(Proper Name)
Oncolytic virotherapy (OV) is the most promising approach for tumor immunotherapy. OV uses replication-competent viruses that can proliferate selectively at tumor cells. Oncolytic viruses grouped as naturally occurring or genetically modified viruses. Natural occurring viruses like parvoviruses, and Newcastle disease viruses that selectively replicate in tumor cell without genetic modification. The second virus category, such as vesicular stomatitis viruses, adenoviruses, measles viruses, HSV and vaccinia viruses, genetically modified to improve the safety, tumor-specificity, and decrease virus pathogenicity. The therapeutic use of oncolytic viruses for cancer treatment is an immune-related treatment alternative. Oncolytic viruses act by directly lyses tumor cells and by introducing wild-type tumor suppressor genes into cells that lack the tumor suppressor gene. 48 , 49 Change in p53 gene function is present in half of all malignancies, and the induction of wild-type p53 gene re-establishes the normal p53 expression. Several recombinant OVs expressing p53 were developed with the aim of producing more potent OVs that act in combination with host immunity or with other treatments’ modality to destroy tumor cells. 49 , 50
Was the first approved gene product for the management of neck and head squamous cell carcinoma in 2003. 50 Gendicine is a non-replicative an adenoviral vector, where the E1 gene is replaced with the tumor suppressor p53 cDNA gene. The expression of p53 in tumor cells triggers the antitumor effect by activating the apoptotic pathway, inhibit damaged DNA repair, and anti-apoptotic activity. P53 gene mutation is prevalent in several cancers. Therefore, Gendicine induces the expression of p53 restores its activity and destroys the tumor cells. Generally, Gendicine management showed 30–40% complete response and 50–60% partial response with a total response rate of 90%–96% in different therapeutic use. Up-to-date greater than 30,000 patients managed by Gendicine. 50 , 51
It is the first replicative, oncolytic recombinant ad5 (rAd5-H101) approved to treat refractory nasopharyngeal cancer. Loss of p53 gene linked with drug resistance and survival rate reduction in non-small cell cancer patients. 50 Oncorine is an ad5 virus with a deletion in the E1B 55K gene. Host cell p53 gene inactivation is essential for wild-type to block the activation of apoptotic pathway. The removal of the E1B 55K gene inhibits viral proliferation in normal cells, allowing only proliferate in p53-deficient host cells. In tumor cells, viral proliferation causes oncolysis that is the mechanism to treat solid tumors. Following cancer cell lysis, adenoviruses release and infect another cell activating a serious of Oncorine-mediated cell death. 52 , 53
It is a genetically modified oncolytic HSV-1 approved in Europe in 2015 for the management of non-resectable metastatic melanoma. Imlygic is the first oncolytic virus used for the management of advanced melanoma. 48 The replacement of γ34.5 and α47 genes with the human granulocyte-macrophage colony-stimulating factor (GM-CSF) gene modifies the HSV-1 gene. The γ34.5 gene deletion causes tumor cell-selective replication and suppression of pathogenicity. The γ34.5 gene blocks protein synthesis of the host cell during viral infection. Thus, suppressing γ34.5 seizes the virus proliferation in normal cells. In tumor cells, the γ34.5 gene deleted HSV-1 can replicate. The α47gene inhibits the host cell transporter associated with antigen presentation. The depletion of α47gene reduces MHC class I expression that increases antitumor immune activity. 53 Besides, two human GM-CSF genes inserted into the virus providing high levels of GM-CSF production, and stimulate immune responses. Administration of Imlygic causes apoptosis of tumor cell enhanced antigen presentation and increased antitumor response. 49 , 54
Is the first targeted injectable vector approved for the management of metastatic cancers. It is a replication-incompetent retroviral vector showing a SIG -binding peptide to bind to abnormal Signature ( SIG ) proteins in the tumor cell that increase vector concentration in tumor cells and express a dominant-negative human cyclin G1 inhibitor. After the entrance into the tumor cells, Rexin-G synthesizes cytocidal dnG1 proteins that inhibit the cell cycle in the G1 phase resulting in apoptosis of cancer cells. 55 , 56
T cells destroy infected and tumor cells by detecting nonself antigens with the T cell receptor (TCR). CAR T is a T cell transduced with a chimeric antigen receptor specific to a tumor-associated antigen. CAR is “chimeric” because it contains the antigen-binding site of the B cell receptor and an intracellular TCR activation domain. CAR has three domains, an extracellular domain that has cancer-specific epitopes (scfv region) made from light (V L ) and heavy (V H ) chains of immunoglobin that target antigen (such as CD19), a transmembrane domain, and intracellular TCR derived stimulatory domains as showed in Figure 2 . The scfv component binds to the target antigen in the MHC independent way leading to CAR clustering and stimulating T-cell via intracellular region that posses the TCR-derived CD3ζ chain, with or without co-stimulatory domains. Stimulated CAR T-cells give target-specific memory cells that inhibit tumor relapse. 57 CD19‐targeted CAR T cells were the first CARs to be studied. CD19 is a promising target due to its expression limited to the B cell. First‐generation, CD19‐targeted CAR T cells were safe but ineffective. Second-generation CARs have a costimulatory domain with the CD3ζ activation domain show enhanced T cell activity. Two second‐generation, CD19‐targeted CARs are in clinical use contain a 41BB costimulatory domain (19‐BBz) and a CD28 costimulatory domain and those with more than one additional co-stimulatory molecule are known as “third-generation” CAR. 57–59
Schematic diagram of CAR-T-cell products.
It is the first FDA approved CAR T-cell-based gene product to treat relapsed B-cell acute lymphoblastic leukemia. Kymriah has autologous T cells, modified with the lent virus to encode a CAR consist of a murine single-chain antibody fragment (scFv) selective for CD19, an intracellular domain 4–1BB (CD137), and CD3 zeta with CD8 transmembrane hinge. After binding to CD19 antigen-expressing cells, Kymriah initiates the antitumor effect via the CD3 domain. The intracellular 4–1BB co-stimulatory domains enhance the antitumor activity. The CD19 antigen is a 95-kD glycoprotein encoded as a surface antigen in diffuse large B-cell lymphoma (DLBCL) and other B-cell lymphomas. 60 , 61 High response rates were recorded in patients with refractory DLBCL in Phase 2 clinical trials. The response rate was 50% at 3 months, 43% with a complete response at 6 months, and there were no patients with a complete response at 6 months who had a relapse by the median of 28.6 months. 62
It is another CAR T-cell therapy used for the management of aggressive non-Hodgkin lymphoma. It is CD19 antigen-specific ex-vivo modified autologous T cells infected with a gamma-retroviral. It encodes a CAR comprising an extracellular murine anti-CD19 single-chain variable fragment fused to a cytoplasmic domain that possesses CD28 and CD3-zeta co-stimulatory domains. 63 , 64
Allogeneic hematopoietic stem cell transplantation (allo-HSCT) uses for the management of several hematopoietic malignancies. But, acute graft-versus-host-disease (aGvHD) and Graft rejection are barriers to its success. The treatment strategy for haplo-HSCT depends on T-cell depletion or administration of lymphotoxin agents like cyclophosphamide after stem cell infusion to selectively deplete activated alloreactive lymphocytes but causes prolonged immunodeficiency post-transplantation. Thus, treatment to enhance immune reconstitution after transplantation is necessary. 65 Zalmoxis is a genetically modified allogeneic T cell using a retroviral vector encoding a human low-affinity nerve growth factor receptor (ΔLNGFR) and HSV-TK Mut2 to transduce the allogeneic T immune cells. The ΔLNGFR expression uses as a marker of the transduced T cells, and the HSV-TK Mut2 expression provides the suicide gene induction during the administration of the prodrug ganciclovir (GCV). Administration of the genetically modified donor T cells to T cell-depleted transplant patients (HSCT) reconstitutes the immunity to defend from infections. But, donor cells may specifically act as the host cells leading to Graft Versus Host Disease (GVHD). In this case, induction of suicide gene by GCV administration may kill the donor T cells encoding HSV-TK and control GVHD. Zalmoxis is a potential curative agent for HSCT patients when the matched donor does not exist. Zalmoxis provides post-transplant GvHD control, Graft versus Leukemia (GvL) improvement, relapse decrease, and immune reconstitution causes reduced infection. 52 , 66
Gene silencing therapy is RNA interference (RNAi)-mediated knockdown of specific genes in tumor cells. RNAi is single or double-stranded noncoding RNAs (21 ribonucleotides) that induce sequence-specific degradation of complementary mRNAs via the cells’ internal machinery. 67 siRNA is vital because most genes do not have inhibitors due to a lack of ligand binding sites and amino acid sequence homology with other proteins that limit target selectivity. RNAi consists of microRNA (miRNA), Small Interfering RNA (siRNA) and short hairpin RNA (shRNA). Two decades later after the discovery of RNAi, ONPATTRO™ (patisiran) approved for the first time for the management of the polyneuropathy of hereditary transthyretin‐mediated (hATTR) amyloidosis. 68 Tumor suppressor genes, oncogenes, genes involved in cancer progression, and drug-resistance are promising targets for gene silencing by RNAi-based cancer treatment due to selective gene silencing effect and relatively fewer adverse effects than conventional chemotherapy. 69 The merits of RNAi in cancer treatment are targeting several genes of different cellular pathways involved in cancer progression and develop a drug for a specific patient. 70 Several studies conducted on animals revealed that targeting vital proteins in the cell cycle, such as Protein kinase N3 (PKN3), kinesin spindle protein (KSP), and polo-like kinase 1 (PLK1) by siRNA displayed a potent antitumor effect. Several liposomal siRNA dose preparations are in Phase 1 trials, such as treatments for pancreatic cancer (PKN3 siRNA), liver cancer (CEBPA siRNA), and neuroendocrine tumors (PLK1 siRNA). 71
Suicide gene therapy uses viral or bacterial genes into malignant cells that metabolize non-toxic prodrug into a toxic compound. Several suicide gene systems were identified including the HSV-thymidine kinase gene (HSV-TK) with ganciclovir (GCV) and the cytosine deaminase gene (CD) with 5-fluorocytosine (5-FC). 72 Gene-mediated cytotoxic immunotherapy is one strategy where an adenoviral vector possessing the herpes virus thymidine kinase gene (AdV-TK) is administered locally into the tumor site that causes local expression of the HSV-TK gene to the synthesis of viral thymidine kinase that converts GCV to GCV monophosphate. The next step is the administration of GCV that is a substrate of HSV-TK and phosphorylated to produce GCV monophosphate. Then, cellular kinases metabolize GVC-monophosphate into GVC-triphosphate. GCV triphosphate is a deoxyguanosine triphosphate analog, incorporated into the DNA chain causing chain termination and tumor cell death. 73
The anti-tumor effect of the TK/GCV system showed promising results in animal models. A study on hormone-refractory prostate cancer patients treated with HSV-TK delivered by adenovirus followed by GCV. The result showed response was at the surrogate marker level and safe. Several studies are in Phase III trials. 74 The cytosine deaminase (CD) enzyme exists in fungi and bacteria but not in mammalian cells, metabolizes cytosine into uracil. CD metabolizes the non-toxic prodrug 5-FC into 5-FU, which is subsequently metabolized by cellular enzymes into 5-FdUMP, 5-FdUTP, and 5-FUTP. Inhibition of thymidylate synthase and production of (5-FU) DNA and RNA are the mode of cell death induced by the CD/5-FC suicide system. 5-FU uses for cancer treatment but requires a high dose. This suicide system results in tumor-targeted chemotherapy with few side effects. The CD/5-FC system improved by the inclusion uracil phosphoribosyltransferase (UPRT) gene that phosphorylates 5-FU to 5-fluorouridine mono-phosphate, the first step of its pathway to activation. 75 The anti-tumor effect of the CD/5-FC combination showed a better efficacy in animal models. A study on refractory cancer patients that involved intratumoral administration of TAPET-CD attenuated Salmonella bacterium encoding the E. coli CD gene in three patients. The study showed a significant effect and lack of side effects. An oncolytic adenovirus possessing a CD/HSV-1 TK gene was used in a phase I study in patients with prostate cancer. The result showed that the transgene encoding persistence in the prostate for 3 weeks after administration. 76
Tumor-driven angiogenesis several growth factors are involved, such as vascular endothelial growth factor (VEGF), fibroblast growth factor-2 (FGF-2), angiopoietins or IL-8, to secure oxygen and nutrients supply. Two major approaches are being pursued to block tumor angiogenesis. The first approach is down-regulation of pro-angiogenic factors expression, such as VEGF, and the second approach is up-regulation of expression of anti-angiogenic factors such as angiostatin, endostatin, and human soluble FMS-like tyrosine kinase receptor. Despite the successful therapeutic use of mAb like Bevacizumab for targeted therapy of cancer, the production and administration of therapeutic mAb are limited due to costly production. Therefore, gene-based studies were done to develop an angiogenesis-targeted cancer treatment. 77 , 78
Gene therapy represents a novel alternative for the management of diseases that have no satisfactory cure. Gene therapy for cancer treatment has good progress in the last three decades, few drugs approved, while others are still in trials. Relatively gene therapy has better safety with tolerable adverse effects than chemotherapy for the treatment of cancer. In the future, tumor genomic analysis, assessment of host humoral and cellular immunity will facilitate a better selection of the most appropriate patient for gene therapy. Recent progress in developing safe and effective vectors for gene delivery, and understanding the activity of nucleases facilitate future genome editing as new treatment approaches for untreatable diseases like cancer.
The success of using autologous and allogenic chimeric antigen receptor integrated T-lymphocytes in mediating adoptive immunotherapy enhances the safety and effectiveness of gene therapy. Besides, the enhanced biological research, cheaper gene vectors will be available in the market, which increases gene therapy accessibility for most cancer patients. This will change the future of cancer treatment, from generalized cancer treatment strategies to individualized cancer treatment, based on the patient’s specific genome, immune status, and genetic profile of the tumor. Gene therapy is expected to be fast, effective, less toxic, and inexpensive, with higher cure rates. In November 2017, more than 2597 clinical trials are ongoing in several countries and a few of them are listed in Table 2 . Until August 2019, 22 gene medicines had been approved by the drug regulatory agencies from various countries. 79 Gene therapy gradually accepted by the government and the public since the 1980s and has become an important alternative to the existing treatments in the past few years. Therefore, gene therapy drugs, with safe vectors and advanced biotechnologies, would play a greater role in the prophylaxis and management of cancer in the future.
Gene Therapies Products Candidates Under Clinical Trial
Drug Name | Manufacturer | Indication | Phase | Vector (Delivery Mode) |
---|---|---|---|---|
NSR-REP1 | Nightstar Therapeutics | Choroideremia | 2 | AAV (in vivo) |
DNX-2401 | DNAtrix | Glioblastoma/gliosarcoma | 2 | Adenovirus (in vivo) |
ONCOS-102 | Targovax | Mesothelioma | 1/2 | Adenovirus (in vivo) |
Ofranergene obadenovec (VB-111) | VBL Therapeutics | Glioblastoma | 3 | Adenovirus (in vivo) |
Sepravir | Virtuu | Mesothelioma | 1/2 | Herpesvirus (in vivo) |
Pexastimogene devacirepvec (Pexa-Vec) | SillaJen | Hepatocellular carcinoma | 3 | Vaccinia (in vivo) |
Vocimagene amiretrorepvec (Toca 511) | Tocagen | Glioma | 3 | Retrovirus (ex vivo) |
I would like to acknowledge Mrs Fasika Abu for editing the manuscript for English Style.
ADA, adenosine deaminase; Ad, adenovirus; AAV, adeno-associated virus; aGvHD, acute graft-versus-host-disease; allo-HSCT, allogeneic hematopoietic stem cell transplantation; CRISPR, Clustered Regularly Interspaced Short Palindromic Repeats; CAR, chimeric antigen receptor; DSBs, double-strand breaks; ERT, enzyme replacement therapy; HDR, homology-directed repair; HSV, herpes simplex virus; IRDs, inherited retinal degenerations; LV, lentivirus; NHEJ, non-homologous end joining; NMDs, neuromuscular disorders; OV, oncolytic virotherapy; tracrRNA, trans-activating RNA; TCR, T cell receptor; MNs, meganucleases.
All data are provided in the manuscript or found from published papers as cited.
The authors declare no competing interests in this work.
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There is also the important issue of the target cell type of gene therapy that currently is subdivided into two large groups: gene therapy of the germline and gene therapy of somatic cells. ( 8 ) In germline gene therapy, the stem cells, e.g. , with the sperm and egg, are modified by the introduction of functional genes, which are integrated ...
human gene therapy 16) 1) The disease is an incurable, life-threatening disease; 2) Or gan, tissue and cell types affected by the disease have been. identified. 3) The normal counterpart of the ...
Introduction. The idea that a gene can be delivered into specific cell types and its expression can lead to therapeutic efficacy, dramatically improving the patients' quality of life, was originally introduced by Theodore Friedmann 45 years ago and was later strongly encouraged and realized by George Stamatoyannopoulos, one of the founding members of the American Society of Gene and Cell ...
The introduction of gene therapy into the clinic provided hope for thousands of patients with genetic diseases and limited treatment options. ... The remaining 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.
Introduction Gene therapy is an emerging topic in medicine. The first products have already been licensed in the European Union for the treatment of immune deficiency, spinal muscular atrophy, hemophilia, retinal dystrophy, a rare neurotransmitter disorder and some hematological cancers, while many more are being assessed in preclinical and clinical trials. Objective The purpose of this review ...
century ago, gene therapy research has advanced dramatically. Recently the pace of progress has intensified. In the past five years the U.S. Food and Drug Administration has approved more than half a dozen gene therapy products aimed at several types of cancer and inherited conditions. These treatments work in various ways, such as delivering
RSS Feed. Gene therapy involves the introduction of new genes into cells, to restore or add gene expression, for the purpose of treating disease. Most commonly a mutated gene is replaced with DNA ...
Gene Therapy 2.0. In the past decade technological advances have ushered in a new era, and the definition of gene therapy continues to evolve, Mali says. ... Since the concept of treating diseases ...
After reviewing 1908 gene therapy clinical trials from 2010 to October 2020, it was concluded that they could be classified into three major fields: cancers, monogenic and polygenic disorders (genetic disorders), infections, and other studies. 5.1. Gene therapy, an emerging treatment for cancers.
In 1972, Theodore Friedmann and Richard Roblin proposed gene therapy in their paper published in Science, opening with "gene therapy may ameliorate some human genetic diseases in the future". Since then, almost half a century has passed and the field has been making slow but steady progress in turning their imagined future into reality. Gene therapy was first included in clinical trials in ...
Onasemnogene abeparvovec is an adeno-associated virus (AAV) vector-based gene therapy that delivers a functional copy of the SMN1 gene encoding SMN protein to motor neuron cells. 2. This restores SMN levels and reverses skeletal muscle atrophy, with clinical benefits demonstrated for up to 7.5 years thus far. 3.
458 n engl j med 381;5 nejm.orgAugust 1, 2019 The new england journal of medicine More than 20 years ago, the first ex vivo gene-therapy studies of γ-retroviral vectors in children with ADA ...
Introduction to Theoretical Concepts and Early Background History Impacting HSC Gene Therapy. The history of gene therapy comprises the advance of theoretical concepts, understanding the human genome, availability of critical materials and instruments, design of vectors and chemical tools to manipulate and change genomic DNA, improvements in the procurement and culture/maintenance of stemness ...
Gene therapy has been adapted for treatment of malignant diseases to improve the outcome of … A Brief Introduction to Current Cancer Gene Therapy Methods Mol Biol. 2022:2521:1-21. doi: 10.1007 ... 2 Experimental and Clinical Research Center, Charité - Universitätsmedizin Berlin, Berlin, ...
Abstract. The present article is an overview of gene therapy with an emphasis on different approaches and its implications in the clinic. Genetic interventions have been applied to the diagnosis of and therapy for an array of human diseases. The initial concept of gene therapy was focused on the treatment of genetic diseases.
mimicked by gene addition therapy as discussed earlier (figure 1). Thus, with the advance of gene editing to the clinical routine through the first market approval of a gene editing-based therapy on Nov 16, 2023, 7 . gene therapy has entered a new age. Genome editing tools and modes of action. The process of genome editing is initiated by ...
Introduction. Human gene therapy is defined as the treatment of disorder or disease through transfer of engineered genetic material into human cells, often by viral transduction. Since the introduction of science fiction, the popular press has toyed with the notion of viral gene delivery and its terrifying implications.
Gene Therapy: A New Ap proach in Modern Medicine. Azam Y azdani, Zahra Alirezaie, Mohammad Javad Motamedi, Jafar Amani3*. 1 Department of Biology, Faculty of Basic Science, Shahed University ...
Introduction. Over the last decade ... 33 papers were selected. ... Studies involving the public generally reported support for cell and gene therapy research 16,17,18,24,29,30,34,38,42,45,46 with ...
• Introduction • Principles of ... M., et al. "Review article on gene therapy." Research Journal of . Pharmacology and Pharm acodynamics 4.2 (20 12): 77-83. ... Gene therapy, considered as ...
The introduction of Jude Samulski's PhD thesis contained a bold goal: develop a gene therapy vector that could be used to treat the world's genetic diseases. By 1982, he had first cloned the ...
Introduction. Over the last decade, new cell, gene and tissue-engineered therapies have been developed to treat various cancers, inherited diseases and some chronic conditions 1.They offer opportunities for the treatment of disease and injury, to restore function, and in some cases offer cures 1 - 4.. These therapies are approved and regulated in the US by the Center for Biologics Evaluation ...
Gene therapy is a new treatment method. Gene transfer has always been the bottleneck of gene therapy success. The first clinical trial of gene therapy was approved in 1989. Nearly 2,600 trials have been completed or are underway worldwide . However, it is still a challenge to introduce genes into target cells without damaging other cells.
Gene therapy is a promising treatment for several inherited. or acquired hematologic disorders. Gene therapy involves. the introduc tion of a functional gene to replace a mutated. gene or a ...
The promise of gene therapy looms large for families dealing with rare, genetic disorders. Such treatments offer the possibility of one-time cures. ... Research hasn't made it past early stages for many of them. Lacey Henderson's daughter, 5-year-old Estella, has alternating hemiplegia of childhood, a neurological condition that affects 300 ...
Oncorine (rAd5-H101) It is the first replicative, oncolytic recombinant ad5 (rAd5-H101) approved to treat refractory nasopharyngeal cancer. Loss of p53 gene linked with drug resistance and survival rate reduction in non-small cell cancer patients. 50 Oncorine is an ad5 virus with a deletion in the E1B 55K gene.