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Dang DD, Rosenblum JS, Shah AH, Zhuang Z, Doucet-O’Hare TT. Epigenetic Regulation in Primary CNS Tumors: An Opportunity to Bridge Old and New WHO Classifications. Cancers (Basel) 2023; 15:2511. [PMID: 37173979 PMCID: PMC10177493 DOI: 10.3390/cancers15092511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 04/22/2023] [Accepted: 04/25/2023] [Indexed: 05/15/2023] Open
Abstract
Originally approved in 1979, a specific grading classification for central nervous system (CNS) tumors was devised by the World Health Organization (WHO) in an effort to guide cancer treatment and better understand prognosis. These "blue books" have since undergone several iterations based on tumor location, advancements in histopathology, and most recently, diagnostic molecular pathology in its fifth edition. As new research methods have evolved to elucidate complex molecular mechanisms of tumorigenesis, a need to update and integrate these findings into the WHO grading scheme has become apparent. Epigenetic tools represent an area of burgeoning interest that encompasses all non-Mendelian inherited genetic features affecting gene expression, including but not limited to chromatin remodeling complexes, DNA methylation, and histone regulating enzymes. The SWItch/Sucrose non-fermenting (SWI/SNF) chromatin remodeling complex is the largest mammalian family of chromatin remodeling proteins and is estimated to be altered in 20-25% of all human malignancies; however, the ways in which it contributes to tumorigenesis are not fully understood. We recently discovered that CNS tumors with SWI/SNF mutations have revealed an oncogenic role for endogenous retroviruses (ERVs), remnants of exogenous retroviruses that integrated into the germline and are inherited like Mendelian genes, several of which retain open reading frames for proteins whose expression putatively contributes to tumor formation. Herein, we analyzed the latest WHO classification scheme for all CNS tumors with documented SWI/SNF mutations and/or aberrant ERV expression, and we summarize this information to highlight potential research opportunities that could be integrated into the grading scheme to better delineate diagnostic criteria and therapeutic targets.
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Affiliation(s)
- Danielle D. Dang
- Neuro-Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jared S. Rosenblum
- Neuro-Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ashish H. Shah
- Section of Virology and Immunotherapy, Department of Neurosurgery, Leonard M. Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Zhengping Zhuang
- Neuro-Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Tara T. Doucet-O’Hare
- Neuro-Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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Abstract
Retroviruses infect a broad range of vertebrate hosts that includes amphibians, reptiles, fish, birds and mammals. In addition, a typical vertebrate genome contains thousands of loci composed of ancient retroviral sequences known as endogenous retroviruses (ERVs). ERVs are molecular remnants of ancient retroviruses and proof that the ongoing relationship between retroviruses and their vertebrate hosts began hundreds of millions of years ago. The long-term impact of retroviruses on vertebrate evolution is twofold: first, as with other viruses, retroviruses act as agents of selection, driving the evolution of host genes that block viral infection or that mitigate pathogenesis, and second, through the phenomenon of endogenization, retroviruses contribute an abundance of genetic novelty to host genomes, including unique protein-coding genes and cis-acting regulatory elements. This Review describes ERV origins, their diversity and their relationships to retroviruses and discusses the potential for ERVs to reveal virus-host interactions on evolutionary timescales. It also describes some of the many examples of cellular functions, including protein-coding genes and regulatory elements, that have evolved from ERVs.
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Li M, Radvanyi L, Yin B, Rycaj K, Li J, Chivukula R, Lin K, Lu Y, Shen J, Chang DZ, Li D, Johanning GL, Wang-Johanning F. Downregulation of Human Endogenous Retrovirus Type K (HERV-K) Viral env RNA in Pancreatic Cancer Cells Decreases Cell Proliferation and Tumor Growth. Clin Cancer Res 2017; 23:5892-5911. [PMID: 28679769 DOI: 10.1158/1078-0432.ccr-17-0001] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 05/09/2017] [Accepted: 06/29/2017] [Indexed: 12/23/2022]
Abstract
Purpose: We investigated the role of the human endogenous retrovirus type K (HERV-K) envelope (env) gene in pancreatic cancer.Experimental Design: shRNA was employed to knockdown (KD) the expression of HERV-K in pancreatic cancer cells.Results: HERV-K env expression was detected in seven pancreatic cancer cell lines and in 80% of pancreatic cancer patient biopsies, but not in two normal pancreatic cell lines or uninvolved normal tissues. A new HERV-K splice variant was discovered in several pancreatic cancer cell lines. Reverse transcriptase activity and virus-like particles were observed in culture media supernatant obtained from Panc-1 and Panc-2 cells. HERV-K viral RNA levels and anti-HERV-K antibody titers were significantly higher in pancreatic cancer patient sera (N = 106) than in normal donor sera (N = 40). Importantly, the in vitro and in vivo growth rates of three pancreatic cancer cell lines were significantly reduced after HERV-K KD by shRNA targeting HERV-K env, and there was reduced metastasis to lung after treatment. RNA-Seq results revealed changes in gene expression after HERV-K env KD, including RAS and TP53. Furthermore, downregulation of HERV-K Env protein expression by shRNA also resulted in decreased expression of RAS, p-ERK, p-RSK, and p-AKT in several pancreatic cancer cells or tumors.Conclusions: These results demonstrate that HERV-K influences signal transduction via the RAS-ERK-RSK pathway in pancreatic cancer. Our data highlight the potentially important role of HERV-K in tumorigenesis and progression of pancreatic cancer, and indicate that HERV-K viral proteins may be attractive biomarkers and/or tumor-associated antigens, as well as potentially useful targets for detection, diagnosis, and immunotherapy of pancreatic cancer. Clin Cancer Res; 23(19); 5892-911. ©2017 AACR.
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Affiliation(s)
- Ming Li
- Viral Oncology Program, Center for Cancer and Metabolism, SRI International, Menlo Park, California
| | - Laszlo Radvanyi
- EMD Serono Research and Development Institute, Billerica, Massachusetts
| | - Bingnan Yin
- Department of Inflammation and Epigenetics, Methodist Research Institute, Houston, Texas
| | | | - Jia Li
- Viral Oncology Program, Center for Cancer and Metabolism, SRI International, Menlo Park, California
| | - Raghavender Chivukula
- Viral Oncology Program, Center for Cancer and Metabolism, SRI International, Menlo Park, California
| | - Kevin Lin
- Department of Epigenetics and Molecular Carcinogenesis, Science Park, the University of Texas MD Anderson Cancer Center, Smithville, Texas
| | - Yue Lu
- Department of Epigenetics and Molecular Carcinogenesis, Science Park, the University of Texas MD Anderson Cancer Center, Smithville, Texas
| | - JianJun Shen
- Department of Epigenetics and Molecular Carcinogenesis, Science Park, the University of Texas MD Anderson Cancer Center, Smithville, Texas
| | - David Z Chang
- Virginia Oncology Associates, Newport News, Virginia
| | - Donghui Li
- Department of Gastrointestinal Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Gary L Johanning
- Viral Oncology Program, Center for Cancer and Metabolism, SRI International, Menlo Park, California
| | - Feng Wang-Johanning
- Viral Oncology Program, Center for Cancer and Metabolism, SRI International, Menlo Park, California.
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Monde K, Terasawa H, Nakano Y, Soheilian F, Nagashima K, Maeda Y, Ono A. Molecular mechanisms by which HERV-K Gag interferes with HIV-1 Gag assembly and particle infectivity. Retrovirology 2017; 14:27. [PMID: 28446240 PMCID: PMC5406883 DOI: 10.1186/s12977-017-0351-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 04/18/2017] [Indexed: 02/07/2023] Open
Abstract
Background Human endogenous retroviruses (HERVs), the remnants of ancient retroviral infections, constitute approximately 8% of human genomic DNA. Since HERV-K Gag expression is induced by HIV-1 Tat in T cells, induced HERV-K proteins could affect HIV-1 replication. Indeed, previously we showed that HERV-K Gag and HIV-1 Gag coassemble and that this appears to correlate with the effect of HERV-K Gag expression on HIV-1 particle release and its infectivity. We further showed that coassembly requires both MA and NC domains, which presumably serve as scaffolding for Gag via their abilities to bind membrane and RNA, respectively. Notably, however, despite possessing these abilities, MLV Gag failed to coassemble with HIV-1 Gag and did not affect assembly and infectivity of HIV-1 particles. It is unclear how the specificity of coassembly is determined. Results Here, we showed that coexpression of HERV-K Gag with HIV-1 Gag changed size and morphology of progeny HIV-1 particles and severely diminished infectivity of such progeny viruses. We further compared HERV-K-MLV chimeric constructs to identify molecular determinants for coassembly specificity and for inhibition of HIV-1 release efficiency and infectivity. We found that the CA N-terminal domain (NTD) of HERV-K Gag is important for the reduction of the HIV-1 release efficiency, whereas both CA-NTD and major homology region of HERV-K Gag contribute to colocalization with HIV-1 Gag. Interestingly, these regions of HERV-K Gag were not required for reduction of progeny HIV-1 infectivity. Conclusions Our results showed that HERV-K Gag CA is important for reduction of HIV-1 release and infectivity but the different regions within CA are involved in the effects on the HIV-1 release and infectivity. Altogether, these findings revealed that HERV-K Gag interferes the HIV-1 replication by two distinct molecular mechanisms. Electronic supplementary material The online version of this article (doi:10.1186/s12977-017-0351-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kazuaki Monde
- Department of Medical Virology, Graduate School of Medical Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan. .,Department of Microbiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.
| | - Hiromi Terasawa
- Department of Medical Virology, Graduate School of Medical Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.,Department of Microbiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Yusuke Nakano
- Department of Medical Virology, Graduate School of Medical Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.,Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto, Japan
| | - Ferri Soheilian
- Electron Microscopy Laboratory, Leidos Biomedical Research, Inc, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Kunio Nagashima
- Electron Microscopy Laboratory, Leidos Biomedical Research, Inc, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Yosuke Maeda
- Department of Medical Virology, Graduate School of Medical Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan.,Department of Microbiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Akira Ono
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, USA
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Johanning GL, Malouf GG, Zheng X, Esteva FJ, Weinstein JN, Wang-Johanning F, Su X. Expression of human endogenous retrovirus-K is strongly associated with the basal-like breast cancer phenotype. Sci Rep 2017; 7:41960. [PMID: 28165048 PMCID: PMC5292751 DOI: 10.1038/srep41960] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 01/03/2017] [Indexed: 12/18/2022] Open
Abstract
Human endogenous retroviruses (HERVs), which make up approximately 8% of the human genome, are overexpressed in some breast cancer cells and tissues but without regard to cancer subtype. We, therefore, analyzed TCGA RNA-Seq data to evaluate differences in expression of the HERV-K family in breast cancers of the various subtypes. Four HERV-K loci on different chromosomes were analyzed in basal, Her2E, LumA, and LumB breast cancer subtypes of 512 breast cancer patients with invasive ductal carcinoma (IDC). The results for all four loci showed higher HERV-K expression in the basal subtype, suggesting similar mechanisms of regulation regardless of locus. Expression of the HERV-K envelope gene (env) was highly significantly increased in basal tumors in comparison with the also-upregulated expression of other HERV-K genes. Analysis of reverse-phase protein array data indicated that increased expression of HERV-K is associated with decreased mutation of H-Ras (wild-type). Our results show elevation of HERV-K expression exclusively in the basal subtype of IDC breast cancer (as opposed to the other subtypes) and suggest HERV-K as a possible target for cancer vaccines or immunotherapy against this highly aggressive form of breast cancer.
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Affiliation(s)
- Gary L Johanning
- SRI International, Biosciences Division, 333 Ravenswood Ave, Menlo Park, CA, USA
| | - Gabriel G Malouf
- Department of Medical Oncology, Groupe Hospitalier Pitié-Salpêtrière, Université Pierre and Marie Curie (Paris VI), GRC5, ONCOTYPE-Uro, Institut Universitaire de Cancérologie, Assistance-Publique Hôpitaux de Paris, Paris, France
| | - Xiaofeng Zheng
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Francisco J Esteva
- Laura and Isaac Perlmutter Cancer Center, New York University Langone Medical Center, New York, NY, USA
| | - John N Weinstein
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.,Department of Systems Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Feng Wang-Johanning
- SRI International, Biosciences Division, 333 Ravenswood Ave, Menlo Park, CA, USA
| | - Xiaoping Su
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
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Contreras-Galindo R, Kaplan MH, Dube D, Gonzalez-Hernandez MJ, Chan S, Meng F, Dai M, Omenn GS, Gitlin SD, Markovitz DM. Human Endogenous Retrovirus Type K (HERV-K) Particles Package and Transmit HERV-K-Related Sequences. J Virol 2015; 89:7187-201. [PMID: 25926654 PMCID: PMC4473553 DOI: 10.1128/jvi.00544-15] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 04/25/2015] [Indexed: 01/01/2023] Open
Abstract
UNLABELLED Human endogenous retroviruses (HERV) make up 8% of the human genome. While the youngest of these retroviruses, HERV-K(HML-2), termed HK2, is able to code for all viral proteins and produce virus-like particles, it is not known if these virus particles package and transmit HK2-related sequences. Here, we analyzed the capacity of HK2 for packaging and transmitting HK2 sequences. We created an HK2 probe, termed Bogota, which can be packaged into HK2 viruses, and transfected it into cells that make HK2 particles. Supernatants of the transfected cells, which contained HK2 viral particles, then were added to target cells, and the transmissibility of the HK2 Bogota reporter was tracked by G418 resistance. Our studies revealed that contemporary HK2 virions produced by some teratocarcinoma and breast cancer cell lines, as well as by peripheral blood lymphocytes from lymphoma patients, can package HK2 Bogota probes, and these viruses transmitted these probes to other cells. After transmission, HK2 Bogota transcripts undergo reverse transcription, a step impaired by antiretroviral agents or by introduction of mutations into the probe sequences required for reverse transcription. HK2 viruses were more efficiently transmitted in the presence of HK2 Rec or HIV-1 Tat and Vif. Transmitted Bogota probes formed episomes but did not integrate into the cellular genome. Resistance to integration might explain the relatively low number of HK2 insertions that were acquired during the last 25 million years of evolution. Whether transient transmission of modern HK2 sequences, which encode two putative oncoproteins, can lead to disease remains to be studied. IMPORTANCE Retroviruses invaded the genome of human ancestors over the course of millions of years, yet these viruses generally have been inactivated during evolution, with only remnants of these infectious sequences remaining in the human genome. One of these viruses, termed HK2, still is capable of producing virus particles, although these particles have been regarded as being noninfectious. Using a genetic probe derived from HK2, we have discovered that HK2 viruses produced in modern humans can package HK2 sequences and transmit them to various other cells. Furthermore, the genetic sequences packaged in HK2 undergo reverse transcription. The transmitted probe circularized in the cell and failed to integrate into the cellular genome. These findings suggest that modern HK2 viruses can package viral RNA and transmit it to other cells. Contrary to previous views, we provide evidence of an extracellular viral phase of modern HK2 viruses. We have no evidence of sustained, spreading infection.
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Affiliation(s)
| | - Mark H Kaplan
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Derek Dube
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Marta J Gonzalez-Hernandez
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA Programs in Immunology, University of Michigan, Ann Arbor, Michigan, USA
| | - Susana Chan
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Fan Meng
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, Michigan, USA Department of Psychiatry, University of Michigan, Ann Arbor, Michigan, USA
| | - Manhong Dai
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, Michigan, USA
| | - Gilbert S Omenn
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan, USA Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, USA Comprehensive Cancer Center, University of Michigan, Ann Arbor, Michigan, USA
| | - Scott D Gitlin
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA Comprehensive Cancer Center, University of Michigan, Ann Arbor, Michigan, USA Veteran Affairs Health System, Ann Arbor, Michigan, USA
| | - David M Markovitz
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA Programs in Immunology, University of Michigan, Ann Arbor, Michigan, USA Programs in Cancer Biology, University of Michigan, Ann Arbor, Michigan, USA Programs in Cellular and Molecular Biology, University of Michigan, Ann Arbor, Michigan, USA
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8
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Vincendeau M, Göttesdorfer I, Schreml JMH, Wetie AGN, Mayer J, Greenwood AD, Helfer M, Kramer S, Seifarth W, Hadian K, Brack-Werner R, Leib-Mösch C. Modulation of human endogenous retrovirus (HERV) transcription during persistent and de novo HIV-1 infection. Retrovirology 2015; 12:27. [PMID: 25886562 PMCID: PMC4375885 DOI: 10.1186/s12977-015-0156-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 03/05/2015] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND The human genome contains multiple LTR elements including human endogenous retroviruses (HERVs) that together account for approximately 8-9% of the genomic DNA. At least 40 different HERV groups have been assigned to three major HERV classes on the basis of their homologies to exogenous retroviruses. Although most HERVs are silenced by a variety of genetic and epigenetic mechanisms, they may be reactivated by environmental stimuli such as exogenous viruses and thus may contribute to pathogenic conditions. The objective of this study was to perform an in-depth analysis of the influence of HIV-1 infection on HERV activity in different cell types. RESULTS A retrovirus-specific microarray that covers major HERV groups from all three classes was used to analyze HERV transcription patterns in three persistently HIV-1 infected cell lines of different cellular origins and in their uninfected counterparts. All three persistently infected cell lines showed increased transcription of multiple class I and II HERV groups. Up-regulated transcription of five HERV taxa (HERV-E, HERV-T, HERV-K (HML-10) and two ERV9 subgroups) was confirmed by quantitative reverse transcriptase PCR analysis and could be reversed by knock-down of HIV-1 expression with HIV-1-specific siRNAs. Cells infected de novo by HIV-1 showed stronger transcriptional up-regulation of the HERV-K (HML-2) group than persistently infected cells of the same origin. Analysis of transcripts from individual members of this group revealed up-regulation of predominantly two proviral loci (ERVK-7 and ERVK-15) on chromosomes 1q22 and 7q34 in persistently infected KE37.1 cells, as well as in de novo HIV-1 infected LC5 cells, while only one single HML-2 locus (ERV-K6) on chromosome 7p22.1 was activated in persistently infected LC5 cells. CONCLUSIONS Our results demonstrate that HIV-1 can alter HERV transcription patterns of infected cells and indicate a correlation between activation of HERV elements and the level of HIV-1 production. Moreover, our results suggest that the effects of HIV-1 on HERV activity may be far more extensive and complex than anticipated from initial studies with clinical material.
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Affiliation(s)
- Michelle Vincendeau
- Institute of Virology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany. .,Research Unit Cellular Signal Integration, Institute of Molecular Toxicology and Pharmacology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany.
| | - Ingmar Göttesdorfer
- Institute of Virology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany.
| | - Julia M H Schreml
- Department of Hematology and Oncology, University Hospital Mannheim, University of Heidelberg, Mannheim, Germany.
| | - Armand G Ngounou Wetie
- Institute of Virology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany.
| | - Jens Mayer
- Department of Human Genetics, Center of Human and Molecular Biology, Medical Faculty, University of Saarland, Homburg, Germany.
| | - Alex D Greenwood
- Department of Wildlife Diseases, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany.
| | - Markus Helfer
- Institute of Virology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany.
| | - Susanne Kramer
- Institute of Virology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany.
| | - Wolfgang Seifarth
- Department of Hematology and Oncology, University Hospital Mannheim, University of Heidelberg, Mannheim, Germany.
| | - Kamyar Hadian
- Research Unit Cellular Signal Integration, Institute of Molecular Toxicology and Pharmacology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany. .,Assay Development and Screening Platform, Institute of Molecular Toxicology and Pharmacology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany.
| | - Ruth Brack-Werner
- Institute of Virology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany.
| | - Christine Leib-Mösch
- Institute of Virology, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany. .,Department of Hematology and Oncology, University Hospital Mannheim, University of Heidelberg, Mannheim, Germany.
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Agoni L, Lenz J, Guha C. Variant splicing and influence of ionizing radiation on human endogenous retrovirus K (HERV-K) transcripts in cancer cell lines. PLoS One 2013; 8:e76472. [PMID: 24204631 PMCID: PMC3799738 DOI: 10.1371/journal.pone.0076472] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 08/27/2013] [Indexed: 11/17/2022] Open
Abstract
Human endogenous retrovirus K (HERV-K) is the most intact retrovirus in the human genome. There are multiple full-length or near full-length HERV-K proviruses in it. To analyze which HERV-K proviruses give rise to viral transcripts in cancer cell lines and to test whether ionizing radiation can alter the levels of HERV-K transcripts, RT-PCR studies were undertaken using multiple human cancer cell lines. Primers from several positions in the viral genome were used and included pairs designed to cross splice junctions in viral RNAs. In the absence of ionizing radiation, transcripts were detected from multiple HERV-K proviruses in cell lines from human prostate, cervical, head and neck, or breast cancers, and the proviruses from which the transcripts originated varied among the different lines. Only one of 13 cell lines tested (cervical cancer line C33A) failed to show HERV-K transcripts. Spliced RNAs detected included viral RNAs spliced as expected at the conventional viral splice sites, plus several alternatively spliced RNAs. Alternatively spliced transcripts arose from specific proviruses, and were detected in most of the cell lines used. Quantitative RT-PCR was performed to assess the effects of ionizing radiation. These analyses showed that HERV-K transcripts were elevated in four of twelve lines tested, specifically all three prostate cancer lines used and one breast cancer line. The increases were transient, peaking at 24 hours following a single dose of gamma-irradiation that ranged from 2.5 to 20 Gy, and returning to baseline levels by 72 hours. In summary, these studies showed that ionizing radiation can affect the levels of HERV-K transcripts in cells, and these effects vary among different cells. The changes in HERV-K transcript levels might affect multiple biological processes in cells, and future studies of the effects of ionizing radiation on HERV-K are worth pursuing.
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Affiliation(s)
- Lorenzo Agoni
- Department of Pathology, Albert Einstein College of Medicine, Bronx, New York, United States of America
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Agoni L, Guha C, Lenz J. Detection of Human Endogenous Retrovirus K (HERV-K) Transcripts in Human Prostate Cancer Cell Lines. Front Oncol 2013; 3:180. [PMID: 23847768 PMCID: PMC3705622 DOI: 10.3389/fonc.2013.00180] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 06/26/2013] [Indexed: 12/22/2022] Open
Abstract
Human endogenous retroviruses (HERVs) are transcribed in many cancers including prostate cancer. Human endogenous retrovirus K (HERV-K) of the HML2 subtype is the most recently integrated and most intact retrovirus in the human genome, with many of the viral genomes encoding full- or partial-length viral proteins. To assess transcripts of HERV-K in prostate cancer cell lines and identify the specific HERV-K elements in the human genome that are transcribed, reverse transcriptase-PCR (RT-PCR) and cDNA sequencing were undertaken. Strand-specific RT-PCR, plasmid subcloning, and cDNA sequencing detected the presence of HERV-K(HML2) coding strand transcripts within four prostate cell lines (LNCaP, DU145, PC3, and VCaP). RT-PCR across splice junctions revealed splicing variants for env gene mRNA in three cell lines, two involving previously undescribed alternative splice sites. To determine the HERV-K loci from which the transcripts arose, RepeatMasker was used to compile a list of over 200 HERV-K internal genome segment fragments and over 1,000 HERV-K solo long terminal repeat (LTR) fragments in the human genome. Surprisingly, the sequences identified from internal positions of the viral genome were mostly smaller segments, while the LTRs were relatively intact. Possible reasons for this are discussed. The transcripts in the cell lines tested, arose from several HERV-K loci, with some proviruses being detected in multiple cell lines and others in only one of the four used. In some instances, transcripts from viral antisense strands was also detected. In addition, transcripts from both strands of solo LTRs were detected. These data show that transcripts from HERV-K loci commonly occur in prostate cancer cell lines and that transcription of either strand can occur. They also emphasize the importance of single nucleotide level analysis to identify the specific, individual HERV-K loci that are transcribed, and indicate that HERV-K expression in prostate cancer warrants further study.
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Affiliation(s)
- Lorenzo Agoni
- Department of Pathology, Albert Einstein College of Medicine , Bronx, NY , USA
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Human endogenous retrovirus K Gag coassembles with HIV-1 Gag and reduces the release efficiency and infectivity of HIV-1. J Virol 2012; 86:11194-208. [PMID: 22855497 DOI: 10.1128/jvi.00301-12] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Human endogenous retroviruses (HERVs), which are remnants of ancestral retroviruses integrated into the human genome, are defective in viral replication. Because activation of HERV-K and coexpression of this virus with HIV-1 have been observed during HIV-1 infection, it is conceivable that HERV-K could affect HIV-1 replication, either by competition or by cooperation, in cells expressing both viruses. In this study, we found that the release efficiency of HIV-1 Gag was 3-fold reduced upon overexpression of HERV-K(CON) Gag. In addition, we observed that in cells expressing Gag proteins of both viruses, HERV-K(CON) Gag colocalized with HIV-1 Gag at the plasma membrane. Furthermore, HERV-K(CON) Gag was found to coassemble with HIV-1 Gag, as demonstrated by (i) processing of HERV-K(CON) Gag by HIV-1 protease in virions, (ii) coimmunoprecipitation of virion-associated HERV-K(CON) Gag with HIV-1 Gag, and (iii) rescue of a late-domain-defective HERV-K(CON) Gag by wild-type (WT) HIV-1 Gag. Myristylation-deficient HERV-K(CON) Gag localized to nuclei, suggesting cryptic nuclear trafficking of HERV-K Gag. Notably, unlike WT HERV-K(CON) Gag, HIV-1 Gag failed to rescue myristylation-deficient HERV-K(CON) Gag to the plasma membrane. Efficient colocalization and coassembly of HIV-1 Gag and HERV-K Gag also required nucleocapsid (NC). These results provide evidence that HIV-1 Gag heteromultimerizes with HERV-K Gag at the plasma membrane, presumably through NC-RNA interaction. Intriguingly, HERV-K Gag overexpression reduced not only HIV-1 release efficiency but also HIV-1 infectivity in a myristylation- and NC-dependent manner. Altogether, these results indicate that Gag proteins of endogenous retroviruses can coassemble with HIV-1 Gag and modulate the late phase of HIV-1 replication.
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Jha AR, Nixon DF, Rosenberg MG, Martin JN, Deeks SG, Hudson RR, Garrison KE, Pillai SK. Human endogenous retrovirus K106 (HERV-K106) was infectious after the emergence of anatomically modern humans. PLoS One 2011; 6:e20234. [PMID: 21633511 PMCID: PMC3102101 DOI: 10.1371/journal.pone.0020234] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Accepted: 04/19/2011] [Indexed: 01/08/2023] Open
Abstract
HERV-K113 and HERV-K115 have been considered to be among the youngest HERVs because they are the only known full-length proviruses that are insertionally polymorphic and maintain the open reading frames of their coding genes. However, recent data suggest that HERV-K113 is at least 800,000 years old, and HERV-K115 even older. A systematic study of HERV-K HML2 members to identify HERVs that may have infected the human genome in the more recent evolutionary past is lacking. Therefore, we sought to determine how recently HERVs were exogenous and infectious by examining sequence variation in the long terminal repeat (LTR) regions of all full-length HERV-K loci. We used the traditional method of inter-LTR comparison to analyze all full length HERV-Ks and determined that two insertions, HERV-K106 and HERV-K116 have no differences between their 5′ and 3′ LTR sequences, suggesting that these insertions were endogenized in the recent evolutionary past. Among these insertions with no sequence differences between their LTR regions, HERV-K106 had the most intact viral sequence structure. Coalescent analysis of HERV-K106 3′ LTR sequences representing 51 ethnically diverse individuals suggests that HERV-K106 integrated into the human germ line approximately 150,000 years ago, after the emergence of anatomically modern humans.
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Affiliation(s)
- Aashish R. Jha
- Department of Human Genetics, University of Chicago, Chicago, Illinois, United States of America
- * E-mail: (ARJ); (SKP)
| | - Douglas F. Nixon
- Division of Experimental Medicine, University of California San Francisco, San Francisco, California, United States of America
| | | | - Jeffrey N. Martin
- HIV/AIDS Division, Department of Medicine, San Francisco General Hospital, University of California San Francisco, San Francisco, California, United States of America
| | - Steven G. Deeks
- HIV/AIDS Division, Department of Medicine, San Francisco General Hospital, University of California San Francisco, San Francisco, California, United States of America
| | - Richard R. Hudson
- Department of Evolution and Ecology, The University of Chicago, Chicago, Illinois, United States of America
| | - Keith E. Garrison
- Department of Biology, Saint Mary's College of California, Moraga, California, United States of America
| | - Satish K. Pillai
- Division of Infectious Diseases, Department of Medicine, San Francisco Veterans Affairs Medical Center, University of California San Francisco, San Francisco, California, United States of America
- * E-mail: (ARJ); (SKP)
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George M, Schwecke T, Beimforde N, Hohn O, Chudak C, Zimmermann A, Kurth R, Naumann D, Bannert N. Identification of the protease cleavage sites in a reconstituted Gag polyprotein of an HERV-K(HML-2) element. Retrovirology 2011; 8:30. [PMID: 21554716 PMCID: PMC3114732 DOI: 10.1186/1742-4690-8-30] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Accepted: 05/09/2011] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND The human genome harbors several largely preserved HERV-K(HML-2) elements. Although this retroviral family comes closest of all known HERVs to producing replication competent virions, mutations acquired during their chromosomal residence have rendered them incapable of expressing infectious particles. This also holds true for the HERV-K113 element that has conserved open reading frames (ORFs) for all its proteins in addition to a functional LTR promoter. Uncertainty concerning the localization and impact of post-insertional mutations has greatly hampered the functional characterization of these ancient retroviruses and their proteins. However, analogous to other betaretroviruses, it is known that HERV-K(HML-2) virions undergo a maturation process during or shortly after release from the host cell. During this process, the subdomains of the Gag polyproteins are released by proteolytic cleavage, although the nature of the mature HERV-K(HML-2) Gag proteins and the exact position of the cleavage sites have until now remained unknown. RESULTS By aligning the amino acid sequences encoded by the gag-pro-pol ORFs of HERV-K113 with the corresponding segments from 10 other well-preserved human specific elements we identified non-synonymous post-insertional mutations that have occurred in this region of the provirus. Reversion of these mutations and a partial codon optimization facilitated the large-scale production of maturation-competent HERV-K113 virus-like particles (VLPs). The Gag subdomains of purified mature VLPs were separated by reversed-phase high-pressure liquid chromatography and initially characterized using specific antibodies. Cleavage sites were identified by mass spectrometry and N-terminal sequencing and confirmed by mutagenesis. Our results indicate that the gag gene product Pr74Gag of HERV-K(HML-2) is processed to yield p15-MA (matrix), SP1 (spacer peptide of 14 amino acids), p15, p27-CA (capsid), p10-NC (nucleocapsid) and two C-terminally encoded glutamine- and proline-rich peptides, QP1 and QP2, spanning 23 and 19 amino acids, respectively. CONCLUSIONS Expression of reconstituted sequences of original HERV elements is an important tool for studying fundamental aspects of the biology of these ancient viruses. The analysis of HERV-K(HML-2) Gag processing and the nature of the mature Gag proteins presented here will facilitate further studies of the discrete functions of these proteins and of their potential impact on the human host.
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Affiliation(s)
- Maja George
- Center for HIV and Retrovirology, Robert Koch Institute, Nordufer 20, 13353 Berlin, Germany
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Ryan FP. An alternative approach to medical genetics based on modern evolutionary biology. Part 2: retroviral symbiosis. J R Soc Med 2009; 102:324-31. [PMID: 19679734 DOI: 10.1258/jrsm.2009.090183] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Frank P Ryan
- Sheffield Primary Care Trust and Department of Animal and Plant Sciences, Sheffield University, Sheffield, UK.
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Reconstitution of the ancestral glycoprotein of human endogenous retrovirus k and modulation of its functional activity by truncation of the cytoplasmic domain. J Virol 2009; 83:12790-800. [PMID: 19812154 DOI: 10.1128/jvi.01368-09] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Endogenous retroviruses present in the human genome provide a rich record of ancient infections. All presently recognized elements, including the youngest and most intact proviruses of the human endogenous retrovirus K(HML-2) [HERV-K(HML-2)] family, have suffered postinsertional mutations during their time of chromosomal residence, and genes encoding the envelope glycoprotein (Env) have not been spared these mutations. In this study, we have, for the first time, reconstituted an authentic Env of a HERV-K(HML-2) provirus by back mutation of putative postinsertional amino acid changes of the protein encoded by HERV-K113. Aided by codon-optimized expression, we demonstrate that the reconstituted Env regained its ability to be incorporated into retroviral particles and to mediate entry. The original ancient HERV-K113 Env was synthesized as a moderately glycosylated gp95 precursor protein cleaved into surface and transmembrane (TM) subunits. Of the nine N-linked oligosaccharides, four are part of the TM subunit, contributing 15 kDa to its apparent molecular mass of 41 kDa. The carbohydrates, as well as the cytoplasmic tail, are critical for efficient intracellular trafficking, processing, stability, and particle incorporation. Whereas deletions of the carboxy-terminal 6 residues completely abrogated cleavage and virion association, more extensive truncations slightly enhanced incorporation but dramatically increased the ability to mediate entry of pseudotyped lentiviruses. Although the first HERV-K(HML-2) elements infected human ancestors about 30 million years ago, our findings indicate that their glycoproteins are in most respects remarkably similar to those of classical contemporary retroviruses and can still mediate efficient entry into mammalian cells.
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