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Harris JM, Magri A, Faria AR, Tsukuda S, Balfe P, Wing PAC, McKeating JA. Oxygen-dependent histone lysine demethylase 4 restricts hepatitis B virus replication. J Biol Chem 2024; 300:105724. [PMID: 38325742 PMCID: PMC10914488 DOI: 10.1016/j.jbc.2024.105724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 01/25/2024] [Accepted: 02/01/2024] [Indexed: 02/09/2024] Open
Abstract
Mammalian cells have evolved strategies to regulate gene expression when oxygen is limited. Hypoxia-inducible factors (HIF) are the major transcriptional regulators of host gene expression. We previously reported that HIFs bind and activate hepatitis B virus (HBV) DNA transcription under low oxygen conditions; however, the global cellular response to low oxygen is mediated by a family of oxygenases that work in concert with HIFs. Recent studies have identified a role for chromatin modifiers in sensing cellular oxygen and orchestrating transcriptional responses, but their role in the HBV life cycle is as yet undefined. We demonstrated that histone lysine demethylase 4 (KDM4) can restrict HBV, and pharmacological or oxygen-mediated inhibition of the demethylase increases viral RNAs derived from both episomal and integrated copies of the viral genome. Sequencing studies demonstrated that KDM4 is a major regulator of the hepatic transcriptome, which defines hepatocellular permissivity to HBV infection. We propose a model where HBV exploits cellular oxygen sensors to replicate and persist in the liver. Understanding oxygen-dependent pathways that regulate HBV infection will facilitate the development of physiologically relevant cell-based models that support efficient HBV replication.
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Affiliation(s)
- James M Harris
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Andrea Magri
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Ana Rita Faria
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Senko Tsukuda
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Peter Balfe
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Peter A C Wing
- Nuffield Department of Medicine, University of Oxford, Oxford, UK; Chinese Academy of Medical Sciences Oxford Institute, University of Oxford, Oxford, UK.
| | - Jane A McKeating
- Nuffield Department of Medicine, University of Oxford, Oxford, UK; Chinese Academy of Medical Sciences Oxford Institute, University of Oxford, Oxford, UK.
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2
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Porter VL, O'Neill K, MacLennan S, Corbett RD, Ng M, Culibrk L, Hamadeh Z, Iden M, Schmidt R, Tsaih SW, Chang G, Fan J, Nip KM, Akbari V, Chan SK, Hopkins J, Moore RA, Chuah E, Mungall KL, Mungall AJ, Birol I, Jones SJM, Rader JS, Marra MA. Genomic structures and regulation patterns at HPV integration sites in cervical cancer. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.04.564800. [PMID: 37961641 PMCID: PMC10635144 DOI: 10.1101/2023.11.04.564800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Human papillomavirus (HPV) integration has been implicated in transforming HPV infection into cancer, but its genomic consequences have been difficult to study using short-read technologies. To resolve the dysregulation associated with HPV integration, we performed long-read sequencing on 63 cervical cancer genomes. We identified six categories of integration events based on HPV-human genomic structures. Of all HPV integrants, defined as two HPV-human breakpoints bridged by an HPV sequence, 24% contained variable copies of HPV between the breakpoints, a phenomenon we termed heterologous integration. Analysis of DNA methylation within and in proximity to the HPV genome at individual integration events revealed relationships between methylation status of the integrant and its orientation and structure. Dysregulation of the human epigenome and neighboring gene expression in cis with the HPV-integrated allele was observed over megabase-ranges of the genome. By elucidating the structural, epigenetic, and allele-specific impacts of HPV integration, we provide insight into the role of integrated HPV in cervical cancer.
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3
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MacLennan SA, Marra MA. Oncogenic Viruses and the Epigenome: How Viruses Hijack Epigenetic Mechanisms to Drive Cancer. Int J Mol Sci 2023; 24:ijms24119543. [PMID: 37298494 DOI: 10.3390/ijms24119543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 05/26/2023] [Accepted: 05/29/2023] [Indexed: 06/12/2023] Open
Abstract
Globally, viral infections substantially contribute to cancer development. Oncogenic viruses are taxonomically heterogeneous and drive cancers using diverse strategies, including epigenomic dysregulation. Here, we discuss how oncogenic viruses disrupt epigenetic homeostasis to drive cancer and focus on how virally mediated dysregulation of host and viral epigenomes impacts the hallmarks of cancer. To illustrate the relationship between epigenetics and viral life cycles, we describe how epigenetic changes facilitate the human papillomavirus (HPV) life cycle and how changes to this process can spur malignancy. We also highlight the clinical impact of virally mediated epigenetic changes on cancer diagnosis, prognosis, and treatment.
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Affiliation(s)
- Signe A MacLennan
- Department of Medical Genetics, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, BC V5Z 4S6, Canada
| | - Marco A Marra
- Department of Medical Genetics, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, BC V5Z 4S6, Canada
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4
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Varghese CS, Parish JL, Ferguson J. Lying low-chromatin insulation in persistent DNA virus infection. Curr Opin Virol 2022; 55:101257. [PMID: 35998396 DOI: 10.1016/j.coviro.2022.101257] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 07/08/2022] [Accepted: 07/28/2022] [Indexed: 11/03/2022]
Abstract
Persistent virus infections are achieved when the intricate balance of virus replication, host-cell division and successful immune evasion is met. The genomes of persistent DNA viruses are either maintained as extrachromosomal episomes or can integrate into the host genome. Common to both these strategies of persistence is the chromatinisation of viral DNA by cellular histones which, like host DNA, are subject to epigenetic modification. Epigenetic repression of viral genes required for lytic replication occurs, while genes required for latent or persistent infection are maintained in an active chromatin state. Viruses utilise host-cell chromatin insulators, which function to maintain epigenetic boundaries and enforce this strict transcriptional programme. Here, we review insulator protein function in virus transcription control, focussing on CCCTC-binding factor (CTCF) and cofactors. We describe CTCF-dependent activities in virus transcription regulation through epigenetic and promoter-enhancer insulation, three-dimensional chromatin looping and manipulation of transcript splicing.
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Affiliation(s)
- Christy S Varghese
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, B15 2TT, UK
| | - Joanna L Parish
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, B15 2TT, UK.
| | - Jack Ferguson
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, B15 2TT, UK
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5
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Castro-Oropeza R, Piña-Sánchez P. Epigenetic and Transcriptomic Regulation Landscape in HPV+ Cancers: Biological and Clinical Implications. Front Genet 2022; 13:886613. [PMID: 35774512 PMCID: PMC9237502 DOI: 10.3389/fgene.2022.886613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 05/24/2022] [Indexed: 11/13/2022] Open
Abstract
Human Papillomavirus (HPV) is an oncogenic virus that causes the highest number of viral-associated cancer cases and deaths worldwide, with more than 690,000 new cases per year and 342,000 deaths only for cervical cancer (CC). Although the incidence and mortality rates for CC are declining in countries where screening and vaccination programs have been implemented, other types of cancer in which HPV is involved, such as oropharyngeal cancer, are increasing, particularly in men. Mutational and transcriptional profiles of various HPV-associated neoplasms have been described, and accumulated evidence has shown the oncogenic capacity of E6, E7, and E5 genes of high-risk HPV. Interestingly, transcriptomic analysis has revealed that although a vast majority of the human genome is transcribed into RNAs, only 2% of transcripts are translated into proteins. The remaining transcripts lacking protein-coding potential are called non-coding RNAs. In addition to the transfer and ribosomal RNAs, there are regulatory non-coding RNAs classified according to size and structure in long non-coding RNAs (lncRNAs), circular RNAs (circRNAs), and small RNAs; such as microRNAs (miRNAs), piwi-associated RNAs (piRNAs), small nucleolar RNAs (snoRNAs) and endogenous short-interfering RNAs. Recent evidence has shown that lncRNAs, miRNAs, and circRNAs are aberrantly expressed under pathological conditions such as cancer. In addition, those transcripts are dysregulated in HPV-related neoplasms, and their expression correlates with tumor progression, metastasis, poor prognosis, and recurrence. Nuclear lncRNAs are epigenetic regulators involved in controlling gene expression at the transcriptional level through chromatin modification and remodeling. Moreover, disruption of the expression profiles of those lncRNAs affects multiple biological processes such as cell proliferation, apoptosis, and migration. This review highlights the epigenetic alterations induced by HPV, from infection to neoplastic transformation. We condense the epigenetic role of non-coding RNA alterations and their potential as biomarkers in transformation’s early stages and clinical applications. We also summarize the molecular mechanisms of action of nuclear lncRNAs to understand better their role in the epigenetic control of gene expression and how they can drive the malignant phenotype of HPV-related neoplasia. Finally, we review several chemical and epigenetic therapy options to prevent and treat HPV-associated neoplasms.
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6
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Groves IJ, Drane ELA, Michalski M, Monahan JM, Scarpini CG, Smith SP, Bussotti G, Várnai C, Schoenfelder S, Fraser P, Enright AJ, Coleman N. Short- and long-range cis interactions between integrated HPV genomes and cellular chromatin dysregulate host gene expression in early cervical carcinogenesis. PLoS Pathog 2021; 17:e1009875. [PMID: 34432858 PMCID: PMC8439666 DOI: 10.1371/journal.ppat.1009875] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 09/14/2021] [Accepted: 08/07/2021] [Indexed: 12/26/2022] Open
Abstract
Development of cervical cancer is directly associated with integration of human papillomavirus (HPV) genomes into host chromosomes and subsequent modulation of HPV oncogene expression, which correlates with multi-layered epigenetic changes at the integrated HPV genomes. However, the process of integration itself and dysregulation of host gene expression at sites of integration in our model of HPV16 integrant clone natural selection has remained enigmatic. We now show, using a state-of-the-art 'HPV integrated site capture' (HISC) technique, that integration likely occurs through microhomology-mediated repair (MHMR) mechanisms via either a direct process, resulting in host sequence deletion (in our case, partially homozygously) or via a 'looping' mechanism by which flanking host regions become amplified. Furthermore, using our 'HPV16-specific Region Capture Hi-C' technique, we have determined that chromatin interactions between the integrated virus genome and host chromosomes, both at short- (<500 kbp) and long-range (>500 kbp), appear to drive local host gene dysregulation through the disruption of host:host interactions within (but not exceeding) host structures known as topologically associating domains (TADs). This mechanism of HPV-induced host gene expression modulation indicates that integration of virus genomes near to or within a 'cancer-causing gene' is not essential to influence their expression and that these modifications to genome interactions could have a major role in selection of HPV integrants at the early stage of cervical neoplastic progression.
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Affiliation(s)
- Ian J. Groves
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Emma L. A. Drane
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Marco Michalski
- Nuclear Dynamics Programme, Babraham Institute, Cambridge, United Kingdom
| | - Jack M. Monahan
- EMBL-European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, United Kingdom
| | - Cinzia G. Scarpini
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Stephen P. Smith
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Giovanni Bussotti
- EMBL-European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, United Kingdom
| | - Csilla Várnai
- Nuclear Dynamics Programme, Babraham Institute, Cambridge, United Kingdom
| | | | - Peter Fraser
- Nuclear Dynamics Programme, Babraham Institute, Cambridge, United Kingdom
- Department of Biological Science, Florida State University, Tallahassee, Florida, United States of America
| | - Anton J. Enright
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
- EMBL-European Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, United Kingdom
| | - Nicholas Coleman
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
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7
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Gagliardi A, Porter VL, Zong Z, Bowlby R, Titmuss E, Namirembe C, Griner NB, Petrello H, Bowen J, Chan SK, Culibrk L, Darragh TM, Stoler MH, Wright TC, Gesuwan P, Dyer MA, Ma Y, Mungall KL, Jones SJM, Nakisige C, Novik K, Orem J, Origa M, Gastier-Foster JM, Yarchoan R, Casper C, Mills GB, Rader JS, Ojesina AI, Gerhard DS, Mungall AJ, Marra MA. Analysis of Ugandan cervical carcinomas identifies human papillomavirus clade-specific epigenome and transcriptome landscapes. Nat Genet 2020; 52:800-810. [PMID: 32747824 PMCID: PMC7498180 DOI: 10.1038/s41588-020-0673-7] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 06/26/2020] [Indexed: 01/18/2023]
Abstract
Cervical cancer is the most common cancer affecting sub-Saharan African women and is prevalent among HIV-positive (HIV+) individuals. No comprehensive profiling of cancer genomes, transcriptomes or epigenomes has been performed in this population thus far. We characterized 118 tumors from Ugandan patients, of whom 72 were HIV+, and performed extended mutation analysis on an additional 89 tumors. We detected human papillomavirus (HPV)-clade-specific differences in tumor DNA methylation, promoter- and enhancer-associated histone marks, gene expression and pathway dysregulation. Changes in histone modification at HPV integration events were correlated with upregulation of nearby genes and endogenous retroviruses.
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Affiliation(s)
- Alessia Gagliardi
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, British Columbia, Canada
| | - Vanessa L Porter
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, British Columbia, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Zusheng Zong
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, British Columbia, Canada
| | - Reanne Bowlby
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, British Columbia, Canada
| | - Emma Titmuss
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, British Columbia, Canada
| | | | - Nicholas B Griner
- Office of Cancer Genomics, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | | | - Jay Bowen
- Nationwide Children's Hospital, Columbus, OH, USA
| | - Simon K Chan
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, British Columbia, Canada
| | - Luka Culibrk
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, British Columbia, Canada
| | - Teresa M Darragh
- Department of Pathology, University of California at San Francisco, San Francisco, CA, USA
| | - Mark H Stoler
- Department of Pathology, University of Virginia, Charlottesville, VA, USA
| | - Thomas C Wright
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Patee Gesuwan
- Office of Cancer Genomics, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Maureen A Dyer
- Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Yussanne Ma
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, British Columbia, Canada
| | - Karen L Mungall
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, British Columbia, Canada
| | - Steven J M Jones
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, British Columbia, Canada
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Karen Novik
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, British Columbia, Canada
| | | | | | - Julie M Gastier-Foster
- Nationwide Children's Hospital, Columbus, OH, USA
- Departments of Pathology and Pediatrics, The Ohio State University, Columbus, OH, USA
| | - Robert Yarchoan
- Office of HIV and AIDS Malignancy, National Cancer Institute, National Institues of Health, Bethesda, MD, USA
- HIV and AIDS Malignancy Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Corey Casper
- Infectious Disease Research Institute, Seattle, WA, USA
| | - Gordon B Mills
- Knight Cancer Institute, Oregon Health and Science University, Portland, OR, USA
| | - Janet S Rader
- Department of Obstetrics and Gynecology, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Akinyemi I Ojesina
- Department of Epidemiology, University of Alabama at Birmingham, Birmingham, AL, USA
- O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL, USA
- HudsonAlpha Institute for Biotechnology, Huntsville, AL, USA
| | - Daniela S Gerhard
- Office of Cancer Genomics, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Andrew J Mungall
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, British Columbia, Canada
| | - Marco A Marra
- Canada's Michael Smith Genome Sciences Centre, BC Cancer, Vancouver, British Columbia, Canada.
- Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada.
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8
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Epigenetic Regulation of the Human Papillomavirus Life Cycle. Pathogens 2020; 9:pathogens9060483. [PMID: 32570816 PMCID: PMC7350343 DOI: 10.3390/pathogens9060483] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 06/16/2020] [Accepted: 06/17/2020] [Indexed: 12/20/2022] Open
Abstract
Persistent infection with certain types of human papillomaviruses (HPVs), termed high risk, presents a public health burden due to their association with multiple human cancers, including cervical cancer and an increasing number of head and neck cancers. Despite the development of prophylactic vaccines, the incidence of HPV-associated cancers remains high. In addition, no vaccine has yet been licensed for therapeutic use against pre-existing HPV infections and HPV-associated diseases. Although persistent HPV infection is the major risk factor for cancer development, additional genetic and epigenetic alterations are required for progression to the malignant phenotype. Unlike genetic mutations, the reversibility of epigenetic modifications makes epigenetic regulators ideal therapeutic targets for cancer therapy. This review article will highlight the recent advances in the understanding of epigenetic modifications associated with HPV infections, with a particular focus on the role of these epigenetic changes during different stages of the HPV life cycle that are closely associated with activation of DNA damage response pathways.
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9
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Lai Y, He Z, Zhang A, Yan Z, Zhang X, Hu S, Wang N, He H. Tip60 and p300 function antagonistically in the epigenetic regulation of HPV18 E6/E7 genes in cervical cancer HeLa cells. Genes Genomics 2020; 42:691-698. [PMID: 32399935 DOI: 10.1007/s13258-020-00938-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Accepted: 04/27/2020] [Indexed: 11/26/2022]
Abstract
BACKGROUND High-risk HPV is a causative factor of cervical cancer. HPV DNA fragments integrate into host genome resulting in the constitutive expression of HPV genes E6 and E7 under the regulation of transcription factors, such as p300 and Tip60. Interestingly, Tip60, a factor with HAT (histone acetyl transferase) activity, represses HPV18 E6/E7 genes while another HAT p300 activates the transcription of HPV18 E6/E7. OBJECTIVE To explore the mechanism for the opposite roles of Tip60 and p300 in the virus gene regulation, and the influence of Tip60 and p300 in histone modifications in the regulatory sequence of HPV18 genes. METHODS Tip60 or p300 was either knocked down or overexpressed in HeLa cells. The effects on HPV E6E7 expression were determined with RT-qPCR. The association of RNA polymerase II and the enrichment of acetylated or methylated histones in HPV promoter region were measured by ChIP assays with specific antibodies. RESULTS ChIP results showed that Tip60 and p300 differently affected the modifications of histone H3K9 and the deposition of nucleosomes in HPV18 long control region (LCR). HPV18 LCR in HeLa cells is bivalent chromatin carrying both the active histone H3K9 acetylation mark and the repressive histone H3K9 trimethylation mark, the balance is maintained by Tip60 and p300. CONCLUSION(S) Based on the roles of Tip60 and p300 in HPV gene regulation, chemical compounds targeting Tip60 or p300 are potential anti-cervical cancer drugs.
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Affiliation(s)
- Yongwei Lai
- Key Laboratory of Industrial Microbiology, Ministry of Education and Tianjin City State Key Laboratory of Food Nutrition and Safety College of Biotechnology, Tianjin University of Science and Technology, No. 29, 13th. Avenue, Tianjin Economic and Technological Development Area (TEDA), Tianjin, 300457, People's Republic of China
- Department of Pharmacology, Jilin Medical University, Jilin City, 132013, Jilin Province, People's Republic of China
| | - Zhao He
- Key Laboratory of Industrial Microbiology, Ministry of Education and Tianjin City State Key Laboratory of Food Nutrition and Safety College of Biotechnology, Tianjin University of Science and Technology, No. 29, 13th. Avenue, Tianjin Economic and Technological Development Area (TEDA), Tianjin, 300457, People's Republic of China
| | - Aowei Zhang
- Key Laboratory of Industrial Microbiology, Ministry of Education and Tianjin City State Key Laboratory of Food Nutrition and Safety College of Biotechnology, Tianjin University of Science and Technology, No. 29, 13th. Avenue, Tianjin Economic and Technological Development Area (TEDA), Tianjin, 300457, People's Republic of China
| | - Zhinan Yan
- Key Laboratory of Industrial Microbiology, Ministry of Education and Tianjin City State Key Laboratory of Food Nutrition and Safety College of Biotechnology, Tianjin University of Science and Technology, No. 29, 13th. Avenue, Tianjin Economic and Technological Development Area (TEDA), Tianjin, 300457, People's Republic of China
| | - Xiao Zhang
- Key Laboratory of Industrial Microbiology, Ministry of Education and Tianjin City State Key Laboratory of Food Nutrition and Safety College of Biotechnology, Tianjin University of Science and Technology, No. 29, 13th. Avenue, Tianjin Economic and Technological Development Area (TEDA), Tianjin, 300457, People's Republic of China
| | - Shiyue Hu
- Key Laboratory of Industrial Microbiology, Ministry of Education and Tianjin City State Key Laboratory of Food Nutrition and Safety College of Biotechnology, Tianjin University of Science and Technology, No. 29, 13th. Avenue, Tianjin Economic and Technological Development Area (TEDA), Tianjin, 300457, People's Republic of China
| | - Nan Wang
- Key Laboratory of Industrial Microbiology, Ministry of Education and Tianjin City State Key Laboratory of Food Nutrition and Safety College of Biotechnology, Tianjin University of Science and Technology, No. 29, 13th. Avenue, Tianjin Economic and Technological Development Area (TEDA), Tianjin, 300457, People's Republic of China
| | - Hongpeng He
- Key Laboratory of Industrial Microbiology, Ministry of Education and Tianjin City State Key Laboratory of Food Nutrition and Safety College of Biotechnology, Tianjin University of Science and Technology, No. 29, 13th. Avenue, Tianjin Economic and Technological Development Area (TEDA), Tianjin, 300457, People's Republic of China.
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10
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Burley M, Roberts S, Parish JL. Epigenetic regulation of human papillomavirus transcription in the productive virus life cycle. Semin Immunopathol 2020; 42:159-171. [PMID: 31919577 PMCID: PMC7174255 DOI: 10.1007/s00281-019-00773-0] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 11/08/2019] [Indexed: 12/13/2022]
Abstract
Human papillomaviruses (HPV) are a large family of viruses which contain a circular, double-stranded DNA genome of approximately 8000 base pairs. The viral DNA is chromatinized by the recruitment of cellular histones which are subject to host cell-mediated post-translational epigenetic modification recognized as an important mechanism of virus transcription regulation. The HPV life cycle is dependent on the terminal differentiation of the target cell within epithelia-the keratinocyte. The virus life cycle begins in the undifferentiated basal compartment of epithelia where the viral chromatin is maintained in an epigenetically repressed state, stabilized by distal chromatin interactions between the viral enhancer and early gene region. Migration of the infected keratinocyte towards the surface of the epithelium induces cellular differentiation which disrupts chromatin looping and stimulates epigenetic remodelling of the viral chromatin. These epigenetic changes result in enhanced virus transcription and activation of the virus late promoter facilitating transcription of the viral capsid proteins. In this review article, we discuss the complexity of virus- and host-cell-mediated epigenetic regulation of virus transcription with a specific focus on differentiation-dependent remodelling of viral chromatin during the HPV life cycle.
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Affiliation(s)
- Megan Burley
- College of Medical and Dental Sciences, Institute of Cancer and Genomic Sciences, University of Birmingham, B152TT, Birmingham, UK
| | - Sally Roberts
- College of Medical and Dental Sciences, Institute of Cancer and Genomic Sciences, University of Birmingham, B152TT, Birmingham, UK
| | - Joanna L Parish
- College of Medical and Dental Sciences, Institute of Cancer and Genomic Sciences, University of Birmingham, B152TT, Birmingham, UK.
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11
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Xiao Z, He Y, Liu C, Xiang L, Yi J, Wang M, Shen T, Shen L, Xue Y, Shi H, Liu P. Targeting P16INK4A in uterine serous carcinoma through inhibition of histone demethylation. Oncol Rep 2019; 41:2667-2678. [PMID: 30896884 PMCID: PMC6448098 DOI: 10.3892/or.2019.7067] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 02/14/2019] [Indexed: 11/05/2022] Open
Abstract
Uterine serous carcinoma (USC) is a subtype of endometrial cancer. Compared with endometrial endometroid carcinoma, the majority of USC cases are more aggressive. Cyclin-dependent kinase inhibitor 2A (P16INK4A) is a canonical tumor suppressor that blocks cell cycle progression; however, P16INK4A is overexpressed in USC. The aim of the present study was to determine the role of P16INK4A in P16INK4A‑positive endometrial cancer, with the hope of elucidating a novel therapeutic approach for this type of malignancy. A total of 2 endometrial cancer cell lines, ETN‑1 and EFE‑184, were selected for further investigation, due to them being known to express high levels of P16INK4A. Using short hairpin RNA targeting P16INK4A, P16INK4A was downregulated in these cancer cell lines. Cell viability and migration were examined via 2D/3D clonogenic and wound healing assays. Subsequently, GSK‑J4, a histone demethylase inhibitor, was employed to deplete P16INK4A in these cancer cell lines and an ex vivo culture system of a patient‑derived xenograft (PDX) endometrial tumor sample. Following P16INK4A knockdown, the proliferation and migration of ETN‑1 and EFE‑184 cells markedly declined. When exposed to GSK‑J4, the levels of KDM6B and P16INK4A were almost completely abrogated, and the cell viability was significantly reduced in these cell lines and the ex vivo‑cultured PDX tumor explants. The association between the levels of P16INK4A, lysine demethylase 6B (KDM6B) and the methylation status of histone 3 lysine 27 (H3K27) in these cell lines and the human USC tumor sample was also demonstrated. P16INK4A appears to be oncogenic in a number of endometrial cancer cell lines. The level of P16INK4A is associated with the methylation status of H3K27. Increased methylation of H3K27 coexists with downregulation of KDM6B and, subsequently, P16INK4A, which reduces cell proliferation and invasiveness in endometrial cancer. The observations of the present study may enable the development of a novel therapeutic strategy for P16INK4A‑positive endometrial cancer, particularly USC.
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Affiliation(s)
- Zhen Xiao
- Department of Obstetrics and Gynecology, First Affiliated Hospital of Dalian Medical University, Dalian Medical University, Dalian, Liaoning 116011, P.R. China
| | - Yingying He
- Department of Obstetrics and Gynecology, First Affiliated Hospital of Dalian Medical University, Dalian Medical University, Dalian, Liaoning 116011, P.R. China
| | - Chongya Liu
- Institute of Cancer Stem Cell, Dalian Medical University, Dalian, Liaoning 116044, P.R. China
| | - Lin Xiang
- Institute of Cancer Stem Cell, Dalian Medical University, Dalian, Liaoning 116044, P.R. China
| | - Jingyan Yi
- Institute of Cancer Stem Cell, Dalian Medical University, Dalian, Liaoning 116044, P.R. China
| | - Min Wang
- Institute of Cancer Stem Cell, Dalian Medical University, Dalian, Liaoning 116044, P.R. China
| | - Tingting Shen
- Institute of Cancer Stem Cell, Dalian Medical University, Dalian, Liaoning 116044, P.R. China
| | - Lanlin Shen
- Institute of Cancer Stem Cell, Dalian Medical University, Dalian, Liaoning 116044, P.R. China
| | - Yijue Xue
- Institute of Cancer Stem Cell, Dalian Medical University, Dalian, Liaoning 116044, P.R. China
| | - Hong Shi
- Department of Obstetrics and Gynecology, First Affiliated Hospital of Dalian Medical University, Dalian Medical University, Dalian, Liaoning 116011, P.R. China
| | - Pixu Liu
- Institute of Cancer Stem Cell, Dalian Medical University, Dalian, Liaoning 116044, P.R. China
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12
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Pentland I, Campos-León K, Cotic M, Davies KJ, Wood CD, Groves IJ, Burley M, Coleman N, Stockton JD, Noyvert B, Beggs AD, West MJ, Roberts S, Parish JL. Disruption of CTCF-YY1-dependent looping of the human papillomavirus genome activates differentiation-induced viral oncogene transcription. PLoS Biol 2018; 16:e2005752. [PMID: 30359362 PMCID: PMC6219814 DOI: 10.1371/journal.pbio.2005752] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 11/06/2018] [Accepted: 10/12/2018] [Indexed: 11/19/2022] Open
Abstract
The complex life cycle of oncogenic human papillomavirus (HPV) initiates in undifferentiated basal epithelial keratinocytes where expression of the E6 and E7 oncogenes is restricted. Upon epithelial differentiation, E6/E7 transcription is increased through unknown mechanisms to drive cellular proliferation required to support virus replication. We report that the chromatin-organising CCCTC-binding factor (CTCF) promotes the formation of a chromatin loop in the HPV genome that epigenetically represses viral enhancer activity controlling E6/E7 expression. CTCF-dependent looping is dependent on the expression of the CTCF-associated Yin Yang 1 (YY1) transcription factor and polycomb repressor complex (PRC) recruitment, resulting in trimethylation of histone H3 at lysine 27. We show that viral oncogene up-regulation during cellular differentiation results from YY1 down-regulation, disruption of viral genome looping, and a loss of epigenetic repression of viral enhancer activity. Our data therefore reveal a key role for CTCF-YY1-dependent looping in the HPV life cycle and identify a regulatory mechanism that could be disrupted in HPV carcinogenesis.
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Affiliation(s)
- Ieisha Pentland
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Karen Campos-León
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Marius Cotic
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Kelli-Jo Davies
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom
| | - C. David Wood
- School of Life Sciences, University of Sussex, Falmer, Brighton, United Kingdom
| | - Ian J. Groves
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Megan Burley
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Nicholas Coleman
- Department of Pathology, University of Cambridge, Cambridge, United Kingdom
| | - Joanne D. Stockton
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Boris Noyvert
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Andrew D. Beggs
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Michelle J. West
- School of Life Sciences, University of Sussex, Falmer, Brighton, United Kingdom
| | - Sally Roberts
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom
| | - Joanna L. Parish
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, United Kingdom
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13
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Ajiro M, Sakai H, Onogi H, Yamamoto M, Sumi E, Sawada T, Nomura T, Kabashima K, Hosoya T, Hagiwara M. CDK9 Inhibitor FIT-039 Suppresses Viral Oncogenes E6 and E7 and Has a Therapeutic Effect on HPV-Induced Neoplasia. Clin Cancer Res 2018; 24:4518-4528. [DOI: 10.1158/1078-0432.ccr-17-3119] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2017] [Revised: 03/14/2018] [Accepted: 04/25/2018] [Indexed: 11/16/2022]
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14
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Abstract
Human papillomaviruses (HPVs) are an ancient group of viruses with small, double-stranded DNA circular genomes. They are species-specific and have a strict tropism for mucosal and cutaneous stratified squamous epithelial surfaces of the host. A subset of these viruses has been demonstrated to be the causative agent of several human cancers. Here, we review the biology, natural history, evolution and cancer association of the oncogenic HPVs.This article is part of the themed issue 'Human oncogenic viruses'.
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Affiliation(s)
- Alison A McBride
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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15
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Groves IJ, Coleman N. Human papillomavirus genome integration in squamous carcinogenesis: what have next-generation sequencing studies taught us? J Pathol 2018; 245:9-18. [PMID: 29443391 DOI: 10.1002/path.5058] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 02/01/2018] [Accepted: 02/06/2018] [Indexed: 12/31/2022]
Abstract
Human papillomavirus (HPV) infection is associated with ∼5% of all human cancers, including a range of squamous cell carcinomas. Persistent infection by high-risk HPVs (HRHPVs) is associated with the integration of virus genomes (which are usually stably maintained as extrachromosomal episomes) into host chromosomes. Although HRHPV integration rates differ across human sites of infection, this process appears to be an important event in HPV-associated neoplastic progression, leading to deregulation of virus oncogene expression, host gene expression modulation, and further genomic instability. However, the mechanisms by which HRHPV integration occur and by which the subsequent gene expression changes take place are incompletely understood. The advent of next-generation sequencing (NGS) of both RNA and DNA has allowed powerful interrogation of the association of HRHPVs with human disease, including precise determination of the sites of integration and the genomic rearrangements at integration loci. In turn, these data have indicated that integration occurs through two main mechanisms: looping integration and direct insertion. Improved understanding of integration sites is allowing further investigation of the factors that provide a competitive advantage to some integrants during disease progression. Furthermore, advanced approaches to the generation of genome-wide samples have given novel insights into the three-dimensional interactions within the nucleus, which could act as another layer of epigenetic control of both virus and host transcription. It is hoped that further advances in NGS techniques and analysis will not only allow the examination of further unanswered questions regarding HPV infection, but also direct new approaches to treating HPV-associated human disease. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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Affiliation(s)
- Ian J Groves
- Department of Pathology, University of Cambridge, Cambridge, UK
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16
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Cruz-Gregorio A, Manzo-Merino J, Lizano M. Cellular redox, cancer and human papillomavirus. Virus Res 2018; 246:35-45. [DOI: 10.1016/j.virusres.2018.01.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 01/10/2018] [Accepted: 01/10/2018] [Indexed: 12/28/2022]
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17
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Kucia-Tran JA, Tulkki V, Scarpini CG, Smith S, Wallberg M, Paez-Ribes M, Araujo AM, Botthoff J, Feeney M, Hughes K, Caffarel MM, Coleman N. Anti-oncostatin M antibody inhibits the pro-malignant effects of oncostatin M receptor overexpression in squamous cell carcinoma. J Pathol 2018; 244:283-295. [PMID: 29205362 DOI: 10.1002/path.5010] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 11/10/2017] [Accepted: 11/28/2017] [Indexed: 12/14/2022]
Abstract
The oncostatin M (OSM) receptor (OSMR) shows frequent gene copy number gains and overexpression in cervical squamous cell carcinomas (SCCs), associated with adverse clinical outcomes. In SCC cells that overexpress OSMR, the major ligand OSM induces multiple pro-malignant effects, including invasion, secretion of angiogenic factors, and metastasis. Here, we demonstrate, for the first time, that OSMR overexpression in SCC cells activates cell-autonomous feed-forward signalling, via further expression of OSMR and OSM and sustained STAT3 activation, despite expression of the negative regulator suppressor of cytokine signalling 3 (SOCS3). The pro-malignant effects associated with OSMR overexpression are critically mediated by JAK-STAT3 activation, which is induced by exogenous OSM and also by autocrine OSM-OSMR interactions. Importantly, specific inhibition of OSM-OSMR interactions by neutralizing antibodies significantly inhibits STAT3 activation and feed-forward signalling, leading to reduced invasion, angiogenesis, and metastasis. Our findings are supported by data from 1254 clinical SCC samples, in which OSMR levels correlated with multiple cognate genes, including OSM, STAT3, and downstream targets. These data strongly support the development of OSM-OSMR-blocking antibodies as biologically targeted therapies against SCCs of the cervix and other anatomical sites. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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Affiliation(s)
| | - Valtteri Tulkki
- Department of Pathology, University of Cambridge, Cambridge, UK
| | | | - Stephen Smith
- Department of Pathology, University of Cambridge, Cambridge, UK
| | - Maja Wallberg
- Department of Pathology, University of Cambridge, Cambridge, UK
| | | | | | - Jan Botthoff
- Department of Pathology, University of Cambridge, Cambridge, UK
| | | | - Katherine Hughes
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Maria M Caffarel
- Department of Pathology, University of Cambridge, Cambridge, UK.,Biodonostia Health Research Institute, San Sebastian, Spain.,IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
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18
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Marongiu L. Proportion of transcriptionally active DNA virus integrants: a meta-analysis. Future Virol 2017. [DOI: 10.2217/fvl-2017-0063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Oncoviruses are collectively responsible for over 1,000,000 new cases of cancer per year; some can integrate into the host's chromosomes. The present work was aimed at assessing the proportion of transcriptionally active viral integrants through a systematic review of the scientific publications present on the MedLine database. From the articles screened, 628 viral integrants overall were retrieved, of which 530.84 were transcriptionally active (84.53%); among the clinical samples, 264 of 323 integrants were active (81.73%). The causes for the silencing were not addressed in the articles analyzed. These findings might highlight a possible risk factor for the insurgence of cancer since some oncovirus integrants could be reactivated by stimuli of disparate nature. Further studies should address such possibility.
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Affiliation(s)
- Luigi Marongiu
- Roslin Institute, the University of Edinburgh, Easter Bush campus, EH25 9RG Edinburgh, Scotland
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19
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Playing with fire: consequences of human papillomavirus DNA replication adjacent to genetically unstable regions of host chromatin. Curr Opin Virol 2017; 26:63-68. [PMID: 28779692 DOI: 10.1016/j.coviro.2017.07.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 06/21/2017] [Accepted: 07/18/2017] [Indexed: 12/20/2022]
Abstract
Papillomaviruses are small DNA viruses that replicate persistently in the stratified epithelial surfaces of the host. They have minimal coding capacity and must hijack many cellular processes to complete their life cycle. For example, viral genomes are tethered to host chromatin to ensure that they are effectively partitioned in dividing cells, and the host DNA damage and repair pathways are usurped to replicate viral DNA in differentiated cells. These processes result in the close juxtaposition of viral DNA with host DNA that is undergoing replication stress. This could explain the propensity of oncogenic human papillomaviruses (HPVs) to accidently integrate into common fragile sites in host DNA.
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20
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Affiliation(s)
- Alison A. McBride
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Alix Warburton
- Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
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21
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Durzynska J, Lesniewicz K, Poreba E. Human papillomaviruses in epigenetic regulations. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2016; 772:36-50. [PMID: 28528689 DOI: 10.1016/j.mrrev.2016.09.006] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 09/01/2016] [Accepted: 09/17/2016] [Indexed: 12/12/2022]
Abstract
Human Papillomaviruses (HPVs) are double-stranded DNA viruses, that infect epithelial cells and are etiologically involved in the development of human cancer. Today, over 200 types of human papillomaviruses are known. They are divided into low-risk and high-risk HPVs depending on their potential to induce carcinogenesis, driven by two major viral oncoproteins, E6 and E7. By interacting with cellular partners, these proteins are involved in interdependent viral and cell cycles in stratified differentiating epithelium, and concomitantly induce epigenetic changes in infected cells and those undergoing malignant transformation. E6 and E7 oncoproteins interact with and/or modulate expression of many proteins involved in epigenetic regulation, including DNA methyltransferases, histone-modifying enzymes and subunits of chromatin remodeling complexes, thereby influencing host cell transcription program. Furthermore, HPV oncoproteins modulate expression of cellular micro RNAs. Most of these epigenetic actions in a complex dynamic interplay participate in the maintenance of persistent infection, cell transformation, and development of invasive cancer by a considerable deregulation of tumor suppressor and oncogenes. In this study, we have undertaken to discuss a number of studies concerning epigenetic regulations in HPV-dependent cells and to focus on those that have biological relevance to cancer progression.
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Affiliation(s)
- Julia Durzynska
- Department of Molecular Virology, Institute of Experimental Biology, A. Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Krzysztof Lesniewicz
- Department of Molecular and Cellular Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
| | - Elzbieta Poreba
- Department of Molecular Virology, Institute of Experimental Biology, A. Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland.
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22
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Tandemly Integrated HPV16 Can Form a Brd4-Dependent Super-Enhancer-Like Element That Drives Transcription of Viral Oncogenes. mBio 2016; 7:mBio.01446-16. [PMID: 27624132 PMCID: PMC5021809 DOI: 10.1128/mbio.01446-16] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
In cancer cells associated with human papillomavirus (HPV) infections, the viral genome is very often found integrated into the cellular genome. The viral oncogenes E6 and E7 are transcribed from the viral promoter, and integration events that alter transcriptional regulation of this promoter contribute to carcinogenic progression. In this study, we detected highly enriched binding of the super-enhancer markers Brd4, MED1, and H3K27ac, visible as a prominent nuclear focus by immunofluorescence, at the tandemly integrated copies of HPV16 in cells of the cervical neoplasia cell line W12 subclone 20861. Tumor cells are often addicted to super-enhancer-driven oncogenes and are particularly sensitive to disruption of transcription factor binding to the enhancers. Treatment of 20861 cells with bromodomain inhibitors displaced Brd4 from the HPV integration site, greatly decreased E6/E7 transcription, and inhibited cellular proliferation. Thus, Brd4 activates viral transcription at this integration site, and strong selection for E6/E7 expression can drive the formation of a super-enhancer-like element to promote oncogenesis. Oncogenic human papillomaviruses play an essential role in the development of cervical cancer, and growth of these cancer cells requires continued expression of the viral E6 and E7 oncogenes. Integration of the virus into the host genome often results in deregulation of E6 and E7 expression, which provides a selective growth advantage and increases genetic instability of infected cells. We show here that tandemly integrated copies of the viral genome can form a super-enhancer-like element that drives E6/E7 transcription. Targeted disruption of factors binding to this element decreases viral transcription and causes cell death. Thus, cancer cells that harbor integrated HPV could be targeted by therapeutics that disrupt super-enhancer function.
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