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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:e0040524. [PMID: 38874362 DOI: 10.1128/jvi.00405-24] [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: 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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De Mel S, Lee AR, Tan JHI, Tan RZY, Poon LM, Chan E, Lee J, Chee YL, Lakshminarasappa SR, Jaynes PW, Jeyasekharan AD. Targeting the DNA damage response in hematological malignancies. Front Oncol 2024; 14:1307839. [PMID: 38347838 PMCID: PMC10859481 DOI: 10.3389/fonc.2024.1307839] [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: 10/05/2023] [Accepted: 01/03/2024] [Indexed: 02/15/2024] Open
Abstract
Deregulation of the DNA damage response (DDR) plays a critical role in the pathogenesis and progression of many cancers. The dependency of certain cancers on DDR pathways has enabled exploitation of such through synthetically lethal relationships e.g., Poly ADP-Ribose Polymerase (PARP) inhibitors for BRCA deficient ovarian cancers. Though lagging behind that of solid cancers, DDR inhibitors (DDRi) are being clinically developed for haematological cancers. Furthermore, a high proliferative index characterize many such cancers, suggesting a rationale for combinatorial strategies targeting DDR and replicative stress. In this review, we summarize pre-clinical and clinical data on DDR inhibition in haematological malignancies and highlight distinct haematological cancer subtypes with activity of DDR agents as single agents or in combination with chemotherapeutics and targeted agents. We aim to provide a framework to guide the design of future clinical trials involving haematological cancers for this important class of drugs.
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Affiliation(s)
- Sanjay De Mel
- Department of Haematology-Oncology, National University Cancer Institute, Singapore, National University Health System, Singapore, Singapore
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- NUS Center for Cancer Research (N2CR), Yong Loo Lin School of Medicine, National University Singapore, Singapore, Singapore
| | - Ainsley Ryan Lee
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Joelle Hwee Inn Tan
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Rachel Zi Yi Tan
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Li Mei Poon
- Department of Haematology-Oncology, National University Cancer Institute, Singapore, National University Health System, Singapore, Singapore
- NUS Center for Cancer Research (N2CR), Yong Loo Lin School of Medicine, National University Singapore, Singapore, Singapore
| | - Esther Chan
- Department of Haematology-Oncology, National University Cancer Institute, Singapore, National University Health System, Singapore, Singapore
- NUS Center for Cancer Research (N2CR), Yong Loo Lin School of Medicine, National University Singapore, Singapore, Singapore
| | - Joanne Lee
- Department of Haematology-Oncology, National University Cancer Institute, Singapore, National University Health System, Singapore, Singapore
- NUS Center for Cancer Research (N2CR), Yong Loo Lin School of Medicine, National University Singapore, Singapore, Singapore
| | - Yen Lin Chee
- Department of Haematology-Oncology, National University Cancer Institute, Singapore, National University Health System, Singapore, Singapore
- NUS Center for Cancer Research (N2CR), Yong Loo Lin School of Medicine, National University Singapore, Singapore, Singapore
| | - Satish R. Lakshminarasappa
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Patrick William Jaynes
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
| | - Anand D. Jeyasekharan
- Department of Haematology-Oncology, National University Cancer Institute, Singapore, National University Health System, Singapore, Singapore
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- NUS Center for Cancer Research (N2CR), Yong Loo Lin School of Medicine, National University Singapore, Singapore, Singapore
- Cancer Science Institute of Singapore, National University of Singapore, Singapore, Singapore
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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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Niazmand S, Gowhari Shabgah A, Hosseinian S, Gholizadeh Navashenaq J, Kamali A, Khazdair MR, Baghcheghi Y, Hedayati‐Moghadam M. The effect of HTLV1 infection on inflammatory and oxidative parameters in the liver, kidney, and pancreases of BALB/c mice. Physiol Rep 2022; 10:e15243. [PMID: 35373925 PMCID: PMC8978595 DOI: 10.14814/phy2.15243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 01/05/2022] [Accepted: 02/13/2022] [Indexed: 12/04/2022] Open
Abstract
Viral infections are linked to the progression of inflammatory reactions and oxidative stress that play pivotal roles in systemic diseases. To confirm this phenomenon, in the present study, TNF‐α level and oxidative stress markers were examined in the liver, kidney, and pancreas of HTLV1‐infected male BALB/c mice. To this end, twenty BALB/c mice were divided into HTLV1‐infected mice that were inoculated with 1‐million HTLV1‐infected cells (MT‐2), and the control groups. Two months after inoculation, the peripheral blood, mesenteric lymph nodes, liver, kidney, and pancreas were collected after deep anesthetization of mice (ketamine, 30 mg/kg). The extracted DNA of mesenteric lymph nodes was obtained to quantify proviral load (PVL) using quantitative real‐time polymerase chain reaction (qRT‐PCR). The levels of lipid peroxidation, total thiol (SH), nitric oxide (NO), TNF‐α, catalase (CAT), and superoxide dismutase (SOD) activities were examined in the liver, kidney, and pancreases. Furthermore, histopathological changes in the liver and kidney were evaluated. In liver tissue, the levels of MDA, TNF‐α, and blood cell infiltration were significantly increased, and the levels of CAT and SOD were significantly decreased. In the kidney, a reduction in SOD, CAT, and total SH and an increase in MDA and NO were observed. In the pancreas, CAT activity, total SH, and SOD were decreased, and the levels of MDA and NO were enhanced. In terms of TNF‐α production, it has been shown that the level of this inflammatory cytokine was increased in the liver, kidney, and pancreas. The HTLV1 may have a role in inducing inflammatory reactions and oxidative stress pathways in the tissues.
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Affiliation(s)
- Saeed Niazmand
- Department of Physiology Faculty of Medicine Mashhad University of Medical Sciences Mashhad Iran
| | | | - Sara Hosseinian
- Department of Physiology Faculty of Medicine Mashhad University of Medical Sciences Mashhad Iran
| | | | - Ali Kamali
- Department of Infectious Diseases School of Medicine Jiroft University of Medical Sciences Jiroft Iran
| | - Mohammad Reza Khazdair
- Cardiovascular Diseases Research Center Birjand University of Medical Science Birjand Iran
| | - Yousef Baghcheghi
- Student Research Committee Jiroft University of Medical Sciences Jiroft Iran
| | - Mahdiyeh Hedayati‐Moghadam
- Student Research Committee Jiroft University of Medical Sciences Jiroft Iran
- Department of Physiology School of Medicine Jiroft University of Medical Sciences Jiroft Iran
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5
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Bellon M, Bialuk I, Galli V, Bai XT, Farre L, Bittencourt A, Marçais A, Petrus MN, Ratner L, Waldmann TA, Asnafi V, Gessain A, Matsuoka M, Franchini G, Hermine O, Watanabe T, Nicot C. Germinal epimutation of Fragile Histidine Triad (FHIT) gene is associated with progression to acute and chronic adult T-cell leukemia diseases. Mol Cancer 2021; 20:86. [PMID: 34092254 PMCID: PMC8183032 DOI: 10.1186/s12943-021-01370-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 05/12/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Human T cell Leukemia virus type 1 (HTLV-I) is etiologically linked to adult T cell leukemia/lymphoma (ATL) and an inflammatory neurodegenerative disease called HTLV-I-associated myelopathy or tropical spastic paraparesis (HAM/TSP). The exact genetic or epigenetic events and/or environmental factors that influence the development of ATL, or HAM/TSP diseases are largely unknown. The tumor suppressor gene, Fragile Histidine Triad Diadenosine Triphosphatase (FHIT), is frequently lost in cancer through epigenetic modifications and/or deletion. FHIT is a tumor suppressor acting as genome caretaker by regulating cellular DNA repair. Indeed, FHIT loss leads to replicative stress and accumulation of double DNA strand breaks. Therefore, loss of FHIT expression plays a key role in cellular transformation. METHODS Here, we studied over 400 samples from HTLV-I-infected individuals with ATL, TSP/HAM, or asymptomatic carriers (AC) for FHIT loss and expression. We examined the epigenetic status of FHIT through methylation specific PCR and bisulfite sequencing; and correlated these results to FHIT expression in patient samples. RESULTS We found that epigenetic alteration of FHIT is specifically found in chronic and acute ATL but is absent in asymptomatic HTLV-I carriers and TSP/HAM patients' samples. Furthermore, the extent of FHIT methylation in ATL patients was quantitatively comparable in virus-infected and virus non-infected cells. We also found that longitudinal HTLV-I carriers that progressed to smoldering ATL and descendants of ATL patients harbor FHIT methylation. CONCLUSIONS These results suggest that germinal epigenetic mutation of FHIT represents a preexisting mark predisposing to the development of ATL diseases. These findings have important clinical implications as patients with acute ATL are rarely cured. Our study suggests an alternative strategy to the current "wait and see approach" in that early screening of HTLV-I-infected individuals for germinal epimutation of FHIT and early treatment may offer significant clinical benefits.
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Affiliation(s)
- Marcia Bellon
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, KS, 66160, USA
| | - Izabela Bialuk
- Animal Models and Retroviral Vaccines Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Veronica Galli
- Animal Models and Retroviral Vaccines Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Xue-Tao Bai
- Comprehensive Cancer Center, Department of Health Sciences, Ohio State University, Columbus, OH, USA
| | - Lourdes Farre
- Program in Molecular Mechanisms and Experimental Therapy in Oncology, IDIBELL, Hospitalet de Llobregat, Barcelona, Spain
| | - Achilea Bittencourt
- Department of Pathology, Prof. Edgard Santos Teaching Hospital, Federal University of Bahia, Salvador, Bahia, Brazil
| | - Ambroise Marçais
- Institut Necker-Enfants Malades, Institut National de la Santé et de la Recherche Médicale U1151, Laboratoire Onco-Hématologie, Paris, France
| | - Michael N Petrus
- Lymphoid Malignancies Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Lee Ratner
- Division of Oncology, Department of Medicine, Washington University, St Louis, MO, USA
| | - Thomas A Waldmann
- Lymphoid Malignancies Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Vahid Asnafi
- Université de Paris (Descartes), Institut Necker-Enfants Malades, Institut National de la Santé et de la Recherche Médicale (INSERM) U1151 Laboratoire Onco-Hematology, Paris, France
| | - Antoine Gessain
- Unité d'épidémiologie et de Physiopathologie des virus Oncogene, Institut Pasteur, 75015, Paris, France.,Centre National de la Recherche Scientifique (CNRS) UMR 3569, 75015, Paris, France
| | - Masao Matsuoka
- Laboratory of Virus Control, Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan.,Department of Hematology, Rheumatology, and Infectious Disease, Graduate School of Medical Sciences, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Genoveffa Franchini
- Animal Models and Retroviral Vaccines Section, Vaccine Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Olivier Hermine
- Institut Necker-Enfants Malades, Institut National de la Santé et de la Recherche Médicale U1151, Laboratoire Onco-Hématologie, Paris, France
| | - Toshiki Watanabe
- Department of Hematology/Oncology, IMSUT Hospital, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Christophe Nicot
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, KS, 66160, USA.
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Tanaka M, Tanaka K, Ida C, Oue A, Yamashita S, Yao J, Takenouchi N, Miwa M. Conflicting effects of poly(ADP-ribose) polymerase inhibitor on cell-mediated and virion-mediated HTLV-1 infection. Virus Res 2019; 270:197653. [PMID: 31299194 DOI: 10.1016/j.virusres.2019.197653] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 04/16/2019] [Accepted: 07/08/2019] [Indexed: 11/18/2022]
Abstract
Adult T-cell leukemia and human T-cell leukemia virus type 1 (HTLV-1) - associated myelopathy/tropical spastic paraparesis, which develop after HTLV-1 infection, are difficult to cure. In particular, the mode of HTLV-1 propagation is not well understood. Poly (ADP-ribose) polymerase-1 is reported to be a co-activator of HTLV-1 Tax protein; however, the effects of polyADP-ribosylation on infectivity of HTLV-1 have not been fully clarified. We studied the effects of a PARP inhibitor on two modes of HTLV-1 transmission: through cell adhesion between MT-2 cells (an HTLV-1-infected cell line) and uninfected cells and through virus particles produced by HTLV-1-producing c77 cells. Although the PARP inhibitor decreased HTLV-1 infection through cell adhesion, it increased HTLV-1 infection through virion production and caused apoptosis of HTLV-1-infected cells. Thus, careful consideration is required for clinical application of PARP inhibitors in HTLV-1 patients.
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Affiliation(s)
- Masakazu Tanaka
- Department of Microbiology, Kansai Medical University, Hirakata, Osaka, 573-1010, Japan; Division of Neuroimmunology, Joint Research Center for Human Retrovirus Infection, Kagoshima University, Kagoshima, Kagoshima 890-8544, Japan.
| | - Koji Tanaka
- Department of Microbiology, Kansai Medical University, Hirakata, Osaka, 573-1010, Japan; Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, 526-0829, Japan
| | - Chieri Ida
- Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, 526-0829, Japan; College of Nagoya Women's University, Nagoya, Aichi, 467-8610, Japan
| | - Atsushi Oue
- Gunma University Graduate School of Medicine, Maebashi, Gunma, 371-8511, Japan
| | - Sachiko Yamashita
- Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, 526-0829, Japan
| | - Jinchun Yao
- Department of Microbiology, Kansai Medical University, Hirakata, Osaka, 573-1010, Japan
| | - Norihiro Takenouchi
- Department of Microbiology, Kansai Medical University, Hirakata, Osaka, 573-1010, Japan
| | - Masanao Miwa
- Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga, 526-0829, Japan; Institute of Basic Medical Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8575, Japan
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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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8
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Molecular targeting for treatment of human T-lymphotropic virus type 1 infection. Biomed Pharmacother 2019; 109:770-778. [DOI: 10.1016/j.biopha.2018.10.139] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 10/22/2018] [Accepted: 10/24/2018] [Indexed: 12/13/2022] Open
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Marino-Merlo F, Mastino A, Grelli S, Hermine O, Bazarbachi A, Macchi B. Future Perspectives on Drug Targeting in Adult T Cell Leukemia-Lymphoma. Front Microbiol 2018; 9:925. [PMID: 29867836 PMCID: PMC5954109 DOI: 10.3389/fmicb.2018.00925] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 04/20/2018] [Indexed: 12/02/2022] Open
Abstract
Human T cell leukemia virus type 1 (HTLV-1) is the etiological agent of adult T cell leukemia/lymphoma (ATL), HTLV-1 associated myelopathy (HAM/TSP), and of a number of inflammatory diseases with an estimated 10–20 million infected individuals worldwide. Despite a number of therapeutic approaches, a cure for ATL is still in its infancy. Conventional chemotherapy has short-term efficacy, particularly in the acute subtype. Allogeneic stem cell transplantation offers long-term disease control to around one third of transplanted patients, but few can reach to transplant. This prompted, over the past recent years, the conduction of a number of clinical trials using novel treatments. Meanwhile, new data have been accumulated on biological and molecular bases of HTLV-1 transforming and infecting activity. These data offer new rational for targeted therapies of ATL. Taking into account the double-face of ATL as an hematologic malignancy as well as a viral infectious disease, this Mini-Review seeks to provide an up-to-date overview of recent efforts in the understanding of the mechanisms involved in already used therapeutic regimens showing promising results, and in selecting novel drug targets for ATL.
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Affiliation(s)
| | - Antonio Mastino
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Messina, Italy.,Institute of Translational Pharmacology, The National Research Council, Rome, Italy
| | - Sandro Grelli
- Department of Experimental Medicine and Surgery, University of Rome "Tor Vergata", Rome, Italy
| | - Olivier Hermine
- INSERM U1163, CNRS ERL 8654, Department of Hematology, Imagine Institute, Hôpital Necker-Enfants Malades, Paris, France
| | - Ali Bazarbachi
- Department of Internal Medicine, American University of Beirut, Beirut, Lebanon.,Department of Anatomy, Cell Biology and Physiological Sciences, American University of Beirut, Beirut, Lebanon
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Kotsantis P, Petermann E, Boulton SJ. Mechanisms of Oncogene-Induced Replication Stress: Jigsaw Falling into Place. Cancer Discov 2018; 8:537-555. [PMID: 29653955 DOI: 10.1158/2159-8290.cd-17-1461] [Citation(s) in RCA: 232] [Impact Index Per Article: 38.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 02/26/2018] [Accepted: 03/09/2018] [Indexed: 12/31/2022]
Abstract
Oncogene activation disturbs cellular processes and accommodates a complex landscape of changes in the genome that contribute to genomic instability, which accelerates mutation rates and promotes tumorigenesis. Part of this cellular turmoil involves deregulation of physiologic DNA replication, widely described as replication stress. Oncogene-induced replication stress is an early driver of genomic instability and is attributed to a plethora of factors, most notably aberrant origin firing, replication-transcription collisions, reactive oxygen species, and defective nucleotide metabolism.Significance: Replication stress is a fundamental step and an early driver of tumorigenesis and has been associated with many activated oncogenes. Deciphering the mechanisms that contribute to the replication stress response may provide new avenues for targeted cancer treatment. In this review, we discuss the latest findings on the DNA replication stress response and examine the various mechanisms through which activated oncogenes induce replication stress. Cancer Discov; 8(5); 537-55. ©2018 AACR.
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Affiliation(s)
| | - Eva Petermann
- Institute of Cancer and Genomic Sciences, University of Birmingham, Edgbaston, Birmingham, United Kingdom
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11
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Bai XT, Yeh CH, Nicot C. NOTCH1 Activation Depletes the Pool of Side Population Stem Cells in ATL. ACTA ACUST UNITED AC 2017; 4. [PMID: 28920078 PMCID: PMC5596512 DOI: 10.13188/2377-9292.1000013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
BACKGROUND HTLV-I infection is associated with the development of adult T-cell leukemia (ATL), a malignancy characterized by a high rate of disease relapse and poor survival. Previous studies reported the existence of side population (SP) cells in HTLV-I Tax transgenic mouse models. These studies showed that these ATL-like derived SP cells have both self-renewal and leukemia renewal capacity and represent Cancer Stem Cells (CSC)/Leukemia-Initiating Cells (LIC). Since CSC/LIC are resistant to conventional therapies, a better characterization is needed. METHODS We isolated, sorted and characterized SP cells from uncultured PBMCs from ATL patients and from ATL patient-derived cell lines. We then identified several specific signaling pathways activated or suppressed in these cells. Expression of viral gene HBZ and Tax transcriptional activity was also investigated. Using gamma-secretase inhibitor (GSI, Calbiochem) and stably transduced ATL cell lines expressing TET-inducible NOTCH 1 intracellular domain (NICD), we characterized the role of activated NOTCH 1 in the maintenance of the SP cells in ATL. RESULTS Our studies confirm the existence of SP cells in ATL samples. These cells demonstrate lower activation of NOTCH1 and Tax, and reduced expression of STAT3, β-catenin/Wnt3 and viral HBZ. We further show that PI3K and the NOTCH1 signaling pathway have opposite functions, and constitutive activation of NOTCH1 signaling depletes the pool of SP cells in ATL-derived cell lines. CONCLUSIONS Our results suggest that in ATL, a balance between activation of the NOTCH1 and PI3K signaling pathway is the key in the control of SP cells maintenance and may offer therapeutic opportunities.
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Affiliation(s)
- Xue Tao Bai
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, USA
| | - Chien-Hung Yeh
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, USA
| | - Christophe Nicot
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, USA
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12
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Chan CP, Kok KH, Jin DY. Human T-Cell Leukemia Virus Type 1 Infection and Adult T-Cell Leukemia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1018:147-166. [PMID: 29052136 DOI: 10.1007/978-981-10-5765-6_9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) is the first retrovirus discovered to cause adult T-cell leukemia (ATL), a highly aggressive blood cancer. HTLV-1 research in the past 35 years has been most revealing in the mechanisms of viral oncogenesis. HTLV-1 establishes a lifelong persistent infection in CD4+ T lymphocytes. The infection outcome is governed by host immunity. ATL develops in 2-5% of infected individuals 30-50 years after initial exposure. HTLV-1 encodes two oncoproteins Tax and HBZ, which are required for initiation of cellular transformation and maintenance of cell proliferation, respectively. HTLV-1 oncogenesis is driven by a clonal selection and expansion process during which both host and viral factors cooperate to impair genome stability, immune surveillance, and other mechanisms of tumor suppression. A better understanding of HTLV-1 biology and leukemogenesis will reveal new strategies and modalities for ATL prevention and treatment.
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Affiliation(s)
- Chi-Ping Chan
- School of Biomedical Sciences, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong
| | - Kin-Hang Kok
- Department of Microbiology, The University of Hong Kong, 145 Pokfulam Road, Pokfulam, Hong Kong
| | - Dong-Yan Jin
- School of Biomedical Sciences, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong.
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Moles R, Bai XT, Chaib-Mezrag H, Nicot C. WRN-targeted therapy using inhibitors NSC 19630 and NSC 617145 induce apoptosis in HTLV-1-transformed adult T-cell leukemia cells. J Hematol Oncol 2016; 9:121. [PMID: 27829440 PMCID: PMC5103433 DOI: 10.1186/s13045-016-0352-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 11/03/2016] [Indexed: 12/30/2022] Open
Abstract
Background Human T-cell leukemia virus type 1 (HTLV-1) infection is associated with adult T-cell leukemia/lymphoma (ATLL), a lymphoproliferative malignancy with a dismal prognosis and limited therapeutic options. Recent evidence shows that HTLV-1-transformed cells present defects in both DNA replication and DNA repair, suggesting that these cells might be particularly sensitive to treatment with a small helicase inhibitor. Because the “Werner syndrome ATP-dependent helicase” encoded by the WRN gene plays important roles in both cellular proliferation and DNA repair, we hypothesized that inhibition of WRN activity could be used as a new strategy to target ATLL cells. Methods Our analysis demonstrates an apoptotic effect induced by the WRN helicase inhibitor in HTLV-1-transformed cells in vitro and ATL-derived cell lines. Inhibition of cellular proliferation and induction of apoptosis were demonstrated with cell cycle analysis, XTT proliferation assay, clonogenic assay, annexin V staining, and measurement of mitochondrial transmembrane potential. Results Targeted inhibition of the WRN helicase induced cell cycle arrest and apoptosis in HTLV-1-transformed leukemia cells. Treatment with NSC 19630 (WRN inhibitor) induces S-phase cell cycle arrest, disruption of the mitochondrial membrane potential, and decreased expression of anti-apoptotic factor Bcl-2. These events were associated with activation of caspase-3-dependent apoptosis in ATL cells. We identified some ATL cells, ATL-55T and LMY1, less sensitive to NSC 19630 but sensitive to another WRN inhibitor, NSC 617145. Conclusions WRN is essential for survival of ATL cells. Our studies suggest that targeting the WRN helicase with small inhibitors is a novel promising strategy to target HTLV-1-transformed ATL cells.
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Affiliation(s)
- R Moles
- Department of Pathology and Laboratory Medicine, Center for Viral Oncology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS, 66160, USA
| | - X T Bai
- Department of Pathology and Laboratory Medicine, Center for Viral Oncology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS, 66160, USA
| | - H Chaib-Mezrag
- Department of Pathology and Laboratory Medicine, Center for Viral Oncology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS, 66160, USA
| | - C Nicot
- Department of Pathology and Laboratory Medicine, Center for Viral Oncology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS, 66160, USA. .,Department of Pathology and Laboratory Medicine, Center for Viral Oncology, KU Cancer Center, University of Kansas Medical Center, 3901 Rainbow Blvd, Kansas City, KS, 66160, USA.
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Oncogenic mutations in the FBXW7 gene of adult T-cell leukemia patients. Proc Natl Acad Sci U S A 2016; 113:6731-6. [PMID: 27247421 DOI: 10.1073/pnas.1601537113] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-I) is associated with adult T-cell leukemia (ATL), an aggressive lymphoproliferative disease with a dismal prognosis. We have previously described the presence of Notch1 activating mutations and constitutive Notch1 signaling in patients with acute ATL. In this study, we report a high frequency of F-box and WD repeat domain containing 7 (FBXW7)/hCDC4 mutations within the WD40 substrate-binding domain in 8 of 32 acute ATL patients (25%). Functionally, ATL FBXW7 mutants lost their ability to interact with intracellular Notch (NICD), resulting in increased protein stability and constitutive Notch1 signaling. Consistent with the loss-of-function found in ATL patients, expression of WT FBXW7 in several patient-derived ATL lines demonstrated strong tumor-suppressor activity characterized by reduced proliferation of ATL cells. Remarkably, two FBXW7 mutants, D510E and D527G, demonstrated oncogenic activity when expressed in the presence of HTLV-I Tax, mutated p53 R276H, or c-Myc F138C found in human cancers. Transforming activity was further demonstrated by the ability of the FBXW7 D510E mutant to provide IL-2-independent growth of Tax-immortalized human T cells and increase the tumor formation in a xenograft mouse model of ATL. This study suggests that FBXW7, normally a tumor suppressor, can act as an oncogene when mutated and may play an important role in the pathogenesis of ATL.
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Moles R, Bellon M, Nicot C. STAT1: A Novel Target of miR-150 and miR-223 Is Involved in the Proliferation of HTLV-I-Transformed and ATL Cells. Neoplasia 2016; 17:449-62. [PMID: 26025667 PMCID: PMC4468372 DOI: 10.1016/j.neo.2015.04.005] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 04/13/2015] [Accepted: 04/24/2015] [Indexed: 12/20/2022] Open
Abstract
We have previously reported on the deregulation of cellular microRNAs involved in hematopoiesis and inflammation in human T-cell lymphotropic virus type 1 (HTLV-I)–transformed cells. In this study, we demonstrate that miR-150 and miR-223 specifically target the signal transducer and activator of transcription 1 (STAT1) 3′ untranslated region, reducing STAT1 expression and dampening STAT1-dependent signaling in human T cells. The effects of miR-150 and miR-223 on endogenous STAT1 were confirmed using inducible cell lines. Our studies also showed that miR-150 expression is upregulated by interleukin-2 signaling in adult T cell leukemia/lymphoma (ATL) cells. HTLV-I–transformed and ATL-derived cells have reduced levels of miR150 and miR223 expression, which coincide with increased STAT1 expression and STAT1-dependent signaling. Knockdown of STAT1 by short hairpin RNA demonstrated that the constitutive activation of STAT1 is required for the continuous proliferation of HTLV-I–transformed cells. Our studies further demonstrate that increased expression of STAT1 in ATL cells is associated with higher levels of major histocompatibility complex class I expression. Previous studies have demonstrated that the pressure exerted by natural killer (NK) cells in vivo can edit leukemic tumor cells by forcing an increased expression of major histocompatibility complex class I to escape immune clearance. STAT1-expressing tumor cells produce more aggressive tumors because they cannot be eliminated by NK cells. Our results suggest that therapeutic approaches using combined targeting of STAT1 and MHC class I may be an effective approach to activate NK cell–mediated clearance of ATL tumor cells.
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Affiliation(s)
- Ramona Moles
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, KS, USA
| | - Marcia Bellon
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, KS, USA
| | - Christophe Nicot
- Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, KS, USA.
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Yeh CH, Bai XT, Moles R, Ratner L, Waldmann TA, Watanabe T, Toshiki W, Nicot C. Mutation of epigenetic regulators TET2 and MLL3 in patients with HTLV-I-induced acute adult T-cell leukemia. Mol Cancer 2016; 15:15. [PMID: 26880370 PMCID: PMC4754821 DOI: 10.1186/s12943-016-0500-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2015] [Accepted: 02/11/2016] [Indexed: 11/27/2022] Open
Abstract
Background Epigenetic regulators play a critical role in the maintenance of specific chromatin domains in an active or repressed state. Disruption of epigenetic regulatory mechanisms is widespread in cancer cells and largely contributes to the transformation process through active repression of tumor suppressor genes. While mutations of epigenetic regulators have been reported in various lymphoid malignancies and solid cancers, mutation of these genes in HTLV-I-associated T-cell leukemia has not been investigated. Method Here we used whole genome next generation sequencing (NGS) of uncultured freshly isolated ATL samples and identified the presence of mutations in SUZ12, DNMT1, DNMT3A, DNMT3B, TET1, TET2, IDH1, IDH2, MLL, MLL2, MLL3 and MLL4. Results TET2 was the most frequently mutated gene, occurring in 32 % (10/31) of ATL samples analyzed. Interestingly, NGS revealed nonsense mutations accompanied by loss of heterozygosity (LOH) in TET2 and MLL3, which was further confirmed by cloning and direct sequencing of DNA from uncultured cells. Finally, direct sequencing of matched control and tumor samples revealed that TET2 mutation was present only in ATL tumor cells. Conclusions Our results suggest that inactivation of MLL3 and TET2 may play an important role in the tumorigenesis process of HTLV-I-induced ATL. Electronic supplementary material The online version of this article (doi:10.1186/s12943-016-0500-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Chien-Hung Yeh
- Department of Pathology, Center for Viral Oncology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS, 66160, USA
| | - Xue Tao Bai
- Department of Pathology, Center for Viral Oncology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS, 66160, USA
| | - Ramona Moles
- Department of Pathology, Center for Viral Oncology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS, 66160, USA
| | - Lee Ratner
- Department of Medicine, Division of Molecular Oncology, Washington University School of Medicine, Saint Louis, MO, 63110, USA
| | - Thomas A Waldmann
- Lymphoid Malignancies Branch, Center for Cancer Research, National Institutes of Health, Building 10, Room 4 N/115, 10 Center Drive, Bethesda, MD, 20892, USA
| | - Toshiki Watanabe
- Department of Medical Genome Sciences, University of Tokyo, Tokyo, Japan
| | - Watanabe Toshiki
- Department of Medical Genome Sciences, University of Tokyo, Tokyo, Japan
| | - Christophe Nicot
- Department of Pathology, Center for Viral Oncology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS, 66160, USA.
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Activation of the DNA Damage Response by RNA Viruses. Biomolecules 2016; 6:2. [PMID: 26751489 PMCID: PMC4808796 DOI: 10.3390/biom6010002] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 11/17/2015] [Accepted: 11/24/2015] [Indexed: 12/11/2022] Open
Abstract
RNA viruses are a genetically diverse group of pathogens that are responsible for some of the most prevalent and lethal human diseases. Numerous viruses introduce DNA damage and genetic instability in host cells during their lifecycles and some species also manipulate components of the DNA damage response (DDR), a complex and sophisticated series of cellular pathways that have evolved to detect and repair DNA lesions. Activation and manipulation of the DDR by DNA viruses has been extensively studied. It is apparent, however, that many RNA viruses can also induce significant DNA damage, even in cases where viral replication takes place exclusively in the cytoplasm. DNA damage can contribute to the pathogenesis of RNA viruses through the triggering of apoptosis, stimulation of inflammatory immune responses and the introduction of deleterious mutations that can increase the risk of tumorigenesis. In addition, activation of DDR pathways can contribute positively to replication of viral RNA genomes. Elucidation of the interactions between RNA viruses and the DDR has provided important insights into modulation of host cell functions by these pathogens. This review summarises the current literature regarding activation and manipulation of the DDR by several medically important RNA viruses.
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Bai XT, Moles R, Chaib-Mezrag H, Nicot C. Small PARP inhibitor PJ-34 induces cell cycle arrest and apoptosis of adult T-cell leukemia cells. J Hematol Oncol 2015; 8:117. [PMID: 26497583 PMCID: PMC4619390 DOI: 10.1186/s13045-015-0217-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 10/13/2015] [Indexed: 01/17/2023] Open
Abstract
Background HTLV-I is associated with the development of an aggressive form of lymphocytic leukemia known as adult T-cell leukemia/lymphoma (ATLL). A major obstacle for effective treatment of ATLL resides in the genetic diversity of tumor cells and their ability to acquire resistance to chemotherapy regimens. As a result, most patients relapse and current therapeutic approaches still have limited long-term survival benefits. Hence, the development of novel approaches is greatly needed. Methods In this study, we found that a small molecule inhibitor of poly (ADP-ribose) polymerase (PARP), PJ-34, is very effective in activating S/G2M cell cycle checkpoints, resulting in permanent cell cycle arrest and reactivation of p53 transcription functions and caspase-3-dependent apoptosis of HTLV-I-transformed and patient-derived ATLL tumor cells. We also found that HTLV-I-transformed MT-2 cells are resistant to PJ-34 therapy associated with reduced cleaved caspase-3 activation and increased expression of RelA/p65. Conclusion Since PJ-34 has been tested in clinical trials for the treatment of solid tumors, our results suggest that some ATLL patients may be good candidates to benefit from PJ-34 therapy.
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Affiliation(s)
- Xue Tao Bai
- Department of Pathology and Laboratory Medicine, Center for Viral Oncology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS, 66160, USA
| | - Ramona Moles
- Department of Pathology and Laboratory Medicine, Center for Viral Oncology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS, 66160, USA
| | - Hassiba Chaib-Mezrag
- Department of Pathology and Laboratory Medicine, Center for Viral Oncology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS, 66160, USA
| | - Christophe Nicot
- Department of Pathology and Laboratory Medicine, Center for Viral Oncology, University of Kansas Medical Center, 3901 Rainbow Boulevard, Kansas City, KS, 66160, USA.
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Nicot C. HTLV-I Tax-Mediated Inactivation of Cell Cycle Checkpoints and DNA Repair Pathways Contribute to Cellular Transformation: "A Random Mutagenesis Model". ACTA ACUST UNITED AC 2015; 2. [PMID: 26835512 DOI: 10.13188/2377-9292.1000009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
To achieve cellular transformation, most oncogenic retroviruses use transduction by proto-oncogene capture or insertional mutagenesis, whereby provirus integration disrupts expression of tumor suppressors or proto-oncogenes. In contrast, the Human T-cell leukemia virus type 1 (HTLV-I) has been classified in a separate class referred to as "transactivating retroviruses". Current views suggest that the viral encoded Tax protein transactivates expression of cellular genes leading to deregulated growth and transformation. However, if Tax-mediated transactivation was indeed sufficient for cellular transformation, a fairly high frequency of infected cells would eventually become transformed. In contrast, the frequency of transformation by HTLV-I is very low, likely less than 5%. This review will discuss the current understanding and recent discoveries highlighting critical functions of Tax in cellular transformation. HTLV-I Tax carries out essential functions in order to override cell cycle checkpoints and deregulate cellular division. In addition, Tax expression is associated with increased DNA damage and genome instability. Since Tax can inhibit multiple DNA repair pathways and stimulate unfaithful DNA repair or bypass checkpoints, these processes allow accumulation of genetic mutations in the host genome. Given this, a "Random Mutagenesis" transformation model seems more suitable to characterize the oncogenic activities of HTLV-I.
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Affiliation(s)
- Christophe Nicot
- Department of Pathology and Laboratory Medicine, Center for Viral Oncology, University of Kansas Medical Center, USA
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Baydoun HH, Cherian MA, Green P, Ratner L. Inducible nitric oxide synthase mediates DNA double strand breaks in Human T-Cell Leukemia Virus Type 1-induced leukemia/lymphoma. Retrovirology 2015; 12:71. [PMID: 26265053 PMCID: PMC4534112 DOI: 10.1186/s12977-015-0196-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 07/30/2015] [Indexed: 01/23/2023] Open
Abstract
Background Adult T-cell leukemia/lymphoma (ATLL) is an aggressive and fatal malignancy of CD4+ T-lymphocytes infected by the Human T-Cell Virus Type 1 (HTLV-1). The molecular mechanisms of transformation in ATLL have not been fully elucidated. However, genomic instability and cumulative DNA damage during the long period of latency is believed to be essential for HTLV-1 induced leukemogenesis. In addition, constitutive activation of the NF-κB pathway was found to be a critical determinant for transformation. Whether a connection exists between NF-κB activation and accumulation of DNA damage is not clear. We recently found that the HTLV-1 viral oncoprotein, Tax, the activator of the NF-κB pathway, induces DNA double strand breaks (DSBs). Results Here, we investigated whether any of the NF-κB target genes are critical in inducing DSBs. Of note, we found that inducible nitric oxide synthase (iNOS) that catalyzes the production of nitric oxide (NO) in macrophages, neutrophils and T-cells is over expressed in HTLV-1 infected and Tax-expressing cells. Interestingly, we show that in HTLV-1 infected cells, iNOS expression is Tax-dependent and specifically requires the activation of the classical NF-κB and JAK/STAT pathways. A dramatic reduction of DSBs was observed when NO production was inhibited, indicating that Tax induces DSBs through the activation of NO synthesis. Conclusions Determination of the impact of NO on HTLV-1-induced leukemogenesis opens a new area for treatment or prevention of ATLL and perhaps other cancers in which NO is produced.
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Affiliation(s)
- Hicham H Baydoun
- Division of Molecular Oncology, Department of Medicine Campus, Washington University School of Medicine, 660 South Euclid Avenue, St Louis, MO, 63110, USA.
| | - Mathew A Cherian
- Division of Molecular Oncology, Department of Medicine Campus, Washington University School of Medicine, 660 South Euclid Avenue, St Louis, MO, 63110, USA.
| | - Patrick Green
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH, USA.
| | - Lee Ratner
- Division of Molecular Oncology, Department of Medicine Campus, Washington University School of Medicine, 660 South Euclid Avenue, St Louis, MO, 63110, USA. .,Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO, USA.
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Abstract
Human T-cell leukemia virus type 1 (HTLV-1) is a retrovirus that causes cancer (Adult T cell Leukemia, ATL) and a spectrum of inflammatory diseases (mainly HTLV-associated myelopathy—tropical spastic paraparesis, HAM/TSP). Since virions are particularly unstable, HTLV-1 transmission primarily occurs by transfer of a cell carrying an integrated provirus. After transcription, the viral genomic RNA undergoes reverse transcription and integration into the chromosomal DNA of a cell from the newly infected host. The virus then replicates by either one of two modes: (i) an infectious cycle by virus budding and infection of new targets and (ii) mitotic division of cells harboring an integrated provirus. HTLV-1 replication initiates a series of mechanisms in the host including antiviral immunity and checkpoint control of cell proliferation. HTLV-1 has elaborated strategies to counteract these defense mechanisms allowing continuous persistence in humans.
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Tumor Suppressor Inactivation in the Pathogenesis of Adult T-Cell Leukemia. JOURNAL OF ONCOLOGY 2015; 2015:183590. [PMID: 26170835 PMCID: PMC4478360 DOI: 10.1155/2015/183590] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Accepted: 05/24/2015] [Indexed: 12/12/2022]
Abstract
Tumor suppressor functions are essential to control cellular proliferation, to activate the apoptosis or senescence pathway to eliminate unwanted cells, to link DNA damage signals to cell cycle arrest checkpoints, to activate appropriate DNA repair pathways, and to prevent the loss of adhesion to inhibit initiation of metastases. Therefore, tumor suppressor genes are indispensable to maintaining genetic and genomic integrity. Consequently, inactivation of tumor suppressors by somatic mutations or epigenetic mechanisms is frequently associated with tumor initiation and development. In contrast, reactivation of tumor suppressor functions can effectively reverse the transformed phenotype and lead to cell cycle arrest or death of cancerous cells and be used as a therapeutic strategy. Adult T-cell leukemia/lymphoma (ATLL) is an aggressive lymphoproliferative disease associated with infection of CD4 T cells by the Human T-cell Leukemia Virus Type 1 (HTLV-I). HTLV-I-associated T-cell transformation is the result of a multistep oncogenic process in which the virus initially induces chronic T-cell proliferation and alters cellular pathways resulting in the accumulation of genetic defects and the deregulated growth of virally infected cells. This review will focus on the current knowledge of the genetic and epigenetic mechanisms regulating the inactivation of tumor suppressors in the pathogenesis of HTLV-I.
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Modulation of DNA damage and repair pathways by human tumour viruses. Viruses 2015; 7:2542-91. [PMID: 26008701 PMCID: PMC4452920 DOI: 10.3390/v7052542] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 05/12/2015] [Indexed: 02/07/2023] Open
Abstract
With between 10% and 15% of human cancers attributable to viral infection, there is great interest, from both a scientific and clinical viewpoint, as to how these pathogens modulate host cell functions. Seven human tumour viruses have been identified as being involved in the development of specific malignancies. It has long been known that the introduction of chromosomal aberrations is a common feature of viral infections. Intensive research over the past two decades has subsequently revealed that viruses specifically interact with cellular mechanisms responsible for the recognition and repair of DNA lesions, collectively known as the DNA damage response (DDR). These interactions can involve activation and deactivation of individual DDR pathways as well as the recruitment of specific proteins to sites of viral replication. Since the DDR has evolved to protect the genome from the accumulation of deleterious mutations, deregulation is inevitably associated with an increased risk of tumour formation. This review summarises the current literature regarding the complex relationship between known human tumour viruses and the DDR and aims to shed light on how these interactions can contribute to genomic instability and ultimately the development of human cancers.
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Bai XT, Nicot C. miR-28-3p is a cellular restriction factor that inhibits human T cell leukemia virus, type 1 (HTLV-1) replication and virus infection. J Biol Chem 2015; 290:5381-90. [PMID: 25568327 DOI: 10.1074/jbc.m114.626325] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Human T cell leukemia virus, type 1 (HTLV-1) replication and spread are controlled by different viral and cellular factors. Although several anti-HIV cellular microRNAs have been described, such a regulation for HTLV-1 has not been reported. In this study, we found that miR-28-3p inhibits HTLV-1 virus expression and its replication by targeting a specific site within the genomic gag/pol viral mRNA. Because miR-28-3p is highly expressed in resting T cells, which are resistant to HTLV-1 infection, we investigated a potential protective role of miR-28-3p against de novo HTLV-1 infection. To this end, we developed a new sensitive and quantitative assay on the basis of the detection of products of reverse transcription. We demonstrate that miR-28-3p does not prevent virus receptor interaction or virus entry but, instead, induces a post-entry block at the reverse transcription level. In addition, we found that HTLV-1, subtype 1A isolates corresponding to the Japanese strain ATK-1 present a natural, single-nucleotide polymorphism within the miR-28-3p target site. As a result of this polymorphism, the ATK-1 virus sequence was not inhibited by miR-28. Interestingly, genetic studies on the transmission of the virus has shown that the ATK-1 strain, which carries a Thr-to-Cys transition mutation, is transmitted efficiently between spouses, suggesting that miR-28 may play an important role in HTLV-1 transmission.
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Affiliation(s)
- Xue Tao Bai
- From the University of Kansas Medical Center, Department of Pathology and Laboratory Medicine and Center for Viral Oncology, Kansas City, Kansas 66160
| | - Christophe Nicot
- From the University of Kansas Medical Center, Department of Pathology and Laboratory Medicine and Center for Viral Oncology, Kansas City, Kansas 66160
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