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  1. Article: Nelfinavir inhibition of Kaposi's sarcoma-associated herpesvirus protein expression and capsid assembly.

    Li, Maggie / Smith, Barbara J / Lee, Jaeyeun / Petr, Jennifer / Anders, Nicole M / Wiseman, Robyn / Rudek, Michelle A / Ambinder, Richard F / Desai, Prashant J

    Infectious agents and cancer

    2024  Volume 19, Issue 1, Page(s) 7

    Abstract: Background: Antiviral therapies that target herpesviruses are clinically important. Nelfinavir is a protease inhibitor that targets the human immunodeficiency virus (HIV) aspartyl protease. Previous studies demonstrated that this drug could also inhibit ...

    Abstract Background: Antiviral therapies that target herpesviruses are clinically important. Nelfinavir is a protease inhibitor that targets the human immunodeficiency virus (HIV) aspartyl protease. Previous studies demonstrated that this drug could also inhibit Kaposi's sarcoma-associated herpesvirus (KSHV) production. Our laboratory demonstrated nelfinavir can effectively inhibit herpes simplex virus type 1 (HSV-1) replication. For HSV-1 we were able to determine that virus capsids were assembled and exited the nucleus but did not mature in the cytoplasm indicating the drug inhibited secondary envelopment of virions.
    Methods: For KSHV, we recently derived a tractable cell culture system that allowed us to analyze the virus replication cycle in greater detail. We used this system to further define the stage at which nelfinavir inhibits KSHV replication.
    Results: We discovered that nelfinavir inhibits KSHV extracellular virus production. This was seen when the drug was incubated with the cells for 3 days and when we pulsed the cells with the drug for 1-5 min. When KSHV infected cells exposed to the drug were examined using ultrastructural methods there was an absence of mature capsids in the nucleus indicating a defect in capsid assembly. Because nelfinavir influences the integrated stress response (ISR), we examined the expression of viral proteins in the presence of the drug. We observed that the expression of many were significantly changed in the presence of drug. The accumulation of the capsid triplex protein, ORF26, was markedly reduced. This is an essential protein required for herpesvirus capsid assembly.
    Conclusions: Our studies confirm that nelfinavir inhibits KSHV virion production by disrupting virus assembly and maturation. This is likely because of the effect of nelfinavir on the ISR and thus protein synthesis and accumulation of the essential triplex capsid protein, ORF26. Of interest is that inhibition requires only a short exposure to drug. The source of infectious virus in saliva has not been defined in detail but may well be lymphocytes or other cells in the oral mucosa. Thus, it might be that a "swish and spit" exposure rather than systemic administration would prevent virion production.
    Language English
    Publishing date 2024-03-04
    Publishing country England
    Document type Journal Article
    ZDB-ID 2251117-9
    ISSN 1750-9378
    ISSN 1750-9378
    DOI 10.1186/s13027-024-00566-7
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Arsenicals, the Integrated Stress Response, and Epstein-Barr Virus Lytic Gene Expression.

    Lee, Jaeyeun / Stone, Jennifer / Desai, Prashant / Kosowicz, John G / Liu, Jun O / Ambinder, Richard F

    Viruses

    2021  Volume 13, Issue 5

    Abstract: Following our observation that clofoctol led to Epstein-Barr virus (EBV) lytic gene expression upon activation of the integrated stress response (ISR), we decided to investigate the impact of ... ...

    Abstract Following our observation that clofoctol led to Epstein-Barr virus (EBV) lytic gene expression upon activation of the integrated stress response (ISR), we decided to investigate the impact of As
    MeSH term(s) Arsenicals/pharmacology ; Biomarkers ; Cell Line, Tumor ; Cells, Cultured ; Epstein-Barr Virus Infections/genetics ; Epstein-Barr Virus Infections/virology ; Herpesvirus 4, Human/drug effects ; Host-Pathogen Interactions/drug effects ; Host-Pathogen Interactions/genetics ; Humans ; Models, Biological ; Stress, Physiological/drug effects ; Stress, Physiological/genetics ; Virus Activation ; Virus Replication/drug effects
    Chemical Substances Arsenicals ; Biomarkers
    Language English
    Publishing date 2021-04-30
    Publishing country Switzerland
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 2516098-9
    ISSN 1999-4915 ; 1999-4915
    ISSN (online) 1999-4915
    ISSN 1999-4915
    DOI 10.3390/v13050812
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article: Arsenicals, the Integrated Stress Response, and Epstein–Barr Virus Lytic Gene Expression

    Lee, Jaeyeun / Stone, Jennifer / Desai, Prashant / Kosowicz, John G / Liu, Jun O / Ambinder, Richard F

    Viruses. 2021 Apr. 30, v. 13, no. 5

    2021  

    Abstract: Following our observation that clofoctol led to Epstein–Barr virus (EBV) lytic gene expression upon activation of the integrated stress response (ISR), we decided to investigate the impact of As₂O₃ on viral lytic gene expression. As₂O₃ has also been ... ...

    Abstract Following our observation that clofoctol led to Epstein–Barr virus (EBV) lytic gene expression upon activation of the integrated stress response (ISR), we decided to investigate the impact of As₂O₃ on viral lytic gene expression. As₂O₃ has also been reported to activate the ISR pathway by its activation of the heme-regulated inhibitor (HRI). Our investigations show that As₂O₃ treatment leads to eIF2α phosphorylation, upregulation of ATF4 and TRB3 expression, and an increase of EBV Zta gene expression in lymphoid tumor cell lines as well as in naturally infected epithelial cancer cell lines. However, late lytic gene expression and virion production were blocked after arsenic treatment. In comparison, a small molecule HRI activator also led to increased Zta expression but did not block late lytic gene expression, suggesting that As₂O₃ effects on EBV gene expression are also mediated through other pathways.
    Keywords Human gammaherpesvirus 4 ; arsenic ; arsenicals ; epithelium ; gene expression ; neoplasm cells ; phosphorylation ; stress response ; virion
    Language English
    Dates of publication 2021-0430
    Publishing place Multidisciplinary Digital Publishing Institute
    Document type Article
    Note NAL-AP-2-clean
    ZDB-ID 2516098-9
    ISSN 1999-4915
    ISSN 1999-4915
    DOI 10.3390/v13050812
    Database NAL-Catalogue (AGRICOLA)

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  4. Article ; Online: Unveiling kaposi sarcoma viral antigens.

    Lee, Jaeyeun / Kosowicz, John G / Ambinder, Richard F

    Oncotarget

    2017  Volume 8, Issue 31, Page(s) 50325–50326

    Language English
    Publishing date 2017-07-08
    Publishing country United States
    Document type News ; Comment
    ZDB-ID 2560162-3
    ISSN 1949-2553 ; 1949-2553
    ISSN (online) 1949-2553
    ISSN 1949-2553
    DOI 10.18632/oncotarget.19106
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Pharmacologic Activation of Lytic Epstein-Barr Virus Gene Expression without Virion Production.

    Lee, Jaeyeun / Kosowicz, John G / Hayward, S Diane / Desai, Prashant / Stone, Jennifer / Lee, Jae Myun / Liu, Jun O / Ambinder, Richard F

    Journal of virology

    2019  Volume 93, Issue 20

    Abstract: Several therapeutic strategies targeting Epstein-Barr virus (EBV)-associated tumors involve upregulation of viral lytic gene expression. Evidence has been presented that the unfolded protein response (UPR) leads to EBV lytic gene expression. Clofoctol, ... ...

    Abstract Several therapeutic strategies targeting Epstein-Barr virus (EBV)-associated tumors involve upregulation of viral lytic gene expression. Evidence has been presented that the unfolded protein response (UPR) leads to EBV lytic gene expression. Clofoctol, an antibacterial antibiotic, has been reported to upregulate the UPR in prostate cancer cell lines and to slow their growth. We investigated the effects of clofoctol on an EBV-positive Burkitt lymphoma cell line and confirmed the upregulation of all three branches of the UPR and activation of EBV lytic gene expression. While immediate early, early, and late EBV RNAs were all upregulated, immediate early and early viral proteins but not late viral proteins were expressed. Furthermore, infectious virions were not produced. The use of clofoctol in combination with a protein kinase R-like endoplasmic reticulum kinase inhibitor led to expression of late viral proteins. The effects of clofoctol on EBV lytic protein upregulation were not limited to lymphoid tumor cell lines but also occurred in naturally infected epithelial gastric cancer and nasopharyngeal cancer cell lines. An agent that upregulates lytic viral protein expression but that does not lead to the production of infectious virions may have particular value for lytic induction strategies in the clinical setting.
    MeSH term(s) Biomarkers ; Cell Line, Tumor ; Epstein-Barr Virus Infections/metabolism ; Epstein-Barr Virus Infections/virology ; Gene Expression Regulation, Viral ; Herpesvirus 4, Human/drug effects ; Herpesvirus 4, Human/physiology ; Host-Pathogen Interactions ; Humans ; MAP Kinase Signaling System ; Proteasome Endopeptidase Complex/metabolism ; Stress, Physiological ; Unfolded Protein Response ; Viral Proteins/genetics ; Viral Proteins/metabolism ; Virus Activation/drug effects ; Virus Replication ; eIF-2 Kinase/antagonists & inhibitors
    Chemical Substances Biomarkers ; Viral Proteins ; EIF2AK3 protein, human (EC 2.7.11.1) ; eIF-2 Kinase (EC 2.7.11.1) ; Proteasome Endopeptidase Complex (EC 3.4.25.1)
    Language English
    Publishing date 2019-09-30
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 80174-4
    ISSN 1098-5514 ; 0022-538X
    ISSN (online) 1098-5514
    ISSN 0022-538X
    DOI 10.1128/JVI.00998-19
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Drug Modulators of B Cell Signaling Pathways and Epstein-Barr Virus Lytic Activation.

    Kosowicz, John G / Lee, Jaeyeun / Peiffer, Brandon / Guo, Zufeng / Chen, Jianmeng / Liao, Gangling / Hayward, S Diane / Liu, Jun O / Ambinder, Richard F

    Journal of virology

    2017  Volume 91, Issue 16

    Abstract: Epstein-Barr virus (EBV) is a ubiquitous human gammaherpesvirus that establishes a latency reservoir in B cells. In this work, we show that ibrutinib, idelalisib, and dasatinib, drugs that block B cell receptor (BCR) signaling and are used in the ... ...

    Abstract Epstein-Barr virus (EBV) is a ubiquitous human gammaherpesvirus that establishes a latency reservoir in B cells. In this work, we show that ibrutinib, idelalisib, and dasatinib, drugs that block B cell receptor (BCR) signaling and are used in the treatment of hematologic malignancies, block BCR-mediated lytic induction at clinically relevant doses. We confirm that the immunosuppressive drugs cyclosporine and tacrolimus also inhibit BCR-mediated lytic induction but find that rapamycin does not inhibit BCR-mediated lytic induction. Further investigation shows that mammalian target of rapamycin complex 2 (mTORC2) contributes to BCR-mediated lytic induction and that FK506-binding protein 12 (FKBP12) binding alone is not adequate to block activation. Finally, we show that BCR signaling can activate EBV lytic induction in freshly isolated B cells from peripheral blood mononuclear cells (PBMCs) and that activation can be inhibited by ibrutinib or idelalisib.
    MeSH term(s) B-Lymphocytes/drug effects ; B-Lymphocytes/virology ; Herpesvirus 4, Human/drug effects ; Herpesvirus 4, Human/physiology ; Humans ; Immunologic Factors/metabolism ; Receptors, Antigen, B-Cell/metabolism ; Signal Transduction/drug effects ; Virus Activation/drug effects
    Chemical Substances Immunologic Factors ; Receptors, Antigen, B-Cell
    Language English
    Publishing date 2017-08-15
    Publishing country United States
    Document type Journal Article
    ZDB-ID 80174-4
    ISSN 1098-5514 ; 0022-538X
    ISSN (online) 1098-5514
    ISSN 0022-538X
    DOI 10.1128/JVI.00747-17
    Database MEDical Literature Analysis and Retrieval System OnLINE

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