24-RGD;

replication-incompetent Ad-iC9,

expressing inducible caspase-9

Intravenous

Bone marrow-derived

MSCs loaded with

combined ICOVIR-15

and Ad-iC9

MSC loaded with ICOVIR-15/Ad-iC9 were

systemically applied in a subcutaneous A549

tumor xenotransplant model After 48–72 h, MSCS

could be detected in local tumor tissue resulting

in consistent tumor clearance and longer

survival of treated mice.

Hoyos

et al.

Single ICOVIR-15 Intravenous with

allogeneic PBMCs

Human menstrual

blood-derived MSCs

loaded with ICOV_

IR-15

MSCs loaded with ICOVIR-15, combined

with allogeneic PBMCs, systemically infected

in a subcutaneous A549 cell xenotransplant

model. Efﬁcient clearance of tumor mass and

antitumor efﬁcacy partially mediated by

monocytes and NK cells.

Moreno

et al.

ICOVIR-5, strain

analog to ICOVIR-15 Intraperitoneal Murine bone

marrow-derived MSCs

MSCs loaded with ICOVIR-5 (Celyvir therapy),

i.p. infected in syngeneic murine lung

adenocarcinoma (CMT64 cells) model. Signiﬁcant

tumor clearance occurred, loaded MSCs homing

into the CMT64 tumor followed by an invasion

of the tumor bed by a high number of CD8+

and CD4+ cells.

Rincón

et al.

ICOVIR-5, strain

analog to ICOVIR-15 Intravenous

Murine bone marrow-

derived MSCs, either

syngeneic or allogeneic

MSCs loaded with ICOVIR-5 (Celyvir therapy),

systemically infected in syngeneic murine lung

adenocarcinoma (CMT64 cells) model. Tumor

clearance after Celyvir treatment. Both syngeneic

and allogeneic Celyvir induce systemic activation

of the immune system, similar antitumor effect,

and a higher intratumoral inﬁltration of

leukocytes, as shown by high inﬁltration

of CD45+ cells in the tumor core.

Morales-

Molina

et al.

ICOVIR15-cBiTE, expressing

an epidermal growth factor

receptor (EGFR)-targeting

bispeciﬁc T cell engager (cBiTE)

Intraperitoneal with

allogeneic PBMCs

Human menstrual

blood-derived MSCs

MSCs loaded with ICOVIR15-cBiTE, systemically

infected in subcutaneous (A549) xenotransplanted

human adenocarcinoma model. Enhanced tumor

clearance compared with unarmed IVOVIR-15.

Barlabé

et al.

Vesicular

stomatitis

virus

Recombinant oncolytic vesicular

stomatitis virus (VSV) pseudo-

typed with LCMV-GP expressing

tumor-associated antigens,

termed VSV-GP-TAA

Intravenous with

KISIMA-TAA as a

self-adjuvant cancer

vaccine in combination

with anti-Pd1 antibody

Priming vaccination with KISIMA-TAA

followed by VSV-GP-TAA resulted in strong

tumor regression and even increased with

anti-PD1, in the syngeneic NSCLC model using

TC-1 cell line as subcutaneous transplant.

Das

et al.

Attenuated, recombinant

Av3 strain, expressing GFP Intravenous

Murine CT26 colon

carcinoma and L1210

leukemia cell lines.

Human A549 lung

adenocarcinoma cell line

Tumor cell lines loaded with Av3 were injected in

orthotopic transplanted (CT26 lung tumor cell

line) syngeneic models. Both murine tumor cell

lines delivered high doses of VSV, even when

recipient tumor-bearing mice were pre-

immunized against VSV. The xenogeneic human

A549 cell line showed similar carrier efﬁciency.

Lung tumor carrier cells end up preferentially in

the lung while leukemic carrier cells disperse

systemically. Cell-mediated delivery of VSV can

be achieved using allogeneic or xenogeneic

carrier tumor cell lines, proving that carrier

cells can evade immune responses against OVs.

Power

et al.

Voyager-V1 (VV1) VSV

strain expressing IFN-b

and sodium iodide

symporter (NIS)

Intravenous, combined

with anti- CTLA4 and

PD1 Abs

VV1, combined with anti-CTLA4 and anti-PD-1,

were intravenously injected in syngeneic CMT64

adenocarcinoma cell line models and induced

durable tumor regression, high level of TILs

and efﬁcient CD8 TL response against

CMT64 neo epitopes.

Ram

et al.

(Continued on next page)

8 Molecular Therapy: Oncology Vol. 32 March 2024

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Review

injection into tumors, their systemic application shows a far lower

anti-tumor efﬁcacy. The latter effect is mainly due to OV’s susceptibil-

ity to factors of the innate and adaptive immune systems such as com-

plement proteins, antibodies, and the reticuloendothelial system that

surveys the blood circulation for oncolytic virions. More speciﬁcally,

complement proteins have been found to compromise oncolytic func-

tions of OVs.

Nonetheless, some of the complement protein effects

can be antagonized by intrinsic factors encoded by speciﬁc OVs, such

as glycoprotein C of herpes simplex virus (HSV) and complement con-

trol protein VCP encoded by vaccinia virus (VV).

19,20

In addition, it

became clear that systemic anticancer treatment efﬁcacies of OV plat-

forms derived from measles virus,

vesicular stomatitis virus (VSV),

reovirus,

HSV,

adenovirus,

and parvovirus

are signiﬁcantly

hampered or eliminated by pre-existing or therapy-induced neutral-

izing antibodies. Table 2 presents an overview of several viruses that

have been used in (pre)clinical applications against lung cancer, indi-

cating potential (dis)advantages for the therapeutic use of each

OV type.

On the other hand, improvements in molecular engineering have

made it possible to alter the viral genome to increase its anticancer ac-

tivity by inserting novel transgenes and attenuating their virulence by

removing viral genes associated with pathogenesis.

Since the FDA

recently approved a modiﬁed HSV strain, talimogene laherpaprevec

(T-vec), for the treatment of melanoma, oncolytic virotherapy has

become more accepted.

Patients with intradermal metastatic mela-

noma are administered this OV via intratumoral injections that

initiate anti-tumor immune responses leading to a sustainable clinical

efﬁcacy.

84,85

However, the overall response to intratumoral injections

of primarily visceral illnesses, such as late-stage metastasizing non-

small cell lung cancer (NSCLC), is quite low. Visceral malignancies

can be targeted through systemic OV application, but efﬁcient tumor

cell infection might still be impaired due to the lowering of the viral

load by complement and antiviral antibodies.

The possibility of

more signiﬁcant systemic toxicity may be another drawback to intra-

venous OV application.

Several different methods have been tried to

reduce these risks, such as immunological suppression to inhibit the

neutralizing antibody response or alterations to the virus to prevent

detection using concealed common antigens. Speciﬁcally, for VV,

several methods have been described to suppress antibody-mediated

viral clearance. In one study, the extracellular enveloped virus (EEV)

form of VV was covered by a lipid layer with anti-complement pro-

teins after which systemic use of these modiﬁed EEVs generated a far

lower viral clearance.

In a more recent study from Nakatake et al.,

partial deletion of vaccinia surface glycoprotein B5R generated an

EEV form with a higher antibody-dependent neutralization resistance

than the wild-type EEV. The latter mechanism can be used by VV via

its EEV form, consisting of a normal virion covered with a host cell-

derived outer membrane that enables its spread via circulation while

evading host immune mechanisms.

Even so, immune suppression

might turn out to be a two-edged sword since it might as well nega-

tively affect the OV-induced antitumor immune response.

Apart from all these methods, there is a need for alternative tech-

niques to facilitate shielded OV delivery

91,92

since systemic infection

with naked virions has so far been shown to insufﬁciently escape the

above-described humoral immunity factors. One proposed delivery

method to solve OV’s issues with both blood clearance and tumor

penetration is based on the use of a patient’s own cells as a "Trojan

horse"-like delivery vehicle for OVs. Here, the patient’s own “carrier”

cells are ﬁrst infected ex vivo, followed by systemic injection of these

OV-carrier cells, which then are ideally transported into the tumor

beds causing efﬁcient tumor infection and lysis. Considering that cells

are the viruses’natural hosts, seeing them as stealth OV carriers is

indeed very tempting. Even more so, the immune system typically ig-

nores OV carriers until antigen production begins in the latter stages

of infection. However, note that not every cell type can harbor or

replicate a speciﬁc virus as efﬁciently as to serve as an ideal carrier.

Research using intravenous administration of naked reovirus to pa-

tients revealed that all viral particles found in the blood were cell asso-

ciated, indicating that some viruses may naturally convey themselves

via cell carriers (Table 3). So, cells can act as OV carriers.

One study

intriguingly demonstrated that human monocytes loaded with pre-

formed reovirus-antibody complexes (neutralizing the reovirus)

could ultimately deliver replication-competent reovirus to melanoma

cells in vitro.

Here we present an overview of OV therapy used

against lung cancer and how to improve its efﬁcacy using carrier cells

for the systemic delivery of OVs. We discuss the use, advances, and

future promises that such improved techniques hold for therapy

against lung cancer, especially when combined with established (im-

mune) therapeutic approaches.

Lung cancer

According to GLOBOCAN 2020, lung cancer has worldwide an ex-

pected 2.2 million new cases (11.4%) and is the major cause of cancer

mortality, with an estimated 1.8 million deaths (18%).

105

There are

Table 2. Continued

Oncolytic

virus Virus constructs

Applications and

eventual combined

(chemo)therapies Carrier cell type Results Reference

VSV-IFN-b, recombinant

VSV expressing interferon-bIntravenous

Blood outgrowth

endothelial cells

(BOECs)

Syngeneic lung metastatic LM2 mammary tumor

model was intravenously injected with VSV-IFN-b

loaded BOECs causing a major regression of lung

metastases. Similar i.v. application in an A549

xenotransplantation model led to severely

increased antitumor activity and survival.

Patel

et al.

Molecular Therapy: Oncology Vol. 32 March 2024 9

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Review

Table 3. Clinical applications of systemic OV therapy for lung cancer

Oncolytic

virus Virus construct

Combination

therapy

Phase of

development Method and results

Clinical trials

identiﬁer and references

Adeno

virus Ad-HSVtk

Stereotactic body

radiotherapy and

pembrolizumab

II window of

opportunity,

Metastatic non-small cell lung cancer (NSCLC). In

situ, intratumoral, OV therapy consists of

adenovirus-mediated expression of herpes simplex

virus thymidine kinase (ADV/HSVtk) plus

valacyclovir therapy. Initial 28.5% complete or

partial response. The study is ongoing.

NCT03004183

Ad-HSVtk

Stereotactic body

radiotherapy and

nivolumab

II window of

opportunity

terminated

Intratumoral injection with Ad-HSVtk in metastatic

squamous and non-squamous NSCLC. No results,

the study is terminated.

NCT02831933

Adapted Ad-HSVtk

(CAN-2409) Pembrolizumab II

Intratumoral injection of CAN-2409 in patients with

stage III/IV, refractory NSCLC. The study is

ongoing.

NCT04495153

ColoAd1, chimeric

adenovirus strain

(enadenotucirev)

i.v. infusion with enadenotucirev to assess delivery in

patients with NSCLC. A study completed:

enadenotucirev was delivered in most tumor samples

following i.v. infusion, with almost no activity in

normal tissue. Virus delivery coincided with high

local CD8+ cell inﬁltration in 80% of tested tumor

samples, suggesting a potential enadenotucirev-

driven immune response. Enadenotucirev delivery

was well tolerated, with no serious adverse events.

NCT02053220

Garcia-Carbonero

et al.

Ad-MAGEA3, adenovirus

vaccine expressing MAGE-A3 Pembrolizumab I/II IO-resistant stage IV NSCLC. Study is ongoing. NCT02879760

MEM-288, adenovirus

expressing recombinant

CD40L and human IFN-b

Intratumoral injection in stage III/IV NSCLC

patients. Initial determination of MTD and

recommended phase II dose for the planned

combination of MEM-288 with an immune

checkpoint inhibitor. The study is ongoing.

NCT05076760

Combination of oncolytic

Onc.Ad5D24 and helper

-dependent HDD28E4

PD-L1, expressing

PD-L1 antibody

Onc.Ad5D24 and HDD28E4

PD-L1 (CAd-VECPDL1) in

combination with

HER2-speciﬁc CAR

T cell therapy

Patients with HER2-positive (including NSCLC)

solid tumors. Intratumoral injection with CAdVEC

followed by HER2-CAR T cell application.

Determining MTD and inﬂuence of tumor

microenvironment changes on CAR T therapy

efﬁcacy. The study is ongoing.

NCT03740256

Tanoue et al.

Recombinant adenovirus

expressing human IFN-l,

Onc.Ad.L-IFN

Onc.Ad.L-IFN (YSCH-01)

single use I

Intratumoral injection with YSCH-01 in solid

tumors (including NSCLC) determining MTD and

safety. Study ongoing.

NCT05180851

ICOVIR-5 (CELYVIR) MSCs loaded

with ICOVIR-5 II

Trial to determine the toxicity and clinical outcome

of infusion of autologous MSCs infected with the

oncolytic adenovirus ICOVIR5 (CELYVIR)

systemically applied in children with refractory or

recurrent metastatic solid tumors.

Results not posted. Ended prematurely.

EudraCT no.

2008-000364-16

CELYVIR MSCs loaded

with ICOVIR-5 I/II

Evaluation of the safety and clinical response of

weekly (n = 6) infusions of CELYVIR in children and

adults with metastatic and refractory solid tumors.

Well-tolerated treatment, with only mild toxicity,

with the potential to achieve clinical responses in

patients with advanced tumors. The study is

completed.

NCT01844661

Ruano et al.

CELYVIR MSCs loaded

with ICOVIR-5 I/II

Studies the feasibility of the combination of

AloCELYVIR with chemotherapy and radiotherapy

for the treatment of children and adolescents with

relapsed or refractory extracranial solid tumors. The

study is ongoing, and results are not posted.

EudraCT no.

2019-001154-26

Measles

virus MV-NIS Atezolizumab I

Intratumoral injection with measles virus, expressing

sodium iodide symporter (MV-NIS) for recurrent

and metastatic NSCLC. Study is ongoing.

NCT02919449

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10 Molecular Therapy: Oncology Vol. 32 March 2024

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Review

Table 3. Continued

Oncolytic

virus Virus construct

Combination

therapy

Phase of

development Method and results

Clinical trials

identiﬁer and references

Maraba

virus

MG1 strain expressing

tumor-associated antigen

MAGE-A3 (MG1-MAGEA3)

MG1-MAGEA3

with vaccine

Ad-MAGEA3

I/II

Initial vaccination with Ad-MAGEA3 is followed by

intravenous injections with MG1-MAGEA3 in

refractory NSCLC after complete platinum-based

chemotherapy and PD-1 or PD-L1 antibody-

targeted therapy. Study is ongoing.

NCT02879760

Coxsackie

virus

Coxsackie A21

strain (CVA21)

CVA21 with

pembrolizumab IIntravenous injection in refractory NSCLC patients.

Study is ongoing. NCT02043665

Vaccinia

virus

Recombinant vaccinia

virus VV-GL-ONC1,

derived from Lister strain.

Expressing luciferase

and b-galactosidase

GLV-1h68 or

GL-ONC1 alone IIntra-pleural administration in NSCLC patients with

malignant pleural effusion. The study is ongoing. NCT01766739

GL-ONC1 GL-ONC1 alone I

Systemic application for NSCLC patients. Dose

safety proﬁle and viral delivery were monitored.

Study is ongoing.

NCT00794131

TG4010 (Mva-Muc1-Il2),

a modiﬁed vaccinia strain

Ankara (Mva), expressing

human mucin1 (MUC1)

and IL-2

TG4010 alone or

after combined

vinorelbine/cisplatin

i.v. infusion with TG4010 in stage IIIB or IV NSCLC

patients. A total of 65 patients were treated: 35.1% of

TG4010 (combined) showed PR and 14.1% of

TG4010 (alone) had CR. The OS for TG4010

(combined) was 12.7 months and for TG4010

(alone) 14.9 months. The combination of TG4010

with chemotherapy was well-tolerated and gave

promising results.

Ramlau et al.

TG4010 TG4010 in combination

with ﬁrst-line chemotherapy IIB/III

Intravenous infusion with TG4010 in stage IV

NSCLC patients. A total of 222 patients were treated:

median PFS in TG4010 patients was 5.9 months and

in the placebo group 5.1 months. No adverse

treatment effects were noted. Overall TG4010

combined with chemotherapy improves PFS vs.

single chemotherapy treatment. The study is

completed.

NCT01383148

Quoix et al.

BT-001, modiﬁed vaccinia

strain expressing anti-

CTLA4 and human GM-CSF

BT-001 and

pembroluzimab I/II

Intratumoral injection BT-001 in patients with

metastatic and advanced NSCLC. The study is

ongoing.

NCT04725331

JX-594, modiﬁed vaccinia

virus expressing human

GM-CSF

Intravenous infusion of JX-594 in advanced NSCLC

patients. The study is ongoing. MTD was determined

but virus delivery efﬁcacy was moderate. Good

safety/toxicity proﬁle.

NCT00625456

Breitbach et al.

100

Vesicular

stomatitis

virus

Voyager-V1 (VV1) VSV

strain expressing IFN-b

and NIS

VV1 and

pembroluzimab II

Intravenous injection with VV1 in refractory NSCLC

or pulmonary neuroendocrine cancer (NEC,

including SCLC) patients after initial treatment with

pembroluzimab.

NCT03647163

Reovirus reolysin: human reovirus

type 3- Dearing strain

reolysin combined

with docetaxel and

pemetrexed

Systemic intravenous injection of reolysin in patients

with recurrent or metastatic NSCLC; 166 patients

were enrolled (14 to the safety run-in). The study is

completed: reolysin did not improve the progress-

free survival (PFS vs. single agent chemotherapy

(median PFS 3.0 months, 95% conﬁdence interval

[CI], 2.6–4.1) vs. 2.8 months (95% CI, 2.5–4.0),

hazard ratio (HR) 0.90 (95% CI, 0.65–1.25), p =

0.53). Neither KRAS nor EGFR mutation was

associated with improved PFS, but STK11 mutations

did appear to have an association with improved PFS

(HR 0.29 [0.12–0.67); as did PIK3CA mutation (HR

0.45 [0.22–0.93]). The combination was tolerable,

although associated with increased rates of

neutropenic fever.

NCT01708993

Bradbury et al.

101

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Molecular Therapy: Oncology Vol. 32 March 2024 11

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Review

two main types of lung cancer: small cell lung cancer (SCLC) and

NSCLC, whereby NSCLC makes up over 85% of cases overall, while

SCLC makes up just about 15%. Based on histological characteristics,

NSCLC is further categorized into lung adenocarcinomas (40%),

squamous cell carcinoma (25%–30%), giant cell carcinoma (10%–

15%), and some not otherwise speciﬁed (15%–20%)

106–108

(Figure 1).

Lung cancer is typically asymptomatic in its early stages, and this is

one of the main reasons why most lung cancer patients are diagnosed

relatively late with stage III or stage IV. Moreover, lung cancer pa-

tients are often diagnosed between the ages of 60 and 80, with the

most frequent occurrence between 65 and 75. Of these individuals,

50%–70% have locally progressed or fully metastasized cancer. The

International Association for the Study of Lung Cancer claims that

the 5-year survival rates in NSCLC stages IIIA, IIIB, IIIC, and IV,

were 36%, 26%, 13%, and 6%, respectively. The older population is

ineligible for intensive treatment because of the age-related functional

deterioration of several organs, which poses a problem in treating

lung cancer.

109,110

Lung cancer therapy relies on the tumor stage at

the time of diagnosis (Table 1, types of treatment for various stages).

Surgical resection is the recommended course of therapy for individ-

uals with NSCLC in stages I and II. For stage II malignancies, plat-

inum-based adjuvant treatment is advised after complete resection.

Patients whose tumors cannot be surgically removed are adminis-

tered radiation and chemotherapy with a curative goal (stage IIIB).

Palliative treatments and radio-chemotherapy are provided to pa-

tients who are in advanced stages (stage IV).

108,111–113

Patients with

SCLC have a signiﬁcantly lower life expectancy compared with those

with NSCLC.

114

Typically, SCLC has an early onset of metastasis

whereby early, limited lesions already have similar histopathological

features as extensive lesions. Therefore, only lesion size and presence

of metastasis determine if SCLC is of limited or extended stage (Nich-

olson, 2021). For both SCLC stages, the standard of care is radiation

with platinum-based chemotherapy. Although SCLC initially re-

sponds well to radio-chemotherapy, almost all tumors eventually

relapse leading to high mortality rates. Recently, some advances in

anti-SCLC treatment have been achieved using immune checkpoint

Table 3. Continued

Oncolytic

virus Virus construct

Combination

therapy

Phase of

development Method and results

Clinical trials

identiﬁer and references

reolysin

reolysin combined

with paclitaxel and

carboplatin

Systemic intravenous injection of reolysin in patients

with recurrent or metastatic NSCLC. Out of 37

patients enrolled, 20 patients had detected K-Ras

mutations, 3 patients had EGFR mutations, 10

patients had EGFR ampliﬁcations alone, and 4

patients had BRAF V600E mutations. The study is

completed: median PFS was 4 months (95% CI, 2.9–

6.1), median OS was 13.1 months (95% CI, 9.2–21.6),

and 1-year OS rate was 57% (95% CI, 39%–72%).

NCT00861627

Gong et al.

102

Villalona-Carrero et al.

103

reolysin

reolysin combined

with paclitaxel and

carboplatin

Systemic intravenous injection of reolysin in patients

with recurrent or metastatic SCC. Out of 25 patients

who received more than 1 cycle of therapy, the best

overall response was PR in 12 patients (48%) and SD

in 10 patients (40%) for a CBR of 88%. Of 21 patients

with >6 months follow-up 7 had PFS R6 months

(33.3%).

NCT00998192

Gong et al.

102

Senecavirus Seneca Valley

virus (NTX-010)

NTX-010 after 4

cycles of platinum-

based chemotherapy

Systemic i.v. injection with NTX-010 in patients with

extensive stage SCLC after completion of ﬁrst-line

chemotherapy. A total of 50 patients were treated.

Study completed: median PFS was 1.7 months for

both the NTX-010 group and the placebo group;

therefore, OV as a single agent could not generate

obvious clinical responses in patients with advanced

SCLC.

NCT01017601

Schenk et al.

104

Non-

speciﬁed RT-01 RT-01 combined

with durvalumab I

Intravenous injection of RT-01 followed by

durvalumab treatment of patients with extensive-

stage SCLC. Determining efﬁcacy MTD and safety.

Study is ongoing.

NCT05205421

Herpes

simplex

virus

T3011, a genetically

modiﬁed oncolytic

herpes simplex virus

(HSV-1) strain

T3011 and

pembroluzimab I/IIA

Intratumoral injection of T3011 followed by

pembrolizumab. Total 64 patients with advanced

solid tumors, including NSCLC. Safety and MTD

measurements. The study is ongoing.

NCT04370587

R130 genetically

modiﬁed HSV-1 strain I

Intratumoral or intraperitoneal injection in patients

with advanced, refractory solid tumors (including

NSCLC). Initial MTD and safety/toxicity evaluation.

Study is ongoing.

NCT05886075

NCT05860374

12 Molecular Therapy: Oncology Vol. 32 March 2024

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blockers in combination with chemotherapy.

115

Overall, the lethality

of SCLC remains much higher than for NSCLC patients. According to

reports, patients with late-stage lung cancer have a shorter life expec-

tancy than those diagnosed with early stages. Therefore, it is essential

to develop new methods for early lung cancer diagnosis as well as

novel efﬁcient therapies to treat lung cancers in their advanced stages.

OVs for cancer therapy

Oncolytic virotherapy is a method of treating cancer by utilizing an

attenuated virus with increased tropism for tumor cells. In general, vi-

ruses are harmful germs that infect cells, engage their DNA, RNA, and

protein-synthesis machinery to reproduce, and then lyse their host

cell to distribute their offspring, spreading the infection across a tissue

(Figure 2). OVs, however, must have certain characteristics, such as

not being pathogenic, capable of targeting and eradicating cancer cells

speciﬁcally, and having the ability to be genetically engineered to

release tumor-killing proteins.

116

Table S1 shows an overview of spe-

ciﬁc features from OVs that were most frequently used against lung

cancer in various experimental settings.

The cellular tropism of each virus dictates which tissues are most

frequently infected. Different OVs with various tropism and tumor

selectivity may be inﬂuenced by the level of receptor-mediated cell

entrance, intracellular antiviral responses, or restriction factors that

control the sensitivity of the infected cell to viral gene expression

and replication.

117

Nevertheless, the ability to infect, multiply, and

lyse cells is a trait of naturally occurring lytic viruses.

This means that many OVs have their speciﬁc cell receptors, and

upon cell entry can interact with host cell factors to facilitate viral

genome replication, after which many viruses’replication cycles

take advantage of altered biological pathways in cancer cells.

118

With advances in biomolecular techniques and our improved un-

derstanding of cancer biology and virology, it became possible to

create viruses with higher tumor selectivity and enhanced oncolytic

activity.

Figure 1. Pie chart illustrating the overall prevalence

of common lung cancer (sub)types

About 80% of SCLC patients are ever-smokers vs. only

16% never-smokers. This differs signiﬁcantly for NSCLC

where about 40% are never-smokers compared with 60%

ever-smokers. Especially lung adenocarcinoma (90% vs.

35%) was higher among never-smokers than among

ever-smokers, suggesting fundamental differences in lung

cancer ontology between these two different groups of

patients.

Thus intracellular aberrations that arise in gene

expression or signaling pathways (such as RB/

E2F/p16, p53, IFN, PKR, EGFR, Ras, Wnt, anti-

apoptosis, or hypoxia) in cancer cells or tumor

microenvironment have been studied and dis-

sected with a variety of OVs such as adenovirus, HSV, poxvirus,

VSV, measles virus, Newcastle disease virus (NDV), inﬂuenza virus,

and reovirus.

117

Each of the different virus types has its own speciﬁc

set of genes responsible for viral replication and in some cases immune

evasion of the infected host cell. This knowledge facilitated the genetic

engineering of diverse OVs to target cancer cells and spare normal

cells. This especially holds for the three OV types most used against

lung cancer, namely HSV, adenovirus, and pox virus. For example,

in adenovirus, transcription of both viral immediate-early E1A and

E1B genes can be controlled by tumor-speciﬁc promoters, excluding

adenovirus replication in normal cells, such as deletion of the Delta-

24 (D24) sequence in the constant region 2 (CR2) of the E1A coding

region caused an even more attenuated virus. Here, the D24 nucleotide

sequence of CR2 encodes the RB-binding domain of E1A, which in in-

fected normal cells enables the release of E2F and subsequent viral

replication. Thereby, the Delta-24 deletion in E1A renders the adeno-

virus deﬁcient in replication in normal cells that are out of the cell cycle

in a post-mitotic status. Importantly, the 24-base pair deletion does

not compromise Ad replication in cancer cells without functional

RB expression. Resulting conditionally replicating adenovirus

(CRAd) strains could then be further optimized by inserting a short

peptide sequence with an Arg-Gly-Asp RGD motif into the HI loop

of the adenovirus knob protein, which signiﬁcantly raises its afﬁnity

with its receptor on the cell surface and causes a more efﬁcient inter-

nalization in the host cell.

119

For HSV, conditionally replicating

HSV-1 strains were speciﬁcally designed to target cancer cells.

120,121

Here, three viral genes g34.5,UL39, and a47 were deleted that encode

infected-cell protein ICP34.5, ICP6, and ICP47, respectively. Nor-

mally these three genes render wild-type HSV the ability to evade

the host antiviral response and continue its replication cycle.

Normally infection with wild-type HSV causes the activation of pro-

tein kinase R (PKR),which then phosphorylates eukaryotic initiation

factor 2a(eIF-2a) rendering it inactive and thereby leading to the in-

hibition of protein synthesis. Expression of ICP34.5 circumvents this

by dephosphorylating eIF-2aand thus allowing viral protein synthe-

sis in the infected cells.

Molecular Therapy: Oncology Vol. 32 March 2024 13

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Since PKR activity is a downstream inhibiting target of RAS and is

also otherwise often impaired in most cancers, deleting ICP34.5 will

severely attenuate HSV in normal cells only. Deletion of UL39 has

a different effect since it encodes ICP6, a large subunit in viral ribo-

nuclease reductase, which converts ribonucleotides into deoxyribo-

nucleotides that are utilized in viral genome synthesis. Lacking

ICP6 restricts viral replication to dividing cells, as mature, post-

mitotic cells lack ribonucleotide reductase expression and enough de-

oxyribonucleotides.

121

On the other hand, HSV immediately early

protein ICP47 interacts with the transporter associated with antigen

presentation (TAP), blocking the antigenic peptide transport into

the endoplasmic reticulum and subsequent loading onto major histo-

compatibility complex class I (MHC class I) molecules and presenta-

tion on the cell surface. ICP47 therefore impairs MHC class

I-dependent CD8+ T cell response against HSV-infected cells,

122

improving HSV capacity to evade viral-induced immune response.

Deletion of ICP47 attenuates HSV virulence but this can be beneﬁcial

for the removal of infected tumor cells due to the more efﬁcient pre-

sentation of tumor-associated antigens (TAAs) as we discuss below.

Comparable mechanisms to modify virulence are applied in VV,

belonging to the family of poxviruses. VV encodes a double-stranded

RNA binding protein (E3L) that prevents activation of protein kinase

PKR,

123

and an eIF-2a homolog (K3L) that blocks phosphorylation of

eIF2a.

124

Complementary to these mechanisms, VV can weaken the

binding of complement cascade through the VV expression of the

viral complement control protein (VCP) encoded by C3L

125

and

membrane-bound glycoprotein B5R,

126

which is essential for the for-

mation of an EEV form of VV. Moreover, the B5R extracellular

domain shares a high similarity with VCP and together they might

be involved in protection against host immune responses.

However, an alternative way for attenuating vaccinia virulence was

introduced through the deletion of the VV thymidine kinase (TK)

gene. TK is involved in the synthesis of deoxyribonucleotides to facil-

itate DNA replication in cells with suboptimal nucleotide precursor

pools. While the TK gene is necessary for replication in normal cells,

where intracellular nucleotide concentration tends to be low, it is not

necessary for cancer cells, which have relatively high concentrations

of intracellular nucleotides.

127

Thus, replication of the TK-deleted vi-

rus is dependent on the growth status of the host cells. Another way of

generating tumor speciﬁcity of VV through genetic engineering was

found through the deletion of the vaccinia growth factor (VGF)

gene. VGF is expressed early during the VV infection cycle and is

secreted from infected cells. It then binds growth factor receptors

on surrounding resting cells and stimulates cell proliferation, thus

preparing them for subsequent VV infection. This function is impor-

tant for VV replication in normal tissues, but dispensable in tumors

because tumor cells are naturally proliferating. Therefore, VGF dele-

tion creates VV that preferentially replicates in tumors. Deletion of

both the TK and VGF genes (double deleted VV or vvDD) was shown

to signiﬁcantly decrease pathogenicity compared with wild-type

virus.

128

Interestingly and contrary to most other OVs (Table 2),

wild-type unmodiﬁed reovirus did already show an enhanced viral

replication preference in cancer cells as compared with normal cells.

This enhanced reovirus tropism is most likely linked to activated

EGFR-RAS pathway activity connected with PKR inactivation.

129

On the other hand, both preclinical investigations and clinical trials

have demonstrated that anti-tumor therapy employing naturally on-

colytic NDV is safe and efﬁcacious.

130–132

In a preclinical experiment

using athymic mice implanted with lung cancer, Chai et al.

showed

that a reverse genetics system based on the oncolytic NDV D90 strain

(rNDV-GFP, recombinant NDV carrying an enhanced green ﬂuores-

cent protein gene), as well as the parental D90 virus, signiﬁcantly sup-

pressed body weight loss and tumor growth (Table 2).

Essential elements of OV therapy, such as systemic dissemination and

intratumoral replication, are easily monitored in vivo by adding mo-

lecular reporters into viral genomes, which has dramatically advanced

our understanding of the intricate dynamics of this strategy.

133,134

These encouraging developments have raised the possibility that

OVs may be administered intravenously to patients with advanced

and otherwise incurable illnesses to "seek and kill" metastatic deposits.

Optimal therapeutic efﬁcacy of OVs as a systemic administration re-

agent is, however, constrained because, in most situations, the evoked

Figure 2. Strategies for improving oncolytic virus efﬁcacy

Oncolytic viruses (OVs) are designed for distinct expansion within the tumor niche.

At least seven important modes of action can be elicited in tumor cells after infection

with optimized, genetically engineered OVs. The introduction of three types of

transgenic payloads in OV genomes results in the expression of angiogenesis in-

hibitors, immunostimulatory factors, and pro-drug converting enzymes. Direct ge-

netic manipulation of the OV genome might alter its intrinsic capacity to transduce

host cells and affect the viral replicative life cycle through alternations in transcrip-

tion, translation, and induction of pro-apoptosis activities. The latter intrinsic OV

genome mutation can also affect the maintenance and viral life cycle of OVs in

various carrier cell types.

14 Molecular Therapy: Oncology Vol. 32 March 2024

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anti-viral immune response restricts the lethal effects of OVs, and the

effectiveness remains low.

135–137

Four hypotheses might explain this

lack of efﬁcacy: (1) patients carry antiviral antibodies. Pre-existing an-

tibodies quickly remove OVs after systemic injection, which reduces

OV therapy efﬁcacy

138,139

. (2) Macrophages in the liver and spleen

eliminate OVs. (3) Physical barriers present a substantial hindrance

to viral transmission because, in solid tumors, OVs must penetrate

the endothelium layer to reach target cells. (4) OVs are quickly elim-

inated by the host’s immune system as a result of interactions between

OVs and antigen-presenting cells, strong antiviral immunity, pre-ex-

isting circulating antibodies, and blood factors such as platelets

140

and

complement proteins.

141,142

All these various combined factors make

it very difﬁcult to predict if enough OV particles can reach the tumor

location after systemic infection. One contemporary solution to evade

some of the delivery problems for OVs is the use of cellular carriers

(CCs) as we discuss further below.

Mechanisms of OV action

Even though the mechanisms of OV function are still not fully under-

stood, it appears that OV administration can safely cause regression

in several human cancers through both: (1) direct oncolysis in which

both infected tumor and, only by some speciﬁc OV types, simulta-

neous infected tumor-associated stroma cells

143

undergo local cell

death, and (2) promotion of the systemic immunological activity to

the tumor’s virally induced cell death

144,145

(Figure 3).

Intrinsic mechanisms

Multiple methods, including pyroptosis, apoptosis, necrosis, and au-

tophagic cell death, are used by OVs to kill cancer cells after infection.

Except for apoptosis, the remaining modes of cell death mentioned

above are very immunogenic and trigger both non-speciﬁc and

speciﬁc immune responses. When viral-infected cancer cells die,

TAAs together with danger signals, such as danger-associated

Figure 3. Mechanisms of OV therapy

(A) OVs either naturally or after genetic manipulation selectively multiply in cancerous cells. Due to viral clearance, normal cells are unaffected. Lysis of tumor cells is caused by

viral replication and the activation of cell death mechanisms. By releasing viral offspring, oncolysis makes it possible for fresh tumor cells to become infected. (B) Immuno-

stimulating effects. Oncolysis, which is brought on by virus replication, results in the production of pathogen- and damage-associated molecular pattern molecules (PAMPs

and DAMPs, respectively), as well as antigens associated with tumors (TAAs) and viruses. These antigens are subsequently absorbed by antigen-p resenting cells (APCs)

such as dendritic cells, which then induce the formation of tumor- and virus-speciﬁc T cells. At the same time, viral infection and replication trigger an inﬂammatory response,

which results in the production of chemokines and thereby attracts T cells. The latter action facilitates tumor- and virus-speciﬁc T lymphocytes to inﬁltrate into the tumor and

perform their immune function. (C) OVs as a platform for transgene delivery. Adenovirus and vaccinia virus are two examples of OVs that may be altered to carry transgenes

(armed OVs), after which transgene products can be speciﬁcally delivered to the tumor microenvironment and further stimulate an anticance r immune response.

Molecular Therapy: Oncology Vol. 32 March 2024 15

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molecular pattern (DAMP) and pathogen-associated molecular

pattern (PAMP) molecules, are released.

146

Antitumor effects

through stimulating an adaptive immune response can be seen in

distant tumor sites that were not locally treated with OV, as a result

of cytotoxic CD8+ T cell activation.

147

A range of cytokines, including interleukins, interferons, and tumor

necrosis factor-a(TNF-a), are released by dying cells into the imme-

diate environment, further enhancing cell-mediated immunity.

PAMPs, TAAs, DAMPs, and cytokines work synergistically to pro-

mote antigen-presenting cell (APC) maturation, which in turn primes

CD4+ and CD8+ T lymphocytes for the adaptive host immune

response through cross-presentation.

148

The innate immune system

is also implicated in the antitumor reaction following OV therapy,

as shown by the ability of type I IFNs and DAMPs to directly promote

natural killer (NK) cell activity against cancer cells.

149

In addition,

certain OVs also target the tumor vasculature, which results in the

loss of the tumor’s blood supply and the death of uninfected tumor

cells.

150

Enhancing OV anti-tumoral response

Just as viral gene deletion has been applied to increase the selective

infection of tumor cells by OVs, the insertion of therapeutic genes

through genetic engineering has been utilized to increase OVs’anti-

tumoral responses. In this section, we emphasize the arming of

OVs with immune-stimulating molecules, such as cytokines, mole-

cules that improve immune system cross-priming, and T cell co-stim-

ulatory molecules, as a critical method to improve anti-tumoral

responses after OV infection.

145

Numerous studies with cytokine-ex-

pressing OVs produced promising outcomes.

151,152

Several OVs

expressing cytokine granulocyte macrophage colony-stimulating fac-

tor (GM-CSF), which stimulates APC maturation and increases cyto-

toxic T lymphocyte responses against malignancies, are presently

applied in clinical studies (Table 3). The most researched GM-CSF

expressing OV is T-VEC. Sample examination from melanoma le-

sions treated with intratumoral T-VEC injection revealed that these

treatments resulted in both local and systemic T lymphocyte re-

sponses.

153

OVs expressing heat shock proteins (HSPs) are an alter-

native strategy to boost anti-tumoral immune responses. OV-infected

tumor cells undergoing oncolysis produce HSPs, which trigger the

generation of chemokines and activate dendritic cells (DCs) via the

TLR4 pathway. The innate and adaptive immune systems are cross-

primed by HSPs; hence OVs were developed to overexpress HSPs,

particularly HSP70. Adenoviral vectors that express HSP70 have

shown anticancer activity in human solid tumors from a phase I study

and in patients with xenograft models of hepatocellular carcinoma.

154

Another strategy to boost cytotoxic T lymphocyte activation against

tumor cells is to target T lymphocyte activation by designing OVs

to produce T lymphocyte co-stimulatory molecules. Costimulatory

molecules, including CD40 and CD80, are present in professional

APCs. Arming OVs by expressing CD40 ligand (CD40L) evokes an

innate response and enhances DC maturation and activation, which

in turn activates T cells. The latter effect occurs when a T-helper

response is elicited and results in cytotoxic lymphocyte (CTL) activa-

tion when CD40L, a transmembrane protein produced on CD4+

T cells, interacts with its receptor on an APC.

155

However, the func-

tional efﬁcacy of OV infection can be severely hampered by the pres-

ence of stroma surrounding solid tumor lesions. The stroma is a

multi-componential tissue, which consists of tumor-associated mac-

rophages (TAMs), the (compact) extracellular matrix, tumor vascula-

ture, and, to a large degree, cancer-associated ﬁbroblasts (CAFs),

which all together as non-epithelial, tumor-associated stromal cells

(TACs) create a proﬁcient tumor environment. TACs are of decisive

importance for tumor progression, metastasis, and therapy resistance,

by forming a barrier against inﬁltrating immune cells and anti-tumor

drugs. Some native OVs are known to target stromal components

such as CAFs or vascular endothelial cells. Only VSV has been shown

to have a natural tropism for CAFs. VSV could infect CAFs that were

associated with pancreatic tumor cells in patient-derived xenograft

models.

156

Interestingly, VSV replication in both pancreatic tumor

cells and stroma is enhanced by reciprocal signaling between tumor

cells and CAFs. Tumor cells secrete TGF-b1, which promotes VSV

infection in CAFs, and CAFs secrete FGF2, which reduces innate

anti-viral retinoic acid-inducible gene I (RIG-I) expression in pancre-

atic tumor cells. In turn, the reduced expression of RIG-I makes these

cells more permissive to viral infection.

156

Although only VV and VSV have an intrinsic capacity to target tu-

mor-associated endothelial cells and thereby disrupt vascularization,

other OVs need to adapt their viral genomes. In the latter case, OVs

are “armed”and capable of transcriptional or transductional

endothelial targeting by way of downregulating angiogenic factors

or expressing antiangiogenic molecules

157

(Table 2).

A study from

Arulanandam et al.

158

showed that tumor-dependent levels of

vascular endothelial growth factor (VEGF) repressed type I inter-

feron-mediated antiviral signaling in endothelial cells, after which

endothelial cells were sensitized for VV infection. These results

showed that intrinsic high levels of VEGF inside the tumor vascula-

ture could increase OV tropism for endothelial cells

158

and exemplify

how vascular-targeted OVs can improve cancer treatment efﬁcacy.

The last two decades have shown a steady advance in the targeted use

of other and above-mentioned engineered OVs against a broad range

of solid tumors in an extensive number of (pre)clinical trials that

conﬁrmed OVs’potential as immunotherapeutic tools too.

These promising developments coincide with the remarkable break-

through of immunotherapy using ICIs in the treatment of lung can-

cer. ICI therapies ultimately aim to vaccinate against lung cancer

through the induction of a lasting adaptive immune response against

lung tumor cells. Various vaccination technologies are currently being

developed and optimized as promising new strategies for lung cancer

therapy. Oncolytic virotherapy could certainly take its place among

these new types of immunotherapeutics since, because of their selec-

tive lysis of tumor cells, OVs can induce a lasting adaptive immune

response. In Tables 2 and 3we present an overview of most (pre)clin-

ical studies with various OVs against lung cancer. Although many

OVs show clear anti-tumor efﬁcacy in nearly all preclinical studies,

16 Molecular Therapy: Oncology Vol. 32 March 2024

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progress in clinical phase I/II studies is nevertheless slow and takes a

long time to evaluate but promising results are obtained (Table 3).

Moreover, systematic reviews and meta-analyses evaluated the efﬁ-

cacy and safety of OV in lung cancer and showed that the objective

response rate was signiﬁcantly higher in patients receiving oncolytic

adenovirus H101 monotherapy or combination with chemotherapy

than in patients only receiving chemotherapy.

159

There still is a

long way to go before the use of optimized OVs will be sophisticated

enough to become a standard part of a likely combined (immuno)

therapy against lung cancer. For this, the pitfall of systemic OV appli-

cation must be overcome.

Cellular carriers for OVs

As stated above, an entirely different way of augmenting systemic OV

therapy effectiveness can be achieved by using CCs for OVs. Ideally,

CCs protect their OV load against innate and adaptive immune re-

sponses and thereby lead to a more efﬁcient OV delivery in any tumor

bed. Not only OV but also CC characteristics determine delivery ef-

ﬁcacy and tropism and, even after optimizing these different factors,

the cellular OV delivery system’s ultimate success or failure depends

on the precise coordination of three crucial steps in space and time, as

shown in Figure 4. The CCs are ﬁrst loaded ex vivo; secondly, cells are

delivered to the tumor location through the circulatory system; and,

ﬁnally, viral release inside the tumor bed is required. Once this pro-

cess is started, it must be synchronized with the OV life cycle inside

the speciﬁc carrier cell type employed for delivery. Therefore, to guar-

antee that OV-loaded CCs reach their destination at the appropriate

moment, a thorough understanding of the process dynamics is neces-

sary.

134

This strategy resembles how some viruses have evolved to

propagate throughout their host or obtain access to other tissues.

For instance, the human immunodeﬁciency virus has been shown

to bind to circulating DCs and macrophages, which subsequently

move spontaneously to lymph nodes and spread the virus to its in-

tended target cell type, i.e., CD4+ T cells.

160

Preclinical research has

shown that most cell types investigated for use as oncolytic viral

Figure 4. Carrier cells deliver their replicating OV load via a three-stage kinetic model

(A) Typical kinetics of OV delivery using permissive cancer cells (CCs). OV-infected cellular carriers undergo an eclipse phase after the virus is ex vivo added at time zero (t = 0),

which comes before the release phase in which viral protein production, exponential ampliﬁcation, and the release of offspring vir ions take place. (B) Three stages of CC/OV

delivery that are delivered sequentially and are mapped to the duration of the viral development cycle depicted in (A) at the optimal times. Slower replicating OVs in speciﬁc

CCs can elongate the eclipse phase signiﬁcantly but might also produce a lower number of virions. The eclipse and release periods are therefore critically dependent on the

OV life cycle in its CC and unique for every speciﬁc CC/OV combination. The complete eclipse period must be long enough to facilitate a proper stealth delivery. The release

phase on the other hand should be fast enough to prevent a long time expression of viral proteins by the CCs to successfully evade adaptive barriers such as antiviral

antibody-dependent cellular clearance.

Molecular Therapy: Oncology Vol. 32 March 2024 17

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delivery systems belong to one of the three groups listed below: pro-

genitor cells, immune cells, and transformed cells. For instance,

several cell types, including mesenchymal stem cells (MSCs), cancer

cells, DCs, and blood outgrowth endothelial cells (BOECs), have

been employed to treat solid tumors

161,162

and in particular for

lung cancer as shown in Tables 2 and 4.

Each of these cell types has speciﬁc beneﬁts and possible drawbacks.

In principle, the perfect cell carrier should not only shield its viral

payload from neutralization and target it directly to the tumor site,

reducing harm to normal tissues, but the cell carrier should also

possess anticancer efﬁcacy. Additional properties, such as a favorable

safety proﬁle, ease of isolation, and/or manufacturing, are essential

features to consider when deciding which carrier cell type is most suit-

able for clinical application. An optimal CC therefore requires three

features: (1) CCs should be easily infected by virus, (2) CCs carry

the virus speciﬁcally to the tumor bed while hiding it from immune

recognition, and (3) CCs should release progeny virus to act upon

distant tumor sites. All these features must be considered for deter-

mining the CC systems best suited for each different tumor indica-

tion, especially considering the need for systemic OV applications

against lung cancer metastases.

MSCs

MSCs are immature multi-potent stem cells that can self-renew and

differentiate into various cell types such as fat cells that give rise to

marrow adipose tissue (adipocytes), muscle cells (myocytes), bone

cells (osteoblasts), and cartilage cells (chondrocytes). Apart from

placental umbilical cord tissue, MSCs can be derived from distinct

adult tissues such as bone marrow, peripheral blood, and adipose tis-

sue. MSCs infected with OVs can enhance the transport of the ther-

apeutic payload to cancer sites because of their innate tumor

tropism.

163

These cells are potential delivery vehicles to even difﬁ-

cult-to-reach metastatic neoplastic foci because they in principle pro-

tect OVs from antiviral host immune response (Figure 5). Numerous

studies demonstrated that injected MSCs can migrate in a targeted

manner (homing) to speciﬁc tissues

163

(Tables 2 and 4), including

damaged and tumor regions. A signaling cascade similar to that found

in wound healing and intrinsic characteristics of the tumor sites, such

as the degree of vascularization, the level of oxygenation, the degree of

inﬂammation, etc., causes MSCs to migrate toward the tumor bed.

164

Studies showed that administering MSCs intravenously causes signif-

icant initial trapping in the lungs,

165,166

most likely due to the large size

of MSCs and their accumulation in the capillary beds of the lung.

Following a single intravenous injection of infected MSCs, Leoni

et al.

167

found that the combination of MSCs from various sources in-

fected with a HER2-retargeted oncolytic HSV and tested in murine

models of metastatic cancers had the highest concentration of carrier

cells and viral genomes in the lungs (Table 2). For at least 2 days, viral

genomes remained throughout the body. The HSV-MSC application

considerably slowed the formation of lung metastases from subcutane-

ously (s.c.) transplanted ovarian cancer in athymic nude mice and

decreased the burden of brain metastases from breast cancer s.c. trans-

plants in NOD SCID gamma (NSG) mice by more than half. In addi-

tion, studies on the antitumor efﬁcacy of syngeneic or allogeneic mu-

rine MSCs infected with the oncolytic adenovirus ICOVIR5 (i.e.,

Celyvir system) have shown that both types of Celyvir increase the

inﬁltration of CD45+ cells and leukocytes in the center of murine

lung adenocarcinoma tumors

(Table 2). In addition, more than a

decade ago, MSCs loaded with oncolytic adenoviruses were shown

to increase the bioavailability of systemically injected oncolytic adeno-

viruses in orthotopic murine models of breast and lung cancer.

The

use of MSCs in combination with different adenoviral designs has been

widely investigated in (non)systemic therapy. Rincón et al.

used the

syngeneic murine CMT64 lung cancer cell line to produce a human

adenovirus semi-permissive tumor model. They showed the ability

of adenovirus-loaded murine MSCs (mCelyvir) homing to the trans-

planted CMT64 lung tumors. It was shown that intratumoral injec-

tions of ICOVIR5, the actual adenoviral construct, and mCelyvir

together caused a higher tumor clearance than they did separately (Ta-

ble 2). Another notable beneﬁt of this combination therapy was the

enhanced recruitment and boost of tumor-inﬁltrating CD8+ and

CD4+ T cells. Therefore, MSCs can effectively transport genetically en-

gineered OVs to solid tumors such as lung cancer,

165

and overall (pre)

clinical results suggest that systemic OV therapies using MSC carrier

systems have a perspective in lung cancer treatment (Tables 2 and 3).

Seyed-Khorrami et al.

used MSCs loaded with oncolytic reovirus in

the syngeneic mouse TC-1 lung cancer model and tested their migra-

tory potency in vivo after systemic infection and assessed the efﬁcacy

and quality of lung cancer treatment. The study’sﬁndings showed

that the effect of reovirus infection on adipose-derived MSCs does

not seriously impair their ability to migrate into the tumor bed and

that MSCs can act effectively as a vehicle for oncolytic viral delivery

into the tumor site. Another encouraging development was shown

in a study by Wang et al.

168

Here, advanced genetically engineered

enucleated MSCs kept their loading capacity for cytoplasmic-repli-

cating OVs in combination with reﬁned homing mechanisms for tu-

mor tissues. Furthermore, enucleated MSCs were prevented from

proliferating and stably engrafting in host tissues, thereby diminish-

ing unwanted side effects after systemic use of MSCs.

Immune cells

A major problem for the effective use of immune cells as carrier cells

lies in the rather poor replication capacity of OVs within these

cells.

169

While immune cells were once believed to be nothing more

than primary, albeit not efﬁcient, viral transporters to tumor loca-

tions, more recent research has concentrated on developing a synergy

between the virus and immune cells to increase the anticancer effects

of both entities. The prominent role of the host immune system in

controlling and eradicating tumors is well known. So it is tempting

to use immune cells in such a way that their natural features can be

combined with a role as OV carrier cells

170

and stimulate an even

more robust antitumor response.

171

Cytokine-induced killer (CIK) cells have been extensively used to gain

a better understanding of this synergy. CIK cells locate their targets

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through the use of their own NKG2D receptor and its ligands, such as

the stress response ligands MICA and MICB. Multiple pressures

imposed by the immune environment during its ﬁght against tumor

formation cause the elevated expression of these ligands in human

cancers

172

(Table 2). Remarkably, viral infection is a stressor as well

and thereby enhances NKG2D ligand expression. CIK cells behave

like NK cells and try to eliminate tumor cells when they encounter

them. Adoptive transfer of OV-infected CIK cells into a tumor-

bearing host led to approximately 20% of CIK cells lysing at the tumor

location and the remaining 80% attacking the tumor.

172

In addition, immuno-stimulatory mediators released by activated CIK

cells assist in generating a memory response and trigger the host

immune response.

172

Jiang et al.

(Table 2) infected CIKs with

oncolytic adenovirus ZD55-bearing TNF-related apoptosis-indu-

cing ligand (TRAIL), manganese-containing superoxide dismutase

(MnSOD), and TRAIL-isoleucine-aspartate-threonine-glutamate-

MnSOD. They showed that co-cultivation of lung cancer cell lines

with CIK cells expressing oncolytic adenoviruses dramatically

decreased the colony formation, proliferation, and invasion of these

tumor cells. The co-cultivated lung cancer cells also produced more

TNF-a, IFN-g, and lactate dehydrogenase than normal cells. More-

over, systemic injection of CIK cells harboring oncolytic adenoviruses

in a lung tumor xenograft model led to a signiﬁcant decrease in tumor

load and lower levels of Ki67-expressing tumor cells.

Other studies investigated the use of DCs as delivery vectors for OV.

Although DCs can preferentially move to tumor areas, they have a

relatively limited inherent capacity to destroy tumor cells.

173,174

How-

ever, as with other OVs, the fast generation of neutralizing antibodies

poses a signiﬁcant challenge to effective systemic administration.

Therefore, the capacity of T cells, DCs, and peripheral blood mono-

nuclear cells (PBMCs) as some types of CCs was evaluated, in how

far they could shield reovirus and myxoma virus from systemic

neutralization

41,42,94

(Table 2).

In addition, studies with reovirus

94,175

investigated how far these CCs

might inﬂuence the balance of the ensuing antiviral vs. antitumor im-

mune response. Reovirus was injected intravenously into C57Bl/6

mice harboring melanoma metastases, either in puriﬁed form or

loaded onto DCs or T cells. In both cases for naive mice, infected

by either puriﬁed OV or OV-carrier cells, OVs were detected in the

Figure 5. Advantage of systemic delivery of an MSC-shielded OV

Systemically injected unprotected OVs, such as the virus, cause an antiviral response through innate (NK cells, cytokines, mononuclear phago cyte system (MPS), com-

plement activation) and eventual adaptive (antibodies, T cell mediated) immunity, which clears the virus and prevents any oncolytic effects. On the other hand, efﬁcient

transport to the tumor bed and oncolytic activity are made possible by viruses being protected by an appropriate protective carrier, such as mesenchymal stem cells (MSCs).

The therapeutic system, or "Trojan horse," consists of MSCs infected with OVs, which improves oncolysis and raises the acquired anti-tumor immune response, enhancing

the total anticancer impact. This ﬁgure is adapted from Hadry

s et al.

Molecular Therapy: Oncology Vol. 32 March 2024 19

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Review

tumor-draining lymph nodes a few days after treatment. However,

clearance of lung metastases was only attained when the virus was

delivered on mature DCs or T cells; puriﬁed reovirus or loaded imma-

ture DCs only caused partial early tumor clearance.

BOECs

BOECs facilitate their use as CCs because they can be easily acquired

from a peripheral blood draw, rapidly produced in cell culture to large

numbers, and consistently cryopreserved without changing their

genome or phenotype,

176

which makes them very well suited for clin-

ical applications. In lung cancer and melanoma models, BOECs have

previously shown their value as gene therapy vectors for systemic de-

livery to tumors.

177

VSV is an OV that triggers a potent immunolog-

ical response, which makes it a good candidate for testing systemic

OV therapy in the context of naturally occurring immunity. Patel

et al.

(Table 2) used ex-vivo-infected BOECs to deliver VSV in pre-

clinical models of NSCLC, in which BOECs were acquired from either

C57/Bl6 mice or human donors. VSV was engineered to contain

either exogenous GFP or IFN-b, as VSV-GFP or IFN-b, respectively.

This was followed by infecting both human and murine BOECs with

either VSV-GFP or VSV-IFN-b.In vitro, both human and murine

VSV-loaded BOECs killed NSCLC cells, whereas VSV-IFN-bwas

protected against antibody neutralization. The in vivo experiments

with immune-competent mice harboring syngeneic LM2 lung metas-

tases

(Table 2) clearly showed murine BOECs localizing in the lungs

and VSV-infected murine BOECs decreased the tumor burden in this

model. The VSV-IFN-b-infected human BOECs showed improved

antitumor activity and survival in an A549 cell line xenograft model

as well since innate immunity is still largely intact in the athymic nude

mouse background.

OV-loaded tumor cells

Transformed cells have been tested as carriers for OV delivery to tu-

mors for more than two decades. Tumor cells have certain advantages

since they are easier to grow and infect with OVs compared with

normal cells, and their metastatic capacity renders them able to

home to speciﬁc organs where they can inﬁltrate metastatic tumor

beds. This would be ideal for the systemic delivery of large amounts

of viruses to metastatic tumors. Yet this is not the case for OV-loaded

transformed cells that form solid tumors such as A549 lung adenocar-

cinoma, MCF-7 breast carcinoma, HeLa cervical carcinoma, and

others. Despite their predicted efﬁcacy, the abilities of these tumor cells

to home to speciﬁc body and tumor locations after intravenous injec-

tion are rather limited due to their tendency to mostly end up in the

small capillary beds of the lung

178

as a result of their large size. Never-

theless, their limited capacity to reach metastatic tumors in these

experimental settings did not diminish their use as OV carriers to

target primary lung tumors.

The use of leukemia cells as carriers

had a somewhat better effect, although it was not clear whether the de-

livery into distal tumors was a result of random accumulation of the

infected leukemia cells rather than speciﬁc homing of these carrier

cells to the local tumor beds.

Still, transformed tumor cells do have

the capacity to metastasize and preferentially home into speciﬁc or-

gans for that matter. An example are myeloma cells expressing CXC

chemokine receptor 4 (CXCR4) and thereby facilitating their homing

into bone marrow, as has been shown in a study by Liu et al.

179

with

myeloma cells infected with the measles virus. But then again, each tu-

mor cell type would have its characteristic tissue tropism, making it

difﬁcult to use as a more general carrier cell. A personalized approach

would, however, be more tempting using a patient’s autologous tumor

cells as carriers. This would then incur the additional effect from these

infected, and after OV delivery lysed, tumor (carrier) cells as vaccines

during their systemic application.

180

How far these procedures could

be applied in clinical therapy depends obviously on the proper safety

warrants and attenuation of any tumor cell line before use.

Optimization of cell-mediated oncolytic viral therapy

It became evident that systemic application of cell carriers loaded with

OVs holds a promise for signiﬁcantly improved OV therapy against

primary lung cancer as shown in numerous (pre)clinical settings (Ta-

bles 2 and 3). Primary lung tumor lesions are well reached when OV-

loaded carrier cells accumulate inside the lung. However, this is

mostly due to lung blood vessels acting as a physical barrier to espe-

cially OV-loaded MSCs albeit to a lesser extent for other carrier cell

types. Late-stage NSCLC and almost always SCLC are nevertheless

overwhelmingly linked with aggressive metastasis formation, which

results in limited treatment options and therefore poor prognosis.

So, indeed, metastases are the main cause of high overall lethality in

lung cancer. OV therapy can only reach sufﬁcient clinical efﬁcacy if

the problem of targeting most if not all metastases has been addressed

and that is why there is an urgent need to optimize systemic (intrave-

nous) OV application against lung cancer. The latter implies a further

necessity to improve the use of cell-mediated OV therapy for optimal

clinical applications against lung cancer.

This means that the above-described direct genetically engineered

OVs with more selective tropisms and/or therapeutic gene expression

are crucial but insufﬁcient to decidedly improve the much-needed

systemic OV therapy against metastasizing lung cancer. One evident

way of circumventing liver and lung barriers would be the use of an

intra-arterial (IA) application route for OV-loaded carrier cells. IA

administration has been shown to signiﬁcantly expand the availability

and bio-distribution of MSCs.

163

In a recent phase I study

(NCT03896568), Chen et al.

181

used Ad Delta 24RGD loaded on allo-

geneic bone marrow-derived human mesenchymal stem cells via IA

in patients with recurrent glioblastoma or astrocytoma. The ﬁrst re-

sults showed that OV-MSC perfusion into brain tissue worked far su-

perior compared with the i.v. applications.

181

This method of IA

administration is potentially useful against brain metastases that often

occur during extensive-stage SCLC. Similarly, intrapleural OV

administration is much more efﬁcient than its systemic application

in causing major regression of malignant pleural disease.

182

Given

that some 50% of advanced lung cancers develop metastases that

manifest themselves as malignant pleural effusions, intrapleural

administration of OV-loaded carrier cells could be a very effective

therapeutic application, which needs to be further explored. Another

important aspect that should be emphasized in the improvement of

cell-mediated OV therapy, is the preferential use of allogenic or

20 Molecular Therapy: Oncology Vol. 32 March 2024

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Review

even better autologous carrier cells that can be derived from the pa-

tient without extensive ex vivo procedures. Together all these mea-

sures of speciﬁc systemic application routes and choice of carrier

cell types should be complemented by an improved collaboration be-

tween OV and carrier cells, which can be achieved by advanced ge-

netic engineering of either or both partners. For instance, carrier cells

can gain increased tropism for tumors through transgenic expression

of appropriate chemo- or cytokines. As we brieﬂy discussed above,

CXCR4 is a signiﬁcant candidate and CXCR4-expressing MSCs man-

ifest a more efﬁcient homing toward tumors in their inﬂamed micro-

environment.

183

However, increased tropism toward tumor or spe-

ciﬁc organ tissues can lead to some unwanted viral infection and

replication inside healthy tissue too, which then necessitates an adap-

tation of OVs so that their capacity to infect normal tissue cells is

vehemently blocked.

Notably, the myxoma virus bypasses these side effects due to its

remarkably safety proﬁle and cancer tropism. Myxoma belongs to

the pox virus family and only infects rabbits but no humans or other

non-leporid animals, while at the same time selectively infects and ly-

ses cancer cells from humans and various other species.

184

Apart from MSCs, other carrier systems based on immune cells have

the advantage of not only increasing OV bioavailability but also

combining efﬁcient tumor tropism with adoptive cell transfer. This

would then consequently link carrier-immune cell effector functions

with OV-induced oncolysis. In Table 2, we described two recent ex-

amples of this approach in preclinical lung tumor models. In the ﬁrst

approach, Sostoa et al.

used modiﬁed adenovirus ICO15K-FBiTE,

expressing FBiTE, a bispeciﬁc T cell engager against ﬁbroblast activa-

tion protein-a(FAP), which is highly overexpressed in CAFs. In a

model using transplanted human lung tumor cell line A549,

ICO15K-FBiTE together with pre-activated T cells were i.v. injected

and caused strong regression of tumor lesions and simultaneous

clearance of surrounding CAFs. CAFs can impose a major hindrance

on the inﬁltration of OVs in the tumor microenvironment and this

elegant combination of OV-directed oncolysis with FBiTE-mediated

cytotoxicity against FAP-expressing CAFs might overcome this hin-

drance on OV function.

In a second example, Barlabé et al.

used modiﬁed adenovirus

ICOVIR15-cBiTE, expressing an epidermal growth factor receptor

(EGFR)-targeting bispeciﬁc T cell engager (cBiTE) loaded on human

MSCs and systemically administered it together with allogenic

PBMCs into an A549 transplanted human lung tumor model. Due

to the high EGFR expression in A549 lung tumor cells, ICOVIR15-

cBiTE induced a much higher tumor clearance than the unarmed

ICOVIR15. Further preclinical experiments in which chimeric anti-

gen receptor-engineered T cells

161,185

or tumor-inﬁltrating lympho-

cytes were used as carrier cells

186

showed that this combinational

therapy improved tumor clearance as well as adaptive anti-tumor im-

munity. These studies demonstrated the potential of immune cell car-

riers of OVs and should be followed up with further (pre)clinical tests

in suitable lung tumor settings.

While some research groups recognized the potential of chieﬂyT

lymphocytes and secondarily myeloid cells, proof-of-concept studies

were not pursued by therapeutic reﬁnement and a progression to-

ward clinical trials. We propose that, to bring forward a real integra-

tion between carrier cells and oncolytic virotherapy, the researchers’

attention should be focused on autologous cells that can be easily

recovered from the patient without lengthy ex vivo culture or differ-

entiation steps. Furthermore, genetic engineering of OVs could be

further exploited to enhance the “collaboration”between viruses

and carrier cells, for example, to boost carrier cell migration into

the tumor bed or to achieve prolonged release of OVs from carriers

without cytopathic effects. Even if carrier cells have a very high

tropism for tumors, they will likely also accumulate in non-tumoral

tissue, which limits the viral dose delivered to the tumor and puts

the healthy tissue at risk of viral infection and replication. There-

fore, if OV-loaded carrier cells have a tropism toward a speciﬁc or-

gan (for example, the lung or the liver) it may be necessary to

modify the virus to make the normal cells from that organ specif-

ically resistant to infection.

We believe that these approaches are highly promising and that we

will be seeing more examples of immune cell carriers for OV therapies

in clinical studies soon.

Given the variety of biological tools at our disposal and our expanding

knowledge of tumor biology and cell migration, it is conceivable that,

by biologically modifying the carrier cells and/or OVs, a signiﬁcantly

improved boost in cell trafﬁcking and systemic OV delivery can be

attained.

Even with tumor-targeted cell carriers, Reale et al.

169

noted that, at

best, about 10% of all supplied cell carriers reach the target region.

Although this is a signiﬁcant improvement over the expected intrave-

nous delivery of "naked" VSV, where just 0.001% of virions reach the

tumor, there is still potential for improvement. New strategies are

already presented such as one method in which molecules are ex-

pressed or conjugated that attach to exposed tumor antigens or tumor

vasculature. The latter effect occurs after a local change in inﬂamma-

tory condition inside the tumor vasculature causes an increased

expression of several adhesion molecules, such as integrins and selec-

tins. This most likely has an important impact on OV infections since

tumor vasculature is a common characteristic of most cancer types

and several OVs are already known to infect the tumor vasculature,

reducing blood supply to the tumor because of vascular collapse.

Thus, tumor vasculature is an appealing element of tumor biology

to target OV infection.

100,187

Indeed, several studies using VV JX-

954 that speciﬁcally targets RAS/MAPK pathway

188

have been pub-

lished in which OV infections were successfully directed into the

tumor vasculature causing regression of NSCLC lesions,

100,158

and

that is why cell carriers could beneﬁt from similar targeting tech-

niques. An example of such a technique is the use of P-selectin as a

suitable conjugate. P-selectin functions as a cell adhesion molecule

on the surfaces of activated endothelial cells, which line the inner sur-

face of inﬂamed blood vessels and activated platelets in the tumor

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microenvironment. The capacity of MSCs to bind to P-selectin

in vitro is enhanced by polymer coating

189

with sialyl-Lewis X and

chemical conjugation

190

of the MSC cell surface. Similarly, enzymatic

conversion of carbohydrate groups on the MSC and T cell subset-ex-

pressed glycoprotein CD44 to the sialyl-Lewis X epitope allowed

CD44 to bind to E-selectin. Interestingly, systemic application of en-

gineered MSCs expressing P-selectin glycoprotein ligand-1 (PSGL-1)

and Sialyl-Lewis X (SLeX)

191,192

led to a speciﬁcally increased delivery

of MSCs into inﬂamed tissues. Although the latter experiments were

not performed on tumor-bearing mice, similar increased MSC deliv-

ery should likely occur in highly inﬂamed lung tumor lesions too. Be-

sides this, these engineered MSCs showed a comparable high in vivo

turnover with normal control MSCs and had markedly higher tro-

pisms for inﬂamed tissues only. Therefore, ectopic expression of

PSGL-1 and SLeX in engineered MSCs does not induce an increased

loss of MSCs during passage through the lung capillary vessels but

merely causes a more efﬁcient MSC delivery in inﬂamed tissues.

Further research is necessary to substantiate if CD44 and other alter-

nated conjugates can increase the preferential attachment of circu-

lating carrier cells to the tumor vasculature.

Another appealing strategy that may be used to treat various tumor

types is magnetic targeting since it does not rely on the carrier cell

or the expression of tumor-speciﬁc conjugates. Magnetic targeting

has been demonstrated to be feasible in guiding a wide variety of

cell types to multiple tissues for diverse purposes,

193

even though it

is more frequently used to target smaller agents to tumors, such as

drugs

194

or liposomes.

195

Modifying the tumor microenvironment

is another possible strategy to increase the trafﬁcking of carrier cells

to tumors. Using drugs or radiation, it is possible to cause the tumor

to become inﬂamed. This can raise the expression of adhesion mole-

cules, stimulate leakiness within the tumor’s blood vessels, and cause

the release of cytokines, which may facilitate the homing or extrava-

sation of carrier cells from blood vessels into the tumor.

In addition to boosting the trafﬁcking of cells to tumors, cell carriers,

and their viral payloads, can be altered to enhance many elements of

cell-mediated OV delivery, such as loading capacity, virus generation,

and delivery to tumor cells. After all, the preferred OV might not

replicate or infect a cell carrier that reaches tumors optimally. Here,

OVs can be modiﬁed or pseudo-typed if needed in such a way that

they attach to a different entrance receptor expressed by the cell car-

rier. Many drugs improving viral replication can be utilized to in-

crease virus production by the carrier cell. Of course, it must be

certain that the applied drugs do not change the carrier cell’s traf-

ﬁcking patterns during the OV-CC infection process. Besides this,

ectopic expressed immunological modulatory peptides might be de-

signed into cell carriers to either inhibit the immune response, pre-

pare the tumor for viral infection, or activate the immune system

for the second wave of attack on cancer. Next-generation cell carriers

have the potential to develop into sophisticated, mobile biological

factories that can launch a coordinated, multifaceted attack on tumors

as our knowledge of cell trafﬁcking, tumor biology, and virology

advances.

Conclusion and perspectives

There is an urgent need for improved diagnosis and treatment of lung

cancer. Since it is one of the major causes of cancer-related deaths

globally, swift progress in developing new and better therapies is of

crucial importance. OVs have great potential to reverse immunolog-

ical tumor tolerance and activate anti-tumor immunity. They can be

used as a promising new immunotherapy approach alone or in

conjunction with other treatment modalities.

196

In this review, we focus on how OVs with improved use of carrier cells

can reﬁne (immuno)therapy for lung cancer. However, the number

and type of clinical studies that were speciﬁcally performed with sys-

temically administered OV-loaded carrier cells against lung cancer

are still limited (Table 3) and mainly used MSCs as carrier cells.

Even so, experimental settings of preclinical tests showed a high vari-

ation in both OV and carrier cell types, although a major weakness in

these studies is the limited resemblance that most preclinical models

have with the complex biology of heterogeneous lung cancer. Clonal

lung cancer cell lines such as A549 are indeed a poor substitute for

advanced lung cancer, whereas replacing them with advanced somatic

mouse models for lung cancer in proper syngeneic backgrounds can

signiﬁcantly increase the physiological relevance of the preclinical

models. Besides, the use of patient-derived xenotransplant (PDX)

models ensures a better mimicking of human lung cancer, although

a drawback hereby is the need for an immune-compromised host

that impairs our potential for measuring a qualiﬁed host immune

response against applied OVs. However, some of the latter problems

can by now be bypassed through advances in genetically engineered

mouse models that generate humanized mice with a (partially) recon-

stituted human adaptive and/or innate immunity.

197,198

Although

still far from perfect, humanized mice have the advantage of allowing

OV-loaded carrier cells to be used in variable ways against orthotopi-

cally transplanted human lung cancer PDXs and measure speciﬁc hu-

man adaptive or innate immune responses after OV infection. More

recent developments even presented humanized mice in which

intrinsic murine HLA genes were replaced by human ones so that

these mice were recipients of PDX tumors as well as autologous

PBMCs from the same patient.

199

In summary, we can say that indeed

preclinical lung cancer models can be improved for better translatable

results with already available tools. We should also be realistic in ac-

cepting that murine and human immunity does have some intrinsic

differences, which apply to advanced syngeneic lung cancer models.

The humanized lung cancer models, although under continuous

development and improvement, still have their limitations too. None-

theless, a proper reﬁnement of the type and use of lung cancer models

can lead to an important improvement in the quality and efﬁcacy of

preclinical studies on OV applications with or without carrier cells.

We also should make better use of our growing insight into lung can-

cer biology in which the concept of tumor plasticity is not only a ma-

jor determining factor for intrinsic lung cancer heterogeneity and

changing tumor microenvironment (TME) interactions but also in-

ﬂuences treatment response of most if not all lung cancer types.

200

This tumor plasticity is common for lung cancer and is inﬂuenced

22 Molecular Therapy: Oncology Vol. 32 March 2024

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Review

if not governed by distinct molecular mechanisms such as epithelial-

mesenchymal transition, which leads to a dynamic shift in the differ-

entiated state of lung cancer cells. This can have major implications

for both OV and carrier cell tropism alike and should therefore be

considered during the design of each speciﬁc OV therapy for lung

cancer. OVs that infect through interaction with speciﬁc receptors

on their host cells are especially affected by tumor plasticity. For

instance, the SVV virus infects SCLC cell lines very efﬁciently due

to its direct interaction with anthrax toxin receptor 1

201

which is

only expressed in a subclass of NEUROD1-expressing SCLC.

202

Tu-

mor plasticity inﬂuences the presence and number of these

NEUROD1 subclass tumor cells during SCLC progression and that

is the likely reason that phase II trials with SVV on SCLC patients

were not successful

104

(Table 3). Contrary to this, myxoma virus

tropism for all SCLC subtypes is not hindered by the need for a spe-

ciﬁc cellular receptor and preclinical results of its use against SCLC

PDX as well as syngeneic murine SCLC models showed signiﬁcant tu-

mor clearance. So far OV immunotherapy against lung cancer has

been mainly tested in early-stage clinical trials with modest efﬁcacy.

However, it becomes clear that OVs are a very promising platform

for combination therapy in the treatment of lung cancer. As we

discussed, the steadily improved clinical use of ICIs against various

human lung cancer types presents itself as an excellent choice for

combination therapy with OVs.

Apart from the latter therapeutic synergy, we should, however, bear in

mind how canonical lung cancer therapies such as radio- but espe-

cially chemotherapy are steadily improving using newly developed

nanocarriers. Both the speciﬁcity and efﬁcacy of these therapies

advanced signiﬁcantly, including those applied for lung cancer.

203,204

Chemotherapy can have an even more profound inﬂuence on chang-

ing the immunosuppressive nature of the tumor microenvironment

after disruption of the complete tumor bed through more efﬁcient

killing of cancer cells. Further to this, a synergy of ICI and chemo-

therapy has already shown its improved efﬁcacy in clinical applica-

tions.

205

So chemotherapy certainly remains an important partner

in combination with OV therapy too, although more clinical data

are needed to substantiate this.

206

Another important aspect of

combinational ICI with chemotherapy or OV therapies in clinical tri-

als so far is the occurrence of patients undergoing complete tumor

regression (so-called "elite responders"). Although these elite re-

sponders are often only a small fraction of the total amount of patients

in each clinical trial, they are nevertheless very valuable and can offer

us a way to get important new insights into how immunotherapeutic

responses can be improved.

Since ICIs promote anti-tumor adaptive responses by removing blocks

on immune activation, which is known to break tolerance to self-anti-

gens and induce autoantibody formation,

207,208

a subset of these auto-

antibodies may thus mediate anti-tumor responses and enhance ICI

efﬁcacy. Changes in B cells and tertiary lymphoid structures have

been shown to contribute to ICI efﬁcacy too,

209,210

whereby speciﬁc

ICI-induced humoral (auto)antibody responses in elite responders

change the overall cellular adaptive immune response against a solid

cancer. Therefore, interrogation of humoral responses in cancers

from elite responders is an attractive strategy for the discovery of novel

targets and therapeutic antibodies for the treatment of cancer to exploit

synergism between ICI, chemotherapy and OV therapy.

Other encouraging prospects arise for early-stage, non-metastasized

lung cancer through local application of OVs in either the pleural cav-

ity or supported by advanced bronchoscopic techniques in the case of

parenchymal lung tumor lesions. Nevertheless, when lung cancer pre-

sents itself in its most deadly metastasizing form, OV therapy can only

secure some efﬁcacy after systemic application. And, even so, only in-

duction of a powerful anti-tumor response through OV’s immuno-

therapeutic effect can guarantee lasting remission of most if not all

metastatic lesions. Here, cell carriers play an important role in

enabling systemic delivery of OVs. As we discussed, essential features

of carrier cells are their speciﬁc tropism for tumor cells, capacity to

internalize viruses or attach them to their cell membrane, facilitate

proper viral replication, and at the same time remain viable long

enough to enable a systemic spread. These features pose a serious chal-

lenge in the advancement of carrier cell use in OV therapy, but genetic

engineering of different carrier cell types together with selective use of

adapted OVs can alleviate some of the encountered difﬁculties in (pre)

clinical use. For lung cancer, like most solid cancers, this means opti-

mization of intrinsic features of CCs such as increased tropism for pro-

inﬂammatory tissues in the case of MSCs. Increased and broadening

tropism for various cell types will, however, bear invariable risk of

accumulation in non-tumor-bearing tissue so extra care should be

given to the use of attenuated OVs with strictly limited pathogenicity

to normal tissues. Also for lung cancer (Table 2), the use of immune

cells for OV carriers remains tempting; e.g., CAR T cells can be loaded

with OVs for successfully combining both therapies.

185

CAR T cells

have a direct strong activity to kill cancer cells expressing TAAs on

the cell surface but are susceptible to the TME with its immune sup-

pressive modulators among others, such as immunosuppressive cyto-

kines, immune checkpoint inhibitory receptors and ligands (e.g.,

PD-1, PD-L1, CTLA-4), and M2 phenotype TAMs. Moreover, pre-ex-

isting TME can severely impair the level and function of tumor-inﬁl-

trating lymphocytes such as CAR T cells. As we already discussed

above, OVs remodel the TME through upregulating immune check-

point costimulatory receptors and ligands (e.g., 4-1BB, 4-1BBL,

OX40, OX40L), proinﬂammatory cytokines (e.g., IL-12, IFN, IL-6,

TNF), M1 phenotype TAMs, mature DCs, NK cells, etc. OV-mediated

oncolysis then further promotes immune activation by TAAs

spreading, which results in the proliferation of CTLs targeting other

TAAs presented by MHC in addition to CAR T cells. On the whole,

combining CAR T cell therapy and oncolytic virotherapy in a TME

should therefore beneﬁt from an immediate function of CAR T cells

followed by OV-stimulated immune activation that causes a more

effective lysis of heterogeneous cancer cell populations, which could

mitigate tumor relapse encountered by CAR T cell therapy due to an-

tigen escape.

211–213

However, one has to reckon with the most com-

mon toxicities of CAR T cell therapy, which consist of release syn-

drome (CRS) often concurrent with or shortly followed by immune

cell-associated neurotoxicity syndrome (ICANS). Also whether a

Molecular Therapy: Oncology Vol. 32 March 2024 23

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Review

combination with OV therapy mitigates CRS and ICANS is not clear,

also due to the fact that so far this combinational therapy is only being

investigated in one clinical trial, in which HER2-CAR virus-speciﬁc

T cells and a binary oncolytic adenovirus are being used to treat pa-

tients with advanced HER2-positive solid tumors (NCT03740256, Ta-

ble 3). More research is needed to optimize combinations of CAR

T cells and OVs, including their dosage, delivery, and schedule, to

maximize their efﬁcacy while minimizing toxicity.

On the other hand, oncolytic VSV, NDV, and VV induce vasculature

disruption to enhance tumor destruction,

100,214

but this may limit the

ability of intravenously delivered CAR T cells to reach the targeted tu-

mor cells. This latter defect might at least be partially reduced by

concomitant systemic application of OVs loaded on CAR T carrier

cells.

185,215

These studies show that CAR T cells loaded with albeit

low OV doses do not interfere with the function or expression of re-

ceptors in both murine and human T cells. CAR T cells readily deposit

OVs in a broad range of tissues and tumor targets and thereby

improve the applicability of CAR T and OV combinational therapies.

Many different types of OVs with tumor-selective replication and

cytolysis have been tested against lung cancer (Tables 2 and 3), but

optimal systemic application during clinical use was hampered by

the host immune system.

To warrant a more efﬁcient delivery of signiﬁcant doses of OVs to lung

cancer, diverse types of carriers have been tested that include a variety

of cell lines and immune and progenitor cells (Table 2) for lung cancer

examples. Arguably, MSCs possibly have the best potential as cell car-

riers for systemic OV delivery. In vitro and in vivo experiments with

MSC-based carrier cells have demonstrated their capacity for viral

infection and multiplication, immune evasion, and tumor tropism

production.

216

Further to this, MSC-derived carriers have shown great

promise for cancer therapy based on the results obtained in a variety of

preclinical tumor models (Table 2, ICOVIR-5/CELYVIR). The even-

tual translation of these preclinical results into clinical usage will be

revealed by the outcomes of trials such as an ongoing phase I/II inves-

tigation (NCT02068794), in which MSCs infected with oncolytic mea-

sles virus are being administered

217

or MSCs loaded with ICOVIR-5 is

being investigated in phase I/II trials (Table 3, NCT01844661 and

EudraCT no. 2008-000364-16) against refractory and metastatic solid

tumors in children and adults. Also, immune cells such as CIKs have

been successfully tested against lung cancer in a recent preclinical

study.

Here, CIKs served as CIK cells as delivery vehicles for re-

combinant adenovirus KGHV500 that expresses anti-p21Ras scFv.

According to their ﬁndings, systemic infection with combined CIK-

KGHV500 considerably slowed the growth of KRas mutated lung can-

cer xenografts when compared with mice given KGHV500 therapy

alone. KGHV500 and anti-p21Ras scFv were also detected in tumor

tissue but were hardly noticeable in normal tissues.

These results and those from many other studies continue to empha-

size the importance of carrier cells for the improved use of OV ther-

apy against not only lung cancer but most other solid cancers too.

However, as natural carrier cells are not optimized for delivering their

(viral) cargo to a particular location, other techniques, such as modi-

fying their tumor-speciﬁc ligand on the membrane surface,

169,218

have been utilized to improve their performance. Furthermore, ge-

netic engineering of OVs will lead to new OV strains with increased

oncolytic capacity and decreased pathogenicity.

219,220

Despite the potential of this approach, there are clear restrictions on

the use of cell carriers in therapy. The main issues are the necessity of

ex vivo cell infection and the cost, scalability, manufacture, and regu-

latory requirements associated with combining two extremely com-

plex biologic therapeutics into one product.

This is nevertheless

not much more restrictive when compared with other cancer immu-

notherapies such as CAR T cell therapies. Of key importance will be

the improved efﬁcacy of carrier cell-based OV delivery and, in doing

so, induce potent immunotherapy against various cancers. By extend-

ing our knowledge about the molecular mechanism of solid tumors

such as lung cancer and also improved tools for genome editing

such as CRISPR-Cas9,

221

we will be able to produce new generations

of viruses with improved innate oncolytic capacity as well as better

ability to infect broad-range carrier cell types. In parallel to this,

cell-mediated carrier techniques are being improved using carrier

cell-surface-modifying techniques.

169,218

Ultimately, all these efforts

should be combined to create optimal oncolytic viral therapies that

can be safely used in the clinic for eradicating lung solid tumors.

SUPPLEMENTAL INFORMATION

Supplemental information can be found online at https://doi.org/10.

1016/j.omton.2024.200788.

ACKNOWLEDGMENTS

We thank Ayşe Caner and Venus Zafari for their careful reading of

the manuscript and their constructive remarks.

AUTHOR CONTRIBUTIONS

G.E.N., M.F., and E.N.P. collected the literature and wrote the manu-

script. R.M. and A.B. designed, edited, and prepared the manuscript

for submission. All authors read and approved the ﬁnal manuscript.

DECLARATION OF INTERESTS

The authors declare no conﬂict of interest. This work was supported

in part by TÜSEB grant no. 2022-B-01-16483 (to R.M.), for the design

of the study; in the collection, analyses, or interpretation of data; in

the writing of the manuscript or in the decision to publish the results.

REFERENCES

1. Dorer, D.E., and Nettelbeck, D.M. (2009). Targeting cancer by transcriptional con-

trol in cancer gene therapy and viral oncolysis. Adv. Drug Deliv. Rev. 61, 554–571.

2. Hadry

s, A., Sochanik, A., McFadden, G., and Jazowiecka-Rakus, J. (2020).

Mesenchymal stem cells as carriers for systemic delivery of oncolytic viruses. Eur.

J. Pharmacol. 874, 172991.

3. Mountzios, G., Remon, J., Hendriks, L.E.L., García-Campelo, R., Rolfo, C., Van

Schil, P., Forde, P.M., Besse, B., Subbiah, V., Reck, M., et al. (2023). Immune-check-

point inhibition for resectable non-small-cell lung cancer —opportunities and chal-

lenges. Nat. Rev. Clin. Oncol. 20, 664–677.

24 Molecular Therapy: Oncology Vol. 32 March 2024

www.moleculartherapy.org

Review

4. Herbst, R.S., Morgensztern, D., and Boshoff, C. (2018). The biology and manage-

ment of non-small cell lung cancer. Nature 553, 446–454.

5. Alexander, M., Kim, S.Y., and Cheng, H. (2020). Update 2020: Management of Non-

Small Cell Lung Cancer. Lung 198, 897–907.

6. Duma, N., Santana-Davila, R., and Molina, J.R. (2019). Non-Small Cell Lung

Cancer: Epidemiology, Screening, Diagnosis, and Treatment. Mayo Clin. Proc. 94,

1623–1640.

7. van Meerbeeck, J.P., Fennell, D.A., and De Ruysscher, D.K.M. (2011). Small-cell

lung cancer. Lancet 378, 1741–1755.

8. Zugazagoitia, J., and Paz-Ares, L. (2022). Extensive-Stage Small-Cell Lung Cancer:

First-Line and Second-Line Treatment Options. J. Clin. Oncol. 40, 671–680.

9. Yang, S., Zhang, Z., and Wang, Q. (2019). Emerging therapies for small cell lung

cancer. J. Hematol. Oncol. 12, 47.

10. Wang, Y., Zou, S., Zhao, Z., Liu, P., Ke, C., and Xu, S. (2020). New insights into

small-cell lung cancer development and therapy. Cell Biol. Int. 44, 1564–1576.

11. Dock, G. (1904). The inﬂuence of complicating diseases upon leukemia. Am. J. Med.

Sci. 127, 563–592.

12. Moore, A.E. (1949). The destructive effect of the virus of Russian Far East enceph-

alitis on the transplantable mouse sarcoma 180. Cancer 2, 525–534.

13. Moore, A.E. (1954). Effects of viruses on tumors. Annu. Re v. Microbiol. 8,393–410.

14. Southam, C.M. (1976). History and prospects of immunotherapy of cancer: an

introduction. Ann. N. Y. Acad. Sci. 277,1–6.

15. Kelly, E., and Russell, S.J. (2007). History of oncolytic viruses: genesis to genetic en-

gineering. Mol. Ther. 15, 651–659.

16. Russell, S.J., and Peng, K.W. (2007). Viruses as anticancer drugs. Trends Pharmacol.

Sci. 28, 326–333.

17. Hill, C., and Carlisle, R. (2019). Achieving systemic delivery of oncolytic viruses.

Expert Opin. Drug Deliv. 16,607–620.

18. Wakimoto, H., Ikeda, K., Abe, T., Ichikawa, T., Hochberg, F.H., Ezekowitz, R.A.B.,

Pasternack, M.S., and Chiocca, E.A. (2002). The complement response against an

oncolytic virus is species-speciﬁc in its activation pathways. Mol. Ther. 5, 275–282.

19. Girgis, N.M., Dehaven, B.C., Xiao, Y., Alexander, E., Viner, K.M., and Isaacs, S.N.

(2011). The Vaccinia virus complement control protein modulates adaptive im-

mune responses during infection. J. Virol. 85, 2547–2556.

20. Hook, L.M., Lubinski, J.M., Jiang, M., Pangburn, M.K., and Friedman, H.M. (2006).

Herpes simplex virus type 1 and 2 glycoprotein C prevents complement-mediated

neutralization induced by natural immunoglobulin M antibody. J. Virol. 80,

4038–4046.

21. Iankov, I.D., Blechacz, B., Liu, C., Schmeckpeper, J.D., Tarara, J.E., Federspiel, M.J.,

Caplice, N., and Russell, S.J. (2007). Infected cell carriers: a new strategy for systemic

delivery of oncolytic measles viruses in cancer virotherapy. Mol. Ther. 15, 114–122.

22. Power, A.T., Wang, J., Falls, T.J., Paterson, J.M., Parato, K.A., Lichty, B.D., Stojdl,

D.F., Forsyth, P.A.J., Atkins, H., and Bell, J.C. (2007). Carrier cell-based delivery

of an oncolytic virus circumvents antiviral immunity. Mol. Ther. 15, 123–130.

23. Hirasawa, K., Nishikawa, S.G., Norman, K.L., Coffey, M.C., Thompson, B.G., Yoon,

C.S., Waisman, D.M., and Lee, P.W.K. (2003). Systemic reovirus therapy of metasta-

tic cancer in immune-competent mice. Cancer Res. 63, 348–353.

24. Ikeda, K., Ichikawa, T., Wakimoto, H., Silver, J.S., Deisboeck, T.S., Finkelstein, D.,

Harsh, G.R., 4th, Louis, D.N., Bartus, R.T., Hochberg, F.H., and Chiocca, E.A.

(1999). Oncolytic virus therapy of multiple tumors in the brain requires suppression

of innate and elicited antiviral responses. Nat. Med. 5, 881–887.

25. Tsai, V., Johnson, D.E., Rahman, A., Wen, S.F., LaFace, D., Philopena, J., Nery, J.,

Zepeda, M., Maneval, D.C., Demers, G.W., and Ralston, R. (2004). Impact of human

neutralizing antibodies on antitumor efﬁcacy of an oncolytic adenovirus in a murine

model. Clin. Cancer Res. 10, 7199–7206.

26. Lang, S.I., Giese, N.A., Rommelaere, J., Dinsart, C., and Cornelis, J.J. (2006).

Humoral immune responses against minute virus of mice vectors. J. Gene Med. 8,

1141–1150.

27. Liu, Z., Ge, Y., Wang, H., Ma, C., Feist, M., Ju, S., Guo, Z.S., and Bartlett, D.L. (2018).

Modifying the cancer-immune set point using vaccinia virus expressing re-designed

interleukin-2. Nat. Commun. 9, 4682.

28. Wang, L.-C.S., Lynn, R.C., Cheng, G., Alexander, E., Kapoor, V., Moon, E.K., Sun, J.,

Fridlender, Z.G., Isaacs, S.N., Thorne, S.H., and Albelda, S.M. (2012). Treating

Tumors With a Vaccinia Virus Expressing IFNbIllustrates the Complex

Relationships Between Oncolytic Ability and Immunogenicity. Mol. Ther. 20,

736–748.

29. Yang, M., Giehl, E., Feng, C., Feist, M., Chen, H., Dai, E., Liu, Z., Ma, C.,

Ravindranathan, R., Bartlett, D.L., et al. (2021). IL-36g-armed oncolytic virus exerts

superior efﬁcacy through induction of potent adaptive antitumor immunity. Cancer

Immunol. Immunother. 70, 2467–2481.

30. Chen, L., Chen, H., Ye, J., Ge, Y., Wang, H., Dai, E., Ren, J., Liu, W., Ma, C., Ju, S.,

et al. (2021). Intratumoral expression of interleukin 23 variants using oncolytic

vaccinia virus elicit potent antitumor effects on multiple tumor models via tumor

microenvironment modulation. Theranostics 11, 6668–6681.

31. Remy-Ziller, C., Thioudellet, C., Hortelano, J., Gantzer, M., Nourtier, V.,

Claudepierre, M.C., Sansas, B., Préville, X., Bendjama, K., Quemeneur, E., and

Rittner, K. (2018). Sequential administration of MVA-based vaccines and PD-1/

PD-L1-blocking antibodies confers measurable beneﬁts on tumor growth and sur-

vival: Preclinical studies with MVA-bGal and MVA-MUC1 (TG4010) in a murine

tumor model. Hum. Vaccin. Immunother. 14, 140–145.

32. Hu, J., Wang, H., Gu, J., Liu, X., and Zhou, X. (2018). Trail armed oncolytic poxvirus

suppresses lung cancer cell by inducing apoptosis. Acta Biochim. Biophys. Sin. 50,

1018–1027.

33. Hofmann, E., Weibel, S., and Szalay, A.A. (2014). Combination treatment with on-

colytic Vaccinia virus and cyclophosphamide results in synergistic antitumor effects

in human lung adenocarcinoma bearing mice. J. Transl. Med. 12, 197.

34. Kirn, D.H., Wang, Y., Liang, W., Contag, C.H., and Thorne, S.H. (2008). Enhancing

poxvirus oncolytic effects through increased spread and immune evasion. Cancer

Res. 68, 2071–2075.

35. Thorne, S.H., Negrin, R.S., and Contag, C.H. (2006). Synergistic antitumor effects of

immune cell-viral biotherapy. Science 311, 1780–1784.

36. Ahmed, J., Chard, L.S., Yuan, M., Wang, J., Howells, A., Li, Y., Li, H., Zhang, Z., Lu,

S., Gao, D., et al. (2020). A new oncolytic V accinia virus augments antitumor im-

mune responses to prevent tumor recurrence and metastasis after surgery.

J. Immunother. Cancer 8, e000415.

37. Frentzen, A., Yu, Y.A., Chen, N., Zhang, Q., Weibel, S., Raab, V., and Szalay, A.A.

(2009). Anti-VEGF single-chain antibody GLAF-1 encoded by oncolytic vaccinia vi-

rus signiﬁcantly enhances antitumor therapy. Proc. Natl. Acad. Sci. USA 106,

12915–12920.

38. Yu, F., Wang, X., Guo, Z.S., Bartlett, D.L., Gottschalk, S.M., and Song, X.T. (2014).

T-cell engager-armed oncolytic vaccinia virus signiﬁcantly enhances antitumor

therapy. Mol. Ther. 22, 102–111.

39. Kellish, P., Shabashvili, D., Rahman, M.M., Nawab, A., Guijarro, M.V., Zhang, M.,

Cao, C., Moussatche, N., Boyle, T., Antonia, S., et al. (2019). Oncolytic virotherapy

for small-cell lung cancer induces immune inﬁltration and prolongs survival. J. Clin.

Invest. 129, 2279–2292.

40. Jazowiecka-Rakus, J., Sochanik, A., Rusin, A., Hadry

s, A., Fidyk, W., Villa, N.,

Rahman, M.M., Chmielik, E., Franco, L.S., and McFadden, G. (2020). Myxoma

Virus-Loaded Mesenchymal Stem Cells in Experimental Oncolytic Therapy of

Murine Pulmonary Melanoma. Mol. Ther. Oncolytics 18, 335–350.

41. Christie, J.D., Appel, N., Canter, H., Achi, J.G., Elliott, N.M., de Matos, A.L., Franco,

L., Kilbourne, J., Lowe, K., Rahman, M.M., et al. (2021). Systemic delivery of TNF-

armed myxoma virus plus immune checkpoint inhibitor eliminates lung metastatic

mouse osteosarcoma. Mol. Ther. Oncolytics 22, 539–554.

42. Christie, J.D., Appel, N., Zhang, L., Lowe, K., Kilbourne, J., Daggett-Vondras, J.,

Elliott, N., Lucas, A.R., Blattman, J.N., Rahman, M.M., and McFadden, G. (2022).

Systemic Delivery of mLIGHT-Armed Myxoma Virus Is Therapeutic for Later-

Stage Syngeneic Murine Lung Metastatic Osteosarcoma. Cancers 14, 337.

43. Hotani, T., Mizuguchi, H., and Sakurai, F. (2019). Systemically Administered

Reovirus-Induced Downregulation of Hypoxia Inducible Factor-1ain

Subcutaneous Tumors. Mol. Ther. Oncolytics 12, 162–172.

44. Seyed-Khorrami, S.M., Soleimanjahi, H., Soudi, S., and Habibian, A. (2021). MSCs

loaded with oncolytic reovirus: migration and in vivo virus delivery potential for

Molecular Therapy: Oncology Vol. 32 March 2024 25

www.moleculartherapy.org

Review

evaluating anti-cancer effect in tumor-bearing C57BL/6 mice. Cancer Cell Int.

21, 244.

45. Zhao, D., Chen, P., Yang, H., Wu, Y., Zeng, X., Zhao, Y., Wen, Y., Zhao, X., Liu, X.,

Wei, Y., and Li, Y. (2013). Live attenuated measles virus vaccine induces apoptosis

and promotes tumor regression in lung cancer. Oncol. Rep. 29, 199–204.

46. Boisgerault, N., Guillerme, J.B., Pouliquen, D., Mesel-Lemoine, M., Achard, C.,

Combredet, C., Fonteneau, J.F., Tangy, F., and Grégoire, M. (2013). Natural onco-

lytic activity of live-attenuated measles virus against human lung and colorectal ad-

enocarcinomas. BioMed Res. Int. 2013, 387362.

47. Masemann, D., Köther, K., Kuhlencord, M., Varga, G., Roth, J., Lichty, B.D., Rapp,

U.R., Wixler, V., and Ludwig, S. (2018). Oncolytic inﬂuenza virus infection

restores immunocompetence of lung tumor-associated alveolar macrophages.

OncoImmunology 7, e1423171.

48. Li, J.-M., Kao, K.-C., Li, L.-F., Yang, T.-M., Wu, C.-P., Horng, Y.-M., Jia, W.W.G.,

and Yang, C.-T. (2013). MicroRNA-145 regulates oncolytic herpes simplex

virus-1 for selective killing of human non-small cell lung cancer cells. Virol. J.

10, 241.

49. Leoni, V., Gatta, V., Palladini, A., Nicoletti, G., Ranieri, D., Dall’Ora, M., Grosso, V.,

Rossi, M., Alviano, F., Bonsi, L., et al. (2015). Systemic delivery of HER2-retargeted

oncolytic-HSV by mesenchymal stromal cells protects from lung and brain metas-

tases. Oncotarget 6, 34774–34787.

50. Chaurasiya, S., Chen, N.G., Lu, J., Martin, N., Shen, Y., Kim, S.-I., Warner, S.G.,

Woo, Y., and Fong, Y. (2020). A chimeric poxvirus with J2R (thymidine kinase)

deletion shows safety and anti-tumor activity in lung cancer models. Cancer Gene

Ther. 27, 125–135.

51. Miyamoto, S., Inoue, H., Nakamura, T., Yamada, M., Sakamoto, C., Urata, Y.,

Okazaki, T., Marumoto, T., Takahashi, A., Takayama, K., et al. (2012).

Coxsackievirus B3 is an oncolytic virus with immunostimulatory properties that

is active against lung adenocarcinoma. Cancer Res. 72, 2609–2621.

52. Deng, H., Liu, H., de Silva, T., Xue, Y., Mohamud, Y., Ng, C.S., Qu, J., Zhang, J., Jia,

W.W.G., Lockwood, W.W., and Luo, H. (2019). Coxsackievirus Type B3 Is a Potent

Oncolytic Virus against KRAS-Mutant Lung Adenocarcinoma. Mol. Ther.

Oncolytics 14, 266–278.

53. Liu, H., Xue, Y.C., Deng, H., Mohamud, Y., Ng, C.S., Chu, A., Lim, C.J., Lockwood,

W.W., Jia, W.W.G., and Luo, H. (2020). MicroRNA Modiﬁcation of Coxsackievirus

B3 Decreases Its Toxicity, while Retaining Oncolytic Potency against Lung Cancer.

Mol. Ther. Oncolytics 16, 207–218.

54. Qiu, W., Ding, X., Li, S., He, Y., and Zhu, L. (2021). Oncolytic Bovine Herpesvirus 1

Inhibits Human Lung Adenocarcinoma A549 Cell Proliferation and Tumor Growth

by Inducing DNA Damage. Int. J. Mol. Sci. 22, 8582.

55. Yurchenko, K.S., Zhou, P., Kovner, A.V., Zavjalov, E.L., Shestopalova, L.V., and

Shestopalov, A.M. (2018). Oncolytic effect of wild-type Newcastle disease virus iso-

lates in cancer cell lines in vitro and in vivo on xenograft model. PLoS One 13,

e0195425.

56. Ye, T., Jiang, K., Wei, L., Barr, M.P., Xu, Q., Zhang, G., Ding, C., Meng, S., and Piao,

H. (2018). Oncolytic Newcastle disease virus induces autophagy-dependent immu-

nogenic cell death in lung cancer cells. Am. J. Cancer Res. 8, 1514–1527.

57. Hu, L., Sun, S., Wang, T., Li, Y., Jiang, K., Lin, G., Ma, Y., Barr, M.P., Song, F., Zhang,

G., and Meng, S. (2015). Oncolytic newcastle disease virus trigger s cell death of lung

cancer spheroids and is enhanced by pharmacological inhibition of autoph agy. Am.

J. Cancer Res. 5, 3612–3623.

58. Yaacov, B., Eliahoo, E., Lazar, I., Ben-Shlomo, M., Greenbaum, I., Panet, A., and

Zakay-Rones, Z. (2008). Selective oncolytic effect of an attenuated Newcastle disease

virus (NDV-HUJ) in lung tumors. Cancer Gene Ther. 15, 795–807.

59. Chai, Z., Zhang, P., Fu, F., Zhang, X., Liu, Y., Hu, L., and Li, X. (2014). Oncolytic

therapy of a recombinant Newcastle disease virus D90 strain for lung cancer.

Virol. J. 11, 84.

60. Lei, J., Li, Q.H., Yang, J.L., Liu, F., Wang, L., Xu, W.M., and Zhao, W.X. (2015). The

antitumor effects of oncolytic adenovirus H101 against lung cancer. Int. J. Oncol. 47,

555–562.

61. Song, G., Fang, J., Shang, C., Li, Y., Zhu, Y., Xiu, Z., Sun, L., Jin, N., and Li, X. (2021).

Ad-apoptin inhibits glycolysis, migration and invasion in lung cancer cells targeting

AMPK/mTOR signaling pathway. Exp. Cell Res. 409, 112926.

62. Zhang, J.-F., Wei, F., Wang, H.-P., Li, H.-M., Qiu, W., Ren, P.-K., Chen, X.-F., and

Huang, Q. (2010). Potent anti-tumor activity of telomerase-dependent and HSV-TK

armed oncolytic adenovirus for non-small cell lung cancer in vitro and in vivo.

J. Exp. Clin. Cancer Res. 29, 52.

63. Gomez-Gutierrez, J.G., Nitz, J., Sharma, R., Wechman, S.L., Riedinger, E., Martinez-

Jaramillo, E., Sam Zhou, H., and McMasters, K.M. (2016). Combined therapy of on-

colytic adenovirus and temozolomide enhances lung cancer virotherapy in vitro and

in vivo. Virology 487, 249–259.

64. Liu, D., Kojima, T., Ouchi, M., Kuroda, S., Watanabe, Y., Hashimoto, Y., Onimatsu,

H., Urata, Y., and Fujiwara, T. (2009). Preclinical evaluation of synergistic effect of

telomerase-speciﬁc oncolytic virotherapy and gemcitabine for human lung cancer.

Mol. Cancer Ther. 8, 980–987.

65. Dias, J.D., Hemminki, O., Diaconu, I., Hirvinen, M., Bonetti, A., Guse, K.,

Escutenaire, S., Kanerva, A., Pesonen, S., Löskog, A., et al. (2012). Targeted cancer

immunotherapy with oncolytic adenovirus coding for a fully human monoclonal

antibody speciﬁc for CTLA-4. Gene Ther. 19, 988–998.

66. Hakkarainen, T., Särkioja, M., Lehenkari, P., Miettinen, S., Ylikomi, T., Suuronen,

R., Desmond, R.A., Kanerva, A., and Hemminki, A. (2007). Human mesenchymal

stem cells lack tumor tropism but enhance the antitumor activity of oncolytic ade-

noviruses in orthotopic lung and breast tumors. Hum. Gene Ther. 18, 627–641.

67. Saito, A., Morishita, N., Mitsuoka, C., Kitajima, S., Hamada, K., Lee, K.M.,

Kawabata, M., Fujisawa, M., and Shirakawa, T. (2011). Intravenous injection of irra-

diated tumor cell vaccine carrying oncolytic adenovirus suppressed the growth of

multiple lung tumors in a mouse squamous cell carcinoma model. J. Gene Med.

13, 353–361.

68. Rao, J.S., Gondi, C., Chetty, C., Chittivelu, S., Joseph, P.A., and Lakka, S.S. (2005).

Inhibition of invasion, angiogenesis, tumor growth, and metastasis by adenovirus-

mediated transfer of antisense uPAR and MMP-9 in non-small cell lung cancer cells.

Mol. Cancer Ther. 4, 1399–1408.

69. Hamada, K., Zhang, T., Desaki, J., Nakashiro, K.i., Itoh, H., Tani, K., Koyama, Y.,

and Hamakawa, H. (2010). Carrier cell-mediated cell lysis of squamous cell carci-

noma cells by squamous cell carcinoma antigen 1 promoter-driven oncolytic adeno-

virus. J. Gene Med. 12, 545–554.

70. Sostoa, J., Fajardo, C.A., Moreno, R., Ramos, M.D., Farrera-Sal, M., and Alemany, R.

(2019). Targeting the tumor stroma with an oncolytic adenovirus secreting a ﬁbro-

blast activation protein-targeted bispeciﬁc T-cell engager. J. Immunother. Cancer

7, 19.

71. Freedman, J.D., Duffy, M.R., Lei-Rossmann, J., Muntzer, A., Scott, E.M., Hagel, J.,

Campo, L., Bryant, R.J., Verrill, C., Lambert, A., et al. (2018). An Oncolytic Virus

Expressing a T-cell Engager Simultaneously Targets Cancer and Immunosuppressive

Stromal Cells. Cancer Res. 78,6852–6865.

72. Lin, X.R., Zhou, X.L., Feng, Q., Pan, X.Y., Song, S.L., Fang, H., Lei, J., and Yang, J.L.

(2019). CIK cell-based delivery of recombinant adenovirus KGHV500 carrying the

anti-p21Ras scFv gene enhances the anti-tumor effect and safety in lung cancer.

J. Cancer Res. Clin. Oncol. 145, 1123–1132.

73. Jiang, R., Zhang, Z., Liao, X., Huang, L., Liao, Y., and Deng, W. (2021). Combination

of oncolytic adenovirus ZD55 harboring TRAIL-IETD-MnSOD and cytokine-

induced killer cells against lung cancer. Ann. Transl. Med. 9, 1527.

74. Hoyos, V., Del Bufalo, F., Yagyu, S., Ando, M., Dotti, G., Suzuki, M., Bouchier-

Hayes, L., Alemany, R., and Brenner, M.K. (2015). Mesenchymal Stromal Cells

for Linked Delivery of Oncolytic and Apoptotic Adenoviruses to Non-small-cell

Lung Cancers. Mol. Ther. 23, 1497–1506.

75. Moreno, R., Fajardo, C.A., Farrera-Sal, M., Perisé-Barrios, A.J., Morales-Molina, A.,

Al-Zaher, A.A., García-Castro, J., and Alemany, R. (2019). Enhanced Antitumor

Efﬁcacy of Oncolytic Adenovirus-loaded Menstrual Blood-derived Mesenchymal

Stem Cells in Combination with Peripheral Blood Mononuclear Cells. Mol.

Cancer Ther. 18, 127–138.

76. Rincón, E., Cejalvo, T., Kanojia, D., Alfranca, A., Rodríguez-Milla, M.Á., Gil Hoyos,

R.A., Han, Y., Zhang, L., Alemany, R., Lesniak, M.S., and García-Castro, J. (2017).

Mesenchymal stem cell carriers enhance antitumor efﬁcacy of oncolytic adenovi-

ruses in an immunocompetent mouse model. Oncotarget 8, 45415–45431.

77. Morales-Molina, Á., Gambera, S., Cejalvo, T., Moreno, R., Rodríguez-Milla, M.Á.,

Perisé-Barrios, A.J., and García-Castro, J. (2018). Antitumor virotherapy using

26 Molecular Therapy: Oncology Vol. 32 March 2024

www.moleculartherapy.org

Review

syngeneic or allogeneic mesenchymal stem cell carriers induces systemic immune

response and intratumoral leukocyte inﬁltration in mice. Cancer Immunol.

Immunother. 67, 1589–1602.

78. Barlabé, P., Sostoa, J.d., Fajardo, C.A., Alemany, R., and Moreno, R. (2020).

Enhanced antitumor efﬁcacy of an oncolytic adenovirus armed with an EGFR-tar-

geted BiTE using menstrual blood-derived mesenchymal stem cells as carriers.

Cancer Gene Ther. 27, 383–388.

79. Das, K., Belnoue, E., Rossi, M., Hofer, T., Danklmaier, S., Nolden, T., Schreiber,

L.-M., Angerer, K., Kimpel, J., Hoegler, S., et al. (2021). A modular self-adjuvanting

cancer vaccine combined with an oncolytic vaccine induces potent antitumor im-

munity. Nat. Commun. 12, 5195.

80. Ram, P., Tung, N., Sharma, H., Fulton, B., Peng, K.-W., Russell, S., Mohrs, M.,

Thurston, G., Kyratsous, C., Baum, A., et al. (2022). 851 Voyager V1 (VV1) onco-

lytic virus combined with immune checkpoint therapy boosts CTL responses to

multiple tumor antigens and correspondingly deepens tumor responses in murine

models of melanoma, lung and colon cancer. Journal for ImmunoTherapy of

Cancer 10, A890.

81. Patel, M.R., Jacobson, B.A., Ji, Y., Hebbel, R.P., and Kratzke, R.A. (2020). Blood

Outgrowth Endothelial Cells as a Cellular Carrier for Oncolytic Vesicular

Stomatitis Virus Expressing Interferon-bin Preclinical Models of Non-Small Cell

Lung Cancer. Transl. Oncol. 13, 100782.

82. Patel, M.R., and Kratzke, R.A. (2013). Oncolytic virus therapy for cancer: the ﬁrst

wave of translational clinical trials. Transl. Res. 161, 355–364.

83. Andtbacka, R.H.I., Kaufman, H.L., Collichio, F., Amatruda, T., Senzer, N., Chesney,

J., Delman, K.A., Spitler, L.E., Puzanov, I., Agarwala, S.S., et al. (2015). Talimogene

Laherparepvec Improves Durable Response Rate in Patients With Advanced

Melanoma. J. Clin. Oncol. 33, 2780–2788.

84. Bommareddy, P.K., Patel, A., Hossain, S., and Kaufman, H.L. (2017). Talimogene

Laherparepvec (T-VEC) and Other Oncolytic Viruses for the Treatment of

Melanoma. Am. J. Clin. Dermatol. 18,1–15.

85. Shmuylovich, L., McEvoy, A.M., Fields, R.C., Hernandez-Aya, L., Ansstas, G., and

Chen, D.Y. (2022). Durable melanoma control following disseminated talimogene

laherparepvec herpetic infection. JAAD Case Rep. 29, 131–133.

86. Tesfay, M.Z., Kirk, A.C., Hadac, E.M., Griesmann, G.E., Federspiel, M.J., Barber,

G.N., Henry, S.M., Peng, K.W., and Russell, S.J. (2013). PEGylation of vesicular sto-

matitis virus extends virus persistence in blood circulation of passively immunized

mice. J. Virol. 87, 3752–3759.

87. Cook, M., and Chauhan, A. (2020). Clinical Application of Oncolytic Viruses: A

Systematic Review. Int. J. Mol. Sci. 21, 7505.

88. Kirn, D.H., and Thorne, S.H. (2009). Targeted and armed oncolytic poxviruses: a

novel multi-mechanistic therapeutic class for cancer. Nat. Rev. Cancer 9,64–71.

89. Nakatake, M., Kurosaki, H., Kuwano, N., Horita, K., Ito, M., Kono, H., Okamura, T.,

Hasegawa, K., Yasutomi, Y., and Nakamura, T. (2019). Partial Deletion of

Glycoprotein B5R Enhances Vaccinia Virus Neutralization Escape while

Preserving Oncolytic Function. Mol. Ther. Oncolytics 14, 159–171.

90. Kirn, D.H., Wang, Y., Liang, W., Contag, C.H., and Thorne, S.H. (2008). Enhancing

Poxvirus Oncolytic Effects through Increased Spread and Immune Evasion. Cancer

Res. 68, 2071–2075.

91. Peng, K.W., Myers, R., Greenslade, A., Mader, E., Greiner, S., Federspiel, M.J.,

Dispenzieri, A., and Russell, S.J. (2013). Using clinically approved cyclophospha-

mide regimens to control the humoral immune response to oncolytic viruses.

Gene Ther. 20, 255–261.

92. Almstätter, I., Mykhaylyk, O., Settles, M., Altomonte, J., Aichler, M., Walch, A.,

Rummeny, E.J., Ebert, O., Plank, C., and Braren, R. (2015). Characterization of mag-

netic viral complexes for targeted delivery in oncology. Theranostics 5, 667–685.

93. García-Castro, J., Martínez-Palacio, J., Lillo, R., García-Sánchez, F., Alemany, R.,

Madero, L., Bueren, J.A., and Ramírez, M. (2005). Tumor cells as cellular vehicles

to deliver gene therapies to metastatic tumors. Cancer Gene Ther. 12, 341–349.

94. Ilett, E.J., Prestwich, R.J., Kottke, T., Errington, F., Thompson, J.M., Harrington, K.J.,

Pandha, H.S., Coffey, M., Selby, P.J., Vile, R.G., and Melcher, A.A. (2009). Dendritic

cells and T cells deliver oncolytic reovirus for tumour killing despite pre-existing

anti-viral immunity. Gene Ther. 16, 689–699.

95. Garcia-Carbonero, R., Salazar, R., Duran, I., Osman-Garcia, I., Paz-Ares, L., Bozada,

J.M., Boni, V., Blanc, C., Seymour, L., Beadle, J., et al. (2017). Phase 1 study of intra-

venous administration of the chimeric adenovirus enadenotucirev in patients un-

dergoing primary tumor resection. J. Immunother. Cancer 5, 71.

96. Tanoue, K., Rosewell Shaw, A., Watanabe, N., Porter, C., Rana, B., Gottschalk, S.,

Brenner, M., and Suzuki, M. (2017). Armed Oncolytic Adenovirus-Expressing

PD-L1 Mini-Body Enhances Antitumor Effects of Chimeric Antigen Receptor T

Cells in Solid Tumors. Cancer Res. 77, 2040–2051.

97. Ruano, D., López-Martín, J.A., Moreno, L., Lassaletta, Á., Bautista, F., Andión, M.,

Hernández, C., González-Murillo, Á., Melen, G., Alemany, R., et al. (2020). First-in-

Human, First-in-Child Trial of Autologous MSCs Carrying the Oncolytic Virus

Icovir-5 in Patients with Advanced Tumors. Mol. Ther. 28, 1033–1042.

98. Ramlau, R., Quoix, E., Rolski, J., Pless, M., Lena, H., Lévy, E., Krzakowski, M., Hess,

D., Tartour, E., Chenard, M.-P., et al. (2008). A Phase II Study of Tg4010 (Mva-

Muc1-Il2) in Association with Chemotherapy in Patients with Stage III/IV Non-

small Cell Lung Cancer. J. Thorac. Oncol. 3, 735–744.

99. Quoix, E., Lena, H., Losonczy, G., Forget, F., Chouaid, C., Papai, Z., Gervais, R.,

Ottensmeier, C., Szczesna, A., Kazarnowicz, A., et al. (2016). TG4010 immuno-

therapy and ﬁrst-line chemotherapy for advanced non-small-cell lung cancer

(TIME): results from the phase 2b part of a randomised, double-blind, placebo-

controlled, phase 2b/3 trial. Lancet Oncol. 17, 212–223.

100. Breitbach, C.J., Arulanandam, R., De Silva, N., Thorne, S.H., Patt, R., Daneshmand,

M., Moon, A., Ilkow, C., Burke, J., Hwang, T.H., et al. (2013). Oncolytic vaccinia vi-

rus disrupts tumor-associated vasculature in humans. Cancer Res. 73, 1265–1275.

101. Bradbury, P.A., Morris, D.G., Nicholas, G., Tu, D., Tehfe, M., Gof ﬁn, J.R., Shepherd,

F.A., Gregg, R.W., Rothenstein, J., Lee, C., et al. (2018). Canadian Cancer Trials

Group (CCTG) IND211: A randomized trial of pelareorep (Reolysin) in patients

with previously treated advanced or metastatic non-small cell lung cancer receiving

standard salvage therapy. Lung Cancer 120, 142–148.

102. Gong, J., Sachdev, E., Mita, A.C., and Mita, M.M. (2016). Clinical development of

reovirus for cancer therapy: An oncolytic virus with immune-mediated antitumor

activity. World J. Methodol. 6,25–42.

103. Villalona-Calero, M.A., Lam, E., Otterson, G.A., Zhao, W., Timmons, M.,

Subramaniam, D., Hade, E.M., Gill, G.M., Coffey, M., Selvaggi, G., et al. (2016).

Oncolytic reovirus in combination with chemotherapy in metastatic or recurrent

non–small cell lung cancer patients with KRAS-activated tumors. Cancer 122,

875–883.

104. Schenk, E.L., Mandrekar, S.J., Dy, G.K., Aubry, M.C., Tan, A.D., Dakhil, S.R., Sachs,

B.A., Nieva, J.J., Bertino, E., Lee Hann, C., et al. (2020). A Randomized Double-Blind

Phase II Study of the Seneca Valley Virus (NTX-010) versus Placebo for Patients

with Extensive-Stage SCLC (ES SCLC) Who Were Stable or Responding after at

Least Four Cycles of Platinum-Based Chemotherapy: North Central Cancer

Treatment Group (Alliance) N0923 Study. J. Thorac. Oncol. 15, 110–119.

105. Sung, H., Ferlay, J., Siegel, R.L., Laversanne, M., Soerjomataram, I., Jemal, A., and

Bray, F. (2021). Global Cancer Statistics 2020: GLOBOCAN Estimates of

Incidence and Mortality Worldwide for 36 Cancers in 185 Countries. CA. Cancer

J. Clin. 71, 209–249.

106. Yuan, M., Huang, L.L., Chen, J.H., Wu, J., and Xu, Q. (2019). The emerging treat-

ment landscape of targeted therapy in non-small-cell lung cancer. Signal

Transduct. Target. Ther. 4, 61.

107. Wang, C., Long, Y., Li, W., Dai, W., Xie, S., Liu, Y., Zhang, Y., Liu, M., Tian, Y., Li, Q.,

and Duan, Y. (2020). Exploratory study on classiﬁcation of lung cancer subtypes

through a combined K-nearest neighbor classiﬁer in breathomics. Sci. Rep. 10, 5880.

108. Cortés-Jofré, M., Uranga, R., Torres Pombert, A., Arango Prado, M.D.C., Caballero

Aguirrechu, I., Pacheco, C., Ortiz Reyes, R.M., Chuecas, F., and Mas Bermejo, P.I.

(2019). Therapeutic vaccines for advanced non-small cell lung cancer. Cochrane

Database Syst. Rev. CD013377. https://doi.org/10.1002/14651858.CD013377.

eCollection 2019.

109. Losanno, T., and Gridelli, C. (2017). Recent advances in targeted advanced lung can-

cer therapy in the elderly. Expert Rev. Anticancer Ther. 17, 787–797.

110. Cáceres-Lavernia, H.H., Nenínger-Vinageras, E., Varona-Rodríguez, L.M., Olivares-

Romero, Y.A., Sánchez-Rojas, I., Mazorra-Herrera, Z., Basanta-Bergolla, D.,

Duvergel-Calderín, D., Torres-Cuevas, B.L., and Castillo-Carrillo, C. (2021).

Molecular Therapy: Oncology Vol. 32 March 2024 27

www.moleculartherapy.org

Review

Racotumomab in Non-Small Cell Lung Cancer as Maintenance and Second-Line

Treatment. MEDICC Rev. 23,21–28.

111. Stevens, D., Ingels, J., Van Lint, S., Vandekerckhove, B., and Vermaelen, K. (2020).

Dendritic Cell-Based Immunotherapy in Lung Cancer. Front. Immunol. 11, 620374.

112. Osmani, L., Askin, F., Gabrielson, E., and Li, Q.K. (2018). Current WHO guidelines

and the critical role of immunohistochemical markers in the subclassiﬁcation of

non-small cell lung carcinoma (NSCLC): Moving from targeted therapy to immu-

notherapy. Semin. Cancer Biol. 52, 103–109.

113. Hirsch, F.R., Scagliotti, G.V., Mulshine, J.L., Kwon, R., Curran, W.J., Jr., Wu, Y.L.,

and Paz-Ares, L. (2017). Lung cancer: current therapies and new targeted treat-

ments. Lancet 389, 299–311.

114. Raso, M.G., Bota-Rabassedas, N., and Wistuba, I.I. (2021). Pathology and

Classiﬁcation of SCLC. Cancers 13, 820.

115. Korde, R., Veluswamy, R., Allaire, J.C., and Barnes, G. (2022). Small cell lung cancer

patients treated with immune checkpoint inhibitor: a systematic lit erature review of

treatment efﬁcacy, safety and quality of life. Curr. Med. Res. Opin. 38, 1361–1368.

116. Maroun, J., Muñoz-Alía, M., Ammayappan, A., Schulze, A., Peng, K.W., and Russell,

S. (2017). Designing and building oncolytic viruses. Future Virol. 12, 193–213.

117. Seymour, L.W., and Fisher, K.D. (2016). Oncolytic viruses: ﬁnally delivering. Br. J.

Cancer 114, 357–361.

118. Kaufman, H.L., and Maciorowski, D. (2021). Advancing oncolytic virus therapy by

understanding the biology. Nat. Rev. Clin. Oncol.

119. Yang, Y., Xu, H., Shen, J., Yang, Y., Wu, S., Xiao, J., Xu, Y., Liu, X.Y., and Chu, L.

(2015). RGD-modiﬁded oncolytic adenovirus exhibited potent cytotoxic effect on

CAR-negative bladder cancer-initiating cells. Cell Death Dis. 6, e1760.

120. Martuza, R.L. (2000). Conditionally replicating herpes vectors for cancer therapy.

J. Clin. Invest. 105, 841–846.

121. Jahan, N., Ghouse, S.M., Martuza, R.L., and Rabkin, S.D. (2021). Situ Cancer

Vaccination and Immunovirotherapy Using Oncolytic HSV. Viruses 13.

122. Goldsmith, K., Chen, W., Johnson, D.C., and Hendricks, R.L. (1998). Infected cell

protein (ICP)47 enhances herpes simplex virus neurovirulence by blocking the

CD8+ T cell response. J. Exp. Med. 187, 341–348.

123. Chang, H.W., and Jacobs, B.L. (1993). Identiﬁcation of a conserved motif that is

necessary for binding of the vaccinia virus E3L gene products to double-stranded

RNA. Virology 194, 537–547.

124. Carroll, K., Elroy-Stein, O., Moss, B., and Jagus, R. (1993). Recombinant vaccinia vi-

rus K3L gene product prevents activation of double-stranded RNA-dependent, initi-

ation factor 2 alpha-speciﬁc protein kinase. J. Biol. Chem. 268, 12837–12842.

125. Kotwal, G.J., Isaacs, S.N., McKenzie, R., Frank, M.M., and Moss, B. (1990).

Inhibition of the complement cascade by the major secretory protein of vaccinia vi-

rus. Science 250, 827–830.

126. Herrera, E., Lorenzo, M.M., Blasco, R., and Isaacs, S.N. (1998). Functional analysis of

vaccinia virus B5R protein: essential role in virus envelopment is independent of a

large portion of the extracellular domain. J. Virol. 72, 294–302.

127. Buller, R.M., Smith, G.L., Cremer, K., Notkins, A.L., and Moss, B. (1985). Decreased

virulence of recombinant vaccinia virus expression vectors is associated with a

thymidine kinase-negative phenotype. Nature 317, 813–815.

128. McCart, J.A., Ward, J.M., Lee, J., Hu, Y., Alexander, H.R., Libutti, S.K., Moss, B., and

Bartlett, D.L. (2001). Systemic cancer therapy with a tumor-selective vaccinia virus

mutant lacking thymidine kinase and vaccinia growth factor genes. Cancer Res. 61,

8751–8757.

129. Norman, K.L., Hirasawa, K., Yang, A.D., Shields, M.A., and Lee, P.W.K. (2004).

Reovirus oncolysis: the Ras/RalGEF/p38 pathway dictates host cell permissiveness

to reovirus infection. Proc. Natl. Acad. Sci. USA 101, 11099–11104.

130. Lorence, R.M., Roberts, M.S., O’Neil, J.D., Groene, W.S., Miller, J.A., Mueller, S.N.,

and Bamat, M.K. (2007). Phase 1 clinical experience using intravenous administra-

tion of PV701, an oncolytic Newcastle disease virus. Curr. Cancer Drug Targets 7,

157–167.

131. Hotte, S.J., Lorence, R.M., Hirte, H.W., Polawski, S.R., Bamat, M.K., O’Neil, J.D.,

Roberts, M.S., Groene, W.S., and Major, P.P. (2007). An optimized clinical regimen

for the oncolytic virus PV701. Clin. Cancer Res. 13, 977–985.

132. Csatary, L.K., Gosztonyi, G., Szeberenyi, J., Fabian, Z., Liszka, V., Bodey, B., and

Csatary, C.M. (2004). MTH-68/H oncolytic viral treatment in human high-grade

gliomas. J. Neuro Oncol. 67,83–93.

133. Yu, Y.A., Shabahang, S., Timiryasova, T.M., Zhang, Q., Beltz, R., Gentschev, I.,

Goebel, W., and Szalay, A.A. (2004). Visualization of tumors and metastases in

live animals with bacteria and vaccinia virus encoding light-emitting proteins.

Nat. Biotechnol. 22, 313–320.

134. Power, A.T., and Bell, J.C. (2008). Taming the Trojan horse: optimizing dynamic

carrier cell/oncolytic virus systems for cancer biotherapy. Gene Ther. 15, 772–779.

135. Howard, F., and Muthana, M. (2020). Designer nanocarriers for navigating the sys-

temic delivery of oncolytic viruses. Nanomedicine 15,93–110.

136. Rosewell Shaw, A., and Suzuki, M. (2018). Oncolytic Viruses Partner With T-Cell

Therapy for Solid Tumor Treatment. Front. Immunol. 9, 2103.

137. Phan, M., Watson, M.F., Alain, T., and Diallo, J.S. (2018). Oncolytic Viruses on

Drugs: Achieving Higher Therapeutic Efﬁcacy. ACS Infect. Dis. 4, 1448–1467.

138. Hwang, C.C., Igase, M., Sakurai, M., Haraguchi, T., Tani, K., Itamoto, K.,

Shimokawa, T., Nakaichi, M., Nemoto, Y., Noguchi, S., et al. (2018). Oncolytic

reovirus therapy: Pilot study in dogs with spontaneously occurring tumours. Vet.

Comp. Oncol. 16, 229–238.

139. Mok, D.Z.L., and Chan, K.R. (2020). The Effects of Pre-Existing Antibodies on Live-

Attenuated Viral Vaccines. Viruses 12.

140. Seyoum, M., Enawgaw, B., and Melku, M. (2018). Human blood platelets and vi-

ruses: defense mechanism and role in the removal of viral pathogens. Thromb. J.

16, 16.

141. Harrington, K., Freeman, D.J., Kelly, B., Harper, J., and Soria, J.-C. (2019).

Optimizing oncolytic virotherapy in cancer treatment. Nat. Rev. Drug Discov. 18,

689–706.

142. Lemos de Matos, A., Franco, L.S., and McFadden, G. (2020). Oncolytic Viruses and

the Immune System: The Dynamic Duo. Molecular therapy. Mol. Ther. Methods

Clin. Dev. 17, 349–358.

143. Everts, A., Bergeman, M., McFadden, G., and Kemp, V. (2020). Simultaneous

Tumor and Stroma Targeting by Oncolytic Viruses. Biomedicines 8, 474.

144. Choi, A.H., O’Leary, M.P., Fong, Y., and Chen, N.G. (2016). From Benchtop to

Bedside: A Review of Oncolytic Virotherapy. Biomedicines 4.

145. Rahman, M.M., and McFadden, G. (2021). Oncolytic Viruses: Newest Frontier for

Cancer Immunotherapy. Cancers 13, 5452.

146. Cary, Z.D., Willingham, M.C., and Lyles, D.S. (2011). Oncolytic vesicular stomatitis

virus induces apoptosis in U87 glioblastoma cells by a type II death receptor mech-

anism and induces cell death and tumor clearance in vivo. J. Virol. 85, 5708–5717.

147. Ghiringhelli, F., Apetoh, L., Tesniere, A., Aymeric, L., Ma, Y., Ortiz, C., Vermaelen,

K., Panaretakis, T., Mignot, G., Ullrich, E., et al. (2009). Activation of the NLRP3

inﬂammasome in dendritic cells induces IL-1beta-dependent adaptive immunity

against tumors. Nat. Med. 15, 1170–1178.

148. Engeland, C.E., and Bell, J.C. (2020). Introduction to Oncolytic Virotherapy.

Methods Mol. Biol. 2058,1–6.

149. Jiang, H., and Fueyo, J. (2014). Healing after death: antitumor immunity induced by

oncolytic adenoviral therapy. OncoImmunology 3, e947872.

150. Breitbach, C.J., Paterson, J.M., Lemay, C.G., Falls, T.J., McGuire, A., Parato, K.A.,

Stojdl, D.F., Daneshmand, M., Speth, K., Kirn, D., et al. (2007). Targeted inﬂamma-

tion during oncolytic virus therapy severely compromises tumor blood ﬂow. Mol.

Ther. 15, 1686–1693.

151. Pearl, T.M., Markert, J.M., Cassady, K.A., and Ghonime, M.G. (2019). Oncolytic

Virus-Based Cytokine Expression to Improve Immune Activity in Brain and Solid

Tumors. Mol. Ther. Oncolytics 13,14–21.

152. Nguyen, H.-M.,Guz-Montgomery, K., and Saha, D. (2020). Oncolytic VirusEncoding

a Master Pro-InﬂammatoryCytokine Interleukin 12 in Cancer Immunotherapy.Cells

9, 400.

153. Kaufman, H.L., Kim, D.W., DeRaffele, G., Mitcham, J., Cofﬁn, R.S., and Kim-

Schulze, S. (2010). Local and distant immunity induced by intralesional vaccination

with an oncolytic herpes virus encoding GM-CSF in patients with stage IIIc and IV

melanoma. Ann. Surg Oncol. 17, 718–730.

28 Molecular Therapy: Oncology Vol. 32 March 2024

www.moleculartherapy.org

Review

154. Hu, H., Qiu, Y., Guo, M., Huang, Y., Fang, L., Peng, Z., Ji, W., Xu, Y., Shen, S., Yan,

Y., et al. (2015). Targeted Hsp70 expression combined with CIK-activated immune

reconstruction synergistically exerts antitumor efﬁcacy in patient-derived hepato-

cellular carcinoma xenograft mouse models. Oncotarget 6, 1079–1089.

155. Wang, R., Chen, J., Wang, W., Zhao, Z., Wang, H., Liu, S., Li, F., Wan, Y., Yin, J.,

Wang, R., et al. (2022). CD40L-armed oncolytic herpes simplex virus suppresses

pancreatic ductal adenocarcinoma by facilitating the tumor microenvironment

favorable to cytotoxic T cell response in the syngeneic mouse model. J.

Immunother. Cancer 10, e003809.

156. Ilkow, C.S., Marguerie, M., Batenchuk, C., Mayer, J., Ben Neriah, D., Cousineau, S.,

Falls, T., Jennings, V.A., Boileau, M., Bellamy, D., et al. (2015). Reciprocal cellular

cross-talk within the tumor microenvironment promotes oncolytic virus activity.

Nat. Med. 21, 530–536.

157. Toro Bejarano, M., and Merchan, J.R. (2015). Targeting tumor vasculature through

oncolytic virotherapy: recent advances. Oncolytic Virother. 4, 169–181.

158. Arulanandam, R., Batenchuk, C., Angarita, F.A., Ottolino-Perry, K., Cousineau, S.,

Mottashed, A., Burgess, E., Falls, T.J., De Silva, N., Tsang, J., et al. (2015).

VEGF-Mediated Induction of PRD1-BF1/Blimp1 Expression Sensitizes Tumor

Vasculature to Oncolytic Virus Infection. Cancer Cell 28, 210–224.

159. Gao, P., Ding, G., and Wang, L. (2021). The efﬁcacy and safety of oncolytic viruses in

the treatment of intermediate to advanced solid tumors: a systematic review and

meta-analysis. Transl. Cancer Res. 10, 4290–4302.

160. Martin, N., and Sattentau, Q. (2009). Cell-to-cell HIV-1 spread and its implications

for immune evasion. Curr. Opin. HIV AIDS 4, 143–149.

161. Melzer, M.K., Zeitlinger, L., Mall, S., Steiger, K., Schmid, R.M., Ebert, O.,

Krackhardt, A., and Altomonte, J. (2019). Enhanced Safety and Efﬁcacy of

Oncolytic VSV Therapy by Combination with T Cell Receptor Transgenic T Cells

as Carriers. Mol. Ther. Oncolytics 12,26–40.

162. Na, Y., Nam, J.P., Hong, J., Oh, E., Shin, H.C., Kim, H.S., Kim, S.W., and Yun, C.O.

(2019). Systemic administration of human mesenchymal stromal cells infected with

polymer-coated oncolytic adenovirus induces efﬁcient pancreatic tumor homing

and inﬁltration. J. Control. Release 305,75–88.

163. Yoon, A.R., Rivera-Cruz, C., Gimble, J.M., Yun, C.O., and Figueiredo, M.L. (2022).

Immunotherapy by mesenchymal stromal cell delivery of oncolytic viruses for treat-

ing metastatic tumors. Mol. Ther. Oncolytics 25,78–97.

164. Spaeth, E., Klopp, A., Dembinski, J., Andreeff, M., and Marini, F. (2008).

Inﬂammation and tumor microenvironments: deﬁning the migratory itinerary of

mesenchymal stem cells. Gene Ther. 15, 730–738.

165. Jazowiecka-Rakus, J., Sochanik, A., Rusin, A., Hadry

s, A., Fidyk, W., Villa, N.,

Rahman, M.M., Chmielik, E., Franco, L.S., and McFadden, G. (2020). Myxoma vi-

rus-loaded mesenchymal stem cells in experimental oncolytic therapy of murine

pulmonary melanoma. Mol. Ther. Oncolytics 18, 335–350.

166. Fischer, U.M., Harting, M.T., Jimenez, F., Monzon-Posadas, W.O., Xue, H., Savitz,

S.I., Laine, G.A., and Cox, C.S., Jr. (2009). Pulmonary passage is a major obstacle for

intravenous stem cell delivery: the pulmonary ﬁrst-pass effect. Stem Cells Dev. 18,

683–692.

167. Leoni, V., Gatta, V., Palladini, A., Nicoletti, G., Ranieri, D., Dall’Ora, M., Grosso, V.,

Rossi, M., Alviano, F., Bonsi, L., et al. (2015). Systemic delivery of HER2-retargeted

oncolytic-HSV by mesenchymal stromal cells protects from lung and brain metas-

tases. Oncotarget 6, 34774–34787.

168. Wang, H., Alarcón, C.N., Liu, B., Watson, F., Searles, S., Lee, C.K., Keys, J., Pi, W.,

Allen, D., Lammerding, J., et al. (2022). Genetically engineered and enucleated hu-

man mesenchymal stromal cells for the targeted delivery of therapeutics to diseased

tissue. Nat. Biomed. Eng. 6,882–897.

169. Reale, A., Calistri, A., and Altomonte, J. (2021). Giving Oncolytic Viruses a Free

Ride: Carrier Cells for Oncolytic Virotherapy. Pharmaceutics 13, 2192.

170. Reale, A., Krutzke, L., Cadamuro, M., Vitiello, A., von Einem, J., Kochanek, S., Pal

G., Parolin, C., and Calistri, A. (2023). Human Monocytes Are Suitable Carriers for

the Delivery of Oncolytic Herpes Simplex Virus Type 1 In Vitro and in a Chicken

Embryo Chorioallantoic Membrane Model of Cancer. Int. J. Mol. Sci. 24, 9255.

171. Eisenstein, S., Chen, S.H., and Pan, P.Y. (2014). Immune cells: more than simple car-

riers for systemic delivery of oncolytic viruses. Oncolytic Virother. 3,83–91.

172. Thorne, S.H., and Contag, C.H. (2008). Integrating the biological characteristics of

oncolytic viruses and immune cells can optimize therapeutic beneﬁts of cell-based

delivery. Gene Ther. 15, 753–758.

173. Kim, Y., Clements, D.R., Sterea, A.M., Jang, H.W., Gujar, S.A., and Lee, P.W.K.

(2015). Dendritic Cells in Oncolytic Virus-Based Anti-Cancer Therapy. Viruses 7,

6506–6525.

174. Ghasemi, M., Abbasi, L., Ghanbari Naeini, L., Kokabian, P., Nameh Goshay Fard,

N., and Givtaj, N. (2022). Dendritic cells and natural killer cells: The road to a suc-

cessful oncolytic virotherapy. Front. Immunol. 13, 950079.

175. Ilett, E.J., Bárcena, M., Errington-Mais, F., Grifﬁn, S., Harrington, K.J., Pandha, H.S.,

Coffey, M., Selby, P.J., Limpens, R.W.A.L., Mommaas, M., et al. (2011).

Internalization of oncolytic reovirus by human dendritic cell carriers protects the vi-

rus from neutralization. Clin. Cancer Res. 17, 2767–2776.

176. Lin, Y., Weisdorf, D.J., Solovey, A., and Hebbel, R.P. (2000). Origins of circulating

endothelial cells and endothelial outgrowth from blood. J. Clin. Invest. 105,71–77.

177. Dudek, A.Z., Bodempudi, V., Welsh, B.W., Jasinski, P., Grifﬁn, R.J., Milbauer, L.,

and Hebbel, R.P. (2007). Systemic inhibition of tumour angiogenesis by endothelial

cell-based gene therapy. Br. J. Cancer 97, 513–522.

178. Power, A.T., and Bell, J.C. (2007). Cell-based delivery of oncolytic viruses: a new

strategic alliance for a biological strike against cancer. Mol. Ther. 15, 660–665.

179. Liu, C., Russell, S.J., and Peng, K.W. (2010). Systemic therapy of disseminated

myeloma in passively immunized mice using measles virus-infected cell carriers.

Mol. Ther. 18, 1155–1164.

180. Lemay, C.G., Rintoul, J.L., Kus, A., Paterson, J.M., Garcia, V., Falls, T.J., Ferreira, L.,

Bridle, B.W., Conrad, D.P., Tang, V.A., et al. (2012). Harnessing oncolytic virus-

mediated antitumor immunity in an infected cell vaccine. Mol. Ther. 20, 1791–1799.

181. Chen, S.R., Chen, M.M., Ene, C., Lang, F.F., and Kan, P. (2022). Perfusion-guided

endovascular super-selective intra-arterial infusion for treatment of malignant brain

tumors. J. Neurointerv. Surg. 14, 533–538.

182. Ekeke, C.N., Russell, K.L., Murthy, P., Guo, Z.S., Soloff, A.C., Weber, D., Pan, W.,

Lotze, M.T., and Dhupar, R. (2022). Intrapleural interleukin-2-expressing oncolytic

virotherapy enhances acute antitumor effects and T-cell receptor diversity in malig-

nant pleural disease. J. Thorac. Cardiovasc. Surg. 163, e313–e328.

183. Morein, D., Erlichman, N., and Ben-Baruch, A. (2020). Beyond Cell Motility: The

Expanding Roles of Chemokines and Their Receptors in Malignancy. Front.

Immunol. 11, 952.

184. Rahman, M.M., and McFadden, G. (2020). Oncolytic Virotherapy with Myxoma

Virus. J. Clin. Med. 9, 171.

185. VanSeggelen, H., Tantalo, D.G., Afsahi, A., Hammill, J.A., and Bramson, J.L. (2015).

Chimeric antigen receptor-engineered T cells as oncolytic virus carriers. Mol. Ther.

Oncolytics 2, 15014.

186. Santos, J., Heiniö, C.,Quixabeira, D., Zafar, S., Clubb, J., Pakola,S., Cervera-Carrascon,

V., Havunen, R., Kanerva, A.,and Hemminki, A.(2021). SystemicDelivery of Oncolytic

Adenovirus to Tumors Using Tumor-Inﬁltrating Lymphocytes as Carriers. Cells

10,978.

187. Benencia, F., Courreges, M.C., Conejo-García, J.R., Buckanovich, R.J., Zhang, L.,

Carroll, R.H., Morgan, M.A., and Coukos, G. (2005). Oncolytic HSV exerts direct

antiangiogenic activity in ovarian carcinoma. Hum. Gene Ther. 16, 765–778.

188. Breitbach, C.J., Burke, J., Jonker, D., Stephenson, J., Haas, A.R., Chow, L.Q.M.,

Nieva, J., Hwang, T.H., Moon, A., Patt, R., et al. (2011). Intravenous delivery of a

multi-mechanistic cancer-targeted oncolytic poxvirus in humans. Nature 477,

99–102.

189. Sarkar, D., Spencer, J.A., Phillips, J.A., Zhao, W., Schafer, S., Spelke, D.P.,

Mortensen, L.J., Ruiz, J.P., Vemula, P.K., Sridharan, R., et al. (2011). Engineered

cell homing. Blood 118, e184–e191.

190. Sarkar, D., Vemula, P.K., Teo, G.S.L., Spelke, D., Karnik, R., Wee, L.Y., and Karp,

J.M. (2008). Chemical engineering of mesenchymal stem cells to induce a cell rolling

response. Bioconjug. Chem. 19, 2105–2109.

191. Levy, O., Zhao, W., Mortensen, L.J., Leblanc, S., Tsang, K., Fu, M., Phillips, J.A.,

Sagar, V., Anandakumaran, P., Ngai, J., et al. (2013). mRNA-engineered mesen-

chymal stem cells for targeted delivery of interleukin-10 to sites of inﬂammation.

Blood 122, e23–e32.

Molecular Therapy: Oncology Vol. 32 March 2024 29

www.moleculartherapy.org

Review

192. Liao, W., Pham, V., Liu, L., Riazifar, M., Pone, E.J., Zhang, S.X., Ma, F., Lu, M.,

Walsh, C.M., and Zhao, W. (2016). Mesenchymal stem cells engineered to express

selectin ligands and IL-10 exert enhanced therapeutic efﬁcacy in murine experi-

mental autoimmune encephalomyelitis. Biomaterials 77,87–97.

193. Muthana, M., Scott, S.D., Farrow, N., Morrow, F., Murdoch, C., Grubb, S., Brown,

N., Dobson, J., and Lewis, C.E. (2008). A novel magnetic approach to enhance the

efﬁcacy of cell-based gene therapies. Gene Ther. 15, 902–910.

194. Wahajuddin, A.S., and Arora, S. (2012). Superparamagnetic iron oxide nanopar-

ticles: magnetic nanoplatforms as drug carriers. Int. J. Nanomedicine 7, 3445–3471.

195. Fattahi, H., Laurent, S., Liu, F., Arsalani, N., Vander Elst, L., and Muller, R.N. (2011).

Magnetoliposomes as multimodal contrast agents for molecular imaging and cancer

nanotheragnostics. Nanomedicine (Lond) 6, 529–544.

196. Hennessy, M.L., Bommareddy, P.K., Boland, G., and Kaufman, H.L. (2019).

Oncolytic Immunotherapy. Surg. Oncol. Clin. N. Am. 28, 419–430.

197. Pyo, K.H., Kim, J.H., Lee, J.M., Kim, S.E., Cho, J.S., Lim, S.M., and Cho, B.C. (2019).

Promising preclinical platform for evaluation of immuno-oncology drugs using Hu-

PBL-NSG lung cancer models. Lung Cancer 127, 112–121.

198. Guil-Luna, S., Sedlik, C., and Piaggio, E. (2021). Humanized Mouse Models to

Evaluate Cancer Immunotherapeutics. Annu. Rev. Cancer Biol. 5,119–136.

199. Zeng, Y., Liu, B., Rubio, M.-T., Wang, X., Ojcius, D.M., Tang, R., Durrbach, A., Ru,

Z., Zhou, Y., and Lone, Y.-C. (2017). Creation of an immunodeﬁcient HLA-trans-

genic mouse (HUMAMICE) and functional validation of human immunity after

transfer of HLA-matched human cells. PLoS One 12, e0173754.

200. Shi, Z.-D., Pang, K., Wu, Z.-X., Dong, Y., Hao, L., Qin, J.-X., Wang, W., Chen, Z.-S.,

and Han, C.-H. (2023). Tumor cell plasticity in targeted therapy-induced resistance:

mechanisms and new strategies. Signal Transduct. Target. Ther. 8, 113.

201. Miles, L.A., Burga, L.N., Gardner, E.E., Bostina, M., Poirier, J.T., and Rudin, C.M.

(2017). Anthrax toxin receptor 1 is the cellular receptor for Seneca Valley virus.

J. Clin. Invest. 127, 2957–2967.

202. Caeser, R., Egger, J.V., Chavan, S., Socci, N.D., Jones, C.B., Kombak, F.E., Asher, M.,

Roehrl, M.H., Shah, N.S., Allaj, V., et al. (2022). Genomic and transcriptomic anal-

ysis of a library of small cell lung cancer patient-derived xenografts. Nat. Commun.

13, 2144.

203. Yu, X.-Y., Jin, X., and Shou, Z.-X. (2021). Surface-engineered smart nanocarrier-

based inhalation formulations for targeted lung cancer chemotherapy: a review of

current practices. Drug Deliv. 28, 1995–2010.

204. Sun, L., Liu, H., Ye, Y., Lei, Y., Islam, R., Tan, S., Tong, R., Miao, Y.-B., and Cai, L.

(2023). Smart nanoparticles for cancer therapy. Signal Transduct. Target. Ther.

8, 418.

205. Gandhi, L., Rodríguez-Abreu, D., Gadgeel, S., Esteban, E., Felip, E., De Angelis, F.,

Domine, M., Clingan, P., Hochmair, M.J., Powell, S.F., et al. (2018). Pembrolizumab

plus Chemotherapy in Metastatic Non–Small-Cell Lung Cancer. N. Engl. J. Med.

378, 2078–2092.

206. Liu, X., Zhang, J., Feng, K., Wang, S., Chen, L., Niu, S., Lu, Q., and Fang, Y. (2022).

Efﬁcacy and safety of oncolytic virus combined with chemotherapy or immune

checkpoint inhibitors in solid tumor patients: A meta-analysis. Front. Pharmacol. 13.

207. Schoenfeld, J., Jinushi, M., Nakazaki, Y., Wiener, D., Park, J., Soiffer, R., Neuberg, D.,

Mihm, M., Hodi, F.S., and Dranoff, G. (2010). Active immunotherapy induces anti-

body responses that target tumor angiogenesis. Cancer Res. 70, 10150–10160.

208. Wu, X., Giobbie-Hurder, A., Connolly, E.M., Li, J., Liao, X., Severgnini, M., Zhou, J.,

Rodig, S., and Hodi, F.S. (2018). Anti-CTLA-4 based therapy elicits humoral immu-

nity to galectin-3 in patients with metastatic melanoma. OncoImmunology 7,

e1440930.

209. Helmink, B.A., Reddy, S.M., Gao, J., Zhang, S., Basar, R., Thakur, R., Yizhak, K.,

Sade-Feldman, M., Blando, J., Han, G., et al. (2020). B cells and tertiary lymphoid

structures promote immunotherapy response. Nature 577, 549–555.

210. Cabrita, R., Lauss, M., Sanna, A., Donia, M., Skaarup Larsen, M., Mitra, S.,

Johansson, I., Phung, B., Harbst, K., Vallon-Christersson, J., et al. (2020). Tertiary

lymphoid structures improve immunotherapy and survival in melanoma. Nature

577,561–565.

211. He, J., Munir, F., Ragoonanan, D., Zaky, W., Khazal, S.J., Tewari, P., Fueyo, J.,

Gomez-Manzano, C., and Jiang, H. (2023). Combining CAR T Cell Therapy and

Oncolytic Virotherapy for Pediatric Solid Tumors: A Promising Option. Immuno

3,37–56.

212. Park, A.K., Fong, Y., Kim, S.-I., Yang, J., Murad, J.P., Lu, J., Jeang, B., Chang, W.-C.,

Chen, N.G., Thomas, S.H., et al. (2020). Effective combination immunotherapy us-

ing oncolytic viruses to deliver CAR targets to solid tumors. Sci. Transl. Med. 12,

eaaz1863.

213. Porter, C.E., Rosewell Shaw, A., Jung, Y., Yip, T., Castro, P.D., Sandulache, V.C.,

Sikora, A., Gottschalk, S., Ittman, M.M., Brenner, M.K., and Suzuki, M. (2020).

Oncolytic Adenovirus Armed with BiTE, Cytokine, and Checkpoint Inhibitor

Enables CAR T Cells to Control the Growth of Heterogeneous Tumors. Mol.

Ther. 28, 1251–1262.

214. Breitbach, C.J., De Silva, N.S., Falls, T.J., Aladl, U., Evgin, L., Paterson, J., Sun, Y.Y.,

Roy, D.G., Rintoul, J.L., Daneshmand, M., et al. (2011). Targeting Tumor

Vasculature With an Oncolytic Virus. Mol. Ther. 19, 886–894.

215. Evgin, L., Kottke, T., Tonne, J., Thompson, J., Huff, A.L., van Vloten, J., Moore, M.,

Michael, J., Driscoll, C., Pulido, J., et al. (2022). Oncolytic virus-mediated expansion

of dual-speciﬁc CAR T cells improves efﬁcacy against solid tumors in mice. Sci.

Transl. Med. 14, eabn2231.

216. Shi, Y., Hu, G., Su, J., Li, W., Chen, Q., Shou, P., Xu, C., Chen, X., Huang, Y., Zhu, Z.,

et al. (2010). Mesenchymal stem cells: a new strategy for immunosuppression and

tissue repair. Cell Res. 20, 510–518.

217. Mader, E.K., Maeyama, Y., Lin, Y., Butler, G.W., Russell, H.M., Galanis, E., Russell,

S.J., Dietz, A.B., and Peng, K.W. (2009). Mesenchymal stem cell carriers protect on-

colytic measles viruses from antibody neutralization in an orthotopic ovarian cancer

therapy model. Clin. Cancer Res. 15, 7246–7255.

218. Kim, J., Hall, R.R., Lesniak, M.S., and Ahmed, A.U. (2015). Stem Cell-Based Cell

Carrier for Targeted Oncolytic Virotherapy: Translational Opportunity and Open

Questions. Viruses 7, 6200–6217.

219. Cristi, F., Gutiérrez, T., Hitt, M.M., and Shmulevitz, M. (2022). Genetic

Modiﬁcations That Expand Oncolytic Virus Potency. Front. Mol. Biosci. 9, 831091.

220. Tian, Y., Xie, D., and Yang, L. (2022). Engineering strategies to enhance oncolytic

viruses in cancer immunotherapy. Signal Transduct. Target. Ther. 7, 117.

221. Yuan, M., Webb, E., Lemoine, N.R., and Wang, Y. (2016). CRISPR-Cas9 as a

Powerful Tool for Efﬁcient Creation of Oncolytic Viruses. Viruses 8, 72.

30 Molecular Therapy: Oncology Vol. 32 March 2024

www.moleculartherapy.org

Review

ResearchGate has not been able to resolve any citations for this publication.

Therapeutic vaccines for advanced non-small cell lung cancer

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Full-text available

Mar 2024

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It may result in little to no difference in the proportion of participants with at least one serious treatment-related adverse event, but the evidence is very uncertain (risk ratio (RR) 0.70, 95% CI 0.23 to 2.19; 2 studies, 362 participants; very low-certainty evidence). Epidermal growth factor vaccine Epidermal growth factor vaccine, compared to best supportive care as switch maintenance treatment after first-line chemotherapy, may result in little to no difference in overall survival (HR 0.82, 95% CI 0.66 to 1.02; 1 study, 378 participants; low-certainty evidence), and in the proportion of participants with at least one serious treatment-related adverse event (RR 1.32, 95% CI 0.88 to 1.98; 2 studies, 458 participants; low-certainty evidence). hTERT (vx-001) The hTERT (vx-001) vaccine compared to placebo as maintenance treatment after first-line chemotherapy may result in little to no difference in overall survival (HR 0.97, 95% CI 0.70 to 1.34; 1 study, 190 participants). 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Personalised peptide vaccine Personalised peptide vaccine plus docetaxel compared to docetaxel plus placebo post-chemotherapy treatment may result in little to no difference in overall survival (HR 0.80, 95% CI 0.42 to 1.52) and progression-free survival (HR 0.78, 95% CI 0.43 to 1.42). OSE2101 The OSE2101 vaccine compared with chemotherapy, after chemotherapy or immunotherapy, was assessed in one study with 219 participants. It may result in little to no difference in overall survival (HR 0.86, 95% CI 0.62 to 1.19). It may result in a small difference in the proportion of people with at least one serious treatment-related adverse event (RR 0.95, 95% CI 0.91 to 0.99). SRL172 The SRL172 vaccine of killed Mycobacterium vaccae, added to chemotherapy, compared to chemotherapy alone, may result in no difference in overall survival, and may increase the proportion of people with at least one serious treatment-related adverse event (RR 2.07, 95% CI 1.76 to 2.43; 351 participants). Authors' conclusions: Adding a vaccine resulted in no differences in overall survival, except for racotumomab, which showed some improvement compared to placebo, but the difference in median survival time was very small (1.4 months) and the study only included 176 participants. Regarding progression-free survival, we observed no differences between the compared treatments, except for TG4010, which may increase progression-free survival slightly. There were no differences between the compared treatments in serious treatment-related adverse events, except for SRL172 (killed Mycobacterium vaccae) added to chemotherapy, which was associated with an increase in the proportion of participants with at least one serious treatment-related adverse event, and OSE2101, which may decrease slightly the proportion of people having at least one serious treatment-related adverse event. 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Smart nanoparticles, which can respond to biological cues or be guided by them, are emerging as a promising drug delivery platform for precise cancer treatment. The field of oncology, nanotechnology, and biomedicine has witnessed rapid progress, leading to innovative developments in smart nanoparticles for safer and more effective cancer therapy. In this review, we will highlight recent advancements in smart nanoparticles, including polymeric nanoparticles, dendrimers, micelles, liposomes, protein nanoparticles, cell membrane nanoparticles, mesoporous silica nanoparticles, gold nanoparticles, iron oxide nanoparticles, quantum dots, carbon nanotubes, black phosphorus, MOF nanoparticles, and others. We will focus on their classification, structures, synthesis, and intelligent features. These smart nanoparticles possess the ability to respond to various external and internal stimuli, such as enzymes, pH, temperature, optics, and magnetism, making them intelligent systems. Additionally, this review will explore the latest studies on tumor targeting by functionalizing the surfaces of smart nanoparticles with tumor-specific ligands like antibodies, peptides, transferrin, and folic acid. We will also summarize different types of drug delivery options, including small molecules, peptides, proteins, nucleic acids, and even living cells, for their potential use in cancer therapy. While the potential of smart nanoparticles is promising, we will also acknowledge the challenges and clinical prospects associated with their use. Finally, we will propose a blueprint that involves the use of artificial intelligence-powered nanoparticles in cancer treatment applications. By harnessing the potential of smart nanoparticles, this review aims to usher in a new era of precise and personalized cancer therapy, providing patients with individualized treatment options.

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Full-text available

Jul 2023

Therapeutic strategies harnessing the immune system to eliminate tumour cells have been successfully used for several cancer types, including in patients with advanced-stage non-small-cell lung cancer (NSCLC). In these patients, immune-checkpoint inhibitors (ICIs) can provide durable responses and improve overall survival either as monotherapy, or combined with chemotherapy or other immunotherapeutic agents. However, the implementation of ICIs in early stage NSCLC has been hampered by the continuous struggle to develop robust end points to assess their efficacy in this setting, especially those enabling a fast and reproducible evaluation of the clinical activity of neoadjuvant strategies. Several trials are testing ICIs, alone or in combination with chemotherapy, in early stage NSCLC as an adjuvant, neoadjuvant or perioperative approach. As a novelty, most trials in the neoadjuvant setting have adopted pathological response as a primary end point. ICIs have been approved for use in the neoadjuvant and adjuvant settings on the basis of event-free survival and disease-free survival benefit, respectively; however, the correlation of these end points with overall survival remains unclear in these settings. Unresolved challenges for the optimal use of ICIs with curative intent include concerns about their applicability in daily clinical practice and about improving patient selection based on predictive biomarkers or assessment of pathological response and minimal residual disease. In this Review, we discuss the rationale, available strategies and current trial landscape for the implementation of ICIs in patients with resectable NSCLC, and we further elaborate on future approaches to optimize their clinical benefit.

Human Monocytes Are Suitable Carriers for the Delivery of Oncolytic Herpes Simplex Virus Type 1 In Vitro and in a Chicken Embryo Chorioallantoic Membrane Model of Cancer

Article

Full-text available

May 2023
INT J MOL SCI

Oncolytic viruses (OVs) are promising therapeutics for tumors with a poor prognosis. An OV based on herpes simplex virus type 1 (oHSV-1), talimogene laherparepvec (T-VEC), has been recently approved by the Food and Drug Administration (FDA) and by the European Medicines Agency (EMA) for the treatment of unresectable melanoma. T-VEC, like most OVs, is administered via intratumoral injection, underlining the unresolved problem of the systemic delivery of the oncolytic agent for the treatment of metastases and deep-seated tumors. To address this drawback, cells with a tropism for tumors can be loaded ex vivo with OVs and used as carriers for systemic oncolytic virotherapy. Here, we evaluated human monocytes as carrier cells for a prototype oHSV-1 with a similar genetic backbone as T-VEC. Many tumors specifically recruit monocytes from the bloodstream, and autologous monocytes can be obtained from peripheral blood. We demonstrate here that oHSV-1-loaded primary human monocytes migrated in vitro towards epithelial cancer cells of different origin. Moreover, human monocytic leukemia cells selectively delivered oHSV-1 to human head-and-neck xenograft tumors grown on the chorioallantoic membrane (CAM) of fertilized chicken eggs after intravascular injection. Thus, our work shows that monocytes are promising carriers for the delivery of oHSV-1s in vivo, deserving further investigation in animal models.

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Mar 2023

Despite the success of targeted therapies in cancer treatment, therapy-induced resistance remains a major obstacle to a complete cure. Tumor cells evade treatments and relapse via phenotypic switching driven by intrinsic or induced cell plasticity. Several reversible mechanisms have been proposed to circumvent tumor cell plasticity, including epigenetic modifications, regulation of transcription factors, activation or suppression of key signaling pathways, as well as modification of the tumor environment. Epithelial-to-mesenchymal transition, tumor cell and cancer stem cell formation also serve as roads towards tumor cell plasticity. Corresponding treatment strategies have recently been developed that either target plasticity-related mechanisms or employ combination treatments. In this review, we delineate the formation of tumor cell plasticity and its manipulation of tumor evasion from targeted therapy. We discuss the non-genetic mechanisms of targeted drug-induced tumor cell plasticity in various types of tumors and provide insights into the contribution of tumor cell plasticity to acquired drug resistance. New therapeutic strategies such as inhibition or reversal of tumor cell plasticity are also presented. We also discuss the multitude of clinical trials that are ongoing worldwide with the intention of improving clinical outcomes. These advances provide a direction for developing novel therapeutic strategies and combination therapy regimens that target tumor cell plasticity.

Combining CAR T Cell Therapy and Oncolytic Virotherapy for Pediatric Solid Tumors: A Promising Option

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Jan 2023

Despite advances in treatment options, the clinical outcomes of pediatric patients with advanced solid tumors have hardly improved in decades, and alternative treatment options are urgently needed. Innovative therapies, such as chimeric antigen receptor (CAR) T cells and oncolytic viruses (OVs), are currently being evaluated in both adults and children with refractory solid tumors. Because pediatric solid tumors are remarkably diverse and biologically different from their adult counterparts, more research is required to develop effective treatment regimens for these patients. Here, we first summarize recent efforts and advances in treatments for pediatric solid tumors. Next, we briefly introduce the principles for CAR T cell therapy and oncolytic virotherapy and clinical trials thereof in pediatric patients. Finally, we discuss the basis for the potential benefits of combining the two approaches in pediatric patients with advanced solid tumors.

Dendritic cells and natural killer cells: The road to a successful oncolytic virotherapy

Article

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Jan 2023

Every type of cancer tissue is theoretically more vulnerable to viral infection. This natural proclivity has been harnessed as a new anti-cancer therapy by employing oncolytic viruses (OVs) to selectively infect and destroy cancer cells while providing little or no harm with no toxicity to the host. Whereas the primary oncolytic capabilities of OVs initially sparked the greatest concern, the predominant focus of research is on the association between OVs and the host immune system. Numerous OVs are potent causal agents of class I MHC pathway-related chemicals, enabling early tumor/viral immune recognition and cytokine-mediated response. The modified OVs have been studied for their ability to bind to dendritic cells (DCs) by expressing growth factors, chemokines, cytokines, and defensins inside the viral genome. OVs, like reovirus, can directly infect DCs, causing them to release chemokines and cytokines that attract and excite natural killer (NK) cells. In addition, OVs can directly alter cancer cells’ sensitivity to NK by altering the expression levels of NK cell activators and inhibitors on cancerous cells. Therefore, NK cells and DCs in modulating the therapeutic response should be considered when developing and improving future OV-based therapeutics, whether modified to express transgenes or used in combination with other drugs/immunotherapies. Concerning the close relationship between NK cells and DCs in the potential of OVs to kill tumor cells, we explore how DCs and NK cells in tumor microenvironment affect oncolytic virotherapy and summarize additional information about the interaction mentioned above in detail in this work.

Efficacy and safety of oncolytic virus combined with chemotherapy or immune checkpoint inhibitors in solid tumor patients: A meta-analysis

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Full-text available

Nov 2022

Background: In recent years, several clinical trials have focused on oncolytic virus (OVs) combined with chemotherapy or immune checkpoint inhibitors (ICIs) in solid tumor patients, which showed encouraging effects. However, few studies have concentrated on the summary on the safety and efficacy of the combined treatments. Therefore, we conducted this meta-analysis to explore the safety and curative effect of the combined therapy. Methods: We searched the PubMed, Cochrane Library, Embase, and Clinicaltrials.gov databases to comprehensively select articles on OVs combined with chemotherapy or ICIs for the solid tumor treatment. Overall survival (OS), progression-free survival (PFS), 1-year survival rate, 2-year survival rate, objective response rate (ORR), and adverse events (AEs) were the outcomes. Results: Fifteen studies with 903 patients were included in this meta-analysis. The pooled ORR was 32% [95% confidence interval (CI): 27–36%, I² = 24.9%, p = 0.239]. Median OS and median PFS were 6.79 months (CI: 4.29–9.30, I² = 62.9%, p = 0.044) and 3.40 months (CI: 2.59–4.22, I² = 0.0%, p = 0.715), respectively. The 1-year survival rate was 38% (CI: 0.29–0.47, I² = 62.9%, p = 0.044), and the 2-year survival rate was 24% (CI: 12–37%, I² = 0.0%, p = 0.805). The most common AEs were fever (63%, CI: 57–69%, I² = 2.3%, p = 0.402), fatigue (58%, CI: 51–65%, I² = 49.2%, p = 0.096), chill (52%, CI: 43–60%, I² = 0.0%, p = 0.958), and neutropenia (53%, CI: 47–60%, I² = 0.0%, p = 0.944). Conclusion: OVs combined with ICIs showed a better efficacy than OVs combined with chemotherapy, which lends support to further clinical trials of OVs combined with ICIs. In addition, OVs combined with pembrolizumab can exert increased safety and efficacy. The toxicity of grades ≥3 should be carefully monitored and observed. However, high-quality, large-scale clinical trials should be completed to further confirm the efficacy and safety of OVs combined with ICIs. Systematic Review Registration: [https://www.crd.york.ac.uk/PROSPERO/login.php], identifier [RD42022348568].

Durable melanoma control following disseminated T-VEC herpetic infection

Article

Full-text available

Sep 2022

851 Voyager V1 (VV1) oncolytic virus combined with immune checkpoint therapy boosts CTL responses to multiple tumor antigens and correspondingly deepens tumor responses in murine models of melanoma, lung and colon cancer

Conference Paper

Nov 2022

Background There is a need for novel immunotherapies to address patient populations resistant or refractory to immune checkpoint inhibitors (CPI). VV1 is an oncolytic vesicular stomatitis virus engineered to express interferon beta (IFNβ) to enhance anti-tumor immune responses and tumor selectivity. Phase 1 studies demonstrated VV1 anti-tumor activity in certain clinical settings either alone or in combination with a CPI. The current preclinical study aimed to identify dosing and scheduling regimens that maximize the efficacy of VV1 in combination with CPIs. Methods Immune-competent mice bearing syngeneic tumor models MC38 (colorectal), B16F10 (melanoma) and CMT64 (lung adenocarcinoma) tumors were dosed to test combinations of VV1 delivered intravenously with anti-PD-1 and anti-CTLA4 antibodies. Treatment was started once tumors were established, and T cell responses in the tumor and peripheral lymphoid organs were analyzed using flow cytometry and ELISPOT assays. Results Potent anti-tumor efficacy was observed following intratumoral or intravenous administration of VV1 combined with anti-CTLA4 and anti-PD-1. A comparison of single dose versus repeat administration of anti-CTLA4 in combination with VV1 plus continuous anti-PD-1 showed that a single dose was sufficient to maximally enhance the depth and durability of tumor response. This effect was observed consistently in multiple tumor models, including anti-PD-1 sensitive (MC38) or anti-PD-1 resistant tumor models (B16F10 and CMT64). Remarkably, the triple combination boosted T cell priming against the B16F10 and CMT64 neo-antigen peptides in TILs and tumor-draining lymph nodes. ELISPOT and multimer staining showed that, in contrast to doublet therapy using virus and a single CPI, triplet combination therapy strongly boosted CTL responses against a broad array of B16F10 and CMT64 neoepitopes, detected both in the tumor and in tumor-draining lymph nodes. This was associated with increased infiltration of CD8 T cells in the tumor, but the number of regulatory T cells was not impacted, indicating that the enhancing effect of anti-CTLA4 was not a consequence of Treg depletion. Conclusions Intratumoral or intravenous VV1 virotherapy combined with anti-CTLA4 and anti-PD-1 checkpoint antibodies synergistically enhances tumor control in multiple syngeneic mouse tumor models. The triple combination seems to promote a tumor-vaccination effect, by inducing a polyclonal anti-tumor T cell response and boosting anti-tumor CTL responses. This triplet combination approach will soon be evaluated clinically in patients with advanced melanoma (after progression on an anti-PD1) and first line NSCLC patients. (ClinicalTrials.gov Identifier: NCT04291105).

Advances in Cell-Based Delivery of Oncolytic Viruses as Therapy for Lung Cancer

Abstract

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