1
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Xie D, Pei Q, Li J, Wan X, Ye T. Emerging Role of E2F Family in Cancer Stem Cells. Front Oncol 2021; 11:723137. [PMID: 34476219 PMCID: PMC8406691 DOI: 10.3389/fonc.2021.723137] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 07/27/2021] [Indexed: 12/14/2022] Open
Abstract
The E2F family of transcription factors (E2Fs) consist of eight genes in mammals. These genes encode ten proteins that are usually classified as transcriptional activators or transcriptional repressors. E2Fs are important for many cellular processes, from their canonical role in cell cycle regulation to other roles in angiogenesis, the DNA damage response and apoptosis. A growing body of evidence demonstrates that cancer stem cells (CSCs) are key players in tumor development, metastasis, drug resistance and recurrence. This review focuses on the role of E2Fs in CSCs and notes that many signals can regulate the activities of E2Fs, which in turn can transcriptionally regulate many different targets to contribute to various biological characteristics of CSCs, such as proliferation, self-renewal, metastasis, and drug resistance. Therefore, E2Fs may be promising biomarkers and therapeutic targets associated with CSCs pathologies. Finally, exploring therapeutic strategies for E2Fs may result in disruption of CSCs, which may prevent tumor growth, metastasis, and drug resistance.
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Affiliation(s)
- Dan Xie
- Department of Laboratory Medicine, The Affiliated Hospital of Southwest Medical University, Sichuan, China
| | - Qin Pei
- Department of Laboratory Medicine, The Affiliated Hospital of Southwest Medical University, Sichuan, China
| | - Jingyuan Li
- Department of Laboratory Medicine, The Affiliated Hospital of Southwest Medical University, Sichuan, China
| | - Xue Wan
- Department of Laboratory Medicine, The Affiliated Hospital of Southwest Medical University, Sichuan, China
| | - Ting Ye
- Department of Laboratory Medicine, The Affiliated Hospital of Southwest Medical University, Sichuan, China
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2
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MACF1 promotes osteoblast differentiation by sequestering repressors in cytoplasm. Cell Death Differ 2021; 28:2160-2178. [PMID: 33664480 PMCID: PMC8257666 DOI: 10.1038/s41418-021-00744-9] [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: 09/06/2019] [Revised: 01/22/2021] [Accepted: 01/28/2021] [Indexed: 02/07/2023] Open
Abstract
Osteoblast differentiation leading to bone formation requires a coordinated transcriptional program. Osteoblastic cells with low level of microtubule actin crosslinking factor 1 (MACF1) show reduced osteoblast differentiation ability, however, the comprehensive mechanism of MACF1's action remains unexplored. In the current study, we found that MACF1 knockdown suppressed osteoblast differentiation by altering the transcriptome dynamics. We further identified two MACF1-interacted proteins, cyclin-dependent kinase 12 (CDK12) and MYST/Esa1-associated factor 6 (MEAF6), and two MACF1-interacted transcription factors (TFs), transcription factor 12 (TCF12) and E2F transcription factor 6 (E2F6), which repress osteoblast differentiation by altering the expression of osteogenic TFs and genes. Moreover, we found that MACF1 regulated cytoplasmic-nuclear localization of itself, TCF12 and E2F6 in a concentration-dependent manner. MACF1 oppositely regulates the expression of TCF12 and transcription factor 7 (TCF7), two TFs that drive osteoblast differentiation to opposite directions. This study reveals that MACF1, a cytoskeletal protein, acts as a sponge for repressors of osteoblast differentiation to promote osteoblast differentiation and contributes to a novel mechanistic insight of osteoblast differentiation and transcription dynamics.
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3
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Dahlet T, Truss M, Frede U, Al Adhami H, Bardet AF, Dumas M, Vallet J, Chicher J, Hammann P, Kottnik S, Hansen P, Luz U, Alvarez G, Auclair G, Hecht J, Robinson PN, Hagemeier C, Weber M. E2F6 initiates stable epigenetic silencing of germline genes during embryonic development. Nat Commun 2021; 12:3582. [PMID: 34117224 PMCID: PMC8195999 DOI: 10.1038/s41467-021-23596-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 05/04/2021] [Indexed: 11/24/2022] Open
Abstract
In mouse development, long-term silencing by CpG island DNA methylation is specifically targeted to germline genes; however, the molecular mechanisms of this specificity remain unclear. Here, we demonstrate that the transcription factor E2F6, a member of the polycomb repressive complex 1.6 (PRC1.6), is critical to target and initiate epigenetic silencing at germline genes in early embryogenesis. Genome-wide, E2F6 binds preferentially to CpG islands in embryonic cells. E2F6 cooperates with MGA to silence a subgroup of germline genes in mouse embryonic stem cells and in embryos, a function that critically depends on the E2F6 marked box domain. Inactivation of E2f6 leads to a failure to deposit CpG island DNA methylation at these genes during implantation. Furthermore, E2F6 is required to initiate epigenetic silencing in early embryonic cells but becomes dispensable for the maintenance in differentiated cells. Our findings elucidate the mechanisms of epigenetic targeting of germline genes and provide a paradigm for how transient repression signals by DNA-binding factors in early embryonic cells are translated into long-term epigenetic silencing during mouse development. DNA methylation targets CpG island promoters of germline genes to repress their expression in mouse somatic cells. Here the authors show that a transcription factor E2F6 is required to target CpG island DNA methylation and epigenetic silencing to germline genes during early mouse development.
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Affiliation(s)
- Thomas Dahlet
- University of Strasbourg, Strasbourg, France.,CNRS UMR7242, Biotechnology and Cell Signaling, Illkirch, France
| | - Matthias Truss
- Pediatric Oncology, Labor für Pädiatrische Molekularbiologie, Charité - Universitätsmedizin Berlin, Berlin, Germany.
| | - Ute Frede
- Pediatric Oncology, Labor für Pädiatrische Molekularbiologie, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Hala Al Adhami
- University of Strasbourg, Strasbourg, France.,CNRS UMR7242, Biotechnology and Cell Signaling, Illkirch, France
| | - Anaïs F Bardet
- University of Strasbourg, Strasbourg, France.,CNRS UMR7242, Biotechnology and Cell Signaling, Illkirch, France
| | - Michael Dumas
- University of Strasbourg, Strasbourg, France.,CNRS UMR7242, Biotechnology and Cell Signaling, Illkirch, France
| | - Judith Vallet
- University of Strasbourg, Strasbourg, France.,CNRS UMR7242, Biotechnology and Cell Signaling, Illkirch, France
| | - Johana Chicher
- Plateforme protéomique Strasbourg Esplanade, CNRS, University of Strasbourg, Strasbourg, France
| | - Philippe Hammann
- Plateforme protéomique Strasbourg Esplanade, CNRS, University of Strasbourg, Strasbourg, France
| | - Sarah Kottnik
- Pediatric Oncology, Labor für Pädiatrische Molekularbiologie, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Peter Hansen
- Berlin Brandenburg Center for Regenerative Therapies (BCRT), Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Uschi Luz
- Pediatric Oncology, Labor für Pädiatrische Molekularbiologie, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Gonzalo Alvarez
- Pediatric Oncology, Labor für Pädiatrische Molekularbiologie, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Ghislain Auclair
- University of Strasbourg, Strasbourg, France.,CNRS UMR7242, Biotechnology and Cell Signaling, Illkirch, France
| | - Jochen Hecht
- Berlin Brandenburg Center for Regenerative Therapies (BCRT), Charité Universitätsmedizin Berlin, Berlin, Germany.,Centre for Genomic Regulation, Barcelona, Spain
| | - Peter N Robinson
- Berlin Brandenburg Center for Regenerative Therapies (BCRT), Charité Universitätsmedizin Berlin, Berlin, Germany.,Jackson Laboratory for Genomic Medicine, Farmington, CT, USA
| | - Christian Hagemeier
- Pediatric Oncology, Labor für Pädiatrische Molekularbiologie, Charité - Universitätsmedizin Berlin, Berlin, Germany.
| | - Michael Weber
- University of Strasbourg, Strasbourg, France. .,CNRS UMR7242, Biotechnology and Cell Signaling, Illkirch, France.
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4
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mRNA and miRNA Expression Analyses of the MYC/ E2F/miR-17-92 Network in the Most Common Pediatric Brain Tumors. Int J Mol Sci 2021; 22:ijms22020543. [PMID: 33430425 PMCID: PMC7827072 DOI: 10.3390/ijms22020543] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 12/30/2020] [Accepted: 01/04/2021] [Indexed: 12/25/2022] Open
Abstract
Numerous molecular factors disrupt the correctness of the cell cycle process leading to the development of cancer due to increased cell proliferation. Among known causative factors of such process is abnormal gene expression. Nowadays in the light of current knowledge such alterations are frequently considered in the context of mRNA–miRNA correlation. One of the molecular factors with potential value in tumorigenesis is the feedback loop between MYC and E2F genes in which miR-17-5p and miR-20a from the miR-17-92 cluster are involved. The current literature shows that overexpression of the members of the OncomiR-1 are involved in the development of many solid tumors. In the present work, we investigated the expression of components of the MYC/E2F/miR-17-92 network and their closely related elements including members of MYC and E2F families and miRNAs from two paralogs of miR-17-92: miR-106b-25 and miR-106a-363, in the most common brain tumors of childhood, pilocytic astrocytoma (PA), WHO grade 1; ependymoma (EP), WHO grade 2; and medulloblastoma (MB), WHO grade 4. We showed that the highest gene expression was observed in the MYC family for MYCN and in the E2F family for E2F2. Positive correlation was observed between the gene expression and tumor grade and type, with the highest expression being noted for medulloblastomas, followed by ependymomas, and the lowest for pilocytic astrocytomas. Most members of miR-17-92, miR-106a-363 and miR-106b-25 clusters were upregulated and the highest expression was noted for miR-18a and miR-18b. The rest of the miRNAs, including miR-19a, miR-92a, miR-106a, miR-93, or miR-25 also showed high values. miR-17-5p, miR-20a obtained a high level of expression in medulloblastomas and ependymomas, while close to the control in the pilocytic astrocytoma samples. miRNA expression also depended on tumor grade and histology.
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5
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Epstein-Barr Virus Facilitates Expression of KLF14 by Regulating the Cooperative Binding of the E2F-Rb-HDAC Complex in Latent Infection. J Virol 2020; 94:JVI.01209-20. [PMID: 32847849 DOI: 10.1128/jvi.01209-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 08/23/2020] [Indexed: 12/31/2022] Open
Abstract
Epstein-Barr virus (EBV) was discovered as the first human tumor virus more than 50 years ago. EBV infects more than 90% of the human population worldwide and is associated with numerous hematologic malignancies and epithelial malignancies. EBV establishes latent infection in B cells, which is the typical program seen in lymphomagenesis. Understanding EBV-mediated transcription regulatory networks is one of the current challenges that will uncover new insights into the mechanism of viral-mediated lymphomagenesis. Here, we describe the regulatory profiles of several cellular factors (E2F6, E2F1, Rb, HDAC1, and HDAC2) together with EBV latent nuclear antigens using next-generation sequencing (NGS) analysis. Our results show that the E2F-Rb-HDAC complex exhibits similar distributions in genomic regions of EBV-positive cells and is associated with oncogenic super-enhancers involving long-range regulatory regions. Furthermore, EBV latent antigens cooperatively hijack this complex to bind at KLFs gene loci and facilitate KLF14 gene expression in lymphoblastoid cell lines (LCLs). These results demonstrate that EBV latent antigens can function as master regulators of this multisubunit repressor complex (E2F-Rb-HDAC) to reverse its suppressive activities and facilitate downstream gene expression that can contribute to viral-induced lymphomagenesis. These results provide novel insights into targets for the development of new therapeutic interventions for treating EBV-associated lymphomas.IMPORTANCE Epstein-Barr virus (EBV), as the first human tumor virus, infects more than 90% of the human population worldwide and is associated with numerous human cancers. Exploring EBV-mediated transcription regulatory networks is critical to understand viral-associated lymphomagenesis. However, the detailed mechanism is not fully explored. Now we describe the regulatory profiles of the E2F-Rb-HDAC complex together with EBV latent antigens, and we found that EBV latent antigens cooperatively facilitate KLF14 expression by antagonizing this multisubunit repressor complex in EBV-positive cells. This provides potential therapeutic targets for the treatment of EBV-associated cancers.
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6
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Evolving Role of RING1 and YY1 Binding Protein in the Regulation of Germ-Cell-Specific Transcription. Genes (Basel) 2019; 10:genes10110941. [PMID: 31752312 PMCID: PMC6895862 DOI: 10.3390/genes10110941] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Revised: 11/07/2019] [Accepted: 11/14/2019] [Indexed: 12/11/2022] Open
Abstract
Separation of germline cells from somatic lineages is one of the earliest decisions of embryogenesis. Genes expressed in germline cells include apoptotic and meiotic factors, which are not transcribed in the soma normally, but a number of testis-specific genes are active in numerous cancer types. During germ cell development, germ-cell-specific genes can be regulated by specific transcription factors, retinoic acid signaling and multimeric protein complexes. Non-canonical polycomb repressive complexes, like ncPRC1.6, play a critical role in the regulation of the activity of germ-cell-specific genes. RING1 and YY1 binding protein (RYBP) is one of the core members of the ncPRC1.6. Surprisingly, the role of Rybp in germ cell differentiation has not been defined yet. This review is focusing on the possible role of Rybp in this process. By analyzing whole-genome transcriptome alterations of the Rybp-/- embryonic stem (ES) cells and correlating this data with experimentally identified binding sites of ncPRC1.6 subunits and retinoic acid receptors in ES cells, we propose a model how germ-cell-specific transcription can be governed by an RYBP centered regulatory network, underlining the possible role of RYBP in germ cell differentiation and tumorigenesis.
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7
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Lafta IJ. E2F6 is essential for cell viability in breast cancer cells during replication stress. ACTA ACUST UNITED AC 2019; 43:293-304. [PMID: 31768102 PMCID: PMC6823915 DOI: 10.3906/biy-1905-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
E2F6 is a member of the E2F family of transcription factors involved in regulation of a wide variety of genes through both activation and repression. E2F6 has been reported as overexpressed in breast cancers but whether or not this is important for tumor development is unclear. We first checked E2F6 expression in tumor cDNAs and the protein level in a range of breast cancer cell lines. RNA interference-mediated depletion was then used to assess the importance of E2F6 expression in cell lines with regard to cell cycle profile using fluorescence-activated cell sorting and a cell survival assay using (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). The overexpression of E2F6 was confirmed in breast tumor cDNA samples and breast cancer cell lines. Depletion of E2F6 in the breast cancer cells reduced cell viability in MCF-7, T-47D, and MDA-MB-231 cells. There was little effect in the nontumor breast cell line MCF-10A. The deleterious effect on cancer cells was greater during replication stress, leading to an increase in the proportion of breast cancer cells with sub-G1 DNA content. These results suggest that E2F6 might be essential for the survival of breast cancer cells experiencing replication stress, and therefore it could be a target for combined therapy.
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Affiliation(s)
- Inam Jasim Lafta
- Department of Microbiology, College of Veterinary Medicine, University of Baghdad, Baghdad, Iraq
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8
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Lukoseviciute M, Gavriouchkina D, Williams RM, Hochgreb-Hagele T, Senanayake U, Chong-Morrison V, Thongjuea S, Repapi E, Mead A, Sauka-Spengler T. From Pioneer to Repressor: Bimodal foxd3 Activity Dynamically Remodels Neural Crest Regulatory Landscape In Vivo. Dev Cell 2019; 47:608-628.e6. [PMID: 30513303 PMCID: PMC6286384 DOI: 10.1016/j.devcel.2018.11.009] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 08/15/2018] [Accepted: 10/31/2018] [Indexed: 02/06/2023]
Abstract
The neural crest (NC) is a transient embryonic stem cell-like population characterized by its multipotency and broad developmental potential. Here, we perform NC-specific transcriptional and epigenomic profiling of foxd3-mutant cells in vivo to define the gene regulatory circuits controlling NC specification. Together with global binding analysis obtained by foxd3 biotin-ChIP and single cell profiles of foxd3-expressing premigratory NC, our analysis shows that, during early steps of NC formation, foxd3 acts globally as a pioneer factor to prime the onset of genes regulating NC specification and migration by re-arranging the chromatin landscape, opening cis-regulatory elements and reshuffling nucleosomes. Strikingly, foxd3 then gradually switches from an activator to its well-described role as a transcriptional repressor and potentially uses differential partners for each role. Taken together, these results demonstrate that foxd3 acts bimodally in the neural crest as a switch from “permissive” to “repressive” nucleosome and chromatin organization to maintain multipotency and define cell fates. FoxD3 primes neural crest specification by modulating distal enhancers FoxD3 represses a number of neural crest migration and differentiation genes In neural crest, FoxD3 acts to switch chromatin from “permissive” to “repressive” Distinctive gene regulatory mechanisms underlie the bimodal action of FoxD3
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Affiliation(s)
- Martyna Lukoseviciute
- Radcliffe Department of Medicine, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Daria Gavriouchkina
- Radcliffe Department of Medicine, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Ruth M Williams
- Radcliffe Department of Medicine, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Tatiana Hochgreb-Hagele
- Radcliffe Department of Medicine, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Upeka Senanayake
- Radcliffe Department of Medicine, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Vanessa Chong-Morrison
- Radcliffe Department of Medicine, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Supat Thongjuea
- Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Emmanouela Repapi
- MRC WIMM Centre for Computational Biology Research Group, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Adam Mead
- Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK
| | - Tatjana Sauka-Spengler
- Radcliffe Department of Medicine, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX3 9DS, UK.
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9
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Cheng FHC, Lin HY, Hwang TW, Chen YC, Huang RL, Chang CB, Yang W, Lin RI, Lin CW, Chen GCW, Mai SY, Lin JMJ, Chuang YM, Chou JL, Kuo LW, Li C, Cheng ASL, Lai HC, Wu SF, Tsai JC, Chan MWY. E2F6 functions as a competing endogenous RNA, and transcriptional repressor, to promote ovarian cancer stemness. Cancer Sci 2019; 110:1085-1095. [PMID: 30582655 PMCID: PMC6398890 DOI: 10.1111/cas.13920] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 12/17/2018] [Accepted: 12/19/2018] [Indexed: 12/20/2022] Open
Abstract
Ovarian cancer is the most lethal cancer of the female reproductive system. In that regard, several epidemiological studies suggest that long‐term exposure to estrogen could increase ovarian cancer risk, although its precise role remains controversial. To decipher a mechanism for this, we previously generated a mathematical model of how estrogen‐mediated upregulation of the transcription factor, E2F6, upregulates the ovarian cancer stem/initiating cell marker, c‐Kit, by epigenetic silencing the tumor suppressor miR‐193a, and a competing endogenous (ceRNA) mechanism. In this study, we tested that previous mathematical model, showing that estrogen treatment of immortalized ovarian surface epithelial cells upregulated both E2F6 and c‐KIT, but downregulated miR‐193a. Luciferase assays further confirmed that microRNA‐193a targets both E2F6 and c‐Kit. Interestingly, ChIP‐PCR and bisulphite pyrosequencing showed that E2F6 also epigenetically suppresses miR‐193a, through recruitment of EZH2, and by a complex ceRNA mechanism in ovarian cancer cell lines. Importantly, cell line and animal experiments both confirmed that E2F6 promotes ovarian cancer stemness, whereas E2F6 or EZH2 depletion derepressed miR‐193a, which opposes cancer stemness, by alleviating DNA methylation and repressive chromatin. Finally, 118 ovarian cancer patients with miR‐193a promoter hypermethylation had poorer survival than those without hypermethylation. These results suggest that an estrogen‐mediated E2F6 ceRNA network epigenetically and competitively inhibits microRNA‐193a activity, promoting ovarian cancer stemness and tumorigenesis.
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Affiliation(s)
- Frank H C Cheng
- Department of Biomedical Sciences, National Chung Cheng University, Chia-Yi, Taiwan.,Epigenomics and Human Disease Research Center, National Chung Cheng University, Chia-Yi, Taiwan
| | - Hon-Yi Lin
- Department of Radiation Oncology, Buddhist Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chia-Yi, Taiwan.,School of Medicine, Tzu Chi University, Hualien, Taiwan
| | - Tzy-Wei Hwang
- Department of Mathematics, National Chung Cheng University, Chia-Yi, Taiwan
| | - Yin-Chen Chen
- Department of Biomedical Sciences, National Chung Cheng University, Chia-Yi, Taiwan.,Epigenomics and Human Disease Research Center, National Chung Cheng University, Chia-Yi, Taiwan
| | - Rui-Lan Huang
- Department of Obstetrics and Gynecology, School of Medicine, College of Medicine and Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan
| | - Chia-Bin Chang
- Department of Biomedical Sciences, National Chung Cheng University, Chia-Yi, Taiwan.,Epigenomics and Human Disease Research Center, National Chung Cheng University, Chia-Yi, Taiwan
| | - Weiqin Yang
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Ru-Inn Lin
- Department of Radiation Oncology, Buddhist Dalin Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Chia-Yi, Taiwan
| | - Ching-Wen Lin
- Department of Biomedical Sciences, National Chung Cheng University, Chia-Yi, Taiwan.,Epigenomics and Human Disease Research Center, National Chung Cheng University, Chia-Yi, Taiwan
| | - Gary C W Chen
- Department of Biomedical Sciences, National Chung Cheng University, Chia-Yi, Taiwan.,Epigenomics and Human Disease Research Center, National Chung Cheng University, Chia-Yi, Taiwan
| | - Shu-Yuan Mai
- Department of Biomedical Sciences, National Chung Cheng University, Chia-Yi, Taiwan
| | - Jora M J Lin
- Department of Biomedical Sciences, National Chung Cheng University, Chia-Yi, Taiwan.,Epigenomics and Human Disease Research Center, National Chung Cheng University, Chia-Yi, Taiwan
| | - Yu-Ming Chuang
- Department of Biomedical Sciences, National Chung Cheng University, Chia-Yi, Taiwan.,Epigenomics and Human Disease Research Center, National Chung Cheng University, Chia-Yi, Taiwan
| | - Jian-Liang Chou
- Department of Biomedical Sciences, National Chung Cheng University, Chia-Yi, Taiwan.,Epigenomics and Human Disease Research Center, National Chung Cheng University, Chia-Yi, Taiwan
| | - Li-Wei Kuo
- Department of Biomedical Sciences, National Chung Cheng University, Chia-Yi, Taiwan.,Epigenomics and Human Disease Research Center, National Chung Cheng University, Chia-Yi, Taiwan
| | - Chin Li
- Department of Biomedical Sciences, National Chung Cheng University, Chia-Yi, Taiwan
| | - Alfred S L Cheng
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Hung-Cheng Lai
- Department of Obstetrics and Gynecology, School of Medicine, College of Medicine and Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan
| | - Shu-Fen Wu
- Department of Biomedical Sciences, National Chung Cheng University, Chia-Yi, Taiwan.,Epigenomics and Human Disease Research Center, National Chung Cheng University, Chia-Yi, Taiwan
| | - Je-Chiang Tsai
- Department of Mathematics, National Tsing Hua University, Hsin-Chu, Taiwan
| | - Michael W Y Chan
- Department of Biomedical Sciences, National Chung Cheng University, Chia-Yi, Taiwan.,Epigenomics and Human Disease Research Center, National Chung Cheng University, Chia-Yi, Taiwan.,Center for Innovative Research on Aging Society (CIRAS), National Chung Cheng University, Chia-Yi, Taiwan.,Research Center for Environmental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
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10
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Li Y, Huang J, Yang D, Xiang S, Sun J, Li H, Ren G. Expression patterns of E2F transcription factors and their potential prognostic roles in breast cancer. Oncol Lett 2018; 15:9216-9230. [PMID: 29844824 PMCID: PMC5958806 DOI: 10.3892/ol.2018.8514] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 03/01/2018] [Indexed: 11/12/2022] Open
Abstract
E2Fs, as a family of pivotal transcription factors, have been implicated in multiple biological functions in human cancer; however, the expression and prognostic significance of E2Fs in breast cancer remains unknown. In the present study, the mRNA expression patterns of E2Fs in breast cancer were investigated with Oncomine and The Cancer Genome Atlas data. Prognostic values of E2Fs for patients with breast cancer were determined using the Kaplan-Meier plotter database. The results strongly indicated that E2F1, E2F2, E2F3, E2F5, E2F7 and E2F8 were overexpressed in patients with breast cancer, whereas E2F4 and E2F6 exhibited no expression difference between patients with cancer and healthy controls. In survival analyses, elevated E2F1, E2F3, E2F5, E2F7 and E2F8 expression levels were significantly associated with lower overall survival, relapse-free survival (RFS), distant metastasis-free survival (DMFS) or post-progression survival for patients with breast cancer. Furthermore, high expression of E2F4 indicated improved RFS but reduced DMFS. Subgroup analyses based on four clinicopathological factors further revealed that E2Fs were associated with the prognosis of patients with breast cancer in an estrogen receptor-, progesterone receptor-, human epidermal growth factor 2- and lymph node status-specific manner. These data indicated that E2Fs may serve as promising biomarkers and therapeutic targets for breast cancer.
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Affiliation(s)
- Yunhai Li
- Chongqing Key Laboratory of Molecular Oncology and Epigenetics, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China.,Department of Endocrine and Breast Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China
| | - Jing Huang
- Department of Pneumology Medicine, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China
| | - Dejuan Yang
- Chongqing Key Laboratory of Molecular Oncology and Epigenetics, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China.,Department of Endocrine and Breast Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China
| | - Shili Xiang
- Chongqing Key Laboratory of Molecular Oncology and Epigenetics, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China
| | - Jiazheng Sun
- Chongqing Key Laboratory of Molecular Oncology and Epigenetics, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China
| | - Hongzhong Li
- Chongqing Key Laboratory of Molecular Oncology and Epigenetics, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China.,Department of Endocrine and Breast Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China
| | - Guosheng Ren
- Chongqing Key Laboratory of Molecular Oncology and Epigenetics, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China.,Department of Endocrine and Breast Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, P.R. China
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11
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Nagaprashantha LD, Singhal J, Li H, Warden C, Liu X, Horne D, Awasthi S, Salgia R, Singhal SS. 2'-Hydroxyflavanone effectively targets RLIP76-mediated drug transport and regulates critical signaling networks in breast cancer. Oncotarget 2018; 9:18053-18068. [PMID: 29719590 PMCID: PMC5915057 DOI: 10.18632/oncotarget.24720] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 03/06/2018] [Indexed: 11/25/2022] Open
Abstract
Breast cancer (BC) is the most common cancer in women. Estrogen, epidermal growth factor receptor 2 (ERBB2, HER2), and oxidative stress represent critical mechanistic nodes associated with BC. RLIP76 is a major mercapturic acid pathway transporter whose expression is increased in BC. In the quest of a novel molecule with chemopreventive and chemotherapeutic potential, we evaluated the effects of 2'-Hydroxyflavanone (2HF) in BC. 2HF enhanced the inhibitory effects of RLIP76 depletion and also inhibited RLIP76-mediated doxorubicin transport in BC cells. RNA-sequencing revealed that 2HF induces strong reversal of the gene expression pattern in ER+MCF7, HER2+ SKBR3 and triple-negative MDA-MB-231 BC cells with minimal effects on MCF10A normal breast epithelial cells. 2HF down regulated ERα and enhanced inhibitory effects of imatinib mesylate/Gleevec in MCF7 cells. 2HF also down regulated ERα and HER2 gene networks in MCF7 and SKBR3 cells, respectively. 2HF activated TP53 and inhibited TGFβ1 canonical pathway in MCF7 and MDA-MB-231 BC cells. 2HF also regulated the expression of a number of critical prognostic genes of MammaPrint panel and their upstream targets including TP53, CDKN2A and MYC. The collective findings from this study provide a comprehensive, direct and integrated evidence for the benefits of 2HF in targeting major and clinically relevant mechanistic regulators of BC.
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Affiliation(s)
- Lokesh Dalasanur Nagaprashantha
- Department of Medical Oncology, Beckman Research Institute of City of Hope, Comprehensive Cancer Center and National Medical Center, Duarte, CA 91010, USA
| | - Jyotsana Singhal
- Department of Medical Oncology, Beckman Research Institute of City of Hope, Comprehensive Cancer Center and National Medical Center, Duarte, CA 91010, USA.,Department of Molecular Medicine, Beckman Research Institute of City of Hope, Comprehensive Cancer Center and National Medical Center, Duarte, CA 91010, USA
| | - Hongzhi Li
- Department of Computational Therapeutics, Beckman Research Institute of City of Hope, Comprehensive Cancer Center and National Medical Center, Duarte, CA 91010, USA
| | - Charles Warden
- Department of Genomic Core, Beckman Research Institute of City of Hope, Comprehensive Cancer Center and National Medical Center, Duarte, CA 91010, USA
| | - Xueli Liu
- Department of Information Sciences & Biostatistics, Beckman Research Institute of City of Hope, Comprehensive Cancer Center and National Medical Center, Duarte, CA 91010, USA
| | - David Horne
- Department of Molecular Medicine, Beckman Research Institute of City of Hope, Comprehensive Cancer Center and National Medical Center, Duarte, CA 91010, USA
| | - Sanjay Awasthi
- Department of Internal Medicine, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA
| | - Ravi Salgia
- Department of Medical Oncology, Beckman Research Institute of City of Hope, Comprehensive Cancer Center and National Medical Center, Duarte, CA 91010, USA
| | - Sharad S Singhal
- Department of Medical Oncology, Beckman Research Institute of City of Hope, Comprehensive Cancer Center and National Medical Center, Duarte, CA 91010, USA
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12
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Costa C, Santos M, Martínez-Fernández M, Lorz C, Lázaro S, Paramio JM. Deregulation of the pRb-E2F4 axis alters epidermal homeostasis and favors tumor development. Oncotarget 2018; 7:75712-75728. [PMID: 27708231 PMCID: PMC5342772 DOI: 10.18632/oncotarget.12362] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Accepted: 09/19/2016] [Indexed: 11/25/2022] Open
Abstract
E2F/RB activity is altered in most human tumors. The retinoblastoma family of proteins plays a key role in regulating the progression of the cell cycle from the G1 to S phases. This is achieved through negative regulation of E2F transcription factors, important positive regulators of cell cycle entry. E2F family members are divided into two groups: activators (E2F1-E2F3a) and repressors (E2F3b-E2F8). E2F4 accounts for a large part of the E2F activity and is a main E2F repressor member in vivo. Perturbations in the balance from quiescence towards proliferation contribute to increased mitotic gene expression levels frequently observed in cancer. We have previously reported that combined Rb1-Rbl1 or Rb1-E2f1 ablation in epidermis produces important alterations in epidermal proliferation and differentiation, leading to tumor development. However, the possible roles of E2F4 in this context are still to be determined. Here, we show the absence of any discernible phenotype in the skin of mice lacking of E2f4. In contrast, the inducible loss of Rb1 in the epidermis of E2F4-null mice produced multiple skin abnormalities including altered differentiation and proliferation, spontaneous wounds, carcinoma in situ development and stem cell perturbations. All these phenotypic alterations are associated with extensive gene expression changes, the induction of c-myc and the Akt activation. Moreover the whole transcriptome analyses in comparison with previous models generated also revealed extensive changes in multiple repressive complexes and in transcription factor activity. These results point to E2F4 as a master regulator in multiple steps of epidermal homeostasis in Rb1 absence.
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Affiliation(s)
- Clotilde Costa
- Unidad de Oncología Molecular, CIEMAT (ed70A), 28040 Madrid, Spain.,Present address: Unidad Mixta Roche-Chus, Hospital Universitario, 15706 Santiago de Compostela, Spain
| | - Mirentxu Santos
- Unidad de Oncología Molecular, CIEMAT (ed70A), 28040 Madrid, Spain.,Unidad de Oncología Molecular y Celular, Instituto de Investigaciones Biomed, Hospital Universitario 12 de Octubre, 28041 Madrid, Spain
| | - Mónica Martínez-Fernández
- Unidad de Oncología Molecular, CIEMAT (ed70A), 28040 Madrid, Spain.,Unidad de Oncología Molecular y Celular, Instituto de Investigaciones Biomed, Hospital Universitario 12 de Octubre, 28041 Madrid, Spain
| | - Corina Lorz
- Unidad de Oncología Molecular, CIEMAT (ed70A), 28040 Madrid, Spain.,Unidad de Oncología Molecular y Celular, Instituto de Investigaciones Biomed, Hospital Universitario 12 de Octubre, 28041 Madrid, Spain
| | - Sara Lázaro
- Unidad de Oncología Molecular, CIEMAT (ed70A), 28040 Madrid, Spain
| | - Jesús M Paramio
- Unidad de Oncología Molecular, CIEMAT (ed70A), 28040 Madrid, Spain.,Unidad de Oncología Molecular y Celular, Instituto de Investigaciones Biomed, Hospital Universitario 12 de Octubre, 28041 Madrid, Spain
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13
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Zhan S, Wang T, Ge W, Li J. Multiple roles of Ring 1 and YY1 binding protein in physiology and disease. J Cell Mol Med 2018; 22:2046-2054. [PMID: 29383875 PMCID: PMC5867070 DOI: 10.1111/jcmm.13503] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 11/16/2017] [Indexed: 12/17/2022] Open
Abstract
Ring 1 and YY1 binding protein (RYBP) was first identified in 1999, and its structure includes a conserved Npl4 Zinc finger motif at the N‐terminus, a central region that is characteristically enriched with arginine and lysine residues and a C‐terminal region enriched with serine and threonine amino acids. Over nearly 20 years, multiple studies have found that RYBP functions as an organ developmental adaptor. There is also evidence that RYBP regulates the expression of different genes involved in various aspects of biological processes, via a mechanism that is dependent on interactions with components of PcG complexes and/or through binding to different transcriptional factors. In addition, RYBP interacts directly or indirectly with apoptosis‐associated proteins to mediate anti‐apoptotic or pro‐apoptotic activity in both the cytoplasm and nucleus of various cell types. Furthermore, RYBP has also been shown to act as tumour suppressor gene in different solid tumours, but as an oncogene in lymphoma and melanoma. In this review, we summarize our current understanding of the functions of this multifaceted RYBP in physiological and pathological conditions, including embryonic development, apoptosis and cancer, as well as its role as a component of polycomb repressive complex 1.
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Affiliation(s)
- Shaohua Zhan
- National Center for Clinical Laboratories, Beijing Hospital, National Center of Gerontology, Beijing, China.,National Key Laboratory of Medical Molecular Biology & Department of Immunology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Beijing, China
| | - Tianxiao Wang
- Key Laboratory of Carcinogenesis and Translational Research, Department of Head and Neck Surgery, Peking University Cancer Hospital & Institute, Beijing, China
| | - Wei Ge
- National Key Laboratory of Medical Molecular Biology & Department of Immunology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences, Beijing, China
| | - Jinming Li
- National Center for Clinical Laboratories, Beijing Hospital, National Center of Gerontology, Beijing, China
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14
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Samd7 is a cell type-specific PRC1 component essential for establishing retinal rod photoreceptor identity. Proc Natl Acad Sci U S A 2017; 114:E8264-E8273. [PMID: 28900001 DOI: 10.1073/pnas.1707021114] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Precise transcriptional regulation controlled by a transcription factor network is known to be crucial for establishing correct neuronal cell identities and functions in the CNS. In the retina, the expression of various cone and rod photoreceptor cell genes is regulated by multiple transcription factors; however, the role of epigenetic regulation in photoreceptor cell gene expression has been poorly understood. Here, we found that Samd7, a rod-enriched sterile alpha domain (SAM) domain protein, is essential for silencing nonrod gene expression through H3K27me3 regulation in rod photoreceptor cells. Samd7-null mutant mice showed ectopic expression of nonrod genes including S-opsin in rod photoreceptor cells and rod photoreceptor cell dysfunction. Samd7 physically interacts with Polyhomeotic homologs (Phc proteins), components of the Polycomb repressive complex 1 (PRC1), and colocalizes with Phc2 and Ring1B in Polycomb bodies. ChIP assays showed a significant decrease of H3K27me3 in the genes up-regulated in the Samd7-deficient retina, showing that Samd7 deficiency causes the derepression of nonrod gene expression in rod photoreceptor cells. The current study suggests that Samd7 is a cell type-specific PRC1 component epigenetically defining rod photoreceptor cell identity.
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15
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Kenny TC, Schmidt H, Adelson K, Hoshida Y, Koh AP, Shah N, Mandeli J, Ting J, Germain D. Patient-derived Interstitial Fluids and Predisposition to Aggressive Sporadic Breast Cancer through Collagen Remodeling and Inactivation of p53. Clin Cancer Res 2017. [PMID: 28630214 DOI: 10.1158/1078-0432.ccr-17-0342] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Purpose: Despite the fact that interstitial fluid (IF) represents a third of our body fluid, it is the most poorly understood body fluid in medicine. Increased IF pressure is thought to result from the increased deposition of extracellular matrix in the affected tissue preventing its reabsorption. In the cancer field, increased rigidity surrounding a cancerous mass remains the main reason that palpation and radiologic examination, such as mammography, are used for cancer detection. While the pressure produced by IF has been considered, the biochemical composition of IF has not been considered in its effect on tumors.Experimental Design: We classified 135 IF samples from bilateral mastectomy patients based on their ability to promote the invasion of breast cancer cells.Results: We observed a wide range of invasion scores. Patients with high-grade primary tumors at diagnosis had higher IF invasion scores. In mice, injections of high-score IF (IFHigh) in a normal mammary gland promotes ductal hyperplasia, increased collagen deposition, and local invasion. In a mouse model of residual disease, IFHigh increased disease progression and promoted aggressive visceral metastases. Mechanistically, we found that IFHigh induces myofibroblast differentiation and collagen production through activation of CLIC4. IFHigh also downregulates RYBP, leading to degradation of p53. Furthermore, in mammary glands of heterozygous p53-mutant knock-in mice, IFHigh promotes spontaneous tumor formation.Conclusions: Our study indicates that IF can increase the deposition of extracellular matrix and raises the provocative possibility that they play an active role in the predisposition, development, and clinical course of sporadic breast cancers. Clin Cancer Res; 23(18); 5446-59. ©2017 AACR.
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Affiliation(s)
- Timothy C Kenny
- Tisch Cancer Institute, Division of Hematology and Medical Oncology of the Icahn School of Medicine at Mount Sinai, New York, New York
| | - Hank Schmidt
- Tisch Cancer Institute, Dubin Breast Center of the Icahn School of Medicine at Mount Sinai, New York, New York.,Tisch Cancer Institute, Department of Surgery of the Icahn School of Medicine at Mount Sinai, New York, New York
| | - Kerin Adelson
- Tisch Cancer Institute, Dubin Breast Center of the Icahn School of Medicine at Mount Sinai, New York, New York
| | - Yujin Hoshida
- Tisch Cancer Institute, Department of Medicine of the Icahn School of Medicine at Mount Sinai, New York, New York
| | - Anna P Koh
- Tisch Cancer Institute, Department of Medicine of the Icahn School of Medicine at Mount Sinai, New York, New York
| | - Nagma Shah
- Tisch Cancer Institute, Division of Hematology and Medical Oncology of the Icahn School of Medicine at Mount Sinai, New York, New York
| | - John Mandeli
- Department of Biostatistics of the Icahn School of Medicine at Mount Sinai, New York, New York
| | - Jess Ting
- Tisch Cancer Institute, Department of Surgery of the Icahn School of Medicine at Mount Sinai, New York, New York
| | - Doris Germain
- Tisch Cancer Institute, Division of Hematology and Medical Oncology of the Icahn School of Medicine at Mount Sinai, New York, New York.
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16
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Major JL, Dewan A, Salih M, Leddy JJ, Tuana BS. E2F6 Impairs Glycolysis and Activates BDH1 Expression Prior to Dilated Cardiomyopathy. PLoS One 2017; 12:e0170066. [PMID: 28085920 PMCID: PMC5234782 DOI: 10.1371/journal.pone.0170066] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 12/28/2016] [Indexed: 01/07/2023] Open
Abstract
Rationale The E2F pathway plays a critical role in cardiac growth and development, yet its role in cardiac metabolism remains to be defined. Metabolic changes play important roles in human heart failure and studies imply the ketogenic enzyme β-hydroxybutyrate dehydrogenase I (BDH1) is a potential biomarker. Objective To define the role of the E2F pathway in cardiac metabolism and dilated cardiomyopathy (DCM) with a focus on BDH1. Methods and Results We previously developed transgenic (Tg) mice expressing the transcriptional repressor, E2F6, to interfere with the E2F/Rb pathway in post-natal myocardium. These Tg mice present with an E2F6 dose dependent DCM and deregulated connexin-43 (CX-43) levels in myocardium. Using the Seahorse platform, a 22% decrease in glycolysis was noted in neonatal cardiomyocytes isolated from E2F6-Tg hearts. This was associated with a 39% reduction in the glucose transporter GLUT4 and 50% less activation of the regulator of glucose metabolism AKT2. The specific reduction of cyclin B1 (70%) in Tg myocardium implicates its importance in supporting glycolysis in the postnatal heart. No changes in cyclin D expression (known to regulate mitochondrial activity) were noted and lipid metabolism remained unchanged in neonatal cardiomyocytes from Tg hearts. However, E2F6 induced a 40-fold increase of the Bdh1 transcript and 890% increase in its protein levels in hearts from Tg pups implying a potential impact on ketolysis. By contrast, BDH1 expression is not activated until adulthood in normal myocardium. Neonatal cardiomyocytes from Wt hearts incubated with the ketone β-hydroxybutyrate (β-OHB) showed a 100% increase in CX-43 protein levels, implying a role for ketone signaling in gap junction biology. Neonatal cardiomyocyte cultures from Tg hearts exhibited enhanced levels of BDH1 and CX-43 and were not responsive to β-OHB. Conclusions The data reveal a novel role for the E2F pathway in regulating glycolysis in the developing myocardium through a mechanism involving cyclin B1. We reveal BDH1 expression as an early biomarker of heart failure and its potential impact, through ketone signaling, on CX-43 levels in E2F6-induced DCM.
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Affiliation(s)
| | - Aaraf Dewan
- University of Ottawa, Dept. CMM, Ottawa, Ontario, Canada
| | - Maysoon Salih
- University of Ottawa, Dept. CMM, Ottawa, Ontario, Canada
| | - John J. Leddy
- University of Ottawa, Dept. CMM, Ottawa, Ontario, Canada
| | - Balwant S. Tuana
- University of Ottawa, Dept. CMM, Ottawa, Ontario, Canada
- University of Ottawa Heart Institute, Ottawa, Ontario, Canada
- * E-mail:
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17
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Zhao Q, Cai W, Zhang X, Tian S, Zhang J, Li H, Hou C, Ma X, Chen H, Huang B, Chen D. RYBP Expression Is Regulated by KLF4 and Sp1 and Is Related to Hepatocellular Carcinoma Prognosis. J Biol Chem 2016; 292:2143-2158. [PMID: 28028181 DOI: 10.1074/jbc.m116.770727] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Indexed: 01/01/2023] Open
Abstract
The expression of Ring1- and YY1-binding protein (RYBP) is reduced in several human cancers, but the molecular mechanism(s) have remained elusive. In this study, we used human hepatocellular carcinoma (HCC) cell lines and tissue specimens to study the mechanism and herein report several new findings. First, we cloned and characterized the basal promoter region of the human RYBP gene. We found that the decreased RYBP expression in HCC tissues was not due to promoter sequence variation/polymorphisms or CpG dinucleotide methylation. We identified two transcription factors, KLF4 and Sp1, which directly bind the promoter region of RYBP to induce and suppress RYBP transcription, respectively. We mapped the binding sites of KLF4 and Sp1 on the RYBP promoter. Studies in vitro showed that KLF4 suppresses whereas Sp1 promotes HCC cell growth through modulating RYBP expression. Deregulated KLF4 and Sp1 contributed to decreased expression of RYBP in HCC tumor tissues. Our studies of human HCC tissues indicated that a diminished RYBP level in the tumor (in association with altered KLF4 and Sp1 expression) was statistically associated with a larger tumor size, poorer differentiation, and an increased susceptibility to distant metastasis. These findings help to clarify why RYBP is decreased in HCC and indicate that deregulated KLF4, Sp1, and RYBP may lead to a poorer prognosis. Our findings support the idea that RYBP may represent a target for cancer therapy and suggest that it may be useful as a prognostic biomarker for HCC, either alone or in combination with KLF4 and Sp1.
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Affiliation(s)
- Qiaojiajie Zhao
- From the State Key Laboratory of Medical Molecular Biology, Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, 5 Dong Dan San Tiao, Beijing 100005, China
| | - Weihua Cai
- the Department of Hepatobiliary Surgery, Nantong Third Hospital, Nantong University, Nantong, Jiangsu 226006, China, and
| | - Xuan Zhang
- From the State Key Laboratory of Medical Molecular Biology, Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, 5 Dong Dan San Tiao, Beijing 100005, China
| | - Shuo Tian
- From the State Key Laboratory of Medical Molecular Biology, Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, 5 Dong Dan San Tiao, Beijing 100005, China
| | - Junwen Zhang
- From the State Key Laboratory of Medical Molecular Biology, Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, 5 Dong Dan San Tiao, Beijing 100005, China
| | - Haibo Li
- the Department of Clinical Laboratory Medicine, Nantong Maternal and Child Health Hospital, Nantong, Jiangsu 226018, China
| | - Congcong Hou
- From the State Key Laboratory of Medical Molecular Biology, Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, 5 Dong Dan San Tiao, Beijing 100005, China
| | - Xiaoli Ma
- From the State Key Laboratory of Medical Molecular Biology, Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, 5 Dong Dan San Tiao, Beijing 100005, China
| | - Hong Chen
- From the State Key Laboratory of Medical Molecular Biology, Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, 5 Dong Dan San Tiao, Beijing 100005, China
| | - Bingren Huang
- From the State Key Laboratory of Medical Molecular Biology, Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, 5 Dong Dan San Tiao, Beijing 100005, China,
| | - Deng Chen
- From the State Key Laboratory of Medical Molecular Biology, Department of Biochemistry and Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and School of Basic Medicine, Peking Union Medical College, 5 Dong Dan San Tiao, Beijing 100005, China,
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18
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Differential role of Wnt signaling and base excision repair pathways in gastric adenocarcinoma aggressiveness. Clin Exp Med 2016; 17:505-517. [PMID: 27909884 DOI: 10.1007/s10238-016-0443-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2016] [Accepted: 11/20/2016] [Indexed: 02/06/2023]
Abstract
Aberrant activation of Wnt and base excision repair (BER) signaling pathways are implicated in tumor progression and chemotherapy resistance in gastric adenocarcinoma. This study was conducted to clarify the role of E2F6 and RhoA, components of the Wnt signaling pathway, and SMUG1, a component of the BER pathway in gastric adenocarcinoma. Expression levels and clinicopathological significance of three biomarkers, namely E2F6, RhoA, and SMUG1, as potential signaling molecules involved in tumorigenesis and aggressive behavior, were examined using tissue microarray. Our analysis showed a relative increase in the expression of E2F6 in gastric adenocarcinoma with no lymph node metastasis (χ 2, P = 0.04 and OR, P = 0.08), while overexpression of RhoA and SMUG1 was found more often in the diffuse subtype of gastric adenocarcinoma as compared to the intestinal subtype (χ 2, P = 0.05, OR, P = 0.08 and χ 2, P = 0.001, OR, P = 0.009, respectively). Higher expression of RhoA was frequently seen in tumors with vascular invasion (χ 2, P = 0.01 and OR, P = 0.01). In addition, increased expression of SMUG1 was found more often in poorly differentiated tumors (χ 2, P = 0.01 and OR, P = 0.01). The distinct phenotype of E2F6Low/SMUG1High was more common in poorly differentiated tumors (P = 0.04) and with omental involvement (P = 0.01). The RhoAHigh/SMUG1High expression pattern was significantly more often found in diffuse subtype compared to the intestinal subtype (P = 0.001) as well as in poorly differentiated tumors (P = 0.004). The E2F6Low/SMUG1High and RhoAHigh/SMUG1High phenotypes can be considered as aggressive phenotypes of gastric adenocarcinoma. Our findings also demonstrated the synergistic effect of RhoA and SMUG1 in conferring tumor aggressiveness in diffuse subtype of gastric adenocarcinoma.
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19
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Pei Y, Banerjee S, Sun Z, Jha HC, Saha A, Robertson ES. EBV Nuclear Antigen 3C Mediates Regulation of E2F6 to Inhibit E2F1 Transcription and Promote Cell Proliferation. PLoS Pathog 2016; 12:e1005844. [PMID: 27548379 PMCID: PMC4993364 DOI: 10.1371/journal.ppat.1005844] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 08/05/2016] [Indexed: 12/15/2022] Open
Abstract
Epstein–Barr virus (EBV) is considered a ubiquitous herpesvirus with the ability to cause latent infection in humans worldwide. EBV-association is evidently linked to different types of human malignancies, mainly of epithelial and lymphoid origin. Of interest is the EBV nuclear antigen 3C (EBNA3C) which is critical for EBV-mediated immortalization. Recently, EBNA3C was shown to bind the E2F1 transcription regulator. The E2F transcription factors have crucial roles in various cellular functions, including cell cycle, DNA replication, DNA repair, cell mitosis, and cell fate. Specifically, E2F6, one of the unique E2F family members, is known to be a pRb-independent transcription repressor of E2F-target genes. In our current study, we explore the role of EBNA3C in regulating E2F6 activities. We observed that EBNA3C plays an important role in inducing E2F6 expression in LCLs. Our study also shows that EBNA3C physically interacts with E2F6 at its amino and carboxy terminal domains and they form a protein complex in human cells. In addition, EBNA3C stabilizes the E2F6 protein and is co-localized in the nucleus. We also demonstrated that both EBNA3C and E2F6 contribute to reduction in E2F1 transcriptional activity. Moreover, E2F1 forms a protein complex with EBNA3C and E2F6, and EBNA3C competes with E2F1 for E2F6 binding. E2F6 is also recruited by EBNA3C to the E2F1 promoter, which is critical for EBNA3C-mediated cell proliferation. These results demonstrate a critical role for E2F family members in EBV-induced malignancies, and provide new insights for targeting E2F transcription factors in EBV-associated cancers as potential therapeutic intervention strategies. EBV is associated with a broad range of human cancers. EBV-encoded nuclear antigen 3C (EBNA3C) is one of the essential latent antigens important for deregulating the functions of numerous host transcription factors which play vital roles in B-cell immortalization. The family of E2F transcription factors are involved in diverse cellular functions. More specifically, E2F6 is one of the E2F family members with a unique property of transcriptional repression. Our current study now demonstrates that EBNA3C can enhance E2F6 repressive functions, and is also responsible for increased E2F6 protein expression in EBV-transformed LCLs. EBNA3C directly interacts with E2F6 at its amino and carboxy terminal domains. Additionally, E2F6 was stabilized by EBNA3C and co-localized in nuclear compartments. Our study also demonstrated that EBNA3C and E2F6 expression resulted in decreased transcriptional activity of E2F1, and that EBNA3C, E2F6 and E2F1 can form a protein complex, and EBNA3C competes with E2F1 for E2F6 binding. The recruitment of E2F6 by EBNA3C was also shown to be important for its related cell proliferation. These results showed a crucial role for EBNA3C-mediated deregulation of E2F6 and its impact on the activities of other E2F family members. Our findings also provide new insights for targeting these E2F transcription factors as potential therapeutic intervention strategies in EBV-associated cancers.
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Affiliation(s)
- Yonggang Pei
- Department of Otorhinolaryngology-Head and Neck Surgery, and the Tumor Virology Program, Abramson Comprehensive Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Shuvomoy Banerjee
- Department of Otorhinolaryngology-Head and Neck Surgery, and the Tumor Virology Program, Abramson Comprehensive Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Zhiguo Sun
- Department of Otorhinolaryngology-Head and Neck Surgery, and the Tumor Virology Program, Abramson Comprehensive Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Hem Chandra Jha
- Department of Otorhinolaryngology-Head and Neck Surgery, and the Tumor Virology Program, Abramson Comprehensive Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Abhik Saha
- Department of Biological Sciences, Presidency University, Kolkata, India
| | - Erle S Robertson
- Department of Otorhinolaryngology-Head and Neck Surgery, and the Tumor Virology Program, Abramson Comprehensive Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
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20
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Caffa I, D'Agostino V, Damonte P, Soncini D, Cea M, Monacelli F, Odetti P, Ballestrero A, Provenzani A, Longo VD, Nencioni A. Fasting potentiates the anticancer activity of tyrosine kinase inhibitors by strengthening MAPK signaling inhibition. Oncotarget 2016; 6:11820-32. [PMID: 25909220 PMCID: PMC4494907 DOI: 10.18632/oncotarget.3689] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 03/11/2015] [Indexed: 12/25/2022] Open
Abstract
Tyrosine kinase inhibitors (TKIs) are now the mainstay of treatment in many types of cancer. However, their benefit is frequently short-lived, mandating the search for safe potentiation strategies. Cycles of fasting enhance the activity of chemo-radiotherapy in preclinical cancer models and dietary approaches based on fasting are currently explored in clinical trials. Whether combining fasting with TKIs is going to be potentially beneficial remains unknown. Here we report that starvation conditions increase the ability of commonly administered TKIs, including erlotinib, gefitinib, lapatinib, crizotinib and regorafenib, to block cancer cell growth, to inhibit the mitogen-activated protein kinase (MAPK) signaling pathway and to strengthen E2F-dependent transcription inhibition. In cancer xenografts models, both TKIs and cycles of fasting slowed tumor growth, but, when combined, these interventions were significantly more effective than either type of treatment alone. In conclusion, cycles of fasting or of specifically designed fasting-mimicking diets should be evaluated in clinical studies as a means to potentiate the activity of TKIs in clinical use.
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Affiliation(s)
- Irene Caffa
- Department of Internal Medicine, University of Genoa, Genoa, Italy
| | - Vito D'Agostino
- Laboratory of Genomic Screening, Centre for Integrative Biology, CIBIO, University of Trento, Trento, Italy
| | - Patrizia Damonte
- Department of Internal Medicine, University of Genoa, Genoa, Italy
| | - Debora Soncini
- Department of Internal Medicine, University of Genoa, Genoa, Italy
| | - Michele Cea
- Department of Internal Medicine, University of Genoa, Genoa, Italy
| | | | - Patrizio Odetti
- Department of Internal Medicine, University of Genoa, Genoa, Italy.,IRCCS AOU San Martino-IST, Istituto Nazionale per la Ricerca sul Cancro, Genoa, Italy
| | - Alberto Ballestrero
- Department of Internal Medicine, University of Genoa, Genoa, Italy.,IRCCS AOU San Martino-IST, Istituto Nazionale per la Ricerca sul Cancro, Genoa, Italy
| | - Alessandro Provenzani
- Laboratory of Genomic Screening, Centre for Integrative Biology, CIBIO, University of Trento, Trento, Italy
| | - Valter D Longo
- Longevity Institute, School of Gerontology, Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA.,IFOM, FIRC Institute of Molecular Oncology, Milan, Italy
| | - Alessio Nencioni
- Department of Internal Medicine, University of Genoa, Genoa, Italy.,IRCCS AOU San Martino-IST, Istituto Nazionale per la Ricerca sul Cancro, Genoa, Italy
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21
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Mei S, Zhu H. Multi-label multi-instance transfer learning for simultaneous reconstruction and cross-talk modeling of multiple human signaling pathways. BMC Bioinformatics 2015; 16:417. [PMID: 26718335 PMCID: PMC4697333 DOI: 10.1186/s12859-015-0841-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 07/13/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Signaling pathways play important roles in the life processes of cell growth, cell apoptosis and organism development. At present the signal transduction networks are far from complete. As an effective complement to experimental methods, computational modeling is suited to rapidly reconstruct the signaling pathways at low cost. To our knowledge, the existing computational methods seldom simultaneously exploit more than three signaling pathways into one predictive model for the discovery of novel signaling components and the cross-talk modeling between signaling pathways. RESULTS In this work, we propose a multi-label multi-instance transfer learning method to simultaneously reconstruct 27 human signaling pathways and model their cross-talks. Computational results show that the proposed method demonstrates satisfactory multi-label learning performance and rational proteome-wide predictions. Some predicted signaling components or pathway targeted proteins have been validated by recent literature. The predicted signaling components are further linked to pathways using the experimentally derived PPIs (protein-protein interactions) to reconstruct the human signaling pathways. Thus the map of the cross-talks via common signaling components and common signaling PPIs is conveniently inferred to provide valuable insights into the regulatory and cooperative relationships between signaling pathways. Lastly, gene ontology enrichment analysis is conducted to gain statistical knowledge about the reconstructed human signaling pathways. CONCLUSIONS Multi-label learning framework has been demonstrated effective in this work to model the phenomena that a signaling protein belongs to more than one signaling pathway. As results, novel signaling components and pathways targeted proteins are predicted to simultaneously reconstruct multiple human signaling pathways and the static map of their cross-talks for further biomedical research.
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Affiliation(s)
- Suyu Mei
- Software College, Shenyang Normal University, Shenyang, China. .,Bioinformatics Section, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.
| | - Hao Zhu
- Bioinformatics Section, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China.
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22
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Role of Polycomb RYBP in Maintaining the B-1-to-B-2 B-Cell Lineage Switch in Adult Hematopoiesis. Mol Cell Biol 2015; 36:900-12. [PMID: 26711264 DOI: 10.1128/mcb.00869-15] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 12/18/2015] [Indexed: 01/01/2023] Open
Abstract
Polycomb chromatin modifiers regulate hematopoietic pluripotent stem and progenitor cell self-renewal and expansion. Polycomb complex redundancy and biochemical heterogeneity complicate the unraveling of the functional contributions of distinct components. We have studied the hematopoietic activity of RYBP, a direct interactor and proposed modulator of RING1A/RING1B-dependent histone H2A monoubiquitylation (H2AUb). Using a mouse model to conditionally inactivate Rybp in adult hematopoiesis, we have found that RYBP deletion results in a reversion of B-1-to-B-2 B-cell progenitor ratios, i.e., of the innate (predominantly fetal) to acquired (mostly adult) immunity precursors. Increased numbers of B-1 progenitors correlated with a loss of pre-proB cells, the B-2 progenitors. RYBP-deficient stem and progenitor cell populations (LKS) and isolated common lymphoid progenitors (CLP) gave rise to increased numbers of B-1 progenitors in vitro. Rybp inactivation, however, did not result in changes of global H2AUb and did not interact genetically with Ring1A or Ring1B deletions. These results show that a sustained regulation of the B-1-to-B-2 switch is needed throughout adult life and that RYBP plays an important role in keeping B-2 dominance, most likely independently of its Polycomb affiliation.
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23
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The quest for mammalian Polycomb response elements: are we there yet? Chromosoma 2015; 125:471-96. [PMID: 26453572 PMCID: PMC4901126 DOI: 10.1007/s00412-015-0539-4] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 08/31/2015] [Accepted: 09/02/2015] [Indexed: 12/12/2022]
Abstract
A long-standing mystery in the field of Polycomb and Trithorax regulation is how these proteins, which are highly conserved between flies and mammals, can regulate several hundred equally highly conserved target genes, but recognise these targets via cis-regulatory elements that appear to show no conservation in their DNA sequence. These elements, termed Polycomb/Trithorax response elements (PRE/TREs or PREs), are relatively well characterised in flies, but their mammalian counterparts have proved to be extremely difficult to identify. Recent progress in this endeavour has generated a wealth of data and raised several intriguing questions. Here, we ask why and to what extent mammalian PREs are so different to those of the fly. We review recent advances, evaluate current models and identify open questions in the quest for mammalian PREs.
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Wang W, Cheng J, Qin JJ, Voruganti S, Nag S, Fan J, Gao Q, Zhang R. RYBP expression is associated with better survival of patients with hepatocellular carcinoma (HCC) and responsiveness to chemotherapy of HCC cells in vitro and in vivo. Oncotarget 2015; 5:11604-19. [PMID: 25344099 PMCID: PMC4294343 DOI: 10.18632/oncotarget.2598] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 10/18/2014] [Indexed: 01/17/2023] Open
Abstract
RYBP is a member of the polycomb group (PcG) proteins that typically act as transcriptional repressors via epigenetic modification of chromatin. The present study was designed to investigate the role of RYBP in HCC progression, chemosensitivity, and patient survival, and to explore the underlying molecular mechanism(s). In this study we investigated the expression of RYBP in 400 pairs of human HCC tissues and matched noncancerous samples. The effects of RYBP on HCC tumor growth and metastasis and chemosensitivity were determined both in vitro and in vivo. We herein demonstrate that the RYBP expression in HCC tissue samples was significantly lower than that in matched noncancerous liver tissues. Clinically, the low expression of RYBP was an independent predictor of a poor prognosis in patients with HCC. In in vitro HCC models, enforced RYBP expression inhibited cell growth and invasion, induced apoptosis, and increased the chemosensitivity of the cells, while RYBP knockdown led to the opposite effects. Furthermore, RYBP expression was induced by cisplatin, and adenovirus-mediated RYBP expression inhibited HCC tumor growth and sensitized HCC to conventional chemotherapy in vivo. Our results demonstrate that reactivating RYBP in cancer cells may provide an effective and safe therapeutic approach to HCC therapy.
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Affiliation(s)
- Wei Wang
- Department of Pharmaceutical Sciences, School of pharmacy, Texas Tech University Health Sciences Center, Amarillo, TX, USA. Cancer Biology Center, School of Pharmacy, Texas Tech University Health Sciences Center, Amarillo, TX, USA
| | - Jianwen Cheng
- Liver Cancer Institute, Zhongshan Hospital, and Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Fudan University, Shanghai, China. Institute of Biomedical Sciences, Fudan University, Shanghai, China
| | - Jiang-Jiang Qin
- Department of Pharmaceutical Sciences, School of pharmacy, Texas Tech University Health Sciences Center, Amarillo, TX, USA. Cancer Biology Center, School of Pharmacy, Texas Tech University Health Sciences Center, Amarillo, TX, USA
| | - Sukesh Voruganti
- Department of Pharmaceutical Sciences, School of pharmacy, Texas Tech University Health Sciences Center, Amarillo, TX, USA
| | - Subhasree Nag
- Department of Pharmaceutical Sciences, School of pharmacy, Texas Tech University Health Sciences Center, Amarillo, TX, USA
| | - Jia Fan
- Liver Cancer Institute, Zhongshan Hospital, and Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Fudan University, Shanghai, China. Institute of Biomedical Sciences, Fudan University, Shanghai, China
| | - Qiang Gao
- Liver Cancer Institute, Zhongshan Hospital, and Key Laboratory of Carcinogenesis and Cancer Invasion, Ministry of Education, Fudan University, Shanghai, China. Institute of Biomedical Sciences, Fudan University, Shanghai, China
| | - Ruiwen Zhang
- Department of Pharmaceutical Sciences, School of pharmacy, Texas Tech University Health Sciences Center, Amarillo, TX, USA. Cancer Biology Center, School of Pharmacy, Texas Tech University Health Sciences Center, Amarillo, TX, USA
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25
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Tijchon E, van Ingen Schenau D, van Opzeeland F, Tirone F, Hoogerbrugge PM, Van Leeuwen FN, Scheijen B. Targeted Deletion of Btg1 and Btg2 Results in Homeotic Transformation of the Axial Skeleton. PLoS One 2015. [PMID: 26218146 PMCID: PMC4517811 DOI: 10.1371/journal.pone.0131481] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Btg1 and Btg2 encode highly homologous proteins that are broadly expressed in different cell lineages, and have been implicated in different types of cancer. Btg1 and Btg2 have been shown to modulate the function of different transcriptional regulators, including Hox and Smad transcription factors. In this study, we examined the in vivo role of the mouse Btg1 and Btg2 genes in specifying the regional identity of the axial skeleton. Therefore, we examined the phenotype of Btg1 and Btg2 single knockout mice, as well as novel generated Btg1-/-;Btg2-/- double knockout mice, which were viable, but displayed a non-mendelian inheritance and smaller litter size. We observed both unique and overlapping phenotypes reminiscent of homeotic transformation along the anterior-posterior axis in the single and combined Btg1 and Btg2 knockout animals. Both Btg1-/- and Btg2-/- mice displayed partial posterior transformation of the seventh cervical vertebra, which was more pronounced in Btg1-/-;Btg2-/- mice, demonstrating that Btg1 and Btg2 act in synergy. Loss of Btg2, but not Btg1, was sufficient for complete posterior transformation of the thirteenth thoracic vertebra to the first lumbar vertebra. Moreover, Btg2-/- animals displayed complete posterior transformation of the sixth lumbar vertebra to the first sacral vertebra, which was only partially present at a low frequency in Btg1-/- mice. The Btg1-/-;Btg2-/- animals showed an even stronger phenotype, with L5 to S1 transformation. Together, these data show that both Btg1 and Btg2 are required for normal vertebral patterning of the axial skeleton, but each gene contributes differently in specifying the identity along the anterior-posterior axis of the skeleton.
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Affiliation(s)
- Esther Tijchon
- Laboratory of Pediatric Oncology, Radboud university medical center, Nijmegen, The Netherlands
| | | | - Fred van Opzeeland
- Laboratory of Pediatric Infectious Diseases, Radboud university medical center, Nijmegen, The Netherlands
| | - Felice Tirone
- Institute of Cell Biology and Neurobiology, National Research Council, Fondazione Santa Lucia 00143, Rome, Italy
| | | | - Frank N. Van Leeuwen
- Laboratory of Pediatric Oncology, Radboud university medical center, Nijmegen, The Netherlands
| | - Blanca Scheijen
- Laboratory of Pediatric Oncology, Radboud university medical center, Nijmegen, The Netherlands
- * E-mail:
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26
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Cheng FHC, Aguda BD, Tsai JC, Kochańczyk M, Lin JMJ, Chen GCW, Lai HC, Nephew KP, Hwang TW, Chan MWY. A mathematical model of bimodal epigenetic control of miR-193a in ovarian cancer stem cells. PLoS One 2014; 9:e116050. [PMID: 25545504 PMCID: PMC4278842 DOI: 10.1371/journal.pone.0116050] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 11/30/2014] [Indexed: 12/31/2022] Open
Abstract
Accumulating data indicate that cancer stem cells contribute to tumor chemoresistance and their persistence alters clinical outcome. Our previous study has shown that ovarian cancer may be initiated by ovarian cancer initiating cells (OCIC) characterized by surface antigen CD44 and c-KIT (CD117). It has been experimentally demonstrated that a microRNA, namely miR-193a, targets c-KIT mRNA for degradation and could play a crucial role in ovarian cancer development. How miR-193a is regulated is poorly understood and the emerging picture is complex. To unravel this complexity, we propose a mathematical model to explore how estrogen-mediated up-regulation of another target of miR-193a, namely E2F6, can attenuate the function of miR-193a in two ways, one through a competition of E2F6 and c-KIT transcripts for miR-193a, and second by binding of E2F6 protein, in association with a polycomb complex, to the promoter of miR-193a to down-regulate its transcription. Our model predicts that this bimodal control increases the expression of c-KIT and that the second mode of epigenetic regulation is required to generate a switching behavior in c-KIT and E2F6 expressions. Additional analysis of the TCGA ovarian cancer dataset demonstrates that ovarian cancer patients with low expression of EZH2, a polycomb-group family protein, show positive correlation between E2F6 and c-KIT. We conjecture that a simultaneous EZH2 inhibition and anti-estrogen therapy can constitute an effective combined therapeutic strategy against ovarian cancer.
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Affiliation(s)
- Frank H. C. Cheng
- Department of Life Science, National Chung Cheng University, Min-Hsiung, Chia-Yi, Taiwan, Republic of China
- Institute of Molecular Biology, National Chung Cheng University, Min-Hsiung, Chia-Yi, Taiwan, Republic of China
| | | | - Je-Chiang Tsai
- Department of Mathematics, National Chung Cheng University, Min-Hsiung, Chia-Yi, Taiwan, Republic of China
| | - Marek Kochańczyk
- Institute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland
| | - Jora M. J. Lin
- Department of Life Science, National Chung Cheng University, Min-Hsiung, Chia-Yi, Taiwan, Republic of China
- Institute of Molecular Biology, National Chung Cheng University, Min-Hsiung, Chia-Yi, Taiwan, Republic of China
| | - Gary C. W. Chen
- Department of Life Science, National Chung Cheng University, Min-Hsiung, Chia-Yi, Taiwan, Republic of China
- Institute of Molecular Biology, National Chung Cheng University, Min-Hsiung, Chia-Yi, Taiwan, Republic of China
| | - Hung-Cheng Lai
- Department of Obstetrics and Gynecology, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan, Republic of China
- Department of Obstetrics and Gynecology, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan, Republic of China
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha, People's Republic of China
- Institute of Clinical Pharmacology, Central South University, Changsha, People's Republic of China
- Hunan Key Laboratory of Pharmacogenetics, Changsha, People's Republic of China
| | - Kenneth P. Nephew
- Medical Sciences, Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Bloomington, Indiana, United States of America
| | - Tzy-Wei Hwang
- Department of Mathematics, National Chung Cheng University, Min-Hsiung, Chia-Yi, Taiwan, Republic of China
- * E-mail: (MWYC); (TWH)
| | - Michael W. Y. Chan
- Department of Life Science, National Chung Cheng University, Min-Hsiung, Chia-Yi, Taiwan, Republic of China
- Institute of Molecular Biology, National Chung Cheng University, Min-Hsiung, Chia-Yi, Taiwan, Republic of China
- * E-mail: (MWYC); (TWH)
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27
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Kwak W, Kim JN, Kim D, Hong JS, Jeong JH, Kim H, Cho S, Kim YY. Genome-wide DNA Methylation Profiles of Small Intestine and Liver in Fast-growing and Slow-growing Weaning Piglets. ASIAN-AUSTRALASIAN JOURNAL OF ANIMAL SCIENCES 2014; 27:1532-9. [PMID: 25358311 PMCID: PMC4213696 DOI: 10.5713/ajas.2014.14309] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 06/30/2014] [Accepted: 08/15/2014] [Indexed: 11/27/2022]
Abstract
Although growth rate is one of the main economic traits of concern in pig production, there is limited knowledge on its epigenetic regulation, such as DNA methylation. In this study, we conducted methyl-CpG binding domain protein-enriched genome sequencing (MBD-seq) to compare genome-wide DNA methylation profile of small intestine and liver tissue between fast- and slow-growing weaning piglets. The genome-wide methylation pattern between the two different growing groups showed similar proportion of CpG (regions of DNA where a cytosine nucleotide occurs next to a guanine nucleotide in the linear sequence) coverage, genomic regions, and gene regions. Differentially methylated regions and genes were also identified for downstream analysis. In canonical pathway analysis using differentially methylated genes, pathways (triacylglycerol pathway, some cell cycle related pathways, and insulin receptor signaling pathway) expected to be related to growth rate were enriched in the two organ tissues. Differentially methylated genes were also organized in gene networks related to the cellular development, growth, and carbohydrate metabolism. Even though further study is required, the result of this study may contribute to the understanding of epigenetic regulation in pig growth.
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Affiliation(s)
- Woori Kwak
- C&K Genomics, Seoul 151-919, Korea ; Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul 151-747, Korea
| | | | | | - Jin Su Hong
- Department of Agricultural Biotechnology, Seoul National University, Seoul 151-921, Korea
| | - Jae Hark Jeong
- Department of Agricultural Biotechnology, Seoul National University, Seoul 151-921, Korea
| | - Heebal Kim
- C&K Genomics, Seoul 151-919, Korea ; Interdisciplinary Program in Bioinformatics, Seoul National University, Seoul 151-747, Korea . ; Department of Agricultural Biotechnology, Seoul National University, Seoul 151-921, Korea
| | | | - Yoo Yong Kim
- Department of Agricultural Biotechnology, Seoul National University, Seoul 151-921, Korea
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28
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Inactivation of Rb and E2f8 synergizes to trigger stressed DNA replication during erythroid terminal differentiation. Mol Cell Biol 2014; 34:2833-47. [PMID: 24865965 DOI: 10.1128/mcb.01651-13] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rb is critical for promoting cell cycle exit in cells undergoing terminal differentiation. Here we show that during erythroid terminal differentiation, Rb plays a previously unappreciated and unorthodox role in promoting DNA replication and cell cycle progression. Specifically, inactivation of Rb in erythroid cells led to stressed DNA replication, increased DNA damage, and impaired cell cycle progression, culminating in defective terminal differentiation and anemia. Importantly, all of these defects associated with Rb loss were exacerbated by the concomitant inactivation of E2f8. Gene expression profiling and chromatin immunoprecipitation (ChIP) revealed that Rb and E2F8 cosuppressed a large array of E2F target genes that are critical for DNA replication and cell cycle progression. Remarkably, inactivation of E2f2 rescued the erythropoietic defects resulting from Rb and E2f8 deficiencies. Interestingly, real-time quantitative PCR (qPCR) on E2F2 ChIPs indicated that inactivation of Rb and E2f8 synergizes to increase E2F2 binding to its target gene promoters. Taken together, we propose that Rb and E2F8 collaborate to promote DNA replication and erythroid terminal differentiation by preventing E2F2-mediated aberrant transcriptional activation through the ability of Rb to bind and sequester E2F2 and the ability of E2F8 to compete with E2F2 for E2f-binding sites on target gene promoters.
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29
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Tooze RM. A replicative self-renewal model for long-lived plasma cells: questioning irreversible cell cycle exit. Front Immunol 2013; 4:460. [PMID: 24385976 PMCID: PMC3866514 DOI: 10.3389/fimmu.2013.00460] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 12/02/2013] [Indexed: 12/23/2022] Open
Abstract
Plasma cells are heterogenous in terms of their origins, secretory products, and lifespan. A current paradigm is that cell cycle exit in plasma cell differentiation is irreversible, following a pattern familiar in short-lived effector populations in other hemopoietic lineages. This paradigm no doubt holds true for many plasma cells whose lifespan can be measured in days following the completion of differentiation. Whether this holds true for long-lived bone marrow plasma cells that are potentially maintained for the lifespan of the organism is less apparent. Added to this the mechanisms that establish and maintain cell cycle quiescence in plasma cells are incompletely defined. Gene expression profiling indicates that in the transition of human plasmablasts to long-lived plasma cells a range of cell cycle regulators are induced in a pattern that suggests a quiescence program with potential for cell cycle re-entry. Here a model of relative quiescence with the potential for replicative self-renewal amongst long-lived plasma cells is explored. The implications of such a mechanism would be diverse, and the argument is made here that current evidence is not sufficiently strong that the possibility should be disregarded.
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Affiliation(s)
- Reuben M Tooze
- Section of Experimental Haematology, Leeds Institute of Cancer and Pathology, University of Leeds , Leeds , UK ; Haematological Malignancy Diagnostic Service, Leeds Teaching Hospitals NHS Trust , Leeds , UK
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30
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Leseva M, Santostefano KE, Rosenbluth AL, Hamazaki T, Terada N. E2f6-mediated repression of the meiotic Stag3 and Smc1β genes during early embryonic development requires Ezh2 and not the de novo methyltransferase Dnmt3b. Epigenetics 2013; 8:873-84. [PMID: 23880518 PMCID: PMC3883790 DOI: 10.4161/epi.25522] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 06/12/2013] [Accepted: 06/24/2013] [Indexed: 12/31/2022] Open
Abstract
The E2f6 transcriptional repressor is an E2F-family member essential for the silencing of a group of meiosis-specific genes in somatic tissues. Although E2f6 has been shown to associate with both polycomb repressive complexes (PRC) and the methyltransferase Dnmt3b, the cross-talk between these repressive machineries during E2f6-mediated gene silencing has not been clearly demonstrated yet. In particular, it remains largely undetermined when and how E2f6 establishes repression of meiotic genes during embryonic development. We demonstrate here that the inactivation of a group of E2f6 targeted genes, including Stag3 and Smc1β, first occurs at the transition from mouse embryonic stem cells (ESCs) to epiblast stem cells (EpiSCs), which represent pre- and post-implantation stages, respectively. This process was accompanied by de novo methylation of their promoters. Of interest, despite a clear difference in DNA methylation status, E2f6 was similarly bound to the proximal promoter regions both in ESCs and EpiSCs. Neither E2f6 nor Dnmt3b overexpression in ESCs decreased meiotic gene expression or increased DNA methylation, indicating that additional factors are required for E2f6-mediated repression during the transition. When the SET domain of Ezh2, a core subunit of the PRC2 complex, was deleted, however, repression of Stag3 and Smc1β during embryoid body differentiation was largely impaired, indicating that the event required the enzymatic activity of Ezh2. In addition, repression of Stag3 and Smc1β occurred in the absence of Dnmt3b. The data presented here suggest a primary role of PRC2 in E2f6-mediated gene silencing of the meiotic genes.
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Affiliation(s)
- Milena Leseva
- Department of Pathology; University of Florida College of Medicine; Gainesville, FL USA
| | | | - Amy L Rosenbluth
- Department of Pathology; University of Florida College of Medicine; Gainesville, FL USA
| | - Takashi Hamazaki
- Department of Pathology; University of Florida College of Medicine; Gainesville, FL USA
- Department of Pediatrics; Osaka City University Graduate School of Medicine; Osaka, Japan
| | - Naohiro Terada
- Department of Pathology; University of Florida College of Medicine; Gainesville, FL USA
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Biochemical and functional interactions of human papillomavirus proteins with polycomb group proteins. Viruses 2013; 5:1231-49. [PMID: 23673719 PMCID: PMC3712305 DOI: 10.3390/v5051231] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 04/23/2013] [Accepted: 04/27/2013] [Indexed: 12/22/2022] Open
Abstract
The role of enzymes involved in polycomb repression of gene transcription has been studied extensively in human cancer. Polycomb repressive complexes mediate oncogene-induced senescence, a principal innate cell-intrinsic tumor suppressor pathway that thwarts expansion of cells that have suffered oncogenic hits. Infections with human cancer viruses including human papillomaviruses (HPVs) and Epstein-Barr virus can trigger oncogene-induced senescence, and the viruses have evolved strategies to abrogate this response in order to establish an infection and reprogram their host cells to establish a long-term persistent infection. As a consequence of inhibiting polycomb repression and evading oncogene induced-senescence, HPV infected cells have an altered epigenetic program as evidenced by aberrant homeobox gene expression. Similar alterations are frequently observed in non-virus associated human cancers and may be harnessed for diagnosis and therapy.
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In vivo regulation of E2F1 by Polycomb group genes in Drosophila. G3-GENES GENOMES GENETICS 2012; 2:1651-60. [PMID: 23275887 PMCID: PMC3516486 DOI: 10.1534/g3.112.004333] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Accepted: 10/24/2012] [Indexed: 01/17/2023]
Abstract
The E2F transcription factors are important regulators of the cell cycle whose function is commonly misregulated in cancer. To identify novel regulators of E2F1 activity in vivo, we used Drosophila to conduct genetic screens. For this, we generated transgenic lines that allow the tissue-specific depletion of dE2F1 by RNAi. Expression of these transgenes using Gal4 drivers in the eyes and wings generated reliable and modifiable phenotypes. We then conducted genetic screens testing the capacity of Exelixis deficiencies to modify these E2F1-RNAi phenotypes. From these screens, we identified mutant alleles of Suppressor of zeste 2 [Su(z)2] and multiple Polycomb group genes as strong suppressors of the E2F1-RNA interference phenotypes. In validation of our genetic data, we find that depleting Su(z)2 in cultured Drosophila cells restores the cell-proliferation defects caused by reduction of dE2F1 by elevating the level of dE2f1. Furthermore, analyses of methylation status of histone H3 lysine 27 (H3K27me) from the published modENCODE data sets suggest that the genomic regions harboring dE2f1 gene and certain dE2f1 target genes display H3K27me during development and in several Drosophila cell lines. These in vivo observations suggest that the Polycomb group may regulate cell proliferation by repressing the transcription of dE2f1 and certain dE2F1 target genes. This mechanism may play an important role in coordinating cellular differentiation and proliferation during Drosophila development.
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Leung JY, Nevins JR. E2F6 associates with BRG1 in transcriptional regulation. PLoS One 2012; 7:e47967. [PMID: 23082233 PMCID: PMC3474740 DOI: 10.1371/journal.pone.0047967] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2012] [Accepted: 09/19/2012] [Indexed: 11/23/2022] Open
Abstract
The E2F6 protein functions as an Rb-independent repressor of gene transcription. We have previously provided evidence suggesting a role for E2F6 in repression of E2F-responsive genes at S phase. Here, we have identified BRG1, the ATPase subunit of the SWI/SNF chromatin-remodeling complex, as an E2F6 interacting protein. Immunoprecipitation experiments demonstrate that BRG1 binds specifically to E2F6 and E2F4 but not the activator E2Fs. E2F6 was also able to interact with BAF155, a BRG1-associated factor, in the SWI/SNF complex. Chromatin immunoprecipitation assays demonstrate the binding of BRG1 coincident with E2F6 on G1/S gene promoters during S phase. Collectively, our studies suggest that E2F6 may recruit BRG1 in transcriptional regulation of genes important for G1/S phase transition of the cell cycle.
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Affiliation(s)
- Janet Y. Leung
- Duke Institute for Genome Sciences and Policy, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Joseph R. Nevins
- Duke Institute for Genome Sciences and Policy, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
- * E-mail:
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Aksoy O, Chicas A, Zeng T, Zhao Z, McCurrach M, Wang X, Lowe SW. The atypical E2F family member E2F7 couples the p53 and RB pathways during cellular senescence. Genes Dev 2012; 26:1546-57. [PMID: 22802529 DOI: 10.1101/gad.196238.112] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Oncogene-induced senescence is an anti-proliferative stress response program that acts as a fail-safe mechanism to limit oncogenic transformation and is regulated by the retinoblastoma protein (RB) and p53 tumor suppressor pathways. We identify the atypical E2F family member E2F7 as the only E2F transcription factor potently up-regulated during oncogene-induced senescence, a setting where it acts in response to p53 as a direct transcriptional target. Once induced, E2F7 binds and represses a series of E2F target genes and cooperates with RB to efficiently promote cell cycle arrest and limit oncogenic transformation. Disruption of RB triggers a further increase in E2F7, which induces a second cell cycle checkpoint that prevents unconstrained cell division despite aberrant DNA replication. Mechanistically, E2F7 compensates for the loss of RB in repressing mitotic E2F target genes. Together, our results identify a causal role for E2F7 in cellular senescence and uncover a novel link between the RB and p53 pathways.
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Affiliation(s)
- Ozlem Aksoy
- Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA
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35
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Zou L, Xu HG, Ren W, Jin R, Wang Y, Zhou GP. Transcriptional activation of the human CD2AP promoter by E2F1. PLoS One 2012; 7:e42774. [PMID: 22880102 PMCID: PMC3411847 DOI: 10.1371/journal.pone.0042774] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 07/11/2012] [Indexed: 12/24/2022] Open
Abstract
CD2-associated protein (CD2AP) is an adaptor molecule involved in T cell receptor signaling and podocyte homeostasis. CD2AP-deficient mice develop nephritic syndrome and renal failure caused by glomerulosclerosis. Transcription factor E2F1 is a key regulator of cell proliferation and apoptosis. Here we report that E2F1 up-regulates the human CD2AP promoter and further increases the mRNA and protein levels of the human CD2AP in human embryonic kidney (HEK) 293 cells. By semi-quantitative RT-PCR and Western blot analysis we demonstrate that ectopic expression of E2F1 elevates the mRNA and protein levels of CD2AP. Consistently, transient transfection assays prove that overexpression of E2F1 transactivates the CD2AP promoter while knocking-down of endogenous E2F1 by a shRNA strategy results in reduction of the CD2AP promoter activity. Toward understanding the underlying mechanism of this regulation, we performed chromatin immunoprecipitation and mutations of the putative Sp1 binding sites, demonstrating that E2F1 can bind to Sp1 binding site and overexpression of E2F1 is capable of increasing the binding of E2F1 and decreasing the binding of Sp1 to Sp1 binding sites.
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Affiliation(s)
- Li Zou
- Department of Pediatrics, The First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Hua-Guo Xu
- Department of Pediatrics, The First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, China
- Department of Clinical Laboratory, The First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Wei Ren
- Department of Pediatrics, The First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Rui Jin
- Department of Pediatrics, The First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Yi Wang
- Department of Pediatrics, The First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Guo-Ping Zhou
- Department of Pediatrics, The First Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu Province, China
- * E-mail:
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Cao L, Bombard J, Cintron K, Sheedy J, Weetall ML, Davis TW. BMI1 as a novel target for drug discovery in cancer. J Cell Biochem 2012; 112:2729-41. [PMID: 21678481 DOI: 10.1002/jcb.23234] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Growing evidence has demonstrated that clonogenic cancer stem (initiating) cells are responsible for tumor regrowth and disease relapse. Bmi-1 plays a critical role in the self-renewal of adult stem cells. The Bmi-1 protein is elevated in many types of cancers, and experimental reduction of Bmi-1 protein levels by small interfering RNA (siRNA) causes apoptosis and/or senescence in tumor cells in vitro and increases susceptibility to cytotoxic agents. The Bmi-1 protein has no known enzymatic activity, but serves as the key regulatory component of the PRC1 complex (polycomb repressive complex-1). This complex influences chromatin structure and regulates transcriptional activity of a number of important loci including the Ink4a locus which encodes the tumor suppressor proteins p16(Ink4a) and p14(Arf) . In this prospective study, we will discuss the implication of BMI1 in cancers, the biology of BMI1, and the regulatory control of BMI1 expression. The target validation and the future prospects of targeting BMI1 in cancer therapy are also discussed.
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Affiliation(s)
- Liangxian Cao
- PTC Therapeutics, Inc., South Plainfield, New Jersey, New Jersey 07080, USA.
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RXRα deletion and E6E7 oncogene expression are sufficient to induce cervical malignant lesions in vivo. Cancer Lett 2012; 317:226-36. [DOI: 10.1016/j.canlet.2011.11.031] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Revised: 11/23/2011] [Accepted: 11/23/2011] [Indexed: 01/01/2023]
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Concomitant inactivation of Rb and E2f8 in hematopoietic stem cells synergizes to induce severe anemia. Blood 2012; 119:4532-42. [PMID: 22422820 DOI: 10.1182/blood-2011-10-388231] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The retinoblastoma (Rb) tumor suppressor plays important roles in regulating hematopoiesis, particularly erythropoiesis. In an effort to understand whether Rb function can be mediated by E2F transcription factors in a BM-derived hematopoietic system in mice, we uncovered a functional synergy between Rb and E2F8 to promote erythropoiesis and to prevent anemia. Specifically, whereas Mx1-Cre-mediated inactivation of Rb or E2f8 in hematopoietic stem cells only led to mild erythropoietic defects, concomitant inactivation of both genes resulted in marked ineffective erythropoiesis and mild hemolysis, leading to severe anemia despite the presence of enhanced extramedullary erythropoiesis. Interestingly, although ineffective erythropoiesis was already present in the RbΔ/Δ mice and exacerbated in the RbΔ/Δ;E2f8Δ/Δ mice, hemolysis was exclusively manifested in the double-knockout mice. Using an adoptive transfer system and an erythroid-specific knockout system, we have shown that the synergy of Rb and E2f8 deficiency in triggering severe anemia is intrinsic to the erythroid lineage. Surprisingly, concomitant inactivation of Rb and E2f7, a close family member of E2f8, did not substantially worsen the erythropoietic defect resulted from Rb deficiency. The results of the present study reveal the specificity of E2F8 in mediating Rb function in erythropoiesis and suggest critical and overlapping roles of Rb and E2f8 in maintaining normal erythropoiesis and in preventing hemolysis.
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Dietrich N, Lerdrup M, Landt E, Agrawal-Singh S, Bak M, Tommerup N, Rappsilber J, Södersten E, Hansen K. REST-mediated recruitment of polycomb repressor complexes in mammalian cells. PLoS Genet 2012; 8:e1002494. [PMID: 22396653 PMCID: PMC3291536 DOI: 10.1371/journal.pgen.1002494] [Citation(s) in RCA: 123] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Accepted: 12/07/2011] [Indexed: 12/02/2022] Open
Abstract
Polycomb Repressive Complex (PRC) 1 and PRC2 regulate genes involved in differentiation and development. However, the mechanism for how PRC1 and PRC2 are recruited to genes in mammalian cells is unclear. Here we present evidence for an interaction between the transcription factor REST, PRC1, and PRC2 and show that RNF2 and REST co-regulate a number of neuronal genes in human teratocarcinoma cells (NT2-D1). Using NT2-D1 cells as a model of neuronal differentiation, we furthermore showed that retinoic-acid stimulation led to displacement of PRC1 at REST binding sites, reduced H3K27Me3, and increased gene expression. Genome-wide analysis of Polycomb binding in Rest−/− and Eed−/− mouse embryonic stem (mES) cells showed that Rest was required for PRC1 recruitment to a subset of Polycomb regulated neuronal genes. Furthermore, we found that PRC1 can be recruited to Rest binding sites independently of CpG islands and the H3K27Me3 mark. Surprisingly, PRC2 was frequently increased around Rest binding sites located in CpG-rich regions in the Rest−/− mES cells, indicating a more complex interplay where Rest also can limit PRC2 recruitment. Therefore, we propose that Rest has context-dependent functions for PRC1- and PRC2- recruitment, which allows this transcription factor to act both as a recruiter of Polycomb as well as a limiting factor for PRC2 recruitment at CpG islands. Multicellular organisms are composed of a large number of specialized cell types that all originate from the Embryonic Stem cell (ES cell). It is crucial for the maintenance of naïve ES cells that developmental genes are kept in an off-state until appropriate differentiation stimuli are received. Polycomb Repressive Complexes, PRC1 and PRC2, are bound at and repress the activity of a large number of key developmental genes in ES cells and at different stages of differentiation. While in Drosophila the PRC complexes are recruited to DNA elements called Polycomb Response Elements (PREs), through the interaction with transcription factors; examples of such factors remain poorly characterized in mammals. We here demonstrate that the transcription factor Rest interacts with and is required for recruitment of PRC1 and PRC2 to a subset of Rest target genes in mouse embryonic stem (mES) cells. In line with REST being a repressor of neuronal genes, we found that PRC1 and PRC2 co-localized with REST at genes involved in neuronal development and got displaced during neuronal differentiation. Based on our data we propose that the PRC1 and PRC2 complexes function as co-repressors for Rest to control the timed expression of developmental genes in the process of cellular differentiation.
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Affiliation(s)
- Nikolaj Dietrich
- Biotech Research and Innovation Centre (BRIC) and Centre for Epigenetics, University of Copenhagen, Copenhagen, Denmark
| | - Mads Lerdrup
- Biotech Research and Innovation Centre (BRIC) and Centre for Epigenetics, University of Copenhagen, Copenhagen, Denmark
| | - Eskild Landt
- Biotech Research and Innovation Centre (BRIC) and Centre for Epigenetics, University of Copenhagen, Copenhagen, Denmark
| | - Shuchi Agrawal-Singh
- Biotech Research and Innovation Centre (BRIC) and Centre for Epigenetics, University of Copenhagen, Copenhagen, Denmark
| | - Mads Bak
- Wilhelm Johannsen Centre For Functional Genome Research, Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Niels Tommerup
- Wilhelm Johannsen Centre For Functional Genome Research, Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Juri Rappsilber
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Erik Södersten
- Biotech Research and Innovation Centre (BRIC) and Centre for Epigenetics, University of Copenhagen, Copenhagen, Denmark
| | - Klaus Hansen
- Biotech Research and Innovation Centre (BRIC) and Centre for Epigenetics, University of Copenhagen, Copenhagen, Denmark
- * E-mail:
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Tavares L, Dimitrova E, Oxley D, Webster J, Poot R, Demmers J, Bezstarosti K, Taylor S, Ura H, Koide H, Wutz A, Vidal M, Elderkin S, Brockdorff N. RYBP-PRC1 complexes mediate H2A ubiquitylation at polycomb target sites independently of PRC2 and H3K27me3. Cell 2012; 148:664-78. [PMID: 22325148 PMCID: PMC3281992 DOI: 10.1016/j.cell.2011.12.029] [Citation(s) in RCA: 426] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Revised: 10/19/2011] [Accepted: 12/15/2011] [Indexed: 12/20/2022]
Abstract
Polycomb-repressive complex 1 (PRC1) has a central role in the regulation of heritable gene silencing during differentiation and development. PRC1 recruitment is generally attributed to interaction of the chromodomain of the core protein Polycomb with trimethyl histone H3K27 (H3K27me3), catalyzed by a second complex, PRC2. Unexpectedly we find that RING1B, the catalytic subunit of PRC1, and associated monoubiquitylation of histone H2A are targeted to closely overlapping sites in wild-type and PRC2-deficient mouse embryonic stem cells (mESCs), demonstrating an H3K27me3-independent pathway for recruitment of PRC1 activity. We show that this pathway is mediated by RYBP-PRC1, a complex comprising catalytic subunits of PRC1 and the protein RYBP. RYBP-PRC1 is recruited to target loci in mESCs and is also involved in Xist RNA-mediated silencing, the latter suggesting a wider role in Polycomb silencing. We discuss the implications of these findings for understanding recruitment and function of Polycomb repressors.
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Affiliation(s)
- Lígia Tavares
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Emilia Dimitrova
- Nuclear Dynamics, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - David Oxley
- Mass Spectrometry, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Judith Webster
- Mass Spectrometry, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Raymond Poot
- Department of Cell Biology, Erasmus Medical Center, Dr. Molewaterplein 50, 3015GE Rotterdam, The Netherlands
| | - Jeroen Demmers
- Proteomics Center, Erasmus Medical Center, Dr. Molewaterplein 50, 3015GE Rotterdam, The Netherlands
| | - Karel Bezstarosti
- Proteomics Center, Erasmus Medical Center, Dr. Molewaterplein 50, 3015GE Rotterdam, The Netherlands
| | - Stephen Taylor
- Computational Biology Research Group, WIMM, University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DS, UK
| | - Hiroki Ura
- Department of Stem Cell Biology, Graduate School of Medical Science, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa 920-8640, Japan
| | - Hiroshi Koide
- Department of Stem Cell Biology, Graduate School of Medical Science, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa 920-8640, Japan
| | - Anton Wutz
- Wellcome Trust Centre for Stem Cell Research, Tennis Court Road, Cambridge CB2 1QR, UK
| | - Miguel Vidal
- Cell Proliferation and Development, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Cientificas (CSIC), 28040 Madrid, Spain
| | - Sarah Elderkin
- Nuclear Dynamics, Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Neil Brockdorff
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
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41
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RYBP represses endogenous retroviruses and preimplantation- and germ line-specific genes in mouse embryonic stem cells. Mol Cell Biol 2012; 32:1139-49. [PMID: 22269950 DOI: 10.1128/mcb.06441-11] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Polycomb repressive complexes (PRCs) are important chromatin regulators of embryonic stem (ES) cell function. RYBP binds Polycomb H2A monoubiquitin ligases Ring1A and Ring1B and has been suggested to assist PRC localization to their targets. Moreover, constitutive inactivation of RYBP precludes ES cell formation. Using ES cells conditionally deficient in RYBP, we found that RYBP is not required for maintenance of the ES cell state, although mutant cells differentiate abnormally. Genome-wide chromatin association studies showed RYBP binding to promoters of Polycomb targets, although its presence is dispensable for gene repression. We discovered, using Eed-knockout (KO) ES cells, that RYBP binding to promoters was independent of H3K27me3. However, recruiting of PRC1 subunits Ring1B and Mel18 to their targets was not altered in the absence of RYBP. In contrast, we have found that RYBP efficiently represses endogenous retroviruses (murine endogenous retrovirus [MuERV] class) and preimplantation (including zygotic genome activation stage)- and germ line-specific genes. These observations support a selective repressor activity for RYBP that is dispensable for Polycomb function in the ES cell state. Also, they suggest a role for RYBP in epigenetic resetting during preimplantation development through repression of germ line genes and PcG targets before formation of pluripotent epiblast cells.
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42
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Abstract
The last decade has seen an incredible breakthrough in technologies that allow histones, transcription factors (TFs), and RNA polymerases to be precisely mapped throughout the genome. From this research, it is clear that there is a complex interaction between the chromatin landscape and the general transcriptional machinery and that the dynamic control of this interface is central to gene regulation. However, the chromatin remodeling enzymes and general TFs cannot, on their own, recognize and stably bind to promoter or enhancer regions. Rather, they are recruited to cis regulatory regions through interaction with site-specific DNA binding TFs and/or proteins that recognize epigenetic marks such as methylated cytosines or specifically modified amino acids in histones. These "recruitment" factors are modular in structure, reflecting their ability to interact with the genome via one region of the protein and to simultaneously bind to other regulatory proteins via "effector" domains. In this chapter, we provide examples of common effector domains that can function in transcriptional regulation via their ability to (a) interact with the basal transcriptional machinery and general co-activators, (b) interact with other TFs to allow cooperative binding, and (c) directly or indirectly recruit histone and chromatin modifying enzymes.
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Affiliation(s)
- Seth Frietze
- Department of Biochemistry and Molecular Biology, University of Southern California, Los Angeles, CA, 90033, USA,
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43
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Wang R, Taylor AB, Leal BZ, Chadwell LV, Ilangovan U, Robinson AK, Schirf V, Hart PJ, Lafer EM, Demeler B, Hinck AP, McEwen DG, Kim CA. Polycomb group targeting through different binding partners of RING1B C-terminal domain. Structure 2010; 18:966-75. [PMID: 20696397 DOI: 10.1016/j.str.2010.04.013] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Revised: 04/21/2010] [Accepted: 04/25/2010] [Indexed: 12/31/2022]
Abstract
RING1B, a Polycomb Group (PcG) protein, binds methylated chromatin through its association with another PcG protein called Polycomb (Pc). However, RING1B can associate with nonmethylated chromatin suggesting an alternate mechanism for RING1B interaction with chromatin. Here, we demonstrate that two proteins with little sequence identity between them, the Pc cbox domain and RYBP, bind the same surface on the C-terminal domain of RING1B (C-RING1B). Pc cbox and RYBP each fold into a nearly identical, intermolecular beta sheet with C-RING1B and a loop structure which are completely different in the two proteins. Both the beta sheet and loop are required for stable binding and transcription repression. Further, a mutation engineered to disrupt binding on the Drosophila dRING1 protein prevents chromatin association and PcG function in vivo. These results suggest that PcG targeting to different chromatin locations relies, in part, on binding partners of C-RING1B that are diverse in sequence and structure.
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Affiliation(s)
- Renjing Wang
- Department of Biochemistry, University of Texas Health Science Center at San Antonio, MSC 7760, 7703 Floyd Curl Drive, San Antonio, TX 78229-3990, USA
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Wirt SE, Adler AS, Gebala V, Weimann JM, Schaffer BE, Saddic LA, Viatour P, Vogel H, Chang HY, Meissner A, Sage J. G1 arrest and differentiation can occur independently of Rb family function. ACTA ACUST UNITED AC 2010; 191:809-25. [PMID: 21059851 PMCID: PMC2983066 DOI: 10.1083/jcb.201003048] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Repression of E2F target genes is required for cell cycle arrest in Rb family (Rb, p107, and p130)-deficient cells. The ability of progenitor cells to exit the cell cycle is essential for proper embryonic development and homeostasis, but the mechanisms governing cell cycle exit are still not fully understood. Here, we tested the requirement for the retinoblastoma (Rb) protein and its family members p107 and p130 in G0/G1 arrest and differentiation in mammalian cells. We found that Rb family triple knockout (TKO) mouse embryos survive until days 9–11 of gestation. Strikingly, some TKO cells, including in epithelial and neural lineages, are able to exit the cell cycle in G0/G1 and differentiate in teratomas and in culture. This ability of TKO cells to arrest in G0/G1 is associated with the repression of key E2F target genes. Thus, G1 arrest is not always dependent on Rb family members, which illustrates the robustness of cell cycle regulatory networks during differentiation and allows for the identification of candidate pathways to inhibit the expansion of cancer cells with mutations in the Rb pathway.
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Affiliation(s)
- Stacey E Wirt
- Department of Pediatrics, Stanford Medical School, Stanford, CA 94305, USA
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45
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Swiss VA, Casaccia P. Cell-context specific role of the E2F/Rb pathway in development and disease. Glia 2010; 58:377-90. [PMID: 19795505 DOI: 10.1002/glia.20933] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Development of the central nervous system (CNS) requires the generation of neuronal and glial cell subtypes in appropriate numbers, and this demands the careful coordination of cell-cycle exit, survival, and differentiation. The E2F/Rb pathway is critical for cell-cycle regulation and also modulates survival and differentiation of distinct cell types in the developing and adult CNS. In this review, we first present the specific temporal patterns of expression of the E2F and Rb family members during CNS development and then discuss the genetic ablation of single or multiple members of these two families. Overall, the available data suggest a time-dependent and cell-context specific role of E2F and Rb family members in the developing and adult CNS.
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Affiliation(s)
- Victoria A Swiss
- Department of Neuroscience and Genetics and Genomics, Mount Sinai School of Medicine, New York, New York 10029, USA
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46
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Beck S, Faradji F, Brock H, Peronnet F. Maintenance of Hox Gene Expression Patterns. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 689:41-62. [DOI: 10.1007/978-1-4419-6673-5_3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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47
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Abstract
Mutations of the retinoblastoma tumour suppressor gene (RB1) or components regulating the RB pathway have been identified in almost every human malignancy. The E2F transcription factors function in cell cycle control and are intimately regulated by RB. Studies of model organisms have revealed conserved functions for E2Fs during development, suggesting that the cancer-related proliferative roles of E2F family members represent a recent evolutionary adaptation. However, given that some human tumours have concurrent RB1 inactivation and E2F amplification and overexpression, we propose that there are alternative tumour-promoting activities for the E2F family, which are independent of cell cycle regulation.
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Affiliation(s)
- Hui-Zi Chen
- Human Cancer Genetics Program, Department of Molecular Virology, Immunology and Medical Genetics and Department of Molecular Genetics, The Ohio State University, Columbus, Ohio 43210, USA
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48
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Abstract
The Polycomb group (PcG) proteins are transcriptional repressors that regulate lineage choices during development and differentiation. Recent studies have advanced our understanding of how the PcG proteins regulate cell fate decisions and how their deregulation potentially contributes to cancer. In this Review we discuss the emerging roles of long non-coding RNAs (ncRNAs) and a subset of transcription factors, which we call cell fate transcription factors, in the regulation of PcG association with target genes. We also speculate about how their deregulation contributes to tumorigenesis.
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Affiliation(s)
- Adrian P Bracken
- The Smurfit Institute of Genetics, Trinity College Dublin and The Adelaide & Meath Hospital, including the National Children's Hospital, Dublin, Ireland.
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49
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Niessen HEC, Demmers JA, Voncken JW. Talking to chromatin: post-translational modulation of polycomb group function. Epigenetics Chromatin 2009; 2:10. [PMID: 19723311 PMCID: PMC2745409 DOI: 10.1186/1756-8935-2-10] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Accepted: 09/01/2009] [Indexed: 11/26/2022] Open
Abstract
Polycomb Group proteins are important epigenetic regulators of gene expression. Epigenetic control by polycomb Group proteins involves intrinsic as well as associated enzymatic activities. Polycomb target genes change with cellular context, lineage commitment and differentiation status, revealing dynamic regulation of polycomb function. It is currently unclear how this dynamic modulation is controlled and how signaling affects polycomb-mediated epigenetic processes at the molecular level. Experimental evidence on regulation of polycomb function by post-translational mechanisms is steadily emerging: Polycomb Group proteins are targeted for ubiquitylation, sumoylation and phosphorylation. In addition, specific Polycomb Group proteins modify other (chromatin) associated proteins via similar post-translational modifications. Such modifications affect protein function by affecting protein stability, protein-protein interactions and enzymatic activities. Here, we review current insights in covalent modification of Polycomb Group proteins in the context of protein function and present a tentative view of integrated signaling to chromatin in the context of phosphorylation. Clearly, the available literature reveals just the tip of the iceberg, and exact molecular mechanisms in, and the biological relevance of post-translational regulation of polycomb function await further elucidation. Our understanding of causes and consequences of post-translational modification of polycomb proteins will gain significantly from in vivo validation experiments. Impaired polycomb function has important repercussions for stem cell function, development and disease. Ultimately, increased understanding of signaling to chromatin and the mechanisms involved in epigenetic remodeling will contribute to the development of therapeutic interventions in cell fate decisions in development and disease.
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Affiliation(s)
- Hanneke E C Niessen
- Molecular Genetics, GROW School for Oncology and Developmental Biology, Maastricht University, Maastricht, The Netherlands.
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Expression of E2F transcription factor family genes during chick wing development. Gene Expr Patterns 2009; 9:528-31. [PMID: 19595792 DOI: 10.1016/j.gep.2009.07.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Revised: 06/30/2009] [Accepted: 07/02/2009] [Indexed: 11/23/2022]
Abstract
The E2F family of transcriptional regulators activate or repress gene expression during specific phases of the cell cycle and control various processes including proliferation, apoptosis and differentiation. However, little is known about the developmental roles of E2F transcription factors in higher vertebrates. The chick wing is an excellent system for studying these processes because, in addition to having a rich classical embryology, it is increasingly amenable to molecular and genomic approaches. We show that the human and mouse complement of eight E2F transcription factors is conserved in the chicken and that chicken E2F genes are expressed in different spatial and temporal patterns during wing development. We discuss how the expression patterns of the eight chicken E2F transcription factors might be related to important morphogenetic events.
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