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Sanchala DS, Bhatt LK, Prabhavalkar KS. Oncolytic Herpes Simplex Viral Therapy: A Stride toward Selective Targeting of Cancer Cells. Front Pharmacol 2017; 8:270. [PMID: 28559846 PMCID: PMC5432606 DOI: 10.3389/fphar.2017.00270] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 05/01/2017] [Indexed: 12/18/2022] Open
Abstract
Oncolytic viral therapy, which makes use of replication-competent lytic viruses, has emerged as a promising modality to treat malignancies. It has shown meaningful outcomes in both solid tumor and hematologic malignancies. Advancements during the last decade, mainly genetic engineering of oncolytic viruses have resulted in improved specificity and efficacy of oncolytic viruses in cancer therapeutics. Oncolytic viral therapy for treating cancer with herpes simplex virus-1 has been of particular interest owing to its range of benefits like: (a) large genome and power to infiltrate in the tumor, (b) easy access to manipulation with the flexibility to insert multiple transgenes, (c) infecting majority of the malignant cell types with quick replication in the infected cells and (d) as Anti-HSV agent to terminate HSV replication. This review provides an exhaustive list of oncolytic herpes simplex virus-1 along with their genetic alterations. It also encompasses the major developments in oncolytic herpes simplex-1 viral therapy and outlines the limitations and drawbacks of oncolytic herpes simplex viral therapy.
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Affiliation(s)
| | - Lokesh K. Bhatt
- Department of Pharmacology, Dr. Bhanuben Nanavati College of Pharmacy, Vile Parle (W)Mumbai, India
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2
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Glorioso JC. Herpes simplex viral vectors: late bloomers with big potential. Hum Gene Ther 2014; 25:83-91. [PMID: 24502405 DOI: 10.1089/hum.2014.2501] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- Joseph C Glorioso
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine , Pittsburgh, PA 15219
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Mandel RJ, Burger C, Snyder RO. Viral vectors for in vivo gene transfer in Parkinson's disease: properties and clinical grade production. Exp Neurol 2008; 209:58-71. [PMID: 17916354 PMCID: PMC2695880 DOI: 10.1016/j.expneurol.2007.08.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2007] [Revised: 08/08/2007] [Accepted: 08/16/2007] [Indexed: 12/18/2022]
Abstract
Because Parkinson's disease is a progressive degenerative disorder that is mainly confined to the basal ganglia, gene transfer to deliver therapeutic molecules is an attractive treatment avenue. The present review focuses on direct in vivo gene transfer vectors that have been developed to a degree that they have been successfully used in animal model of Parkinson's disease. Accordingly, the properties of recombinant adenovirus, recombinant adeno-associated virus, herpes simplex virus, and lentivirus are described and contrasted. In order for viral vectors to be developed into clinical grade reagents, they must be manufactured and tested to precise regulatory standards. Indeed, clinical lots of viral vectors can be produced in compliance with current Good Manufacturing Practices (cGMPs) regulations using industry accepted manufacturing methodologies, manufacturing controls, and quality systems. The viral vector properties themselves combined with physiological product formulations facilitate long-term storage and direct in vivo administration.
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Affiliation(s)
- Ronald J. Mandel
- Department of Neuroscience, PO box 100244, Gainesville, FL 32610, Tel. 352–294–0446, Fax: 352–392–8347,
- McKnight Brain Institute
- Powell Gene Therapy Center
- University of Florida, College of Medicine
| | - Corinna Burger
- Department of Neurology, University of Wisconsin Medical School
| | - Richard O. Snyder
- Powell Gene Therapy Center
- Department of Molecular Genetics and Microbiology, PO Box 100266, 1600 SW Archer Road, Gainesville, FL 32610–0266, Tel: 386–418–1642, Fax: 352–392–4290, e-mail:
- Department of Pediatrics
- University of Florida, College of Medicine
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4
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Abstract
Cancer remains a serious threat to human health, causing over 500 000 deaths each year in US alone, exceeded only by heart diseases. Many new technologies are being developed to fight cancer, among which are gene therapies and oncolytic virotherapies. Herpes simplex virus type 1 (HSV-1) is a neurotropic DNA virus with many favorable properties both as a delivery vector for cancer therapeutic genes and as a backbone for oncolytic viruses. Herpes simplex virus type 1 is highly infectious, so HSV-1 vectors are efficient vehicles for the delivery of exogenous genetic materials to cells. The inherent cytotoxicity of this virus, if harnessed and made to be selective by genetic manipulations, makes this virus a good candidate for developing viral oncolytic approach. Furthermore, its large genome size, ability to infect cells with a high degree of efficiency, and the presence of an inherent replication controlling mechanism, the thymidine kinase gene, add to its potential capabilities. This review briefly summarizes the biology of HSV-1, examines various strategies that have been used to genetically modify the virus, and discusses preclinical as well as clinical results of the HSV-1-derived vectors in cancer treatment.
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Affiliation(s)
- Y Shen
- Mary Crowley Medical Research Center, Dallas, TX 75201, USA
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5
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Oehmig A, Fraefel C, Breakefield XO. Update on herpesvirus amplicon vectors. Mol Ther 2005; 10:630-43. [PMID: 15451447 DOI: 10.1016/j.ymthe.2004.06.641] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2004] [Accepted: 06/17/2004] [Indexed: 12/29/2022] Open
Affiliation(s)
- Angelika Oehmig
- Department of Neurology, Massachusetts General Hospital, and Program in Neuroscience, Harvard Medical School, Boston, MA 02114, USA
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Calderwood MA, White RE, Whitehouse A. Development of herpesvirus-based episomally maintained gene delivery vectors. Expert Opin Biol Ther 2005; 4:493-505. [PMID: 15102599 DOI: 10.1517/14712598.4.4.493] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Successful gene therapy aims to deliver and express therapeutic genes to cure or slow the progression of disease. However, a major obstacle in the application of gene therapy has been the development of the vectors used to deliver heterologous DNA to the cell or tissue of choice. A number of viral- and non-viral-based vector systems have undergone clinical trials with varying success. However, at present, no vector system possesses the full complement of properties that are generally believed necessary in an ideal gene delivery system. Therefore, alongside attempts to improve current gene delivery vectors, the identification and evaluation of new viral vectors is crucial for the long-term success of gene therapy. Herpesviruses are large DNA viruses which possess a number of advantages as gene delivery vectors. These relate to an ability to package large DNA insertions and establish lifelong latent infections in which the genomic material exists as a stable episome. This review aims to highlight the potential of herpesvirus vectors, in particular an alternative vector system based on herpesvirus saimiri (HVS). HVS is capable of infecting a range of human cell lines with high efficiencies, and the viral genome persists as high copy number, circular, non-integrated episomes which segregate to progeny following cell division. This allows the virus-based vector to stably transduce a dividing cell population and provide sustained transgene expression for an extended period of time both in vitro and in vivo. Moreover, the insertion of a bacterial artificial chromosome cassette into the HVS genome simplifies the incorporation of large amounts of heterologous DNA for gene delivery. These properties offer characteristics similar to an artificial chromosome combined with an efficient delivery system and merit its continual development as a possible gene delivery vector for the future.
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Kalamvoki M, Mavromara P. Calcium-dependent calpain proteases are implicated in processing of the hepatitis C virus NS5A protein. J Virol 2004; 78:11865-78. [PMID: 15479828 PMCID: PMC523276 DOI: 10.1128/jvi.78.21.11865-11878.2004] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The nonstructural 5A (NS5A) protein of the hepatitis C virus (HCV) is a multifunctional phosphoprotein that is implicated in viral replication and HCV-mediated pathogenesis. We report here that the NS5A protein from the HCV genotype 1a is processed into shorter distinct forms when expressed in mammalian cells (Vero, HepG2, HuH-7, and WRL68) infected with an NS5A-expressing HSV-1-based amplicon vector or when transiently transfected with NS5A-expressing plasmids in the absence of exogenous apoptotic stimuli. Inhibitor studies combined with cell-free cleavage assays suggest that calcium-dependent calpain proteases, in addition to caspase-like proteases, are involved in NS5A processing. Interestingly, His-tagging experiments indicated that all the detectable NS5A-cleaved products are N-terminal forms of the protein. Additionally, immunofluorescence studies showed that, despite proteolytic cleavage, the NS5A protein exhibits a cytoplasm-perinuclear localization similar to that of the full-length protein. Thus, our results are consistent with recent data that demonstrated that NS5A is capable of perturbing intracellular calcium homeostasis and suggest that NS5A is both an inducer and a substrate of the calcium-dependent calpain protease(s). This may imply that cleavage of NS5A by calpain(s) could play a role in the modulation of NS5A function.
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Affiliation(s)
- M Kalamvoki
- Hellenic Pasteur Institute, Laboratory of Molecular Virology, 127 Vas. Sofias Ave., Athens, Greece 115 21
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Argnani R, Boccafogli L, Marconi PC, Manservigi R. Specific targeted binding of herpes simplex virus type 1 to hepatocytes via the human hepatitis B virus preS1 peptide. Gene Ther 2004; 11:1087-98. [PMID: 15057264 DOI: 10.1038/sj.gt.3302266] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
To improve the utility of herpes simplex virus type 1 (HSV-1) vectors for gene therapy, the viral envelope needs to be manipulated to achieve cell-specific gene delivery. In this report, we have engineered an HSV-1 mutant virus, KgBpK(-) gC(-), deleted for the glycoprotein C (gC) and the heparan sulfate-binding domain (pK) of gB, in order to express gC:preS1 and gC:preS1 active peptide (preS1ap) fusion molecules. PreS1, and a 27 amino acid active peptide inside preS1 (preS1ap), are supposed to be the molecules that the human hepatitis B virus (HBV) needs to bind specifically to hepatocytes. Biochemical analysis demonstrated that the gC:preS1ap fusion molecule was expressed and incorporated into the envelope of the recombinant HSV-1 virus KgBpK(-)gC:preS1ap. Moreover, KgBpK(-)gC:preS1ap recombinant virus gained a specific binding activity to an hepatoblastoma cell line (HepG2) with a consequent productive infection. In addition, anti-preS1-specific antibodies were shown to neutralize recombinant virus infectivity, and a synthetic preS1ap peptide was able to elute KgBpK(-)gC:preS1ap virus bound on HpeG2 cells. These data provide further evidence that HSV-1 can productively infect cells through a specific binding to a non-HSV-1 receptor. Furthermore, these data strongly support the hypothesis that the HBV preS1ap molecule is an HBV ligand to hepatocytes.
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Affiliation(s)
- Rafaela Argnani
- Department of Experimental and Diagnostic Medicine, Section of Microbiology, University of Ferrara, Ferrara, Italy
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Jounaidi Y, Waxman DJ. Use of replication-conditional adenovirus as a helper system to enhance delivery of P450 prodrug-activation genes for cancer therapy. Cancer Res 2004; 64:292-303. [PMID: 14729637 DOI: 10.1158/0008-5472.can-03-1798] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cytochrome P450 (CYP) gene transfer sensitizes tumor xenografts to anticancer prodrugs such as cyclophosphamide (CPA) without a detectable increase in host toxicity. Optimal prodrug activation is achieved when a suitable P450 gene (e.g., human CYP2B6) is delivered in combination with NADPH-cytochrome P450 reductase (P450R), which encodes the flavoenzyme P450 reductase. We sought to improve this gene therapy by coordinated delivery and expression of P450 and P450R on a single bicistronic vector using an internal ribosomal entry site (IRES) sequence. Retrovirus encoding a CYP2B6-IRES-P450R expression cassette was shown to induce strong P450-dependent CPA cytotoxicity in a population of infected 9L gliosarcoma cells. Adeno-P450, a replication-defective, E1/E3 region-deleted adenovirus engineered to express CYP2B6-IRES-P450R, induced intracellular CPA 4-hydroxylation, and CPA cytotoxicity, in a broad range of human cancer cell lines. However, limited Adeno-P450 gene transfer and CPA chemosensitization was seen with certain human tumor cells, notably PC-3 prostate and HT-29 colon cancer cells. Remarkable improvements could be obtained by coinfecting the tumor cells with Adeno-P450 in combination with Onyx-017, an E1b-55k gene-deleted adenovirus that selectively replicates in p53 pathway-deficient cells. Substantial increases in gene expression were observed during the early stages of viral infection, reflecting an apparent coamplification of the Adeno-P450 genome, followed by enhanced viral spread at later stages, as demonstrated in cultured tumor cells, and in A549 and PC-3 solid tumor xenografts grown in scid mice. This combination of the replication-defective Adeno-P450 with a replication-conditional and tumor cell-targeted helper adenovirus dramatically improved the low gene transfer observed with some human tumor cell lines and correspondingly increased tumor cell-catalyzed CPA 4-hydroxylation, CPA cytotoxicity, and in vivo antitumor activity in a PC-3 tumor xenograft model. The use of tumor-selective, replicating adenovirus to promote the spread of replication-defective gene therapy vectors, such as Adeno-P450, substantially increases the therapeutic potential of adenoviral delivery systems, and should lead to increased activity and enhanced tumor selectivity of cytochrome P450 and other gene-directed enzyme prodrug therapies.
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Affiliation(s)
- Youssef Jounaidi
- Division of Cell and Molecular Biology, Department of Biology, Boston University, Boston, Massachusetts 02215, USA
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Shah K, Tang Y, Breakefield X, Weissleder R. Real-time imaging of TRAIL-induced apoptosis of glioma tumors in vivo. Oncogene 2003; 22:6865-72. [PMID: 14534533 DOI: 10.1038/sj.onc.1206748] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) has been shown to induce apoptosis in neoplastic cells. While many previous studies have been performed in cell culture, the delivery and efficiency of TRAIL variants in vivo is less well established. Using dual substrate/reporter bioluminescence imaging (Fluc: firefly luciferase-luciferin and Rluc: Renilla luciferase-coelenterazine), we tested the efficacy of TRAIL using replication-deficient herpes simplex virus (HSV) type 1 amplicon vectors in gliomas. The cDNA for complete TRAIL and the extracellular domain of TRAIL (aa 114-281) were cloned into HSV amplicons and packaged into helper virus-free vectors. Both forms of TRAIL induced similar degrees of apoptosis in human glioma cells (Gli36) in culture within 24 h of infection with TRAIL amplicon vectors. Growth of tumors stably transfected with Fluc (Gli36fluc+) was readily monitored in vivo by bioluminescence imaging following luciferin administration. HSV amplicon vectors bearing the genes for TRAIL and Rluc injected directly into Gli36fluc(+)-expressing subcutaneous gliomas revealed peak Rluc activity 36 h after intratumoral injection as determined by coelenterazine injection followed by imaging. TRAIL-treated gliomas regressed in size over a period of 4 weeks as compared to the mock-injected gliomas. These results show the efficacy of vector delivered TRAIL in treating tumors in vivo and offer a unique way to monitor both gene delivery and efficacy of TRAIL-induced apoptosis in tumors in vivo in real time by dual enzyme substrate (Rluc/Fluc) imaging.
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Affiliation(s)
- Khalid Shah
- Center for Molecular Imaging Research, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
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11
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Kubo S, Saeki Y, Chiocca EA, Mitani K. An HSV amplicon-based helper system for helper-dependent adenoviral vectors. Biochem Biophys Res Commun 2003; 307:826-30. [PMID: 12878185 DOI: 10.1016/s0006-291x(03)01256-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
To produce a helper virus-free stock of helper-dependent adenoviral vectors (HDAdVs), we have developed a new helper system in which adenoviral genes for propagation of HDAdVs are delivered into producer cells by a herpes simplex virus-1 (HSV) amplicon-adenovirus hybrid. The hybrid amplicon was constructed to carry the E1 gene (HA-E1) or the entire adenoviral genome except E1 (HA-Ad). E1 expression from the HSV amplicon successfully complemented propagation of an E1-deleted adenoviral vector in a human glioma cell line. HDAdVs were propagated in 293 cells infected with HA-Ad. In addition, HDAdVs were rescued and propagated in a glioma cell line superinfected with both HA-E1 and HA-Ad amplicons, although relatively low titers of HSV amplicon resulted in low propagation efficiency of HDAdVs. Since the HSV amplicon can be easily and completely inactivated by chloroform extraction and/or heat treatment from the HDAdV stock, this helper system might be an alternative method to produce helper virus-free HDAdVs.
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Affiliation(s)
- Shuji Kubo
- Department of Microbiology, Immunology and Molecular Genetics, UCLA School of Medicine, Los Angeles, CA, USA
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12
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Yang CT, Song J, Bu X, Cong YS, Bacchetti S, Rennie P, Jia WWG. Herpes simplex virus type-1 infection upregulates cellular promoters and telomerase activity in both tumor and nontumor human cells. Gene Ther 2003; 10:1494-502. [PMID: 12900765 DOI: 10.1038/sj.gt.3302005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Targeted gene expression through viral vectors has been a promising approach for gene therapy. However, the effects of viral gene products expressed from virus vectors on the expression of the host gene are not well known. In the present study, we examined the activities of cellular promoters, including the promoter for genes of human telomerase reverse transcriptase (hTERT), tyrosinase and probasin, in both tumor and normal cells after infection with herpes simplex virus type 1 (HSV-1) vectors. Our results showed that infection with replication-defective HSV-1 vectors significantly upregulated the activity of all three cellular promoters in a nonsequence specific fashion in all cell types tested. Furthermore, viral infection upregulated activities of the hTERT promoter and endogenous telomerase in nontumoral cells. Additional experiments suggested that the viral immediate-early gene product, infected cell protein 0, might be responsible for the deregulation of cellular promoter activity and activation of telomerase. Our study alerts to the potential risk of oncogenesis through deregulation of host gene expression, such as the telomerase by viral vectors in normal cells.
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Affiliation(s)
- C-T Yang
- Department of Internal Medicine, Chang Gung Memorial Hospital, Chiayi, Taiwan
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13
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Borst EM, Messerle M. Construction of a cytomegalovirus-based amplicon: a vector with a unique transfer capacity. Hum Gene Ther 2003; 14:959-70. [PMID: 12869214 DOI: 10.1089/104303403766682223] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Cytomegalovirus (CMV) has a number of interesting properties that qualifies it as a vector for gene transfer. Especially appealing is the ability of the CMV genome to persist in hematopoietic progenitor cells and the packaging capacity of the viral capsid that accommodates a DNA genome of 230 kbp. In order to exploit the packaging capacity of the CMV capsid we investigated whether the principles of an amplicon vector can be applied to CMV. Amplicons are herpesviral vectors, which contain only the cis-active sequences required for replication and packaging of the vector genome. For construction of a CMV amplicon the sequences comprising the lytic origin of replication (orilyt) and the cleavage packaging recognition sites (pac) of human CMV were cloned onto a plasmid. A gene encoding the green fluorescent protein was used as a model transgene. The amplicon plasmid replicated in the presence of a CMV helper virus and was packaged into CMV particles, with replication and packaging being dependent on the presence of the orilyt and pac sequences. The packaged amplicon could be transferred to recipient cells and reisolated from the transduced cells. Analysis of the DNA isolated from CMV capsids revealed that the CMV amplicon was packaged as a concatemer with a size of approximately 210 kbp. The CMV amplicon vector has the potential to transfer therapeutic genes with a size of more than 200 kbp and thus provides a unique transfer capacity among viral vectors.
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Affiliation(s)
- Eva Maria Borst
- Virus Cell Interaction Group, Medical Faculty, University of Halle-Wittenberg, 06120 Halle (Saale), Germany
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14
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Prieto J, Solera J, Tabarés E. Development of new expression vector based on Pseudorabies virus amplicons: application to human insulin expression. Virus Res 2002; 89:123-9. [PMID: 12367755 DOI: 10.1016/s0168-1702(02)00128-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Pseudorabies virus (PrV), a herpesvirus from the Alphaherpesvirinae subfamily, is suitable for amplicon vector replication and packaging into virions, with helper virus for trans replication and cleavage-packaging functions. PrV amplicon vectors were developed in a bacterial plasmid construction using PrV ori(s) and pac signals as the required cis elements. Human insulin cDNA was then cloned in the amplicon vector for human proinsulin expression. In the same construction, green fluorescent protein was used as a marker. PrV amplicons may have several advantages over herpes simplex virus type 1 (HSV1) amplicons in human gene therapy because it can infect human cells in vitro and in vivo, it is not pathogenic for primates and there is no pre-existing immunity and risk of recombination with latent PrV as occurs with HSV1.
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Affiliation(s)
- Jesús Prieto
- Departamento de Medicina Preventiva y Salud Pública, Facultad de Medicina, Universidad Autónoma de Madrid, Arzobispo Morcillo 4, 28029 Madrid, Spain
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15
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Advani SJ, Weichselbaum RR, Whitley RJ, Roizman B. Friendly fire: redirecting herpes simplex virus-1 for therapeutic applications. Clin Microbiol Infect 2002; 8:551-63. [PMID: 12427216 DOI: 10.1046/j.1469-0691.2002.00432.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Herpes simplex virus-1 (HSV-1) is a relatively large double-stranded DNA virus encoding at least 89 proteins with well characterized disease pathology. An understanding of the functions of viral proteins together with the ability to genetically engineer specific viral mutants has led to the development of attenuated HSV-1 for gene therapy. This review highlights the progress in creating attenuated genetically engineered HSV-1 mutants that are either replication competent (viral non-essential gene deleted) or replication defective (viral essential gene deleted). The choice between a replication-competent or -defective virus is based on the end-goal of the therapeutic intervention. Replication-competent HSV-1 mutants have primarily been employed as antitumor oncolytic viruses, with the lytic nature of the virus harnessed to destroy tumor cells selectively. In replacement gene therapy, replication-defective viruses have been utilized as delivery vectors. The advantages of HSV-1 vectors are that they infect quiescent and dividing cells efficiently and can encode for relatively large transgenes.
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Affiliation(s)
- S J Advani
- The Marjorie B. Kovler Viral Oncology Laboratories, The University of Chicago, Chicago, Illinois 60637, USA.
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Abstract
Parkinson's disease is one of the most likely neurological disorders to be fully treatable by drugs and new therapeutic modalities. The age-dependent and multifactorial nature of its pathogenesis allows for many strategies of intervention and repair. Most data indicate that the selectively vulnerable dopaminergic neurons in the substantia nigra of patients that have developed Parkinson's disease can be modified by protective and reparative therapies. First, the oxidative stress, protein abnormalities, and cellular inclusions typically seen could be dealt with by anti-oxidants, trophic factors, and proteolytic enhancements. Secondly, if the delay of degeneration is not sufficient, then immature dopamine neurons can be placed in the parkinsonian brain by transplantation. Such neurons can be derived from stem cell sources or even stimulated to repair from endogenous stem cells. Novel molecular and cellular treatments provide new tools to prevent and alleviate Parkinson's disease.
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Affiliation(s)
- Ole Isacson
- Neuroregeneration Laboratories, McLean Hospital/Harvard Medical School, Belmont, MA 02478, USA.
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17
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Smith PG, Coletta PL, Markham AF, Whitehouse A. In vivo episomal maintenance of a herpesvirus saimiri-based gene delivery vector. Gene Ther 2001; 8:1762-9. [PMID: 11803395 DOI: 10.1038/sj.gt.3301595] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2001] [Accepted: 10/09/2001] [Indexed: 11/09/2022]
Abstract
Herpesvirus saimiri (HVS) has several properties that make it amenable to development as a gene delivery vector. HVS offers the potential to incorporate large amounts of heterologous DNA and infect a broad range of human cell lines. Upon infection the viral genome can persist by virtue of episomal maintenance and stably maintains heterologous gene expression. Here we report an evaluation of the in vivo properties of HVS, with a view to its development as a gene delivery system. We demonstrate for the first time, the long-term persistence of the HVS genome in tumour xenografts generated from HVS-infected human carcinoma cell lines. The HVS-based vector remained latent in the xenograft without spreading to other organs. Moreover, the long-term in vivo maintenance of the HVS genome, as a nonintegrated circular episome, provided efficient sustained expression of a heterologous transgene. These in vivo results suggest that HVS-based vectors have potential for gene therapy applications.
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Affiliation(s)
- P G Smith
- Molecular Medicine Unit, University of Leeds, St James's University Hospital, UK
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Wang H, Fu X, Zhang X. Isomerization of a uniquely designed amplicon during herpes simplex virus-mediated replication. J Virol 2001; 75:10505-10. [PMID: 11581421 PMCID: PMC114627 DOI: 10.1128/jvi.75.21.10505-10510.2001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Herpes simplex virus (HSV) type 1 DNA isomerization was studied using a uniquely designed amplicon that mimics the viral genomic structure. The results revealed that amplicon concatemers frequently contain adjacent amplicon units with their segments in opposed orientations. These unusual concatemers were generated through homologous recombination, which does not require HSV DNA as the source of homology.
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Affiliation(s)
- H Wang
- Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, Texas 77030, USA
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