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(a) Structure of siRNA; (b) siRNA pathway; (c) miRNA pathway (Reproduced with permission from [8]. Copyright the Royal Society of Chemistry, 2003).
Source publication
siRNA is a promising therapeutic solution to address gene overexpression or mutations as a post-transcriptional gene regulation process for several pathological conditions such as viral infections, cancer, genetic disorders, and autoimmune disorders like arthritis. This therapeutic method is currently being actively pursued in cancer therapy becaus...
Citations
... Oncogenes are genes that promote uncontrolled cell division (Yan et al., 2011). Gene therapy techniques can silence or inactivate oncogenes in cancer cells (Wendel et al., 2006;Poltronieri et al., 2013;Tatiparti et al., 2017). d. ...
Cancer is a significant global socioeconomic burden, as millions of new cases and deaths occur annually. In 2020, almost 10 million cancer deaths were recorded worldwide. Advancements in cancer gene therapy have revolutionized the landscape of cancer treatment. An approach with promising potential for cancer gene therapy is introducing genes to cancer cells that encode for chemotherapy prodrug metabolizing enzymes, such as Cytochrome P450 (CYP) enzymes, which can contribute to the effective elimination of cancer cells. This can be achieved through gene-directed enzyme prodrug therapy (GDEPT). CYP enzymes can be genetically engineered to improve anticancer prodrug conversion to its active metabolites and to minimize chemotherapy side effects by reducing the prodrug dosage. Rational design, directed evolution, and phylogenetic methods are some approaches to developing tailored CYP enzymes for cancer therapy. Here, we provide a compilation of genetic modifications performed on CYP enzymes aiming to build highly efficient therapeutic genes capable of bio-activating different chemotherapeutic prodrugs. Additionally, this review summarizes promising preclinical and clinical trials highlighting engineered CYP enzymes’ potential in GDEPT. Finally, the challenges, limitations, and future directions of using CYP enzymes for GDEPT in cancer gene therapy are discussed.
... Until today, various strategies have been developed for siRNA delivery, including inorganic nanoparticles (NPs), lipid nanoparticles (LNPs), adeno-associated viruses (AAVs), and cationic polymers. Still, few advances have been reported for targeted RNA delivery in the field of hematologic malignancies [6]. In addition to diminishing the side effects, an optimal NP should be able to carry large dosages of pharmacological agents, effectively target cancer cells, and shield the siRNA from destruction [7]. ...
Because of the high biocompatibility, self-assembly capability, and CD71-mediated endocytosis, using human heavy chain ferritin (HFn) as a nanocarrier would greatly increase therapeutic effectiveness and reduce possible adverse events. Anti-PD-L1 siRNA can downregulate the level of PD-L1 on tumor cells, resulting in the activation of effector T cells against leukemia. Therefore, this study aimed to produce the tumor-targeting siPD-L1/HFn nanocarrier. Briefly, the HFn coding sequence was cloned into a pET-28a, and the constructed expression plasmid was subsequently transformed into E. coli BL21. After induction of Isopropyl β-d-1-thiogalactopyranoside (IPTG), HFn was purified with Ni-affinity chromatography and dialyzed against PBS. The protein characteristics were analyzed using SDS-PAGE, Western Blot, and Dynamic light scattering (DLS). The final concentration was assessed using the Bicinchoninic acid (BCA) assay. The encapsulation was performed using the standard pH system. The treatment effects of siPD-L1/HFn were carried out on HL-60 and K-562 cancer cell lines. The RT-PCR was used to determine the mRNA expression of PD-L1. The biocompatibility and excretion of siPD-L1/HFn have also been evaluated. The expression and purity of HFn were well verified through SDS-PAGE, WB, and DLS. RT-PCR analyses also showed significant siRNA-mediated PD-L1 silencing in both HL-60 and K-562 cells. Our study suggested a promising approach for siRNA delivery. This efficient delivery system can pave the way for the co-delivery of siRNAs and multiple chemotherapies to address the emerging needs of cancer combination therapy.
... Some progress has been made to chemically modify siRNA, providing greater serum stability for systemic RNAi [8], but these advances do not address specific delivery to diseased tissue. The development of various nanoparticulate systems to package and deliver siRNA have been described [9,10], and by functionalising these systems it is possible to achieve some tissue tropism, particularly as therapeutics for hepatic diseases, including tumours of the liver. ...
Background
Bacterial cancer therapy was first trialled in patients at the end of the nineteenth century. More recently, tumour-targeting bacteria have been harnessed to deliver plasmid-expressed therapeutic interfering RNA to a range of solid tumours. A major limitation to clinical translation of this is the short-term nature of RNA interference in vivo due to plasmid instability. To overcome this, we sought to develop tumour-targeting attenuated bacteria that stably express shRNA by virtue of integration of an expression cassette within the bacterial chromosome and demonstrate therapeutic efficacy in vitro and in vivo.
Results
The attenuated tumour targeting Salmonella typhimurium SL7207 strain was modified to carry chromosomally integrated shRNA expression cassettes at the xylA locus. The colorectal cancer cell lines SW480, HCT116 and breast cancer cell line MCF7 were used to demonstrate the ability of these modified strains to perform intracellular infection and deliver effective RNA and protein knockdown of the target gene c-Myc . In vivo therapeutic efficacy was demonstrated using the Lgr5creER T2 Apc flx/flx and BlgCreBrca2 flx/fl p53 flx/flx orthotopic immunocompetent mouse models of colorectal and breast cancer, respectively. In vitro co-cultures of breast and colorectal cancer cell lines with modified SL7207 demonstrated a significant 50–95% ( P < 0.01) reduction in RNA and protein expression with SL7207/c-Myc targeted strains. In vivo, following establishment of tumour tissue, a single intra-peritoneal administration of 1 × 10 ⁶ CFU of SL7207/c-Myc was sufficient to permit tumour colonisation and significantly extend survival with no overt toxicity in control animals.
Conclusions
In summary we have demonstrated that tumour tropic bacteria can be modified to safely deliver therapeutic levels of gene knockdown. This technology has the potential to specifically target primary and secondary solid tumours with personalised therapeutic payloads, providing new multi-cancer detection and treatment options with minimal off-target effects. Further understanding of the tropism mechanisms and impact on host immunity and microbiome is required to progress to clinical translation.
... Second, endocytosis into cells alone is difficult due to the negative charge on the surface of siRNAs. siRNA-induced gene silencing in mammalian cells usually must be optimally designed or modified to successfully enter the mammalian cells using transfection, electroporation, or microinjection (Sufianov et al., 2023;Wu et al., 2018;Tatiparti et al., 2017). This differs from the primary route of exposure (ingestion or inhalation from plants) for RNAi-based biopesticides . ...
... 30 Targeting chromatin and histone-modifying genes can lead to significant changes in gene expression patterns and cellular processes through alterations in chromatin structure and histone modifications. Additionally, inhibition of protein synthesis can further exacerbate these effects by disrupting the regulation of these processes 31 (Fig. 2). There are some major limitations in the use of siRNA-based therapies including rapid degradation and renal clearance when it is administered systemically. ...
RNA therapy is one of the new treatments using small RNA molecules to target and regulate gene expression. It involves the application of synthetic or modified RNA molecules to inhibit the expression of disease-causing genes specifically. In other words, it silences genes and suppresses the transcription process. The main theory behind RNA therapy is that RNA molecules can prevent the translation into proteins by binding to specific messenger RNA (mRNA) molecules. By targeting disease-related mRNA molecules, RNA therapy can effectively silence or reduce the development of harmful proteins. There are different types of RNA molecules used in therapy, including small interfering RNAs (siRNAs), microRNAs (miRNAs), aptamer, ribozyme, and antisense oligonucleotides (ASOs). These molecules are designed to complement specific mRNA sequences, allowing them to bind and degrade the targeted mRNA or prevent its translation into protein. Nanotechnology is also highlighted to increase the efficacy of RNA-based drugs. In this chapter, while examining various methods of RNA therapy, we discuss the advantages and challenges of each.
... This innovative treatment approach is actively under investigation, particularly in the field of cancer treatment, where noncoding RNA has demonstrated its ability to suppress oncogenes and rectify mutations in tumor suppressor genes, shedding light on critical molecular pathways in cancer. Additionally, its adaptability, specificity, and wide applicability make it well-suited for personalized gene therapy for various diseases (Tatiparti et al. 2017). ...
... Notable examples of these include siRNA-EphA2-DOPC for the treatment of advanced solid tumors, TKM-080,301 for both primary and secondary liver cancer, and DCR-MYC for addressing solid tumors, multiple myeloma, and non-Hodgkin's lymphoma. These developments reflect a significant shift in the translational potential of siRNA-based therapies within the field of oncology (Tatiparti et al. 2017). ...
... Given that the most common delivery route of siRNA-based therapies is the intravenous administration, 57 it becomes necessary to understand what is the fate of the nanosystem as it comes into contact with elements in the bloodstream, such as plasma proteins. In particular, albumin has a polyanionic structure that could cause polyanionic exchange with siRNA. ...
This study focuses on designing hybrid theranostic nanosystems, utilizing gadolinium-doped carbon nanodots decorated with bioreducible amphoteric polyamidoamines (PAAs). The objective is to synergize the exceptional theranostic properties of gadolinium-doped carbon nanodots (CDs) with the siRNA complexation capabilities of PAAs. Linear copolymeric polyamidoamines, based on N,N′-bis(acryloyl)cystamine, arginine, and agmatine, were synthesized, resulting in three distinct amphoteric copolymers. Notably, sulfur bridges within the PAA repeating units confer pronounced susceptibility to glutathione-mediated degradation—a key attribute in the tumor microenvironment. This pathway enables controlled and stimuli-responsive siRNA release, theoretically providing precise spatiotemporal control over therapeutic interventions. The selected PAA, conjugated with CDs using the redox-sensitive spacer cystamine, formed the CDs-Cys-PAA conjugate with superior siRNA complexing capacity. Stable against polyanion exchange, the CDs-Cys-PAA/siRNA complex released siRNA in the presence of GSH. In vitro studies assessed cytocompatibility, internalization, and gene silencing efficacy on HeLa, MCF-7, and 16HBE cell lines.
... Furthermore, Qian et al. [104] demonstrated the enrichment of miR-1243p inside neural stem cell-derived exosomes (NSC-EXO) successfully transferred miR-1243p into glioma cells, leading to a significant prevention of glioma cell reproduction and invasion. As known, siRNA is a subclass of double-stranded DNA molecule that possesses the ability to modulate the production of target mRNA and hence treat a number of illnesses [105]. Aqil et al. [106] used the Exo-fect Exosome Transfection Reagent to transfect milk EXOs with siRNA targeting particular genes such EGFR, VEGF, MAPK, AKT, and KRAS. ...
During the past few decades, researchers have attempted to discover an effective treatment for cancer. Exosomes are natural nanovesicles released by various cells and play a role in communication between cells. While natural exosomes have high clinical potential, their inherent limitations have prompted researchers to design exosomes with improved therapeutic properties. To achieve this purpose, researchers have undertaken exosome engineering to modify the surface properties or internal composition of exosomes. After these modifications, engineered exosomes can be used as carriers for delivery of chemotherapeutic agents, targeted drug delivery or development of cancer vaccines. The present study provides an overview of exosomes, including their biogenesis, biological functions, isolation techniques, engineering methods, and potential applications in cancer therapy.
... A typical siRNA molecule consists of two strands, each 19 to 21 nucleotides in length, with 3' overhangs of two nucleotides on each strand, for a total duplex length of 21 to 23 base pairs. Besides, RNA-induced silencing complex (RISC) recognizes and breaks down the target transcript, resulting in silence and degradation of siRNA's 5'-terminal region [85,86]. After cleavage, the RISC-siRNA complex previously recycled may be employed in other cleavage processes. ...
Pancreatic cancer is one of the fatal malignancies, and the early stages of pancreatic cancer are symptomless. 60%–70% of pancreatic cancers originate in the pancreas, head, and neck. The diagnosis of pancreatic cancer is noticed too late, mainly in the metastatic phase for 75%–80% of patients, which is very difficult for the survival of the patients. The current treatment and diagnostic methods, such as chemotherapy, radiation therapy, surgical resection, CT scan, and MRI, are prevalent, but these approaches have various limitations and low survival rates. Nanotechnological approaches or nanoparticle drug delivery systems are potential tools for early diagnosis and better treatment. Solid lipid-based nanoparticles (SLNs) are very popular in various cancer treatments among various nanoparticle drug delivery systems. This chapter demonstrates the drug delivery through SLNs to pancreatic cancer, their synthesis techniques, and advantages of SLNs on pancreatic cancer.
... Moreover, the activated RISC-siRNA complex can be reactivated to target and eliminate additional mRNA molecules with identical sequences [72,215,216] translation machinery to express their own proteins, targeting virally encoded cytoplasmic mRNAs is a common strategy, at least in theory, to mitigate infection with viruses susceptible to inhibition [27]. Exogenous siRNAs, designed to mediate the degradation of viral RNA targets, are typically introduced into cells with synthetic or vector-based delivery systems [28]. ...
... RISC-mediates cleavage of virally encoded cytoplasmic mRNAs to inhibit virus replication. Exogenous siRNAs degrade viral RNAs via RNAi pathways [28]. As soon as the genome of a novel virus is identified, RNAi is a reliable infection-mitigating strategy. ...
... Cationic materials stabilize interactions and have well-defined polymer morphology, enabling cross-linking, and show promise for efficient siRNA delivery. Cationic lipids in liposomes can overcome the negative charges of siRNAs [28]. Stable nucleic acid lipid particles enhance siRNA stability and transport efficiency [96]. ...
RNA has emerged as a revolutionary and important tool in the battle against emerging infectious diseases, with roles extending beyond its applications in vaccines, in which it is used in the response to the COVID-19 pandemic. Since their development in the 1990s, RNA interference (RNAi) therapeutics have demonstrated potential in reducing the expression of disease-associated genes. Nucleic acid-based therapeutics, including RNAi therapies, that degrade viral genomes and rapidly adapt to viral mutations, have emerged as alternative treatments. RNAi is a robust technique frequently employed to selectively suppress gene expression in a sequence-specific manner. The swift adaptability of nucleic acid-based therapeutics such as RNAi therapies endows them with a significant advantage over other antiviral medications. For example, small interfering RNAs (siRNAs) are produced on the basis of sequence complementarity to target and degrade viral RNA, a novel approach to combat viral infections. The precision of siRNAs in targeting and degrading viral RNA has led to the development of siRNA-based treatments for diverse diseases. However, despite the promising therapeutic benefits of siRNAs, several problems, including impaired long-term protein expression, siRNA instability, off-target effects, immunological responses, and drug resistance, have been considerable obstacles to the use of siRNA-based antiviral therapies. This review provides an encompassing summary of the siRNA-based therapeutic approaches against viruses while also addressing the obstacles that need to be overcome for their effective application. Furthermore, we present potential solutions to mitigate major challenges.
