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Jiang X, Wen J, Paver E, Wu Y, Sun G, Bullman A, Dahlstrom J, Tremethick DJ, Soboleva TA. H2A.B is a cancer/testis factor involved in the activation of ribosome biogenesis in Hodgkin lymphoma. EMBO Rep 2021; 22:e52462. [PMID: 34350706 PMCID: PMC8339673 DOI: 10.15252/embr.202152462] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 06/02/2021] [Accepted: 06/15/2021] [Indexed: 12/12/2022] Open
Abstract
Testis-specific regulators of chromatin function are commonly ectopically expressed in human cancers, but their roles are poorly understood. Examination of 81 primary Hodgkin lymphoma (HL) samples showed that the ectopic expression of the eutherian testis-specific histone variant H2A.B is an inherent feature of HL. In experiments using two HL cell lines derived from different subtypes of HL, H2A.B knockdown inhibited cell proliferation. H2A.B was enriched in both nucleoli of these HL cell lines and primary HL samples. We found that H2A.B enhanced ribosomal DNA (rDNA) transcription, was enriched at the rDNA promoter and transcribed regions, and interacted with RNA Pol I. Depletion of H2A.B caused the loss of RNA Pol I from rDNA chromatin. Remarkably, H2A.B was also required for high levels of ribosomal protein gene expression being located at the transcriptional start site and within the gene body. H2A.B knockdown reduced gene body chromatin accessibility of active RNA Pol II genes concurrent with a decrease in transcription. Taken together, our data show that in HL H2A.B has acquired a new function, the ability to increase ribosome biogenesis.
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Affiliation(s)
- Xuanzhao Jiang
- The John Curtin School of Medical ResearchThe Australian National UniversityCanberraACTAustralia
| | - Jiayu Wen
- The John Curtin School of Medical ResearchThe Australian National UniversityCanberraACTAustralia
| | - Elizabeth Paver
- Department of Tissue Pathology and Diagnostic OncologyRoyal Prince Alfred HospitalSydneyNSWAustralia
| | - Yu‐Huan Wu
- The John Curtin School of Medical ResearchThe Australian National UniversityCanberraACTAustralia
- Present address:
IQVIA Solutions Taiwan Ltd.Taipei CityTaiwan
| | - Gege Sun
- The John Curtin School of Medical ResearchThe Australian National UniversityCanberraACTAustralia
- Present address:
Department of Applied Biology and Chemical Technology and State Key Laboratory of Chemical Biology and Drug DiscoveryHong Kong Polytechnic UniversityHong KongChina
| | - Amanda Bullman
- Department of Anatomical PathologyACT PathologyThe Canberra HospitalCanberraACTAustralia
| | - Jane E Dahlstrom
- Department of Anatomical PathologyACT PathologyThe Canberra HospitalCanberraACTAustralia
- Australian National University Medical SchoolThe Australian National UniversityCanberraACTAustralia
| | - David J Tremethick
- The John Curtin School of Medical ResearchThe Australian National UniversityCanberraACTAustralia
| | - Tatiana A Soboleva
- The John Curtin School of Medical ResearchThe Australian National UniversityCanberraACTAustralia
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Salahong T, Schwartz C, Sungthong R. Are BET Inhibitors yet Promising Latency-Reversing Agents for HIV-1 Reactivation in AIDS Therapy? Viruses 2021; 13:v13061026. [PMID: 34072421 PMCID: PMC8228869 DOI: 10.3390/v13061026] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 05/24/2021] [Accepted: 05/26/2021] [Indexed: 12/26/2022] Open
Abstract
AIDS first emerged decades ago; however, its cure, i.e., eliminating all virus sources, is still unachievable. A critical burden of AIDS therapy is the evasive nature of HIV-1 in face of host immune responses, the so-called "latency." Recently, a promising approach, the "Shock and Kill" strategy, was proposed to eliminate latently HIV-1-infected cell reservoirs. The "Shock and Kill" concept involves two crucial steps: HIV-1 reactivation from its latency stage using a latency-reversing agent (LRA) followed by host immune responses to destroy HIV-1-infected cells in combination with reinforced antiretroviral therapy to kill the progeny virus. Hence, a key challenge is to search for optimal LRAs. Looking at epigenetics of HIV-1 infection, researchers proved that some bromodomains and extra-terminal motif protein inhibitors (BETis) are able to reactivate HIV-1 from latency. However, to date, only a few BETis have shown HIV-1-reactivating functions, and none of them have yet been approved for clinical trial. In this review, we aim to demonstrate the epigenetic roles of BETis in HIV-1 infection and HIV-1-related immune responses. Possible future applications of BETis and their HIV-1-reactivating properties are summarized and discussed.
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Affiliation(s)
- Thanarat Salahong
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand;
| | - Christian Schwartz
- Research Unit 7292, DHPI, IUT Louis Pasteur, University of Strasbourg, 67300 Schiltigheim, France
- Correspondence: (C.S.); (R.S.)
| | - Rungroch Sungthong
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow G61 1QH, UK
- Laboratory of Hydrology and Geochemistry of Strasbourg, University of Strasbourg, UMR 7517 CNRS/EOST, 67084 Strasbourg CEDEX, France
- Correspondence: (C.S.); (R.S.)
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BRDT promotes ovarian cancer cell growth. Cell Death Dis 2020; 11:1021. [PMID: 33257688 PMCID: PMC7705741 DOI: 10.1038/s41419-020-03225-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 10/29/2020] [Accepted: 10/30/2020] [Indexed: 12/18/2022]
Abstract
Bromodomain testis-specific factor (BRDT) is a member of the bromodomain and extra-terminal (BET) family proteins. Its expression and potential functions in ovarian cancer were examined. We show that BRDT is overexpressed in human ovarian cancer tissues and in established (CaOV3)/primary ovarian cancer cells. However, its expression is low in ovarian epithelial tissues and cells. Significantly, shRNA-induced silencing or CRISPR/Cas9-mediated knockout of BRDT inhibited ovarian cancer cell growth, viability, proliferation and migration, and induced significant apoptosis activation. Conversely, exogenous overexpression of BRDT, by a lentiviral construct, augmented CaOV3 cell proliferation and migration. In CaOV3 cells expression of two key BRDT target genes, polo-like kinase 1 (PLK1) and aurora kinase C (AURKC), was downregulated by BRDT shRNA or knockout, but upregulated with BRDT overexpression. In vivo, xenograft tumors-derived from BRDT-knockout CaOV3 cells grew significantly slower than control tumors in severe combined immunodeficient (SCID) mice. Furthermore, intratumoral injection of BRDT shRNA lentivirus potently inhibited the growth of primary ovarian cancer xenografts in SCID mice. Downregulation of PLK1 and AURKC was detected in BRDT-knockout and BRDT-silenced tumor tissues. Collectively, BRDT overexpression promotes ovarian cancer cell progression. Targeting BRDT could be a novel strategy to treat ovarian cancer.
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Wan P, Chen Z, Zhong W, Jiang H, Huang Z, Peng D, He Q, Chen N. BRDT is a novel regulator of eIF4EBP1 in renal cell carcinoma. Oncol Rep 2020; 44:2475-2486. [PMID: 33125143 PMCID: PMC7610328 DOI: 10.3892/or.2020.7796] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 08/24/2020] [Indexed: 12/20/2022] Open
Abstract
Among all types of kidney diseases, renal cell carcinoma (RCC) has the highest mortality, recurrence and metastasis rates, which results in high numbers of tumor-associated mortalities in China. Identifying a novel therapeutic target has attracted increasing attention. Bromodomain and extraterminal domain (BET) proteins have the ability to read the epigenome, leading to regulation of gene transcription. As an important member of the BET family, bromodomain testis-specific protein (BRDT) has been well studied; however, the mechanism underlying BRDT in the regulation of RCC has not been fully investigated. Eukaryotic translation initiation factor 4E-binding protein 1 (eIF4EBP1) is a binding partner of eIF4E that is involved in affecting the progression of various cancer types via regulating gene transcription. To identify novel regulators of eIF4EBP1, an immunoprecipitation assay and mass spectrometry analysis was performed in RCC cells. It was revealed that eIF4EBP1 interacted with BRDT, a novel interacting protein. In addition, the present study further demonstrated that BRDT inhibitors PLX51107 and INCB054329 blocked the progression of RCC cells, along with suppressing eIF4EBP1 and c-myc expression. Small interfering (si) RNAs were used to knock down BRDT expression, which suppressed RCC cell proliferation and eIF4EBP1 protein expression. In addition, overexpression of eIF4EBP1 partially abolished the inhibited growth function of PLX51107 but knocking down eIF4EBP1 improved the inhibitory effects of PLX51107. Furthermore, treatment with PLX51107 or knockdown of BRDT expression decreased c-myc expression at both the mRNA and protein levels, and attenuated its promoter activity, as determined by luciferase reporter assays. PLX51107 also significantly altered the interaction between the c-myc promoter with eIF4EBP1 and significantly attenuated the increase of RCC tumors, accompanied by decreased c-myc mRNA and protein levels in vivo. Taken together, these data suggested that blocking of BRDT by PLX51107, INCB054329 or BRDT knockdown suppressed the growth of RCC via decreasing eIF4EBP1, thereby leading to decreased c-myc transcription levels. Considering the regulatory function of BET proteins in gene transcription, the present study suggested that there is a novel mechanism underlying eIF4EBP1 regulation by BRDT, and subsequently decreased c-myc in RCC, and further identified a new approach by regulating eIF4EBP1 or c-myc for enhancing BRDT-targeting RCC therapy.
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Affiliation(s)
- Pei Wan
- Meizhou People's Hospital (Huangtang Hospital), Meizhou, Guangdong 514031, P.R. China
| | - Zhilin Chen
- Meizhou People's Hospital (Huangtang Hospital), Meizhou, Guangdong 514031, P.R. China
| | - Weifeng Zhong
- Meizhou People's Hospital (Huangtang Hospital), Meizhou, Guangdong 514031, P.R. China
| | - Huiming Jiang
- Meizhou People's Hospital (Huangtang Hospital), Meizhou, Guangdong 514031, P.R. China
| | - Zhicheng Huang
- Meizhou People's Hospital (Huangtang Hospital), Meizhou, Guangdong 514031, P.R. China
| | - Dong Peng
- Meizhou People's Hospital (Huangtang Hospital), Meizhou, Guangdong 514031, P.R. China
| | - Qiang He
- Meizhou People's Hospital (Huangtang Hospital), Meizhou, Guangdong 514031, P.R. China
| | - Nanhui Chen
- Meizhou People's Hospital (Huangtang Hospital), Meizhou, Guangdong 514031, P.R. China
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Wang LF, Wang Y, Yang ZY, Zhao J, Sun HB, Wu SL. Revealing binding selectivity of inhibitors toward bromodomain-containing proteins 2 and 4 using multiple short molecular dynamics simulations and free energy analyses. SAR AND QSAR IN ENVIRONMENTAL RESEARCH 2020; 31:373-398. [PMID: 32496901 DOI: 10.1080/1062936x.2020.1748107] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 03/24/2020] [Indexed: 06/11/2023]
Abstract
Emerging evidences indicate bromodomain-containing proteins 2 and 4 (BRD2 and BRD4) play critical roles in cancers, inflammations, cardiovascular diseases and other pathologies. Multiple short molecular dynamics (MSMD) simulations combined with molecular mechanics generalized Born surface area (MM-GBSA) method were applied to investigate the binding selectivity of three inhibitors 87D, 88M and 89G towards BRD2 over BRD4. The root-mean-square fluctuation (RMSF) analysis indicates that the structural flexibility of BRD4 is stronger than that of BRD2. Moreover the calculated distances between the Cα atoms in the centres of the ZA_loop and BC_loop of BRD4 are also bigger than that of BRD2. The rank of binding free energies calculated using MM-GBSA method agrees well with that determined by experimental data. The results show that 87D can bind more favourably to BRD2 than BRD4, while 88M has better selectivity on BRD4 over BRD2. Residue-based free-energy decomposition method was utilized to estimate the inhibitor-residue interaction spectrum and the results not only identify the hot interaction spots of inhibitors with BRD2 and BRD4, but also demonstrate that several common residues, including (W370, W374), (P371, P375), (V376, V380) and (L381, L385) belonging to (BRD2, BRD4), generate significant binding difference of inhibitors to BRD2 and BRD4.
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Affiliation(s)
- L F Wang
- School of Science, Shandong Jiaotong University , Jinan, China
| | - Y Wang
- School of Science, Shandong Jiaotong University , Jinan, China
| | - Z Y Yang
- Department of Physics, Jiangxi Agricultural University , Nanchang, China
| | - J Zhao
- School of Science, Shandong Jiaotong University , Jinan, China
| | - H B Sun
- School of Science, Shandong Jiaotong University , Jinan, China
| | - S L Wu
- School of Science, Shandong Jiaotong University , Jinan, China
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Del Gaudio N, Di Costanzo A, Liu NQ, Conte L, Migliaccio A, Vermeulen M, Martens JHA, Stunnenberg HG, Nebbioso A, Altucci L. BRD9 binds cell type-specific chromatin regions regulating leukemic cell survival via STAT5 inhibition. Cell Death Dis 2019; 10:338. [PMID: 31000698 PMCID: PMC6472371 DOI: 10.1038/s41419-019-1570-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 03/21/2019] [Accepted: 04/04/2019] [Indexed: 02/07/2023]
Abstract
Leukemia is characterized by genetic and epigenetic mutations resulting in selection of cancer cells, which are unable to differentiate. Although genetic alterations are difficult to target, the epigenome is intrinsically dynamic and readily offers new therapeutic strategies. Thus, identifying cancer-specific context-dependent targets and unraveling their biological function may open up new therapeutic perspectives. Here we identify bromodomain-containing protein 9 (BRD9) as a critical target required in acute myeloid leukemia (AML). We show that BRD9 is overexpressed in AML cells including ex vivo primary blasts compared with CD34+ cells. By targeting BRD9 expression in AML, we observed an alteration in proliferation and survival, ultimately resulting in the induction of apoptosis. Intriguingly, genome-wide profiling revealed that BRD9 binds enhancer regions in a cell type-specific manner, regulating cell type-related processes. We unveil a novel BRD9-sustained STAT5 pathway activation via regulation of SOCS3 expression levels. Our findings identify a previously undescribed BRD9-STAT5 axis as critical for leukemia maintenance, suggesting BRD9 as a potential therapeutic target.
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Affiliation(s)
- Nunzio Del Gaudio
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Vico L. De Crecchio 7, 80138, Napoli, Italy.
| | - Antonella Di Costanzo
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Vico L. De Crecchio 7, 80138, Napoli, Italy
| | - Ning Qing Liu
- Division Gene Regulation, Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
| | - Lidio Conte
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Vico L. De Crecchio 7, 80138, Napoli, Italy
| | - Antimo Migliaccio
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Vico L. De Crecchio 7, 80138, Napoli, Italy
| | - Michiel Vermeulen
- Department of Molecular Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Oncode Institute, Radboud University, 6525 GA, Nijmegen, The Netherlands
| | - Joost H A Martens
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Vico L. De Crecchio 7, 80138, Napoli, Italy.,Department of Molecular Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Oncode Institute, Radboud University, 6525 GA, Nijmegen, The Netherlands
| | - Hendrik G Stunnenberg
- Department of Molecular Biology, Faculty of Science, Radboud Institute for Molecular Life Sciences, Oncode Institute, Radboud University, 6525 GA, Nijmegen, The Netherlands
| | - Angela Nebbioso
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Vico L. De Crecchio 7, 80138, Napoli, Italy
| | - Lucia Altucci
- Department of Precision Medicine, University of Campania "Luigi Vanvitelli", Vico L. De Crecchio 7, 80138, Napoli, Italy.
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