1
|
SoRelle ED, Haynes LE, Willard KA, Chang B, Ch’ng J, Christofk H, Luftig MA. Epstein-Barr virus reactivation induces divergent abortive, reprogrammed, and host shutoff states by lytic progression. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.14.598975. [PMID: 38915538 PMCID: PMC11195279 DOI: 10.1101/2024.06.14.598975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Viral infection leads to heterogeneous cellular outcomes ranging from refractory to abortive and fully productive states. Single cell transcriptomics enables a high resolution view of these distinct post-infection states. Here, we have interrogated the host-pathogen dynamics following reactivation of Epstein-Barr virus (EBV). While benign in most people, EBV is responsible for infectious mononucleosis, up to 2% of human cancers, and is a trigger for the development of multiple sclerosis. Following latency establishment in B cells, EBV reactivates and is shed in saliva to enable infection of new hosts. Beyond its importance for transmission, the lytic cycle is also implicated in EBV-associated oncogenesis. Conversely, induction of lytic reactivation in latent EBV-positive tumors presents a novel therapeutic opportunity. Therefore, defining the dynamics and heterogeneity of EBV lytic reactivation is a high priority to better understand pathogenesis and therapeutic potential. In this study, we applied single-cell techniques to analyze diverse fate trajectories during lytic reactivation in two B cell models. Consistent with prior work, we find that cell cycle and MYC expression correlate with cells refractory to lytic reactivation. We further found that lytic induction yields a continuum from abortive to complete reactivation. Abortive lytic cells upregulate NFκB and IRF3 pathway target genes, while cells that proceed through the full lytic cycle exhibit unexpected expression of genes associated with cellular reprogramming. Distinct subpopulations of lytic cells further displayed variable profiles for transcripts known to escape virus-mediated host shutoff. These data reveal previously unknown and promiscuous outcomes of lytic reactivation with broad implications for viral replication and EBV-associated oncogenesis.
Collapse
Affiliation(s)
- Elliott D. SoRelle
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
- Duke Center for Virology, Durham, NC 27710, USA
| | - Lauren E. Haynes
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
- Duke Center for Virology, Durham, NC 27710, USA
| | - Katherine A. Willard
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
- Duke Center for Virology, Durham, NC 27710, USA
| | - Beth Chang
- Department of Integrative Immunobiology, Duke University School of Medicine, Durham, NC 27710, USA
| | - James Ch’ng
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
| | - Heather Christofk
- Department of Biological Chemistry, David Geffen School of Medicine, University of California, Los Angeles (UCLA), Los Angeles, CA 90095, USA
- Jonsson Comprehensive Cancer Center, UCLA, Los Angeles, CA 90095, USA
| | - Micah A. Luftig
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
- Duke Center for Virology, Durham, NC 27710, USA
| |
Collapse
|
2
|
Studstill CJ, Mac M, Moody CA. Interplay between the DNA damage response and the life cycle of DNA tumor viruses. Tumour Virus Res 2023; 16:200272. [PMID: 37918513 PMCID: PMC10685005 DOI: 10.1016/j.tvr.2023.200272] [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: 08/25/2023] [Revised: 10/26/2023] [Accepted: 10/29/2023] [Indexed: 11/04/2023] Open
Abstract
Approximately 20 % of human cancers are associated with virus infection. DNA tumor viruses can induce tumor formation in host cells by disrupting the cell's DNA replication and repair mechanisms. Specifically, these viruses interfere with the host cell's DNA damage response (DDR), which is a complex network of signaling pathways that is essential for maintaining the integrity of the genome. DNA tumor viruses can disrupt these pathways by expressing oncoproteins that mimic or inhibit various DDR components, thereby promoting genomic instability and tumorigenesis. Recent studies have highlighted the molecular mechanisms by which DNA tumor viruses interact with DDR components, as well as the ways in which these interactions contribute to viral replication and tumorigenesis. Understanding the interplay between DNA tumor viruses and the DDR pathway is critical for developing effective strategies to prevent and treat virally associated cancers. In this review, we discuss the current state of knowledge regarding the mechanisms by which human papillomavirus (HPV), merkel cell polyomavirus (MCPyV), Kaposi's sarcoma-associated herpesvirus (KSHV), and Epstein-Barr virus (EBV) interfere with DDR pathways to facilitate their respective life cycles, and the consequences of such interference on genomic stability and cancer development.
Collapse
Affiliation(s)
- Caleb J Studstill
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, United States
| | - Michelle Mac
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, United States
| | - Cary A Moody
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, United States; Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, United States.
| |
Collapse
|
3
|
Epstein-Barr virus protein BKRF4 restricts nucleosome assembly to suppress host antiviral responses. Proc Natl Acad Sci U S A 2022; 119:e2203782119. [PMID: 36067323 PMCID: PMC9477414 DOI: 10.1073/pnas.2203782119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Inhibition of host DNA damage response (DDR) is a common mechanism used by viruses to manipulate host cellular machinery and orchestrate viral life cycles. Epstein-Barr virus tegument protein BKRF4 associates with cellular chromatin to suppress host DDR signaling, but the underlying mechanism remains elusive. Here, we identify a BKRF4 histone binding domain (residues 15-102, termed BKRF4-HBD) that can accumulate at the DNA damage sites to disrupt 53BP1 foci formation. The high-resolution structure of the BKRF4-HBD in complex with a human H2A-H2B dimer shows that BKRF4-HBD interacts with the H2A-H2B dimer via the N-terminal region (NTR), the DWP motif (residues 80-86 containing D81, W84, P86), and the C-terminal region (CTR). The "triple-anchor" binding mode confers BKRF4-HBD the ability to associate with the partially unfolded nucleosomes, promoting the nucleosome disassembly. Importantly, disrupting the BKRF4-H2A-H2B interaction impairs the binding between BKRF4-HBD and nucleosome in vitro and inhibits the recruitment of BKRF4-HBD to DNA breaks in vivo. Together, our study reveals the structural basis of BKRF4 bindings to the partially unfolded nucleosome and elucidates an unconventional mechanism of host DDR signal attenuation.
Collapse
|
4
|
Replication Compartments-The Great Survival Strategy for Epstein-Barr Virus Lytic Replication. Microorganisms 2022; 10:microorganisms10050896. [PMID: 35630341 PMCID: PMC9144946 DOI: 10.3390/microorganisms10050896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 04/14/2022] [Accepted: 04/23/2022] [Indexed: 12/04/2022] Open
Abstract
During Epstein–Barr virus (EBV) lytic replication, viral DNA synthesis is carried out in viral replication factories called replication compartments (RCs), which are located at discrete sites in the nucleus. Viral proteins constituting the viral replication machinery are accumulated in the RCs to amplify viral genomes. Newly synthesized viral DNA is stored in a subdomain of the RC termed the BMRF1-core, matured by host factors, and finally packed into assembled viral capsids. Late (L) genes are transcribed from DNA stored in the BMRF1-core through a process that is mainly dependent on the viral pre-initiation complex (vPIC). RC formation is a well-regulated system and strongly advantageous for EBV survival because of the following aspects: (1) RCs enable the spatial separation of newly synthesized viral DNA from the cellular chromosome for protection and maturation of viral DNA; (2) EBV-coded proteins and their interaction partners are recruited to RCs, which enhances the interactions among viral proteins, cellular proteins, and viral DNA; (3) the formation of RCs benefits continuous replication, leading to L gene transcription; and (4) DNA storage and maturation leads to efficient progeny viral production. Here, we review the state of knowledge of this important viral structure and discuss its roles in EBV survival.
Collapse
|
5
|
Gilardini Montani MS, Tarquini G, Santarelli R, Gonnella R, Romeo MA, Benedetti R, Arena A, Faggioni A, Cirone M. p62/SQSTM1 promotes mitophagy and activates the NRF2-mediated anti-oxidant and anti-inflammatory response restraining EBV-driven B lymphocyte proliferation. Carcinogenesis 2021; 43:277-287. [PMID: 34958370 DOI: 10.1093/carcin/bgab116] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 11/17/2021] [Accepted: 12/01/2021] [Indexed: 11/14/2022] Open
Abstract
Reactive oxygen species (ROS) and DNA repair respectively promote and limit oncogenic transformation of B cells driven by Epstein-Barr virus (EBV). We have previously shown that EBV infection reduced autophagy in primary B lymphocytes and enhanced ROS and interleukin 6 (IL-6) release, promoting B cell proliferation and immortalization. In this study, we explored the role of p62/SQSTM1, accumulated as a consequence of autophagy reduction in EBV-infected B lymphocytes, and found that it exerted a growth suppressive effect in these cells. At molecular level, we found that p62 counteracted IL-6 production and ROS increase by interacting with NRF2 and promoting mitophagy. Moreover, p62/NRF2 axis sustained the expression level of H2AX and ataxia-telangiectasia mutated (ATM), whose activation has been shown to have growth-suppressive effects during the first steps of EBV-infection, before latency is established. In conclusion, this study shows for the first time that the accumulation of p62 and the activation of p62/axis counteracted EBV-driven proliferation of primary B lymphocytes.
Collapse
Affiliation(s)
- Maria Saveria Gilardini Montani
- Department of Experimental Medicine, "Sapienza" University of Rome, Italy, Laboratory affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Italy
| | - Greta Tarquini
- Department of Experimental Medicine, "Sapienza" University of Rome, Italy, Laboratory affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Italy
| | - Roberta Santarelli
- Department of Experimental Medicine, "Sapienza" University of Rome, Italy, Laboratory affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Italy
| | - Roberta Gonnella
- Department of Experimental Medicine, "Sapienza" University of Rome, Italy, Laboratory affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Italy
| | - Maria Anele Romeo
- Department of Experimental Medicine, "Sapienza" University of Rome, Italy, Laboratory affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Italy
| | - Rossella Benedetti
- Department of Experimental Medicine, "Sapienza" University of Rome, Italy, Laboratory affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Italy
| | - Andrea Arena
- Department of Experimental Medicine, "Sapienza" University of Rome, Italy, Laboratory affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Italy
| | - Alberto Faggioni
- Department of Experimental Medicine, "Sapienza" University of Rome, Italy, Laboratory affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Italy
| | - Mara Cirone
- Department of Experimental Medicine, "Sapienza" University of Rome, Italy, Laboratory affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Italy
| |
Collapse
|
6
|
Lee SH, Choi SJ, Choi W, Cho S, Cho M, Kim DS, Kang BW, Kim JG, Lee YM, Cho H, Kang H. Cisplatin Resistance in Epstein-Barr-Virus-Associated Gastric Carcinoma Acquired through ATM Methylation. Cancers (Basel) 2021; 13:cancers13174252. [PMID: 34503060 PMCID: PMC8428228 DOI: 10.3390/cancers13174252] [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: 07/29/2021] [Revised: 08/20/2021] [Accepted: 08/22/2021] [Indexed: 11/17/2022] Open
Abstract
Simple Summary Gastric cancer (GC) is the fifth-leading type of cancer and the third –leading cause of death from cancer. Epstein-Barr virus-associated gastric carcinoma (EBVaGC) is recently accountable for 10% of all the GC worldwide. Platinum drugs such as cisplatin and oxaliplatin are the first-line choice in GC chemotherapy. The widespread use of cisplatin leads to make tumor cells develop single or multiple drug resistance via various mechanisms. DNA hypermethylation on tumor suppressor genes is one of causes leading to drug resistances. 5-Azacytidine (5-AZA) is a chemical analogue of cytidine and inhibits DNA methyltransferase, resulting in DNA hypomethylation. Our main objective was to identify synergistic effect of two important GC drugs whose mechanisms may be in complementary cooperation. We found that cisplatin enhances its anticancer activity with 5-AZA through DNA demethylation in EBVaGC. Identifying this synergistic effect of two important GC drugs can be useful to treat EBVaGC which shows resistance to platinum-based chemotherapy. Abstract Epstein–Barr-virus-associated gastric carcinoma (EBVaGC), first reported in 1992, currently accounts for 10% of all gastric carcinoma worldwide. EBVaGC has unique DNA hypermethylation phenotypes that allow for higher proportions of DNA methylation than any other gastric cancer. CpG islands in the gene promoter region are one of the major regions in which DNA methylation controls gene transcription. Despite cisplatin-based chemotherapy being one of the standard treatment regimens for advanced gastric cancer, including EBVaGC, cisplatin alone or in combination with 5-fluorouracil has been limited by its less potent anticancer activity and the occurrence of cisplatin resistance. Accordingly, the current study evaluated the anticancer activities of a combination of cisplatin and 5-Azacytidine (5-AZA) against EBVaGC. Our findings showed that cisplatin upregulated the DNMT3A gene, whereas shRNA-targeted removal of DNMT3A mRNA contributed to cisplatin-mediated EBV lytic reactivation. Moreover, the removal of DNMT3A mRNA upregulated the ATM gene through DNA demethylation on the ATM promoter. Furthermore, CRISPR/Cas9-targeted removal of the ATM gene resulted in significantly reduced cell susceptibility and EBV lytic reactivation by a combination of cisplatin and DNMT3A inhibitor 5-AZA. Finally, 5-AZA exhibited a synergistic effect with cisplatin in anti-EBV and anti-EBVaGC activities by increasing drug susceptibility and EBV lytic reactivation. The aforementioned results suggest that cisplatin combined with DNA methylation inhibitors could be a novel therapeutic approach for EBVaGC.
Collapse
Affiliation(s)
- Sun Hee Lee
- Vessel-Organ Interaction Research Center, VOICE (MRC), Cancer Research Institute, College of Pharmacy, Kyungpook National University, Daegu 41566, Korea; (S.H.L.); (S.J.C.); (S.C.); (M.C.)
| | - Su Jin Choi
- Vessel-Organ Interaction Research Center, VOICE (MRC), Cancer Research Institute, College of Pharmacy, Kyungpook National University, Daegu 41566, Korea; (S.H.L.); (S.J.C.); (S.C.); (M.C.)
| | - Wonhyeok Choi
- Duksung Innovative Drug Center, College of Pharmacy, Duksung Women’s University, Seoul 01369, Korea;
| | - Subin Cho
- Vessel-Organ Interaction Research Center, VOICE (MRC), Cancer Research Institute, College of Pharmacy, Kyungpook National University, Daegu 41566, Korea; (S.H.L.); (S.J.C.); (S.C.); (M.C.)
| | - Miyeon Cho
- Vessel-Organ Interaction Research Center, VOICE (MRC), Cancer Research Institute, College of Pharmacy, Kyungpook National University, Daegu 41566, Korea; (S.H.L.); (S.J.C.); (S.C.); (M.C.)
| | - Dong Sun Kim
- Department of Anatomy, School of Medicine, Kyungpook National University, Daegu 41944, Korea;
| | - Byung Woog Kang
- Department of Oncology/Hematology, Cancer Research Institute, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu 41405, Korea; (B.W.K.); (J.G.K.)
| | - Jong Gwang Kim
- Department of Oncology/Hematology, Cancer Research Institute, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu 41405, Korea; (B.W.K.); (J.G.K.)
| | - You Mie Lee
- Vessel-Organ Interaction Research Center, VOICE (MRC), Department of Molecular Pathophysiology, College of Pharmacy, Kyungpook National University, Daegu 41566, Korea;
| | - Hyosun Cho
- Duksung Innovative Drug Center, College of Pharmacy, Duksung Women’s University, Seoul 01369, Korea;
- Correspondence: (H.C.); (H.K.); Tel.: +82-02-901-8678 (H.C.); +82-053-950-8569 (H.K.); Fax: +82-02-901-8386 (H.C.); +82-053-950-8557 (H.K.)
| | - Hyojeung Kang
- Vessel-Organ Interaction Research Center, VOICE (MRC), Cancer Research Institute, College of Pharmacy, Kyungpook National University, Daegu 41566, Korea; (S.H.L.); (S.J.C.); (S.C.); (M.C.)
- Correspondence: (H.C.); (H.K.); Tel.: +82-02-901-8678 (H.C.); +82-053-950-8569 (H.K.); Fax: +82-02-901-8386 (H.C.); +82-053-950-8557 (H.K.)
| |
Collapse
|
7
|
Buschle A, Mrozek-Gorska P, Cernilogar FM, Ettinger A, Pich D, Krebs S, Mocanu B, Blum H, Schotta G, Straub T, Hammerschmidt W. Epstein-Barr virus inactivates the transcriptome and disrupts the chromatin architecture of its host cell in the first phase of lytic reactivation. Nucleic Acids Res 2021; 49:3217-3241. [PMID: 33675667 PMCID: PMC8034645 DOI: 10.1093/nar/gkab099] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 02/01/2021] [Accepted: 02/04/2021] [Indexed: 12/13/2022] Open
Abstract
Epstein-Barr virus (EBV), a herpes virus also termed HHV 4 and the first identified human tumor virus, establishes a stable, long-term latent infection in human B cells, its preferred host. Upon induction of EBV's lytic phase, the latently infected cells turn into a virus factory, a process that is governed by EBV. In the lytic, productive phase, all herpes viruses ensure the efficient induction of all lytic viral genes to produce progeny, but certain of these genes also repress the ensuing antiviral responses of the virally infected host cells, regulate their apoptotic death or control the cellular transcriptome. We now find that EBV causes previously unknown massive and global alterations in the chromatin of its host cell upon induction of the viral lytic phase and prior to the onset of viral DNA replication. The viral initiator protein of the lytic cycle, BZLF1, binds to >105 binding sites with different sequence motifs in cellular chromatin in a concentration dependent manner implementing a binary molar switch probably to prevent noise-induced erroneous induction of EBV's lytic phase. Concomitant with DNA binding of BZLF1, silent chromatin opens locally as shown by ATAC-seq experiments, while previously wide-open cellular chromatin becomes inaccessible on a global scale within hours. While viral transcripts increase drastically, the induction of the lytic phase results in a massive reduction of cellular transcripts and a loss of chromatin-chromatin interactions of cellular promoters with their distal regulatory elements as shown in Capture-C experiments. Our data document that EBV's lytic cycle induces discrete early processes that disrupt the architecture of host cellular chromatin and repress the cellular epigenome and transcriptome likely supporting the efficient de novo synthesis of this herpes virus.
Collapse
Affiliation(s)
- Alexander Buschle
- Research Unit Gene Vectors, Helmholtz Zentrum München, German Research Center for Environmental Health and German Center for Infection Research (DZIF), Partner site Munich, Germany, Feodor-Lynen-Str. 21, D-81377 Munich, Germany
| | - Paulina Mrozek-Gorska
- Research Unit Gene Vectors, Helmholtz Zentrum München, German Research Center for Environmental Health and German Center for Infection Research (DZIF), Partner site Munich, Germany, Feodor-Lynen-Str. 21, D-81377 Munich, Germany
| | - Filippo M Cernilogar
- Division of Molecular Biology, Biomedical Center, Faculty of Medicine, Ludwig-Maximilians-Universität (LMU) München, 82152 Planegg-Martinsried, Germany
| | - Andreas Ettinger
- Institute of Epigenetics and Stem Cells, Helmholtz Zentrum München, German Research Center for Environmental Health, Feodor-Lynen-Str. 21 D-81377 Munich, Germany
| | - Dagmar Pich
- Research Unit Gene Vectors, Helmholtz Zentrum München, German Research Center for Environmental Health and German Center for Infection Research (DZIF), Partner site Munich, Germany, Feodor-Lynen-Str. 21, D-81377 Munich, Germany
| | - Stefan Krebs
- Laboratory for Functional Genome Analysis (LAFUGA), Gene Center of the Ludwig-Maximilians-Universität (LMU) München, 81377 Munich, Germany
| | - Bianca Mocanu
- Research Unit Gene Vectors, Helmholtz Zentrum München, German Research Center for Environmental Health and German Center for Infection Research (DZIF), Partner site Munich, Germany, Feodor-Lynen-Str. 21, D-81377 Munich, Germany
| | - Helmut Blum
- Laboratory for Functional Genome Analysis (LAFUGA), Gene Center of the Ludwig-Maximilians-Universität (LMU) München, 81377 Munich, Germany
| | - Gunnar Schotta
- Division of Molecular Biology, Biomedical Center, Faculty of Medicine, Ludwig-Maximilians-Universität (LMU) München, 82152 Planegg-Martinsried, Germany
| | - Tobias Straub
- Bioinformatics Unit, Biomedical Center, Ludwig-Maximilians-Universität (LMU) München, 82152 Planegg-Martinsried, Germany
| | - Wolfgang Hammerschmidt
- Research Unit Gene Vectors, Helmholtz Zentrum München, German Research Center for Environmental Health and German Center for Infection Research (DZIF), Partner site Munich, Germany, Feodor-Lynen-Str. 21, D-81377 Munich, Germany
| |
Collapse
|
8
|
Inflammasome, the Constitutive Heterochromatin Machinery, and Replication of an Oncogenic Herpesvirus. Viruses 2021; 13:v13050846. [PMID: 34066537 PMCID: PMC8148530 DOI: 10.3390/v13050846] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 05/01/2021] [Accepted: 05/03/2021] [Indexed: 02/07/2023] Open
Abstract
The success of long-term host–virus partnerships is predicated on the ability of the host to limit the destructive potential of the virus and the virus’s skill in manipulating its host to persist undetected yet replicate efficiently when needed. By mastering such skills, herpesviruses persist silently in their hosts, though perturbations in this host–virus equilibrium can result in disease. The heterochromatin machinery that tightly regulates endogenous retroviral elements and pericentromeric repeats also silences invading genomes of alpha-, beta-, and gammaherpesviruses. That said, how these viruses disrupt this constitutive heterochromatin machinery to replicate and spread, particularly in response to disparate lytic triggers, is unclear. Here, we review how the cancer-causing gammaherpesvirus Epstein–Barr virus (EBV) uses the inflammasome as a security system to alert itself of threats to its cellular home as well as to flip the virus-encoded lytic switch, allowing it to replicate and escape in response to a variety of lytic triggers. EBV provides the first example of an infectious agent able to actively exploit the inflammasome to spark its replication. Revealing an unexpected link between the inflammasome and the epigenome, this further brings insights into how the heterochromatin machinery uses differential strategies to maintain the integrity of the cellular genome whilst guarding against invading pathogens. These recent insights into EBV biology and host–viral epigenetic regulation ultimately point to the NLRP3 inflammasome as an attractive target to thwart herpesvirus reactivation.
Collapse
|
9
|
Nakamura H, Shimizu T, Kawakami A. Role of Viral Infections in the Pathogenesis of Sjögren's Syndrome: Different Characteristics of Epstein-Barr Virus and HTLV-1. J Clin Med 2020; 9:jcm9051459. [PMID: 32414149 PMCID: PMC7290771 DOI: 10.3390/jcm9051459] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 05/06/2020] [Accepted: 05/06/2020] [Indexed: 12/12/2022] Open
Abstract
Viruses are possible pathogenic agents in several autoimmune diseases. Sjögren’s syndrome (SS), which involves exocrine dysfunction and the appearance of autoantibodies, shows salivary gland- and lacrimal gland-oriented clinical features. Epstein-Barr virus (EBV) is the most investigated pathogen as a candidate that directly induces the phenotype found in SS. The reactivation of the virus with various stimuli induced a dysregulated form of EBV that has the potential to infect SS-specific B cells and plasma cells that are closely associated with the function of an ectopic lymphoid structure that contains a germinal center (GC) in the salivary glands of individuals with SS. The involvement of human T-cell leukemia virus type 1 (HTLV-1) in SS has been epidemiologically established, but the disease concept of HTLV-1-associated SS remains unexplained due to limited evidence from basic research. Unlike the cell-to-cell contact between lymphocytes, biofilm-like structures are candidates as the mode of HTLV-1 infection of salivary gland epithelial cells (SGECs). HTLV-1 can infect SGECs with enhanced levels of inflammatory cytokines and chemokines that are secreted from SGECs. Regardless of the different targets that viruses have with respect to affinitive lymphocytes, viruses are involved in the formation of pathological alterations with immunological modifications in SS.
Collapse
|
10
|
Retrograde Regulation by the Viral Protein Kinase Epigenetically Sustains the Epstein-Barr Virus Latency-to-Lytic Switch To Augment Virus Production. J Virol 2019; 93:JVI.00572-19. [PMID: 31189703 DOI: 10.1128/jvi.00572-19] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 06/03/2019] [Indexed: 12/14/2022] Open
Abstract
Herpesviruses are ubiquitous, and infection by some, like Epstein-Barr virus (EBV), is nearly universal. To persist, EBV must periodically switch from a latent to a replicative/lytic phase. This productive phase is responsible for most herpesvirus-associated diseases. EBV encodes a latency-to-lytic switch protein which, upon activation, sets off a vectorially constrained cascade of gene expression that results in production of infectious virus. While triggering expression of the switch protein ZEBRA is essential to lytic cycle entry, sustaining its expression is equally important to avoid premature termination of the lytic cascade. We report that the viral protein kinase (vPK), encoded by a gene that is kinetically downstream of the lytic switch, sustains expression of ZEBRA, amplifies the lytic cascade, increasing virus production, and, importantly, prevents the abortive lytic cycle. We find that vPK, through a noncanonical site phosphorylation, activates the cellular phosphatidylinositol 3-kinase-related kinase ATM to cause phosphorylation of the heterochromatin enforcer KAP1/TRIM28 even in the absence of EBV genomes or other EBV proteins. Phosphorylation of KAP1 renders it unable to restrain ZEBRA, thereby further derepressing and sustaining its expression to culminate in virus production. This partnership with a host kinase and a transcriptional corepressor enables retrograde regulation by vPK of ZEBRA, an observation that is counter to the unidirectional regulation of gene expression reminiscent of most DNA viruses.IMPORTANCE Herpesviruses infect nearly all humans and persist quiescently for the life of the host. These viruses intermittently activate into the lytic phase to produce infectious virus, thereby causing disease. To ensure that lytic activation is not prematurely terminated, expression of the virally encoded lytic switch protein needs to be sustained. In studying Epstein-Barr virus, one of the most prevalent human herpesviruses that also causes cancer, we have discovered that a viral kinase activated by the viral lytic switch protein partners with a cellular kinase to deactivate a silencer of the lytic switch protein, thereby providing a positive feedback loop to ensure successful completion of the viral productive phase. Our findings highlight key nodes of interaction between the host and virus that could be exploited to treat lytic phase-associated diseases by terminating the lytic phase or kill cancer cells harboring herpesviruses by accelerating the completion of the lytic cascade.
Collapse
|
11
|
Abstract
Infections by DNA viruses including, Epstein–Barr virus (EBV), typically induce cellular DNA damage responses (DDR), in particular double-stranded break signaling. To avoid apoptosis associated with constitutive DDR signaling, downstream steps of this pathway must be inactivated. EBV has developed multiple ways of disabling the DDR using several different viral proteins expressed at various stages of EBV infection. Here the interplay between EBV and host DDRs is discussed at each stage of EBV infection, along with the EBV proteins and miRNAs that are known to interfere with DDR signaling. The newly discovered APOBEC editing of EBV DNA and protection from this mutation is also discussed.
Collapse
Affiliation(s)
- Lori Frappier
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| |
Collapse
|
12
|
A Screen for Epstein-Barr Virus Proteins That Inhibit the DNA Damage Response Reveals a Novel Histone Binding Protein. J Virol 2018; 92:JVI.00262-18. [PMID: 29743367 DOI: 10.1128/jvi.00262-18] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 05/02/2018] [Indexed: 12/17/2022] Open
Abstract
To replicate and persist in human cells, linear double-stranded DNA (dsDNA) viruses, such as Epstein-Barr virus (EBV), must overcome the host DNA damage response (DDR) that is triggered by the viral genomes. Since this response is necessary to maintain cellular genome integrity, its inhibition by EBV is likely an important factor in the development of cancers associated with EBV infection, including gastric carcinoma. Here we present the first extensive screen of EBV proteins that inhibit dsDNA break signaling. We identify the BKRF4 tegument protein as a DDR inhibitor that interferes with histone ubiquitylation at dsDNA breaks and recruitment of the RNF168 histone ubiquitin ligase. We further show that BKRF4 binds directly to histones through an acidic domain that targets BKRF4 to cellular chromatin and is sufficient to inhibit dsDNA break signaling. BKRF4 transcripts were detected in EBV-positive gastric carcinoma cells (AGS-EBV), and these increased in lytic infection. Silencing of BKRF4 in both latent and lytic AGS-EBV cells (but not in EBV-negative AGS cells) resulted in increased dsDNA break signaling, confirming a role for BKRF4 in DDR inhibition in the context of EBV infection and suggesting that BKRF4 is expressed in latent cells. BKRF4 was also found to be consistently expressed in EBV-positive gastric tumors in the absence of a full lytic infection. The results suggest that BKRF4 plays a role in inhibiting the cellular DDR in latent and lytic EBV infection and that the resulting accumulation of DNA damage might contribute to development of gastric carcinoma.IMPORTANCE Epstein-Barr virus (EBV) infects most people worldwide and is causatively associated with several types of cancer, including ∼10% of gastric carcinomas. EBV encodes ∼80 proteins, many of which are believed to manipulate cellular regulatory pathways but are poorly characterized. The DNA damage response (DDR) is one such pathway that is critical for maintaining genome integrity and preventing cancer-associated mutations. In this study, a screen for EBV proteins that inhibit the DDR identified BKRF4 as a DDR inhibitor that binds histones and blocks their ubiquitylation at the DNA damage sites. We also present evidence that BKRF4 is expressed in both latent and lytic forms of EBV infection, where it downregulates the DDR, as well as in EBV-positive gastric tumors. The results suggest that BKRF4 could contribute to the development of gastric carcinoma through its ability to inhibit the DDR.
Collapse
|
13
|
Tong Z, Rajeev G, Guo K, Ivask A, McCormick S, Lombi E, Priest C, Voelcker NH. Microfluidic Cell Microarray Platform for High Throughput Analysis of Particle–Cell Interactions. Anal Chem 2018; 90:4338-4347. [DOI: 10.1021/acs.analchem.7b03079] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Ziqiu Tong
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
- Future Industries Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | - Gayathri Rajeev
- Future Industries Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | - Keying Guo
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
- Future Industries Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | - Angela Ivask
- Future Industries Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | - Scott McCormick
- Future Industries Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | - Enzo Lombi
- Future Industries Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | - Craig Priest
- Future Industries Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia
| | - Nicolas H. Voelcker
- Drug Delivery, Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
- Future Industries Institute, University of South Australia, Mawson Lakes, South Australia 5095, Australia
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Clayton, Victoria 3168, Australia
- Melbourne Centre for Nanofabrication, Victorian Node of the Australian National Fabrication Facility, Clayton, Victoria 3168, Australia
- Monash Institute of Medical Engineering, Monash University, Clayton, Victoria 3168, Australia
| |
Collapse
|
14
|
Activation of ATR-Chk1 pathway facilitates EBV-mediated transformation of primary tonsillar B-cells. Oncotarget 2018; 8:6461-6474. [PMID: 28031537 PMCID: PMC5351645 DOI: 10.18632/oncotarget.14120] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 12/18/2016] [Indexed: 01/05/2023] Open
Abstract
Primary infection of the immunocompromised host with the oncovirus Epstein-Barr virus (EBV) that targets mainly B-cells is associated with an increased risk for EBV-associated tumors. The early events subsequent to primary infection with potential for B-cell transformation are poorly studied. Here, we modeled in vitro the primary infection by using B-cells isolated from tonsils, the portal of entry of EBV, since species specificity of EBV hampers modeling in experimental animals. Increasing evidence indicates that the host DNA damage response (DDR) can influence and be influenced by EBV infection. Thus, we inoculated tonsillar B-cells (TBCs) with EBV-B95.8 and investigated cell proliferation and the DDR during the first 96 hours thereafter. We identified for the first time that EBV infection of TBCs induces a period of hyperproliferation 48-96 hours post infection characterized by the activation of ataxia telangiectasia and Rad3-releated (ATR) and checkpoint kinase-1 (Chk1). Whereas inhibition of Chk1 did not affect B-cell transformation, the specific inhibition of ATR robustly decreased the transformation efficiency of EBV. Our results suggest that activation of ATR is key for EBV-induced B-cell transformation. Thus, targeting the interaction between ATR/Chk1 and EBV could offer new options for the treatment of EBV-associated malignancies.
Collapse
|
15
|
Hau PM, Tsao SW. Epstein-Barr Virus Hijacks DNA Damage Response Transducers to Orchestrate Its Life Cycle. Viruses 2017; 9:v9110341. [PMID: 29144413 PMCID: PMC5707548 DOI: 10.3390/v9110341] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 10/30/2017] [Accepted: 11/08/2017] [Indexed: 12/12/2022] Open
Abstract
The Epstein–Barr virus (EBV) is a ubiquitous virus that infects most of the human population. EBV infection is associated with multiple human cancers, including Burkitt’s lymphoma, Hodgkin’s lymphoma, a subset of gastric carcinomas, and almost all undifferentiated non-keratinizing nasopharyngeal carcinoma. Intensive research has shown that EBV triggers a DNA damage response (DDR) during primary infection and lytic reactivation. The EBV-encoded viral proteins have been implicated in deregulating the DDR signaling pathways. The consequences of DDR inactivation lead to genomic instability and promote cellular transformation. This review summarizes the current understanding of the relationship between EBV infection and the DDR transducers, including ATM (ataxia telangiectasia mutated), ATR (ATM and Rad3-related), and DNA-PK (DNA-dependent protein kinase), and discusses how EBV manipulates the DDR signaling pathways to complete the replication process of viral DNA during lytic reactivation.
Collapse
Affiliation(s)
- Pok Man Hau
- Department of Anatomical and Cellular Pathology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China.
| | - Sai Wah Tsao
- School of Biomedical Science, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
| |
Collapse
|
16
|
The regulatory role of protein phosphorylation in human gammaherpesvirus associated cancers. Virol Sin 2017; 32:357-368. [PMID: 29116588 PMCID: PMC6704201 DOI: 10.1007/s12250-017-4081-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 10/23/2017] [Indexed: 12/12/2022] Open
Abstract
Activation of specific sets of protein kinases by intracellular signal molecules
has become more and more apparent in the past decade. Phosphorylation, one of key
posttranslational modification events, is activated by kinase or regulatory protein
and is vital for controlling many physiological functions of eukaryotic cells such
as cell proliferation, differentiation, malignant transformation, and signal
transduction mediated by external stimuli. Moreovers, the reversible modification of
phosphorylation and dephosphorylation can result in different features of the target
substrate molecules including DNA binding, protein-protein interaction, subcellular
location and enzymatic activity, and is often hijacked by viral infection.
Epstein-Barr virus (EBV) and Kaposi’s sarcomaassociated herpesvirus (KSHV), two
human oncogenic gamma-herpesviruses, are shown to tightly associate with many
malignancies. In this review, we summarize the recent progresses on understanding of
molecular properties and regulatory modes of cellular and viral proteins
phosphorylation influenced by these two tumor viruses, and highlight the potential
therapeutic targets and strategies against their related cancers. ![]()
Collapse
|
17
|
Sui X, Zhang C, Zhou J, Cao S, Xu C, Tang F, Zhi X, Chen B, Wang S, Yin L. Resveratrol inhibits Extranodal NK/T cell lymphoma through activation of DNA damage response pathway. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2017; 36:133. [PMID: 28950914 PMCID: PMC5615630 DOI: 10.1186/s13046-017-0601-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Accepted: 09/13/2017] [Indexed: 02/07/2023]
Abstract
Background Extranodal NK/T cell lymphoma (NKTCL) is a highly aggressive non-Hodgkin lymphoma with poor prognosis. Resveratrol (RSV, 3,5,4′-trihydroxystilbene), a natural nontoxic phenolic compound found in the skin of grapes and some other spermatophytes, performs multiple bioactivities, such as antioxidant activity, anti-aging activity, reduction of cardiovascular disease risk and anticarcinogenic effect. Here we report the anti-tumor effect of RSV in NKTCL cell lines SNT-8, SNK-10 and SNT-16. Results RSV inhibited NKTCL cell proliferation in a dose- and time-dependent manner and arrested cell cycle at S phase. It induced NKTCL cells apoptosis through mitochondrial pathway, shown as down-regulation of MCl-1 and survivin, up-regulation of Bax and Bad, and activation of caspase-9 and caspase-3. In addition, we found that RSV suppressed the phosphorylation level of AKT and Stat3, and activated DNA damage response (DDR) pathway directly or through up-regulation of Zta of Epstein-Barr virus (EBV). Furthermore, using KU55933 as the inhibitor of pATM, we verified that DDR played an important role in RSV inducing NKTCL apoptosis. RSV also showed synergistic effect on activating DDR pathway in combination with etoposide or ionizing radiation, which resulted in cell proliferation inhibition and apoptosis. Conclusions Our results provide in vitro evidence that RSV produces anti-tumor effect by activating DDR pathway in an ATM/Chk2/p53 dependent manner. So we suggest that RSV may be worthy for further study as an anti-tumor drug for NKTCL treatment. Electronic supplementary material The online version of this article (10.1186/s13046-017-0601-6) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Xianxian Sui
- Department of Physiology & Pathophysiology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Canjing Zhang
- The Institution of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, China
| | - Jianan Zhou
- Department of Hematology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Shengxuan Cao
- Shanghai Medical College, Fudan University, Shanghai, China
| | - Chen Xu
- Department of Pathology, Zhongshan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Feng Tang
- Department of Pathology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Xiuling Zhi
- Laboratory of Medical Molecular Biology, Experimental Teaching Center, School of Basic Medical Sciences, Fudan University, 131 Dongan Rd, Shanghai, 200032, China
| | - Bobin Chen
- Department of Hematology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Songmei Wang
- Laboratory of Medical Molecular Biology, Experimental Teaching Center, School of Basic Medical Sciences, Fudan University, 131 Dongan Rd, Shanghai, 200032, China.
| | - Lianhua Yin
- Department of Physiology & Pathophysiology, School of Basic Medical Sciences, Fudan University, Shanghai, China. .,Laboratory of Medical Molecular Biology, Experimental Teaching Center, School of Basic Medical Sciences, Fudan University, 131 Dongan Rd, Shanghai, 200032, China.
| |
Collapse
|
18
|
Li X, Burton EM, Bhaduri-McIntosh S. Chloroquine triggers Epstein-Barr virus replication through phosphorylation of KAP1/TRIM28 in Burkitt lymphoma cells. PLoS Pathog 2017; 13:e1006249. [PMID: 28249048 PMCID: PMC5348047 DOI: 10.1371/journal.ppat.1006249] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Revised: 03/13/2017] [Accepted: 02/17/2017] [Indexed: 01/09/2023] Open
Abstract
Trials to reintroduce chloroquine into regions of Africa where P. falciparum has regained susceptibility to chloroquine are underway. However, there are long-standing concerns about whether chloroquine increases lytic-replication of Epstein-Barr virus (EBV), thereby contributing to the development of endemic Burkitt lymphoma. We report that chloroquine indeed drives EBV replication by linking the DNA repair machinery to chromatin remodeling-mediated transcriptional repression. Specifically, chloroquine utilizes ataxia telangiectasia mutated (ATM) to phosphorylate the universal transcriptional corepressor Krüppel-associated Box-associated protein 1/tripartite motif-containing protein 28 (KAP1/TRIM28) at serine 824 -a mechanism that typically facilitates repair of double-strand breaks in heterochromatin, to instead activate EBV. Notably, activation of ATM occurs in the absence of detectable DNA damage. These findings i) clarify chloroquine's effect on EBV replication, ii) should energize field investigations into the connection between chloroquine and endemic Burkitt lymphoma and iii) provide a unique context in which ATM modifies KAP1 to regulate persistence of a herpesvirus in humans.
Collapse
Affiliation(s)
- Xiaofan Li
- Division of Infectious Diseases, Department of Pediatrics, Stony Brook University School of Medicine, Stony Brook, NY, United States of America
| | - Eric M. Burton
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY, United States of America
| | - Sumita Bhaduri-McIntosh
- Division of Infectious Diseases, Department of Pediatrics, Stony Brook University School of Medicine, Stony Brook, NY, United States of America
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY, United States of America
- * E-mail:
| |
Collapse
|
19
|
Huang L, Yang M, Yuan Y, Li X, Kuang E. Niclosamide inhibits lytic replication of Epstein-Barr virus by disrupting mTOR activation. Antiviral Res 2016; 138:68-78. [PMID: 27939840 DOI: 10.1016/j.antiviral.2016.12.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Revised: 11/30/2016] [Accepted: 12/05/2016] [Indexed: 12/31/2022]
Abstract
Infection with the oncogenic γ-herpesviruses Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) cause several severe malignancies in humans. Inhibition of the lytic replication of EBV and KSHV eliminates the reservoir of persistent infection and transmission, consequently preventing the occurrence of diseases from the sources of infection. Antiviral drugs are limited in controlling these viral infectious diseases. Here, we demonstrate that niclosamide, an old anthelmintic drug, inhibits mTOR activation during EBV lytic replication. Consequently, niclosamide effectively suppresses EBV lytic gene expression, viral DNA lytic replication and virion production in EBV-infected lymphoma cells and epithelial cells. Niclosamide exhibits cytotoxicity toward lymphoma cells and induces irreversible cell cycle arrest in lytically EBV-infected cells. The ectopic overexpression of mTOR reverses the inhibition of niclosamide in EBV lytic replication. Similarly, niclosamide inhibits KSHV lytic replication. Thus, we conclude that niclosamide is a promising candidate for chemotherapy against the acute occurrence and transmission of infectious diseases of oncogenic γ-herpesviruses.
Collapse
Affiliation(s)
- Lu Huang
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Mengtian Yang
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Yan Yuan
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
| | - Xiaojuan Li
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China.
| | - Ersheng Kuang
- Institute of Human Virology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China; Key Laboratory of Tropical Disease Control (Sun Yat-Sen University), Ministry of Education, Guangzhou, China.
| |
Collapse
|