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Ghorbanzadeh Neghab M, Jalili-Nik M, Soltani A, Afshari AR, Hassanian SM, Rafatpanah H, Rezaee SA, Sadeghnia HR, Ataei Azimi S, Mashkani B. Rigosertib is more potent than wortmannin and rapamycin against adult T-cell leukemia-lymphoma. Biofactors 2023; 49:1174-1188. [PMID: 37345860 DOI: 10.1002/biof.1985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 06/09/2023] [Indexed: 06/23/2023]
Abstract
Human T lymphotropic virus type 1 (HTLV-1) infection can cause adult T-cell lymphoblastic leukemia (ATLL), an incurable, chemotherapy-resistant malignancy. In a quest for new therapeutic targets, our study sought to determine the levels of AKT, mTOR, and PI3K in ATLL MT-2 cells, HTLV-1 infected NIH/3T3 cells (Inf-3T3), and HTLV-1 infected patients (Carrier, HAM/TSP, and ATLL). Furthermore, the effects of rigosertib, wortmannin, and rapamycin on the PI3K/Akt/mTOR pathway to inhibit the proliferation of ATLL cells were examined. The results showed that mRNA expression of Akt/PI3K/mTOR was down-regulated in carrier, HAM/TSP, and ATLL patients, as well as MT-2, and Inf-3T3 cells, compared to the healthy individuals and untreated MT-2 and Inf-3T3 as controls. However, western blotting revealed an increase in the phosphorylated and activated forms of AKT and mTOR. Treating the cells with rapamycin, wortmannin, and rigosertib decreased the phosphorylated forms of Akt and mTOR and restored their mRNA expression levels. Using these inhibitors also significantly boosted the expression of the pro-apoptotic genes, Bax/Bcl-2 ratio as well as the expression of the tumor suppressor gene p53 in the MT-2 and Inf-3T3cells. Rigosertib was more potent than wortmannin and rapamycin in inducing sub-G1 and G2-M cell cycle arrest, as well as late apoptosis in the Inf-3T3 and MT-2 cells. It also synergized the cytotoxic effects of vincristine. These findings demonstrate that HTLV-1 downregulation of the mRNA level may occur as a negative feedback response to increased PI3K-Akt-mTOR phosphorylation by HTLV-1. Therefore, using rigosertib alone or in combination with common chemotherapy drugs may be beneficial in ATLL patients.
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Affiliation(s)
| | - Mohammad Jalili-Nik
- Department of Clinical Biochemistry, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Arash Soltani
- Department of Clinical Biochemistry, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
- Surgical Oncology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Amir R Afshari
- Department of Physiology and Pharmacology, Faculty of Medicine, North Khorasan University of Medical Sciences, Bojnurd, Iran
| | - Seyed Mahdi Hassanian
- Department of Clinical Biochemistry, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Houshang Rafatpanah
- Department of Medical Immunology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Seyed Abdolrahim Rezaee
- Department of Medical Immunology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Hamid R Sadeghnia
- Department of Pharmacology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Sajad Ataei Azimi
- Department of Hematology Oncology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Baratali Mashkani
- Bioinformatics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
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2
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Bourne CM, Wallisch P, Dacek MM, Gardner TJ, Pierre S, Vogt K, Corless BC, Bah MA, Romero-Pichardo JE, Charles A, Kurtz KG, Tan DS, Scheinberg DA. Host Interactions with Engineered T-cell Micropharmacies. Cancer Immunol Res 2023; 11:1253-1265. [PMID: 37379366 PMCID: PMC10472090 DOI: 10.1158/2326-6066.cir-22-0879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 03/08/2023] [Accepted: 06/27/2023] [Indexed: 06/30/2023]
Abstract
Genetically engineered, cytotoxic, adoptively transferred T cells localize to antigen-positive cancer cells inside patients, but tumor heterogeneity and multiple immune escape mechanisms have prevented the eradication of most solid tumor types. More effective, multifunctional engineered T cells are in development to overcome the barriers to the treatment of solid tumors, but the interactions of these highly modified cells with the host are poorly understood. We previously engineered prodrug-activating enzymatic functions into chimeric antigen receptor (CAR) T cells, endowing them with a killing mechanism orthogonal to conventional T-cell cytotoxicity. These drug-delivering cells, termed Synthetic Enzyme-Armed KillER (SEAKER) cells, demonstrated efficacy in mouse lymphoma xenograft models. However, the interactions of an immunocompromised xenograft with such complex engineered T cells are distinct from those in an immunocompetent host, precluding an understanding of how these physiologic processes may affect the therapy. Herein, we expanded the repertoire of SEAKER cells to target solid-tumor melanomas in syngeneic mouse models using specific targeting with T-cell receptor (TCR)-engineered T cells. We demonstrate that SEAKER cells localized specifically to tumors, and activated bioactive prodrugs, despite host immune responses. We additionally show that TCR-engineered SEAKER cells were efficacious in immunocompetent hosts, demonstrating that the SEAKER platform is applicable to many adoptive cell therapies.
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Affiliation(s)
- Christopher M. Bourne
- Immunology and Microbial Pathogenesis Program, Weill Cornell Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, New York
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Patrick Wallisch
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York
- Pharmacology Program, Weill Cornell Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Megan M. Dacek
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York
- Pharmacology Program, Weill Cornell Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Thomas J. Gardner
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Stephanie Pierre
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York
- Louis V. Gerstner Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Kristen Vogt
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York
- Tri-Institutional PhD Program in Chemical Biology, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Broderick C. Corless
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York
- Pharmacology Program, Weill Cornell Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Mamadou A. Bah
- Immunology and Microbial Pathogenesis Program, Weill Cornell Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Jesus E. Romero-Pichardo
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York
- Louis V. Gerstner Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Angel Charles
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Keifer G. Kurtz
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York
- Pharmacology Program, Weill Cornell Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Derek S. Tan
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York
- Louis V. Gerstner Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, New York
- Tri-Institutional PhD Program in Chemical Biology, Memorial Sloan Kettering Cancer Center, New York, New York
- Chemical Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, New York
| | - David A. Scheinberg
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, New York
- Pharmacology Program, Weill Cornell Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, New York
- Louis V. Gerstner Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, New York
- Tri-Institutional PhD Program in Chemical Biology, Memorial Sloan Kettering Cancer Center, New York, New York
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3
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Bourne CM, Wallisch P, Dacek M, Gardner T, Pierre S, Vogt K, Corless BC, Bah MA, Romero Pichardo J, Charles A, Kurtz KG, Tan DS, Scheinberg DA. Host-cell Interactions of Engineered T cell Micropharmacies. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.05.535717. [PMID: 37205431 PMCID: PMC10187158 DOI: 10.1101/2023.04.05.535717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Genetically engineered, cytotoxic, adoptive T cells localize to antigen positive cancer cells inside patients, but tumor heterogeneity and multiple immune escape mechanisms have prevented the eradication of most solid tumor types. More effective, multifunctional engineered T cells are in development to overcome the barriers to the treatment of solid tumors, but the interactions of these highly modified cells with the host are poorly understood. We previously engineered prodrug-activating enzymatic functions into chimeric antigen receptor (CAR) T cells, endowing them with an orthogonal killing mechanism to conventional T-cell cytotoxicity. These drug-delivering cells, termed Synthetic Enzyme-Armed KillER (SEAKER) cells, demonstrated efficacy in mouse lymphoma xenograft models. However, the interactions of an immunocompromised xenograft with such complex engineered T cells are distinct from those in an immunocompetent host, precluding an understanding of how these physiologic processes may affect the therapy. Here, we also expand the repertoire of SEAKER cells to target solid-tumor melanomas in syngeneic mouse models using specific targeting with TCR-engineered T cells. We demonstrate that SEAKER cells localize specifically to tumors, and activate bioactive prodrugs, despite host immune responses. We additionally show that TCR-engineered SEAKER cells are efficacious in immunocompetent hosts, demonstrating that the SEAKER platform is applicable to many adoptive cell therapies.
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Affiliation(s)
- Christopher M. Bourne
- Immunology and Microbial Pathogenesis Program, Weill Cornell Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY, USA 10065
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA 10065
| | - Patrick Wallisch
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA 10065
- Pharmacology Program, Weill Cornell Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY, USA, 10021
| | - Megan Dacek
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA 10065
- Pharmacology Program, Weill Cornell Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY, USA, 10021
| | - Thomas Gardner
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA 10065
| | - Stephanie Pierre
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA 10065
- Louis V. Gerstner Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Kristen Vogt
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA 10065
- Tri-Institutional PhD Program in Chemical Biology, Memorial Sloan Kettering Cancer Center, New York, NY, USA, 10065
| | - Broderick C. Corless
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA 10065
- Pharmacology Program, Weill Cornell Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY, USA, 10021
| | - Mamadou A. Bah
- Immunology and Microbial Pathogenesis Program, Weill Cornell Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY, USA 10065
| | - Jesus Romero Pichardo
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA 10065
- Louis V. Gerstner Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Angel Charles
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA 10065
| | - Keifer G. Kurtz
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA 10065
- Pharmacology Program, Weill Cornell Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY, USA, 10021
| | - Derek S. Tan
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA 10065
- Tri-Institutional PhD Program in Chemical Biology, Memorial Sloan Kettering Cancer Center, New York, NY, USA, 10065
- Louis V. Gerstner Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
- Chemical Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY, USA, 10065
| | - David A. Scheinberg
- Molecular Pharmacology Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA 10065
- Pharmacology Program, Weill Cornell Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY, USA, 10021
- Tri-Institutional PhD Program in Chemical Biology, Memorial Sloan Kettering Cancer Center, New York, NY, USA, 10065
- Louis V. Gerstner Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
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RNA stability regulates human T cell leukemia virus type 1 gene expression in chronically-infected CD4 T cells. Virology 2017; 508:7-17. [PMID: 28478312 DOI: 10.1016/j.virol.2017.04.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 04/25/2017] [Accepted: 04/26/2017] [Indexed: 11/22/2022]
Abstract
Regulation of expression of HTLV-1 gene products from integrated proviruses plays an important role in HTLV-1-associated disease pathogenesis. Previous studies have shown that T cell receptor (TCR)- and phorbol ester (PMA) stimulation of chronically infected CD4 T cells increases the expression of integrated HTLV-1 proviruses in latently infected cells, however the mechanism remains unknown. Analysis of HTLV-1 RNA and protein species following PMA treatment of the latently HTLV-1-infected, FS and SP T cell lines demonstrated rapid induction of tax/rex mRNA. This rapid increase in tax/rex mRNA was associated with markedly enhanced tax/rex mRNA stability while the stability of unspliced or singly spliced HTLV-1 RNAs did not increase. Tax/rex mRNA in the HTLV-1 constitutively expressing cell lines exhibited high basal stability even without PMA treatment. Our data support a model whereby T cell activation leads to increased HTLV-1 gene expression at least in part through increased tax/rex mRNA stability.
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Heat Shock Enhances the Expression of the Human T Cell Leukemia Virus Type-I (HTLV-I) Trans-Activator (Tax) Antigen in Human HTLV-I Infected Primary and Cultured T Cells. Viruses 2016; 8:v8070191. [PMID: 27409630 PMCID: PMC4974526 DOI: 10.3390/v8070191] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 06/24/2016] [Accepted: 07/01/2016] [Indexed: 12/15/2022] Open
Abstract
The environmental factors that lead to the reactivation of human T cell leukemia virus type-1 (HTLV-I) in latently infected T cells in vivo remain unknown. It has been previously shown that heat shock (HS) is a potent inducer of HTLV-I viral protein expression in long-term cultured cell lines. However, the precise HTLV-I protein(s) and mechanisms by which HS induces its effect remain ill-defined. We initiated these studies by first monitoring the levels of the trans-activator (Tax) protein induced by exposure of the HTLV-I infected cell line to HS. HS treatment at 43 °C for 30 min for 24 h led to marked increases in the level of Tax antigen expression in all HTLV-I-infected T cell lines tested including a number of HTLV-I-naturally infected T cell lines. HS also increased the expression of functional HTLV-I envelope gp46 antigen, as shown by increased syncytium formation activity. Interestingly, the enhancing effect of HS was partially inhibited by the addition of the heat shock protein 70 (HSP70)-inhibitor pifithlin-μ (PFT). In contrast, the HSP 70-inducer zerumbone (ZER) enhanced Tax expression in the absence of HS. These data suggest that HSP 70 is at least partially involved in HS-mediated stimulation of Tax expression. As expected, HS resulted in enhanced expression of the Tax-inducible host antigens, such as CD83 and OX40. Finally, we confirmed that HS enhanced the levels of Tax and gp46 antigen expression in primary human CD4⁺ T cells isolated from HTLV-I-infected humanized NOD/SCID/γc null (NOG) mice and HTLV-I carriers. In summary, the data presented herein indicate that HS is one of the environmental factors involved in the reactivation of HTLV-I in vivo via enhanced Tax expression, which may favor HTLV-I expansion in vivo.
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Miyazato P, Matsuo M, Katsuya H, Satou Y. Transcriptional and Epigenetic Regulatory Mechanisms Affecting HTLV-1 Provirus. Viruses 2016; 8:v8060171. [PMID: 27322309 PMCID: PMC4926191 DOI: 10.3390/v8060171] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 06/01/2016] [Accepted: 06/09/2016] [Indexed: 11/16/2022] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) is a retrovirus associated with human diseases, such as adult T-cell leukemia (ATL) and HTLV-1-associated myelopathy/Tropic spastic paraparesis (HAM/TSP). As a retrovirus, its life cycle includes a step where HTLV-1 is integrated into the host genomic DNA and forms proviral DNA. In the chronic phase of the infection, HTLV‑1 is known to proliferate as a provirus via the mitotic division of the infected host cells. There are generally tens of thousands of infected clones within an infected individual. They exist not only in peripheral blood, but also in various lymphoid organs. Viral proteins encoded in HTLV-1 genome play a role in the proliferation and survival of the infected cells. As is the case with other chronic viral infections, HTLV-1 gene expression induces the activation of the host immunity against the virus. Thus, the transcription from HTLV-1 provirus needs to be controlled in order to evade the host immune surveillance. There should be a dynamic and complex regulation in vivo, where an equilibrium between viral antigen expression and host immune surveillance is achieved. The mechanisms regulating viral gene expression from the provirus are a key to understanding the persistent/latent infection with HTLV-1 and its pathogenesis. In this article, we would like to review our current understanding on this topic.
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Affiliation(s)
- Paola Miyazato
- International Research Center for Medical Sciences, Center for AIDS Research, Priority Organization for Innovation and Excellence, Kumamoto University, Kumamoto 860-0811, Japan.
| | - Misaki Matsuo
- International Research Center for Medical Sciences, Center for AIDS Research, Priority Organization for Innovation and Excellence, Kumamoto University, Kumamoto 860-0811, Japan.
| | - Hiroo Katsuya
- International Research Center for Medical Sciences, Center for AIDS Research, Priority Organization for Innovation and Excellence, Kumamoto University, Kumamoto 860-0811, Japan.
| | - Yorifumi Satou
- International Research Center for Medical Sciences, Center for AIDS Research, Priority Organization for Innovation and Excellence, Kumamoto University, Kumamoto 860-0811, Japan.
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Lew QJ, Chu KL, Chia YL, Soo B, Ho JP, Ng CH, Kwok HS, Chiang CM, Chang Y, Chao SH. GCN5 inhibits XBP-1S-mediated transcription by antagonizing PCAF action. Oncotarget 2016; 6:271-87. [PMID: 25426559 PMCID: PMC4381594 DOI: 10.18632/oncotarget.2773] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 11/15/2014] [Indexed: 01/12/2023] Open
Abstract
Cellular unfolded protein response (UPR) is induced when endoplasmic reticulum (ER) is under stress. XBP-1S, the active isoform of X-box binding protein 1 (XBP-1), is a key regulator of UPR. Previously, we showed that a histone acetyltransferase (HAT), p300/CBP-associated factor (PCAF), binds to XBP-1S and functions as an activator of XBP-1S. Here, we identify general control nonderepressible 5 (GCN5), a HAT with 73% identity to PCAF, as a novel XBP-1S regulator. Both PCAF and GCN5 bind to the same domain of XBP-1S. Surprisingly, GCN5 potently blocks the XBP-1S-mediated transcription, including cellular UPR genes and latent membrane protein 1 of Epstein-Barr virus. Unlike PCAF, GCN5 acetylates XBP-1S and enhances nuclear retention and protein stability of XBP-1S. However, such GCN5-mediated acetylation of XBP-1S shows no effects on XBP-1S activity. In addition, the HAT activity of GCN5 is not required for repression of XBP-1S target genes. We further demonstrate that GCN5 inhibits XBP-1S-mediated transcription by disrupting the PCAF-XBP-1S interaction and preventing the recruitment of XBP-1S to its target genes. Taken together, our results represent the first work demonstrating that GCN5 and PCAF exhibit different functions and antagonistically regulate the XBP-1S-mediated transcription.
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Affiliation(s)
- Qiao Jing Lew
- Expression Engineering Group, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Kai Ling Chu
- Expression Engineering Group, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Yi Ling Chia
- Expression Engineering Group, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Benjamin Soo
- Expression Engineering Group, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Jia Pei Ho
- Expression Engineering Group, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Chew Har Ng
- Expression Engineering Group, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Hui Si Kwok
- Expression Engineering Group, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), Singapore
| | - Cheng-Ming Chiang
- Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Harry Hines Boulevard, Dallas, TX, USA
| | - Yao Chang
- National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Tainan, Taiwan
| | - Sheng-Hao Chao
- Expression Engineering Group, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A*STAR), Singapore. Department of Microbiology, National University of Singapore, Singapore
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HTLV-1 ORF-I Encoded Proteins and the Regulation of Host Immune Response: Viral Induced Dysregulation of Intracellular Signaling. J Immunol Res 2015; 2015:498054. [PMID: 26557721 PMCID: PMC4628651 DOI: 10.1155/2015/498054] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 08/22/2015] [Accepted: 08/31/2015] [Indexed: 01/02/2023] Open
Abstract
The human T-cell lymphotropic virus type 1 (HTLV-1) is a retrovirus associated with both proliferative and inflammatory disorders. This virus causes a persistent infection, mainly in CD4+ T lymphocyte. The ability to persist in the host is associated with the virus capacity to evade the immune response and to induce infected T-cell proliferation, once the HTLV-1 maintains the infection mainly by clonal expansion of infected cells. There are several evidences that ORF-I encoded proteins, such as p12 and p8, play an important role in this context. The present study will review the molecular mechanisms that HTLV-1 ORF-I encoded proteins have to induce dysregulation of intracellular signaling, in order to escape from immune response and to increase the infected T-cell proliferation rate. The work will also address the impact of ORF-I mutations on the human
host and perspectives in this study field.
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Mei S, Zhu H. A novel one-class SVM based negative data sampling method for reconstructing proteome-wide HTLV-human protein interaction networks. Sci Rep 2015; 5:8034. [PMID: 25620466 PMCID: PMC5379509 DOI: 10.1038/srep08034] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 12/22/2014] [Indexed: 11/09/2022] Open
Abstract
Protein-protein interaction (PPI) prediction is generally treated as a problem of binary classification wherein negative data sampling is still an open problem to be addressed. The commonly used random sampling is prone to yield less representative negative data with considerable false negatives. Meanwhile rational constraints are seldom exerted on model selection to reduce the risk of false positive predictions for most of the existing computational methods. In this work, we propose a novel negative data sampling method based on one-class SVM (support vector machine, SVM) to predict proteome-wide protein interactions between HTLV retrovirus and Homo sapiens, wherein one-class SVM is used to choose reliable and representative negative data, and two-class SVM is used to yield proteome-wide outcomes as predictive feedback for rational model selection. Computational results suggest that one-class SVM is more suited to be used as negative data sampling method than two-class PPI predictor, and the predictive feedback constrained model selection helps to yield a rational predictive model that reduces the risk of false positive predictions. Some predictions have been validated by the recent literature. Lastly, gene ontology based clustering of the predicted PPI networks is conducted to provide valuable cues for the pathogenesis of HTLV retrovirus.
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Affiliation(s)
- Suyu Mei
- 1] Software College, Shenyang Normal University, Shenyang, 110034, China [2] Bioinformatics Section, School of Biomedical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Hao Zhu
- Bioinformatics Section, School of Biomedical Sciences, Southern Medical University, Guangzhou, 510515, China
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Chia YL, Ng CH, Lashmit P, Chu KL, Lew QJ, Ho JP, Lim HL, Nissom PM, Stinski MF, Chao SH. Inhibition of human cytomegalovirus replication by overexpression of CREB1. Antiviral Res 2013; 102:11-22. [PMID: 24316029 DOI: 10.1016/j.antiviral.2013.11.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 10/28/2013] [Accepted: 11/25/2013] [Indexed: 01/01/2023]
Abstract
Expression of the human cytomegalovirus (HCMV) major immediate-early (MIE) genes is regulated by a strong enhancer-containing promoter with multiple binding sites for various transcription factors, including cyclic AMP response element binding protein 1 (CREB1). Here we show that overexpression of CREB1 potently blocked MIE transcription and HCMV replication. Surprisingly, CREB1 still exhibited strong inhibition of the MIE promoter when all five CREB binding sites within the enhancer were mutated, suggesting that CREB1 regulated the MIE gene expression indirectly. Promoter deletion analysis and site-directed mutagenesis identified the region between -130 and -50 upstream of the transcription start site of the MIE gene as the "CREB1 responsive region". Mutations of SP1/3 and NF-κB binding sites within this region interrupted the inhibitory effect induced by CREB1 overexpression. Our findings suggest that overexpression of CREB1 can cause repression of HCMV replication and may contribute to the development of new anti-HCMV strategies.
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Affiliation(s)
- Yi Ling Chia
- Expression Engineering, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A(∗)STAR), 20 Biopolis Way, #06-01 Centros, Singapore 138668, Singapore
| | - Chew Har Ng
- Expression Engineering, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A(∗)STAR), 20 Biopolis Way, #06-01 Centros, Singapore 138668, Singapore
| | - Philip Lashmit
- Department of Microbiology, University of Iowa, 51 Newton Rd., 3-772 Bowen Science Building, Iowa City, IA 52242, USA
| | - Kai Ling Chu
- Expression Engineering, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A(∗)STAR), 20 Biopolis Way, #06-01 Centros, Singapore 138668, Singapore
| | - Qiao Jing Lew
- Expression Engineering, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A(∗)STAR), 20 Biopolis Way, #06-01 Centros, Singapore 138668, Singapore
| | - Jia Pei Ho
- Expression Engineering, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A(∗)STAR), 20 Biopolis Way, #06-01 Centros, Singapore 138668, Singapore
| | - Hsueh Lee Lim
- Microarray Groups, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A(∗)STAR), 20 Biopolis Way, #06-01 Centros, Singapore 138668, Singapore
| | - Peter Morin Nissom
- Microarray Groups, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A(∗)STAR), 20 Biopolis Way, #06-01 Centros, Singapore 138668, Singapore
| | - Mark F Stinski
- Department of Microbiology, University of Iowa, 51 Newton Rd., 3-772 Bowen Science Building, Iowa City, IA 52242, USA
| | - Sheng-Hao Chao
- Expression Engineering, Bioprocessing Technology Institute, Agency for Science, Technology and Research (A(∗)STAR), 20 Biopolis Way, #06-01 Centros, Singapore 138668, Singapore; Department of Microbiology, National University of Singapore, Block MD4, 5 Science Drive 2, Singapore 117597, Singapore.
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11
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Matsuoka M, Yasunaga JI. Human T-cell leukemia virus type 1: replication, proliferation and propagation by Tax and HTLV-1 bZIP factor. Curr Opin Virol 2013; 3:684-91. [PMID: 24060211 DOI: 10.1016/j.coviro.2013.08.010] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 08/20/2013] [Accepted: 08/21/2013] [Indexed: 12/13/2022]
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) spreads primarily by cell-to-cell transmission. Therefore, HTLV-1 promotes the proliferation of infected cells to facilitate transmission. In HTLV-1 infected individuals, the provirus is present mainly in effector/memory T cells and Foxp3+ T cells. Recent study suggests that this immunophenotype is acquired by infected cells through the function of HTLV-1 bZIP factor (HBZ). Tax, which is encoded by the plus strand, is crucial for viral replication and de novo infection, while HBZ, encoded by the minus strand, is important for proliferation of infected cells. Importantly, HBZ and Tax have opposing functions in most transcription pathways. HBZ and Tax cooperate in elaborate ways to permit viral replication, proliferation of infected cells and propagation of the virus.
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Affiliation(s)
- Masao Matsuoka
- Institute for Virus Research, Kyoto University, 53 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan.
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12
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Integrase inhibitors effective against human T-cell leukemia virus type 1. Antimicrob Agents Chemother 2011; 55:2011-7. [PMID: 21343468 DOI: 10.1128/aac.01413-10] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Drugs targeting the viral enzyme integrase have been in use for several years as part of the treatment regimen for patients with human immunodeficiency virus type 1 (HIV-1), and similar classes of compounds have been shown to inhibit human T-cell leukemia virus type 1 (HTLV-1) integration in vitro. The current study shows that the clinically approved HIV-1 integrase inhibitor, raltegravir, as well as the more recent diketo acid derivative, MK-2048, are active inhibitors of HTLV-1 infection in vitro. These agents were effective in inhibiting cell-free and cell-to-cell transmission of HTLV-1 in lymphoid and nonlymphoid cells. The drugs also inhibited HTLV-1 immortalization of human peripheral blood mononuclear cells. A novel adaptation of the Alu assay for viral integration was used to show that the drugs inhibit viral integration without affecting reverse transcription. These data support the administration of raltegravir and other integrase inhibitors as treatments for patients with HTLV-1-associated diseases.
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13
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Lew QJ, Chu KL, Lee J, Koh PL, Rajasegaran V, Teo JY, Chao SH. PCAF interacts with XBP-1S and mediates XBP-1S-dependent transcription. Nucleic Acids Res 2010; 39:429-39. [PMID: 20817929 PMCID: PMC3025546 DOI: 10.1093/nar/gkq785] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
X-box binding protein 1 (XBP-1) is a key regulator required for cellular unfolded protein response (UPR) and plasma cell differentiation. In addition, involvement of XBP-1 in host cell–virus interaction and transcriptional regulation of viruses, such as human T-lymphotropic virus type 1 (HTLV-1), has been revealed recently. Two XBP-1 isoforms, XBP-1U and XBP-1S, which share an identical N-terminal domain, are present in cells. XBP-1S is a transcription activator while XBP-1U is the inactive isoform. Although the transactivation domain of XBP-1S has been identified within the XBP-1S-specific C-terminus, molecular mechanism of the transcriptional activation by XBP-1S still remains unknown. Here we report the interaction between p300/CBP-associated factor (PCAF) and XBP-1S through the C-terminal domain of XBP-1S. No binding between XBP-1U and PCAF is detected. In a cell-based reporter assay, overexpression of PCAF further stimulates the XBP-1S-mediated cellular and HTLV-1 transcription while knockdown of PCAF exhibits the opposite effect. Expression of endogenous XBP-1S cellular target genes, such as BiP and CHOP, is significantly inhibited when PCAF is knocked down. Furthermore, PCAF is recruited to the promoters of XBP-1S target genes in vivo, in a XBP-1S-dependent manner. Collectively, our results demonstrate that PCAF mediates the XBP-1S-dependent transcription through the interaction with XBP-1S.
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Affiliation(s)
- Qiao Jing Lew
- Bioprocessing Technology Institute, A*STAR (Agency for Science, Technology and Research), Singapore, Singapore
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14
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Van Prooyen N, Andresen V, Gold H, Bialuk I, Pise-Masison C, Franchini G. Hijacking the T-cell communication network by the human T-cell leukemia/lymphoma virus type 1 (HTLV-1) p12 and p8 proteins. Mol Aspects Med 2010; 31:333-43. [PMID: 20673780 DOI: 10.1016/j.mam.2010.07.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Revised: 07/22/2010] [Accepted: 07/23/2010] [Indexed: 12/14/2022]
Abstract
The non-structural proteins encoded by the orf-I, II, III, and IV genes of the human T-cell leukemia/lymphoma virus type 1 (HTLV-1) genome, are critical for the modulation of cellular gene expression and T-cell proliferation, the escape from cytotoxic T-cells and natural killer cells, and virus expression. In here, we review the main functions of the HTLV-1 orf-I products. The 12kDa product from orf-I (p12) is proteolytically cleaved within the endoplasmic reticulum (ER) to generate the 8kDa protein (p8). At the steady state, both proteins are expressed at similar levels in transfected T-cells. The p12 protein remains in the ER and cis-Golgi, whereas the p8 protein traffics to the cell surface and is recruited to the immunological synapse. The p12 and the p8 proteins have seemingly opposite effects on T-cells; the ER resident p12, modulates T-cell activation and proliferation, whereas p8 induces T-cell anergy. The p8 protein also increases the formation of cellular conduits, is transferred to neighboring T-cells, and increases virus transmission. The requirement for HTLV-1 infectivity of orf-I is demonstrated by the loss of virus infectivity in macaques exposed to an engineered virus, whereby expression of orf-I was ablated. Altogether the current knowledge demonstrates that the concerted activity of p8 and p12 is essential for the persistence of virus infected cells in the host.
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Affiliation(s)
- Nancy Van Prooyen
- Animal Models and Retroviral Vaccine Section, Vaccine Branch, National Cancer Institute, National Institute of Health, Bethesda, MD 20892-5065, USA
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15
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Abstract
Infection with the human T-cell leukemia virus-1 (HTLV-1) results in a variety of diseases including adult T-cell leukemia/lymphoma (ATL). Although the pathogenesis of these disorders is poorly understood, it involves complex interactions with the host immune system. Activation of infected T cells may play an important role in disease pathogenesis through induction of the oncogenic HTLV-1 Tax transactivator protein. To test this hypothesis, we employed transgenic mice in which Tax is regulated by the HTLV-1 LTR. T-cell receptor stimulation of LTR-Tax CD4(+) T cells induced Tax expression, hyper-proliferation, and immortalization in culture. The transition to cellular immortalization was accompanied by markedly increased expression of the antiapoptotic gene, mcl-1, previously implicated as important in T-cell survival. Immortalized cells exhibited a CD4(+)CD25(+)CD3(-) phenotype commonly observed in ATL. Engraftment of activated LTR-Tax CD4(+) T cells into NOD/Shi-scid/IL-2Rγ null mice resulted in a leukemia-like phenotype with expansion and tissue infiltration of Tax(+), CD4(+) lymphocytes. We suggest that immune activation of infected CD4(+) T cells plays an important role in the induction of Tax expression, T-cell proliferation, and pathogenesis of ATL in HTLV-1-infected individuals.
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16
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Sigalov AB. The SCHOOL of nature: III. From mechanistic understanding to novel therapies. SELF/NONSELF 2010; 1:192-224. [PMID: 21487477 PMCID: PMC3047783 DOI: 10.4161/self.1.3.12794] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Revised: 06/10/2010] [Accepted: 06/11/2010] [Indexed: 11/19/2022]
Abstract
Protein-protein interactions play a central role in biological processes and thus represent an appealing target for innovative drug design and development. They can be targeted by small molecule inhibitors, modulatory peptides and peptidomimetics, which represent a superior alternative to protein therapeutics that carry many disadvantages. Considering that transmembrane signal transduction is an attractive process to therapeutically control multiple diseases, it is fundamentally and clinically important to mechanistically understand how signal transduction occurs. Uncovering specific protein-protein interactions critical for signal transduction, a general platform for receptor-mediated signaling, the signaling chain homooligomerization (SCHOOL) platform, suggests these interactions as universal therapeutic targets. Within the platform, the general principles of signaling are similar for a variety of functionally unrelated receptors. This suggests that global therapeutic strategies targeting key protein-protein interactions involved in receptor triggering and transmembrane signal transduction may be used to treat a diverse set of diseases. This also assumes that clinical knowledge and therapeutic strategies can be transferred between seemingly disparate disorders, such as T cell-mediated skin diseases and platelet disorders or combined to develop novel pharmacological approaches. Intriguingly, human viruses use the SCHOOL-like strategies to modulate and/or escape the host immune response. These viral mechanisms are highly optimized over the millennia, and the lessons learned from viral pathogenesis can be used practically for rational drug design. Proof of the SCHOOL concept in the development of novel therapies for atopic dermatitis, rheumatoid arthritis, cancer, platelet disorders and other multiple indications with unmet needs opens new horizons in therapeutics.
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17
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Vajente N, Trevisan R, Saggioro D. HTLV-1 Tax protein cooperates with Ras in protecting cells from apoptosis. Apoptosis 2009; 14:153-63. [PMID: 19089619 DOI: 10.1007/s10495-008-0289-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Tax protein of the human T-cell leukemia virus type 1 (HTLV-1) plays a critical role in HTLV-I-correlated diseases through its ability to deregulate the expression of a vast array of cellular genes. We have previously shown that Tax counteracts apoptosis induced by stimuli triggering mitochondria apoptotic pathway, most likely by activating CREB-mediated transcription and affecting the phosphorylation levels of CREB at Ser-133. Here, we report data that indicate the oncoprotein Ras as a possible mediator of Tax-induced apoptosis protection and suggest a possible role of Tax in Ras activation. In addition, using inhibitors of down stream effectors of Ras, we found that ERK signaling is the most relevant for Tax-mediated apoptosis protection. As a whole, our findings provide intriguing evidence of a possible link between Ras signaling and Tax capability to counteract apoptosis and to enhance P-CREB levels, and implicates a potential role for Ras in HTLV-1-induced diseases.
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Affiliation(s)
- Nicola Vajente
- Department of Oncology and Surgical Sciences, Oncology Section, University of Padova, via Gattamelata 64, 35128 Padova, Italy
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18
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Ratner L, Harrington W, Feng X, Grant C, Jacobson S, Noy A, Sparano J, Lee J, Ambinder R, Campbell N, Lairmore M. Human T cell leukemia virus reactivation with progression of adult T-cell leukemia-lymphoma. PLoS One 2009; 4:e4420. [PMID: 19204798 PMCID: PMC2636875 DOI: 10.1371/journal.pone.0004420] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2008] [Accepted: 12/12/2008] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND Human T-cell leukemia virus-associated adult T-cell leukemia-lymphoma (ATLL) has a very poor prognosis, despite trials of a variety of different treatment regimens. Virus expression has been reported to be limited or absent when ATLL is diagnosed, and this has suggested that secondary genetic or epigenetic changes are important in disease pathogenesis. METHODS AND FINDINGS We prospectively investigated combination chemotherapy followed by antiretroviral therapy for this disorder. Nineteen patients were prospectively enrolled between 2002 and 2006 at five medical centers in a phase II clinical trial of infusional chemotherapy with etoposide, doxorubicin, and vincristine, daily prednisone, and bolus cyclophosphamide (EPOCH) given for two to six cycles until maximal clinical response, and followed by antiviral therapy with daily zidovudine, lamivudine, and alpha interferon-2a for up to one year. Seven patients were on study for less than one month due to progressive disease or chemotherapy toxicity. Eleven patients achieved an objective response with median duration of response of thirteen months, and two complete remissions. During chemotherapy induction, viral RNA expression increased (median 190-fold), and virus replication occurred, coincident with development of disease progression. CONCLUSIONS EPOCH chemotherapy followed by antiretroviral therapy is an active therapeutic regimen for adult T-cell leukemia-lymphoma, but viral reactivation during induction chemotherapy may contribute to treatment failure. Alternative therapies are sorely needed in this disease that simultaneously prevent virus expression, and are cytocidal for malignant cells.
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Affiliation(s)
- Lee Ratner
- Division of Oncology, Washington University School of Medicine, St Louis, Missouri, USA.
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19
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Cross talk between expression of the human T-cell leukemia virus type 1 Tax transactivator and the oncogenic bHLH transcription factor TAL1. J Virol 2008; 82:7913-22. [PMID: 18495761 DOI: 10.1128/jvi.02414-07] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The human T-cell leukemia virus type 1 (HTLV-1) Tax transactivator is known to induce or repress various cellular genes, several of them encoding transcription factors. As Tax is known to deregulate various basic bHLH factors, we looked more specifically at its effect on TAL1 (T-cell acute lymphoblastic leukemia 1), also known as SCL (stem cell leukemia). Indeed, TAL1 is deregulated in a high percentage of T-cell acute lymphoblastic leukemia cells, and its oncogenic properties are well-established. Here we show that Tax induces transcription of this proto-oncogene by stimulating the activity of the TAL1 gene promoter 1b, through both the CREB and NF-kappaB pathways. It was also observed that TAL1 upregulates HTLV-1 promoter activity, in either the presence or the absence of Tax. The viral promoter is inhibited in trans by expression of the E2A protein E47, and TAL1 is able to abrogate this inhibition. These data show the existence of a positive feedback loop between Tax and TAL1 expression and support the notion that this proto-oncogene participates in generation of adult T-cell leukemia/lymphoma by increasing the amount of the Tax oncoprotein but also possibly by its own transforming activities.
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20
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Gurumurthy M, Tan CH, Ng R, Zeiger L, Lau J, Lee J, Dey A, Philp R, Li Q, Lim TM, Price DH, Lane DP, Chao SH. Nucleophosmin interacts with HEXIM1 and regulates RNA polymerase II transcription. J Mol Biol 2008; 378:302-17. [PMID: 18371977 DOI: 10.1016/j.jmb.2008.02.055] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2007] [Revised: 02/18/2008] [Accepted: 02/25/2008] [Indexed: 11/17/2022]
Abstract
Hexamethylene bis-acetamide-inducible protein 1 (HEXIM1) was identified earlier as an inhibitor of positive transcription elongation factor b (P-TEFb), which is a key transcriptional regulator of RNA polymerase II (Pol II). Studies show that more than half of P-TEFb in cells is associated with HEXIM1, which results in the inactivation of P-TEFb. Here, we identify a nucleolar protein, nucleophosmin (NPM), as a HEXIM1-binding protein. NPM binds to HEXIM1 in vitro and in vivo, and functions as a negative regulator of HEXIM1. Over-expression of NPM leads to proteasome-mediated degradation of HEXIM1, resulting in activation of P-TEFb-dependent transcription. In contrast, an increase in HEXIM1 protein levels and a decrease in transcription are detected when NPM is knocked down. We show that a cytoplasmic mutant of NPM, NPMc+, associates with and sequesters HEXIM1 in the cytoplasm resulting in higher RNA Pol II transcription. Correspondingly, cytoplasmic localization of endogenous HEXIM1 is detected in an acute myeloid leukemia (AML) cell line containing the NPMc+ mutation, suggesting the physiological importance of HEXIM1-NPMc+ interaction. Over-expression of NPM has been detected in tumors of various histological origins and our results may provide a possible molecular mechanism for the proto-oncogenic function of NPM. Furthermore, considering that 35% of AML patients are diagnosed with NPMc+ mutation, our findings suggest that in some cases of AML, RNA Pol II transcription may be disregulated by the malfunction of NPM and the mislocation of HEXIM1.
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Affiliation(s)
- Meera Gurumurthy
- Expression Engineering Group, Bioprocessing Technology Institute, 20 Biopolis Way, #06-01 Centros, Singapore 138668, Singapore
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21
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XBP-1, a novel human T-lymphotropic virus type 1 (HTLV-1) tax binding protein, activates HTLV-1 basal and tax-activated transcription. J Virol 2008; 82:4343-53. [PMID: 18287238 DOI: 10.1128/jvi.02054-07] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
X-box binding protein 1 (XBP-1), a basic leucine zipper transcription factor, plays a key role in the cellular unfolded protein response (UPR). There are two XBP-1 isoforms in cells, spliced XBP-1S and unspliced XBP-1U. XBP-1U has been shown to bind to the 21-bp Tax-responsive element of the human T-lymphotropic virus type 1 (HTLV-1) long terminal repeat (LTR) in vitro and transactivate HTLV-1 transcription. Here we identify XBP-1S as a transcription activator of HTLV-1. Compared to XBP-1U, XBP-1S demonstrates stronger activating effects on both basal and Tax-activated HTLV-1 transcription in cells. Our results show that both XBP-1S and XBP-1U interact with Tax and bind to the HTLV-1 LTR in vivo. In addition, elevated mRNA levels of the gene for XBP-1 and several UPR genes were detected in the HTLV-1-infected C10/MJ and MT2 T-cell lines, suggesting that HTLV-1 infection may trigger the UPR in host cells. We also identify Tax as a positive regulator of the expression of the gene for XBP-1. Activation of the UPR by tunicamycin showed no effect on the HTLV-1 LTR, suggesting that HTLV-1 transcription is specifically regulated by XBP-1. Collectively, our study demonstrates a novel host-virus interaction between a cellular factor XBP-1 and transcriptional regulation of HTLV-1.
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Abstract
Protein-protein interactions play a central role in biological processes and thus are an appealing target for innovative drug design a nd development. They can be targeted bysmall molecule inhibitors, peptides and peptidomimetics, which represent an alternative to protein therapeutics that carry many disadvantages. In this chapter, I describe specific protein-protein interactions suggested by a novel model of immune signaling, the Signaling Chain HOmoOLigomerization (SCHOOL) model, to be critical for cell activation mediated by multichain immune recognition receptors (MIRRs) expressed on different cells of the hematopoietic system. Unraveling a long-standing mystery of MIRR triggering and transmembrane signaling, the SCHOOL model reveals the intrareceptor transmembrane interactions and interreceptor cytoplasmic homointeractions as universal therapeutic targets for a diverse variety of disorders mediated by immune cells. Further, assuming that the general principles underlying MIRR-mediated transmembrane signaling mechanisms are similar, the SCHOOL model can be applied to any particular receptor of the MIRR family. Thus, an important application of the SCHOOL model is that global therapeutic strategies targeting key protein-protein interactions involved in MIRR triggering and transmembrane signal transduction may be used to treat a diverse set of immune-mediated diseases. This assumes that clinical knowledge and therapeutic strategies can be transferred between seemingly disparate disorders, such as T-cell-mediated skin diseases and platelet disorders, or combined to develop novel pharmacological approaches. Intriguingly, the SCHOOL model unravels the molecular mechanisms underlying ability of different human viruses such as human immunodeficiency virus, cytomegalovirus and severe acute respiratory syndrome coronavirus to modulate and/or escape the host immune response. It also demonstrates how the lessons learned from viral pathogenesis can be used practically for rational drug design. Application of this model to platelet collagen receptor signaling has already led to the development of a novel concept of platelet inhibition and the invention of new platelet inhibitors, thus proving the suggested hypothesis and highlighting the importance and broad perspectives of the SCHOOL model in the development of new targeting strategies.
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23
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Winter HY, Dayaram T, Marriott SJ. Activation of the human T-cell leukemia virus type 1 long terminal repeat by the ternary complex factor Elk-1. J Virol 2007; 81:13075-81. [PMID: 17898074 PMCID: PMC2169132 DOI: 10.1128/jvi.00968-07] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Serum response factor (SRF) was recently shown to bind and activate the human T-cell leukemia virus type 1 (HTLV-1) promoter at bases -116 to -125 relative to the transcription start site. In addition to the SRF binding site (CArG box), serum response elements (SRE) also typically contain a binding site for a member of the ternary complex factor (TCF) family. Here we demonstrate the presence of two TCF binding sites upstream of the viral CArG box. Binding of the TCF family member Elk-1 to these sites was shown to activate transcription of the promoter. Based on these results, the position of the previously described viral SRE (vSRE) within the HTLV-1 promoter can be extended from -116 to -157 to include the two newly identified TCF sites. Purified Elk-1 bound to a probe containing the vSRE, and this complex formed a ternary complex with SRF. In addition, the complex formed by nuclear extract on this probe contained Elk-1, as shown by electrophoretic mobility shift assay supershift. Both of the predicted TCF sites independently bound Elk-1. Elk-1 activated transcription of the HTLV-1 long terminal repeat (LTR), and mutations within either of the TCF sites or the CArG box reduced responsiveness of the LTR to Elk-1. Chromatin immunoprecipitation demonstrated that Elk-1 associates with the HTLV-1 LTR in vivo. These results identify a functional SRE within the HTLV-1 LTR and suggest that both Elk-1 and SRF play important roles in regulating basal HTLV-1 gene expression.
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Affiliation(s)
- Heather Y Winter
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, MS-385, One Baylor Plaza, Houston, Texas 77030, USA
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24
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Fukumoto R, Dundr M, Nicot C, Adams A, Valeri VW, Samelson LE, Franchini G. Inhibition of T-cell receptor signal transduction and viral expression by the linker for activation of T cells-interacting p12(I) protein of human T-cell leukemia/lymphoma virus type 1. J Virol 2007; 81:9088-99. [PMID: 17582004 PMCID: PMC1951423 DOI: 10.1128/jvi.02703-06] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The p12(I) protein of human T-cell leukemia/lymphoma virus type 1 (HTLV-1) is a small oncoprotein that increases calcium release following protein kinase C activation by phorbol myristate acetate, and importantly, this effect is linker for activation of T cells (LAT) independent. Here, we demonstrate that p12(I) inhibits the phosphorylation of LAT, Vav, and phospholipase C-gamma 1 and decreases NFAT (nuclear factor of activated T cells) activation upon engagement of the T-cell receptor (TCR) with anti-CD3 antibody. Furthermore, we demonstrate that p12(I) localizes to membrane lipid rafts and, upon engagement of the TCR, relocalizes to the interface between T cells and antigen-presenting cells, defined as the immunological synapse. A p12(I) knockout molecular clone of HTLV-1 expresses more virus upon antigen stimulation than the isogenic wild type, suggesting that, by decreasing T-cell responsiveness, p12(I) curtails viral expression. Thus, p12(I) has contrasting effects on TCR signaling: it down-regulates TCR in a LAT-dependent manner on one hand, and on the other, it increases calcium release in a LAT-independent manner. The negative regulation of T-cell activation by p12(I) may have evolved to minimize immune recognition of infected CD4(+) T cells, to impair the function of infected cytotoxic CD8(+) T cells, and to favor viral persistence in the infected host.
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Affiliation(s)
- Risaku Fukumoto
- Animal Models and Retroviral Vaccines Section, National Cancer Institute, NIH, Bethesda, MD 20892-5065, USA
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25
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Schlaepfer E, Audigé A, Joller H, Speck RF. TLR7/8 Triggering Exerts Opposing Effects in Acute versus Latent HIV Infection. THE JOURNAL OF IMMUNOLOGY 2006; 176:2888-95. [PMID: 16493046 DOI: 10.4049/jimmunol.176.5.2888] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
TLRs trigger innate immunity by recognizing conserved motifs of microorganisms. Recently, ssRNAs from HIV and influenza virus were shown to trigger TLR7 and 8. Thus, we hypothesized that HIV ssRNA, by triggering TLR7/8, affects HIV pathogenesis. Indeed, HIV ssRNA rendered human lymphoid tissue of tonsillar origin or PBMC barely permissive to HIV replication. The synthetic compound R-848, which also triggers TLR7/8, showed similar anti-HIV activity. Loss of R-848's activity in lymphoid tissue depleted of B cells suggested a role for B cells in innate immunity. TLR7/8 triggering appears to exert antiviral effects through soluble factors: conditioned medium reduced HIV replication in indicator cells. Although a number of cytokines and chemokines were increased upon adding R-848 to lymphoid tissue, blocking those cytokines/chemokines (i.e., IFN-alpha receptor, IFN-gamma, MIP-1alpha, -1beta, RANTES, and stromal cell-derived factor-1) did not result in the reversal of R-848's anti-HIV activity. Thus, the nature of this soluble factor(s) remains unknown. Unlike lymphoid tissue acutely infected with HIV, triggering latently infected promonocytic cells induced the release of HIV virions. The anti-HIV effects of triggering TLR7/8 may inhibit rapid killing, while pro-HIV effects may guarantee a certain replication level. Compounds triggering TLR7/8 may be attractive drug candidates to purge latent HIV while preventing new infections.
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Affiliation(s)
- Erika Schlaepfer
- Division of Infectious Diseases and Hospital Epidemiology, Department of Internal Medicine, University Hospital of Zurich, Zurich, Switzerland
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