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Bellon M, Yeh CH, Bai XT, Nicot C. The HTLV-I oncoprotein Tax inactivates the tumor suppressor FBXW7. J Virol 2024; 98:e0040524. [PMID: 38874362 PMCID: PMC11264933 DOI: 10.1128/jvi.00405-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 05/17/2024] [Indexed: 06/15/2024] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-I) is the etiological agent of adult T-cell leukemia (ATL). Mutational analysis has demonstrated that the tumor suppressor, F-box and WD repeat domain containing 7 (FBXW7/FBW7/CDC4), is mutated in primary ATL patients. However, even in the absence of genetic mutations, FBXW7 substrates are stabilized in ATL cells, suggesting additional mechanisms can prevent FBXW7 functions. Here, we report that the viral oncoprotein Tax represses FBXW7 activity, resulting in the stabilization of activated Notch intracellular domain, c-MYC, Cyclin E, and myeloid cell leukemia sequence 1 (BCL2-related) (Mcl-1). Mechanistically, we demonstrate that Tax directly binds to FBXW7 in the nucleus, effectively outcompeting other targets for binding to FBXW7, resulting in decreased ubiquitination and degradation of FBXW7 substrates. In support of the nuclear role of Tax, a non-degradable form of the nuclear factor kappa B subunit 2 (NFκB2/p100) was found to delocalize Tax to the cytoplasm, thereby preventing Tax interactions with FBXW7 and Tax-mediated inhibition of FBXW7. Finally, we characterize a Tax mutant that is unable to interact with FBXW7, unable to block FBXW7 tumor suppressor functions, and unable to effectively transform fibroblasts. These results demonstrate that HTLV-I Tax can inhibit FBXW7 functions without genetic mutations to promote an oncogenic state. These results suggest that Tax-mediated inhibition of FBXW7 is likely critical during the early stages of the cellular transformation process. IMPORTANCE F-box and WD repeat domain containing 7 (FBXW7), a critical tumor suppressor of human cancers, is frequently mutated or epigenetically suppressed. Loss of FBXW7 functions is associated with stabilization and increased expression of oncogenic factors such as Cyclin E, c-Myc, Mcl-1, mTOR, Jun, and Notch. In this study, we demonstrate that the human retrovirus human T-cell leukemia virus type 1 oncoprotein Tax directly interacts with FBXW7, effectively outcompeting other targets for binding to FBXW7, resulting in decreased ubiquitination and degradation of FBXW7 cellular substrates. We further demonstrate that a Tax mutant unable to interact with and inactivate FBXW7 loses its ability to transform primary fibroblasts. Collectively, our results describe a novel mechanism used by a human tumor virus to promote cellular transformation.
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Affiliation(s)
- Marcia Bellon
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Chien-hung Yeh
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Xue Tao Bai
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Christophe Nicot
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, Kansas, USA
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2
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Joseph A, Cheng X, Harding J, Al-Saleem J, Green P, Veis D, Rauch D, Ratner L. Role of the CTCF Binding Site in Human T-Cell Leukemia Virus-1 Pathogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.28.596170. [PMID: 38853836 PMCID: PMC11160593 DOI: 10.1101/2024.05.28.596170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
During HTLV-1 infection, the virus integrates into the host cell genome as a provirus with a single CCCTC binding protein (CTCF) binding site (vCTCF-BS), which acts as an insulator between transcriptionally active and inactive regions. Previous studies have shown that the vCTCF-BS is important for maintenance of chromatin structure, regulation of viral expression, and DNA and histone methylation. Here, we show that the vCTCF-BS also regulates viral infection and pathogenesis in vivo in a humanized (Hu) mouse model of adult T-cell leukemia/lymphoma. Three cell lines were used to initiate infection of the Hu-mice, i) HTLV-1-WT which carries an intact HTLV-1 provirus genome, ii) HTLV-1-CTCF, which contains a provirus with a mutated vCTCF-BS which abolishes CTCF binding, and a stop codon immediate upstream of the mutated vCTCF-BS which deletes the last 23 amino acids of p12, and iii) HTLV-1-p12stop that contains the intact vCTCF-BS, but retains the same stop codon in p12 as in the HTLV-1-CTCF cell line. Hu-mice were infected with mitomycin treated or irradiated HTLV-1 producing cell lines. There was a delay in pathogenicity when Hu-mice were infected with the CTCF virus compared to mice infected with either p12 stop or WT virus. Proviral load (PVL), spleen weights, and CD4 T cell counts were significantly lower in HTLV-1-CTCF infected mice compared to HTLV-1-p12stop infected mice. Furthermore, we found a direct correlation between the PVL in peripheral blood and death of HTLV-1-CTCF infected mice. In cell lines, we found that the vCTCF-BS regulates Tax expression in a time-dependent manner. The scRNAseq analysis of splenocytes from infected mice suggests that the vCTCF-BS plays an important role in activation and expansion of T lymphocytes in vivo. Overall, these findings indicate that the vCTCF-BS regulates Tax expression, proviral load, and HTLV pathogenicity in vivo.
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Affiliation(s)
- Ancy Joseph
- Department of Medicine, Washington University School of Medicine, St Louis, MO, USA
| | - Xiaogang Cheng
- Department of Medicine, Washington University School of Medicine, St Louis, MO, USA
| | - John Harding
- Department of Medicine, Washington University School of Medicine, St Louis, MO, USA
| | - Jacob Al-Saleem
- Center for Retrovirus Research, The Ohio State University, Columbus, OH 43210
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210
| | - Patrick Green
- Center for Retrovirus Research, The Ohio State University, Columbus, OH 43210
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210
| | - Deborah Veis
- Department of Medicine, Washington University School of Medicine, St Louis, MO, USA
- Department of Pathology & Immunology, Washington University School of Medicine, St Louis, MO, USA
| | - Daniel Rauch
- Department of Medicine, Washington University School of Medicine, St Louis, MO, USA
| | - Lee Ratner
- Department of Medicine, Washington University School of Medicine, St Louis, MO, USA
- Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO, USA
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3
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Hayati RF, Nakajima R, Zhou Y, Shirasawa M, Zhao L, Fikriyanti M, Iwanaga R, Bradford AP, Kurayoshi K, Araki K, Ohtani K. Trans-Activation of the Coactivator-Associated Arginine Methyltransferase 1 ( Carm1) Gene by the Oncogene Product Tax of Human T-Cell Leukemia Virus Type 1. Genes (Basel) 2024; 15:698. [PMID: 38927636 PMCID: PMC11202806 DOI: 10.3390/genes15060698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2024] [Revised: 05/21/2024] [Accepted: 05/25/2024] [Indexed: 06/28/2024] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) is the causative agent of adult T-cell leukemia/lymphoma. The oncogene product Tax of HTLV-I is thought to play crucial roles in leukemogenesis by promoting proliferation of the virus-infected cells through activation of growth-promoting genes. These genes code for growth factors and their receptors, cytokines, cell adhesion molecules, growth signal transducers, transcription factors and cell cycle regulators. We show here that Tax activates the gene coding for coactivator-associated arginine methyltransferase 1 (CARM1), which epigenetically enhances gene expression through methylation of histones. Tax activated the Carm1 gene and increased protein expression, not only in human T-cell lines but also in normal peripheral blood lymphocytes (PHA-PBLs). Tax increased R17-methylated histone H3 on the target gene IL-2Rα, concomitant with increased expression of CARM1. Short hairpin RNA (shRNA)-mediated knockdown of CARM1 decreased Tax-mediated induction of IL-2Rα and Cyclin D2 gene expression, reduced E2F activation and inhibited cell cycle progression. Tax acted via response elements in intron 1 of the Carm1 gene, through the NF-κB pathway. These results suggest that Tax-mediated activation of the Carm1 gene contributes to leukemogenic target-gene expression and cell cycle progression, identifying the first epigenetic target gene for Tax-mediated trans-activation in cell growth promotion.
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Affiliation(s)
- Rahma F. Hayati
- Department of Biomedical Sciences, School of Biological and Environmental Sciences, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda 669-1330, Hyogo, Japan; (R.F.H.); (R.N.); (Y.Z.); (M.S.); (L.Z.); (M.F.)
| | - Rinka Nakajima
- Department of Biomedical Sciences, School of Biological and Environmental Sciences, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda 669-1330, Hyogo, Japan; (R.F.H.); (R.N.); (Y.Z.); (M.S.); (L.Z.); (M.F.)
| | - Yaxuan Zhou
- Department of Biomedical Sciences, School of Biological and Environmental Sciences, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda 669-1330, Hyogo, Japan; (R.F.H.); (R.N.); (Y.Z.); (M.S.); (L.Z.); (M.F.)
| | - Mashiro Shirasawa
- Department of Biomedical Sciences, School of Biological and Environmental Sciences, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda 669-1330, Hyogo, Japan; (R.F.H.); (R.N.); (Y.Z.); (M.S.); (L.Z.); (M.F.)
| | - Lin Zhao
- Department of Biomedical Sciences, School of Biological and Environmental Sciences, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda 669-1330, Hyogo, Japan; (R.F.H.); (R.N.); (Y.Z.); (M.S.); (L.Z.); (M.F.)
| | - Mariana Fikriyanti
- Department of Biomedical Sciences, School of Biological and Environmental Sciences, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda 669-1330, Hyogo, Japan; (R.F.H.); (R.N.); (Y.Z.); (M.S.); (L.Z.); (M.F.)
| | - Ritsuko Iwanaga
- Department of Obstetrics and Gynecology, University of Colorado School of Medicine, 12700 East 19th Avenue, Aurora, CO 80045, USA; (R.I.); (A.P.B.)
| | - Andrew P. Bradford
- Department of Obstetrics and Gynecology, University of Colorado School of Medicine, 12700 East 19th Avenue, Aurora, CO 80045, USA; (R.I.); (A.P.B.)
| | - Kenta Kurayoshi
- Division of Molecular Genetics, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Ishikawa, Japan;
| | - Keigo Araki
- Department of Morphological Biology, Ohu University School of Dentistry, 31-1 Misumido Tomitamachi, Koriyama 963-8611, Fukushima, Japan;
| | - Kiyoshi Ohtani
- Department of Biomedical Sciences, School of Biological and Environmental Sciences, Kwansei Gakuin University, 1 Gakuen Uegahara, Sanda 669-1330, Hyogo, Japan; (R.F.H.); (R.N.); (Y.Z.); (M.S.); (L.Z.); (M.F.)
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Dutta S, Ganguly A, Ghosh Roy S. An Overview of the Unfolded Protein Response (UPR) and Autophagy Pathways in Human Viral Oncogenesis. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2024; 386:81-131. [PMID: 38782502 DOI: 10.1016/bs.ircmb.2024.01.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2024]
Abstract
Autophagy and Unfolded Protein Response (UPR) can be regarded as the safe keepers of cells exposed to intense stress. Autophagy maintains cellular homeostasis, ensuring the removal of foreign particles and misfolded macromolecules from the cytoplasm and facilitating the return of the building blocks into the system. On the other hand, UPR serves as a shock response to prolonged stress, especially Endoplasmic Reticulum Stress (ERS), which also includes the accumulation of misfolded proteins in the ER. Since one of the many effects of viral infection on the host cell machinery is the hijacking of the host translational system, which leaves in its wake a plethora of misfolded proteins in the ER, it is perhaps not surprising that UPR and autophagy are common occurrences in infected cells, tissues, and patient samples. In this book chapter, we try to emphasize how UPR, and autophagy are significant in infections caused by six major oncolytic viruses-Epstein-Barr (EBV), Human Papilloma Virus (HPV), Human Immunodeficiency Virus (HIV), Human Herpesvirus-8 (HHV-8), Human T-cell Lymphotropic Virus (HTLV-1), and Hepatitis B Virus (HBV). Here, we document how whole-virus infection or overexpression of individual viral proteins in vitro and in vivo models can regulate the different branches of UPR and the various stages of macro autophagy. As is true with other viral infections, the relationship is complicated because the same virus (or the viral protein) exerts different effects on UPR and Autophagy. The nature of this response is determined by the cell types, or in some cases, the presence of diverse extracellular stimuli. The vice versa is equally valid, i.e., UPR and autophagy exhibit both anti-tumor and pro-tumor properties based on the cell type and other factors like concentrations of different metabolites. Thus, we have tried to coherently summarize the existing knowledge, the crux of which can hopefully be harnessed to design vaccines and therapies targeted at viral carcinogenesis.
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Affiliation(s)
- Shovan Dutta
- Center for Immunotherapy & Precision Immuno-Oncology (CITI), Lerner Research Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Anirban Ganguly
- Department of Biochemistry, All India Institute of Medical Sciences, Deoghar, Jharkhand, India
| | - Sounak Ghosh Roy
- Henry M Jackson for the Advancement of Military Medicine, Naval Medical Research Command, Silver Spring, MD, United States.
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5
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Nagata K, Tezuka K, Kuramitsu M, Fuchi N, Hasegawa Y, Hamaguchi I, Miura K. Establishment of a novel human T-cell leukemia virus type 1 infection model using cell-free virus. J Virol 2024; 98:e0186223. [PMID: 38294250 PMCID: PMC10878273 DOI: 10.1128/jvi.01862-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 01/04/2024] [Indexed: 02/01/2024] Open
Abstract
The primary mode of infection by human T-cell leukemia virus type 1 (HTLV-1) is cell-to-cell transmission during contact between infected cells and target cells. Cell-free HTLV-1 infections are known to be less efficient than infections with other retroviruses, and transmission of free HTLV-1 is considered not to occur in vivo. However, it has been demonstrated that cell-free HTLV-1 virions can infect primary lymphocytes and dendritic cells in vitro, and that virions embedded in biofilms on cell membranes can contribute to transmission. The establishment of an efficient cell-free HTLV-1 infection model would be a useful tool for analyzing the replication process of HTLV-1 and the clonal expansion of infected cells. We first succeeded in obtaining supernatants with high-titer cell-free HTLV-1 using a highly efficient virus-producing cell line. The HTLV-1 virions retained the structural characteristics of retroviruses. Using this cell-free infection model, we confirmed that a variety of cell lines and primary cultured cells can be infected with HTLV-1 and demonstrated that the provirus was randomly integrated into all chromosomes in the target cells. The provirus-integrated cell lines were HTLV-1-productive. Furthermore, we demonstrated for the first time that cell-free HTLV-1 is infectious in vivo using a humanized mouse model. These results indicate that this cell-free infection model recapitulates the HTLV-1 life cycle, including entry, reverse transcription, integration into the host genome, viral replication, and secondary infection. The new cell-free HTLV-1 infection model is promising as a practical resource for studying HTLV-1 infection.IMPORTANCECo-culture of infected and target cells is frequently used for studying HTLV-1 infection. Although this method efficiently infects HTLV-1, the cell mixture is complex, and it is extremely difficult to distinguish donor infected cells from target cells. In contrast, cell-free HTLV-1 infection models allow for more strict experimental conditions. In this study, we established a novel and efficient cell-free HTLV-1 infection model. Using this model, we successfully evaluated the infectivity titers of cell-free HTLV-1 as proviral loads (copies per 100 cells) in various cell lines, primary cultured cells, and a humanized mouse model. Interestingly, the HTLV-1-associated viral biofilms played an important role in enhancing the infectivity of the cell-free infection model. This cell-free HTLV-1 infection model reproduces the replication cycle of HTLV-1 and provides a simple, powerful, and alternative tool for researching HTLV-1 infection.
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Affiliation(s)
- Koh Nagata
- Department of Obstetrics and Gynecology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
- Research Center for Biological Products in the Next Generation, National Institute of Infectious Diseases, Tokyo, Japan
| | - Kenta Tezuka
- Research Center for Biological Products in the Next Generation, National Institute of Infectious Diseases, Tokyo, Japan
| | - Madoka Kuramitsu
- Research Center for Biological Products in the Next Generation, National Institute of Infectious Diseases, Tokyo, Japan
| | - Naoki Fuchi
- Department of Obstetrics and Gynecology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Yuri Hasegawa
- Department of Obstetrics and Gynecology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Isao Hamaguchi
- Research Center for Biological Products in the Next Generation, National Institute of Infectious Diseases, Tokyo, Japan
| | - Kiyonori Miura
- Department of Obstetrics and Gynecology, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
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6
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Englund DA, Jolliffe AM, Hanson GJ, Aversa Z, Zhang X, Jiang X, White TA, Zhang L, Monroe DG, Robbins PD, Niedernhofer LJ, Kamenecka TM, Khosla S, LeBrasseur NK. Senotherapeutic drug treatment ameliorates chemotherapy-induced cachexia. JCI Insight 2024; 9:e169512. [PMID: 38051584 PMCID: PMC10906225 DOI: 10.1172/jci.insight.169512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 12/01/2023] [Indexed: 12/07/2023] Open
Abstract
Cachexia is a debilitating skeletal muscle wasting condition for which we currently lack effective treatments. In the context of cancer, certain chemotherapeutics cause DNA damage and cellular senescence. Senescent cells exhibit chronic activation of the transcription factor NF-κB, a known mediator of the proinflammatory senescence-associated secretory phenotype (SASP) and skeletal muscle atrophy. Thus, targeting NF-κB represents a logical therapeutic strategy to alleviate unintended consequences of genotoxic drugs. Herein, we show that treatment with the IKK/NF-κB inhibitor SR12343 during a course of chemotherapy reduces markers of cellular senescence and the SASP in liver, skeletal muscle, and circulation and, correspondingly, attenuates features of skeletal muscle pathology. Lastly, we demonstrate that SR12343 mitigates chemotherapy-induced reductions in body weight, lean mass, fat mass, and muscle strength. These findings support senescent cells as a promising druggable target to counteract the SASP and skeletal muscle wasting in the context of chemotherapy.
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Affiliation(s)
- Davis A. Englund
- Robert and Arlene Kogod Center on Aging, and
- Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, Minnesota, USA
| | - Alyssa M. Jolliffe
- Robert and Arlene Kogod Center on Aging, and
- Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, Minnesota, USA
| | - Gabriel J. Hanson
- Robert and Arlene Kogod Center on Aging, and
- Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, Minnesota, USA
| | - Zaira Aversa
- Robert and Arlene Kogod Center on Aging, and
- Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, Minnesota, USA
| | - Xu Zhang
- Robert and Arlene Kogod Center on Aging, and
- Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, Minnesota, USA
| | - Xinyi Jiang
- Robert and Arlene Kogod Center on Aging, and
- Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, Minnesota, USA
| | - Thomas A. White
- Robert and Arlene Kogod Center on Aging, and
- Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, Minnesota, USA
| | - Lei Zhang
- Institute on the Biology of Aging and Metabolism, Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA
| | - David G. Monroe
- Robert and Arlene Kogod Center on Aging, and
- Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Paul D. Robbins
- Institute on the Biology of Aging and Metabolism, Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA
| | - Laura J. Niedernhofer
- Institute on the Biology of Aging and Metabolism, Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA
| | | | - Sundeep Khosla
- Robert and Arlene Kogod Center on Aging, and
- Division of Endocrinology, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Nathan K. LeBrasseur
- Robert and Arlene Kogod Center on Aging, and
- Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, Minnesota, USA
- Paul F. Glenn Center for the Biology of Aging at Mayo Clinic, Rochester, Minnesota, USA
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
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7
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Bellon M, Nicot C. HTLV-1 Tax Tug-of-War: Cellular Senescence and Death or Cellular Transformation. Pathogens 2024; 13:87. [PMID: 38276160 PMCID: PMC10820833 DOI: 10.3390/pathogens13010087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/11/2024] [Accepted: 01/15/2024] [Indexed: 01/27/2024] Open
Abstract
Human T cell leukemia virus type 1 (HTLV-1) is a retrovirus associated with a lymphoproliferative disease known as adult T cell leukemia/lymphoma (ATLL). HTLV-1 infection efficiently transforms human T cells in vivo and in vitro. The virus does not transduce a proto-oncogene, nor does it integrate into tumor-promoting genomic sites. Instead, HTLV-1 uses a random mutagenesis model, resulting in cellular transformation. Expression of the viral protein Tax is critical for the immortalization of infected cells by targeting specific cellular signaling pathways. However, Tax is highly immunogenic and represents the main target for the elimination of virally infected cells by host cytotoxic T cells (CTLs). In addition, Tax expression in naïve cells induces pro-apoptotic signals and has been associated with the induction of non-replicative cellular senescence. This review will explore these conundrums and discuss the mechanisms used by the Tax viral oncoprotein to influence life-and-death cellular decisions and affect HTLV-1 pathogenesis.
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Affiliation(s)
| | - Christophe Nicot
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, 3901 Rainbow Blvd, Kansas City, KS 66160, USA;
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Marino-Merlo F, Grelli S, Mastino A, Lai M, Ferrari P, Nicolini A, Pistello M, Macchi B. Human T-Cell Leukemia Virus Type 1 Oncogenesis between Active Expression and Latency: A Possible Source for the Development of Therapeutic Targets. Int J Mol Sci 2023; 24:14807. [PMID: 37834255 PMCID: PMC10572738 DOI: 10.3390/ijms241914807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Revised: 09/16/2023] [Accepted: 09/28/2023] [Indexed: 10/15/2023] Open
Abstract
The human T-cell leukemia virus type 1 (HTLV-1) is the only known human oncogenic retrovirus. HTLV-1 can cause a type of cancer called adult T-cell leukemia/lymphoma (ATL). The virus is transmitted through the body fluids of infected individuals, primarily breast milk, blood, and semen. At least 5-10 million people in the world are infected with HTLV-1. In addition to ATL, HTLV-1 infection can also cause HTLV-I-associated myelopathy (HAM/TSP). ATL is characterized by a low viral expression and poor prognosis. The oncogenic mechanism triggered by HTLV-1 is extremely complex and the molecular pathways are not fully understood. However, viral regulatory proteins Tax and HTLV-1 bZIP factor (HBZ) have been shown to play key roles in the transformation of HTLV-1-infected T cells. Moreover, several studies have shown that the final fate of HTLV-1-infected transformed Tcell clones is the result of a complex interplay of HTLV-1 oncogenic protein expression with cellular transcription factors that subvert the cell cycle and disrupt regulated cell death, thereby exerting their transforming effects. This review provides updated information on the mechanisms underlying the transforming action of HTLV-1 and highlights potential therapeutic targets to combat ATL.
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Affiliation(s)
- Francesca Marino-Merlo
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, 98166 Messina, Italy;
| | - Sandro Grelli
- Department of Experimental Medicine, University of Rome “Tor Vergata”, 00133 Rome, Italy;
| | - Antonio Mastino
- The Institute of Translational Pharmacology, CNR, 00133 Rome, Italy;
| | - Michele Lai
- Retrovirus Center and Virology Section, Department of Translational Research, University of Pisa, 56100 Pisa, Italy; (M.L.); (M.P.)
| | - Paola Ferrari
- Unit of Oncology, Department of Medical and Oncological Area, Azienda Ospedaliera—Universitaria Pisana, 56125 Pisa, Italy;
| | - Andrea Nicolini
- Department of Oncology, Transplantations and New Technologies in Medicine, University of Pisa, 56126 Pisa, Italy
| | - Mauro Pistello
- Retrovirus Center and Virology Section, Department of Translational Research, University of Pisa, 56100 Pisa, Italy; (M.L.); (M.P.)
| | - Beatrice Macchi
- Department of Chemical Science and Technology, University of Rome “Tor Vergata”, 00133 Rome, Italy;
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9
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Smith S, Seth J, Midkiff A, Stahl R, Syu YC, Shkriabai N, Kvaratskhelia M, Musier-Forsyth K, Jain P, Green PL, Panfil AR. The Pleiotropic Effects of YBX1 on HTLV-1 Transcription. Int J Mol Sci 2023; 24:13119. [PMID: 37685922 PMCID: PMC10487795 DOI: 10.3390/ijms241713119] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 08/18/2023] [Accepted: 08/21/2023] [Indexed: 09/10/2023] Open
Abstract
HTLV-1 is an oncogenic human retrovirus and the etiologic agent of the highly aggressive ATL malignancy. Two viral genes, Tax and Hbz, are individually linked to oncogenic transformation and play an important role in the pathogenic process. Consequently, regulation of HTLV-1 gene expression is a central feature in the viral lifecycle and directly contributes to its pathogenic potential. Herein, we identified the cellular transcription factor YBX1 as a binding partner for HBZ. We found YBX1 activated transcription and enhanced Tax-mediated transcription from the viral 5' LTR promoter. Interestingly, YBX1 also interacted with Tax. shRNA-mediated loss of YBX1 decreased transcript and protein abundance of both Tax and HBZ in HTLV-1-transformed T-cell lines, as well as Tax association with the 5' LTR. Conversely, YBX1 transcriptional activation of the 5' LTR promoter was increased in the absence of HBZ. YBX1 was found to be associated with both the 5' and 3' LTRs in HTLV-1-transformed and ATL-derived T-cell lines. Together, these data suggest that YBX1 positively influences transcription from both the 5' and 3' promoter elements. YBX1 is able to interact with Tax and help recruit Tax to the 5' LTR. However, through interactions with HBZ, YBX1 transcriptional activation of the 5' LTR is repressed.
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Affiliation(s)
- Susan Smith
- Center for Retrovirus Research, Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA; (S.S.); (J.S.); (A.M.)
| | - Jaideep Seth
- Center for Retrovirus Research, Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA; (S.S.); (J.S.); (A.M.)
| | - Amanda Midkiff
- Center for Retrovirus Research, Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA; (S.S.); (J.S.); (A.M.)
| | - Rachel Stahl
- Center for Retrovirus Research, Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA; (S.S.); (J.S.); (A.M.)
| | - Yu-Ci Syu
- Center for Retrovirus Research, Department of Chemistry and Biochemistry, Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA; (Y.-C.S.); (K.M.-F.)
| | - Nikoloz Shkriabai
- Division of Infectious Diseases, Anschutz Medical Campus, University of Colorado School of Medicine, Aurora, CO 80045, USA; (N.S.); (M.K.)
| | - Mamuka Kvaratskhelia
- Division of Infectious Diseases, Anschutz Medical Campus, University of Colorado School of Medicine, Aurora, CO 80045, USA; (N.S.); (M.K.)
| | - Karin Musier-Forsyth
- Center for Retrovirus Research, Department of Chemistry and Biochemistry, Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA; (Y.-C.S.); (K.M.-F.)
| | - Pooja Jain
- Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, PA 19129, USA;
| | - Patrick L. Green
- Center for Retrovirus Research, Comprehensive Cancer Center and Solove Research Institute, Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA;
| | - Amanda R. Panfil
- Center for Retrovirus Research, Comprehensive Cancer Center and Solove Research Institute, Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA;
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10
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Mohanty S, Harhaj EW. Mechanisms of Innate Immune Sensing of HTLV-1 and Viral Immune Evasion. Pathogens 2023; 12:pathogens12050735. [PMID: 37242405 DOI: 10.3390/pathogens12050735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 05/15/2023] [Accepted: 05/18/2023] [Indexed: 05/28/2023] Open
Abstract
Human T lymphotropic virus-1 (HTLV-1) was the first identified oncoretrovirus, which infects and establishes a persistent infection in approximately 10-20 million people worldwide. Although only ~5% of infected individuals develop pathologies such as adult T-cell leukemia/lymphoma (ATLL) or a neuroinflammatory disorder termed HTLV-1-asssociated myelopathy/tropical spastic paraparesis (HAM/TSP), asymptomatic carriers are more susceptible to opportunistic infections. Furthermore, ATLL patients are severely immunosuppressed and prone to other malignancies and other infections. The HTLV-1 replication cycle provides ligands, mainly nucleic acids (RNA, RNA/DNA intermediates, ssDNA intermediates, and dsDNA), that are sensed by different pattern recognition receptors (PRRs) to trigger immune responses. However, the mechanisms of innate immune detection and immune responses to HTLV-1 infection are not well understood. In this review, we highlight the functional roles of different immune sensors in recognizing HTLV-1 infection in multiple cell types and the antiviral roles of host restriction factors in limiting persistent infection of HTLV-1. We also provide a comprehensive overview of intricate strategies employed by HTLV-1 to subvert the host innate immune response that may contribute to the development of HTLV-1-associated diseases. A more detailed understanding of HTLV-1-host pathogen interactions may inform novel strategies for HTLV-1 antivirals, vaccines, and treatments for ATLL or HAM/TSP.
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Affiliation(s)
- Suchitra Mohanty
- Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, PA 17033, USA
| | - Edward W Harhaj
- Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, PA 17033, USA
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11
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Romerio F. Origin and functional role of antisense transcription in endogenous and exogenous retroviruses. Retrovirology 2023; 20:6. [PMID: 37194028 DOI: 10.1186/s12977-023-00622-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 04/30/2023] [Indexed: 05/18/2023] Open
Abstract
Most proteins expressed by endogenous and exogenous retroviruses are encoded in the sense (positive) strand of the genome and are under the control of regulatory elements within the 5' long terminal repeat (LTR). A number of retroviral genomes also encode genes in the antisense (negative) strand and their expression is under the control of negative sense promoters within the 3' LTR. In the case of the Human T-cell Lymphotropic Virus 1 (HTLV-1), the antisense protein HBZ has been shown to play a critical role in the virus lifecycle and in the pathogenic process, while the function of the Human Immunodeficiency Virus 1 (HIV-1) antisense protein ASP remains unknown. However, the expression of 3' LTR-driven antisense transcripts is not always demonstrably associated with the presence of an antisense open reading frame encoding a viral protein. Moreover, even in the case of retroviruses that do express an antisense protein, such as HTLV-1 and the pandemic strains of HIV-1, the 3' LTR-driven antisense transcript shows both protein-coding and noncoding activities. Indeed, the ability to express antisense transcripts appears to be phylogenetically more widespread among endogenous and exogenous retroviruses than the presence of a functional antisense open reading frame within these transcripts. This suggests that retroviral antisense transcripts may have originated as noncoding molecules with regulatory activity that in some cases later acquired protein-coding function. Here, we will review examples of endogenous and exogenous retroviral antisense transcripts, and the ways through which they benefit viral persistence in the host.
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Affiliation(s)
- Fabio Romerio
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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12
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Bangham CRM. HTLV-1 persistence and the oncogenesis of adult T-cell leukemia/lymphoma. Blood 2023; 141:2299-2306. [PMID: 36800643 PMCID: PMC10646791 DOI: 10.1182/blood.2022019332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 02/05/2023] [Accepted: 02/08/2023] [Indexed: 02/19/2023] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-1), also known as human T-lymphotropic virus type 1, causes the aggressive malignancy known as adult T-cell leukemia/lymphoma (ATL) in 5% of infected people and a chronic progressive inflammatory disease of the central nervous system, HTLV-1-associated myelopathy, in ∼0.3% to 4% of them, varying between regions where it is endemic. Reliable treatments are lacking for both conditions, although there have been promising recent advances in the prevention and treatment of ATL. Because ATL typically develops after several decades of infection, it is necessary to understand how the virus persists in the host despite a strong immune response, and how this persistence results in oncogenesis.
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13
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Hleihel R, Skayneh H, de Thé H, Hermine O, Bazarbachi A. Primary cells from patients with adult T cell leukemia/lymphoma depend on HTLV-1 Tax expression for NF-κB activation and survival. Blood Cancer J 2023; 13:67. [PMID: 37137914 PMCID: PMC10156663 DOI: 10.1038/s41408-023-00841-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/13/2023] [Accepted: 04/19/2023] [Indexed: 05/05/2023] Open
Abstract
Adult T cell leukemia/lymphoma (ATL) is an aggressive malignancy secondary to chronic infection with human T cell leukemia virus type 1 (HTLV-1). The viral oncoprotein Tax initiates T cell transformation through activation of critical cellular pathways, including NF-κB. Unexpectedly, Tax protein is not detectable in most ATL cells, in contrast to the HTLV-1 HBZ protein which antagonizes Tax effects. Here, we demonstrate that primary ATL cells from patients with acute or chronic ATL express very low levels of Tax mRNA and protein. Critically, survival of these primary ATL cells is dependent on continued Tax expression. Mechanistically, Tax extinction results in reversal of NF-κB activation, P53/PML activation and apoptosis. Tax drives interleukin-10 (IL-10) expression and recombinant IL-10 rescues the survival of tax-depleted primary ATL cells. These results demonstrate the critical role of continued Tax and IL-10 expression for the survival of primary ATL cells, highlighting their relevance as therapeutic targets.
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Affiliation(s)
- Rita Hleihel
- Department of Internal Medicine, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Hala Skayneh
- Department of Internal Medicine, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Hugues de Thé
- INSERM UMR 944, CNRS UMR 7212, Institut Universitaire d'Hématologie, Université Paris-Cité, Hôpital St. Louis 1, Paris, France
- Service d'Hématologie, Assistance Publique, Hôpital St. Louis 1, Paris, France
- College de France, PSL research University, Paris, France
| | - Olivier Hermine
- Institut Imagine-INSERM U1163, Necker Hospital, University of Paris, Paris, France
- Department of Hematology, Necker Hospital, University of Paris, Assistance Publique Hôpitaux de Paris, Paris, France
| | - Ali Bazarbachi
- Department of Internal Medicine, Faculty of Medicine, American University of Beirut, Beirut, Lebanon.
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon.
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14
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Ma X, Han S, Liu Y, Chen Y, Li P, Liu X, Chang L, Chen YA, Chen F, Hou Q, Hou L. DAPL1 prevents epithelial-mesenchymal transition in the retinal pigment epithelium and experimental proliferative vitreoretinopathy. Cell Death Dis 2023; 14:158. [PMID: 36841807 PMCID: PMC9968328 DOI: 10.1038/s41419-023-05693-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 02/14/2023] [Accepted: 02/16/2023] [Indexed: 02/27/2023]
Abstract
Epithelial-mesenchymal transition (EMT) of the retinal pigment epithelium (RPE) is a hallmark of the pathogenesis of proliferative vitreoretinopathy (PVR) that can lead to severe vision loss. Nevertheless, the precise regulatory mechanisms underlying the pathogenesis of PVR remain largely unknown. Here, we show that the expression of death-associated protein-like 1 (DAPL1) is downregulated in PVR membranes and that DAPL1 deficiency promotes EMT in RPE cells in mice. In fact, adeno-associated virus (AAV)-mediated DAPL1 overexpression in RPE cells of Dapl1-deficient mice inhibited EMT in physiological and retinal-detachment states. In a rabbit model of PVR, ARPE-19 cells overexpressing DAPL1 showed reduced ability to induce experimental PVR, and AAV-mediated DAPL1 delivery attenuated the severity of experimental PVR. Furthermore, a mechanistic study revealed that DAPL1 promotes P21 phosphorylation and its stabilization partially through NFκB (RelA) in RPE cells, whereas the knockdown of P21 led to neutralizing effects on DAPL1-dependent EMT inhibition and enhanced the severity of experimental PVR. These results suggest that DAPL1 acts as a novel suppressor of RPE-EMT and has an important role in antagonizing the pathogenesis of experimental PVR. Hence, this finding has implications for understanding the mechanism of and potential therapeutic applications for PVR.
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Affiliation(s)
- Xiaoyin Ma
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, 325003, China. .,State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, 325003, China.
| | - Shuxian Han
- grid.268099.c0000 0001 0348 3990Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, 325003 China ,grid.412679.f0000 0004 1771 3402Department of Ophthalmology, First Affiliated Hospital of Anhui Medical University, Hefei, 230022 China
| | - Youjia Liu
- grid.268099.c0000 0001 0348 3990Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, 325003 China
| | - Yu Chen
- grid.268099.c0000 0001 0348 3990Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, 325003 China ,grid.268099.c0000 0001 0348 3990State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, 325003 China
| | - Pingping Li
- grid.268099.c0000 0001 0348 3990Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, 325003 China
| | - Xiaoyan Liu
- grid.268099.c0000 0001 0348 3990Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, 325003 China
| | - Lifu Chang
- grid.268099.c0000 0001 0348 3990Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, 325003 China
| | - Ying-ao Chen
- grid.268099.c0000 0001 0348 3990Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, 325003 China
| | - Feng Chen
- grid.268099.c0000 0001 0348 3990School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, 325003 China
| | - Qiang Hou
- grid.268099.c0000 0001 0348 3990State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, 325003 China
| | - Ling Hou
- Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, 325003, China. .,State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, 325003, China.
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15
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Wu L, Brzostek J, Sakthi Vale PD, Wei Q, Koh CKT, Ong JXH, Wu LZ, Tan JC, Chua YL, Yap J, Song Y, Tan VJY, Tan TYY, Lai J, MacAry PA, Gascoigne NRJ. CD28-CAR-T cell activation through FYN kinase signaling rather than LCK enhances therapeutic performance. Cell Rep Med 2023; 4:100917. [PMID: 36696897 PMCID: PMC9975250 DOI: 10.1016/j.xcrm.2023.100917] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Revised: 09/07/2022] [Accepted: 01/04/2023] [Indexed: 01/26/2023]
Abstract
Signal transduction induced by chimeric antigen receptors (CARs) is generally believed to rely on the activity of the SRC family kinase (SFK) LCK, as is the case with T cell receptor (TCR) signaling. Here, we show that CAR signaling occurs in the absence of LCK. This LCK-independent signaling requires the related SFK FYN and a CD28 intracellular domain within the CAR. LCK-deficient CAR-T cells are strongly signaled through CAR and have better in vivo efficacy with reduced exhaustion phenotype and enhanced induction of memory and proliferation. These distinctions can be attributed to the fact that FYN signaling tends to promote proliferation and survival, whereas LCK signaling promotes strong signaling that tends to lead to exhaustion. This non-canonical signaling of CAR-T cells provides insight into the initiation of both TCR and CAR signaling and has important clinical implications for improvement of CAR function.
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Affiliation(s)
- Ling Wu
- Immunology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore; Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore
| | - Joanna Brzostek
- Immunology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore; Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore
| | - Previtha Dawn Sakthi Vale
- Immunology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore; Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore
| | - Qianru Wei
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore
| | - Clara K T Koh
- Immunology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore; Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore
| | - June Xu Hui Ong
- Immunology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore; Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore
| | - Liang-Zhe Wu
- Immunology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore; Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore
| | - Jia Chi Tan
- Immunology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore; Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore
| | - Yen Leong Chua
- Immunology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore; Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore
| | - Jiawei Yap
- Immunology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore; Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore
| | - Yuan Song
- Immunology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore; Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore; Immunology Programme, Life Sciences Institute, National University of Singapore, Singapore, Singapore
| | - Vivian Jia Yi Tan
- Immunology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore; Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore
| | - Triscilla Y Y Tan
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore
| | - Junyun Lai
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore; Immunology Programme, Life Sciences Institute, National University of Singapore, Singapore, Singapore
| | - Paul A MacAry
- Immunology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore; Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore; Immunology Programme, Life Sciences Institute, National University of Singapore, Singapore, Singapore; Cancer Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Nicholas R J Gascoigne
- Immunology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore; Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5 Science Drive 2, Singapore 117545, Singapore; Cancer Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
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16
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Ramanayake S, Moulding DA, Tanaka Y, Singh A, Bangham CRM. Dynamics and consequences of the HTLV-1 proviral plus-strand burst. PLoS Pathog 2022; 18:e1010774. [PMID: 36441826 PMCID: PMC9731428 DOI: 10.1371/journal.ppat.1010774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 12/08/2022] [Accepted: 11/15/2022] [Indexed: 11/30/2022] Open
Abstract
Expression of the transcriptional transactivator protein Tax, encoded on the proviral plus-strand of human T-cell leukaemia virus type 1 (HTLV-1), is crucial for the replication of the virus, but Tax-expressing cells are rarely detected in fresh blood ex vivo. The dynamics and consequences of the proviral plus-strand transcriptional burst remain insufficiently characterised. We combined time-lapse live-cell imaging, single-cell tracking and mathematical modelling to study the dynamics of Tax expression at single-cell resolution in two naturally-infected, non-malignant T-cell clones transduced with a short-lived enhanced green fluorescent protein (d2EGFP) Tax reporter system. Five different patterns of Tax expression were observed during the 30-hour observation period; the distribution of these patterns differed between the two clones. The mean duration of Tax expression in the two clones was 94 and 417 hours respectively, estimated from mathematical modelling of the experimental data. Tax expression was associated with a transient slowing in cell-cycle progression and proliferation, increased apoptosis, and enhanced activation of the DNA damage response pathways. Longer-term follow-up (14 days) revealed an increase in the proportion of proliferating cells and a decrease in the fraction of apoptotic cells as the cells ceased Tax expression, resulting in a greater net expansion of the initially Tax-positive population. Time-lapse live-cell imaging showed enhanced cell-to-cell adhesion among Tax-expressing cells, and decreased cell motility of Tax-expressing cells at the single-cell level. The results demonstrate the within-clone and between-clone heterogeneity in the dynamics and patterns of HTLV-1 plus-strand transcriptional bursts and the balance of positive and negative consequences of the burst for the host cell.
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Affiliation(s)
- Saumya Ramanayake
- Department of Infectious Diseases, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Dale A. Moulding
- Light Microscopy Core Facility, Great Ormond Street Institute of Child Health, University College London, London, United Kingdom
| | - Yuetsu Tanaka
- Department of Infectious Disease and Immunology, Okinawa-Asia Research Center of Medical Science, Faculty of Medicine, University of the Ryukyus, Nishihara, Okinawa, Japan
| | - Abhyudai Singh
- Department of Electrical and Computer Engineering, University of Delaware, Newark, Delaware, United States of America
| | - Charles R. M. Bangham
- Department of Infectious Diseases, Faculty of Medicine, Imperial College London, London, United Kingdom
- * E-mail:
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17
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El Hajj H, Bazarbachi A. Interplay between innate immunity and the viral oncoproteins Tax and HBZ in the pathogenesis and therapeutic response of HTLV-1 associated adult T cell leukemia. Front Immunol 2022; 13:957535. [PMID: 35935975 PMCID: PMC9352851 DOI: 10.3389/fimmu.2022.957535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 06/27/2022] [Indexed: 11/24/2022] Open
Abstract
The Human T-cell Leukemia virus type 1 (HTLV-1) causes an array of pathologies, the most aggressive of which is adult T-cell leukemia (ATL), a fatal blood malignancy with dismal prognosis. The progression of these diseases is partly ascribed to the failure of the immune system in controlling the spread of virally infected cells. HTLV-1 infected subjects, whether asymptomatic carriers or symptomatic patients are prone to opportunistic infections. An increasing body of literature emphasizes the interplay between HTLV-1, its associated pathologies, and the pivotal role of the host innate and adoptive immune system, in shaping the progression of HTLV-1 associated diseases and their response to therapy. In this review, we will describe the modalities adopted by the malignant ATL cells to subvert the host innate immune response with emphasis on the role of the two viral oncoproteins Tax and HBZ in this process. We will also provide a comprehensive overview on the function of innate immunity in the therapeutic response to chemotherapy, anti-viral or targeted therapies in the pre-clinical and clinical settings.
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Affiliation(s)
- Hiba El Hajj
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Ali Bazarbachi
- Department of Internal Medicine, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
- *Correspondence: Ali Bazarbachi,
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18
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Kiik H, Ramanayake S, Miura M, Tanaka Y, Melamed A, Bangham CRM. Time-course of host cell transcription during the HTLV-1 transcriptional burst. PLoS Pathog 2022; 18:e1010387. [PMID: 35576236 PMCID: PMC9135347 DOI: 10.1371/journal.ppat.1010387] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 05/26/2022] [Accepted: 04/22/2022] [Indexed: 12/30/2022] Open
Abstract
The human T-cell leukemia virus type 1 (HTLV-1) transactivator protein Tax has pleiotropic functions in the host cell affecting cell-cycle regulation, DNA damage response pathways and apoptosis. These actions of Tax have been implicated in the persistence and pathogenesis of HTLV-1-infected cells. It is now known that tax expression occurs in transcriptional bursts of the proviral plus-strand, but the effects of the burst on host transcription are not fully understood. We carried out RNA sequencing of two naturally-infected T-cell clones transduced with a Tax-responsive Timer protein, which undergoes a time-dependent shift in fluorescence emission, to study transcriptional changes during successive phases of the HTLV-1 plus-strand burst. We found that the transcriptional regulation of genes involved in the NF-κB pathway, cell-cycle regulation, DNA damage response and apoptosis inhibition were immediate effects accompanying the plus-strand burst, and are limited to the duration of the burst. The results distinguish between the immediate and delayed effects of HTLV-1 reactivation on host transcription, and between clone-specific effects and those observed in both clones. The major transcriptional changes in the infected host T-cells observed here, including NF-κB, are transient, suggesting that these pathways are not persistently activated at high levels in HTLV-1-infected cells. The two clones diverged strongly in their expression of genes regulating the cell cycle. Up-regulation of senescence markers was a delayed effect of the proviral plus-strand burst and the up-regulation of some pro-apoptotic genes outlasted the burst. We found that activation of the aryl hydrocarbon receptor (AhR) pathway enhanced and prolonged the proviral burst, but did not increase the rate of reactivation. Our results also suggest that sustained plus-strand expression is detrimental to the survival of infected cells.
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Affiliation(s)
- Helen Kiik
- Department of Infectious Diseases, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Saumya Ramanayake
- Department of Infectious Diseases, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Michi Miura
- Department of Infectious Diseases, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Yuetsu Tanaka
- Department of Infectious Disease and Immunology, Okinawa-Asia Research Center of Medical Science, Faculty of Medicine, University of the Ryukyus, Nishihara, Okinawa, Japan
| | - Anat Melamed
- Department of Infectious Diseases, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Charles R. M. Bangham
- Department of Infectious Diseases, Faculty of Medicine, Imperial College London, London, United Kingdom
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19
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NF-κB-Induced R-Loops and Genomic Instability in HTLV-1-Infected and Adult T-Cell Leukemia Cells. Viruses 2022; 14:v14050877. [PMID: 35632619 PMCID: PMC9147355 DOI: 10.3390/v14050877] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 04/20/2022] [Accepted: 04/21/2022] [Indexed: 02/04/2023] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) is a human delta retrovirus that causes adult T-cell leukemia/lymphoma (ATL) in 3–5% of the infected population after decades of clinical latency. HTLV-1 Tax is a potent activator of IKK/NF-κB and a clastogen. While NF-κB activities are associated with cell survival and proliferation, constitutive NF-κB activation (NF-κB hyperactivation) by Tax leads to senescence and oncogenesis. Until recently, the mechanisms underlying the DNA damage and senescence induced by Tax and NF-κB were unknown. Current data indicate that NF-κB hyperactivation by Tax causes the accumulation of a nucleic acid structure known as an R-loop. R-loop excision by the transcription-coupled nucleotide excision repair (TC-NER) endonucleases, Xeroderma pigmentosum F (XPF), and XPG, in turn, promotes DNA double-strand breaks (DSBs). NF-κB blockade prevents Tax-induced R-loop accumulation, DNA damage, and senescence. In the same vein, the silencing of XPF and XPG mitigates Tax senescence, while deficiency in either or both frequently occurs in ATL of all types. ATL cells maintain constitutively active NF-κB, accumulate R-loops, and resist Tax-induced senescence. These results suggest that ATL cells must have acquired adaptive changes to prevent senescence and benefit from the survival and proliferation advantages conferred by Tax and NF-κB. In this review, the roles of R-loops in Tax- and NF-κB-induced DNA DSBs, senescence, and ATL development, and the epigenetic and genetic alterations that arise in ATL to reduce R-loop-associated DNA damage and avert senescence will be discussed.
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Abstract
The Hippo pathway plays critical roles in controlling cell proliferation, and its dysregulation is widely implicated in numerous human cancers. YAP, a Hippo signaling effector, often acts as a nexus and integrator for multiple prominent signaling networks. In this study, we discover NF-κB cross talk with the Hippo pathway and identify p65 as a critical regulator for YAP nuclear retention and transcriptional activity. Furthermore, we find that p65-induced YAP activation is essential for maintaining the proliferation of ATL cells in vitro and in vivo. Our findings unravel the functional interplay between NF-κB and YAP signaling and provide mechanistic insights into the YAP-dependent growth control pathway and tumorigenesis. Adult T-cell leukemia/lymphoma (ATL) is an aggressive malignancy caused by human T-cell leukemia virus type 1 (HTLV-1) infection. HTLV-1 exerts its oncogenic functions by interacting with signaling pathways involved in cell proliferation and transformation. Dysregulation of the Hippo/YAP pathway is associated with multiple cancers, including virus-induced malignancies. In the present study, we observe that expression of YAP, which is the key effector of Hippo signaling, is elevated in ATL cells by the action of the HTLV-1 Tax protein. YAP transcriptional activity is remarkably enhanced in HTLV-1–infected cells and ATL patients. In addition, Tax activates the YAP protein via a mechanism involving the NF-κB/p65 pathway. As a mechanism for this cross talk between the Hippo and NF-κB pathways, we found that p65 abrogates the interaction between YAP and LATS1, leading to suppression of YAP phosphorylation, inhibition of ubiquitination-dependent degradation of YAP, and YAP nuclear accumulation. Finally, knockdown of YAP suppresses the proliferation of ATL cells in vitro and tumor formation in ATL-engrafted mice. Taken together, our results suggest that p65-induced YAP activation is essential for ATL pathogenesis and implicate YAP as a potential therapeutic target for ATL treatment.
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Zhang L, Zhao J, Mu X, McGowan SJ, Angelini L, O'Kelly RD, Yousefzadeh MJ, Sakamoto A, Aversa Z, LeBrasseur NK, Suh Y, Huard J, Kamenecka TM, Niedernhofer LJ, Robbins PD. Novel small molecule inhibition of IKK/NF-κB activation reduces markers of senescence and improves healthspan in mouse models of aging. Aging Cell 2021; 20:e13486. [PMID: 34734460 PMCID: PMC8672781 DOI: 10.1111/acel.13486] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 09/01/2021] [Accepted: 09/13/2021] [Indexed: 11/30/2022] Open
Abstract
Constitutive NF-κB activation is associated with cellular senescence and stem cell dysfunction and rare variants in NF-κB family members are enriched in centenarians. We recently identified a novel small molecule (SR12343) that inhibits IKK/NF-κB activation by disrupting the association between IKKβ and NEMO. Here we investigated the therapeutic effects of SR12343 on senescence and aging in three different mouse models. SR12343 reduced senescence-associated beta-galactosidase (SA-β-gal) activity in oxidative stress-induced senescent mouse embryonic fibroblasts as well as in etoposide-induced senescent human IMR90 cells. Chronic administration of SR12343 to the Ercc1-/∆ and Zmpste24-/- mouse models of accelerated aging reduced markers of cellular senescence and SASP and improved multiple parameters of aging. SR12343 also reduced markers of senescence and increased muscle fiber size in 2-year-old WT mice. Taken together, these results demonstrate that IKK/NF-κB signaling pathway represents a promising target for reducing markers of cellular senescence, extending healthspan and treating age-related diseases.
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Affiliation(s)
- Lei Zhang
- Department of Biochemistry, Molecular Biology and BiophysicsInstitute on the Biology of Aging and MetabolismUniversity of MinnesotaMinneapolisMinnesotaUSA
| | - Jing Zhao
- Department of Molecular MedicineScripps ResearchJupiterFloridaUSA
| | - Xiaodong Mu
- Center for Regenerative Sports MedicineSteadman Philippon Research InstituteVailColoradoUSA
- Shandong First Medical University (Shandong Academy of Medical Sciences)JinanChina
| | - Sara J. McGowan
- Department of Biochemistry, Molecular Biology and BiophysicsInstitute on the Biology of Aging and MetabolismUniversity of MinnesotaMinneapolisMinnesotaUSA
| | - Luise Angelini
- Department of Biochemistry, Molecular Biology and BiophysicsInstitute on the Biology of Aging and MetabolismUniversity of MinnesotaMinneapolisMinnesotaUSA
| | - Ryan D. O'Kelly
- Department of Biochemistry, Molecular Biology and BiophysicsInstitute on the Biology of Aging and MetabolismUniversity of MinnesotaMinneapolisMinnesotaUSA
| | - Matthew J. Yousefzadeh
- Department of Biochemistry, Molecular Biology and BiophysicsInstitute on the Biology of Aging and MetabolismUniversity of MinnesotaMinneapolisMinnesotaUSA
| | - Ayumi Sakamoto
- Department of Physical Medicine and Rehabilitation and Robert and Arlene Kogod Center on AgingRochesterMinnesotaUSA
| | - Zaira Aversa
- Department of Physical Medicine and Rehabilitation and Robert and Arlene Kogod Center on AgingRochesterMinnesotaUSA
| | - Nathan K. LeBrasseur
- Department of Physical Medicine and Rehabilitation and Robert and Arlene Kogod Center on AgingRochesterMinnesotaUSA
| | - Yousin Suh
- Department of Genetics and DevelopmentColumbia UniversityNew YorkNew YorkUSA
| | - Johnny Huard
- Center for Regenerative Sports MedicineSteadman Philippon Research InstituteVailColoradoUSA
| | | | - Laura J. Niedernhofer
- Department of Biochemistry, Molecular Biology and BiophysicsInstitute on the Biology of Aging and MetabolismUniversity of MinnesotaMinneapolisMinnesotaUSA
| | - Paul D. Robbins
- Department of Biochemistry, Molecular Biology and BiophysicsInstitute on the Biology of Aging and MetabolismUniversity of MinnesotaMinneapolisMinnesotaUSA
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Adult T-Cell Leukemia: a Comprehensive Overview on Current and Promising Treatment Modalities. Curr Oncol Rep 2021; 23:141. [PMID: 34735653 DOI: 10.1007/s11912-021-01138-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/14/2021] [Indexed: 10/19/2022]
Abstract
PURPOSE OF THE REVIEW Adult T-cell leukemia (ATL) is an aggressive chemo-resistant malignancy secondary to HTLV-1 retrovirus. Prognosis of ATL remains dismal. Herein, we emphasized on the current ATL treatment modalities and their drawbacks, and opened up on promising targeted therapies with special focus on the HTLV-1 regulatory proteins Tax and HBZ. RECENT FINDINGS Indolent ATL and a fraction of acute ATL exhibit long-term survival following antiviral treatment with zidovudine and interferon-alpha. Monoclonal antibodies such as mogamulizumab improved response rates, but with little effect on survival. Allogeneic hematopoietic cell transplantation results in long-term survival in one third of transplanted patients, alas only few patients are transplanted. Salvage therapy with lenalidomide in relapsed/refractory patients leads to prolonged survival in some of them. ATL remains an unmet medical need. Targeted therapies focusing on the HTLV-1 viral replication and/or viral regulatory proteins, as well as on the host antiviral immunity, represent a promising approach for the treatment of ATL.
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New Look of EBV LMP1 Signaling Landscape. Cancers (Basel) 2021; 13:cancers13215451. [PMID: 34771613 PMCID: PMC8582580 DOI: 10.3390/cancers13215451] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 09/01/2021] [Accepted: 10/26/2021] [Indexed: 01/18/2023] Open
Abstract
Simple Summary Epstein-Barr Virus (EBV) infection is associated with various lymphomas and carcinomas as well as other diseases in humans. The transmembrane protein LMP1 plays versatile roles in EBV life cycle and pathogenesis, by perturbing, reprograming, and regulating a large range of host cellular mechanisms and functions, which have been increasingly disclosed but not fully understood so far. We summarize recent research progress on LMP1 signaling, including the novel components LIMD1, p62, and LUBAC in LMP1 signalosome and LMP1 novel functions, such as its induction of p62-mediated selective autophagy, regulation of metabolism, induction of extracellular vehicles, and activation of NRF2-mediated antioxidative defense. A comprehensive understanding of LMP1 signal transduction and functions may allow us to leverage these LMP1-regulated cellular mechanisms for clinical purposes. Abstract The Epstein–Barr Virus (EBV) principal oncoprotein Latent Membrane Protein 1 (LMP1) is a member of the Tumor Necrosis Factor Receptor (TNFR) superfamily with constitutive activity. LMP1 shares many features with Pathogen Recognition Receptors (PRRs), including the use of TRAFs, adaptors, and kinase cascades, for signal transduction leading to the activation of NFκB, AP1, and Akt, as well as a subset of IRFs and likely the master antioxidative transcription factor NRF2, which we have gradually added to the list. In recent years, we have discovered the Linear UBiquitin Assembly Complex (LUBAC), the adaptor protein LIMD1, and the ubiquitin sensor and signaling hub p62, as novel components of LMP1 signalosome. Functionally, LMP1 is a pleiotropic factor that reprograms, balances, and perturbs a large spectrum of cellular mechanisms, including the ubiquitin machinery, metabolism, epigenetics, DNA damage response, extracellular vehicles, immune defenses, and telomere elongation, to promote oncogenic transformation, cell proliferation and survival, anchorage-independent cell growth, angiogenesis, and metastasis and invasion, as well as the development of the tumor microenvironment. We have recently shown that LMP1 induces p62-mediated selective autophagy in EBV latency, at least by contributing to the induction of p62 expression, and Reactive Oxygen Species (ROS) production. We have also been collecting evidence supporting the hypothesis that LMP1 activates the Keap1-NRF2 pathway, which serves as the key antioxidative defense mechanism. Last but not least, our preliminary data shows that LMP1 is associated with the deregulation of cGAS-STING DNA sensing pathway in EBV latency. A comprehensive understanding of the LMP1 signaling landscape is essential for identifying potential targets for the development of novel strategies towards targeted therapeutic applications.
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Forlani G, Shallak M, Tedeschi A, Cavallari I, Marçais A, Hermine O, Accolla RS. Dual cytoplasmic and nuclear localization of HTLV-1-encoded HBZ protein is a unique feature of adult T-cell leukemia. Haematologica 2021; 106:2076-2085. [PMID: 33626865 PMCID: PMC8327710 DOI: 10.3324/haematol.2020.272468] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Indexed: 01/28/2023] Open
Abstract
Adult T-cell leukemia-lymphoma (ATL), is a highly malignant T-cell neoplasm caused by human T-cell leukemia virus type 1 (HTLV-1), characterized by poor prognosis. Two viral proteins, Tax-1 and HTLV-1 basic-zipper factor (HBZ) play important roles in the pathogenesis of ATL. While Tax-1 can be found in both the cytoplasm and nucleus of HTLV-1 infected patients, HBZ is exclusively localized in the cytoplasm of HTLV-1 asymptomatic carriers and in patients with the chronic neurologic disease HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP). HBZ is only localized in the nucleus of ATL cell lines, suggesting that the nuclear localization of HBZ can be a hallmark of neoplastic transformation. In order to clarify this crucial point, we investigated in detail the pattern of HBZ expression in ATL patients. We made use of our monoclonal antibody 4D4-F3, that at present is the only reported reagent, among the few described, able to detect endogenous HBZ by immunofluorescence and confocal microscopy in cells from asymptomatic carriers, HAM/TSP and ATL patients. We found that HBZ is localized both in the cytoplasm and nucleus of cells of ATL patients irrespective of their clinical status, with a strong preference for the cytoplasmic localization. Also Tax-1 is localized in both compartments. As HBZ is exclusively localized in the cytoplasm in asymptomatic carriers and in non-neoplastic pathologies, this finding shows that neoplastic transformation consequent to HTLV-1 infection is accompanied and associated with the capacity of HBZ to translocate to the nucleus, which suggests a role of cytoplasmic-to-nuclear translocation in HTLV-1- mediated oncogenesis.
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Affiliation(s)
- Greta Forlani
- Laboratories of General Pathology and Immunology "Giovanna Tosi", Department of Medicine and Surgery, University of Insubria, Varese
| | - Mariam Shallak
- Laboratories of General Pathology and Immunology "Giovanna Tosi", Department of Medicine and Surgery, University of Insubria, Varese
| | - Alessandra Tedeschi
- Laboratories of General Pathology and Immunology "Giovanna Tosi", Department of Medicine and Surgery, University of Insubria, Varese
| | | | - Ambroise Marçais
- Department of Hematology, Necker-Enfants Malades, University Hospital, Assistance Publique Hopitaux de Paris, Paris Descartes University, Paris
| | - Olivier Hermine
- Department of Hematology, Necker-Enfants Malades, University Hospital, Assistance Publique Hopitaux de Paris, Paris Descartes University, Paris
| | - Roberto S Accolla
- Laboratories of General Pathology and Immunology "Giovanna Tosi", Department of Medicine and Surgery, University of Insubria, Varese.
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Viral Manipulation of the Host Epigenome as a Driver of Virus-Induced Oncogenesis. Microorganisms 2021; 9:microorganisms9061179. [PMID: 34070716 PMCID: PMC8227491 DOI: 10.3390/microorganisms9061179] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/24/2021] [Accepted: 05/26/2021] [Indexed: 12/13/2022] Open
Abstract
Tumorigenesis due to viral infection accounts for a high fraction of the total global cancer burden (15–20%) of all human cancers. A comprehensive understanding of the mechanisms by which viral infection leads to tumor development is extremely important. One of the main mechanisms by which viruses induce host cell proliferation programs is through controlling the host’s epigenetic machinery. In this review, we dissect the epigenetic pathways through which oncogenic viruses can integrate their genome into host cell chromosomes and lead to tumor progression. In addition, we highlight the potential use of drugs based on histone modifiers in reducing the global impact of cancer development due to viral infection.
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26
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He Y, Pasupala N, Zhi H, Dorjbal B, Hussain I, Shih HM, Bhattacharyya S, Biswas R, Miljkovic M, Semmes OJ, Waldmann TA, Snow AL, Giam CZ. NF-κB-induced R-loop accumulation and DNA damage select for nucleotide excision repair deficiencies in adult T cell leukemia. Proc Natl Acad Sci U S A 2021; 118:e2005568118. [PMID: 33649200 PMCID: PMC7958262 DOI: 10.1073/pnas.2005568118] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Constitutive NF-κB activation (NF-κBCA) confers survival and proliferation advantages to cancer cells and frequently occurs in T/B cell malignancies including adult T cell leukemia (ATL) caused by human T-cell leukemia virus type 1 (HTLV-1). Counterintuitively, NF-κBCA by the HTLV-1 transactivator/oncoprotein Tax induces a senescence response, and HTLV-1 infections in culture mostly result in senescence or cell-cycle arrest due to NF-κBCA How NF-κBCA induces senescence, and how ATL cells maintain NF-κBCA and avert senescence, remain unclear. Here we report that NF-κBCA by Tax increases R-loop accumulation and DNA double-strand breaks, leading to senescence. R-loop reduction via RNase H1 overexpression, and short hairpin RNA silencing of two transcription-coupled nucleotide excision repair (TC-NER) endonucleases that are critical for R-loop excision-Xeroderma pigmentosum F (XPF) and XPG-attenuate Tax senescence, enabling HTLV-1-infected cells to proliferate. Our data indicate that ATL cells are often deficient in XPF, XPG, or both and are hypersensitive to ultraviolet irradiation. This TC-NER deficiency is found in all ATL types. Finally, ATL cells accumulate R-loops in abundance. Thus, TC-NER deficits are positively selected during HTLV-1 infection because they facilitate the outgrowth of infected cells initially and aid the proliferation of ATL cells with NF-κBCA later. We suggest that TC-NER deficits and excess R-loop accumulation represent specific vulnerabilities that may be targeted for ATL treatment.
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Affiliation(s)
- Yunlong He
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814
| | - Nagesh Pasupala
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814
| | - Huijun Zhi
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814
| | - Batsuhk Dorjbal
- Department of Pharmacology and Molecular Therapeutics, Uniformed Services University of the Health Sciences, Bethesda, MD 20814
| | - Imran Hussain
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814
| | - Hsiu-Ming Shih
- Institute of Biomedical Sciences, Academia Sinica, Taipei 11529, Taiwan
- Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli County 350, Taiwan
| | - Sharmistha Bhattacharyya
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD 20814
| | - Roopa Biswas
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD 20814
| | - Milos Miljkovic
- Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892
| | - Oliver John Semmes
- Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, VA 23501
- The Leroy T. Canoles Jr. Cancer Research Center, Eastern Virginia Medical School, Norfolk, VA 23501
| | - Thomas A Waldmann
- Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892
| | - Andrew L Snow
- Department of Pharmacology and Molecular Therapeutics, Uniformed Services University of the Health Sciences, Bethesda, MD 20814
| | - Chou-Zen Giam
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814;
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Akkouche A, Moodad S, Hleihel R, Skayneh H, Chambeyron S, El Hajj H, Bazarbachi A. In vivo antagonistic role of the Human T-Cell Leukemia Virus Type 1 regulatory proteins Tax and HBZ. PLoS Pathog 2021; 17:e1009219. [PMID: 33471856 PMCID: PMC7817025 DOI: 10.1371/journal.ppat.1009219] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 12/04/2020] [Indexed: 12/30/2022] Open
Abstract
Adult T cell leukemia (ATL) is an aggressive malignancy secondary to chronic infection by the human T-cell leukemia virus type 1 (HTLV-1) infection. Two viral proteins, Tax and HBZ, play central roles in ATL leukemogenesis. Tax expression transforms T cells in vitro and induces ATL-like disease in mice. Tax also induces a rough eye phenotype and increases hemocyte count in Drosophila melanogaster, indicative of transformation. Among multiple functions, Tax modulates the expression of the enhancer of zeste homolog 2 (EZH2), a methyltransferase of the Polycomb Repressive Complex 2 (PRC2), leading to H3K27me3-dependent reprogramming of around half of cellular genes. HBZ is a negative regulator of Tax-mediated viral transcription. HBZ effects on epigenetic signatures are underexplored. Here, we established an hbz transgenic fly model, and demonstrated that, unlike Tax, which induces NF-κB activation and enhanced PRC2 activity creating an activation loop, HBZ neither induces transformation nor NF-κB activation in vivo. However, overexpression of Tax or HBZ increases the PRC2 activity and both proteins directly interact with PRC2 complex core components. Importantly, overexpression of HBZ in tax transgenic flies prevents Tax-induced NF-κB or PRC2 activation and totally rescues Tax-induced transformation and senescence. Our results establish the in vivo antagonistic effect of HBZ on Tax-induced transformation and cellular effects. This study helps understanding long-term HTLV-1 persistence and cellular transformation and opens perspectives for new therapeutic strategies targeting the epigenetic machinery in ATL. Adult T cell leukemia-lymphoma is an aggressive hematological malignancy, caused by the retroviral infection with HTLV-1. Tax and HBZ play critical roles in leukemia development. Tax activates the NF-κB pathway and modulates the epigenetic machinery to induce cellular proliferation and malignant transformation. We generated hbz or tax/hbz transgenic fly models and explored the phenotypes and epigenetic changes in vivo. Unlike Tax, HBZ expression failed to activate NF-κB or to induce transformation or senescence in vivo, yet activated PRC2 core components resulting in subsequent epigenetic changes. HBZ expression in tax Tg flies inhibits Tax-induced NF-κB or PRC2 activation, resulting in inhibition of malignant cellular proliferation and its consequent senescence. Our study proves the antagonistic effect of HBZ on Tax-induced transformation in vivo, providing further understanding on ATL pathogenesis.
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Affiliation(s)
- Abdou Akkouche
- Department of Internal Medicine, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
- Department of Anatomy, Cell Biology and Physiological Sciences, American University of Beirut, Beirut, Lebanon
| | - Sara Moodad
- Department of Internal Medicine, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
- Department of Anatomy, Cell Biology and Physiological Sciences, American University of Beirut, Beirut, Lebanon
| | - Rita Hleihel
- Department of Internal Medicine, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
- Department of Anatomy, Cell Biology and Physiological Sciences, American University of Beirut, Beirut, Lebanon
| | - Hala Skayneh
- Department of Internal Medicine, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
- Department of Anatomy, Cell Biology and Physiological Sciences, American University of Beirut, Beirut, Lebanon
| | - Séverine Chambeyron
- Institute of Human Genetics, CNRS, UMR 9002, Montpellier University, Montpellier, France
| | - Hiba El Hajj
- Department of Experimental Pathology, Immunology and Microbiology, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
- * E-mail: (HEH); (AB)
| | - Ali Bazarbachi
- Department of Internal Medicine, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
- Department of Anatomy, Cell Biology and Physiological Sciences, American University of Beirut, Beirut, Lebanon
- * E-mail: (HEH); (AB)
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Abstract
Human T-cell leukemia virus type 1 (HTLV-1) was discovered in 1980 as the first, and to date, the only retrovirus that causes human cancer. While HTLV-1 infection is generally asymptomatic, 3-5% of infected individuals develop a T cell neoplasm known as adult T cell leukemia/lymphoma (ATL) decades after infection. Since its discovery, HTLV-1 has served as a model for understanding retroviral oncogenesis, transcriptional regulation, cellular signal transduction, and cell-associated viral infection and spread. Much of the initial research was focused on the viral trans-activator/oncoprotein, Tax. Over the past decade, the study of HTLV-1 has entered the genomic era. With the development of new systems for studying HTLV-1 infection and pathogenesis, the completion of the whole genome, exome and transcriptome sequencing analyses of ATL, and the discovery of HBZ as another HTLV-1 oncogene, many established concepts about how HTLV-1 infects, persists and causes disease have undergone substantial revision. This chapter seeks to integrate our current understanding of the mechanisms of action of Tax and HBZ with the comprehensive genomic information of ATL to provide an overview of how HTLV-1 infects, replicates and causes leukemia.
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Elucidating the Basis for Permissivity of the MT-4 T-Cell Line to Replication of an HIV-1 Mutant Lacking the gp41 Cytoplasmic Tail. J Virol 2020; 94:JVI.01334-20. [PMID: 32938764 DOI: 10.1128/jvi.01334-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 09/07/2020] [Indexed: 12/11/2022] Open
Abstract
HIV-1 encodes an envelope glycoprotein (Env) that contains a long cytoplasmic tail (CT) harboring trafficking motifs implicated in Env incorporation into virus particles and viral transmission. In most physiologically relevant cell types, the gp41 CT is required for HIV-1 replication, but in the MT-4 T-cell line the gp41 CT is not required for a spreading infection. To help elucidate the role of the gp41 CT in HIV-1 transmission, in this study, we investigated the viral and cellular factors that contribute to the permissivity of MT-4 cells to gp41 CT truncation. We found that the kinetics of HIV-1 production and virus release are faster in MT-4 than in the other T-cell lines tested, but MT-4 cells express equivalent amounts of HIV-1 proteins on a per-cell basis relative to cells not permissive to CT truncation. MT-4 cells express higher levels of plasma-membrane-associated Env than nonpermissive cells, and Env internalization from the plasma membrane is less efficient than that from another T-cell line, SupT1. Paradoxically, despite the high levels of Env on the surface of MT-4 cells, 2-fold less Env is incorporated into virus particles produced from MT-4 than SupT1 cells. Contact-dependent transmission between cocultured 293T and MT-4 cells is higher than in cocultures of 293T with most other T-cell lines tested, indicating that MT-4 cells are highly susceptible to cell-to-cell infection. These data help to clarify the long-standing question of how MT-4 cells overcome the requirement for the HIV-1 gp41 CT and support a role for gp41 CT-dependent trafficking in Env incorporation and cell-to-cell transmission in physiologically relevant cell lines.IMPORTANCE The HIV-1 Env cytoplasmic tail (CT) is required for efficient Env incorporation into nascent particles and viral transmission in primary CD4+ T cells. The MT-4 T-cell line has been reported to support multiple rounds of infection of HIV-1 encoding a gp41 CT truncation. Uncovering the underlying mechanism of MT-4 T-cell line permissivity to gp41 CT truncation would provide key insights into the role of the gp41 CT in HIV-1 transmission. This study reveals that multiple factors contribute to the unique ability of a gp41 CT truncation mutant to spread in cultures of MT-4 cells. The lack of a requirement for the gp41 CT in MT-4 cells is associated with the combined effects of rapid HIV-1 protein production, high levels of cell-surface Env expression, and increased susceptibility to cell-to-cell transmission compared to nonpermissive cells.
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Hirons A, Khoury G, Purcell DFJ. Human T-cell lymphotropic virus type-1: a lifelong persistent infection, yet never truly silent. THE LANCET. INFECTIOUS DISEASES 2020; 21:e2-e10. [PMID: 32986997 DOI: 10.1016/s1473-3099(20)30328-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 04/06/2020] [Accepted: 04/16/2020] [Indexed: 12/12/2022]
Abstract
Human T-cell lymphotropic virus type-1 (HTLV-1) has a large global burden and in some key communities, such as Indigenous Australians living in remote areas, greater than 45% of people are infected. Despite HTLV-1 causing serious malignancy and myelopathic paraparesis, and a significant association with a range of inflammatory comorbidities and secondary infections that shorten lifespan, few biomedical interventions are available. HTLV-1 starkly contrasts with other blood-borne sexually transmitted viral infections, such as, HIV, hepatitis B virus, and hepatitis C virus, with no antiviral treatments that reduce virus-infected cells, no rapid diagnostics or biomarker assays suitable for use in remote settings, and no effective vaccine. We review how the replication strategies and molecular properties of HTLV-1 establish a long-term stealthy viral pathogenesis through a fine-tuned balance of persistence, immune cell dysfunction, and proliferation of proviral infected cells that collectively present robust barriers to treatment and prevention. An understanding of the nature of the HTLV-1 provirus and opposing actions of viral-coded negative-sense HBZ and positive-sense regulatory proteins Tax, p12 and its cleaved product p8, and p30, is needed to improve the biomedical tools for preventing transmission and improving the long-term health of people with this lifelong infection.
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Affiliation(s)
- Ashley Hirons
- The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia
| | - Georges Khoury
- The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia
| | - Damian F J Purcell
- The Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, VIC, Australia.
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Millen S, Meretuk L, Göttlicher T, Schmitt S, Fleckenstein B, Thoma-Kress AK. A novel positive feedback-loop between the HTLV-1 oncoprotein Tax and NF-κB activity in T-cells. Retrovirology 2020; 17:30. [PMID: 32912211 PMCID: PMC7488018 DOI: 10.1186/s12977-020-00538-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 08/28/2020] [Indexed: 12/30/2022] Open
Abstract
Background Human T-cell leukemia virus type 1 (HTLV-1) infects primarily CD4+ T-lymphocytes and evoques severe diseases, predominantly Adult T-Cell Leukemia/ Lymphoma (ATL/L) and HTLV-1-associated Myelopathy/ Tropical Spastic Paraparesis (HAM/TSP). The viral transactivator of the pX region (Tax) is important for initiating malignant transformation, and deregulation of the major signaling pathway nuclear factor of kappa B (NF-κB) by Tax represents a hallmark of HTLV-1 driven cancer. Results Here we found that Tax mutants which are defective in NF-κB signaling showed diminished protein expression levels compared to Tax wildtype in T-cells, whereas Tax transcript levels were comparable. Strikingly, constant activation of NF-κB signaling by the constitutive active mutant of inhibitor of kappa B kinase (IKK2, IKK-β), IKK2-EE, rescued protein expression of the NF-κB defective Tax mutants M22 and K1-10R and even increased protein levels of Tax wildtype in various T-cell lines while Tax transcript levels were only slightly affected. Using several Tax expression constructs, an increase of Tax protein occurred independent of Tax transcripts and independent of the promoter used. Further, Tax and M22 protein expression were strongly enhanced by 12-O-Tetradecanoylphorbol-13-Acetate [TPA; Phorbol 12-myristate 13-acetate (PMA)]/ ionomycin, inducers of NF-κB and cytokine signaling, but not by tumor necrosis factor alpha (TNF-α). On the other hand, co-expression of Tax with a dominant negative inhibitor of κB, IκBα-DN, or specific inhibition of IKK2 by the compound ACHP, led to a vast decrease in Tax protein levels to some extent independent of Tax transcripts in transiently transfected and Tax-transformed T-cells. Cycloheximide chase experiments revealed that co-expression of IKK2-EE prolongs the half-life of M22, and constant repression of NF-κB signaling by IκBα-DN strongly reduces protein stability of Tax wildtype suggesting that NF-κB activity is required for Tax protein stability. Finally, protein expression of Tax and M22 could be recovered by NH4Cl and PYR-41, inhibitors of the lysosome and the ubiquitin-activating enzyme E1, respectively. Conclusions Together, these findings suggest that Tax’s capability to induce NF-κB is critical for protein expression and stabilization of Tax itself. Overall, identification of this novel positive feedback loop between Tax and NF-κB in T-cells improves our understanding of Tax-driven transformation.
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Affiliation(s)
- Sebastian Millen
- Institute of Clinical and Molecular Virology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Lina Meretuk
- Institute of Clinical and Molecular Virology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Tim Göttlicher
- Institute of Clinical and Molecular Virology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Sarah Schmitt
- Institute of Clinical and Molecular Virology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Bernhard Fleckenstein
- Institute of Clinical and Molecular Virology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Andrea K Thoma-Kress
- Institute of Clinical and Molecular Virology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
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32
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Stolz ML, McCormick C. The bZIP Proteins of Oncogenic Viruses. Viruses 2020; 12:v12070757. [PMID: 32674309 PMCID: PMC7412551 DOI: 10.3390/v12070757] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 07/08/2020] [Accepted: 07/13/2020] [Indexed: 12/20/2022] Open
Abstract
Basic leucine zipper (bZIP) transcription factors (TFs) govern diverse cellular processes and cell fate decisions. The hallmark of the leucine zipper domain is the heptad repeat, with leucine residues at every seventh position in the domain. These leucine residues enable homo- and heterodimerization between ZIP domain α-helices, generating coiled-coil structures that stabilize interactions between adjacent DNA-binding domains and target DNA substrates. Several cancer-causing viruses encode viral bZIP TFs, including human T-cell leukemia virus (HTLV), hepatitis C virus (HCV) and the herpesviruses Marek’s disease virus (MDV), Epstein–Barr virus (EBV) and Kaposi’s sarcoma-associated herpesvirus (KSHV). Here, we provide a comprehensive review of these viral bZIP TFs and their impact on viral replication, host cell responses and cell fate.
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Mohanty S, Harhaj EW. Mechanisms of Oncogenesis by HTLV-1 Tax. Pathogens 2020; 9:E543. [PMID: 32645846 PMCID: PMC7399876 DOI: 10.3390/pathogens9070543] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 06/24/2020] [Accepted: 07/01/2020] [Indexed: 01/23/2023] Open
Abstract
The human T-cell lymphotropic virus type 1 (HTLV-1) is the etiological agent of adult T-cell leukemia/lymphoma (ATLL), a neoplasm of CD4+CD25+ T cells that occurs in 2-5% of infected individuals after decades of asymptomatic latent infection. Multiple HTLV-1-encoded regulatory proteins, including Tax and HTLV-1 basic leucine zipper factor (HBZ), play key roles in viral persistence and latency. The HTLV-1 Tax oncoprotein interacts with a plethora of host cellular proteins to regulate viral gene expression and also promote the aberrant activation of signaling pathways such as NF-κB to drive clonal proliferation and survival of T cells bearing the HTLV-1 provirus. Tax undergoes various post-translational modifications such as phosphorylation and ubiquitination that regulate its function and subcellular localization. Tax shuttles in different subcellular compartments for the activation of anti-apoptotic genes and deregulates the cell cycle with the induction of DNA damage for the accumulation of genomic instability that can result in cellular immortalization and malignant transformation. However, Tax is highly immunogenic and therefore HTLV-1 has evolved numerous strategies to tightly regulate Tax expression while maintaining the pool of anti-apoptotic genes through HBZ. In this review, we summarize the key findings on the oncogenic mechanisms used by Tax that set the stage for the development of ATLL, and the strategies used by HTLV-1 to tightly regulate Tax expression for immune evasion and viral persistence.
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Affiliation(s)
| | - Edward W. Harhaj
- Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, PA 17033, USA;
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Zhi H, Guo X, Ho YK, Pasupala N, Engstrom HAA, Semmes OJ, Giam CZ. RNF8 Dysregulation and Down-regulation During HTLV-1 Infection Promote Genomic Instability in Adult T-Cell Leukemia. PLoS Pathog 2020; 16:e1008618. [PMID: 32453758 PMCID: PMC7274470 DOI: 10.1371/journal.ppat.1008618] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 06/05/2020] [Accepted: 05/11/2020] [Indexed: 12/22/2022] Open
Abstract
The genomic instability associated with adult T cell leukemia/lymphoma (ATL) is causally linked to Tax, the HTLV-1 viral oncoprotein, but the underlying mechanism is not fully understood. We have previously shown that Tax hijacks and aberrantly activates ring finger protein 8 (RNF8) — a lysine 63 (K63)-specific ubiquitin E3 ligase critical for DNA double-strand break (DSB) repair signaling — to assemble K63-linked polyubiquitin chains (K63-pUbs) in the cytosol. Tax and the cytosolic K63-pUbs, in turn, initiate additional recruitment of linear ubiquitin assembly complex (LUBAC) to produce hybrid K63-M1 pUbs, which trigger a kinase cascade that leads to canonical IKK:NF-κB activation. Here we demonstrate that HTLV-1-infected cells are impaired in DNA damage response (DDR). This impairment correlates with the induction of microscopically visible nuclear speckles by Tax known as the Tax-speckle structures (TSS), which act as pseudo DNA damage signaling scaffolds that sequester DDR factors such as BRCA1, DNA-PK, and MDC1. We show that TSS co-localize with Tax, RNF8 and K63-pUbs, and their formation depends on RNF8. Tax mutants defective or attenuated in inducing K63-pUb assembly are deficient or tempered in TSS induction and DDR impairment. Finally, our results indicate that loss of RNF8 expression reduces HTLV-1 viral gene expression and frequently occurs in ATL cells. Thus, during HTLV-1 infection, Tax activates RNF8 to assemble nuclear K63-pUbs that sequester DDR factors in Tax speckles, disrupting DDR signaling and DSB repair. Down-regulation of RNF8 expression is positively selected during infection and progression to disease, and further exacerbates the genomic instability of ATL. Approximately 3–5% of HTLV-1-infected individuals develop an intractable malignancy called adult T cell leukemia/lymphoma (ATL) decades after infection. Unlike other leukemia, ATL is characterized by extensive genomic instability. Here we show that the genomic instability of ATL is associated with the hijacking and aberrant activation of a molecule known as ring finger protein 8 (RNF8) by HTLV-1 for viral replication. RNF8 is crucial for initiating the cellular DNA damage response (DDR) required for the repair of DNA double-strand breaks (DSBs), the most deleterious DNA damage. Its dysregulation in HTLV-1-infected cells results in the formation of pseudo DNA damage signaling scaffolds known as Tax speckle structures that sequester critical repair factors, causing an inability to repair DSBs efficiently. We have further found that loss of RNF8 expression reduces HTLV-1 viral replication and frequently occurs in ATL of all types. This likely facilitates the immune evasion of virus-infected cells, but degrades their ability to repair DSBs and exacerbates the genomic instability of ATL cells. Since DDR defects impact cancer response to DNA-damaging radiation and chemotherapies, RNF8 deficiency in ATL may be exploited for disease treatment.
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Affiliation(s)
- Huijun Zhi
- Department of Microbiology and Immunology Uniformed Services University of the Health Sciences Bethesda, MD, United States of America
| | - Xin Guo
- Department of Microbiology and Molecular Cell Biology The Leroy T. Canoles Jr Cancer Research Center Eastern Virginia Medical School Norfolk, VA, United States of America
| | - Yik-Khuan Ho
- Department of Microbiology and Immunology Uniformed Services University of the Health Sciences Bethesda, MD, United States of America
| | - Nagesh Pasupala
- Department of Microbiology and Immunology Uniformed Services University of the Health Sciences Bethesda, MD, United States of America
| | - Hampus Alexander Anders Engstrom
- Department of Microbiology and Molecular Cell Biology The Leroy T. Canoles Jr Cancer Research Center Eastern Virginia Medical School Norfolk, VA, United States of America
| | - Oliver John Semmes
- Department of Microbiology and Molecular Cell Biology The Leroy T. Canoles Jr Cancer Research Center Eastern Virginia Medical School Norfolk, VA, United States of America
- * E-mail: (OJS); (C-ZG)
| | - Chou-Zen Giam
- Department of Microbiology and Immunology Uniformed Services University of the Health Sciences Bethesda, MD, United States of America
- * E-mail: (OJS); (C-ZG)
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35
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Yasunaga JI. Strategies of Human T-Cell Leukemia Virus Type 1 for Persistent Infection: Implications for Leukemogenesis of Adult T-Cell Leukemia-Lymphoma. Front Microbiol 2020; 11:979. [PMID: 32508789 PMCID: PMC7248384 DOI: 10.3389/fmicb.2020.00979] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 04/23/2020] [Indexed: 01/21/2023] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) establishes persistent infection in vivo in two distinct ways: de novo infection and clonal proliferation of infected cells. Two viral genes, Tax and HTLV-1 bZIP factor (HBZ) play critical roles in viral transcription and promotion of T-cell proliferation, respectively. Tax is a potent transactivator not only for viral transcription but also for many cellular oncogenic pathways, such as the NF-κB pathway. HBZ is a suppressor of viral transcription and has the potential to change the immunophenotype of infected cells, conferring an effector regulatory T cell (eTreg)-like signature (CD4+ CD25+ CCR4+ TIGIT+ Foxp3+) and enhancing the proliferation of this subset. Reports that mice transgenic for either gene develop malignant tumors suggest that both Tax and HBZ are involved in leukemogenesis by HTLV-1. However, the immunogenicity of Tax is very high, and its expression is generally suppressed in vivo. Recently, it was found that Tax can be expressed transiently in a small subpopulation of adult T-cell leukemia-lymphoma (ATL) cells and plays a critical role in maintenance of the overall population. HBZ is expressed in almost all infected cells except for the rare Tax-expressing cells, and activates the pathways associated with cell proliferation. These findings indicate that HTLV-1 fine-tunes the expression of viral genes to control the mode of viral propagation. The interplay between Tax and HBZ is the basis of a sophisticated strategy to evade host immune surveillance and increase transmission - and can lead to ATL as a byproduct.
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Affiliation(s)
- Jun-Ichirou Yasunaga
- Department of Hematology, Rheumatology and Infectious Disease, Faculty of Life Sciences, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan
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36
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The Complex Relationship between HTLV-1 and Nonsense-Mediated mRNA Decay (NMD). Pathogens 2020; 9:pathogens9040287. [PMID: 32326562 PMCID: PMC7238105 DOI: 10.3390/pathogens9040287] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 04/09/2020] [Accepted: 04/12/2020] [Indexed: 02/07/2023] Open
Abstract
Before the establishment of an adaptive immune response, retroviruses can be targeted by several cellular host factors at different stages of the viral replication cycle. This intrinsic immunity relies on a large diversity of antiviral processes. In the case of HTLV-1 infection, these active innate host defense mechanisms are debated. Among these mechanisms, we focused on an RNA decay pathway called nonsense-mediated mRNA decay (NMD), which can target multiple viral RNAs, including HTLV-1 unspliced RNA, as has been recently demonstrated. NMD is a co-translational process that depends on the RNA helicase UPF1 and regulates the expression of multiple types of host mRNAs. RNA sensitivity to NMD depends on mRNA organization and the ribonucleoprotein (mRNP) composition. HTLV-1 has evolved several means to evade the NMD threat, leading to NMD inhibition. In the early steps of infection, NMD inhibition favours the production of HTLV-1 infectious particles, which may contribute to the survival of the fittest clones despite genome instability; however, its direct long-term impact remains to be investigated.
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37
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Cells of adult T-cell leukemia evade HTLV-1 Tax/NF-κB hyperactivation-induced senescence. Blood Adv 2020; 3:564-569. [PMID: 30787019 DOI: 10.1182/bloodadvances.2018029322] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 01/18/2019] [Indexed: 11/20/2022] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) is the etiological agent of adult T-cell leukemia/lymphoma (ATL). The HTLV-1 viral trans-activator/oncoprotein Tax is a major driver of ATL, yet it induces rapid p21Cip1/Waf1 (p21)- and p27Kip1-mediated cellular senescence through constitutive activation (hyperactivation) of NF-κB. Although constitutive NF-κB activation is a common feature of T/B-cell leukemia/lymphoma, including ATL, it is not known how ATL cells maintain chronic NF-κB activation without undergoing senescence. Here, we demonstrate that, in contrast to HTLV-1- T-cell lines, ATL cell lines no longer undergo Tax-induced senescence. Although Tax+ and Tax- ATL cell lines showed signatures of constitutive NF-κB activation, their ability to progress through the cell cycle was unaffected. In some cases, ATL cell lines continued to proliferate despite significant upregulation of p21; additionally, many cell lines displayed altered expression of G1 and G1/S cyclins, particularly overexpression of cyclin D2. We propose that, during the course of ATL development, leukemia cells acquire genetic/epigenetic changes that can mitigate the senescence response triggered by NF-κB hyperactivation. Restoring the NF-κB-induced senescence response would likely help to control the development and progression of ATL and similar lymphoid malignancies.
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38
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Fochi S, Ciminale V, Trabetti E, Bertazzoni U, D’Agostino DM, Zipeto D, Romanelli MG. NF-κB and MicroRNA Deregulation Mediated by HTLV-1 Tax and HBZ. Pathogens 2019; 8:E290. [PMID: 31835460 PMCID: PMC6963194 DOI: 10.3390/pathogens8040290] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Revised: 11/27/2019] [Accepted: 12/06/2019] [Indexed: 12/17/2022] Open
Abstract
The risk of developing adult T-cell leukemia/lymphoma (ATLL) in individuals infected with human T-cell lymphotropic virus 1 (HTLV-1) is about 3-5%. The mechanisms by which the virus triggers this aggressive cancer are still an area of intensive investigation. The viral protein Tax-1, together with additional regulatory proteins, in particular HTLV-1 basic leucine zipper factor (HBZ), are recognized as relevant viral factors required for both viral replication and transformation of infected cells. Tax-1 deregulates several cellular pathways affecting the cell cycle, survival, and proliferation. The effects of Tax-1 on the NF-κB pathway have been thoroughly studied. Recent studies also revealed the impact of Tax-1 and HBZ on microRNA expression. In this review, we summarize the recent progress in understanding the contribution of HTLV-1 Tax- and HBZ-mediated deregulation of NF-κB and the microRNA regulatory network to HTLV-1 pathogenesis.
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Affiliation(s)
- Stefania Fochi
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biology and Genetics, University of Verona, 37134 Verona, Italy; (S.F.); (E.T.); (U.B.); (D.Z.)
| | - Vincenzo Ciminale
- Department of Surgery, Oncology and Gastroenterology, University of Padua, 35128 Padua, Italy;
- Veneto Institute of Oncology IOV-IRCCS, 35128 Padua, Italy
| | - Elisabetta Trabetti
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biology and Genetics, University of Verona, 37134 Verona, Italy; (S.F.); (E.T.); (U.B.); (D.Z.)
| | - Umberto Bertazzoni
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biology and Genetics, University of Verona, 37134 Verona, Italy; (S.F.); (E.T.); (U.B.); (D.Z.)
| | | | - Donato Zipeto
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biology and Genetics, University of Verona, 37134 Verona, Italy; (S.F.); (E.T.); (U.B.); (D.Z.)
| | - Maria Grazia Romanelli
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biology and Genetics, University of Verona, 37134 Verona, Italy; (S.F.); (E.T.); (U.B.); (D.Z.)
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Ratner L. Biomarkers and Preclinical Models for Adult T-Cell Leukemia-Lymphoma Treatment. Front Microbiol 2019; 10:2109. [PMID: 31620102 PMCID: PMC6759749 DOI: 10.3389/fmicb.2019.02109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 08/27/2019] [Indexed: 11/13/2022] Open
Abstract
Adult T-cell leukemia/lymphoma (ATL) is an aggressive lymphoproliferative malignancy with a very poor prognosis. Despite several recent advances, new therapeutic approaches are critical, and this will require successful preclinical studies, including studies in ATL cell culture systems, and mouse models. Identification of accurate, reproducible biomarkers will be a crucial component of preclinical and clinical studies. This review summarizes the current state-of-the-art in each of these fields, and provides recommendations for future approaches. This problem is an important unmet need in HTLV research.
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Affiliation(s)
- Lee Ratner
- Division of Oncology, School of Medicine, Washington University in St. Louis, St. Louis, MO, United States
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40
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Bangham CRM, Miura M, Kulkarni A, Matsuoka M. Regulation of Latency in the Human T Cell Leukemia Virus, HTLV-1. Annu Rev Virol 2019; 6:365-385. [PMID: 31283437 DOI: 10.1146/annurev-virology-092818-015501] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The human T cell leukemia virus persists in vivo in 103 to 106 clones of T lymphocytes that appear to survive for the lifetime of the host. The plus strand of the provirus is typically transcriptionally silent in freshly isolated lymphocytes, but the strong, persistently activated cytotoxic T lymphocyte (CTL) response to the viral antigens indicates that the virus is not constantly latent in vivo. There is now evidence that the plus strand is transcribed in intense intermittent bursts that are triggered by cellular stress, modulated by hypoxia and glycolysis, and inhibited by polycomb repressive complex 1 (PRC1). The minus-strand gene hbz is transcribed at a lower, more constant level but is silent in a proportion of infected cells at a given time. Viral genes in the sense and antisense strands of the provirus play different respective roles in latency and de novo infection: Expression of the plus-strand gene tax is essential for de novo infection, whereas hbz appears to facilitate survival of the infected T cell clone in vivo.
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Affiliation(s)
- Charles R M Bangham
- Division of Infectious Diseases, Department of Medicine, Imperial College London, London W2 1PG, United Kingdom;
| | - Michi Miura
- Division of Infectious Diseases, Department of Medicine, Imperial College London, London W2 1PG, United Kingdom;
| | - Anurag Kulkarni
- Division of Infectious Diseases, Department of Medicine, Imperial College London, London W2 1PG, United Kingdom;
| | - Masao Matsuoka
- Laboratory of Virus Control, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan.,Department of Hematology, Rheumatology and Infectious Diseases, Kumamoto University School of Medicine, Kumamoto 860-8556, Japan;
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41
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Mota TM, Jones RB. HTLV-1 as a Model for Virus and Host Coordinated Immunoediting. Front Immunol 2019; 10:2259. [PMID: 31616431 PMCID: PMC6768981 DOI: 10.3389/fimmu.2019.02259] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 09/06/2019] [Indexed: 12/17/2022] Open
Abstract
Immunoediting is a process that occurs in cancer, whereby the immune system acts to initially repress, and subsequently promote the outgrowth of tumor cells through the stages of elimination, equilibrium, and escape. Here we present a model for a virus that causes cancer where immunoediting is coordinated through synergistic viral- and host-mediated events. We argue that the initial viral replication process of the Human T cell leukemia virus type I (HTLV-1), which causes adult T cell leukemia/lymphoma (ATL) in ~5% of individuals after decades of latency, harmonizes with the host immune system to create a population of cells destined for malignancy. Furthermore, we explore the possibility for HIV to fit into this model of immunoediting, and propose a non-malignant escape phase for HIV-infected cells that persist beyond equilibrium.
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Affiliation(s)
- Talia M Mota
- Infectious Diseases Division, Department of Medicine, Weill Cornell Medical College, New York, NY, United States
| | - R Brad Jones
- Infectious Diseases Division, Department of Medicine, Weill Cornell Medical College, New York, NY, United States.,Program in Immunology and Microbial Pathogenesis, Weill Cornell Graduate School of Medical Sciences, New York, NY, United States
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42
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Harrod R. Silencers of HTLV-1 and HTLV-2: the pX-encoded latency-maintenance factors. Retrovirology 2019; 16:25. [PMID: 31492165 PMCID: PMC6731619 DOI: 10.1186/s12977-019-0487-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 08/30/2019] [Indexed: 11/10/2022] Open
Abstract
Of the members of the primate T cell lymphotropic virus (PTLV) family, only the human T-cell leukemia virus type-1 (HTLV-1) causes disease in humans—as the etiological agent of adult T-cell leukemia/lymphoma (ATLL), HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), and other auto-inflammatory disorders. Despite having significant genomic organizational and structural similarities, the closely related human T-cell lymphotropic virus type-2 (HTLV-2) is considered apathogenic and has been linked with benign lymphoproliferation and mild neurological symptoms in certain infected patients. The silencing of proviral gene expression and maintenance of latency are central for the establishment of persistent infections in vivo. The conserved pX sequences of HTLV-1 and HTLV-2 encode several ancillary factors which have been shown to negatively regulate proviral gene expression, while simultaneously activating host cellular proliferative and pro-survival pathways. In particular, the ORF-II proteins, HTLV-1 p30II and HTLV-2 p28II, suppress Tax-dependent transactivation from the viral promoter—whereas p30II also inhibits PU.1-mediated inflammatory-signaling, differentially augments the expression of p53-regulated metabolic/pro-survival genes, and induces lymphoproliferation which could promote mitotic proviral replication. The ubiquitinated form of the HTLV-1 p13II protein localizes to nuclear speckles and interferes with recruitment of the p300 coactivator by the viral transactivator Tax. Further, the antisense-encoded HTLV-1 HBZ and HTLV-2 APH-2 proteins and mRNAs negatively regulate Tax-dependent proviral gene expression and activate inflammatory signaling associated with enhanced T-cell lymphoproliferation. This review will summarize our current understanding of the pX latency-maintenance factors of HTLV-1 and HTLV-2 and discuss how these products may contribute to the differences in pathogenicity between the human PTLVs.
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Affiliation(s)
- Robert Harrod
- Laboratory of Molecular Virology, Department of Biological Sciences, and The Dedman College Center for Drug Discovery, Design & Delivery, Southern Methodist University, 6501 Airline Drive, 334-DLS, Dallas, TX, 75275-0376, USA.
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The human T-cell leukemia virus type-1 tax oncoprotein dissociates NF-κB p65 RelA-Stathmin complexes and causes catastrophic mitotic spindle damage and genomic instability. Virology 2019; 535:83-101. [PMID: 31299491 DOI: 10.1016/j.virol.2019.07.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 06/21/2019] [Accepted: 07/02/2019] [Indexed: 12/23/2022]
Abstract
Genomic instability is a hallmark of many cancers; however, the molecular etiology of chromosomal dysregulation is not well understood. The human T-cell leukemia virus type-1 (HTLV-1) oncoprotein Tax activates NF-κB-signaling and induces DNA-damage and aberrant chromosomal segregation through diverse mechanisms which contribute to viral carcinogenesis. Intriguingly, Stathmin/oncoprotein-18 (Op-18) depolymerizes tubulin and interacts with the p65RelA subunit and functions as a cofactor for NF-κB-dependent transactivation. We thus hypothesized that the dissociation of p65RelA-Stathmin/Op-18 complexes by Tax could lead to the catastrophic destabilization of microtubule (MT) spindle fibers during mitosis and provide a novel mechanistic link between NF-κB-signaling and genomic instability. Here we report that the inhibition of Stathmin expression by the retroviral latency protein, p30II, or knockdown with siRNA-stathmin, dampens Tax-mediated NF-κB transactivation and counters Tax-induced genomic instability and cytotoxicity. The Tax-G148V mutant, defective for NF-κB activation, exhibited reduced p65RelA-Stathmin binding and diminished genomic instability and cytotoxicity. Dominant-negative inhibitors of NF-κB also prevented Tax-induced multinucleation and apoptosis. Moreover, cell clones containing the infectious HTLV-1 ACH. p30II mutant provirus, impaired for p30II production, exhibited increased multinucleation and the accumulation of cytoplasmic tubulin aggregates following nocodozole-treatment. These findings allude to a mechanism whereby NF-κB-signaling regulates tubulin dynamics and mitotic instability through the modulation of p65RelA-Stathmin/Op-18 interactions, and support the notion that p30II enhances the survival of Tax-expressing HTLV-1-transformed cells.
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Rushing AW, Rushing B, Hoang K, Sanders SV, Péloponèse JM, Polakowski N, Lemasson I. HTLV-1 basic leucine zipper factor protects cells from oxidative stress by upregulating expression of Heme Oxygenase I. PLoS Pathog 2019; 15:e1007922. [PMID: 31251786 PMCID: PMC6623464 DOI: 10.1371/journal.ppat.1007922] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 07/11/2019] [Accepted: 06/18/2019] [Indexed: 12/18/2022] Open
Abstract
Adult T-cell Leukemia (ATL) is a lymphoproliferative disease of CD4+ T-cells infected with Human T-cell Leukemia Virus type I (HTLV-1). With the exception of allogeneic hematopoietic stem cell transplantation, there are no effective treatments to cure ATL, and ATL cells often acquire resistance to conventional chemotherapeutic agents. Accumulating evidence shows that development and maintenance of ATL requires key contributions from the viral protein, HTLV-1 basic leucine zipper factor (HBZ). In this study we found that HBZ activates expression of Heme Oxygenase 1 (HMOX-1), a component of the oxidative stress response that functions to detoxify free heme. Transcription of HMOX1 and other antioxidant genes is regulated by the small Mafs. These cellular basic leucine zipper (bZIP) factors control transcription by forming homo- or heterodimers among themselves or with other cellular bZIP factors that then bind Maf responsive elements (MAREs) in promoters or enhancers of antioxidant genes. Our data support a model in which HBZ activates HMOX1 transcription by forming heterodimers with the small Mafs that bind MAREs located in an upstream enhancer region. Consistent with this model, we found that HMOX-1 is upregulated in HTLV-1-transformed T-cell lines and confers these cells with resistance to heme-induced cytotoxicity. In this context, HBZ-mediated activation of HMOX-1 expression may contribute to resistance of ATL cells to certain chemotherapeutic agents. We also provide evidence that HBZ counteracts oxidative stress caused by two other HTLV-1-encoded proteins, Tax and p13. Tax induces oxidative stress as a byproduct of driving mitotic expansion of infected cells, and p13 is believed to induce oxidative stress to eliminate infected cells that have become transformed. Therefore, in this context, HBZ-mediated activation of HMOX-1 expression may facilitate transformation. Overall, this study characterizes a novel function of HBZ that may support the development and maintenance of ATL.
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Affiliation(s)
- Amanda W. Rushing
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, United States of America
- * E-mail: (AWR); (IL)
| | - Blake Rushing
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, United States of America
| | - Kimson Hoang
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, United States of America
| | - Stephanie V. Sanders
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, United States of America
| | - Jean-Marie Péloponèse
- Institut de Recherche en Infectiologie de Montpellier, Centre National de la Recherche Scientifique, Université de Montpellier, Montpellier, France
| | - Nicholas Polakowski
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, United States of America
| | - Isabelle Lemasson
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, United States of America
- * E-mail: (AWR); (IL)
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Fochi S, Bergamo E, Serena M, Mutascio S, Journo C, Mahieux R, Ciminale V, Bertazzoni U, Zipeto D, Romanelli MG. TRAF3 Is Required for NF-κB Pathway Activation Mediated by HTLV Tax Proteins. Front Microbiol 2019; 10:1302. [PMID: 31244811 PMCID: PMC6581700 DOI: 10.3389/fmicb.2019.01302] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 05/24/2019] [Indexed: 01/23/2023] Open
Abstract
Human T-cell leukemia viruses type 1 (HTLV-1) and type 2 (HTLV-2) share a common genome organization and expression strategy but have distinct pathological properties. HTLV-1 is the etiological agent of Adult T-cell Leukemia (ATL) and of HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP), whereas HTLV-2 does not cause hematological disorders and is only sporadically associated with cases of subacute myelopathy. Both HTLV genomes encode two regulatory proteins that play a pivotal role in pathogenesis: the transactivating Tax-1 and Tax-2 proteins and the antisense proteins HBZ and APH-2, respectively. We recently reported that Tax-1 and Tax-2 form complexes with the TNF-receptor associated factor 3, TRAF3, a negative regulator of the non-canonical NF-κB pathway. The NF-κB pathway is constitutively activated by the Tax proteins, whereas it is inhibited by HBZ and APH-2. The antagonistic effects of Tax and antisense proteins on NF-κB activation have not yet been fully clarified. Here, we investigated the effect of TRAF3 interaction with HTLV regulatory proteins and in particular its consequence on the subcellular distribution of the effector p65/RelA protein. We demonstrated that Tax-1 and Tax-2 efficiency on NF-κB activation is impaired in TRAF3 deficient cells obtained by CRISPR/Cas9 editing. We also found that APH-2 is more effective than HBZ in preventing Tax-dependent NF-κB activation. We further observed that TRAF3 co-localizes with Tax-2 and APH-2 in cytoplasmic complexes together with NF-κB essential modulator NEMO and TAB2, differently from HBZ and TRAF3. These results contribute to untangle the mechanism of NF-κB inhibition by HBZ and APH-2, highlighting the different role of the HTLV-1 and HTLV-2 regulatory proteins in the NF-κB activation.
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Affiliation(s)
- Stefania Fochi
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biology and Genetics, University of Verona, Verona, Italy
| | - Elisa Bergamo
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biology and Genetics, University of Verona, Verona, Italy
| | - Michela Serena
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biology and Genetics, University of Verona, Verona, Italy
| | - Simona Mutascio
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biology and Genetics, University of Verona, Verona, Italy
| | - Chloé Journo
- Retroviral Oncogenesis Laboratory, Centre International de Recherche en Infectiologie (CIRI), INSERM U1111 - Université Claude Bernard Lyon 1, CNRS, Equipe Labellisée "Fondation pour la Recherche Médicale", UMR5308, Ecole Normale Supérieure de Lyon, Université Lyon, Lyon, France
| | - Renaud Mahieux
- Retroviral Oncogenesis Laboratory, Centre International de Recherche en Infectiologie (CIRI), INSERM U1111 - Université Claude Bernard Lyon 1, CNRS, Equipe Labellisée "Fondation pour la Recherche Médicale", UMR5308, Ecole Normale Supérieure de Lyon, Université Lyon, Lyon, France
| | - Vincenzo Ciminale
- Department of Surgery, Oncology and Gastroenterology, University of Padua, Padua, Italy.,Veneto Institute of Oncology IOV - IRCCS, Padua, Italy
| | - Umberto Bertazzoni
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biology and Genetics, University of Verona, Verona, Italy
| | - Donato Zipeto
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biology and Genetics, University of Verona, Verona, Italy
| | - Maria Grazia Romanelli
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biology and Genetics, University of Verona, Verona, Italy
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Zhang L, Zhao J, Gurkar A, Niedernhofer LJ, Robbins PD. Methods to Quantify the NF-κB Pathway During Senescence. Methods Mol Biol 2019; 1896:231-250. [PMID: 30474851 DOI: 10.1007/978-1-4939-8931-7_18] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Nuclear factor κB (NF-κB) is a family of transcription factors important for regulating innate and adaptive immunity, cellular proliferation, apoptosis and senescence. The NF-κB family is comprised of five subunits, RelA/p65, RelB, C-Rel, p50 (p105/NF-κB1), and p52 (p100/NF-κB2). NF-κB activity goes up with age in multiple tissues. The two subunits RelA/p65 and p50 have been implicated in senescence and aging with genetic deletion of p65 and p50 reducing or increasing senescence respectively. Pharmacologic inhibition of NF-κB also extends health span and reduces senescence in mouse models of accelerated aging. In addition, NF-κB regulates expression of many of senescence associated secretory phenotype (SASP) factors released by certain types of senescent cells that drives loss of tissue homeostasis and secondary senescence. To measure NF-κB activity with aging in vivo, multiple methods can and need to be utilized including cellular localization of p65, EMSA analysis of NF-κB DNA binding, RNA in situ hybridization, and analysis of expression of NF-κB target genes. To colocalize NF-κB activation and senescence, p65 localization or transcriptional activity can be measured by immunostaining or RNA in situ hybridization for NF-κB regulated genes along with methods such as immunostaining for γH2AX or RNA in situ for senescence markers like p16INK4a and p21. These and related methods will be described in this chapter.
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Affiliation(s)
- Lei Zhang
- Department of Molecular Medicine and Center on Aging, The Scripps Research Institute, Jupiter, FL, USA
| | - Jing Zhao
- Department of Molecular Medicine and Center on Aging, The Scripps Research Institute, Jupiter, FL, USA
- Disease Biology and Cellular Pharmacology, Recursion Pharmaceuticals, Salt Lake, UT, USA
| | - Aditi Gurkar
- Department of Molecular Medicine and Center on Aging, The Scripps Research Institute, Jupiter, FL, USA
- Aging Institute, Division of Geriatric Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Laura J Niedernhofer
- Department of Molecular Medicine and Center on Aging, The Scripps Research Institute, Jupiter, FL, USA
| | - Paul D Robbins
- Department of Molecular Medicine and Center on Aging, The Scripps Research Institute, Jupiter, FL, USA.
- Department of Biochemistry, Molecular Biology and Biophysics, Institute on the Biology of Aging and Metabolism, University of Minnesota, Minneapolis, MN, USA.
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Zhang L, Yousefzadeh MJ, Suh Y, Niedernhofer LJ, Robbins PD. Signal Transduction, Ageing and Disease. Subcell Biochem 2019; 91:227-247. [PMID: 30888655 DOI: 10.1007/978-981-13-3681-2_9] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Ageing is defined by the loss of functional reserve over time, leading to a decreased tissue homeostasis and increased age-related pathology. The accumulation of damage including DNA damage contributes to driving cell signaling pathways that, in turn, can drive different cell fates, including senescence and apoptosis, as well as mitochondrial dysfunction and inflammation. In addition, the accumulation of cell autonomous damage with time also drives ageing through non-cell autonomous pathways by modulation of signaling pathways. Interestingly, genetic and pharmacologic analysis of factors able to modulate lifespan and healthspan in model organisms and even humans have identified several key signaling pathways including IGF-1, NF-κB, FOXO3, mTOR, Nrf-2 and sirtuins. This review will discuss the roles of several of these key signaling pathways, in particular NF-κB and Nrf2, in modulating ageing and age-related diseases.
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Affiliation(s)
- Lei Zhang
- Institute on the Biology of Aging and Metabolism and Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Matthew J Yousefzadeh
- Institute on the Biology of Aging and Metabolism and Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Yousin Suh
- Departments of Genetics and Medicine and the Institute for Ageing Research, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Laura J Niedernhofer
- Institute on the Biology of Aging and Metabolism and Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Paul D Robbins
- Institute on the Biology of Aging and Metabolism and Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA.
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48
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O'Reilly LA, Putoczki TL, Mielke LA, Low JT, Lin A, Preaudet A, Herold MJ, Yaprianto K, Tai L, Kueh A, Pacini G, Ferrero RL, Gugasyan R, Hu Y, Christie M, Wilcox S, Grumont R, Griffin MDW, O'Connor L, Smyth GK, Ernst M, Waring P, Gerondakis S, Strasser A. Loss of NF-κB1 Causes Gastric Cancer with Aberrant Inflammation and Expression of Immune Checkpoint Regulators in a STAT-1-Dependent Manner. Immunity 2018; 48:570-583.e8. [PMID: 29562203 DOI: 10.1016/j.immuni.2018.03.003] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 12/04/2017] [Accepted: 02/28/2018] [Indexed: 12/13/2022]
Abstract
Polymorphisms in NFKB1 that diminish its expression have been linked to human inflammatory diseases and increased risk for epithelial cancers. The underlying mechanisms are unknown, and the link is perplexing given that NF-κB signaling reportedly typically exerts pro-tumorigenic activity. Here we have shown that NF-κB1 deficiency, even loss of a single allele, resulted in spontaneous invasive gastric cancer (GC) in mice that mirrored the histopathological progression of human intestinal-type gastric adenocarcinoma. Bone marrow chimeras revealed that NF-κB1 exerted tumor suppressive functions in both epithelial and hematopoietic cells. RNA-seq analysis showed that NF-κB1 deficiency resulted in aberrant JAK-STAT signaling, which dysregulated expression of effectors of inflammation, antigen presentation, and immune checkpoints. Concomitant loss of STAT1 prevented these immune abnormalities and GC development. These findings provide mechanistic insight into how polymorphisms that attenuate NFKB1 expression predispose humans to epithelial cancers, highlighting the pro-tumorigenic activity of STAT1 and identifying targetable vulnerabilities in GC.
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Affiliation(s)
- Lorraine A O'Reilly
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Tracy L Putoczki
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Lisa A Mielke
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Jun T Low
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Ann Lin
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Adele Preaudet
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Marco J Herold
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Kelvin Yaprianto
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria 3010, Australia; Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Lin Tai
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Andrew Kueh
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Guido Pacini
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Richard L Ferrero
- Hudson Institute of Medical Research, Clayton, Victoria 3168, Australia
| | - Raffi Gugasyan
- Healthy Ageing, Life Sciences Discipline, The Burnet Institute, Melbourne, Victoria 3004, Australia; Central Clinical School, Monash University, Melbourne, Victoria 3004, Australia
| | - Yifang Hu
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia
| | - Michael Christie
- Centre for Translational Pathology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Stephen Wilcox
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Raelene Grumont
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia; Cancer Program, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Victoria, Australia
| | - Michael D W Griffin
- Department of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Victoria, 3010, Australia; Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Liam O'Connor
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Gordon K Smyth
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Mathematics and Statistics, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Mathias Ernst
- Olivia Newton-John Cancer Research Institute and La Trobe University School of Cancer Medicine, Heidelberg, Victoria 3084, Australia
| | - Paul Waring
- Department of Pathology, The University of Melbourne, Parkville 3052, Victoria, Australia
| | - Steve Gerondakis
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria 3800, Australia; Cancer Program, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Victoria, Australia
| | - Andreas Strasser
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria 3052, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria 3010, Australia.
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Hutchison T, Malu A, Yapindi L, Bergeson R, Peck K, Romeo M, Harrod C, Pope J, Smitherman L, Gwinn W, Ratner L, Yates C, Harrod R. The TP53-Induced Glycolysis and Apoptosis Regulator mediates cooperation between HTLV-1 p30 II and the retroviral oncoproteins Tax and HBZ and is highly expressed in an in vivo xenograft model of HTLV-1-induced lymphoma. Virology 2018; 520:39-58. [PMID: 29777913 DOI: 10.1016/j.virol.2018.05.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 05/08/2018] [Accepted: 05/10/2018] [Indexed: 12/28/2022]
Abstract
The human T-cell leukemia virus type-1 (HTLV-1) is an oncoretrovirus that infects and transforms CD4+ T-cells and causes adult T-cell leukemia/lymphoma (ATLL) -an aggressive lymphoproliferative disease that is highly refractive to most anticancer therapies. The HTLV-1 proviral genome encodes several regulatory products within a conserved 3' nucleotide sequence, known as pX; however, it remains unclear how these factors might cooperate or dynamically interact in virus-infected cells. Here we demonstrate that the HTLV-1 latency-maintenance factor p30II induces the TP53-induced glycolysis and apoptosis regulator (TIGAR) and counters the oxidative stress, mitochondrial damage, and cytotoxicity caused by the viral oncoproteins Tax and HBZ. The p30II protein cooperates with Tax and HBZ and enhances their oncogenic potential in colony transformation/foci-formation assays. Further, we have shown that TIGAR is highly expressed in HTLV-1-induced tumors associated with oncogene dysregulation and increased angiogenesis in an in vivo xenograft model of HTLV-1-induced T-cell lymphoma. These findings provide the first evidence that p30II likely collaborates as an ancillary factor for the major oncoproteins Tax and HBZ during retroviral carcinogenesis.
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Affiliation(s)
- Tetiana Hutchison
- Laboratory of Molecular Virology, Department of Biological Sciences, and The Dedman College Center for Drug Discovery, Design & Delivery, Southern Methodist University, 6501 Airline Drive, 334-DLS, Dallas, TX 75275-0376, United States
| | - Aditi Malu
- Laboratory of Molecular Virology, Department of Biological Sciences, and The Dedman College Center for Drug Discovery, Design & Delivery, Southern Methodist University, 6501 Airline Drive, 334-DLS, Dallas, TX 75275-0376, United States
| | - Laçin Yapindi
- Laboratory of Molecular Virology, Department of Biological Sciences, and The Dedman College Center for Drug Discovery, Design & Delivery, Southern Methodist University, 6501 Airline Drive, 334-DLS, Dallas, TX 75275-0376, United States
| | - Rachel Bergeson
- Laboratory of Molecular Virology, Department of Biological Sciences, and The Dedman College Center for Drug Discovery, Design & Delivery, Southern Methodist University, 6501 Airline Drive, 334-DLS, Dallas, TX 75275-0376, United States
| | - Kendra Peck
- Laboratory of Molecular Virology, Department of Biological Sciences, and The Dedman College Center for Drug Discovery, Design & Delivery, Southern Methodist University, 6501 Airline Drive, 334-DLS, Dallas, TX 75275-0376, United States
| | - Megan Romeo
- Laboratory of Molecular Virology, Department of Biological Sciences, and The Dedman College Center for Drug Discovery, Design & Delivery, Southern Methodist University, 6501 Airline Drive, 334-DLS, Dallas, TX 75275-0376, United States
| | - Carolyn Harrod
- Laboratory of Molecular Virology, Department of Biological Sciences, and The Dedman College Center for Drug Discovery, Design & Delivery, Southern Methodist University, 6501 Airline Drive, 334-DLS, Dallas, TX 75275-0376, United States
| | - Jordan Pope
- Laboratory of Molecular Virology, Department of Biological Sciences, and The Dedman College Center for Drug Discovery, Design & Delivery, Southern Methodist University, 6501 Airline Drive, 334-DLS, Dallas, TX 75275-0376, United States
| | - Louisa Smitherman
- Laboratory of Molecular Virology, Department of Biological Sciences, and The Dedman College Center for Drug Discovery, Design & Delivery, Southern Methodist University, 6501 Airline Drive, 334-DLS, Dallas, TX 75275-0376, United States
| | - Wesleigh Gwinn
- Laboratory of Molecular Virology, Department of Biological Sciences, and The Dedman College Center for Drug Discovery, Design & Delivery, Southern Methodist University, 6501 Airline Drive, 334-DLS, Dallas, TX 75275-0376, United States
| | - Lee Ratner
- Departments of Medicine and Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, United States
| | - Courtney Yates
- Laboratory Animal Resource Center, Southern Methodist University, Dallas, TX 75275, United States
| | - Robert Harrod
- Laboratory of Molecular Virology, Department of Biological Sciences, and The Dedman College Center for Drug Discovery, Design & Delivery, Southern Methodist University, 6501 Airline Drive, 334-DLS, Dallas, TX 75275-0376, United States.
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50
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Harhaj EW, Giam CZ. NF-κB signaling mechanisms in HTLV-1-induced adult T-cell leukemia/lymphoma. FEBS J 2018; 285:3324-3336. [PMID: 29722927 DOI: 10.1111/febs.14492] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 04/12/2018] [Accepted: 04/26/2018] [Indexed: 12/27/2022]
Abstract
The human T-cell leukemia virus type 1 (HTLV-1) is a complex deltaretrovirus linked to adult T-cell leukemia/lymphoma (ATLL), a fatal CD4 + malignancy in 3-5% of infected individuals. The HTLV-1 Tax regulatory protein plays indispensable roles in regulating viral gene expression and activating cellular signaling pathways that drive the proliferation and clonal expansion of T cells bearing HTLV-1 proviral integrations. Tax is a potent activator of NF-κB, a key signaling pathway that is essential for the survival and proliferation of HTLV-1-infected T cells. However, constitutive NF-κB activation by Tax also triggers a senescence response, suggesting the possibility that only T cells capable of overcoming NF-κB-induced senescence can selectively undergo clonal expansion after HTLV-1 infection. Tax expression is often silenced in the majority of ATLL due to genetic alterations in the tax gene or DNA hypermethylation of the 5'-LTR. Despite the loss of Tax, NF-κB activation remains persistently activated in ATLL due to somatic mutations in genes in the T/B-cell receptor (T/BCR) and NF-κB signaling pathways. In this review, we focus on the key events driving Tax-dependent and -independent mechanisms of NF-κB activation during the multistep process leading to ATLL.
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Affiliation(s)
- Edward William Harhaj
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Chou-Zen Giam
- Department of Microbiology and Immunology, Uniformed Services University, Bethesda, MD, USA
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