1
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Huber PB, Rao A, LaBonne C. BET activity plays an essential role in control of stem cell attributes in Xenopus. Development 2024; 151:dev202990. [PMID: 38884356 PMCID: PMC11266789 DOI: 10.1242/dev.202990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Accepted: 05/31/2024] [Indexed: 06/18/2024]
Abstract
Neural crest cells are a stem cell population unique to vertebrate embryos that retains broad multi-germ layer developmental potential through neurulation. Much remains to be learned about the genetic and epigenetic mechanisms that control the potency of neural crest cells. Here, we examine the role that epigenetic readers of the BET (bromodomain and extra terminal) family play in controlling the potential of pluripotent blastula and neural crest cells. We find that inhibiting BET activity leads to loss of pluripotency at blastula stages and a loss of neural crest at neurula stages. We compare the effects of HDAC (an eraser of acetylation marks) and BET (a reader of acetylation) inhibition and find that they lead to similar cellular outcomes through distinct effects on the transcriptome. Interestingly, loss of BET activity in cells undergoing lineage restriction is coupled to increased expression of genes linked to pluripotency and prolongs the competence of initially pluripotent cells to transit to a neural progenitor state. Together these findings advance our understanding of the epigenetic control of pluripotency and the formation of the vertebrate neural crest.
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Affiliation(s)
- Paul B. Huber
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
- National Institute for Theory and Mathematics in Biology, Northwestern University, Evanston, IL 60208, USA
| | - Anjali Rao
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Carole LaBonne
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
- National Institute for Theory and Mathematics in Biology, Northwestern University, Evanston, IL 60208, USA
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2
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Palumbo GA, Duminuco A. Myelofibrosis: In Search for BETter Targeted Therapies. J Clin Oncol 2023; 41:5044-5048. [PMID: 37751563 DOI: 10.1200/jco.23.00833] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 07/22/2023] [Accepted: 07/31/2023] [Indexed: 09/28/2023] Open
Affiliation(s)
- Giuseppe A Palumbo
- Department of Scienze Mediche, Chirurgiche e Tecnologie Avanzate "G.F. Ingrassia," University of Catania, Catania, Italy
| | - Andrea Duminuco
- Postgraduate School of Hematology, University of Catania, Catania, Italy
- Department of Haematology, Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom
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3
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Rao A, Ni Z, Suresh D, Mohanty C, Wang AR, Lee DL, Nickel KP, Varambally SRJ, Lambert PF, Kendziorski C, Iyer G. Targeted inhibition of BET proteins in HPV-16 associated head and neck squamous cell carcinoma reveals heterogeneous transcription response. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.02.560587. [PMID: 37873389 PMCID: PMC10592929 DOI: 10.1101/2023.10.02.560587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Integrated human papillomavirus (HPV-16) associated head and neck squamous cell carcinoma (HNSCC) tumors have worse survival outcomes compared to episomal HPV-16 HNSCC tumors. Therefore, there is a need to differentiate treatment for HPV-16 integrated HNSCC from other viral forms. We analyzed TCGA data and found that HPV+ HNSCC expressed higher transcript levels of the bromodomain and extra terminal domain (BET) family of transcriptional coregulators. However, the mechanism of BET protein-mediated transcription of viral-cellular genes in the integrated viral-HNSCC genomes needs to be better understood. We show that BET inhibition downregulates E6 significantly independent of the viral transcription factor, E2, and there was overall heterogeneity in the downregulation of viral transcription in response to the effects of BET inhibition across HPV-associated cell lines. Chemical BET inhibition was phenocopied with the knockdown of BRD4 and mirrored downregulation of viral E6 and E7 expression. Strikingly, there was heterogeneity in the reactivation of p53 levels despite E6 downregulation, while E7 downregulation did not alter Rb levels significantly. We identified that BET inhibition directly downregulated c-Myc and E2F expression and induced CDKN1A expression. Overall, our studies show that BET inhibition provokes a G1-cell cycle arrest with apoptotic activity and suggests that BET inhibition regulates both viral and cellular gene expression in HPV-associated HNSCC.
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Affiliation(s)
- Aakarsha Rao
- Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, University of Wisconsin, Madison, WI, 53705, USA
| | - Zijian Ni
- Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Dhruthi Suresh
- Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, University of Wisconsin, Madison, WI, 53705, USA
| | - Chitrasen Mohanty
- Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Albert R. Wang
- Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, University of Wisconsin, Madison, WI, 53705, USA
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Denis L Lee
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
- University of Wisconsin Carbone Cancer Center, Madison, 53705, WI, USA
| | - Kwangok P. Nickel
- Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, University of Wisconsin, Madison, WI, 53705, USA
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - Sooryanarayana Randall J. Varambally
- Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, University of Wisconsin, Madison, WI, 53705, USA
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
- Molecular and Cellular Pathology, Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, 35233, USA
| | - Paul F. Lambert
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
- University of Wisconsin Carbone Cancer Center, Madison, 53705, WI, USA
| | - Christina Kendziorski
- Department of Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Gopal Iyer
- Department of Human Oncology, University of Wisconsin School of Medicine and Public Health, University of Wisconsin, Madison, WI, 53705, USA
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
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4
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Dong J, Wang X. Identification of novel BRD4 inhibitors by pharmacophore screening, molecular docking, and molecular dynamics simulation. J Mol Struct 2023. [DOI: 10.1016/j.molstruc.2022.134363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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5
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Wang C, Xu Q, Zhang X, Day DS, Abraham BJ, Lun K, Chen L, Huang J, Ji X. BRD2 interconnects with BRD3 to facilitate Pol II transcription initiation and elongation to prime promoters for cell differentiation. Cell Mol Life Sci 2022; 79:338. [PMID: 35665862 PMCID: PMC11072765 DOI: 10.1007/s00018-022-04349-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 04/20/2022] [Accepted: 05/04/2022] [Indexed: 11/03/2022]
Abstract
The bromodomain and extraterminal motif (BET) proteins are critical drug targets for diseases. The precise functions and relationship of BRD2 with other BET proteins remain elusive mechanistically. Here, we used acute protein degradation and quantitative genomic and proteomic approaches to investigate the primary functions of BRD2 in transcription. We report that BRD2 is required for TAF3-mediated Pol II initiation at promoters with low levels of H3K4me3 and for R-loop suppression during Pol II elongation. Single and double depletion revealed that BRD2 and BRD3 function additively, independently, or perhaps antagonistically in Pol II transcription at different promoters. Furthermore, we found that BRD2 regulates the expression of different genes during embryonic body differentiation processes by promoter priming in embryonic stem cells. Therefore, our results suggest complex interconnections between BRD2 and BRD3 at promoters to fine-tune Pol II initiation and elongation for control of cell state.
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Affiliation(s)
- Chenlu Wang
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Qiqin Xu
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Xianhong Zhang
- Hubei Key Laboratory of Cell Homeostasis, RNA Institute, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Daniel S Day
- Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA, 02142, USA
| | - Brian J Abraham
- Whitehead Institute for Biomedical Research, 9 Cambridge Center, Cambridge, MA, 02142, USA
- Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Kehuan Lun
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Liang Chen
- Hubei Key Laboratory of Cell Homeostasis, RNA Institute, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Jie Huang
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China.
| | - Xiong Ji
- Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education, School of Life Sciences, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China.
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6
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Progress in the development of domain selective inhibitors of the bromo and extra terminal domain family (BET) proteins. Eur J Med Chem 2021; 226:113853. [PMID: 34547507 DOI: 10.1016/j.ejmech.2021.113853] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 09/04/2021] [Accepted: 09/11/2021] [Indexed: 12/13/2022]
Abstract
Dysfunction of the bromo and extra terminal domain (BET) family proteins is associated with many human diseases, therefore the BET family proteins have been considered as promising targets for drug development. Numerous small molecular compounds targeting the N-terminal two tandem bromodomains BD1 and BD2 of the BET family proteins have been reported, and a number of them have been advanced into clinical trials. Most of the BET inhibitors entered clinical trials are pan-BET inhibitors which show poor selectivity among BET members and bind to the BD1 and BD2 of the BET family proteins with comparable binding affinities. In order to elucidate the distinct functions of BD1s and BD2s, many BD1 and BD2 selective BET inhibitors have also been developed. In this review, we summarized the recent progress in the development of BD1 and BD2 selective BET inhibitors, and provided the perspectives for future studies of BET inhibitors.
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7
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Zhou L, Han YF, Yuan C, Duan ZQ. Screening and bioinformatics analysis of cellular proteins interacting with chicken bromodomain-containing protein 2 in DF-1 cells. Br Poult Sci 2021; 62:810-819. [PMID: 34152239 DOI: 10.1080/00071668.2021.1943311] [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] [Indexed: 10/21/2022]
Abstract
1. Bromodomain-containing protein 2 (BRD2) is an important member of the BET protein family, which can specifically bind histone acetylated lysine to participate in gene transcriptional regulation, chromatin remodelling, cell proliferation and apoptosis. The following investigation of cellular proteins interacting with chBRD2 will be helpful in understanding the new functions of chBRD2 and the mechanism of NDV replication.2. The recombinant eukaryotic expression vector pEGFP-chBRD2 and empty vector pEGFP-C1 were transfected into DF-1 cells to overexpress GFP-chBRD2 and GFP, respectively. GO annotation, KEGG pathway, and protein-protein interaction network were used to analyse the cellular proteins interacting with chBRD2. In addition, one targeted protein was selected to verify its interaction with chBRD2 using fluorescent co-localisation and Co-IP.3. A total of 225 cellular proteins were identified that potentially interact with chBRD2. GO analysis showed that these play key roles in gene transcriptional regulation, cell cycle and development, immunity and viral infection. Further KEGG pathway analysis showed that these proteins were mainly involved in genetic information processing, immune system, cellular processes and translation. In addition, one targeted cellular protein chicken matrin 3 (chMATR3) was also identified as chBRD2 complex using both fluorescence co-localisation and Co-IP analysis.4. This study presents the interactome data of chBRD2 protein in DF-1 cells, which provides new information to understand the functions of chBRD2 and new targets for further investigating the replication and pathogenesis of NDV.
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Affiliation(s)
- L Zhou
- Key Laboratory of Animal Genetics, Breeding and Reproduction in the Plateau Mountains Region, Ministry of Education (Guizhou University)/Key Laboratory of Animal Genetics, Breeding and Reproduction in Guizhou Province, Guiyang, China.,College of Animal Sciences, Guizhou University, Guiyang, China
| | - Y F Han
- Key Laboratory of Animal Genetics, Breeding and Reproduction in the Plateau Mountains Region, Ministry of Education (Guizhou University)/Key Laboratory of Animal Genetics, Breeding and Reproduction in Guizhou Province, Guiyang, China.,College of Animal Sciences, Guizhou University, Guiyang, China
| | - C Yuan
- Key Laboratory of Animal Genetics, Breeding and Reproduction in the Plateau Mountains Region, Ministry of Education (Guizhou University)/Key Laboratory of Animal Genetics, Breeding and Reproduction in Guizhou Province, Guiyang, China.,College of Animal Sciences, Guizhou University, Guiyang, China
| | - Z Q Duan
- Key Laboratory of Animal Genetics, Breeding and Reproduction in the Plateau Mountains Region, Ministry of Education (Guizhou University)/Key Laboratory of Animal Genetics, Breeding and Reproduction in Guizhou Province, Guiyang, China.,College of Animal Sciences, Guizhou University, Guiyang, China
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8
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Chavez DR, Lee PC, Comizzoli P. Oocyte Meiotic Competence in the Domestic Cat Model: Novel Roles for Nuclear Proteins BRD2 and NPM1. Front Cell Dev Biol 2021; 9:670021. [PMID: 34012967 PMCID: PMC8126674 DOI: 10.3389/fcell.2021.670021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 04/12/2021] [Indexed: 12/03/2022] Open
Abstract
To participate in fertilization and embryo development, oocytes stored within the mammalian female ovary must resume meiosis as they are arrested in meiotic prophase I. This ability to resume meiosis, known as meiotic competence, requires the tight regulation of cellular metabolism and chromatin configuration. Previously, we identified nuclear proteins associated with the transition from the pre-antral to the antral follicular stage, the time at which oocytes gain meiotic competence. In this study, the objective was to specifically investigate three candidate nuclear factors: bromodomain containing protein 2 (BRD2), nucleophosmin 1 (NPM1), and asparaginase-like 1 (ASRGL1). Although these three factors have been implicated with folliculogenesis or reproductive pathologies, their requirement during oocyte maturation is unproven in any system. Experiments were conducted using different stages of oocytes isolated from adult cat ovaries. The presence of candidate factors in developing oocytes was confirmed by immunostaining. While BRD2 and ASRGL1 protein increased between pre-antral and the antral stages, changes in NPM1 protein levels between stages were not observed. Using protein inhibition experiments, we found that most BRD2 or NPM1-inhibited oocytes were incapable of participating in fertilization or embryo development. Further exploration revealed that inhibition of BRD2 and NPM-1 in cumulus-oocyte-complexes prevented oocytes from maturing to the metaphase II stage. Rather, they remained at the germinal vesicle stage or arrested shortly after meiotic resumption. We therefore have identified novel factors playing critical roles in domestic cat oocyte meiotic competence. The identification of these factors will contribute to improvement of domestic cat assisted reproduction and could serve as biomarkers of meiotically competent oocytes in other species.
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Affiliation(s)
- Daniela R Chavez
- Smithsonian Conservation Biology Institute, National Zoological Park, Washington, DC, United States
| | - Pei-Chih Lee
- Smithsonian Conservation Biology Institute, National Zoological Park, Washington, DC, United States
| | - Pierre Comizzoli
- Smithsonian Conservation Biology Institute, National Zoological Park, Washington, DC, United States
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9
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Shorstova T, Foulkes WD, Witcher M. Achieving clinical success with BET inhibitors as anti-cancer agents. Br J Cancer 2021; 124:1478-1490. [PMID: 33723398 PMCID: PMC8076232 DOI: 10.1038/s41416-021-01321-0] [Citation(s) in RCA: 191] [Impact Index Per Article: 63.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 01/12/2021] [Accepted: 02/11/2021] [Indexed: 12/16/2022] Open
Abstract
The transcriptional upregulation of oncogenes is a driving force behind the progression of many tumours. However, until a decade ago, the concept of 'switching off' these oncogenic pathways represented a formidable challenge. Research has revealed that members of the bromo- and extra-terminal domain (BET) motif family are key activators of oncogenic networks in a spectrum of cancers; their function depends on their recruitment to chromatin through two bromodomains (BD1 and BD2). The advent of potent inhibitors of BET proteins (BETi), which target either one or both bromodomains, represents an important step towards the goal of suppressing oncogenic networks within tumours. Here, we discuss the biology of BET proteins, advances in BETi design and highlight potential biomarkers predicting their activity. We also outline the logic of incorporating BETi into combination therapies to enhance its efficacy. We suggest that understanding mechanisms of activity, defining predictive biomarkers and identifying potent synergies represents a roadmap for clinical success using BETi.
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Affiliation(s)
- Tatiana Shorstova
- grid.414980.00000 0000 9401 2774Departments of Oncology and Experimental Medicine, McGill University, Lady Davis Institute and Segal Cancer Centre, Jewish General Hospital, Montreal, QC Canada
| | - William D. Foulkes
- grid.414980.00000 0000 9401 2774Departments of Oncology and Human Genetics, McGill University, Lady Davis Institute and Segal Cancer Centre, Jewish General Hospital, Montreal, QC Canada
| | - Michael Witcher
- grid.414980.00000 0000 9401 2774Departments of Oncology and Experimental Medicine, McGill University, Lady Davis Institute and Segal Cancer Centre, Jewish General Hospital, Montreal, QC Canada
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10
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Cribbs AP, Filippakopoulos P, Philpott M, Wells G, Penn H, Oerum H, Valge-Archer V, Feldmann M, Oppermann U. Dissecting the Role of BET Bromodomain Proteins BRD2 and BRD4 in Human NK Cell Function. Front Immunol 2021; 12:626255. [PMID: 33717143 PMCID: PMC7953504 DOI: 10.3389/fimmu.2021.626255] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 01/13/2021] [Indexed: 12/19/2022] Open
Abstract
Natural killer (NK) cells are innate lymphocytes that play a pivotal role in the immune surveillance and elimination of transformed or virally infected cells. Using a chemo-genetic approach, we identify BET bromodomain containing proteins BRD2 and BRD4 as central regulators of NK cell functions, including direct cytokine secretion, NK cell contact-dependent inflammatory cytokine secretion from monocytes as well as NK cell cytolytic functions. We show that both BRD2 and BRD4 control inflammatory cytokine production in NK cells isolated from healthy volunteers and from rheumatoid arthritis patients. In contrast, knockdown of BRD4 but not of BRD2 impairs NK cell cytolytic responses, suggesting BRD4 as critical regulator of NK cell mediated tumor cell elimination. This is supported by pharmacological targeting where the first-generation pan-BET bromodomain inhibitor JQ1(+) displays anti-inflammatory effects and inhibit tumor cell eradication, while the novel bivalent BET bromodomain inhibitor AZD5153, which shows differential activity towards BET family members, does not. Given the important role of both cytokine-mediated inflammatory microenvironment and cytolytic NK cell activities in immune-oncology therapies, our findings present a compelling argument for further clinical investigation.
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Affiliation(s)
- Adam P Cribbs
- Botnar Research Center, Nuffield Department of Orthopedics, Rheumatology and Musculoskeletal Sciences, National Institute of Health Research Oxford Biomedical Research Unit (BRU), University of Oxford, Oxford, United Kingdom
| | | | - Martin Philpott
- Botnar Research Center, Nuffield Department of Orthopedics, Rheumatology and Musculoskeletal Sciences, National Institute of Health Research Oxford Biomedical Research Unit (BRU), University of Oxford, Oxford, United Kingdom
| | - Graham Wells
- Botnar Research Center, Nuffield Department of Orthopedics, Rheumatology and Musculoskeletal Sciences, National Institute of Health Research Oxford Biomedical Research Unit (BRU), University of Oxford, Oxford, United Kingdom
| | - Henry Penn
- Arthritis Centre, Northwick Park Hospital, Harrow, United Kingdom
| | - Henrik Oerum
- Roche Innovation Center Copenhagen A/S, Hørsholm, Denmark
| | - Viia Valge-Archer
- Bioscience, Research and Early Development, Oncology R&D, AstraZeneca, Cambridge, United Kingdom
| | - Marc Feldmann
- Kennedy Institute of Rheumatology Nuffield Department of Orthopedics, Rheumatology and Musculoskeletal Sciences, Botnar Research Centre, Oxford, United Kingdom
| | - Udo Oppermann
- Botnar Research Center, Nuffield Department of Orthopedics, Rheumatology and Musculoskeletal Sciences, National Institute of Health Research Oxford Biomedical Research Unit (BRU), University of Oxford, Oxford, United Kingdom.,Freiburg Institute of Advanced Studies, Freiburg, Germany.,Oxford Centre for Translational Myeloma Research, Oxford, United Kingdom
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11
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Sun Y, Han J, Wang Z, Li X, Sun Y, Hu Z. Safety and Efficacy of Bromodomain and Extra-Terminal Inhibitors for the Treatment of Hematological Malignancies and Solid Tumors: A Systematic Study of Clinical Trials. Front Pharmacol 2021; 11:621093. [PMID: 33574760 PMCID: PMC7870522 DOI: 10.3389/fphar.2020.621093] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Accepted: 12/23/2020] [Indexed: 12/31/2022] Open
Abstract
Background: The upregulated expression of BET proteins is closely associated with the occurrence and development of hematological malignancies and solid tumors. Several BET inhibitors have been developed, and some have been in phase I/II of clinical trials. Here, the safety, efficacy, and pharmacodynamics of ten BET inhibitors currently in clinical trials were evaluated. Methods: We retrieved and reviewed published reports on the clinical trials of twelve BET inhibitors including AZD5153, ABBV-075, BMS-986158, CPI-0610, GSK525762, OTX-015, PLX51107, INCB054329, INCB057643, FT-1101, CC-90010, and ODM-207 for patients with hematological malignancies and solid tumors and summarized their published target genes. Results: In the monotherapy of BET inhibitors, the most common and severe (grade ≥3) hematological adverse events (AEs) are thrombocytopenia, anemia, and neutropenia. The most common non-hematological syndromes are diarrhea, nausea, fatigue, dysgeusia, and decreased appetite, while the most severe AE is pneumonia. Additionally, Tmax of these BET inhibitors was between 0.5–6 h, but the range for T1/2 varied significantly. According to published data, the rates of SD, PD, CR and PR were 27.4%, 37.6%, 3.5%, and 5.7%, respectively, which is not very satisfactory. In addition to BRD4, oncogene MYC is another common target gene of these BET inhibitors. Ninety-seven signaling pathways may be regulated by BET inhibitors. Conclusion: All BET inhibitors reviewed in our study exhibited exposure-dependent thrombocytopenia, which may limit their clinical application. Moreover, further efforts are necessary to explore the optimal dosing schemes and combinations to maximize the efficacy of BET inhibitors.
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Affiliation(s)
- Yanli Sun
- Laboratory for Stem Cell and Regenerative Medicine, Affiliated Hospital of Weifang Medical University, Weifang, China.,Department of Laboratory Medicine, Weifang Medical University, Weifang, China
| | - Jie Han
- Weifang Medical University, Weifang, China
| | - Zhanzhao Wang
- Department of Laboratory Medicine, Weifang People's Hospital, Weifang, China
| | - Xuening Li
- Weifang Medical University, Weifang, China
| | - Yanhua Sun
- Department of Hematology, Weifang People's Hospital, Weifang, China
| | - Zhenbo Hu
- Laboratory for Stem Cell and Regenerative Medicine, Affiliated Hospital of Weifang Medical University, Weifang, China.,Department of Hematology, Affiliated Hospital of Weifang Medical University, Weifang, China
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12
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Her YR, Wang L, Chepelev I, Manterola M, Berkovits B, Cui K, Zhao K, Wolgemuth DJ. Genome-wide chromatin occupancy of BRDT and gene expression analysis suggest transcriptional partners and specific epigenetic landscapes that regulate gene expression during spermatogenesis. Mol Reprod Dev 2021; 88:141-157. [PMID: 33469999 DOI: 10.1002/mrd.23449] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 12/13/2020] [Accepted: 12/27/2020] [Indexed: 11/09/2022]
Abstract
BRDT, a member of the BET family of double bromodomain-containing proteins, is essential for spermatogenesis in the mouse and has been postulated to be a key regulator of transcription in meiotic and post-meiotic cells. To understand the function of BRDT in these processes, we first characterized the genome-wide distribution of the BRDT binding sites, in particular within gene units, by ChIP-Seq analysis of enriched fractions of pachytene spermatocytes and round spermatids. In both cell types, BRDT binding sites were mainly located in promoters, first exons, and introns of genes. BRDT binding sites in promoters overlapped with several histone modifications and histone variants associated with active transcription, and were enriched for consensus sequences for specific transcription factors, including MYB, RFX, ETS, and ELF1 in pachytene spermatocytes, and JunD, c-Jun, CRE, and RFX in round spermatids. Subsequent integration of the ChIP-seq data with available transcriptome data revealed that stage-specific gene expression programs are associated with BRDT binding to their gene promoters, with most of the BDRT-bound genes being upregulated. Gene Ontology analysis further identified unique sets of genes enriched in diverse biological processes essential for meiosis and spermiogenesis between the two cell types, suggesting distinct developmentally stage-specific functions for BRDT. Taken together, our data suggest that BRDT cooperates with different transcription factors at distinctive chromatin regions within gene units to regulate diverse downstream target genes that function in male meiosis and spermiogenesis.
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Affiliation(s)
- Yoon Ra Her
- Department of Genetics & Development, Columbia University Medical Center, New York, New York, USA
| | - Li Wang
- Department of Genetics & Development, Columbia University Medical Center, New York, New York, USA
| | - Iouri Chepelev
- Systems Biology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA.,Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.,Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Marcia Manterola
- Human Genetics Program, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Santiago, Chile
| | - Binyamin Berkovits
- Department of Genetics & Development, Columbia University Medical Center, New York, New York, USA
| | - Kairong Cui
- Systems Biology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Keji Zhao
- Systems Biology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Debra J Wolgemuth
- Department of Genetics & Development, Columbia University Medical Center, New York, New York, USA.,Department Obstetrics & Gynecology, Columbia University Medical Center, New York, New York, USA.,Institute of Human Nutrition, Columbia University Medical Center, New York, New York, USA.,Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, New York, USA
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13
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Czapski GA, Zhao Y, Lukiw WJ, Strosznajder JB. Acute Systemic Inflammatory Response Alters Transcription Profile of Genes Related to Immune Response and Ca 2+ Homeostasis in Hippocampus; Relevance to Neurodegenerative Disorders. Int J Mol Sci 2020; 21:ijms21217838. [PMID: 33105802 PMCID: PMC7660108 DOI: 10.3390/ijms21217838] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 10/13/2020] [Accepted: 10/19/2020] [Indexed: 12/22/2022] Open
Abstract
Acute systemic inflammatory response (SIR) triggers an alteration in the transcription of brain genes related to neuroinflammation, oxidative stress and cells death. These changes are also characteristic for Alzheimer’s disease (AD) neuropathology. Our aim was to evaluate gene expression patterns in the mouse hippocampus (MH) by using microarray technology 12 and 96 h after SIR evoked by lipopolysaccharide (LPS). The results were compared with microarray analysis of human postmortem hippocampal AD tissues. It was found that 12 h after LPS administration the expression of 231 genes in MH was significantly altered (FC > 2.0); however, after 96 h only the S100a8 gene encoding calgranulin A was activated (FC = 2.9). Gene ontology enrichment analysis demonstrated the alteration of gene expression related mostly to the immune-response including the gene Lcn2 for Lipocalin 2 (FC = 237.8), involved in glia neurotoxicity. The expression of genes coding proteins involved in epigenetic regulation, histone deacetylases (Hdac4,5,8,9,11) and bromo- and extraterminal domain protein Brd3 were downregulated; however, Brd2 was found to be upregulated. Remarkably, the significant increase in expression of Lcn2, S100a8, S100a9 and also Saa3 and Ch25h, was found in AD brains suggesting that early changes of immune-response genes evoked by mild SIR could be crucial in AD pathogenesis.
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Affiliation(s)
- Grzegorz A. Czapski
- Department of Cellular Signalling, Mossakowski Medical Research Centre Polish Academy of Sciences, Pawińskiego 5, 02-106 Warsaw, Poland
- Correspondence: (G.A.C.); (J.B.S.); Tel.: +48-22-6086-600 (G.A.C.); +48-22-6086-414 (J.B.S.)
| | - Yuhai Zhao
- LSU Neuroscience Center, Louisiana State University Health Science Center (LSU-HSC), New Orleans, LA 70112, USA; (Y.Z.); (W.J.L.)
- Department of Cell Biology and Anatomy, LSU-HSC, New Orleans, LA 70112, USA
| | - Walter J. Lukiw
- LSU Neuroscience Center, Louisiana State University Health Science Center (LSU-HSC), New Orleans, LA 70112, USA; (Y.Z.); (W.J.L.)
- Department of Ophthalmology, LSU-HSC, New Orleans, LA 70112, USA
- Department of Neurology, LSU-HSC, New Orleans, LA 70112, USA
| | - Joanna B. Strosznajder
- Department of Cellular Signalling, Mossakowski Medical Research Centre Polish Academy of Sciences, Pawińskiego 5, 02-106 Warsaw, Poland
- Correspondence: (G.A.C.); (J.B.S.); Tel.: +48-22-6086-600 (G.A.C.); +48-22-6086-414 (J.B.S.)
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14
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Lotke R, Schneeweiß U, Pietrek M, Günther T, Grundhoff A, Weidner-Glunde M, Schulz TF. Brd/BET Proteins Influence the Genome-Wide Localization of the Kaposi's Sarcoma-Associated Herpesvirus and Murine Gammaherpesvirus Major Latency Proteins. Front Microbiol 2020; 11:591778. [PMID: 33193257 PMCID: PMC7642799 DOI: 10.3389/fmicb.2020.591778] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 09/28/2020] [Indexed: 01/22/2023] Open
Abstract
The rhadinoviruses Kaposi’s Sarcoma-associated herpesvirus (KSHV) and murine gammaherpesvirus (MHV-68) persist in infected hosts in a latent state that is characterized by the absence of virus production and by restricted viral gene expression. Their major latency protein, the latency-associated nuclear antigen (kLANA for KSHV and mLANA for MHV-68), is essential for viral genome maintenance and replication and involved in transcriptional regulation. Both kLANA and mLANA interact with cellular chromatin-associated proteins, among them the Bromodomain and Extra Terminal domain (Brd/BET) proteins, which recruit cellular and viral proteins to acetylated histones through their bromodomains and modulate cellular gene expression. Brd/BET proteins also play a role in the tethering, replication, segregation or integration of a diverse group of viral DNA genomes. In this study we explored if Brd/BET proteins influence the localization of the LANAs to preferential regions in the host chromatin and thereby contribute to kLANA- or mLANA-mediated transcriptional regulation. Using ChIP-Seq, we revealed a genome-wide co-enrichment of kLANA with Brd2/4 near cellular and viral transcriptional start sites (TSS). Treatment with I-BET151, an inhibitor of Brd/BET, displaced kLANA and Brd2/4 from TSS in the viral and host chromatin, but did not affect the direct binding of kLANA to kLANA-binding sites (LBS) in the KSHV latent origin of replication. Similarly, mLANA, but not a mLANA mutant deficient for binding to Brd2/4, also associated with cellular TSS. We compared the transcriptome of KSHV-infected with uninfected and kLANA-expressing human B cell lines, as well as a murine B cell line expressing mLANA or a Brd2/4-binding deficient mLANA mutant. We found that only a minority of cellular genes, whose TSS are occupied by kLANA or mLANA, is transcriptionally regulated by these latency proteins. Our findings extend previous reports on a preferential deposition of kLANA on cellular TSS and show that this characteristic chromatin association pattern is at least partially determined by the interaction of these viral latency proteins with members of the Brd/BET family of chromatin modulators.
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Affiliation(s)
- Rishikesh Lotke
- Institut für Virologie, Medizinische Hochschule Hannover, Hanover, Germany.,German Center for Infection Research, Hannover-Braunschweig and Hamburg Sites, Hanover, Germany
| | - Ulrike Schneeweiß
- Institut für Virologie, Medizinische Hochschule Hannover, Hanover, Germany
| | - Marcel Pietrek
- Institut für Virologie, Medizinische Hochschule Hannover, Hanover, Germany
| | - Thomas Günther
- Heinrich-Pette-Institut, Leibniz-Institut für Experimentelle Virologie, Hamburg, Germany
| | - Adam Grundhoff
- German Center for Infection Research, Hannover-Braunschweig and Hamburg Sites, Hanover, Germany.,Heinrich-Pette-Institut, Leibniz-Institut für Experimentelle Virologie, Hamburg, Germany
| | - Magdalena Weidner-Glunde
- Institut für Virologie, Medizinische Hochschule Hannover, Hanover, Germany.,German Center for Infection Research, Hannover-Braunschweig and Hamburg Sites, Hanover, Germany
| | - Thomas F Schulz
- Institut für Virologie, Medizinische Hochschule Hannover, Hanover, Germany.,German Center for Infection Research, Hannover-Braunschweig and Hamburg Sites, Hanover, Germany
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15
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Duan Z, Han Y, Zhou L, Yuan C, Wang Y, Zhao C, Tang H, Chen J. Chicken bromodomain-containing protein 2 interacts with the Newcastle disease virus matrix protein and promotes viral replication. Vet Res 2020; 51:120. [PMID: 32962745 PMCID: PMC7509934 DOI: 10.1186/s13567-020-00846-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 09/10/2020] [Indexed: 12/23/2022] Open
Abstract
Bromodomain-containing protein 2 (BRD2) is a nucleus-localized serine-threonine kinase that plays pivotal roles in the transcriptional control of diverse genes. In our previous study, the chicken BRD2 (chBRD2) protein was found to interact with the Newcastle disease virus (NDV) matrix (M) protein using a yeast two-hybrid screening system, but the role of the chBRD2 protein in the replication of NDV remains unclear. In this study, we first confirmed the interaction between the M protein and chBRD2 protein using fluorescence co-localization, co-immunoprecipitation and pull-down assays. Intracellular binding studies indicated that the C-terminus (aa 264-313) of the M protein and the extra-terminal (ET) domain (aa 619-683) of the chBRD2 protein were responsible for interactions with each other. Interestingly, although two amino acids (T621 and S649) found in the chBRD2/ET domain were different from those in the human BRD2/ET domain and in that of other mammals, they did not disrupt the BRD2-M interaction or the chBRD2-M interaction. In addition, we found that the transcription of the chBRD2 gene was obviously decreased in both NDV-infected cells and pEGFP-M-transfected cells in a dose-dependent manner. Moreover, small interfering RNA-mediated knockdown of chBRD2 or overexpression of chBRD2 remarkably enhanced or reduced NDV replication by upregulating or downregulating viral RNA synthesis and transcription, respectively. Overall, we demonstrate for the first time that the interaction of the M protein with the chBRD2 protein in the nucleus promotes NDV replication by downregulating chBRD2 expression and facilitating viral RNA synthesis and transcription. These results will provide further insight into the biological functions of the M protein in the replication of NDV.
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Affiliation(s)
- Zhiqiang Duan
- Key Laboratory of Animal Genetics, Breeding and Reproduction in the Plateau Mountainous Region, Ministry of Education, Guizhou University, Guiyang, China. .,College of Animal Science, Guizhou University, Jiaxiu South Road, Huaxi District, Guiyang, 550025, Guizhou, China.
| | - Yifan Han
- College of Animal Science, Guizhou University, Jiaxiu South Road, Huaxi District, Guiyang, 550025, Guizhou, China
| | - Lei Zhou
- College of Animal Science, Guizhou University, Jiaxiu South Road, Huaxi District, Guiyang, 550025, Guizhou, China
| | - Chao Yuan
- College of Animal Science, Guizhou University, Jiaxiu South Road, Huaxi District, Guiyang, 550025, Guizhou, China
| | - Yanbi Wang
- College of Animal Science, Guizhou University, Jiaxiu South Road, Huaxi District, Guiyang, 550025, Guizhou, China
| | - Caiqin Zhao
- College of Animal Science, Guizhou University, Jiaxiu South Road, Huaxi District, Guiyang, 550025, Guizhou, China
| | - Hong Tang
- College of Animal Science, Guizhou University, Jiaxiu South Road, Huaxi District, Guiyang, 550025, Guizhou, China
| | - Jiaqi Chen
- College of Animal Science, Guizhou University, Jiaxiu South Road, Huaxi District, Guiyang, 550025, Guizhou, China
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16
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Design, synthesis and biological evaluation of novel 6-phenyl-1,3a,4,10b-tetrahydro-2H-benzo[c]thiazolo[4,5-e]azepin-2-one derivatives as potential BRD4 inhibitors. Bioorg Med Chem 2020; 28:115601. [DOI: 10.1016/j.bmc.2020.115601] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 06/16/2020] [Accepted: 06/16/2020] [Indexed: 12/20/2022]
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17
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Liang D, Yu Y, Ma Z. Novel strategies targeting bromodomain-containing protein 4 (BRD4) for cancer drug discovery. Eur J Med Chem 2020; 200:112426. [DOI: 10.1016/j.ejmech.2020.112426] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/28/2020] [Accepted: 05/05/2020] [Indexed: 12/13/2022]
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18
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Bechter O, Schöffski P. Make your best BET: The emerging role of BET inhibitor treatment in malignant tumors. Pharmacol Ther 2020; 208:107479. [PMID: 31931101 DOI: 10.1016/j.pharmthera.2020.107479] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 11/15/2019] [Indexed: 12/17/2022]
Abstract
Bromodomains are protein-protein interaction modules with a great diversity in terms of number of proteins and their function. The bromodomain and extraterminal protein (BET) represents a distinct subclass of bromodomain proteins mainly involved in transcriptional regulation via their interaction with acetylated chromatin. In cancer cells BET proteins are found to be altered in many ways such as overexpression, mutations and fusions of BET proteins or their interference with cancer relevant signaling pathways and transcriptional programs in order to sustain cancer growth and viability. Blocking BET protein function with small molecules is associated with therapeutic activity. Consequently, a variety of small molecules have been developed and a number of phase I clinical trials have explored their tolerability and efficacy in patients with solid tumors and hematological malignancies. We will review the rational for applying BET inhibitors in the clinic and we will discuss the toxicity profile as well as efficacy of this new class of protein inhibitors. We will also highlight the emerging problem of treatment resistance and the potential these drugs might have when combined with other anti-cancer therapies.
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Affiliation(s)
- Oliver Bechter
- Leuven Cancer Institute, Department of General Medical Oncology, University Hospitals Leuven, Belgium; Department of Oncology, KU, Leuven, Belgium.
| | - Patrick Schöffski
- Leuven Cancer Institute, Department of General Medical Oncology, University Hospitals Leuven, Belgium; Department of Oncology, KU, Leuven, Belgium.
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19
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Izumikawa K, Ishikawa H, Yoshikawa H, Fujiyama S, Watanabe A, Aburatani H, Tachikawa H, Hayano T, Miura Y, Isobe T, Simpson RJ, Li L, Min J, Takahashi N. LYAR potentiates rRNA synthesis by recruiting BRD2/4 and the MYST-type acetyltransferase KAT7 to rDNA. Nucleic Acids Res 2019; 47:10357-10372. [PMID: 31504794 PMCID: PMC6821171 DOI: 10.1093/nar/gkz747] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 07/22/2019] [Accepted: 08/20/2018] [Indexed: 02/06/2023] Open
Abstract
Activation of ribosomal RNA (rRNA) synthesis is pivotal during cell growth and proliferation, but its aberrant upregulation may promote tumorigenesis. Here, we demonstrate that the candidate oncoprotein, LYAR, enhances ribosomal DNA (rDNA) transcription. Our data reveal that LYAR binds the histone-associated protein BRD2 without involvement of acetyl-lysine-binding bromodomains and recruits BRD2 to the rDNA promoter and transcribed regions via association with upstream binding factor. We show that BRD2 is required for the recruitment of the MYST-type acetyltransferase KAT7 to rDNA loci, resulting in enhanced local acetylation of histone H4. In addition, LYAR binds a complex of BRD4 and KAT7, which is then recruited to rDNA independently of the BRD2-KAT7 complex to accelerate the local acetylation of both H4 and H3. BRD2 also helps recruit BRD4 to rDNA. By contrast, LYAR has no effect on rDNA methylation or the binding of RNA polymerase I subunits to rDNA. These data suggest that LYAR promotes the association of the BRD2-KAT7 and BRD4-KAT7 complexes with transcription-competent rDNA loci but not to transcriptionally silent rDNA loci, thereby increasing rRNA synthesis by altering the local acetylation status of histone H3 and H4.
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Affiliation(s)
- Keiichi Izumikawa
- Department of Applied Life Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan.,Global Innovation Research Organizations, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
| | - Hideaki Ishikawa
- Department of Applied Life Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan
| | - Harunori Yoshikawa
- Centre for Gene Regulation & Expression, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Sally Fujiyama
- Department of Applied Life Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan
| | - Akira Watanabe
- Department of Life Science Frontiers, Center for iPS Cell Research and Application, Kyoto University 53, Shogoin-kawahara-cho, Sakyo-ku, Kyoto-shi, Kyoto 606-8507, Japan
| | - Hiroyuki Aburatani
- Laboratory for System Biology and Medicine, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
| | - Hiroyuki Tachikawa
- Department of Applied Life Science, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Toshiya Hayano
- Department of Biomedical Sciences, College of Life Sciences, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu 525-8577, Japan
| | - Yutaka Miura
- Department of Applied Life Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan.,Global Innovation Research Organizations, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
| | - Toshiaki Isobe
- Department of Chemistry, Graduate School of Sciences and Engineering, Tokyo Metropolitan University, 1-1 Minamiosawa, Hachiouji-shi, Tokyo 192-0397, Japan
| | - Richard J Simpson
- Global Innovation Research Organizations, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan.,La Trobe Institute for Molecular Science (LIMS) LIMS Building 1, Room 412 La Trobe University, Bundoora Victoria 3086, Australia
| | - Li Li
- Structural Genomics Consortium, University of Toronto, 101 College St., Toronto, Ontario M5G 1L7, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Jinrong Min
- Global Innovation Research Organizations, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan.,Structural Genomics Consortium, University of Toronto, 101 College St., Toronto, Ontario M5G 1L7, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Nobuhiro Takahashi
- Department of Applied Life Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo 183-8509, Japan.,Global Innovation Research Organizations, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo 183-8509, Japan
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20
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Zong J, Li S, Wang Y, Mo W, Sun R, Yu M. Bromodomain-containing protein 2 promotes lipolysis via ERK/HSL signalling pathway in white adipose tissue of mice. Gen Comp Endocrinol 2019; 281:105-116. [PMID: 31121164 DOI: 10.1016/j.ygcen.2019.05.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 04/17/2019] [Accepted: 05/14/2019] [Indexed: 01/10/2023]
Abstract
White adipose tissue (WAT) dysfunction is prevalent among patients with type 2 diabetes mellitus (T2DM). Uncontrolled free fatty acid (FFA) release from WAT stores has detrimental effects on lipid metabolism, leading to insulin resistance. Bromodomain-containing protein 2 (Brd2) has emerged as a central transcriptional regulator of adipocyte differentiation and pancreatic β-cell bioactivity. A recent study shows that Brd2 overexpression leads to insulin resistance in mice. However, the mechanisms underlying these effects have not been fully elucidated. This study provides the first evidence that adenoviral-mediated Brd2 overexpression in the WAT of mice increases lipolysis-related gene expression in addition to significantly reducing WAT size and promoting plasma FFA release. Brd2 overexpression in adipocytes also inhibits fat synthesis-related gene expression, while activating hormone-sensitive lipase (HSL) expression and ERK-dependent perilipin 1 inhibition as well as promoting glycerol release, which are all involved in lipolysis. Collectively, these results indicate that Brd2 triggers insulin resistance via lipolysis-mediated FFA release.
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Affiliation(s)
- Jiuyu Zong
- The Key Laboratory of Metabolism and Molecular Medicine, The Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Science, Fudan University, Shanghai 200032, China
| | - Shuting Li
- The Key Laboratory of Metabolism and Molecular Medicine, The Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Science, Fudan University, Shanghai 200032, China
| | - Yuxiong Wang
- The Key Laboratory of Metabolism and Molecular Medicine, The Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Science, Fudan University, Shanghai 200032, China
| | - Wei Mo
- The Key Laboratory of Metabolism and Molecular Medicine, The Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Science, Fudan University, Shanghai 200032, China
| | - Ruixin Sun
- State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200032, China.
| | - Min Yu
- The Key Laboratory of Metabolism and Molecular Medicine, The Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Science, Fudan University, Shanghai 200032, China.
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21
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Andrieu GP, Shafran JS, Deeney JT, Bharadwaj KR, Rangarajan A, Denis GV. BET proteins in abnormal metabolism, inflammation, and the breast cancer microenvironment. J Leukoc Biol 2018; 104:265-274. [PMID: 29493812 PMCID: PMC6134394 DOI: 10.1002/jlb.5ri0917-380rr] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 02/10/2018] [Accepted: 02/10/2018] [Indexed: 12/21/2022] Open
Abstract
Obesity and its associated pathology Type 2 diabetes are two chronic metabolic and inflammatory diseases that promote breast cancer progression, metastasis, and poor outcomes. Emerging critical opinion considers unresolved inflammation and abnormal metabolism separately from obesity; settings where they do not co-occur can inform disease mechanism. In breast cancer, the tumor microenvironment is often infiltrated with T effector and T regulatory cells programmed by metabolic signaling. The pathways by which tumor cells evade immune surveillance, immune therapies, and take advantage of antitumor immunity are poorly understood, but likely depend on metabolic inflammation in the microenvironment. Immune functions are abnormal in metabolic disease, and lessons learned from preclinical studies in lean and metabolically normal environments may not translate to patients with obesity and metabolic disease. This problem is made more urgent by the rising incidence of breast cancer among women who are not obese but who have metabolic disease and associated inflammation, a phenotype common in Asia. The somatic BET proteins, comprising BRD2, BRD3, and BRD4, are new critical regulators of metabolism, coactivate transcription of genes that encode proinflammatory cytokines in immune cell subsets infiltrating the microenvironment, and could be important targets in breast cancer immunotherapy. These transcriptional coregulators are well known to regulate tumor cell progression, but only recently identified as critical for metabolism, metastasis, and expression of immune checkpoint molecules. We consider interrelationships among metabolism, inflammation, and breast cancer aggressiveness relevant to the emerging threat of breast cancer among women with metabolic disease, but without obesity.
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Affiliation(s)
| | - Jordan S. Shafran
- Cancer Center, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Jude T. Deeney
- Department of Medicine, Section of Endocrinology, Obesity Research Center, Evans Biomedical Research Center; Boston University School of Medicine, Boston, Massachusetts, USA
| | - Kishan R. Bharadwaj
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bengaluru, India
| | - Annapoorni Rangarajan
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bengaluru, India
| | - Gerald V. Denis
- Cancer Center, Boston University School of Medicine, Boston, Massachusetts, USA
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22
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Targetable BET proteins- and E2F1-dependent transcriptional program maintains the malignancy of glioblastoma. Proc Natl Acad Sci U S A 2018; 115:E5086-E5095. [PMID: 29764999 DOI: 10.1073/pnas.1712363115] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Competitive BET bromodomain inhibitors (BBIs) targeting BET proteins (BRD2, BRD3, BRD4, and BRDT) show promising preclinical activities against brain cancers. However, the BET protein-dependent glioblastoma (GBM)-promoting transcriptional network remains elusive. Here, with mechanistic exploration of a next-generation chemical degrader of BET proteins (dBET6), we reveal a profound and consistent impact of BET proteins on E2F1- dependent transcriptional program in both differentiated GBM cells and brain tumor-initiating cells. dBET6 treatment drastically reduces BET protein genomic occupancy, RNA-Pol2 activity, and permissive chromatin marks. Subsequently, dBET6 represses the proliferation, self-renewal, and tumorigenic ability of GBM cells. Moreover, dBET6-induced degradation of BET proteins exerts superior antiproliferation effects compared to conventional BBIs and overcomes both intrinsic and acquired resistance to BBIs in GBM cells. Our study reveals crucial functions of BET proteins and provides the rationale and therapeutic merits of targeted degradation of BET proteins in GBM.
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23
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Liu Z, Wang P, Chen H, Wold EA, Tian B, Brasier AR, Zhou J. Drug Discovery Targeting Bromodomain-Containing Protein 4. J Med Chem 2017; 60:4533-4558. [PMID: 28195723 PMCID: PMC5464988 DOI: 10.1021/acs.jmedchem.6b01761] [Citation(s) in RCA: 215] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
![]()
BRD4,
the most extensively studied member of the BET family, is
an epigenetic regulator that localizes to DNA via binding to acetylated
histones and controls the expression of therapeutically important
gene regulatory networks through the recruitment of transcription
factors to form mediator complexes, phosphorylating RNA polymerase
II, and by its intrinsic histone acetyltransferase activity. Disrupting
the protein–protein interactions between BRD4 and acetyl-lysine
has been shown to effectively block cell proliferation in cancer,
cytokine production in acute inflammation, and so forth. To date,
significant efforts have been devoted to the development of BRD4 inhibitors,
and consequently, a dozen have progressed to human clinical trials.
Herein, we summarize the advances in drug discovery and development
of BRD4 inhibitors by focusing on their chemotypes, in vitro and in
vivo activity, selectivity, relevant mechanisms of action, and therapeutic
potential. Opportunities and challenges to achieve selective and efficacious
BRD4 inhibitors as a viable therapeutic strategy for human diseases
are also highlighted.
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Affiliation(s)
- Zhiqing Liu
- Chemical Biology Program, Department of Pharmacology and Toxicology, ‡Department of Internal Medicine, §Sealy Center for Molecular Medicine, ξInstitute for Translational Sciences, University of Texas Medical Branch , Galveston, Texas 77555, United States
| | - Pingyuan Wang
- Chemical Biology Program, Department of Pharmacology and Toxicology, ‡Department of Internal Medicine, §Sealy Center for Molecular Medicine, ξInstitute for Translational Sciences, University of Texas Medical Branch , Galveston, Texas 77555, United States
| | - Haiying Chen
- Chemical Biology Program, Department of Pharmacology and Toxicology, ‡Department of Internal Medicine, §Sealy Center for Molecular Medicine, ξInstitute for Translational Sciences, University of Texas Medical Branch , Galveston, Texas 77555, United States
| | - Eric A Wold
- Chemical Biology Program, Department of Pharmacology and Toxicology, ‡Department of Internal Medicine, §Sealy Center for Molecular Medicine, ξInstitute for Translational Sciences, University of Texas Medical Branch , Galveston, Texas 77555, United States
| | - Bing Tian
- Chemical Biology Program, Department of Pharmacology and Toxicology, ‡Department of Internal Medicine, §Sealy Center for Molecular Medicine, ξInstitute for Translational Sciences, University of Texas Medical Branch , Galveston, Texas 77555, United States
| | - Allan R Brasier
- Chemical Biology Program, Department of Pharmacology and Toxicology, ‡Department of Internal Medicine, §Sealy Center for Molecular Medicine, ξInstitute for Translational Sciences, University of Texas Medical Branch , Galveston, Texas 77555, United States
| | - Jia Zhou
- Chemical Biology Program, Department of Pharmacology and Toxicology, ‡Department of Internal Medicine, §Sealy Center for Molecular Medicine, ξInstitute for Translational Sciences, University of Texas Medical Branch , Galveston, Texas 77555, United States
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Goupille O, Penglong T, Kadri Z, Granger-Locatelli M, Fucharoen S, Maouche-Chrétien L, Prost S, Leboulch P, Chrétien S. Inhibition of the acetyl lysine-binding pocket of bromodomain and extraterminal domain proteins interferes with adipogenesis. Biochem Biophys Res Commun 2016; 472:624-30. [PMID: 26972250 DOI: 10.1016/j.bbrc.2016.03.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 03/06/2016] [Indexed: 11/26/2022]
Abstract
The bromodomain and extraterminal (BET) domain family proteins are epigenetic modulators involved in the reading of acetylated lysine residues. The first BET protein inhibitor to be identified, (+)-JQ1, a thienotriazolo-1, 4-diazapine, binds selectively to the acetyl lysine-binding pocket of BET proteins. We evaluated the impact on adipogenesis of this druggable targeting of chromatin epigenetic readers, by investigating the physiological consequences of epigenetic modifications through targeting proteins binding to chromatin. JQ1 significantly inhibited the differentiation of 3T3-L1 preadipocytes into white and brown adipocytes by down-regulating the expression of genes involved in adipogenesis, particularly those encoding the peroxisome proliferator-activated receptor (PPAR-γ), the CCAAT/enhancer-binding protein (C/EBPα) and, STAT5A and B. The expression of a constitutively activated STAT5B mutant did not prevent inhibition by JQ1. Thus, the association of BET/STAT5 is required for adipogenesis but STAT5 transcription activity is not the only target of JQ1. Treatment with JQ1 did not lead to the conversion of white adipose tissue into brown adipose tissue (BAT). BET protein inhibition thus interferes with generation of adipose tissue from progenitors, confirming the importance of the connections between epigenetic mechanisms and specific adipogenic transcription factors.
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Affiliation(s)
- Olivier Goupille
- CEA, Institute of Emerging Diseases and Innovative Therapies (IMETI), Fontenay-aux-Roses and Université Paris-Saclay, UMR-E 007, France
| | - Tipparat Penglong
- CEA, Institute of Emerging Diseases and Innovative Therapies (IMETI), Fontenay-aux-Roses and Université Paris-Saclay, UMR-E 007, France; Thalassemia Research Center, Mahidol University, Thailand
| | - Zahra Kadri
- CEA, Institute of Emerging Diseases and Innovative Therapies (IMETI), Fontenay-aux-Roses and Université Paris-Saclay, UMR-E 007, France
| | - Marine Granger-Locatelli
- CEA, Institute of Emerging Diseases and Innovative Therapies (IMETI), Fontenay-aux-Roses and Université Paris-Saclay, UMR-E 007, France
| | | | - Leila Maouche-Chrétien
- CEA, Institute of Emerging Diseases and Innovative Therapies (IMETI), Fontenay-aux-Roses and Université Paris-Saclay, UMR-E 007, France; INSERM, Paris, France
| | - Stéphane Prost
- CEA, Institute of Emerging Diseases and Innovative Therapies (IMETI), Fontenay-aux-Roses and Université Paris-Saclay, UMR-E 007, France
| | - Philippe Leboulch
- CEA, Institute of Emerging Diseases and Innovative Therapies (IMETI), Fontenay-aux-Roses and Université Paris-Saclay, UMR-E 007, France; Thalassemia Research Center, Mahidol University, Thailand
| | - Stany Chrétien
- CEA, Institute of Emerging Diseases and Innovative Therapies (IMETI), Fontenay-aux-Roses and Université Paris-Saclay, UMR-E 007, France; INSERM, Paris, France.
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Alghamdi S, Khan I, Beeravolu N, McKee C, Thibodeau B, Wilson G, Chaudhry GR. BET protein inhibitor JQ1 inhibits growth and modulates WNT signaling in mesenchymal stem cells. Stem Cell Res Ther 2016; 7:22. [PMID: 26830473 PMCID: PMC4736146 DOI: 10.1186/s13287-016-0278-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 12/04/2015] [Accepted: 01/11/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Efficacy and safety of anticancer drugs are traditionally studied using cancer cell lines and animal models. The thienodiazepine class of BET inhibitors, such as JQ1, has been extensively studied for the potential treatment of hematological malignancies and several small molecules belonging to this class are currently under clinical investigation. While these compounds are well known to inhibit cancer cell growth and cause apoptosis, their effects on stem cells, particularly mesenchymal stem cells (MSCs), which are important for regeneration of damaged cells and tissues, are unknown. In this study we employed umbilical cord derived MSCs as a model system to evaluate the safety of JQ1. METHODS Cord derived MSCs were treated with various doses of JQ1 and subjected to cell metabolic activity, apoptosis, and cell cycle analyses using MTT assay, Annexin-V/FITC and PI staining, and flow cytometry, respectively. The effect of JQ1 on gene expression was determined using microarray and quantitative real-time reverse transcriptase polymerase chain reaction analysis. Furthermore, protein expression of apoptotic and neuronal markers was carried out using western blot and immunostaining, respectively. RESULTS Our results showed that JQ1 inhibited cell growth and caused cell cycle arrest in G1 phase but did not induce apoptosis or senescence. JQ1 also down-regulated genes involved in self-renewal, cell cycle, DNA replication, and mitosis, which may have negative implications on the regenerative potential of MSCs. In addition, JQ1 interfered with signaling pathways by down regulating the expression of WNT, resulting in limiting the self-renewal. These results suggest that anticancer agents belonging to the thienodiazepine class of BET inhibitors should be carefully evaluated before their use in cancer therapy. CONCLUSIONS This study revealed for the first time that JQ1 adversely affected MSCs, which are important for repair and regeneration. JQ1 specifically modulated signal transduction and inhibited growth as well as self-renewal. These findings suggest that perinatal MSCs could be used to supplement animal models for investigating the safety of anticancer agents and other drugs.
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Affiliation(s)
- Saeed Alghamdi
- Department of Biological Sciences, Oakland University, Rochester, MI, 48309, USA. .,OU-WB Institute for Stem Cell and Regenerative Medicine, Oakland University, Rochester, MI, 48309, USA.
| | - Irfan Khan
- Department of Biological Sciences, Oakland University, Rochester, MI, 48309, USA. .,OU-WB Institute for Stem Cell and Regenerative Medicine, Oakland University, Rochester, MI, 48309, USA.
| | - Naimisha Beeravolu
- Department of Biological Sciences, Oakland University, Rochester, MI, 48309, USA. .,OU-WB Institute for Stem Cell and Regenerative Medicine, Oakland University, Rochester, MI, 48309, USA.
| | - Christina McKee
- Department of Biological Sciences, Oakland University, Rochester, MI, 48309, USA. .,OU-WB Institute for Stem Cell and Regenerative Medicine, Oakland University, Rochester, MI, 48309, USA.
| | | | - George Wilson
- OU-WB Institute for Stem Cell and Regenerative Medicine, Oakland University, Rochester, MI, 48309, USA. .,Beaumont Health System, Royal Oak, MI, 48073, USA.
| | - G Rasul Chaudhry
- Department of Biological Sciences, Oakland University, Rochester, MI, 48309, USA. .,OU-WB Institute for Stem Cell and Regenerative Medicine, Oakland University, Rochester, MI, 48309, USA.
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H2A.Z.1 Monoubiquitylation Antagonizes BRD2 to Maintain Poised Chromatin in ESCs. Cell Rep 2016; 14:1142-1155. [PMID: 26804911 DOI: 10.1016/j.celrep.2015.12.100] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 10/16/2015] [Accepted: 12/22/2015] [Indexed: 12/13/2022] Open
Abstract
Histone variant H2A.Z occupies the promoters of active and poised, bivalent genes in embryonic stem cells (ESCs) to regulate developmental programs, yet how it contributes to these contrasting states is poorly understood. Here, we investigate the function of H2A.Z.1 monoubiquitylation (H2A.Z.1ub) by mutation of the PRC1 target residues (H2A.Z.1(K3R3)). We show that H2A.Z.1(K3R3) is properly incorporated at target promoters in murine ESCs (mESCs), but loss of monoubiquitylation leads to de-repression of bivalent genes, loss of Polycomb binding, and faulty lineage commitment. Using quantitative proteomics, we find that tandem bromodomain proteins, including the BET family member BRD2, are enriched in H2A.Z.1 chromatin. We further show that BRD2 is gained at de-repressed promoters in H2A.Z.1(K3R3) mESCs, whereas BRD2 inhibition restores gene silencing at these sites. Together, our study reveals an antagonistic relationship between H2A.Z.1ub and BRD2 to regulate the transcriptional balance at bivalent genes to enable proper execution of developmental programs.
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27
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Wang L, Wolgemuth DJ. BET Protein BRDT Complexes With HDAC1, PRMT5, and TRIM28 and Functions in Transcriptional Repression During Spermatogenesis. J Cell Biochem 2015; 117:1429-38. [PMID: 26565999 DOI: 10.1002/jcb.25433] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 11/10/2015] [Indexed: 02/01/2023]
Abstract
The expression of BRDT, a member of the BET sub-family of double bromodomain-containing proteins, is restricted to the male germ line, specifically to pachytene-diplotene spermatocytes and early spermatids. We previously showed that loss of the first bromodomain of BRDT by targeted mutagenesis (Brdt(ΔBD1) ) resulted in sterility and abnormalities in spermiogenesis, but little is known about BRDT's function at the molecular level. As part of studies designed to identify BRDT-interacting proteins we stably introduced a FLAG-tagged BRDT cDNA into 293T cells, which do not normally express BRDT. Affinity-purification of FLAG-tagged BRDT complexes indicated that BRDT has novel interactions with the histone deacetylase HDAC1, the arginine-specific histone methyltransferase 5 PRMT5, and the Tripartite motif-containing 28 protein TRIM28. Immunofluorescent microscopy revealed that BRDT co-localized with each of these proteins in round spermatids and co-immunoprecipitation of testicular extracts showed that these proteins interact with BRDT. Furthermore, they bind the promoter of H1t, a putative target of BRDT-containing complexes. This binding of H1t was lost in mice expressing the Brdt(ΔBD1) mutant protein and concomitantly, H1t expression was elevated in round spermatids. Our study reveals a role for BRDT-containing complexes in the repression of gene expression in vivo that correlates with dramatic effects on chromatin remodeling and the progression of spermiogenesis.
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Affiliation(s)
- Li Wang
- Department of Genetics and Development, New York, New York, 10032
| | - Debra J Wolgemuth
- Department of Genetics and Development, New York, New York, 10032.,Department of Obstetrics and Gynecology, New York, New York, 10032.,Institute of Human Nutrition, New York, New York, 10032.,Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, New York, 10032
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28
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Pinz S, Unser S, Buob D, Fischer P, Jobst B, Rascle A. Deacetylase inhibitors repress STAT5-mediated transcription by interfering with bromodomain and extra-terminal (BET) protein function. Nucleic Acids Res 2015; 43:3524-45. [PMID: 25769527 PMCID: PMC4402521 DOI: 10.1093/nar/gkv188] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Accepted: 02/23/2015] [Indexed: 12/21/2022] Open
Abstract
Signal transducer and activator of transcription STAT5 is essential for the regulation of proliferation and survival genes. Its activity is tightly regulated through cytokine signaling and is often upregulated in cancer. We showed previously that the deacetylase inhibitor trichostatin A (TSA) inhibits STAT5-mediated transcription by preventing recruitment of the transcriptional machinery at a step following STAT5 binding to DNA. The mechanism and factors involved in this inhibition remain unknown. We now show that deacetylase inhibitors do not target STAT5 acetylation, as we initially hypothesized. Instead, they induce a rapid increase in global histone acetylation apparently resulting in the delocalization of the bromodomain and extra-terminal (BET) protein Brd2 and of the Brd2-associated factor TBP to hyperacetylated chromatin. Treatment with the BET inhibitor (+)-JQ1 inhibited expression of STAT5 target genes, supporting a role of BET proteins in the regulation of STAT5 activity. Accordingly, chromatin immunoprecipitation demonstrated that Brd2 is associated with the transcriptionally active STAT5 target gene Cis and is displaced upon TSA treatment. Our data therefore indicate that Brd2 is required for the proper recruitment of the transcriptional machinery at STAT5 target genes and that deacetylase inhibitors suppress STAT5-mediated transcription by interfering with Brd2 function.
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Affiliation(s)
- Sophia Pinz
- Stat5 Signaling Research Group, Institute of Immunology, University of Regensburg, 93053 Regensburg, Germany
| | - Samy Unser
- Stat5 Signaling Research Group, Institute of Immunology, University of Regensburg, 93053 Regensburg, Germany
| | - Dominik Buob
- Stat5 Signaling Research Group, Institute of Immunology, University of Regensburg, 93053 Regensburg, Germany
| | - Philipp Fischer
- Stat5 Signaling Research Group, Institute of Immunology, University of Regensburg, 93053 Regensburg, Germany
| | - Belinda Jobst
- Stat5 Signaling Research Group, Institute of Immunology, University of Regensburg, 93053 Regensburg, Germany
| | - Anne Rascle
- Stat5 Signaling Research Group, Institute of Immunology, University of Regensburg, 93053 Regensburg, Germany
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29
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Poppy Roworth A, Ghari F, La Thangue NB. To live or let die - complexity within the E2F1 pathway. Mol Cell Oncol 2015; 2:e970480. [PMID: 27308406 PMCID: PMC4905241 DOI: 10.4161/23723548.2014.970480] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 09/11/2014] [Accepted: 09/11/2014] [Indexed: 04/21/2023]
Abstract
The E2F1 transcription factor is a recognized regulator of the cell cycle as well as a potent mediator of DNA damage-induced apoptosis and the checkpoint response. Understanding the diverse and seemingly dichotomous functions of E2F1 activity has been the focus of extensive ongoing research. Although the E2F pathway is frequently deregulated in cancer, the contributions of E2F1 itself to tumorigenesis, as a promoter of proliferation or cell death, are far from understood. In this review we aim to provide an update on our current understanding of E2F1, with particular insight into its novel interaction partners and post-translational modifications, as a means to explaining its diverse functional complexity.
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Affiliation(s)
- A Poppy Roworth
- Laboratory of Cancer Biology; Department of Oncology; University of Oxford; Oxford, UK
| | - Fatemeh Ghari
- Laboratory of Cancer Biology; Department of Oncology; University of Oxford; Oxford, UK
| | - Nicholas B La Thangue
- Laboratory of Cancer Biology; Department of Oncology; University of Oxford; Oxford, UK
- Correspondence to: Nicholas B La Thangue;
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30
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tBRD-1 selectively controls gene activity in the Drosophila testis and interacts with two new members of the bromodomain and extra-terminal (BET) family. PLoS One 2014; 9:e108267. [PMID: 25251222 PMCID: PMC4177214 DOI: 10.1371/journal.pone.0108267] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 08/04/2014] [Indexed: 01/29/2023] Open
Abstract
Multicellular organisms have evolved specialized mechanisms to control transcription in a spatial and temporal manner. Gene activation is tightly linked to histone acetylation on lysine residues that can be recognized by bromodomains. Previously, the testis-specifically expressed bromodomain protein tBRD-1 was identified in Drosophila. Expression of tBRD-1 is restricted to highly transcriptionally active primary spermatocytes. tBRD-1 is essential for male fertility and proposed to act as a co-factor of testis-specific TATA box binding protein-associated factors (tTAFs) for testis-specific transcription. Here, we performed microarray analyses to compare the transcriptomes of tbrd-1 mutant testes and wild-type testes. Our data confirmed that tBRD-1 controls gene activity in male germ cells. Additionally, comparing the transcriptomes of tbrd-1 and tTAF mutant testes revealed a subset of common target genes. We also characterized two new members of the bromodomain and extra-terminal (BET) family, tBRD-2 and tBRD-3. In contrast to other members of the BET family in animals, both possess only a single bromodomain, a characteristic feature of plant BET family members. Immunohistology techniques not only revealed that tBRD-2 and tBRD-3 partially co-localize with tBRD-1 and tTAFs in primary spermatocytes, but also that their proper subcellular distribution was impaired in tbrd-1 and tTAF mutant testes. Treating cultured male germ cells with inhibitors showed that localization of tBRD-2 and tBRD-3 depends on the acetylation status within primary spermatocytes. Yeast two-hybrid assays and co-immunoprecipitations using fly testes protein extracts demonstrated that tBRD-1 is able to form homodimers as well as heterodimers with tBRD-2, tBRD-3, and tTAFs. These data reveal for the first time the existence of single bromodomain BET proteins in animals, as well as evidence for a complex containing tBRDs and tTAFs that regulates transcription of a subset of genes with relevance for spermiogenesis.
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31
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Chapuy B, McKeown MR, Lin CY, Monti S, Roemer MGM, Qi J, Rahl PB, Sun HH, Yeda KT, Doench JG, Reichert E, Kung AL, Rodig SJ, Young RA, Shipp MA, Bradner JE. Discovery and characterization of super-enhancer-associated dependencies in diffuse large B cell lymphoma. Cancer Cell 2013; 24:777-90. [PMID: 24332044 PMCID: PMC4018722 DOI: 10.1016/j.ccr.2013.11.003] [Citation(s) in RCA: 583] [Impact Index Per Article: 53.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 09/17/2013] [Accepted: 11/06/2013] [Indexed: 01/17/2023]
Abstract
Diffuse large B cell lymphoma (DLBCL) is a biologically heterogeneous and clinically aggressive disease. Here, we explore the role of bromodomain and extra-terminal domain (BET) proteins in DLBCL, using integrative chemical genetics and functional epigenomics. We observe highly asymmetric loading of bromodomain 4 (BRD4) at enhancers, with approximately 33% of all BRD4 localizing to enhancers at 1.6% of occupied genes. These super-enhancers prove particularly sensitive to bromodomain inhibition, explaining the selective effect of BET inhibitors on oncogenic and lineage-specific transcriptional circuits. Functional study of genes marked by super-enhancers identifies DLBCLs dependent on OCA-B and suggests a strategy for discovering unrecognized cancer dependencies. Translational studies performed on a comprehensive panel of DLBCLs establish a therapeutic rationale for evaluating BET inhibitors in this disease.
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Affiliation(s)
- Bjoern Chapuy
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - Michael R McKeown
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - Charles Y Lin
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - Stefano Monti
- Section of Computational Biomedicine, Boston University School of Medicine, Boston, MA 02118, USA
| | | | - Jun Qi
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - Peter B Rahl
- Whitehead Institute of Genome Research, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Heather H Sun
- Department of Pathology, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Kelly T Yeda
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | | | - Elaine Reichert
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - Andrew L Kung
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - Scott J Rodig
- Department of Pathology, Brigham and Women's Hospital, Boston, MA 02115, USA
| | - Richard A Young
- Whitehead Institute of Genome Research, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Margaret A Shipp
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA.
| | - James E Bradner
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA.
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32
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Gupta SS, Maetzig T, Maertens GN, Sharif A, Rothe M, Weidner-Glunde M, Galla M, Schambach A, Cherepanov P, Schulz TF. Bromo- and extraterminal domain chromatin regulators serve as cofactors for murine leukemia virus integration. J Virol 2013; 87:12721-36. [PMID: 24049186 PMCID: PMC3838128 DOI: 10.1128/jvi.01942-13] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 09/09/2013] [Indexed: 01/03/2023] Open
Abstract
Retroviral integrase (IN) proteins catalyze the permanent integration of proviral genomes into host DNA with the help of cellular cofactors. Lens epithelium-derived growth factor (LEDGF) is a cofactor for lentiviruses, including human immunodeficiency virus type 1 (HIV-1), and targets lentiviral integration toward active transcription units in the host genome. In contrast to lentiviruses, murine leukemia virus (MLV), a gammaretrovirus, tends to integrate near transcription start sites. Here, we show that the bromodomain and extraterminal domain (BET) proteins BRD2, BRD3, and BRD4 interact with gammaretroviral INs and stimulate the catalytic activity of MLV IN in vitro. We mapped the interaction site to a characteristic structural feature within the BET protein extraterminal (ET) domain and to three amino acids in MLV IN. The ET domains of different BET proteins stimulate MLV integration in vitro and, in the case of BRD2, also in vivo. Furthermore, two small-molecule BET inhibitors, JQ1 and I-BET, decrease MLV integration and shift it away from transcription start sites. Our data suggest that BET proteins might act as chromatin-bound acceptors for the MLV preintegration complex. These results could pave a way to redirecting MLV DNA integration as a basis for creating safer retroviral vectors.
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Affiliation(s)
| | - Tobias Maetzig
- Institute of Experimental Hematology, Hannover Medical School, Hannover, Germany
| | - Goedele N. Maertens
- Division of Medicine, St. Mary's Campus, Imperial College London, London, United Kingdom
| | - Azar Sharif
- Division of Medicine, St. Mary's Campus, Imperial College London, London, United Kingdom
| | - Michael Rothe
- Institute of Experimental Hematology, Hannover Medical School, Hannover, Germany
| | | | - Melanie Galla
- Institute of Experimental Hematology, Hannover Medical School, Hannover, Germany
| | - Axel Schambach
- Institute of Experimental Hematology, Hannover Medical School, Hannover, Germany
- Division of Hematology/Oncology, Children's Hospital Boston, Harvard Medical School, Boston, Massachusetts, USA
| | - Peter Cherepanov
- Division of Medicine, St. Mary's Campus, Imperial College London, London, United Kingdom
- Chromatin Structure and Mobile DNA Laboratory, Cancer Research UK, Herts, United Kingdom
| | - Thomas F. Schulz
- Institute of Virology, Hannover Medical School, Hannover, Germany
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Hnilicová J, Hozeifi S, Stejskalová E, Dušková E, Poser I, Humpolíčková J, Hof M, Staněk D. The C-terminal domain of Brd2 is important for chromatin interaction and regulation of transcription and alternative splicing. Mol Biol Cell 2013; 24:3557-68. [PMID: 24048450 PMCID: PMC3826993 DOI: 10.1091/mbc.e13-06-0303] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
This study determines genes that are regulated by Brd2 and finds that, in addition to expression control, Brd2 modulates the alternative splicing of several hundred genes. The in vivo interaction of Brd2 with chromatin is analyzed, and the contributions of individual Brd2 domains to the chromatin interaction are determined. Brd2 is a member of the bromodomain extra terminal (BET) protein family, which consists of four chromatin-interacting proteins that regulate gene expression. Each BET protein contains two N-terminal bromodomains, which recognize acetylated histones, and the C-terminal protein–protein interaction domain. Using a genome-wide screen, we identify 1450 genes whose transcription is regulated by Brd2. In addition, almost 290 genes change their alternative splicing pattern upon Brd2 depletion. Brd2 is specifically localized at promoters of target genes, and our data show that Brd2 interaction with chromatin cannot be explained solely by histone acetylation. Using coimmunoprecipitation and live-cell imaging, we show that the C-terminal part is crucial for Brd2 association with chromatin. Live-cell microscopy also allows us to map the average binding time of Brd2 to chromatin and quantify the contributions of individual Brd2 domains to the interaction with chromatin. Finally, we show that bromodomains and the C-terminal domain are equally important for transcription and splicing regulation, which correlates with the role of these domains in Brd2 binding to chromatin.
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Affiliation(s)
- Jarmila Hnilicová
- Department of RNA Biology, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague 142 20, Czech Republic Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague 142 20, Czech Republic Max Planck Institute for Molecular Cell Biology and Genetics, Dresden 01307, Germany J. Heyrovsky Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Prague 182 23, Czech Republic
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Berkovits BD, Wolgemuth DJ. The role of the double bromodomain-containing BET genes during mammalian spermatogenesis. Curr Top Dev Biol 2013; 102:293-326. [PMID: 23287038 DOI: 10.1016/b978-0-12-416024-8.00011-8] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The double bromodomain-containing BET (bromodomain and extra terminal) family of proteins is highly conserved from yeast to humans and consists not just of transcriptional regulators but also histone-interacting chromatin remodelers. The four mammalian BET genes are each expressed at unique times during spermatogenesis, and the testis-specific gene Brdt is essential for spermatogenesis. Loss of the first bromodomain of BRDT results in improper/incomplete spermatid elongation and severely morphologically defective sperm. The elongation defects observed in mutant spermatids can be directly tied to altered postmeiotic chromatin architecture. BRDT is required for creation/maintenance of the chromocenter of round spermatids, a structure that forms just after completion of meiosis. The chromocenter creates a defined topology in spermatids, and the presence of multiple chromocenters rather than a single intact chromocenter correlates with loss of spermatid polarity, loss of heterochromatin foci at the nuclear envelope, and loss of proper spermatid elongation. BRDT is not only essential for proper chromatin organization but also involved in regulation of transcription and in cotranscriptional processing. That is, transcription and alternative splicing are altered in spermatocytes and spermatids that lack full-length BRDT. Additionally, the transcription of mRNAs with short 3' UTRs, which is characteristic of round spermatids, is also altered. Examination of the genes regulated by BRDT yields many possible targets that could in part explain the morphologically abnormal sperm produced by the BRDT mutant testes. Thus, BRDT and possibly the other BET genes are required for proper spermatogenesis, which opens up the possibility that the recently discovered small molecule inhibitors of the BET family could be useful as reversible male contraceptives.
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Affiliation(s)
- Binyamin D Berkovits
- Department of Genetics and Development, Columbia University Medical Center, New York, USA
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35
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A combination of H2A.Z and H4 acetylation recruits Brd2 to chromatin during transcriptional activation. PLoS Genet 2012; 8:e1003047. [PMID: 23144632 PMCID: PMC3493454 DOI: 10.1371/journal.pgen.1003047] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2012] [Accepted: 09/11/2012] [Indexed: 11/19/2022] Open
Abstract
H2A.Z is an essential histone variant that has been implicated to have multiple chromosomal functions. To understand how H2A.Z participates in such diverse activities, we sought to identify downstream effector proteins that are recruited to chromatin via H2A.Z. For this purpose, we developed a nucleosome purification method to isolate H2A.Z-containing nucleosomes from human cells and used mass spectrometry to identify the co-purified nuclear proteins. Through stringent filtering, we identified the top 21 candidates, many of which have conserved structural motifs that bind post-translationally modified histones. We further validated the biological significance of one such candidate, Brd2, which is a double-bromodomain-containing protein known to function in transcriptional activation. We found that Brd2's preference for H2A.Z nucleosomes is mediated through a combination of hyperacetylated H4 on these nucleosomes, as well as additional features on H2A.Z itself. In addition, comparison of nucleosomes containing either H2A.Z-1 or H2A.Z-2 isoforms showed that significantly more Brd2 co-purifies with the former, suggesting these two isoforms engage different downstream effector proteins. Consistent with these biochemical analyses, we found that Brd2 is recruited to AR–regulated genes in an H2A.Z-dependent manner and that chemical inhibition of Brd2 recruitment greatly inhibits AR–regulated gene expression. Taken together, we propose that Brd2 is a key downstream mediator that links H2A.Z and transcriptional activation of AR–regulated genes. Moreover, this study validates the approach of using proteomics to identify nucleosome-interacting proteins in order to elucidate downstream mechanistic functions associated with the histone variant H2A.Z. Within the cell's nucleus, DNA closely associates with histone proteins, forming a structure known as chromatin. Packaging DNA into chromatin allows for efficient storage of the genome, and it also provides an additional means of regulating processes, such as gene expression, that require access to DNA. Two copies each of the four core histones (H2A, H2B, H3, H4) associate with approximately 150 base pairs of DNA to make up the basic unit of chromatin, the nucleosome. In addition to the core histones, variants exist that have specialized functions within chromatin. One such variant is H2A.Z, which is essential for cell viability. Here, we describe an approach by which to characterize proteins that interact with H2A.Z-containing nucleosomes. Our findings reveal that many of the identified proteins may interact with H2A.Z nucleosomes by recognizing specific chemical modifications uniquely present on H2A.Z nucleosomes. One such protein, Brd2, interacted in a manner dependent on recognition of acetylated histone residues that are enriched on H2A.Z nucleosomes. Furthermore, this interaction is required for expression of hormone-responsive genes in prostate cancer cells. By this approach, we uncovered a key mediator linking H2A.Z to transcriptional regulation and found a potentially targetable step to regulate prostate cell proliferation.
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Berkovits BD, Wang L, Guarnieri P, Wolgemuth DJ. The testis-specific double bromodomain-containing protein BRDT forms a complex with multiple spliceosome components and is required for mRNA splicing and 3'-UTR truncation in round spermatids. Nucleic Acids Res 2012; 40:7162-75. [PMID: 22570411 PMCID: PMC3424537 DOI: 10.1093/nar/gks342] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Revised: 04/05/2012] [Accepted: 04/10/2012] [Indexed: 12/02/2022] Open
Abstract
Members of the BET (bromodomain and extra terminal motif) family of proteins have been shown to be chromatin-interacting regulators of transcription. We previously generated a mutation in the testis-specific mammalian BET gene Brdt (bromodomain, testis-specific) that yields protein lacking the first bromodomain (BRDT(ΔBD1)) and observed disrupted spermiogenesis and male sterility. To determine whether BRDT(ΔBD1) protein results in altered transcription, we analyzed the transcriptomes of control versus Brdt(ΔBD1/ΔBD1) round spermatids. Over 400 genes showed statistically significant differential expression, and among the up-regulated genes, there was an enrichment of RNA splicing genes. Over 60% of these splicing genes had transcripts that lacked truncation of their 3'-untranslated region (UTR) typical of round spermatids. We selected four of these genes to characterize: Srsf2, Ddx5, Hnrnpk and Tardbp. The 3'-UTRs of Srsf2, Ddx5 and Hnrnpk mRNAs were longer in mutant round spermatids and resulted in reduced protein levels. Tardbp was transcriptionally up-regulated and a splicing shift toward the longer variant was observed. All four splicing proteins were found to complex with BRDT in control and mutant testes. We thus suggest that, along with modulating transcription, BRDT modulates gene expression as part of the splicing machinery. These modulations alter 3'-UTR processing in round spermatids; importantly, the BD1 is essential for these functions.
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Affiliation(s)
- Binyamin D. Berkovits
- Department of Genetics and Development, Biomedical Informatics Shared Resources, Bioinformatics Division, The Herbert Irving Comprehensive Cancer Center, The Institute of Human Nutrition and Department of Obstetrics and Gynecology, Columbia University Medical Center, New York, NY 10032, USA
| | - Li Wang
- Department of Genetics and Development, Biomedical Informatics Shared Resources, Bioinformatics Division, The Herbert Irving Comprehensive Cancer Center, The Institute of Human Nutrition and Department of Obstetrics and Gynecology, Columbia University Medical Center, New York, NY 10032, USA
| | - Paolo Guarnieri
- Department of Genetics and Development, Biomedical Informatics Shared Resources, Bioinformatics Division, The Herbert Irving Comprehensive Cancer Center, The Institute of Human Nutrition and Department of Obstetrics and Gynecology, Columbia University Medical Center, New York, NY 10032, USA
| | - Debra J. Wolgemuth
- Department of Genetics and Development, Biomedical Informatics Shared Resources, Bioinformatics Division, The Herbert Irving Comprehensive Cancer Center, The Institute of Human Nutrition and Department of Obstetrics and Gynecology, Columbia University Medical Center, New York, NY 10032, USA
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Abstract
The bromodomain is a highly conserved motif of 110 amino acids that is bundled into four anti-parallel α-helices and found in proteins that interact with chromatin, such as transcription factors, histone acetylases and nucleosome remodelling complexes. Bromodomain proteins are chromatin 'readers'; they recruit chromatin-regulating enzymes, including 'writers' and 'erasers' of histone modification, to target promoters and to regulate gene expression. Conventional wisdom held that complexes involved in chromatin dynamics are not 'druggable' targets. However, small molecules that inhibit bromodomain and extraterminal (BET) proteins have been described. We examine these developments and discuss the implications for small molecule epigenetic targeting of chromatin networks in cancer.
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Affiliation(s)
- Anna C Belkina
- Cancer Research Center, Nutrition Obesity Research Center, Departments of Medicine and Pharmacology, Boston University School of Medicine, 72 East Concord Street, Boston, MA 02118, USA
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Josling GA, Selvarajah SA, Petter M, Duffy MF. The role of bromodomain proteins in regulating gene expression. Genes (Basel) 2012; 3:320-43. [PMID: 24704920 PMCID: PMC3899951 DOI: 10.3390/genes3020320] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 05/11/2012] [Accepted: 05/17/2012] [Indexed: 11/25/2022] Open
Abstract
Histone modifications are important in regulating gene expression in eukaryotes. Of the numerous histone modifications which have been identified, acetylation is one of the best characterised and is generally associated with active genes. Histone acetylation can directly affect chromatin structure by neutralising charges on the histone tail, and can also function as a binding site for proteins which can directly or indirectly regulate transcription. Bromodomains specifically bind to acetylated lysine residues on histone tails, and bromodomain proteins play an important role in anchoring the complexes of which they are a part to acetylated chromatin. Bromodomain proteins are involved in a diverse range of functions, such as acetylating histones, remodeling chromatin, and recruiting other factors necessary for transcription. These proteins thus play a critical role in the regulation of transcription.
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Affiliation(s)
- Gabrielle A Josling
- Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Australia.
| | - Shamista A Selvarajah
- Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Australia.
| | - Michaela Petter
- Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Australia.
| | - Michael F Duffy
- Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Australia.
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Boehm D, Calvanese V, Dar RD, Xing S, Schroeder S, Martins L, Aull K, Li PC, Planelles V, Bradner JE, Zhou MM, Siliciano RF, Weinberger L, Verdin E, Ott M. BET bromodomain-targeting compounds reactivate HIV from latency via a Tat-independent mechanism. Cell Cycle 2012; 12:452-62. [PMID: 23255218 DOI: 10.4161/cc.23309] [Citation(s) in RCA: 179] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The therapeutic potential of pharmacologic inhibition of bromodomain and extraterminal (BET) proteins has recently emerged in hematological malignancies and chronic inflammation. We find that BET inhibitor compounds (JQ1, I-Bet, I-Bet151 and MS417) reactivate HIV from latency. This is evident in polyclonal Jurkat cell populations containing latent infectious HIV, as well as in a primary T-cell model of HIV latency. Importantly, we show that this activation is dependent on the positive transcription elongation factor p-TEFb but independent from the viral Tat protein, arguing against the possibility that removal of the BET protein BRD4, which functions as a cellular competitor for Tat, serves as a primary mechanism for BET inhibitor action. Instead, we find that the related BET protein, BRD2, enforces HIV latency in the absence of Tat, pointing to a new target for BET inhibitor treatment in HIV infection. In shRNA-mediated knockdown experiments, knockdown of BRD2 activates HIV transcription to the same extent as JQ1 treatment, while a lesser effect is observed with BRD4. In single-cell time-lapse fluorescence microscopy, quantitative analyses across ~2,000 viral integration sites confirm the Tat-independent effect of JQ1 and point to positive effects of JQ1 on transcription elongation, while delaying re-initiation of the polymerase complex at the viral promoter. Collectively, our results identify BRD2 as a new Tat-independent suppressor of HIV transcription in latently infected cells and underscore the therapeutic potential of BET inhibitors in the reversal of HIV latency.
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Affiliation(s)
- Daniela Boehm
- Gladstone Institute of Virology and Immunology, San Francisco, CA, USA
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Wegner N, Lundberg K, Kinloch A, Fisher B, Malmström V, Feldmann M, Venables PJ. Autoimmunity to specific citrullinated proteins gives the first clues to the etiology of rheumatoid arthritis. Immunol Rev 2010; 233:34-54. [PMID: 20192991 DOI: 10.1111/j.0105-2896.2009.00850.x] [Citation(s) in RCA: 352] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Rheumatoid arthritis (RA) is now clearly a true autoimmune disease with accumulating evidence of pathogenic disease-specific autoimmunity to citrullinated proteins. Citrullination, also termed deimination, is a modification of arginine side chains catalyzed by peptidylarginine deiminase (PAD) enzymes. This post-translational modification has the potential to alter the structure, antigenicity, and function of proteins. In RA, antibodies to cyclic citrullinated peptides are now well established for clinical diagnosis, though we argue that the identification of specific citrullinated antigens, as whole proteins, is necessary for exploring pathogenic mechanisms. Four citrullinated antigens, fibrinogen, vimentin, collagen type II, and alpha-enolase, are now well established, with others awaiting further characterization. All four proteins are expressed in the joint, and there is evidence that antibodies to citrullinated fibrinogen and collagen type II mediate inflammation by the formation of immune complexes, both in humans and animal models. Antibodies to citrullinated proteins are associated with HLA 'shared epitope' alleles, and autoimmunity to at least one antigenic sequence, the CEP-1 peptide from citrullinated alpha-enolase (KIHAcitEIFDScitGNPTVE), shows a specific association with HLA-DRB1*0401, *0404, 620W PTPN22, and smoking. Periodontitis, in which Porphyromonas gingivalis is a major pathogenic bacterium, has been linked to RA in epidemiological studies and also shares similar gene/environment associations. This is also the only bacterium identified that expresses endogenous citrullinated proteins and its own bacterial PAD enzyme, though the precise molecular mechanisms of bacterial citrullination have yet to be explored. Thus, both smoking and Porphyromonas gingivalis are attractive etiological agents for further investigation into the gene/environment/autoimmunity triad of RA.
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Affiliation(s)
- Natalia Wegner
- The Kennedy Institute of Rheumatology, Imperial College London, London, UK
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Mahdi H, Fisher BA, Källberg H, Plant D, Malmström V, Rönnelid J, Charles P, Ding B, Alfredsson L, Padyukov L, Symmons DPM, Venables PJ, Klareskog L, Lundberg K. Specific interaction between genotype, smoking and autoimmunity to citrullinated alpha-enolase in the etiology of rheumatoid arthritis. Nat Genet 2009; 41:1319-24. [PMID: 19898480 DOI: 10.1038/ng.480] [Citation(s) in RCA: 230] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2009] [Accepted: 10/01/2009] [Indexed: 12/27/2022]
Abstract
Gene-environment associations are important in rheumatoid arthritis (RA) susceptibility, with an association existing between smoking, HLA- DRB1 'shared epitope' alleles, PTPN22 and antibodies to cyclic citrullinated peptides (CCP). Here, we test the hypothesis that a subset of the anti-CCP response, with specific autoimmunity to citrullinated alpha-enolase, accounts for an important portion of these associations. In 1,497 individuals from three RA cohorts, antibodies to the immunodominant citrullinated alpha-enolase CEP-1 epitope were detected in 43-63% of the anti-CCP-positive individuals, and this subset was preferentially linked to HLA-DRB1*04. In a case-control analysis of 1,000 affected individuals and 872 controls, the combined effect of shared epitope, PTPN22 and smoking showed the strongest association with the anti-CEP-1-positive subset (odds ratio (OR) of 37, compared to an OR of 2 for the corresponding anti-CEP-1-negative, anti-CCP-positive subset). We conclude that citrullinated alpha-enolase is a specific citrullinated autoantigen that links smoking to genetic risk factors in the development of RA.
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Affiliation(s)
- Hiba Mahdi
- Rheumatology Unit, Karolinska Institutet, Center for Molecular Medicine, Stockholm, Sweden
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Huang H, Zhang J, Shen W, Wang X, Wu J, Wu J, Shi Y. Solution structure of the second bromodomain of Brd2 and its specific interaction with acetylated histone tails. BMC STRUCTURAL BIOLOGY 2007; 7:57. [PMID: 17848202 PMCID: PMC2065866 DOI: 10.1186/1472-6807-7-57] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2007] [Accepted: 09/12/2007] [Indexed: 11/26/2022]
Abstract
Background Brd2 is a transcriptional regulator and belongs to BET family, a less characterized novel class of bromodomain-containing proteins. Brd2 contains two tandem bromodomains (BD1 and BD2, 46% sequence identity) in the N-terminus and a conserved motif named ET (extra C-terminal) domain at the C-terminus that is also present in some other bromodomain proteins. The two bromodomains have been shown to bind the acetylated histone H4 and to be responsible for mitotic retention on chromosomes, which is probably a distinctive feature of BET family proteins. Although the crystal structure of Brd2 BD1 is reported, no structure features have been characterized for Brd2 BD2 and its interaction with acetylated histones. Results Here we report the solution structure of human Brd2 BD2 determined by NMR. Although the overall fold resembles the bromodomains from other proteins, significant differences can be found in loop regions, especially in the ZA loop in which a two amino acids insertion is involved in an uncommon π-helix, termed πD. The helix πD forms a portion of the acetyl-lysine binding site, which could be a structural characteristic of Brd2 BD2 and other BET bromodomains. Unlike Brd2 BD1, BD2 is monomeric in solution. With NMR perturbation studies, we have mapped the H4-AcK12 peptide binding interface on Brd2 BD2 and shown that the binding was with low affinity (2.9 mM) and in fast exchange. Using NMR and mutational analysis, we identified several residues important for the Brd2 BD2-H4-AcK12 peptide interaction and probed the potential mechanism for the specific recognition of acetylated histone codes by Brd2 BD2. Conclusion Brd2 BD2 is monomeric in solution and dynamically interacts with H4-AcK12. The additional secondary elements in the long ZA loop may be a common characteristic of BET bromodomains. Surrounding the ligand-binding cavity, five aspartate residues form a negatively charged collar that serves as a secondary binding site for H4-AcK12. We suggest that Brd2 BD1 and BD2 may possess distinctive roles and cooperate to regulate Brd2 functions. The structure basis of Brd2 BD2 will help to further characterize the functions of Brd2 and its BET members.
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Affiliation(s)
- Hongda Huang
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Science, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Jiahai Zhang
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Science, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Weiqun Shen
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Science, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Xingsheng Wang
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Science, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Jiawen Wu
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Science, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Jihui Wu
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Science, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
| | - Yunyu Shi
- Hefei National Laboratory for Physical Sciences at Microscale and School of Life Science, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China
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