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Advances and challenges in gene
therapy strategies for pediatric
cancer: a comprehensive update
Amir Kian Moaveni
1†
, Maryam Amiri
1
, Behrouz Shademan
2†
,
Arezoo Farhadi
3
, Javad Behroozi
4
and Alireza Nourazarian
5
*
1
Pediatric Urology and Regenerative Medicine Research Center, Tehran University of Medical Sciences,
Tehran, Iran,
2
Stem Cell Research Center, Tabriz University of Medical Sciences, Tabriz, Iran,
3
Department of Genetics and Molecular Medicine, School of Medicine, Zanjan University of Medical
Sciences, Zanjan, Iran,
4
Department of Cell and Molecular Biology, Faculty of Biological Sciences,
Kharazmi University, Tehran, Iran,
5
Department of Basic Medical Sciences, Khoy University of Medical
Sciences, Khoy, Iran
Pediatric cancers represent a tragic but also promising area for gene therapy.
Although conventional treatments have improved survival rates, there is still a need
for targeted and less toxic interventions. This article critically analyzes recent
advances in gene therapy for pediatric malignancies and discusses the
challenges that remain. We explore the innovative vectors and delivery systems
that have emerged, such as adeno-associated viruses and non-viral platforms,
which show promise in addressing the unique pathophysiology of pediatric tumors.
Specifically, we examine the field of chimeric antigen receptor (CAR) T-cell
therapies and their adaptation for solid tumors, which historically have been
more challenging to treat than hematologic malignancies. We also discuss the
genetic and epigenetic complexities inherent to pediatric cancers, such as tumor
heterogeneity and the dynamic tumor microenvironment, which pose significant
hurdles for gene therapy. Ethical considerations specific to pediatric populations,
including consent and long-term follow-up, are also analyzed. Additionally, we
scrutinize the translation of research from preclinical models that often fail to
mimic pediatric cancer biology to the regulatory landscapes that can either support
or hinder innovation. In summary, this article provides an up-to-date overview of
gene therapy in pediatric oncology, highlighting both the rapid scientificprogress
and the substantial obstacles that need to be addressed. Through this lens, we
propose a roadmap for future research that prioritizes the safety, efficacy, and
complex ethical considerations involved in treating pediatric patients. Our ultimate
goal is to move from incremental advancements to transformative therapies.
KEYWORDS
gene therapy, pediatric cancer, CRISPR-Cas9, gene editing, delivery systems
OPEN ACCESS
EDITED BY
Georgina Gonzalez-Avila,
National Institute of Respiratory Diseases-
Mexico (INER), Mexico
REVIEWED BY
Sameh A. Abdelnour,
Zagazig University, Egypt
Chao Chen,
Nanjing University of Chinese Medicine, China
*CORRESPONDENCE
Alireza Nourazarian,
noorazarian_a@khoyums.ac.ir
†
These authors have contributed equally to
this work
RECEIVED 05 February 2024
ACCEPTED 27 March 2024
PUBLISHED 21 May 2024
CITATION
Moaveni AK, Amiri M, Shademan B, Farhadi A,
Behroozi J and Nourazarian A (2024), Advances
and challenges in gene therapy strategies for
pediatric cancer: a comprehensive update.
Front. Mol. Biosci. 11:1382190.
doi: 10.3389/fmolb.2024.1382190
COPYRIGHT
© 2024 Moaveni, Amiri, Shademan, Farhadi,
Behroozi and Nourazarian. This is an open-
access article distributed under the terms of the
Creative Commons Attribution License (CC BY).
The use, distribution or reproduction in other
forums is permitted, provided the original
author(s) and the copyright owner(s) are
credited and that the original publication in this
journal is cited, in accordance with accepted
academic practice. No use, distribution or
reproduction is permitted which does not
comply with these terms.
Abbreviation: CAR, chimeric antigen receptor; ALL, acute lymphoblastic leukemia; CDKN, cyclin-
dependent kinase inhibitor; CRISPR, clustered regularly interspaced short palindromic repeats; SCID,
severe combined immune deficiency; ADA, adenosine deaminase; GOSH, Great Ormond Street
Hospital; GVHD, graft-vs-host disease; RNAi, RNA interference; ALK, anaplastic lymphoma kinase;
miRNAs, microRNAs; AAVs, adeno-associated viruses; LNPs, lipid nanoparticles; HIV, human
immunodeficiency virus; scFv, single-chain variable fragment; B-ALL, B-cell acute lymphoblastic
leukemia; CRS, cytokine release syndrome; HER2, human epidermal growth factor receptor 2; EGFR,
epidermal growth factor receptor; ADCC, antibody-dependent cellular cytotoxicity; CDC, complemen t-
dependent cytotoxicity; PD-1, programmed cell death protein 1; PD-L1, programmed death ligand 1;
CTLA-4, cytotoxic T-lymphocyte-associated antigen 4; irAEs, immune-related adverse events.
Frontiers in Molecular Biosciences frontiersin.org01
TYPE Review
PUBLISHED 21 May 2024
DOI 10.3389/fmolb.2024.1382190
1 Introduction
Despite being less common worldwide, childhood cancer
presents a unique set of challenges that differ from those of
adult cancers (Agrawal and Bansal, 2019). Approximately
400,000 children and adolescents ages 0–19 are diagnosed with
cancer annually (Organization, 2021). According to the World
Health Organization, childhood cancer survival rates vary widely
by geography. Children in high-income countries have a survival
rate of over 80%, while survival rates in many low- and middle-
income countries fall below 30% (Childhood Cancer, 2023). The
unique biological characteristics and age-dependent dynamics of
childhood cancer present significant barriers to detection,
diagnosis, and treatment. These barriers often lead to long-
lasting complications that can affect critical developmental
aspects, highlighting the need for therapeutic strategies that
optimize survival and mitigate adverse effects (Blattner-Johnson
et al., 2022).
The molecular basis of pediatric cancer differs from many adult
epithelial tumors, which exhibit high mutation rates in oncogenes
and tumor suppressors (Kirches et al., 2021). Pediatric cancers
generally have fewer mutations but a higher frequency of
chromosomal structural rearrangements resulting in oncogenic
gene fusions (Newman et al., 2021). An example is the ETV6-
RUNX1 fusion gene resulting from a t (Jones et al., 2019;Yahya
and Alqadhi, 2021) translocation that is associated with 25% of
pediatric B-cell acute lymphoblastic leukemia (ALL) cases, a fusion
gene that is absent in adult leukemias (Aydin et al., 2016). In the
field of oncology, researchers have discovered important genetic
alterations. One example is the t (Ruan et al., 2020;Martinez et al.,
2022) BCR-ABL1 fusion, which is often found in cases of acute
lymphoblastic leukemia (ALL) in children. Another example is the
t(Laetsch et al., 2021;Martinez et al., 2022)EWSR1-FLI1fusion,
which is frequently linked to Ewing sarcoma. These specific
chromosomal translocations play a vital role in the
development of these types of cancers (Sole et al., 2021). The
relative rarity of mutations may reflect the shorter time frame for
accumulation of genetic defects early in life (Ruan et al., 2020).
Nevertheless, certain consistent mutational hotspots are observed,
such as activating mutations in the RAS-MAPK pathway in
juvenile myelomonocytic leukemia (Kim et al., 2021). Table 1
shows the different types of pediatric cancers and their associated
genetic alterations.
The unique mutational landscape and cytogenetic abnormalities
of pediatric tumors provide excellent opportunities for targeted
therapy, particularly gene therapy (Laetsch et al., 2021). Gene
therapy—a promising approach to treating disease by altering the
genetic content of patients’cells—shows potential for greater
efficacy and specificity than traditional chemotherapy, especially
in pediatric cancers with identified genetic drivers (de Lartigue,
2018;Yahya and Alqadhi, 2021).
The immense potential of gene therapy in combating resistant
pediatric malignancies has been demonstrated in recent preclinical
studies and clinical trials (Campbell et al., 2020). For example,
chimeric antigen receptor (CAR) T-cell therapy has shown high
remission rates in relapsed B-cell ALL by modifying the patient’s
own T cells to recognize and eradicate cancer cells (Voynova and
Kovalovsky, 2021). Early phase trials of CAR T-cells have also shown
promising results in pediatric solid tumors (Vitanza et al., 2021).
Beyond immunotherapy, some studies have shown improved
outcomes by directly correcting single gene defects (Labrosse
et al., 2019).
However, as promising as gene therapy appears to be, it also
faces several challenges that hinder its widespread clinical adoption.
Efficient delivery to targeted tumor tissues, off-target genomic
alterations, and potential adverse immune responses are major
hurdles (Kirschner and Cathomen, 2020;Jeong et al., 2021). The
high costs of personalized cell therapies, complex manufacturing
requirements, and regulatory uncertainties regarding emerging
genetic technologies are additional considerations (Narayanan,
2016). Therefore, systematic research efforts are crucial to
address these limitations, improve safety profiles, demonstrate
efficacy through rigorous trials, and develop innovative strategies
for improved accessibility.
This review aims to provide a thorough assessment of the
current landscape and future prospects of gene therapy in
pediatric oncology. We will review the genetic mechanisms
underlying major childhood cancers and outline recent
preclinical and clinical advances in gene therapy for various
malignancies. We will also examine key challenges such as
delivery barriers, safety concerns, manufacturing issues, and
potential solutions. The advancement of gene therapy approaches
represents a significant opportunity to usher in an era of
personalized, targeted medicine that can dramatically improve
cure rates and quality of life for children with cancer worldwide.
To realize this potential paradigm shift, collaborative efforts across
research, medicine, industry, and government are needed to
systematically overcome the challenges that impede clinical
translation.
2 Overview of gene therapy in
pediatric cancer
A seismic shift in pediatric cancer treatment has occurred with
the advent of gene therapy. This medical revolution is based on the
principle of altering the genetic makeup of cells to treat or prevent
disease (Yahya and Alqadhi, 2021). Faulty genes can lead to the
development of pediatric cancers, hence the promising strategy of
using viral vectors to introduce functional copies (Hacker
et al., 2020).
Gene therapy facilitates the construction of tailored, targeted
therapies that depend on the unique genetic drivers of various
pediatric malignancies (Johnson, 2018). For example, the
introduction of tumor suppressor genes serves to counteract pro-
growth mutations (Gregory and Copple, 2023). Survival rates in
certain pediatric cancers have been significantly improved with gene
therapy compared to standard therapy alone, according to recent
studies (Hunger et al., 2012;Nowicki et al., 2016). Due to the lack of
mutations from environmental exposures, pediatric tumors are well-
suited for genetic approaches due to germline mutations (Kilburn
and Packer, 2020).
A variety of gene therapy strategies are currently being used in
pediatric oncology. These range from the correction of single gene
defects to the delivery of suicide genes that selectively kill cancer cells
(Das et al., 2015). Powerful gene-editing tools, such as clustered
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regularly interspaced short palindromic repeats (CRISPR)-Cas9,
allow for precision targeting but require rigorous safety testing
for off-target effects (Atkins et al., 2021;Guo et al., 2023). One
of the major challenges is to ensure precise delivery of the
therapeutic gene to cancer cells while preventing unintended
modifications (Chen et al., 2018). Other obstacles include
potential immunogenicity and regulation of the expression of the
introduced genes (Ziegler et al., 2018). The main gentherapy
metohds shown in Figure 1.
As gene therapy research continues to advance, the prospect
of more effective and less toxic treatments continues to grow
(Deverman et al., 2018). Despite existing challenges, gene
therapy has immense potential to usher in a new era of
personalized medicine for childhood cancer. Sustained
research will be essential to overcome current obstacles and
fully realize the innovative promise of genetic approaches. Major
milestones in gene therapy for childhood cancer are outlined
in Table 2.
TABLE 1 Overview of pediatric cancer types and their genetic alterations.
Cancer type Common genetic alterations Prevalence in pediatric population Reference
Brain tumors KIAA1549-BRAF, BRAFV600E, FGFR1 mut or
rearrangement, NF1, SMARCB1 (INI1), SMARCA4,
microRNA cluster C19MC amplification,
FOXR2 rearrangements, BCOR ITD, CTNNB1, DDX3X,
SMARCA4, TP53, PTCH1, SUFU, SMO, GLI2, and TP53
20%–25% of pediatric cancer Jones et al. (2019)
ALL CDKN2A/B deletion 15%–35% of pediatric patients with de novo ALL Martinez et al. (2022)
Retinoblastoma RB1 tumor-suppressor gene, polymorphisms in p53,
CDKN1A, and CDKN2A, genetic modifiers like MDM2,
MDM4, or MED4
Approximately 40% of all cases of retinoblastoma are
classified as hereditary, with the majority of those
individuals having tumors present in both eyes
Capasso et al. (2020)
Wilms tumor WT1, mutations in REST, CHEK2, and PALB2 Most (95%) of these tumors are diagnosed in children
under 10 years old
Treger et al. (2019)
Neuroblastoma ASCL1 and PHOX2B 8% of all malignancies in children Guan et al. (2021)
ALL, acute lymphoblastic leukemia; CDKN, cyclin-dependent kinase inhibitor.
FIGURE 1
Schematic diagram of gene delivery methods.
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2.1 Types of gene therapy approaches used
in pediatric cancer treatment
2.1.1 Gene replacement therapy
Gene replacement therapy has emerged as a central strategy in the
field of gene therapy and has shown great promise in the treatment of
certain pediatric cancers (Pearl et al., 2023). The thrust of this
approach is to identify a particular mutated gene in a tumor and
use viral vectors to deliver a normal,“wild type”version of that gene to
the cancer cells (Bhattacharjee et al., 2022). The goal of introducing a
functional copy of the aberrantly mutated gene is to normalize the
cancer’s genetics and limit its proliferation (Pscherer et al., 2006).
This therapy is particularly suitable for cancers driven by single-
gene mutations, such as the BCR-ABL1 translocations characteristic
of pediatric ALL (Sugapriya et al., 2012). However, there are
challenges in selecting the optimal vector for gene delivery.
While viruses could effectively infect human cells, they can
induce immune responses against the introduced gene,
potentially limiting efficacy (Aledo-Serrano et al., 2021). Another
challenge is to ensure sustained expression of the delivered gene.
Nevertheless, gene replacement therapy has been successful in
certain pediatric cancers. For example, in ALL, the introduction of
CAR genes into patients’T cells has resulted in high remission rates
in refractory disease (Wu et al., 2021). Early studies have shown
promising results in using gene replacement to correct mutated
MERTK genes in neuroblastoma. Vollrath et al. found that
administering recombinant adenovirus encoding MERTK
subretinally reversed the defect in retinal pigment epithelium
phagocytosis and rescued photoreceptors from degeneration in
juvenile rats. As a result, the treated areas in animal models,
which already exhibited significant pathology, appeared nearly
normal (Vollrath et al., 2001).
The potential of gene replacement therapy to restore
conventional function by targeting single genetic drivers
underscores its relevance for precision treatment of pediatric
malignancies (Senft et al., 2017). Expansion of this promising
approach will require refinement of gene delivery methods to
improve safety and efficacy, long-term outcome studies, and
expansion of trials across the spectrum of pediatric cancers
driven by targetable mutations (Magnani et al., 2013).
Overcoming existing barriers could pave the way for a new
generation of highly specific cancer therapies that could
potentially eradicate mutation-driven pediatric tumors.
2.1.2 Gene suppression therapy
Gene suppression therapy, often referred to as gene silencing,
symbolizes a breakthrough approach to gene therapy that aims to
combat disease by silencing harmful genes responsible for disease
development. This method of silencing deleterious genes appears
promising in the treatment of cancers activated by gain-of-function
mutations, particularly those associated with pediatric malignancies
(He and Jia, 2020).
RNA interference (RNAi), a powerful tool for gene silencing,
inhibits the translation of targeted mRNAs via complementary base
TABLE 2 Timeline of major milestones in gene therapy for pediatric cancer.
Year Milestone Description Reference
1990 First gene therapy clinical trial The first gene therapy clinical trial was conducted on a patient with a rare genetic
disease, marking the beginning of gene therapy research
Danaeifar (2022)
1992 Stem cells used as a vector to deliver therapeutic
genes
The goal of this first trial conducted by Bordignon et al. was to correct SCID
syndrome caused by a deficiency in ADA
Bordignon et al.
(1995)
2000 Two French patients with SCID experienced gene
therapy
Gene therapy has been successfully used by French researchers to treat SCID Dobson (2000)
2003 First human trial of gene therapy using modified
lentivirus as a vector
The vector used for this trial was based on human adenovirus type 5, deleted in
E1 and E4, and contained human OTC cDNA
Raper et al. (2003)
2006 Genetically engineered lymphocytes used for cancer
treatment
Adoptive transfer of these transduced cells in 15 patients resulted in durable
engraftment at levels exceeding 10% of peripheral blood lymphocytes for at least
2 months after the infusion
Morgan et al. (2006)
2010 CAR T-cell therapy study performed on B-cell
malignancies
Adoptive transfer of anti–CD19-CAR-expressing T cells is a promising new
approach for treating B-cell malignancies. The prolonged elimination of CD19
+
cells in this patient indicates in vivo antigen-specific activity of anti–CD19-CAR-
expressing T cells
Kochenderfer et al.
(2010)
2017 or
2018
The first gene therapy was approved in
United States
This year, the FDA approved two pioneering treatments, Kymriah and Yescarta,
that use a patient’s own immune cells to fight rare types of cancer
Ledford (2020)
2020 CRISPR treatment inserted directly into the body
for first time
Gene editing leaps to the next level with the injection of a CRISPR complex directly
into a patient’s eye to combat a form of hereditary blindness
Mahase (2021)
2021 NHS England agreed to a deal for gene therapy for
spinal muscular atrophy
NHS England agreed to a deal to ensure that Zolgensma, a one-off gene therapy
medicine, will be made available for patients with spinal muscular atrophy
Mahase (2021)
2022 Pediatric leukemia in remission after base-editing
cancer treatment in UK
GOSH in the UK released details of its first-in-human (T-cell ALL) clinical trial
using base-edited CAR T-cells
leukaemia (2022)
2022 The first allogeneic CAR T Phase 2 trial is initiated Potentially pivotal Phase 2 clinical trial of ALLO-501A in patients with relapsed or
refractory large B-cell lymphoma. ALLO-501A is TALEN-edited in a number of
ways to mitigate the risk of GVHD
Smirnov et al. (2021)
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pairing. This is generally accomplished by the incorporation of
either synthetic siRNAs or vector-derived shRNAs (Li et al., 2018).
This approach has potential advantages in the treatment of pediatric
cancers. For example, neuroblastoma cells harboring anaplastic
lymphoma kinase (ALK) mutations experienced growth
inhibition in experimental models following ALK silencing by
RNAi (Schulte and Eggert, 2021). Thus, the approach of silencing
oncogenic ALK could develop beneficial therapies for patients with
this particular abnormality (Ji et al., 2021). Furthermore, RNAi-
mediated targeting of beta-catenin in hepatoblastoma models
resulted in tumor growth suppression, suggesting another
potential target (Indersie et al., 2017). However, the challenge is
to deliver RNAi triggers specifically to the tumor tissue. MicroRNAs
(miRNAs), another regulatory approach, are short non-coding
RNAs that reduce protein production by binding to mRNAs
(Arraiano, 2021). A positive correlation was observed between
miRNAs expression and tumor grade and type, with the highest
expression noted in medulloblastomas, followed by ependymomas,
and the lowest in pilocytic astrocytomas. Upregulation was
predominantly observed in most members of the miR-17–92,
miR-106a-363, and miR-106b-25 clusters, with miR-18a and
miR-18b exhibiting the highest expression. Other miRNAs such
as miR-19a, miR-92a, miR-106a, miR-93, and miR-25 also
demonstrated elevated values. Additionally, miR-17-5p and miR-
20a displayed high expression levels in medulloblastomas and
ependymomas while approaching control levels in pilocytic
astrocytoma samples. Notably, miRNA expression was also
influenced by tumor grade and histology in pediatric
TABLE 3 Clinical trials of gene therapies for pediatric cancer.
Trial
identifier
Cancer type Gene
therapy
Gene
therapy
strategy
Combination
therapy
Phase Status Clinical trial Reference
NCT00634231 Pediatric brain
tumors, including
GBM, anaplastic
astrocytoma, and
recurrent
ependymomas
Adv-TK Viral vector
(adenovirus)
Valacyclovir +
radiation
I Active A Phase I study of
AdV-tk + prodrug
therapy in
combination with
radiation therapy for
pediatric brain
tumors
Kieran et al.
(2019)
NCT03330197 Pediatric brain
tumors or diffuse
intrinsic pontine
glioma (DIPG)
Ad-RTS-
Hil-12
Viral vector
(adenovirus)
Veledimex I/II Active A study of Ad-RTS-
Hil-12+veledimex in
pediatric subjects
with brain tumors or
DIPG
RTS (2023)
NCT02457845 Pediatric recurrent
or refractory
cerebellar brain
tumors
Oncolytic
HSV-1
Viral vector
(HSV-1)
Radiotherapy I Recruiting HSV G207 in
children with
recurrent or
refractory cerebellar
brain tumors
Friedman et al.
(2018)
NCT02435849 B-cell ALL Anti-CD19 Anti-CD19 CAR
T-cell
Tisagenlecleucel +
tocilizumab
II Completed A single infusion of
tisagenlecleucel
provided durable
remission with long-
term persistence in
pediatric and young
adult patients with
relapsed or
refractory B-cell
ALL, with transient
high-grade toxic
effects
Maude et al.
(2018)
NCT03284268 Retinoblastoma Oncolytic
adenovirus
Viral vector
(adenovirus)
VCN-01 I Recruiting Intravitreal
administration of
VCN-01 resulted in
anti-tumor activity
in retinoblastoma
vitreous granules
Pascual-Pasto
et al. (2019)
NCT03618381 Wilms tumor EGFR EGFR806 CAR-T
cell
EGFR806 CAR T-cell +
cetuximab/trastuzumab
I Recruiting Genetically modified
to express an EGFR-
specific receptor
(chimeric antigen
receptor or CAR)
that will target and
kill solid tumors that
express EGFR and
the selection suicide
marker EGFRt
Albert et al.
(2022)
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tumorigenesis, suggesting therapeutic potential for miRNA
(Gruszka et al., 2021). Measures such as adjusting abnormal
miRNA levels or using miRNAs to suppress fusion oncogenic
transcripts could be employed (Gambari et al., 2016). For example,
chemotherapy showed higher efficacy in neuroblastoma cells
where let-7 miRNA levels were restored (Jetal.,2015).
Nevertheless, the development of safe and effective miRNA-
based therapies has encountered many obstacles, such as
stability, off-target effects, and efficient delivery to target tissues
(Roy et al., 2022).
Targeted delivery of gene silencing therapies to malignant
cells is a challenging task (Safarzadeh Kozani et al., 2021a).
Systemic administration may induce off-target gene silencing
and consequent toxicity. Therefore, innovative delivery
systems are being explored to increase specificity and avoid
activation of immune responses (Zhao et al., 2020a). Studies
are considering the use of bioengineered viruses, liposomes,
and nanoparticles loaded with ligands for receptors
overexpressed on tumor cells (He et al., 2021). However,
other challenges remain, such as transient gene silencing and
variable silencing efficacy due to accessibility of the target site
(Safari et al., 2017).
In summary, despite the obstacles, gene silencing methods
could play a critical role in accurately targeting and silencing
genes that promote pediatric cancer growth (Verreault et al.,
2006). In summary, the advent of paradigm-shifting gene
editing technologies such as CRISPR and transcription
activator-like effector nucleases (TALENs) has invigorated
genetic research by providing customizable, targeted genome
editing capabilities. However, with the tremendous opportunity
comes the responsibility to guide the appropriate use of these
rapidly advancing tools that hold the power to permanently
recode life. Realizing their potential while mitigating the
risks will require ongoing ethical discussions and flexible
regulations based on scientific evidence. The coming decade
promises exciting advances in gene editing, but it also
demands caution.
3 Advantages and limitations of gene
therapy in the context of pediatric
cancer treatment
Breakthrough gene editing technologies such as CRISPR/
Cas9 and TALENs have advanced genetic engineering and
molecular biology research by facilitating precise genome editing
(Noel et al., 2021). The CRISPR/Cas9 system, derived from the
bacterial immune system, consists of the Cas9 enzyme that cleaves
DNA and a guide RNA that targets the precise DNA sequence for
modification. This mechanism allows for versatile genome
manipulation by deleting, adding, or modifying specific DNA
sequences (Aslam et al., 2021). Conversely, TALENs are
engineered enzymes designed to bind and cleave desired DNA
sites, providing an alternative precise genome editing approach
FIGURE 2
Challenges and limitations in pediatric cancer gene therapy.
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(Becker and Boch, 2021). These innovative techniques have
expanded opportunities in gene therapy, agriculture, and the
understanding of genetics and disease (Libutti, 2014).
CRISPR/Cas9 techniques have undergone significant
refinement, increasing the efficiency, specificity, and adaptability
of genome editing (Schreurs et al., 2021). A prominent development
in this area is prime editing, a sophisticated CRISPR technique that
introduces precise DNA edits without the need for double-strand
breaks or donor templates, instead inscribing new genetic
information directly into target sites (Hao et al., 2021). This
increases the range of potential edits while minimizing
unexpected mutations. Similarly, TALEN methods have
undergone significant improvements in design, assembly, and
delivery, resulting in improved precision of genetic modifications
(Sakuma et al., 2013). Emerging technology platforms now facilitate
automated, high-throughput assembly of customized TALENs
(Zhang et al., 2013). In addition, the combined use of TALENs
and CRISPR technologies promotes a synergistic effect that
optimizes precision and streamlines the editing process (Xu
et al., 2015).
In the field of medicine, CRISPR and TALENs have the potential
to precisely edit the human genome to treat genetic diseases by
permanently modifying disease-causing mutations (Xu et al., 2015;
Kesavan, 2023). An example of this has been reported in the
treatment of sickle cell disease by editing hematopoietic stem
cells (Anurogo et al., 2021). However, further improvements in
safety and efficacy are needed before these techniques meet
widespread clinical application (Anurogo et al., 2021). In
agriculture, gene editing has been used to create pest-resistant
crops and healthier livestock, a result touted to improve food
security (Karavolias et al., 2021). However, discussions about
regulations and appropriate applications continue. CRISPR and
TALENs have become critical research tools for genetic
screening, disease modeling, and elucidation of gene function in
cellular and animal models (Zhao et al., 2016).
The continued development of these impressive tools has
ethical, legal, and social implications that need to be addressed
(Zhao et al., 2016). Concerns have been raised about unintended
changes induced by CRISPR that deviate from the target gene, with
potentially far-reaching consequences. In addition, the notion of
human germline editing is controversial due to the potential risk of
permanent, heritable changes (de Wert, 2019). For this reason, an
ongoing dialogue among researchers, policymakers, and the public is
essential to establish a framework that balances benefits and risks.
Although gene editing has immense potential to combat disease,
improve food security, and deepen genetic understanding, it must be
approached cautiously because it involves permanent and extensive
changes to living systems. Regulatory policies must evolve with
scientific progress to guide responsible use (Rocha et al., 2020).
In summary, transformative gene editing technologies like
CRISPR and TALENs have supercharged genetics research
through customizable, targeted genome editing capabilities. But
along with the immense opportunities come responsibilities to
guide the appropriate use of these rapidly advancing tools that
can permanently alter the code of life. Harnessing their potential
while mitigating risks will require ongoing ethical debates and
evolving regulations rooted in scientific evidence. The next
decade of gene editing promises exciting progress but demands
prudence in equal measure.
3.1 Recent advances in gene therapy
strategies for pediatric cancer
The critical role of targeted gene delivery in gene therapy is
undeniable, particularly in realizing the potential to redefine the
treatment of genetic diseases (Pan et al., 2021). Among the tools at
our disposal for this purpose are adeno-associated viruses (AAVs),
which have shown impressive efficacy and specificity in delivering
therapeutic genes to target cells (Tustian and Bak, 2021). These are
not just viruses; they have been engineered to maximize delivery,
with new AAV variants engineered through capsid engineering to
improve targeting capabilities while minimizing the immune
responses triggered by their natural counterparts (Lugin et al.,
2020). For example, an optimized AAV was recently used in a
study to deliver CRISPR to the liver of a mouse, demonstrating high
specificity. AAVs have already found applications in clinical trials
for conditions such as inherited retinal diseases, spinal muscular
atrophy, and hemophilia (Moscoso and Steer, 2019).
There are also non-viral delivery systems in play, including lipid
nanoparticles (LNPs) and polymeric nanoparticles, which have
distinct advantages over viral vectors, such as a streamlined
production process, reduced immunogenicity, and the ability to
carry larger genetic cargo (Torres-Vanegas et al., 2021;Zohri et al.,
2021). The mRNA COVID-19 vaccines made possible by LNPs
illustrate their potential in gene therapy applications. Meanwhile,
polymeric nanoparticles have achieved preclinical success in
carrying CRISPR/Cas9 for gene editing as a possible therapy for
genetic diseases (Ahn et al., 2021;Andresen and Fenton, 2021).
However, we must continue to refine vectors and nanoparticles
to improve delivery efficiency and specificity while eliminating
toxicity. There is potential for synergistic effects when viral and
non-viral approaches are combined (Ren et al., 2021). For example,
LNPs could potentially attenuate the inflammation induced by viral
vectors. The importance of advancing gene delivery technology
cannot be overstated, as we aim to unleash the full power of
gene therapy in a range of applications, from genetic diseases to
vaccines (Piperno et al., 2021).
Gene therapy has already produced groundbreaking treatments
for certain inherited diseases; however, delivery has proven to be a
limiting factor in progress (Michalakis et al., 2021). The advent of a
new generation of customized viral vectors and non-viral systems
provides optimism that these hurdles can be overcome, paving the
way for a range of innovative gene therapies. It is critical that we
maintain rigorous standards of development and ethical use as these
powerful technologies are developed and applied (Ghosh
et al., 2020).
In summary, the prospects for targeted gene therapy are being
reshaped by the emergence of customized viral vectors and non-viral
nanoparticle systems. Further modifications and ethical oversight
are required to ensure the best therapeutic outcomes. The possibility
of synergistic effects with the combination of viral and non-viral
methods appears promising. Advances in gene therapy delivery
methods offer hope for precision gene therapies, provided that
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progress is guided by the responsibility to maintain safety and
ethical standards.
3.1.1 Viral vectors (retroviruses, lentiviruses,
adenoviruses, etc.)
Viral vectors have gained significant attention in gene therapy,
as they have been transformed into useful gene delivery mechanisms
due to their inherent ability to deliver genetic material into host cells.
The main variants used in this context are retroviruses, lentiviruses,
and adenoviruses (Giacca and Zacchigna, 2012).
Retroviruses, being RNA viruses, undergo a reverse
transcription process in which their RNA genome is converted to
DNA and further integrated into the host genome, facilitating
persistent and stable gene expression within the host cell. The
potential tumorigenesis induced by insertional mutagenesis is a
notable risk (Steckbeck et al., 2014;Sabatino et al., 2022). Indeed,
retroviruses exhibit efficient infection properties toward dividing
cells—an aspect that is critical for their application in ex vivo
treatments, as in the case of CAR T-cell therapy for leukemia
(Heyman et al., 2022).
Similar to retroviruses, lentiviruses can affect both dividing and
non-dividing cells, expanding their potential therapeutic
applications, including but not limited to neuroscience and
human immunodeficiency virus (HIV) treatment (Fassati, 2006).
One of their notable advantages is their broad cell tropism, which
allows them to transduce multiple cell type (Rainey and Coffin, 2006;
Poletti and Mavilio, 2018). However, the risk of insertional
mutagenesis associated with lentiviruses remains significant
(Woods et al., 2003). The class of adenoviruses, which are
double-stranded DNA viruses that do not integrate into the host
genome, greatly reduces the risk of mutagenesis (Charman et al.,
2019). Their efficacy in delivering transgenes to a variety of tissues in
vivo and ex vivo is complemented by their large transgene capacity
(Morrissey et al., 2012). They have shown impressive results in
cancer gene therapy, enabling localized delivery of tumor suppressor
genes (Wang et al., 2010). Their efficacy may be limited in certain
therapeutic settings due to anti-adenovirus immune responses
(Zhou et al., 2020).
Significant progress has been made in refining viral vector
design and production methods, which have greatly improved
safety and delivery efficiency (Li et al., 2021). An example is the
advent of self-inactivating vectors that reduce the oncogenic risks
associated with retroviruses and lentiviruses. Similarly, third-
generation adenoviral vectors are designed to minimize unwanted
immune activation (Troyanovsky et al., 2015;Shaw and
Suzuki, 2019).
In summary, despite their unique profiles, retroviral, lentiviral,
and adenoviral vectors have been instrumental in the advancement
of gene therapy. With continued improvements in viral vector
biology and engineering, their medical utility is expected to
expand. A better understanding of cell-specific targeting may lead
to vectors with superior therapeutic precision in the future.
3.1.2 Non-viral vectors (liposomes,
nanoparticles, etc.)
Due to the various challenges associated with viral vectors, such
as immunogenicity risk, limited payload capacity, and high
production costs (Luis, 2020), alternative non-viral vectors for
gene delivery have come to the forefront. These alternatives,
which include liposomes, nanoparticles, and others, have their
own unique advantages and specific issues that need to be
addressed (Musale and Giram, 2021).
Liposomes, spherical vesicles composed of lipid bilayers, have
been identified as safer alternatives capable of encapsulating and
delivering genes, proteins, or drugs with the added benefitof
minimizing immunogenic responses or infections (Liu et al.,
2022;van der Koog et al., 2022). One of the identified problems
with liposomes is that they often exhibit encapsulation efficiencies
below 20% (Costa et al., 2021), and there is a constant risk of rapid
degradation of the cargo before it reaches its intended target (Eloy
et al., 2014).
To address these limitations, cationic liposomes have been
developed to enhance encapsulation by facilitating the formation
of complexes with negatively charged nucleic acids (Ewert et al.,
2021). In addition, surface modifications, such as the attachment of
antibodies, peptides, or saccharides, can ensure that target specificity
is enabled (Lestini et al., 2002). For example, anti-EGFR nanobodies
have been attached to liposomes to facilitate targeted drug delivery
to colon cancer cells (Narbona et al., 2023). Further refinement of
the size, composition, and surface charge of these liposomes aims to
improve stability, efficiency, and cellular uptake (Ma et al., 2013).
Nanoparticles represent a diverse range of non-viral vectors
incorporating polymers, lipids, metals, or other elements (Botto
et al., 2018). For example, gold nanoparticles provide controlled,
sustained release of genes, making them invaluable in the treatment
of solid tumors (Zhao and Liu, 2014). Other nanoparticle vectors
include polymeric nanoparticles, quantum dots, and liposomal
nanoparticles (Ishihara et al., 2011). Polyplexes, a type of
nanoparticle vector, are widely used due to their ease of
production, safety, customization potential, and ability to
encapsulate various nucleic acids (Bai et al., 2014). Despite these
advantages, they still present challenges such as short circulation
time, low transfection efficiency, and cytotoxicity (Ita, 2020).
LNPs have shown potential for mRNA delivery, as
demonstrated by the use of mRNA COVID-19 vaccines
(Melamed et al., 2022). With high encapsulation efficiency,
biocompatibility, and stability, LNPs can be functionalized for
targeting (Alipour et al., 2017). To realize their full potential,
new surface modifications are being explored to increase stability,
reduce off-target effects, improve specificity, and decrease toxicity
(Kulkarni and Feng, 2011).
In conclusion, replacement non-viral vectors such as liposomes
and nanoparticles offer versatility that is stimulating research aimed
at overcoming current limitations. As safer alternatives to viral
vectors with the potential for significant optimization, they could
greatly improve gene therapy and drug delivery methods. Looking
ahead, the future seems bright for non-viral vectors as newer
designs, modifications, and combinations continue to emerge.
3.2 Immune-based gene therapies
3.2.1 CAR T-cell therapy
CAR T-cell therapy is a revolutionary approach to cancer
treatment that differs significantly from previous immunotherapy
techniques. This innovative therapy uses a patient’s own
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lymphocytes, commonly referred to as T-cells, to identify and
eradicate cancer cells with extreme precision (Xu et al., 2021).
The key steps in CAR T-cell therapy involve the isolation of a
patient’s T cells, followed by genetic modification using viral vectors
to create CARs, their subsequent expansion in vitro, and finally their
reintroduction into the patient’s body (Ke et al., 2021). These
engineered CARs can bind to target antigens on cancer cells with
an affinity in the nanomolar range, 100 to 1,000 times stronger than
natural antibodies (Harris and Kranz, 2016). This binding induces
cytotoxicity, resulting in the elimination of the cancer (Wang et al.,
2019). The structure of CARs consists of three main
components—an external moiety that binds to the tumor
antigen, a membrane spanning region, and an internal domain
that induces T-cell activation (Muller et al., 2021). The outer
segment typically uses a single-chain variable fragment (scFv)
derived from an antibody that confers specificity (Krokhotin
et al., 2019). The internal segment carries a CD3ζdomain
required for T-cell activation and costimulatory domains such as
CD28 or 4-1BB to enhance the activation signal (Boucher
et al., 2021).
CAR T-cell therapy has shown impressive results in blood
cancers, particularly B-cell acute lymphoblastic leukemia (B-ALL)
and diffuse large B-cell lymphoma (DLBCL), with treatments such
as Kymriah and Yescarta gaining FDA approval (Ma et al., 2019;
Safarzadeh Kozani et al., 2021b). However, the efficacy of therapy in
solid tumors is hampered by factors such as metastasis, tumor
diversity, and the immunosuppressive tumor environment (Zhao
et al., 2020b). Research is currently exploring potential solid tumor
targets such as GD2 in neuroblastoma and human epidermal growth
factor receptor 2 (HER2) in sarcoma (Straathof et al., 2020). To
enhance the efficacy of CAR T-cell therapy in solid tumors,
strategies such as regional administration and CARs that are
immune to suppressive signaling are being considered (Huang
et al., 2020).
Despite its great potential, CAR T-cell therapy has been
observed to induce cytokine release syndrome (CRS) in more
than 90% of patients and neurotoxicity due to overactivation in
about half of the cases (Napolitano et al., 2022). CRS is often treated
with drugs such as tocilizumab (Kauer et al., 2020). Ongoing efforts
are directed at integrating suicide genes into CARs to improve their
safety (Shi et al., 2020).
The future looks promising with the development of off-the-
shelf universal CAR T-cells, multi-antigen targeting CARs, and the
use of engineered Notch receptors to provide spatial control of CAR
T-cell activation (Qu et al., 2019). Advances in CAR T-cell therapy
could change the way cancer is treated. The ability to target solid
tumors and improve the safety of treatments is a particularly exciting
prospect in the evolution of this therapy.
3.2.2 Tumor-targeting antibodies
Tumor-targeting antibodies are an integral part of immune-
based cancer therapies. Their function depends on their ability to
distinguish antigens that are differentially expressed on cancer cells,
thus distinguishing these malignancies from healthy tissues. This
leads to selective targeting and a reduction in untargeted or “off-
target”effects (Hintz et al., 2021).
Over the past few decades, a number of these tumor-targeting
antibodies have been approved. These developments have greatly
improved the health outcomes of cancer patients (Sun et al., 2018).
Rituximab, for example, targets CD20 on B cells, which are used to
cure leukemia and lymphoma (Jain et al., 2021). Trastuzumab, on
the other hand, reacts with HER2, which is overexpressed in about
one-quarter to one-third of gastric and breast cancers and shows
increased survival rates (Upton et al., 2021). Another example,
cetuximab, blocks the epidermal growth factor receptor (EGFR),
which plays a role in metastasis and growth, and has shown efficacy
in colorectal and head and neck cancers (Dougherty et al., 2020;
Trivedi and Ferris, 2021).
The most common mechanisms of anti-tumor action include
blocking signaling pathways essential for cancer survival and
proliferation. These mechanisms also recruit natural killer cells to
enable antibody-dependent cellular cytotoxicity (ADCC). In
addition, these mechanisms activate the complement system to
enable complement-dependent cytotoxicity (CDC) (Murray et al.,
2014;Zhu et al., 2020). Another effect of this mechanism is that the
binding of the Fc region to cells of the immune system results in the
stimulation of the immune defense against the cancerous tumor
(Sasaki et al., 2020).
Nevertheless, resistance is observed in about half of all patients,
often allowing relapse after an initial response to treatment
(Licciardone and Aryal, 2014). This resistance can result from
several mechanisms, including loss of expression of the target
antigen, blockade of the antibody’s access to the cancer, and
activation of other survival pathways (Fernandes et al., 2021).
Another mechanism of resistance is through mutations in targets
that allow evasion of antibodies (da Silva, 2012). Notably, even
targeted therapies may have adverse effects due to non-specific
distribution (Swati, 2021).
Current research is focused on a few areas to address these issues
and further expand clinical utility. These areas include antibodies
that are bispecific or multispecific, which can bind to more than one
antigen as a method of not only improving specificity but also
overcoming resistance (Ahamadi-Fesharaki et al., 2019). Another
similar area of research is the study of drug–antibody conjugates,
which use antibodies to selectively deliver chemotherapeutic agents
or toxins (Pettinato, 2021). Another area of research is to increase
the activation of the immune system through Fc engineering (van
Tetering et al., 2020).
In sum, antibodies have had a significant impact on cancer care,
leading to improved outcomes in certain malignancies. Therefore, it
is highly likely that the future will see an expansion of antibodies as
strategic, selective tools in therapy that harnesses the immune
system to fight cancer.
3.2.3 Checkpoint inhibitors
Checkpoint inhibitors have significantly changed the landscape
of cancer immunotherapy through their ability to interfere with the
immune evasion mechanisms employed by tumors (Zhang et al.,
2021a). Tumor cells have developed sophisticated strategies to evade
the initial defenses of the immune system or to actively suppress
anti-cancer immunity mechanisms that have received considerable
attention in cancer research (Mahata et al., 2020).
Critical regulatory roles in modulating normal immune
responses and maintaining immune self-tolerance are played by
checkpoint proteins such as programmed cell death protein 1 (PD-
1), programmed death ligand 1 (PD-L1), and cytotoxic
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T-lymphocyte-associated antigen 4 (CTLA-4). PD-1, which is
typically expressed on T-cells, binds to PD-L1 on healthy cells,
and plays a regulatory role in preventing excessive T-cell activity
(Schutz et al., 2017;Chun et al., 2022). Paradoxically, the same
mechanism is used by tumor cells to evade T-cell attack by
presenting PD-L1 on their surface (Hinterleitner et al., 2021).
The introduction of PD-1 inhibitors interrupts this interaction,
reviving the suppressed T cells and enabling them to identify and
destroy tumor cells. This phenomenon has been demonstrated in the
treatment of several cancers, including but not limited to melanoma
and lung cancer (Curnock et al., 2021).
Also worthy of mention in the catalog of immune checkpoints is
CTLA-4, which acts to inhibit T-cell activation during later stages of
the immune response (Arra et al., 2021). Drugs such as ipilimumab
are designed to target CTLA-4 and enhance anti-tumor immunity
by removing this block to T-cell activation (Soldevilla et al., 2019).
Clinical trials have demonstrated the efficacy of CTLA-4 inhibitors
in the treatment of cancers, including melanoma (Hirshoren
et al., 2020).
However, checkpoint inhibitors are not without limitations.
More than half of treated patients experience immune-related
adverse events (irAEs), the severity of which can range from
mild to severe and in extreme cases can be life-threatening (Usui
et al., 2022). Diarrhea, dermatitis, and hepatitis are among the most
common irAEs (Spain et al., 2016). It is also noteworthy that some
tumors are “cold”or non-inflamed, characterized by sparse immune
cell infiltration into the tumor microenvironment. Patients with
such tumors are less likely to respond to checkpoint inhibitor
therapy (Gerard et al., 2021).
The scientific community is actively investigating strategies to
overcome these challenges. Combination therapies using checkpoint
inhibitors alongside other therapies such as chemotherapy,
radiation, or targeted therapy are of great interest (Andersson
and Ostheimer, 2019). Approaches aimed at making tumors
more susceptible (or “hotter”) to immunotherapy are also under
investigation, including the use of tumor antigen vaccines and
optimized drug delivery approaches (Liu et al., 2020). Research is
also underway to identify biomarkers that predict therapeutic
response and risk of side effects (Bartsch et al., 2007).
In summary, although checkpoint inhibitors are revolutionizing
cancer treatment through their ability to harness anti-tumor
immunity, which is typically limited by immune evasion
mechanisms employed by tumor cells, their efficacy is not
universal, and side effects remain a notable concern. Current
research efforts in combinatorial therapeutic strategies and
predictive biomarker identification are aimed at improving
clinical outcomes while minimizing toxic effects. Despite their
limitations, checkpoint inhibitors show significant potential to
improve cancer treatment. The challenge for the future is to
extend the durability and safety of therapeutic responses, which
will require continued research and innovation in the field.
4 Gene editing technologies and their
potential in pediatric cancer treatment
Gene modification technologies have advanced significantly and
have become critical in the study of cancer, particularly in pediatric
oncology (West and Gronvall, 2020). In this field, the CRISPR
system has proven to be particularly effective (Pomella and Rota,
2020). The CRISPR-Cas9 system allows scientists to precisely edit
genetic sequences, a concept borrowed from bacterial immune
defenses that precisely edit DNA (Neil et al., 2021). The
Cas9 enzyme has been likened to molecular scissors that use
RNA as a guide to specific genomic locations. This precision has
led to unprecedented opportunities in pediatric cancer treatment
(Smith et al., 2021).
The process of cancer development often involves the mutation or
inactivation of certain genes, causing cells to multiply uncontrollably.
Pediatric cancers are known for their aggressiveness and require prompt
treatment. The correct application of CRISPR-Cas9 allows for the
precise modification of defective genes, effectively halting or
eliminating the growth of cancer cells (Oberlick et al., 2019;Dharia
et al., 2021). Evidence from preclinical studies has underscored the
potential of CRISPR-Cas9 to treat several types of pediatric cancer. For
example, in neuroblastoma, CRISPR has been used to silence the
MYCN oncogene, which is typically dysregulated in high-risk cases,
resulting in a demonstrable anti-tumor effect (Yin et al., 2020). In
osteosarcoma models, the application of CRISPR led to a reduction in
tumor growth by targeting overactive TGF-βsignaling (Hu et al., 2018).
However, ensuring a safe, targeted delivery mechanism to cancer
cells while sparing healthy tissues remains a challenge and warrants
further research (Rizwanullah et al., 2021). Approaches such as viral
vectors are being explored to improve cell type specificity (Levy et al.,
2020). In addition, the ethical issues associated with gene editing
cannot be understated. The indelible nature of genetic modifications
requires careful consideration of unintended off-target effects and
long-term consequences, such as permanent changes in the germ
line (Feeney, 2019).
In conclusion, while there is reason for optimism, in-depth
clinical trials are essential to confirm the efficacy and safe application
of CRISPR gene editing for pediatric cancers. Precision and accuracy
of editing, coupled with minimal risks, are critical considerations
before this technology is applied in clinical settings. Despite the clear
challenges, the potential of this technology to revolutionize cancer
treatment is profound.
5 Combination therapies involving
gene therapy for enhanced efficacy
Gene therapy aims to treat diseases at their genetic root (Cicalese
and Aiuti, 2020). However, refining and perfecting gene therapy
remains a challenge. Research is underway to determine where gene
therapy can be combined with other treatments to increase efficacy
(Nastiuk and Krolewski, 2016). One promising approach has been to
combine gene therapy with pharmacological or biological agents,
especially in the case of complex genetic diseases (Rex, 2015).
Improved outcomes have been reported in lysosomal storage
disorders where gene therapy has been combined with enzyme
replacement therapy (Li, 2018). Oncology researchers are
investigating the use of gene therapy in combination with
chemotherapy or immunotherapy to improve response (Chada
et al., 2022). The logic of this approach is to augment the
benefits of gene therapy with other treatment modalities (Lin
et al., 2021). The combination of therapies may result in
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synergistic effects that exceed the effects of individual treatments,
especially in diseases with both environmental and genetic
contributions (Gaikani et al., 2021). Advanced gene editing
techniques, such as CRISPR, and gene silencing methods,
including RNA interference, are enabling innovations in
combination therapies by allowing direct modification of gene
sequence or expression (Zhang et al., 2021b). A comprehensive
approach that integrates these methods with gene therapy may
improve outcomes compared to any single therapy (Mac
Gabhann et al., 2010). However, comprehensive studies are
needed to ensure safety and long-term effects. Potential risks
include off-target effects, unintended immune responses, and the
need for lifelong monitoring (Kelley et al., 2002). In addition,
research is needed to determine optimal dosing, timing, and
patient selection to maximize benefits and minimize side effects
(Ngoune et al., 2018).
In summary, strategies involving gene therapy represent a
promising avenue for the treatment of complex diseases if
existing challenges can be overcome. Despite the tremendous
potential, ensuring safety and efficacy remains of paramount
importance as these therapies continue to be refined and
optimized. The future holds great promise for combination gene
therapies, but careful and comprehensive research is essential to
successfully translate this promise from theory to clinical practice.
6 Clinical applications and success
stories in pediatric cancer
6.1 Overview of gene therapy clinical trials in
pediatric cancer
Gene therapy is recognized as an important experimental
approach to the treatment of pediatric cancers, the leading cause
of disease-related death in children (Bornhorst and Hwang, 2016).
Table 3 shows several clinical trials of gene therapies for pediatric
cancer. Clinical trials are essential for evaluating efficacy and safety
prior to clinical use (Jacobson et al., 2021). These trials typically
progress through three phases, each with increasing numbers of
participants, to methodically study efficacy and adverse effects in
larger populations (Gore, 2003). For example, phase I trials confirm
safety in a small cohort, phase II trials expand the cohort to evaluate
efficacy, and phase III trials compare a new treatment with standard
therapies using large cohorts (Millen and Yap, 2021).
Extensive preclinical studies providing proof of concept and
confirming an appropriate therapeutic index provide a layer of safety
before human trials begin. A prime example is CRISPR-Cas9, which
allows precise editing of disease-causing mutations using a guide
RNA to direct the Cas9 enzyme to desired DNA sequences (Suresh,
2021). Optimization of gene delivery methods is also part of
preclinical work using animal models and cell culture
experiments (Bez et al., 2019).
Early phase studies have already demonstrated the potential
success of gene therapy in non-cancer diseases, including sickle cell
disease, inherited retinal diseases, HIV, and transthyretin amyloidosis
(Grimley et al., 2020). Clinical improvements in disease markers and
symptom manifestations in patients suggest considerable potential for
pediatric cancers as well (Delforge et al., 2022).
Despite these promising advances, risks such as off-target effects,
where gene modifications inadvertently alter other genomic sites,
warrant attention. An unintended consequence could be the onset of
cancer if genes that suppress tumors are silenced (Peltomaki, 2012).
Another potential risk is immunogenicity, or the induction of an
immune response against the introduced genetic material (Koyama
et al., 2009). The long-term effects of permanent changes in the
genome are still unclear and undefined (Long et al., 2011). Trial
participants must be fully informed that there is no guarantee of
benefit and that unforeseen risks may occur (Dube et al., 2017).
Intensive research efforts are essential to develop the promising
initial results before gene therapy can be widely applied to childhood
cancers (Khan and Helman, 2016). Key priorities include optimizing
patient selection, delivery methods, dosing, and management of side
effects. Further advances in technology and thorough scientific
investigation are essential to ultimately realize the rich potential
of gene therapy for the benefit of children with cancer.
6.2 Successful cases of gene therapy in
pediatric cancer treatment
Gene therapy, an innovative form of treatment that works by
altering the genes within an individual’s cells, has shown
considerable therapeutic potential, particularly in pediatric
malignancies (Handgretinger and Schlegel, 2018). The process
involves addressing and correcting abnormalities caused by
mutations, thereby restoring the normal function of proteins that
may be dysfunctional or missing (Handgretinger and Schlegel,
2018). Several implementations of this approach have been
successful in pediatric oncology, as described below.
A strategy known as gene addition is proving effective against
diseases that arise from a single gene. A functional variant of an
underperforming gene is introduced into the system using specially
programmed viral or non-viral vectors. As a result, the introduced
gene compensates for the deficiency by producing the previously
missing proteins (Zeng et al., 2021). Examples of remarkable effects
of this method can be seen in the treatment of neuroblastoma, where
the administration of a gene-encoded antibody via an adenoviral
vector significantly reduced tumor size in the majority of patients in
clinical trials (Chen et al., 2022). The gene-addition strategy has also
been successful in ameliorating the effects of X-linked severe
combined immunodeficiency, a disorder that renders individuals
susceptible to infectious diseases (Blanco et al., 2020).
An alternative treatment method, post-transcriptional gene
silencing, works by neutralizing specific messenger RNAs to
prevent expression of the affected gene. This approach has been
used to knock out the MYCN oncogene in high-risk neuroblastoma,
significantly slowing cancer cell growth (Mendez et al., 2015).
Targeting and silencing ALK oncogenic mutations with this
method also significantly reduced tumor progression in
neuroblastoma models (Durand et al., 2019).
In addition, gene editing, which involves the modification,
deletion, or addition of DNA, is another tool in the application
of gene therapy to pediatric malignancies (Zhang et al., 2021b). Of
note in this category is CAR T-cell therapy, which showed efficacy
when tested in pediatric leukemia (Greinix, 2019). Promising results
have also been observed in preliminary studies when PD-1 was
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edited to induce T cells to attack osteosarcoma tumors (Fan
et al., 2021).
The mechanics of each of these gene therapy platforms rely
heavily on the delivery of genetic material via a compendium of
engineered viral or non-viral vectors—a critical component of the
entire operation (Bulcha et al., 2021). The examples presented
highlight the monumental progress that has been made to date
in the treatment of pediatric cancers with gene therapy. However,
further exploration of the long-term implications is warranted, and a
comprehensive risk-benefit analysis should be conducted in
consultation with health care professionals. As research continues
to improve the efficacy of gene therapy, we cannot overlook the
significant potential this approach brings to the field of pediatric
cancer treatment.
6.3 Challenges and limitations encountered
in clinical applications
Clinical applications of gene therapy for pediatric cancers have
made progress but still face significant challenges that limit
widespread adoption and success (Xia et al., 2020).
One major challenge stems from the complexity of pediatric
tumors. Unlike adult cancers that accumulate mutations, pediatric
malignancies often arise from developmental defects that
compromise the efficacy of gene therapy (Jessa et al., 2019;
Blattner-Johnson et al., 2022). For example, pediatric brain
tumors such as medulloblastoma have different underlying
biology and growth patterns than adult tumors, making them
less amenable to certain gene therapy approaches. In addition,
determining the optimal dosage, timing, and delivery method
poses significant hurdles (Li and Langhans, 2021). Careful fine-
tuning is essential to maximize tumor destruction while minimizing
toxicity and side effects, requiring intensive monitoring (Pasquier
et al., 2019). In a trial for recurrent high-grade glioma, some patients
experienced brain inflammation and neurologic toxicity, which were
attributed to difficulties with dose calibration (Chiocca et al., 2019).
Of great concern are potential long-term unintended
consequences. The introduction of genetic modifications risks
“off-target”effects on genes other than the intended target,
potentially triggering problems such as secondary cancers
(Nelson et al., 2019). Tragically, X-linked severe combined
immune deficiency (X-SCID) gene therapy trials inadvertently
caused leukemia in some patients due to activation of the
LMO2 oncogene (Ruggero et al., 2016).
In addition, patients’immune systems may attack the
introduced genes, reducing efficacy and jeopardizing health
(Ledford and Callaway, 2018). In an X-SCID trial, some patients
developed an immune response that attacked their own blood cells
(Ehl et al., 2005). Other barriers include complex regulations,
exorbitant manufacturing/distribution costs, and specialized
administration (Ehl et al., 2005). For example, it took more than
20 years from the first cancer gene therapy trials to FDA approval of
CAR T-cell therapy in 2017 (Libutti, 2019).
In summary, pediatric cancer gene therapy still faces challenges,
including tumor biology, treatment optimization, unintended
effects, immune responses, regulations, and implementation
(Figure 2). Continued innovation in vectors, delivery, and
precision oncology may help overcome these barriers and realize
the promise of gene therapy for children with cancer. While hurdles
remain, the possibilities make it a worthwhile pursuit.
7 Potential risks and adverse effects
associated with gene therapy in
pediatric patients
Although gene therapy holds great promise for the treatment of
childhood cancers, it is associated with various risks and adverse
effects that must be carefully evaluated. A key hurdle is the precise
manipulation of genes to target disease without causing unintended
harmful side effects (Wedekind et al., 2018).
Significant risks are associated with the vectors used to deliver
therapeutically important genes into cells. Despite their regular use,
even modified viral vectors are known to induce unwanted immune
responses, leading to inflammatory or allergic reactions. A clinical
trial of adenoviral vectors for ornithine transcarbamylase deficiency
resulted in the unfortunate death of a pediatric patient due to a
severe immunologic reaction to the viral carrier (Brown et al., 2017).
There is also the potential for off-target effects. While the goal is to
replace defective genes, unintended alteration of other genes may
occur. Such unintended changes can have potentially adverse health
consequences, including the development of secondary cancers. For
example, in a trial for X-linked severe combined immunodeficiency,
gene therapy inadvertently activated the LMO2 proto-oncogene,
leading to leukemia in some patients (Qasim and Gkazi, 2019).
In addition, the irreversible nature of gene modification can
result in adverse effects that may not manifest until later in a
patient’s life. Particularly in pediatric cases, predicting long-term
outcomes is complex (Baum et al., 2003). For example, in animal
models, gene therapy used to treat mucopolysaccharidosis has been
associated with the later onset of neurological and skeletal
abnormalities (Zapolnik and Pyrkosz, 2021). There is also a risk
of insertional mutagenesis, a process in which newly inserted genetic
material disrupts other genes. Integration of viral vectors could
induce mutations by activating oncogenes, potentially causing
cancer. In clinical trials of X-linked chronic granulomatous
disease, vector insertion appeared to induce malignant
transformation in some patients (Knight et al., 2013;Ha et al., 2021).
In addition, risks have been identified related to germline effects,
where genetic alterations in pediatric patients could be inherited by
future generations. This issue raises significant ethical concerns,
particularly in the case of non-life-threatening diseases (Rubeis and
Steger, 2018). The implementation of strict safeguards around vector
delivery to target tissues is critical to prevent unintended germline
transmission. From an ethical perspective, the relatively novel
nature of gene therapy, coupled with permanent genetic
alterations, requires careful consideration in obtaining informed
consent in pediatric patients to protect vulnerable pediatric patients
and their families from potential exploitation (Rubeis and
Steger, 2018).
In summary, risks such as immune reactions, off-target effects,
long-term effects, insertional mutagenesis, germline transmission,
and ethical dilemmas must be addressed to realize the full potential
of gene therapy in pediatric cancer. Ongoing research is aimed at
optimizing vectors, improving precision delivery, and monitoring
Frontiers in Molecular Biosciences frontiersin.org12
Moaveni et al. 10.3389/fmolb.2024.1382190
long-term effects to reduce risks and safely extend the benefits of
gene therapy to more pediatric patients. Although there are risks
involved, the judicious use of gene therapy offers a glimmer of hope
for many children who have previously faced a shortened life
expectancy.
8 Conclusion
Pediatric oncology is poised for revolutionary advances due to
the significant potential of gene therapy. Ongoing research efforts to
unravel the genetics of pediatric cancer have made it increasingly
important to foster interdisciplinary collaboration to improve gene
therapy applications. Concurrent initiatives encourage collaboration
among clinicians, researchers, and advocates to accelerate the
clinical translation process.
Gene therapy offers extraordinary potential to transform
pediatric cancer treatment by facilitating targeted, personalized
therapeutic strategies that minimize toxicity to healthy cells. Its
efficacy has been validated by early successes, demonstrating the
possibility of a durable and precise treatment era. However, realizing
the full potential of gene therapy will require overcoming hurdles
related to delivery, safety, policy, and social inequalities and will
require a concerted focus on strategic innovation and reform.
Equally critical is the management of expectations, as the clinical
translation of many emerging gene therapies remains a
distant reality.
Looking ahead, the field appears poised for accelerated progress,
driven by scientific innovation and cross-sector collaboration. The
role of gene therapy is expected to expand and significantly
contribute to improving pediatric cancer survival rates while
enhancing quality of life. Maximizing the benefits will require
continued research, advocacy, and policy advances to catalyze the
transformative journey from the laboratory to the clinic.
Underpinned by the patient-centered core principle, the future
appears hopeful and filled with opportunities to translate the
tremendous promise of gene therapy into accessible treatments
for pediatric patients worldwide.
Author contributions
AM: writing–original draft. MA: data curation, visualization,
and writing–original draft. BS: writing–original draft. AF:
conceptualization, project administration, visualization, and
writing–review and editing. JB: visualization and writing–original
draft. AN: writing–review and editing.
Funding
The author(s) declare that no financial support was received for
the research, authorship, and/or publication of this article.
Conflict of interest
The authors declare that the research was conducted in the
absence of any commercial or financial relationships that could be
construed as a potential conflict of interest.
Publisher’s note
All claims expressed in this article are solely those of the authors
and do not necessarily represent those of their affiliated
organizations, or those of the publisher, the editors, and the
reviewers. Any product that may be evaluated in this article, or
claim that may be made by its manufacturer, is not guaranteed or
endorsed by the publisher.
References
Agrawal, S., and Bansal, N. (2019). Advances and challenges in pediatric cancers.
Cancer Rep. 2 (3). doi:10.1002/cnr2.1202
Ahamadi-Fesharaki, R., Fateh, A., Vaziri, F., Solgi, G., Siadat, S. D., Mahboudi, F., et al.
(2019). Single-chain variable fragment-based bispecific antibodies: hitting two targets with
one sophisticated arrow. Mol. Ther. Oncolytics 14, 38–56. doi:10.1016/j.omto.2019.02.004
Ahn, M., Song, J., and Hong, B. H. (2021). Facile synthesis of N-doped graphene
quantum dots as novel transfection agents for mRNA and pDNA. Nanomater. (Basel)
11 (11), 2816. doi:10.3390/nano11112816
Albert, C. M., Pinto, N. R., Taylor, M., Wilson, A., Rawlings-Rhea, S., Mgebroff, S.,
et al. (2022). STRIvE-01: phase I study of EGFR806 CAR T-cell immunotherapy for
recurrent/refractory solid tumors in children and young adults. J. Clin. Oncol. 40 (16_
Suppl. l), 2541. doi:10.1200/jco.2022.40.16_suppl.2541
Aledo-Serrano, A., Gil-Nagel, A., Isla, J., Mingorance, A., Mendez-Hermida, F., and
Hernandez-Alcoceba, R. (2021). Gene therapies and COVID-19 vaccines: a necessary
discussion in relation with viral vector-based approaches. Orphanet J. Rare Dis. 16 (1),
316. doi:10.1186/s13023-021-01958-3
Alipour, E., Halverson, D., McWhirter, S., and Walker, G. C. (2017). Phospholipid
bilayers: stability and encapsulation of nanoparticles. Annu. Rev. Phys. Chem. 68,
261–283. doi:10.1146/annurev-physchem-040215-112634
Andersson, P., and Ostheimer, C. (2019). Editorial: combinatorial approaches to
enhance anti-tumor immunity: focus on immune checkpoint blockade therapy. Front.
Immunol. 10, 2083. doi:10.3389/fimmu.2019.02083
Andresen, J. L., and Fenton, O. S. (2021). Nucleic acid delivery and nanoparticle
design for COVID vaccines. MRS Bull. 46 (9), 832–839. doi:10.1557/s43577-021-
00169-2
Anurogo, D., Yuli Prasetyo Budi, N., Thi Ngo, M. H., Huang, Y. H., and Pawitan, J. A.
(2021). Cell and gene therapy for anemia: hematopoietic stem cells and gene editing. Int.
J. Mol. Sci. 22 (12), 6275. doi:10.3390/ijms22126275
Arra, A., Pech, M., Fu, H., Lingel, H., Braun, F., Beyer, C., et al. (2021). Immune-
checkpoint blockade of CTLA-4 (CD152) in antigen-specific human T-cell responses
differs profoundly between neonates, children, and adults. Oncoimmunology 10 (1),
1938475. doi:10.1080/2162402X.2021.1938475
Arraiano, C. M. (2021). Regulatory noncoding RNAs: functions and applications in
health and disease. FEBS J. 288 (22), 6308–6309. doi:10.1111/febs.16027
Aslam, M. A., Hammad, M., Ahmad, A., Altenbuchner, J., and Ali, H. (2021). in
Delivery methods, resources and design tools in CRISPR/Cas. Editors A. Ahmad,
S. H. Khan, and Z. Khan (Germany: Springer).
Atkins, A., Chung, C. H., Allen, A. G., Dampier, W., Gurrola, T. E., Sariyer, I. K., et al.
(2021). Off-Target analysis in gene editing and applications for clinical translation of
CRISPR/Cas9 in HIV-1 therapy. Front. Genome 3, 673022. doi:10.3389/fgeed.2021.673022
Aydin, C., Cetin, Z., Manguoglu, A. E., Tayfun, F., Clark, O. A., Kupesiz, A., et al.
(2016). Evaluation of ETV6/RUNX1 fusion and additional abnormalities involving
ETV6 and/or RUNX1 genes using FISH technique in patients with childhood acute
lymphoblastic leukemia. Indian J. Hematol. Blood Transfus. 32 (2), 154–161. doi:10.
1007/s12288-015-0557-7
Bai, M., Bai, X., and Wang, L. (2014). Real-time fluorescence tracking of gene delivery via
multifunctional nanocomposites. Anal. Chem. 86 (22), 11196–11202. doi:10.1021/ac5026489
Bartsch, H., Dally, H., Popanda, O., Risch, A., and Schmezer, P. (2007). Genetic risk
profiles for cancer susceptibility and therapy response. Recent Results Cancer Res. 174,
19–36. doi:10.1007/978-3-540-37696-5_2
Frontiers in Molecular Biosciences frontiersin.org13
Moaveni et al. 10.3389/fmolb.2024.1382190
Baum, C., Dullmann, J., Li, Z., Fehse, B., Meyer, J., Williams, D. A., et al. (2003). Side
effects of retroviral gene transfer into hematopoietic stem cells. Blood 101 (6),
2099–2114. doi:10.1182/blood-2002-07-2314
Becker, S., and Boch, J. (2021). TALE and TALEN genome editing technologies. Gene
Genome Ed. 2, 100007. doi:10.1016/j.ggedit.2021.100007
Bez, M., Foiret, J., Shapiro, G., Pelled, G., Ferrara, K. W., and Gazit, D. (2019).
Nonviral ultrasound-mediated gene delivery in small and large animal models. Nat.
Protoc. 14 (4), 1015–1026. doi:10.1038/s41596-019-0125-y
Bhattacharjee, G., Gohil, N., Khambhati, K., Mani, I., Maurya, R., Karapurkar, J. K.,
et al. (2022). Current approaches in CRISPR-Cas9 mediated gene editing for biomedical
and therapeutic applications. J. Control Release 343, 703–723. doi:10.1016/j.jconrel.
2022.02.005
Blanco, E., Izotova, N., Booth, C., and Thrasher, A. J. (2020). Immune reconstitution
after gene therapy approaches in patients with X-linked severe combined
immunodeficiency disease. Front. Immunol. 11, 608653. doi:10.3389/fimmu.2020.608653
Blattner-Johnson, M., Jones, D. T. W., and Pfaff, E. (2022). Precision medicine in
pediatric solid cancers. Semin. Cancer Biol. 84, 214–227. doi:10.1016/j.semcancer.2021.
06.008
Bordignon, C., Notarangelo, L. D., Nobili, N., Ferrari, G., Casorati, G., Panina, P., et al.
(1995). Gene therapy in peripheral blood lymphocytes and bone marrow for ADA-
immunodeficient patients. Science 270 (5235), 470–475. doi:10.1126/science.270.
5235.470
Bornhorst, M., and Hwang, E. I. (2016). Experimental therapeutic trial design for
pediatric brain tumors. J. Child. Neurol. 31 (12), 1421–1432. doi:10.1177/
0883073815604221
Botto, C., Augello, G., Amore, E., Emma, M. R., Azzolina, A., Cavallaro, G., et al.
(2018). Cationic solid lipid nanoparticles as non viral vectors for the inhibition of
hepatocellular carcinoma growth by RNA interference. J. Biomed. Nanotechnol. 14 (5),
1009–1016. doi:10.1166/jbn.2018.2557
Boucher, J. C., Li, G., Kotani, H., Cabral, M. L., Morrissey, D., Lee, S. B., et al. (2021).
CD28 costimulatory domain-targeted mutations enhance chimeric antigen receptor
T-cell function. Cancer Immunol. Res. 9 (1), 62–74. doi:10.1158/2326-6066.CIR-20-
0253
Brown, N., Song, L., Kollu, N. R., and Hirsch, M. L. (2017). Adeno-Associated virus
vectors and stem cells: friends or foes? Hum. Gene Ther. 28 (6), 450–463. doi:10.1089/
hum.2017.038
Bulcha, J. T., Wang, Y., Ma, H., Tai, P. W. L., and Gao, G. (2021). Viral vector
platforms within the gene therapy landscape. Signal Transduct. Target Ther. 6 (1), 53.
doi:10.1038/s41392-021-00487-6
Campbell, K., Ma, C., and DuBois, S. G. (2020). New approaches to therapeutic drug
development for childhood cancers. Curr. Opin. Pediatr. 32 (1), 35–40. doi:10.1097/
MOP.0000000000000850
Capasso, M., Montella, A., Tirelli, M., Maiorino, T., Cantalupo, S., and Iolascon, A.
(2020). Genetic predisposition to solid pediatric cancers. Front. Oncol. 10, 590033.
doi:10.3389/fonc.2020.590033
Chada, S., Wiederhold, D., Menander, K. B., Sellman, B., Talbott, M., Nemunaitis, J. J.,
et al. (2022). Tumor suppressor immune gene therapy to reverse immunotherapy
resistance. Cancer Gene Ther. 29 (6), 825–834. doi:10.1038/s41417-021-00369-7
Charman, M., Herrmann, C., and Weitzman, M. D. (2019). Viral and cellular
interactions during adenovirus DNA replication. FEBS Lett. 593 (24), 3531–3550.
doi:10.1002/1873-3468.13695
Chen, C., Yang, Z., and Tang, X. (2018). Chemical modifications of nucleic acid dru gs
and their delivery systems for gene-based therapy. Med. Res. Rev. 38 (3), 829–869.
doi:10.1002/med.21479
Chen, X. T., Dai, S. Y., Zhan, Y., Yang, R., Chen, D. Q., Li, Y., et al. (2022). Progress of
oncolytic virotherapy for neuroblastoma. Front. Pediatr. 10, 1055729. doi:10.3389/fped.
2022.1055729
Childhood Cancer (2023). Childhood cancer. Available at: https://www.who.int/
news-room/fact-sheets/detail/cancer-in-children.
Chiocca, E. A., Yu, J. S., Lukas, R. V., Solomon, I. H., Ligon, K. L., Nakashima, H., et al.
(2019). Regulatable interleukin-12 gene therapy in patients with recurrent high-grade
glioma: results of a phase 1 trial. Sci. Transl. Med. 11 (505), eaaw5680. doi:10.1126/
scitranslmed.aaw5680
Chun, K. S., Kim, D. H., Raut, P. K., and Surh, Y. J. (2022). Anticancer natural
products targeting immune checkpoint protein network. Semin. Cancer Biol. 86 (Pt 3),
1008–1032. doi:10.1016/j.semcancer.2021.11.006
Cicalese, M. P., and Aiuti, A. (2020). New perspectives in gene therapy for inherited
disorders. Pediatr. Allergy Immunol. 31 (Suppl. 24), 5–7. doi:10.1111/pai.13149
Costa, C., Liu, Z., Simoes, S. I., Correia, A., Rahikkala, A., Seitsonen, J., et al. (2021).
One-step microfluidics production of enzyme-loaded liposomes for the treatment of
inflammatory diseases. Colloids Surf. B Biointerfaces 199, 111556. doi:10.1016/j.colsurfb.
2020.111556
Curnock, A. P., Bossi, G., Kumaran, J., Bawden, L. J., Figueiredo, R., Tawar, R., et al.
(2021). Cell-targeted PD-1 agonists that mimic PD-L1 are potent T cell inhibitors. JCI
Insight 6 (20), e152468. doi:10.1172/jci.insight.152468
Danaeifar, M. (2022). Recent advances in gene therapy: genetic bullets to the root of
the problem. Clin. Exp. Med. 23, 1107–1121. doi:10.1007/s10238-022-00925-x
Das, S. K., Menezes, M. E., Bhatia, S., Wang, X. Y., Emdad, L., Sarkar, D., et al. (2015).
Gene therapies for cancer: strategies, challenges and successes. J. Cell. Physiol. 230 (2),
259–271. doi:10.1002/jcp.24791
da Silva, J. (2012). Antibody selection and amino acid reversions. Evolution 66 (10),
3079–3087. doi:10.1111/j.1558-5646.2012.01686.x
de Lartigue, J. (2018). Game changers in pediatric cancer. J. Community Support.
Oncol. 16 (5), e210–e216. doi:10.12788/jcso.0430
Delforge, M., Shah, N., Miguel, J. S. F., Braverman, J., Dhanda, D. S., Shi, L., et al.
(2022). Health-related quality of life with idecabtagene vicleucel in relapsed and
refractory multiple myeloma. Blood Adv. 6 (4), 1309–1318. doi:10.1182/
bloodadvances.2021005913
Deverman, B. E., Ravina, B. M., Bankiewicz, K. S., Paul, S. M., and Sah, D. W. Y.
(2018). Gene therapy for neurological disorders: progress and prospects. Nat. Rev. Drug
Discov. 17 (9), 767–859. doi:10.1038/nrd.2018.158
de Wert, G. (2019). Human germline gene editing. Recommendations of the
European society of human genetics and the European society of human
reproduction and embryology. Reprod. Biomed. Online 38, e61–e62. doi:10.1016/j.
rbmo.2019.03.097
Dharia, N. V., Kugener, G., Guenther, L. M., Malone, C. F., Durbin, A. D., Hong, A. L.,
et al. (2021). A first-generation pediatric cancer dependency map. Nat. Genet. 53 (4),
529–538. doi:10.1038/s41588-021-00819-w
Dobson, R. (2000). Gene therapy saves immune deficient babies in France. BMJ 320
(7244), 1225. doi:10.1136/bmj.320.7244.1225
Dougherty, M. I., Lehman, C. E., Spencer, A., Mendez, R. E., David, A. P., Taniguchi,
L. E., et al. (2020). PRAS40 phosphorylation correlates with insulin-like growth fac tor-1
receptor-induced resistance to epidermal growth factor receptor inhibition in head and
neck cancer cells. Mol. Cancer Res. 18 (9), 1392–1401. doi:10.1158/1541-7786.MCR-19-
0592
Dube, K., Taylor, J., Sylla, L., Evans, D., Dee, L., Burton, A., et al. (2017). Well, it’sthe
risk of the unknown. Right?’: a qualitative study of perceived risks and benefits of HIV
cure research in the United States. PLoS One 12 (1), e0170112. doi:10.1371/journal.
pone.0170112
Durand, S., Pierre-Eugene, C., Mirabeau, O., Louis-Brennetot, C., Combaret, V.,
Colmet-Daage, L., et al. (2019). ALK mutation dynamics and clonal evolution in a
neuroblastoma model exhibiting two ALK mutations. Oncotarget 10 (48), 4937–4950.
doi:10.18632/oncotarget.27119
Ehl, S., Schwarz, K., Enders, A., Duffner, U., Pannicke, U., Kuhr, J., et al. (2005). A
variant of SCID with specific immune responses and predominance of gamma delta
T cells. J. Clin. Investig. 115 (11), 3140–3148. doi:10.1172/JCI25221
Eloy, J. O., Claro de Souza, M., Petrilli, R., Barcellos, J. P., Lee, R. J., and Marchetti,
J. M. (2014). Liposomes as carriers of hydrophilic small molecule drugs: strategies to
enhance encapsulation and delivery. Colloids Surf. B Biointerfaces 123, 345–363. doi:10.
1016/j.colsurfb.2014.09.029
Ewert, K. K., Scodeller, P., Simon-Gracia, L., Steffes, V. M., Wonder, E. A., Teesalu, T.,
et al. (2021). Cationic liposomes as vectors for nucleic acid and hydrophobic drug
Therapeutics. Pharmaceutics 13 (9), 1365. doi:10.3390/pharmaceutics13091365
Fan, M. K., Qi, L. L., Zhang, Q., and Wang, L. (2021). The updated status and future
direction of immunotherapy targeting B7-H1/PD-1 in osteosarcoma. Cancer Manag.
Res. 13, 757–764. doi:10.2147/CMAR.S285560
Fassati, A. (2006). HIV infection of non-dividing cells: a divisive problem.
Retrovirology 3, 74. doi:10.1186/1742-4690-3-74
Feeney, O. (2019). Editing the gene editing debate: reassessing the normative
discussions on emerging genetic technologies. NanoEthics 13 (3), 233–243. doi:10.
1007/s11569-019-00352-5
Fernandes, M., Jamme, P., Cortot, A. B., Kherrouche, Z., and Tulasne, D. (2021).
When the MET receptor kicks in to resist targeted therapies. Oncogene 40 (24),
4061–4078. doi:10.1038/s41388-021-01835-0
Friedman,G.,Bag,A.,Madan-Swain,A.,Li,R.,Kachurak,K.,Osorio,D.,etal.
(2018). Immu-08. Phase I trial (Nct02457845) safety, tolerability and preliminary
efficacy of immunovirotherapy with hsv G207 in children with progressive malignant
supratentorial brain tumors. Neuro-Oncology 20, i100. doi:10.1093/neuonc/
noy059.324
Gaikani, H., Smith, A. M., Lee, A. Y., Giaever, G., and Nislow, C. 2021.
Gambari, R., Brognara, E., Spandidos, D. A., and Fabbri, E. (2016). Targeting
oncomiRNAs and mimicking tumor suppressor miRNAs: Νew trends in the
development of miRNA therapeutic strategies in oncology (Review). Int. J. Oncol.
49 (1), 5–32. doi:10.3892/ijo.2016.3503
Gerard, C. L., Delyon, J., Wicky, A., Homicsko, K., Cuendet, M. A., and Michielin, O.
(2021). Turning tumors from cold to inflamed to improve immunotherapy response.
Cancer Treat. Rev. 101, 102227. doi:10.1016/j.ctrv.2021.102227
Ghosh, S., Brown, A. M., Jenkins, C., and Campbell, K. (2020). Viral vector systems
for gene therapy: a comprehensive literature review of progress and biosafety challenges.
Appl. Biosaf. 25 (1), 7–18. doi:10.1177/1535676019899502
Frontiers in Molecular Biosciences frontiersin.org14
Moaveni et al. 10.3389/fmolb.2024.1382190
Giacca, M., and Zacchigna, S. (2012). Virus-mediated gene delivery for human gene
therapy. J. Control Release 161 (2), 377–388. doi:10.1016/j.jconrel.2012.04.008
Gore, M. E. (2003). Adverse effects of gene therapy: gene therapy can caus e leukaemia:
no shock, mild horror but a probe. Gene Ther. 10 (1), 4. doi:10.1038/sj.gt.3301946
Gregory, G. L., and Copple, I. M. (2023). Modulating the expression of tumor
suppressor genes using activating oligonucleotide technologies as a therapeutic
approach in cancer. Mol. Ther. Nucleic Acids 31, 211–223. doi:10.1016/j.omtn.2022.
12.016
Greinix, H. T. (2019). Role of CAR-T cell therapy in B-cell acute lymphoblastic
leukemia. memo - Mag. Eur. Med. Oncol. 13 (1), 36–42. doi:10.1007/s12254-019-
00541-8
Grimley, M., Asnani, M., Shrestha, A., Felker, S., Lutzko, C., Arumugam, P. I., et al.
(2020). Early results from a phase 1/2 study of aru-1801 gene therapy for sickle cell
disease (SCD): manufacturing process enhancements improve efficacy of a modified
gamma globin lentivirus vector and reduced intensity conditioning transplant. Blood
136 (Suppl. 1), 20–21. doi:10.1182/blood-2020-140963
Gruszka, R., Zakrzewski, K., Liberski, P. P., and Zakrzewska, M. (2021). mRNA and
miRNA expression analyses of the MYC/E2F/miR-17-92 network in the most common
pediatric brain tumors. Int. J. Mol. Sci. 22 (2), 543. doi:10.3390/ijms22020543
Guan, J., Hallberg, B., and Palmer, R. H. (2021). Chromosome imbalances in
neuroblastoma-recent molecular insight into chromosome 1p-deletion, 2p-gain, and
11q-deletion identifies new friends and foes for the future. Cancers (Basel) 13 (23), 5897.
doi:10.3390/cancers13235897
Guo, C., Ma, X., Gao, F., and Guo, Y. (2023). Off-target effects in CRISPR/Cas9 gene
editing. Front. Bioeng. Biotechnol. 11, 1143157. doi:10.3389/fbioe.2023.1143157
Ha, T. C., Stahlhut, M., Rothe, M., Paul, G., Dziadek, V., Morgan, M., et al. (2021).
Multiple genes surrounding bcl-x
L
, a common retroviral insertion site, can influence
hematopoiesis individually or in concert. Hum. Gene Ther. 32 (9-10), 458–472. doi:10.
1089/hum.2019.344
Hacker, U. T., Bentler, M., Kaniowska, D., Morgan, M., and Buning, H. (2020).
Towards clinical implementation of adeno-associated virus (AAV) vectors for cancer
gene therapy: current status and future perspectives. Cancers (Basel) 12 (7), 1889. doi:10.
3390/cancers12071889
Handgretinger, R., and Schlegel, P. (2018). Emerging role of immunotherapy for
childhood cancers. Chin. Clin. Oncol. 7 (2), 14. doi:10.21037/cco.2018.04.06
Hao, L., Pu, X., and Song, J. (2021). Introduction of mutations in plants with prime
editing. Methods 194, 83–93. doi:10.1016/j.ymeth.2021.03.014
Harris, D. T., and Kranz, D. M. (2016). Adoptive T cell therapies: a comparison of
T cell receptors and chimeric antigen receptors. Trends Pharmacol. Sci. 37 (3), 220–230.
doi:10.1016/j.tips.2015.11.004
He, Y., de Araujo Junior, R. F., Cruz, L. J., and Eich, C. (2021). Functionalized
nanoparticles targeting tumor-associated macrophages as cancer therapy.
Pharmaceutics 13 (10), 1670. doi:10.3390/pharmaceutics13101670
He, Z., and Jia, X. (2020). Gene therapy (Part II). Therapy 20 (2), 83. doi:10.2174/
156652322002200821100006
Heyman, B. M., Tzachanis, D., and Kipps, T. J. (2022). Obinutuzumab, high-dose
methylprednisolone (HDMP), and lenalidomide for the treatment of patients with
richter’s syndrome. Cancers (Basel) 14 (7), 6035. doi:10.3390/cancers14246035
Hinterleitner, C., Strahle, J., Malenke, E., Hinterleitner, M., Henning, M., Seehawer,
M., et al. (2021). Platelet PD-L1 reflects collective intratumoral PD-L1 expression and
predicts immunotherapy response in non-small cell lung cancer. Nat. Commun. 12 (1),
7005. doi:10.1038/s41467-021-27303-7
Hintz, H. M., Snyder, K. M., Wu, J., Hullsiek, R., Dahlvang, J. D., Hart, G. T., et al.
(2021). Simultaneous engagement of tumor and stroma targeting antibodies by
engineered NK-92 cells expressing CD64 controls prostate cancer growth. Cancer
Immunol. Res. 9 (11), 1270–1282. doi:10.1158/2326-6066.CIR-21-0178
Hirshoren, N., Yoeli, R., Cohen, J. E., Weinberger, J. M., Kaplan, N., Merims, S., et al.
(2020). Checkpoint inhibitors: better outcomes among advanced cutaneous head and
neck melanoma patients. PLoS One 15 (4), e0231038. doi:10.1371/journal.pone.0231038
Hu, X., Li, L., Lu, Y., Yu, X., Chen, H., Yin, Q., et al. (2018). miRNA-21 inhibition
inhibits osteosarcoma cell proliferation by targeting PTEN and regulating the TGF-β1
signaling pathway. Oncol. Lett. 16 (4), 4337–4342. doi:10.3892/ol.2018.9177
Huang, M., Deng, J., Gao, L., and Zhou, J. (2020). Innovative strategies to advance
CAR T cell therapy for solid tumors. Am. J. Cancer Res. 10 (7), 1979–1992.
Hunger, S. P., Lu, X., Devidas, M., Camitta, B. M., Gaynon, P. S., Winick, N. J., et al.
(2012). Improved survival for children and adolescents with acute lymphoblastic
leukemia between 1990 and 2005: a report from the children’s oncology group.
J. Clin. Oncol. 30 (14), 1663–1669. doi:10.1200/JCO.2011.37.8018
Indersie, E., Lesjean, S., Hooks, K. B., Sagliocco, F., Ernault, T., Cairo, S., et al. (2017).
MicroRNA therapy inhibits hepatoblastoma growth in vivo by targeting β-catenin and
Wnt signaling. Hepatol. Commun. 1 (2), 168–183. doi:10.1002/hep4.1029
Ishihara, K., Goto, Y., and Matsuno, R. (2011). Biomimetic polymer nanoparticles
embedding quantum dots. MRS Proc. 1357. doi:10.1557/opl.2011.1505
Ita, K. (2020). Polyplexes for gene and nucleic acid delivery: progress and bottlenecks.
Eur. J. Pharm. Sci. 150, 105358. doi:10.1016/j.ejps.2020.105358
Jacobson, S. G., Cideciyan, A. V., Ho, A. C., Peshenko, I. V., Garafalo, A. V., Roman,
A. J., et al. (2021). Safety and improved efficacy signals following gene therapy in
childhood blindness caused by GUCY2D mutations. iScience 24 (5), 102409. doi:10.
1016/j.isci.2021.102409
Jain, H., Sengar, M., Goli, V. B., Thorat, J., Tembhare, P., Shetty, D., et al. (2021).
Bortezomib and rituximab in de novo adolescent/adult CD20-positive, Ph-negative pre-
B-cell acute lymphoblastic leukemia. Blood Adv. 5 (17), 3436–3444. doi:10.1182/
bloodadvances.2020003368
Jeong, S. G., Ryu, Y. C., and Hwang, B. H. (2021). Synergistic gene delivery by self-
assembled nanocomplexes using fusion peptide and calcium phosphate. J. Control
Release 338, 284–294. doi:10.1016/j.jconrel.2021.08.034
Jessa, S., Blanchet-Cohen, A., Krug, B., Vladoiu, M., Coutelier, M., Faury, D., et al.
(2019). Stalled developmental programs at the root of pediatric brain tumors. Nat.
Genet. 51 (12), 1702–1713. doi:10.1038/s41588-019-0531-7
J, G., S, G., and M, L. (2015). Let-7 family miRNAs represent potential broad-
spectrum therapeutic molecules for human cancer. J. Genet. Syndromes Gene Ther. 06
(03). doi:10.4172/2157-7412.1000271
Ji, X., Liu, Y., Mei, F., Li, X., Zhang, M., Yao, B., et al. (2021). SPP1 overexpression is
associated with poor outcomes in ALK fusion lung cancer patients without receiving
targeted therapy. Sci. Rep. 11 (1), 14031. doi:10.1038/s41598-021-93484-2
Johnson, A. V. (2018). An update: genetic mutations and childhood cancers. J. Nurse
Pract. 14 (4), 230–237. doi:10.1016/j.nurpra.2017.08.016
Jones, D. T. W., Banito, A., Grunewald, T. G. P., Haber, M., Jager, N., Kool, M., et al.
(2019). Molecular characteristics and therapeutic vulnerabilities across paediatric solid
tumours. Nat. Rev. Cancer 19 (8), 420–438. doi:10.1038/s41568-019-0169-x
Karavolias, N. G., Horner, W., Abugu, M. N., and Evanega, S. N. (2021). Application
of gene editing for climate change in agriculture. Front. Sustain. Food Syst. 5. doi:10.
3389/fsufs.2021.685801
Kauer, J., Horner, S., Osburg, L., Muller, S., Marklin, M., Heitmann, J. S., et al. (2020).
Tocilizumab, but not dexamethasone, prevents CRS without affecting antitumor activity
of bispecific antibodies. J. Immunother. Cancer 8 (1), e000621. doi:10.1136/jitc-2020-
000621
Ke, M., Kang, L., Wang, L., Yang, S., Wang, Y., Liu, H., et al. (2021). CAR-T therapy
alters synthesis of platelet-activating factor in multiple myeloma patients. J. Hematol.
Oncol. 14 (1), 90. doi:10.1186/s13045-021-01101-6
Kelley, K., Verma, I., and Pierce, G. F. (2002). Gene therapy: reality or myth for the
global bleeding disorders community? Haemophilia 8 (3), 261–267. doi:10.1046/j.1365-
2516.2002.00646.x
Kesavan, G. (2023). Innovations in CRISPR-based therapies. Mol. Biotechnol. 65 (2),
138–145. doi:10.1007/s12033-021-00411-x
Khan, J., and Helman, L. J. (2016). Precision therapy for pediatric cancers. JAMA
Oncol. 2 (5), 575–577. doi:10.1001/jamaoncol.2015.5685
Kieran, M. W., Goumnerova, L., Manley, P., Chi, S. N., Marcus, K. J., Manzanera, A.
G., et al. (2019). Phase I study of gene-mediated cytotoxic immunotherapy with AdV-tk
as adjuvant to surgery and radiation for pediatric malignant glioma and recurrent
ependymoma. Neuro Oncol. 21 (4), 537–546. doi:10.1093/neuonc/noy202
Kilburn, L. B., and Packer, R. J. (2020). JNO special issue: an update on pediatric
neuro-oncology. J. Neurooncol 150 (1), 1–4. doi:10.1007/s11060-020-03560-2
Kim, H. S., Lee, J. W., Kang, D., Yu, H., Kim, Y., Kang, H., et al. (2021). Characteristics
of RAS pathway mutations in juvenile myelomonocytic leukaemia: a single-institution
study from Korea. Br. J. Haematol. 195 (5), 748–756. doi:10.1111/bjh.17861
Kirches, E., Sahm, F., Korshunov, A., Bluecher, C., Waldt, N., Kropf, S., et al. (2021).
Molecular profiling of pediatric meningiomas shows tumor characteristics distinct from
adult meningiomas. Acta Neuropathol. 142 (5), 873–886. doi:10.1007/s00401-021-
02351-x
Kirschner, J., and Cathomen, T. (2020). Gene therapy for monogenic inherited
disorders. Dtsch. Arztebl Int. 117 (51-52), 878–885. doi:10.3238/arztebl.2020.0878
Knight, S., Collins, M., and Takeuchi, Y. (2013). Insertional mutagenesis by retroviral
vectors: current concepts and methods of analysis. Curr. Gene Ther. 13 (3), 211–227.
doi:10.2174/1566523211313030006
Kochenderfer, J. N., Wilson, W. H., Janik, J. E., Dudley, M. E., Stetler-Stevenson, M.,
Feldman, S. A., et al. (2010). Eradication of B-lineage cells and regression of lymphoma
in a patient treated with autologous T cells genetically engineered to recognize CD19.
Blood 116 (20), 4099–4102. doi:10.1182/blood-2010-04-281931
Koyama, S., Coban, C., Aoshi, T., Horii, T., Akira, S., and Ishii, K. J. (2009). Innate
immune control of nucleic acid-based vaccine immunogenicity. Expert Rev. Vaccines 8
(8), 1099–1107. doi:10.1586/erv.09.57
Krokhotin, A., Du, H., Hirabayashi, K., Popov, K., Kurokawa, T., Wan, X., et al.
(2019). Computationally guided design of single-chain variable fragment improves
specificity of chimeric antigen receptors. Mol. Ther. Oncolytics 15, 30–37. doi:10.1016/j.
omto.2019.08.008
Frontiers in Molecular Biosciences frontiersin.org15
Moaveni et al. 10.3389/fmolb.2024.1382190
Kulkarni, S. A., and Feng, S. S. (2011). Effects of surface modification on delivery
efficiency of biodegradable nanoparticles across the blood-brain barrier. Nanomedicine
(Lond). 6 (2), 377–394. doi:10.2217/nnm.10.131
Labrosse, R., Chu, J., Armant, M., van der Spek, J., Miggelbrink, A., Fong, J., et al.
(2019). Outcome of hematopoietic stem cell gene therapy for wiskott-aldrich syndrome.
Blood 134 (Suppl. ment_1), 4629. doi:10.1182/blood-2019-126161
Laetsch, T. W., DuBois, S. G., Bender, J. G., Macy, M. E., and Moreno, L. (2021).
Opportunities and challenges in drug development for pediatric cancers. Cancer Discov.
11 (3), 545–559. doi:10.1158/2159-8290.CD-20-0779
Ledford, H. (2020). CRISPR treatment inserted directly into the body for first time.
Nature 579 (7798), 185. doi:10.1038/d41586-020-00655-8
Ledford, H., and Callaway, E. (2018). Pioneers of revolutionary CRISPR gene editing
win chemistry Nobel. Nature 586, 346–347. doi:10.1038/d41586-020-02765-9
Lestini, B. J., Sagnella, S. M., Xu, Z., Shive, M. S., Richter, N. J., Jayaseharan, J., et al.
(2002). Surface modification of liposomes for selective cell targeting in cardiovascular
drug delivery. J. Control Release 78 (1-3), 235–247. doi:10.1016/s0168-3659(01)00505-3
leukaemia (2022). World-first use of base-edited cells to treat ‘incurable’leukaemia.
Levy, H. C., Hulvey, D., Adamson-Small, L., Jn-Simon, N., Prima, V., Rivkees, S., et al.
(2020). Improved cell-specificity of adeno-associated viral vectors for medullary thyroid
carcinoma using calcitonin gene regulatory elements. PLoS One 15 (2), e0228005.
doi:10.1371/journal.pone.0228005
Li, J., Xiang, M., Zhang, R., Xu, B., and Hu, W. (2018). RNA interference in vivo in
Schistosoma japonicum: establishing and optimization of RNAi mediated suppression
of gene expression by long dsRNA in the intra-mammalian life stages of worms.
Biochem. Biophys. Res. Commun. 503 (2), 1004–1010. doi:10.1016/j.bbrc.2018.06.109
Li, M. (2018). Enzyme replacement therapy: a review and its role in treating lysosomal
storage diseases. Pediatr. Ann. 47 (5), e191–e197. doi:10.3928/19382359-20180424-01
Li, H., Heath, J. E., Trippett, J. S., Shapiro, M. G., and Szablowski, J. O. (2021).
Engineering viral vectors for acoustically targeted gene delivery. bioRxiv 27. doi:10.
1101/2021.07.26.453904
Li, Z., and Langhans, S. A. (2021). In vivo and ex vivo pediatric brain tumor models: an
overview. Front. Oncol. 11, 620831. doi:10.3389/fonc.2021.620831
Libutti, S. K. (2014). New horizons for cancer gene therapy. Cancer Gene Ther. 21 (1),
1. doi:10.1038/cgt.2013.80
Libutti, S. K. (2019). Recording 25 years of progress in cancer gene therapy. Cancer
Gene Ther. 26 (11-12), 345–346. doi:10.1038/s41417-019-0121-y
Licciardone, J. C., and Aryal, S. (2014). Clinical response and relapse in patients with
chronic low back pain following osteopathic manual treatment: results from the
OSTEOPATHIC Trial. Man. Ther. 19 (6), 541–548. doi:10.1016/j.math.2014.05.012
Lin, G., Revia, R. A., and Zhang, M. (2021). Inorganic nanomaterial-mediated gene
therapy in combination with other antitumor treatment modalities. Adv. Funct. Mater
31 (5), 2007096. doi:10.1002/adfm.202007096
Liu, J., Xu, M., Yuan, Z., Tang, R., and Zhou, W. (2020). Highly efficient synthesis of
carbon-based molybdenum phosphide nanoparticles for electrocatalytic hydrogen
evolution. BIO Integr. 1 (1), 6–14. doi:10.1186/s11671-020-3246-x
Liu, P., Chen, G., and Zhang, J. (2022). A review of liposomes as a drug delivery
system: current status of approved products, regulatory environments, and future
perspectives. Molecules 27 (4), 1372. doi:10.3390/molecules27041372
Long, N., Gianola, D., Rosa, G. J., and Weigel, K. A. (2011). Long-term impacts of
genome-enabled selection. J. Appl. Genet. 52 (4), 467–480. doi:10.1007/s13353-011-
0053-1
Lugin, M. L., Lee, R. T., and Kwon, Y. J. (2020). Synthetically engineered adeno-
associated virus for efficient, safe, and versatile gene therapy applications. ACS Nano 14
(11), 14262–14283. doi:10.1021/acsnano.0c03850
Luis, A. (2020). The old and the new: prospects for non-integrating lentiviral vector
technology. Viruses 12 (10), 1103. doi:10.3390/v12101103
Ma, N., Ma, C., Li, C., Wang, T., Tang, Y., Wang, H., et al. (2013). Influence of
nanoparticle shape, size, and surface functionalization on cellular uptake. J. Nanosci.
Nanotechnol. 13 (10), 6485–6498. doi:10.1166/jnn.2013.7525
Ma, S., Li, X., Wang, X., Cheng, L., Li, Z., Zhang, C., et al. (2019). Current progress in
CAR-T cell therapy for solid tumors. Int. J. Biol. Sci. 15 (12), 2548–2560. doi:10.7150/
ijbs.34213
Mac Gabhann, F., Annex, B. H., and Popel, A. S. (2010). Gene therapy from the
perspective of systems biology. Curr. Opin. Mol. Ther. 12 (5), 570–577.
Magnani, C. F., Tettamanti, S., Maltese, F., Turazzi, N., Biondi, A., and Biagi, E.
(2013). Advanced targeted, cell and gene-therapy approaches for pediatric
hematological malignancies: results and future perspectives. Front. Oncol. 3, 106.
doi:10.3389/fonc.2013.00106
Mahase, E. (2021). NHS England agrees deal for gene therapy for spinal muscular
atrophy. BMJ 372, n653. doi:10.1136/bmj.n653
Mahata, B., Pramanik, J., van der Weyden, L., Polanski, K., Kar, G., Riedel, A., et al.
(2020). Tumors induce de novo steroid biosynthesis in T cells to evade immunity. Nat.
Commun. 11 (1), 3588. doi:10.1038/s41467-020-17339-6
Martinez, C., Yunis, L. K., Cabrera, E., García, J., Uribe, G., Quintero, E., et al. (2022).
Association between early risk factors and CDKN2A/B deletion in pediatric patients
with acute lymphoblastic leukemia in a pediatric cancer center in Colombia. Pediatr.
Hematol. Oncol. J. 7 (1), 1–3. doi:10.1016/j.phoj.2022.03.001
Maude, S. L., Laetsch, T. W., Buechner, J., Rives, S., Boyer, M., Bittencourt, H., et al.
(2018). Tisagenlecleucel in children and young adults with B-cell lymphoblastic
leukemia. N. Engl. J. Med. 378 (5), 439–448. doi:10.1056/NEJMoa1709866
Melamed, J. R., Hajj, K. A., Chaudhary, N., Strelkova, D., Arral , M. L., Pardi, N., et al.
(2022). Lipid nanoparticle chemistry determines how nucleoside base modifications
alter mRNA delivery. J. Control Release 341, 206–214. doi:10.1016/j.jconrel.2021.11.022
Mendez, C., Ahlenstiel, C. L., and Kelleher, A. D. (2015). Post-transcriptional gene
silencing, transcriptional gene silencing and human immunodeficiency virus. World
J. Virol. 4 (3), 219–244. doi:10.5501/wjv.v4.i3.219
Michalakis, S., Gerhardt, M., Rudolph, G., Priglinger, S., and Priglinger, C. (2021).
Gene therapy for inherited retinal disorders: update on clinical trials. Klin. Monbl
Augenheilkd 238 (3), 272–281. doi:10.1055/a-1384-0818
Millen, G. C., and Yap, C. (2021). Adaptive trial designs: what is the continual
reassessment method? Arch. Dis. Child. Educ. Pract. Ed. 106 (3), 175–177. doi:10.1136/
archdischild-2019-316931
Morgan, R. A., Dudley, M. E., Wunderlich, J. R., Hughes, M. S., Yang, J. C., Sherry, R.
M., et al. (2006). Cancer regression in patients after transfer of genetically engineered
lymphocytes. Science 314 (5796), 126–129. doi:10.1126/science.1129003
Morrissey, D., van Pijkeren, J. P., Rajendran, S., Collins, S. A., Casey, G., O’Sullivan, G.
C., et al. (2012). Control and augmentation of long-term plasmid transgene expression
in vivo in murine muscle tissue and ex vivo in patient mesenchymal tissue. J. Biomed.
Biotechnol. 2012, 379845. doi:10.1155/2012/379845
Moscoso, C. G., and Steer, C. J. (2019). Liver targeted gene therapy: insights into
emerging therapies. Drug Discov. Today Technol. 34, 9–19. doi:10.1016/j.ddtec.2020.
11.001
Muller, Y. D., Nguyen, D. P., Ferreira, L. M. R., Ho, P., Raffin, C., Valencia, R. V. B.,
et al. (2021). The CD28-transmembrane domain mediates chimeric antigen receptor
heterodimerization with CD28. Front. Immunol. 12, 639818. doi:10.3389/fimmu.2021.
639818
Murray, J. C., Aldeghaither, D., Wang, S., Nasto, R. E., Jablonski, S. A., Tang, Y., et al.
(2014). c-Abl modulates tumor cell sensitivity to antibody-dependent cellular cytotoxicity.
Cancer Immunol. Res. 2 (12), 1186–1198. doi:10.1158/2326-6066.CIR-14-0083
Musale, S., and Giram, P. (2021). Nose to brain delivery: role of viral and non-viral
vectors for neurological disorder. Indian Drugs 58 (05), 7–20. doi:10.53879/id.58.05.
12489
Napolitano, S., Ottaviano, G., Bettini, L., Russotto, V., Bonanomi, S., Rovelli, A., et al.
(2022). Cytokine release syndrome after CAR infusion in pediatric patients with
refractory/relapsed B-ALL: is there a role for diclofenac? Tumori 108 (6), 556–562.
doi:10.1177/03008916211053382
Narayanan, G. (2016). Translation and reimbursement: the twin challenges for cell
and gene therapies reflections of an ex-regulator. Hum. Gene Ther. Clin. Dev. 27 (3),
93–95. doi:10.1089/humc.2016.093
Narbona, J., Hernandez-Baraza, L., Gordo, R. G., Sanz, L., and Lacadena, J. (2023).
Nanobody-Based EGFR-targeting immunotoxins for colorectal cancer treatment.
Biomolecules 13 (7), 1042. doi:10.3390/biom13071042
Nastiuk, K. L., and Krolewski, J. J. (2016). Opportunities and challenges in
combination gene cancer therapy. Adv. Drug Deliv. Rev. 98, 35–40. doi:10.1016/j.
addr.2015.12.005
Neil, K., Allard, N., Roy, P., Grenier, F., Menendez, A., Burrus, V., et al. (2021). High-
efficiency delivery of CRISPR-Cas9 by engineered probiotics enables precise
microbiome editing. Mol. Syst. Biol. 17 (10), e10335. doi:10.15252/msb.202110335
Nelson, C. P., Lai, F. Y., Nath, M., Ye, S., Webb, T. R., Schunkert, H., et al. (2019).
Genetic assessment of potential long-term on-target side effects of PCSK9 (proprotein
convertase subtilisin/kexin type 9) inhibitors. Circ. Genom Precis. Med. 12 (1), e002196.
doi:10.1161/CIRCGEN.118.002196
Newman, S., Nakitandwe, J., Kesserwan, C. A., Azzato, E. M., Wheeler, D. A., Rusch,
M., et al. (2021). Genomes for kids: the scope of pathogenic mutations in pediatric
cancer revealed by comprehensive DNA and RNA sequencing. Cancer Discov. 11 (12),
3008–3027. doi:10.1158/2159-8290.CD-20-1631
Ngoune, R., Contini, C., Hoffmann, M. M., von Elverfeldt, D., Winkler, K., and Putz,
G. (2018). Optimizing antitumor efficacy and adverse effects of pegylated liposomal
doxorubicin by scheduled plasmapheresis: impact of timing and dosing. Curr. Drug
Deliv. 15 (9), 1261–1270. doi:10.2174/1567201815666180518125839
Noel, E. A., Weeks, D. P., and Van Etten, J. L. (2021). Pursuit of chlorovirus genetic
transformation and CRISPR/Cas9-mediated gene editing. PLoS One 16 (10), e0252696.
doi:10.1371/journal.pone.0252696
Nowicki, T. S., Anderson, J. L., and Federman, N. (2016). Prospective
immunotherapies in childhood sarcomas: PD1/PDL1 blockade in combination with
tumor vaccines. Pediatr. Res. 79 (3), 371–377. doi:10.1038/pr.2015.246
Oberlick, E. M., Rees, M. G., Seashore-Ludlow, B., Vazquez, F., Nelson, G. M., Dharia,
N. V., et al. (2019). Small-Molecule and CRISPR screening converge to reveal receptor
Frontiers in Molecular Biosciences frontiersin.org16
Moaveni et al. 10.3389/fmolb.2024.1382190
tyrosine kinase dependencies in pediatric rhabdoid tumors. Cell. Rep. 28 (9), 2331–2344.
doi:10.1016/j.celrep.2019.07.021
Organization (2021). CureAll framework: WHO global initiative for childhood
cancer: increasing access, advancing quality, saving lives. World Health Organ.
Pan, X., Veroniaina, H., Su, N., Sha, K., Jiang, F., Wu, Z., et al. (2021). Applications
and developments of gene therapy drug delivery systems for genetic diseases. Asian
J. Pharm. Sci. 16 (6), 687–703. doi:10.1016/j.ajps.2021.05.003
Pascual-Pasto, G., Bazan-Peregrino, M., Olaciregui, N. G., Restrepo-Perdomo, C. A.,
Mato-Berciano, A., Ottaviani, D., et al. (2019). Therapeutic targeting of the
RB1 pathway in retinoblastoma with the oncolytic adenovirus VCN-01. Sci. Transl.
Med. 11 (476), eaat9321. doi:10.1126/scitranslmed.aat9321
Pasquier, D., Lacornerie, T., Mirabel, X., Brassart, C., Vanquin, L., and Lartigau, E.
(2019). Stereotactic body radiotherapy. How to better protect normal tissues? Cancer
Radiother. 23 (6-7), 630–635. doi:10.1016/j.canrad.2019.07.153
Pearl, P. L., Tokatly, L. I., Lee, H. H. C., and Rotenberg, A. (2023). New therapeutic
approaches to inherited metabolic pediatric epilepsies. Neurology 101 (3), 124–133.
doi:10.1212/WNL.0000000000207133
Peltomaki, P. (2012). Mutations and epimutations in the origin of cancer. Exp. Cell.
Res. 318 (4), 299–310. doi:10.1016/j.yexcr.2011.12.001
Pettinato, M. C. (2021). Introduction to antibody-drug conjugates. Antibodies (Basel)
10 (4), 42. doi:10.3390/antib10040042
Piperno, A., Sciortino, M. T., Giusto, E., Montesi, M., Panseri, S., and Scala, A. (2021).
Recent advances and challenges in gene delivery mediated by polyester-based
nanoparticles. Int. J. Nanomedicine 16, 5981–6002. doi:10.2147/IJN.S321329
Poletti, V., and Mavilio, F. (2018). Interactions between retroviruses and the host cell
genome. Mol. Ther. Methods Clin. Dev. 8, 31–41. doi:10.1016/j.omtm.2017.10.001
Poli, F. E., Yusuf, I. H., Clouston, P., Shanks, M., Whitfield, J., Charbel Issa, P., et al.
(2023). MERTK missense variants in three patients with retinitis pigmentosa.
Ophthalmic Genet. 44 (1), 74–82. doi:10.1080/13816810.2022.2113541
Pomella, S., and Rota, R. (2020). The CRISP(Y) future of pediatric soft tissue
sarcomas. Front. Chem. 8, 178. doi:10.3389/fchem.2020.00178
Pscherer, A., Schliwka, J., Wildenberger, K., Mincheva, A., Schwaenen, C., Dohner,
H., et al. (2006). Antagonizing inactivated tumor suppressor genes and activated
oncogenes by a versatile transgenesis system: application in mantle cell lymphoma.
FASEB J. 20 (8), 1188–1190. doi:10.1096/fj.05-4854fje
Qasim, W., and Gkazi, S. A. (2019). Quantifying CRISPR off-target effects. Emerg.
Top. Life Sci. 3 (3), 327–334. doi:10.1042/ETLS20180146
Qu, Y., Siegler, E., Cheng, C., Liu, J., Cinay, G., Bagrodia, N., et al. (2019). Engineering
CAR-expressing natural killer cells with cytokine signaling and synthetic switch for an
off-the-shelf cell-based cancer immunotherapy. MRS Commun. 9 (2), 433–440. doi:10.
1557/mrc.2019.31
Rainey, G. J., and Coffin, J. M. (2006). Evolution of broad host range in retroviruses
leads to cell death mediated by highly cytopathic variants. J. Virol. 80 (2), 562–570.
doi:10.1128/JVI.80.2.562-570.2006
Raper, S. E., Chirmule, N., Lee, F. S., Wivel, N. A., Bagg, A., Gao, G. P., et al. (2003).
Fatal systemic inflammatory response syndrome in a ornithine transcarbamylase
deficient patient following adenoviral gene transfer. Mol. Genet. Metab. 80 (1-2),
148–158. doi:10.1016/j.ymgme.2003.08.016
Ren, S., Wang, M., Wang, C., Wang, Y., Sun, C., Zeng, Z., et al. (2021). Application of
non-viral vectors in drug delivery and gene therapy. Polym. (Basel) 13 (19), 3307. doi:10.
3390/polym13193307
Rex, T. S. (2015). Gene therapy to treat inherited and complex retinal degenerative
diseases. Mol. Ther. Methods Clin. Dev. 2, 15027. doi:10.1038/mtm.2015.27
Rizwanullah, M., Ahmad, M. Z., Ghoneim, M. M., Alshehri, S., Imam, S. S., Md, S.,
et al. (2021). Receptor-Mediated targeted delivery of surface-ModifiedNanomedicine in
breast cancer: recent update and challenges. Pharmaceutics 13 (12), 2039. doi:10.3390/
pharmaceutics13122039
Rocha, L. F. M., Braga, L. A. M., and Mota, F. B. (2020). Gene editing for treatment
and prevention of human diseases: a global survey of gene editing-related researchers.
Hum. Gene Ther. 31 (15-16), 852–862. doi:10.1089/hum.2020.136
Roy, B., Ghose, S., and Biswas, S. (2022). Therapeutic strategies for miRNA delivery to
reduce hepatocellular carcinoma. Semin. Cell. Dev. Biol. 124, 134–144. doi:10.1016/j.
semcdb.2021.04.006
RTS (2023). A study of ad-RTS-hIL-12 + veledimex in pediatric subjects with brain
tumors including DIPG.
Ruan, Y., Wang, H., Chen, B., Wen, H., and Wu, C. I. (2020). Mutations beget more
mutations-rapid evolution of mutation rate in response to the risk of runaway
accumulation. Mol. Biol. Evol. 37 (4), 1007–1019. doi:10.1093/molbev/msz283
Rubeis, G., and Steger, F. (2018). Risks and benefits of human germline genome
editing: an ethical analysis. Asian Bioeth. Rev. 10 (2), 133–141. doi:10.1007/s41649-018-
0056-x
Ruggero, K., Al-Assar, O., Chambers, J. S., Codrington, R., Brend, T., and Rabbitts, T.
H. (2016). LMO2 and IL2RG synergize in thymocytes to mimic the evolution of SCID-
X1 gene therapy-associated T-cell leukaemia. Leukemia 30 (9), 1959–1962. doi:10.1038/
leu.2016.116
Sabatino, D. E., Bushman, F. D., Chandler, R. J., Crystal, R. G., Davidson, B. L.,
Dolmetsch, R., et al. (2022). Evaluating the state of the science for adeno-associated
virus integration: an integrated perspective. Mol. Ther. 30 (8), 2646–2663. doi:10.1016/j.
ymthe.2022.06.004
Safari, F., Rahmani Barouji, S., and Tamaddon, A. M. (2017). Strategies for improving
siRNA-induced gene silencing efficiency. Adv. Pharm. Bull. 7 (4), 603–609. doi:10.
15171/apb.2017.072
Safarzadeh Kozani, P., Safarzadeh Kozani, P., and Rahbarizadeh, F. (2021a).
Aptamer-assisted delivery of nucleotides with tumor-suppressing properties for
targeted cancer therapies. Trends Med. Sci. 1 (4). doi:10.5812/tms.114909
Safarzadeh Kozani, P., Safarzadeh Kozani, P., and Rahbarizadeh, F. (2021b).
Optimizing the clinical impact of CAR-T cell therapy in B-cell acute lymphoblastic
leukemia: looking back while moving forward. Front. Immunol. 12, 765097. doi:10.
3389/fimmu.2021.765097
Sakuma, T., Hosoi, S., Woltjen, K., Suzuki, K., Kashiwagi, K., Wada, H., et al. (2013).
Efficient TALEN construction and evaluation methods for human cell and animal
applications. Genes. cells. 18 (4), 315–326. doi:10.1111/gtc.12037
Sasaki, K., Harada, M., Miyashita, Y., Tagawa, H., Kishimura, A., Mori, T., et al.
(2020). Fc-binding antibody-recruiting molecules exploit endogenous antibodies for
anti-tumor immune responses. Chem. Sci. 11 (12), 3208–3214. doi:10.1039/d0sc00017e
Schreurs, J., Sacchetto, C., Colpaert, R. M. W., Vitiello, L., Rampazzo, A., and Calore,
M. (2021). Recent advances in CRISPR/Cas9-Based genome editing tools for cardiac
diseases. Int. J. Mol. Sci. 22 (20), 10985. doi:10.3390/ijms222010985
Schulte,J.H.,andEggert,A.(2021).ALKinhibitors in neuroblastoma: a sprint from bench
to bedside. Clin. Cancer Res. 27 (13), 3507–3509. doi:10.1158/1078-0432.CCR-21-0627
Schutz, F., Stefanovic, S., Mayer, L., von Au, A., Domschke, C., and Sohn, C. (2017).
PD-1/PD-L1 pathway in breast cancer. Oncol. Res. Treat. 40 (5), 294–297. doi:10.1159/
000464353
Senft, D., Leiserson, M. D. M., Ruppin, E., and Ronai, Z. A. (2017). Precision
oncology: the road ahead. Trends Mol. Med. 23 (10), 874–898. doi:10.1016/j.
molmed.2017.08.003
Shaw, A. R., and Suzuki, M. (2019). Immunology of adenoviral vectors in cancer
therapy. Mol. Ther. Methods Clin. Dev. 15, 418–429. doi:10.1016/j.omtm.2019.11.001
Shi, Z. D., Tchao, J., Wu, L., and Carman, A. J. (2020). Precision installation of a highly
efficient suicide gene safety switch in human induced pluripotent stem cells. Stem Cells
Transl. Med. 9 (11), 1378–1388. doi:10.1002/sctm.20-0007
Smirnov, S., Petukhov, A., Levchuk, K., Kulemzin, S., Staliarova, A., Lepik, K., et al.
(2021). Strategies to circumvent the side-effects of immunotherapy using allogeneic
CAR-T cells and boost its efficacy: results of recent clinical trials. Front. Immunol. 12,
780145. doi:10.3389/fimmu.2021.780145
Smith, L. M., Ladner, J. T., Hodara, V. L., Parodi, L. M., Harris, R. A., Callery, J. E.,
et al. (2021). Multiplexed simian immunodeficiency virus-specific paired RNA-guided
Cas9 nickases inactivate proviral DNA. J. Virol. 95 (23), e0088221. doi:10.1128/JVI.
00882-21
Soldevilla, M. M., Villanueva, H., Meraviglia-Crivelli, D., Menon, A. P., Ruiz, M.,
Cebollero, J., et al. (2019). ICOS costimulation at the tumor site in combination with
CTLA-4 blockade therapy elicits strong tumor immunity. Mol. Ther. 27 (11),
1878–1891. doi:10.1016/j.ymthe.2019.07.013
Sole, A., Grossetete, S., Heintze, M., Babin, L., Zaidi, S., Revy, P., et al. (2021).
Unraveling ewing sarcoma tumorigenesis originating from patient-derived
mesenchymal stem cells. Cancer Res. 81 (19), 4994–5006. doi:10.1158/0008-5472.
CAN-20-3837
Spain, L., Diem, S., and Larkin, J. (2016). Management of toxicities of immune
checkpoint inhibitors. Cancer Treat. Rev. 44, 51–60. doi:10.1016/j.ctrv.2016.02.001
Steckbeck, J. D., Kuhlmann, A. S., and Montelaro, R. C. (2014). Structural and
functional comparisons of retroviral envelope protein C-terminal domains: still much to
learn. Viruses 6 (1), 284–300. doi:10.3390/v6010284
Straathof, K., Flutter, B., Wallace, R., Jain, N., Loka, T., Depani, S., et al. (2020).
Antitumor activity without on-target off-tumor toxicity of GD2-chimeric antigen
receptor T cells in patients with neuroblastoma. Sci. Transl. Med. 12 (571),
eabd6169. doi:10.1126/scitranslmed.abd6169
Sugapriya, D., Preethi, S., Shanthi, P., Chandra, N., Jeyaraman, G., Sachdanandam, P.,
et al. (2012). BCR-ABL translocation in pediatric acute lymphoblastic leukemia in
southern India. Indian J. Hematol. Blood Transfus. 28 (1), 37–41. doi:10.1007/s12288-
011-0096-9
Sun, Z., Fu, Y. X., and Peng, H. (2018). Targeting tumor cells with antibodies enhanc es
anti-tumor immunity. Biophys. Rep. 4 (5), 243–253. doi:10.1007/s41048-018-0070-2
Suresh, S. (2021). Beginner’s guide to CRISPR-Cas9-based gene editing. Biochem. 43
(4), 36–40. doi:10.1042/bio_2021_131
Swati, C. V. D. (2021). Role of epigenetic mechanisms in propagating off-targeted
effects following radiation based therapies - a review. Mutat. Res. Rev. Mutat. Res. 787,
108370. doi:10.1016/j.mrrev.2021.108370
Frontiers in Molecular Biosciences frontiersin.org17
Moaveni et al. 10.3389/fmolb.2024.1382190
Torres-Vanegas, J. D., Cruz, J. C., and Reyes, L. H. (2021). Delivery systems for nucleic
acids and proteins: barriers, cell capture pathways and nanocarriers. Pharmaceutics 13
(3), 428. doi:10.3390/pharmaceutics13030428
Treger, T. D., Chowdhury, T., Pritchard-Jones, K., and Behjati, S. (2019). The genetic
changes of Wilms tumour. Nat. Rev. Nephrol. 15 (4), 240–251. doi:10.1038/s41581-019-
0112-0
Trivedi, S., and Ferris, R. L. (2021). Epidermal growth factor receptor-targeted
therapy for head and neck cancer. Otolaryngol. Clin. North Am. 54 (4), 743–749.
doi:10.1016/j.otc.2021.04.005
Troyanovsky, B., Bitko, V., Fouty, B., and Solodushko, V. (2015). Simple viral/
minimal piggyBac hybrid vectors for stable production of self-inactivating gamma-
retroviruses. BMC Res. Notes 8, 379. doi:10.1186/s13104-015-1354-y
Tustian, A. D., and Bak, H. (2021). Assessment of quality attributes for adeno-
associated viral vectors. Biotechnol. Bioeng. 118 (11), 4186–4203. doi:10.1002/bit.27905
Upton, R., Banuelos, A., Feng, D., Biswas, T., Kao, K., McKenna, K., et al. (2021).
Combining CD47 blockade with trastuzumab eliminates HER2-positive breast cancer
cells and overcomes trastuzumab tolerance. Proc. Natl. Acad. Sci. U. S. A. 118 (29),
e2026849118. doi:10.1073/pnas.2026849118
Usui, Y., Miura, T., Kawaguchi, T., Kosugi, K., Uehara, Y., Kato, M., et al. (2022).
Palliative care physicians’recognition of patients after immune checkpoint inhibitors
and immune-related adverse events. Support Care Cancer 30 (1), 775–784. doi:10.1007/
s00520-021-06482-5
van der Koog, L., Gandek, T. B., and Nagelkerke, A. (2022). Liposomes and
extracellular vesicles as drug delivery systems: a comparison of composition,
pharmacokinetics, and functionalization. Adv. Healthc. Mater 11 (5), e2100639.
doi:10.1002/adhm.202100639
van Tetering, G., Evers, M., Chan, C., Stip, M., and Leusen, J. (2020). Fc engineering
strategies to advance IgA antibodies as therapeutic agents. Antibodies (Basel) 9 (4), 70.
doi:10.3390/antib9040070
Verreault, M., Webb, M. S., Ramsay, E. C., and Bally, M. B. (2006). Gene silencing in
the development of personalized cancer treatment: the targets, the agents and the
delivery systems. Curr. Gene Ther. 6 (4), 505–533. doi:10.2174/156652306777934838
Vitanza, N. A., Johnson, A. J., Wilson, A. L., Brown, C., Yokoyama, J. K., Kunkele, A.,
et al. (2021). Locoregional infusion of HER2-specific CAR T cells in children and young
adults with recurrent or refractory CNS tumors: an interim analysis. Nat. Med. 27 (9),
1544–1552. doi:10.1038/s41591-021-01404-8
Vollrath, D., Feng, W., Duncan, J. L., Yasumura, D., D’Cruz, P. M., Chappelow, A.,
et al. (2001). Correction of the retinal dystrophy phenotype of the RCS rat by viral gene
transfer of Mertk. Proc. Nat. Acad. Sci. 98 (22), 12584–12589.
Voynova, E., and Kovalovsky, D. (2021). From hematopoietic stem cell
transplantation to chimeric antigen receptor therapy: advances, limitations and
future perspectives. Cells 10 (11), 2845. doi:10.3390/cells10112845
Wang, H., Yin, X., and Wu, D. (2010). Novel human pathological mutations.
SLC34A2. Disease: pulmonary alveolar microlithiasis. Hum. Genet. 127 (4), 471.
doi:10.1007/s00439-010-0870-z
Wang, Z., Chen, W., Zhang, X., Cai, Z., and Huang, W. (2019). A long way to the
battlefront: CAR T cell therapy against solid cancers. J. Cancer 10 (14), 3112–3123.
doi:10.7150/jca.30406
Wedekind, M. F., Denton, N. L., Chen, C. Y., and Cripe, T. P. (2018). Pediatric cancer
immunotherapy: opportunities and challenges. Paediatr. Drugs 20 (5), 395–408. doi:10.
1007/s40272-018-0297-x
West, R. M., and Gronvall, G. K. (2020). CRISPR cautions: biosecurity implications of
gene editing. Perspect. Biol. Med. 63 (1), 73–92. doi:10.1353/pbm.2020.0006
Woods, N. B., Muessig, A., Schmidt, M., Flygare, J., Olsson, K., Salmon, P., et al.
(2003). Lentiviral vector transduction of NOD/SCID repopulating cells results in
multiple vector integrations per transduced cell: risk of insertional mutagenesis.
Blood 101 (4), 1284–1289. doi:10.1182/blood-2002-07-2238
Wu,S.,Lu,J.,Su,D.,Yang,F.,Zhang,Y.,andHu,S.(2021).Theadvantageofchimeric
antigen receptor T cell therapy in pediatric acute lymphoblastic leukemia with E2A-HLF
fusion gene positivity: a case series. Transl. Pediatr. 10 (3), 686–691. doi:10.21037/tp-20-323
Xia, Y., Li, X., and Sun, W. (2020). Applications of recombinant adenovirus-p53 gene
therapy for cancers in the clinic in China. Curr. Gene Ther. 20 (2), 127–141. doi:10.2174/
1566523220999200731003206
Xu, J., Meng, Q., Sun, H., Zhang, X., Yun, J., Li, B., et al. (2021). HER2-specific
chimeric antigen receptor-T cells for targeted therapy of metastatic colorectal cancer.
Cell. Death Dis. 12 (12), 1109. doi:10.1038/s41419-021-04100-0
Xu, P., Tong, Y., Liu, X. Z., Wang, T. T., Cheng, L., Wang, B. Y., et al. (2015). Both
TALENs and CRISPR/Cas9 directly target the HBB IVS2-654 (C >T) mutation in β-
thalassemia-derived iPSCs. Sci. Rep. 5, 12065. doi:10.1038/srep12065
Yahya, E. B., and Alqadhi, A. M. (2021). Recent trends in cancer therapy: a review on
the current state of gene delivery. Life Sci. 269, 119087. doi:10.1016/j.lfs.2021.119087
Yin, L., Zhao, F., Sun, H., Wang, Z., Huang, Y., Zhu, W., et al. (2020). CRIS PR-Cas13a
inhibits HIV-1 infection. Mol. Ther. Nucleic Acids 21, 147–155. doi:10.1016/j.omtn.
2020.05.030
Zapolnik, P., and Pyrkosz, A. (2021). Gene therapy for mucopolysaccharidosis type II-
A review of the current possibilities. Int. J. Mol. Sci. 22 (11), 5490. doi:10.3390/
ijms22115490
Zeng, B., Zhou, M., Liu, B., Shen, F., Xiao, R., Su, J., et al. (2021). Targeted addition of
mini-dystrophin into rDNA locus of Duchenne muscular dystrophy patient-derived
iPSCs. Biochem. Biophys. Res. Commun. 545, 40–45. doi:10.1016/j.bbrc.2021.01.056
Zhang, R., Xu, W., Shao, S., and Wang, Q. (2021b). Gene silencing through CRISPR
interference in bacteria: current advances and future prospects. Front. Microbiol. 12,
635227. doi:10.3389/fmicb.2021.635227
Zhang, W., Kong, X., Ai, B., Wang, Z., Wang, X., Wang, N., et al. (2021a). Research
progresses in immunological checkpoint inhibitors for breast cancer immunotherapy.
Front. Oncol. 11, 582664. doi:10.3389/fonc.2021.582664
Zhang, Z., Zhang, S., Huang, X., Orwig, K. E., and Sheng, Y. (2013). Rapid assembly of
customized TALENs into multiple delivery systems. PLoS One 8 (11), e80281. doi:10.
1371/journal.pone.0080281
Zhao, C. T., and Liu, Z. B. (2014). Application of gold nanoparticles in cancer therapy.
Zhongguo Yi Xue Ke Xue Yuan Xue Bao 36 (3), 324–329. doi:10.3881/j.issn.1000-503X.
2014.03.019
Zhao, G., Pu, J., and Tang, B. (2016). Applications of ZFN, TALEN and CRISPR/
Cas9 techniques in disease modeling and gene therapy. Zhonghua Yi Xue Yi Chuan Xue
Za Zhi 33 (6), 857–862. doi:10.3760/cma.j.issn.1003-9406.2016.06.025
Zhao, Z., Ukidve, A., Kim, J., and Mitragotri, S. (2020a). Targeting strategies for
tissue-specific drug delivery. Cell. 181 (1), 151–167. doi:10.1016/j.cell.2020.02.001
Zhao, Z., Xiao, X., Saw, P. E., Wu, W., Huang, H., Chen, J., et al. (2020b). Chimeric
antigen receptor T cells in solid tumors: a war against the tumor microenvironment. Sci.
China Life Sci. 63 (2), 180–205. doi:10.1007/s11427-019-9665-8
Zhou, Y. C., Zhang, Y. N., Yang, X., Wang, S. B., and Hu, P. Y. (2020). Delivery
systems for enhancing oncolytic adenoviruses efficacy. Int. J. Pharm. 591, 119971.
doi:10.1016/j.ijpharm.2020.119971
Zhu, C., Song, Z., Wang, A., Srinivasan, S., Yang, G., Greco, R., et al. (2020).
Isatuximab acts through fc-dependent, independent, and direct pathways to kill
multiple myeloma cells. Front. Immunol. 11, 1771. doi:10.3389/fimmu.2020.01771
Ziegler, T., Ishikawa, K., Hinkel, R., and Kupatt, C. (2018). Translational aspects of
adeno-associated virus-mediated cardiac gene therapy. Hum. Gene Ther. 29 (12),
1341–1351. doi:10.1089/hum.2017.229
Zohri, M., Arefian, E., Akbari Javar, H., Gazori, T., Aghaee-Bakhtiari, S. H., Taheri,
M., et al. (2021). Potential of chitosan/alginate nanoparticles as a non-viral vector for
gene delivery: formulation and optimization using D-optimal design. Mater Sci. Eng. C
Mater Biol. Appl. 128, 112262. doi:10.1016/j.msec.2021.112262
Frontiers in Molecular Biosciences frontiersin.org18
Moaveni et al. 10.3389/fmolb.2024.1382190
