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de Carvalho L, Vieira D. Evaluation of genotoxic potential of peptides used in nuclear medicine (PSMA -617 and -11, and ubiquicidine 29-41) using a flow-cytometric, semi-automated analysis of micronuclei frequency in cell cultures. Toxicol Rep 2020; 7:304-316. [PMID: 32071884 PMCID: PMC7016341 DOI: 10.1016/j.toxrep.2020.02.003] [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] [Received: 11/04/2019] [Revised: 01/29/2020] [Accepted: 02/06/2020] [Indexed: 11/17/2022] Open
Abstract
Assays that rely on the assessment of frequency of micronuclei are important standard techniques currently used to quantify potential genotoxic damage after exposure to chemical or physical agents, such as ionizing radiation, or in pre-clinical studies, to assessment of the genotoxic potential of drugs or its components. The experiments are usually performed using conventional microscopy, but currently the protocols are being upgraded to automated approaches based on flow cytometry protocols based on the elimination of the plasma membrane by chemical agents, allowing quantification by flow cytometry. In this work, the genotoxic potential of peptides used as components of radiopharmaceuticals (PSMA-617 and 11 and Ubiquicidine) was evaluated exposing CHO-KI cells to a wide range of concentration (0.1X and 100X the maximum allowed concentration to human adults). Incubation with PSMA-11 or UBI29-41 did not induce genotoxicity. After 24 h of incubation, PSMA-617 induced genotoxicity only in non-practical concentration (100-fold). Results corroborate the safety of the pre-drugs and the wide detection range of technique.
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Affiliation(s)
| | - D.P. Vieira
- Laboratório de Radiobiologia, Centro de Biotecnologia, Instituto de Pesquisas Energéticas e Nucleares, Av. Lineu Prestes 2242, São Paulo, São Paulo, Brazil
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Genotoxic Effect in Autoimmune Diseases Evaluated by the Micronucleus Test Assay: Our Experience and Literature Review. BIOMED RESEARCH INTERNATIONAL 2015; 2015:194031. [PMID: 26339592 PMCID: PMC4538408 DOI: 10.1155/2015/194031] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 03/17/2015] [Accepted: 04/08/2015] [Indexed: 11/17/2022]
Abstract
Autoimmune diseases (AD) are classified into organ-specific, systemic, and mixed; all forms of AD share a high risk for cancer development. In AD a destructive immune response induced by autoreactive lymphocytes is started and continues with the production of autoantibodies against different targets; furthermore apoptosis failure and loss of balance in oxidative stress as a consequence of local or systemic inflammation are common features seen in AD as well. Micronucleus (MN) assay can be performed in order to evaluate loss of genetic material in a clear, accurate, fast, simple, and minimally invasive test. The MN formation in the cytoplasm of cells that have undergone proliferation is a consequence of DNA fragmentation during mitosis and the appearance of small additional nuclei during interphase. The MN test, widely accepted for in vitro and in vivo genotoxicity research, provides a sensitive marker of genomic damage associated to diverse conditions. In here, we present a review of our work and other published papers concerning genotoxic effect in AD, identified by means of the MN assay, with the aim of proposing this tool as a possible early biomarker for genotoxic damage, which is a consequence of disease progression. Additionally this biomarker could be used for follow-up, to asses genome damage associated to therapies.
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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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Cortés-Gutiérrez EI, Dávila-Rodríguez MI, Cerda-Flores RM. Chromosomal damage as prognosis marker in cervical carcinogenesis. CYTOL GENET+ 2014. [DOI: 10.3103/s0095452714030049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Lodewick J, Sampaio C, Boxus M, Rinaldi AS, Coulonval K, Willems L, Roger PP, Bex F. Acetylation at lysine 346 controls the transforming activity of the HTLV-1 Tax oncoprotein in the Rat-1 fibroblast model. Retrovirology 2013; 10:75. [PMID: 23880157 PMCID: PMC3734113 DOI: 10.1186/1742-4690-10-75] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 07/18/2013] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Transformation by the Tax oncoprotein of the human T cell leukemia virus type 1 (HTLV-1) is governed by actions on cellular regulatory signals, including modulation of specific cellular gene expression via activation of signaling pathways, acceleration of cell cycle progression via stimulation of cyclin-dependent kinase activity leading to retinoblastoma protein (pRb) hyperphosphorylation and perturbation of survival signals. These actions control early steps in T cell transformation and development of Adult T cell leukemia (ATL), an aggressive malignancy of HTLV-1 infected T lymphocytes. Post-translational modifications of Tax by phosphorylation, ubiquitination, sumoylation and acetylation have been implicated in Tax-mediated activation of the NF-κB pathway, a key function associated with Tax transforming potential. RESULTS In this study, we demonstrate that acetylation at lysine K(346) in the carboxy-terminal domain of Tax is modulated in the Tax nuclear bodies by the acetyltransferase p300 and the deacetylases HDAC5/7 and controls phosphorylation of the tumor suppressor pRb by Tax-cyclin D3-CDK4-p21(CIP) complexes. This property correlates with the inability of the acetylation deficient K(346)R mutant, but not the acetylation mimetic K(346)Q mutant, to promote anchorage-independent growth of Rat-1 fibroblasts. By contrast, acetylation at lysine K(346) had no effects on the ability of Tax carboxy-terminal PDZ-binding domain to interact with the tumor suppressor hDLG. CONCLUSIONS The identification of the acetyltransferase p300 and the deacetylase HDAC7 as enzymes modulating Tax acetylation points to new therapeutic targets for the treatment of HTLV-1 infected patients at risk of developing ATL.
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Affiliation(s)
- Julie Lodewick
- Institute for Microbiological Research J-M Wiame (IRMW), Laboratory of Microbiology, Université Libre de Bruxelles, 1, Avenue E, Gryson, Brussels, Belgium
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The multifaceted oncoprotein Tax: subcellular localization, posttranslational modifications, and NF-κB activation. Adv Cancer Res 2012; 113:85-120. [PMID: 22429853 DOI: 10.1016/b978-0-12-394280-7.00003-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The human T-cell lymphotropic virus type-I (HTLV-I) is the etiologic agent of adult T-cell leukemia/lymphoma (ATL) and of tropical spastic paraparesis/HTLV-I-associated myelopathy. Constitutive NF-κB activation by the viral oncoprotein Tax plays a crucial role in the induction and maintenance of cellular proliferation, transformation, and inhibition of apoptosis. In an attempt to provide a general view of the molecular mechanisms of constitutive Tax-induced NF-κB activation, we summarize in this review the recent body of literature that supports a major role for Tax posttranslational modifications, chiefly ubiquitination, and SUMOylation, in the NF-κB activity of Tax. These modifications indeed participate in the control of Tax subcellular localization and modulate its protein-protein interaction potential. Tax posttranslational modifications, which highlight the ability of HTLV-I to optimize its limited viral genome size, might represent an attractive target for the design of new therapies for ATL.
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Majone F, Jeang KT. Unstabilized DNA breaks in HTLV-1 Tax expressing cells correlate with functional targeting of Ku80, not PKcs, XRCC4, or H2AX. Cell Biosci 2012; 2:15. [PMID: 22541714 PMCID: PMC3448514 DOI: 10.1186/2045-3701-2-15] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2012] [Accepted: 04/27/2012] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Expression of the human T-cell leukemia virus type 1 (HTLV-1) Tax oncoprotein rapidily induces a significant increase of micronuclei (MN) and unstabilized DNA breaks in cells. Unstabilized DNA breaks can have free 3'-OH ends accessible to in situ addition of digoxygenin (DIG)-labeled dUTP using terminal deoxynucleotidyl transferase. In the present work, we used a GFP-Tax (green fluorescent protein) plasmid, which produces a functionally active GFP-tagged Tax protein, to detect the cellular target(s) for Tax which might mechanistically explain the clastogenic phenomenon. We examined the induction of MN and unstabilized DNA breaks in wild type cells and cells individually knocked out for Ku80, PKcs, XRCC4, and H2AX proteins. We also assessed in the same cells, the signal strengths produced by DIG-dUTP incorporation at the unstable DNA breaks in the presence and absence of Tax. RESULTS Cells mutated for PKcs, XRCC4 and H2AX showed increased frequency of MN and unstabilized DNA breaks in response to the expression of Tax, while cells genetically mutated for Ku80 were refractory to Tax's induction of these cytogenetic effects. Moreover, by measuring the size of DIG-dUTP incorporation signal, which indicates the extent of unstable DNA ends, we found that Tax induces larger signals than those in control cells. However, in xrs-6 cells deficient for Ku80, this Tax effect was not seen. CONCLUSIONS The data here demonstrate that clastogenic DNA damage in Tax expressing cells is explained by Tax targeting of Ku80, but not PKcs, XRCC4 or H2AX, which are all proteins directly or indirectly related to the non-homologous end-joining (NHEJ) repair system. Of note, the Ku80 protein plays an important role at the initial stage of the NHEJ repair system, protecting and stabilizing DNA-breaks. Accordingly, HTLV-1 Tax is shown to interfere with a normal cellular protective mechanism for stabilizing DNA breaks. These DNA breaks, unprotected by Ku80, are unstable and are subject to erosion or end-to-end fusion, ultimately leading to additional chromosomal aberrations.
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Affiliation(s)
- Franca Majone
- Department of Biology, Via Bassi 58/b, 35131, Padua, Italy.
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Lodewick J, Lamsoul I, Bex F. Move or die: the fate of the Tax oncoprotein of HTLV-1. Viruses 2011; 3:829-57. [PMID: 21994756 PMCID: PMC3185767 DOI: 10.3390/v3060829] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2011] [Revised: 05/31/2011] [Accepted: 06/01/2011] [Indexed: 12/12/2022] Open
Abstract
The HTLV-1 Tax protein both activates viral replication and is involved in HTLV-1-mediated transformation of T lymphocytes. The transforming properties of Tax include altering the expression of select cellular genes via activation of cellular pathways and perturbation of both cell cycle control mechanisms and apoptotic signals. The recent discovery that Tax undergoes a hierarchical sequence of posttranslational modifications that control its intracellular localization provides provocative insights into the mechanisms regulating Tax transcriptional and transforming activities.
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Affiliation(s)
- Julie Lodewick
- Institut de Recherches Microbiologiques J-M Wiame, Université Libre de Bruxelles, B-1070 Bruxelles, Belgium.
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9
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Ducu RI, Dayaram T, Marriott SJ. The HTLV-1 Tax oncoprotein represses Ku80 gene expression. Virology 2011; 416:1-8. [PMID: 21571351 DOI: 10.1016/j.virol.2011.04.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 02/13/2011] [Accepted: 04/24/2011] [Indexed: 12/20/2022]
Abstract
The HTLV-I oncoprotein Tax interferes with DNA double strand break repair. Since non-homologous end joining (NHEJ) is a major pathway used to repair DNA double strand breaks we examined the effect of Tax on this pathway, with particular interest in the expression and function of Ku80, a critical component of the NHEJ pathway. Tax expression decreased Ku80 mRNA and protein levels, and repressed transcription from the Ku80 promoter. Conversely, Ku80 mRNA increased following siRNA knockdown of Tax in HTLV-I infected cells. Tax expression was associated with an elevated number of micronuclei and nucleoplasmic bridges, hallmarks of improper DNA double strand break repair. Our studies identified Tax as a transcriptional repressor of Ku80 that correlates with decreased DNA repair function. The reduction of Ku80 transcription by Tax may deplete the cell of an essential DNA break binding protein, resulting in reduced repair of DNA double strand breaks and accumulation genomic mutations.
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Affiliation(s)
- Razvan I Ducu
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA.
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10
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Cortés-Gutiérrez EI, Dávila-Rodríguez MI, Fernández JL, López-Fernández C, Gosálvez J. Koilocytes are enriched for alkaline-labile sites. Eur J Histochem 2011; 54:e32. [PMID: 21337807 PMCID: PMC3167319 DOI: 10.4081/ejh.2010.e32] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
This study investigated possible variations in the chromatin structure of koilocytes resulting from human papillomavirus (HPV) infection. Alkaline-labile sites (ALS) were detected with the DNA breakage detection–fluorescence in situ hybridization (DBD-FISH) technique using a whole human genome DNA probe obtained from individuals without koilocytosis. The variable levels of ALS present were measured quantitatively using image analysis after whole-genome DNA hybridization. A significant increase in the number of ALS was observed in koilocytes compared with normal cells. We demonstrated that the presence of ALS could be an indicator of chromatin change in koilocytes caused by HPV infection.
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Affiliation(s)
- E I Cortés-Gutiérrez
- División de Genética, Centro de Investigación Biomédica del Noreste, Instituto Mexicano del Seguro Social, IMSS, Monterrey, México.
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Human T-cell leukemia virus type 1 (HTLV-1) and leukemic transformation: viral infectivity, Tax, HBZ and therapy. Oncogene 2010; 30:1379-89. [PMID: 21119600 DOI: 10.1038/onc.2010.537] [Citation(s) in RCA: 201] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The human T-cell leukemia virus type 1 (HTLV-1) was the first retrovirus discovered to be causative of a human cancer, adult T-cell leukemia. The transforming entity of HTLV-1 has been attributed to the virally-encoded oncoprotein, Tax. Unlike the v-onc proteins encoded by other oncogenic animal retroviruses that transform cells, Tax does not originate from a c-onc counterpart. In this article, we review progress in our understanding of HTLV-1 infectivity, cellular transformation, anti-sense transcription and therapy, 30 years after the original discovery of this virus.
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12
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Jeang KT. HTLV-1 and adult T-cell leukemia: insights into viral transformation of cells 30 years after virus discovery. J Formos Med Assoc 2010; 109:688-93. [PMID: 20970064 DOI: 10.1016/s0929-6646(10)60112-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2010] [Revised: 08/02/2010] [Accepted: 08/02/2010] [Indexed: 12/22/2022] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-1), the etiological agent of adult T-cell leukemia, was the first human retrovirus to be isolated. It is now the 30(th) anniversary of the initial discovery of HTLV-1. This review discusses recent insights into the role of the HTLV-1 Tax oncoprotein in cellular proliferation and the abrogation of cellular checkpoints that lead to disease progression.
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Affiliation(s)
- Kuan-Teh Jeang
- National Institutes of Health, Bethesda, Maryland 20892, USA.
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Kinjo T, Ham-Terhune J, Peloponese JM, Jeang KT. Induction of reactive oxygen species by human T-cell leukemia virus type 1 tax correlates with DNA damage and expression of cellular senescence marker. J Virol 2010; 84:5431-7. [PMID: 20219913 PMCID: PMC2863840 DOI: 10.1128/jvi.02460-09] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2009] [Accepted: 02/27/2010] [Indexed: 01/29/2023] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) Tax affects cellular genomic stability and senescence. As yet, the mechanism(s) for these events caused by Tax is incompletely understood. Here, we show that Tax expression in primary human cells induces reactive oxygen species (ROS), which elicits DNA damage and the expression of senescence marker. Treatment with a ROS scavenger or knockdown of Tax expression by small interfering RNA (siRNA) abrogated Tax-induced DNA damage and the expression of senescence marker. Our data suggest that ROS induction explains Tax-induced cellular DNA damage and cellular senescence.
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Affiliation(s)
- Takao Kinjo
- Molecular Virology Section, Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, Division of Pathology and Cell Biology, Graduate School and Faculty of Medicine, University of the Ryukyus, Okinawa 903-0215, Japan, Division of Morphological Pathology, Department of Basic Laboratory Sciences, School of Health Sciences, University of the Ryukyus, Okinawa 903-0215, Japan, CNRS and Université Montpellier 1, UM5236, Centre d'Études d'Agents Pathogènes et Biotechnologies pour la Santé (CPBS), Montpellier F-34965, France, CPBS, Université Montpellier 2, Montpellier F-34095, France
| | - Julia Ham-Terhune
- Molecular Virology Section, Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, Division of Pathology and Cell Biology, Graduate School and Faculty of Medicine, University of the Ryukyus, Okinawa 903-0215, Japan, Division of Morphological Pathology, Department of Basic Laboratory Sciences, School of Health Sciences, University of the Ryukyus, Okinawa 903-0215, Japan, CNRS and Université Montpellier 1, UM5236, Centre d'Études d'Agents Pathogènes et Biotechnologies pour la Santé (CPBS), Montpellier F-34965, France, CPBS, Université Montpellier 2, Montpellier F-34095, France
| | - Jean-Marie Peloponese
- Molecular Virology Section, Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, Division of Pathology and Cell Biology, Graduate School and Faculty of Medicine, University of the Ryukyus, Okinawa 903-0215, Japan, Division of Morphological Pathology, Department of Basic Laboratory Sciences, School of Health Sciences, University of the Ryukyus, Okinawa 903-0215, Japan, CNRS and Université Montpellier 1, UM5236, Centre d'Études d'Agents Pathogènes et Biotechnologies pour la Santé (CPBS), Montpellier F-34965, France, CPBS, Université Montpellier 2, Montpellier F-34095, France
| | - Kuan-Teh Jeang
- Molecular Virology Section, Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, Division of Pathology and Cell Biology, Graduate School and Faculty of Medicine, University of the Ryukyus, Okinawa 903-0215, Japan, Division of Morphological Pathology, Department of Basic Laboratory Sciences, School of Health Sciences, University of the Ryukyus, Okinawa 903-0215, Japan, CNRS and Université Montpellier 1, UM5236, Centre d'Études d'Agents Pathogènes et Biotechnologies pour la Santé (CPBS), Montpellier F-34965, France, CPBS, Université Montpellier 2, Montpellier F-34095, France
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Chaurushiya MS, Weitzman MD. Viral manipulation of DNA repair and cell cycle checkpoints. DNA Repair (Amst) 2009; 8:1166-76. [PMID: 19473887 DOI: 10.1016/j.dnarep.2009.04.016] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Recognition and repair of DNA damage is critical for maintaining genomic integrity and suppressing tumorigenesis. In eukaryotic cells, the sensing and repair of DNA damage are coordinated with cell cycle progression and checkpoints, in order to prevent the propagation of damaged DNA. The carefully maintained cellular response to DNA damage is challenged by viruses, which produce a large amount of exogenous DNA during infection. Viruses also express proteins that perturb cellular DNA repair and cell cycle pathways, promoting tumorigenesis in their quest for cellular domination. This review presents an overview of strategies employed by viruses to manipulate DNA damage responses and cell cycle checkpoints as they commandeer the cell to maximize their own viral replication. Studies of viruses have identified key cellular regulators and revealed insights into molecular mechanisms governing DNA repair, cell cycle checkpoints, and transformation.
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Affiliation(s)
- Mira S Chaurushiya
- Laboratory of Genetics, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
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15
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Durkin SS, Guo X, Fryrear KA, Mihaylova VT, Gupta SK, Belgnaoui SM, Haoudi A, Kupfer GM, Semmes OJ. HTLV-1 Tax oncoprotein subverts the cellular DNA damage response via binding to DNA-dependent protein kinase. J Biol Chem 2008; 283:36311-20. [PMID: 18957425 PMCID: PMC2605996 DOI: 10.1074/jbc.m804931200] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Human T-cell leukemia virus type-1 is the causative agent for adult T-cell leukemia. Previous research has established that the viral oncoprotein Tax mediates the transformation process by impairing cell cycle control and cellular response to DNA damage. We showed previously that Tax sequesters huChk2 within chromatin and impairs the response to ionizing radiation. Here we demonstrate that DNA-dependent protein kinase (DNA-PK) is a member of the Tax.Chk2 nuclear complex. The catalytic subunit, DNA-PKcs, and the regulatory subunit, Ku70, were present. Tax-containing nuclear extracts showed increased DNA-PK activity, and specific inhibition of DNA-PK prevented Tax-induced activation of Chk2 kinase activity. Expression of Tax induced foci formation and phosphorylation of H2AX. However, Tax-induced constitutive signaling of the DNA-PK pathway impaired cellular response to new damage, as reflected in suppression of ionizing radiation-induced DNA-PK phosphorylation and gammaH2AX stabilization. Tax co-localized with phospho-DNA-PK into nuclear speckles and a nuclear excluded Tax mutant sequestered endogenous phospho-DNA-PK into the cytoplasm, suggesting that Tax interaction with DNA-PK is an initiating event. We also describe a novel interaction between DNA-PK and Chk2 that requires Tax. We propose that Tax binds to and stabilizes a protein complex with DNA-PK and Chk2, resulting in a saturation of DNA-PK-mediated damage repair response.
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Affiliation(s)
- Sarah S Durkin
- Department of Microbiology and Molecular Cell Biology, Center for Biomedical Proteomics, Eastern Virginia Medical School, Norfolk, Virginia 23507, USA
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16
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Ramadan E, Ward M, Guo X, Durkin SS, Sawyer A, Vilela M, Osgood C, Pothen A, Semmes OJ. Physical and in silico approaches identify DNA-PK in a Tax DNA-damage response interactome. Retrovirology 2008; 5:92. [PMID: 18922151 PMCID: PMC2576351 DOI: 10.1186/1742-4690-5-92] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Accepted: 10/15/2008] [Indexed: 12/16/2022] Open
Abstract
Background We have initiated an effort to exhaustively map interactions between HTLV-1 Tax and host cellular proteins. The resulting Tax interactome will have significant utility toward defining new and understanding known activities of this important viral protein. In addition, the completion of a full Tax interactome will also help shed light upon the functional consequences of these myriad Tax activities. The physical mapping process involved the affinity isolation of Tax complexes followed by sequence identification using tandem mass spectrometry. To date we have mapped 250 cellular components within this interactome. Here we present our approach to prioritizing these interactions via an in silico culling process. Results We first constructed an in silico Tax interactome comprised of 46 literature-confirmed protein-protein interactions. This number was then reduced to four Tax-interactions suspected to play a role in DNA damage response (Rad51, TOP1, Chk2, 53BP1). The first-neighbor and second-neighbor interactions of these four proteins were assembled from available human protein interaction databases. Through an analysis of betweenness and closeness centrality measures, and numbers of interactions, we ranked proteins in the first neighborhood. When this rank list was compared to the list of physical Tax-binding proteins, DNA-PK was the highest ranked protein common to both lists. An overlapping clustering of the Tax-specific second-neighborhood protein network showed DNA-PK to be one of three bridge proteins that link multiple clusters in the DNA damage response network. Conclusion The interaction of Tax with DNA-PK represents an important biological paradigm as suggested via consensus findings in vivo and in silico. We present this methodology as an approach to discovery and as a means of validating components of a consensus Tax interactome.
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Affiliation(s)
- Emad Ramadan
- George L, Wright Center for Biomedical Proteomics, Eastern Virginia Medical School, Norfolk, VA, USA.
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Boxus M, Twizere JC, Legros S, Dewulf JF, Kettmann R, Willems L. The HTLV-1 Tax interactome. Retrovirology 2008; 5:76. [PMID: 18702816 PMCID: PMC2533353 DOI: 10.1186/1742-4690-5-76] [Citation(s) in RCA: 195] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2008] [Accepted: 08/14/2008] [Indexed: 12/22/2022] Open
Abstract
The Tax1 oncoprotein encoded by Human T-lymphotropic virus type I is a major determinant of viral persistence and pathogenesis. Tax1 affects a wide variety of cellular signalling pathways leading to transcriptional activation, proliferation and ultimately transformation. To carry out these functions, Tax1 interacts with and modulates activity of a number of cellular proteins. In this review, we summarize the present knowledge of the Tax1 interactome and propose a rationale for the broad range of cellular proteins identified so far.
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Affiliation(s)
- Mathieu Boxus
- University Academia Wallonie-Europe, Molecular and Cellular Biology at FUSAGx, Gembloux, Belgium.
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18
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Dayaram T, Marriott SJ. Effect of transforming viruses on molecular mechanisms associated with cancer. J Cell Physiol 2008; 216:309-14. [PMID: 18366075 DOI: 10.1002/jcp.21439] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Viruses have been linked to approximately 20% of all human tumors worldwide. These transforming viruses encode viral oncoproteins that interact with cellular proteins to enhance viral replication. The transcriptional and post-transcriptional effects of these viral oncoproteins ultimately result in cellular transformation. Historically, viral research has been vital to the discovery of oncogenes and tumor suppressors with more current research aiding in unraveling some mechanisms of carcinogenesis. Interestingly, since transforming viruses affect some of the same pathways that are dysregulated in human cancers, their study enhances our understanding of the multistep process of tumorigenesis. This review will examine the cellular mechanisms targeted by oncogenic human viruses and the processes by which these effects contribute to transformation. In particular, we will focus on three transforming viruses, human T-cell leukemia virus type-I, hepatitis B virus and human papillomavirus. These viruses all encode specific oncogenes that promote cell cycle progression, inhibit DNA damage checkpoint responses and prevent programmed cell death in an effort to promote viral propagation. While the transforming properties of these viruses are probably unintended consequences of replication strategies, they provide excellent systems in which to study cancer development.
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Affiliation(s)
- Tajhal Dayaram
- Interdepartmental Program in Cell and Molecular Biology, Department of Molecular Virology and Microbiology, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA
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Laybourn P. The ups and downs of Tax and histones in adult T-cell leukemogenesis. Future Oncol 2008; 4:311-7. [PMID: 18518755 DOI: 10.2217/14796694.4.3.311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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20
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Peloponese JM, Kinjo T, Jeang KT. Human T-cell leukemia virus type 1 Tax and cellular transformation. Int J Hematol 2007; 86:101-6. [PMID: 17875521 DOI: 10.1532/ijh97.07087] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Infection of T-cells by human T-cell leukemia virus type 1 (HTLV-1) causes a lymphoproliferative malignancy known as adult T-cell leukemia (ATL). ATL is characterized by abnormal lymphocytes, called flower cells, which have cleaved and convoluted nuclei. Tax, encoded by the HTLV-1 pX region, is a critical nonstructural protein that plays a central role in leukemogenesis; however, the mechanisms of HTLV-1 oncogenesis have not been clarified fully. In this review, we summarize current thinking on how Tax may affect ATL leukemogenesis.
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Affiliation(s)
- Jean-Marie Peloponese
- Molecular Virology Section, Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892-0460, USA
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21
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Majone F, Cozzi F, Tonello M, Olivieri S, Montaldi A, Favaro M, Visentin S, Luisetto R, Ruffatti A. Unstabilized DNA breaks in lymphocytes of patients with different subsets of systemic sclerosis. Ann N Y Acad Sci 2007; 1108:240-8. [PMID: 17893989 DOI: 10.1196/annals.1422.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The clastogenic effects on DNA, proven by the presence of micronuclei (MN) and the protective cellular mechanisms normally used to stabilize DNA breaks were investigated in three subsets of patients with systemic sclerosis (SSc). The frequency of MN found in cultures of peripheral lymphocytes in patients with anticentromere and antitopoisomerase I antibodies was significantly higher than that in the control group. The group with anticentromere antibody showed a significantly higher frequency of MN than did the subjects with antitopoisomerase antibody (4.22% versus 2.34%, P < 0.001). Patients with anti-RNA polymerase III, instead, had a low prevalence of typical micronucleated cells (0.98%), not significantly different from that of the healthy controls (0.82%). Moreover, when MN was characterized for the presence or absence of DNA fragments with free 3'-OH ends by digoxigenin-dUTP (DIG-dUTP) using terminal deoxynucleotidil transferase, its frequency was found to be increased in the groups with anticentromere and antitopoisomerase I antibodies with respect to that in the controls. The increase was significantly higher in the lymphocytes of the patients with anticentromere than in those with antitopoisomerase I antibody (35% versus 20.08%, P < 0.001). Nonetheless, the prevalence of unstable DNA fragments in patients with anti-RNA polymerase III antibody was low (2.05%) and not significantly different from that of the control group (1.18%). Our results indicate that there is a clastogenic effect on DNA and an interference in the protective cellular mechanisms normally stabilizing DNA breaks only in some subsets of SSc patients.
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Affiliation(s)
- Franca Majone
- Department of Biology, University of Padua, Padua, Italy
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22
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Gupta SK, Guo X, Durkin SS, Fryrear KF, Ward MD, Semmes OJ. Human T-cell Leukemia Virus Type 1 Tax Oncoprotein Prevents DNA Damage-induced Chromatin Egress of Hyperphosphorylated Chk2. J Biol Chem 2007; 282:29431-40. [PMID: 17698850 DOI: 10.1074/jbc.m704110200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
De novo expression of human T-cell leukemia virus type 1 Tax results in cellular genomic instability. We demonstrated previously that Tax associates with the cell cycle check point regulator Chk2 and proposed that the inappropriate activation of Chk2 provides a model for Tax-induced loss of genetic integrity (Haoudi, A., Daniels, R. C., Wong, E., Kupfer, G., and Semmes, O. J. (2003) J. Biol. Chem. 278, 37736-37744). Here we provide an explanation for how Tax induces some Chk2 activities but represses others. We show that Tax interaction with Chk2 generates two activation signals in Chk2, oligomerization and autophosphorylation. However, egress of Chk2 from chromatin, normally observed in response to ionizing radiation, was repressed in Tax-expressing cells. Analysis of chromatin-bound Chk2 from Tax-expressing cells revealed phosphorylation at Thr(378), Ser(379), Thr(383), Thr(387), and Thr(389). In contrast, chromatin-bound Chk2 in the absence of Tax was phosphorylated at Thr(383) and Thr(387) in response to ionizing radiation. We further establish that Tax binds to the kinase domain of Chk2. Confocal microscopy revealed a redistribution of Chk2 to colocalize with Tax in Tax speckled structures, which we have shown previously to coincide with interchromatin granules. We propose that Tax binding via the Chk2 kinase domain sequesters phosphorylated Chk2 within chromatin, thus hindering chromatin egress and appropriate response to DNA damage.
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Affiliation(s)
- Saurabh K Gupta
- Department of Microbiology and Molecular Cell Biology, Eastern Virginia Medical School, Norfolk, Virginia 23507, USA
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23
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Siddiqui K, Del Valle L, Morellet N, Cui J, Ghafouri M, Mukerjee R, Urbanska K, Fan S, Pattillo CB, Deshmane SL, Kiani MF, Ansari R, Khalili K, Roques BP, Reiss K, Bouaziz S, Amini S, Srinivasan A, Sawaya BE. Molecular mimicry in inducing DNA damage between HIV-1 Vpr and the anticancer agent, cisplatin. Oncogene 2007; 27:32-43. [PMID: 17653096 DOI: 10.1038/sj.onc.1210632] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The human immunodeficiency virus type 1 (HIV-1) viral protein R (vpr) gene is an evolutionarily conserved gene among the primate lentiviruses. Several functions are attributed to Vpr including the ability to cause cell death, cell cycle arrest, apoptosis and DNA damage. The Vpr domain responsible for DNA damage as well as the mechanism(s) through which Vpr induces this damage is unknown. Using site-directed mutagenesis, we identified the helical domain II within Vpr (aa 37-50) as the region responsible for causing DNA damage. Interestingly, Vpr Delta(37-50) failed to cause cell cycle arrest or apoptosis, to induce Ku70 or Ku80 and to suppress tumor growth, but maintained its capability to activate the HIV-1 LTR, to localize to the nucleus and to promote nonhomologous end-joining. In addition, our cytogenetic data indicated that helical domain II induced chromosomal aberrations, which mimicked those induced by cisplatin, an anticancer agent. This novel molecular mimicry function of Vpr might lead to its potential therapeutic use as a tumor suppressor.
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Affiliation(s)
- K Siddiqui
- 1Department of Biology, College of Science and Technology, Temple University, Philadelphia, PA, USA
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Matsuoka M, Jeang KT. Human T-cell leukaemia virus type 1 (HTLV-1) infectivity and cellular transformation. Nat Rev Cancer 2007; 7:270-80. [PMID: 17384582 DOI: 10.1038/nrc2111] [Citation(s) in RCA: 606] [Impact Index Per Article: 35.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
It has been 30 years since a 'new' leukaemia termed adult T-cell leukaemia (ATL) was described in Japan, and more than 25 years since the isolation of the retrovirus, human T-cell leukaemia virus type 1 (HTLV-1), that causes this disease. We discuss HTLV-1 infectivity and how the HTLV-1 Tax oncoprotein initiates transformation by creating a cellular environment favouring aneuploidy and clastogenic DNA damage. We also explore the contribution of a newly discovered protein and RNA on the HTLV-1 minus strand, HTLV-1 basic leucine zipper factor (HBZ), to the maintenance of virus-induced leukaemia.
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Affiliation(s)
- Masao Matsuoka
- Laboratory of Virus Immunology, Institute for Virus Research, Kyoto University, Japan
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25
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Silbermann K, Grassmann R. Human T cell leukemia virus type 1 Tax-induced signals in cell survival, proliferation, and transformation. ACTA ACUST UNITED AC 2007. [DOI: 10.1002/sita.200600119] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Site-specific Phosphorylation Differentiates Active from Inactive Forms of the Human T-cell Leukemia Virus Type 1 Tax Oncoprotein. J Biol Chem 2006. [DOI: 10.1016/s0021-9258(19)84084-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Durkin SS, Ward MD, Fryrear KA, Semmes OJ. Site-specific phosphorylation differentiates active from inactive forms of the human T-cell leukemia virus type 1 Tax oncoprotein. J Biol Chem 2006; 281:31705-12. [PMID: 16923801 DOI: 10.1074/jbc.m607011200] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The human T-cell leukemia virus type 1 oncoprotein Tax is a phosphoprotein with a predominately nuclear subcellular localization that accomplishes multiple functions via protein-protein interactions. It has been proposed that regulation of this protein's pleiotropic functions may be accomplished through phosphorylation of specific amino acid residues. We have conducted a phosphoryl mapping of mammalian-expressed Tax protein using a combination of affinity purification, liquid chromatography tandem mass spectrometry, and site-directed substitution mutational analysis. We achieved physical coverage of 77% of the Tax sequence and identified four novel sites of phosphorylation at Thr-48, Thr-184, Thr-215, and Ser-336. Previously identified potential serine phosphorylation sites at Ser-10, Ser-77, and Ser-274 could not be confirmed by mass spectrometry. The functional significance of these novel phosphorylation events was evaluated by mutational analysis and subsequent evaluation for activity via both CREB and NF-kappaB-responsive promoters. Our results demonstrate that phosphorylation at Thr-215 is associated with loss of both Tax functions, phosphorylation at Thr-48 was specifically deficient for activation via NF-kappaB, and phosphorylation at Thr-184 and Ser-336 had no effect on these Tax functions. Semiquantitation of phosphopeptides revealed that the majority of Tax was phosphorylated at Thr-48, Thr-184, Thr-215, and Ser-336, whereas only a minor population of Tax was phosphorylated at either Ser-300 or Ser-301. These results suggest that both positive and negative phosphorylation signals result in the maintenance of a subfraction of Tax as "active" protein.
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Affiliation(s)
- Sarah S Durkin
- Department of Microbiology and Molecular Cell Biology, Center for Biomedical Proteomics, Eastern Virginia Medical School, Norfolk, Virginia 23507, USA
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Pumfery A, de la Fuente C, Kashanchi F. HTLV-1 Tax: centrosome amplification and cancer. Retrovirology 2006; 3:50. [PMID: 16899128 PMCID: PMC1555608 DOI: 10.1186/1742-4690-3-50] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2006] [Accepted: 08/09/2006] [Indexed: 11/16/2022] Open
Abstract
During interphase, each cell contains a single centrosome that acts as a microtubule organizing center for cellular functions in interphase and in mitosis. Centrosome amplification during the S phase of the cell cycle is a tightly regulated process to ensure that each daughter cell receives the proper complement of the genome. The controls that ensure that centrosomes are duplicated exactly once in the cell cycle are not well understood. In solid tumors and hematological malignancies, centrosome abnormalities resulting in aneuploidy is observed in the majority of cancers. These phenotypes are also observed in cancers induced by viruses, including adult T cell lymphoma which is caused by the human T cell lymphotrophic virus Type 1 (HTLV-1). Several reports have indicated that the HTLV-1 transactivator, Tax, is directly responsible for the centrosomal abnormalities observed in ATL cells. A recent paper in Nature Cell Biology by Ching et al. has shed some new light into how Tax may be inducing centrosome abnormalities. The authors demonstrated that 30% of ATL cells contained more than two centrosomes and expression of Tax alone induced supernumerary centrosomes. A cellular coiled-coil protein, Tax1BP2, was shown to interact with Tax and disruption of this interaction led to failure of Tax to induce centrosome amplification. Additionally, down-regulation of Tax1BP2 led to centrosome amplification. These results suggest that Tax1BP2 may be an important block to centrosome re-duplication that is observed in normal cells. Presently, a specific cellular protein that prevents centrosome re-duplication has not been identified. This paper has provided further insight into how Tax induces centrosome abnormalities that lead to ATL. Lastly, additional work on Tax1BP2 will also provide insight into how the cell suppresses centrosome re-duplication during the cell cycle and the role that Tax1BP2 plays in this important cellular pathway.
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Affiliation(s)
- Anne Pumfery
- Seton Hall University, Department of Biology, South Orange, NJ 07079, USA
| | - Cynthia de la Fuente
- The Rockefeller University, Laboratory of Virology and Infectious Disease, New York, NY 10021, USA
| | - Fatah Kashanchi
- The George Washington University Medical Center, Department of Biochemistry and Molecular Biology, Washington, DC 20037, USA
- The Institute for Genomic Research, Rockville, Maryland 20850, USA
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de la Fuente C, Gupta MV, Klase Z, Strouss K, Cahan P, McCaffery T, Galante A, Soteropoulos P, Pumfery A, Fujii M, Kashanchi F. Involvement of HTLV-I Tax and CREB in aneuploidy: a bioinformatics approach. Retrovirology 2006; 3:43. [PMID: 16822311 PMCID: PMC1553470 DOI: 10.1186/1742-4690-3-43] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2006] [Accepted: 07/05/2006] [Indexed: 11/23/2022] Open
Abstract
Background Adult T-cell leukemia (ATL) is a complex and multifaceted disease associated with human T-cell leukemia virus type 1 (HTLV-I) infection. Tax, the viral oncoprotein, is considered a major contributor to cell cycle deregulation in HTLV-I transformed cells by either directly disrupting cellular factors (protein-protein interactions) or altering their transcription profile. Tax transactivates these cellular promoters by interacting with transcription factors such as CREB/ATF, NF-κB, and SRF. Therefore by examining which factors upregulate a particular set of promoters we may begin to understand how Tax orchestrates leukemia development. Results We observed that CTLL cells stably expressing wild-type Tax (CTLL/WT) exhibited aneuploidy as compared to a Tax clone deficient for CREB transactivation (CTLL/703). To better understand the contribution of Tax transactivation through the CREB/ATF pathway to the aneuploid phenotype, we performed microarray analysis comparing CTLL/WT to CTLL/703 cells. Promoter analysis of altered genes revealed that a subset of these genes contain CREB/ATF consensus sequences. While these genes had diverse functions, smaller subsets of genes were found to be involved in G2/M phase regulation, in particular kinetochore assembly. Furthermore, we confirmed the presence of CREB, Tax and RNA Polymerase II at the p97Vcp and Sgt1 promoters in vivo through chromatin immunoprecipitation in CTLL/WT cells. Conclusion These results indicate that the development of aneuploidy in Tax-expressing cells may occur in response to an alteration in the transcription profile, in addition to direct protein interactions.
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MESH Headings
- Aneuploidy
- Binding Sites
- Chromatin Immunoprecipitation
- Computational Biology/methods
- Cyclic AMP Response Element-Binding Protein/genetics
- Cyclic AMP Response Element-Binding Protein/metabolism
- DNA Polymerase II/genetics
- DNA Polymerase II/metabolism
- Gene Expression Profiling/methods
- Gene Expression Regulation
- Gene Products, tax/biosynthesis
- Gene Products, tax/genetics
- Gene Products, tax/metabolism
- Genes, pX
- Human T-lymphotropic virus 1/genetics
- Humans
- Kinetochores/physiology
- Leukemia, Prolymphocytic, T-Cell/genetics
- Leukemia, Prolymphocytic, T-Cell/virology
- Oligonucleotide Array Sequence Analysis
- Promoter Regions, Genetic
- T-Lymphocytes, Cytotoxic/metabolism
- T-Lymphocytes, Cytotoxic/physiology
- Transfection
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Affiliation(s)
- Cynthia de la Fuente
- The George Washington University Medical Center, Department of Biochemistry and Molecular Biology, Washington, DC 20037, USA
| | - Madhur V Gupta
- The George Washington University Medical Center, Department of Biochemistry and Molecular Biology, Washington, DC 20037, USA
| | - Zachary Klase
- The George Washington University Medical Center, Department of Biochemistry and Molecular Biology, Washington, DC 20037, USA
| | - Katharine Strouss
- The George Washington University Medical Center, Department of Biochemistry and Molecular Biology, Washington, DC 20037, USA
| | - Patrick Cahan
- The George Washington University Medical Center, Department of Biochemistry and Molecular Biology, Washington, DC 20037, USA
| | - Timothy McCaffery
- The George Washington University Medical Center, Department of Biochemistry and Molecular Biology, Washington, DC 20037, USA
| | - Anthony Galante
- Center for Applied Genomics, Public Health Research Institute, Newark, NJ 07103, USA
| | - Patricia Soteropoulos
- Center for Applied Genomics, Public Health Research Institute, Newark, NJ 07103, USA
| | - Anne Pumfery
- The George Washington University Medical Center, Department of Biochemistry and Molecular Biology, Washington, DC 20037, USA
| | - Masahiro Fujii
- Department of Immunotherapeutics, Niigata University School of Medicine, Asahimachi-Dori, Niigata 951-8510, Japan
- Department of Virology, Niigata University School of Medicine, Asahimachi-Dori, Niigata 951-8510, Japan
| | - Fatah Kashanchi
- The George Washington University Medical Center, Department of Biochemistry and Molecular Biology, Washington, DC 20037, USA
- The Institute for Genomic Research (TIGR), Rockville, MD 20850, USA
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Peloponese JM, Jeang KT. Role for Akt/Protein Kinase B and Activator Protein-1 in Cellular Proliferation Induced by the Human T-cell Leukemia Virus Type 1 Tax Oncoprotein. J Biol Chem 2006; 281:8927-38. [PMID: 16436385 DOI: 10.1074/jbc.m510598200] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Human T-cell leukemia virus type 1 is an oncogenic retrovirus etiologically causal of adult T-cell leukemia. The virus encodes a Tax oncoprotein, which functions in transcriptional regulation, cell cycle control, and transformation. Because adult T-cell leukemia is a highly virulent cancer that is resistant to numerous chemotherapeutic treatments, to understand better this disease it is important to comprehend how human T-cell leukemia virus type 1 promotes cellular growth and survival. Most of the existing data point to Tax activation of NF-kappaB as important for cellular proliferation and transformation. We show here that Tax, in the absence of NF-kappaB signaling, can activate activator protein-1 to promote cellular proliferation and survival. Tax is shown to activate activator protein-1 through the phosphatidylinositol 3-kinase/Akt pathway.
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Affiliation(s)
- Jean-Marie Peloponese
- Molecular Virology Section, Laboratory of Molecular Microbiology, NIAID, National Institutes of Health, Bethesda, Maryland 20892-0460, USA
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