scholarly journals Essential role of PKCδ in histone deacetylase inhibitor-induced Epstein–Barr virus reactivation in nasopharyngeal carcinoma cells

2008 ◽  
Vol 89 (4) ◽  
pp. 878-883 ◽  
Author(s):  
Heng-Huan Lee ◽  
Shih-Shin Chang ◽  
Sue-Jane Lin ◽  
Huey-Huey Chua ◽  
Tze-Jiun Tsai ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Epstein Barr Virus ◽  
Nuclear Translocation ◽  
Chemotherapeutic Agents ◽  
Lytic Cycle ◽  
Virus Reactivation ◽  
Barr Virus ◽  
Ebv Reactivation ◽  
Deacetylase Inhibitor ◽  
Epstein Barr

Histone deactylase inhibitors (HDACi) are common chemotherapeutic agents that stimulate Epstein–Barr virus (EBV) reactivation; the detailed mechanism remains obscure. In this study, it is demonstrated that PKCδ is required for induction of the EBV lytic cycle by HDACi. Inhibition of PKCδ abrogates HDACi-mediated transcriptional activation of the Zta promoter and downstream lytic gene expression. Nuclear translocation of PKCδ is observed following HDACi stimulation and its overexpression leads to progression of the EBV lytic cycle. Our study suggests that PKCδ is a crucial mediator of EBV reactivation and provides a novel insight to study the regulation of the EBV lytic cycle.

scholarly journals Cytolytic Epstein-Barr Virus Reactivation Therapy for EBV-Associated Gastric Carcinoma

2020 ◽  
pp. 1-10
Author(s):  
Jaap M. Middeldorp ◽  
Zlata Novalić ◽  
Sandra A.W.M. Verkuijlen ◽  
Astrid E. Greijer ◽  
Jaap M. Middeldorp
Keyword(s):  
Gastric Carcinoma ◽  
Mouse Model ◽  
Cell Lines ◽  
Epstein Barr Virus ◽  
Drug Combinations ◽  
Model Systems ◽  
Virus Reactivation ◽  
Barr Virus ◽  
Ebv Reactivation ◽  
Epstein Barr

Background: Epstein-Barr virus associated gastric carcinoma (EBVaGC) is considered a distinct GC disease entity, with the virus persisting in a latent phase. Treatment with Epirubicin, Capecitabine and Cisplatin (ECC combination) showed survival benefit in patients with GC in clinical trials (MAGIC study and CRITICS study) when compared to chemotherapy with Capecitabine and Cisplatin (GCb/Cis). Current treatment protocols for GC do not consider virus involvement. Methods: In this study, we tested a CytoLytic Virus Activation (CLVA) strategy consisting of the ECC combination or GCb/Cis together with the HDAC inhibitor Valproic acid (VPA) to define whether EBV reactivation and subsequent antiviral treatment with Ganciclovir (GCV) could be used as virus-targeted therapy for EBVaGC. Drug combinations with VPA and GCV were evaluated in multiple cell lines and in an EBVaGC mouse model based on human naturally EBV-infected SNU-719 cells. Results: EBV reactivation was demonstrated by lytic mRNA transcripts and proteins in treated cells, and the virus-reactivating capacity of different CLVA drug combinations was compared in C666.1, AGS-BX1 and SNU-719 cell lines. In an EBVaGC mouse model, GCb/Cis with VPA and GCV strongly reduced tumor volume and showed the highest potential for EBV-reactivation. Upon a single round of CLVA treatment, EBV DNA levels in circulation decreased, and loss of EBV-positive cells in treated tumors was observed. In vivo EBV-reactivation was revealed by the presence of lytic gene transcripts and proteins in tumor tissues 6 days after treatment. Conclusion: In EBVaGC model systems, CLVA treatment showed a more potent virus reactivation and killing of tumor cells when compared to standard chemotherapy alone, suggesting that addition of VPA plus GCV to the ECC or GCb/Cis combination should be considered in future clinical studies.

scholarly journals Clinical characteristics and outcomes of critically ill patients with acute COVID-19 with Epstein-Barr virus reactivation

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Yun Xie ◽  
Song Cao ◽  
Hui Dong ◽  
Hui Lv ◽  
Xiaolei Teng ◽  
...  
Keyword(s):  
Epstein Barr Virus ◽  
Mortality Rates ◽  
Virus Reactivation ◽  
Barr Virus ◽  
Ebv Reactivation ◽  
Imaging Characteristics ◽  
Single Center Study ◽  
Significant Difference ◽  
Epstein Barr ◽  
Epstein Barr Virus Reactivation

Abstract Background Our goal is to further elucidate the clinical condition and prognosis of patients with severe acute COVID-19 with EBV reactivation. Method This is a retrospective single-center study of COVID-19 patients admitted to the intensive care unit of Wuhan No. 3 Hospital (January 31 to March 27, 2020). According to whether Epstein-Barr virus reactivation was detected, the patients were divided into an EBV group and a Non-EBV group. Baseline data were collected including epidemiological, larithmics, clinical and imaging characteristics, and laboratory examination data. Results Of the 128 patients with COVID-19, 17 (13.3%) were infected with Epstein-Barr virus reactivation. In the symptoms,the rate of tachypnoea in the EBV group was apparently higher than that in the Non-EBV group. In lab tests, the lymphocyte and albumin of EBV group decreased more significantly than Non-EBV group, and the D-dimer and serum calcium of EBV group was higher than Non-EBV group. Regarding the infection index, CRP of EBV group was apparently above the Non-EBV group, and no significant difference was found in procalcitonin of the two groups. The incidence of respiratory failure, ARDS, and hypoproteinaemia of EBV group had more incidence than Non-EBV group. The 28-day and 14-day mortality rates of EBV group was significantly higher than that of Non-EBV group. Conclusions In the COVID-19 patients, patients with EBV reactivation had higher 28-day and 14-day mortality rates and received more immuno-supportive treatment than patients of Non-EBV group.

scholarly journals An Absence of Epstein–Barr Virus Reactivation and Associations with Disease Activity in People with Multiple Sclerosis Undergoing Therapeutic Hookworm Vaccination

Vaccines ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 487
Author(s):  
Peter A. C. Maple ◽  
Bruno Gran ◽  
Radu Tanasescu ◽  
David I. Pritchard ◽  
Cris S. Constantinescu
Keyword(s):  
Multiple Sclerosis ◽  
Disease Activity ◽  
Epstein Barr Virus ◽  
Nuclear Antigen ◽  
Virus Reactivation ◽  
Serum Samples ◽  
Barr Virus ◽  
Ebv Infection ◽  
Ebv Reactivation ◽  
Epstein Barr

Background: Epstein–Barr virus (EBV) infection is strongly associated with multiple sclerosis (MS). Helminth infection can downregulate antiviral immune responses, potentially protecting against MS, but with a theoretical risk for reactivating latent EBV infection. Objective: To investigate parameters of EBV infection and their relationship with disease activity in people with MS (PwMS) therapeutically vaccinated with Necator americanus (hookworm). Methods: Sequential serum samples from 51 PwMS; 26 therapeutically infected (25 larvae) with N. americanus and 25 controls were tested for EBV virus capsid antigen (VCA) IgG and IgM, EBV nuclear antigen-1 (EBNA-1) IgG, and EBV early antigen (EA) IgG. Disease activity was assessed by periodic MRI. Significance was set at p < 0.05. Results: All PwMS were EBV VCA IgG and EBNA-1 IgG positive, and 35.2% were EBV EA IgG positive. EBV antibody levels were generally stable, and EBV reactivation in PwMS was not demonstrated by significant increases in IgG titre over 12 months. Disease activity was most frequent in PwMS possessing high levels of EBV VCA IgG (>600 units/mL) or EBNA-1 IgG (>150 units/mL); however, there was no association with hookworm treatment. Interpretation: Therapeutic hookworm vaccination was not associated with EBV reactivation. Multiple sclerosis disease activity was associated with high levels of EBV VCA IgG or EBNA-1 IgG.

scholarly journals Marked Variation in Response of Consensus Binding Elements for the Rta Protein of Epstein-Barr Virus

2005 ◽  
Vol 79 (15) ◽  
pp. 9635-9650 ◽  
Author(s):  
Lee-Wen Chen ◽  
Pey-Jium Chang ◽  
Henri-Jacques Delecluse ◽  
George Miller
Keyword(s):  
Dna Sequences ◽  
Transcriptional Activation ◽  
Mammalian Cells ◽  
Epstein Barr Virus ◽  
Lytic Cycle ◽  
Maximal Response ◽  
Binding Affinities ◽  
Barr Virus ◽  
Epstein Barr

ABSTRACT The R transactivator (Rta) protein activates Epstein-Barr virus (EBV) lytic-cycle genes by several distinct mechanisms that include direct binding to viral promoters, synergy with BamHI Z EBV replication activator (ZEBRA), and activation of cellular signaling pathways. In the direct and synergistic mechanisms of action, Rta binds to specific DNA sequences that are present in the promoters of responsive genes. It has been difficult to demonstrate the capacity of Rta expressed in mammalian cells to bind DNA in vitro in order to study the relative affinities of Rta binding elements. We discovered that a short C-terminal region of Rta inhibits the ability of Rta to bind DNA in vitro. C-terminally truncated versions of Rta bind DNA efficiently and thus facilitate a comparison of consensus Rta binding elements (CRBEs) found in promoters of five Rta-responsive genes: BMLF1, BHLF1, BMRF1, BaRF1, and BLRF2. All CRBEs in the promoters of the five genes conform to the proposed recognition sequence GNCCN9GGNG, where N is any nucleotide and N9 represents a sequence of nine nucleotides. Nonetheless, CRBEs varied markedly in their abilities to bind Rta in electrophoretic mobility shift assays. Not all CRBEs bound or responded to Rta. Binding affinities of the CRBEs and the capacity to be activated by Rta in reporter assays were strongly correlated. The CRBEs from the BMLF1 and BHLF1 promoters conferred the greatest response. The response of the BMRF1, BaRF1, and BLRF2 CRBEs was less robust. By creation of chimeras, inversions, and point mutations, differences in binding affinities and transcriptional activation levels could be attributed to N9 sequence variation. The length of N9 was also critical for a maximal response. In Raji and BZLF1-knockout cells, the mRNAs of the five Rta-responsive lytic-cycle genes differed dramatically in kinetics of expression, abundance, and synergistic responses to ZEBRA and Rta. Affinities of Rta response elements for Rta are likely to play an important role in temporal regulation and the level of lytic-cycle EBV gene expression.

scholarly journals Induction of Epstein-Barr Virus Latent Membrane Protein 1 by a Lytic Transactivator Rta

2004 ◽  
Vol 78 (23) ◽  
pp. 13028-13036 ◽  
Author(s):  
Yao Chang ◽  
Heng-Huan Lee ◽  
Shih-Shin Chang ◽  
Tsuey-Ying Hsu ◽  
Pei-Wen Wang ◽  
...  
Keyword(s):  
Membrane Protein ◽  
Epstein Barr Virus ◽  
Latent Membrane Protein ◽  
Lytic Cycle ◽  
Immediate Early ◽  
Latent Membrane Protein 1 ◽  
Virus Reactivation ◽  
Barr Virus ◽  
Lmp1 Expression ◽  
Epstein Barr

ABSTRACT Latent membrane protein 1 (LMP1) of Epstein-Barr virus (EBV) is a transforming protein that affects multiple cell signaling pathways and contributes to EBV-associated oncogenesis. LMP1 can be expressed in some states of EBV latency, and significant induction of full-length LMP1 is also observed frequently during virus reactivation into the lytic cycle. It is still unknown how LMP1 expression is regulated during the lytic stage and whether any EBV lytic protein is involved in the induction of LMP1. In this study, we first identified that LMP1 expression is associated with the spontaneous virus reactivation in EBV-infected 293 cells and that its expression is a downstream event of the lytic cycle. We further found that LMP1 can be induced by ectopic expression of Rta, an EBV immediate-early lytic protein. The Rta-mediated LMP1 induction is independent of another immediate-early protein, Zta. Northern blotting and reverse transcription-PCR analysis revealed that Rta upregulates LMP1 at the RNA level. Reporter gene assays further demonstrated that Rta activates both the proximal and distal promoters of the LMP1 gene in EBV-negative cells. Both the amino and carboxyl termini of the Rta protein are required for the induction of LMP1. In addition, Rta transactivates LMP1 not only in epithelial cells but also in B-lymphoid cells. This study reveals a new mechanism to upregulate LMP1 expression, expanding the knowledge of LMP1 regulation in the EBV life cycle. Considering an equivalent case of Kaposi's sarcoma-associated herpesvirus, induction of a transforming membrane protein by a key lytic transactivator during virus reactivation is likely to be a conserved event for gammaherpesviruses.

scholarly journals Identification of ARKL1 as a Negative Regulator of Epstein-Barr Virus Reactivation

2019 ◽  
Vol 93 (20) ◽  
Author(s):  
Umama Z. Siddiqi ◽  
Anup S. Vaidya ◽  
Xinliu Li ◽  
Edyta Marcon ◽  
Sai Wah Tsao ◽  
...  
Keyword(s):  
Epstein Barr Virus ◽  
Lytic Cycle ◽  
Negative Regulator ◽  
Regulatory Subunit ◽  
Ags Cells ◽  
Barr Virus ◽  
Ebv Reactivation ◽  
Reporter Assays ◽  
Epstein Barr ◽  
Factor C

ABSTRACT Epstein-Barr virus (EBV) maintains a life-long infection due to the ability to alternate between latent and lytic modes of replication. Lytic reactivation starts with derepression of the Zp promoter controlling BZLF1 gene expression, which binds and is activated by the c-Jun transcriptional activator. Here, we identified the cellular Arkadia-like 1 (ARKL1) protein as a negative regulator of Zp and EBV reactivation. Silencing of ARKL1 in the context of EBV-positive gastric carcinoma (AGS) cells, nasopharyngeal carcinoma (NPC43) cells, and B (M81) cells led to increased lytic protein expression, whereas overexpression inhibited BZLF1 expression. Similar effects of ARKL1 modulation were seen on BZLF1 transcripts as well as on Zp activity in Zp reporter assays, showing that ARKL1 repressed Zp. Proteomic profiling of ARKL1-host interactions identified c-Jun as an ARKL1 interactor, and reporter assays for Jun transcriptional activity showed that ARKL1 inhibited Jun activity. The ARKL1-Jun interaction required ARKL1 sequences that we previously showed mediated binding to the CK2 kinase regulatory subunit CK2β, suggesting that CK2β might mediate the ARKL1-Jun interaction. This model was supported by the findings that silencing of CK2β, but not the CK2α catalytic subunit, abrogated the ARKL1-Jun interaction and phenocopied ARKL1 silencing in promoting EBV reactivation. Additionally, ARKL1 was associated with Zp in reporter assays and this was increased by additional CK2β. Together, the data indicate that ARKL1 is a negative regulator of Zp and EBV reactivation that acts by inhibiting Jun activity through a CK2β-mediated interaction. IMPORTANCE Epstein-Barr virus (EBV) maintains a life-long infection due to the ability to alternate between latent and lytic modes of replication and is associated with several types of cancer. We have identified a cellular protein (ARKL1) that acts to repress the reactivation of EBV from the latent to the lytic cycle. We show that ARKL1 acts to repress transcription of the EBV lytic switch protein by inhibiting the activity of the cellular transcription factor c-Jun. This not only provides a new mechanism of regulating EBV reactivation but also identifies a novel cellular function of ARKL1 as an inhibitor of Jun-mediated transcription.

scholarly journals Critical Role of p53 in Histone Deacetylase Inhibitor-Induced Epstein-Barr Virus Zta Expression

2008 ◽  
Vol 82 (15) ◽  
pp. 7745-7751 ◽  
Author(s):  
Shih-Shin Chang ◽  
You-Chang Lo ◽  
Huey-Huey Chua ◽  
Hsin-Yi Chiu ◽  
Shu-Chun Tsai ◽  
...  
Keyword(s):  
Histone Deacetylase ◽  
Histone Deacetylase Inhibitor ◽  
Epstein Barr Virus ◽  
Critical Role ◽  
Suppressor Gene ◽  
Lytic Cycle ◽  
Barr Virus ◽  
Deacetylase Inhibitor ◽  
Reporter Assays ◽  
Epstein Barr

ABSTRACT The tumor suppressor gene p53 plays a central role in the maintenance of normal cell growth and genetic integrity, while its impact on the Epstein-Barr virus (EBV) life cycle remains elusive. We found that p53 is important for histone deacetylase inhibitor-induced EBV lytic gene expression in nasopharyngeal carcinoma cells. Restoration of p53 in p53-null, EBV-infected H1299 cells augments the potential for viral lytic cycle initiation. Evidence from reporter assays demonstrated that p53 contributes to the expression of the immediate-early viral Zta gene. Further analysis indicated that the DNA-binding ability of p53 and phosphorylation of Ser392 may be critical. This study provides the first evidence that p53 is involved in the regulation of EBV lytic cycle initiation.

scholarly journals Inhibition of the Epstein–Barr virus lytic cycle by Zta-targeted RNA interference

2004 ◽  
Vol 85 (6) ◽  
pp. 1371-1379 ◽  
Author(s):  
Yao Chang ◽  
Shih-Shin Chang ◽  
Heng-Huan Lee ◽  
Shin-Lian Doong ◽  
Kenzo Takada ◽  
...  
Keyword(s):  
Rna Interference ◽  
Epstein Barr Virus ◽  
Disease Risk ◽  
Lytic Replication ◽  
Lytic Cycle ◽  
Viral Gene ◽  
Barr Virus ◽  
Ebv Reactivation ◽  
Epstein Barr

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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