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Dogrammatzis C, Waisner H, Kalamvoki M. "Non-Essential" Proteins of HSV-1 with Essential Roles In Vivo: A Comprehensive Review. Viruses 2020; 13:E17. [PMID: 33374862 PMCID: PMC7824580 DOI: 10.3390/v13010017] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 12/17/2020] [Accepted: 12/18/2020] [Indexed: 12/19/2022] Open
Abstract
Viruses encode for structural proteins that participate in virion formation and include capsid and envelope proteins. In addition, viruses encode for an array of non-structural accessory proteins important for replication, spread, and immune evasion in the host and are often linked to virus pathogenesis. Most virus accessory proteins are non-essential for growth in cell culture because of the simplicity of the infection barriers or because they have roles only during a state of the infection that does not exist in cell cultures (i.e., tissue-specific functions), or finally because host factors in cell culture can complement their absence. For these reasons, the study of most nonessential viral factors is more complex and requires development of suitable cell culture systems and in vivo models. Approximately half of the proteins encoded by the herpes simplex virus 1 (HSV-1) genome have been classified as non-essential. These proteins have essential roles in vivo in counteracting antiviral responses, facilitating the spread of the virus from the sites of initial infection to the peripheral nervous system, where it establishes lifelong reservoirs, virus pathogenesis, and other regulatory roles during infection. Understanding the functions of the non-essential proteins of herpesviruses is important to understand mechanisms of viral pathogenesis but also to harness properties of these viruses for therapeutic purposes. Here, we have provided a comprehensive summary of the functions of HSV-1 non-essential proteins.
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Affiliation(s)
| | | | - Maria Kalamvoki
- Department of Microbiology, Molecular Genetics, and Immunology, University of Kansas Medical Center, Kansas City, KS 66160, USA; (C.D.); (H.W.)
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Bolhassani A, Jafarzade BS, Mardani G. In vitro and in vivo delivery of therapeutic proteins using cell penetrating peptides. Peptides 2017; 87:50-63. [PMID: 27887988 DOI: 10.1016/j.peptides.2016.11.011] [Citation(s) in RCA: 150] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 11/18/2016] [Accepted: 11/21/2016] [Indexed: 02/07/2023]
Abstract
The failure of proteins to penetrate mammalian cells or target tumor cells restricts their value as therapeutic tools in a variety of diseases such as cancers. Recently, protein transduction domains (PTDs) or cell penetrating peptides (CPPs) have been shown to promote the delivery of therapeutic proteins or peptides into live cells. The successful delivery of proteins mainly depends on their physicochemical properties. Although, linear cell penetrating peptides are one of the most effective delivery vehicles; but currently, cyclic CPPs has been developed to potently transport bioactive full-length proteins into cells. Up to now, several small protein transduction domains from viral proteins including Tat or VP22 could be fused to other peptides or proteins to entry them in various cell types at a dose-dependent approach. A major disadvantage of PTD-fusion proteins is primary uptake into endosomal vesicles leading to inefficient release of the fusion proteins into the cytosol. Recently, non-covalent complex formation (Chariot) between proteins and CPPs has attracted a special interest to overcome some delivery limitations (e.g., toxicity). Many preclinical and clinical trials of CPP-based delivery are currently under evaluation. Generally, development of more efficient protein transduction domains would significantly increase the potency of protein therapeutics. Moreover, the synergistic or combined effects of CPPs with other delivery systems for protein/peptide drug delivery would promote their therapeutic effects in cancer and other diseases. In this review, we will describe the functions and implications of CPPs for delivering the therapeutic proteins or peptides in preclinical and clinical studies.
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Affiliation(s)
- Azam Bolhassani
- Department of Hepatitis and AIDS, Pasteur Institute of Iran, Tehran, Iran.
| | | | - Golnaz Mardani
- Department of Hepatitis and AIDS, Pasteur Institute of Iran, Tehran, Iran
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Tang Y, Li J, Zhao S, Liu J. Killing Effect of the Herpes Simplex Virus Thymidine Kinase/Ganciclovir Enzyme/Prodrug System on Human Nasopharyngeal Carcinoma Cells. J Int Med Res 2016; 35:433-41. [PMID: 17697519 DOI: 10.1177/147323000703500401] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
A promising new approach for the gene therapy of cancer is the introduction of the herpes simplex virus thymidine kinase (HSV tk) gene into tumour cells, where the HSV tk gene product converts the non-toxic prodrug ganciclovir (GCV) into its cytotoxic metabolite. We constructed a recombinant plasmid containing the HSV tk gene using standard molecular biology techniques in order to investigate whether the HSV tk/GCV enzyme/prodrug system could kill the human nasopharyngeal carcinoma cell line HNE-1. The recombinant plasmid pcDNA3.1(–) CMV.TK was transfected into the HNE-1 cells by electroporation. The expression of HSV tk by the transfected HNE-1/TK cells was confirmed by mRNA amplification and Western blotting. The growth of HNE-1/TK cells was inhibited by GCV in a dose-dependent manner. The HSV tk/GCV system also demonstrated a considerable bystander effect on co-cultured wild type HNE-1 cells. We conclude that the HSV tk/GCV system could be used as gene therapy for nasopharyngeal carcinoma.
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Affiliation(s)
- Y Tang
- ENT Department, Xiangya Hospital, Central South University, Changsha, Hunan Province, China.
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Jin G, Zhou Y, Chai Q, Zhu G, Xu F, Liu F. VP22 and cytosine deaminase fusion gene modified tissue-engineered neural stem cells for glioma therapy. J Cancer Res Clin Oncol 2012. [PMID: 23180018 DOI: 10.1007/s00432-012-1347-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PURPOSE The herpes simplex virus type 1 tegument protein VP22 has the remarkable property of intercellular trafficking, thus making it a promising tool for improving gene transfer efficiency. METHODS To investigate whether the fusion of VP22 to the cytosine deaminase (CD) suicide gene could enhance the therapeutic efficiency of neural stem cells (NSCs) in the treatment for C6 glioma, the lentiviral vectors pHIV-VP(22)-EGFP, pHIV-CD, and pHIV-VP(22)-CD were constructed based on the pHIV-EGFP vector. After packaging, vectors were transduced into rat NSCs. RESULTS Fluorescence-activated cell sorting analysis revealed that the fusion of VP22-EGFP increased the expression rate of EGFP in NSCs compared with lenti-EGFP transduced cells. Under incubation with the prodrug 5-fluorocytosine (5-FC), the survival rates of C6 cells co-cultured with NSCs/VP(22)-CD (NSCs transduced with lenti-VP(22)-CD) decreased tremendously compared with those of C6 and NSCs/CD. Similar results were also observed in vivo; a significant reduction in tumor volumes in C6 glioma-bearing rats was observed in the NSCs/VP(22)-CD therapy group when compared with other control groups. CONCLUSIONS Our results reveal that VP22 increases the transduction efficiency of lentivirus into NSCs and enhances the therapeutic efficacy of CD-engineered rat NSCs in the treatment for C6 glioma, demonstrating that VP22 might be a useful tool for the gene therapy of engineered NSCs and providing a potential novel strategy for enhancing the effectiveness of gene therapy in other diseases.
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Affiliation(s)
- Guishan Jin
- Brain Tumor Research Center, Department of Neurosurgery, Beijing Neurosurgical Institute, Beijing Tiantan Hospital, Capital Medical University, Tiantan Xili 6, Chongwen District, Beijing 100050, People's Republic of China
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Jin GS, Zhu GD, Zhao ZG, Liu FS. VP22 enhances the expression of glucocerebrosidase in human Gaucher II fibroblast cells mediated by lentiviral vectors. Clin Exp Med 2011; 12:135-43. [DOI: 10.1007/s10238-011-0152-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 06/29/2011] [Indexed: 01/17/2023]
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Nuclear drug delivery to target tumour cells. Eur J Pharmacol 2009; 625:174-80. [DOI: 10.1016/j.ejphar.2009.06.069] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2009] [Revised: 06/05/2009] [Accepted: 06/22/2009] [Indexed: 01/12/2023]
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Sverdlov ED. Not gene therapy, but genetic surgery-the right strategy to attack cancer. MOLECULAR GENETICS, MICROBIOLOGY AND VIROLOGY : MOLEKULYARNAYA GENETIKA, MIKROBIOLOGIYA I VIRUSOLOGIYA 2009; 24:93-113. [PMID: 32214647 PMCID: PMC7089455 DOI: 10.3103/s089141680903001x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In this review, I will suggest to divide all the approaches united now under common term "gene therapy" into two broad strategies of which the first one uses the methodology of targeted therapy with all its characteristics, but with genes in the role of agents targeted at a certain molecular component(s) presumably crucial for cancer maintenance. In contrast, the techniques of the other strategy are aimed at the destruction of tumors as a whole using the features shared by all cancers, for example relatively fast mitotic cell division or active angiogenesis. While the first strategy is "true" gene therapy, the second one is more like genetic surgery when a surgeon just cuts off a tumor with his scalpel and has no interest in knowing delicate mechanisms of cancer emergence and progression. I will try to substantiate the idea that the last strategy is the only right one, and its simplicity is paradoxically adequate to the super-complexity of tumors that originates from general complexity of cell regulation, strongly disturbed in tumor cells, and especially from the complexity of tumors as evolving cell populations, affecting also their ecological niche formed by neighboring normal cells and tissues. An analysis of the most widely used for such a "surgery" suicide gene/prodrug combinations will be presented in some more details.
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Affiliation(s)
- E D Sverdlov
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry RAN, Moscow, Russia
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Beerens AMJ, Rots MG, Bermúdez B, de Vries EFJ, Haisma HJ. Secretion of thymidine kinase to increase the effectivity of suicide gene therapy results in the loss of enzymatic activity. J Drug Target 2008; 16:26-35. [PMID: 18172817 DOI: 10.1080/10611860701637768] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Low efficiency of gene transfer is one of the major limitations of gene therapy. A solution to this problem may be transmission; by modification of the transgene, the gene product can be secreted and internalized by the surrounding cells. Cancer gene therapy using the herpes simplex thymidine kinase (HSV-TK) suicide gene is a promising treatment, and TK has been used in clinical trials with some success. However, this kind of therapy has limited efficacy due to the low level of gene transfer reached. A modified TK protein, capable of migrating from the producing cell to neighboring cells, would result in a greater proportion of cells affected by the treatment. As a first step towards transmission, we constructed a secretory form of HSV-TK by including the Igkappa leader peptide in the gene. An endoplasmatic reticulum export signal was added to the construct to further improve its secretion. Secretion and protein production in cancer cells, the enzymatic activity of the modified proteins and the ability of the modified TK to sensitize cancer cells to ganciclovir were tested. Addition of the Igkappa leader resulted in high levels of secretion of HSV-TK, with up to 70% of the total amount of protein secreted. Inclusion of an ER export signal did not further improve secretion. The enzyme activity of the secreted TK however, was decreased when compared to native TK. This study is the first to report on secretion of TK, and provides a first step in a novel strategy to improve the efficiency of cancer gene therapy. The loss of function in secreted TK however, may present a major hurdle in the development of a transmitted form of TK.
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Affiliation(s)
- A M J Beerens
- Department of Therapeutic Gene Modulation, University Centre for Pharmacy, University of Groningen, Groningen, The Netherlands
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Wei MQ, Ren R, Good D, Anné J. Clostridial spores as live 'Trojan horse' vectors for cancer gene therapy: comparison with viral delivery systems. GENETIC VACCINES AND THERAPY 2008; 6:8. [PMID: 18279524 PMCID: PMC2267465 DOI: 10.1186/1479-0556-6-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/21/2007] [Accepted: 02/17/2008] [Indexed: 01/14/2023]
Abstract
Solid tumours account for 90% of all cancers. Gene therapy represents a potential new modality for their treatment. Up to now, several approaches have been developed, but the most efficient ones are the viral vector based gene therapy systems. However, viral vectors suffer from several deficiencies: firstly most vectors currently in use require intratumoural injection to elicit an effect. This is far from ideal as many tumours are inaccessible and many may have already spread to other parts of the body, making them difficult to locate and inject gene therapy vectors into. Second, because of cell heterogeneity within a given cancer, the vectors do not efficiently enter and kill every cancer cell. Third, hypoxia, a prevalent characteristic feature of most solid tumours, reduces the ability of the viral vectors to function and decreases viral gene expression and production. Consequently, a proportion of the tumour is left unaffected, from which tumour regrowth occurs. Thus, cancer gene therapy has yet to realise its full potential. The facultative or obligate anaerobic bacteria have been shown to selectively colonise and regerminate in solid tumours when delivered systemically. Among them, the clostridial spores were easy to produce, stable to store and safe to use as well as having extensive oncolytic ability. However, research in animals and humans has shown that oncolysis was almost always interrupted sharply at the outer rim of the viable tumour tissue where the blood supply was sufficient. These clostridial spores, though, could serve as "Trojan horse" for cancer gene therapy. Indeed, various spores harbouring genes for cancerstatic factors, prodrug enzymes, or proteins or cytokines had endowed with additional tumour-killing capability. Furthermore, combination of these "Trojan horses" with conventional chemotherapy or radiation therapies often significantly perform better, resulting in the "cure" of solid tumours in a high percentage of animals. It is, thus, not too difficult to predict the potential outcomes for the use of clostridial spores as "Trojan horse" vectors for oncolytic therapy when compared with viral vector-mediated cancer therapy for it be replication-deficient or competent. However, to move the "Trojan horse" to a clinic, though, additional requirements need to be satisfied (i) target tumours only and not anywhere else, and (ii) be able to completely kill primary tumours as well as metastases. Current technologies are in place to achieve these goals.
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Affiliation(s)
- Ming Q Wei
- Department of Medicine, University of Queensland, Prince Charles Hospital, Brisbane, Queensland, 4032, Australia
- Division of Molecular and Gene Therapies, Griffith Institute for Health and Medical Research, GH1, Griffith University, Gold Coast, Queensland, 4222, Australia
| | - Ruimei Ren
- Department of Medicine, University of Queensland, Prince Charles Hospital, Brisbane, Queensland, 4032, Australia
- Division of Molecular and Gene Therapies, Griffith Institute for Health and Medical Research, GH1, Griffith University, Gold Coast, Queensland, 4222, Australia
- Tumour Hospital, Shandong Academy of Medical Sciences, Jinan, Shandong Province, PR China
| | - David Good
- Department of Medicine, University of Queensland, Prince Charles Hospital, Brisbane, Queensland, 4032, Australia
- Division of Molecular and Gene Therapies, Griffith Institute for Health and Medical Research, GH1, Griffith University, Gold Coast, Queensland, 4222, Australia
| | - Jozef Anné
- Rega Institute for Medical Research, Minderbroedersstraat 10, B-3000 Leuven, Belgium
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Torchilin V. Intracellular delivery of protein and peptide therapeutics. DRUG DISCOVERY TODAY. TECHNOLOGIES 2008; 5:e95-e103. [PMID: 24981097 DOI: 10.1016/j.ddtec.2009.01.002] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Many proteins and peptides are used as highly specific and effective therapeutic agents. Their use is, however, complicated by their instability and side effects. Because many protein and peptide drugs have their therapeutic targets inside cells, there is also an important task to bring these drugs into target cells without subjecting them to the lysosomal degradation. This review describes current approaches to the intracellular delivery of protein and peptide drugs. Various drug delivery systems and methods are considered allowing for safe and effective transport of protein and peptide drugs into the cell cytoplasm.:
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Affiliation(s)
- Vladimir Torchilin
- Department of Pharmaceutical Sciences and Center for Pharmaceutical Biotechnology and Nanomedicine, Northeastern University, 360 Huntington Avenue, Boston, MA 02115, USA.
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12
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Luo C, Mori I, Goshima F, Ushijima Y, Nawa A, Kimura H, Nishiyama Y. Replication-competent, oncolytic herpes simplex virus type 1 mutants induce a bystander effect following ganciclovir treatment. J Gene Med 2007; 9:875-83. [PMID: 17685493 DOI: 10.1002/jgm.1085] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Cells expressing herpes simplex virus (HSV) thymidine kinase (tk) are killed by ganciclovir (GCV). Adjacent cells without HSV-tk also die, a phenomenon known as the 'bystander effect'. However, there is no evidence that replication-competent HSV induces a bystander effect in the presence of GCV. Therefore, we investigated the bystander effect in HEp-2 cells infected with replication-competent, oncolytic HSV-1 mutants, hrR3 and HF10. In cells infected at a multiplicity of infection (MOI) of 3, GCV did not induce apoptosis. At low MOIs of 0.3 and 0.03, however, a number of adjacent, uninfected cells apoptosed following GCV treatment. Irrespective of GCV treatment, HEp-2 cells expressed minimal levels of connexin 43 (Cx43). However, Cx43 expression was enhanced by GCV in response to infection with HF10 at an MOI of 0.3, but not at an MOI of 3. Expression of other proteins involved in gap junctions, including Cx26 and Cx40, was not augmented under these conditions. The PKA and PI3K signal transduction pathways are likely involved in enhanced Cx43 expression as inhibitors of these pathways prevented Cx43 upregulation. These results suggest that infection with replication-competent HSV-1 induces the bystander effect in cells treated with GCV because of efficient intercellular transport of active GCV through abundant gap junctions.
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Affiliation(s)
- Chenhong Luo
- Department of Virology, Nagoya University Graduate School of Medicine, Tsuruma, Nagoya 466-8550, Japan
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Medina-Kauwe LK. "Alternative" endocytic mechanisms exploited by pathogens: new avenues for therapeutic delivery? Adv Drug Deliv Rev 2007; 59:798-809. [PMID: 17707545 PMCID: PMC2040389 DOI: 10.1016/j.addr.2007.06.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2007] [Accepted: 06/12/2007] [Indexed: 11/22/2022]
Abstract
Some pathogens utilize unique routes to enter cells that may evade the intracellular barriers encountered by the typical clathrin-mediated endocytic pathway. Retrograde transport and caveolar uptake are among the better characterized pathways, as alternatives to clathrin-mediated endocytosis, that are known to facilitate entry of pathogens and potential delivery agents. Recent characterization of the trafficking mechanisms of prion proteins and certain bacteria may present new paradigms for strategizing improvements in therapeutic spread and retention of therapy. This review will provide an overview of such endocytic pathways, and discuss current and future possibilities in using these routes as a means to improve therapeutic delivery.
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Luo C, Nawa A, Yamauchi Y, Kohno S, Ushijima Y, Goshima F, Kikkawa F, Nishiyama Y. Intercellular trafficking and cytotoxicity of recombinant HSV-1 thymidine kinase fused with HSV-2 US11 RXP repeat peptide. Virus Genes 2007; 34:263-72. [PMID: 16927131 DOI: 10.1007/s11262-006-0013-8] [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] [Received: 02/13/2006] [Accepted: 04/18/2006] [Indexed: 11/30/2022]
Abstract
To improve the therapeutic efficacy of herpes simplex virus type 1 (HSV-1) thymidine kinase (tk)/ganciclovir (GCV) therapy, we have made recombinant tk chimeras fused with the arginine-rich (RXP) repeat of herpes simplex virus type 2 (HSV-2) US11 and examined their activity of intercellular trafficking and cytotoxicity. When examined the immunofluorescence staining patterns of RXP/tk fusion proteins in transfected COS7 cells, the RXP chimeras revealed a conservation of the trafficking activity of RXP. We also found that transfection of tkC Delta 6-RXP (lacking the C-terminal six amino residues of tk), tk-RXP, and tkN Delta 66-RXP (lacking the N-terminal 66 amino residues of tk) induced apoptosis even in the absence of GCV. The results suggest that these tk/RXP chimeras themselves have apoptosis-inducing activity, and that the HSV tk nucleoside-binding domain may be involved in the induction of apoptosis. Furthermore, treatment with 5 muM GCV induced efficient cell death in cells tranfected with tk-RXP in comparison to the cells transfected with tk (P < 0.0001).
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Affiliation(s)
- Chenhong Luo
- Department of Virology, Nagoya University Graduate School of Medicine, Tsurumai-cho 65, showa-ku, 466-8550, Nagoya, Japan
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Torchilin VP. Targeted pharmaceutical nanocarriers for cancer therapy and imaging. AAPS JOURNAL 2007; 9:E128-47. [PMID: 17614355 PMCID: PMC2751402 DOI: 10.1208/aapsj0902015] [Citation(s) in RCA: 550] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The use of various pharmaceutical nanocarriers has become one of the most important areas of nanomedicine. Ideally, such carriers should be specifically delivered (targeted) to the pathological area to provide the maximum therapeutic efficacy. Among the many potential targets for such nanocarriers, tumors have been most often investigated. This review attempts to summarize currently available information regarding targeted pharmaceutical nanocarriers for cancer therapy and imaging. Certain issues related to some popular pharmaceutical nanocarriers, such as liposomes and polymeric micelles, are addressed, as are different ways to target tumors via specific ligands and via the stimuli sensitivity of the carriers. The importance of intracellular targeting of drug- and DNA-loaded pharmaceutical nanocarriers is specifically discussed, including intracellular delivery with cell-penetrating peptides.
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Affiliation(s)
- Vladimir P Torchilin
- Department of Pharmaceutical Sciences and Center for Pharmaceutical Biotechnology and Nanomedicine, Northeastern University, Boston, MA 02115, USA.
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Chauhan A, Tikoo A, Kapur AK, Singh M. The taming of the cell penetrating domain of the HIV Tat: myths and realities. J Control Release 2006; 117:148-62. [PMID: 17196289 PMCID: PMC1859861 DOI: 10.1016/j.jconrel.2006.10.031] [Citation(s) in RCA: 130] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2006] [Accepted: 10/20/2006] [Indexed: 01/08/2023]
Abstract
Protein transduction with cell penetrating peptides over the past several years has been shown to be an effective way of delivering proteins in vitro and now several reports have also shown valuable in vivo applications in correcting disease states. An impressive bioinspired phenomenon of crossing biological barriers came from HIV transactivator Tat protein. Specifically, the protein transduction domain of HIV Tat has been shown to be a potent pleiotropic peptide in protein delivery. Various approaches such as molecular modeling, arginine guanidinium head group structural strategy, multimerization of PTD sequence and phage display system have been applied for taming of the PTD. This has resulted in identification of PTD variants which are efficient in cell membrane penetration and cytoplasmic delivery. In spite of these state of the art technologies, the dilemma of low protein transduction efficiency and target specific delivery of PTD fusion proteins remains unsolved. Moreover, some misconceptions about PTD of Tat in the literature require considerations. We have assembled critical information on secretory, plasma membrane penetration and transcellular properties of Tat and PTD using molecular analysis and available experimental evidences.
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Affiliation(s)
- Ashok Chauhan
- Department of Neurology, Richard Johnson Division of Neuroimmunology and Neurological Infections, Johns Hopkins University, 509 Pathology, Baltimore, MD 21287, USA.
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Lumniczky K, Sáfrány G. Cancer gene therapy: Combination with radiation therapy and the role of bystander cell killing in the anti-tumor effect. Pathol Oncol Res 2006; 12:118-24. [PMID: 16799716 DOI: 10.1007/bf02893457] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2005] [Accepted: 04/20/2006] [Indexed: 11/28/2022]
Abstract
Current anti-cancer modalities such as surgery, chemo- and radiation therapies have only limited success in cancer treatment. Gene therapy is a promising new tool to improve outcomes. In this review, first we summarize the various strategies to kill tumor cells, and then focus on the bystander effect of gene therapy. A variety of strategies, such as gene-directed enzyme pro-drug therapy, activation of an anti-tumor immune attack, application of replication-competent and oncolytic viral vectors, tumor-specific as well as radiation- and hypoxiainduced gene expression, might be applied to target tumor cells. We put special emphasis on the combination of these approaches with local tumor irradiation. Using the available vector systems, only a small portion of cancer cells contains the therapeutic genes under clinical situations. However, cells directly targeted by gene therapy will transfer death signals to neighboring cancer cells. This bystander cell killing improves the efficiency of cancer gene therapy. Death signals are delivered by cell-to-cell communication through gap junction intercellular contacts, release of toxic metabolites into the neighborhood or to larger distances, phagocytosis of apoptotic bodies, and the activation of the immune system. Bystander cell killing can be enhanced by the introduction of gap junction proteins into cells, by further activating the immune system with immune-stimulatory molecules, or by introducing genes that help the transfer of cytotoxic genes and/or metabolites into bystander cells. In conclusion, although bystander cell killing can improve therapeutic effects, there should be additional developments in cancer gene therapy for a more efficient clinical application.
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Affiliation(s)
- Katalin Lumniczky
- Department of Molecular and Tumor Radiobiology, National Research Institute for Radiobiology and Radiohygiene, Budapest, H-1221, Hungary
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Graepler F, Lemken ML, Wybranietz WA, Schmidt U, Smirnow I, Gross CD, Spiegel M, Schenk A, Graf H, Lauer UA, Vonthein R, Gregor M, Armeanu S, Bitzer M, Lauer UM. Bifunctional chimeric SuperCD suicide gene -YCD: YUPRT fusion is highly effective in a rat hepatoma model. World J Gastroenterol 2006; 11:6910-9. [PMID: 16437592 PMCID: PMC4717030 DOI: 10.3748/wjg.v11.i44.6910] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM To investigate the effects of catalytically superior gene-directed enzyme prodrug therapy systems on a rat hepatoma model. METHODS To increase hepatoma cell chemosensitivity for the prodrug 5-fluorocytosine (5-FC), we generated a chimeric bifunctional SuperCD suicide gene, a fusion of the yeast cytosine deaminase (YCD) and the yeast uracil phosphoribosyltransferase (YUPRT) gene. RESULTS In vitro stably transduced Morris rat hepatoma cells (MH) expressing the bifunctional SuperCD suicide gene (MH SuperCD) showed a clearly marked enhancement in cell killing when incubated with 5-FC as compared with MH cells stably expressing YCD solely (MH YCD) or the cytosine deaminase gene of bacterial origin (MH BCD), respectively. In vivo, MH SuperCD tumors implanted both subcutaneously as well as orthotopically into the livers of syngeneic ACI rats demonstrated significant tumor regressions (P<0.01) under both high dose as well as low dose systemic 5-FC application, whereas MH tumors without transgene expression (MH naive) showed rapid progression. For the first time, an order of in vivo suicide gene effectiveness (SuperCD>> YCD>>BCD>>>negative control) was defined as a result of a direct in vivo comparison of all three suicide genes. CONCLUSION Bifunctional SuperCD suicide gene expression is highly effective in a rat hepatoma model, thereby significantly improving both the therapeutic index and the efficacy of hepatocellular carcinoma killing by fluorocytosine.
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Affiliation(s)
- Florian Graepler
- Department of Internal Medicine I, Medical University Clinic Tübingen, Germany.
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Lee KC, Hamstra DA, Bullarayasamudram S, Bhojani MS, Moffat BA, Dornfeld KJ, Ross BD, Rehemtulla A. Fusion of the HSV-1 tegument protein vp22 to cytosine deaminase confers enhanced bystander effect and increased therapeutic benefit. Gene Ther 2006; 13:127-37. [PMID: 16163381 DOI: 10.1038/sj.gt.3302631] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2005] [Revised: 05/07/2005] [Accepted: 06/30/2005] [Indexed: 11/09/2022]
Abstract
A major limitation in cancer gene therapy, specifically gene-dependent enzyme prodrug therapy (GDEPT), is inefficient gene delivery and expression. The suicide gene cytosine deaminase (CD) and its substrate, 5-fluorocytosine (5-FC), have been extensively explored due to the inherent 'bystander' effect achieved through diffusion of the toxic metabolite 5-fluorouracil (5-FU). In this study, we aimed to enhance this 'bystander' effect by fusing the Saccharomyces cerevisiae CD to the HSV-1 tegument protein vp22, a novel translocating protein. Two constructs were created: one with vp22 fused to CD (vp22CD) and a second wherein a truncated vp22, lacking the necessary residues for trafficking, fused to CD (delvp22CD). The generated 9L stable lines exhibited similar growth rates, enzyme expression, CD activity, and sensitivity to 5-FC and 5-FU. However, mixed population colony formation assays demonstrated greater bystander effect with the vp22CD fusion as compared to delvp22CD. This enhancement was maintained in vivo where 9L tumors expressing 20 or 50% vp22CD exhibited increased growth delay compared to the respective delvp22CD tumors. Moreover, adenoviral transduction of established wild-type 9L tumors showed increased growth delay with vp22CD (Ad-EF_vp22CD) as compared to equivalent CD (Ad-EF_CD) transduced tumors. Finally, confirming the increased efficacy, (19)F magnetic resonance spectroscopy (MRS) of vp22CD-expressing tumors demonstrated increased 5-FU levels as compared to tumors expressing the nontranslocating CD. These results together demonstrated that fusion of vp22 to CD resulted in CD translocation, which in turn amplified conversion of 5-FC to 5-FU in vivo and enhanced the therapeutic benefit of this GDEPT strategy.
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Affiliation(s)
- K C Lee
- Department of Biological Chemistry, The University of Michigan Medical Center, Ann Arbor, 48109, USA
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20
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Sung M, Poon GMK, Gariépy J. The importance of valency in enhancing the import and cell routing potential of protein transduction domain-containing molecules. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2005; 1758:355-63. [PMID: 16442074 DOI: 10.1016/j.bbamem.2005.11.016] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2005] [Revised: 11/14/2005] [Accepted: 11/17/2005] [Indexed: 11/22/2022]
Abstract
Protein transduction domains (PTDs) are peptides that afford the internalization of cargo macromolecules (including plasmid DNA, proteins, liposomes, and nanoparticles). In the case of polycationic peptides, the efficiency of PTDs to promote cellular uptake is directly related to their molecular mass or their polyvalent presentation. Similarly, the efficiency of routing to the nucleus increases with the number of nuclear localization signals (NLS) associated with a cargo. The quantitative enhancement, however, depends on the identity of the PTD sequence as well as the targeted cell type. Thus the choice and multivalent presentation of PTD and NLS sequences are important criteria guiding the design of macromolecules intended for specific intracellular localization. This review outlines synthetic and recombinant strategies whereby PTDs and signal sequences can be assembled into multivalent peptide dendrimers and promote the uptake and routing of their cargoes. In particular, the tetramerization domain of the tumour suppressor p53 (p53tet) is emerging as a useful scaffold to present multiple routing and targeting moieties. Short cationic peptides fused to the 31-residue long p53tet sequence resulted in tetramers displaying a significant enhancement (up to 1000 fold) in terms of their ability to be imported into cells and delivered to the cell nucleus in relation to their monomeric analogues. The design of future polycationic peptide dendrimers as effective delivering vehicles will need to incorporate selective cell targeting functions and provide solutions to the issue of endosomal entrapment.
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Affiliation(s)
- Michael Sung
- Department of Medical Biophysics, University of Toronto, Ontario Cancer Institute, Princess Margaret Hospital, 610 University Avenue, Toronto, Canada M5G 2M9
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21
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Zavaglia D, Lin EH, Guidetti M, Pluquet O, Hainaut P, Favrot MC, Coll JL. Poor intercellular transport and absence of enhanced antiproliferative activity after non-viral gene transfer of VP22-P53 or P53-VP22 fusions into p53 null cell lines in vitro or in vivo. J Gene Med 2005; 7:936-44. [PMID: 15754307 DOI: 10.1002/jgm.741] [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: 11/11/2022] Open
Abstract
BACKGROUND The herpes simplex virus type 1 (HSV-1) VP22 protein has the property to mediate intercellular trafficking of heterologous proteins fused to its C- or N-terminus. We have previously shown improved delivery and enhanced therapeutic effect in vitro and in vivo with a P27-VP22 fusion protein. In this report, we were interested in studying the spread and biological activity of VP22 fused to the P53 tumor suppressor. METHODS Expression of the VP22-P53 and P53-VP22 fusion proteins was shown by Western blot and intercellular spreading was monitored by immunofluorescence on transiently transfected cells. In vitro antiproliferative activity of wild-type (wt) P53 and P53-VP22 was assessed by proliferation assays and transactivating ability was studied by a reporter gene test and a gel-shift assay. Antitumor activity was also tested in vivo by intratumoral injections of naked DNA in a model of subcutaneous tumors implanted in nude mice. RESULTS Our results show that the C-terminal fusion or the N-terminal P53-VP22 fusion proteins are not able to spread as efficiently as VP22. Moreover, we demonstrate that VP22-P53 does not possess any transactivating ability. P53-VP22 has an antiproliferative activity, but this activity is not superior to the one of P53 alone, in vitro or in vivo. CONCLUSIONS Our study indicates that a gene transfer strategy using VP22 cannot be considered as a universal system to improve the delivery of any protein.
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Affiliation(s)
- David Zavaglia
- Groupe de Recherche sur le Cancer du Poumon, INSERM U578, Institut Albert Bonniot, 38706 La Tronche, France
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Hakkarainen T, Wahlfors T, Meriläinen O, Loimas S, Hemminki A, Wahlfors J. VP22 does not significantly enhance enzyme prodrug cancer gene therapy as a part of a VP22-HSVTk-GFP triple fusion construct. J Gene Med 2005; 7:898-907. [PMID: 15759279 DOI: 10.1002/jgm.737] [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: 11/11/2022] Open
Abstract
BACKGROUND VP22 is a herpes simplex virus type 1 (HSV-1) tegument protein that has been suggested to spread from cell to cell, alone or as a part of fusion proteins. Creating controversy, some reports indicate that VP22 cannot facilitate significant intercellular spreading. To study the capacity of VP22 to cause spreading and enhance thymidine kinase/ganciclovir cancer gene therapy, we constructed a novel triple fusion protein containing VP22, HSV thymidine kinase and green fluorescent protein (VP22-Tk-GFP). This fusion protein has three functional domains in the same polypeptide, thus making it possible to reliably compare the causality between transduction rate and cell killing efficiency in vitro and in vivo. METHODS VP22-Tk-GFP was cloned into lenti- and adenoviral vectors and used for expression studies, analyses for VP22-mediated protein spreading, and to study the effect of VP22 to thymidine kinase/ganciclovir-mediated cytotoxicity. The function of VP22-Tk-GFP was also investigated in vivo. RESULTS The triple fusion protein was expressed correctly in vitro, but intercellular trafficking was not observed in any of the studied cell lines. However, under certain conditions, VP22-Tk-GFP sensitized cells more efficiently to ganciclovir than Tk-GFP. In vivo there was a trend for increased inhibition of tumor growth with VP22-Tk-GFP when ganciclovir was present, but the difference with Tk-GFP was not statistically significant. CONCLUSIONS Based on our results, VP22 fusion proteins do not seem to traffic intercellularly at detectable levels in most tumor cell types. Even though VP22 enhanced cytotoxicity in one cell line in vitro, the effect in vivo was modest. Therefore, our results do not support the utility of VP22 as an enhancer of enzyme prodrug cancer gene therapy.
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Affiliation(s)
- Tanja Hakkarainen
- A. I. Virtanen Institute, Department of Biotechnology and Molecular Medicine, University of Kuopio, FIN-70211 Kuopio, Finland
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23
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Hillemann A, Brandenburg B, Schmidt U, Roos M, Smirnow I, Lemken ML, Lauer UM, Hildt E. Protein transduction with bacterial cytosine deaminase fused to the TLM intercellular transport motif induces profound chemosensitivity to 5-fluorocytosine in human hepatoma cells. J Hepatol 2005; 43:442-50. [PMID: 15922474 DOI: 10.1016/j.jhep.2005.02.031] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2004] [Revised: 02/12/2005] [Accepted: 02/16/2005] [Indexed: 01/09/2023]
Abstract
BACKGROUND/AIMS This study investigates the application of protein based therapeutic suicide enzyme/prodrug approaches providing novel means for both safe and effective local therapeutic regimes in solid tumors. METHODS Employing a novel cell permeable peptide, known as the translocation motif (TLM) of hepatitis B virus, E. coli cytosine deaminase (BCDase) suicide fusion proteins were generated. RESULTS TLM fusion proteins formed hexamers (as do parental wtBCDase proteins) and retained the specific enzymatic activity of cytosine conversion to uracil also being comparable to parental wtBCDase proteins. However, only BCDase-TLM fusion proteins, but not TLM-BCDase fusion nor parental wtBCDase proteins were found to be taken up to the cytoplasm of target cells as demonstrated both by confocal laser scanning microscopy and cell fractionation. Uptake of BCDase-TLM worked both efficiently and rapidly and was found to be independent from the endosomal pathway. Since BCDase-TLM fusion proteins completely retained their suicide enzymatic activity in the course of translocation across the plasma membrane their usage as profound inducers of chemo-sensitivity to 5-FC strongly is suggested. CONCLUSIONS Future therapeutic local application of cell-permeable BCDase-TLM fusion proteins together with a systemic 5-FC prodrug application could result in profound antitumor activities without apparent side effects.
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24
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Zhang M, Zhang X, Bai CX, Song XR, Chen J, Gao L, Hu J, Hong QY, West MJ, Wei MQ. Silencing the epidermal growth factor receptor gene with RNAi may be developed as a potential therapy for non small cell lung cancer. GENETIC VACCINES AND THERAPY 2005; 3:5. [PMID: 15987532 PMCID: PMC1187910 DOI: 10.1186/1479-0556-3-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/04/2005] [Accepted: 06/30/2005] [Indexed: 11/10/2022]
Abstract
Lung cancer has emerged as a leading cause of cancer death in the world. Non-small cell lung cancer (NSCLC) accounts for 75-80% of all lung cancers. Current therapies are ineffective, thus new approaches are needed to improve the therapeutic ratio. Double stranded RNA (dsRNA)-mediated RNA interference (RNAi) has shown promise in gene silencing, the potential of which in developing new methods for the therapy of NSCLC needs to be tested. We report here RNAi induced effective silencing of the epidermal growth factor receptor (EGFR) gene, which is over expressed in NSCLC. NSCLC cell lines A549 and SPC-A1 were transfected with sequence- specific dsRNA as well as various controls. Immune fluorescent labeling and flow cytometry were used to monitor the reduction in the production of EGFR protein. Quantitative reverse-transcriptase PCR was used to detect the level of EGFR mRNA. Cell count, colony assay, scratch assay, MTT assay in vitro and tumor growth assay in athymic nude mice in vivo were used to assess the functional effects of EGFR silencing on tumor cell growth and proliferation. Our data showed transfection of NSCLC cells with dsRNA resulted in sequence specific silencing of EGFR with 71.31% and 71.78 % decreases in EGFR protein production and 37.04% and 54.92% in mRNA transcription in A549 and SPC-A1 cells respectively. The decrease in EGFR protein production caused significant growth inhibition, i.e.: reducing the total cell numbers by 85.0% and 78.3%, and colony forming numbers by 63.3% and 66.8%. These effects greatly retarded the migration of NSCLC cells by more than 80% both at 24 h and at 48 h, and enhanced chemo-sensitivity to cisplatin by four-fold in A549 cells and seven-fold in SPC-A1. Furthermore, dsRNA specific for EGFR inhibited tumor growth in vivo both in size by 75.06% and in weight by 73.08%. Our data demonstrate a new therapeutic effect of sequence specific suppression of EGFR gene expression by RNAi, enabling inhibition of tumor proliferation and growth. However, in vivo use of dsRNA for gene transfer to tumor cells would be limited because dsRNA would be quickly degraded once delivered in vivo. We thus tested a new bovine lentiviral vector and showed lentivector-mediated RNAi effects were efficient and specific. Combining RNAi with this gene delivery system may enable us to develop RNAi for silencing EGFR into an effective therapy for NSCLC.
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Affiliation(s)
- Min Zhang
- Department of Pulmonary Diseases, Zhong Shan Hospital, Fudan University, Shanghai, PR China
| | - Xin Zhang
- Department of Pulmonary Diseases, Zhong Shan Hospital, Fudan University, Shanghai, PR China
- Department of Medicine, University of Queensland, Prince Charles Hospital, Brisbane, Australia
| | - Chun-Xue Bai
- Department of Pulmonary Diseases, Zhong Shan Hospital, Fudan University, Shanghai, PR China
| | - Xian-Rang Song
- Department of Medicine, University of Queensland, Prince Charles Hospital, Brisbane, Australia
| | - Jie Chen
- Department of Pulmonary Diseases, Zhong Shan Hospital, Fudan University, Shanghai, PR China
| | - Lei Gao
- Department of Pulmonary Diseases, Zhong Shan Hospital, Fudan University, Shanghai, PR China
| | - Jie Hu
- Department of Pulmonary Diseases, Zhong Shan Hospital, Fudan University, Shanghai, PR China
| | - Qun-Ying Hong
- Department of Pulmonary Diseases, Zhong Shan Hospital, Fudan University, Shanghai, PR China
| | - Malcolm J West
- Department of Medicine, University of Queensland, Prince Charles Hospital, Brisbane, Australia
| | - Ming Q Wei
- Department of Medicine, University of Queensland, Prince Charles Hospital, Brisbane, Australia
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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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26
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Roy V, Qiao J, de Campos-Lima P, Caruso M. Direct evidence for the absence of intercellular trafficking of VP22 fused to GFP or to the herpes simplex virus thymidine kinase. Gene Ther 2005; 12:169-76. [PMID: 15483667 DOI: 10.1038/sj.gt.3302394] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The treatment of solid tumors by retroviral delivery of the herpes simplex virus thymidine kinase (TK) followed by ganciclovir (GCV) treatment has so far shown only limited success in patients. One major drawback in this approach is the lack of efficient in vivo gene delivery to cancer cells. Although, the transduction of every single tumor cell is not a requirement since the bystander effect (BE) mediated by gap junctions allows the diffusion of the toxic GCV metabolites from TK-expressing cells toward untransduced cells. To render the TK/GCV approach more potent, and independent of the level of gap junctions, we have tested the efficiency of a TK mutant (TK30) fused to VP22, a herpes simplex protein that seems to be capable of intercellular trafficking. We failed to detect an increase in the BE with cells expressing VP22 fused to TK30 versus cells containing TK30 alone, and this result forced us to reinvestigate the trafficking properties of VP22. Using very sensitive Western blot and fluorescence assays, we were not able to detect the spread of VP22 fused either to TK30 or GFP. These results indicate that VP22 cannot be used as a cargo to translocate TK30 or GFP.
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Affiliation(s)
- V Roy
- Le Centre de Recherche en Cancérologie de l'Université Laval, L'Hôtel-Dieu de Québec, Centre Hospitalier Universitaire de Québec, Québec, Canada
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Perkins SD, Hartley MG, Lukaszewski RA, Phillpotts RJ, Stevenson FK, Bennett AM. VP22 enhances antibody responses from DNA vaccines but not by intercellular spread. Vaccine 2005; 23:1931-40. [PMID: 15734065 DOI: 10.1016/j.vaccine.2004.10.033] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2004] [Accepted: 10/18/2004] [Indexed: 11/29/2022]
Abstract
In some species DNA vaccines elicit potent humoral and cellular immune responses. However, their performance in humans and non-human primates is less impressive. There are suggestions in the literature that an increase in the intercellular distribution of protein expressed from a DNA vaccine may enhance immunogenicity. We incorporated the Herpes Simplex Virus type 1 (HSV) VP22 gene, which encodes a protein that has been described as promoting intercellular spread, into a DNA vector in which it was fused to enhanced green fluorescent protein (EGFP). Following transfection of the plasmid DNA into mammalian cells, distribution of the fusion protein VP22-EGFP was not increased compared to EGFP alone. Furthermore, we found no evidence to suggest that VP22 was capable of mediating intercellular spread. However, when these constructs were used as DNA vaccines to immunise mice, antibody levels specific to EGFP were significantly enhanced when EGFP was fused to VP22. These data suggest that amplification of the immune response may occur via mechanisms other than VP22-mediated intercellular spread of antigen.
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Affiliation(s)
- Stuart D Perkins
- Biomedical Sciences Department, Defence Science and Technology Laboratory, Porton Down, Salisbury, Wiltshire SP4 OJQ, UK.
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28
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Prasmickaite L, Høgset A, Olsen VM, Kaalhus O, Mikalsen SO, Berg K. Photochemically enhanced gene transfection increases the cytotoxicity of the herpes simplex virus thymidine kinase gene combined with ganciclovir. Cancer Gene Ther 2005; 11:514-23. [PMID: 15118758 DOI: 10.1038/sj.cgt.7700720] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Tumor targeting is an important issue in cancer gene therapy. We have developed a gene transfection method, based on light-inducible photochemical internalization (PCI) of a transgene, to improve gene delivery and expression selectively in illuminated areas, for example, in tumors. In the present work, we demonstrate that PCI improved the nonviral vector polyethylenimine (PEI)-mediated transfection of a therapeutic gene, the 'suicide' gene encoding herpes simplex virus thymidine kinase (HSVtk). In U87MG glioblastoma cells in vitro, the photochemical treatment stimulated expression of the HSVtk transgene, and, consequently, enhanced cell killing by the subsequent treatment with the prodrug ganciclovir (GCV). When relatively low doses of DNA (1 microg/ml) and the PEI vector (N/P 4) were used, HSVtk gene transfection followed by the GCV treatment did not have an effect on cell survival unless the photochemical treatment was performed, which potentiated the cytotoxicity to 90%. These findings indicate that photochemical transfection allows: (i) selective enhancement in gene expression and gene-mediated biological effects (cell killing by the Hsvtk/GCV approach) in response to illumination; (ii) the use of low, suboptimal for the nonviral transfection methods without PCI, doses of both DNA and the vector, which may be relevant and advantageous for therapeutic gene transfer in vivo.
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Affiliation(s)
- Lina Prasmickaite
- Department of Biophysics, Institute for Cancer Research, The Norwegian Radium Hospital, Montebello, N-0310 Oslo, Norway.
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29
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Dietz GPH, Bähr M. Delivery of bioactive molecules into the cell: the Trojan horse approach. Mol Cell Neurosci 2005; 27:85-131. [PMID: 15485768 DOI: 10.1016/j.mcn.2004.03.005] [Citation(s) in RCA: 358] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2003] [Revised: 02/17/2004] [Accepted: 03/16/2004] [Indexed: 01/12/2023] Open
Abstract
In recent years, vast amounts of data on the mechanisms of neural de- and regeneration have accumulated. However, only in disproportionally few cases has this led to efficient therapies for human patients. Part of the problem is to deliver cell death-averting genes or gene products across the blood-brain barrier (BBB) and cellular membranes. The discovery of Antennapedia (Antp)-mediated transduction of heterologous proteins into cells in 1992 and other "Trojan horse peptides" raised hopes that often-frustrating attempts to deliver proteins would now be history. The demonstration that proteins fused to the Tat protein transduction domain (PTD) are capable of crossing the BBB may revolutionize molecular research and neurobiological therapy. However, it was only recently that PTD-mediated delivery of proteins with therapeutic potential has been achieved in models of neural degeneration in nerve trauma and ischemia. Several groups have published the first positive results using protein transduction domains for the delivery of therapeutic proteins in relevant animal models of human neurological disorders. Here, we give an extensive review of peptide-mediated protein transduction from its early beginnings to new advances, discuss their application, with particular focus on a critical evaluation of the limitations of the method, as well as alternative approaches. Besides applications in neurobiology, a large number of reports using PTD in other systems are included as well. Because each protein requires an individual purification scheme that yields sufficient quantities of soluble, transducible material, the neurobiologist will benefit from the experiences of other researchers in the growing field of protein transduction.
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30
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Qiu Z, Zhu J, Harms JS, Friedrichsen J, Splitter GA. Bovine Herpesvirus VP22 Induces Apoptosis in Neuroblastoma Cells by Upregulating the Expression Ratio of Bax to Bcl-2. Hum Gene Ther 2005; 16:101-8. [PMID: 15703493 DOI: 10.1089/hum.2005.16.101] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Herpesvirus tegument protein VP22 has been shown to have biotherapeutic potential in tumor gene therapy. Some studies indicate that VP22 may enhance the transfer efficiency of therapeutic proteins by delivering them to more cells while trafficking. Our previous study showed that bovine herpesvirus VP22 (BVP22) enhanced equine herpesvirus thymidine kinase-ganciclovir (Etk-GCV) suicide gene therapy by an unknown intracellular effect. In this study, the interaction between BVP22 and host tumor cells was studied in neuroblastoma NXS2 cells. Cell cycle analysis was performed to determine whether BVP22 possesses biotherapeutic potential by altering the cell cycle, making cells more sensitive to therapeutic genes. As a result, the cell cycle was not affected by the transfection of BVP22 into NXS2 cells. However, cytotoxicity induced by BVP22 was observed in NXS2 cells on the second and third days after transient transfection. Further, analyses of caspase-3 activity and apoptosis suggested that BVP22 induces apoptosis in host tumor cells by upregulating the expression ratio of Bax to Bcl-2.
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Affiliation(s)
- Zhaohua Qiu
- Department of Animal Health and Biomedical Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA
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31
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Sheridan PJ, Lawrie A, Crossman DC, Holt CM, Newman CM. VP22-mediated intercellular transport correlates with enhanced biological activity of MybEngrailed but not (HSV-I) thymidine kinase fusion proteins in primary vascular cells following non-viral transfection. J Gene Med 2005; 7:375-85. [PMID: 15543525 DOI: 10.1002/jgm.679] [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: 11/11/2022] Open
Abstract
BACKGROUND The intercellular transport properties of the herpes simplex virus (HSV) protein VP22 have been harnessed to enhance the effectiveness of viral gene transfer. We investigated the intercellular transport and biological effects of VP22 fused with the dominant negative c-Myb chimera, MybEngrailed (MybEn) and HSV-I thymidine kinase (TK), in primary vascular smooth muscle cells (VSMC) following non-viral transfection. MATERIALS AND METHODS Porcine VSMC transfected with plasmids encoding MybEn, TK and their respective N- and C-terminal VP22 fusion proteins were assayed for the extent and distribution of transgene expression (by immunohistochemistry), culture growth and apoptosis. RESULTS The N-terminal MybEn fusion with VP22 (MybEnVP22) and both TK fusions, but not VP22MybEn, exhibited intercellular spread from primary transfected to up to 200 surrounding cells. pMybEnVP22-transfected cultures exhibited growth inhibition and apoptosis rates that were 10.6 +/- 3.6 and 3.2 +/- 1.0 fold higher than in pMybEn-transfected cultures; pVP22MybEn-transfected cultures showed no difference in these parameters. pTK-transfected cultures underwent 60-70% cell death in the presence of ganciclovir despite <2% primary transfection, which was not increased in cultures transfected with plasmids encoding VP22-TK fusions. CONCLUSIONS The close correlation between immunocytochemical and biological assays suggests that intercellular transport is crucial to the enhanced biological activity of the MybEnVP22 fusion. The "intrinsic" bystander activity of TK was 4-fold greater than was "engineered" by VP22 fusion, probably reflecting the abundance of gap junctions between VSMC. VP22 fusion may enhance the efficiency of non-viral gene delivery when combined with the appropriate therapeutic transgene, target tissue and transfection method.
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Affiliation(s)
- Paul J Sheridan
- Cardiovascular Research Unit, Division of Clinical Sciences (North), Clinical Sciences Centre, University of Sheffield, Northern General Hospital, Sheffield S5 7AU, UK.
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32
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Vassaux G, Martin-Duque P. Use of suicide genes for cancer gene therapy: study of the different approaches. Expert Opin Biol Ther 2004; 4:519-30. [PMID: 15102601 DOI: 10.1517/14712598.4.4.519] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Cancer is a disease of high incidence for which conventional treatments are not necessarily effective. There is a need for the development of new alternative strategies. Among them, suicide gene therapy has been developed. In this approach, a gene encoding for a protein toxic under particular conditions is delivered to the target cells, resulting in their death. Although this approach has been in development for a long time, new combinations with other gene therapy areas, such as selective replicative viruses, tumour targeting, or conventional treatments such as chemo- or radiotherapy, are currently being tested. This review will summarise some of these approaches.
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Affiliation(s)
- G Vassaux
- Universidade Francisco de Vitoria, Ctra, Pazuelo de Alarcon, Madrid, Spain.
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Qiu Z, Harms JS, Zhu J, Splitter GA. Bovine herpesvirus tegument protein VP22 enhances thymidine kinase/ganciclovir suicide gene therapy for neuroblastomas compared to herpes simplex virus VP22. J Virol 2004; 78:4224-33. [PMID: 15047837 PMCID: PMC374295 DOI: 10.1128/jvi.78.8.4224-4233.2004] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2003] [Accepted: 12/12/2003] [Indexed: 11/20/2022] Open
Abstract
Herpesvirus tegument protein VP22 can enhance the effect of therapeutic proteins in gene therapy, such as thymidine kinase (tk) and p53; however, the mechanism is unclear or controversial. In this study, mammalian expression vectors carrying bovine herpesvirus 1 (BHV-1) VP22 (BVP22) or herpes simplex virus type 1 (HSV-1) VP22 (HVP22) and equine herpesvirus type 4 (EHV-4) tk (Etk) were constructed in order to evaluate and compare the therapeutic potentials of BVP22 and HVP22 to enhance Etk/ganciclovir (Etk/GCV) suicide gene therapy for neuroblastomas by GCV cytotoxicity assays and noninvasive bioluminescent imaging in vitro and in vivo. BVP22 enhanced Etk/GCV cytotoxicity compared to that with HVP22 both in vitro and in vivo. However, assays utilizing a mixture of parental and stably transfected cells indicated that the enhancement was detected only in transfected cells. Thus, the therapeutic potential of BVP22 and HVP22 in Etk/GCV suicide gene therapy in this tumor system is not due to VP22 delivery of Etk into surrounding cells but rather is likely due to an enhanced intracellular effect.
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Affiliation(s)
- Zhaohua Qiu
- Department of Animal Health and Biomedical Sciences, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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Affiliation(s)
- Friedrich C Luft
- Franz-Volhard-Klinik, Humboldt University of Berlin, Wiltbergstrasse 50, 13125, Berlin-Buch, Germany.
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Dancer A, Julien S, Bouillot S, Pointu H, Vernet M, Huber P. Expression of thymidine kinase driven by an endothelial-specific promoter inhibits tumor growth of Lewis lung carcinoma cells in transgenic mice. Gene Ther 2003; 10:1170-8. [PMID: 12833126 DOI: 10.1038/sj.gt.3301981] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The possibility of inhibiting tumor growth by limiting angiogenesis has raised considerable interest. In this study, we examined the feasibility of inhibiting tumor growth by targeting a suicide gene in the endothelium. Toxicity must be directed solely to angiogenic cells. Therefore, we used the herpes simplex virus-thymidine kinase (TK) gene, in combination with the prodrug ganciclovir (GCV), which affects replicative cells. To test this strategy, we produced transgenic mice carrying the TK gene driven by the vascular endothelial (VE)-cadherin promoter. Lewis lung carcinoma cells were injected subcutaneously to establish tumors and to test the effect of GCV on tumor growth. In two independent transgenic lines, GCV treatment (75 mg/kg/day) resulted in a 66-71% reduction of tumor volume at day 20 postimplantation compared to wild-type mice (650 and 550 versus 1930 mm(3), P<0.02 and 0.01, respectively), whereas no significant difference was observed when vehicle alone was injected. Tumor growth inhibition was accompanied by a marked reduction in tumor vascular density (151 versus 276 vessels/mm(2), P<0.05) and an increase in tumor cell death, suggesting that tumor growth inhibition was caused by a reduction in tumor angiogenesis. Our data support the potential utility of endothelial targeting of suicide genes in cancer therapy.
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Affiliation(s)
- A Dancer
- CEA, Laboratoire de Dévelopement et Vieillissement de l'Endothélium, INSERM EMI 02-19, France
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Wagner S, Chiosea S, Nickerson JA. The spatial targeting and nuclear matrix binding domains of SRm160. Proc Natl Acad Sci U S A 2003; 100:3269-74. [PMID: 12624182 PMCID: PMC152281 DOI: 10.1073/pnas.0438055100] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The Ser-Arg (SR)-related protein SRm160 is a coactivator of pre-mRNA splicing. It bridges splicing factors located at the 5' splice site, branch site, and 3' splice site. Recently, SRm160 has also been shown to be involved in mRNA export as part of an exon-junction complex. SRm160 is highly concentrated in splicing speckles but is also present in long branched intranuclear tracks connecting splicing speckles with sites at the nuclear lamina. In this study we identified domains of SRm160 important for spatial targeting within the nucleus and for binding to the nuclear matrix. Using a series of FLAG- and enhanced GFP-conjugated deletion mutants we found two contiguous sequences that independently target SRm160 to nuclear matrix sites at splicing speckled domains: amino acids 300-350 and 351-688. Constructs containing amino acids 300-350 were also targeted to sites peripheral to speckled domains where most mRNA originate subsequent to splicing. Sequences from the N-terminal domain localized proteins to the nuclear lamina near sites where mRNA leaves the nucleus.
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Affiliation(s)
- Stefan Wagner
- Department of Cell Biology, University of Massachusetts Medical School, 55 Lake Avenue, Worcester, MA 01655, USA
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37
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Zavaglia D, Favrot MC, Eymin B, Tenaud C, Coll JL. Intercellular trafficking and enhanced in vivo antitumour activity of a non-virally delivered P27-VP22 fusion protein. Gene Ther 2003; 10:314-25. [PMID: 12595890 DOI: 10.1038/sj.gt.3301904] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
VP22, a structural protein from herpes simplex virus type I, exhibits the unique property of intercellular trafficking. This protein is exported from primary expressing cells and subsequently imported into neighbouring cells. This property is conserved when VP22 is genetically fused to a protein, making it a promising tool to enhance the delivery of a gene product. We chose to study the intercellular transport and biological effect of a fusion protein between the putative tumour suppressor gene p27(Kip1) and VP22. We show that in vitro, P27VP22 is able to spread as efficiently as VP22. Functionality of the P27VP22 protein was demonstrated by its ability to inhibit cyclin/CDK2 complexes activity. In proliferation and clonogenicity assays, transfection with the P27VP22 plasmid resulted in a stronger cell growth inhibition when compared to transfection with the p27(Kip1) vector. In vivo, sub cutaneous tumours established in nude mice were injected with naked DNA encoding P27 or P27VP22. Our results show that P27VP22 can spread in vivo and that injections of the P27VP22 plasmid resulted in a significantly greater antitumour activity than injections of the P27 plasmid. This study confirms the usefulness of VP22-mediated delivery and suggests that P27VP22 may have applications in cancer gene therapy.
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Affiliation(s)
- D Zavaglia
- Groupe de Recherche sur le Cancer du Pumon, Equipe INSERM 9924, Institut Albert Bonnoit, La Tronche cedex, France
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38
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Tasciotti E, Zoppè M, Giacca M. Transcellular transfer of active HSV-1 thymidine kinase mediated by an 11-amino-acid peptide from HIV-1 Tat. Cancer Gene Ther 2003; 10:64-74. [PMID: 12489030 DOI: 10.1038/sj.cgt.7700526] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2002] [Indexed: 11/08/2022]
Abstract
Suicide gene therapy using herpes simplex virus type-1 (HSV-1) thymidine kinase (TK) is a widely exploited approach for gene therapy of cancer and other hyperproliferative disorders. Despite its popularity, clinical success has been so far hampered mostly by the relative inefficiency of TK gene transfer and its limited bystander effect. Here we report that fusion of TK to an 11-amino-acid peptide from the basic domain of the HIV-1 Tat protein (Tat11) imparts cell membrane translocating ability to the enzyme and significantly increases its cytotoxic efficacy. In cells expressing Tat11-TK, this protein is found extracellularly, associated with cell surface heparan sulfate proteoglycans, and is released into the cell culture medium. Based on its interaction with HSPGs, the protein is then internalized by neighboring, nonexpressing cells, which become susceptible to cell death when treated with the nucleoside analogue acyclovir. As a consequence, co-cultures of wild-type cells with cells expressing Tat11-TK show increased sensitivity to ACV through a mechanism involving apoptosis. Modification of TK by fusion with Tat11 might constitute an important step for the optimization of TK suicide gene strategy for gene therapy of cellular proliferation.
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Affiliation(s)
- Ennio Tasciotti
- Molecular Medicine Laboratory, International Center for Genetic Engineering and Biotechnology (ICGEB), Trieste, Italy
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Cashman SM, Sadowski SL, Morris DJ, Frederick J, Kumar-Singh R. Intercellular trafficking of adenovirus-delivered HSV VP22 from the retinal pigment epithelium to the photoreceptors--implications for gene therapy. Mol Ther 2002; 6:813-23. [PMID: 12498777 DOI: 10.1006/mthe.2002.0806] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Adenovirus (Ad)-mediated gene transfer is a promising technology for therapy of a wide variety of genetic disorders of the retina. The tropism of Ad vectors limits their utility to cells that express the coxsackie-adenovirus receptor. Upon ocular delivery, Ad vectors primarily infect the retinal pigment epithelium (RPE) and the Müller cells of the retina. However, the most frequent blinding diseases such as retinitis pigmentosa and age-related macular degeneration are associated with the expression of mutant proteins in the photoreceptors. In this study we demonstrate that adenovirus-delivered heterologous proteins fused to the herpes simplex virus tegument protein VP22 can translocate from infected cells to uninfected cells in culture and in vivo. We tested three different ocular cell lines, specifically Y79, RPE-J, and Chang C. We show that there is a 3.25-fold increase in the number of Y79 cells that take up GFP mediated by the intercellular trafficking properties of VP22. Our data are based on FACS analysis of living cells and there was no need for cell fixation for the effect to be observed. When adenovirus expressing a VP22-GFP fusion was injected into the subretinal space of adult mice, the VP22-GFP fusion peptides translocated from the RPE to all of the other layers of the retina, including the outer nuclear layer, which contains the photoreceptor cell bodies. Our study has significant implications for a wide variety of diseases of the retina and other organ systems.
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Affiliation(s)
- Siobhan M Cashman
- Department of Ophthalmology, University of Utah, Salt Lake City, Utah 84112-5330, USA
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Abstract
Tissue regeneration in humans is limited and excludes vitals organs like heart and brain. Transformation experiments with oncogenes like T antigen have shown that retrodifferentiation of the respective cells is possible but hard to control. To bypass the risk of cancer formation a protein therapy approach has been developed. The transient delivery of proteins rather than genes could still induce terminally-differentiated cells to reenter the cell cycle. This approach takes advantage of protein-transducing domains that mediate the transfer of cargo proteins into cells. The goal of this brief review is to outline the basics of protein transduction and to discuss potential applications for tissue regeneration.
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Zender L, Köck R, Eckhard M, Frericks B, Gösling T, Gebhardt T, Drobek S, Galanski M, Kühnel F, Manns M, Kubicka S. Gene therapy by intrahepatic and intratumoral trafficking of p53-VP22 induces regression of liver tumors. Gastroenterology 2002; 123:608-18. [PMID: 12145813 DOI: 10.1053/gast.2002.34756] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS VP22-mediated intercellular transport provides an approach to deliver functional chimeric proteins into a high percentage of target cells. The aim of this study was to evaluate the efficacy of p53/VP22 fusion protein in gene therapy of liver tumors. METHODS Expression vectors of N- and C-terminal fusion proteins of p53 and VP22 were subcloned and transcriptional properties of chimeric proteins were assessed by luciferase assays. Adenoviral vectors expressing p53 wild type (AdGFP/p53wt) and p53-VP22 (AdGFP/p53-VP22) were generated to investigate the VP22-mediated spreading in normal liver and in liver tumors in vivo by green fluorescent protein fluorescence and p53 immunohistochemistry. Gene therapy was investigated in subcutaneous and preclinical orthotopic animal tumor models after subcutaneous and intra-arterial administration of the adenoviruses, and tumor growth was assessed by direct calibration and magnetic resonance imaging. RESULTS p53-VP22 showed enhanced transcriptional activity compared with p53 wild type. VP22-mediated intercellular transport of p53 could be observed in the normal liver and in liver tumors in vivo and was correlated with increased antitumor efficacy of gene therapy and improved survival of the animals. CONCLUSIONS Fusion of VP22 to p53 strongly improves the results of p53 replacement gene therapy. Furthermore, the demonstrated VP22-mediated intercellular transport in the liver could be important for other strategies in liver gene therapy, providing a tool for enhancing the effect of gene therapy in liver diseases such as metabolic disorders or viral hepatitis.
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Affiliation(s)
- Lars Zender
- Department of Gastroenterology and Hepatology, Medical School Hannover, Hannover, Germany
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Zender L, Kühnel F, Köck R, Manns M, Kubicka S. VP22-mediated intercellular transport of p53 in hepatoma cells in vitro and in vivo. Cancer Gene Ther 2002; 9:489-96. [PMID: 12032659 DOI: 10.1038/sj.cgt.7700465] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2002] [Indexed: 12/13/2022]
Abstract
The capacity of VP22 chimeric proteins to spread from the primary transduced cell to surrounding cells could improve gene therapy approaches, especially in cancer therapy. However, there are conflicting data about VP22-mediated intercellular trafficking in different studies. To assess the role of VP22 in gene therapy of hepatocellular carcinomas (HCCs) we constructed expression vectors for N- and C-terminal versions of VP22-p53 fusion proteins and investigated the VP22-mediated shuttle effect in hepatoma cells by cotransfection experiments. VP22-mediated trafficking was not detectable in hepatoma cells in vitro by fluorescence microscopy, but reporter gene transactivation assays demonstrated intercellular trafficking of functional VP22-p53 in vitro. For in vivo experiments, the recombinant adenoviruses Ad5CMVp53 and Ad5CMVp53-VP22 were constructed. In contrast to the in vitro experiments intercellular trafficking of VP22-p53 could be observed in subcutaneous tumors of hepatoma cells by fluorescence microscopy, indicating a stronger shuttle effect in solid tumors compared to cell culture experiments. Because spread of p53-VP22 in liver tumors was correlated with enhanced apoptosis of hepatoma cells VP22-mediated trafficking of potential therapeutic proteins may improve the results of gene therapy of HCCs.
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Affiliation(s)
- Lars Zender
- Department of Gastroenterology and Hepatology, Medical School Hannover, Hannover 30625, Germany
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