1
|
Kiik H, Ramanayake S, Miura M, Tanaka Y, Melamed A, Bangham CRM. Time-course of host cell transcription during the HTLV-1 transcriptional burst. PLoS Pathog 2022; 18:e1010387. [PMID: 35576236 PMCID: PMC9135347 DOI: 10.1371/journal.ppat.1010387] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 05/26/2022] [Accepted: 04/22/2022] [Indexed: 12/30/2022] Open
Abstract
The human T-cell leukemia virus type 1 (HTLV-1) transactivator protein Tax has pleiotropic functions in the host cell affecting cell-cycle regulation, DNA damage response pathways and apoptosis. These actions of Tax have been implicated in the persistence and pathogenesis of HTLV-1-infected cells. It is now known that tax expression occurs in transcriptional bursts of the proviral plus-strand, but the effects of the burst on host transcription are not fully understood. We carried out RNA sequencing of two naturally-infected T-cell clones transduced with a Tax-responsive Timer protein, which undergoes a time-dependent shift in fluorescence emission, to study transcriptional changes during successive phases of the HTLV-1 plus-strand burst. We found that the transcriptional regulation of genes involved in the NF-κB pathway, cell-cycle regulation, DNA damage response and apoptosis inhibition were immediate effects accompanying the plus-strand burst, and are limited to the duration of the burst. The results distinguish between the immediate and delayed effects of HTLV-1 reactivation on host transcription, and between clone-specific effects and those observed in both clones. The major transcriptional changes in the infected host T-cells observed here, including NF-κB, are transient, suggesting that these pathways are not persistently activated at high levels in HTLV-1-infected cells. The two clones diverged strongly in their expression of genes regulating the cell cycle. Up-regulation of senescence markers was a delayed effect of the proviral plus-strand burst and the up-regulation of some pro-apoptotic genes outlasted the burst. We found that activation of the aryl hydrocarbon receptor (AhR) pathway enhanced and prolonged the proviral burst, but did not increase the rate of reactivation. Our results also suggest that sustained plus-strand expression is detrimental to the survival of infected cells.
Collapse
Affiliation(s)
- Helen Kiik
- Department of Infectious Diseases, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Saumya Ramanayake
- Department of Infectious Diseases, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Michi Miura
- Department of Infectious Diseases, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Yuetsu Tanaka
- Department of Infectious Disease and Immunology, Okinawa-Asia Research Center of Medical Science, Faculty of Medicine, University of the Ryukyus, Nishihara, Okinawa, Japan
| | - Anat Melamed
- Department of Infectious Diseases, Faculty of Medicine, Imperial College London, London, United Kingdom
| | - Charles R. M. Bangham
- Department of Infectious Diseases, Faculty of Medicine, Imperial College London, London, United Kingdom
| |
Collapse
|
2
|
Pawlonka J, Rak B, Ambroziak U. The regulation of cyclin D promoters - review. Cancer Treat Res Commun 2021; 27:100338. [PMID: 33618151 DOI: 10.1016/j.ctarc.2021.100338] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 02/06/2021] [Accepted: 02/15/2021] [Indexed: 11/25/2022]
Abstract
Cyclins are key regulators of cell cycle progression and survival. Particularly cyclins D (cyclin D1, D2, and D3) act in response to the mitogenic stimulation and are pivotal mediators between proliferative pathways and the nuclear cell cycle machinery. Dysregulation of cyclins expression results in impaired development, abnormal cell growth or tumorigenesis. In this review we summarize current knowledge about regulatory role of the cyclin D promoters, transcriptional factors: regulators, co-activators and adaptor proteins necessary to their activation. We focused on the intracellular signaling pathways vital to cell growth, differentiation and apoptosis including transcription factor families: activator protein 1 (AP1), nuclear factor (NFκB), signal transducer and activator of transcription (STAT), cAMP response element-binding protein (CREB) and Sp/NF-Y, with a special insight into the tissue specific cyclin representation.
Collapse
Affiliation(s)
- Jan Pawlonka
- Department of Internal Medicine and Endocrinology, Medical University of Warsaw, Warsaw
| | - Beata Rak
- Department of Internal Medicine and Endocrinology, Medical University of Warsaw, Warsaw; Department of Genomic Medicine, Medical University of Warsaw, Warsaw.
| | - Urszula Ambroziak
- Department of Internal Medicine and Endocrinology, Medical University of Warsaw, Warsaw
| |
Collapse
|
3
|
Ishikawa C, Mori N. The role of CUDC-907, a dual phosphoinositide-3 kinase and histone deacetylase inhibitor, in inhibiting proliferation of adult T-cell leukemia. Eur J Haematol 2020; 105:763-772. [PMID: 32780889 DOI: 10.1111/ejh.13508] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 08/06/2020] [Accepted: 08/07/2020] [Indexed: 12/11/2022]
Abstract
OBJECTIVES New effective therapeutic strategies for human T-cell leukemia virus type 1 (HTLV-1)-driven adult T-cell leukemia (ATL) are required because of resistance to chemotherapeutic agents. Here, we aimed to determine the therapeutic efficacy of a dual phosphoinositide 3 kinase (PI3K)/histone deacetylase (HDAC) inhibitor, CUDC-907. METHODS Cell viability, cell cycle progression, and apoptotic events were examined by WST-8 assay, flow cytometry, and Hoechst 33342 staining. Caspase activity was determined using Calorimetric Caspase Assay kits. Immunoblotting and electrophoretic mobility shift assay were used to assess the intracellular signaling cascades. RESULTS The combination of PI3K inhibitor BKM120 and HDAC inhibitor LBH589 resulted in a synergistic cytotoxic effect in HTLV-1-infected T cells. CUDC-907 was more efficacious than BKM120 and LBH589. It induced G1 cell cycle arrest with downregulation of cyclin D1/D2, CDK4/6, c-Myc, and phosphorylated retinoblastoma protein expression. Apoptosis was induced via caspase-3/8/9 activation along with downregulation of Bcl-XL , Bcl-2, XIAP, survivin, and cIAP1/2, and upregulation of Bax and Bak. Histone H3 acetylation, H2AX activation, Hsp27 phosphorylation, and Hsp70 and Hsp27 upregulation were observed after treatment. CUDC-907 suppressed Akt, NF-κB, and AP-1 by downregulating phosphorylated and/or total Akt, IKKα/β, RelA, JunB, and JunD. CONCLUSION CUDC-907 may be a potential therapeutic agent for ATL.
Collapse
Affiliation(s)
- Chie Ishikawa
- Department of Microbiology and Oncology, Graduate School of Medicine, University of the Ryukyus, Nishihara, Okinawa, Japan.,Division of Health Sciences, Transdisciplinary Research Organization for Subtropics and Island Studies, University of the Ryukyus, Nishihara, Okinawa, Japan
| | - Naoki Mori
- Department of Microbiology and Oncology, Graduate School of Medicine, University of the Ryukyus, Nishihara, Okinawa, Japan
| |
Collapse
|
4
|
Ishikawa C, Mori N. MALT-1 as a novel therapeutic target for adult T-cell leukemia. Eur J Haematol 2020; 105:460-467. [PMID: 32574386 DOI: 10.1111/ejh.13467] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 06/04/2020] [Accepted: 06/08/2020] [Indexed: 12/15/2022]
Abstract
OBJECTIVES T-cell receptor (TCR) signaling-induced activation of NF-κB requires assembly of the CARD11-BCL10-MALT-1 complex and IκB kinase (IKK). Gain-of-function alterations in this component of the TCR/NF-κB pathway are associated with the development of HTLV-1-driven adult T-cell leukemia (ATL). We aimed to determine whether inhibition of MALT-1-mediated NF-κB activation could have anti-ATL activity. METHODS RT-PCR, immunoblotting, and electrophoretic mobility shift assays were performed to assess expression levels of MALT-1 and the intracellular signaling cascades. Cell proliferation, cell cycle progression, and apoptotic events were examined using WST-8 assays, flow cytometry, and Hoechst 33342 staining. RESULTS MALT-1 expression was upregulated in ATL-derived T-cell lines compared to that in normal PBMCs and uninfected or HTLV-1-transformed T-cell lines. Targeting MALT-1 with siRNA decreased cell proliferation. A MALT-1 inhibitor (MI-2) suppressed cleavage of the MALT-1-target protein, CYLD, and inhibited proliferation via G1 phase arrest. MI-2 induced apoptosis through caspase-3/8/9 activation and inhibited the phosphorylation of IKKα/β and IκBα, resulting in the accumulation of IκBα and suppression of NF-κB-DNA binding. Additionally, MI-2 inhibited the expression of apoptosis- and cell cycle-related proteins regulated by NF-κB. CONCLUSIONS MALT-1 plays an important regulatory role in NF-κB signaling during ATL-genesis, and targeting MALT-1 is a promising therapeutic strategy for this disease.
Collapse
Affiliation(s)
- Chie Ishikawa
- Department of Microbiology and Oncology, Graduate School of Medicine, University of the Ryukyus, Nishihara, Japan.,Division of Health Sciences, Transdisciplinary Research Organization for Subtropics and Island Studies, University of the Ryukyus, Nishihara, Japan
| | - Naoki Mori
- Department of Microbiology and Oncology, Graduate School of Medicine, University of the Ryukyus, Nishihara, Japan
| |
Collapse
|
5
|
Fochi S, Ciminale V, Trabetti E, Bertazzoni U, D’Agostino DM, Zipeto D, Romanelli MG. NF-κB and MicroRNA Deregulation Mediated by HTLV-1 Tax and HBZ. Pathogens 2019; 8:pathogens8040290. [PMID: 31835460 PMCID: PMC6963194 DOI: 10.3390/pathogens8040290] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Revised: 11/27/2019] [Accepted: 12/06/2019] [Indexed: 12/17/2022] Open
Abstract
The risk of developing adult T-cell leukemia/lymphoma (ATLL) in individuals infected with human T-cell lymphotropic virus 1 (HTLV-1) is about 3–5%. The mechanisms by which the virus triggers this aggressive cancer are still an area of intensive investigation. The viral protein Tax-1, together with additional regulatory proteins, in particular HTLV-1 basic leucine zipper factor (HBZ), are recognized as relevant viral factors required for both viral replication and transformation of infected cells. Tax-1 deregulates several cellular pathways affecting the cell cycle, survival, and proliferation. The effects of Tax-1 on the NF-κB pathway have been thoroughly studied. Recent studies also revealed the impact of Tax-1 and HBZ on microRNA expression. In this review, we summarize the recent progress in understanding the contribution of HTLV-1 Tax- and HBZ-mediated deregulation of NF-κB and the microRNA regulatory network to HTLV-1 pathogenesis.
Collapse
Affiliation(s)
- Stefania Fochi
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biology and Genetics, University of Verona, 37134 Verona, Italy; (S.F.); (E.T.); (U.B.); (D.Z.)
| | - Vincenzo Ciminale
- Department of Surgery, Oncology and Gastroenterology, University of Padua, 35128 Padua, Italy;
- Veneto Institute of Oncology IOV-IRCCS, 35128 Padua, Italy
| | - Elisabetta Trabetti
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biology and Genetics, University of Verona, 37134 Verona, Italy; (S.F.); (E.T.); (U.B.); (D.Z.)
| | - Umberto Bertazzoni
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biology and Genetics, University of Verona, 37134 Verona, Italy; (S.F.); (E.T.); (U.B.); (D.Z.)
| | | | - Donato Zipeto
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biology and Genetics, University of Verona, 37134 Verona, Italy; (S.F.); (E.T.); (U.B.); (D.Z.)
| | - Maria Grazia Romanelli
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biology and Genetics, University of Verona, 37134 Verona, Italy; (S.F.); (E.T.); (U.B.); (D.Z.)
- Correspondence:
| |
Collapse
|
6
|
Ma Y, Zheng S, Wang Y, Zang W, Li M, Wang N, Li P, Jin J, Dong Z, Zhao G. The HTLV-1 HBZ protein inhibits cyclin D1 expression through interacting with the cellular transcription factor CREB. Mol Biol Rep 2013; 40:5967-75. [PMID: 24065533 DOI: 10.1007/s11033-013-2706-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 09/14/2013] [Indexed: 10/26/2022]
Abstract
Human T cell leukemia virus type 1 (HTLV-1) is an oncogenic retrovirus that can cause adult T-cell leukemia (ATL) and other diseases. The HTLV-1 bZIP factor (HBZ), which is encoded by an mRNA of the opposite polarity of the viral genomic RNA, interacts with several transcription factors and is involved in T cell proliferation, viral gene transcription and cellular transformation. Cyclin D1 is a pivotal regulatory protein involved in cell cycle progression, and its depressed expression correlates with cell cycle prolongation or arrested at the G1/S transition. In our present study, we observed that HBZ expression suppressed cyclin D1 level. To investigate the role of HBZ on cyclin D1 depression, we transduced HBZ with lentivirus vector into 293T cells, CEM cells and Jurkat cells. The results of Western blot, RT-PCR and luciferase assays showed that transcriptional activity of the cyclin D1 promoter was suppressed by the bZIP domain of HBZ (HBZ-bZIP) through cyclic AMP response element (CRE) site. Immunoprecipitation and GST pull-down assays showed the binding of HBZ-bZIP to CRE-binding protein (CREB), which confirmed that the cyclin D1 promoter activity inhibition via the CRE-site was mediated by HBZ-bZIP. The results suggested that HBZ suppressed cyclin D1 transcription through interactions with CREB and along with other viral protein, HBZ may play a causal role for leukemogenesis.
Collapse
Affiliation(s)
- Yunyun Ma
- College of Basic Medical Sciences, Zhengzhou University, Zhengzhou, Henan, China
| | | | | | | | | | | | | | | | | | | |
Collapse
|
7
|
A novel function of RNAs arising from the long terminal repeat of human endogenous retrovirus 9 in cell cycle arrest. J Virol 2012; 87:25-36. [PMID: 23097441 DOI: 10.1128/jvi.01648-12] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The human genome contains approximately 50 copies of the replication-defective human endogenous retrovirus 9 (ERV-9) and thousands of copies of its solitary long term repeat (sLTR) element. While some sLTRs are located upstream of critical genes and have enhancer activity, other sLTRs are located within introns and may be transcribed as RNAs. We found that intronic RNAs arising from U3 sLTRs of ERV-9 were expressed as both sense (S) and antisense (AS) transcripts in all human cells tested but that expression levels differed in malignant versus nonmalignant cells. In nonmalignant cells, AS was expressed at higher levels than S and at higher levels than in malignant cells; in malignant cells, AS was expressed at amounts equivalent to those of S RNA. Critically, U3 AS RNA was found to physically bind to key transcription factors for cellular proliferation, including NF-Y, p53, and sp1, indicating that such RNA transcripts may function as decoy targets or traps for NF-Y and thus inhibit the growth of human cancer cells. Indeed, short U3 oligodeoxynucleotides (ODNs) based on these RNA sequences ably inhibited proliferation of cancer cell lines driven by cyclins B1/B2, the gene targets of NF-Y.
Collapse
|
8
|
Arainga M, Murakami H, Aida Y. Visualizing spatiotemporal dynamics of apoptosis after G1 arrest by human T cell leukemia virus type 1 Tax and insights into gene expression changes using microarray-based gene expression analysis. BMC Genomics 2012; 13:275. [PMID: 22726420 PMCID: PMC3537563 DOI: 10.1186/1471-2164-13-275] [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: 03/06/2012] [Accepted: 06/07/2012] [Indexed: 12/31/2022] Open
Abstract
Background Human T cell leukemia virus type 1 (HTLV-1) Tax is a potent activator of viral and cellular gene expression that interacts with a number of cellular proteins. Many reports show that Tax is capable of regulating cell cycle progression and apoptosis both positively and negatively. However, it still remains to understand why the Tax oncoprotein induces cell cycle arrest and apoptosis, or whether Tax-induced apoptosis is dependent upon its ability to induce G1 arrest. The present study used time-lapse imaging to explore the spatiotemporal patterns of cell cycle dynamics in Tax-expressing HeLa cells containing the fluorescent ubiquitination-based cell cycle indicator, Fucci2. A large-scale host cell gene profiling approach was also used to identify the genes involved in Tax-mediated cell signaling events related to cellular proliferation and apoptosis. Results Tax-expressing apoptotic cells showed a rounded morphology and detached from the culture dish after cell cycle arrest at the G1 phase. Thus, it appears that Tax induces apoptosis through pathways identical to those involved in G1 arrest. To elucidate the mechanism(s) by which Tax induces cell cycle arrest and apoptosis, regulation of host cellular genes by Tax was analyzed using a microarray containing approximately 18,400 human mRNA transcripts. Seventeen genes related to cell cycle regulation were identified as being up or downregulated > 2.0-fold in Tax-expressing cells. Several genes, including SMAD3, JUN, GADD45B, DUSP1 and IL8, were involved in cellular proliferation, responses to cellular stress and DNA damage, or inflammation and immune responses. Additionally, 23 pro- and anti-apoptotic genes were deregulated by Tax, including TNFAIP3, TNFRS9, BIRC3 and IL6. Furthermore, the kinetics of IL8, SMAD3, CDKN1A, GADD45A, GADD45B and IL6 expression were altered following the induction of Tax, and correlated closely with the morphological changes observed by time-lapse imaging. Conclusions Taken together, the results of this study permit a greater understanding of the biological events affected by HTLV-1 Tax, particularly the regulation of cellular proliferation and apoptosis. Importantly, this study is the first to demonstrate the dynamics of morphological changes during Tax-induced apoptosis after cell cycle arrest at the G1 phase.
Collapse
Affiliation(s)
- Mariluz Arainga
- Viral Infectious Diseases Unit, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | | | | |
Collapse
|
9
|
Abstract
Human T-cell lymphotropic virus type 1 (HTLV-1) is the etiological agent of adult T-cell leukemia/lymphoma (ATL), whereas the highly related HTLV-2 is not associated with ATL or other cancers. In addition to ATL leukemogenesis, studies of the HTLV viruses also provide an exceptional model for understanding basic pathogenic mechanisms of virus-host interactions and human oncogenesis. Accumulating evidence suggests that the viral regulatory protein Tax and host inflammatory transcription factor NF-κB are largely responsible for the different pathogenic potentials of HTLV-1 and HTLV-2. Here, we discuss the molecular mechanisms of HTLV-1 oncogenic pathogenesis with a focus on the interplay between the Tax oncoprotein and NF-κB pro-oncogenic signaling. We also outline some of the most intriguing and outstanding questions in the fields of HTLV and NF-κB. Answers to those questions will greatly advance our understanding of ATL leukemogenesis and other NF-κB-associated tumorigenesis and will help us design personalized cancer therapies.
Collapse
|
10
|
Markholt S, Grøndahl M, Ernst E, Andersen CY, Ernst E, Lykke-Hartmann K. Global gene analysis of oocytes from early stages in human folliculogenesis shows high expression of novel genes in reproduction. ACTA ACUST UNITED AC 2012; 18:96-110. [DOI: 10.1093/molehr/gar083] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
|
11
|
Kim YM, Geiger TR, Egan DI, Sharma N, Nyborg JK. The HTLV-1 tax protein cooperates with phosphorylated CREB, TORC2 and p300 to activate CRE-dependent cyclin D1 transcription. Oncogene 2010; 29:2142-52. [PMID: 20101207 PMCID: PMC2851846 DOI: 10.1038/onc.2009.498] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Adult T-cell leukemia/lymphoma is a fatal malignancy etiologically linked to infection with the human T-cell leukemia virus (HTLV-1). The virally-encoded oncoprotein Tax activates transcription of HTLV-1 and cellular genes by cooperating with cellular transcription factors. Cyclin D1 is a pivotal regulator of cell cycle progression, and increased expression strongly correlates with malignant transformation. Here, we characterize the mechanism of Tax transactivation of cyclin D1. We find that cyclin D1 transcript levels are elevated in HTLV-1 infected cells and that Tax physically associates with the cyclin D1 gene in vivo. Tax binds the cyclin D1 promoter-proximal cyclic AMP response element (CRE) in the presence of phosphorylated CREB (pCREB) in vitro, and together the Tax/pCREB complex recruits the cellular coactivator p300 to the promoter via this unconventional Tax-responsive element. We further show that Transducer of Regulated CREB 2 (TORC2) cooperates with Tax to further enhance p300 recruitment to the cyclin D1 promoter in vitro, consistent with enhanced cyclin D1 expression in the presence of Tax and TORC2. Together, our findings support a model in which Tax-induced accumulation of cyclin D1 shortens the G1 phase of the cell cycle, promotes mitotic replication of the virus, and drives selection and expansion of malignant T-cells.
Collapse
Affiliation(s)
- Y-M Kim
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523-1870, USA
| | | | | | | | | |
Collapse
|
12
|
The proto-oncogene Bcl3, induced by Tax, represses Tax-mediated transcription via p300 displacement from the human T-cell leukemia virus type 1 promoter. J Virol 2008; 82:11939-47. [PMID: 18815299 DOI: 10.1128/jvi.01356-08] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The etiology of human T-cell leukemia virus type 1 (HTLV-1)-induced adult T-cell leukemia is linked to the expression of the viral oncoprotein Tax. Although the mechanism of retroviral transformation is unknown, Tax interferes with fundamental cellular processes, including proliferation and apoptosis, and these events may directly link Tax to early steps in malignant progression. In this study, we examined the interplay between Tax and the potent proto-oncogene B-cell chronic leukemia protein 3 (Bcl3). Bcl3 is a critical regulator of cell survival and proliferation and is overexpressed in HTLV-1-infected cells. We found that Tax induced Bcl3 expression through stimulation of the NF-kappaB pathway. An intronic NF-kappaB binding site within the Bcl3 gene served as the primary target of Tax-induced NF-kappaB activation. We next considered the consequence of Bcl3 overexpression on Tax function. Interestingly, we found that Bcl3 formed a stable complex with Tax and that this complex potently inhibited Tax-dependent HTLV-1 transcription. Importantly, Bcl3 associated with the HTLV-1 promoter in a Tax-dependent manner and inhibited the binding of the critical cellular coactivator p300. The conserved ankyrin repeat domain of Bcl3 mediated both Tax binding and inhibition of p300 recruitment to the HTLV-1 promoter. Together, these data suggest that Tax-induced Bcl3 overexpression benefits the virus in two important ways. First, Bcl3 may promote cell division and thus clonal proliferation of the virus. Second, Bcl3 may attenuate virion production, facilitating immune evasion. One consequence of this regulatory loop may be Bcl3-induced malignant transformation of the host cell.
Collapse
|
13
|
Kawakami H, Tomita M, Okudaira T, Ishikawa C, Matsuda T, Tanaka Y, Nakazato T, Taira N, Ohshiro K, Mori N. Inhibition of heat shock protein-90 modulates multiple functions required for survival of human T-cell leukemia virus type I-infected T-cell lines and adult T-cell leukemia cells. Int J Cancer 2007; 120:1811-20. [PMID: 17230513 DOI: 10.1002/ijc.22403] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The molecular chaperone Hsp90 is involved in the stabilization and conformational maturation of many signaling proteins that are deregulated in cancers. The geldanamycin derivative 17-AAG is currently tested in clinical trials and known to inhibit the function of Hsp90 and promote the proteasomal degradation of its misfolded client proteins. ATL is a fatal malignancy of T lymphocytes caused by HTLV-I infection and remains incurable. Since Hsp90 is overexpressed in HTLV-I-infected T-cell lines and primary ATL cells, we analyzed the effects of 17-AAG on cell survival, apoptosis and expression of signal transduction proteins. HTLV-I-infected T-cell lines and primary ATL cells were significantly more sensitive to 17-AAG in cell survival assays than normal PBMCs. 17-AAG induced the inhibition of cell cycle and apoptosis. These effects could be mediated by inactivation of NF-kappaB, AP-1 and PI3K/Akt pathways, as well as reduction of expression of proteins involved in the G1-S cell cycle transition and apoptosis. Proteasome inhibition interfered with 17-AAG-mediated signaling proteins depletion. Collectively, our results indicate that 17-AAG suppresses ATL cell survival through, at least in part, destabilization of several client proteins and suggest that 17-AAG is a potentially useful chemotherapeutic agent for ATL.
Collapse
Affiliation(s)
- Hirochika Kawakami
- Division of Molecular Virology and Oncology, Graduate School of Medicine, University of the Ryukyus, Nishihara, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
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]
|
15
|
Hiscott J, Nguyen TLA, Arguello M, Nakhaei P, Paz S. Manipulation of the nuclear factor-kappaB pathway and the innate immune response by viruses. Oncogene 2006; 25:6844-67. [PMID: 17072332 PMCID: PMC7100320 DOI: 10.1038/sj.onc.1209941] [Citation(s) in RCA: 206] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Viral and microbial constituents contain specific motifs or pathogen-associated molecular patterns (PAMPs) that are recognized by cell surface- and endosome-associated Toll-like receptors (TLRs). In addition, intracellular viral double-stranded RNA is detected by two recently characterized DExD/H box RNA helicases, RIG-I and Mda-5. Both TLR-dependent and -independent pathways engage the IkappaB kinase (IKK) complex and related kinases TBK-1 and IKKvarepsilon. Activation of the nuclear factor kappaB (NF-kappaB) and interferon regulatory factor (IRF) transcription factor pathways are essential immediate early steps of immune activation; as a result, both pathways represent prime candidates for viral interference. Many viruses have developed strategies to manipulate NF-kappaB signaling through the use of multifunctional viral proteins that target the host innate immune response pathways. This review discusses three rapidly evolving areas of research on viral pathogenesis: the recognition and signaling in response to virus infection through TLR-dependent and -independent mechanisms, the involvement of NF-kappaB in the host innate immune response and the multitude of strategies used by different viruses to short circuit the NF-kappaB pathway.
Collapse
Affiliation(s)
- J Hiscott
- Terry Fox Molecular Oncology Group, Lady Davis Institute for Medical Research, McGill University, Montreal, Canada.
| | | | | | | | | |
Collapse
|
16
|
Sanda T, Asamitsu K, Ogura H, Iida S, Utsunomiya A, Ueda R, Okamoto T. Induction of cell death in adult T-cell leukemia cells by a novel IkappaB kinase inhibitor. Leukemia 2006; 20:590-8. [PMID: 16453001 DOI: 10.1038/sj.leu.2404129] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
NF-kappaB is constitutively activated in adult T-cell leukemia (ATL) and is considered responsible for cell growth and prevention of cell death. In this study, we demonstrate that NF-kappaB is constitutively activated in various HTLV-1-infected T-cell lines and ATL-derived cell lines irrespectively of Tax expression as evidenced by the phosphorylation of IkappaBalpha and p65 subunit of NF-kappaB, activation of NF-kappaB DNA binding, and upregulation of various target genes including bcl-xL, bcl-2, XIAP, c-IAP1, survivin, cyclinD1, ICAM-1 and VCAM-1. The effects of a novel IkappaB kinase (IKK) inhibitor, 2-amino-6-[2-(cyclopropylmethoxy)-6-hydroxyphenyl]-4-piperidin-4-yl nicotinonitrile (ACHP), were examined on cell growth of these cell lines and fresh ATL leukemic cells. We found that ACHP could inhibit the phosphorylation of IkappaBalpha and p65, as well as NF-kappaB DNA-binding, associated with downregulation of the NF-kappaB target genes and induce cell growth arrest and apoptosis in these cells. When Tax-active and Tax-inactive cell lines were compared, ACHP could preferentially inhibit cell growth of Tax-active cells. Moreover, ACHP exhibited strong apoptosis-inducing activity in fresh ATL cells. These findings indicate that ACHP and its derivatives are effective in inducing ATL cell death and thus feasible candidates for the treatment of ATL.
Collapse
Affiliation(s)
- T Sanda
- Department of Molecular and Cellular Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | | | | | | | | | | | | |
Collapse
|
17
|
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.
Collapse
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
| |
Collapse
|
18
|
Karrman K, Andersson A, Björgvinsdóttir H, Strömbeck B, Lassen C, Olofsson T, Nguyen-Khac F, Berger R, Bernard O, Fioretos T, Johansson B. Deregulation of cyclin D2 by juxtaposition with T-cell receptor alpha/delta locus in t(12;14)(p13;q11)-positive childhood T-cell acute lymphoblastic leukemia. Eur J Haematol 2006; 77:27-34. [PMID: 16548914 DOI: 10.1111/j.0902-4441.2006.t01-1-ejh2553.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
OBJECTIVES The t(12;14)(p13;q11)--a recurrent translocation in childhood T-cell acute lymphoblastic leukemia (T-ALL)--has very recently been molecularly characterized in one case, which displayed overexpression of the cyclin D2 gene (CCND2). PATIENTS AND METHODS We have characterized two pediatric t(12;14)-positive T-ALLs using fluorescence in situ hybridization (FISH), cDNA microarray, and real-time polymerase chain reaction (PCR). RESULTS FISH revealed breakpoints (BPs) in the T-cell receptor alpha/delta locus (14q11) and in the vicinity of the CCND2 gene at 12p13. To investigate the expression of genes in 12p13, cDNA microarray analysis was performed. Expression data for eight genes, including CCND2, surrounding the 12p BP were compared with those in other T-ALLs. The t(12;14)-positive T-ALL displayed an increased expression of CCND2 compared to the controls, whereas the expression of the other genes was similar in all T-ALLs. Expression of CCND2 and two additional genes (PARP11 and FGF23), close to the 12p BP, was investigated with real-time PCR of the two t(12;14)-positive cases and four controls. Neither PARP11 nor FGF23 displayed expression differences among the T-ALLs, whereas CCND2 was clearly overexpressed in both t(12;14)-positive cases as compared to the mean expression level in the controls. CONCLUSION We have confirmed, in two additional cases, that the recurrent T-ALL-associated t(12;14) results in overexpression of cyclin D2. The t(12;14) is the first neoplasia-associated translocation shown to result in overexpression of cyclin D2. Furthermore, it is the first example of a T-cell neoplasm with a targeted deregulation of a member of a cyclin-encoding gene family.
Collapse
MESH Headings
- Adolescent
- Chromosomes, Human, Pair 12
- Chromosomes, Human, Pair 14
- Cyclin D2
- Cyclins/genetics
- Cyclins/metabolism
- Female
- Fibroblast Growth Factor-23
- Gene Expression Regulation, Neoplastic
- Humans
- In Situ Hybridization, Fluorescence
- Infant
- Male
- Polymerase Chain Reaction
- Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics
- Receptors, Antigen, T-Cell, alpha-beta/genetics
- Receptors, Antigen, T-Cell, alpha-beta/metabolism
- Receptors, Antigen, T-Cell, gamma-delta/genetics
- Receptors, Antigen, T-Cell, gamma-delta/metabolism
- Translocation, Genetic
Collapse
Affiliation(s)
- Kristina Karrman
- Department of Clinical Genetics, University Hospital, Lund, Sweden.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Okudaira T, Tomita M, Uchihara JN, Matsuda T, Ishikawa C, Kawakami H, Masuda M, Tanaka Y, Ohshiro K, Takasu N, Mori N. NIK-333 inhibits growth of human T-cell leukemia virus type I-infected T-cell lines and adult T-cell leukemia cells in association with blockade of nuclear factor-kappaB signal pathway. Mol Cancer Ther 2006; 5:704-12. [PMID: 16546985 DOI: 10.1158/1535-7163.mct-05-0434] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Adult T-cell leukemia (ATL) is caused by human T-cell leukemia virus type I (HTLV-I) and remains incurable. NIK-333, a novel synthetic retinoid, prevents the recurrence of human hepatoma after surgical resection of primary tumors. We explored the effects of NIK-333 on HTLV-I-infected T-cell lines and ATL cells. NIK-333 inhibited cell proliferation, induced G1 arrest, and resulted in massive apoptosis in all tested HTLV-I-infected T-cell lines and ATL cells, whereas little effect was observed on normal peripheral blood mononuclear cells. NIK-333 treatment decreases the levels of cyclin D1, cyclin D2, cIAP2, and XIAP proteins. Further analysis showed that NIK-333 inactivated nuclear factor-kappaB in HTLV-I-infected T-cell lines. In animal studies, treatment with NIK-333 (100 mg/kg given orally every other day) produced partial inhibition of growth of tumors of a HTLV-I-infected T-cell line transplanted s.c. in severe combined immunodeficient mice. Our results indicate that NIK-333 is a potentially useful therapeutic agent for patients with ATL.
Collapse
Affiliation(s)
- Taeko Okudaira
- Division of Molecular Virology and Oncology, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa 903-0215, Japan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Tomita M, Kawakami H, Uchihara JN, Okudaira T, Masuda M, Matsuda T, Tanaka Y, Ohshiro K, Mori N. Inhibition of constitutively active Jak-Stat pathway suppresses cell growth of human T-cell leukemia virus type 1-infected T-cell lines and primary adult T-cell leukemia cells. Retrovirology 2006; 3:22. [PMID: 16603085 PMCID: PMC1483830 DOI: 10.1186/1742-4690-3-22] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2005] [Accepted: 04/09/2006] [Indexed: 01/02/2023] Open
Abstract
Background Human T-cell leukemia virus type 1 (HTLV-1), the etiologic agent for adult T-cell leukemia (ATL), induces cytokine-independent proliferation of T-cells, associated with the acquisition of constitutive activation of Janus kinases (Jak) and signal transducers and activators of transcription (Stat) proteins. Our purposes in this study were to determine whether activation of Jak-Stat pathway is responsible for the proliferation and survival of ATL cells, and to explore mechanisms by which inhibition of Jak-Stat pathway kills ATL cells. Results Constitutive activation of Stat3 and Stat5 was observed in HTLV-1-infected T-cell lines and primary ATL cells, but not in HTLV-1-negative T-cell lines. Using AG490, a Jak-specific inhibitor, we demonstrated that the activation of Stat3 and Stat5 was mediated by the constitutive phosphorylation of Jak proteins. AG490 inhibited the growth of HTLV-1-infected T-cell lines and primary ATL cells by inducing G1 cell-cycle arrest mediated by altering the expression of cyclin D2, Cdk4, p53, p21, Pim-1 and c-Myc, and by apoptosis mediated by the reduced expression of c-IAP2, XIAP, survivin and Bcl-2. Importantly, AG490 did not inhibit the growth of normal peripheral blood mononuclear cells. Conclusion Our results indicate that activation of Jak-Stat pathway is responsible for the proliferation and survival of ATL cells. Inhibition of this pathway may provide a new approach for the treatment of ATL.
Collapse
Affiliation(s)
- Mariko Tomita
- Division of Molecular Virology and Oncology, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa 903-0215, Japan
| | - Hirochika Kawakami
- Division of Molecular Virology and Oncology, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa 903-0215, Japan
| | - Jun-nosuke Uchihara
- Division of Molecular Virology and Oncology, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa 903-0215, Japan
- Division of Endocrinology and Metabolism, Faculty of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa 903-0215, Japan
| | - Taeko Okudaira
- Division of Molecular Virology and Oncology, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa 903-0215, Japan
- Division of Endocrinology and Metabolism, Faculty of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa 903-0215, Japan
| | - Masato Masuda
- Division of Endocrinology and Metabolism, Faculty of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa 903-0215, Japan
| | - Takehiro Matsuda
- Division of Molecular Virology and Oncology, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa 903-0215, Japan
- Division of Child Health and Welfare, Faculty of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa 903-0215, Japan
| | - Yuetsu Tanaka
- Division of Immunology, Faculty of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa 903-0215, Japan
| | - Kazuiku Ohshiro
- Department of Internal Medicine, Naha Prefectural Hospital, 1-3-1 Yogi, Naha, Okinawa 902-8531, Japan
| | - Naoki Mori
- Division of Molecular Virology and Oncology, Graduate School of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa 903-0215, Japan
| |
Collapse
|
21
|
Tomita M, Kawakami H, Uchihara JN, Okudaira T, Masuda M, Takasu N, Matsuda T, Ohta T, Tanaka Y, Ohshiro K, Mori N. Curcumin (diferuloylmethane) inhibits constitutive active NF-kappaB, leading to suppression of cell growth of human T-cell leukemia virus type I-infected T-cell lines and primary adult T-cell leukemia cells. Int J Cancer 2006; 118:765-72. [PMID: 16106398 DOI: 10.1002/ijc.21389] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Adult T-cell leukemia (ATL) is a fatal malignancy of T lymphocytes caused by infection with human T-cell leukemia virus type I (HTLV-I) and remains incurable. Curcumin (diferuloylmethane), the major pigment of the spice turmeric, can be potentially effective by promoting cell apoptosis. Here we examined whether curcumin is effective in the treatment of ATL. Curcumin prevented cell growth of HTLV-I-infected T-cell lines and primary ATL cells but not of normal peripheral blood mononuclear cells. Curcumin induced cell cycle arrest by reducing the expression of cyclin D1, Cdk1 and Cdc25C and apoptosis by reducing the expression of XIAP and survivin. Most of these genes are known to be regulated by NF-kappaB, which plays a critical role in oncogenesis by HTLV-I. Curcumin suppressed constitutive active NF-kappaB of HTLV-I-infected T-cell lines and primary ATL cells by inhibiting phosphorylation of IkappaBalpha. Curcumin also inhibited Tax-induced NF-kappaB transcriptional activity. However, curcumin-induced suppression of cell growth did not correlate with Tax expression level. Curcumin inhibited the growth of HTLV-I-infected T-cell tumors implanted subcutaneously in SCID mice. Our results indicate that curcumin has tumor-suppressive activity against ATL.
Collapse
Affiliation(s)
- Mariko Tomita
- Division of Molecular Virology and Oncology, Graduate School of Medicine, University of the Ryukyus, Nishihara, Japan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Abstract
HTLV-1 and HTLV-2 are highly related complex retroviruses that have been studied intensely for nearly three decades because of their association with neoplasia, neuropathology, and/or their capacity to transform primary human T lymphocytes. The study of HTLV also represents an attractive model that has allowed investigators to dissect the mechanism of various cellular processes, several of which may be critical steps in HTLV-mediated pathogenesis. Both HTLV-1 and HTLV-2 can efficiently immortalize and transform T lymphocytes in cell culture and persist in infected individuals or experimental animals. However, the clinical manifestations of these two viruses differ significantly. HTLV-1 is associated with adult T-cell leukemia (ATL) and a variety of immune-mediated disorders including the chronic neurological disease termed HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). In contrast, HTLV-2 is much less pathogenic with reports of only a few cases of variant hairy cell leukemia and neurological disease associated with infection. The limited number of individuals shown to harbor HTLV-2 in association with specific diseases has, to date, precluded convincing epidemiological demonstration of a definitive etiologic role of HTLV-2 in human disease. Therefore, it has become clear that comparative studies designed to elucidate the mechanisms by which HTLV-1 and HTLV-2 determine distinct outcomes are likely to provide fundamental insights into the initiation of multistep leukemogenesis.
Collapse
Affiliation(s)
- Gerold Feuer
- Department of Microbiology and Immunology, SUNY Upstate Medical University, Syracuse, New York 13210, USA
| | | |
Collapse
|
23
|
Bal HP, Cheng J, Murakami A, Tallarico ASC, Wang W, Zhou D, Vasicek TJ, Marasco WA. GITR overexpression on CD4+CD25+ HTLV-1 transformed cells: detection by massively parallel signature sequencing. Biochem Biophys Res Commun 2005; 332:569-84. [PMID: 15896717 DOI: 10.1016/j.bbrc.2005.04.162] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2005] [Accepted: 04/26/2005] [Indexed: 10/25/2022]
Abstract
HTLV-I is the etiologic agent of adult T-cell leukemia (ATL), a fatal T-cell malignancy that is associated with profound immunosuppression. In this study, comprehensive gene expression profiling was performed using massively parallel signature sequencing (MPSS) to investigate virus-host interactions in acutely HTLV-1 transformed cells. The analysis revealed the modulation of numerous genes across different functional classes, many of which have not been previously implicated in HTLV-1 transformation or ATL. Differences in the transcriptomes of transformed cell lines were observed that have provided clues on how different clonal populations of cells respond to virus transformation. Quantitation of HTLV-1 transcription was possible, thus making MPSS a useful tool to study emerging pathogens and unknown microbial causes of human diseases. Importantly, overexpression of GITR, an activation marker that has not been previously reported to be upregulated by HTLV-1-infection or in transformed/leukemic cells and that is associated with the suppressor phenotype of CD4+CD25+ regulatory T-cells (Tregs), was also observed. The deep and quantitative gene expression profile generated by MPSS should provide additional leads for discovery research that can be applied to better understand the pathobiology of HTLV-1 transformation and ATL as well as to developing new therapies.
Collapse
Affiliation(s)
- Harshawardhan P Bal
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Harvard Medical School, 44 Binney St., Boston, MA 02115, USA
| | | | | | | | | | | | | | | |
Collapse
|
24
|
Tsubata C, Higuchi M, Takahashi M, Oie M, Tanaka Y, Gejyo F, Fujii M. PDZ domain-binding motif of human T-cell leukemia virus type 1 Tax oncoprotein is essential for the interleukin 2 independent growth induction of a T-cell line. Retrovirology 2005; 2:46. [PMID: 16042787 PMCID: PMC1199618 DOI: 10.1186/1742-4690-2-46] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2005] [Accepted: 07/23/2005] [Indexed: 01/16/2023] Open
Abstract
Background Human T-cell leukemia virus type 1 (HTLV-1) is the etiologic agent of adult T-cell leukemia (ATL), whereas HTLV type 2 (HTLV-2), is not associated with ATL or any other leukemia. HTLV-1 encodes the transforming gene tax1, whose expression in an interleukin (IL)-2-dependent T-cell line (CTLL-2) induces IL-2-independent growth. Results In this study, we demonstrated that IL-2-independent growth induction by Tax1 was abrogated by mutations of the PDZ domain-binding motif (PBM) at the Tax1 C-terminus. HTLV-2 Tax2, which shares 75% amino acid identity with Tax1 but does not have a PBM, was not able to induce IL-2-independent growth of CTLL-2. Conclusion Our results suggest that Tax1, through interaction with PDZ domain protein(s) induces IL-2-independent growth, which may be a factor in multi-step leukemogenesis caused by HTLV-1.
Collapse
Affiliation(s)
- Chikako Tsubata
- Division of Virology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-Dori, Niigata 951-8510, Japan
- Division of Clinical Nephrology and Rheumatology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-Dori, Niigata 951-8510, Japan
| | - Masaya Higuchi
- Division of Virology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-Dori, Niigata 951-8510, Japan
| | - Masahiko Takahashi
- Division of Virology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-Dori, Niigata 951-8510, Japan
| | - Masayasu Oie
- Division of Virology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-Dori, Niigata 951-8510, Japan
| | - Yuetsu Tanaka
- Department of Infectious Disease and Immunology, Okinawa-Asia Research Center of Medical Science, Faculty of Medicine, University of the Ryukyus, Okinawa, Japan
| | - Fumitake Gejyo
- Division of Clinical Nephrology and Rheumatology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-Dori, Niigata 951-8510, Japan
| | - Masahiro Fujii
- Division of Virology, Niigata University Graduate School of Medical and Dental Sciences, 1-757 Asahimachi-Dori, Niigata 951-8510, Japan
| |
Collapse
|
25
|
Higuchi M, Matsuda T, Mori N, Yamada Y, Horie R, Watanabe T, Takahashi M, Oie M, Fujii M. Elevated expression of CD30 in adult T-cell leukemia cell lines: possible role in constitutive NF-kappaB activation. Retrovirology 2005; 2:29. [PMID: 15876358 PMCID: PMC1274245 DOI: 10.1186/1742-4690-2-29] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2005] [Accepted: 05/06/2005] [Indexed: 12/17/2022] Open
Abstract
Background Human T-cell leukemia virus type 1 (HTLV-1) is associated with the development of adult T-cell leukemia (ATL). HTLV-1 encoded Tax1 oncoprotein activates the transcription of genes involved in cell growth and anti-apoptosis through the NF-κB pathway, and is thought to play a critical role in the pathogenesis of ATL. While Tax1 expression is usually lost or minimal in ATL cells, these cells still show high constitutive NF-κB activity, indicating that genetic or epigenetic changes in ATL cells induce activation independent of Tax1. The aim of this study was to identify the molecules responsible for the constitutive activation of NF-κB in ATL cells using a retroviral functional cloning strategy. Results Using enhanced green fluorescent protein (EGFP) expression and blasticidin-resistance as selection markers, several retroviral cDNA clones exhibiting constitutive NF-κB activity in Rat-1 cells, including full-length CD30, were obtained from an ATL cell line. Exogenous stable expression of CD30 in Rat-1 cells constitutively activated NF-κB. Elevated expression of CD30 was identified in all ATL lines examined, and primary ATL cells from a small number of patients (8 out of 66 cases). Conclusion Elevated CD30 expression is considered one of the causes of constitutive NF-κB activation in ATL cells, and may be involved in ATL development.
Collapse
Affiliation(s)
- Masaya Higuchi
- Division of Virology, Niigata University Graduate School of Medical and Dental Sciences, Niigata 951-8510, Japan
| | - Takehiro Matsuda
- Division of Molecular Virology and Oncology, Faculty of Medicine, University of the Ryukyus, Nishihara, Okinawa 903-0215, Japan
| | - Naoki Mori
- Division of Molecular Virology and Oncology, Faculty of Medicine, University of the Ryukyus, Nishihara, Okinawa 903-0215, Japan
| | - Yasuaki Yamada
- Department of Laboratory Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 825-8501, Japan
| | - Ryouichi Horie
- Fourth Department of Internal Medicine, Faculty of Medicine, Kitasato University, Sagamihara, Kanagawa 228-8555, Japan
| | - Toshiki Watanabe
- Laboratory of Tumor Cell Biology, Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Minato-ku, Tokyo 108-109, Japan
| | - Masahiko Takahashi
- Division of Virology, Niigata University Graduate School of Medical and Dental Sciences, Niigata 951-8510, Japan
| | - Masayasu Oie
- Division of Virology, Niigata University Graduate School of Medical and Dental Sciences, Niigata 951-8510, Japan
| | - Masahiro Fujii
- Division of Virology, Niigata University Graduate School of Medical and Dental Sciences, Niigata 951-8510, Japan
| |
Collapse
|
26
|
Watanabe M, Dewan MZ, Okamura T, Sasaki M, Itoh K, Higashihara M, Mizoguchi H, Honda M, Sata T, Watanabe T, Yamamoto N, Umezawa K, Horie R. A novel NF-?B inhibitor DHMEQ selectively targets constitutive NF-?B activity and induces apoptosis of multiple myeloma cellsin vitro andin vivo. Int J Cancer 2005; 114:32-8. [PMID: 15523684 DOI: 10.1002/ijc.20688] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Multiple myeloma (MM) is a fatal lymphoid malignancy that is incurable with conventional modalities of chemotherapy. Strong and constitutive activation of nuclear factor kappa B (NF-kappaB) is a common characteristic of MM cells. In our study we successfully target NF-kappaB with a novel NF-kappaB inhibitor dehydroxymethylepoxyquinomycin (DHMEQ). DHMEQ completely abrogates constitutive NF-kappaB activity and induces apoptosis of MM cells, whereas control peripheral blood mononuclear cells (PBMC) are resistant to NF-kappaB inhibition and apoptosis by DHMEQ treatment. DHMEQ inhibition of NF-kappaB triggers activation of caspases 8 and 9, as well as G0/G1 cell cycle arrest accompanied by downregulation of antiapoptotic genes Bcl-XL and c-FLIP and cell cycle progression gene cyclins D1 and D2. DHMEQ-mediated inhibition of vascular endothelial growth factor (VEGF) production in MM cells raises the possibility that DHMEQ abrogates the autocrine VEGF loop and enhances its antitumor effects by inhibiting neovascularization in the bone marrow. Using an in vivo NOD/SCID/gammac(null) (NOG) mice model, we show that DHMEQ has a potent inhibitory effect on the growth of MM cells. Compared to other compounds having the potential to inhibit NF-kappaB, DHMEQ is a unique compound that blocks the translocation of NF-kappaB p65 into the nucleus and selectively targets NF-kappaB activated in tumor cells. Therefore, our study presents a new molecular target therapy in MM.
Collapse
Affiliation(s)
- Mariko Watanabe
- The Fourth Department of Internal Medicine, School of Medicine, Kitasato University, Kanagawa, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Hironaka N, Mochida K, Mori N, Maeda M, Yamamoto N, Yamaoka S. Tax-independent constitutive IkappaB kinase activation in adult T-cell leukemia cells. Neoplasia 2004; 6:266-78. [PMID: 15153339 PMCID: PMC1502096 DOI: 10.1593/neo.3388] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Adult T-cell leukemia (ATL) is a fatal T-cell malignancy that arises long after infection with human T-cell leukemia virus type I (HTLV-I). We reported previously that nuclear factor-kappaB (NF-kappaB) was constitutively activated in ATL cells, although expression of the viral proteins was barely detectable, including Tax, which was known to persistently activate NF-kappaB. Here we demonstrate that ATL cells that do not express detectable Tax protein exhibit constitutive IkappaB kinase (IKK) activity. Transfection studies revealed that a dominant-negative form of IKK1, and not of IKK2 or NF-kappaB essential modulator (NEMO), suppressed constitutive NF-kappaB activity in ATL cells. This IKK activity was accompanied by elevated expression of p52, suggesting that the recently described noncanonical pathway of NF-kappaB activation operates in ATL cells. We finally show that specific inhibition of NF-kappaB by a super-repressor form of IkappaBalpha (SR-IkappaBalpha) in HTLV-I-infected T cells results in cell death regardless of Tax expression, providing definitive evidence of an essential role for NF-kappaB in the survival of ATL cells. In conclusion, the IKK complex is constitutively activated in ATL cells through a cellular mechanism distinct from that of Tax-mediated IKK activation. Further elucidation of this cellular mechanism should contribute to establishing a rationale for treatment of ATL.
Collapse
Affiliation(s)
- Noriko Hironaka
- Department of Molecular Virology, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
- Research Laboratory of Minophagen Pharmaceutical Co., Ltd., Kanagawa, Japan
| | - Kanako Mochida
- Department of Molecular Virology, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - Naoki Mori
- Division of Molecular Virology and Oncology, Graduate School of Medicine, University of Ryukyus, Okinawa, Japan
| | - Michiyuki Maeda
- Laboratory of Animal Experiments for Regeneration, Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan
| | - Naoki Yamamoto
- Department of Molecular Virology, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| | - Shoji Yamaoka
- Department of Molecular Virology, Graduate School of Medicine, Tokyo Medical and Dental University, Tokyo, Japan
| |
Collapse
|
28
|
Wycuff DR, Yanites HL, Marriott SJ. Identification of a functional serum response element in the HTLV-I LTR. Virology 2004; 324:540-53. [PMID: 15207639 DOI: 10.1016/j.virol.2004.04.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2004] [Revised: 03/15/2004] [Accepted: 04/07/2004] [Indexed: 11/19/2022]
Abstract
In response to various mitogenic signals, serum response factor (SRF) activates cellular gene expression after binding to its cognate target sequence (CArG box) located within a serum response element (SRE). SRF is particularly important in T cell activation, and we now report that SRF activates basal transcription from the human T-cell leukemia virus-I (HTLV-I) long terminal repeat (LTR). A DNA element, with similarity to the consensus cellular CArG box found in the c-fos promoter centered approximately 120 base pairs upstream from the viral transcription start site, has been identified and named the vCArG box. SRF activation of gene expression from the LTR was localized to the vCArG box, and mutation of this site abolished SRF responsiveness. An oligonucleotide probe containing the vCArG box bound purified SRF, and a complex formed on this probe with nuclear extract was supershifted by anti-SRF antibody. Moreover, a biotinylated probe containing the vCArG box bound SRF in avidin-biotin pull-down assays. Quantitative binding analysis yielded nanomolar affinities for both the viral and cellular CArG boxes. Chromatin immunoprecipitation experiments demonstrated that SRF is resident on the HTLV-I LTR in vivo. These data identify a functional serum response element in the HTLV-I LTR and suggest that SRF may play an important role in regulating basal HTLV-I gene expression in early infection and reactivation from latency.
Collapse
Affiliation(s)
- Diane R Wycuff
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | | | | |
Collapse
|
29
|
Mori N, Matsuda T, Tadano M, Kinjo T, Yamada Y, Tsukasaki K, Ikeda S, Yamasaki Y, Tanaka Y, Ohta T, Iwamasa T, Tomonaga M, Yamamoto N. Apoptosis induced by the histone deacetylase inhibitor FR901228 in human T-cell leukemia virus type 1-infected T-cell lines and primary adult T-cell leukemia cells. J Virol 2004; 78:4582-90. [PMID: 15078940 PMCID: PMC387669 DOI: 10.1128/jvi.78.9.4582-4590.2004] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Inhibition of histone deacetylase (HDAC) activity induces growth arrest, differentiation, and, in certain cell types, apoptosis. FR901228, FK228, or depsipeptide, is an HDAC inhibitor effective in T-cell lymphomas. Adult T-cell leukemia (ATL) is caused by human T-cell leukemia virus type 1 (HTLV-1) and remains incurable. We examined whether FR901228 is effective for treatment of ATL by assessing its ability to induce apoptosis of HTLV-1-infected T-cell lines and primary leukemic cells from ATL patients. FR901228 induced apoptosis of Tax-expressing and -unexpressing HTLV-1-infected T-cell lines and selective apoptosis of primary ATL cells, especially those of patients with acute ATL. FR901228 also efficiently reduced the DNA binding of NF-kappaB and AP-1 in HTLV-1-infected T-cell lines and primary ATL cells and down-regulated the expression of Bcl-x(L) and cyclin D2, regulated by NF-kappaB. Although the viral protein Tax is an activator of NF-kappaB and AP-1, FR901228-induced apoptosis was not associated with reduced expression of Tax. In vivo use of FR901228 partly inhibited the growth of tumors of HTLV-1-infected T cells transplanted subcutaneously in SCID mice. Our results indicated that FR901228 could induce apoptosis of these cells and suppress the expression of NF-kappaB and AP-1 and suggest that FR901228 could be therapeutically effective in ATL.
Collapse
Affiliation(s)
- Naoki Mori
- Division of Molecular Virology and Oncology, Faculty of Medicine, University of the Ryukyus, Nishihara, Okinawa 903-0215, Japan.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
|
31
|
Hirata A, Higuchi M, Niinuma A, Ohashi M, Fukushi M, Oie M, Akiyama T, Tanaka Y, Gejyo F, Fujii M. PDZ domain-binding motif of human T-cell leukemia virus type 1 Tax oncoprotein augments the transforming activity in a rat fibroblast cell line. Virology 2004; 318:327-36. [PMID: 14972558 DOI: 10.1016/j.virol.2003.10.006] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2003] [Revised: 10/09/2003] [Accepted: 10/13/2003] [Indexed: 11/17/2022]
Abstract
While human T-cell leukemia virus type 1 (HTLV-1) is associated with the development of adult T-cell leukemia (ATL), HTLV-2 has not been reported to be associated with such malignant leukemias. HTLV-1 Tax1 oncoprotein transforms a rat fibroblast cell line (Rat-1) to form multiple large colonies in soft agar, and this activity is much greater than that of HTLV-2 Tax2. We have demonstrated here that the increased number of transformed colonies induced by Tax1 relative to Tax2 was mediated by a PDZ domain-binding motif (PBM) in Tax1, which is absent in Tax2. Tax1 PBM mediated the interaction of Tax1 with the discs large (Dlg) tumor suppressor containing PDZ domains, and the interaction correlated well with the transforming activities of Tax1 and the mutants. Through this interaction, Tax1 altered the subcellular localization of Dlg from the detergent-soluble to the detergent-insoluble fraction in a fibroblast cell line as well as in HTLV-1-infected T-cell lines. These results suggest that the interaction of Tax1 with PDZ domain protein(s) is critically involved in the transforming activity of Tax1, the activity of which may be a crucial factor in malignant transformation of HTLV-1-infected cells in vivo.
Collapse
Affiliation(s)
- Akira Hirata
- Division of Virology, Niigata University Graduate School of Medical and Dental Sciences, Niigata 951-8510, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Ohashi M, Sakurai M, Higuchi M, Mori N, Fukushi M, Oie M, Coffey RJ, Yoshiura K, Tanaka Y, Uchiyama M, Hatanaka M, Fujii M. Human T-cell leukemia virus type 1 Tax oncoprotein induces and interacts with a multi-PDZ domain protein, MAGI-3. Virology 2004; 320:52-62. [PMID: 15003862 DOI: 10.1016/j.virol.2003.11.014] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2003] [Revised: 10/29/2003] [Accepted: 11/12/2003] [Indexed: 11/23/2022]
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) is the causative agent of adult T-cell leukemia (ATL), whereas the closely related virus HTLV-2 has not been associated with such malignant conditions. HTLV-1 Tax1 oncoprotein transforms a rat fibroblast cell line (Rat-1) much more efficiently than does HTLV-2 Tax2. By using a differential display analysis, we isolated MAGI-3 as a Tax1-inducible gene in Rat-1 cells. Reverse transcription-polymerase chain reaction (RT-PCR) analysis confirmed that Tax1 induced MAGI-3 in Rat-1 cells. MAGI-3 has multiple PDZ domains and interacted with Tax1 but not Tax2 in 293T cells. The interaction of Tax1 with MAGI-3 was dependent on a PDZ domain-binding motif, which is missing in Tax2. The interaction of Tax1 with MAGI-3 altered their respective subcellular localization, and moreover, the interaction correlated well with the high transforming activities of Tax1 in Rat-1 cells relative to Tax2. MAGI-3 mRNA and the allied MAGI-1, but not MAGI-2, were expressed in HTLV-1-infected T-cell lines. Our results suggest that the interaction of Tax1 and MAGI-3 alters their respective biological activities, which may play a role in transformation by Tax1 as well as in the pathogenesis of HTLV-1-associated diseases.
Collapse
Affiliation(s)
- Minako Ohashi
- Division of Virology, Niigata University Graduate School of Medical and Dental Sciences, Niigata 951-8510, Japan
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Franchini G, Fukumoto R, Fullen JR. T-Cell Control by Human T-Cell Leukemia/Lymphoma Virus Type 1. Int J Hematol 2003; 78:280-96. [PMID: 14686485 DOI: 10.1007/bf02983552] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Human T-cell leukemia/lymphoma virus type 1 (HTLV-1) causes neoplastic transformation of human T-cells in a small number of infected individuals several years from infection. Collective evidence from in vitro studies indicates that several viral proteins act in concert to increase the responsiveness of T-cells to extracellular stimulation, modulate proapoptotic and antiapoptotic gene signals, enhance T-cell survival, and avoid immune recognition of the infected T-cells. The virus promotes T-cell proliferation by usurping several signaling pathways central to immune T-cell function, such as antigen stimulation and receptor-ligand interaction, suggesting that extracellular signals are important for HTLV-1 oncogenesis. Environmental factors such as chronic antigen stimulation may therefore be of importance, as also suggested by epidemiological data. Thus genetic and environmental factors together with the virus contribute to disease development. This review focuses on current knowledge of the mechanisms regulating HTLV-1 replication and the T-cell pathways that are usurped by viral proteins to induce and maintain clonal proliferation of infected T-cells. The relevance of these laboratory findings is related to clonal T-cell proliferation and adult T-cell leukemia/lymphoma development in vivo.
Collapse
Affiliation(s)
- Genoveffa Franchini
- Basic Research Laboratory, National Cancer Institute, Bethesda, Maryland 20892-5055, USA.
| | | | | |
Collapse
|
34
|
Gatza ML, Watt JC, Marriott SJ. Cellular transformation by the HTLV-I Tax protein, a jack-of-all-trades. Oncogene 2003; 22:5141-9. [PMID: 12910251 DOI: 10.1038/sj.onc.1206549] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The human T-cell leukemia virus type I (HTLV-I) is an oncogenic retrovirus that is responsible for adult T-cell leukemia and a neurological disease, HTLV-I-associated myelopathy/tropical spastic paraparesis. HTLV-I encodes an oncogenic protein, Tax, which affects a variety of cellular functions prompting it to be referred to as a jack-of-all trades. The ability of Tax to both transcriptionally regulate cellular gene expression and to functionally inactivate proteins involved in cell-cycle progression and DNA repair provide the basis for Tax-mediated transformation and leukemogenesis. This review will concentrate on the effects of Tax on the dysregulation of the G(1)/S and G(2)/M checkpoints as well as the suppression of DNA damage repair leading to cellular transformation.
Collapse
Affiliation(s)
- Michael L Gatza
- Interdepartmental Program in Cell and Molecular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | | | | |
Collapse
|
35
|
Tato CM, Villarino A, Caamaño JH, Boothby M, Hunter CA. Inhibition of NF-kappa B activity in T and NK cells results in defective effector cell expansion and production of IFN-gamma required for resistance to Toxoplasma gondii. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:3139-46. [PMID: 12626571 DOI: 10.4049/jimmunol.170.6.3139] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
To define the role of NF-kappa B in the development of T cell responses required for resistance to Toxoplasma gondii, mice in which T cells are transgenic for a degradation-resistant (Delta N) form of I kappa B alpha, an inhibitor of NF-kappa B, were challenged with T. gondii and their response to infection compared with control mice. I kappa B alpha(Delta N)-transgenic (Tg) mice succumbed to T. gondii infection between days 12 and 35, and death was associated with an increased parasite burden compared with wild-type (Wt) controls. Analysis of the responses of infected mice revealed that IL-12 responses were comparable between strains, but Tg mice had a marked reduction in systemic levels of IFN-gamma, the major mediator of resistance to T. gondii. In addition, the infection-induced increase in NK cell activity observed in Wt mice was absent from Tg mice and this correlated with NK cell expression of the transgene. Infection-induced activation of CD4(+) T cells was similar in Wt and Tg mice, but expansion of activated CD4(+)T cells was markedly reduced in the Tg mice. This difference in T cell numbers correlated with a reduced capacity of these cells to proliferate after stimulation and was associated with a major defect in the ability of CD4(+) T cells from infected mice to produce IFN-gamma. Together, these studies reveal that inhibition of NF-kappa B activity in T and NK cells results in defective effector cell expansion and production of IFN-gamma required for resistance to T. gondii.
Collapse
MESH Headings
- Animals
- Antigens, Protozoan/pharmacology
- CD4-Positive T-Lymphocytes/immunology
- CD4-Positive T-Lymphocytes/metabolism
- CD4-Positive T-Lymphocytes/pathology
- Cell Division/genetics
- Cell Division/immunology
- Cytotoxicity, Immunologic/genetics
- Female
- Genetic Predisposition to Disease
- I-kappa B Proteins/genetics
- Immunity, Innate/genetics
- Interferon-gamma/biosynthesis
- Interferon-gamma/physiology
- Killer Cells, Natural/immunology
- Killer Cells, Natural/metabolism
- Killer Cells, Natural/pathology
- Lymphocyte Activation/genetics
- Lymphocyte Activation/immunology
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Inbred CBA
- Mice, Transgenic
- NF-KappaB Inhibitor alpha
- NF-kappa B/antagonists & inhibitors
- NF-kappa B/metabolism
- Toxoplasma/immunology
- Toxoplasmosis, Animal/genetics
- Toxoplasmosis, Animal/immunology
- Toxoplasmosis, Animal/pathology
- Transgenes/immunology
Collapse
Affiliation(s)
- Cristina M Tato
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | | | | | | |
Collapse
|
36
|
Franchini G, Nicot C, Johnson JM. Seizing of T Cells by Human T-Cell Leukemia⧸Lymphoma Virus Type 1. Adv Cancer Res 2003; 89:69-132. [PMID: 14587871 DOI: 10.1016/s0065-230x(03)01003-0] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Human T-cell leukemia/lymphoma virus type 1 (HTLV-1) causes neoplastic transformation of human T-cells in a small number of infected individuals several years from infection. Several viral proteins act in concert to increase the responsiveness of T-cells to extracellular stimulation, modulate proapoptotic and antiapoptotic gene signals, enhance T-cell survival, and avoid immune recognition of the infected T-cells. The virus promotes T-cell proliferation by usurping several signaling pathways central to immune T-cell function. Viral proteins modulate the downstream effects of antigen stimulation and receptor-ligand interaction, suggesting that extracellular signals are important for HTLV-1 oncogenesis. Environmental factors such as chronic antigen stimulation are therefore important, as also suggested by epidemiological data. The ability of a given individual to respond to specific antigens is determined genetically. Thus, genetic and environmental factors, together with the virus, contribute to disease development. As in the case of other virus-associated cancers, HTLV-1-induced leukemia/lymphoma can be prevented by avoiding viral infection or by intervention during the asymptomatic phase with approaches able to interrupt the vicious cycle of virus-induced proliferation of a subset of T-cells. This review focuses on current knowledge of the mechanisms regulating HTLV-1 replication and the T-cell pathways that are usurped by viral proteins to induce and maintain clonal proliferation of infected T-cells in vitro. The relevance of these laboratory findings will be related to clonal T-cell proliferation and adult T-cell leukemia/lymphoma development in vivo.
Collapse
Affiliation(s)
- Genoveffa Franchini
- National Cancer Institute, Basic Research Laboratory, Bethesda, Maryland 20892, USA
| | | | | |
Collapse
|