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Malachowski T, Chandradoss KR, Boya R, Zhou L, Cook AL, Su C, Pham K, Haws SA, Kim JH, Ryu HS, Ge C, Luppino JM, Nguyen SC, Titus KR, Gong W, Wallace O, Joyce EF, Wu H, Rojas LA, Phillips-Cremins JE. Spatially coordinated heterochromatinization of long synaptic genes in fragile X syndrome. Cell 2023; 186:5840-5858.e36. [PMID: 38134876 PMCID: PMC10794044 DOI: 10.1016/j.cell.2023.11.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 07/31/2023] [Accepted: 11/16/2023] [Indexed: 12/24/2023]
Abstract
Short tandem repeat (STR) instability causes transcriptional silencing in several repeat expansion disorders. In fragile X syndrome (FXS), mutation-length expansion of a CGG STR represses FMR1 via local DNA methylation. Here, we find megabase-scale H3K9me3 domains on autosomes and encompassing FMR1 on the X chromosome in FXS patient-derived iPSCs, iPSC-derived neural progenitors, EBV-transformed lymphoblasts, and brain tissue with mutation-length CGG expansion. H3K9me3 domains connect via inter-chromosomal interactions and demarcate severe misfolding of TADs and loops. They harbor long synaptic genes replicating at the end of S phase, replication-stress-induced double-strand breaks, and STRs prone to stepwise somatic instability. CRISPR engineering of the mutation-length CGG to premutation length reverses H3K9me3 on the X chromosome and multiple autosomes, refolds TADs, and restores gene expression. H3K9me3 domains can also arise in normal-length iPSCs created with perturbations linked to genome instability, suggesting their relevance beyond FXS. Our results reveal Mb-scale heterochromatinization and trans interactions among loci susceptible to instability.
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Affiliation(s)
- Thomas Malachowski
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Keerthivasan Raanin Chandradoss
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Ravi Boya
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Linda Zhou
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Ashley L Cook
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Chuanbin Su
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Kenneth Pham
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Spencer A Haws
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Ji Hun Kim
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Han-Seul Ryu
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Chunmin Ge
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Jennifer M Luppino
- Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Son C Nguyen
- Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Katelyn R Titus
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Wanfeng Gong
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Owen Wallace
- Fulcrum Therapeutics Incorporated, Cambridge, MA, USA
| | - Eric F Joyce
- Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA
| | - Hao Wu
- Fulcrum Therapeutics Incorporated, Cambridge, MA, USA
| | | | - Jennifer E Phillips-Cremins
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Epigenetics Institute, University of Pennsylvania, Philadelphia, PA, USA; Department of Genetics, University of Pennsylvania, Philadelphia, PA, USA.
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2
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Fang Y, Zhang MC, He Y, Li C, Fang H, Xu PP, Cheng S, Zhao Y, Feng Y, Liu Q, Wang L, Zhao WL. Human endogenous retroviruses as epigenetic therapeutic targets in TP53-mutated diffuse large B-cell lymphoma. Signal Transduct Target Ther 2023; 8:381. [PMID: 37798292 PMCID: PMC10556001 DOI: 10.1038/s41392-023-01626-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 08/13/2023] [Accepted: 08/21/2023] [Indexed: 10/07/2023] Open
Abstract
TP53 mutation (TP53mut) occurs in 10-20% of diffuse large B-cell lymphoma (DLBCL) cases and serves as an unfavorable biomarker of DLBCL progression. It confers resistance to immunochemotherapy, high-dose chemotherapy, autologous stem cell transplantation, and anti-CD19 chimeric antigen receptor T-cell therapy. Therapeutic targeting of TP53mut remains a significant challenge in DLBCL treatment. Here we assessed TP53mut in 667 patients with newly diagnosed DLBCL, including 576 patients treated with immunochemotherapy rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) and 91 patients with decitabine plus R-CHOP (DR-CHOP, NCT02951728 and NCT04025593). TP53mut independently predicted an inferior prognosis in R-CHOP-treated DLBCL, although this could be mitigated by DR-CHOP treatment. In TP53mut patients, multiple viral regulation pathways were repressed, resulting in the inhibition of immune modulation, as revealed by gene set enrichment analysis. TP53mut DLBCL exhibited increased methyltransferase SUV39H1 expression and H3K9 trimethylation (H3K9me3), contributing to repression of endogenous retroviruses (ERVs) and immunosuppressive tumor microenvironment. In TP53mut DLBCL cell lines, decitabine down-regulated SUV39H1, inhibited H3K9me3 occupancy on ERVs, and triggered ERV expression, thereby unleashing interferons program and CD4+T/CD8+T cell activation. Molecular silencing of SUV39H1 significantly abrogated decitabine-induced H3K9me3 inhibition and ERV expression. In TP53mut patient-derived xenograft models and TP53mut patients, the anti-tumor effect was improved upon the use of combined treatment of decitabine and doxorubicin via SUV39H1-H3K9me3-ERVs axis. Collectively, our findings highlight an ERV regulatory circuitry in TP53mut DLBCL and the crucial roles ERVs for epigenetically reprogramming tumor microenvironment for treating TP53mut-driven cancers.
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Grants
- National Key R&D Program of China (2022YFC2502600), Chang Jiang Scholars Program, Shanghai Commission of Science and Technology (17PJ1405800), Shanghai Municipal Education Commission Gaofeng Clinical Medicine Grant Support (20152206, 20152208, and 20171902), Clinical Research Plan of Shanghai hospital development center (SHDC, 2020CR1032B), Multicenter Clinical Research Project by Shanghai Jiao Tong University School of Medicine (DLY201601), Samuel Waxman Cancer Research Foundation, and the Foundation of National Facility for Translational Medicine (Shanghai, TMSK-2020-115).
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Affiliation(s)
- Ying Fang
- Shanghai Institute of Hematology, State Key Laboratory of Medical Genomics, National Research Center for Translational Medicine at Shanghai, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Mu-Chen Zhang
- Shanghai Institute of Hematology, State Key Laboratory of Medical Genomics, National Research Center for Translational Medicine at Shanghai, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yang He
- Shanghai Institute of Hematology, State Key Laboratory of Medical Genomics, National Research Center for Translational Medicine at Shanghai, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chen Li
- Network and Information Center, Shanghai Jiao Tong University, Shanghai, China
| | - Hai Fang
- Shanghai Institute of Hematology, State Key Laboratory of Medical Genomics, National Research Center for Translational Medicine at Shanghai, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Peng-Peng Xu
- Shanghai Institute of Hematology, State Key Laboratory of Medical Genomics, National Research Center for Translational Medicine at Shanghai, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shu Cheng
- Shanghai Institute of Hematology, State Key Laboratory of Medical Genomics, National Research Center for Translational Medicine at Shanghai, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yan Zhao
- Shanghai Institute of Hematology, State Key Laboratory of Medical Genomics, National Research Center for Translational Medicine at Shanghai, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yan Feng
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Qian Liu
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Li Wang
- Shanghai Institute of Hematology, State Key Laboratory of Medical Genomics, National Research Center for Translational Medicine at Shanghai, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Wei-Li Zhao
- Shanghai Institute of Hematology, State Key Laboratory of Medical Genomics, National Research Center for Translational Medicine at Shanghai, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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Karttunen K, Patel D, Xia J, Fei L, Palin K, Aaltonen L, Sahu B. Transposable elements as tissue-specific enhancers in cancers of endodermal lineage. Nat Commun 2023; 14:5313. [PMID: 37658059 PMCID: PMC10474299 DOI: 10.1038/s41467-023-41081-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 08/23/2023] [Indexed: 09/03/2023] Open
Abstract
Transposable elements (TE) are repetitive genomic elements that harbor binding sites for human transcription factors (TF). A regulatory role for TEs has been suggested in embryonal development and diseases such as cancer but systematic investigation of their functions has been limited by their widespread silencing in the genome. Here, we utilize unbiased massively parallel reporter assay data using a whole human genome library to identify TEs with functional enhancer activity in two human cancer types of endodermal lineage, colorectal and liver cancers. We show that the identified TE enhancers are characterized by genomic features associated with active enhancers, such as epigenetic marks and TF binding. Importantly, we identify distinct TE subfamilies that function as tissue-specific enhancers, namely MER11- and LTR12-elements in colon and liver cancers, respectively. These elements are bound by distinct TFs in each cell type, and they have predicted associations to differentially expressed genes. In conclusion, these data demonstrate how different cancer types can utilize distinct TEs as tissue-specific enhancers, paving the way for comprehensive understanding of the role of TEs as bona fide enhancers in the cancer genomes.
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Affiliation(s)
- Konsta Karttunen
- Applied Tumor Genomics Program, Research Programs Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Divyesh Patel
- Applied Tumor Genomics Program, Research Programs Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- iCAN Digital Precision Cancer Medicine Flagship, University of Helsinki, Helsinki, Finland
| | - Jihan Xia
- Applied Tumor Genomics Program, Research Programs Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- iCAN Digital Precision Cancer Medicine Flagship, University of Helsinki, Helsinki, Finland
| | - Liangru Fei
- Applied Tumor Genomics Program, Research Programs Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Kimmo Palin
- Applied Tumor Genomics Program, Research Programs Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- iCAN Digital Precision Cancer Medicine Flagship, University of Helsinki, Helsinki, Finland
| | - Lauri Aaltonen
- Applied Tumor Genomics Program, Research Programs Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- iCAN Digital Precision Cancer Medicine Flagship, University of Helsinki, Helsinki, Finland
| | - Biswajyoti Sahu
- Applied Tumor Genomics Program, Research Programs Unit, Faculty of Medicine, University of Helsinki, Helsinki, Finland.
- iCAN Digital Precision Cancer Medicine Flagship, University of Helsinki, Helsinki, Finland.
- Medicum, Faculty of Medicine, University of Helsinki, Helsinki, Finland.
- Centre for Molecular Medicine Norway, University of Oslo, Oslo, Norway.
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Saha G, Roy S, Basu M, Ghosh MK. USP7 - a crucial regulator of cancer hallmarks. Biochim Biophys Acta Rev Cancer 2023; 1878:188903. [PMID: 37127084 DOI: 10.1016/j.bbcan.2023.188903] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 04/28/2023] [Accepted: 04/28/2023] [Indexed: 05/03/2023]
Abstract
Over the course of three decades of study, the deubiquitinase Herpesvirus associated Ubiquitin-Specific Protease/Ubiquitin-Specific Protease 7 (HAUSP/USP7) has gradually come to be recognized as a crucially important molecule in cellular physiology. The fact that USP7 is overexpressed in a number of cancers, including breast, prostate, colorectal, and lung cancers, supports the idea that USP7 is also an important regulator of tumorigenesis. In this review, we discuss USP7's function in relation to the cancer hallmarks described by Hanahan and Weinberg. This post-translational modifier can support increased proliferation, block unfavorable growth signals, stop cell death, and support an unstable cellular genome by manipulating key players in the pertinent signalling circuit. It is interesting to note that USP7 also aids in the stabilization of molecules that support angiogenesis and metastasis. Targeting USP7 has now emerged as a crucial component of USP7 research because pharmacological inhibition of USP7 supports p53-mediated cell cycle arrest and apoptosis. Efficacious USP7 inhibition is currently being investigated in both synthetic and natural compounds, but issues with selectivity and a lack of co-crystal structure have hindered USP7 inhibition from being tested in clinical settings. Moreover, the development of new, more effective USP7 inhibitors and their encouraging implications by numerous groups give us a glimmer of hope for USP7-targeting medications as effective substitutes for hazardous cancer chemotherapeutics.
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Affiliation(s)
- Gouranga Saha
- Cancer Biology and Inflammatory Disorder Division, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology (CSIR-IICB), TRUE Campus, CN-6, Sector-V, Salt Lake, Kolkata-700091 & 4, Raja S.C. Mullick Road, Jadavpur, Kolkata, PIN - 700032, India
| | - Srija Roy
- Cancer Biology and Inflammatory Disorder Division, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology (CSIR-IICB), TRUE Campus, CN-6, Sector-V, Salt Lake, Kolkata-700091 & 4, Raja S.C. Mullick Road, Jadavpur, Kolkata, PIN - 700032, India
| | - Malini Basu
- Department of Microbiology, Dhruba Chand Halder College, University of Calcutta, Kolkata, PIN - 743372, India
| | - Mrinal K Ghosh
- Cancer Biology and Inflammatory Disorder Division, Council of Scientific and Industrial Research-Indian Institute of Chemical Biology (CSIR-IICB), TRUE Campus, CN-6, Sector-V, Salt Lake, Kolkata-700091 & 4, Raja S.C. Mullick Road, Jadavpur, Kolkata, PIN - 700032, India.
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Transcription analysis of a histones modifiers panel coupled with critical tumor suppressor genes displayed frequent changes in patients with AML.: mRNA levels of histones modifiers and TSGs in AML. Curr Res Transl Med 2021; 69:103311. [PMID: 34455155 DOI: 10.1016/j.retram.2021.103311] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 08/02/2021] [Accepted: 08/17/2021] [Indexed: 02/08/2023]
Abstract
Epigenetic alterations could cause leukemia through the activation of normally silent loci or silencing of normally active loci. We herein aimed to compare the expression patterns of a histone modifiers panel consisted of SUV39H1, PRDM16, UHRF2, KDM2B, and KDM3C between acute myeloid leukemia(AML) cells and normal cells and to assess the correlation of these genes with the expression of vital tumor suppressor genes, including p16INK4A and p53. Bone marrow or peripheral blood samples of 50 AML patients at diagnosis and also 18 subjects with a normal hematopoietic system as a control group were obtained after informed consent. Then, qRT-PCR was performed to determine the expression levels of the aforementioned genes. We found a broad alteration in the expression signature of five out of seven studied genes in AML patients as compared with the control group. UHRF2 and p53 were remarkably downregulated in AML patients (P<0.001), while SUV39H1, PRDM16, and KDM3C were significantly overexpressed (P<0.01). Based on the Spearman rank correlation, SUV39H1 and KDM2B negatively regulated both p16INK4A and p53 expression. Taken together, our findings provided preliminary evidence regarding the pervasive mRNA perturbation of histone modifiers and their plausible influences on critical tumor suppressor genes. Future studies in this area would be required to assist in establishing these results in the clinical practice of AML patients.
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Zhou Z, Zheng X, Mei X, Li W, Qi S, Deng Y, Lei B. Hsa_circ_0080229 upregulates the expression of murine double minute-2 (MDM2) and promotes glioma tumorigenesis and invasion via the miR-1827 sponging mechanism. ANNALS OF TRANSLATIONAL MEDICINE 2021; 9:762. [PMID: 34268375 PMCID: PMC8246201 DOI: 10.21037/atm-20-7123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 02/21/2021] [Indexed: 12/17/2022]
Abstract
Background Glioma is the most common and fatal primary cranial tumor. The epidermal growth factor receptor (EGFR) plays an important role in the occurrence and treatment of glioma, which might function through a circular ribonucleic acid (circRNA)-related mechanism. Hsa_circ_0080229 (circ_0080229) has been identified as a circRNA arising from an EGFR gene in gliomas; however, little is known about its molecular mechanism to date. Methods To address this question, a series of experiments were conducted to confirm the effect of circ_0080229 in gliomas and identify the downstream mechanism. A quantitative real-time polymerase chain reaction (qRT-PCR) analysis and in-situ hybridization/fluorescence in-situ hybridization (ISH/FISH) testing were performed to identify the expression of circ_0080229 in patient samples. Bioinformatic analysis was carried out to explore the possible mechanism. Next, a series of in-vitro functional assays and in-vivo assays with a xenograft subcutaneous glioma model was carried out to confirm the effect of circ_0080229. Finally, qRT-PCR analysis and a Western Blot analysis were performed to verify the related mechanism. Results The expression of circ_0080229 was upregulated in both glioma tissues and cell lines related to unfavorable clinicopathologic characteristics. The expression of circ_0080229 was found to be inversely correlated with miR-1827, a micro-ribonucleic acid (miRNA) targeting murine double minute-2 (MDM2). The downregulation of circ_0080229 inhibited gliomas in vivo and suppressed U87 and U251 cell lines in vitro, which the transfection of the miR-1827 inhibitor could reverse. Concerning the mechanism, a block of circ_0080229 decreased MDM2 expression, while the inhibition of miR-1827 reversed this effect. Thus, circ_0080229 appears to target the downstream miR-1827/MDM2 signaling pathway. Conclusions Our results showed that the silencing of circ_0080229 upregulates the expression of miR-1827, which in turn resulted in the suppression of MDM2, and the mediation of the downstream P53 signaling pathway. Circ_0080229 exerted an effect in mediating tumor progression through the MDM2 signaling pathway by sponging miR-1827. Its importance as a potential prognostic biomarker in gliomas has thus been established.
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Affiliation(s)
- Zhiwei Zhou
- Department of Neurosurgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Faculty of Health Sciences, University of Macau, Taipa, Macau, China
| | - Xiuyuan Zheng
- Department of Rehabilitation Medicine, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Xin Mei
- Department of Neurosurgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Wengpeng Li
- Department of Neurosurgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Songtao Qi
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yuefei Deng
- Department of Neurosurgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China
| | - Bingxi Lei
- Department of Neurosurgery, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China.,Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
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7
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Hanna R, Flamier A, Barabino A, Bernier G. G-quadruplexes originating from evolutionary conserved L1 elements interfere with neuronal gene expression in Alzheimer's disease. Nat Commun 2021; 12:1828. [PMID: 33758195 PMCID: PMC7987966 DOI: 10.1038/s41467-021-22129-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 03/03/2021] [Indexed: 02/06/2023] Open
Abstract
DNA sequences containing consecutive guanines organized in 4-interspaced tandem repeats can form stable single-stranded secondary structures, called G-quadruplexes (G4). Herein, we report that the Polycomb group protein BMI1 is enriched at heterochromatin regions containing putative G4 DNA sequences, and that G4 structures accumulate in cells with reduced BMI1 expression and/or relaxed chromatin, including sporadic Alzheimer's disease (AD) neurons. In AD neurons, G4 structures preferentially accumulate in lamina-associated domains, and this is rescued by re-establishing chromatin compaction. ChIP-seq analyses reveal that G4 peaks correspond to evolutionary conserved Long Interspersed Element-1 (L1) sequences predicted to be transcriptionally active. Hence, G4 structures co-localize with RNAPII, and inhibition of transcription can reverse the G4 phenotype without affecting chromatin's state, thus uncoupling both components. Intragenic G4 structures affecting splicing events are furthermore associated with reduced neuronal gene expression in AD. Active L1 sequences are thus at the origin of most G4 structures observed in human neurons.
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Affiliation(s)
- Roy Hanna
- Stem Cell and Developmental Biology Laboratory, Hôpital Maisonneuve-Rosemont, Montreal, QC, Canada
| | - Anthony Flamier
- Stem Cell and Developmental Biology Laboratory, Hôpital Maisonneuve-Rosemont, Montreal, QC, Canada
- Whitehead Institute of Biomedical Research, Cambridge, MA, USA
| | - Andrea Barabino
- Stem Cell and Developmental Biology Laboratory, Hôpital Maisonneuve-Rosemont, Montreal, QC, Canada
| | - Gilbert Bernier
- Stem Cell and Developmental Biology Laboratory, Hôpital Maisonneuve-Rosemont, Montreal, QC, Canada.
- Department of Neurosciences, University of Montreal, Montreal, QC, Canada.
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8
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Sheikh T, Sen E. p53 affects epigenetic signature on SOCS1 promoter in response to TLR4 inhibition. Cytokine 2021; 140:155418. [PMID: 33476981 DOI: 10.1016/j.cyto.2020.155418] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 12/26/2020] [Indexed: 02/06/2023]
Abstract
Suppressor of cytokine signaling (SOCS1) functions as a negative regulator of toll-like receptor (TLR) induced inflammatory signaling. As silencing of SOCS1 is concomitant with elevated TLR4 levels in glioblastoma, we investigated the effect of TLR4 inhibition on SOCS1 expression. Pharmacological inhibition of TLR4 signaling by TAK242 or its siRNA-mediated knockdown in p53 mutant or wild-type glioma cells resulted in either increased or decreased SOCS1 expression and promoter activity, respectively. Genetic manipulation of p53 indicated that SOCS1 expression upon TLR4 inhibition is dependent on p53 mutational status. Increased SOCS1 level was concomitant with diminished nucleosomal occupancy around p53-binding site on SOCS1 promoter. This altered nucleosomal landscape was accompanied by (i) diminished nuclear H3K9me3 and (ii) increased JMJD2A and Brg1 levels. JMJD2A inhibition or ectopic expression of ATPase-deficient BRG1 prevented TAK242 mediated increase in SOCS1 expression. Recruitment of Brg1-p53-JMJD2A complex on p53 binding sites of SOCS1 promoter upon TLR4 inhibition was concomitant with increased SOCS1 expression in p53-mutant cells. The Cancer Genome Atlas (TCGA) dataset indicated an inverse correlation between TLR4 and SOCS1 levels in p53 mutant but not in p53WT GBM. Taken together, p53 mutational status regulates transcriptional plasticity of SOCS1 promoter through differential recruitment of chromatin remodelers and epigenetic regulators in response to TLR4 inhibition.
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Affiliation(s)
- Touseef Sheikh
- National Brain Research Centre, Manesar, Haryana 122 052, India
| | - Ellora Sen
- National Brain Research Centre, Manesar, Haryana 122 052, India.
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9
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Sandoval JE, Reich NO. p53 and TDG are dominant in regulating the activity of the human de novo DNA methyltransferase DNMT3A on nucleosomes. J Biol Chem 2020; 296:100058. [PMID: 33172892 PMCID: PMC7948466 DOI: 10.1074/jbc.ra120.016125] [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: 09/20/2020] [Revised: 11/03/2020] [Accepted: 11/10/2020] [Indexed: 11/07/2022] Open
Abstract
DNA methylation and histone tail modifications are interrelated mechanisms involved in a wide range of biological processes, and disruption of this crosstalk is linked to diseases such as acute myeloid leukemia. In addition, DNA methyltransferase 3A (DNMT3A) activity is modulated by several regulatory proteins, including p53 and thymine DNA glycosylase (TDG). However, the relative role of histone tails and regulatory proteins in the simultaneous coordination of DNMT3A activity remains obscure. We observed that DNMT3A binds H3 tails and p53 or TDG at distinct allosteric sites to form DNMT3A–H3 tail-p53 or –TDG multiprotein complexes. Functional characterization of DNMT3A–H3 tail-p53 or –TDG complexes on human-derived synthetic histone H3 tails, mononucleosomes, or polynucleosomes shows p53 and TDG play dominant roles in the modulation of DNMT3A activity. Intriguingly, this dominance occurs even when DNMT3A is actively methylating nucleosome substrates. The activity of histone modifiers is influenced by their ability to sense modifications on histone tails within the same nucleosome or histone tails on neighboring nucleosomes. In contrast, we show here that DNMT3A acts on DNA within a single nucleosome, on nucleosomal DNA within adjacent nucleosomes, and DNA not associated with the DNMT3A–nucleosome complex. Our findings have direct bearing on how the histone code drives changes in DNA methylation and highlight the complex interplay between histone tails, epigenetic enzymes, and modulators of enzymatic activity.
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Affiliation(s)
- Jonathan E Sandoval
- Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, California, USA
| | - Norbert O Reich
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California, USA.
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10
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Valles GJ, Bezsonova I, Woodgate R, Ashton NW. USP7 Is a Master Regulator of Genome Stability. Front Cell Dev Biol 2020; 8:717. [PMID: 32850836 PMCID: PMC7419626 DOI: 10.3389/fcell.2020.00717] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 07/13/2020] [Indexed: 12/25/2022] Open
Abstract
Genetic alterations, including DNA mutations and chromosomal abnormalities, are primary drivers of tumor formation and cancer progression. These alterations can endow cells with a selective growth advantage, enabling cancers to evade cell death, proliferation limits, and immune checkpoints, to metastasize throughout the body. Genetic alterations occur due to failures of the genome stability pathways. In many cancers, the rate of alteration is further accelerated by the deregulation of these processes. The deubiquitinating enzyme ubiquitin specific protease 7 (USP7) has recently emerged as a key regulator of ubiquitination in the genome stability pathways. USP7 is also deregulated in many cancer types, where deviances in USP7 protein levels are correlated with cancer progression. In this work, we review the increasingly evident role of USP7 in maintaining genome stability, the links between USP7 deregulation and cancer progression, as well as the rationale of targeting USP7 in cancer therapy.
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Affiliation(s)
- Gabrielle J Valles
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT, United States
| | - Irina Bezsonova
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, CT, United States
| | - Roger Woodgate
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Nicholas W Ashton
- Laboratory of Genomic Integrity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
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11
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Park JW, Bae YS. Dephosphorylation of p53 Ser 392 Enhances Trimethylation of Histone H3 Lys 9 via SUV39h1 Stabilization in CK2 Downregulation-Mediated Senescence. Mol Cells 2019; 42:773-782. [PMID: 31617338 PMCID: PMC6883974 DOI: 10.14348/molcells.2019.0018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 06/24/2019] [Accepted: 09/07/2019] [Indexed: 01/22/2023] Open
Abstract
Cellular senescence is an irreversible form of cell cycle arrest. Senescent cells have a unique gene expression profile that is frequently accompanied by senescence-associated heterochromatic foci (SAHFs). Protein kinase CK2 (CK2) downregulation can induce trimethylation of histone H3 Lys 9 (H3K9me3) and SAHFs formation by activating SUV39h1. Here, we present evidence that the PI3K-AKTmTOR-reactive oxygen species-p53 pathway is necessary for CK2 downregulation-mediated H3K9me3 and SAHFs formation. CK2 downregulation promotes SUV39h1 stability by inhibiting its proteasomal degradation in a p53dependent manner. Moreover, the dephosphorylation status of Ser 392 on p53, a possible CK2 target site, enhances the nuclear import and subsequent stabilization of SUV39h1 by inhibiting the interactions between p53, MDM2, and SUV39h1. Furthermore, p21Cip1/WAF1 is required for CK2 downregulation-mediated H3K9me3, and dephosphorylation of Ser 392 on p53 is important for efficient transcription of p21Cip1/WAF1. Taken together, these results suggest that CK2 downregulation induces dephosphorylation of Ser 392 on p53, which subsequently increases the stability of SUV39h1 and the expression of p21Cip1/WAF1, leading to H3K9me3 and SAHFs formation.
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Affiliation(s)
- Jeong-Woo Park
- School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566,
Korea
| | - Young-Seuk Bae
- School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566,
Korea
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12
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Karsli Uzunbas G, Ahmed F, Sammons MA. Control of p53-dependent transcription and enhancer activity by the p53 family member p63. J Biol Chem 2019; 294:10720-10736. [PMID: 31113863 DOI: 10.1074/jbc.ra119.007965] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 05/15/2019] [Indexed: 01/20/2023] Open
Abstract
Transcriptional activation by p53 provides powerful, organism-wide tumor suppression. We hypothesized that the local chromatin environment, including differential enhancer activities, contributes to various p53-dependent transcriptional activities in different cell types during stress-induced signaling. In this work, using ChIP-sequencing, immunoblotting, quantitative PCR, and computational analyses across various mammalian cell lines, we demonstrate that the p53-induced transcriptome varies by cell type, reflects cell type-specific activities, and is considerably broader than previously anticipated. We found that these molecular events are strongly influenced by p53's engagement with differentially active cell type-specific enhancers and promoters. We also observed that p53 activity depends on the p53 family member tumor protein p63 in epithelial cell types. Notably, we demonstrate that p63 is required for epithelial enhancer identity, including enhancers used by p53 during stress-dependent signaling. Loss of p63, but not p53, caused site-specific depletion of enhancer-associated chromatin modifications, suggesting that p63 functions as an enhancer maintenance factor in epithelial cells. Additionally, a subset of epithelial-specific enhancers depends on the activity of p63 providing a direct link between lineage determination and enhancer structure. These results suggest that a broad, cell-intrinsic mechanism controls p53-dependent cellular stress response through differential regulation of cis-regulatory elements.
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Affiliation(s)
- Gizem Karsli Uzunbas
- From the Department of Biological Sciences, State University of New York at Albany, Albany, New York 12222
| | - Faraz Ahmed
- From the Department of Biological Sciences, State University of New York at Albany, Albany, New York 12222
| | - Morgan A Sammons
- From the Department of Biological Sciences, State University of New York at Albany, Albany, New York 12222
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13
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Li B, Zheng Y, Yang L. The Oncogenic Potential of SUV39H2: A Comprehensive and Perspective View. J Cancer 2019; 10:721-729. [PMID: 30719171 PMCID: PMC6360419 DOI: 10.7150/jca.28254] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 11/09/2018] [Indexed: 02/07/2023] Open
Abstract
Epigenetic modifications at the histone level have attracted significant attention because of their roles in tumorigenesis. Suppressor of variegation 3-9 homolog 2 (SUV39H2, also known as KMT1B) is a member of the SUV39 subfamily of lysine methyltransferases (KMTs) that plays a significant role in histone H3-K9 di-/tri-methylation, transcriptional regulation and cell cycle. Overexpressions of SUV39H2 at gene, mRNA and protein levels are known to be associated with a range of cancers: leukemia, lymphomas, lung cancer, breast cancer, colorectal cancer, gastric cancer, hepatocellular cancer and so on. Accumulating evidence indicates that SUV39H2 acts as an oncogene and contributes to the initiation and progression of cancers. It could, therefore, be a promising target for anti-cancer treatment. In this review, we focus on the dysregulation of SUV39H2 in cancers, including its clinical prognostic predictor role, molecular mechanism involved in cancer occurrence and development, relevant inhibitors against cancer, and its epigenetic modification interaction with immunotherapy. A better understanding of the SUV39H2 will be beneficial to the development of molecular-targeted therapies in cancer.
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Affiliation(s)
- Baihui Li
- Department of Immunology, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China.,National Clinical Research Center for Cancer, Tianjin, China.,Key Laboratory of Cancer Prevention and Therapy, Tianjin, China.,Tianjin's Clinical Research Center for Cancer, Tianjin, China.,Key Laboratory of Cancer Immunology and Biotherapy, Tianjin, China
| | - Yu Zheng
- Department of Immunology, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China.,National Clinical Research Center for Cancer, Tianjin, China.,Key Laboratory of Cancer Prevention and Therapy, Tianjin, China.,Tianjin's Clinical Research Center for Cancer, Tianjin, China.,Key Laboratory of Cancer Immunology and Biotherapy, Tianjin, China
| | - Lili Yang
- Department of Immunology, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China.,National Clinical Research Center for Cancer, Tianjin, China.,Key Laboratory of Cancer Prevention and Therapy, Tianjin, China.,Tianjin's Clinical Research Center for Cancer, Tianjin, China.,Key Laboratory of Cancer Immunology and Biotherapy, Tianjin, China
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14
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A regulatory circuitry comprising TP53, miR-29 family, and SETDB1 in non-small cell lung cancer. Biosci Rep 2018; 38:BSR20180678. [PMID: 30054425 PMCID: PMC6137244 DOI: 10.1042/bsr20180678] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 07/18/2018] [Accepted: 07/20/2018] [Indexed: 12/30/2022] Open
Abstract
Lung cancer is a malignant tumor with high fatality rate and causes great harm to human economic life. Non-small cell lung cancer (NSCLC) is the most common type of lung cancer. With the rapid development of epigenetic study in the last decade, the understanding of the pathogenesis of lung cancer and the development of personalized treatment of lung cancer are picking up pace. Previous studies showed that miR-29 family members (miR-29s; miR-29a, -29b, and -29c) are down-regulated in most human cancers, including NSCLC, but their biological roles in tumorigenesis and their regulation mechanism are still not fully elucidated. Herein, we reported that the miR-29a, -29b and, -29c were coincidently down-regulated in NSCLC, and the histone H3K9 methyltransferase SET domain, bifurcated 1 (SETDB1) was directly targetted by miR-29s. Moreover, SETDB1 negatively regulated the expression of TP53 and overexpression of SETDB1 down-regulating the expression of miR-29s, while TP53 positively regulated the expression of miR-29s and overexpression of TP53 down-regulated the expression of SETDB1. On the other side, as a downstream target of TP53, the H3K9 methyltransferase Suv39h1 was also down-regulated by miR-29s via up-regulating TP53 expression. The further detection of H3K9 methylation status after changes in miR-29s expression revealed that they negatively regulated the levels of H3K9 di- and trimethylation in NSCLC. Collectively, our findings highlight a TP53/miR-29s/SETDB1 regulatory circuitry and assign a role of H3K9 methylation regulator to miR-29s, which may be a potential therapeutic target in the treatment of NSCLC.
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15
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Heterochromatin protects retinal pigment epithelium cells from oxidative damage by silencing p53 target genes. Proc Natl Acad Sci U S A 2018; 115:E3987-E3995. [PMID: 29622681 PMCID: PMC5924883 DOI: 10.1073/pnas.1715237115] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Oxidative stress (OS)-induced retinal pigment epithelium (RPE) cell apoptosis is critically implicated in the pathogenesis of age-related macular degeneration (AMD), a leading cause of blindness in the elderly. Heterochromatin, a compact and transcriptional inert chromatin structure, has been recently shown to be dynamically regulated in response to stress stimuli. The functional mechanism of heterochromatin on OS exposure is unclear, however. Here we show that OS increases heterochromatin formation both in vivo and in vitro, which is essential for protecting RPE cells from oxidative damage. Mechanistically, OS-induced heterochromatin selectively accumulates at p53-regulated proapoptotic target promoters and inhibits their transcription. Furthermore, OS-induced desumoylation of p53 promotes p53-heterochromatin interaction and regulates p53 promoter selection, resulting in the locus-specific recruitment of heterochromatin and transcription repression. Together, our findings demonstrate a protective function of OS-induced heterochromatin formation in which p53 desumoylation-guided promoter selection and subsequent heterochromatin recruitment play a critical role. We propose that targeting heterochromatin provides a plausible therapeutic strategy for the treatment of AMD.
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16
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Sidler C, Kovalchuk O, Kovalchuk I. Epigenetic Regulation of Cellular Senescence and Aging. Front Genet 2017; 8:138. [PMID: 29018479 PMCID: PMC5622920 DOI: 10.3389/fgene.2017.00138] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Accepted: 09/14/2017] [Indexed: 01/05/2023] Open
Abstract
Aging is characterized by functional decline of diverse organs and an increased risk for several diseases. Therefore, a high interest exists in understanding the molecular mechanisms that stimulate aging at all levels, from cells and tissues to organs and organisms, in order to develop ways to promote healthy aging. While many molecular and biochemical mechanisms are already understood in some detail, the role of changes in epigenetic regulation has only begun to be considered in recent years. The age-dependent global reduction in heterochromatin, along with site-specific changes in the patterns of DNA methylation and modification of histones, have been observed in several aging model systems. However, understanding of the precise role of such changes requires further research. In this review, we will discuss the role of epigenetic regulation in aging and indicate future research directions that will help elucidate the mechanistic details of it.
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Affiliation(s)
- Corinne Sidler
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB, Canada
| | - Olga Kovalchuk
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB, Canada
| | - Igor Kovalchuk
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB, Canada
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17
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Wienken M, Moll UM, Dobbelstein M. Mdm2 as a chromatin modifier. J Mol Cell Biol 2017; 9:74-80. [PMID: 27927750 PMCID: PMC5439376 DOI: 10.1093/jmcb/mjw046] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Accepted: 10/30/2016] [Indexed: 12/21/2022] Open
Abstract
Mdm2 is the key negative regulator of the tumour suppressor p53, making it an attractive target for anti-cancer drug design. We recently identified a new role of Mdm2 in gene repression through its direct interaction with several proteins of the polycomb group (PcG) family. PcG proteins form polycomb repressive complexes PRC1 and PRC2. PRC2 (via EZH2) mediates histone 3 lysine 27 (H3K27) trimethylation, and PRC1 (via RING1B) mediates histone 2A lysine 119 (H2AK119) monoubiquitination. Both PRCs mostly support a compact and transcriptionally silent chromatin structure. We found that Mdm2 regulates a gene expression profile similar to that of PRC2 independent of p53. Moreover, Mdm2 promotes the stemness of murine induced pluripotent stem cells and human mesenchymal stem cells, and supports the survival of tumour cells. Mdm2 is recruited to target gene promoters by the PRC2 member and histone methyltransferase EZH2, and enhances PRC-dependent repressive chromatin modifications, specifically H3K27me3 and H2AK119ub1. Mdm2 also cooperates in gene repression with the PRC1 protein RING1B, a H2AK119 ubiquitin ligase. Here we discuss the possible implications of these p53-independent functions of Mdm2 in chromatin dynamics and in the stem cell phenotype. We propose that the p53-independent functions of Mdm2 should be taken into account for cancer drug design. So far, the majority of clinically tested Mdm2 inhibitors target its binding to p53 but do not affect the new functions of Mdm2 described here. However, when targeting the E3 ligase activity of Mdm2, a broader spectrum of its oncogenic activities might become druggable.
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Affiliation(s)
- Magdalena Wienken
- Institute of Molecular Oncology, Göttingen Center for Molecular Biosciences (GZMB), University Medical Center Göttingen, Göttingen 37077, Germany
| | - Ute M Moll
- Institute of Molecular Oncology, Göttingen Center for Molecular Biosciences (GZMB), University Medical Center Göttingen, Göttingen 37077, Germany.,Department of Pathology, School of Medicine, Stony Brook University, Stony Brook, NY 11794, USA
| | - Matthias Dobbelstein
- Institute of Molecular Oncology, Göttingen Center for Molecular Biosciences (GZMB), University Medical Center Göttingen, Göttingen 37077, Germany
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18
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Castellini L, Moon EJ, Razorenova OV, Krieg AJ, von Eyben R, Giaccia AJ. KDM4B/JMJD2B is a p53 target gene that modulates the amplitude of p53 response after DNA damage. Nucleic Acids Res 2017; 45:3674-3692. [PMID: 28073943 PMCID: PMC5397198 DOI: 10.1093/nar/gkw1281] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 12/12/2016] [Indexed: 12/14/2022] Open
Abstract
The p53 tumor suppressor protein plays a critical role in orchestrating the genomic response to various stress signals by acting as a master transcriptional regulator. Differential gene activity is controlled by transcription factors but also dependent on the underlying chromatin structure, especially on covalent histone modifications. After screening different histone lysine methyltransferases and demethylases, we identified JMJD2B/KDM4B as a p53-inducible gene in response to DNA damage. p53 directly regulates JMJD2B gene expression by binding to a canonical p53-consensus motif in the JMJD2B promoter. JMJD2B induction attenuates the transcription of key p53 transcriptional targets including p21, PIG3 and PUMA, and this modulation is dependent on the catalytic capacity of JMJD2B. Conversely, JMJD2B silencing led to an enhancement of the DNA-damage driven induction of p21 and PIG3. These findings indicate that JMJD2B acts in an auto-regulatory loop by which p53, through JMJD2B activation, is able to influence its own transcriptional program. Functionally, exogenous expression of JMJD2B enhanced subcutaneous tumor growth of colon cancer cells in a p53-dependent manner, and genetic inhibition of JMJD2B impaired tumor growth in vivo. These studies provide new insights into the regulatory effect exerted by JMJD2B on tumor growth through the modulation of p53 target genes.
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Affiliation(s)
- Laura Castellini
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Eui Jung Moon
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Olga V Razorenova
- Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, CA 92697, USA
| | - Adam J Krieg
- Department of Obstetrics and Gynecology, Oregon Health and Sciences University, Portland, OR 97239, USA
| | - Rie von Eyben
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Amato J Giaccia
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA
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19
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Lu W, Katzenellenbogen BS. Estrogen Receptor-β Modulation of the ERα-p53 Loop Regulating Gene Expression, Proliferation, and Apoptosis in Breast Cancer. Discov Oncol 2017; 8:230-242. [PMID: 28577282 DOI: 10.1007/s12672-017-0298-1] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 05/19/2017] [Indexed: 02/06/2023] Open
Abstract
Estrogen receptor α (ERα) is a crucial transcriptional regulator in breast cancer, but estrogens mediate their effects through two estrogen receptors, ERα and ERβ, subtypes that have contrasting regulatory actions on gene expression and the survival and growth of breast cancer cells. Here, we examine the impact of ERβ on the ERα-p53 loop in breast cancer. We found that ERβ attenuates ERα-induced cell proliferation, increases apoptosis, and reverses transcriptional activation and repression by ERα. Further, ERβ physically interacts with p53, reduces ERα-p53 binding, and antagonizes ERα-p53-mediated transcriptional regulation. ERα directs SUV39H1/H2 and histone H3 lys9 trimethylation (H3K9me3) heterochromatin assembly at estrogen-repressed genes to silence p53-activated transcription. The copresence of ERβ in ERα-positive cells abrogates the H3K9me3 repressive heterochromatin conformation by downregulating SUV39H1 and SUV39H2, thereby releasing the ERα-induced transcriptional block. Furthermore, the presence of ERβ stimulates accumulation of histone H3 lys4 trimethylation (H3K4me3) and RNA polymerase II (RNA Pol II) on ERα-repressed genes, inducing H3K4me3-associated epigenetic activation of the transcription of these repressed genes that can promote p53-based tumor suppression. ERβ also reduced corepressor N-CoR and SMRT recruitment by ERα that could attenuate the crosstalk between ERα and p53. Overall, our data reveal a novel mechanism for ERβ's anti-proliferative and pro-apoptotic effects in breast cancer cells involving p53 and epigenetic changes in histone methylation that underlie gene regulation of these cellular activities.
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Affiliation(s)
- Wenwen Lu
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, 524 Burrill Hall, 407 South Goodwin Avenue, Urbana, IL, 61801-3704, USA
| | - Benita S Katzenellenbogen
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, 524 Burrill Hall, 407 South Goodwin Avenue, Urbana, IL, 61801-3704, USA.
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20
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Mutant p53 perturbs DNA replication checkpoint control through TopBP1 and Treslin. Proc Natl Acad Sci U S A 2017; 114:E3766-E3775. [PMID: 28439015 DOI: 10.1073/pnas.1619832114] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Accumulating evidence supports the gain-of-function of mutant forms of p53 (mutp53s). However, whether mutp53 directly perturbs the DNA replication checkpoint remains unclear. Previously, we have demonstrated that TopBP1 forms a complex with mutp53s and mediates their gain-of-function through NF-Y and p63/p73. Akt phosphorylates TopBP1 and induces its oligomerization, which inhibits its ATR-activating function. Here we show that various contact and conformational mutp53s bypass Akt to induce TopBP1 oligomerization and attenuate ATR checkpoint response during replication stress. The effect on ATR response caused by mutp53 can be exploited in a synthetic lethality strategy, as depletion of another ATR activator, DNA2, in mutp53-R273H-expressing cancer cells renders cells hypersensitive to cisplatin. Expression of mutp53-R273H also makes cancer cells more sensitive to DNA2 depletion or DNA2 inhibitors. In addition to ATR-activating function during replication stress, TopBP1 interacts with Treslin in a Cdk-dependent manner to initiate DNA replication during normal growth. We find that mutp53 also interferes with TopBP1 replication function. Several contact, but not conformational, mutp53s enhance the interaction between TopBP1 and Treslin and promote DNA replication despite the presence of a Cdk2 inhibitor. Together, these data uncover two distinct mechanisms by which mutp53 enhances DNA replication: (i) Both contact and conformational mutp53s can bind TopBP1 and attenuate the checkpoint response to replication stress, and (ii) during normal growth, contact (but not conformational) mutp53s can override the Cdk2 requirement to promote replication by facilitating the TopBP1/Treslin interaction.
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21
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Chen TT, Wu SM, Ho SC, Chuang HC, Liu CY, Chan YF, Kuo LW, Feng PH, Liu WT, Chen KY, Hsiao TC, Juang JN, Lee KY. SUV39H1 Reduction Is Implicated in Abnormal Inflammation in COPD. Sci Rep 2017; 7:46667. [PMID: 28425504 PMCID: PMC5397975 DOI: 10.1038/srep46667] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 03/22/2017] [Indexed: 12/23/2022] Open
Abstract
Chronic obstructive pulmonary disease(COPD) is characterized by enhanced chronic inflammation in the airways, lung parenchyma, and circulation. We investigated whether SUV39H1, a histone methyltransferase, is causatively implicated in the abnormal inflammation observed in COPD. The SUV39H1 and H3K9me3 levels were reduced in peripheral blood mononuclear cells(PBMCs), primary human small airway epithelial cells(HSAEpCs) and lung tissues from COPD patients, which were correlated with poor lung function and the serum IL-8 and IL-6 levels. A specific SUV39H1 inhibitor, chaetocin, induced a distinct COPD panel of inflammatory cytokines in normal PBMCs. Mechanistically, chaetocin reduced the SUV39H1 and H3K9me3 levels in the native IL-8 promoter in normal HSAEpCs, which mimicked unstimulated COPD HSAEpCs and led to decreased HP-1α levels and increased RNA polymerase II levels. SUV39H1 knockdown reproduced the pattern of COPD inflammation, whereas SUV39H1 overexpression in COPD HSAEpCs rescued the H3K9me3 levels and suppressed inflammation. In COPD mice, chaetocin further repressed the SUV39H1/H3K9me3 levels and enhanced inflammation. SUV39H1 epigenetically controls a distinct panel of pro-inflammatory cytokines. Its reduction in COPD leads to a loss of the repressive chromatin mark H3K9me3 and confers an abnormal inflammatory response to stimulators. SUV39H1 and its regulatory pathways are potential therapeutic targets for COPD.
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Affiliation(s)
- Tzu-Tao Chen
- Division of Pulmonary Medicine, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan.,Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Sheng-Ming Wu
- Division of Pulmonary Medicine, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan
| | - Shu-Chuan Ho
- Division of Pulmonary Medicine, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan.,School of Respiratory Therapy, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Hsiao-Chi Chuang
- Division of Pulmonary Medicine, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan.,School of Respiratory Therapy, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Division of Pulmonary Medicine, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Chien-Ying Liu
- Division of Pulmonary Oncology and Interventional Bronchoscopy, Department of Thoracic Medicine, Linkou Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan
| | - Yao-Fei Chan
- Division of Pulmonary Medicine, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan
| | - Lu-Wei Kuo
- Division of Pulmonary Medicine, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan
| | - Po-Hao Feng
- Division of Pulmonary Medicine, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan.,Division of Pulmonary Medicine, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Wen-Te Liu
- Division of Pulmonary Medicine, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan.,School of Respiratory Therapy, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Division of Pulmonary Medicine, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Department of Engineering Science, National Cheng Kung University, Tainan, Taiwan
| | - Kuan-Yuan Chen
- Division of Pulmonary Medicine, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan.,Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Ta-Chih Hsiao
- Graduate Institute of Environmental Engineering, National Central University, Taoyuan, Taiwan
| | - Jer-Nan Juang
- Department of Engineering Science, National Cheng Kung University, Tainan, Taiwan
| | - Kang-Yun Lee
- Division of Pulmonary Medicine, Department of Internal Medicine, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan.,Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Division of Pulmonary Medicine, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
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22
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USP7 Enforces Heterochromatinization of p53 Target Promoters by Protecting SUV39H1 from MDM2-Mediated Degradation. Cell Rep 2016; 14:2528-37. [PMID: 26971997 DOI: 10.1016/j.celrep.2016.02.049] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 12/24/2015] [Accepted: 02/07/2016] [Indexed: 12/27/2022] Open
Abstract
The H3K9me3 repressive histone conformation of p53 target promoters is abrogated in response to p53 activation by MDM2-mediated SUV39H1 degradation. Here, we present evidence that the USP7 deubiquitinase protects SUV39H1 from MDM2-mediated ubiquitination in the absence of p53 stimulus. USP7 occupies p53 target promoters in unstressed conditions, a process that is abrogated with p53 activation associated with loss of the H3K9me3 mark on these same promoters. Mechanistically, USP7 forms a trimeric complex with MDM2 and SUV39H1, independent of DNA, and modulates MDM2-dependent SUV39H1 ubiquitination. Furthermore, we show that this protective function of USP7 on SUV39H1 is independent of p53. Finally, USP7 blocking cooperates with p53 in inducing apoptosis by enhancing p53 promoter occupancy and dependent transactivation of target genes. These results uncover a layer of the p53 transcriptional program mediated by USP7, which restrains relaxation of local chromatin conformation at p53 target promoters.
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Olcina MM, Leszczynska KB, Senra JM, Isa NF, Harada H, Hammond EM. H3K9me3 facilitates hypoxia-induced p53-dependent apoptosis through repression of APAK. Oncogene 2016; 35:793-9. [PMID: 25961932 PMCID: PMC4753255 DOI: 10.1038/onc.2015.134] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 01/22/2015] [Accepted: 03/10/2015] [Indexed: 12/24/2022]
Abstract
Regions of hypoxia occur in most solid tumors, and they are associated with a poor prognostic outcome. Despite the absence of detectable DNA damage, severe hypoxia (<0.1% O2) induces a DNA damage response, including the activation of p53 and subsequent induction of p53-dependent apoptosis. Factors affecting hypoxia-induced p53-dependent apoptosis are unclear. Here we asked whether H3K9me3, through mediating gene repression, could regulate hypoxia-induced p53-dependent apoptosis. Under hypoxic conditions, increases in H3K9me3 occur in an oxygen-dependent but HIF-1-independent manner. We demonstrate that under hypoxic conditions, which induce p53 activity, the negative regulator of p53, APAK, is repressed by increases in H3K9me3 along the APAK loci. APAK repression in hypoxia is mediated by the methyltransferase SETDB1 but not Suv39h1 or G9a. Interestingly, increasing hypoxia-induced H3K9me3 through pharmacological inhibition of JMJD2 family members leads to an increase in apoptosis and decreased clonogenic survival and again correlates with APAK expression. The relevance of understanding the mechanisms of APAK expression regulation to human disease was suggested by analysis of patients with colorectal cancer, which demonstrates that high APAK expression correlates with poor prognosis. Together, these data demonstrate the functional importance of H3K9me3 in hypoxia, and they provide a novel mechanistic link between H3K9me3, p53 and apoptosis in physiologically relevant conditions of hypoxia.
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Affiliation(s)
- M M Olcina
- Department of Oncology, CR-UK & MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, UK
| | - K B Leszczynska
- Department of Oncology, CR-UK & MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, UK
| | - J M Senra
- Department of Oncology, CR-UK & MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, UK
| | - N F Isa
- Department of Oncology, CR-UK & MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, UK
| | - H Harada
- Department of Radiation Oncology and Image-Applied Therapy, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - E M Hammond
- Department of Oncology, CR-UK & MRC Oxford Institute for Radiation Oncology, University of Oxford, Oxford, UK
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Park SY, Park JW, Chun YS. Jumonji histone demethylases as emerging therapeutic targets. Pharmacol Res 2016; 105:146-51. [PMID: 26816087 DOI: 10.1016/j.phrs.2016.01.026] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 01/21/2016] [Indexed: 11/28/2022]
Abstract
The methylation status of lysine residues in histones determines the transcription of surrounding genes by modulating the chromatin architecture. Jumonji domain-containing histone-lysine demethylases (Jmj-KDMs) remove the methyl moiety from lysine residues in histones by utilizing Fe(2+) and α-ketoglutarate. Since genetic alterations in Jmj-KDMs occur in various human cancers, the roles of Jmj-KDMs in cancer development and progression have been investigated, but still controversial. The KDM7 subfamily, which belongs to the Jmj-KDM family, is an emerging class of transcriptional coactivators because its members erase the repressive marks H3K9me2/1, H3K27me2/1, and H4K20 me1. Recently, KDM7C (alternatively named PHF2) was discovered as a new KDM7 member and identified to play a tumor-suppressive role through the reinforcement of p53-driven growth arrest and apoptosis. In this article, we generally reviewed the roles of Jmj-KDMs in human cancers and more discussed the molecular functions and the clinical significances of KDM7C.
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Affiliation(s)
- Sung Yeon Park
- Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea
| | - Jong-Wan Park
- Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea; Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea
| | - Yang-Sook Chun
- Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea; Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea; Department of Physiology, Seoul National University College of Medicine, Seoul 110-799, Republic of Korea.
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25
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Abstract
The predominant function of the tumor suppressor p53 is transcriptional regulation. It is generally accepted that p53-dependent transcriptional activation occurs by binding to a specific recognition site in promoters of target genes. Additionally, several models for p53-dependent transcriptional repression have been postulated. Here, we evaluate these models based on a computational meta-analysis of genome-wide data. Surprisingly, several major models of p53-dependent gene regulation are implausible. Meta-analysis of large-scale data is unable to confirm reports on directly repressed p53 target genes and falsifies models of direct repression. This notion is supported by experimental re-analysis of representative genes reported as directly repressed by p53. Therefore, p53 is not a direct repressor of transcription, but solely activates its target genes. Moreover, models based on interference of p53 with activating transcription factors as well as models based on the function of ncRNAs are also not supported by the meta-analysis. As an alternative to models of direct repression, the meta-analysis leads to the conclusion that p53 represses transcription indirectly by activation of the p53-p21-DREAM/RB pathway.
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Key Words
- CDE, cell cycle-dependent element
- CDKN1A
- CHR, cell cycle genes homology region
- ChIP, chromatin immunoprecipitation
- DREAM complex
- DREAM, DP, RB-like, E2F4, and MuvB complex
- E2F/RB complex
- HPV, human papilloma virus
- NF-Y, Nuclear factor Y
- cdk, cyclin-dependent kinase
- genome-wide meta-analysis
- p53
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Affiliation(s)
- Martin Fischer
- a Molecular Oncology; Medical School ; University of Leipzig ; Leipzig , Germany
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26
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Puzio-Kuter AM, Laddha SV, Castillo-Martin M, Sun Y, Cordon-Cardo C, Chan CS, Levine AJ. Involvement of tumor suppressors PTEN and p53 in the formation of multiple subtypes of liposarcoma. Cell Death Differ 2015; 22:1785-91. [PMID: 25822339 PMCID: PMC4648325 DOI: 10.1038/cdd.2015.27] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 01/21/2015] [Accepted: 02/12/2015] [Indexed: 12/26/2022] Open
Abstract
Liposarcoma (LPS) is a type of soft tissue sarcoma that mostly occurs in adults, and in humans is characterized by amplifications of MDM2 and CDK4. The molecular pathogenesis of this malignancy is still poorly understood and, therefore, we developed a mouse model with conditional inactivation of PTEN and p53 to investigate these pathways in the progression of the disease. We show that deletion of these two tumor suppressors cooperate in the formation of multiple subtypes of LPS (from well-differentiated LPS to pleomorphic LPS). In addition, progression of the tumors is further characterized by the expression of D cyclins and CDK4/6, which allow for continued cell division. Microarray analysis also revealed novel genes that are differentially expressed between different subtypes of LPS, which could aid in understanding the disease and to unravel potential new therapeutic targets.
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Affiliation(s)
- A M Puzio-Kuter
- Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey, USA
| | - S V Laddha
- Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey, USA
| | - M Castillo-Martin
- Icahn School of Medicine at Mount Sinai, Mount Sinai School of Medicine, New York, USA
| | - Y Sun
- Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey, USA
| | - C Cordon-Cardo
- Icahn School of Medicine at Mount Sinai, Mount Sinai School of Medicine, New York, USA
| | - C S Chan
- Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey, USA.,Department of Medicine, Rutgers Robert Wood Johnson Medical School, New Jersey, USA
| | - A J Levine
- Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey, USA.,Institute for Advanced Study, Princeton, New Jersey, USA
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27
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No JG, Choi MK, Kwon DJ, Yoo JG, Yang BC, Park JK, Kim DH. Cell-free extract from porcine induced pluripotent stem cells can affect porcine somatic cell nuclear reprogramming. J Reprod Dev 2015; 61:90-8. [PMID: 25736622 PMCID: PMC4410095 DOI: 10.1262/jrd.2014-078] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Pretreatment of somatic cells with undifferentiated cell extracts, such as embryonic stem cells and mammalian oocytes, is an attractive alternative method for reprogramming control. The properties of induced pluripotent stem cells (iPSCs) are similar to those of embryonic stem cells; however, no studies have reported somatic cell nuclear reprogramming using iPSC extracts. Therefore, this study aimed to evaluate the effects of porcine iPSC extracts treatment on porcine ear fibroblasts and early development of porcine cloned embryos produced from porcine ear skin fibroblasts pretreated with the porcine iPSC extracts. The Chariot(TM) reagent system was used to deliver the iPSC extracts into cultured porcine ear skin fibroblasts. The iPSC extracts-treated cells (iPSC-treated cells) were cultured for 3 days and used for analyzing histone modification and somatic cell nuclear transfer. Compared to the results for nontreated cells, the trimethylation status of histone H3 lysine residue 9 (H3K9) in the iPSC-treated cells significantly decreased. The expression of Jmjd2b, the H3K9 trimethylation-specific demethylase gene, significantly increased in the iPSC-treated cells; conversely, the expression of the proapoptotic genes, Bax and p53, significantly decreased. When the iPSC-treated cells were transferred into enucleated porcine oocytes, no differences were observed in blastocyst development and total cell number in blastocysts compared with the results for control cells. However, H3K9 trimethylation of pronuclear-stage-cloned embryos significantly decreased in the iPSC-treated cells. Additionally, Bax and p53 gene expression in the blastocysts was significantly lower in iPSC-treated cells than in control cells. To our knowledge, this study is the first to show that an extracts of porcine iPSCs can affect histone modification and gene expression in porcine ear skin fibroblasts and cloned embryos.
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Affiliation(s)
- Jin-Gu No
- Animal Biotechnology Division; Department of Biological Science, Sungkyunkwan University, Suwon 440-746, Republic of Korea
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28
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Öst A, Pospisilik JA. Epigenetic modulation of metabolic decisions. Curr Opin Cell Biol 2015; 33:88-94. [PMID: 25588618 DOI: 10.1016/j.ceb.2014.12.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 12/17/2014] [Accepted: 12/18/2014] [Indexed: 12/17/2022]
Abstract
In the recent years there has been a tremendous increase in our understanding of chromatin, transcription and the importance of metabolites in their regulation. This review highlights what is currently sparse information that suggest existence of a refined system integrating metabolic and chromatin control. We indicate possible regulatory modes, such as feed forward amplification, that may help effect and stabilize long-lasting phenotypic decisions within and even across generations using adipogenesis as the primary context.
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Affiliation(s)
- Anita Öst
- Department of Clinical and Experimental Medicine, Linkoping University, 58183 Linkoping, Sweden
| | - John Andrew Pospisilik
- Max Planck Institute of Immunobiology and Epigenetics, Stuebeweg 51, 79108 Freiburg, Germany.
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29
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Sidler C, Li D, Wang B, Kovalchuk I, Kovalchuk O. SUV39H1 downregulation induces deheterochromatinization of satellite regions and senescence after exposure to ionizing radiation. Front Genet 2014; 5:411. [PMID: 25484892 PMCID: PMC4240170 DOI: 10.3389/fgene.2014.00411] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Accepted: 11/05/2014] [Indexed: 12/22/2022] Open
Abstract
While the majority of cancer patients are exposed to ionizing radiation during diagnostic and therapeutic procedures, age-dependent differences in radiation sensitivity are not yet well understood. Radiation sensitivity is characterized by the appearance of side effects to radiation therapy, such as secondary malignancies, developmental deficits, and compromised immune function. However, the knowledge of the molecular mechanisms that trigger these side effects is incomplete. Here we used an in vitro system and showed that low-senescent normal human diploid fibroblasts (WI-38) senesce in response to 5 Gy IR, while highly senescent cultures do not show changes in cell cycle regulation and only a slight increase in the percentage of senescent cells. Our study shows that this is associated with changes in the expression of genes responsible for cell cycle progression, apoptosis, DNA repair, and aging, as well as transcriptional and epigenetic regulators. Furthermore, we propose a role of the downregulation of SUV39H1 expression, a histone methyltransferase that specifically trimethylates H3K9, and the corresponding reduction in H3K9me3 levels in the establishment of IR-induced senescence.
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Affiliation(s)
- Corinne Sidler
- Department of Biological Sciences, University of Lethbridge Lethbridge, AB, Canada
| | - Dongping Li
- Department of Biological Sciences, University of Lethbridge Lethbridge, AB, Canada
| | - Bo Wang
- Department of Biological Sciences, University of Lethbridge Lethbridge, AB, Canada
| | - Igor Kovalchuk
- Department of Biological Sciences, University of Lethbridge Lethbridge, AB, Canada
| | - Olga Kovalchuk
- Department of Biological Sciences, University of Lethbridge Lethbridge, AB, Canada
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30
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Sammons MA, Zhu J, Drake AM, Berger SL. TP53 engagement with the genome occurs in distinct local chromatin environments via pioneer factor activity. Genome Res 2014; 25:179-88. [PMID: 25391375 PMCID: PMC4315292 DOI: 10.1101/gr.181883.114] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Despite overwhelming evidence that transcriptional activation by TP53 is critical for its tumor suppressive activity, the mechanisms by which TP53 engages the genome in the context of chromatin to activate transcription are not well understood. Using a compendium of novel and existing genome-wide data sets, we examined the relationship between TP53 binding and the dynamics of the local chromatin environment. Our analysis revealed three distinct categories of TP53 binding events that differ based on the dynamics of the local chromatin environment. The first class of TP53 binding events occurs near transcriptional start sites (TSS) and is defined by previously characterized promoter-associated chromatin modifications. The second class comprises a large cohort of preestablished, promoter-distal enhancer elements that demonstrates dynamic histone acetylation and transcription upon TP53 binding. The third class of TP53 binding sites is devoid of classic chromatin modifications and, remarkably, fall within regions of inaccessible chromatin, suggesting that TP53 has intrinsic pioneer factor activity and binds within structurally inaccessible regions of chromatin. Intriguingly, these inaccessible TP53 binding sites feature several enhancer-like properties in cell types within the epithelial lineage, indicating that TP53 binding events include a group of “proto-enhancers” that become active enhancers given the appropriate cellular context. These data indicate that TP53, along with TP63, may act as pioneer factors to specify epithelial enhancers. Further, these findings suggest that rather than following a global cell-type invariant stress response program, TP53 may tune its response based on the lineage-specific epigenomic landscape.
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Affiliation(s)
- Morgan A Sammons
- Departments of Cell and Developmental Biology, Genetics, and Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA; Penn Epigenetics Program, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Jiajun Zhu
- Departments of Cell and Developmental Biology, Genetics, and Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA; Penn Epigenetics Program, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Adam M Drake
- Departments of Cell and Developmental Biology, Genetics, and Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA; Penn Epigenetics Program, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Shelley L Berger
- Departments of Cell and Developmental Biology, Genetics, and Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA; Penn Epigenetics Program, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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31
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Abstract
Post-translational modifications provide a fine-tuned control of protein function(s) in the cell. The well-known tumour suppressor p53 is subject to many post-translational modifications, which alter its activity, localization and stability, thus ultimately modulating its response to various forms of genotoxic stress. In this review, we focus on the role of recently discovered lysine-specific modifications of p53, methylation and acetylation in particular, and their effects on p53 activity in damaged cells. We also discuss a possibility of mutual influence of covalent modifications in the p53 and histone proteins located in the vicinity of p53 binding sites in chromatin and propose important ramifications stemming from this hypothesis.
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32
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Lee KH, Park JW, Sung HS, Choi YJ, Kim WH, Lee HS, Chung HJ, Shin HW, Cho CH, Kim TY, Li SH, Youn HD, Kim SJ, Chun YS. PHF2 histone demethylase acts as a tumor suppressor in association with p53 in cancer. Oncogene 2014; 34:2897-909. [PMID: 25043306 DOI: 10.1038/onc.2014.219] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 05/05/2014] [Accepted: 06/15/2014] [Indexed: 12/14/2022]
Abstract
Plant homeodomain finger 2 (PHF2) has a role in epigenetic regulation of gene expression by demethylating H3K9-Me2. Several genome-wide studies have demonstrated that the chromosomal region including the PHF2 gene is often deleted in some cancers including colorectal cancer, and this finding encouraged us to investigate the tumor suppressive role of PHF2. As p53 is a critical tumor suppressor in colon cancer, we tested the possibility that PHF2 is an epigenetic regulator of p53. PHF2 was associated with p53, and thereby, promoted p53-driven gene expression in cancer cells under genotoxic stress. PHF2 converted the chromatin that is favorable for transcription by demethylating the repressive H3K9-Me2 mark. In an HCT116 xenograft model, PHF2 was found to be required for the anticancer effects of oxaliplatin and doxorubicin. In PHF2-deficient xenografts, p53 expression was profoundly induced by both drugs, but its downstream product p21 was not, suggesting that p53 cannot be activated in the absence of PHF2. To find clinical evidence about the role of PHF2, we analyzed the expressions of PHF2, p53 and p21 in human colon cancer tissues and adjacent normal tissues from patients. PHF2 was downregulated in cancer tissues and PHF2 correlated with p21 in cancers expressing functional p53. Colon and stomach cancer tissue arrays showed a positive correlation between PHF2 and p21 expressions. Informatics analyses using the Oncomine database also supported our notion that PHF2 is downregulated in colon and stomach cancers. On the basis of these findings, we propose that PHF2 acts as a tumor suppressor in association with p53 in cancer development and ensures p53-mediated cell death in response to chemotherapy.
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Affiliation(s)
- K-H Lee
- Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - J-W Park
- 1] Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul, Republic of Korea [2] Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - H-S Sung
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Y-J Choi
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - W H Kim
- Department of Pathology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - H S Lee
- Department of Pathology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - H-J Chung
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - H-W Shin
- Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - C-H Cho
- 1] Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul, Republic of Korea [2] Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - T-Y Kim
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - S-H Li
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - H-D Youn
- 1] Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul, Republic of Korea [2] Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - S J Kim
- 1] Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul, Republic of Korea [2] Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea [3] Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Y-S Chun
- 1] Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul, Republic of Korea [2] Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea [3] Department of Physiology, Seoul National University College of Medicine, Seoul, Republic of Korea
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Ash2L enables P53-dependent apoptosis by favoring stable transcription pre-initiation complex formation on its pro-apoptotic target promoters. Oncogene 2014; 34:2461-70. [PMID: 25023704 PMCID: PMC4295002 DOI: 10.1038/onc.2014.198] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Revised: 05/07/2014] [Accepted: 05/21/2014] [Indexed: 01/20/2023]
Abstract
Chromatin conformation plays a major role in all cellular decisions. We showed previously that P53 pro-apoptotic target promoters are enriched with H3K9me3 mark and induction of P53 abrogates this repressive chromatin conformation by down-regulating SUV39H1, the writer of this mark present on these promoters. In the present study, we demonstrate that in response to P53 stabilization, its pro-apoptotic target promoters become enriched with the H3K4me3 epigenetic mark as well as its readers, Wdr5, RbBP5 and Ash2L, which were not observed in response to SUV39H1 down-regulation alone. Overexpression of Ash2L enhanced P53–dependent apoptosis in response to chemotherapy, associated with increased P53 pro–apoptotic gene promoter occupancy and target gene expression. In contrast, pre–silencing of Ash2L abrogated P53's ability to induce the expression of these transcriptional targets, without affecting P53 or RNAP II recruitment. However, Ash2L pre–silencing, under the same conditions, resulted in reduced RNAP II ser5–CTD phosphorylation on these same pro-apoptotic target promoters, which correlated with reduced promoter occupancy of TFIIB as well as TFIIF (RAP74). Based on these findings, we propose that Ash2L acts in concert with P53 promoter occupancy to activate RNAP II by aiding formation of a stable transcription pre–initiation complex required for its activation.
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34
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Noh HJ, Kim KA, Kim KC. p53 down-regulates SETDB1 gene expression during paclitaxel induced-cell death. Biochem Biophys Res Commun 2014; 446:43-8. [PMID: 24565839 DOI: 10.1016/j.bbrc.2014.02.053] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2014] [Accepted: 02/11/2014] [Indexed: 10/25/2022]
Abstract
Paclitaxel (PTX) is a chemotherapeutic drug which induces tubulin stability and regulates expression of death related genes in human cancer cells. Its anticancer mechanism is well known, however its effects on chromatin remodeling factors are poorly understood. In this study, we examine if PTX affects expression of SETDB1 HMTase during cell death. PTX induces cell death via G2/M arrest in human lung cancer cells. PTX treatment induces the p53 protein, but down-regulates expression of SETDB1 at the transcriptional level as well as the protein level. SETDB1 promoter activity is increased to approximately 30-fold in normal condition, but the activity is significantly inhibited in the PTX treated group. In addition, p53 transfection inhibits SETDB1 promoter activity. The p53 protein directly binds to proximal region of the SETDB1 promoter, and H3K9me3 occupancy in this region also increased in the presence of p53. Immunoprecipitation experiment showed interaction of p53 and SUV39H1, suggesting that association of p53 and SUV39H1 is responsible for increased H3K9me3 occupancy and transcription repression of SETDB1. This result demonstrates that PTX down-regulates SETDB1 gene expression in a p53 dependent manner, and p53 might participate in heterochromatic repression on the promoter regions of SETDB1.
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Affiliation(s)
- Hee-Jung Noh
- Medical & Bio-Material Research Center, Department of Biological Sciences, College of Natural Sciences, Kangwon National University, Chuncheon 200-701, Republic of Korea
| | - Kyeong-Ah Kim
- Medical & Bio-Material Research Center, Department of Biological Sciences, College of Natural Sciences, Kangwon National University, Chuncheon 200-701, Republic of Korea
| | - Keun-Cheol Kim
- Medical & Bio-Material Research Center, Department of Biological Sciences, College of Natural Sciences, Kangwon National University, Chuncheon 200-701, Republic of Korea.
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35
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Cho Y, Kim KH, Cho YS, Xu W, Wang X, Kwon HJ. A histone demethylase inhibitor, methylstat, inhibits angiogenesis in vitro and in vivo. RSC Adv 2014. [DOI: 10.1039/c4ra07154a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Histone methylation has been highlighted in the regulation of gene expression. Methylstat, a Jumonji C domain containing histone demethylase inhibitor, inhibitedin vitroandin vivoangiogenesis at nontoxic dose. Collectively, methylstat could be a promising chemical probe for addressing its role in angiogenesis
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Affiliation(s)
- Yumi Cho
- Chemical Genomics National Research Laboratory
- Department of Biotechnology
- Translational Research Center for Protein Function Control
- College of Life Science & Biotechnology
- Yonsei University
| | - Ki Hyun Kim
- Chemical Genomics National Research Laboratory
- Department of Biotechnology
- Translational Research Center for Protein Function Control
- College of Life Science & Biotechnology
- Yonsei University
| | - Yoon Sun Cho
- Chemical Genomics National Research Laboratory
- Department of Biotechnology
- Translational Research Center for Protein Function Control
- College of Life Science & Biotechnology
- Yonsei University
| | - Wenqing Xu
- Department of Chemistry and Biochemistry
- University of Colorado
- Boulder, USA
| | - Xiang Wang
- Department of Chemistry and Biochemistry
- University of Colorado
- Boulder, USA
| | - Ho Jeong Kwon
- Chemical Genomics National Research Laboratory
- Department of Biotechnology
- Translational Research Center for Protein Function Control
- College of Life Science & Biotechnology
- Yonsei University
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Olcina MM, Foskolou IP, Anbalagan S, Senra JM, Pires IM, Jiang Y, Ryan AJ, Hammond EM. Replication stress and chromatin context link ATM activation to a role in DNA replication. Mol Cell 2013; 52:758-66. [PMID: 24268576 PMCID: PMC3898930 DOI: 10.1016/j.molcel.2013.10.019] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 08/28/2013] [Accepted: 10/07/2013] [Indexed: 01/08/2023]
Abstract
ATM-mediated signaling in response to DNA damage is a barrier to tumorigenesis. Here we asked whether replication stress could also contribute to ATM signaling. We demonstrate that, in the absence of DNA damage, ATM responds to replication stress in a hypoxia-induced heterochromatin-like context. In certain hypoxic conditions, replication stress occurs in the absence of detectable DNA damage. Hypoxia also induces H3K9me3, a histone modification associated with gene repression and heterochromatin. Hypoxia-induced replication stress together with increased H3K9me3 leads to ATM activation. Importantly, ATM prevents the accumulation of DNA damage in hypoxia. Most significantly, we describe a stress-specific role for ATM in maintaining DNA replication rates in a background of increased H3K9me3. Furthermore, the ATM-mediated response to oncogene-induced replication stress is enhanced in hypoxic conditions. Together, these data indicate that hypoxia plays a critical role in the activation of the DNA damage response, therefore contributing to this barrier to tumorigenesis.
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Affiliation(s)
- Monica M Olcina
- The Gray Institute for Radiation Oncology and Biology, Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK
| | - Iosifina P Foskolou
- The Gray Institute for Radiation Oncology and Biology, Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK
| | - Selvakumar Anbalagan
- The Gray Institute for Radiation Oncology and Biology, Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK
| | - Joana M Senra
- The Gray Institute for Radiation Oncology and Biology, Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK
| | - Isabel M Pires
- The Gray Institute for Radiation Oncology and Biology, Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK
| | - Yanyan Jiang
- The Gray Institute for Radiation Oncology and Biology, Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK
| | - Anderson J Ryan
- The Gray Institute for Radiation Oncology and Biology, Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK
| | - Ester M Hammond
- The Gray Institute for Radiation Oncology and Biology, Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK.
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Chromatin modifications sequentially enhance ErbB2 expression in ErbB2-positive breast cancers. Cell Rep 2013; 5:302-13. [PMID: 24120871 DOI: 10.1016/j.celrep.2013.09.009] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 08/04/2013] [Accepted: 09/06/2013] [Indexed: 01/03/2023] Open
Abstract
ErbB2 gene amplification occurs in 20%-25% of breast cancers, and its therapeutic targeting has markedly improved survival of patients with breast cancer in the adjuvant setting. However, resistance to these therapies can develop. Because epigenetic mechanisms can importantly influence oncogene expression and be druggable as well, we investigated histone modifications that influence ErbB2 overexpression, independent of gene amplification. We demonstrate here that ErbB2-overexpressing breast carcinomas acquire the H3K4me3 mark on the erbB2 promoter and that receptor-amplified tumors further acquire the H3K9ac mark, which is dependent on H3K4me3 mark acquisition. Targeting WD repeat domain 5 (Wdr5), which is absolutely required for H3K4me3 enrichment, decreased ErbB2 overexpression, associated with a decrease in the H3K4me3 mark on the erbB2 promoter. Of note, Wdr5 silencing cooperated with trastuzumab or chemotherapy in specifically inhibiting the growth of ErbB2-positive breast tumor cells. Thus, our studies illuminate epigenetic steps in the selection for ErbB2 activation.
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p53-dependent gene repression through p21 is mediated by recruitment of E2F4 repression complexes. Oncogene 2013; 33:3959-69. [PMID: 24096481 PMCID: PMC4067464 DOI: 10.1038/onc.2013.378] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 07/03/2013] [Accepted: 07/12/2013] [Indexed: 02/06/2023]
Abstract
The p53 tumor suppressor protein is a major sensor of cellular stresses, and upon stabilization, activates or represses many genes that control cell fate decisions. While the mechanism of p53-mediated transactivation is well established, several mechanisms have been proposed for p53-mediated repression. Here, we demonstrate that the cyclin-dependent kinase inhibitor p21 is both necessary and sufficient for the downregulation of known p53-repression targets, including survivin, CDC25C, and CDC25B in response to p53 induction. These same targets are similarly repressed in response to p16 overexpression, implicating the involvement of the shared downstream retinoblastoma (RB)-E2F pathway. We further show that in response to either p53 or p21 induction, E2F4 complexes are specifically recruited onto the promoters of these p53-repression targets. Moreover, abrogation of E2F4 recruitment via the inactivation of RB pocket proteins, but not by RB loss of function alone, prevents the repression of these genes. Finally, our results indicate that E2F4 promoter occupancy is globally associated with p53-repression targets, but not with p53 activation targets, implicating E2F4 complexes as effectors of p21-dependent p53-mediated repression.
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Keller C, Guttridge DC. Mechanisms of impaired differentiation in rhabdomyosarcoma. FEBS J 2013; 280:4323-34. [PMID: 23822136 DOI: 10.1111/febs.12421] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 06/17/2013] [Accepted: 07/01/2013] [Indexed: 12/22/2022]
Abstract
Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma of childhood, with presumed skeletal muscle origins, because of its myogenic phenotype. RMS is composed of two main subtypes, embryonal RMS (eRMS) and alveolar RMS (aRMS). Whereas eRMS histologically resembles embryonic skeletal muscle, the aRMS subtype is more aggressive and has a poorer prognosis. In addition, whereas the genetic profile of eRMS is not well established, aRMS is commonly associated with distinct chromosome translocations that fuse domains of the transcription factors Pax3 and Pax7 to the forkhead family member FOXO1A. Both eRMS and aRMS tumor cells express myogenic markers such as MyoD, but their ability to complete differentiation is impaired. How this impairment occurs is the subject of this review, which will focus on several themes, including signaling pathways that converge on Pax-forkhead gene targets, alterations in MyoD function, epigenetic modifications of myogenic promoters, and microRNAs whose expression patterns in RMS alter key regulatory circuits to help maintain tumor cells in an opportunistically less differentiated state.
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Affiliation(s)
- Charles Keller
- Pediatric Cancer Biology Program, Papé Family Pediatric Research Institute, Department of Pediatrics, Oregon Health & Science University, Portland, OR, USA
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40
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Stra6, a retinoic acid-responsive gene, participates in p53-induced apoptosis after DNA damage. Cell Death Differ 2013; 20:910-9. [PMID: 23449393 DOI: 10.1038/cdd.2013.14] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Stra6 is the retinoic acid (RA)-inducible gene encoding the cellular receptor for holo-retinol binding protein. This transmembrane protein mediates the internalization of retinol, which then upregulates RA-responsive genes in target cells. Here, we show that Stra6 can be upregulated by DNA damage in a p53-dependent manner, and it has an important role in cell death responses. Stra6 expression induced significant amounts of apoptosis in normal and cancer cells, and it was also able to influence p53-mediated cell fate decisions by turning an initial arrest response into cell death. Moreover, inhibition of Stra6 severely compromised p53-induced apoptosis. We also found that Stra6 induced mitochondria depolarization and accumulation of reactive oxygen species, and that it was present not only at the cellular membrane but also in the cytosol. Finally, we show that these novel functions of Stra6 did not require downstream activation of RA signalling. Our results present a previously unknown link between the RA and p53 pathways and provide a rationale to use retinoids to upregulate Stra6, and thus enhance the tumour suppressor functions of p53. This may have implications for the role of vitamin A metabolites in cancer prevention and treatment.
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Zheng H, Chen L, Pledger WJ, Fang J, Chen J. p53 promotes repair of heterochromatin DNA by regulating JMJD2b and SUV39H1 expression. Oncogene 2013; 33:734-44. [PMID: 23376847 PMCID: PMC3912226 DOI: 10.1038/onc.2013.6] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2012] [Revised: 11/12/2012] [Accepted: 12/09/2012] [Indexed: 12/26/2022]
Abstract
Constitutive heterochromatin is important for maintaining chromosome stability but also delays the repair of DNA double strand breaks (DSB). DSB repair in complex mammalian genomes involves a fast phase (2–6 hrs) where most of the breaks are rapidly repaired, and a slow phase (up to 24 hrs) where the remaining damages in heterochromatin are repaired. We found that p53 deficiency delays the slow phase DNA repair after ionizing irradiation. P53 deficiency prevents down regulation of histone H3K9 trimethylation at pericentric heterochromatin after DNA damage. Moreover, p53 directly induces expression of the H3 K9 demethylase JMJD2b through promoter binding. P53 activation also indirectly down regulates expression of the H3 K9 methytransferase SUV39H1. Depletion of JMJD2b or sustained expression of SUV39H1 delays the repair of heterochromatin DNA and reduces clonogenic survival after ionizing irradiation. The results suggest that by regulating JMJD2b and SUV39H1 expression, p53 not only controls transcription but also promotes heterochromatin relaxation to accelerate a rate-limiting step in the repair of complex genomes.
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Affiliation(s)
- H Zheng
- Molecular Oncology Department, H. Lee Moffitt Cancer Center, Tampa, FL, USA
| | - L Chen
- Molecular Oncology Department, H. Lee Moffitt Cancer Center, Tampa, FL, USA
| | - W J Pledger
- Molecular Oncology Department, H. Lee Moffitt Cancer Center, Tampa, FL, USA
| | - J Fang
- Molecular Oncology Department, H. Lee Moffitt Cancer Center, Tampa, FL, USA
| | - J Chen
- Molecular Oncology Department, H. Lee Moffitt Cancer Center, Tampa, FL, USA
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Abstract
The MDM2 and MDMX (also known as HDMX and MDM4) proteins are deregulated in many human cancers and exert their oncogenic activity predominantly by inhibiting the p53 tumour suppressor. However, the MDM proteins modulate and respond to many other signalling networks in which they are embedded. Recent mechanistic studies and animal models have demonstrated how functional interactions in these networks are crucial for maintaining normal tissue homeostasis, and for determining responses to oncogenic and therapeutic challenges. This Review highlights the progress made and pitfalls encountered as the field continues to search for MDM-targeted antitumour agents.
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Affiliation(s)
- Mark Wade
- Center for Genomic Science of IIT@SEMM, Fondazione Istituto Italiano di Tecnologia, Via Adamello 16, 20139 Milan, Italy
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43
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David R. Keeping p53 targets quiet. Nat Rev Mol Cell Biol 2012. [DOI: 10.1038/nrm3347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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