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Cooney AL, Loza LM, Najdawi K, Brommel CM, McCray PB, Sinn PL. High ionic strength vector formulations enhance gene transfer to airway epithelia. Nucleic Acids Res 2024; 52:9369-9383. [PMID: 39077931 PMCID: PMC11381324 DOI: 10.1093/nar/gkae640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 06/24/2024] [Accepted: 07/09/2024] [Indexed: 07/31/2024] Open
Abstract
A fundamental challenge for cystic fibrosis (CF) gene therapy is ensuring sufficient transduction of airway epithelia to achieve therapeutic correction. Hypertonic saline (HTS) is frequently administered to people with CF to enhance mucus clearance. HTS transiently disrupts epithelial cell tight junctions, but its ability to improve gene transfer has not been investigated. Here, we asked if increasing the concentration of NaCl enhances the transduction efficiency of three gene therapy vectors: adenovirus, AAV, and lentiviral vectors. Vectors formulated with 3-7% NaCl exhibited markedly increased transduction for all three platforms, leading to anion channel correction in primary cultures of human CF epithelial cells and enhanced gene transfer in mouse and pig airways in vivo. The mechanism of transduction enhancement involved tonicity but not osmolarity or pH. Formulating vectors with a high ionic strength solution is a simple strategy to greatly enhance efficacy and immediately improve preclinical or clinical applications.
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Affiliation(s)
- Ashley L Cooney
- University of Iowa, Stead Family Department of Pediatrics; Iowa City, IA 52242, USA
- University of Iowa, Pappajohn Biomedical Institute; Iowa City, IA 52242, USA
| | - Laura Marquez Loza
- University of Iowa, Stead Family Department of Pediatrics; Iowa City, IA 52242, USA
- University of Iowa, Pappajohn Biomedical Institute; Iowa City, IA 52242, USA
| | - Kenan Najdawi
- University of Iowa, Stead Family Department of Pediatrics; Iowa City, IA 52242, USA
- University of Iowa, Pappajohn Biomedical Institute; Iowa City, IA 52242, USA
| | - Christian M Brommel
- University of Iowa, Stead Family Department of Pediatrics; Iowa City, IA 52242, USA
- University of Iowa, Pappajohn Biomedical Institute; Iowa City, IA 52242, USA
| | - Paul B McCray
- University of Iowa, Stead Family Department of Pediatrics; Iowa City, IA 52242, USA
- University of Iowa, Pappajohn Biomedical Institute; Iowa City, IA 52242, USA
- University of Iowa, Center for Gene Therapy; Iowa City, IA 52242, USA
| | - Patrick L Sinn
- University of Iowa, Stead Family Department of Pediatrics; Iowa City, IA 52242, USA
- University of Iowa, Pappajohn Biomedical Institute; Iowa City, IA 52242, USA
- University of Iowa, Center for Gene Therapy; Iowa City, IA 52242, USA
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Cooney AL, Loza LM, Najdawi K, Brommel CM, McCray PB, Sinn PL. High ionic strength vector formulations enhance gene transfer to airway epithelia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.22.576687. [PMID: 38328187 PMCID: PMC10849541 DOI: 10.1101/2024.01.22.576687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2024]
Abstract
A fundamental challenge for cystic fibrosis (CF) gene therapy is ensuring sufficient transduction of airway epithelia to achieve therapeutic correction. Hypertonic saline (HTS) is frequently administered to people with CF to enhance mucus clearance. HTS transiently disrupts epithelial cell tight junctions, but its ability to improve gene transfer has not been investigated. Here we asked if increasing the concentration of NaCl enhances the transduction efficiency of three gene therapy vectors: adenovirus, AAV, and lentiviral vectors. Vectors formulated with 3-7% NaCl exhibited markedly increased transduction for all three platforms, leading to anion channel correction in primary cultures of human CF epithelial cells and enhanced gene transfer in mouse and pig airways in vivo. The mechanism of transduction enhancement involved tonicity but not osmolarity or pH. Formulating vectors with a high ionic strength solution is a simple strategy to greatly enhance efficacy and immediately improve preclinical or clinical applications.
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Affiliation(s)
- Ashley L. Cooney
- University of Iowa, Department of Pediatrics; Iowa City, IA 52242, USA
- University of Iowa, Center for Cystic Fibrosis Gene Therapy; Iowa City, IA 52242, USA
| | - Laura Marquez Loza
- University of Iowa, Department of Pediatrics; Iowa City, IA 52242, USA
- University of Iowa, Center for Cystic Fibrosis Gene Therapy; Iowa City, IA 52242, USA
| | - Kenan Najdawi
- University of Iowa, Department of Pediatrics; Iowa City, IA 52242, USA
- University of Iowa, Center for Cystic Fibrosis Gene Therapy; Iowa City, IA 52242, USA
| | - Christian M. Brommel
- University of Iowa, Department of Pediatrics; Iowa City, IA 52242, USA
- University of Iowa, Center for Cystic Fibrosis Gene Therapy; Iowa City, IA 52242, USA
| | - Paul B. McCray
- University of Iowa, Department of Pediatrics; Iowa City, IA 52242, USA
- University of Iowa, Center for Cystic Fibrosis Gene Therapy; Iowa City, IA 52242, USA
- University of Iowa, Department of Microbiology and Immunology, Iowa City, IA 52242, USA
| | - Patrick L. Sinn
- University of Iowa, Department of Pediatrics; Iowa City, IA 52242, USA
- University of Iowa, Center for Cystic Fibrosis Gene Therapy; Iowa City, IA 52242, USA
- University of Iowa, Department of Microbiology and Immunology, Iowa City, IA 52242, USA
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Maeda N, Inoshima Y, De Las Heras M, Maenaka K. Enzootic nasal tumor virus type 2 envelope of goats acts as a retroviral oncogene in cell transformation. Virus Genes 2020; 57:50-59. [PMID: 33151445 DOI: 10.1007/s11262-020-01808-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 10/30/2020] [Indexed: 11/26/2022]
Abstract
Enzootic nasal tumor virus type 1 (ENTV-1) (ovine nasal tumor virus) and ENTV-2 (caprine nasal tumor virus) are known to be causative agents of enzootic nasal adenocarcinoma (ENA) in sheep and goats, respectively. Although the nucleotide and amino acid sequences of ENTV-1 and ENTV-2 are quite similar, they are recognized as phylogenetically distinct viruses. The envelope protein of ENTV-1 functions as an oncoprotein in the in vitro transformation of epithelial cells and fibroblasts. Thus, it is the primary determinant of in vivo tumorigenesis in ENA. As per our knowledge, no previous studies have reported in detail the role of ENTV-2 in ENA tumorigenesis. Here, in order to investigate the molecular mechanism of caprine ENA oncogenesis by ENTV-2, we have attempted to identify the transforming potential of ENTV-2 envelope, and investigated the activation of cell signaling pathways in oncogenic transformation. Our findings confirmed that ENTV-2 envelope was capable of inducing oncogenic transformation of rat cell lines in vitro. Further, we found that MAPK, Akt, and p38 were constitutively activated in ENTV-2 envelope-transformed clone cells. In addition, inhibitor experiments revealed that MEK-MAPK and PI3K-Akt signaling pathways are involved in the ENTV-2 envelope-induced cell transformation. These data indicate that ENTV-2 envelope could induce oncogenic transformation by signaling pathways that are also utilized by ENTV-1 envelope.
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Affiliation(s)
- Naoyoshi Maeda
- Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo, 060-0812, Japan.
| | - Yasuo Inoshima
- Laboratory of Food and Environmental Hygiene, Cooperative Department of Veterinary Medicine, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan
| | | | - Katsumi Maenaka
- Center for Research and Education on Drug Discovery, Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo, 060-0812, Japan
- Laboratory of Biomolecular Science, Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo, 060-0812, Japan
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4
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Cooney AL, McCray PB, Sinn PL. Cystic Fibrosis Gene Therapy: Looking Back, Looking Forward. Genes (Basel) 2018; 9:genes9110538. [PMID: 30405068 PMCID: PMC6266271 DOI: 10.3390/genes9110538] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 10/30/2018] [Accepted: 10/31/2018] [Indexed: 01/02/2023] Open
Abstract
Cystic fibrosis (CF) is an autosomal recessive disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene that encodes a cAMP-regulated anion channel. Although CF is a multi-organ system disease, most people with CF die of progressive lung disease that begins early in childhood and is characterized by chronic bacterial infection and inflammation. Nearly 90% of people with CF have at least one copy of the ΔF508 mutation, but there are hundreds of CFTR mutations that result in a range of disease severities. A CFTR gene replacement approach would be efficacious regardless of the disease-causing mutation. After the discovery of the CFTR gene in 1989, the in vitro proof-of-concept for gene therapy for CF was quickly established in 1990. In 1993, the first of many gene therapy clinical trials attempted to rescue the CF defect in airway epithelia. Despite the initial enthusiasm, there is still no FDA-approved gene therapy for CF. Here we discuss the history of CF gene therapy, from the discovery of the CFTR gene to current state-of-the-art gene delivery vector designs. While implementation of CF gene therapy has proven more challenging than initially envisioned; thanks to continued innovation, it may yet become a reality.
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Affiliation(s)
- Ashley L Cooney
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.
| | - Paul B McCray
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.
| | - Patrick L Sinn
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.
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5
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Walsh SR, de Jong JG, van Vloten JP, Gerpe MCR, Santry LA, Wootton SK. Truncation of the enzootic nasal tumor virus envelope protein cytoplasmic tail increases Env-mediated fusion and infectivity. J Gen Virol 2017; 98:108-120. [PMID: 27902399 DOI: 10.1099/jgv.0.000654] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Enzootic nasal tumor virus (ENTV) and Jaagsiekte sheep retrovirus (JSRV) are highly related ovine betaretroviruses that induce nasal and lung tumours in small ruminants, respectively. While the ENTV and JSRV envelope (Env) glycoproteins mediate virus entry using the same cellular receptor, the glycosylphosphatidylinositol-linked protein hyaluronoglucosaminidase, ENTV Env pseudovirions mediate entry into cells from a much more restricted range of species than do JSRV Env pseudovirions. Unlike JSRV Env, ENTV Env does not induce cell fusion at pH 5.0 or above, but rather requires a much lower pH (4.0-4.5) for fusion to occur. The cytoplasmic tail of retroviral envelope proteins is a key modulator of envelope-mediated fusion and pseudotype efficiency, especially in the context of virions composed of heterologous Gag proteins. Here we report that progressive truncation of the ENTV Env cytoplasmic tail improves transduction efficiency of pseudotyped retroviral vectors and that complete truncation of the ENTV Env cytoplasmic tail increases transduction efficiency to wild-type JSRV Env levels by increasing fusogenicity without affecting sensitivity to inhibition by lysosomotropic agents, subcellular localization or efficiency of inclusion into virions. Truncation of the cytoplasmic domain of ENTV Env resulted in a significant advantage in viral entry into all cell types tested, including foetal ovine lung and nasal cells. Taken together, we demonstrate that the cytoplasmic tail modulates the fusion activity of the ENTV Env protein and that truncation of this region enhances Eenv-mediated entry into target cells.
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Affiliation(s)
- Scott R Walsh
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada
| | - Jondavid G de Jong
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada
| | - Jacob P van Vloten
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada
| | | | - Lisa A Santry
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada
| | - Sarah K Wootton
- Present address: McMaster Immunology Research Centre, McMaster University, Hamilton, ON, Canada.,Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada
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Miller AD, De las Heras M, Yu J, Zhang F, Liu SL, Vaughan AE, Vaughan TL, Rosadio R, Rocca S, Palmieri G, Goedert JJ, Fujimoto J, Wistuba II. Evidence against a role for jaagsiekte sheep retrovirus in human lung cancer. Retrovirology 2017; 14:3. [PMID: 28107820 PMCID: PMC5248497 DOI: 10.1186/s12977-017-0329-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 12/22/2016] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Jaagsiekte sheep retrovirus (JSRV) causes a contagious lung cancer in sheep and goats that can be transmitted by aerosols produced by infected animals. Virus entry into cells is initiated by binding of the viral envelope (Env) protein to a specific cell-surface receptor, Hyal2. Unlike almost all other retroviruses, the JSRV Env protein is also a potent oncoprotein and is responsible for lung cancer in animals. Of concern, Hyal2 is a functional receptor for JSRV in humans. RESULTS We show here that JSRV is fully capable of infecting human cells, as measured by its reverse transcription and persistence in the DNA of cultured human cells. Several studies have indicated a role for JSRV in human lung cancer while other studies dispute these results. To further investigate the role of JSRV in human lung cancer, we used highly-specific mouse monoclonal antibodies and a rabbit polyclonal antiserum against JSRV Env to test for JSRV expression in human lung cancer. JSRV Env expression was undetectable in lung cancers from 128 human subjects, including 73 cases of bronchioalveolar carcinoma (BAC; currently reclassified as lung invasive adenocarcinoma with a predominant lepidic component), a lung cancer with histology similar to that found in JSRV-infected sheep. The BAC samples included 8 JSRV DNA-positive samples from subjects residing in Sardinia, Italy, where sheep farming is prevalent and JSRV is present. We also tested for neutralizing antibodies in sera from 138 Peruvians living in an area where sheep farming is prevalent and JSRV is present, 24 of whom were directly exposed to sheep, and found none. CONCLUSIONS We conclude that while JSRV can infect human cells, JSRV plays little if any role in human lung cancer.
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Affiliation(s)
- A. Dusty Miller
- Fred Hutchinson Cancer Research Center, Seattle, WA USA
- Department of Pathology, University of Washington, Seattle, WA USA
- 17915 Edmundson Rd, Sisters, OR 97759 USA
| | | | - Jingyou Yu
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, OH USA
- Department of Molecular Microbiology and Immunology, Bond Life Sciences Canter, University of Missouri, Columbia, MO USA
| | - Fushun Zhang
- Department of Molecular Microbiology and Immunology, Bond Life Sciences Canter, University of Missouri, Columbia, MO USA
| | - Shan-Lu Liu
- Center for Retrovirus Research, Department of Veterinary Biosciences, The Ohio State University, Columbus, OH USA
- Department of Molecular Microbiology and Immunology, Bond Life Sciences Canter, University of Missouri, Columbia, MO USA
| | - Andrew E. Vaughan
- Fred Hutchinson Cancer Research Center, Seattle, WA USA
- Department of Medicine, University of California San Francisco, San Francisco, CA USA
| | - Thomas L. Vaughan
- Program in Epidemiology, Fred Hutchinson Cancer Research Center, Seattle, WA USA
| | - Raul Rosadio
- Veterinary Faculty, National University of San Marcos, Lima, Peru
| | - Stefano Rocca
- Department of Veterinary Medicine, Sassari University, Sassari, Italy
| | - Giuseppe Palmieri
- Unit of Cancer Genetics, Institute of Biomolecular Chemistry, National Research Council, Sassari, Italy
| | - James J. Goedert
- Division of Cancer Epidemiology and Genetics, National Cancer Institute, Rockville, MD USA
| | - Junya Fujimoto
- Department of Translational Molecular Pathology, University of Texas MD Anderson Cancer Center, Houston, TX USA
| | - Ignacio I. Wistuba
- Department of Translational Molecular Pathology, University of Texas MD Anderson Cancer Center, Houston, TX USA
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Youssef G, Wallace WAH, Dagleish MP, Cousens C, Griffiths DJ. Ovine pulmonary adenocarcinoma: a large animal model for human lung cancer. ILAR J 2016; 56:99-115. [PMID: 25991702 DOI: 10.1093/ilar/ilv014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Lung cancer is the leading cause of cancer deaths worldwide. Recent progress in understanding the molecular pathogenesis of this disease has resulted in novel therapeutic strategies targeting specific groups of patients. Further studies are required to provide additional advances in diagnosis and treatment. Animal models are valuable tools for studying oncogenesis in lung cancer, particularly during the early stages of disease where tissues are rarely available from human cases. Mice have traditionally been used for studying lung cancer in vivo, and a variety of spontaneous and transgenic models are available. However, it is recognized that other species may also be informative for studies of cancer. Ovine pulmonary adenocarcinoma (OPA) is a naturally occurring lung cancer of sheep caused by retrovirus infection and has several features in common with adenocarcinoma of humans, including a similar histological appearance and activation of common cell signaling pathways. Additionally, the size and organization of human lungs are much closer to those of sheep lungs than to those of mice, which facilitates experimental approaches in sheep that are not available in mice. Thus OPA presents opportunities for studying lung tumor development that can complement conventional murine models. Here we describe the potential applications of OPA as a model for human lung adenocarcinoma with an emphasis on the various in vivo and in vitro experimental systems available.
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Affiliation(s)
- Gehad Youssef
- Gehad Youssef, BSc, is a research scientist at the Moredun Research Institute, Edinburgh, UK. William A. H. Wallace, MBChB(Hons), PhD, FRCPE, FRCPath, is a consultant pathologist at the Royal Infirmary of Edinburgh and Honorary Reader in Pathology, Edinburgh University, UK; Mark P. Dagleish BVM&S, PhD, MRCVS, FRCPath, is Head of Pathology at the Moredun Research Institute, Edinburgh, UK. Chris Cousens, PhD, is a senior research scientist at the Moredun Research Institute, Edinburgh, UK, and David J. Griffiths, PhD, is a principal research scientist at the Moredun Research Institute, Edinburgh, UK
| | - William A H Wallace
- Gehad Youssef, BSc, is a research scientist at the Moredun Research Institute, Edinburgh, UK. William A. H. Wallace, MBChB(Hons), PhD, FRCPE, FRCPath, is a consultant pathologist at the Royal Infirmary of Edinburgh and Honorary Reader in Pathology, Edinburgh University, UK; Mark P. Dagleish BVM&S, PhD, MRCVS, FRCPath, is Head of Pathology at the Moredun Research Institute, Edinburgh, UK. Chris Cousens, PhD, is a senior research scientist at the Moredun Research Institute, Edinburgh, UK, and David J. Griffiths, PhD, is a principal research scientist at the Moredun Research Institute, Edinburgh, UK
| | - Mark P Dagleish
- Gehad Youssef, BSc, is a research scientist at the Moredun Research Institute, Edinburgh, UK. William A. H. Wallace, MBChB(Hons), PhD, FRCPE, FRCPath, is a consultant pathologist at the Royal Infirmary of Edinburgh and Honorary Reader in Pathology, Edinburgh University, UK; Mark P. Dagleish BVM&S, PhD, MRCVS, FRCPath, is Head of Pathology at the Moredun Research Institute, Edinburgh, UK. Chris Cousens, PhD, is a senior research scientist at the Moredun Research Institute, Edinburgh, UK, and David J. Griffiths, PhD, is a principal research scientist at the Moredun Research Institute, Edinburgh, UK
| | - Chris Cousens
- Gehad Youssef, BSc, is a research scientist at the Moredun Research Institute, Edinburgh, UK. William A. H. Wallace, MBChB(Hons), PhD, FRCPE, FRCPath, is a consultant pathologist at the Royal Infirmary of Edinburgh and Honorary Reader in Pathology, Edinburgh University, UK; Mark P. Dagleish BVM&S, PhD, MRCVS, FRCPath, is Head of Pathology at the Moredun Research Institute, Edinburgh, UK. Chris Cousens, PhD, is a senior research scientist at the Moredun Research Institute, Edinburgh, UK, and David J. Griffiths, PhD, is a principal research scientist at the Moredun Research Institute, Edinburgh, UK
| | - David J Griffiths
- Gehad Youssef, BSc, is a research scientist at the Moredun Research Institute, Edinburgh, UK. William A. H. Wallace, MBChB(Hons), PhD, FRCPE, FRCPath, is a consultant pathologist at the Royal Infirmary of Edinburgh and Honorary Reader in Pathology, Edinburgh University, UK; Mark P. Dagleish BVM&S, PhD, MRCVS, FRCPath, is Head of Pathology at the Moredun Research Institute, Edinburgh, UK. Chris Cousens, PhD, is a senior research scientist at the Moredun Research Institute, Edinburgh, UK, and David J. Griffiths, PhD, is a principal research scientist at the Moredun Research Institute, Edinburgh, UK
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8
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Affiliation(s)
- A Dusty Miller
- Fred Hutchinson Cancer Research Center , Seattle, WA 98109
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9
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Monot M, Archer F, Gomes M, Mornex JF, Leroux C. Advances in the study of transmissible respiratory tumours in small ruminants. Vet Microbiol 2015; 181:170-7. [PMID: 26340900 DOI: 10.1016/j.vetmic.2015.08.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Sheep and goats are widely infected by oncogenic retroviruses, namely Jaagsiekte Sheep RetroVirus (JSRV) and Enzootic Nasal Tumour Virus (ENTV). Under field conditions, these viruses induce transformation of differentiated epithelial cells in the lungs for Jaagsiekte Sheep RetroVirus or the nasal cavities for Enzootic Nasal Tumour Virus. As in other vertebrates, a family of endogenous retroviruses named endogenous Jaagsiekte Sheep RetroVirus (enJSRV) and closely related to exogenous Jaagsiekte Sheep RetroVirus is present in domestic and wild small ruminants. Interestingly, Jaagsiekte Sheep RetroVirus and Enzootic Nasal Tumour Virus are able to promote cell transformation, leading to cancer through their envelope glycoproteins. In vitro, it has been demonstrated that the envelope is able to deregulate some of the important signaling pathways that control cell proliferation. The role of the retroviral envelope in cell transformation has attracted considerable attention in the past years, but it appears to be highly dependent of the nature and origin of the cells used. Aside from its health impact in animals, it has been reported for many years that the Jaagsiekte Sheep RetroVirus-induced lung cancer is analogous to a rare, peculiar form of lung adenocarcinoma in humans, namely lepidic pulmonary adenocarcinoma. The implication of a retrovirus related to Jaagsiekte Sheep RetroVirus is still controversial and under investigation, but the identification of an infectious agent associated with the development of lepidic pulmonary adenocarcinomas might help us to understand cancer development. This review explores the mechanisms of induction of respiratory cancers in small ruminants and the possible link between retrovirus and lepidic pulmonary adenocarcinomas in humans.
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Affiliation(s)
- M Monot
- INRA UMR754-Université Lyon 1, Retrovirus and Comparative Pathology, France; Université de Lyon, France
| | - F Archer
- INRA UMR754-Université Lyon 1, Retrovirus and Comparative Pathology, France; Université de Lyon, France
| | - M Gomes
- INRA UMR754-Université Lyon 1, Retrovirus and Comparative Pathology, France; Université de Lyon, France
| | - J-F Mornex
- INRA UMR754-Université Lyon 1, Retrovirus and Comparative Pathology, France; Université de Lyon, France; Hospices Civils de Lyon, France
| | - C Leroux
- INRA UMR754-Université Lyon 1, Retrovirus and Comparative Pathology, France; Université de Lyon, France.
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10
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Jaagsiekte sheep retrovirus detected in human lung cancer tissue arrays. BMC Res Notes 2014; 7:160. [PMID: 24642139 PMCID: PMC3995318 DOI: 10.1186/1756-0500-7-160] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 03/13/2014] [Indexed: 01/15/2023] Open
Abstract
Background Adenocarcinoma is the most common type of non-small cell lung cancer and is frequently observed in non-smoking patients. Adenocarcinoma in-situ (formerly referred to as bronchioloalveolar carcinoma) is a subset of lung adenocarcinoma characterized by growth along alveolar septae without evidence of stromal, vascular, or pleural invasion, that disproportionately affects never-smokers, women, and Asians. Adenocarcinoma in-situ is morphologically and histologically similar to a contagious lung neoplasm of sheep called ovine pulmonary adenocarcinoma (OPA). OPA is caused by infection with the exogenous betaretrovirus, jaagsiekte sheep retrovirus (JSRV), whose envelope protein (Env) is a potent oncogene. Several studies have reported that a proportion of human lung adenocarcinomas are immunopositive for an antigen related to the Gag protein of JSRV, however other groups have been unable to verify these observations by PCR. Methods Here we examine human lung cancer tissue arrays (TA) for evidence of JSRV Env protein and DNA by immunohistochemical staining and PCR, respectively. Results Our results reveal that a subset of human lung cancers express an antigen that reacts with a JSRV Env-specific monoclonal antibody in immunohistochemistry and that exogenous JSRV-like env and gag sequences can be amplified from TA tumor samples, albeit inefficiently. Conclusions While a causative role has not been established, these data suggest that a JSRV-like virus might infect humans. With next generation sequencing approaches, a JSRV-like virus in human lung cancers may be identified which could have profound implications for prevention, diagnosis and therapy.
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Abstract
In this unit, the basic protocol generates stable cell lines that produce retroviral vectors that carry selectable markers. Also included are an alternate protocol that applies when the retroviral vector does not carry a selectable marker, and another alternate protocol for rapidly generating retroviral vector preparations by transient transfection. A support protocol describes construction of the retroviral vectors. The methods for generating virus from retroviral vector plasmids rely on the use of packaging cells that synthesize all of the retroviral proteins but do not produce replication-competent virus. Additional protocols detail plasmid transfection, virus titration, assay for replication-competent virus, and histochemical staining to detect transfer of a vector encoding alkaline phosphatase.
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Affiliation(s)
- A Dusty Miller
- Fred Hutchinson Cancer Research Center and Department of Pathology, University of Washington, Seattle, Washington
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12
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Lutringer-Magnin D, Girard N, Cadranel J, Leroux C, Quoix E, Cottin V, Signore CD, Lebitasy MP, Cordier G, Vanhems P, Mornex JF. Professional exposure to goats increases the risk of pneumonic-type lung adenocarcinoma: results of the IFCT-0504-Epidemio study. PLoS One 2012; 7:e37889. [PMID: 22655078 PMCID: PMC3360000 DOI: 10.1371/journal.pone.0037889] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2012] [Accepted: 04/30/2012] [Indexed: 12/14/2022] Open
Abstract
Pneumonic-type lung adenocarcinoma (P-ADC) represents a distinct subset of lung cancer with specific clinical, radiological, and pathological features. Given the weak association with tobacco-smoking and the striking similarities with jaagsiekte sheep retrovirus (JSRV)-induced ovine pulmonary adenocarcinoma, it has been suggested that a zoonotic viral agent infecting pulmonary cells may predispose to P-ADC in humans. Our objective was to explore whether exposure to domestic small ruminants may represent a risk factor for P-ADC. We performed a multicenter case-control study recruiting patients with P-ADC as cases and patients with non-P-ADC non-small cell lung cancer as controls. A dedicated 356-item questionnaire was built to evaluate exposure to livestock. A total of 44 cases and 132 controls were included. At multivariate analysis, P-ADC was significantly more associated with female gender (Odds-ratio (OR) = 3.23, 95% confidence interval (CI): 1.32–7.87, p = 0.010), never- smoker status (OR = 3.57, 95% CI: 1.27–10.00, p = 0.015), personal history of extra-thoracic cancer before P-ADC diagnosis (OR = 3.43, 95% CI: 1.10–10.72, p = 0.034), and professional exposure to goats (OR = 5.09, 95% CI: 1.05–24.69, p = 0.043), as compared to other subtypes of lung cancer. This case-control suggests a link between professional exposure to goats and P-ADC, and prompts for further epidemiological evaluation of potential environmental risk factors for P-ADC.
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Affiliation(s)
- Delphine Lutringer-Magnin
- Hospices Civils de Lyon, Lyon, France
- Université de Lyon, Lyon, France
- Université Claude Bernard Lyon 1, Lyon, France
- UMR 5558 CNRS, Laboratoire de biométrie et biologie évolutive, Lyon, France
| | - Nicolas Girard
- Hospices Civils de Lyon, Lyon, France
- Université de Lyon, Lyon, France
- Université Claude Bernard Lyon 1, Lyon, France
- UMR754 INRA, Rétrovirus et pathologie comparée, Lyon, France
| | | | - Caroline Leroux
- Université de Lyon, Lyon, France
- Université Claude Bernard Lyon 1, Lyon, France
- UMR754 INRA, Rétrovirus et pathologie comparée, Lyon, France
| | - Elisabeth Quoix
- Service de pneumologie, Hôpital Hautepierre, Strasbourg, France
| | - Vincent Cottin
- Hospices Civils de Lyon, Lyon, France
- Université de Lyon, Lyon, France
- Université Claude Bernard Lyon 1, Lyon, France
- UMR754 INRA, Rétrovirus et pathologie comparée, Lyon, France
| | - Corinne Del Signore
- Université de Lyon, Lyon, France
- Université Claude Bernard Lyon 1, Lyon, France
- UMR 5558 CNRS, Laboratoire de biométrie et biologie évolutive, Lyon, France
| | | | - Geneviève Cordier
- Université de Lyon, Lyon, France
- Université Claude Bernard Lyon 1, Lyon, France
- UMR754 INRA, Rétrovirus et pathologie comparée, Lyon, France
| | - Philippe Vanhems
- Hospices Civils de Lyon, Lyon, France
- Université de Lyon, Lyon, France
- Université Claude Bernard Lyon 1, Lyon, France
- UMR 5558 CNRS, Laboratoire de biométrie et biologie évolutive, Lyon, France
| | - Jean-François Mornex
- Hospices Civils de Lyon, Lyon, France
- Université de Lyon, Lyon, France
- Université Claude Bernard Lyon 1, Lyon, France
- UMR754 INRA, Rétrovirus et pathologie comparée, Lyon, France
- * E-mail:
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Qi JW, Wu XL, Liu SY, Cao GF. Expression of endogenous beta retroviruses and Hyal-2 mRNA in immune organs of fetuses and lambs. Virol Sin 2012; 27:83-92. [PMID: 22491999 DOI: 10.1007/s12250-012-3222-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Accepted: 02/09/2012] [Indexed: 10/28/2022] Open
Abstract
Endogenous beta retroviruses (enJSRV) are highly homologous with Jaagsiekte sheep retrovirus (exJSRV), this exogenous retrovirus is the aetiological agent of ovine pulmonary adenocarcinoma (OPA). The aim of this study was to clarify the function of enJSRV and the immunological mechanisms of its corresponding antibody, that is undetectable in JSRV-infected ovine serum. The expression of enJSRV envelope protein and Hyal-2 mRNA in immune organs and lungs of ovine fetuses and lambs were analyzed by Real-Time reverse transcription PCR and In Situ Hybridization using specific probes. In Situ Hybridization results indicated that the enJSRV envelope protein and Hyal-2 mRNA were expressed in thymus, spleen, mesenteric lymph nodes and lungs at different times, while no positive signals were detected in the negative controls. On the other hand, results from Real-Time reverse transcription PCR analysis showed that in 130d fetuses and 3d newborn lambs the enJSRV mRNA levels were much higher in organs associated with the immune system than that in lungs, especially in the thymus and spleen, but levels of Hyal-2 mRNA expression was not significantly different in all collected tissue. These results provided evidence from an immunology point of view to understand why the circulating antibodies against exJSRV are undetectable in JSRV-infected ovine, and will help to unravel the pathogenesis of JSRV-infected ovine.
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Affiliation(s)
- Jing-wei Qi
- College of Animal Science and Veterinary Medicine, Inner Mongolia Agricultural University, Huhhot, 010018, China
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14
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Côté M, Zheng YM, Albritton LM, Liu SL. Single residues in the surface subunits of oncogenic sheep retrovirus envelopes distinguish receptor-mediated triggering for fusion at low pH and infection. Virology 2011; 421:173-83. [PMID: 22018783 DOI: 10.1016/j.virol.2011.09.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2011] [Revised: 09/13/2011] [Accepted: 09/24/2011] [Indexed: 11/25/2022]
Abstract
Jaagsiekte sheep retrovirus (JSRV) and enzootic nasal tumor virus (ENTV) are two closely related oncogenic retroviruses that share the same cellular receptor yet exhibit distinct fusogenicity and infectivity. Here, we find that the low fusogenicity of ENTV envelope protein (Env) is not because of receptor binding, but lies in its intrinsic insensitivity to receptor-mediated triggering for fusion at low pH. Distinct from JSRV, shedding of ENTV surface (SU) subunit into culture medium was not enhanced by a soluble form of receptor, Hyal2 (sHyal2), and sHyal2 was unable to effectively inactivate the ENTV pseudovirions. Remarkably, replacing either of the two amino acid residues, N191 or S195, located in the ENTV SU with the corresponding JSRV residues, H191 or G195, markedly increased the Env-mediated membrane fusion activity and infection. Reciprocal amino acid substitutions also partly switched the sensitivities of ENTV and JSRV pseudovirions to sHyal2-mediated SU shedding and inactivation. While N191 is responsible for an extra N-linked glycosylation of ENTV SU relative to that of JSRV, S195 possibly forms a hydrogen bond with a surrounding amino acid residue. Molecular modeling of the pre-fusion structure of JSRV Env predicts that the segment of SU that contains H191 to G195 contacts the fusion peptide and suggests that the H191N and G195S changes seen in ENTV may stabilize its pre-fusion structure against receptor priming and therefore modulate fusion activation by Hyal2. In summary, our study reveals critical determinants in the SU subunits of JSRV and ENTV Env proteins that likely regulate their local structures and thereby differential receptor-mediated fusion activation at low pH, and these findings explain, at least in part, their distinct viral infectivity.
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Affiliation(s)
- Marceline Côté
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada H3A 2B4
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15
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Jaagsiekte sheep retrovirus and enzootic nasal tumor virus promoters drive gene expression in all airway epithelial cells of mice but only induce tumors in the alveolar region of the lungs. J Virol 2011; 85:7535-45. [PMID: 21593165 DOI: 10.1128/jvi.00400-11] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Jaagsiekte sheep retrovirus (JSRV) induces tumors in the distal airways of sheep and goats, while the closely related enzootic nasal tumor virus type 1 (ENTV-1) and ENTV-2 induce tumors in the nasal epithelium of sheep and goats, respectively. When expressed using a strong Rous sarcoma virus promoter, the envelope proteins of these viruses induce tumors in the respiratory tract of mice, but only in the distal airway. To examine the role of the retroviral long terminal repeat (LTR) promoters in determining tissue tropism, adeno-associated virus (AAV) vectors expressing alkaline phosphatase under the control of the JSRV, ENTV-1, or ENTV-2 LTRs were generated and administered to mice. The JSRV LTR was active in all airway epithelial cells, while the ENTV LTRs were active in the nasal epithelium and alveolar type II cells but poorly active in tracheal and bronchial epithelial cells. When vectors were administered systemically, the ENTV-1 and -2 LTRs were inactive in major organs examined, whereas the JSRV showed high-level activity in the liver. When a putative transcriptional enhancer from the 3' end of the env gene was inserted upstream of the JSRV and ENTV-1 LTRs in the AAV vectors, a dramatic increase in transgene expression was observed. However, intranasal administration of AAV vectors containing any combination of ENTV or JSRV LTRs and Env proteins induced tumors only in the lower airway. Our results indicate that mice do not provide an adequate model for nasal tumor induction by ENTV despite our ability to express genes in the nasal epithelium.
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16
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Murgia C, Caporale M, Ceesay O, Di Francesco G, Ferri N, Varasano V, de las Heras M, Palmarini M. Lung adenocarcinoma originates from retrovirus infection of proliferating type 2 pneumocytes during pulmonary post-natal development or tissue repair. PLoS Pathog 2011; 7:e1002014. [PMID: 21483485 PMCID: PMC3068994 DOI: 10.1371/journal.ppat.1002014] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Accepted: 02/04/2011] [Indexed: 01/06/2023] Open
Abstract
Jaagsiekte sheep retrovirus (JSRV) is a unique oncogenic virus with distinctive biological properties. JSRV is the only virus causing a naturally occurring lung cancer (ovine pulmonary adenocarcinoma, OPA) and possessing a major structural protein that functions as a dominant oncoprotein. Lung cancer is the major cause of death among cancer patients. OPA can be an extremely useful animal model in order to identify the cells originating lung adenocarcinoma and to study the early events of pulmonary carcinogenesis. In this study, we demonstrated that lung adenocarcinoma in sheep originates from infection and transformation of proliferating type 2 pneumocytes (termed here lung alveolar proliferating cells, LAPCs). We excluded that OPA originates from a bronchioalveolar stem cell, or from mature post-mitotic type 2 pneumocytes or from either proliferating or non-proliferating Clara cells. We show that young animals possess abundant LAPCs and are highly susceptible to JSRV infection and transformation. On the contrary, healthy adult sheep, which are normally resistant to experimental OPA induction, exhibit a relatively low number of LAPCs and are resistant to JSRV infection of the respiratory epithelium. Importantly, induction of lung injury increased dramatically the number of LAPCs in adult sheep and rendered these animals fully susceptible to JSRV infection and transformation. Furthermore, we show that JSRV preferentially infects actively dividing cell in vitro. Overall, our study provides unique insights into pulmonary biology and carcinogenesis and suggests that JSRV and its host have reached an evolutionary equilibrium in which productive infection (and transformation) can occur only in cells that are scarce for most of the lifespan of the sheep. Our data also indicate that, at least in this model, inflammation can predispose to retroviral infection and cancer.
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Affiliation(s)
- Claudio Murgia
- Medical Research Council – University of Glasgow Centre for Virus Research, Institute of Infection, Inflammation and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, United Kingdom
| | - Marco Caporale
- Medical Research Council – University of Glasgow Centre for Virus Research, Institute of Infection, Inflammation and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, United Kingdom
- Istituto G. Caporale, Teramo, Italy
| | - Ousman Ceesay
- Medical Research Council – University of Glasgow Centre for Virus Research, Institute of Infection, Inflammation and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, United Kingdom
| | | | | | - Vincenzo Varasano
- Dipartimento di Scienze Cliniche Veterinarie, Facolta' di Medicina Veterinaria, Universita' di Teramo, Italy
| | | | - Massimo Palmarini
- Medical Research Council – University of Glasgow Centre for Virus Research, Institute of Infection, Inflammation and Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, United Kingdom
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17
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Jaagsiekte sheep retrovirus biology and oncogenesis. Viruses 2010; 2:2618-48. [PMID: 21994634 PMCID: PMC3185594 DOI: 10.3390/v2122618] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Revised: 11/22/2010] [Accepted: 11/23/2010] [Indexed: 11/19/2022] Open
Abstract
Jaagsiekte sheep retrovirus (JSRV) is the causative agent of a lung cancer in sheep known as ovine pulmonary adenocarcinoma (OPA). The disease has been identified around the world in several breeds of sheep and goats, and JSRV infection typically has a serious impact on affected flocks. In addition, studies on OPA are an excellent model for human lung carcinogenesis. A unique feature of JSRV is that its envelope (Env) protein functions as an oncogene. The JSRV Env-induced transformation or oncogenesis has been studied in a variety of cell systems and in animal models. Moreover, JSRV studies have provided insights into retroviral genomic RNA export/expression mechanisms. JSRV encodes a trans-acting factor (Rej) within the env gene necessary for the synthesis of Gag protein from unspliced viral RNA. This review summarizes research pertaining to JSRV-induced pathogenesis, Env transformation, and other aspects of JSRV biology.
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18
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Varela M, Palmarini M. Multitasking: Making the Most out of the Retroviral Envelope. Viruses 2010; 2:1571-1576. [PMID: 21994694 PMCID: PMC3185736 DOI: 10.3390/v2081571] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Revised: 07/26/2010] [Accepted: 07/26/2010] [Indexed: 11/16/2022] Open
Abstract
Evasion of the host's immune system is a required step for the establishment of viral infection. In this article, we discuss the recent findings of Heidmann and colleagues demonstrating that some retroviruses possess an immune suppressive (IS) domain "encrypted" within their envelope glycoprotein that is required to establish a successful infection in immunocompetent hosts [1].
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Affiliation(s)
- Mariana Varela
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, CB3 0ES,Cambridge, England, UK; E-Mail:
| | - Massimo Palmarini
- Medical Research Council - University of Glasgow Centre for Virus Research, Institute for Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Scotland, UK
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +44-141-330-6288; Fax: +44-141-330-2271
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Hudachek SF, Kraft SL, Thamm DH, Bielefeldt-Ohmann H, DeMartini JC, Miller AD, Dernell WS. Lung Tumor Development and Spontaneous Regression in Lambs Coinfected With Jaagsiekte Sheep Retrovirus and Ovine Lentivirus. Vet Pathol 2010; 47:148-62. [DOI: 10.1177/0300985809352787] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Ovine pulmonary adenocarcinoma (OPA) is a naturally occurring and experimentally inducible lung cancer of sheep caused by Jaagsiekte sheep retrovirus (JSRV). The first aim of this study was to monitor the development of OPA with minimally invasive, real-time observations of animals experimentally infected with JSRV as well as ovine lentivirus (maedi-visna virus). Worldwide, simultaneous infection of sheep with these 2 retroviruses is a common occurrence, naturally and experimentally; consequently, the lung tumor homogenates used as inocula contained both viruses. Following inoculation, computed tomography was used to detect tumor nodules early, before the onset of clinical signs, and to monitor tumor advancement. However, not only was OPA disease progression observed, but the apparent spontaneous regression of OPA was witnessed. In fact, regression was more common than progression following JSRV inoculation of neonatal lambs. Immune responses were detected, particularly involving CD3+ T cells and the production of antibodies against JSRV that may mediate the spontaneous regression of JSRV-induced OPA. The second aim of this study was to determine whether OPA tumors harbor genetic alterations similar to those found in human lung adenocarcinoma. No mutations were found in the tyrosine kinase domain of the epidermal growth factor receptor, KRAS codons 12 and 13, or the DNA-binding domain of p53 in tumor DNA from naturally occurring and experimentally-induced OPA cases. Overall, the genetic profile combined with the disease development data provides further important characterization of OPA and describes, for the first time, spontaneous regression of OPA tumors in experimentally infected sheep.
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Affiliation(s)
- S. F. Hudachek
- Animal Cancer Center, Colorado State University, Fort Collins
| | - S. L. Kraft
- Animal Cancer Center, Colorado State University, Fort Collins
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins
| | - D. H. Thamm
- Animal Cancer Center, Colorado State University, Fort Collins
- Department of Clinical Sciences, Colorado State University, Fort Collins
| | - H. Bielefeldt-Ohmann
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins
- Present address: School of Veterinary Science, University of Queensland, St. Lucia, Australia
| | - J. C. DeMartini
- Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins
| | - A. D. Miller
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington
| | - W. S. Dernell
- Animal Cancer Center, Colorado State University, Fort Collins
- Department of Veterinary Clinical Sciences, Washington State University, Pullman
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Chitra E, Yu SL, Hsiao KN, Shao HY, Sia C, Chen IH, Hsieh SY, Chen JH, Chow YH. Generation and characterization of JSRV envelope transgenic mice in FVB background. Virology 2009; 393:120-6. [DOI: 10.1016/j.virol.2009.07.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Revised: 05/29/2009] [Accepted: 07/22/2009] [Indexed: 01/23/2023]
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21
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Maeda N, Fan H, Yoshikai Y. Oncogenesis by retroviruses: old and new paradigms. Rev Med Virol 2008; 18:387-405. [PMID: 18729235 DOI: 10.1002/rmv.592] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Retroviruses are associated with a variety of diseases including an array of malignancies, immunodeficiencies and neurological disorders. In particular, studies of oncogenic retroviruses established fundamental principles of modern molecular cancer biology. Studies of avian Rous sarcoma virus (RSV) led to the discovery of the viral oncogene src, and this was followed by the discovery of other viral oncogenes in retroviruses of mammals including rodents, cats, monkeys and so forth. Studies of the viral oncogenes in turn led to the discovery of cellular proto-oncogenes in the host genome; cellular oncogenes have been shown to be activated in a variety of human cancers, including those with no viral involvement. Oncogenic animal retroviruses can be divided into two groups based on their mechanisms of tumourigenesis, acute transforming retroviruses and nonacute retroviruses. Acute transforming retroviruses are typically replication defective and they induce tumours rapidly due to expression of their viral oncogenes. Nonacute retroviruses are replication competent and they induce tumours with longer latencies, by activating cellular proto-oncogenes in the tumour cells; this results from insertion of proviral DNA in the vicinity of the activated proto-oncogene. More recently, human T-cell leukaemia virus type I (HTLV-I) was discovered as an etiological agent of human cancer (adult T-cell leukaemia [ATL]); this virus also encodes regulatory genes some of which are important for its oncogenic potential. Most recently, the retroviral structural protein Envelope (Env) has been shown to be directly involved in oncogenic transformation for certain retroviruses. Env-induced transformation is a new paradigm for retroviral oncogenesis. In this review, we will summarise research on retrovirus oncogenic transformation over the past 100 years since the first published report of an oncogenic virus with particular attention to Env-induced transformation.
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Affiliation(s)
- Naoyoshi Maeda
- Division of Host Defense, Research Center for Prevention of Infectious Diseases, Medical Institute of Bioregulation, Kyushu University, Higashi-ku, Fukuoka, Japan.
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A placenta-specific receptor for the fusogenic, endogenous retrovirus-derived, human syncytin-2. Proc Natl Acad Sci U S A 2008; 105:17532-7. [PMID: 18988732 DOI: 10.1073/pnas.0807413105] [Citation(s) in RCA: 148] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Syncytin-2 is an envelope gene from the human endogenous retrovirus FRD (HERV-FRD) co-opted by an ancestral primate host, conserved in evolution over >40 Myr, specifically expressed in the placenta, and with a cell-cell fusogenic activity likely contributing to placenta morphogenesis. Here, using the GeneBridge4 human/Chinese hamster radiation hybrid panel, we mapped and identified the human receptor for syncytin-2. This receptor-namely Major Facilitator Superfamily Domain Containing 2 (MFSD2)-belongs to a large family of presumptive carbohydrate transporters with 10-12 membrane-spanning domains, is located at chromosomal position 1p34.2, and is conserved in evolution. An expression vector for MFSD2 confers fusogenicity to otherwise insusceptible cells upon transfection of syncytin-2. It also confers infectivity to syncytin-2 pseudotypes, consistent with this protein being the receptor for the ancestrally acquired HERV-FRD family of endogenous retroviruses. At variance with the human gene, neither mouse nor rat MFSD2 can mediate membrane fusion, which is consistent with the fact that the envelope-derived syncytin genes co-opted by rodents during evolution are not orthologous to the human syncytin genes. Remarkably, a real-time quantitative RT-PCR analysis of MFSD2 in various human tissues demonstrates specific expression in the placenta, as well as in the human BeWo choriocarcinoma cell line, which discloses enhancement of receptor expression upon induction by forskolin of cell-cell fusion and syncytium formation. In situ hybridization of human placental tissue using an MFSD2-specific probe further unambiguously demonstrates receptor expression at the level of the syncytiotrophoblast, again consistent with a role in placenta morphogenesis.
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Enzootic nasal tumor virus envelope requires a very acidic pH for fusion activation and infection. J Virol 2008; 82:9023-34. [PMID: 18632865 DOI: 10.1128/jvi.00648-08] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Enzootic nasal tumor virus (ENTV) is a close relative of jaagsiekte sheep retrovirus (JSRV), and the two viruses use the same receptor, hyaluronidase 2 (Hyal2), for cell entry. We report here that, unlike the JSRV envelope (Env) protein, the ENTV Env protein does not induce cell fusion at pHs of 5.0 and above but requires a much lower pH (4.0 to 4.5) for fusion to occur. The entry of ENTV Env pseudovirions was substantially inhibited by bafilomycin A1 (BafA1) but was surprisingly enhanced by lysosomotropic agents and lysosomal protease inhibitors following a 4- to 6-h treatment period; of note, prolonged treatment with BafA1 or ammonium chloride completely blocked ENTV entry. Unlike typical pH-dependent viruses, ENTV Env pseudovirions were virtually resistant to inactivation at a low pH (4.5 or 5.0). Using chimeras formed from ENTV and JSRV Env proteins, we demonstrated that the transmembrane (TM) subunit of ENTV Env is primarily responsible for its unusually low pH requirement for fusion but found that the surface (SU) subunit of ENTV Env also critically influences its relatively low and pH-dependent fusion activity. Furthermore, the poor infectivity of ENTV pseudovirions in human cells was significantly improved by either replacing the SU subunit of ENTV Env with that of JSRV Env or overexpressing the functional Hyal2 receptor in target cells, suggesting that ENTV SU-Hyal2 interaction is likely to be the limiting step for viral infectivity. Collectively, our data reveal that the fusogenicity of ENTV Env is intrinsically lower than that of JSRV Env and that ENTV requires a more acidic pH for fusion, which may occur in an intracellular compartment(s) distinct from that used by JSRV.
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Miller AD. Hyaluronidase 2 and its intriguing role as a cell-entry receptor for oncogenic sheep retroviruses. Semin Cancer Biol 2008; 18:296-301. [PMID: 18485731 DOI: 10.1016/j.semcancer.2008.03.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2008] [Accepted: 03/19/2008] [Indexed: 10/22/2022]
Abstract
Jaagsiekte sheep retrovirus (JSRV) causes lung adenocarcinoma in sheep and goats, while the closely related enzootic nasal tumor virus (ENTV) causes nasal tumors in the same species. The envelope (Env) protein from either virus can transform fibroblasts and epithelial cells in culture, indicating that the Env proteins are responsible for tumorigenesis. However, the primary function of retroviral Env proteins is to mediate virus entry into cells by interacting with specific cell-surface receptors, suggesting that the virus receptor might be a key player in transformation as well. Thus, identification of Hyaluronidase-2 (Hyal2) as the cell-entry receptor for both JSRV and ENTV suggested a role for Hyal2 in oncogenesis. Furthermore, Hyal2 is located in a key lung cancer tumor suppressor locus on chromosome 3p21.3, suggesting that Hyal2 might have a tumor suppressor activity that was disrupted by Env thereby leading to tumorigenesis. However, recent experiments showing that expression of the JSRV or ENTV Env protein in mouse lung can induce lung tumors, even though the viral Env proteins cannot bind to or utilize mouse Hyal2 as a receptor for virus entry into cells, indicate that Hyal2 plays no role in cancer induction by these retroviruses. Hyal2 remains an enigmatic member of the hyaluronidase family given its very low hyaluronidase activity in purified form or when expressed in cultured cells, suggesting that it may have evolved to perform some other as yet unknown function.
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Affiliation(s)
- A Dusty Miller
- Division of Human Biology, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109-1024, USA.
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26
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[New molecular mechanisms of virus-mediated carcinogenesis: oncogenic transformation of cells by retroviral structural protein Envelope]. Uirusu 2008; 57:159-70. [PMID: 18357754 DOI: 10.2222/jsv.57.159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
RNA tumor viruses as classified in Retroviruses have been isolated and identified to induce tumors in a variety of animals including chickens, mice, and rats, or even in human in the last 100 years, since the first one has been reported in 1908. The RNA tumor viruses have been historically classified into two groups, acute transforming RNA tumor viruses and nonacute RNA tumor viruses. Acute transforming RNA tumor viruses are basically replication-defective and rapidly induce tumors by expressing the viral oncogenes captured from cellular genome in host cells. The first oncogene derived from Rous sarcoma virus was the src non-receptor tyrosine kinase, which has been identified to play the significant roles for signal transduction. On the other hand, nonacute RNA tumor viruses, which consist of only gag, pro, pol, and env regions but do not carry oncogenes, are replication-competent and could activate the cellular proto-oncogenes by inserting the viral long terminal repeat close to the proto-oncogenes to induce tumors with a long incubation period, as is termed a promoter insertion. These molecular mechanisms have been thought to induce tumors. However, very recently several reports have described that the retroviral structural protein Envelope could directly induce tumors in vivo and transform cells in vitro. These are very unusual examples of native retroviral structural proteins with transformation potential. In this review we look back over the history of oncogenic retrovirus research and summarize recent progress for our understanding of the molecular mechanisms of oncogenic transformation by retrovirus Envelope proteins.
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Côté M, Zheng YM, Albritton LM, Liu SL. Fusogenicity of Jaagsiekte sheep retrovirus envelope protein is dependent on low pH and is enhanced by cytoplasmic tail truncations. J Virol 2008; 82:2543-54. [PMID: 18094165 PMCID: PMC2258932 DOI: 10.1128/jvi.01852-07] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2007] [Accepted: 12/13/2007] [Indexed: 01/05/2023] Open
Abstract
Jaagsiekte sheep retrovirus (JSRV) envelope (Env) is an active oncogene responsible for neoplastic transformation in animals and cultured cells. In this study, we used syncytium induction and fluorescence-based cell fusion assays to investigate JSRV Env fusion and its modulation by the cytoplasmic tail (CT). We found that JSRV Env induced syncytia in cells overexpressing the receptor for JSRV and that a low pH was required for this process to occur. Fusion kinetics studies revealed that cell-cell fusion by JSRV Env at neutral pH was poor, taking up to a day, in sharp contrast to fusion at low pH, which peaked within 2 min following a low-pH trigger. Deletion of the C-terminal 7 or 16 amino acids of the JSRV Env CT had no or little effect on fusion, yet additional truncation toward the membrane-spanning domain, resulting in mutants retaining as little as 1 amino acid of the CT, led to progressively increased syncytium formation at neutral pH that was further enhanced by low-pH treatment. Notably, the severely truncated mutants showed elevated levels of surface subunits in culture medium, suggesting that the CT truncations resulted in conformational changes in the ectodomain of Env that impaired surface subunit associations. Taken together, this study reveals for the first time that the fusion activity of the JSRV Env protein is dependent on a low pH and is modulated by the CT, whose truncation overcomes, at least partially, the low-pH requirement for fusion and enhances Env fusion activity and kinetics.
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Affiliation(s)
- Marceline Côté
- McGill University, Department of Microbiology and Immunology, 3775 University St., Montreal, QC H3A 2B4, Canada.
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28
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McGee-Estrada K, Fan H. Comparison of LTR enhancer elements in sheep betaretroviruses: insights into the basis for tissue-specific expression. Virus Genes 2007; 35:303-12. [PMID: 17268841 DOI: 10.1007/s11262-007-0079-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2006] [Accepted: 01/10/2007] [Indexed: 11/27/2022]
Abstract
Jaagsiekte sheep retrovirus (JSRV), enzootic nasal tumor virus (ENTV), and endogenous sheep retroviruses (ESRVs) are highly related sheep betaretroviruses that display different expression profiles in vivo. JSRV and ENTV are expressed in lungs and nasal adenocarcinomas, respectively, while ESRVs are primarily expressed in the reproductive tract of ewes. Evidence suggests that the cell tropism of JSRV, ENTV, and ESRVs is due to the transcriptional specificity of the LTRs. We have previously found several enhancer elements in the JSRV LTR that are important for lung-specific expression, including binding sites for the lung-specific transcription factor HNF-3beta, as well as binding sites for the ubiquitously expressed transcription factors C/EBP and NF-I. In this study, we have aligned the U3 regions of JSRV, ENTV, and several ESRVs in order to compare the transcriptional enhancer elements of JSRV that are conserved or absent in ESRV and ENTV. All three JSRV U3 sequences examined contain two conserved HNF-3 binding sites, while the ENTV and ESRV U3 regions are not predicted to bind this transcription factor. In addition, the C/EBP binding site is interrupted in the ESRV LTRs, but conserved in the ENTV LTRs. Some enhancer elements are conserved between JSRV and ENTV, but a reporter vector carrying the ENTV-1 LTR showed less activity than a JSRV LTR-driven reporter vector in a lung epithelial cell line. These studies support the importance of LTR enhancer elements in the respective tissue specificities of these exogenous and endogenous betaretroviruses.
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Spencer TE, Johnson GA, Bazer FW, Burghardt RC, Palmarini M. Pregnancy recognition and conceptus implantation in domestic ruminants: roles of progesterone, interferons and endogenous retroviruses. Reprod Fertil Dev 2007; 19:65-78. [PMID: 17389136 DOI: 10.1071/rd06102] [Citation(s) in RCA: 215] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The present review highlights new information on pregnancy recognition and conceptus development and implantation in sheep with respect to regulation by progesterone, interferons and endogenous retroviruses. After formation of the corpus luteum, progesterone acts on the endometrium and stimulates blastocyst growth and elongation to a filamentous conceptus (embryo/fetus and associated extra-embryonic membranes). The envelope of endogenous retroviruses related to Jaagsiekte sheep retroviruses appears to intrinsically regulate mononuclear trophectoderm cell proliferation and differentiation into trophoblast giant binucleate cells. The mononuclear trophectoderm cells of elongating sheep conceptuses secrete interferon-tau, which acts on the endometrium to prevent development of the luteolytic mechanism by inhibiting transcription of the gene for the oestrogen receptor alpha in the luminal and superficial ductal glandular epithelia. These actions prevent oestrogen-induced transcription of the oxytocin receptor gene and, therefore, oxytocin-induced luteolytic pulses of prostaglandin F2alpha. Progesterone down regulation of its receptors in luminal and glandular epithelia correlates temporally with a reduction in anti-adhesive mucin land induction of secreted galectin 15 (LGALSI5) and secreted phosphoprotein 1, which are proposed to regulate trophectoderm proliferation and adhesion. Interferon-c acts on the endometrial lumenal epithelium to induce WNT7A and to stimulate LGALS 15, cathepsin L and cystatin C, which are candidate regulators of conceptus development and implantation. The number of potential contributors to maternal recognition and establishment of pregnancy continues to grow and this highlights our limited appreciation of the complexity of the key molecules and signal transduction pathways that intersect during these key developmental processes. The goal of improving reproductive efficiency by preventing embryonic losses that occur during the peri-implantation period of pregnancy in domestic ruminants provides the challenge to increase our knowledge of endometrial function and conceptus development.
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Affiliation(s)
- Thomas E Spencer
- Center for Animal Biotechnology andGenomics, Department of Animal Science, Texas A&M University, College Station, TX 77843, USA.
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Leroux C, Girard N, Cottin V, Greenland T, Mornex JF, Archer F. Jaagsiekte Sheep Retrovirus (JSRV): from virus to lung cancer in sheep. Vet Res 2007; 38:211-28. [PMID: 17257570 DOI: 10.1051/vetres:2006060] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2006] [Accepted: 11/23/2006] [Indexed: 01/16/2023] Open
Abstract
Jaagsiekte Sheep Retrovirus (JSRV) is a betaretrovirus infecting sheep. This virus is responsible for a pulmonary adenocarcinoma, by transformation of epithelial cells from the bronchioli and alveoli. This animal cancer is similar to human bronchioloalveolar cancer (BAC), a specific form of human lung cancer for which a viral aetiology has not yet been identified. JSRV interacts with target cells through the membrane receptor Hyal2. The JSRV genome is simple and contains no recognised oncogene. It is now well established that the viral envelope protein is oncogenic by itself, via the cytoplasmic domain of the transmembrane glycoprotein and some domains of the surface glycoprotein. Activation of the PI3K/Akt and MAPK pathways participates in the envelope-induced transformation. Tumour development is associated with telomerase activation. This review will focus on the induction of cancer by JSRV.
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Affiliation(s)
- Caroline Leroux
- Université de Lyon 1, INRA, UMR754, Ecole Nationale Vétérinaire de Lyon, IFR 128, F-69007, Lyon, France.
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31
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Flotte TR, Ng P, Dylla DE, McCray PB, Wang G, Kolls JK, Hu J. Viral Vector–mediated and Cell-based Therapies for Treatment of Cystic Fibrosis. Mol Ther 2007; 15:229-41. [PMID: 17235299 DOI: 10.1038/sj.mt.6300002] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Gene and cell-based therapies are considered to be potentially powerful new approaches for the management of cystic fibrosis (CF) lung disease. Despite tremendous efforts that have been made, especially in studies to understand the obstacles to gene delivery, major challenges to the application of these approaches remain to be solved. This article will review the advancements made and challenges remaining in the development of viral vector-mediated and cell-based approaches to treat patients with CF.
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Affiliation(s)
- Terence R Flotte
- Department of Pediatrics, University of Florida, Gainesville, Florida, USA
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32
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Wootton SK, Metzger MJ, Hudkins KL, Alpers CE, York D, DeMartini JC, Miller AD. Lung cancer induced in mice by the envelope protein of jaagsiekte sheep retrovirus (JSRV) closely resembles lung cancer in sheep infected with JSRV. Retrovirology 2006; 3:94. [PMID: 17177996 PMCID: PMC1764900 DOI: 10.1186/1742-4690-3-94] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2006] [Accepted: 12/19/2006] [Indexed: 11/23/2022] Open
Abstract
Background Jaagsiekte sheep retrovirus (JSRV) causes a lethal lung cancer in sheep and goats. Expression of the JSRV envelope (Env) protein in mouse lung, by using a replication-defective adeno-associated virus type 6 (AAV6) vector, induces tumors resembling those seen in sheep. However, the mouse and sheep tumors have not been carefully compared to determine if Env expression alone in mice can account for the disease features observed in sheep, or whether additional aspects of virus replication in sheep are important, such as oncogene activation following retrovirus integration into the host cell genome. Results We have generated mouse monoclonal antibodies (Mab) against JSRV Env and have used these to study mouse and sheep lung tumor histology. These Mab detect Env expression in tumors in sheep infected with JSRV from around the world with high sensitivity and specificity. Mouse and sheep tumors consisted mainly of well-differentiated adenomatous foci with little histological evidence of anaplasia, but at long times after vector exposure some mouse tumors did have a more malignant appearance typical of adenocarcinoma. In addition to epithelial cell tumors, lungs of three of 29 sheep examined contained fibroblastic cell masses that expressed Env and appeared to be separate neoplasms. The Mab also stained nasal adenocarcinoma tissue from one United States sheep, which we show was due to expression of Env from ovine enzootic nasal tumor virus (ENTV), a virus closely related to JSRV. Systemic administration of the AAV6 vector encoding JSRV Env to mice produced numerous hepatocellular tumors, and some hemangiomas and hemangiosarcomas, showing that the Env protein can induce tumors in multiple cell types. Conclusion Lung cancers induced by JSRV infection in sheep and by JSRV Env expression in mice have similar histologic features and are primarily characterized by adenomatous proliferation of peripheral lung epithelial cells. Thus it is unnecessary to invoke a role for insertional mutagenesis, gene activation, viral replication, or expression of other viral gene products in sheep lung tumorigenesis, although these processes may play a role in other clinically less important sequelae of JSRV infection such as metastasis observed with variable frequency in sheep.
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Affiliation(s)
- Sarah K Wootton
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
| | - Michael J Metzger
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
| | - Kelly L Hudkins
- Department of Pathology, University of Washington, Seattle, Washington 98195, USA
| | - Charles E Alpers
- Department of Pathology, University of Washington, Seattle, Washington 98195, USA
| | - Denis York
- Molecular Diagnostic Services, Westville 3630, South Africa
| | - James C DeMartini
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523, USA
| | - A Dusty Miller
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
- Department of Pathology, University of Washington, Seattle, Washington 98195, USA
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Abstract
Retroviruses have played profound roles in our understanding of the genetic and molecular basis of cancer. Jaagsiekte sheep retrovirus (JSRV) is a simple retrovirus that causes contagious lung tumors in sheep, known as ovine pulmonary adenocarcinoma (OPA). Intriguingly, OPA resembles pulmonary adenocarcinoma in humans, and may provide a model for this frequent human cancer. Distinct from the classical mechanisms of retroviral oncogenesis by insertional activation of or virus capture of host oncogenes, the native envelope (Env) structural protein of JSRV is itself the active oncogene. A major pathway for Env transformation involves interaction of the Env cytoplasmic tail with as yet unidentified cellular adaptor(s), leading to the activation of PI3K/Akt and MAPK signaling cascades. Another potential mechanism involves the cell-entry receptor for JSRV, Hyaluronidase 2 (Hyal2), and the RON receptor tyrosine kinase, but the exact roles of these proteins in JSRV Env transformation remain to be better understood. Recently, a mouse model of lung cancer induced by JSRV Env has been developed, and the tumors in mice resemble those seen in sheep infected with JSRV and in humans. In this review, we summarize recent progress in our understanding the molecular mechanisms of oncogenic transformation by JSRV Env protein, and discuss the relevance to human lung cancer.
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Affiliation(s)
- S-L Liu
- Department of Microbiology and Immunology, McGill University, Montreal, Canada.
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Philbey AW, Cousens C, Bishop JV, Gill CA, DeMartini JC, Sharp JM. Multiclonal pattern of Jaagsiekte sheep retrovirus integration sites in ovine pulmonary adenocarcinoma. Virus Res 2005; 117:254-63. [PMID: 16310879 DOI: 10.1016/j.virusres.2005.10.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2005] [Revised: 10/25/2005] [Accepted: 10/31/2005] [Indexed: 11/21/2022]
Abstract
Insertional mutagenesis and envelope (Env)-mediated oncogenesis are hypothesized mechanisms by which Jaagsiekte sheep retrovirus (JSRV) causes ovine pulmonary adenocarcinoma (OPA). Twenty-eight JSRV integration sites in lung tumors (LTs) from four sheep with OPA were cloned and sequenced by a multiple step gene walking technique. Using nested PCR, clonal expansion of these integration sites could be detected, if at all, only in the localized regions of LT from which the integration sites were derived. One sheep had a viral integration site in a sequence with 85 and 81% identity, respectively, over 100 bp to exon 2 of the human and mouse receptor protein tyrosine phosphatase gamma genes. Clonal integration of Jaagsiekte sheep retrovirus in this gene was demonstrated by nested PCR and Southern blot hybridization in the DNA sample from which the integration site was cloned, but not in other LT or kidney DNA samples from the same sheep. OPA may develop from multiple independent oncogenic events and a role for insertional mutagenesis cannot be ruled out.
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Abstract
Enveloped virus vectors are used in a wide variety of applications. We have discovered that treatment of cultured cells with phosphatidylserine (PS) liposomes can increase virus vector infection by up to 20-fold. This effect does not abrogate virus receptor requirements, is specific to PS compared to other phospholipids, and is limited to enveloped viruses. Furthermore, the enhancement of infection does not occur through increases in virus receptor levels or virus binding, indicating that virus fusion is enhanced. The liposomes are easily generated, store well, and allow enhanced infection with a variety of virus vectors and cell types.
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Affiliation(s)
- David A Coil
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109-1024, USA
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36
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Duh FM, Dirks C, Lerman MI, Miller AD. Amino acid residues that are important for Hyal2 function as a receptor for jaagsiekte sheep retrovirus. Retrovirology 2005; 2:59. [PMID: 16191204 PMCID: PMC1262777 DOI: 10.1186/1742-4690-2-59] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2005] [Accepted: 09/28/2005] [Indexed: 02/06/2023] Open
Abstract
Background Infection by jaagsiekte sheep retrovirus (JSRV) and by enzootic nasal tumor virus (ENTV) depends on cell-surface expression of the virus entry receptor, hyaluronidase 2 (Hyal2). Human Hyal2 binds the envelope (Env) proteins of these viruses and is functional as a receptor, but Hyal2 from mice does not bind Env nor does it mediate entry of either virus. Here we have explored the amino acid determinants that account for the difference in receptor function. Results Analysis of human-mouse Hyal2 chimeric proteins showed that amino acid differences responsible for the difference in Hyal2 receptor activity were localized to the central third of Hyal2. Human Hyal2 mutants containing single or double amino acid replacements with the respective mouse amino acids were generated across this region and were assayed for activity. None of the single or double mutation reduced the receptor activity of human Hyal2 by more than 10-fold, whereas mouse Hyal2 activity is reduced 1,000-fold from that of human Hyal2. While the 3-dimensional structures of mammalian Hyal2 proteins are unknown, bee venom hyaluronidase shows significant amino acid similarity to human and mouse Hyal2 and its structure has been determined. Many mutations having the largest negative effects on human Hyal2 function mapped to a small region of the bee venom hyaluronidase close to but not overlapping the active site of the enzyme, suggesting that this site represents the binding site for Env. Analysis of synonymous and non-synonymous nucleotide substitutions in the coding sequences of multiple mammalian Hyal2 proteins shows that the proteins are undergoing strong selection for amino acid conservation. We found no evidence for positive selection of amino acid changes that might reflect evolution of mammalian hosts to resist JSRV or ENTV infection. Conclusion These results show that the greatly reduced receptor activity of mouse Hyal2 in comparison to that of human Hyal2 is determined by multiple amino acid changes acting in concert. In particular, no one amino acid change blocks infection. However, the most important amino acids map to a small patch on a predicted 3-dimensional Hyal2 structure, which may represent the binding site for Env.
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Affiliation(s)
- Fuh-Mei Duh
- Basic Research Program, SAIC-Frederick, National Cancer Institute at Frederick, Frederick, Maryland 21702, USA
- Laboratory of Immunobiology, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland 21702, USA
| | - Clarissa Dirks
- Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
- Current address: University of Washington, Seattle, Washington 98195, USA
| | - Michael I Lerman
- Laboratory of Immunobiology, Center for Cancer Research, National Cancer Institute at Frederick, Frederick, Maryland 21702, USA
| | - A Dusty Miller
- Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
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Sinn PL, Burnight ER, Shen H, Fan H, McCray PB. Inclusion of Jaagsiekte sheep retrovirus proviral elements markedly increases lentivirus vector pseudotyping efficiency. Mol Ther 2005; 11:460-9. [PMID: 15727943 DOI: 10.1016/j.ymthe.2004.10.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2004] [Revised: 10/11/2004] [Accepted: 10/26/2004] [Indexed: 11/23/2022] Open
Abstract
Retroviral pseudotyping for gene transfer applications endeavors to alter vector tropism and maintain a suitable titer. We investigated the compatibility of the Jaagsiekte sheep retrovirus (JSRV) envelope glycoprotein with the feline immunodeficiency virus (FIV) vector. A construct consisting of the minimal JSRV env coding region expressed from a standard mammalian expression plasmid generated FIV vector titers of approximately 10(4) TU/ml following standard triple transfection, collection of supernatants, and concentration by centrifuge. Interestingly, retention of the native proviral 5' and 3' flanking regions surrounding the JSRV env resulted in exceptional titers of approximately 10(8) TU/ml following the same viral preparation. To discern the regions necessary to achieve this 10,000-fold increase in titer, additional constructs were designed and tested. Our results indicate that the enhanced vector titer correlates with an increase in steady-state levels of envelope RNA that results from a combination of RNA splicing and stability, leading to increased envelope protein production. Expression of four other glycoproteins in an expression plasmid retaining the enhancing elements from the JSRV proviral sequence increased FIV vector titers from 0- to 100-fold. These novel data demonstrate that optimization of the envelope expression construct can profoundly influence titers for lentivirus vectors.
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Affiliation(s)
- Patrick L Sinn
- Department of Pediatrics, Program in Gene Therapy, Carver College of Medicine, The University of Iowa, Iowa City, IA 52242, USA
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38
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Wootton SK, Halbert CL, Miller AD. Sheep retrovirus structural protein induces lung tumours. Nature 2005; 434:904-7. [PMID: 15829964 PMCID: PMC1401489 DOI: 10.1038/nature03492] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2004] [Accepted: 02/22/2005] [Indexed: 11/09/2022]
Abstract
Jaagsiekte sheep retrovirus (JSRV) causes a contagious lung cancer in sheep and goats, with significant animal health and economic consequences. The host range of JSRV is in part limited by species-specific differences in the virus entry receptor, hyaluronidase 2 (Hyal2), which is not functional as a receptor in mice but is functional in humans. Sheep are immunotolerant of JSRV because of the expression of closely related endogenous retroviruses, which are not present in humans and most other species, and this may facilitate oncogenesis. Here we show that expression of the JSRV envelope (Env) protein alone in lungs of mice, by using a replication-incompetent adeno-associated virus vector, results in tumours with a bronchiolo-alveolar localization like those seen in sheep. Whereas lethal disease was observed in immunodeficient mice, tumour development was almost entirely blocked in immunocompetent mice. Our results provide a rare example of an oncogenic viral structural protein, show that interaction of the viral Env protein with the virus entry receptor Hyal2 is not required for tumorigenesis, and indicate that immune recognition of Env can protect against JSRV tumorigenesis.
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MESH Headings
- Animals
- Antibodies, Viral/immunology
- Antigens, Viral/genetics
- Antigens, Viral/immunology
- Antigens, Viral/metabolism
- Cell Transformation, Neoplastic
- Disease Models, Animal
- Gene Products, env/genetics
- Gene Products, env/immunology
- Gene Products, env/metabolism
- Genome, Viral
- Humans
- Jaagsiekte sheep retrovirus/genetics
- Jaagsiekte sheep retrovirus/immunology
- Jaagsiekte sheep retrovirus/metabolism
- Lung/pathology
- Lung/virology
- Lung Neoplasms/immunology
- Lung Neoplasms/pathology
- Lung Neoplasms/veterinary
- Lung Neoplasms/virology
- Mice
- Receptors, Virus/metabolism
- Sheep/virology
- Sheep Diseases/pathology
- Sheep Diseases/virology
- Species Specificity
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Affiliation(s)
- Sarah K Wootton
- Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, Washington 98109, USA
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39
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Sinn PL, Penisten AK, Burnight ER, Hickey MA, Williams G, McCoy DM, Mallampalli RK, McCray PB. Gene Transfer to Respiratory Epithelia with Lentivirus Pseudotyped with Jaagsiekte Sheep Retrovirus Envelope Glycoprotein. Hum Gene Ther 2005; 16:479-88. [PMID: 15871679 DOI: 10.1089/hum.2005.16.479] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A feline immunodeficiency virus (FIV)-based lentiviral vector was pseudotyped to identify envelope (env) glycoproteins that direct efficient gene transfer to pulmonary epithelia for the treatment or prevention of lung diseases. The envelope glycoprotein from the Jaagsiekte sheep retrovirus (JSRV) is a candidate under investigation. We utilized high titer FIV vector (>10(8) TU/ml) pseudotyped with the JSRV env glycoprotein (JSRVFIV) to study the transduction of polarized primary cultures of human airway epithelia and receptor/vector interactions. The reported receptor for JSRV, hyaluronidase 2 (HYAL2), is a GPI-linked protein. We expressed FLAG-tagged HYAL2 in polarized airway epithelia using an adenoviral vector and documented that the HYAL2 protein sorts predominantly to the apical surface. Of interest, the efficiency of gene transfer with apically applied JSRV-FIV was markedly less than FIV pseudotyped with VSV-G, even in Ad-HYAL2 complemented epithelia. The inefficient gene transfer with JSRV-FIV in HYAL2 complemented cells suggests that factors other than receptor abundance limit apical gene transfer efficiency with this envelope. JSRV-FIV transduced the distal lung epithelia of rabbits in vivo and transduced primary cultures of rabbit type II cells with 100-fold greater efficiency than primary cultures of rabbit tracheal cells. These data indicate that a lentivirus pseudotyped with the JSRV envelope glycoprotein transduces type II cells with greater efficiency than conducting airway epithelia and provides an example of glycoprotein-mediated cell-specific tropism within a tissue with a widely heterogeneous cell population.
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Affiliation(s)
- Patrick L Sinn
- Program in Gene Therapy, Department of Pediatrics, Carver College of Medicine, The University of Iowa, Iowa City, IA 52242, USA
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40
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Vigdorovich V, Strong RK, Miller AD. Expression and characterization of a soluble, active form of the jaagsiekte sheep retrovirus receptor, Hyal2. J Virol 2005; 79:79-86. [PMID: 15596803 PMCID: PMC538683 DOI: 10.1128/jvi.79.1.79-86.2005] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Retrovirus entry into cells is mediated by specific interactions between virus envelope glycoproteins and cell surface receptors. Many of these receptors contain multiple membrane-spanning regions, making their purification and study difficult. The jaagsiekte sheep retrovirus (JSRV) receptor, hyaluronidase 2 (Hyal2), is a glycosylphosphatidylinositol (GPI)-anchored molecule containing no peptide transmembrane regions, making it an attractive candidate for study of retrovirus entry. Further, the hyaluronidase activity reported for human Hyal2, combined with its broad expression pattern, may point to a critical function of Hyal2 in the turnover of hyaluronan, a major extracellular matrix component. Here we describe the properties of a soluble form of human Hyal2 (sHyal2) purified from a baculoviral expression system. sHyal2 is a 54-kDa monomer with weak hyaluronidase activity compared to that of the known hyaluronidase Spam1. In contrast to a previous report indicating that Hyal2 cleaved hyaluronan to a limit product of 20 kDa and was active only at acidic pH, we find that sHyal2 is capable of further degradation of hyaluronan and is active over a broad pH range, consistent with Hyal2 being active at the cell surface where it is normally localized. Interaction of sHyal2 with the JSRV envelope glycoprotein was analyzed by viral inhibition assays, showing >90% inhibition of transduction at 28 nM sHyal2, and by surface plasmon resonance, revealing a remarkably tight specific interaction with a dissociation constant (KD) of 32 +/- 1 pM. In contrast to results obtained with avian retroviruses, purified receptor was not capable of promoting transduction of cells that do not express the virus receptor.
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Affiliation(s)
- Vladimir Vigdorovich
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109-1024, USA
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41
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Van Hoeven NS, Miller AD. Improved enzootic nasal tumor virus pseudotype packaging cell lines reveal virus entry requirements in addition to the primary receptor Hyal2. J Virol 2005; 79:87-94. [PMID: 15596804 PMCID: PMC538734 DOI: 10.1128/jvi.79.1.87-94.2005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2004] [Accepted: 08/26/2004] [Indexed: 11/20/2022] Open
Abstract
Enzootic nasal tumor virus (ENTV) and jaagsiekte sheep retrovirus (JSRV) are closely related retroviruses that cause epithelial cancers of the respiratory tract in sheep and goats. Both viruses use the glycosylphosphatidylinositol (GPI)-anchored cell surface protein hyaluronidase 2 (Hyal2) as a receptor for cell entry, and entry is mediated by the envelope (Env) proteins encoded by these viruses. Retroviral vectors bearing JSRV Env can transduce cells from a wide range of species, with the exception of rodent cells. Because of the low titer of vectors bearing ENTV Env, it has been difficult to determine the tropism of ENTV vectors, which appeared to transduce cells from sheep and humans only. Here we have developed high-titer ENTV packaging cells and confirm that ENTV has a restricted host range compared to that of JSRV. Most cells that are not transduced by JSRV or ENTV vectors can be made susceptible following expression of human Hyal2 on the cells. However, five rat cell lines from different rat strains and different tissues that were engineered to express human Hyal2 were still only poorly infected by ENTV vectors, even though the ENTV Env protein could bind well to human Hyal2 expressed on four of these cell lines. These results indicate the possibility of a coreceptor requirement for these viruses.
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Affiliation(s)
- Neal S Van Hoeven
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109-1024, USA
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42
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Liu SL, Miller AD. Transformation of madin-darby canine kidney epithelial cells by sheep retrovirus envelope proteins. J Virol 2005; 79:927-33. [PMID: 15613321 PMCID: PMC538587 DOI: 10.1128/jvi.79.2.927-933.2005] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2004] [Accepted: 08/26/2004] [Indexed: 11/20/2022] Open
Abstract
Jaagsiekte sheep retrovirus (JSRV) and enzootic nasal tumor virus (ENTV) induce epithelial tumors in the airways of sheep and goats. In both of these simple retroviruses, the envelope (Env) protein is the active oncogene. Furthermore, JSRV Env can transform cultured cells by two distinct mechanisms. In rat and mouse fibroblasts, the cytoplasmic tail of JSRV Env is essential for transformation, which involves activation of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway, and the virus receptor hyaluronidase 2 (Hyal2) is not involved. In contrast, in the BEAS-2B human bronchial epithelial cell line, transformation is mediated by JSRV Env binding to Hyal2 followed by Hyal2 degradation and activation of the receptor tyrosine kinase RON, the activity of which is normally suppressed by Hyal2. Here we show that JSRV and ENTV Env proteins can also transform Madin-Darby canine kidney (MDCK) epithelial cells, but by a mechanism similar to that observed in fibroblast cell lines. In particular, the cytoplasmic tail of Env is required for transformation, the PI3K/Akt pathway is activated, expression of RON (which is not normally expressed in MDCK cells) does not affect transformation, and canine Hyal2 appears uninvolved. These results show that the JSRV and ENTV Env proteins can transform epithelial cells besides BEAS-2B cells and argue against a model for Env transformation involving different pathways that are uniquely active in fibroblasts or epithelial cells.
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Affiliation(s)
- Shan-Lu Liu
- Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N., Room C2-105, Seattle, WA 98109-1024, USA
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Hofacre A, Fan H. Multiple domains of the Jaagsiekte sheep retrovirus envelope protein are required for transformation of rodent fibroblasts. J Virol 2004; 78:10479-89. [PMID: 15367614 PMCID: PMC516437 DOI: 10.1128/jvi.78.19.10479-10489.2004] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Jaagsiekte sheep retrovirus (JSRV) is an exogenous retrovirus of sheep that induces a contagious lung cancer, ovine pulmonary adenocarcinoma. We previously showed that the gene encoding JSRV envelope protein (Env) appears to function as an oncogene, since it can transform mouse NIH 3T3 cells. The cytoplasmic tail of the Env transmembrane protein (TM) is necessary for the transformation. However, previous experiments did not exclude the involvement of the Env surface protein (SU) in transformation. In this study, we created a series of nested deletion mutants through the SU domain and assessed their ability to transform rodent fibroblasts. All SU deletion mutants downstream of the predicted signal peptide were unable to transform murine NIH 3T3 or rat 208F cells. Transport to the plasma membrane of selected deleted Env proteins was confirmed by confocal immunofluorescence microscopy of hemagglutinin-tagged versions. Additional sequential SU deletion mutants lacking 50-amino-acid (aa) blocks throughout SU also were unable to transform. Furthermore, minimal insertion mutants of two amino acids (Leu/Gln) at various positions in SU also abolished transformation. These data indicate that domains in SU facilitate efficient JSRV transformation. This could reflect a necessity of SU for appropriate configuration of the Env protein or independent activation by SU of a signaling pathway necessary for transformation. Complementation between SU and TM mutants for transformation supported the latter hypothesis. Cotransfection with DeltaGP Y590F (mutant in the TM cytoplasmic tail) with DeltaGP SUDelta103-352 (lacking most of SU) resulted in efficient transformation. The resulting transformants showed evidence for the presence and expression of both mutant plasmids.
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Affiliation(s)
- Andrew Hofacre
- Cancer Research Institute, Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, CA 92697-3905, USA
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Miller AD, Van Hoeven NS, Liu SL. Transformation and scattering activities of the receptor tyrosine kinase RON/Stk in rodent fibroblasts and lack of regulation by the jaagsiekte sheep retrovirus receptor, Hyal2. BMC Cancer 2004; 4:64. [PMID: 15363108 PMCID: PMC521489 DOI: 10.1186/1471-2407-4-64] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2004] [Accepted: 09/13/2004] [Indexed: 12/13/2022] Open
Abstract
Background The envelope (Env) protein of jaagsiekte sheep retrovirus (JSRV) can transform cells in culture and is likely to be the main factor responsible for lung cancer induction by JSRV in animals. A recent report indicates that the epithelial-cell transforming activity of JSRV Env depends on activation of the cell-surface receptor tyrosine kinase Mst1r (called RON for the human and Stk for the rodent orthologs). In the immortalized line of human epithelial cells used (BEAS-2B cells), the virus receptor Hyal2 was found to bind to and suppress the activity of RON. When Env was expressed it bound to Hyal2 causing its degradation, release of RON activity from Hyal2 suppression, and activation of pathways resulting in cell transformation. Methods Due to difficulty with reproducibility of the transformation assay in BEAS-2B cells, we have used more tractable rodent fibroblast models to further study Hyal2 modulation of RON/Stk transforming activity and potential effects of Hyal2 on RON/Stk activation by its natural ligand, macrophage stimulating protein (MSP). Results We did not detect transformation of NIH 3T3 cells by plasmids expressing RON or Stk, but did detect transformation of 208F rat fibroblasts by these plasmids at a very low rate. We were able to isolate 208F cell clones that expressed RON or Stk and that showed changes in morphology indicative of transformation. The parental 208F cells did not respond to MSP but 208F cells expressing RON or Stk showed obvious increases in scattering/transformation in response to MSP. Human Hyal2 had no effect on the basal or MSP-induced phenotypes of RON-expressing 208F cells, and human, mouse or rat Hyal2 had no effect on the basal or MSP-induced phenotypes of Stk-expressing 208F cells. Conclusions We have shown that RON or Stk expression in 208F rat fibroblasts results in a transformed phenotype that is enhanced by addition of the natural ligand for these proteins, MSP. Hyal2 does not directly modulate the basal or MSP-induced RON/Stk activity, although it is possible that adaptor proteins might mediate such signaling in other cell types.
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Affiliation(s)
- A Dusty Miller
- Division of Human Biology, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109-1024, USA
| | - Neal S Van Hoeven
- Division of Human Biology, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109-1024, USA
- Molecular and Cellular Biology Program, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109-1024, USA
| | - Shan-Lu Liu
- Division of Human Biology, Fred Hutchinson Cancer Research Center, 1100 Fairview Avenue North, Seattle, WA 98109-1024, USA
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Palmarini M, Mura M, Spencer TE. Endogenous betaretroviruses of sheep: teaching new lessons in retroviral interference and adaptation. J Gen Virol 2004; 85:1-13. [PMID: 14718613 DOI: 10.1099/vir.0.19547-0] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The endogenous betaretroviruses of small ruminants offer an excellent model to investigate the biological relevance of endogenous retroviruses (ERVs). Approximately twenty copies of endogenous betaretroviruses (enJSRVs) are present in the genome of sheep and goats. enJSRVs are highly related to Jaagsiekte sheep retrovirus (JSRV) and the Enzootic nasal tumour virus (ENTV), the causative agents of naturally occurring carcinomas of the respiratory tract of sheep. enJSRVs interact/interfere at different levels both with the host and with their exogenous and pathogenic counterparts. enJSRVs blocks the exogenous JSRV replication by a novel two-step interference mechanism acting both early and late during the virus replication cycle. enJSRVs are highly active, they are abundantly and specifically expressed in the epithelium of most of the ovine female reproductive tract. The specific spatial and temporal expression of enJSRVs supports a role in trophoblast development and differentiation as well as conceptus implantation. In addition, enJSRVs are expressed during fetal ontogeny leading to the apparent tolerance of sheep towards the pathogenic JSRV. Thus, the sheep/enJSRVs system is a model that can be utilized to study many different aspects of ERVs and retrovirus biology. The impressive technologies developed to study the sheep reproductive biology, in conjunction with the knowledge gained on the molecular biology of enJSRVs, makes the ovine system an ideal model to design experiments that can functionally address the role of ERVs in mammalian physiology.
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Affiliation(s)
- Massimo Palmarini
- Department of Medical Microbiology and Parasitology, College of Veterinary Medicine, The University of Georgia, Athens, GA 30602, USA
| | - Manuela Mura
- Department of Medical Microbiology and Parasitology, College of Veterinary Medicine, The University of Georgia, Athens, GA 30602, USA
| | - Thomas E Spencer
- Center for Animal Biotechnology and Genomics, and Department of Animal Science, Texas A&M University, College Station, TX 77843, USA
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Liu SL, Halbert CL, Miller AD. Jaagsiekte sheep retrovirus envelope efficiently pseudotypes human immunodeficiency virus type 1-based lentiviral vectors. J Virol 2004; 78:2642-7. [PMID: 14963173 PMCID: PMC369219 DOI: 10.1128/jvi.78.5.2642-2647.2003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2003] [Accepted: 11/13/2003] [Indexed: 01/28/2023] Open
Abstract
Jaagsiekte sheep retrovirus (JSRV) infects lung epithelial cells in sheep, and oncoretroviral vectors bearing JSRV Env can mediate transduction of human cells, suggesting that such vectors might be useful for lung-directed gene therapy. Here we show that JSRV Env can also efficiently pseudotype a human immunodeficiency virus type 1-based lentiviral vector, a more suitable vector for transduction of slowly dividing lung epithelial cells. We created several chimeric Env proteins that, unlike the parental Env, do not transform rodent fibroblasts but are still capable of pseudotyping lentiviral and oncoretroviral vectors.
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Affiliation(s)
- Shan-Lu Liu
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
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Abstract
Endogenous retrovirus (ERV) sequences have been found in all mammals. In vitro and in vivo experiments revealed ERV activation and cross-species infection in several species. Sheep (Ovis aries) are used for various biotechnological purposes; however, they have not yet been comprehensively screened for ERV sequences. Therefore, the aim of the study was to classify the ERV sequences in the ovine genome (OERV) by analyzing the retroviral pro-pol sequences. Three OERV beta families and nine OERV gamma families were revealed. Novel open reading frames (ORF) in the amplified proviral fragment were found in one OERV beta family and two OERV gamma families. Hybrid OERV produced by putative recombination events were not detected. Quantitative analysis of the OERV sequences in the ovine genome revealed no relevant variations in the endogenous retroviral loads of different breeds. Expression analysis of different tissues from fetal and pregnant sheep detected mRNA from both gammaretrovirus families, showing ORF fragments. Thus, the release of retroviruses from sheep cells cannot be excluded.
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Maeda N, Inoshima Y, Fruman DA, Brachmann SM, Fan H. Transformation of mouse fibroblasts by Jaagsiekte sheep retrovirus envelope does not require phosphatidylinositol 3-kinase. J Virol 2003; 77:9951-9. [PMID: 12941905 PMCID: PMC224593 DOI: 10.1128/jvi.77.18.9951-9959.2003] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Jaagsiekte sheep retrovirus (JSRV) is the causative agent of ovine pulmonary adenocarcinoma, a transmissible lung cancer of sheep. The envelope of JSRV may have oncogenic properties, since it can morphologically transform mouse NIH 3T3 cells and other fibroblast lines. Recently, we found that the cytoplasmic tail of the envelope transmembrane (TM) protein is necessary for transformation, and in particular a consensus binding motif (YXXM) for phosphatidylinositol 3-kinase (PI3K) is important. Moreover, JSRV-transformed cells show phosphorylation (activation) of Akt/protein kinase B, a downstream target of PI3K. In these studies, we directly tested for the involvement of PI3K in transformation by JSRV. Contrary to expectations, four different experiments indicated that PI3K is not necessary for JSRV-induced transformation: (i) cotransfection with a dominant negative truncated form of the PI3K regulatory subunit (Deltap85) did not affect transformation frequency, (ii) cells stably expressing Deltap85 showed the same frequencies of transformation as parental NIH 3T3 cells, (iii) fibroblasts established from double-knockout mice lacking PI3K p85alpha and p85beta could be transformed with JSRV envelope, and (iv) incubation of cells with the PI3K inhibitor LY294002 did not specifically inhibit transformation, nor did the drug reverse transformation of JSRV-transformed cells. One alternate explanation for the lack of transformation by YXXM mutants could be that they were defective in intracellular trafficking. However, confocal microscopy of epitope-tagged envelope proteins of both wild-type and nontransforming YXXM mutants showed a cell surface or plasma membrane localization. While PI3K is not required for JSRV-induced transformation of NIH 3T3 cells, the downstream target Akt kinase was found to be activated (phosphorylated) in JSRV-transformed PI3K-negative cells. Therefore, JSRV envelope can induce PI3K-independent phosphorylation of Akt.
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Affiliation(s)
- Naoyoshi Maeda
- Cancer Research Institute, University of California-Irvine, Irvine, CA 92697-3000, USA
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Zavala G, Pretto C, Chow YHJ, Jones L, Alberti A, Grego E, De las Heras M, Palmarini M. Relevance of Akt phosphorylation in cell transformation induced by Jaagsiekte sheep retrovirus. Virology 2003; 312:95-105. [PMID: 12890624 DOI: 10.1016/s0042-6822(03)00205-8] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Expression of the JSRV envelope (Env) is sufficient to transform immortalized rodent fibroblasts. A putative docking site for the PI3-K kinase (Y(590)-X-X-M(593)) in the cytoplasmic tail of the transmembrane domain of the JSRV Env is a major determinant of viral-induced cell transformation. Akt is constitutively phosphorylated in rodent fibroblasts transformed by the JSRV Env. However, recent data suggest that Y590 and M593 are not necessary for JSRV Env-induced transformation of the immortalized chicken fibroblasts cell line DF-1. In this study we found that JSRV-induced transformation of DF-1 cells is Akt-independent. In addition, a replication-competent avian vector expressing the JSRV Env (RCASBP(A)+JE) was also able to induce transformation of primary chicken embryo fibroblasts (CEF). Vectors expressing JSRV Env Y590 mutants were still able to induce CEF cells transformation but not as efficiently as the vectors expressing the wild-type Env. In CEF cells, as in DF-1 cells, only the expression of the wild-type Env induced constitutive phosphorylation of Akt. Thus, in chicken cells, the degree of transformation induced by the JSRV Env is maximum in the presence of Y590 and Akt phosphorylation. We addressed the significance of Akt phosphorylation in rat 208F cells transformed by the JSRV Env and showed that Akt is indeed activated and shows kinase activity. Inhibitors of the PI-3K/Akt pathway reproducibly decreased the transformation efficiency of the JSRV Env. In vivo, we found phosphorylated Akt only in nasal tumors induced by the enzootic nasal tumor virus (ENTV), a JSRV-related beta-retrovirus. No evidence of Akt phosphorylation was found in lung tumor sections of sheep affected by pulmonary adenocarcinoma. As a whole, these results suggest that the activation of the PI-3K/Akt pathway contributes to the process of JSRV-induced cell transformation but most likely is not the primary determinant both in vitro and in vivo.
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Affiliation(s)
- Guillermo Zavala
- Department of Medical Microbiology and Parasitology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA
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Chow YHJ, Alberti A, Mura M, Pretto C, Murcia P, Albritton LM, Palmarini M. Transformation of rodent fibroblasts by the jaagsiekte sheep retrovirus envelope is receptor independent and does not require the surface domain. J Virol 2003; 77:6341-50. [PMID: 12743291 PMCID: PMC155026 DOI: 10.1128/jvi.77.11.6341-6350.2003] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Jaagsiekte sheep retrovirus (JSRV) is the etiological agent of a contagious lung cancer of sheep known as ovine pulmonary adenocarcinoma (OPA). Expression of the JSRV envelope protein (Env) is sufficient to transform immortalized and primary fibroblasts, but the precise mechanisms of this process are not known. The cellular receptor for JSRV is hyaluronidase 2 (Hyal-2), the product of a putative tumor suppressor gene that in humans maps to a chromosomal region frequently deleted in the development of lung and breast cancers. Here we report studies to determine whether the Hyal-2-JSRV Env interaction plays a role in virus-induced transformation of rodent fibroblasts. Chimeric Env proteins between JSRV and the unrelated murine retroviruses Moloney murine leukemia virus (MMuLV) and mouse mammary tumor virus (MMTV) showed cell surface expression comparable to that of wild-type MMuLV Env and rescued infection of MMuLV particle pseudotypes. Interestingly, an MMuLV-JSRV chimera in which the putative receptor binding domain (RBD) and proline-rich region (PRR) of JSRV Env were replaced by the RBD and PRR of MMuLV induced transformation of 208F, a rodent fibroblast line. Cell lines derived from foci of MMuLV-JSRV chimera-transformed 208F cells grew in soft agar and showed Akt activation, a hallmark of JSRV-transformed rodent fibroblasts. Transformation assays performed using proteins with amino-terminal deletion mutations showed that the carboxy-terminal 141 amino acids of the transmembrane subunit (TM) were sufficient to induce cell transformation when targeted to the membrane with a myristoylation signal. Thus, the JSRV TM is necessary and sufficient to transform rodent fibroblasts. Taken together these results indicate that the interaction with Hyal-2 at least is not an essential determinant of JSRV-induced transformation of fibroblasts and that the viral TM functions essentially as an oncoprotein.
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Affiliation(s)
- Yen-Hung J Chow
- Department of Medical Microbiology and Parasitology and Comparative Oncology Program, College of Veterinary Medicine, University of Georgia, Athens 30602, USA
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