1
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Wahi A, Manchanda N, Jain P, Jadhav HR. Targeting the epigenetic reader "BET" as a therapeutic strategy for cancer. Bioorg Chem 2023; 140:106833. [PMID: 37683545 DOI: 10.1016/j.bioorg.2023.106833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 08/22/2023] [Accepted: 08/30/2023] [Indexed: 09/10/2023]
Abstract
Bromodomain and extraterminal (BET) proteins have the ability to bind to acetylated lysine residues present in both histones and non-histone proteins. This binding is facilitated by the presence of tandem bromodomains. The regulatory role of BET proteins extends to chromatin dynamics, cellular processes, and disease progression. The BET family comprises of BRD 2, 3, 4 and BRDT. The BET proteins are a class of epigenetic readers that regulate the transcriptional activity of a multitude of genes that are involved in the pathogenesis of cancer. Thus, targeting BET proteins has been identified as a potentially efficacious approach for the treatment of cancer. BET inhibitors (BETis) are known to interfere with the binding of BET proteins to acetylated lysine residues of chromatin, thereby leading to the suppression of transcription of several genes, including oncogenic transcription factors. Here in this review, we focus on role of Bromodomain and extra C-terminal (BET) proteins in cancer progression. Furthermore, numerous small-molecule inhibitors with pan-BET activity have been documented, with certain compounds currently undergoing clinical assessment. However, it is apparent that the clinical effectiveness of the present BET inhibitors is restricted, prompting the exploration of novel technologies to enhance their clinical outcomes and mitigate undesired adverse effects. Thus, strategies like development of selective BET-BD1, & BD2 inhibitors, dual and acting BET are also presented in this review and attempts to cover the chemistry needed for proper establishment of designed molecules into BRD have been made. Moreover, the review attempts to summarize the details of research till date and proposes a space for future development of BET inhibitor with diminished side effects. It can be concluded that discovery of isoform selective BET inhibitors can be a way forward in order to develop BET inhibitors with negligible side effects.
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Affiliation(s)
- Abhishek Wahi
- Department of Pharmaceutical Chemistry, School of Pharmaceutical Sciences, Delhi Pharmaceutical Sciences and Research University, Govt. of NCT of Delhi, Delhi, New Delhi 110017, India
| | - Namish Manchanda
- Department of Pharmaceutical Chemistry, School of Pharmaceutical Sciences, Delhi Pharmaceutical Sciences and Research University, Govt. of NCT of Delhi, Delhi, New Delhi 110017, India
| | - Priti Jain
- Department of Pharmaceutical Chemistry, School of Pharmaceutical Sciences, Delhi Pharmaceutical Sciences and Research University, Govt. of NCT of Delhi, Delhi, New Delhi 110017, India.
| | - Hemant R Jadhav
- Department of Pharmacy, Birla Institute of Technology and Science, Pilani-Pilani Campus, Vidya Vihar Pilani, Rajasthan 333031, India
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2
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Bardani E, Kallemi P, Tselika M, Katsarou K, Kalantidis K. Spotlight on Plant Bromodomain Proteins. BIOLOGY 2023; 12:1076. [PMID: 37626962 PMCID: PMC10451976 DOI: 10.3390/biology12081076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 07/28/2023] [Accepted: 07/30/2023] [Indexed: 08/27/2023]
Abstract
Bromodomain-containing proteins (BRD-proteins) are the "readers" of histone lysine acetylation, translating chromatin state into gene expression. They act alone or as components of larger complexes and exhibit diverse functions to regulate gene expression; they participate in chromatin remodeling complexes, mediate histone modifications, serve as scaffolds to recruit transcriptional regulators or act themselves as transcriptional co-activators or repressors. Human BRD-proteins have been extensively studied and have gained interest as potential drug targets for various diseases, whereas in plants, this group of proteins is still not well investigated. In this review, we aimed to concentrate scientific knowledge on these chromatin "readers" with a focus on Arabidopsis. We organized plant BRD-proteins into groups based on their functions and domain architecture and summarized the published work regarding their interactions, activity and diverse functions. Overall, it seems that plant BRD-proteins are indispensable components and fine-tuners of the complex network plants have built to regulate development, flowering, hormone signaling and response to various biotic or abiotic stresses. This work will facilitate the understanding of their roles in plants and highlight BRD-proteins with yet undiscovered functions.
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Affiliation(s)
- Eirini Bardani
- Department of Biology, University of Crete, Voutes University Campus, 71500 Heraklion, Greece; (E.B.); (P.K.); (M.T.)
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013 Heraklion, Greece
| | - Paraskevi Kallemi
- Department of Biology, University of Crete, Voutes University Campus, 71500 Heraklion, Greece; (E.B.); (P.K.); (M.T.)
| | - Martha Tselika
- Department of Biology, University of Crete, Voutes University Campus, 71500 Heraklion, Greece; (E.B.); (P.K.); (M.T.)
| | - Konstantina Katsarou
- Department of Biology, University of Crete, Voutes University Campus, 71500 Heraklion, Greece; (E.B.); (P.K.); (M.T.)
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013 Heraklion, Greece
| | - Kriton Kalantidis
- Department of Biology, University of Crete, Voutes University Campus, 71500 Heraklion, Greece; (E.B.); (P.K.); (M.T.)
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, 70013 Heraklion, Greece
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3
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Chen IP, Ott M. Viral Hijacking of BET Proteins. Viruses 2022; 14:v14102274. [PMID: 36298829 PMCID: PMC9609653 DOI: 10.3390/v14102274] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 10/09/2022] [Accepted: 10/11/2022] [Indexed: 11/29/2022] Open
Abstract
Proteins of the bromodomain and exterminal domain (BET) family mediate critical host functions such as cell proliferation, transcriptional regulation, and the innate immune response, which makes them preferred targets for viruses. These multidomain proteins are best known as transcriptional effectors able to read acetylated histone and non-histone proteins through their tandem bromodomains. They also contain other short motif-binding domains such as the extraterminal domain, which recognizes transcriptional regulatory proteins. Here, we describe how different viruses have evolved to hijack or disrupt host BET protein function through direct interactions with BET family members to support their own propagation. The network of virus-BET interactions emerges as highly intricate, which may complicate the use of small-molecule BET inhibitors-currently in clinical development for the treatment of cancer and cardiovascular diseases-to treat viral infections.
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Affiliation(s)
- Irene P. Chen
- Gladstone Institutes, San Francisco, CA 94158, USA
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Melanie Ott
- Gladstone Institutes, San Francisco, CA 94158, USA
- Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA
- Chan Zuckerberg Biohub, San Francisco, CA 94158, USA
- Correspondence:
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4
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Kong P, Zhang L, Zhang Z, Feng K, Sang Y, Duan X, Liu C, Sun T, Tao Z, Liu W. Emerging Proteins in CRPC: Functional Roles and Clinical Implications. Front Oncol 2022; 12:873876. [PMID: 35756667 PMCID: PMC9226405 DOI: 10.3389/fonc.2022.873876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Accepted: 03/30/2022] [Indexed: 11/13/2022] Open
Abstract
Prostate cancer (PCa) is the most common cancer in men in the western world, but the lack of specific and sensitive markers often leads to overtreatment of prostate cancer which eventually develops into castration-resistant prostate cancer (CRPC). Novel protein markers for diagnosis and management of CRPC will be promising. In this review, we systematically summarize and discuss the expression pattern of emerging proteins in tissue, cell lines, and serum when castration-sensitive prostate cancer (CSPC) progresses to CRPC; focus on the proteins involved in CRPC growth, invasion, metastasis, metabolism, and immune microenvironment; summarize the current understanding of the regulatory mechanisms of emerging proteins in CSPC progressed to CRPC at the molecular level; and finally summarize the clinical applications of emerging proteins as diagnostic marker, prognostic marker, predictive marker, and therapeutic marker.
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Affiliation(s)
- Piaoping Kong
- Department of Laboratory Medicine, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Lingyu Zhang
- Department of Laboratory Medicine, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Zhengliang Zhang
- Department of Laboratory Medicine, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Kangle Feng
- Department of Laboratory Medicine, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Yiwen Sang
- Department of Laboratory Medicine, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Xiuzhi Duan
- Department of Laboratory Medicine, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Chunhua Liu
- Department of Blood Transfusion, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Tao Sun
- Department of Laboratory Medicine, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Zhihua Tao
- Department of Laboratory Medicine, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Weiwei Liu
- Department of Laboratory Medicine, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, China
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5
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Ali HA, Li Y, Bilal AHM, Qin T, Yuan Z, Zhao W. A Comprehensive Review of BET Protein Biochemistry, Physiology, and Pathological Roles. Front Pharmacol 2022; 13:818891. [PMID: 35401196 PMCID: PMC8990909 DOI: 10.3389/fphar.2022.818891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 01/26/2022] [Indexed: 11/13/2022] Open
Abstract
Epigenetic modifications, specifically acetylation of histone plays a decisive role in gene regulation and transcription of normal cellular mechanisms and pathological conditions. The bromodomain and extraterminal (BET) proteins (BRD2, BRD3, BRD4, and BRDT), being epigenetic readers, ligate to acetylated regions of histone and synchronize gene transcription. BET proteins are crucial for normal cellular processing as they control cell cycle progression, neurogenesis, differentiation, and maturation of erythroids and spermatogenesis, etc. Research-based evidence indicated that BET proteins (mainly BRD4) are associated with numeral pathological ailments, including cancer, inflammation, infections, renal diseases, and cardiac diseases. To counter the BET protein-related pathological conditions, there are some BET inhibitors developed and also under development. BET proteins are a topic of most research nowadays. This review, provides an ephemeral but comprehensive knowledge about BET proteins’ basic structure, biochemistry, physiological roles, and pathological conditions in which the role of BETs have been proven. This review also highlights the current and future approaches to pledge BET protein-related pathologies.
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Affiliation(s)
- Hafiz Akbar Ali
- Affiliated Cancer Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China.,Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education, School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
| | - Yalan Li
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education, School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
| | - Akram Hafiz Muhammad Bilal
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education, School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
| | - Tingting Qin
- Affiliated Cancer Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, China
| | - Ziqiao Yuan
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education, School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China
| | - Wen Zhao
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education, School of Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, China.,State Key Laboratory of Esophageal Cancer Prevention and Treatment, Zhengzhou University, Zhengzhou, China
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6
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Donczew R, Hahn S. BET family members Bdf1/2 modulate global transcription initiation and elongation in Saccharomyces cerevisiae. eLife 2021; 10:e69619. [PMID: 34137374 PMCID: PMC8266393 DOI: 10.7554/elife.69619] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 06/16/2021] [Indexed: 01/10/2023] Open
Abstract
Human bromodomain and extra-terminal domain (BET) family members are promising targets for therapy of cancer and immunoinflammatory diseases, but their mechanisms of action and functional redundancies are poorly understood. Bdf1/2, yeast homologues of the human BET factors, were previously proposed to target transcription factor TFIID to acetylated histone H4, analogous to bromodomains that are present within the largest subunit of metazoan TFIID. We investigated the genome-wide roles of Bdf1/2 and found that their important contributions to transcription extend beyond TFIID function as transcription of many genes is more sensitive to Bdf1/2 than to TFIID depletion. Bdf1/2 co-occupy the majority of yeast promoters and affect preinitiation complex formation through recruitment of TFIID, Mediator, and basal transcription factors to chromatin. Surprisingly, we discovered that hypersensitivity of genes to Bdf1/2 depletion results from combined defects in transcription initiation and early elongation, a striking functional similarity to human BET proteins, most notably Brd4. Our results establish Bdf1/2 as critical for yeast transcription and provide important mechanistic insights into the function of BET proteins in all eukaryotes.
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Affiliation(s)
- Rafal Donczew
- Fred Hutchinson Cancer Research Center, Division of Basic SciencesSeattleUnited States
| | - Steven Hahn
- Fred Hutchinson Cancer Research Center, Division of Basic SciencesSeattleUnited States
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7
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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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8
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Proteolysis-targeting chimeras mediate the degradation of bromodomain and extra-terminal domain proteins. Future Med Chem 2020; 12:1669-1683. [PMID: 32893690 DOI: 10.4155/fmc-2017-0264] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Bromodomain and extra-terminal domain (BET) protein family plays an important role in regulating gene transcription preferentially at super-enhancer regions and has been involved with several types of cancers as a candidate. Up to now, there are 16 pan-BET inhibitors in clinical trials, however, most of them have undesirable off-target and side-effects. The proteolysis-targeting chimeras technology through a heterobifunctional molecule to link the target protein and E3 ubiquitin ligase, causes the target's ubiquitination and subsequent degradation. By using this technology, the heterobifunctional small-molecule BET degraders can induce BET protein degradation. In this review, we discuss the advances in the drug discovery and development of BET-targeting proteolysis-targeting chimeras.
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9
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Andrikopoulou A, Liontos M, Koutsoukos K, Dimopoulos MA, Zagouri F. The emerging role of BET inhibitors in breast cancer. Breast 2020; 53:152-163. [PMID: 32827765 PMCID: PMC7451423 DOI: 10.1016/j.breast.2020.08.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 07/13/2020] [Accepted: 08/10/2020] [Indexed: 01/10/2023] Open
Abstract
Bromodomain and extraterminal domain (BET) proteins are epigenetic molecules that regulate the expression of multiple genes involved in carcinogenesis. Breast cancer is an heterogenous disease emerging from aberrant gene expression and epigenetic alteration patterns. Amplification or overexpression of BET proteins has been identified in breast tumors highlighting their clinical significance. Development of BET inhibitors that disrupt BET protein binding to acetylated lysine residues of chromatin and suppress transcription of various oncogenes has shown promising results in breast cancer cells and xenograft models. Currently, Phase I/II clinical trials explore safety and efficacy of BET inhibitors in solid tumors and breast cancer. Treatment-emergent toxicities have been reported, including thrombocytopenia and gastrointestinal disorders. Preliminary results demonstrated greater response rates to BET inhibitors in combination with already approved anticancer agents. Consistently, BET inhibition sensitized breast tumors to chemotherapy drugs, hormone therapy and PI3K inhibitors in vitro. This article aims to review all existing preclinical and clinical evidence regarding BET inhibitors in breast cancer.
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Affiliation(s)
- Angeliki Andrikopoulou
- Oncology Unit, Department of Clinical Therapeutics, Alexandra Hospital, National and Kapodistrian University of Athens School of Medicine, Athens, Greece.
| | - Michalis Liontos
- Oncology Unit, Department of Clinical Therapeutics, Alexandra Hospital, National and Kapodistrian University of Athens School of Medicine, Athens, Greece.
| | - Konstantinos Koutsoukos
- Oncology Unit, Department of Clinical Therapeutics, Alexandra Hospital, National and Kapodistrian University of Athens School of Medicine, Athens, Greece.
| | - Meletios-Athanasios Dimopoulos
- Oncology Unit, Department of Clinical Therapeutics, Alexandra Hospital, National and Kapodistrian University of Athens School of Medicine, Athens, Greece.
| | - Flora Zagouri
- Oncology Unit, Department of Clinical Therapeutics, Alexandra Hospital, National and Kapodistrian University of Athens School of Medicine, Athens, Greece.
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10
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Luo F, Zhou Z, Cai J, Du W. DUB3 Facilitates Growth and Inhibits Apoptosis Through Enhancing Expression of EZH2 in Oral Squamous Cell Carcinoma. Onco Targets Ther 2020; 13:1447-1460. [PMID: 32110043 PMCID: PMC7035907 DOI: 10.2147/ott.s230577] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 01/15/2020] [Indexed: 12/23/2022] Open
Abstract
Background Here, we probed the action mechanism of ubiquitin-specific processing proteases 17 (DUB3) in the evolution of oral squamous cell carcinoma (OSCC). Methods The expression of genes were calculated by qRT-PCR, and proteins were assessed by Western blot and immunohistochemistry. The cells viability and proliferation were checked by MTT and EdU assay, respectively. Flow cytometry was implemented to detect the cell cycle and apoptosis. The activity of EZH2 gene promoter was measured by luciferase reporter assay. Co-immunoprecipitation assay was used to ensure the ubiquitination of bromodomain-containing protein 4 (BRD4). The cell apoptosis of tumor tissues was assessed by TUNEL assay. Results DUB3 was overexpressed in OSCC tissues and cell lines, and negatively correlated with patient’s survival time. DUB3 downregulation could effectively curb OSCC cells viability and proliferation, promote cell apoptosis and the expression of cleaved-caspase-3, cleaved PARP and p21, while inhibit cyclin D1. Besides, DUB3 production was positivity correlated with enhancer of zeste homolog-2 (EZH2) and BRD4. BRD4 downregulation could repress DUB3-induced EZH2 production, and MG132 reversed DUB3 decreasing-mediated BRD4 downregulation. Downregulation of DUB3 promoted BRD4 ubiquitination. DUB3 promoted OSCC cells proliferation, while suppressing apoptosis via facilitating EZH2 production. At last, in vivo experiment indicated that the downregulation of DUB3 significantly inhibited the growth of xenograft tumor. Conclusion In summary, we found that DUB3 enhanced OSCC cells proliferation and xenograft tumor growth, while inhibited their apoptosis via promoting BRD4-mediated upregulation of EZH2. Our study indicated that DUB3 may be an effective anti-cancer target for OSCC therapy.
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Affiliation(s)
- Fei Luo
- Department of Oncology, First People's Hospital of Jinzhou, Jinzhou 434000, People's Republic of China
| | - Zunyan Zhou
- Department of Oncology, First People's Hospital of Jinzhou, Jinzhou 434000, People's Republic of China
| | - Jun Cai
- Department of Oncology, First People's Hospital of Jinzhou, Jinzhou 434000, People's Republic of China
| | - Wei Du
- Department of Oncology, First People's Hospital of Jinzhou, Jinzhou 434000, People's Republic of China
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11
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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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12
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Letson C, Padron E. Non-canonical transcriptional consequences of BET inhibition in cancer. Pharmacol Res 2019; 150:104508. [PMID: 31698067 DOI: 10.1016/j.phrs.2019.104508] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 09/12/2019] [Accepted: 10/21/2019] [Indexed: 01/01/2023]
Abstract
Inhibition of the bromo and extra-terminal domain (BET) protein family in preclinical studies has demonstrated that BET proteins are critical for cancer progression and important therapeutic targets. Downregulation of the MYC oncogene, CDK6, BCL2 and FOSL1 are just a few examples of the effects of BET inhibitors that can lead to cell cycle arrest and apoptosis in cancer cells. However, BET inhibitors have had little success in the clinic as a single agent, and there are an increasing number of reports of resistance to BET inhibition emerging after sustained treatment of cancer cells in vitro. Here we summarize the non-canonical consequences of BET inhibition in cancer, and discuss how these may both lead to resistance and inform rational combinations that could greatly enhance the clinical application of these inhibitors.
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Affiliation(s)
- Christopher Letson
- Moffitt Cancer Center: 12902 USF Magnolia Drive, Tampa, FL 33612, United States.
| | - Eric Padron
- Moffitt Cancer Center: 12902 USF Magnolia Drive, Tampa, FL 33612, United States.
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13
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Shafran JS, Andrieu GP, Györffy B, Denis GV. BRD4 Regulates Metastatic Potential of Castration-Resistant Prostate Cancer through AHNAK. Mol Cancer Res 2019; 17:1627-1638. [PMID: 31110158 PMCID: PMC6677600 DOI: 10.1158/1541-7786.mcr-18-1279] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 03/29/2019] [Accepted: 05/09/2019] [Indexed: 12/19/2022]
Abstract
The inevitable progression of advanced prostate cancer to castration resistance, and ultimately to lethal metastatic disease, depends on primary or acquired resistance to conventional androgen deprivation therapy (ADT) and accumulated resistance strategies to evade androgen receptor (AR) suppression. In prostate cancer cells, AR adaptations that arise in response to ADT are not singular, but diverse, and include gene amplification, mutation, and even complete loss of receptor expression. Collectively, each of these AR adaptations contributes to a complex, heterogeneous, ADT-resistant tumor. Here, we examined prostate cancer cell lines that model common castration-resistant prostate cancer (CRPC) subtypes, each with different AR composition, and focused on novel regulators of tumor progression, the Bromodomain and Extraterminal (BET) family of proteins. We found that BRD4 regulates cell migration across all models of CRPC, regardless of aggressiveness and AR status, whereas BRD2 and BRD3 only regulate migration and invasion in less aggressive models that retain AR expression or signaling. BRD4, a coregulator of gene transcription, controls migration and invasion through transcription of AHNAK, a large scaffolding protein linked to promotion of metastasis in a diverse set of cancers. Furthermore, treatment of CRPC cell lines with low doses of MZ1, a small-molecule, BRD4-selective degrader, inhibits metastatic potential. Overall, these results reveal a novel BRD4-AHNAK pathway that may be targetable to treat metastatic CRPC (mCRPC). IMPLICATIONS: BRD4 functions as the dominant regulator of CRPC cell migration and invasion through direct transcriptional regulation of AHNAK, which together offer a novel targetable pathway to treat metastatic CRPC.Visual Overview: http://mcr.aacrjournals.org/content/molcanres/17/8/1627/F1.large.jpg.
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MESH Headings
- Apoptosis
- Biomarkers, Tumor/genetics
- Biomarkers, Tumor/metabolism
- Cell Cycle Proteins/genetics
- Cell Cycle Proteins/metabolism
- Cell Movement
- Cell Proliferation
- Gene Expression Regulation, Neoplastic
- Humans
- Male
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Neoplasm Metastasis
- Neoplasm Proteins/genetics
- Neoplasm Proteins/metabolism
- Neoplasm Recurrence, Local/genetics
- Neoplasm Recurrence, Local/metabolism
- Neoplasm Recurrence, Local/pathology
- Prognosis
- Prostatic Neoplasms, Castration-Resistant/genetics
- Prostatic Neoplasms, Castration-Resistant/metabolism
- Prostatic Neoplasms, Castration-Resistant/pathology
- Receptors, Androgen/genetics
- Receptors, Androgen/metabolism
- Signal Transduction
- Survival Rate
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Tumor Cells, Cultured
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Affiliation(s)
- Jordan S Shafran
- Boston University-Boston Medical Center Cancer Center, Boston, Massachusetts
- Department of Molecular and Translational Medicine, Boston University School of Medicine, Boston, Massachusetts
| | - Guillaume P Andrieu
- Boston University-Boston Medical Center Cancer Center, Boston, Massachusetts
| | - Balázs Györffy
- MTA TTK Lendület Cancer Biomarker Research Group, Institute of Enzymology, Budapest, Hungary
- Second Department of Pediatrics, Semmelweis University, Budapest, Hungary
| | - Gerald V Denis
- Boston University-Boston Medical Center Cancer Center, Boston, Massachusetts.
- Department of Molecular and Translational Medicine, Boston University School of Medicine, Boston, Massachusetts
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, Massachusetts
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14
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Lee DJ, Hwang JH, Ha J, Yu GE, Kwon S, Park DH, Kang DG, Kim TW, Park HC, An SM, Kim CW. Identification of a Bromodomain-containing Protein 2 (BRD2) Gene Polymorphic Variant and Its Effects on Pork Quality Traits in Berkshire Pigs. Korean J Food Sci Anim Resour 2018; 38:703-710. [PMID: 30206429 PMCID: PMC6131382 DOI: 10.5851/kosfa.2018.e7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 06/08/2018] [Accepted: 06/14/2018] [Indexed: 01/21/2023] Open
Abstract
Bromodomain-containing protein 2 (BRD2) is a nuclear serine/threonine kinase involved in transcriptional regulation. We investigated the expression and association of the BRD2 gene as a candidate gene for meat quality traits in Berkshire pigs. BRD2 mRNA was expressed at relatively high levels in muscle tissue. Statistical analysis revealed that the c.1709G>C polymorphism of the BRD2 gene was significantly associated with carcass weight, meat color (a*, redness), protein content, cooking loss, water-holding capacity, carcass temperatures 4, 12 and 24 h postmortem, and the 24 h postmortem pH in 384 Berkshire pigs. Therefore, this polymorphism in the porcine BRD2 gene may be used as a candidate genetic marker to improve meat quality traits in pigs.
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Affiliation(s)
- Dong Ju Lee
- Department of Animal Resource Technology, Gyeongnam National University of Science & Technology, Jinju 52725, Korea
| | - Jung Hye Hwang
- Swine Science and Technology Center, Gyeongnam National University of Science & Technology, Jinju 52725, Korea
| | - Jeongim Ha
- Swine Science and Technology Center, Gyeongnam National University of Science & Technology, Jinju 52725, Korea
| | - Go Eun Yu
- Swine Science and Technology Center, Gyeongnam National University of Science & Technology, Jinju 52725, Korea
| | - Seulgi Kwon
- Swine Science and Technology Center, Gyeongnam National University of Science & Technology, Jinju 52725, Korea
| | - Da Hye Park
- Swine Science and Technology Center, Gyeongnam National University of Science & Technology, Jinju 52725, Korea
| | - Deok Gyeong Kang
- Swine Science and Technology Center, Gyeongnam National University of Science & Technology, Jinju 52725, Korea
| | - Tae Wan Kim
- Swine Science and Technology Center, Gyeongnam National University of Science & Technology, Jinju 52725, Korea
| | - Hwa Chun Park
- Swine Science and Technology Center, Gyeongnam National University of Science & Technology, Jinju 52725, Korea
| | - Sang Mi An
- Swine Science and Technology Center, Gyeongnam National University of Science & Technology, Jinju 52725, Korea
| | - Chul Wook Kim
- Department of Animal Resource Technology, Gyeongnam National University of Science & Technology, Jinju 52725, Korea.,Swine Science and Technology Center, Gyeongnam National University of Science & Technology, Jinju 52725, Korea
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15
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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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16
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Caumanns JJ, Wisman GBA, Berns K, van der Zee AGJ, de Jong S. ARID1A mutant ovarian clear cell carcinoma: A clear target for synthetic lethal strategies. Biochim Biophys Acta Rev Cancer 2018; 1870:176-184. [PMID: 30025943 DOI: 10.1016/j.bbcan.2018.07.005] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 07/12/2018] [Accepted: 07/13/2018] [Indexed: 12/20/2022]
Abstract
SWI/SNF chromatin remodeling complexes play an important role in the epigenetic regulation of chromatin structure and gene transcription. Mutual exclusive subunits in the SWI/SNF complex include the DNA targeting members ARID1A and ARID1B as well as the ATPases SMARCA2 and SMARCA4. SWI/SNF complexes are mutated across many cancer types. The highest mutation incidence is found in ARID1A, primarily consisting of deleterious mutations. Current advances have reported synthetic lethal interactions with the loss of ARID1A in several cancer types. In this review, we discuss targets that are only important for tumor growth in an ARID1A mutant context. We focus on synthetic lethal strategies with ARID1A loss in ovarian clear cell carcinoma, a cancer with the highest ARID1A mutation incidence (46-57%). ARID1A directed lethal strategies that can be exploited clinically include targeting of the DNA repair proteins PARP and ATR, and the epigenetic factors EZH2, HDAC2, HDAC6 and BRD2.
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Affiliation(s)
- Joseph J Caumanns
- Department of Gynecologic Oncology, University of Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands
| | - G Bea A Wisman
- Department of Gynecologic Oncology, University of Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands
| | - Katrien Berns
- Division of Molecular Carcinogenesis, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands
| | - Ate G J van der Zee
- Department of Gynecologic Oncology, University of Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands
| | - Steven de Jong
- Department of Medical Oncology, Cancer Research Centre Groningen, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands.
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17
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Berns K, Caumanns JJ, Hijmans EM, Gennissen AMC, Severson TM, Evers B, Wisman GBA, Jan Meersma G, Lieftink C, Beijersbergen RL, Itamochi H, van der Zee AGJ, de Jong S, Bernards R. ARID1A mutation sensitizes most ovarian clear cell carcinomas to BET inhibitors. Oncogene 2018; 37:4611-4625. [PMID: 29760405 PMCID: PMC6095834 DOI: 10.1038/s41388-018-0300-6] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 03/23/2018] [Accepted: 04/10/2018] [Indexed: 12/16/2022]
Abstract
Current treatment for advanced stage ovarian clear cell cancer is severely hampered by a lack of effective systemic therapy options, leading to a poor outlook for these patients. Sequencing studies revealed that ARID1A is mutated in over 50% of ovarian clear cell carcinomas. To search for a rational approach to target ovarian clear cell cancers with ARID1A mutations, we performed kinome-centered lethality screens in a large panel of ovarian clear cell carcinoma cell lines. Using the largest OCCC cell line panel established to date, we show here that BRD2 inhibition is predominantly lethal in ARID1A mutated ovarian clear cell cancer cells. Importantly, small molecule inhibitors of the BET (bromodomain and extra terminal domain) family of proteins, to which BRD2 belongs, specifically inhibit proliferation of ARID1A mutated cell lines, both in vitro and in ovarian clear cell cancer xenografts and patient-derived xenograft models. BET inhibitors cause a reduction in the expression of multiple SWI/SNF members including ARID1B, providing a potential explanation for the observed lethal interaction with ARID1A loss. Our data indicate that BET inhibition may represent a novel treatment strategy for a subset of ARID1A mutated ovarian clear cell carcinomas.
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Affiliation(s)
- Katrien Berns
- Division of Molecular Carcinogenesis and Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, Amsterdam, 1066 CX, The Netherlands.
| | - Joseph J Caumanns
- Gynaecologic Oncology, Cancer Research Centre Groningen, University Medical Center Groningen, University of Groningen, Hanzeplein 1, Groningen, 9713 GZ, The Netherlands
| | - E Marielle Hijmans
- Division of Molecular Carcinogenesis and Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, Amsterdam, 1066 CX, The Netherlands
| | - Annemiek M C Gennissen
- Division of Molecular Carcinogenesis and Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, Amsterdam, 1066 CX, The Netherlands
| | - Tesa M Severson
- Division of Molecular Carcinogenesis and Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, Amsterdam, 1066 CX, The Netherlands
| | - Bastiaan Evers
- Division of Molecular Carcinogenesis and Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, Amsterdam, 1066 CX, The Netherlands
| | - G Bea A Wisman
- Gynaecologic Oncology, Cancer Research Centre Groningen, University Medical Center Groningen, University of Groningen, Hanzeplein 1, Groningen, 9713 GZ, The Netherlands
| | - Gert Jan Meersma
- Gynaecologic Oncology, Cancer Research Centre Groningen, University Medical Center Groningen, University of Groningen, Hanzeplein 1, Groningen, 9713 GZ, The Netherlands
| | - Cor Lieftink
- Division of Molecular Carcinogenesis and Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, Amsterdam, 1066 CX, The Netherlands
| | - Roderick L Beijersbergen
- Division of Molecular Carcinogenesis and Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, Amsterdam, 1066 CX, The Netherlands
| | - Hiroaki Itamochi
- Department of Obstetrics and Gynaecology, Iwate Medical University School of Medicine, Iwate, Morioka, 020-8505, Japan
| | - Ate G J van der Zee
- Gynaecologic Oncology, Cancer Research Centre Groningen, University Medical Center Groningen, University of Groningen, Hanzeplein 1, Groningen, 9713 GZ, The Netherlands
| | - Steven de Jong
- Medical Oncology, Cancer Research Centre Groningen, University Medical Center Groningen, University of Groningen, Hanzeplein 1, Groningen, 9713 GZ, The Netherlands
| | - René Bernards
- Division of Molecular Carcinogenesis and Oncode Institute, The Netherlands Cancer Institute, Plesmanlaan 121, Amsterdam, 1066 CX, The Netherlands.
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18
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Su J, Liu X, Zhang S, Yan F, Zhang Q, Chen J. A theoretical insight into selectivity of inhibitors toward two domains of bromodomain-containing protein 4 using molecular dynamics simulations. Chem Biol Drug Des 2017; 91:828-840. [DOI: 10.1111/cbdd.13148] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2017] [Revised: 10/22/2017] [Accepted: 11/01/2017] [Indexed: 12/16/2022]
Affiliation(s)
- Jing Su
- School of Physics and Electronics; Shandong Normal University; Jinan China
| | - Xinguo Liu
- School of Physics and Electronics; Shandong Normal University; Jinan China
| | - Shaolong Zhang
- School of Physics and Electronics; Shandong Normal University; Jinan China
| | - Fangfang Yan
- School of Physics and Electronics; Shandong Normal University; Jinan China
| | - Qinggang Zhang
- School of Physics and Electronics; Shandong Normal University; Jinan China
| | - Jianzhong Chen
- School of Science; Shandong Jiaotong University; Jinan China
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19
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Xu Y, Vakoc CR. Targeting Cancer Cells with BET Bromodomain Inhibitors. Cold Spring Harb Perspect Med 2017; 7:cshperspect.a026674. [PMID: 28213432 DOI: 10.1101/cshperspect.a026674] [Citation(s) in RCA: 134] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Cancer cells are often hypersensitive to the targeting of transcriptional regulators, which may reflect the deregulated gene expression programs that underlie malignant transformation. One of the most prominent transcriptional vulnerabilities in human cancer to emerge in recent years is the bromodomain and extraterminal (BET) family of proteins, which are coactivators that link acetylated transcription factors and histones to the activation of RNA polymerase II. Despite unclear mechanisms underlying the gene specificity of BET protein function, small molecules targeting these regulators preferentially suppress the transcription of cancer-promoting genes. As a consequence, BET inhibitors elicit anticancer activity in numerous malignant contexts at doses that can be tolerated by normal tissues, a finding supported by animal studies and by phase I clinical trials in human cancer patients. In this review, we will discuss the remarkable, and often perplexing, therapeutic effects of BET bromodomain inhibition in cancer.
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Affiliation(s)
- Yali Xu
- Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724
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20
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Knockdown of epigenetic transcriptional co-regulator Brd2a disrupts apoptosis and proper formation of hindbrain and midbrain-hindbrain boundary (MHB) region in zebrafish. Mech Dev 2017; 146:10-30. [PMID: 28549975 DOI: 10.1016/j.mod.2017.05.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 05/17/2017] [Accepted: 05/22/2017] [Indexed: 01/03/2023]
Abstract
Brd2 is a member of the bromodomain-extraterminal domain (BET) family of proteins and functions as an acetyl-histone-directed transcriptional co-regulator and recruitment scaffold in chromatin modification complexes affecting signal-dependent transcription. While Brd2 acts as a protooncogene in mammalian blood, developmental studies link it to regulation of neuronal apoptosis and epilepsy, and complete knockout of the gene is invariably embryonic lethal. In Drosophila, the Brd2 homolog acts as a maternal effect factor necessary for segment formation and identity and proper expression of homeotic loci, including Ultrabithorax and engrailed. To test the various roles attributed to Brd2 in a single developmental system representing a non-mammalian vertebrate, we conducted a phenotypic characterization of Brd2a deficient zebrafish embryos produced by morpholino knockdown and corroborated by Crispr-Cas9 disruption and small molecule inhibitor treatments. brd2aMO morphants exhibit reduced hindbrain with an ill-defined midbrain-hindbrain boundary (MHB) region; irregular notochord, neural tube, and somites; and abnormalities in ventral trunk and ventral nerve cord interneuron positioning. Using whole mount TUNEL and confocal microscopy, we uncover a significant decrease, then a dramatic increase, of p53-independent cell death at the start and end of segmentation, respectively. In contrast, using qualitative and quantitative analyses of BrdU incorporation, phosphohistone H3-tagging, and flow cytometry, we detect little effect of Brd2a knockdown on overall proliferation levels in embryos. RNA in situ hybridization shows reduced or absent expression of homeobox gene eng2a and paired box gene pax2a, in the hindbrain domain of the MHB region, and an overabundance of pax2a-positive kidney progenitors, in knockdowns. Together, these results suggest an evolutionarily conserved role for Brd2 in the proper formation and/or patterning of segmented tissues, including the vertebrate CNS, where it acts as a bi-modal regulator of apoptosis, and is necessary, directly or indirectly, for proper expression of genes that pattern the MHB and/or regulate differentiation in the anterior hindbrain.
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21
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Su J, Liu X, Zhang S, Yan F, Zhang Q, Chen J. A computational insight into binding modes of inhibitors XD29, XD35, and XD28 to bromodomain-containing protein 4 based on molecular dynamics simulations. J Biomol Struct Dyn 2017; 36:1212-1224. [DOI: 10.1080/07391102.2017.1317666] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Jing Su
- School of Physics and Electronics, Shandong Normal University, Jinan, 250014, China
| | - Xinguo Liu
- School of Physics and Electronics, Shandong Normal University, Jinan, 250014, China
| | - Shaolong Zhang
- School of Physics and Electronics, Shandong Normal University, Jinan, 250014, China
| | - Fangfang Yan
- School of Physics and Electronics, Shandong Normal University, Jinan, 250014, China
| | - Qinggang Zhang
- School of Physics and Electronics, Shandong Normal University, Jinan, 250014, China
| | - Jianzhong Chen
- School of Science, Shandong Jiaotong University, Jinan, 250357, China
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22
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Taniguchi Y. The Bromodomain and Extra-Terminal Domain (BET) Family: Functional Anatomy of BET Paralogous Proteins. Int J Mol Sci 2016; 17:ijms17111849. [PMID: 27827996 PMCID: PMC5133849 DOI: 10.3390/ijms17111849] [Citation(s) in RCA: 187] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 10/31/2016] [Accepted: 11/02/2016] [Indexed: 12/31/2022] Open
Abstract
The Bromodomain and Extra-Terminal Domain (BET) family of proteins is characterized by the presence of two tandem bromodomains and an extra-terminal domain. The mammalian BET family of proteins comprises BRD2, BRD3, BRD4, and BRDT, which are encoded by paralogous genes that may have been generated by repeated duplication of an ancestral gene during evolution. Bromodomains that can specifically bind acetylated lysine residues in histones serve as chromatin-targeting modules that decipher the histone acetylation code. BET proteins play a crucial role in regulating gene transcription through epigenetic interactions between bromodomains and acetylated histones during cellular proliferation and differentiation processes. On the other hand, BET proteins have been reported to mediate latent viral infection in host cells and be involved in oncogenesis. Human BRD4 is involved in multiple processes of the DNA virus life cycle, including viral replication, genome maintenance, and gene transcription through interaction with viral proteins. Aberrant BRD4 expression contributes to carcinogenesis by mediating hyperacetylation of the chromatin containing the cell proliferation-promoting genes. BET bromodomain blockade using small-molecule inhibitors gives rise to selective repression of the transcriptional network driven by c-MYC These inhibitors are expected to be potential therapeutic drugs for a wide range of cancers. This review presents an overview of the basic roles of BET proteins and highlights the pathological functions of BET and the recent developments in cancer therapy targeting BET proteins in animal models.
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Affiliation(s)
- Yasushi Taniguchi
- Division of Basic Molecular Science and Molecular Medicine, School of Medicine, Tokai University, Isehara, Kanagawa 259-1193, Japan.
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23
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Andrieu G, Tran AH, Strissel KJ, Denis GV. BRD4 Regulates Breast Cancer Dissemination through Jagged1/Notch1 Signaling. Cancer Res 2016; 76:6555-6567. [PMID: 27651315 DOI: 10.1158/0008-5472.can-16-0559] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 09/06/2016] [Accepted: 09/12/2016] [Indexed: 12/14/2022]
Abstract
The bromodomain and extraterminal (BET) proteins are epigenetic "readers" of acetylated histones in chromatin and have been identified as promising therapeutic targets in diverse cancers. However, it remains unclear how individual family members participate in cancer progression and small molecule inhibitors such as JQ1 can target functionally independent BET proteins. Here, we report a signaling pathway involving BRD4 and the ligand/receptor pair Jagged1/Notch1 that sustains triple-negative breast cancer migration and invasion. BRD4, but not BRD2 or BRD3, regulated Jagged1 expression and Notch1 signaling. BRD4-selective knockdown suppressed Notch1 activity and impeded breast cancer migration and invasion. BRD4 was required for IL6-stimulated, Notch1-induced migration and invasion, coupling microenvironment inflammation with cancer propagation. Moreover, in patients, BRD4 and Jagged1 expression positively correlated with the presence of distant metastases. These results identify a BRD4/Jagged1/Notch1 signaling pathway that is critical for dissemination of triple-negative breast cancer. Cancer Res; 76(22); 6555-67. ©2016 AACR.
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Affiliation(s)
- Guillaume Andrieu
- Cancer Center, Boston University School of Medicine, Boston, Massachusetts
| | - Anna H Tran
- Cancer Center, Boston University School of Medicine, Boston, Massachusetts
| | | | - Gerald V Denis
- Cancer Center, Boston University School of Medicine, Boston, Massachusetts. .,Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, Massachusetts
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24
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Andrieu G, Belkina AC, Denis GV. Clinical trials for BET inhibitors run ahead of the science. DRUG DISCOVERY TODAY. TECHNOLOGIES 2016; 19:45-50. [PMID: 27769357 DOI: 10.1016/j.ddtec.2016.06.004] [Citation(s) in RCA: 179] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 05/21/2016] [Accepted: 06/02/2016] [Indexed: 12/16/2022]
Abstract
Several cancer clinical trials for small molecule inhibitors of BET bromodomain proteins have been initiated. There is enthusiasm for the anti-proliferative effect of inhibiting BRD4, one of the targets of these inhibitors, which is thought to cooperate with MYC, a long-desired target for cancer therapeutics. However, no current inhibitor is selective for BRD4 among the three somatic BET proteins, which include BRD2 and BRD3; their respective functions are partially overlapping and none are functionally redundant with BRD4. Each BET protein controls distinct transcriptional pathways that are important for functions beyond cancer cell proliferation, including insulin production, cytokine gene transcription, T cell differentiation, adipogenesis and most seriously, active repression of dangerous latent viruses like HIV. BET inhibitors have been shown to reactivate HIV in human cells. Failure to appreciate that at concentrations used, no available BET inhibitor is member-selective, or to develop a sound biological basis to understand the diverse functions of BET proteins before undertaking for these clinical trials is reckless and likely to lead to adverse events. More mechanistic information from new basic science studies should enable proper focus on the most relevant cancers and define the expected side effect profiles.
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Affiliation(s)
- Guillaume Andrieu
- Department of Medicine, Cancer Research Center, Boston University School of Medicine, Boston, MA 02118, United States
| | - Anna C Belkina
- Flow Cytometry Core Facility, Department of Microbiology, Boston University School of Medicine, Boston, MA 02118, United States
| | - Gerald V Denis
- Department of Medicine, Cancer Research Center, Boston University School of Medicine, Boston, MA 02118, United States; Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Boston, MA 02118, United States.
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Abstract
BET proteins have recently become recognized for their role in a broad range of cancers and are defined by the presence of two acetyl-histone reading bromodomains and an ET domain. This family of proteins includes BRD2, BRD3, BRD4, and BRDT. BRD4 is the most-studied BET protein in cancer, and normally serves as an epigenetic reader that links active chromatin marks to transcriptional elongation through activation of RNA polymerase II. The role of BRD3 and BRD4 first became known in cancer as mutant oncoproteins fused to the p300-recruiting NUT protein in a rare aggressive subtype of squamous cell cancer known as NUT midline carcinoma (NMC). BET inhibitors are acetyl-histone mimetics that specifically bind BET bromodomains, competitively inhibiting its engagement with chromatin. The antineoplastic effects of BET inhibitors were first demonstrated in NMC and have since been shown to be effective at inhibiting the growth of many different cancers, particularly acute leukemia. BET inhibitors have also been instrumental as tool compounds that have demonstrated the key role of BRD4 in driving NMC and non-NMC cancer growth. Many clinical trials enrolling patients with hematologic and solid tumors are ongoing, with encouraging preliminary findings. BET proteins BRD2, BRD3, and BRD4 are expressed in nearly all cells of the body, so there are concerns of toxicity with BET inhibitors, as well as the development of resistance. Toxicity and resistance may be overcome by combining BET inhibitors with other targeted inhibitors, or through the use of novel BET inhibitor derivatives.
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Affiliation(s)
- C A French
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States.
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26
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Deeney JT, Belkina AC, Shirihai OS, Corkey BE, Denis GV. BET Bromodomain Proteins Brd2, Brd3 and Brd4 Selectively Regulate Metabolic Pathways in the Pancreatic β-Cell. PLoS One 2016; 11:e0151329. [PMID: 27008626 PMCID: PMC4805167 DOI: 10.1371/journal.pone.0151329] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 02/26/2016] [Indexed: 11/18/2022] Open
Abstract
Displacement of Bromodomain and Extra-Terminal (BET) proteins from chromatin has promise for cancer and inflammatory disease treatments, but roles of BET proteins in metabolic disease remain unexplored. Small molecule BET inhibitors, such as JQ1, block BET protein binding to acetylated lysines, but lack selectivity within the BET family (Brd2, Brd3, Brd4, Brdt), making it difficult to disentangle contributions of each family member to transcriptional and cellular outcomes. Here, we demonstrate multiple improvements in pancreatic β-cells upon BET inhibition with JQ1 or BET-specific siRNAs. JQ1 (50–400 nM) increases insulin secretion from INS-1 cells in a concentration dependent manner. JQ1 increases insulin content in INS-1 cells, accounting for increased secretion, in both rat and human islets. Higher concentrations of JQ1 decrease intracellular triglyceride stores in INS-1 cells, a result of increased fatty acid oxidation. Specific inhibition of both Brd2 and Brd4 enhances insulin transcription, leading to increased insulin content. Inhibition of Brd2 alone increases fatty acid oxidation. Overlapping yet discrete roles for individual BET proteins in metabolic regulation suggest new isoform-selective BET inhibitors may be useful to treat insulin resistant/diabetic patients. Results imply that cancer and diseases of chronic inflammation or disordered metabolism are related through shared chromatin regulatory mechanisms.
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Affiliation(s)
- Jude T. Deeney
- Department of Medicine, Section of Endocrinology, Obesity Research Center, Evans Biomedical Research Center; Boston University School of Medicine, 650 Albany Street, X804, Boston, Massachusetts 02118, United States of America
| | - Anna C. Belkina
- Flow Cytometry Core Facility, Boston University School of Medicine, 650 Albany Street, X326, Boston, Massachusetts 02118, United States of America
| | - Orian S. Shirihai
- Department of Medicine, Section of Endocrinology, Obesity Research Center, Evans Biomedical Research Center; Boston University School of Medicine, 650 Albany Street, X804, Boston, Massachusetts 02118, United States of America
| | - Barbara E. Corkey
- Department of Medicine, Section of Endocrinology, Obesity Research Center, Evans Biomedical Research Center; Boston University School of Medicine, 650 Albany Street, X804, Boston, Massachusetts 02118, United States of America
| | - Gerald V. Denis
- Department of Pharmacology and Experimental Therapeutics, and Section of Hematology/ Oncology, Cancer Research Center; Boston University School of Medicine, 72 East Concord Street, K520, Boston, Massachusetts 02118, United States of America
- * E-mail:
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The acetyllysine reader BRD3R promotes human nuclear reprogramming and regulates mitosis. Nat Commun 2016; 7:10869. [PMID: 26947130 PMCID: PMC4786677 DOI: 10.1038/ncomms10869] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 01/28/2016] [Indexed: 12/22/2022] Open
Abstract
It is well known that both recipient cells and donor nuclei demonstrate a mitotic advantage as observed in the traditional reprogramming with somatic cell nuclear transfer (SCNT). However, it is not known whether a specific mitotic factor plays a critical role in reprogramming. Here we identify an isoform of human bromodomain-containing 3 (BRD3), BRD3R (BRD3 with Reprogramming activity), as a reprogramming factor. BRD3R positively regulates mitosis during reprogramming, upregulates a large set of mitotic genes at early stages of reprogramming, and associates with mitotic chromatin. Interestingly, a set of the mitotic genes upregulated by BRD3R constitutes a pluripotent molecular signature. The two BRD3 isoforms display differential binding to acetylated histones. Our results suggest a molecular interpretation for the mitotic advantage in reprogramming and show that mitosis may be a driving force of reprogramming. The reprogramming of fibroblasts to pluripotent stem cells has been well documented but there is interest in identifying additional factors involved. Here, the authors perform a screen of human kinases and show that the bromodomain protein, BRD3R, can promote reprogramming and suggest a role for this factor in regulating mitosis.
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28
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Stonestrom AJ, Hsu SC, Werner MT, Blobel GA. Erythropoiesis provides a BRD's eye view of BET protein function. DRUG DISCOVERY TODAY. TECHNOLOGIES 2016; 19:23-28. [PMID: 27769353 PMCID: PMC5116323 DOI: 10.1016/j.ddtec.2016.05.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Revised: 05/11/2016] [Accepted: 05/17/2016] [Indexed: 06/06/2023]
Abstract
Pharmacologic inhibitors of the bromodomain and extra-terminal motif (BET) protein family are in clinical trials for the treatment of hematologic malignancies, yet the functions of individual BET proteins remain largely uncharacterized. We review the molecular roles of BETs in the context of erythropoiesis. Studies in this lineage have provided valuable insights into their mechanisms of action, and helped define the individual and overlapping functions of BET protein family members BRD2, BRD3, and BRD4. These studies have important ramifications for our understanding of the molecular and physiologic roles of BET proteins, and provide a framework for elucidating some of the beneficial and adverse effects of pharmacologic inhibitors.
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Affiliation(s)
- Aaron J Stonestrom
- Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Sarah C Hsu
- Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Michael T Werner
- Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Gerd A Blobel
- Division of Hematology, Children's Hospital of Philadelphia, Philadelphia, PA, United States.
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The Epigenetic Reader BRD2 as a Specific Modulator of PAI-1 Expression in Lipopolysaccharide-Stimulated Mouse Primary Astrocytes. Neurochem Res 2015; 40:2211-9. [PMID: 26349765 DOI: 10.1007/s11064-015-1710-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 08/13/2015] [Accepted: 08/25/2015] [Indexed: 12/19/2022]
Abstract
The post translational modification of lysine acetylation is a key mechanism that regulates chromatin structure. Epigenetic readers, such as the BET domains, are responsible for reading histone lysine acetylation which is a hallmark of open chromatin structure, further providing a scaffold that can be accessed by RNA polymerases as well as transcription factors. Recently, several reports have assessed and highlighted the roles of epigenetic readers in various cellular contexts. However, little is known about their role in the regulation of inflammatory genes, which is critical in exquisitely tuning inflammatory responses to a variety of immune stimuli. In this study, we investigated the role of epigenetic readers BRD2 and BRD4 in the lipopolysaccharide (LPS)-induced immune responses in mouse primary astrocytes. Inflammatory stimulation by LPS showed that the levels of Brd2 mRNA and protein were increased, while Brd4 mRNA levels did not change. Knocking down of Brd2 mRNA using specific small interfering RNA (siRNA) in cultured mouse primary astrocytes inhibited LPS-induced mRNA expression and secretion of plasminogen activator inhibitor-1 (PAI-1). However, no other pro-inflammatory cytokines, such as Il-6, Il-1β and Tnf-α, were affected. Indeed, treatment with bromodomain-containing protein inhibitor, JQ1, blocked Pai-1 mRNA expression through the inhibition of direct BRD2 protein-binding and active histone modification on Pai-1 promoter. Taken together, our data suggest that BRD2 is involved in the modulation of neuroinflammatory responses through PAI-1 and via the regulation of epigenetic reader BET protein, further providing a potential novel therapeutic strategy in neuroinflammatory diseases.
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30
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Sun R, Wu Y, Wang Y, Zang K, Wei H, Wang F, Yu M. DNA methylation regulates bromodomain-containing protein 2 expression during adipocyte differentiation. Mol Cell Biochem 2015; 402:23-31. [DOI: 10.1007/s11010-014-2310-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 12/20/2014] [Indexed: 01/24/2023]
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31
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Kingston RE, Tamkun JW. Transcriptional regulation by trithorax-group proteins. Cold Spring Harb Perspect Biol 2014; 6:a019349. [PMID: 25274705 DOI: 10.1101/cshperspect.a019349] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The trithorax group of genes (trxG) was identified in mutational screens that examined developmental phenotypes and suppression of Polycomb mutant phenotypes. The protein products of these genes are primarily involved in gene activation, although some can also have repressive effects. There is no central function for these proteins. Some move nucleosomes about on the genome in an ATP-dependent manner, some covalently modify histones such as methylating lysine 4 of histone H3, and some directly interact with the transcription machinery or are a part of that machinery. It is interesting to consider why these specific members of large families of functionally related proteins have strong developmental phenotypes.
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Affiliation(s)
- Robert E Kingston
- Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts 02114
| | - John W Tamkun
- Department of Molecular, Cell and Developmental Biology, University of California, Santa Cruz, Santa Cruz, California 95064
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32
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Garcia-Gutierrez P, Juarez-Vicente F, Wolgemuth DJ, Garcia-Dominguez M. Pleiotrophin antagonizes Brd2 during neuronal differentiation. J Cell Sci 2014; 127:2554-64. [PMID: 24695857 DOI: 10.1242/jcs.147462] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Bromodomain-containing protein 2 (Brd2) is a BET family chromatin adaptor required for expression of cell-cycle-associated genes and therefore involved in cell cycle progression. Brd2 is expressed in proliferating neuronal progenitors, displays cell-cycle-stimulating activity and, when overexpressed, impairs neuronal differentiation. Paradoxically, Brd2 is also detected in differentiating neurons. To shed light on the role of Brd2 in the transition from cell proliferation to differentiation, we had previously looked for proteins that interacted with Brd2 upon induction of neuronal differentiation. Surprisingly, we identified the growth factor pleiotrophin (Ptn). Here, we show that Ptn antagonized the cell-cycle-stimulating activity associated with Brd2, thus enhancing induced neuronal differentiation. Moreover, Ptn knockdown reduced neuronal differentiation. We analyzed Ptn-mediated antagonism of Brd2 in a cell differentiation model and in two embryonic processes associated with the neural tube: spinal cord neurogenesis and neural crest migration. Finally, we investigated the mechanisms of Ptn-mediated antagonism and determined that Ptn destabilizes the association of Brd2 with chromatin. Thus, Ptn-mediated Brd2 antagonism emerges as a modulation system accounting for the balance between cell proliferation and differentiation in the vertebrate nervous system.
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Affiliation(s)
- Pablo Garcia-Gutierrez
- Stem Cells Department, Andalusian Center for Molecular Biology and Regenerative Medicine (CABIMER) (Consejo Superior de Investigaciones Cientificas (CSIC), Junta de Andalucía, Universidad de Sevilla, Universidad Pablo de Olavide), Seville 41092, Spain
| | - Francisco Juarez-Vicente
- Stem Cells Department, Andalusian Center for Molecular Biology and Regenerative Medicine (CABIMER) (Consejo Superior de Investigaciones Cientificas (CSIC), Junta de Andalucía, Universidad de Sevilla, Universidad Pablo de Olavide), Seville 41092, Spain
| | - Debra J Wolgemuth
- Department of Genetics and Development, Columbia University Medical Center, New York, NY 10032, USA
| | - Mario Garcia-Dominguez
- Stem Cells Department, Andalusian Center for Molecular Biology and Regenerative Medicine (CABIMER) (Consejo Superior de Investigaciones Cientificas (CSIC), Junta de Andalucía, Universidad de Sevilla, Universidad Pablo de Olavide), Seville 41092, Spain
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Dittmann A, Werner T, Chung CW, Savitski MM, Fälth Savitski M, Grandi P, Hopf C, Lindon M, Neubauer G, Prinjha RK, Bantscheff M, Drewes G. The commonly used PI3-kinase probe LY294002 is an inhibitor of BET bromodomains. ACS Chem Biol 2014; 9:495-502. [PMID: 24533473 DOI: 10.1021/cb400789e] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A commonly used small-molecule probe in cell-signaling research is the phosphoinositide 3-kinase inhibitor LY294002. Quantitative chemoproteomic profiling shows that LY294002 and LY303511, a close analogue devoid of PI3K activity, inhibit the BET bromodomain proteins BRD2, BRD3, and BRD4 that comprise a family of targets structurally unrelated to PI3K. Both compounds competitively inhibit acetyl-lysine binding of the first but not the second bromodomain of BET proteins in cell extracts. X-ray crystallography shows that the chromen-4-one scaffold represents a new bromodomain pharmacophore and establishes LY294002 as a dual kinase and BET-bromodomain inhibitor, whereas LY303511 exhibits anti-inflammatory and antiproliferative effects similar to the recently discovered BET inhibitors.
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Affiliation(s)
- Antje Dittmann
- Cellzome GmbH, Meyerhofstrasse
1, 69117 Heidelberg, Germany
| | - Thilo Werner
- Cellzome GmbH, Meyerhofstrasse
1, 69117 Heidelberg, Germany
| | - Chun-Wa Chung
- Molecular
Discovery Research, GlaxoSmithKline Medicines Research Centre, Stevenage SG1 2NY, United Kingdom
| | | | | | - Paola Grandi
- Cellzome GmbH, Meyerhofstrasse
1, 69117 Heidelberg, Germany
| | - Carsten Hopf
- Cellzome GmbH, Meyerhofstrasse
1, 69117 Heidelberg, Germany
| | - Matthew Lindon
- Epinova
DPU, GlaxoSmithKline Medicines Research Centre, Gunnels Wood
Road, Stevenage SG1 2NY, United Kingdom
| | - Gitte Neubauer
- Cellzome GmbH, Meyerhofstrasse
1, 69117 Heidelberg, Germany
| | - Rabinder K. Prinjha
- Epinova
DPU, GlaxoSmithKline Medicines Research Centre, Gunnels Wood
Road, Stevenage SG1 2NY, United Kingdom
| | | | - Gerard Drewes
- Cellzome GmbH, Meyerhofstrasse
1, 69117 Heidelberg, Germany
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Gallenkamp D, Gelato KA, Haendler B, Weinmann H. Bromodomains and their pharmacological inhibitors. ChemMedChem 2014; 9:438-64. [PMID: 24497428 DOI: 10.1002/cmdc.201300434] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 12/23/2013] [Indexed: 12/15/2022]
Abstract
Over 60 bromodomains belonging to proteins with very different functions have been identified in humans. Several of them interact with acetylated lysine residues, leading to the recruitment and stabilization of protein complexes. The bromodomain and extra-terminal domain (BET) proteins contain tandem bromodomains which bind to acetylated histones and are thereby implicated in a number of DNA-centered processes, including the regulation of gene expression. The recent identification of inhibitors of BET and non-BET bromodomains is one of the few examples in which effective blockade of a protein-protein interaction can be achieved with a small molecule. This has led to major strides in the understanding of the function of bromodomain-containing proteins and their involvement in diseases such as cancer and inflammation. Indeed, BET bromodomain inhibitors are now being clinically evaluated for the treatment of hematological tumors and have also been tested in clinical trials for the relatively rare BRD-NUT midline carcinoma. This review gives an overview of the newest developments in the field, with a focus on the biology of selected bromodomain proteins on the one hand, and on reported pharmacological inhibitors on the other, including recent examples from the patent literature.
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Liu S, Walker SR, Nelson EA, Cerulli R, Xiang M, Toniolo PA, Qi J, Stone RM, Wadleigh M, Bradner JE, Frank DA. Targeting STAT5 in hematologic malignancies through inhibition of the bromodomain and extra-terminal (BET) bromodomain protein BRD2. Mol Cancer Ther 2014; 13:1194-205. [PMID: 24435449 DOI: 10.1158/1535-7163.mct-13-0341] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The transcription factor signal STAT5 is constitutively activated in a wide range of leukemias and lymphomas, and drives the expression of genes necessary for proliferation, survival, and self-renewal. Thus, targeting STAT5 is an appealing therapeutic strategy for hematologic malignancies. Given the importance of bromodomain-containing proteins in transcriptional regulation, we considered the hypothesis that a pharmacologic bromodomain inhibitor could inhibit STAT5-dependent gene expression. We found that the small-molecule bromodomain and extra-terminal (BET) bromodomain inhibitor JQ1 decreases STAT5-dependent (but not STAT3-dependent) transcription of both heterologous reporter genes and endogenous STAT5 target genes. JQ1 reduces STAT5 function in leukemia and lymphoma cells with constitutive STAT5 activation, or inducibly activated by cytokine stimulation. Among the BET bromodomain subfamily of proteins, it seems that BRD2 is the critical mediator for STAT5 activity. In experimental models of acute T-cell lymphoblastic leukemias, where activated STAT5 contributes to leukemia cell survival, Brd2 knockdown or JQ1 treatment shows strong synergy with tyrosine kinase inhibitors (TKI) in inducing apoptosis in leukemia cells. In contrast, mononuclear cells isolated form umbilical cord blood, which is enriched in normal hematopoietic precursor cells, were unaffected by these combinations. These findings indicate a unique functional association between BRD2 and STAT5, and suggest that combinations of JQ1 and TKIs may be an important rational strategy for treating leukemias and lymphomas driven by constitutive STAT5 activation.
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Affiliation(s)
- Suhu Liu
- Authors' Affiliations: Department of Medical Oncology, Dana-Farber Cancer Institute, and Departments of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts; and Department of Immunology, Institute of Biomedical Science, University of Sao Paulo, Sao Paulo, Brazil
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Belkina AC, Blanton WP, Nikolajczyk BS, Denis GV. The double bromodomain protein Brd2 promotes B cell expansion and mitogenesis. J Leukoc Biol 2013; 95:451-60. [PMID: 24319289 DOI: 10.1189/jlb.1112588] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Bromodomain-containing transcriptional regulators represent new epigenetic targets in different hematologic malignancies. However, bromodomain-mediated mechanisms that couple histone acetylation to transcription in lymphopoiesis and govern mature lymphocyte mitogenesis are poorly understood. Brd2, a transcriptional coregulator that contains dual bromodomains and an extraterminal domain (the BET family), couples chromatin to cell-cycle progression. We reported previously the first functional characterization of a BET protein as an effector of mammalian mitogenic signal transduction: Eμ-Brd2 Tg mice develop "activated B cell" diffuse large B cell lymphoma. No other animal models exist for genetic or lentiviral expression of BET proteins, hampering testing of novel anti-BET anticancer drugs, such as JQ1. We transduced HSCs with Brd2 lentivirus and reconstituted recipient mice to test the hypothesis that Brd2 regulates hematopoiesis in BM and mitogenesis in the periphery. Forced expression of Brd2 provides an expansion advantage to the donor-derived B cell compartment in BM and increases mature B cell mitogenic responsiveness in vitro. Brd2 binds the cyclin A promoter in B cells, shown by ChIP, and increases cyclin A mRNA and protein levels, and S-phase progression in vitro in mitogen-stimulated primary B cells, but not T cells, reinforcing results from Eμ-Brd2 mice. The small molecule BET inhibitor JQ1 reduces B cell mitogenesis, consistent with the interpretation that BET inhibitors are antiproliferative. Brd2-specific knockdown experiments show that Brd2 is also required for hematopoiesis. We conclude that Brd2 plays a critical, independent role in regulation of mitogenic response genes, particularly cyclin A, in B cells.
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Affiliation(s)
- Anna C Belkina
- 1.72 East Concord St., Rm. K520, Boston, MA 02118, USA. ; Twitter: http://www.twitter.com/GdenisBoston
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Abstract
INTRODUCTION The bromodomain (BRD) and extra-C terminal domain (BET) protein family consists of four members (BRD2, BRD3, BRD4 and BRDT). These "epigenetic readers" bind to acetyllysine (KAc) residues on the tails of histones H3 and H4, and regulate chromatin structure and gene expression. There is increasing evidence of their role in human disease, and recently a number of small-molecule inhibitors have been reported. There is increasing interest in the inhibition of BET proteins for a variety of therapeutic applications that have resulted in considerable patent activity from academia and biotechnology and pharmaceutical companies. AREAS COVERED Data supporting the use of BET inhibitors in treating disease are outlined, and the current patent literature is discussed. The survey is focused on patents claiming compounds as BET inhibitors and additional patents covering compounds now reported as BET inhibitors have been included. EXPERT OPINION There is now compelling preclinical data demonstrating BET inhibition as a strategy to target processes known to be involved in disease development and progression with clinical trials of two bona fide BET inhibitors now underway. Patent activity in this area is increasing with initial activity focused on variations to reported BET inhibitors and more recent patents disclosing novel chemotypes as BET inhibitors.
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Affiliation(s)
- Jean-Marc Garnier
- The Walter and Eliza Hall Institute of Medical Research , 1G Royal Pde, Parkville, VIC, 3052 , Australia +61 3 9345 2957 ; +61 3 9347 0852 ;
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Brd2 inhibits adipogenesis via the ERK1/2 signaling pathway in 3T3-L1 adipocytes. PLoS One 2013; 8:e78536. [PMID: 24194944 PMCID: PMC3806839 DOI: 10.1371/journal.pone.0078536] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Accepted: 09/20/2013] [Indexed: 12/12/2022] Open
Abstract
Bromodomain-containing protein 2 (Brd2) is a nuclear serine/threonine kinase involved in transcriptional regulation. In 3T3-L1 adipocytes, Brd2 normally co-represses PPARγ (peroxisome proliferator-activated receptor gamma) and inhibits adipogenesis. Here, we show that Brd2 over-expression in preadipocytes inhibits their differentiation into adipocytes, while Brd2 knockdown promotes adipogenic differentiation in vitro and forces cells to undergo adipogenesis independent of the MDI (methyisobutylxanthane, dexamethasone and insulin) induction. In this study, the two key transcription factors for adipogenesis, PPARγ and C/EBPα (CCAAT/enhancer binding protein-α) were persistently expressed during the differentiation of preadipocytes to mature adipocytes in Brd2 knockdown 3T3-L1 cells, but their expression was inhibited in cells in which Brd2 was overexpressed. To investigate the role of Brd2 in signal transduction we examined the expression of several signaling molecules involved in the regulation of gene expression and cell differentiation by immunoblotting assay. Down-regulation of Brd2 expression in 3T3-L1 cells led to a decrease in extracellular signal-regulated kinase1/2 (ERK1/2) activity and, conversely, the up-regulation of Brd2 leads to increase in ERK1/2 phosphorylation. Nevertheless, changes in Brd2 expression do not affect the activities of JNK and p38 MAPK. In addition, the phosphorylation of Rafs is not affected by changes in Brd2 expression in 3T3-L1 cells. MEK inhibitor UO126 partly restores differentiation of 3T3-L1 cells that overexpress Brd2. In conclusion, these results indicate that Brd2 regulates ERK1/2 activity independently of Raf signaling in 3T3-L1 adipocytes.
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Segura MF, Fontanals-Cirera B, Gaziel-Sovran A, Guijarro MV, Hanniford D, Zhang G, González-Gomez P, Morante M, Jubierre L, Zhang W, Darvishian F, Ohlmeyer M, Osman I, Zhou MM, Hernando E. BRD4 sustains melanoma proliferation and represents a new target for epigenetic therapy. Cancer Res 2013; 73:6264-76. [PMID: 23950209 DOI: 10.1158/0008-5472.can-13-0122-t] [Citation(s) in RCA: 177] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Metastatic melanoma remains a mostly incurable disease. Although newly approved targeted therapies are efficacious in a subset of patients, resistance and relapse rapidly ensue. Alternative therapeutic strategies to manipulate epigenetic regulators and disrupt the transcriptional program that maintains tumor cell identity are emerging. Bromodomain and extraterminal domain (BET) proteins are epigenome readers known to exert key roles at the interface between chromatin remodeling and transcriptional regulation. Here, we report that BRD4, a BET family member, is significantly upregulated in primary and metastatic melanoma tissues compared with melanocytes and nevi. Treatment with BET inhibitors impaired melanoma cell proliferation in vitro and tumor growth and metastatic behavior in vivo, effects that were mostly recapitulated by individual silencing of BRD4. RNA sequencing of BET inhibitor-treated cells followed by Gene Ontology analysis showed a striking impact on transcriptional programs controlling cell growth, proliferation, cell-cycle regulation, and differentiation. In particular, we found that, rapidly after BET displacement, key cell-cycle genes (SKP2, ERK1, and c-MYC) were downregulated concomitantly with the accumulation of cyclin-dependent kinase (CDK) inhibitors (p21 and p27), followed by cell-cycle arrest. Importantly, BET inhibitor efficacy was not influenced by BRAF or NRAS mutational status, opening the possibility of using these small-molecule compounds to treat patients for whom no effective targeted therapy exists. Collectively, our study reveals a critical role for BRD4 in melanoma tumor maintenance and renders it a legitimate and novel target for epigenetic therapy directed against the core transcriptional program of melanoma.
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Affiliation(s)
- Miguel F Segura
- Authors' Affiliations: Departments of Pathology and Dermatology, New York University School of Medicine; Interdisciplinary Melanoma Cooperative Group, New York University Cancer Institute, New York University Langone Medical Center; Departments of Structural and Chemical Biology and Medicine, Icahn School of Medicine at Mount Sinai, New York, New York; Instituto de Salud Carlos III, Majadahonda, Madrid; and Laboratory of Translational Research in Childhood Cancer, Vall d'Hebrón Institut de Recerca (VHIR), Barcelona, Spain
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Merker JD, Roskin KM, Ng D, Pan C, Fisk DG, King JJ, Hoh R, Stadler M, Okumoto LM, Abidi P, Hewitt R, Jones CD, Gojenola L, Clark MJ, Zhang B, Cherry AM, George TI, Snyder M, Boyd SD, Zehnder JL, Fire AZ, Gotlib J. Comprehensive whole-genome sequencing of an early-stage primary myelofibrosis patient defines low mutational burden and non-recurrent candidate genes. Haematologica 2013; 98:1689-96. [PMID: 23872309 DOI: 10.3324/haematol.2013.092379] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
In order to identify novel somatic mutations associated with classic BCR/ABL1-negative myeloproliferative neoplasms, we performed high-coverage genome sequencing of DNA from peripheral blood granulocytes and cultured skin fibroblasts from a patient with MPL W515K-positive primary myelofibrosis. The primary myelofibrosis genome had a low somatic mutation rate, consistent with that observed in similar hematopoietic tumor genomes. Interfacing of whole-genome DNA sequence data with RNA expression data identified three somatic mutations of potential functional significance: i) a nonsense mutation in CARD6, implicated in modulation of NF-kappaB activation; ii) a 19-base pair deletion involving a potential regulatory region in the 5'-untranslated region of BRD2, implicated in transcriptional regulation and cell cycle control; and iii) a non-synonymous point mutation in KIAA0355, an uncharacterized protein. Additional mutations in three genes (CAP2, SOX30, and MFRP) were also evident, albeit with no support for expression at the RNA level. Re-sequencing of these six genes in 178 patients with polycythemia vera, essential thrombocythemia, and myelofibrosis did not identify recurrent somatic mutations in these genes. Finally, we describe methods for reducing false-positive variant calls in the analysis of hematologic malignancies with a low somatic mutation rate. This trial is registered with ClinicalTrials.gov (NCT01108159).
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Wang F, Deeney JT, Denis GV. Brd2 gene disruption causes "metabolically healthy" obesity: epigenetic and chromatin-based mechanisms that uncouple obesity from type 2 diabetes. VITAMINS AND HORMONES 2013; 91:49-75. [PMID: 23374712 DOI: 10.1016/b978-0-12-407766-9.00003-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Disturbed body energy balance can lead to obesity and obesity-driven diseases such as Type 2 diabetes, which have reached an epidemic level. Evidence indicates that obesity-induced inflammation is a major cause of insulin resistance and Type 2 diabetes. Environmental factors, such as nutrients, affect body energy balance through epigenetic or chromatin-based mechanisms. As a bromodomain and external domain family transcription regulator, Brd2 regulates expression of many genes through interpretation of chromatin codes and participates in the regulation of body energy balance and immune function. In the severely obese state, Brd2 knockdown in mice prevented obesity-induced inflammatory responses, protected animals from insulin resistance, glucose intolerance and pancreatic beta cell dysfunction, and thus uncoupled obesity from diabetes. Brd2 provides an important model for investigation of the function of transcription regulators and the development of obesity and diabetes; it also provides a possible, innovative target to treat obesity and diabetes through modulation of the function of a chromatin code reader.
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Abstract
Immune response to pathogens depends on coordinated regulation of numerous genes that contribute collectively to pathogen elimination and restoration of the integrity of the affected tissue. The pathogen-induced gene expression is governed largely by the signal-induced posttranslational histone modifications that facilitate assembly of the functionally distinct chromatin complexes. In this review, we describe the principles of chromatin-based gene regulation during innate immune responses. We discuss the ability of pathogens to hijack the host response by interfering with various arms of transcriptional machinery involved in the responses. In particular, we discuss the phenomenon of the histone mimicry where interaction between histones and transcriptional regulators is targeted by pathogens that carry the histone-like sequences (histone mimics). We show how the principle of isotone mimicry as an efficient way to control host gene expression has been sued for the development of novel anti-inflammatory pharmacological approaches.
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43
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Abstract
Retroviral infections cause a variety of cancers in animals and a number of diverse diseases in humans such as leukemia and acquired immune deficiency syndrome. Productive and efficient proviral integration is critical for retroviral function and is the key step in establishing a stable and productive infection, as well as the mechanism by which host genes are activated in leukemogenesis. Host factors are widely anticipated to be involved in all stages of the retroviral life cycle, and the identification of integrase interacting factors has the potential to increase our understanding of mechanisms by which the incoming virus might appropriate cellular proteins to target and capture host DNA sequences. Identification of MoMLV integrase interacting host factors may be key to designing efficient and benign retroviral-based gene therapy vectors; key to understanding the basic mechanism of integration; and key in designing efficient integrase inhibitors. In this review, we discuss current progress in the field of MoMLV integrase interacting proteins and possible roles for these proteins in integration.
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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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BRD4 is an atypical kinase that phosphorylates serine2 of the RNA polymerase II carboxy-terminal domain. Proc Natl Acad Sci U S A 2012; 109:6927-32. [PMID: 22509028 DOI: 10.1073/pnas.1120422109] [Citation(s) in RCA: 281] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The bromodomain protein, BRD4, has been identified recently as a therapeutic target in acute myeloid leukemia, multiple myeloma, Burkitt's lymphoma, NUT midline carcinoma, colon cancer, and inflammatory disease; its loss is a prognostic signature for metastatic breast cancer. BRD4 also contributes to regulation of both cell cycle and transcription of oncogenes, HIV, and human papilloma virus (HPV). Despite its role in a broad range of biological processes, the precise molecular mechanism of BRD4 function remains unknown. We report that BRD4 is an atypical kinase that binds to the carboxyl-terminal domain (CTD) of RNA polymerase II and directly phosphorylates its serine 2 (Ser2) sites both in vitro and in vivo under conditions where other CTD kinases are inactive. Phosphorylation of the CTD Ser2 is inhibited in vivo by a BRD4 inhibitor that blocks its binding to chromatin. Our finding that BRD4 is an RNA polymerase II CTD Ser2 kinase implicates it as a regulator of eukaryotic transcription.
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Ohta Y, Shiina T, Lohr RL, Hosomichi K, Pollin TI, Heist EJ, Suzuki S, Inoko H, Flajnik MF. Primordial linkage of β2-microglobulin to the MHC. THE JOURNAL OF IMMUNOLOGY 2011; 186:3563-71. [PMID: 21321107 DOI: 10.4049/jimmunol.1003933] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
β2-Microglobulin (β2M) is believed to have arisen in a basal jawed vertebrate (gnathostome) and is the essential L chain that associates with most MHC class I molecules. It contains a distinctive molecular structure called a constant-1 Ig superfamily domain, which is shared with other adaptive immune molecules including MHC class I and class II. Despite its structural similarity to class I and class II and its conserved function, β2M is encoded outside the MHC in all examined species from bony fish to mammals, but it is assumed to have translocated from its original location within the MHC early in gnathostome evolution. We screened a nurse shark bacterial artificial chromosome library and isolated clones containing β2M genes. A gene present in the MHC of all other vertebrates (ring3) was found in the bacterial artificial chromosome clone, and the close linkage of ring3 and β2M to MHC class I and class II genes was determined by single-strand conformational polymorphism and allele-specific PCR. This study satisfies the long-held conjecture that β2M was linked to the primordial MHC (Ur MHC); furthermore, the apparent stability of the shark genome may yield other genes predicted to have had a primordial association with the MHC specifically and with immunity in general.
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Affiliation(s)
- Yuko Ohta
- Department of Microbiology and Immunology, University of Maryland, Baltimore, MD 21201, USA.
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Abstract
PURPOSE OF REVIEW The exploding prevalence of insulin resistance and Type 2 diabetes (T2D) linked to obesity has become an alarming public health concern. Worldwide, approximately 171 million people suffer from obesity-induced diabetes and public health authorities expect this situation to deteriorate rapidly. An interesting clinical population of 'metabolically healthy but obese' (MHO) cases is relatively protected from T2D and its associated cardiovascular risk. The molecular basis for this protection is not well understood but is likely to involve reduced inflammatory responses. The inflammatory cells and pathways that respond to overnutrition are the primary subject matter for this review. RECENT FINDINGS The chance discovery of a genetic mutation in the Brd2 gene, which is located in the class II major histocompatibility complex and makes mice enormously fat but protects them from diabetes, offers revolutionary new insights into the cellular mechanisms that link obesity to insulin resistance and T2D. These Brd2-hypomorphic mice have reduced inflammation in fat that is normally associated with insulin resistance, and resemble MHO patients, suggesting novel therapeutic pathways for obese patients at risk for T2D. SUMMARY Deeper understanding of the functional links between genes that control inflammatory responses to diet-induced obesity is crucial to the development of therapies for obese, insulin-resistant patients.
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Affiliation(s)
- Anna C Belkina
- Boston Nutrition Obesity Research Center, Cancer Research Center, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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Denis GV, Nikolajczyk BS, Schnitzler GR. An emerging role for bromodomain-containing proteins in chromatin regulation and transcriptional control of adipogenesis. FEBS Lett 2010; 584:3260-8. [PMID: 20493850 DOI: 10.1016/j.febslet.2010.05.030] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2010] [Accepted: 05/16/2010] [Indexed: 12/11/2022]
Abstract
Transcriptional co-activators, co-repressors and chromatin remodeling machines are essential elements in the transcriptional programs directed by the master adipogenic transcription factor PPARgamma. Many of these components have orthologs in other organisms, where they play roles in development and pattern formation, suggesting new links between cell fate decision-making and adipogenesis. This review focuses on bromodomain-containing protein complexes recently shown to play a critical role in adipogenesis. Deeper understanding of these pathways is likely to have major impact on treatment of obesity-associated diseases, including metabolic syndrome, cardiovascular disease and Type 2 diabetes. The research effort is urgent because the obesity epidemic is serious; the medical community is ill prepared to cope with the anticipated excess morbidity and mortality associated with diet-induced obesity.
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Affiliation(s)
- Gerald V Denis
- Cancer Research Center, Department of Microbiology, Boston University School of Medicine, Boston, MA 02118, USA.
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Abstract
Certain human subpopulations are metabolically healthy but obese, or metabolically obese but normal weight; such mutations uncouple obesity from glucose intolerance, revealing pathways implicated in Type 2 diabetes. Current searches for relevant genes consume significant effort. We have reported previously a novel double bromodomain protein called Brd2, which is a transcriptional co-activator/co-repressor with SWI/SNF (switch mating type/sucrose non-fermenting)-like functions that regulates chromatin. In the present study, we show that wholebody disruption of Brd2, an unusual MHC gene, causes lifelong severe obesity in mice with pancreatic islet expansion, hyperinsulinaemia, hepatosteatosis and elevated pro-inflammatory cytokines, but, surprisingly, enhanced glucose tolerance, elevated adiponectin, increased weight of brown adipose tissue, heat production and expression of mitochondrial uncoupling proteins in brown adipose tissue, reduced macrophage infiltration in white adipose tissue, and lowered blood glucose, leading to an improved metabolic profile and avoiding eventual Type 2 diabetes. Brd2 is highly expressed in pancreatic beta-cells, where it normally inhibits beta-cell mitosis and insulin transcription. In 3T3-L1 pre-adipocytes, Brd2 normally co-represses PPAR-gamma (peroxisome-proliferator-activated receptor-gamma) and inhibits adipogenesis. Brd2 knockdown protects 3T3-L1 adipocytes from TNF-alpha (tumour necrosis factor-alpha)-induced insulin resistance, thereby decoupling inflammation from insulin resistance. Thus hypomorphic Brd2 shifts energy balance toward storage without causing glucose intolerance and may provide a novel model for obese metabolically healthy humans.
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Vollmuth F, Blankenfeldt W, Geyer M. Structures of the dual bromodomains of the P-TEFb-activating protein Brd4 at atomic resolution. J Biol Chem 2009; 284:36547-36556. [PMID: 19828451 DOI: 10.1074/jbc.m109.033712] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Brd4 is a member of the bromodomains and extra terminal domain (BET) family of proteins that recognize acetylated chromatin structures through their bromodomains and act as transcriptional activators. Brd4 functions as an associated factor and positive regulator of P-TEFb, a Cdk9-cyclin T heterodimer that stimulates transcriptional elongation by RNA polymerase II. Here, the crystal structures of the two bromodomains of Brd4 (BD1 and BD2) were determined at 1.5 and 1.2 A resolution, respectively. Complex formation of BD1 with a histone H3 tail polypeptide encompassing residues 12-19 showed binding of the Nzeta-acetylated lysine 14 to the conserved asparagine 140 of Brd4. In contrast, in BD2 the N-terminal linker sequence was found to interact with the binding site for acetylated lysines of the adjacent molecule to form continuous strings in the crystal lattice. This assembly shows for the first time a different binding ligand than acetylated lysine indicating that also other sequence compositions may be able to form similar interaction networks. Isothermal titration calorimetry revealed best binding of BD1 to H3 and of BD2 to H4 acetylated lysine sequences, suggesting alternating histone recognition specificities. Intriguingly, an acetylated lysine motif from cyclin T1 bound similarly well to BD2. Whereas the structure of Brd2 BD1 suggested its dimer formation, both Brd4 bromodomains appeared monomeric in solution as shown by size exclusion chromatography and mutational analyses.
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Affiliation(s)
- Friederike Vollmuth
- Abteilung Physikalische Biochemie, Max-Planck-Institut für Molekulare Physiologie, Otto-Hahn-Strasse 11, D-44227 Dortmund, Germany
| | - Wulf Blankenfeldt
- Abteilung Physikalische Biochemie, Max-Planck-Institut für Molekulare Physiologie, Otto-Hahn-Strasse 11, D-44227 Dortmund, Germany
| | - Matthias Geyer
- Abteilung Physikalische Biochemie, Max-Planck-Institut für Molekulare Physiologie, Otto-Hahn-Strasse 11, D-44227 Dortmund, Germany.
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