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Pietruszewska M, Biesiada G, Czepiel J, Birczyńska-Zych M, Moskal P, Garlicki A, Wesełucha-Birczyńska A. Raman spectroscopy of lymphocytes from patients with the Epstein-Barr virus infection. Sci Rep 2024; 14:6417. [PMID: 38494496 PMCID: PMC10944829 DOI: 10.1038/s41598-024-56864-y] [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: 10/23/2023] [Accepted: 03/12/2024] [Indexed: 03/19/2024] Open
Abstract
In this study, Raman spectroscopy is applied to trace lymphocytes activation following contact with the Epstein-Barr virus (EBV) of the herpesvirus family. The biomarker of cell activation is found to be the 520 cm-1 band, indicating formation of immunoglobulins. The blood samples are obtained from patients diagnosed with infectious mononucleosis and treated at the University Hospital in Kraków. The lymphocytes' Raman spectra are collected using a mapping technique, exciting samples with a 514.5 nm line of Ar + laser. Measurements are performed on the 1st, 4th, 6th, 12th and 30th day of hospitalization, until the patient has recovered. The highest intensity of the immunoglobulin marker is observed on the 4th day of hospitalization, while the results of the blood count of patients show the greatest increase in the number of lymphocytes at the beginning of hospitalization. No activated lymphocytes were observed in the blood of healthy volunteers. Some information is provided by the evaluation of B-cell activation by estimating the activated areas in the cells, which are determined by the presence of the Ig marker. The 900 cm-1 band and band around 1450 cm-1 are also analyzed as markers of the presence of the latent membrane protein, LMP2A (and 2B), of the EBV viral protein. The anomalous degree of depolarization observed in B-cells in the course of EBV infection appears to be due to the influence of a virus protein, disrupting BCR signal transduction.
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Affiliation(s)
| | - Grażyna Biesiada
- Department of Infectious Diseases, Jagiellonian University, Medical College, Jakubowskiego 2, 30-688, Kraków, Poland
- The University Hospital in Kraków, Jakubowskiego 2, 30-688, Kraków, Poland
| | - Jacek Czepiel
- Department of Infectious Diseases, Jagiellonian University, Medical College, Jakubowskiego 2, 30-688, Kraków, Poland
- The University Hospital in Kraków, Jakubowskiego 2, 30-688, Kraków, Poland
| | - Malwina Birczyńska-Zych
- Department of Infectious Diseases, Jagiellonian University, Medical College, Jakubowskiego 2, 30-688, Kraków, Poland
- The University Hospital in Kraków, Jakubowskiego 2, 30-688, Kraków, Poland
| | - Paulina Moskal
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland
| | - Aleksander Garlicki
- Department of Infectious Diseases, Jagiellonian University, Medical College, Jakubowskiego 2, 30-688, Kraków, Poland
- The University Hospital in Kraków, Jakubowskiego 2, 30-688, Kraków, Poland
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The lytic phase of Epstein-Barr virus plays an important role in tumorigenesis. Virus Genes 2023; 59:1-12. [PMID: 36242711 DOI: 10.1007/s11262-022-01940-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 10/02/2022] [Indexed: 01/13/2023]
Abstract
Epstein-Barr virus (EBV) is a recognized oncogenic virus that is related to the occurrence of lymphoma, nasopharyngeal carcinoma (NPC), and approximately 10% of gastric cancer (GC). EBV is a herpesvirus, and like other herpesviruses, EBV has a biphasic infection mode made up of latent and lytic infections. It has been established that latent infection promotes tumorigenesis in previous research, but in recent years, there has been new evidence that suggests that the lytic infection mode could also promote tumorigenesis. In this review, we mainly discuss the contribution of the EBV lytic phase to tumorigenesis, and graphically illustrate their relationship in detail. In addition, we described the relationship between the lytic cycle of EBV and autophagy. Finally, we also preliminarily explored the influence of the tumorigenesis effect of the EBV lytic phase on the future treatment of EBV-associated tumors.
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3
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Chua HH, Kameyama T, Mayeda A, Yeh TH. Epstein-Barr Virus Enhances Cancer-Specific Aberrant Splicing of TSG101 Pre-mRNA. Int J Mol Sci 2022; 23:ijms23052516. [PMID: 35269659 PMCID: PMC8910672 DOI: 10.3390/ijms23052516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 02/21/2022] [Accepted: 02/21/2022] [Indexed: 11/16/2022] Open
Abstract
Tumor viruses gain control of cellular functions when they infect and transform host cells. Alternative splicing is one of the cellular processes exploited by tumor viruses to benefit viral replication and support oncogenesis. Epstein-Barr virus (EBV) participates in a number of cancers, as reported mostly in nasopharyngeal carcinoma (NPC) and Burkitt lymphoma (BL). Using RT-nested-PCR and Northern blot analysis in NPC and BL cells, here we demonstrate that EBV promotes specific alternative splicing of TSG101 pre-mRNA, which generates the TSG101∆154-1054 variant though the agency of its viral proteins, such as EBNA-1, Zta and Rta. The level of TSG101∆154-1054 is particularly enhanced upon EBV entry into the lytic cycle, increasing protein stability of TSG101 and causing the cumulative synthesis of EBV late lytic proteins, such as VCA and gp350/220. TSG101∆154-1054-mediated production of VCA and gp350/220 is blocked by the overexpression of a translational mutant of TSG101∆154-1054 or by the depletion of full-length TSG101, which is consistent with the known role of the TSG101∆154-1054 protein in stabilizing the TSG101 protein. NPC patients whose tumor tissues express TSG101∆154-1054 have high serum levels of anti-VCA antibodies and high levels of viral DNA in their tumors. Our findings highlight the functional importance of TSG101∆154-1054 in allowing full completion of the EBV lytic cycle to produce viral particles. We propose that targeting EBV-induced TSG101 alternative splicing has broad potential as a therapeutic to treat EBV-associated malignancies.
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Affiliation(s)
- Huey-Huey Chua
- Department of Pediatrics, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei 100226, Taiwan;
| | - Toshiki Kameyama
- Department of Physiology, School of Medicine, Fujita Health University, Toyoake 470-1192, Aichi, Japan;
| | - Akila Mayeda
- Division of Gene Expression Mechanism, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake 470-1192, Aichi, Japan
- Correspondence: (A.M.); (T.-H.Y.)
| | - Te-Huei Yeh
- Department of Otolaryngology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei 100225, Taiwan
- Correspondence: (A.M.); (T.-H.Y.)
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Malat P, Ekalaksananan T, Heawchaiyaphum C, Suebsasana S, Roytrakul S, Yingchutrakul Y, Pientong C. Andrographolide Inhibits Lytic Reactivation of Epstein-Barr Virus by Modulating Transcription Factors in Gastric Cancer. Microorganisms 2021; 9:microorganisms9122561. [PMID: 34946164 PMCID: PMC8708910 DOI: 10.3390/microorganisms9122561] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 12/07/2021] [Accepted: 12/08/2021] [Indexed: 12/24/2022] Open
Abstract
Andrographolide is the principal bioactive chemical constituent of Andrographis paniculata and exhibits activity against several viruses, including Epstein–Barr virus (EBV). However, the particular mechanism by which andrographolide exerts an anti-EBV effect in EBV-associated gastric cancer (EBVaGC) cells remains unclear. We investigated the molecular mechanism by which andrographolide inhibits lytic reactivation of EBV in EBVaGC cells (AGS-EBV cell line) using proteomics and bioinformatics approaches. An andrographolide treatment altered EBV protein-expression patterns in AGS-EBV cells by suppressing the expression of EBV lytic protein. Interestingly cellular transcription factors (TFs), activators for EBV lytic reactivation, such as MEF2D and SP1, were significantly abolished in AGS-EBV cells treated with andrographolide and sodium butyrate (NaB) compared with NaB-treated cells. In contrast, the suppressors of EBV lytic reactivation, such as EZH2 and HDAC6, were significantly up-regulated in cells treated with both andrographolide and NaB compared with NaB treatment alone. In addition, bioinformatics predicted that HDAC6 could interact directly with MEF2D and SP1. Furthermore, andrographolide significantly induced cell cytotoxicity and apoptosis of AGS-EBV cells by induction of apoptosis-related protein expression. Our results suggest that andrographolide inhibits EBV lytic reactivation by inhibition of host TFs, partially through the interaction of HDAC6 with TFs, and induces apoptosis of EBVaGC cells.
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Affiliation(s)
- Praphatson Malat
- Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand; (P.M.); (T.E.); (C.H.)
- HPV & EBV and Carcinogenesis Research Group, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Tipaya Ekalaksananan
- Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand; (P.M.); (T.E.); (C.H.)
- HPV & EBV and Carcinogenesis Research Group, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Chukkris Heawchaiyaphum
- Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand; (P.M.); (T.E.); (C.H.)
- HPV & EBV and Carcinogenesis Research Group, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Supawadee Suebsasana
- Department of Pharmaceutical Sciences, Faculty of Pharmacy, Thammasat University, Bangkok 10200, Thailand;
| | - Sittiruk Roytrakul
- Genome Technology Research Unit, Proteomics Research Laboratory, National Center for Genetic Engineering and Biotechnology (BIOTEC), Pathum Thani 12120, Thailand; (S.R.); (Y.Y.)
| | - Yodying Yingchutrakul
- Genome Technology Research Unit, Proteomics Research Laboratory, National Center for Genetic Engineering and Biotechnology (BIOTEC), Pathum Thani 12120, Thailand; (S.R.); (Y.Y.)
| | - Chamsai Pientong
- Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand; (P.M.); (T.E.); (C.H.)
- HPV & EBV and Carcinogenesis Research Group, Khon Kaen University, Khon Kaen 40002, Thailand
- Correspondence:
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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.
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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
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6
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Ubiquitin Modification of the Epstein-Barr Virus Immediate Early Transactivator Zta. J Virol 2020; 94:JVI.01298-20. [PMID: 32847852 DOI: 10.1128/jvi.01298-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 08/19/2020] [Indexed: 12/17/2022] Open
Abstract
The Epstein-Barr virus (EBV) immediate early transactivator Zta plays a key role in regulating the transition from latency to the lytic replication stages of EBV infection. Regulation of Zta is known to be controlled through a number of transcriptional and posttranscriptional events. Here, we show that Zta is targeted for ubiquitin modification and that this can occur in EBV-negative and in EBV-infected cells. Genetic studies show critical roles for both an amino-terminal region of Zta and the basic DNA binding domain of Zta in regulating Zta ubiquitination. Pulse-chase experiments demonstrate that the bulk population of Zta is relatively stable but that at least a subset of ubiquitinated Zta molecules are targeted for degradation in the cell. Mutation of four out of a total of nine lysine residues in Zta largely abrogates its ubiquitination, indicating that these are primary ubiquitination target sites. A Zta mutant carrying mutations at these four lysine residues (lysine 12, lysine 188, lysine 207, and lysine 219) cannot induce latently infected cells to produce and/or release infectious virions. Nevertheless, this mutant can induce early gene expression, suggesting a possible defect at the level of viral replication or later in the lytic cascade. As far as we know, this is the first study that has investigated the targeting of Zta by ubiquitination or its role in Zta function.IMPORTANCE Epstein-Barr virus (EBV) is a ubiquitous human pathogen and associated with various human diseases. EBV undergoes latency and lytic replication stages in its life cycle. The transition into the lytic replication stage, at which virus is produced, is mainly regulated by the viral gene product, Zta. Therefore, the regulation of Zta function becomes a central issue regarding viral biology and pathogenesis. Known modifications of Zta include phosphorylation and sumoylation. Here, we report the role of ubiquitination in regulating Zta function. We found that Zta is subjected to ubiquitination in both EBV-infected and EBV-negative cells. The ubiquitin modification targets 4 lysine residues on Zta, leading to both mono- and polyubiquitination of Zta. Ubiquitination of Zta affects the protein's stability and likely contributes to the progression of viral lytic replication. The function and fate of Zta may be determined by the specific lysine residue being modified.
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7
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Stolz ML, McCormick C. The bZIP Proteins of Oncogenic Viruses. Viruses 2020; 12:v12070757. [PMID: 32674309 PMCID: PMC7412551 DOI: 10.3390/v12070757] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 07/08/2020] [Accepted: 07/13/2020] [Indexed: 12/20/2022] Open
Abstract
Basic leucine zipper (bZIP) transcription factors (TFs) govern diverse cellular processes and cell fate decisions. The hallmark of the leucine zipper domain is the heptad repeat, with leucine residues at every seventh position in the domain. These leucine residues enable homo- and heterodimerization between ZIP domain α-helices, generating coiled-coil structures that stabilize interactions between adjacent DNA-binding domains and target DNA substrates. Several cancer-causing viruses encode viral bZIP TFs, including human T-cell leukemia virus (HTLV), hepatitis C virus (HCV) and the herpesviruses Marek’s disease virus (MDV), Epstein–Barr virus (EBV) and Kaposi’s sarcoma-associated herpesvirus (KSHV). Here, we provide a comprehensive review of these viral bZIP TFs and their impact on viral replication, host cell responses and cell fate.
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Regulation of EBV LMP1-triggered EphA4 downregulation in EBV-associated B lymphoma and its impact on patients' survival. Blood 2016; 128:1578-89. [PMID: 27338098 DOI: 10.1182/blood-2016-02-702530] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 06/15/2016] [Indexed: 12/21/2022] Open
Abstract
Epstein-Barr virus (EBV), an oncogenic human virus, is associated with several lymphoproliferative disorders, including Burkitt lymphoma, Hodgkin disease, diffuse large B-cell lymphoma (DLBCL), and posttransplant lymphoproliferative disorder (PTLD). In vitro, EBV transforms primary B cells into lymphoblastoid cell lines (LCLs). Recently, several studies have shown that receptor tyrosine kinases (RTKs) play important roles in EBV-associated neoplasia. However, details of the involvement of RTKs in EBV-regulated B-cell neoplasia and malignancies remain largely unclear. Here, we found that erythropoietin-producing hepatocellular receptor A4 (EphA4), which belongs to the largest RTK Eph family, was downregulated in primary B cells post-EBV infection at the transcriptional and translational levels. Overexpression and knockdown experiments confirmed that EBV-encoded latent membrane protein 1 (LMP1) was responsible for this EphA4 suppression. Mechanistically, LMP1 triggered the extracellular signal-regulated kinase (ERK) pathway and promoted Sp1 to suppress EphA4 promoter activity. Functionally, overexpression of EphA4 prevented LCLs from proliferation. Pathologically, the expression of EphA4 was detected in EBV(-) tonsils but not in EBV(+) PTLD. In addition, an inverse correlation of EphA4 expression and EBV presence was verified by immunochemical staining of EBV(+) and EBV(-) DLBCL, suggesting EBV infection was associated with reduced EphA4 expression. Analysis of a public data set showed that lower EphA4 expression was correlated with a poor survival rate of DLBCL patients. Our findings provide a novel mechanism by which EphA4 can be regulated by an oncogenic LMP1 protein and explore its possible function in B cells. The results provide new insights into the role of EphA4 in EBV(+) PTLD and DLBCL.
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Wang YP, Lin CF, Tsai SC, Tsai CH, Yeh TH. Upregulation of Caveolin-1 correlate with Akt expression and poor prognosis in NPC patients. Laryngoscope 2015; 125:E231-8. [DOI: 10.1002/lary.25297] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Revised: 02/17/2015] [Accepted: 03/09/2015] [Indexed: 11/11/2022]
Affiliation(s)
- Ying-Piao Wang
- Department of Otolaryngology; Mackay Memorial Hospital; Zhongzheng Rd Taipei Taiwan
- Department of Audiology and Speech Language Pathology and School of Medicine; Mackay Medical College; Zhongzheng Rd Taipei Taiwan
- Graduate Institute of Microbiology, College of Medicine National Taiwan University; Taipei Taiwan
| | - Chih-Feng Lin
- Department of Otolaryngology; National Taiwan University Hospital
| | - Shu-Chun Tsai
- Department of Otolaryngology; National Taiwan University Hospital
- Graduate Institute of Microbiology, College of Medicine National Taiwan University; Taipei Taiwan
| | - Ching-Hwa Tsai
- Department of Otolaryngology; National Taiwan University Hospital
| | - Te-Huei Yeh
- Department of Otolaryngology; National Taiwan University Hospital
- Graduate Institute of Microbiology, College of Medicine National Taiwan University; Taipei Taiwan
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10
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Lan YY, Yeh TH, Lin WH, Wu SY, Lai HC, Chang FH, Takada K, Chang Y. Epstein-Barr virus Zta upregulates matrix metalloproteinases 3 and 9 that synergistically promote cell invasion in vitro. PLoS One 2013; 8:e56121. [PMID: 23409137 PMCID: PMC3567054 DOI: 10.1371/journal.pone.0056121] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Accepted: 01/04/2013] [Indexed: 02/03/2023] Open
Abstract
Zta is a lytic transactivator of Epstein-Barr virus (EBV) and has been shown to promote migration and invasion of epithelial cells. Although previous studies indicate that Zta induces expression of matrix metalloproteinase (MMP) 9 and MMP1, direct evidence linking the MMPs to Zta-induced cell migration and invasion is still lacking. Here we performed a series of in vitro studies to re-examine the expression profile and biologic functions of Zta-induced MMPs in epithelial cells derived from nasopharyngeal carcinoma. We found that, in addition to MMP9, MMP3 was a new target gene upregulated by Zta. Ectopic Zta expression in EBV-negative cells increased both mRNA and protein production of MMP3. Endogenous Zta also contributed to induction of MMP3 expression, migration and invasion of EBV-infected cells. Zta activated the MMP3 promoter through three AP-1 elements, and its DNA-binding domain was required for the promoter binding and MMP3 induction. We further tested the effects of MMP3 and MMP9 on cell motility and invasiveness in vitro. Zta-promoted cell migration required MMP3 but not MMP9. On the other hand, both MMP3 and MMP9 were essential for Zta-induced cell invasion, and co-expression of the two MMPs synergistically increased cell invasiveness. Therefore, this study provides integrated evidence demonstrating that, at least in the in vitro cell models, Zta drives cell migration and invasion through MMPs.
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Affiliation(s)
- Yu-Yan Lan
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Tainan, Taiwan
- Graduate Institute of Basic Medical Sciences, Medical College and Hospital, National Cheng Kung University, Tainan, Taiwan
| | - Tzu-Hao Yeh
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Tainan, Taiwan
- Department of Microbiology and Immunology, Medical College and Hospital, National Cheng Kung University, Tainan, Taiwan
| | - Wei-Hung Lin
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Tainan, Taiwan
- Department of Microbiology and Immunology, Medical College and Hospital, National Cheng Kung University, Tainan, Taiwan
| | - Shih-Yi Wu
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Tainan, Taiwan
| | - Hsiao-Ching Lai
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Tainan, Taiwan
- Graduate Institute of Basic Medical Sciences, Medical College and Hospital, National Cheng Kung University, Tainan, Taiwan
| | - Fang-Hsin Chang
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Tainan, Taiwan
- Department of Microbiology and Immunology, Medical College and Hospital, National Cheng Kung University, Tainan, Taiwan
| | - Kenzo Takada
- Department of Tumor Virology, Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan
| | - Yao Chang
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Tainan, Taiwan
- Graduate Institute of Basic Medical Sciences, Medical College and Hospital, National Cheng Kung University, Tainan, Taiwan
- Department of Microbiology and Immunology, Medical College and Hospital, National Cheng Kung University, Tainan, Taiwan
- * E-mail:
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11
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Epstein-Barr virus BGLF4 kinase downregulates NF-κB transactivation through phosphorylation of coactivator UXT. J Virol 2012; 86:12176-86. [PMID: 22933289 DOI: 10.1128/jvi.01918-12] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Epstein-Barr virus (EBV) BGLF4 is a member of the conserved herpesvirus kinases that regulate multiple cellular and viral substrates and play an important role in the viral lytic cycles. BGLF4 has been found to phosphorylate several cellular and viral transcription factors, modulate their activities, and regulate downstream events. In this study, we identify an NF-κB coactivator, UXT, as a substrate of BGLF4. BGLF4 downregulates not only NF-κB transactivation in reporter assays in response to tumor necrosis factor alpha (TNF-α) and poly(I·C) stimulation, but also NF-κB-regulated cellular gene expression. Furthermore, BGLF4 attenuates NF-κB-mediated repression of the EBV lytic transactivators, Zta and Rta. In EBV-positive NA cells, knockdown of BGLF4 during lytic progression elevates NF-κB activity and downregulates the activity of the EBV oriLyt BHLF1 promoter, which is the first promoter activated upon lytic switch. We show that BGLF4 phosphorylates UXT at the Thr3 residue. This modification interferes with the interaction between UXT and NF-κB. The data also indicate that BGLF4 reduces the interaction between UXT and NF-κB and attenuates NF-κB enhanceosome activity. Upon infection with short hairpin RNA (shRNA) lentivirus to knock down UXT, a spontaneous lytic cycle was observed in NA cells, suggesting UXT is required for maintenance of EBV latency. Overexpression of wild-type, but not phosphorylation-deficient, UXT enhances the expression of lytic proteins both in control and UXT knockdown cells. Taking the data together, transcription involving UXT may also be important for EBV lytic protein expression, whereas BGLF4-mediated phosphorylation of UXT at Thr3 plays a critical role in promoting the lytic cycle.
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12
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Du ZM, Kou CW, Wang HY, Huang MY, Liao DZ, Hu CF, Chen J, Yan LX, Hu LF, Ernberg I, Zeng YX, Shao JY. Clinical significance of elevated spleen tyrosine kinase expression in nasopharyngeal carcinoma. Head Neck 2012; 34:1456-64. [PMID: 22287277 DOI: 10.1002/hed.21953] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/05/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Spleen tyrosine kinase (Syk) is a nonreceptor tyrosine kinase and often aberrantly expressed in human cancers. However, Syk expression pattern has not yet been investigated in nasopharyngeal carcinoma (NPC). METHODS Samples of 223 NPC tissues were immunohistochemically stained for Syk expression and survival analysis was then performed. Interaction and co-localization of Syk with Epstein-Barr virus encoded latent membrane protein 2A (LMP2A) was explored. RESULTS High expression of Syk was detected in 24% of NPC cases, and correlated significantly with T classification, local recurrence, a lower 5-year survival rate, and a lower 5-year disease-free survival (DFS) rate. Syk expression was a significant, independent prognosis predictor for patients with NPC. LMP2A induced Syk expression in NPC and LMP2A high expression correlated with Syk high expression in NPC clinical samples. CONCLUSION High expression of Syk, which results partly from LMP2A expression in NPC, is associated with tumor recurrence and poor prognosis of patients with NPC.
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Affiliation(s)
- Zi-Ming Du
- State Key Laboratory of Oncology in South China and Department of Pathology, Sun Yat-Sen University Cancer Center, Guangzhou 510060, People's Republic of China
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13
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Requirement for LMP1-induced RON receptor tyrosine kinase in Epstein-Barr virus-mediated B-cell proliferation. Blood 2011; 118:1340-9. [PMID: 21659546 DOI: 10.1182/blood-2011-02-335448] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
EBV, an oncogenic human herpesvirus, can transform primary B lymphocytes into immortalized lymphoblastoid cell lines (LCLs) through multiple regulatory mechanisms. However, the involvement of protein tyrosine kinases in the infinite proliferation of B cells is not clear. In this study, we performed kinase display assays to investigate this subject and identified a specific cellular target, Recepteur d'Origine Nantais (RON) tyrosine kinase, expressed in LCLs but not in primary B cells. Furthermore, we found that latent membrane protein 1 (LMP1), an important EBV oncogenic protein, enhanced RON expression through its C-terminal activation region-1 (CTAR1) by promoting NF-κB binding to the RON promoter. RON knockdown decreased the proliferation of LCLs, and transfection with RON compensated for the growth inhibition caused by knockdown of LMP1. Immunohistochemical analysis revealed a correlation between LMP1 and RON expression in biopsies from posttransplantation lymphoproliferative disorder (PTLD), suggesting that LMP1-induced RON expression not only is essential for the growth of LCLs but also may contribute to the pathogenesis of EBV-associated PTLD. Our study is the first to reveal the impact of RON on the proliferation of transformed B cells and to suggest that RON may be a novel therapeutic target for EBV-associated lymphoproliferative diseases.
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14
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Epstein-Barr virus Zta-induced immunomodulators from nasopharyngeal carcinoma cells upregulate interleukin-10 production from monocytes. J Virol 2011; 85:7333-42. [PMID: 21543473 DOI: 10.1128/jvi.00182-11] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
During lytic infection with Epstein-Barr virus (EBV), several viral lytic proteins function to evade immune recognition or to actively suppress immune cells. An EBV lytic transactivator, Zta, induces an immunosuppressive cytokine interleukin 10 (IL-10) in B cells, but whether it regulates IL-10 in the context of epithelial cells is unclear. In this study, we tested nasopharyngeal carcinoma (NPC) cell lines and found that Zta did not induce IL-10 in these epithelial cells. Interestingly, the conditioned medium of Zta-expressing NPC cells enhanced IL-10 production from monocytes. We further revealed that the IL-10-inducing effect involved at least two immunomodulators that were upregulated by Zta and secreted from NPC cells: granulocyte-macrophage colony-stimulating factor (GM-CSF) and prostaglandin E(2) (PGE(2)). Zta was recruited to and activated the GM-CSF promoter, thus upregulating GM-CSF expression. Zta also activated the promoter of cyclooxygenase-2 (COX-2), and Zta-induced COX-2 increased downstream PGE(2) production. Cotreatment with GM-CSF and PGE(2) synergistically induced IL-10 production from monocytes. The IL-10-inducing effect of the Zta-conditioned medium was reduced when GM-CSF or the COX-2/PGE(2) pathway was blocked. The conditioned medium of NPC cells with EBV lytic infection showed a similar increase of GM-CSF and PGE(2) levels as well as the IL-10-inducing effect on monocytes, and knockdown of Zta abolished all the effects. Therefore, through Zta-induced immunomodulators, EBV lytic infection in NPC cells can direct bystander monocytes to produce IL-10, which may be a novel way of EBV to promote local immunosuppression.
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Clyde K, Glaunsinger BA. Getting the message direct manipulation of host mRNA accumulation during gammaherpesvirus lytic infection. Adv Virus Res 2011; 78:1-42. [PMID: 21040830 DOI: 10.1016/b978-0-12-385032-4.00001-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The Gammaherpesvirinae subfamily of herpesviruses comprises lymphotropic viruses, including the oncogenic human pathogens Epstein-Barr virus and Kaposi's sarcoma-associated herpesvirus. During lytic infection, gammaherpesviruses manipulate host gene expression to optimize the cellular environment for viral replication and to evade the immune response. Additionally, although a lytically infected cell will itself be killed in the process of viral replication, lytic infection can contribute to pathogenesis by inducing the secretion of paracrine factors with functions in cell survival and proliferation, and angiogenesis. The mechanisms by which these viruses manipulate host gene expression are varied and target the accumulation of cellular mRNAs and their translation, signaling pathways, and protein stability. Here, we discuss how gammaherpesviral proteins directly influence host mRNA biogenesis and stability, either selectively or globally, in order to fine-tune the cellular environment to the advantage of the virus. Appreciation of the mechanisms by which these viruses interface with and adapt normal cellular processes continues to inform our understanding of gammaherpesviral biology and the regulation of mRNA accumulation and turnover in our own cells.
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Affiliation(s)
- Karen Clyde
- Department of Plant and Microbial Biology, University of California, Berkeley, USA
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16
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Chen YF, Tung CL, Chang Y, Hsiao WC, Su LJ, Sun HS. Analysis of global methylation using a Zta-expressing nasopharyngeal carcinoma cell line. Genomics 2011; 97:205-13. [PMID: 21195163 DOI: 10.1016/j.ygeno.2010.12.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2010] [Revised: 12/12/2010] [Accepted: 12/14/2010] [Indexed: 11/28/2022]
Abstract
EBV infects more than 90% of the human population and persists in most individuals as a latent infection where the viral genome is silenced by host-driven methylation. The lytic cycle is initiated when the viral protein Zta binds to methylated BRLF1 and BRRF1 promoters. Although studies reveal the role of Zta and methylation changes in the viral genome upon EBV infection to reactivation, whether Zta plays any role in alteration of methylation in the host genome remains unknown. Using an inducible model, we demonstrate that global DNA methylation, based on whole-genome 5-methylcytosine content, and regional DNA methylation in repetitive elements, imprinting genes and the X chromosome, remains unchanged in response to Zta expression. Expression of DNA methyltransferases was also unaffected by ectopically expressed Zta. Our data imply that alteration of host gene expression following EBV reactivation may reflect methylation-independent Zta-mediated gene activation and not epigenetic modification of the host genome.
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Affiliation(s)
- Ying-Fan Chen
- Institute of Basic Medicine, College of Medicine, National Chung Kung University, Tainan, Taiwan
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17
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Huang YT, Liu MY, Tsai CH, Yeh TH. Upregulation of interleukin-1 by Epstein-Barr virus latent membrane protein 1 and its possible role in nasopharyngeal carcinoma cell growth. Head Neck 2010; 32:869-76. [PMID: 19827118 DOI: 10.1002/hed.21270] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Nasopharyngeal carcinoma (NPC) is associated with Epstein-Barr virus (EBV) infection. We previously found that interleukin (IL)-1alpha and IL-1beta significantly increased in NPC tissues. This study investigated what EBV-encoded proteins were involved in such IL-1 production. METHODS AND RESULTS IL-1alpha and IL-1beta messenger ribonucleic acids (mRNAs) were detected in the EBV latent membrane protein 1 (LMP1) transfectant (LMP135) only by reverse transcriptase-polymerase chain reaction (RT-PCR). LMP1-mediated IL-1alpha and IL-1beta production could be enhanced by tumor necrosis factor alpha (TNF-alpha), determined by enzyme-linked immunosorbent assay (ELISA). Moreover, IL-1alpha and IL-1beta mRNAs and proteins were increased in a dose-dependent manner in epithelial cells transiently transfected by an LMP1 plasmid. Besides, immortalized human epidermal keratinocyte (RHEK-1) epithelial cells could be enhanced to proliferate by IL-1alpha and IL-1beta determined by water-soluble tetrazolium salt (WST-1) assay. CONCLUSIONS EBV LMP1 is capable of upregulating IL-1alpha and IL-1beta secretions from epithelial cells and positively modulated by TNF-alpha. This may consequently contribute to tumor growth in patients with NPC.
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Affiliation(s)
- Yu-Tzu Huang
- School of Medicine, Fu Jen Catholic University, Hsin-Chuang, Taipei Hsien, Taiwan, Republic of China
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18
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EBV Zta protein induces the expression of interleukin-13, promoting the proliferation of EBV-infected B cells and lymphoblastoid cell lines. Blood 2009; 114:109-18. [PMID: 19417211 DOI: 10.1182/blood-2008-12-193375] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Epstein-Barr virus (EBV) infection can modify the cytokine expression profiles of host cells and determine the fate of those cells. Of note, expression of interleukin-13 (IL-13) may be detected in EBV-associated Hodgkin lymphoma and the natural killer (NK) cells of chronic active EBV-infected patients, but its biologic role and regulatory mechanisms are not understood. Using cytokine antibody arrays, we found that IL-13 production is induced in B cells early during EBV infection. Furthermore, the EBV lytic protein, Zta (also known as the BZLF-1 product), which is a transcriptional activator, was found to induce IL-13 expression following transfection. Mechanistically, induction of IL-13 expression by Zta is mediated directly through its binding to the IL-13 promoter, via a consensus AP-1 binding site. Blockade of IL-13 by antibody neutralization showed that IL-13 is required at an early stage of EBV-induced proliferation and for long-term maintenance of the growth of EBV immortalized lymphoblastoid cell lines (LCLs). Thus, Zta-induced IL-13 production facilitates B-cell proliferation and may contribute to the pathogenesis of EBV-associated lymphoproliferative disorders, such as posttransplantation lymphoproliferative disease (PTLD) and Hodgkin lymphoma.
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19
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Chua HH, Yeh TH, Wang YP, Huang YT, Sheen TS, Lo YC, Chou YC, Tsai CH. Upregulation of discoidin domain receptor 2 in nasopharyngeal carcinoma. Head Neck 2008; 30:427-36. [PMID: 18023033 DOI: 10.1002/hed.20724] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
BACKGROUND Nasopharyngeal carcinoma (NPC) is associated with Epstein-Barr virus (EBV) and has high metastatic potential. Discoidin domain receptors (DDR1, DDR2) are receptor-type tyrosine kinases activated by collagen. Their ability to induce expression of matrix metalloproteinase is related with tumor invasion. Therefore, we aim to investigate DDRs gene expression and its regulation in NPC. METHODS AND RESULTS By use of real-time quantitative polymerase chain reaction (Q-PCR), DDR2 gene expression but not DDR1 was significantly higher in primary and metastatic NPC. DDR2 was predominantly distributed in NPC tumor cells rather than in infiltrating lymphocytes. EBV Z-transactivator (Zta) transfection may distinctly elevate DDR2 level. Furthermore, data from reporter assay indicate that Zta could transactivate DDR2 promoter activity, suggesting the possible upregulation mechanism. CONCLUSION DDR2 was differentially upregulated in NPC and modulated by EBV Zta protein. DDR2 may play a role in NPC invasion and serve as a diagnostic and therapeutic target.
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Affiliation(s)
- Huey-Huey Chua
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Number 1, Jen-Ai Road, Section 1, Taipei 10051, Taiwan, Republic of China.
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20
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Yang PW, Chang SS, Tsai CH, Chao YH, Chen MR. Effect of phosphorylation on the transactivation activity of Epstein-Barr virus BMRF1, a major target of the viral BGLF4 kinase. J Gen Virol 2008; 89:884-895. [PMID: 18343828 DOI: 10.1099/vir.0.83546-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Modification of human herpesvirus DNA polymerase processivity factors (PFs) by phosphorylation occurs frequently during viral lytic replication. However, functional regulation of the herpesvirus PFs through phosphorylation is not well understood. In addition to processivity, the PF BMRF1 of Epstein-Barr virus can function as a transactivator to activate the BHLF1 promoter within the lytic origin of replication (oriLyt), which is assumed to facilitate DNA replication through remodelling viral chromatin structure. BMRF1 is known to be phosphorylated by the viral BGLF4 kinase, but its impact on BMRF1 function is unclear. Seven candidate BGLF4 target sites were predicted within a proline-rich region between the DNA-processivity and nuclear-localization domains of BMRF1. We show that four of these residues, Ser-337, Thr-344, Ser-349 and Thr-355, are responsible for the BGLF4-induced hyperphosphorylation of BMRF1. In functional analyses, a phosphorylation-mimicking mutant of BMRF1 shows similar nuclear localization, as well as DNA-binding ability, to the wild type; however, it displays stronger synergistic activation of the BHLF1 promoter with Zta. Notably, BGLF4 downregulates BMRF1 transactivation and enhances the transactivation activity of Zta and the synergistic activation of BMRF1 and Zta on the BHLF1 promoter. Our findings suggest that BGLF4 may modulate the activation of the oriLyt BHLF1 promoter coordinately through multiple mechanisms to facilitate optimal oriLyt-dependent viral DNA replication.
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Affiliation(s)
- Pei-Wen Yang
- Graduate Institute and Department of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan, ROC
| | - Shih-Shin Chang
- Graduate Institute and Department of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan, ROC
| | - Ching-Hwa Tsai
- Graduate Institute and Department of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan, ROC
| | - Yi-Hsin Chao
- Graduate Institute and Department of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan, ROC
| | - Mei-Ru Chen
- Graduate Institute and Department of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan, ROC
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21
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Epstein-Barr virus lytic transactivator Zta enhances chemotactic activity through induction of interleukin-8 in nasopharyngeal carcinoma cells. J Virol 2008; 82:3679-88. [PMID: 18234802 DOI: 10.1128/jvi.02301-07] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Epstein-Barr virus (EBV)-associated, undifferentiated type of nasopharyngeal carcinoma (NPC) is characterized by intensive leukocyte infiltration. Interaction between the infiltrating cells and the tumor cells has been considered crucial for NPC development. Recruitment of the infiltrates can be directed by certain chemokines present in the NPC tissues. It is unknown whether and how EBV lytic infection regulates expression of the chemokines. Using an antibody array, we first found that several chemokines secreted from EBV-infected NPC cells are increased upon EBV reactivation into the lytic cycle, and interleukin-8 (IL-8) is the chemokine upregulated most significantly and consistently. Further studies showed that the EBV lytic transactivator Zta is a potent inducer of IL-8 in NPC cells, augmenting secreted and intracellular IL-8 proteins, as well as IL-8 RNA. Zta upregulates Egr-1, a cellular transcription factor that has been involved in upregulation of IL-8, but the Zta-induced IL-8 expression is independent of Egr-1. The ability of Zta to transactivate the IL-8 promoter is important for the induction of IL-8, and we have identified two Zta-responsive elements in the promoter. Zta can bind to these two elements in vitro and can also be recruited to the IL-8 promoter in vivo. DNA-binding-defective Zta mutants can neither activate the IL-8 promoter nor induce IL-8 production. In addition, Zta-expressing NPC cells exert enhanced chemotactic activity that is mainly mediated by IL-8. Since IL-8 may contribute to not only leukocyte infiltration but also multiple oncogenic processes, the present study provides a potential link between EBV lytic infection and pathogenesis of NPC.
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22
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Lin JH, Tsai CH, Chu JS, Chen JY, Takada K, Shew JY. Dysregulation of HER2/HER3 signaling axis in Epstein-Barr virus-infected breast carcinoma cells. J Virol 2007; 81:5705-13. [PMID: 17376931 PMCID: PMC1900270 DOI: 10.1128/jvi.00076-07] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The role of Epstein-Barr virus (EBV) in the pathogenesis of breast cancer has been of long-standing interest to the field. Breast epithelial cells can be infected by EBV through direct contact with EBV-bearing lymphoblastoid cells, and EBV infection has recently been shown to confer breast cancer cells an increased resistance to chemotherapeutic drugs. In this study, we established EBV-infected breast cancer MCF7 and BT474 cells and demonstrated that EBV infection promotes tumorigenic activity of breast cancer cells. Firstly, we showed that the EBV-infected MCF7-A and BT474-A cells exhibited increased anchorage-independent growth in soft agar. The increased colony formation capacity in soft agar was associated with increased expression and activation of HER2/HER3 signaling cascades, as evidenced by the findings that the treatment of HER2 antibody trastuzumab (Herceptin), phosphatidylinositol 3-kinase inhibitor, or MEK inhibitor completely abolished the tumorigenic capacity. In the EBV-infected breast cancer cells, the expression of EBV latency genes including EBNA1, EBER1, and BARF0 was detected. We next showed that BARF0 alone was sufficient to efficiently up-regulate HER2/HER3 expression and promoted tumorigenic activity in MCF7 and BT474 cells by the use of both overexpression and small interfering RNA knock-down. Collectively, we demonstrated that EBV-encoded BARF0 promotes the tumorigenic activity of breast cancer cells through activation of HER2/HER3 signaling cascades.
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Affiliation(s)
- Jiun-Han Lin
- Graduate Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei 10051, Taiwan
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23
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Chang Y, Lee HH, Chen YT, Lu J, Wu SY, Chen CW, Takada K, Tsai CH. Induction of the early growth response 1 gene by Epstein-Barr virus lytic transactivator Zta. J Virol 2006; 80:7748-55. [PMID: 16840354 PMCID: PMC1563714 DOI: 10.1128/jvi.02608-05] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Early growth response 1 (Egr-1) is a cellular transcription factor involved in diverse biologic functions. Egr-1 has been associated with Epstein-Barr virus (EBV) infection, but it is still unknown whether any EBV protein regulates Egr-1 expression. In this study, we first showed that EBV reactivation is involved in upregulation of Egr-1 and that Egr-1 can be induced by Zta, an EBV lytic transactivator. Zta not only binds to the Egr-1 promoter but also activates the ERK signaling pathway to trigger binding of Elk-1 to the Egr-1 promoter. In addition, knockdown of Egr-1 significantly reduces the spontaneous expression of Zta and Rta in EBV-infected 293 cells, suggesting that a positive-feedback network involving Egr-1 is required for EBV reactivation. This study also implies that Zta has the potential to affect expression of certain genes through Egr-1.
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Affiliation(s)
- Yao Chang
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Number 1, Section 1 Jen-Ai Road, Taipei, Taiwan
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24
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Lu J, Lin WH, Chen SY, Longnecker R, Tsai SC, Chen CL, Tsai CH. Syk tyrosine kinase mediates Epstein-Barr virus latent membrane protein 2A-induced cell migration in epithelial cells. J Biol Chem 2006; 281:8806-14. [PMID: 16431925 DOI: 10.1074/jbc.m507305200] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Although spleen tyrosine kinase (Syk) is known to be important in hematopoietic cell development, the roles of Syk in epithelial cells have not been well studied. Limited data suggest that Syk plays alternate roles in carcinogenesis under different circumstances. In breast cancer, Syk has been suggested to be a tumor suppressor. In contrast, Syk is essential for murine mammary tumor virus-mediated transformation. However, the roles of Syk in tumor migration are still largely unknown. Nasopharyngeal carcinoma, an unusually highly metastatic tumor, expresses Epstein-Barr virus LMP2A (latent membrane protein 2A) in most clinical specimens. Previously, we demonstrated LMP2A triggers epithelial cell migration. LMP2A contains an immunoreceptor tyrosine-based activation motif, which is important for Syk kinase activation in B cells. In this study, we explored whether Syk is important for LMP2A-mediated epithelial cell migration. We demonstrate that LMP2A expression can activate endogenous Syk activity. The activation requires the tyrosine residues in LMP2A ITAM but not YEEA motif, which is important for Syk activation by Lyn in B cells. LMP2A interacts with Syk as demonstrated by coimmunoprecipitation and confocal microscopy. Furthermore, LMP2A-induced cell migration is inhibited by a Syk inhibitor and short interfering RNA. Tyrosines 74 and 85 in the LMP2A immunoreceptor tyrosine-based activation motif are essential for both Syk activation and LMP2A-mediated cell migration, indicating the involvement of Syk in LMP2A-triggered cell migration. The LMP2A-Syk pathway may provide suitable drug targets for treatment of nasopharyngeal carcinoma.
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Affiliation(s)
- Jean Lu
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei 10063, Taiwan
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25
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Chang Y, Chang SS, Lee HH, Doong SL, Takada K, Tsai CH. Inhibition of the Epstein–Barr virus lytic cycle by Zta-targeted RNA interference. J Gen Virol 2004; 85:1371-1379. [PMID: 15166418 DOI: 10.1099/vir.0.79886-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Epstein–Barr virus (EBV) reactivation into the lytic cycle plays certain roles in the development of EBV-associated diseases, so an effective strategy to block the viral lytic cycle may be of value to reduce the disease risk or to improve the clinical outcome. This study examined whether the EBV lytic cycle could be inhibited using RNA interference (RNAi) directed against the essential viral gene Zta. In cases of EBV reactivation triggered by chemicals or by exogenous Rta, Zta-targeted RNAi prevented the induction of Zta and its downstream genes and further blocked the lytic replication of viral genomes. This antiviral effect of RNAi was not likely to be mediated by activation of the interferon pathway, as phosphorylation of STAT1 was not induced. In addition, novel EBV-infected epithelial cells showing constitutive activation of the lytic cycle were cloned; such established lytic infection was also suppressed by Zta-targeted RNAi. These results indicate that RNAi can be used to inhibit the EBV lytic cycle effectively in vitro and could also be of potential use to develop anti-EBV treatments.
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Affiliation(s)
- Yao Chang
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Room 714, Number 1, Section 1, Jen-Ai Road, Taipei, Taiwan
| | - Shih-Shin Chang
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Room 714, Number 1, Section 1, Jen-Ai Road, Taipei, Taiwan
| | - Heng-Huan Lee
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Room 714, Number 1, Section 1, Jen-Ai Road, Taipei, Taiwan
| | - Shin-Lian Doong
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Room 714, Number 1, Section 1, Jen-Ai Road, Taipei, Taiwan
| | - Kenzo Takada
- Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan
| | - Ching-Hwa Tsai
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Room 714, Number 1, Section 1, Jen-Ai Road, Taipei, Taiwan
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26
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Abstract
The human gammaherpesviruses Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) both infect lymphoid and epithelial cells and both are implicated in the development of cancer. The two viruses establish latency in B-lymphoid cells that, once disrupted, leads to a burst of virus replication during the lytic cycle. A basic leucine zipper (bZIP) transcription factor encoded by EBV, Zta (also known as BZLF1 and ZEBRA), is key to the disruption of EBV latency. KSHV encodes a related protein, K-bZIP (also known as RAP and K8alpha). Recent developments in our understanding of the structures and functions of these two viral bZIP proteins have led to the conclusion that they are not homologues. Two important features of Zta are its ability to interact directly with DNA and to induce EBV replication whereas K-bZIP is not known to interact directly with DNA or to induce KSHV replication. Despite these differences, the ability to disrupt cell cycle control is conserved in both Zta and K-bZIP. The interactions of Zta and K-bZIP with cellular genes will be reviewed here.
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Affiliation(s)
- Alison J Sinclair
- School of Biological Sciences, University of Sussex, Brighton, East Sussex BN1 9QG, UK
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27
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Mahot S, Sergeant A, Drouet E, Gruffat H. A novel function for the Epstein-Barr virus transcription factor EB1/Zta: induction of transcription of the hIL-10 gene. J Gen Virol 2003; 84:965-974. [PMID: 12655098 DOI: 10.1099/vir.0.18845-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Interleukin-10 (IL-10) plays a critical role in Epstein-Barr virus (EBV) biology. Indeed, the EBV genome contains a gene (BCRF1) with homology to the human IL-10 (hIL-10) gene. In addition to viral IL-10, which is secreted late in the productive cycle, hIL-10 production is also induced in B cells infected by EBV. The EBV protein LMP-1 and the viral small non-polyadenylated RNAs (EBERs) expressed during latency are involved in hIL-10 induction. In this study, we show that in B cells the viral transcription factor EB1, which is the main inducer of the EBV productive cycle, also activates transcription of the hIL-10 gene and secretion of the hIL-10 protein. Accordingly, EB1 bound directly to specific DNA sequences in the hIL-10 minimal promoter. Moreover, specific disruption of EB1 binding to some of these sites impaired EB1-mediated activation of transcription at the hIL-10 promoter in a transient expression assay. Therefore, an increase in IL-10 production occurs during latency and early and late during the productive cycle. This production of IL-10 might favour the survival of EBV-infected cells in vivo and/or create a microenvironment required for efficient de novo infection of B lymphocytes by EBV virions.
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Affiliation(s)
- Segolene Mahot
- Laboratoire de Virologie Moléculaire et Structurale, UPRES-EA2939, GDR CNRS 2372, Université Joseph-Fourier Grenoble I, 38706 La Tronche, France
| | - Alain Sergeant
- U412 INSERM, ENS-Lyon, 46 allée d'Italie, 69364 Lyon Cedex 07, France
| | - Emmanuel Drouet
- Laboratoire de Virologie Moléculaire et Structurale, UPRES-EA2939, GDR CNRS 2372, Université Joseph-Fourier Grenoble I, 38706 La Tronche, France
| | - Henri Gruffat
- U412 INSERM, ENS-Lyon, 46 allée d'Italie, 69364 Lyon Cedex 07, France
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