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Yang NY, Hsieh AYY, Chen Z, Campbell AR, Gadawska I, Kakkar F, Sauve L, Bitnun A, Brophy J, Murray MCM, Pick N, Krajden M, Côté HCF. Chronic and Latent Viral Infections and Leukocyte Telomere Length across the Lifespan of Female and Male Individuals Living with or without HIV. Viruses 2024; 16:755. [PMID: 38793637 PMCID: PMC11125719 DOI: 10.3390/v16050755] [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: 04/05/2024] [Revised: 05/01/2024] [Accepted: 05/01/2024] [Indexed: 05/26/2024] Open
Abstract
BACKGROUND Chronic/latent viral infections may accelerate immunological aging, particularly among people living with HIV (PLWH). We characterized chronic/latent virus infections across their lifespan and investigated their associations with leukocyte telomere length (LTL). METHODS Participants enrolled in the CARMA cohort study were randomly selected to include n = 15 for each decade of age between 0 and >60 y, for each sex, and each HIV status. Cytomegalovirus (CMV), Epstein-Barr virus (EBV), human herpesvirus 8 (HHV-8), herpes simplex virus 1 (HSV-1), and HSV-2 infection were determined serologically; HIV, hepatitis C (HCV), and hepatitis B (HBV) were self-reported. LTLs were measured using monochrome multiplex qPCR. Associations between the number of viruses, LTL, and sociodemographic factors were assessed using ordinal logistic and linear regression modeling. RESULTS The study included 187 PLWH (105 female/82 male) and 190 HIV-negative participants (105 female/84 male), ranging in age from 0.7 to 76.1 years. Living with HIV, being older, and being female were associated with harbouring a greater number of chronic/latent non-HIV viruses. Having more infections was in turn bivariately associated with a shorter LTL. In multivariable analyses, older age, living with HIV, and the female sex remained independently associated with having more infections, while having 3-4 viruses (vs. 0-2) was associated with a shorter LTL. CONCLUSIONS Our results suggest that persistent viral infections are more prevalent in PLWH and females, and that these may contribute to immunological aging. Whether this is associated with comorbidities later in life remains an important question.
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Affiliation(s)
- Nancy Yi Yang
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC V6T 1Z7, Canada; (N.Y.Y.); (A.Y.Y.H.); (M.K.)
- Centre for Blood Research, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Anthony Y. Y. Hsieh
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC V6T 1Z7, Canada; (N.Y.Y.); (A.Y.Y.H.); (M.K.)
- Centre for Blood Research, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Zhuo Chen
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 2A1, Canada
| | - Amber R. Campbell
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC V6T 1Z7, Canada; (N.Y.Y.); (A.Y.Y.H.); (M.K.)
- Women’s Health Research Institute, British Columbia Women’s Hospital and Health Centre, Vancouver, BC V6H 2N9, Canada; (L.S.); (M.C.M.M.)
- Oak Tree Clinic, BC Women’s Hospital and Health Centre, Vancouver, BC V5Z 0C9, Canada
| | - Izabella Gadawska
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC V6T 1Z7, Canada; (N.Y.Y.); (A.Y.Y.H.); (M.K.)
| | - Fatima Kakkar
- Department of Pediatrics, CHU Sainte-Justine, Université de Montréal, Montreal, QC H3T 1C5, Canada;
| | - Laura Sauve
- Women’s Health Research Institute, British Columbia Women’s Hospital and Health Centre, Vancouver, BC V6H 2N9, Canada; (L.S.); (M.C.M.M.)
- Oak Tree Clinic, BC Women’s Hospital and Health Centre, Vancouver, BC V5Z 0C9, Canada
- Department of Pediatrics, University of British Columbia, Vancouver, BC V6H 3V4, Canada
| | - Ari Bitnun
- Department of Pediatrics, Hospital for Sick Children, University of Toronto, Toronto, ON M5G 1X8, Canada;
| | - Jason Brophy
- Department of Pediatrics, Children’s Hospital of Eastern Ontario, University of Ottawa, Ottawa, ON K1H 8L1, Canada;
| | - Melanie C. M. Murray
- Women’s Health Research Institute, British Columbia Women’s Hospital and Health Centre, Vancouver, BC V6H 2N9, Canada; (L.S.); (M.C.M.M.)
- Oak Tree Clinic, BC Women’s Hospital and Health Centre, Vancouver, BC V5Z 0C9, Canada
- Department of Medicine, Division of Infectious Diseases, University of British Columbia Faculty of Medicine, Vancouver, BC V5Z 1M9, Canada
| | - Neora Pick
- Women’s Health Research Institute, British Columbia Women’s Hospital and Health Centre, Vancouver, BC V6H 2N9, Canada; (L.S.); (M.C.M.M.)
- Oak Tree Clinic, BC Women’s Hospital and Health Centre, Vancouver, BC V5Z 0C9, Canada
- Department of Medicine, Division of Infectious Diseases, University of British Columbia Faculty of Medicine, Vancouver, BC V5Z 1M9, Canada
| | - Mel Krajden
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC V6T 1Z7, Canada; (N.Y.Y.); (A.Y.Y.H.); (M.K.)
- British Columbia Center for Disease Control, Vancouver, BC V5Z 4R4, Canada
| | - Hélène C. F. Côté
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC V6T 1Z7, Canada; (N.Y.Y.); (A.Y.Y.H.); (M.K.)
- Centre for Blood Research, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
- Women’s Health Research Institute, British Columbia Women’s Hospital and Health Centre, Vancouver, BC V6H 2N9, Canada; (L.S.); (M.C.M.M.)
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Omar A, Marques N, Crawford N. Cancer and HIV: The Molecular Mechanisms of the Deadly Duo. Cancers (Basel) 2024; 16:546. [PMID: 38339297 PMCID: PMC10854577 DOI: 10.3390/cancers16030546] [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: 12/05/2023] [Revised: 01/19/2024] [Accepted: 01/23/2024] [Indexed: 02/12/2024] Open
Abstract
The immune deficiency associated with human immunodeficiency virus (HIV) infection causes a distinct increased risk of developing certain cancer types. Kaposi sarcoma (KS), invasive cervical cancer and non-Hodgkin's lymphoma (NHL) are the prominent malignancies that manifest as a result of opportunistic viral infections in patients with advanced HIV infection. Despite the implementation of antiretroviral therapy (ART), the prevalence of these acquired immunodeficiency syndrome (AIDS)-defining malignancies (ADMs) remains high in developing countries. In contrast, developed countries have experienced a steady decline in the occurrence of these cancer types. However, there has been an increased mortality rate attributed to non-ADMs. Here, we provide a review of the molecular mechanisms that are responsible for the development of ADMs and non-ADMs which occur in HIV-infected individuals. It is evident that ART alone is not sufficient to fully mitigate the potential for ADMs and non-ADMs in HIV-infected individuals. To enhance the diagnosis and treatment of both HIV and malignancies, a thorough comprehension of the mechanisms driving the development of such cancers is imperative.
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Affiliation(s)
- Aadilah Omar
- Division of Oncology, Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg 2193, South Africa
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3
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Li S, Wang M, Van Sciver N, Szymula A, Tumuluri VS, George A, Ramachandran A, Raina K, Costa CN, Zhao B, Kazemian M, Simas JP, Kaye KM. Kaposi's sarcoma herpesvirus latency-associated nuclear antigen broadly regulates viral gene expression and is essential for lytic infection. PLoS Pathog 2024; 20:e1011907. [PMID: 38232124 PMCID: PMC10793894 DOI: 10.1371/journal.ppat.1011907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 12/18/2023] [Indexed: 01/19/2024] Open
Abstract
Kaposi's sarcoma herpesvirus (KSHV) is a leading cause of malignancy in AIDS and current therapies are limited. Like all herpesviruses, KSHV infection can be latent or lytic. KSHV latency-associated nuclear antigen (LANA) is essential for viral genome persistence during latent infection. LANA also maintains latency by antagonizing expression and function of the KSHV lytic switch protein, RTA. Here, we find LANA null KSHV is not capable of lytic replication, indicating a requirement for LANA. While LANA promoted both lytic and latent gene expression in cells partially permissive for lytic infection, it repressed expression in non-permissive cells. Importantly, forced RTA expression in non-permissive cells led to induction of lytic infection and LANA switched to promote, rather than repress, most lytic viral gene expression. When basal viral gene expression levels were high, LANA promoted expression, but repressed expression at low basal levels unless RTA expression was forcibly induced. LANA's effects were broad, but virus gene specific, extending to an engineered, recombinant viral GFP under control of host EF1α promoter, but not to host EF1α. Together, these results demonstrate that, in addition to its essential role in genome maintenance, LANA broadly regulates viral gene expression, and is required for high levels of lytic gene expression during lytic infection. Strategies that target LANA are expected to abolish KSHV infection.
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Affiliation(s)
- Shijun Li
- Departments of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Virology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Mengbo Wang
- Department of Computer Science, Purdue University, West Lafayette, Indiana
| | - Nicholas Van Sciver
- Departments of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Virology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Agnieszka Szymula
- Departments of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Virology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Vinayak Sadasivam Tumuluri
- Departments of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Virology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Athira George
- Departments of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Virology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Akshaya Ramachandran
- Departments of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Virology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Komal Raina
- Departments of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Virology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Catarina N. Costa
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Avenida Professor Egas Moniz, Lisboa, Portugal
- Universidade Católica Portuguesa, Católica Medical School, Católica Biomedical Research, Palma de Cima, Portugal
| | - Bo Zhao
- Departments of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Majid Kazemian
- Department of Computer Science, Purdue University, West Lafayette, Indiana
- Department of Biochemistry, Purdue University, West Lafayette, Indiana
| | - J. Pedro Simas
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Avenida Professor Egas Moniz, Lisboa, Portugal
- Universidade Católica Portuguesa, Católica Medical School, Católica Biomedical Research, Palma de Cima, Portugal
| | - Kenneth M. Kaye
- Departments of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
- Program in Virology, Harvard Medical School, Boston, Massachusetts, United States of America
- Broad Institute of Harvard University and Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
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4
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Schulz TF, Freise A, Stein SC. Kaposi sarcoma-associated herpesvirus latency-associated nuclear antigen: more than a key mediator of viral persistence. Curr Opin Virol 2023; 61:101336. [PMID: 37331160 DOI: 10.1016/j.coviro.2023.101336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 05/03/2023] [Accepted: 05/22/2023] [Indexed: 06/20/2023]
Abstract
Kaposi sarcoma-associated herpesvirus (KSHV), or human herpesvirus-8, is an oncogenic herpesvirus. Its latency-associated nuclear antigen (LANA) is essential for the persistence of KSHV in latently infected cells. LANA mediates replication of the latent viral genome during the S phase of a dividing cell and partitions episomes to daughter cells by attaching them to mitotic chromosomes. It also mediates the establishment of latency in newly infected cells through epigenetic mechanisms and suppresses the activation of the productive replication cycle. Furthermore, LANA promotes the proliferation of infected cell by acting as a transcriptional regulator and by modulating the cellular proteome through the recruitment of several cellular ubiquitin ligases. Finally, LANA interferes with the innate and adaptive immune system to facilitate the immune escape of infected cells.
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Affiliation(s)
- Thomas F Schulz
- Institute of Virology, Hannover Medical School, Germany; Cluster of Excellence 2155 RESIST, Germany; German Center for Infection Research, Hannover-Braunschweig Site, Germany.
| | - Anika Freise
- Institute of Virology, Hannover Medical School, Germany
| | - Saskia C Stein
- Institute of Virology, Hannover Medical School, Germany; Cluster of Excellence 2155 RESIST, Germany
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5
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Luo T, Pan Y, Liu Y, Zheng J, Zhuang Z, Ren Z, Zhu J, Gu Y, Zeng Y. LANA regulates miR-155/GATA3 signaling axis by enhancing c-Jun/c-Fos interaction to promote the proliferation and migration of KSHV-infected cells. J Med Virol 2023; 95:e28255. [PMID: 36284455 DOI: 10.1002/jmv.28255] [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: 07/19/2022] [Revised: 10/08/2022] [Accepted: 10/21/2022] [Indexed: 01/11/2023]
Abstract
Kaposi's sarcoma (KS) is the second most common tumor in people infected with human immunodeficiency virus worldwide, but its pathogenesis is still unclear. In this study, we discovered that the expression of GATA-binding protein 3 (GATA3) was lowly expressed in KS tissues and KSHV-infected cells, while microRNA-155 (miR-155) was highly expressed in KS serum and KSHV-infected cells. miR-155 promoted the proliferation, migration and invasion of KSHV infection by targeting GATA3. Further, The KSHV-encoded protein, the Latency associated nuclear antigen (LANA), promotes the proliferation, migration and invasion of KSHV-infected cells by regulating the miR-155/GATA3 axis. Regarding the molecular mechanism, c-Jun and c-Fos interact to form a complex. LANA upregulates the expression of c-Jun and c-Fos and enhances the formation of c-Jun/c-Fos complex. The complex binds to the -95∼-100 bp site of miR-155 promoter and transcriptionally activates miR-155. All in all, LANA enhances the c-Jun/c-Fos interaction, resulting in enhanced transcriptional regulation of miR-155 by the c-Jun/c-Fos complex, thereby downregulating GATA3 and promoting the proliferation, migration and invasion of KSHV-infected cells. The discovery of LANA/c-Jun/c-Fos/miR-155/GATA3 further refines the pathogenesis of KS, potentially opening a new avenue for developing effective drugs against KS.
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Affiliation(s)
- Ting Luo
- Precision Clinical Laboratory, Central People's Hospital of Zhanjiang, Zhanjiang, Guangdong, China.,Key Laboratory of Xinjiang Endemic and Ethnic Disease, School of Medicine, Shihezi University, Shihezi, Xinjiang, China
| | - Yangyang Pan
- Precision Clinical Laboratory, Central People's Hospital of Zhanjiang, Zhanjiang, Guangdong, China.,Key Laboratory of Xinjiang Endemic and Ethnic Disease, School of Medicine, Shihezi University, Shihezi, Xinjiang, China
| | - Yuhao Liu
- Beijing Key Laboratory for Radiobiology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Jun Zheng
- Key Laboratory of Xinjiang Endemic and Ethnic Disease, School of Medicine, Shihezi University, Shihezi, Xinjiang, China
| | - Zhaowei Zhuang
- Key Laboratory of Xinjiang Endemic and Ethnic Disease, School of Medicine, Shihezi University, Shihezi, Xinjiang, China
| | - Zuodong Ren
- Key Laboratory of Xinjiang Endemic and Ethnic Disease, School of Medicine, Shihezi University, Shihezi, Xinjiang, China
| | - Jiaojiao Zhu
- Beijing Key Laboratory for Radiobiology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Yongqing Gu
- Beijing Key Laboratory for Radiobiology, Beijing Institute of Radiation Medicine, Beijing, China
| | - Yan Zeng
- Precision Clinical Laboratory, Central People's Hospital of Zhanjiang, Zhanjiang, Guangdong, China.,Key Laboratory of Xinjiang Endemic and Ethnic Disease, School of Medicine, Shihezi University, Shihezi, Xinjiang, China
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6
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Tornesello ML, Cerasuolo A, Starita N, Tornesello AL, Bonelli P, Tuccillo FM, Buonaguro L, Isaguliants MG, Buonaguro FM. The Molecular Interplay between Human Oncoviruses and Telomerase in Cancer Development. Cancers (Basel) 2022; 14:5257. [PMID: 36358677 PMCID: PMC9659228 DOI: 10.3390/cancers14215257] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 10/21/2022] [Accepted: 10/22/2022] [Indexed: 08/29/2023] Open
Abstract
Human oncoviruses are able to subvert telomerase function in cancer cells through multiple strategies. The activity of the catalytic subunit of telomerase (TERT) is universally enhanced in virus-related cancers. Viral oncoproteins, such as high-risk human papillomavirus (HPV) E6, Epstein-Barr virus (EBV) LMP1, Kaposi's sarcoma-associated herpesvirus (HHV-8) LANA, hepatitis B virus (HBV) HBVx, hepatitis C virus (HCV) core protein and human T-cell leukemia virus-1 (HTLV-1) Tax protein, interact with regulatory elements in the infected cells and contribute to the transcriptional activation of TERT gene. Specifically, viral oncoproteins have been shown to bind TERT promoter, to induce post-transcriptional alterations of TERT mRNA and to cause epigenetic modifications, which have important effects on the regulation of telomeric and extra-telomeric functions of the telomerase. Other viruses, such as herpesviruses, operate by integrating their genomes within the telomeres or by inducing alternative lengthening of telomeres (ALT) in non-ALT cells. In this review, we recapitulate on recent findings on virus-telomerase/telomeres interplay and the importance of TERT-related oncogenic pathways activated by cancer-causing viruses.
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Affiliation(s)
- Maria Lina Tornesello
- Molecular Biology and Viral Oncology Unit, Istituto Nazionale Tumori IRCCS “Fondazione G. Pascale”, Via Mariano Semmola, 80131 Napoli, Italy
| | - Andrea Cerasuolo
- Molecular Biology and Viral Oncology Unit, Istituto Nazionale Tumori IRCCS “Fondazione G. Pascale”, Via Mariano Semmola, 80131 Napoli, Italy
| | - Noemy Starita
- Molecular Biology and Viral Oncology Unit, Istituto Nazionale Tumori IRCCS “Fondazione G. Pascale”, Via Mariano Semmola, 80131 Napoli, Italy
| | - Anna Lucia Tornesello
- Molecular Biology and Viral Oncology Unit, Istituto Nazionale Tumori IRCCS “Fondazione G. Pascale”, Via Mariano Semmola, 80131 Napoli, Italy
| | - Patrizia Bonelli
- Molecular Biology and Viral Oncology Unit, Istituto Nazionale Tumori IRCCS “Fondazione G. Pascale”, Via Mariano Semmola, 80131 Napoli, Italy
| | - Franca Maria Tuccillo
- Molecular Biology and Viral Oncology Unit, Istituto Nazionale Tumori IRCCS “Fondazione G. Pascale”, Via Mariano Semmola, 80131 Napoli, Italy
| | - Luigi Buonaguro
- Cancer Immunoregulation Unit, Istituto Nazionale Tumori IRCCS “Fondazione G. Pascale”, Via Mariano Semmola, 80131 Napoli, Italy
| | | | - Franco M. Buonaguro
- Molecular Biology and Viral Oncology Unit, Istituto Nazionale Tumori IRCCS “Fondazione G. Pascale”, Via Mariano Semmola, 80131 Napoli, Italy
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Jung KL, Choi UY, Park A, Foo SS, Kim S, Lee SA, Jung JU. Single-cell analysis of Kaposi's sarcoma-associated herpesvirus infection in three-dimensional air-liquid interface culture model. PLoS Pathog 2022; 18:e1010775. [PMID: 35976902 PMCID: PMC9385030 DOI: 10.1371/journal.ppat.1010775] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Accepted: 07/27/2022] [Indexed: 11/18/2022] Open
Abstract
The oral cavity is the major site for transmission of Kaposi's sarcoma-associated herpesvirus (KSHV), but how KSHV establishes infection and replication in the oral epithelia remains unclear. Here, we report a KSHV spontaneous lytic replication model using fully differentiated, three-dimensional (3D) oral epithelial organoids at an air-liquid interface (ALI). This model revealed that KSHV infected the oral epithelia when the basal epithelial cells were exposed by damage. Unlike two-dimensional (2D) cell culture, 3D oral epithelial organoid ALI culture allowed high levels of spontaneous KSHV lytic replication, where lytically replicating cells were enriched at the superficial layer of epithelial organoid. Single cell RNA sequencing (scRNAseq) showed that KSHV infection induced drastic changes of host gene expression in infected as well as uninfected cells at the different epithelial layers, resulting in altered keratinocyte differentiation and cell death. Moreover, we identified a unique population of infected cells containing lytic gene expression at the KSHV K2-K5 gene locus and distinct host gene expression compared to latent or lytic infected cells. This study demonstrates an in vitro 3D epithelial organoid ALI culture model that recapitulates KSHV infection in the oral cavity, where KSHV undergoes the epithelial differentiation-dependent spontaneous lytic replication with a unique cell population carrying distinct viral gene expression.
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Affiliation(s)
- Kyle L. Jung
- Department of Cancer Biology and Global Center for Pathogen Research and Human Health, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Un Yung Choi
- Department of Cancer Biology and Global Center for Pathogen Research and Human Health, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Angela Park
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Suan-Sin Foo
- Department of Cancer Biology and Global Center for Pathogen Research and Human Health, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Stephanie Kim
- Department of Cancer Biology and Global Center for Pathogen Research and Human Health, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Shin-Ae Lee
- Department of Cancer Biology and Global Center for Pathogen Research and Human Health, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Jae U. Jung
- Department of Cancer Biology and Global Center for Pathogen Research and Human Health, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
- Department of Molecular Microbiology and Immunology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
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Kaposi Sarcoma, a Trifecta of Pathogenic Mechanisms. Diagnostics (Basel) 2022; 12:diagnostics12051242. [PMID: 35626397 PMCID: PMC9140574 DOI: 10.3390/diagnostics12051242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 04/29/2022] [Accepted: 05/13/2022] [Indexed: 01/10/2023] Open
Abstract
Kaposi’s sarcoma is a rare disease with four known variants: classic, epidemic, endemic and iatrogenic (transplant-related), all caused by an oncogenic virus named Human Herpes Virus 8. The viral infection in itself, along with the oncogenic properties of HHV8 and with immune system dysfunction, forms the grounds on which Kaposi’s Sarcoma may develop. Infection with HHV8 occurs through saliva via close contacts, blood, blood products, solid organ donation and, rarely, vertical transmission. Chronic inflammation and oncogenesis are promoted by a mix of viral genes that directly promote cell survival and transformation or interfere with the regular cell cycle and cell signaling (of particular note: LANA-1, v-IL6, vBCL-2, vIAP, vIRF3, vGPCR, gB, K1, K8.1, K15). The most common development sites for Kaposi’s sarcoma are the skin, mucocutaneous zones, lymph nodes and visceral organs, but it can also rarely appear in the musculoskeletal system, urinary system, endocrine organs, heart or eye. Histopathologically, spindle cell proliferation with slit-like vascular spaces, plasma cell and lymphocyte infiltrate are characteristic. The clinical presentation is heterogenic depending on the variant; some patients have indolent disease and others have aggressive disease. The treatment options include highly active antiretroviral therapy, surgery, radiation therapy, chemotherapy, and immunotherapy. A literature search was carried out using the MEDLINE/PubMed, SCOPUS and Google Scholar databases with a combination of keywords with the aim to provide critical, concise, and comprehensive insights into advances in the pathogenic mechanism of Kaposi’s sarcoma.
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Jary A, Veyri M, Gothland A, Leducq V, Calvez V, Marcelin AG. Kaposi's Sarcoma-Associated Herpesvirus, the Etiological Agent of All Epidemiological Forms of Kaposi's Sarcoma. Cancers (Basel) 2021; 13:cancers13246208. [PMID: 34944828 PMCID: PMC8699694 DOI: 10.3390/cancers13246208] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 11/30/2021] [Accepted: 12/07/2021] [Indexed: 01/08/2023] Open
Abstract
Simple Summary Kaposi’s sarcoma-associated herpesvirus (KSHV) is one of the seven oncogenic viruses currently recognized by the International Agency for Research on Cancer. Its presence for Kaposi’s sarcoma development is essential and knowledge on the oncogenic process has increased since its discovery in 1994. However, some uncertainties remain to be clarified, in particular on the exact routes of transmission and disparities in KSHV seroprevalence and the prevalence of Kaposi’s sarcoma worldwide. Here, we summarized the current data on the KSHV viral particle’s structure, its genome, the replication, its seroprevalence, the viral diversity and the lytic and latent oncogenesis proteins involved in Kaposi’s sarcoma. Lastly, we reported the environmental, immunological and viral factors possibly associated with KSHV transmission that could also play a role in the development of Kaposi’s sarcoma. Abstract Kaposi’s sarcoma-associated herpesvirus (KSHV), also called human herpesvirus 8 (HHV-8), is an oncogenic virus belonging to the Herpesviridae family. The viral particle is composed of a double-stranded DNA harboring 90 open reading frames, incorporated in an icosahedral capsid and enveloped. The viral cycle is divided in the following two states: a short lytic phase, and a latency phase that leads to a persistent infection in target cells and the expression of a small number of genes, including LANA-1, v-FLIP and v-cyclin. The seroprevalence and risk factors of infection differ around the world, and saliva seems to play a major role in viral transmission. KSHV is found in all epidemiological forms of Kaposi’s sarcoma including classic, endemic, iatrogenic, epidemic and non-epidemic forms. In a Kaposi’s sarcoma lesion, KSHV is mainly in a latent state; however, a small proportion of viral particles (<5%) are in a replicative state and are reported to be potentially involved in the proliferation of neighboring cells, suggesting they have crucial roles in the process of tumorigenesis. KSHV encodes oncogenic proteins (LANA-1, v-FLIP, v-cyclin, v-GPCR, v-IL6, v-CCL, v-MIP, v-IRF, etc.) that can modulate cellular pathways in order to induce the characteristics found in all cancer, including the inhibition of apoptosis, cells’ proliferation stimulation, angiogenesis, inflammation and immune escape, and, therefore, are involved in the development of Kaposi’s sarcoma.
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Affiliation(s)
- Aude Jary
- Service de Virologie, Hôpital Pitié-Salpêtrière, AP-HP, Institut Pierre Louis d’Épidémiologie et de Santé Publique (iPLESP), INSERM, Sorbonne Université, 75013 Paris, France; (A.G.); (V.L.); (V.C.); (A.-G.M.)
- Correspondence: ; Tel.: +33-1-4217-7401
| | - Marianne Veyri
- Service d’Oncologie Médicale, Hôpitaux Universitaires Pitié Salpêtrière-Charles Foix, AP-HP, Institut Pierre Louis d’Épidémiologie et de Santé Publique (iPLESP), INSERM, Sorbonne Université, 75013 Paris, France;
| | - Adélie Gothland
- Service de Virologie, Hôpital Pitié-Salpêtrière, AP-HP, Institut Pierre Louis d’Épidémiologie et de Santé Publique (iPLESP), INSERM, Sorbonne Université, 75013 Paris, France; (A.G.); (V.L.); (V.C.); (A.-G.M.)
| | - Valentin Leducq
- Service de Virologie, Hôpital Pitié-Salpêtrière, AP-HP, Institut Pierre Louis d’Épidémiologie et de Santé Publique (iPLESP), INSERM, Sorbonne Université, 75013 Paris, France; (A.G.); (V.L.); (V.C.); (A.-G.M.)
| | - Vincent Calvez
- Service de Virologie, Hôpital Pitié-Salpêtrière, AP-HP, Institut Pierre Louis d’Épidémiologie et de Santé Publique (iPLESP), INSERM, Sorbonne Université, 75013 Paris, France; (A.G.); (V.L.); (V.C.); (A.-G.M.)
| | - Anne-Geneviève Marcelin
- Service de Virologie, Hôpital Pitié-Salpêtrière, AP-HP, Institut Pierre Louis d’Épidémiologie et de Santé Publique (iPLESP), INSERM, Sorbonne Université, 75013 Paris, France; (A.G.); (V.L.); (V.C.); (A.-G.M.)
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10
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Mechanism of Human Telomerase Reverse Transcriptase ( hTERT) Regulation and Clinical Impacts in Leukemia. Genes (Basel) 2021; 12:genes12081188. [PMID: 34440361 PMCID: PMC8392866 DOI: 10.3390/genes12081188] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/09/2021] [Accepted: 05/17/2021] [Indexed: 01/03/2023] Open
Abstract
The proliferative capacity and continuous survival of cells are highly dependent on telomerase expression and the maintenance of telomere length. For this reason, elevated expression of telomerase has been identified in virtually all cancers, including leukemias; however, it should be noted that expression of telomerase is sometimes observed later in malignant development. This time point of activation is highly dependent on the type of leukemia and its causative factors. Many recent studies in this field have contributed to the elucidation of the mechanisms by which the various forms of leukemias increase telomerase activity. These include the dysregulation of telomerase reverse transcriptase (TERT) at various levels which include transcriptional, post-transcriptional, and post-translational stages. The pathways and biological molecules involved in these processes are also being deciphered with the advent of enabling technologies such as next-generation sequencing (NGS), ribonucleic acid sequencing (RNA-Seq), liquid chromatography-mass spectrometry (LCMS/MS), and many others. It has also been established that TERT possess diagnostic value as most adult cells do not express high levels of telomerase. Indeed, studies have shown that prognosis is not favorable in patients who have leukemias expressing high levels of telomerase. Recent research has indicated that targeting of this gene is able to control the survival of malignant cells and therefore offers a potential treatment for TERT-dependent leukemias. Here we review the mechanisms of hTERT regulation and deliberate their association in malignant states of leukemic cells. Further, we also cover the clinical implications of this gene including its use in diagnostic, prognostic, and therapeutic discoveries.
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11
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Viruses and Skin Cancer. Int J Mol Sci 2021; 22:ijms22105399. [PMID: 34065594 PMCID: PMC8161099 DOI: 10.3390/ijms22105399] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/12/2021] [Accepted: 05/14/2021] [Indexed: 12/11/2022] Open
Abstract
Advances in virology and skin cancer over recent decades have produced achievements that have been recognized not only in the field of dermatology, but also in other areas of medicine. They have modified the therapeutic and preventive solutions that can be offered to some patients and represent a significant step forward in our knowledge of the biology of skin cancer. In this paper, we review the viral agents responsible for different types of skin cancer, especially for solid skin tumors. We focus on human papillomavirus and squamous cell cancers, Merkel cell polyomavirus and Merkel cell carcinoma, and human herpesvirus 8 and Kaposi’s sarcoma.
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12
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Long C, Xu QB, Ding L, Yang L, Ji W, Gao F, Ji Y. Triptolide inhibits human telomerase reverse transcriptase by downregulating translation factors SP1 and c-Myc in Epstein-Barr virus-positive B lymphocytes. Oncol Lett 2021; 21:280. [PMID: 33732356 PMCID: PMC7905526 DOI: 10.3892/ol.2021.12541] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 11/17/2020] [Indexed: 11/06/2022] Open
Abstract
Epstein-Barr virus (EBV) mainly causes infectious mononucleosis and is associated with several neoplasms, including Burkitt's lymphoma, nasopharyngeal carcinoma and lymphoproliferative disease. Human telomerase reverse transcriptase (hTERT) regulates enzymatic activity of telomerase and is closely associated with tumorigenesis and senescence evasion. Triptolide (TP) is a diterpenoid triepoxide, with a broad-spectrum anticancer and immunosuppressive bioactivity profile. The present study investigated whether TP inhibited hTERT expression and suppressed its activity. The mRNA and protein levels of hTERT were examined by reverse transcription-quantitative PCR and western blotting. The activity of hTERT promoter was determined by dual-luciferase reporter assay. Cell Counting Kit-8 assays were performed to analyze cell proliferation. The present study used EBV-positive B lymphoma cells as a model system, and the results demonstrated that TP significantly decreased hTERT transcription and protein expression. Mechanistically, TP attenuated the hTERT promoter activity by downregulating the expression levels of specificityprotein 1 and c-Myc transcription factors. Consistently, inhibition of hTERT via shRNA transfection efficiently enhanced the suppression of cell proliferation by TP. Furthermore, TP increased virus latent replication and promoted the lytic cycle of EBV in EBV-positive B lymphoma cells, increasing the number of lytic cells and inhibiting the viability of tumor cells. Taken together, the results of the present study revealed a molecular mechanism of the pharmacological inhibition of tumor cell proliferation by TP, encouraging the translation of TP-based therapeutics in EBV-positive B lymphoma treatment.
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Affiliation(s)
- Cong Long
- Clinical Laboratory, Jingjiang People's Hospital, Jingjiang, Jiangsu 214500, P.R. China
| | - Qiu-Bo Xu
- Clinical Laboratory, Jingjiang People's Hospital, Jingjiang, Jiangsu 214500, P.R. China
| | - Li Ding
- Clinical Laboratory, Jingjiang People's Hospital, Jingjiang, Jiangsu 214500, P.R. China
| | - Liu Yang
- Clinical Laboratory, Jingjiang People's Hospital, Jingjiang, Jiangsu 214500, P.R. China
| | - Wei Ji
- Clinical Laboratory, Jingjiang People's Hospital, Jingjiang, Jiangsu 214500, P.R. China
| | - Feng Gao
- Department of General Surgery, Jingjiang People's Hospital, Jingjiang, Jiangsu 214500, P.R. China
| | - Yong Ji
- Department of General Surgery, Jingjiang People's Hospital, Jingjiang, Jiangsu 214500, P.R. China
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13
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Salimi-Jeda A, Badrzadeh F, Esghaei M, Abdoli A. The role of telomerase and viruses interaction in cancer development, and telomerase-dependent therapeutic approaches. Cancer Treat Res Commun 2021; 27:100323. [PMID: 33530025 DOI: 10.1016/j.ctarc.2021.100323] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/19/2021] [Accepted: 01/21/2021] [Indexed: 12/21/2022]
Abstract
Human telomerase reverse transcriptase (hTERT) is an enzyme that is critically involved in elongating and maintaining telomeres length to control cell life span and replicative potential. Telomerase activity is continuously expressed in human germ-line cells and most cancer cells, whereas it is suppressed in most somatic cells. In normal cells, by reducing telomerase activity and progressively shortening the telomeres, the cells progress to the senescence or apoptosis process. However, in cancer cells, telomere lengths remain constant due to telomerase's reactivation, and cells continue to proliferate and inhibit apoptosis, and ultimately lead to cancer development and human death due to metastasis. Studies demonstrated that several DNA and RNA oncoviruses could interact with telomerase by integrating their genome sequence within the host cell telomeres specifically. Through the activation of the hTERT promoter and lengthening the telomere, these cells contributes to cancer development. Since oncoviruses can activate telomerase and increase hTERT expression, there are several therapeutic strategies based on targeting the telomerase of cancer cells like telomerase-targeted peptide vaccines, hTERT-targeting dendritic cells (DCs), hTERT-targeting gene therapy, and hTERT-targeting CRISPR/Cas9 system that can overcome tumor-mediated toleration mechanisms and specifically apoptosis in cancer cells. This study reviews available data on the molecular structure of telomerase and the role of oncoviruses and telomerase interaction in cancer development and telomerase-dependent therapeutic approaches to conquest the cancer cells.
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Affiliation(s)
- Ali Salimi-Jeda
- Department of Virology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
| | - Fariba Badrzadeh
- Faculti of Medicine, Golestan University of Medical sciences, Golestan, Iran.
| | - Maryam Esghaei
- Department of Virology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
| | - Asghar Abdoli
- Department of Hepatitis and AIDS, Pasteur Institute of Iran, Tehran, Iran.
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14
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Lippert TP, Marzec P, Idilli AI, Sarek G, Vancevska A, Bower M, Farrell PJ, Ojala PM, Feldhahn N, Boulton SJ. Oncogenic herpesvirus KSHV triggers hallmarks of alternative lengthening of telomeres. Nat Commun 2021; 12:512. [PMID: 33479235 PMCID: PMC7820467 DOI: 10.1038/s41467-020-20819-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 12/22/2020] [Indexed: 12/25/2022] Open
Abstract
To achieve replicative immortality, cancer cells must activate telomere maintenance mechanisms to prevent telomere shortening. ~85% of cancers circumvent telomeric attrition by re-expressing telomerase, while the remaining ~15% of cancers induce alternative lengthening of telomeres (ALT), which relies on break-induced replication (BIR) and telomere recombination. Although ALT tumours were first reported over 20 years ago, the mechanism of ALT induction remains unclear and no study to date has described a cell-based model that permits the induction of ALT. Here, we demonstrate that infection with Kaposi's sarcoma herpesvirus (KSHV) induces sustained acquisition of ALT-like features in previously non-ALT cell lines. KSHV-infected cells acquire hallmarks of ALT activity that are also observed in KSHV-associated tumour biopsies. Down-regulating BIR impairs KSHV latency, suggesting that KSHV co-opts ALT for viral functionality. This study uncovers KSHV infection as a means to study telomere maintenance by ALT and reveals features of ALT in KSHV-associated tumours.
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Affiliation(s)
- Timothy P Lippert
- The Francis Crick Institute, 1 Midland Road, London, NW11AT, UK
- Department of Immunology & Inflammation, Centre for Haematology, Du Cane Road, London, W12 0NN, UK
| | - Paulina Marzec
- The Francis Crick Institute, 1 Midland Road, London, NW11AT, UK
| | - Aurora I Idilli
- The Francis Crick Institute, 1 Midland Road, London, NW11AT, UK
| | - Grzegorz Sarek
- The Francis Crick Institute, 1 Midland Road, London, NW11AT, UK
| | | | - Mark Bower
- National Centre for HIV Malignancy, Department of Oncology, Chelsea & Westminster Hospital, Fulham Road, London, SW10 9NH, UK
| | - Paul J Farrell
- Section of Virology, Department of Infectious Diseases, Imperial College London, Norfolk Place, London, W2 1PG, UK
| | - Päivi M Ojala
- Section of Virology, Department of Infectious Diseases, Imperial College London, Norfolk Place, London, W2 1PG, UK
- Translational Cancer Medicine Research Program, University of Helsinki, Haartmaninkatu 8, Helsinki, 00290, Finland
| | - Niklas Feldhahn
- Department of Immunology & Inflammation, Centre for Haematology, Du Cane Road, London, W12 0NN, UK
| | - Simon J Boulton
- The Francis Crick Institute, 1 Midland Road, London, NW11AT, UK.
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15
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Calderon A, Soldan SS, De Leo A, Deng Z, Frase DM, Anderson EM, Zhang Y, Vladimirova O, Lu F, Leung JC, Murphy ME, Lieberman PM. Identification of Mubritinib (TAK 165) as an inhibitor of KSHV driven primary effusion lymphoma via disruption of mitochondrial OXPHOS metabolism. Oncotarget 2020; 11:4224-4242. [PMID: 33245718 PMCID: PMC7679036 DOI: 10.18632/oncotarget.27815] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 10/29/2020] [Indexed: 02/07/2023] Open
Abstract
KSHV-associated cancers have poor prognoses and lack therapeutics that selectively target viral gene functions. We developed a screening campaign to identify known drugs that could be repurposed for the treatment of KSHV-associated cancers. We focused on primary effusion lymphoma (PEL), which has particularly poor treatment outcomes. We developed a luciferase reporter assay to test the ability of drugs to inhibit DNA binding of the KSHV LANA DNA binding domain (DBD). In parallel, we screened drugs for selective inhibition of a KSHV+ PEL cells. While potent hits were identified in each assay, only one hit, Mubritinib, was found to score in both assays. Mubritinib caused PEL cells to undergo cell cycle arrest with accumulation of sub-G1 population and Annexin V. Mubritinib inhibited LANA binding to KSHV terminal repeat (TR) DNA in KSHV+ PEL cells, but did not lead to KSHV lytic cycle reactivation. Mubritinib was originally identified as a receptor tyrosine kinase (RTK) inhibitor selective for HER2/ErbB2. But recent studies have revealed that Mubritinib can also inhibit the electron transport chain (ETC) complex at nanomolar concentrations. We found that other related ETC complex inhibitors (Rotenone and Deguelin) exhibited PEL cell growth inhibition while RTK inhibitors failed. Seahorse analysis demonstrated that Mubritinib selectively inhibits the maximal oxygen consumption (OCR) in PEL cells and metabolomics revealed changes in ATP/ADP and ATP/AMP ratios. These findings indicate that PEL cells are selectively sensitive to ETC complex inhibitors and provide a rationale for repurposing Mubritinib for selective treatment of PEL.
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Affiliation(s)
| | | | | | - Zhong Deng
- The Wistar Institute, Philadelphia, PA 19146, USA
| | | | | | - Yue Zhang
- The Wistar Institute, Philadelphia, PA 19146, USA
| | | | - Fang Lu
- The Wistar Institute, Philadelphia, PA 19146, USA
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16
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Role of DNA Methylation and CpG Sites in the Viral Telomerase RNA Promoter during Gallid Herpesvirus 2 Pathogenesis. J Virol 2020; 94:JVI.01488-20. [PMID: 32967954 PMCID: PMC7654267 DOI: 10.1128/jvi.01488-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 09/09/2020] [Indexed: 02/06/2023] Open
Abstract
Previous studies demonstrated that telomerase RNAs possess functions that promote tumor development independent of the telomerase complex. vTR is a herpesvirus-encoded telomerase RNA subunit that plays a crucial role in virus-induced tumorigenesis and is expressed by a robust viral promoter that is highly regulated by the c-Myc oncoprotein binding to the E-boxes. Here, we demonstrated that the DNA methylation patterns in the functional c-Myc response elements of the vTR promoter change upon reactivation from latency, and that demethylation strongly increases telomerase activity in virus-infected cells. Moreover, the introduction of mutation in the CpG dinucleotides of the c-Myc binding sites resulted in decreased vTR expression and complete abrogation of tumor formation. Our study provides further confirmation of the involvement of specific DNA methylation patterns in the regulation of vTR expression and vTR importance for virus-induced tumorigenesis. Gallid herpesvirus type 2 (GaHV-2) is an oncogenic alphaherpesvirus that induces malignant T-cell lymphoma in chicken. GaHV-2 encodes a viral telomerase RNA subunit (vTR) that plays a crucial role in virus-induced tumorigenesis, enhances telomerase activity, and possesses functions independent of the telomerase complex. vTR is driven by a robust viral promoter, highly expressed in virus-infected cells, and regulated by two c-Myc response elements (c-Myc REs). The regulatory mechanisms involved in controlling vTR and other genes during viral replication and latency remain poorly understood but are crucial to understanding this oncogenic herpesvirus. Therefore, we investigated DNA methylation patterns of CpG dinucleotides found in the vTR promoter and measured the impact of methylation on telomerase activity. We demonstrated that telomerase activity was considerably increased following viral reactivation. Furthermore, CpG sites within c-Myc REs showed specific changes in methylation after in vitro reactivation and in infected animals over time. Promoter reporter assays indicated that one of the c-Myc REs is involved in regulating vTR transcription, and that methylation strongly influenced vTR promoter activity. To study the importance of the CpG sites found in c-Myc REs in virus-induced tumorigenesis, we generated recombinant virus containing mutations in CpG sites of c-Myc REs together with the revertant virus by two-step Red-mediated mutagenesis. Introduced mutations in the vTR promoter did not affect the replication properties of the recombinant viruses in vitro. In contrast, replication of the mutant virus in infected chickens was severely impaired, and tumor formation completely abrogated. Our data provides an in-depth characterization of c-Myc oncoprotein REs and the involvement of DNA methylation in transcriptional regulation of vTR. IMPORTANCE Previous studies demonstrated that telomerase RNAs possess functions that promote tumor development independent of the telomerase complex. vTR is a herpesvirus-encoded telomerase RNA subunit that plays a crucial role in virus-induced tumorigenesis and is expressed by a robust viral promoter that is highly regulated by the c-Myc oncoprotein binding to the E-boxes. Here, we demonstrated that the DNA methylation patterns in the functional c-Myc response elements of the vTR promoter change upon reactivation from latency, and that demethylation strongly increases telomerase activity in virus-infected cells. Moreover, the introduction of mutation in the CpG dinucleotides of the c-Myc binding sites resulted in decreased vTR expression and complete abrogation of tumor formation. Our study provides further confirmation of the involvement of specific DNA methylation patterns in the regulation of vTR expression and vTR importance for virus-induced tumorigenesis.
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17
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Salavatiha Z, Soleimani-Jelodar R, Jalilvand S. The role of endogenous retroviruses-K in human cancer. Rev Med Virol 2020; 30:1-13. [PMID: 32734655 DOI: 10.1002/rmv.2142] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 06/22/2020] [Accepted: 06/23/2020] [Indexed: 12/15/2022]
Abstract
It is known that human endogenous retroviruses (HERVs) constitute almost 8% of the human genome. Although the expression of HERVs from the human genome is tightly regulated, different exogenous and endogenous factors could trigger HERV activation. Aberrant expression of different HERVs may potentially cause a variety of diseases such as neurological and autoimmune diseases as well as cancer. It is suggested that HERV-K can induce cancer through different mechanisms that are discussed. The interplay between some tumor viruses and HERV-K seems to be a key player in progression of viral-associated cancers because elevated levels of Rec and Np9 proteins are observed in several cancers. The frequent over expression of HERV proteins and some specific antibodies in cancer cells could be considered as suitable prognostic and therapeutic biomarkers in diagnosis and treatment of cancers. The expression of HERV proteins in cancers and development of immune responses against them may also be used as targets for cancer immunotherapy. Further studies are warranted to evaluate the role of HERVs in cancer formation and use of different HERV proteins in developing new diagnostic and therapeutic approaches for cancer treatments.
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Affiliation(s)
- Zahra Salavatiha
- Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Rahim Soleimani-Jelodar
- Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Somayeh Jalilvand
- Department of Virology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
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18
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Zhu Q, Ding L, Zi Z, Gao S, Wang C, Wang Y, Zhu C, Yuan Z, Wei F, Cai Q. Viral-Mediated AURKB Cleavage Promotes Cell Segregation and Tumorigenesis. Cell Rep 2020; 26:3657-3671.e5. [PMID: 30917319 DOI: 10.1016/j.celrep.2019.02.106] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Revised: 01/04/2019] [Accepted: 02/27/2019] [Indexed: 12/31/2022] Open
Abstract
Aurora kinase B (AURKB), a central regulator of chromosome segregation and cytokinesis, is aberrantly expressed in various cancer cells. However, the relationship of AURKB and oncogenic viruses in cancer progression remains unclear. Here, we reveal that N-cleaved isoforms of AURKB exist in several oncovirus-associated tumor cells and patient cancer tissues, including Kaposi's sarcoma-associated herpesvirus (KSHV), Epstein-Barr virus (EBV), and human papillomavirus virus (HPV). Mechanistically, in KSHV-infected tumor cells, the latent viral antigen LANA cleaves AURKB at Asp76 in a serine protease-dependent manner. The N'-AURKB relocalizes to the spindle pole and promotes the metaphase-to-telophase transition in mitotic cells. Introduction of N'-AURKB but not C'-AURKB promotes colony formation and malignant growth of tumor cells in vitro and in vivo using a murine xenograft model. Altogether, our findings uncover a proteolytic cleavage mechanism by which oncoviruses induce cancer cell segregation and tumorigenesis.
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Affiliation(s)
- Qing Zhu
- MOE and MOH Key Laboratory of Medical Molecular Virology, School of Basic Medicine, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Ling Ding
- MOE and MOH Key Laboratory of Medical Molecular Virology, School of Basic Medicine, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Zhenguo Zi
- ShengYushou Center of Cell Biology and Immunology, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Shujun Gao
- Hospital and Institute of Obstetrics and Gynecology, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Chong Wang
- MOE and MOH Key Laboratory of Medical Molecular Virology, School of Basic Medicine, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Yuyan Wang
- MOE and MOH Key Laboratory of Medical Molecular Virology, School of Basic Medicine, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Caixia Zhu
- MOE and MOH Key Laboratory of Medical Molecular Virology, School of Basic Medicine, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Zhenghong Yuan
- MOE and MOH Key Laboratory of Medical Molecular Virology, School of Basic Medicine, Shanghai Medical College, Fudan University, Shanghai 200032, China
| | - Fang Wei
- ShengYushou Center of Cell Biology and Immunology, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Qiliang Cai
- MOE and MOH Key Laboratory of Medical Molecular Virology, School of Basic Medicine, Shanghai Medical College, Fudan University, Shanghai 200032, China; Expert Workstation, Baoji Central Hospital, Baoji, 721008 Shaanxi Province, China.
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19
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Kaposi's Sarcoma-Associated Herpesvirus LANA Modulates the Stability of the E3 Ubiquitin Ligase RLIM. J Virol 2020; 94:JVI.01578-19. [PMID: 31801865 DOI: 10.1128/jvi.01578-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 11/26/2019] [Indexed: 11/20/2022] Open
Abstract
The Kaposi's sarcoma-associated herpesvirus (KSHV)-encoded latency-associated nuclear antigen (LANA) protein functions in latently infected cells as an essential participant in KSHV genome replication and as a driver of dysregulated cell growth. In a previous study, we have identified LANA-interacting proteins using a protein array screen. Here, we explore the effect of LANA on the stability and activity of RLIM (RING finger LIM-domain-interacting protein, encoded by the RNF12 gene), a novel LANA-interacting protein identified in that protein screen. RLIM is an E3 ubiquitin ligase that leads to the ubiquitination and degradation of several transcription regulators, such as LMO2, LMO4, LHX2, LHX3, LDB1, and the telomeric protein TRF1. Expression of LANA leads to downregulation of RLIM protein levels. This LANA-mediated RLIM degradation is blocked in the presence of the proteasome inhibitor, MG132. Therefore, the interaction between LANA and RLIM could be detected in coimmunoprecipitation assay only in the presence of MG132 to prevent RLIM degradation. A RING finger mutant RLIM is resistant to LANA-mediated degradation, suggesting that LANA promotes RLIM autoubiquitination. Interestingly, we found that LANA enhanced the degradation of some RLIM substrates, such as LDB1 and LMO2, and prevented RLIM-mediated degradation of others, such as LHX3 and TRF1. We also show that transcription regulation by RLIM substrates is modulated by LANA. RLIM substrates are assembled into multiprotein transcription regulator complexes that regulate the expression of many cellular genes. Therefore, our study identified another way KSHV can modulate cellular gene expression.IMPORTANCE E3 ubiquitin ligases mark their substrates for degradation and therefore control the cellular abundance of their substrates. RLIM is an E3 ubiquitin ligase that leads to the ubiquitination and degradation of several transcription regulators, such as LMO2, LMO4, LHX2, LHX3, LDB1, and the telomeric protein TRF1. Here, we show that the Kaposi's sarcoma-associated herpesvirus (KSHV)-encoded LANA protein enhances the ubiquitin ligase activity of RLIM, leading to enhanced RLIM autoubiquitination and degradation. Interestingly, LANA enhanced the degradation of some RLIM substrates, such as LDB1 and LMO2, and prevented RLIM-mediated degradation of others, such as LHX3 and TRF1. In agreement with protein stability of RLIM substrates, we found that LANA modulates transcription by LHX3-LDB1 complex and suggest additional ways LANA can modulate cellular gene expression. Our study adds another way a viral protein can regulate cellular protein stability, by enhancing the autoubiquitination and degradation of an E3 ubiquitin ligase.
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20
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Yan L, Majerciak V, Zheng ZM, Lan K. Towards Better Understanding of KSHV Life Cycle: from Transcription and Posttranscriptional Regulations to Pathogenesis. Virol Sin 2019; 34:135-161. [PMID: 31025296 PMCID: PMC6513836 DOI: 10.1007/s12250-019-00114-3] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 03/14/2019] [Indexed: 02/08/2023] Open
Abstract
Kaposi’s sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus-8 (HHV-8), is etiologically linked to the development of Kaposi’s sarcoma, primary effusion lymphoma, and multicentric Castleman’s disease. These malignancies often occur in immunosuppressed individuals, making KSHV infection-associated diseases an increasing global health concern with persistence of the AIDS epidemic. KSHV exhibits biphasic life cycles between latent and lytic infection and extensive transcriptional and posttranscriptional regulation of gene expression. As a member of the herpesvirus family, KSHV has evolved many strategies to evade the host immune response, which help the virus establish a successful lifelong infection. In this review, we summarize the current research status on the biology of latent and lytic viral infection, the regulation of viral life cycles and the related pathogenesis.
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Affiliation(s)
- Lijun Yan
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Vladimir Majerciak
- National Cancer Institute, National Institutes of Health, Frederick, MD, 21702, USA
| | - Zhi-Ming Zheng
- National Cancer Institute, National Institutes of Health, Frederick, MD, 21702, USA.
| | - Ke Lan
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
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Dai L, Del Valle L, Miley W, Whitby D, Ochoa AC, Flemington EK, Qin Z. Transactivation of human endogenous retrovirus K (HERV-K) by KSHV promotes Kaposi's sarcoma development. Oncogene 2018; 37:4534-4545. [PMID: 29743595 PMCID: PMC6195842 DOI: 10.1038/s41388-018-0282-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 03/23/2018] [Accepted: 04/02/2018] [Indexed: 12/16/2022]
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent of several human cancers such as Kaposi's sarcoma (KS), which represents the most common AIDS-associated malignancy that lacks effective treatment options. Despite its clear role in AIDS malignancies, the fact that only a small set of KSHV-infected patients will eventually develop these tumors implies that additional co-factors are required for the development of KSHV-related cancers. In the current study, we demonstrate for the first time that KSHV de novo infection or viral latent proteins are able to transactivate human endogenous retrovirus K (HERV-K) through a variety of cellular signaling pathways and transcriptional factors. Moreover, we found that HERV-K transactivation, particularly activation of its encoded oncogenic NP9 protein, plays an important role in KSHV pathogenesis and tumorigenesis in vitro and in vivo. Our data provide innovative insights into the mechanisms of HERV-K transactivation contributing to viral oncogenesis, which may represent a promising target for KS treatment.
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Affiliation(s)
- Lu Dai
- Department of Genetics, Louisiana State University Health Sciences Center, Louisiana Cancer Research Center, 1700 Tulane Avenue, New Orleans, LA, 70112, USA
- Department of Pediatrics, Research Center for Translational Medicine and Key Laboratory of Arrhythmias, East Hospital, Tongji University School of Medicine, 200120, Shanghai, China
| | - Luis Del Valle
- Department of Pathology, Louisiana State University Health Sciences Center, Louisiana Cancer Research Center, 1700 Tulane Avenue, New Orleans, LA, 70112, USA
| | - Wendell Miley
- Viral Oncology Section, AIDS and Cancer Virus Program, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, PO Box B, Frederick, MD, 21702, USA
| | - Denise Whitby
- Viral Oncology Section, AIDS and Cancer Virus Program, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, PO Box B, Frederick, MD, 21702, USA
| | - Augusto C Ochoa
- Department of Pediatrics, Louisiana State University Health Sciences Center, Louisiana Cancer Research Center, 1700 Tulane Avenue, New Orleans, LA, 70112, USA
| | - Erik K Flemington
- Department of Pathology, Tulane University Health Sciences Center, Tulane Cancer Center, 1700 Tulane Avenue, New Orleans, LA, 70112, USA
| | - Zhiqiang Qin
- Department of Genetics, Louisiana State University Health Sciences Center, Louisiana Cancer Research Center, 1700 Tulane Avenue, New Orleans, LA, 70112, USA.
- Department of Pediatrics, Research Center for Translational Medicine and Key Laboratory of Arrhythmias, East Hospital, Tongji University School of Medicine, 200120, Shanghai, China.
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22
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Full-Length Isoforms of Kaposi's Sarcoma-Associated Herpesvirus Latency-Associated Nuclear Antigen Accumulate in the Cytoplasm of Cells Undergoing the Lytic Cycle of Replication. J Virol 2017; 91:JVI.01532-17. [PMID: 28978712 DOI: 10.1128/jvi.01532-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 09/29/2017] [Indexed: 01/09/2023] Open
Abstract
The latency-associated nuclear antigen (LANA) of the Kaposi's sarcoma-associated herpesvirus (KSHV) performs a variety of functions to establish and maintain KSHV latency. During latency, LANA localizes to discrete punctate spots in the nucleus, where it tethers viral episomes to cellular chromatin and interacts with nuclear components to regulate cellular and viral gene expression. Using highly sensitive tyramide signal amplification, we determined that LANA localizes to the cytoplasm in different cell types undergoing the lytic cycle of replication after de novo primary infection and after spontaneous, tetradecanoyl phorbol acetate-, or open reading frame 50 (ORF50)/replication transactivator (RTA)-induced activation. We confirmed the presence of cytoplasmic LANA in a subset of cells in lytically active multicentric Castleman disease lesions. The induction of cellular migration by scratch-wounding confluent cell cultures, culturing under subconfluent conditions, or induction of cell differentiation in primary cultures upregulated the number of cells permissive for primary lytic KSHV infection. The induction of lytic replication was characterized by high-level expression of cytoplasmic LANA and nuclear ORF59, a marker of lytic replication. Subcellular fractionation studies revealed the presence of multiple isoforms of LANA in the cytoplasm of ORF50/RTA-activated Vero cells undergoing primary infection. Mass spectrometry analysis demonstrated that cytoplasmic LANA isoforms were full length, containing the N-terminal nuclear localization signal. These results suggest that trafficking of LANA to different subcellular locations is a regulated phenomenon, which allows LANA to interact with cellular components in different compartments during both the latent and the replicative stages of the KSHV life cycle.IMPORTANCE Kaposi's sarcoma-associated herpesvirus (KSHV) causes AIDS-related malignancies, including lymphomas and Kaposi's sarcoma. KSHV establishes lifelong infections using its latency-associated nuclear antigen (LANA). During latency, LANA localizes to the nucleus, where it connects viral and cellular DNA complexes and regulates gene expression, allowing the virus to maintain long-term infections. Our research shows that intact LANA traffics to the cytoplasm of cells undergoing permissive lytic infections and latently infected cells in which the virus is induced to replicate. This suggests that LANA plays important roles in the cytoplasm and nuclear compartments of the cell during different stages of the KSHV life cycle. Determining cytoplasmic function and mechanism for regulation of the nuclear localization of LANA will enhance our understanding of the biology of this virus, leading to therapeutic approaches to eliminate infection and block its pathological effects.
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Mui UN, Haley CT, Tyring SK. Viral Oncology: Molecular Biology and Pathogenesis. J Clin Med 2017; 6:E111. [PMID: 29186062 PMCID: PMC5742800 DOI: 10.3390/jcm6120111] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 11/17/2017] [Accepted: 11/22/2017] [Indexed: 02/06/2023] Open
Abstract
Oncoviruses are implicated in approximately 12% of all human cancers. A large number of the world's population harbors at least one of these oncoviruses, but only a small proportion of these individuals go on to develop cancer. The interplay between host and viral factors is a complex process that works together to create a microenvironment conducive to oncogenesis. In this review, the molecular biology and oncogenic pathways of established human oncoviruses will be discussed. Currently, there are seven recognized human oncoviruses, which include Epstein-Barr Virus (EBV), Human Papillomavirus (HPV), Hepatitis B and C viruses (HBV and HCV), Human T-cell lymphotropic virus-1 (HTLV-1), Human Herpesvirus-8 (HHV-8), and Merkel Cell Polyomavirus (MCPyV). Available and emerging therapies for these oncoviruses will be mentioned.
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Affiliation(s)
- Uyen Ngoc Mui
- Center for Clinical Studies, Houston, TX 77004, USA.
| | | | - Stephen K Tyring
- Center for Clinical Studies, Houston, TX 77004, USA.
- Department of Dermatology, University of Texas Health Science Center at Houston, Houston, TX 77004, USA.
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24
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Habison AC, de Miranda MP, Beauchemin C, Tan M, Cerqueira SA, Correia B, Ponnusamy R, Usherwood EJ, McVey CE, Simas JP, Kaye KM. Cross-species conservation of episome maintenance provides a basis for in vivo investigation of Kaposi's sarcoma herpesvirus LANA. PLoS Pathog 2017; 13:e1006555. [PMID: 28910389 PMCID: PMC5599060 DOI: 10.1371/journal.ppat.1006555] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 07/27/2017] [Indexed: 12/26/2022] Open
Abstract
Many pathogens, including Kaposi's sarcoma herpesvirus (KSHV), lack tractable small animal models. KSHV persists as a multi-copy, nuclear episome in latently infected cells. KSHV latency-associated nuclear antigen (kLANA) binds viral terminal repeat (kTR) DNA to mediate episome persistence. Model pathogen murine gammaherpesvirus 68 (MHV68) mLANA acts analogously on mTR DNA. kLANA and mLANA differ substantially in size and kTR and mTR show little sequence conservation. Here, we find kLANA and mLANA act reciprocally to mediate episome persistence of TR DNA. Further, kLANA rescued mLANA deficient MHV68, enabling a chimeric virus to establish latent infection in vivo in germinal center B cells. The level of chimeric virus in vivo latency was moderately reduced compared to WT infection, but WT or chimeric MHV68 infected cells had similar viral genome copy numbers as assessed by immunofluorescence of LANA intranuclear dots or qPCR. Thus, despite more than 60 Ma of evolutionary divergence, mLANA and kLANA act reciprocally on TR DNA, and kLANA functionally substitutes for mLANA, allowing kLANA investigation in vivo. Analogous chimeras may allow in vivo investigation of genes of other human pathogens.
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Affiliation(s)
- Aline C. Habison
- Departments of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Marta Pires de Miranda
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Chantal Beauchemin
- Departments of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Min Tan
- Departments of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Sofia A. Cerqueira
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Bruno Correia
- Instituto de Tecnologia Quimica e Bioliogica Antonio Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Rajesh Ponnusamy
- Instituto de Tecnologia Quimica e Bioliogica Antonio Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Edward J. Usherwood
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, United States of America
| | - Colin E. McVey
- Instituto de Tecnologia Quimica e Bioliogica Antonio Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - J. Pedro Simas
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
- * E-mail: (KMK); (JPS)
| | - Kenneth M. Kaye
- Departments of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail: (KMK); (JPS)
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Howard K, Cherezova L, DeMaster LK, Rose TM. ORF73 LANA homologs of RRV and MneRV2 contain an extended RGG/RG-rich nuclear and nucleolar localization signal that interacts directly with importin β1 for non-classical nuclear import. Virology 2017; 511:152-164. [PMID: 28850829 DOI: 10.1016/j.virol.2017.08.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 08/10/2017] [Accepted: 08/22/2017] [Indexed: 01/26/2023]
Abstract
The latency-associated nuclear antigens (LANA) of KSHV and macaque RFHVMn, members of the RV1 rhadinovirus lineage, are closely related with conservation of complex nuclear localization signals (NLS) containing bipartite KR-rich motifs and RG-rich domains, which interact distinctly with importins α and ß1 for nuclear import via classical and non-classical pathways, respectively. RV1 LANAs are expressed in the nucleus of latently-infected cells where they inhibit replication and establish a dominant RV1 latency. Here we show that LANA homologs of macaque RRV and MneRV2 from the more distantly-related RV2 lineage, lack the KR-rich NLS, and instead have a large RG-rich NLS with multiple RG dipeptides and a conserved RGG motif. The RG-NLS interacts uniquely with importin β1, which mediates nuclear import and accumulation of RV2 LANA in the nucleolus. The alternative nuclear import and localization of RV2 LANA homologs may contribute to the dominant RV2 lytic replication phenotype.
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Affiliation(s)
- Kellie Howard
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Global Health, University of Washington, Seattle, WA, USA.
| | - Lidia Cherezova
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Global Health, University of Washington, Seattle, WA, USA
| | - Laura K DeMaster
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Global Health, University of Washington, Seattle, WA, USA.
| | - Timothy M Rose
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA, USA; Department of Pediatrics, University of Washington, Seattle, WA, USA.
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26
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Günther T, Grundhoff A. Epigenetic manipulation of host chromatin by Kaposi sarcoma-associated herpesvirus: a tumor-promoting factor? Curr Opin Virol 2017; 26:104-111. [PMID: 28802146 DOI: 10.1016/j.coviro.2017.07.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 07/07/2017] [Accepted: 07/18/2017] [Indexed: 01/21/2023]
Abstract
Molecular and epidemiological evidence links Kaposi sarcoma-associated herpesvirus (KSHV) to a number of malignancies of endothelial or B cell origin. As for most virus-associated cancers, however, the tumor initiating and promoting events remain poorly understood. Given the emerging role of epigenetic alterations as drivers of human cancers, an interesting (and as of yet under-explored) hypothesis is that viral manipulation of host cell chromatin may contribute to the pathogenesis of KSHV-associated tumors. We here review the current knowledge regarding the interplay between KSHV-encoded factors and host chromatin and discuss how epigenetic alterations may contribute to the pathogenesis of KSHV-associated tumors.
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Affiliation(s)
- Thomas Günther
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Martinistrasse 52, 20252 Hamburg, Germany.
| | - Adam Grundhoff
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Martinistrasse 52, 20252 Hamburg, Germany.
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Nuclear Localization and Cleavage of STAT6 Is Induced by Kaposi's Sarcoma-Associated Herpesvirus for Viral Latency. PLoS Pathog 2017; 13:e1006124. [PMID: 28099521 PMCID: PMC5242515 DOI: 10.1371/journal.ppat.1006124] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 12/13/2016] [Indexed: 12/18/2022] Open
Abstract
Emerging evidence implies that STAT6 plays an important role in both the adaptive and innate immune responses to virus infection. Kaposi’s sarcoma-associated herpesvirus (KSHV) is an oncogenic γ-herpesvirus agent associated with several human malignancies, including Kaposi’s sarcoma (KS) and primary effusion lymphomas (PELs). Previously, we demonstrated that KSHV blocks IL-4-induced STAT6 phosphorylation and retains a basal IL-13/STAT6 constitutive activation for cell survival and proliferation. However, the mechanism by which KSHV regulates STAT6 remains largely unknown. Here, we found that KSHV-encoded LANA interacts with STAT6 and promotes nuclear localization of STAT6 independent of the tyrosine 641-phosphorylation state. Moreover, nuclear localization of STAT6 is also dramatically increased in KS tissue. The latent antigen LANA induces serine protease-mediated cleavage of STAT6 in the nucleus, where the cleaved STAT6 lacking transactivation domain functions as a dominant-negative regulator to repress transcription of Replication and Transcription Activator (RTA) and in turn shut off viral lytic replication. Blockade of STAT6 by small interference RNA dramatically enhances expression of RTA, and in turn reduces KSHV-infected endothelial cell growth and colony formation. Taken together, these results suggest that nuclear localization and cleavage of STAT6 is important for modulating the viral latency and pathogenesis of KSHV. STAT6, a member of the signal transducer and activator of transcription (STAT) family, has been shown to play an important role in viral infection. STAT6 activation is linked to reactivation of oncogenic herpesvirus and their associated cancers. However, the precise mechanism by which KSHV modulates STAT6 regulation remains unclear. In the present study, we demonstrate that KSHV induces nuclear localization and cleavage of STAT6 in both KSHV-infected B lymphoma and endothelial cells. Importantly, this effect is dependent on LANA (a key latent antigen) expression and leads to inhibition of viral lytic replication. Herein, we provide a previously uncharacterized description of how STAT6 plays an inhibitory role in the pathogenesis of oncogenic viruses.
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28
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Qin J, Lu C. Infection of KSHV and Interaction with HIV: The Bad Romance. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1018:237-251. [PMID: 29052142 DOI: 10.1007/978-981-10-5765-6_15] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV), namely, human herpesvirus 8 (HHV-8), is considered as the pathogen of Kaposi's sarcoma (KS), the most frequent cancer in untreated HIV-infected individuals. Patients infected with HIV have a much higher possibility developing KS than average individual. Researchers have found that HIV, which functions as a cofactor of KS, contributes a lot to the development of KS. In this article, we will give a brief introduction of KS and KSHV and how the interaction between KSHV and HIV contributes to the development of KS. Also we will take a glance at the development of treatment in KS, especially AIDS-KS.
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Affiliation(s)
- Jie Qin
- Key Laboratory of Pathogen Biology (Jiangsu Province), Nanjing Medical University, Nanjing, People's Republic of China.,Department of Microbiology, Nanjing Medical University, Nanjing, 210029, People's Republic of China
| | - Chun Lu
- Key Laboratory of Pathogen Biology (Jiangsu Province), Nanjing Medical University, Nanjing, People's Republic of China. .,Department of Microbiology, Nanjing Medical University, Nanjing, 210029, People's Republic of China.
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29
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Akram N, Imran M, Noreen M, Ahmed F, Atif M, Fatima Z, Bilal Waqar A. Oncogenic Role of Tumor Viruses in Humans. Viral Immunol 2016; 30:20-27. [PMID: 27830995 DOI: 10.1089/vim.2016.0109] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Viruses are the intracellular pathogens that reproduce only in the living cell and manipulate the cellular machinery to produce more viruses. Viral replications can affect cellular genes of the host in multiple cancerous ways. Approximately, 20% of all human oncogenesis is caused by cancer-causing viruses known as oncoviruses. Viral infection causes chronic inflammation leading to cell death, uncontrollable proliferation, and modulated expression of some of the regulatory proteins. Oncogenesis is a multistep phenomenon in which normal host cells are transformed into cancerous cells on the basis of host genetic variability. Oncogenic viruses encode genes that cause viral replication and transformation of the host cells to produce viral proteins and protein complexes. The phenomenon from basic viral infection to tumorigenesis is lengthy due to the involvement of factors like immunity complications, cellular mutations, and exposure to other cancerous agents. The viruses that are involved in human cancer development are Hepatitis B virus (HBV), Hepatitis C virus (HCV), Epstein-Barr virus (EBV), Human papilloma virus (HPV), Kaposi's sarcoma herpes virus (KSHV), and Human T lymphotrophic virus 1 (HTLV-1). This review article summarizes advanced knowledge related to human oncogenic viruses and the molecular mechanisms that lead to tumorigenesis in humans.
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Affiliation(s)
- Nimrah Akram
- 1 Department of Medical Laboratory Sciences (DMLS), Faculty of Health and Allied Sciences (FHAS), Imperial College of Business Studies (ICBS) , Lahore, Pakistan
| | - Muhammad Imran
- 1 Department of Medical Laboratory Sciences (DMLS), Faculty of Health and Allied Sciences (FHAS), Imperial College of Business Studies (ICBS) , Lahore, Pakistan
| | - Mamoona Noreen
- 2 Department of Zoology, The Women University Multan , Multan, Pakistan
| | - Fayyaz Ahmed
- 1 Department of Medical Laboratory Sciences (DMLS), Faculty of Health and Allied Sciences (FHAS), Imperial College of Business Studies (ICBS) , Lahore, Pakistan
| | - Muhammad Atif
- 1 Department of Medical Laboratory Sciences (DMLS), Faculty of Health and Allied Sciences (FHAS), Imperial College of Business Studies (ICBS) , Lahore, Pakistan
| | - Zareen Fatima
- 3 Department of Radiological Sciences and Medical Imaging (DRSMI) , FHAS, ICBS, Lahore, Pakistan
| | - Ahmed Bilal Waqar
- 1 Department of Medical Laboratory Sciences (DMLS), Faculty of Health and Allied Sciences (FHAS), Imperial College of Business Studies (ICBS) , Lahore, Pakistan
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Transcription Regulation of the Human Telomerase Reverse Transcriptase (hTERT) Gene. Genes (Basel) 2016; 7:genes7080050. [PMID: 27548225 PMCID: PMC4999838 DOI: 10.3390/genes7080050] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 07/23/2016] [Accepted: 08/01/2016] [Indexed: 12/11/2022] Open
Abstract
Embryonic stem cells and induced pluripotent stem cells have the ability to maintain their telomere length via expression of an enzymatic complex called telomerase. Similarly, more than 85%–90% of cancer cells are found to upregulate the expression of telomerase, conferring them with the potential to proliferate indefinitely. Telomerase Reverse Transcriptase (TERT), the catalytic subunit of telomerase holoenzyme, is the rate-limiting factor in reconstituting telomerase activity in vivo. To date, the expression and function of the human Telomerase Reverse Transcriptase (hTERT) gene are known to be regulated at various molecular levels (including genetic, mRNA, protein and subcellular localization) by a number of diverse factors. Among these means of regulation, transcription modulation is the most important, as evident in its tight regulation in cancer cell survival as well as pluripotent stem cell maintenance and differentiation. Here, we discuss how hTERT gene transcription is regulated, mainly focusing on the contribution of trans-acting factors such as transcription factors and epigenetic modifiers, as well as genetic alterations in hTERT proximal promoter.
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31
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Di Domenico EG, Toma L, Bordignon V, Trento E, D'Agosto G, Cordiali-Fei P, Ensoli F. Activation of DNA Damage Response Induced by the Kaposi's Sarcoma-Associated Herpes Virus. Int J Mol Sci 2016; 17:ijms17060854. [PMID: 27258263 PMCID: PMC4926388 DOI: 10.3390/ijms17060854] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 05/23/2016] [Accepted: 05/27/2016] [Indexed: 01/24/2023] Open
Abstract
The human herpes virus 8 (HHV-8), also known as Kaposi sarcoma-associated herpes virus (KSHV), can infect endothelial cells often leading to cell transformation and to the development of tumors, namely Kaposi’s sarcoma (KS), primary effusion lymphoma (PEL), and the plasmablastic variant of multicentric Castleman’s disease. KSHV is prevalent in areas such as sub-Saharan Africa and the Mediterranean region presenting distinct genotypes, which appear to be associated with differences in disease manifestation, according to geographical areas. In infected cells, KSHV persists in a latent episomal form. However, in a limited number of cells, it undergoes spontaneous lytic reactivation to ensure the production of new virions. During both the latent and the lytic cycle, KSHV is programmed to express genes which selectively modulate the DNA damage response (DDR) through the activation of the ataxia telangiectasia mutated (ATM) pathway and by phosphorylating factors associated with the DDR, including the major tumor suppressor protein p53 tumor suppressor p53. This review will focus on the interplay between the KSHV and the DDR response pathway throughout the viral lifecycle, exploring the putative molecular mechanism/s that may contribute to malignant transformation of host cells.
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Affiliation(s)
- Enea Gino Di Domenico
- Clinical Pathology and Microbiology Department, San Gallicano Institute, IRCCS, Rome 00144, Italy.
| | - Luigi Toma
- Infectious Disease Consultant, San Gallicano Institute, IRCCS, Rome 00144, Italy.
| | - Valentina Bordignon
- Clinical Pathology and Microbiology Department, San Gallicano Institute, IRCCS, Rome 00144, Italy.
| | - Elisabetta Trento
- Clinical Pathology and Microbiology Department, San Gallicano Institute, IRCCS, Rome 00144, Italy.
| | - Giovanna D'Agosto
- Clinical Pathology and Microbiology Department, San Gallicano Institute, IRCCS, Rome 00144, Italy.
| | - Paola Cordiali-Fei
- Clinical Pathology and Microbiology Department, San Gallicano Institute, IRCCS, Rome 00144, Italy.
| | - Fabrizio Ensoli
- Clinical Pathology and Microbiology Department, San Gallicano Institute, IRCCS, Rome 00144, Italy.
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32
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Wei F, Gan J, Wang C, Zhu C, Cai Q. Cell Cycle Regulatory Functions of the KSHV Oncoprotein LANA. Front Microbiol 2016; 7:334. [PMID: 27065950 PMCID: PMC4811921 DOI: 10.3389/fmicb.2016.00334] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 03/03/2016] [Indexed: 12/13/2022] Open
Abstract
Manipulation of cell cycle is a commonly employed strategy of viruses for achieving a favorable cellular environment during infection. Kaposi’s sarcoma-associated herpesvirus (KSHV), the primary etiological agent of several human malignancies including Kaposi’s sarcoma, and primary effusion lymphoma, encodes several oncoproteins that deregulate normal physiology of cell cycle machinery to persist with endothelial cells and B cells and subsequently establish a latent infection. During latency, only a small subset of viral proteins is expressed. Latency-associated nuclear antigen (LANA) is one of the latent antigens shown to be essential for transformation of endothelial cells in vitro. It has been well demonstrated that LANA is critical for the maintenance of latency, episome DNA replication, segregation and gene transcription. In this review, we summarize recent studies and address how LANA functions as an oncoprotein to steer host cell cycle-related events including proliferation and apoptosis by interacting with various cellular and viral factors, and highlight the potential therapeutic strategy of disrupting LANA-dependent signaling as targets in KSHV-associated cancers.
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Affiliation(s)
- Fang Wei
- ShengYushou Center of Cell Biology and Immunology, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University Shanghai, China
| | - Jin Gan
- MOE & MOH Key Laboratory of Medical Molecular Virology, School of Basic Medicine, Shanghai Medical College, Fudan University Shanghai, China
| | - Chong Wang
- MOE & MOH Key Laboratory of Medical Molecular Virology, School of Basic Medicine, Shanghai Medical College, Fudan University Shanghai, China
| | - Caixia Zhu
- MOE & MOH Key Laboratory of Medical Molecular Virology, School of Basic Medicine, Shanghai Medical College, Fudan University Shanghai, China
| | - Qiliang Cai
- MOE & MOH Key Laboratory of Medical Molecular Virology, School of Basic Medicine, Shanghai Medical College, Fudan University Shanghai, China
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33
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Jha HC, Banerjee S, Robertson ES. The Role of Gammaherpesviruses in Cancer Pathogenesis. Pathogens 2016; 5:pathogens5010018. [PMID: 26861404 PMCID: PMC4810139 DOI: 10.3390/pathogens5010018] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 01/27/2016] [Indexed: 12/15/2022] Open
Abstract
Worldwide, one fifth of cancers in the population are associated with viral infections. Among them, gammaherpesvirus, specifically HHV4 (EBV) and HHV8 (KSHV), are two oncogenic viral agents associated with a large number of human malignancies. In this review, we summarize the current understanding of the molecular mechanisms related to EBV and KSHV infection and their ability to induce cellular transformation. We describe their strategies for manipulating major cellular systems through the utilization of cell cycle, apoptosis, immune modulation, epigenetic modification, and altered signal transduction pathways, including NF-kB, Notch, Wnt, MAPK, TLR, etc. We also discuss the important EBV latent antigens, namely EBNA1, EBNA2, EBNA3’s and LMP’s, which are important for targeting these major cellular pathways. KSHV infection progresses through the engagement of the activities of the major latent proteins LANA, v-FLIP and v-Cyclin, and the lytic replication and transcription activator (RTA). This review is a current, comprehensive approach that describes an in-depth understanding of gammaherpes viral encoded gene manipulation of the host system through targeting important biological processes in viral-associated cancers.
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Affiliation(s)
- Hem Chandra Jha
- Department of Microbiology and Tumor Virology Program, Abramson Comprehensive Cancer Center, Perelman School of Medicine at the University of Pennsylvania, 201E Johnson Pavilion, 3610, Hamilton Walk, Philadelphia, PA 19104, USA.
| | - Shuvomoy Banerjee
- Department of Microbiology and Tumor Virology Program, Abramson Comprehensive Cancer Center, Perelman School of Medicine at the University of Pennsylvania, 201E Johnson Pavilion, 3610, Hamilton Walk, Philadelphia, PA 19104, USA.
| | - Erle S Robertson
- Department of Microbiology and Tumor Virology Program, Abramson Comprehensive Cancer Center, Perelman School of Medicine at the University of Pennsylvania, 201E Johnson Pavilion, 3610, Hamilton Walk, Philadelphia, PA 19104, USA.
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Purushothaman P, Dabral P, Gupta N, Sarkar R, Verma SC. KSHV Genome Replication and Maintenance. Front Microbiol 2016; 7:54. [PMID: 26870016 PMCID: PMC4740845 DOI: 10.3389/fmicb.2016.00054] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 01/12/2016] [Indexed: 12/04/2022] Open
Abstract
Kaposi's sarcoma associated herpesvirus (KSHV) or human herpesvirus 8 (HHV8) is a major etiological agent for multiple severe malignancies in immune-compromised patients. KSHV establishes lifetime persistence in the infected individuals and displays two distinct life cycles, generally a prolonged passive latent, and a short productive or lytic cycle. During latent phase, the viral episome is tethered to the host chromosome and replicates once during every cell division. Latency-associated nuclear antigen (LANA) is a predominant multifunctional nuclear protein expressed during latency, which plays a central role in episome tethering, replication and perpetual segregation of the episomes during cell division. LANA binds cooperatively to LANA binding sites (LBS) within the terminal repeat (TR) region of the viral episome as well as to the cellular nucleosomal proteins to tether viral episome to the host chromosome. LANA has been shown to modulate multiple cellular signaling pathways and recruits various cellular proteins such as chromatin modifying enzymes, replication factors, transcription factors, and cellular mitotic framework to maintain a successful latent infection. Although, many other regions within the KSHV genome can initiate replication, KSHV TR is important for latent DNA replication and possible segregation of the replicated episomes. Binding of LANA to LBS favors the recruitment of various replication factors to initiate LANA dependent DNA replication. In this review, we discuss the molecular mechanisms relevant to KSHV genome replication, segregation, and maintenance of latency.
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Affiliation(s)
- Pravinkumar Purushothaman
- Department of Microbiology and Immunology, School of Medicine, University of Nevada, Reno Reno, NV, USA
| | - Prerna Dabral
- Department of Microbiology and Immunology, School of Medicine, University of Nevada, Reno Reno, NV, USA
| | - Namrata Gupta
- Department of Microbiology and Immunology, School of Medicine, University of Nevada, Reno Reno, NV, USA
| | - Roni Sarkar
- Department of Microbiology and Immunology, School of Medicine, University of Nevada, Reno Reno, NV, USA
| | - Subhash C Verma
- Department of Microbiology and Immunology, School of Medicine, University of Nevada, Reno Reno, NV, USA
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Long C, Guo W, Zhou H, Wang J, Wang H, Sun X. Triptolide decreases expression of latency-associated nuclear antigen 1 and reduces viral titers in Kaposi's sarcoma-associated and herpesvirus-related primary effusion lymphoma cells. Int J Oncol 2016; 48:1519-30. [PMID: 26821279 DOI: 10.3892/ijo.2016.3353] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 01/11/2016] [Indexed: 11/06/2022] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) can establish a life-long persistence in the host after primary infection and is associated with certain malignancies, which are resistant to conventional chemotherapeutic agents with a poor prognosis. Latency-associated nuclear antigen 1 (LANA1) encoded by KSHV is essential for segregation, replication and maintenance of viral genome. In addition, LANA1 upregulates the transcriptional activity of signal transducer and activator of transcription 3 (STAT3), which plays an important role in promoting survival of KSHV-associated primary effusion lymphoma (PEL) cells. Furthermore, LANA1 mediates transcriptional modulation of KSHV and host genome in host cells. In the present study, the antitumor effect of triptolide was assessed. CCK-8 assays were performed to demonstrate that the proliferations of PEL cells were efficiently inhibited by triptolide in a dose- and time-dependent manner. Flow cytometric results indicated that triptolide induced cell cycle arrest and apoptosis. Western blot results suggested that triptolide downregulated LANA1 expression and reduced half-life of LANA1 in the KSHV-infected malignant cells. Viral titer experiments indicated that triptolide treatment impaired the number of viral DNA copies and the production of virions in BCBL-1 cells. Triptolide also suppressed STAT3 activity and inhibited secretion of IL-6 in PEL cells. In a mouse xenograft model of primary effusion lymphoma by BCBL-1 cells, triptolide treatment significantly inhibited ascites formation and diffused organ infiltration. These results indicate that triptolide impairs the expression of LANA1 and shows antitumor activity against PEL in vitro and in vivo. Triptolide may be a potential agent for treatment of PEL.
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Affiliation(s)
- Cong Long
- Department of Pathogen Biology, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei 430071, P.R. China
| | - Wei Guo
- Department of Pathology and Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei 430071, P.R. China
| | - Heng Zhou
- Department of Pathogen Biology, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei 430071, P.R. China
| | - Jingchao Wang
- Department of Pathogen Biology, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei 430071, P.R. China
| | - Huan Wang
- Department of Pathogen Biology, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei 430071, P.R. China
| | - Xiaoping Sun
- Department of Pathogen Biology, School of Basic Medical Sciences, Wuhan University, Wuhan, Hubei 430071, P.R. China
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Long C, Wang J, Guo W, Wang H, Wang C, Liu Y, Sun X. Triptolide inhibits transcription of hTERT through down-regulation of transcription factor specificity protein 1 in primary effusion lymphoma cells. Biochem Biophys Res Commun 2016; 469:87-93. [PMID: 26631963 DOI: 10.1016/j.bbrc.2015.11.076] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 11/17/2015] [Indexed: 01/23/2023]
Abstract
Primary effusion lymphoma (PEL) is a rare and aggressive non-Hodgkin's lymphoma. Human telomerase reverse transcriptase (hTERT), a key component responsible for the regulation of telomerase activity, plays important roles in cellular immortalization and cancer development. Triptolide purified from Tripterygium extracts displays a broad-spectrum bioactivity profile, including immunosuppressive, anti-inflammatory, and anti-tumor. In this study, it is investigated whether triptolide reduces hTERT expression and suppresses its activity in PEL cells. The mRNA and protein levels of hTERT were examined by real time-PCR and Western blotting, respectively. The activity of hTERT promoter was determined by Dual luciferase reporter assay. Our results demonstrated that triptolide decreased expression of hTERT at both mRNA and protein levels. Further gene sequence analysis indicated that the activity of hTERT promoter was suppressed by triptolide. Triptolide also reduced the half-time of hTERT. Additionally, triptolide inhibited the expression of transcription factor specificity protein 1(Sp1) in PEL cells. Furthermore, knock-down of Sp1 by using specific shRNAs resulted in down-regulation of hTERT transcription and protein expression levels. Inhibition of Sp1 by specific shRNAs enhanced triptolide-induced cell growth inhibition and apoptosis. Collectively, our results demonstrate that the inhibitory effect of triptolide on hTERT transcription is possibly mediated by inhibition of transcription factor Sp1 in PEL cells.
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Affiliation(s)
- Cong Long
- Department of Pathogen Biology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, PR China
| | - Jingchao Wang
- Department of Pathogen Biology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, PR China
| | - Wei Guo
- Department of Pathology and Physiology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, PR China
| | - Huan Wang
- Department of Pathogen Biology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, PR China
| | - Chao Wang
- Department of Pathogen Biology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, PR China
| | - Yu Liu
- Department of Pathogen Biology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, PR China
| | - Xiaoping Sun
- Department of Pathogen Biology, School of Basic Medical Sciences, Wuhan University, Wuhan, 430071, PR China; State Key Laboratory of Virology, Wuhan University, Wuhan, 430072, PR China.
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Li S, Tan M, Juillard F, Ponnusamy R, Correia B, Simas JP, Carrondo MA, McVey CE, Kaye KM. The Kaposi Sarcoma Herpesvirus Latency-associated Nuclear Antigen DNA Binding Domain Dorsal Positive Electrostatic Patch Facilitates DNA Replication and Episome Persistence. J Biol Chem 2015; 290:28084-28096. [PMID: 26420481 DOI: 10.1074/jbc.m115.674622] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Indexed: 12/15/2022] Open
Abstract
Kaposi sarcoma-associated herpesvirus (KSHV) has a causative role in several human malignancies. KSHV latency-associated nuclear antigen (LANA) mediates persistence of viral episomes in latently infected cells. LANA mediates KSHV DNA replication and segregates episomes to progeny nuclei. The structure of the LANA DNA binding domain was recently solved, revealing a positive electrostatic patch opposite the DNA binding surface, which is the site of BET protein binding. Here we investigate the functional role of the positive patch in LANA-mediated episome persistence. As expected, LANA mutants with alanine or glutamate substitutions in the central, peripheral, or lateral portions of the positive patch maintained the ability to bind DNA by EMSA. However, all of the substitution mutants were deficient for LANA DNA replication and episome maintenance. Mutation of the peripheral region generated the largest deficiencies. Despite these deficiencies, all positive patch mutants concentrated to dots along mitotic chromosomes in cells containing episomes, similar to LANA. The central and peripheral mutants, but not the lateral mutants, were reduced for BET protein interaction as assessed by co-immunoprecipitation. However, defects in BET protein binding were independent of episome maintenance function. Overall, the reductions in episome maintenance closely correlated with DNA replication deficiencies, suggesting that the replication defects account for the reduced episome persistence. Therefore, the electrostatic patch exerts a key role in LANA-mediated DNA replication and episome persistence and may act through a host cell partner(s) other than a BET protein or by inducing specific structures or complexes.
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Affiliation(s)
- Shijun Li
- Departments of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, 02115
| | - Min Tan
- Departments of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, 02115
| | - Franceline Juillard
- Departments of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, 02115
| | - Rajesh Ponnusamy
- Instituto de Tecnologia Quimica e Biologica, Universidade Nova de Lisboa, 2781-901 Oeiras, Portugal
| | - Bruno Correia
- Instituto de Tecnologia Quimica e Biologica, Universidade Nova de Lisboa, 2781-901 Oeiras, Portugal
| | - J Pedro Simas
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Maria A Carrondo
- Instituto de Tecnologia Quimica e Biologica, Universidade Nova de Lisboa, 2781-901 Oeiras, Portugal
| | - Colin E McVey
- Instituto de Tecnologia Quimica e Biologica, Universidade Nova de Lisboa, 2781-901 Oeiras, Portugal
| | - Kenneth M Kaye
- Departments of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, 02115.
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The Telomerase Inhibitor MST-312 Interferes with Multiple Steps in the Herpes Simplex Virus Life Cycle. J Virol 2015; 89:9804-16. [PMID: 26178994 DOI: 10.1128/jvi.01006-15] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 07/10/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The life cycle of herpes simplex virus (HSV) has the potential to be further manipulated to yield novel, more effective therapeutic treatments. Recent research has demonstrated that HSV-1 can increase telomerase activity and that expression of the catalytic component of telomerase, telomerase reverse transcriptase (TERT), alters sensitivity to HSV-dependent apoptosis. Telomerase is a cellular enzyme that synthesizes nucleotide repeats at the ends of chromosomes (telomeres), which prevents shortening of the 3' ends of DNA with each cell division. Once telomeres reach a critical length, cells undergo senescence and apoptosis. Here, we used a cell-permeable, reversible inhibitor of the telomerase enzyme, MST-312, to investigate telomerase activity during HSV infection. Human mammary epithelial cells immortalized through TERT expression and human carcinoma HEp-2 cells were infected with the KOS1.1 strain of HSV-1 in the presence of MST-312. MST-312 treatment reduced the number of cells displaying a cytopathic effect and the accumulation of immediate early and late viral proteins. Moreover, the presence of 20 μM to 100 μM MST-312 during infection led to a 2.5- to 5.5-log10 decrease in viral titers. MST-312 also inhibited the replication of HSV-2 and a recent clinical isolate of HSV-1. Additionally, we determined that MST-312 has the largest impact on viral events that take place prior to 5 h postinfection (hpi). Furthermore, MST-312 treatment inhibited virus replication, as measured by adsorption assays and quantification of genome replication. Together, these findings demonstrate that MST-312 interferes with the HSV life cycle. Further investigation into the mechanism for MST-312 is warranted and may provide novel targets for HSV therapies. IMPORTANCE Herpes simplex virus (HSV) infections can lead to cold sores, blindness, and brain damage. Identification of host factors that are important for the virus life cycle may provide novel targets for HSV antivirals. One such factor, telomerase, is the cellular enzyme that synthesizes DNA repeats at the ends of chromosomes during replication to prevent DNA shortening. In this study, we investigate role of telomerase in HSV infection. The data demonstrate that the telomerase inhibitor MST-312 suppressed HSV replication at multiple steps of viral infection.
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A Screen for Extracellular Signal-Regulated Kinase-Primed Glycogen Synthase Kinase 3 Substrates Identifies the p53 Inhibitor iASPP. J Virol 2015; 89:9232-41. [PMID: 26109723 DOI: 10.1128/jvi.01072-15] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 06/19/2015] [Indexed: 12/16/2022] Open
Abstract
UNLABELLED The Kaposi's sarcoma-associated herpesvirus (KSHV) LANA protein is essential for the replication and maintenance of virus genomes in latently KSHV-infected cells. LANA also drives dysregulated cell growth through a multiplicity of mechanisms that include altering the activity of the cellular kinases extracellular signal-regulated kinase (ERK) and glycogen synthase kinase 3 (GSK-3). To investigate the potential impact of these changes in enzyme activity, we used protein microarrays to identify cell proteins that were phosphorylated by the combination of ERK and GSK-3. The assays identified 58 potential ERK-primed GSK-3 substrates, of which 23 had evidence for in vivo phosphorylation in mass spectrometry databases. Two of these, SMAD4 and iASPP, were selected for further analysis and were confirmed as ERK-primed GSK-3 substrates. Cotransfection experiments revealed that iASPP, but not SMAD4, was targeted for degradation in the presence of GSK-3. iASPP interferes with apoptosis induced by p53 family members. To determine the importance of iASPP to KSHV-infected-cell growth, primary effusion lymphoma (PEL) cells were treated with an iASPP inhibitor in the presence or absence of the MDM2 inhibitor Nutlin-3. Drug inhibition of iASPP activity induced apoptosis in BC3 and BCBL1 PEL cells but did not induce poly(ADP-ribose) polymerase (PARP) cleavage in virus-negative BJAB cells. The effect of iASPP inhibition was additive with that of Nutlin-3. Interfering with iASPP function is therefore another mechanism that can sensitize KSHV-positive PEL cells to cell death. IMPORTANCE KSHV is associated with several malignancies, including primary effusion lymphoma (PEL). The KSHV-encoded LANA protein is multifunctional and promotes both cell growth and resistance to cell death. LANA is known to activate ERK and limit the activity of another kinase, GSK-3. To discover ways in which LANA manipulation of these two kinases might impact PEL cell survival, we screened a human protein microarray for ERK-primed GSK-3 substrates. One of the proteins identified, iASPP, showed reduced levels in the presence of GSK-3. Further, blocking iASPP activity increased cell death, particularly in p53 wild-type BC3 PEL cells.
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Bisson F, Paquet C, Bourget JM, Zaniolo K, Rochette PJ, Landreville S, Damour O, Boudreau F, Auger FA, Guérin SL, Germain L. Contribution of Sp1 to Telomerase Expression and Activity in Skin Keratinocytes Cultured With a Feeder Layer. J Cell Physiol 2015; 230:308-17. [PMID: 24962522 DOI: 10.1002/jcp.24706] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 06/20/2014] [Indexed: 12/31/2022]
Abstract
The growth of primary keratinocytes is improved by culturing them with a feeder layer. The aim of this study was to assess whether the feeder layer increases the lifespan of cultured epithelial cells by maintaining or improving telomerase activity and expression. The addition of an irradiated fibroblast feeder layer of either human or mouse origin (i3T3) helped maintain telomerase activity as well as expression of the transcription factor Sp1 in cultured keratinocytes. In contrast, senescence occurred earlier, together with a reduction of Sp1 expression and telomerase activity, in keratinocytes cultured without a feeder layer. Telomerase activity was consistently higher in keratinocytes grown on the three different feeder layers tested relative to cells grown without them. Suppression of Sp1 expression by RNA inhibition (RNAi) reduced both telomerase expression and activity in keratinocytes and also abolished their long-term growth capacity suggesting that Sp1 is a key regulator of both telomerase gene expression and cell cycle progression of primary cultured human skin keratinocytes. The results of the present study therefore suggest that the beneficial influence of the feeder layer relies on its ability to preserve telomerase activity in cultured human keratinocytes through the maintenance of stable levels of Sp1 expression.
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Affiliation(s)
- Francis Bisson
- Centre de Recherche en Organogénèse Expérimentale de l'Université Laval/LOEX, Université Laval, Québec, Canada
- Centre de Recherche FRQS du CHU de Québec, Québec, Canada
| | - Claudie Paquet
- Centre de Recherche en Organogénèse Expérimentale de l'Université Laval/LOEX, Université Laval, Québec, Canada
- Centre de Recherche FRQS du CHU de Québec, Québec, Canada
| | - Jean-Michel Bourget
- Centre de Recherche en Organogénèse Expérimentale de l'Université Laval/LOEX, Université Laval, Québec, Canada
- Centre de Recherche FRQS du CHU de Québec, Québec, Canada
| | - Karine Zaniolo
- Centre de Recherche FRQS du CHU de Québec, Québec, Canada
- CUO-Recherche, Québec, Canada
| | - Patrick J Rochette
- Centre de Recherche en Organogénèse Expérimentale de l'Université Laval/LOEX, Université Laval, Québec, Canada
- Centre de Recherche FRQS du CHU de Québec, Québec, Canada
- CUO-Recherche, Québec, Canada
- Département d'Ophtalmologie et ORL-Chirurgie Cervico-Faciale, Faculté de Médecine, Université Laval, Québec, Canada
| | - Solange Landreville
- Centre de Recherche en Organogénèse Expérimentale de l'Université Laval/LOEX, Université Laval, Québec, Canada
- Centre de Recherche FRQS du CHU de Québec, Québec, Canada
- CUO-Recherche, Québec, Canada
- Département d'Ophtalmologie et ORL-Chirurgie Cervico-Faciale, Faculté de Médecine, Université Laval, Québec, Canada
| | - Odile Damour
- Banque de Tissus et Cellules HCL, Laboratoire des Substituts Cutanés (LSC) CNRS UPR-412, Hôpital Edouard Herriot, Lyon, France
| | - François Boudreau
- Département d'Anatomie et de Biologie Cellulaire, Faculté de Médecine, Université de Sherbrooke, Sherbrooke, Canada
| | - François A Auger
- Centre de Recherche en Organogénèse Expérimentale de l'Université Laval/LOEX, Université Laval, Québec, Canada
- Centre de Recherche FRQS du CHU de Québec, Québec, Canada
- CUO-Recherche, Québec, Canada
- Département d'Ophtalmologie et ORL-Chirurgie Cervico-Faciale, Faculté de Médecine, Université Laval, Québec, Canada
- Département de Chirurgie, Faculté de Médecine, Université Laval, Québec, Canada
| | - Sylvain L Guérin
- Centre de Recherche en Organogénèse Expérimentale de l'Université Laval/LOEX, Université Laval, Québec, Canada
- Centre de Recherche FRQS du CHU de Québec, Québec, Canada
- CUO-Recherche, Québec, Canada
- Département d'Ophtalmologie et ORL-Chirurgie Cervico-Faciale, Faculté de Médecine, Université Laval, Québec, Canada
| | - Lucie Germain
- Centre de Recherche en Organogénèse Expérimentale de l'Université Laval/LOEX, Université Laval, Québec, Canada
- Centre de Recherche FRQS du CHU de Québec, Québec, Canada
- CUO-Recherche, Québec, Canada
- Département d'Ophtalmologie et ORL-Chirurgie Cervico-Faciale, Faculté de Médecine, Université Laval, Québec, Canada
- Département de Chirurgie, Faculté de Médecine, Université Laval, Québec, Canada
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Uppal T, Jha HC, Verma SC, Robertson ES. Chromatinization of the KSHV Genome During the KSHV Life Cycle. Cancers (Basel) 2015; 7:112-42. [PMID: 25594667 PMCID: PMC4381254 DOI: 10.3390/cancers7010112] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 01/07/2015] [Indexed: 12/18/2022] Open
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) belongs to the gamma herpesvirus family and is the causative agent of various lymphoproliferative diseases in humans. KSHV, like other herpesviruses, establishes life-long latent infection with the expression of a limited number of viral genes. Expression of these genes is tightly regulated by both the viral and cellular factors. Recent advancements in identifying the expression profiles of viral transcripts, using tilling arrays and next generation sequencing have identified additional coding and non-coding transcripts in the KSHV genome. Determining the functions of these transcripts will provide a better understanding of the mechanisms utilized by KSHV in altering cellular pathways involved in promoting cell growth and tumorigenesis. Replication of the viral genome is critical in maintaining the existing copies of the viral episomes during both latent and lytic phases of the viral life cycle. The replication of the viral episome is facilitated by viral components responsible for recruiting chromatin modifying enzymes and replication factors for altering the chromatin complexity and replication initiation functions, respectively. Importantly, chromatin modification of the viral genome plays a crucial role in determining whether the viral genome will persist as latent episome or undergo lytic reactivation. Additionally, chromatinization of the incoming virion DNA, which lacks chromatin structure, in the target cells during primary infection, helps in establishing latent infection. Here, we discuss the recent advancements on our understating of KSHV genome chromatinization and the consequences of chromatin modifications on viral life cycle.
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Affiliation(s)
- Timsy Uppal
- Department of Microbiology and Immunology, School of Medicine, University of Nevada, 1664 N Virginia Street, MS 320, Reno, NV 89557, USA.
| | - Hem C Jha
- Department of Microbiology and the Tumor Virology Program of the Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, 201E Johnson Pavilion, 3610 Hamilton Walk, Philadelphia, PA 19104, USA.
| | - Subhash C Verma
- Department of Microbiology and Immunology, School of Medicine, University of Nevada, 1664 N Virginia Street, MS 320, Reno, NV 89557, USA.
| | - Erle S Robertson
- Department of Microbiology and the Tumor Virology Program of the Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, 201E Johnson Pavilion, 3610 Hamilton Walk, Philadelphia, PA 19104, USA.
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Uppal T, Banerjee S, Sun Z, Verma SC, Robertson ES. KSHV LANA--the master regulator of KSHV latency. Viruses 2014; 6:4961-98. [PMID: 25514370 PMCID: PMC4276939 DOI: 10.3390/v6124961] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 12/03/2014] [Accepted: 12/05/2014] [Indexed: 12/16/2022] Open
Abstract
Kaposi's sarcoma associated herpesvirus (KSHV), like other human herpes viruses, establishes a biphasic life cycle referred to as dormant or latent, and productive or lytic phases. The latent phase is characterized by the persistence of viral episomes in a highly ordered chromatin structure and with the expression of a limited number of viral genes. Latency Associated Nuclear Antigen (LANA) is among the most abundantly expressed proteins during latency and is required for various nuclear functions including the recruitment of cellular machineries for viral DNA replication and segregation of the replicated genomes to daughter cells. LANA achieves these functions by recruiting cellular proteins including replication factors, chromatin modifying enzymes and cellular mitotic apparatus assembly. LANA directly binds to the terminal repeat region of the viral genome and associates with nucleosomal proteins to tether to the host chromosome. Binding of LANA to TR recruits the replication machinery, thereby initiating DNA replication within the TR. However, other regions of the viral genome can also initiate replication as determined by Single Molecule Analysis of the Replicated DNA (SMARD) approach. Recent, next generation sequence analysis of the viral transcriptome shows the expression of additional genes during latent phase. Here, we discuss the newly annotated latent genes and the role of major latent proteins in KSHV biology.
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Affiliation(s)
- Timsy Uppal
- Department of Microbiology and Immunology, University of Nevada, Reno, School of Medicine, 1664 N Virginia Street, MS 320, Reno, NV 89557, USA.
| | - Sagarika Banerjee
- Department of Microbiology and the Tumor Virology Program of the Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, 201E Johnson Pavilion, 3610 Hamilton Walk, Philadelphia, PA 19104, USA.
| | - Zhiguo Sun
- Department of Microbiology and the Tumor Virology Program of the Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, 201E Johnson Pavilion, 3610 Hamilton Walk, Philadelphia, PA 19104, USA.
| | - Subhash C Verma
- Department of Microbiology and Immunology, University of Nevada, Reno, School of Medicine, 1664 N Virginia Street, MS 320, Reno, NV 89557, USA.
| | - Erle S Robertson
- Department of Microbiology and the Tumor Virology Program of the Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, 201E Johnson Pavilion, 3610 Hamilton Walk, Philadelphia, PA 19104, USA.
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Mesri EA, Feitelson MA, Munger K. Human viral oncogenesis: a cancer hallmarks analysis. Cell Host Microbe 2014; 15:266-82. [PMID: 24629334 DOI: 10.1016/j.chom.2014.02.011] [Citation(s) in RCA: 437] [Impact Index Per Article: 43.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Approximately 12% of all human cancers are caused by oncoviruses. Human viral oncogenesis is complex, and only a small percentage of the infected individuals develop cancer, often many years to decades after the initial infection. This reflects the multistep nature of viral oncogenesis, host genetic variability, and the fact that viruses contribute to only a portion of the oncogenic events. In this review, the Hallmarks of Cancer framework of Hanahan and Weinberg (2000 and 2011) is used to dissect the viral, host, and environmental cofactors that contribute to the biology of multistep oncogenesis mediated by established human oncoviruses. The viruses discussed include Epstein-Barr virus (EBV), high-risk human papillomaviruses (HPVs), hepatitis B and C viruses (HBV and HCV, respectively), human T cell lymphotropic virus-1 (HTLV-1), and Kaposi's sarcoma herpesvirus (KSHV).
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Affiliation(s)
- Enrique A Mesri
- Viral Oncology Program, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA; AIDS Malignancies Scientific Working Group, Miami Center for AIDS Research, Department and Graduate Program in Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
| | - Mark A Feitelson
- Department of Biology, Temple University, Philadelphia, PA 19122, USA.
| | - Karl Munger
- Division of Infectious Diseases, Department of Medicine, Brigham and Women Hospital and Harvard Medical School, Boston, MA 02115, USA.
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Abstract
The first human tumor virus was discovered in the middle of the last century by Anthony Epstein, Bert Achong and Yvonne Barr in African pediatric patients with Burkitt's lymphoma. To date, seven viruses -EBV, KSHV, high-risk HPV, MCPV, HBV, HCV and HTLV1- have been consistently linked to different types of human cancer, and infections are estimated to account for up to 20% of all cancer cases worldwide. Viral oncogenic mechanisms generally include: generation of genomic instability, increase in the rate of cell proliferation, resistance to apoptosis, alterations in DNA repair mechanisms and cell polarity changes, which often coexist with evasion mechanisms of the antiviral immune response. Viral agents also indirectly contribute to the development of cancer mainly through immunosuppression or chronic inflammation, but also through chronic antigenic stimulation. There is also evidence that viruses can modulate the malignant properties of an established tumor. In the present work, causation criteria for viruses and cancer will be described, as well as the viral agents that comply with these criteria in human tumors, their epidemiological and biological characteristics, the molecular mechanisms by which they induce cellular transformation and their associated cancers.
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Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV; also known as human herpesvirus 8) is the etiologic agent of Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease. These cancers often occur in the context of immunosuppression, which has made KSHV-associated malignancies an increasing global health concern with the persistence of the AIDS epidemic. KSHV has also been linked to several acute inflammatory diseases. KSHV exists between a lytic and latent lifecycle, which allows the virus to transition between active replication and quiescent infection. KSHV encodes a number of proteins and small RNAs that are thought to inadvertently transform host cells while performing their functions of helping the virus persist in the infected host. KSHV also has an arsenal of components that aid the virus in evading the host immune response, which help the virus establish a successful lifelong infection. In this comprehensive chapter, we will discuss the diseases associated with KSHV infection, the biology of latent and lytic infection, and individual proteins and microRNAs that are known to contribute to host cell transformation and immune evasion.
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Affiliation(s)
- Louise Giffin
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Blossom Damania
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA; Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
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Kaposi sarcoma herpes virus latency associated nuclear antigen protein release the G2/M cell cycle blocks by modulating ATM/ATR mediated checkpoint pathway. PLoS One 2014; 9:e100228. [PMID: 24972086 PMCID: PMC4074033 DOI: 10.1371/journal.pone.0100228] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 05/24/2014] [Indexed: 11/30/2022] Open
Abstract
The Kaposi's sarcoma-associated herpesvirus infects the human population and maintains latency stage of viral life cycle in a variety of cell types including cells of epithelial, mesenchymal and endothelial origin. The establishment of latent infection by KSHV requires the expression of an unique repertoire of genes among which latency associated nuclear antigen (LANA) plays a critical role in the replication of the viral genome. LANA regulates the transcription of a number of viral and cellular genes essential for the survival of the virus in the host cell. The present study demonstrates the disruption of the host G2/M cell cycle checkpoint regulation as an associated function of LANA. DNA profile of LANA expressing human B-cells demonstrated the ability of this nuclear antigen in relieving the drug (Nocodazole) induced G2/M checkpoint arrest. Caffeine suppressed nocodazole induced G2/M arrest indicating involvement of the ATM/ATR. Notably, we have also shown the direct interaction of LANA with Chk2, the ATM/ATR signalling effector and is responsible for the release of the G2/M cell cycle block.
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Wen VW, MacKenzie KL. Modeling human endothelial cell transformation in vascular neoplasias. Dis Model Mech 2014; 6:1066-79. [PMID: 24046386 PMCID: PMC3759327 DOI: 10.1242/dmm.012674] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Endothelial cell (EC)-derived neoplasias range from benign hemangioma to aggressive metastatic angiosarcoma, which responds poorly to current treatments and has a very high mortality rate. The development of treatments that are more effective for these disorders will be expedited by insight into the processes that promote abnormal proliferation and malignant transformation of human ECs. The study of primary endothelial malignancy has been limited by the rarity of the disease; however, there is potential for carefully characterized EC lines and animal models to play a central role in the discovery, development and testing of molecular targeted therapies for vascular neoplasias. This review describes molecular alterations that have been identified in EC-derived neoplasias, as well as the processes that underpin the immortalization and tumorigenic conversion of ECs. Human EC lines, established through the introduction of defined genetic elements or by culture of primary tumor tissue, are catalogued and discussed in relation to their relevance as models of vascular neoplasia.
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Affiliation(s)
- Victoria W Wen
- Cancer Cell Development Group, Children's Cancer Institute Australia for Medical Research, Lowy Cancer Research Centre, University of New South Wales, Randwick, NSW, Australia
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Kaposi's sarcoma-associated herpesvirus-encoded LANA interacts with host KAP1 to facilitate establishment of viral latency. J Virol 2014; 88:7331-44. [PMID: 24741090 DOI: 10.1128/jvi.00596-14] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
UNLABELLED Kaposi's sarcoma-associated herpesvirus (KSHV) typically displays two different phases in its life cycle, the default latent phase and the lytic phase. There is a short period of lytic gene expression in the early stage of KSHV primary infection. The factors involved in the shutdown process of lytic gene expression are poorly identified. It has been shown that the latency-associated nuclear antigen (LANA) encoded by KSHV plays an important role in the establishment of viral latency. In screening, we identified a host protein, Krüppel-associated box domain-associated protein 1 (KAP1), that bound to LANA. We validated the interaction between LANA and KAP1 in vivo and in vitro, as well as their colocalization in the nucleus. We mapped out that LANA interacted with both the N- and C-terminal domains of KAP1. Based on the interface of LANA-KAP1 interaction determined, we proved that LANA recruited KAP1 to the RTA promoter region of the KSHV genome. We revealed that KAP1 was involved in transcriptional repression by LANA. We found multiple cooccupation sites of LANA and KAP1 on the whole KSHV genome by chromatin immunoprecipitation for sequencing (ChIP-seq) and demonstrated that LANA-recruited KAP1 played a critical role in the shutdown of lytic gene expression during the early stage of KSHV primary infection. Taken together, our data suggest that LANA interacts with KAP1 and represses lytic gene expression to facilitate the establishment of KSHV latency. IMPORTANCE Our study revealed the mechanism of transcriptional repression by LANA during KSHV primary infection, providing new insights into the process of KSHV latency establishment.
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Kaposi's sarcoma-associated herpesvirus-encoded LANA can induce chromosomal instability through targeted degradation of the mitotic checkpoint kinase Bub1. J Virol 2014; 88:7367-78. [PMID: 24741095 DOI: 10.1128/jvi.00554-14] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
UNLABELLED Kaposi's sarcoma-associated herpesvirus (KSHV) has a significant contributory role in the development of three major human neoplastic or lymphoproliferative diseases: Kaposi's sarcoma (KS), primary effusion lymphoma (PEL), and multicentric Castleman's disease (MCD). These diseases are associated with chromosomal instability, a hallmark of human cancer. The latency-associated nuclear antigen (LANA) encoded by KSHV plays a key role in regulating a number of cellular pathways critical for oncogenesis. KSHV LANA alone can induce the development of B-cell hyperplasia and lymphoma in mice expressing LANA. LANA also induces chromosomal instability, thus promoting oncogenesis. However, the precise mechanism underlying LANA-mediated chromosomal instability remains uncharted. Here we report that LANA promoted the induction of chromosomal instability and the formation of micronuclei and multinucleation through its interaction with one of the critical spindle checkpoint proteins, Bub1, and the resulting degradation of Bub1. This interaction occurs through the Knl and kinase domains of Bub1, identified as important for stability and degradation. These results suggest that LANA can dysregulate Bub1 activity, which leads to aberrant chromosome replication and aneuploidy, thus contributing to KSHV-mediated oncogenesis. IMPORTANCE This work represents the first set of results identifying a novel mechanism by which LANA, a latency-associated antigen encoded by KSHV, can induce the degradation of Bub1, a spindle checkpoint protein that is important for spindle checkpoint signaling and chromosome segregation. The downregulation of Bub1 mediated by LANA resulted in chromosomal instability, a hallmark of cancer. We further investigated the specific domains of Bub1 that are required for the interaction between LANA and Bub1. The results demonstrated that the Knl and kinase domains of Bub1 are required for the interaction between LANA and Bub1. In addition, we also investigated the mechanism by which LANA promoted Bub1 degradation. Our results showed that LANA interacted physically with the anaphase-promoting complex (APC/C), thus promoting the degradation of Bub1 in a ubiquitin-dependent process.
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Site-specific association with host and viral chromatin by Kaposi's sarcoma-associated herpesvirus LANA and its reversal during lytic reactivation. J Virol 2014; 88:6762-77. [PMID: 24696474 DOI: 10.1128/jvi.00268-14] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
UNLABELLED Latency-associated nuclear antigen (LANA), a multifunctional protein expressed by the Kaposi sarcoma-associated herpesvirus (KSHV) in latently infected cells, is required for stable maintenance of the viral episome. This is mediated by two interactions: LANA binds to specific sequences (LBS1 and LBS2) on viral DNA and also engages host histones, tethering the viral genome to host chromosomes in mitosis. LANA has also been suggested to affect host gene expression, but both the mechanism(s) and role of this dysregulation in KSHV biology remain unclear. Here, we have examined LANA interactions with host chromatin on a genome-wide scale using chromatin immunoprecipitation with high-throughput sequencing (ChIP-seq) and show that LANA predominantly targets human genes near their transcriptional start sites (TSSs). These host LANA-binding sites are generally found within transcriptionally active promoters and display striking overrepresentation of a consensus DNA sequence virtually identical to the LANA-binding site 1 (LBS1) motif in KSHV DNA. Comparison of the ChIP-seq profile with whole-transcriptome (high-throughput sequencing of RNA transcripts [RNA-seq]) data reveals that few of the genes that are differentially regulated in latent infection are occupied by LANA at their promoters. This suggests that direct LANA binding to promoters is not the prime determinant of altered host transcription in KSHV-infected cells. Most surprisingly, the association of LANA to both host and viral DNA is strongly disrupted during the lytic cycle of KSHV. This disruption can be prevented by the inhibition of viral DNA synthesis, suggesting the existence of novel and potent regulatory mechanisms linked to either viral DNA replication or late gene expression. IMPORTANCE Here, we employ complementary genome-wide analyses to evaluate the distribution of the highly abundant latency-associated nuclear antigen, LANA, on the host genome and its impact on host gene expression during KSHV latent infection. Combined, ChIP-seq and RNA-seq reveal that LANA accumulates at active gene promoters that harbor specific short DNA sequences that are highly reminiscent of its cognate binding sites in the virus genome. Unexpectedly, we found that such association does not lead to remodeling of global host transcription during latency. We also report for the first time that LANA's ability to bind host and viral chromatin is highly dynamic and is disrupted in cells undergoing an extensive lytic reactivation. This therefore suggests that the association of LANA to chromatin during a productive infection cycle is controlled by a new regulatory mechanism.
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