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Ng LY, Ma HT, Poon RYC. Cyclin A-CDK1 suppresses the expression of the CDK1 activator CDC25A to safeguard timely mitotic entry. J Biol Chem 2023; 299:102957. [PMID: 36717077 PMCID: PMC9986519 DOI: 10.1016/j.jbc.2023.102957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 01/19/2023] [Accepted: 01/20/2023] [Indexed: 01/29/2023] Open
Abstract
Cyclin A and CDC25A are both activators of cyclin-dependent kinases (CDKs): cyclin A acts as an activating subunit of CDKs and CDC25A a phosphatase of the inhibitory phosphorylation sites of the CDKs. In this study, we uncovered an inverse relationship between the two CDK activators. As cyclin A is an essential gene, we generated a conditional silencing cell line using a combination of CRISPR-Cas9 and degron-tagged cyclin A. Destruction of cyclin A promoted an acute accumulation of CDC25A. The increase of CDC25A after cyclin A depletion occurred throughout the cell cycle and was independent on cell cycle delay caused by cyclin A deficiency. Moreover, we determined that the inverse relationship with cyclin A was specific for CDC25A and not for other CDC25 family members or kinases that regulate the same sites in CDKs. Unexpectedly, the upregulation of CDC25A was mainly caused by an increase in transcriptional activity instead of a change in the stability of the protein. Reversing the accumulation of CDC25A severely delayed G2-M in cyclin A-depleted cells. Taken together, these data provide evidence of a compensatory mechanism involving CDC25A that ensures timely mitotic entry at different levels of cyclin A.
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Affiliation(s)
- Lau Yan Ng
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Hoi Tang Ma
- Department of Pathology, The University of Hong Kong, Hong Kong, China; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong, China
| | - Randy Y C Poon
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong, China; State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Hong Kong, China.
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2
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Deregulated estrogen receptor signaling and DNA damage response in breast tumorigenesis. Biochim Biophys Acta Rev Cancer 2020; 1875:188482. [PMID: 33260050 DOI: 10.1016/j.bbcan.2020.188482] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 11/05/2020] [Accepted: 11/12/2020] [Indexed: 02/07/2023]
Abstract
Carriers of BRCA1 mutations have a higher chance of developing cancers in hormone-responsive tissues like the breast, ovary and prostate, compared to other tissues. These tumors generally exhibit basal-like characters and do not express estrogen receptor (ER) or progesterone receptor (PR). Intriguingly, BRCA1 mutated breast cancers have a less favorable clinical outcome, as they will not respond to hormone therapy. BRCA1 has been reported to exhibit ligand dependent and independent transcriptional inhibition of ER-α; however, there exists a controversy on whether BRCA1 induces or inhibits ER-α expression. The mechanisms associated with resistance of BRCA1 mutated cancers to hormone therapy, as well as the tissue restriction exhibited by BRCA1 mutated tumors are still largely unknown. BRCA1 mutated tumors possess increased DNA damages and decreased genomic integrity, as BRCA1 plays a cardinal role in high fidelity DNA damage repair pathways, like homologous recombination (HR). The existence of cross regulatory signaling networks between ER-α and BRCA1 speculates a role of ER on BRCA1 dependent DDR pathways. Thus, the loss or haploinsufficiency of BRCA1 and the consequential deregulation of ER-α signaling may result in persistence of unrepaired DNA damages, eventually leading to tumorigenesis. Therefore, understanding of this cross-talk between ER-α and BRCA1, with regard to DDR, will provide critical insights to steer drug development and therapy for breast/ovarian cancers. This review discusses the mechanisms by which estrogen and ER signaling influence BRCA1 mediated DNA damage response and repair pathways in the mammalian system.
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3
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Sheldon LA. Inhibition of E2F1 activity and cell cycle progression by arsenic via retinoblastoma protein. Cell Cycle 2017; 16:2058-2072. [PMID: 28880708 DOI: 10.1080/15384101.2017.1338221] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The regulation of cell cycle progression by steroid hormones and growth factors is important for maintaining normal cellular processes including development and cell proliferation. Deregulated progression through the G1/S and G2/M cell cycle transitions can lead to uncontrolled cell proliferation and cancer. The transcription factor E2F1, a key cell cycle regulator, targets genes encoding proteins that regulate cell cycle progression through the G1/S transition as well as proteins important in DNA repair and apoptosis. E2F1 expression and activity is inhibited by inorganic arsenic (iAs) that has a dual role as a cancer therapeutic and as a toxin that leads to diseases including cancer. An understanding of what underlies this dichotomy will contribute to understanding how to use iAs as a more effective therapeutic and also how to treat cancers that iAs promotes. Here, we show that quiescent breast adenocarcinoma MCF-7 cells treated with 17-β estradiol (E2) progress through the cell cycle, but few cells treated with E2 + iAs progress from G1 into S-phase due to a block in cell cycle progression. Our data support a model in which iAs inhibits the dissociation of E2F1 from the tumor suppressor, retinoblastoma protein (pRB) due to changes in pRB phosphorylation which leads to decreased E2F1 transcriptional activity. These findings present an explanation for how iAs can disrupt cell cycle progression through E2F1-pRB and has implications for how iAs acts as a cancer therapeutic as well as how it may promote tumorigenesis through decreased DNA repair.
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Affiliation(s)
- Lynn A Sheldon
- a Geisel School of Medicine at Dartmouth, Department of Molecular and Systems Biology , Hanover , NH , USA
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4
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Single-Nucleotide Polymorphisms of the MSH2 and MLH1 Genes, Potential Molecular Markers for Susceptibility to the Development of Basal Cell Carcinoma in the Brazilian Population. Pathol Oncol Res 2017; 24:489-496. [DOI: 10.1007/s12253-017-0265-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 06/21/2017] [Indexed: 12/15/2022]
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5
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Knaack SA, Siahpirani AF, Roy S. A pan-cancer modular regulatory network analysis to identify common and cancer-specific network components. Cancer Inform 2014; 13:69-84. [PMID: 25374456 PMCID: PMC4213198 DOI: 10.4137/cin.s14058] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Revised: 09/22/2014] [Accepted: 09/24/2014] [Indexed: 12/19/2022] Open
Abstract
Many human diseases including cancer are the result of perturbations to transcriptional regulatory networks that control context-specific expression of genes. A comparative approach across multiple cancer types is a powerful approach to illuminate the common and specific network features of this family of diseases. Recent efforts from The Cancer Genome Atlas (TCGA) have generated large collections of functional genomic data sets for multiple types of cancers. An emerging challenge is to devise computational approaches that systematically compare these genomic data sets across different cancer types that identify common and cancer-specific network components. We present a module- and network-based characterization of transcriptional patterns in six different cancers being studied in TCGA: breast, colon, rectal, kidney, ovarian, and endometrial. Our approach uses a recently developed regulatory network reconstruction algorithm, modular regulatory network learning with per gene information (MERLIN), within a stability selection framework to predict regulators for individual genes and gene modules. Our module-based analysis identifies a common theme of immune system processes in each cancer study, with modules statistically enriched for immune response processes as well as targets of key immune response regulators from the interferon regulatory factor (IRF) and signal transducer and activator of transcription (STAT) families. Comparison of the inferred regulatory networks from each cancer type identified a core regulatory network that included genes involved in chromatin remodeling, cell cycle, and immune response. Regulatory network hubs included genes with known roles in specific cancer types as well as genes with potentially novel roles in different cancer types. Overall, our integrated module and network analysis recapitulated known themes in cancer biology and additionally revealed novel regulatory hubs that suggest a complex interplay of immune response, cell cycle, and chromatin remodeling across multiple cancers.
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Affiliation(s)
- Sara A Knaack
- Wisconsin Institute for Discovery, University of Wisconsin, Madison, WI, USA
| | - Alireza Fotuhi Siahpirani
- Wisconsin Institute for Discovery, University of Wisconsin, Madison, WI, USA. ; Department of Computer Sciences, University of Wisconsin, Madison, WI, USA
| | - Sushmita Roy
- Wisconsin Institute for Discovery, University of Wisconsin, Madison, WI, USA. ; Department of Biostatistics and Medical Informatics, University of Wisconsin, Madison, WI, USA
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6
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Caldon CE. Estrogen signaling and the DNA damage response in hormone dependent breast cancers. Front Oncol 2014; 4:106. [PMID: 24860786 PMCID: PMC4030134 DOI: 10.3389/fonc.2014.00106] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 04/28/2014] [Indexed: 12/21/2022] Open
Abstract
Estrogen is necessary for the normal growth and development of breast tissue, but high levels of estrogen are a major risk factor for breast cancer. One mechanism by which estrogen could contribute to breast cancer is via the induction of DNA damage. This perspective discusses the mechanisms by which estrogen alters the DNA damage response (DDR) and DNA repair through the regulation of key effector proteins including ATM, ATR, CHK1, BRCA1, and p53 and the feedback on estrogen receptor signaling from these proteins. We put forward the hypothesis that estrogen receptor signaling converges to suppress effective DNA repair and apoptosis in favor of proliferation. This is important in hormone-dependent breast cancer as it will affect processing of estrogen-induced DNA damage, as well as other genotoxic insults. DDR and DNA repair proteins are frequently mutated or altered in estrogen responsive breast cancer, which will further change the processing of DNA damage. Finally, the action of estrogen signaling on DNA damage is also relevant to the therapeutic setting as the suppression of a DDR by estrogen has the potential to alter the response of cancers to anti-hormone treatment or chemotherapy that induces DNA damage.
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Affiliation(s)
- C Elizabeth Caldon
- Genome and Replication Stability Group, The Kinghorn Cancer Centre, Garvan Institute of Medical Research , Sydney, NSW , Australia ; St Vincent's Clinical School, Faculty of Medicine, UNSW Australia , Sydney, NSW , Australia
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7
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Ji M, Liu Y, Yang S, Zhai D, Zhang D, Bai L, Wang Z, Yu J, Yu C, Cai Z. Puerarin suppresses proliferation of endometriotic stromal cells in part via differential recruitment of nuclear receptor coregulators to estrogen receptor-α. J Steroid Biochem Mol Biol 2013; 138:421-6. [PMID: 23907019 DOI: 10.1016/j.jsbmb.2013.07.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/29/2012] [Revised: 06/24/2013] [Accepted: 07/22/2013] [Indexed: 01/09/2023]
Abstract
BACKGROUND AND OBJECTIVES Puerarin, a phytoestrogen with a weak estrogenic effect, binds to estrogen receptors, thereby competing with 17β-estradiol and producing an anti-estrogenic effect. In our early clinical practice to treat endometriosis, a better therapeutic effect was achieved if the formula of traditional Chinese medicine included Radix puerariae. This study was to investigate whether puerarin could suppress the proliferation of endometriotic stromal cells (ESCs) and to further elucidate the potential mechanism. METHODS AND RESULTS The ESCs were successfully established. The effects of puerarin on the proliferation of ESCs, cell cycle and apoptosis were determined by Cell Counting Kit-8 assay and flow cytometry. The mRNA and protein levels of cyclin D1 and cdc25A were detected by real-time PCR and Western blot analysis. Coimmunoprecipitation was applied to examine the recruitment of nuclear receptor coregulators to the estrogen receptor-α. We found that puerarin can suppress estrogen-stimulated proliferation partly through down-regulating the transcription of cyclin D1 and cdc25A by promoting the recruitment of corepressors to estrogen receptor-α as well as limiting that of coactivators in ESCs. CONCLUSIONS Our data suggest that puerarin could suppress the proliferation of ESCs and could be a potential therapeutic agent for the treatment of endometriosis.
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Affiliation(s)
- Mei Ji
- Department of Traditional Chinese Medicine, Changhai Hospital, Second Military Medical University, Shanghai, China; Department of Obstetrics and Gynecology, Changhai Hospital, Second Military Medical University, Shanghai, China
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8
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Ying S, Dünnebier T, Si J, Hamann U. Estrogen receptor alpha and nuclear factor Y coordinately regulate the transcription of the SUMO-conjugating UBC9 gene in MCF-7 breast cancer cells. PLoS One 2013; 8:e75695. [PMID: 24086615 PMCID: PMC3785449 DOI: 10.1371/journal.pone.0075695] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 08/21/2013] [Indexed: 12/31/2022] Open
Abstract
UBC9 encodes a protein that conjugates small ubiquitin-related modifier (SUMO) to target proteins thereby changing their functions. Recently, it was noted that UBC9 expression and activity play a role in breast tumorigenesis and response to anticancer drugs. However, the underlying mechanism is poorly understood. To investigate the transcriptional regulation of the UBC9 gene, we identified and characterized its promoter and cis-elements. Promoter activity was tested using luciferase reporter assays. The binding of transcription factors to the promoter was detected by chromatin immunoprecipitation (ChIP), and their functional role was confirmed by siRNA knockdown. UBC9 mRNA and protein levels were measured by quantitative reverse transcription PCR and Western blot analysis, respectively. An increased expression of UBC9 mRNA and protein was found in MCF-7 breast cancer cells treated with 17β-estradiol (E2). Analysis of various deletion mutants revealed a 137 bp fragment upstream of the transcription initiation site to be sufficient for reporter gene transcription. Mutations of putative estrogen receptor α (ER-α) (one imperfect estrogen response element, ERE) and/or nuclear factor Y (NF-Y) binding sites (two CCAAT boxes) markedly reduced promoter activity. Similar results were obtained in ER-negative MDA-MB-231 cells except that the ERE mutation did not affect promoter activity. Additionally, promoter activity was stimulated upon E2 treatment and overexpression of ER-α or NF-YA in MCF-7 cells. ChIP confirmed direct binding of both transcription factors to the UBC9 promoter in vivo. Furthermore, UBC9 expression was diminished by ER-α and NF-Y siRNAs on the mRNA and protein levels. In conclusion, we identified the proximal UBC9 promoter and provided evidence that ER-α and NF-Y regulate UBC9 expression on the transcriptional level in response to E2 in MCF-7 cells. These findings may contribute to a better understanding of the regulation of UBC9 in ER-positive breast cancer and be useful for the development of cancer therapies targeting UBC9.
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Affiliation(s)
- Shibo Ying
- Molecular Genetics of Breast Cancer, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
| | - Thomas Dünnebier
- Molecular Genetics of Breast Cancer, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
| | - Jing Si
- Molecular Genetics of Breast Cancer, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
| | - Ute Hamann
- Molecular Genetics of Breast Cancer, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
- * E-mail:
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9
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MA LI, LIU YUEPING, GENG CUIZHI, QI XIAOWEI, JIANG JUN. Estrogen receptor β inhibits estradiol-induced proliferation and migration of MCF-7 cells through regulation of mitofusin 2. Int J Oncol 2013; 42:1993-2000. [DOI: 10.3892/ijo.2013.1903] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 03/15/2013] [Indexed: 11/06/2022] Open
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10
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Oviedo PJ, Sobrino A, Laguna-Fernandez A, Novella S, Tarín JJ, García-Pérez MA, Sanchís J, Cano A, Hermenegildo C. Estradiol induces endothelial cell migration and proliferation through estrogen receptor-enhanced RhoA/ROCK pathway. Mol Cell Endocrinol 2011; 335:96-103. [PMID: 20615453 DOI: 10.1016/j.mce.2010.06.020] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Revised: 06/30/2010] [Accepted: 06/30/2010] [Indexed: 01/29/2023]
Abstract
Migration and proliferation of endothelial cells are involved in re-endothelialization and angiogenesis, two important cardiovascular processes that are increased in response to estrogens. RhoA, a small GTPase which controls multiple cellular processes, is involved in the control of cell migration and proliferation. Our aim was to study the role of RhoA on estradiol-induced migration and proliferation and its dependence on estrogen receptors activity. Human umbilical vein endothelial cells were stimulated with estradiol, in the presence or absence of ICI 182780 (estrogen receptors antagonist) and Y-27632 (Rho kinase inhibitor). Estradiol increased Rho GEF-1 gene expression and RhoA (gene and protein expression and activity) in an estrogen receptor-dependent manner. Cell migration, stress fiber formation and cell proliferation were increased in response to estradiol and were also dependent on the estrogen receptors and RhoA activation. Estradiol decreased p27 levels, and significantly raised the expression of cyclins and CDK. These effects were counteracted by the use of either ICI 182780 or Y-27632. In conclusion, estradiol enhances the RhoA/ROCK pathway and increases cell cycle-related protein expression by acting through estrogen receptors. This results in an enhanced migration and proliferation of endothelial cells.
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Affiliation(s)
- Pilar J Oviedo
- Research Foundation, Hospital Clínico Universitario, Valencia, Spain
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11
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Shimizu T, Krebs S, Bauersachs S, Blum H, Wolf E, Miyamoto A. Actions and interactions of progesterone and estrogen on transcriptome profiles of the bovine endometrium. Physiol Genomics 2010; 42A:290-300. [PMID: 20876846 DOI: 10.1152/physiolgenomics.00107.2010] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The aim of our study was to analyze endometrial gene expression profiles in ovariectomized cows treated with estradiol and/or progesterone by using microarray analysis. Clustering of differentially expressed genes allowed separation into distinct hormone response patterns. These patterns could be classified into independent and interdependent actions of the steroid hormones estrogen and progesterone. The use of ovariectomized cows and external administration of hormones identified a set of genes whose regulation depends on a progesterone priming effect. The progesterone-primed estrogen response comprises gene functions such as migration, cell differentiation, and cell adhesion and therefore may play a crucial role in tissue remodeling, as one of its key regulators in the endometrium, TGFB2, is among this group of progesterone-primed genes. Functional annotation analysis of the estrogen-responsive gene clusters shows a clear dominance of functions such as cell cycle, morphogenesis, and differentiation. The functional profile of the progesterone-responsive clusters is less clear but nevertheless shows some important fertility-related terms like luteinization, oocyte maturation, and catecholamine metabolism. We looked for putative regulators of the steroid hormone response in endometrium by searching for enriched transcription factor binding sites in the promoter regions of the genes with similar hormone response profile. This analysis identified transcription factors such as SP1, NFYA, FOXA2, IRF2, ESR1, and NOBOX as candidate regulators of gene expression in bovine endometrium treated with steroid hormones. Taken together, our data provide novel insights into the regulation of bovine endometrial physiology by steroid hormones.
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Affiliation(s)
- Takashi Shimizu
- Graduate School of Animal and Food Hygiene, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Japan
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12
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Lu S, Archer MC. Sp1 coordinately regulates de novo lipogenesis and proliferation in cancer cells. Int J Cancer 2010; 126:416-25. [PMID: 19621387 DOI: 10.1002/ijc.24761] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Cancers express high levels of fatty acid synthase (FAS) from which they derive fatty acids for membrane biosynthesis to sustain cell proliferation. How cancer cells coordinate de novo lipogenesis and proliferation has not been investigated. Transcription factors Sp1, Sp3 and Sp4 are overexpressed in a variety of cancers and regulate gene expression by interacting with GC-rich Sp1 binding sites. Genes encoding FAS and cell cycle proteins such as CDC25A contain Sp1 binding sites in their promoters. We demonstrate by RNA interference that Sp1, Sp3 and Sp4 all play a role in regulating CDC25A expression and proliferation in human breast cancer cells. Only Sp1, however, also regulates FAS. Furthermore, mithramycin, which blocks Sp1 binding sites, decreased proliferation, inhibited CDC25A and FAS expression and reduced binding of Sp1 to the promoters of these genes as assessed by ChIP assays. Conversely, 17beta-estradiol (E(2)) increased proliferation and CDC25A and FAS expression along with increased binding of Sp1 to the promoters of the 2 genes. In addition, we showed that the expression of sterol regulatory element-binding protein-1c (SREBP-1c), the only transcription factor that has been shown to regulate genes of lipogenic enzymes in cancer cells, is also regulated by Sp1. Finally, we demonstrated that Sp1 plays a role in sustaining proliferation and FAS expression in colon as well as prostate cancer cells. Overall, these observations suggest that Sp1 coordinately regulates de novo lipogenesis and proliferation in cancer cells.
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Affiliation(s)
- Suying Lu
- Department of Nutritional Sciences, University of Toronto, ON, Canada
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13
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Gurtner A, Fuschi P, Magi F, Colussi C, Gaetano C, Dobbelstein M, Sacchi A, Piaggio G. NF-Y dependent epigenetic modifications discriminate between proliferating and postmitotic tissue. PLoS One 2008; 3:e2047. [PMID: 18431504 PMCID: PMC2295263 DOI: 10.1371/journal.pone.0002047] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2007] [Accepted: 03/13/2008] [Indexed: 02/03/2023] Open
Abstract
The regulation of gene transcription requires posttranslational modifications of histones that, in concert with chromatin remodeling factors, shape the structure of chromatin. It is currently under intense investigation how this structure is modulated, in particular in the context of proliferation and differentiation. Compelling evidence suggests that the transcription factor NF-Y acts as a master regulator of cell cycle progression, activating the transcription of many cell cycle regulatory genes. However, the underlying molecular mechanisms are not yet completely understood. Here we show that NF-Y exerts its effect on transcription through the modulation of the histone "code". NF-Y colocalizes with nascent RNA, while RNA polymerase II is I phosphorylated on serine 2 of the YSPTSPS repeats within its carboxyterminal domain and histones are carrying modifications that represent activation signals of gene expression (H3K9ac and PAN-H4ac). Comparing postmitotic muscle tissue from normal mice and proliferating muscles from mdx mice, we demonstrate by chromatin immunoprecipitation (ChIP) that NF-Y DNA binding activity correlates with the accumulation of acetylated histones H3 and H4 on promoters of key cell cycle regulatory genes, and with their active transcription. Accordingly, p300 is recruited onto the chromatin of NF-Y target genes in a NF-Y-dependent manner, as demonstrated by Re-ChIP. Conversely, the loss of NF-Y binding correlates with a decrease of acetylated histones, the recruitment of HDAC1, and a repressed heterochromatic state with enrichment of histones carrying modifications known to mediate silencing of gene expression (H3K9me3, H3K27me2 and H4K20me3). As a consequence, NF-Y target genes are downregulated in this context. In conclusion, our data indicate a role of NF-Y in modulating the structure and transcriptional competence of chromatin in vivo and support a model in which NF-Y-dependent histone "code" changes contribute to the proper discrimination between proliferating and postmitotic cells in vivo and in vitro.
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Affiliation(s)
- Aymone Gurtner
- Molecular Oncogenesis Laboratory, Experimental Oncology Department, Regina Elena Cancer Institute, Rome, Italy
| | - Paola Fuschi
- Molecular Oncogenesis Laboratory, Experimental Oncology Department, Regina Elena Cancer Institute, Rome, Italy
| | - Fiorenza Magi
- Molecular Oncogenesis Laboratory, Experimental Oncology Department, Regina Elena Cancer Institute, Rome, Italy
| | - Claudia Colussi
- Laboratory of Vascular Pathology, Istituto Dermopatico dell'Immacolata, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Rome, Italy
| | - Carlo Gaetano
- Laboratory of Vascular Pathology, Istituto Dermopatico dell'Immacolata, Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS), Rome, Italy
| | - Matthias Dobbelstein
- Department of Molecular Oncology, Göttingen Center of Molecular Biosciences (GZMB), Göttingen, Germany
| | - Ada Sacchi
- Molecular Oncogenesis Laboratory, Experimental Oncology Department, Regina Elena Cancer Institute, Rome, Italy
| | - Giulia Piaggio
- Molecular Oncogenesis Laboratory, Experimental Oncology Department, Regina Elena Cancer Institute, Rome, Italy
- Rome Oncogenomic Center, Experimental Oncology Department, Regina Elena Cancer Institute, Rome, Italy
- * E-mail:
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14
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Hockings JK, Degner SC, Morgan SS, Kemp MQ, Romagnolo DF. Involvement of a specificity proteins-binding element in regulation of basal and estrogen-induced transcription activity of the BRCA1 gene. Breast Cancer Res 2008; 10:R29. [PMID: 18377656 PMCID: PMC2397528 DOI: 10.1186/bcr1987] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2007] [Revised: 02/28/2008] [Accepted: 03/31/2008] [Indexed: 01/07/2023] Open
Abstract
INTRODUCTION Increased estrogen level has been regarded to be a risk factor for breast cancer. However, estrogen has also been shown to induce the expression of the tumor suppressor gene, BRCA1. Upregulation of BRCA1 is thought to be a feedback mechanism for controlling DNA repair in proliferating cells. Estrogens enhance transcription of target genes by stimulating the association of the estrogen receptor (ER) and related coactivators to estrogen response elements or to transcription complexes formed at activator protein (AP)-1 or specificity protein (Sp)-binding sites. Interestingly, the BRCA1 gene lacks a consensus estrogen response element. We previously reported that estrogen stimulated BRCA1 transcription through the recruitment of a p300/ER-alpha complex to an AP-1 site harbored in the proximal BRCA1 promoter. The purpose of the study was to analyze the contribution of cis-acting sites flanking the AP-1 element to basal and estrogen-dependent regulation of BRCA1 transcription. METHODS Using transfection studies with wild-type and mutated BRCA1 promoter constructs, electromobility binding and shift assays, and DNA-protein interaction and chromatin immunoprecipitation assays, we investigated the role of Sp-binding sites and cAMP response element (CRE)-binding sites harbored in the proximal BRCA1 promoter. RESULTS We report that in the BRCA1 promoter the AP-1 site is flanked upstream by an element (5'-GGGGCGGAA-3') that recruits Sp1, Sp3, and Sp4 factors, and downstream by a half CRE-binding motif (5'-CGTAA-3') that binds CRE-binding protein. In ER-alpha-positive MCF-7 cells and ER-alpha-negative Hela cells expressing exogenous ER-alpha, mutation of the Sp-binding site interfered with basal and estrogen-induced BRCA1 transcription. Conversely, mutation of the CRE-binding element reduced basal BRCA1 promoter activity but did not prevent estrogen activation. In combination with the AP-1/CRE sites, the Sp-binding domain enhanced the recruitment of nuclear proteins to the BRCA1 promoter. Finally, we report that the MEK1 (mitogen-activated protein kinase kinase-1) inhibitor PD98059 attenuated the recruitment of Sp1 and phosphorylated ER-alpha, respectively, to the Sp and AP-1 binding element. CONCLUSION These cumulative findings suggest that the proximal BRCA1 promoter segment comprises cis-acting elements that are targeted by Sp-binding and CRE-binding proteins that contribute to regulation of BRCA1 transcription.
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Affiliation(s)
- Jennifer K Hockings
- Cancer Biology Interdisciplinary Graduate Program, Department of Nutritional Sciences, The University of Arizona, E 4th Street, Tucson, Arizona 85721-0038, USA
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15
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Mrkonjic M, Raptis S, Green RC, Monga N, Daftary D, Dicks E, Younghusband HB, Parfrey PS, Gallinger SS, McLaughlin JR, Knight JA, Bapat B. MSH2 118T>C and MSH6 159C>T promoter polymorphisms and the risk of colorectal cancer. Carcinogenesis 2007; 28:2575-80. [PMID: 17942459 DOI: 10.1093/carcin/bgm229] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The most important indicator of colorectal cancer (CRC) risk is the presence of family history of the disease. Inherited genetic changes, such as single nucleotide polymorphisms, in key candidate genes may contribute to CRC risk. We investigated whether promoter polymorphisms in DNA mismatch repair (MMR) genes MSH2 and MSH6 are associated with the risk of CRC. We genotyped 929 CRC patients and 1098 control subjects from Ontario, and 467 patients and 344 controls from Newfoundland and Labrador, for two promoter polymorphisms in the MMR genes MSH2 and MSH6 using the fluorogenic 5' nuclease assay. We used unconditional logistic regression to evaluate the association between each polymorphism and CRC after adjusting for age and sex. The associations between polymorphisms and tumor clinicopathological features were evaluated with a Pearson's chi-squared test or Fisher's exact test. All statistical tests were two sided. We observed strong associations between the MSH2 -118T>C polymorphism and family history of CRC based on the Amsterdam criteria I (P = 0.005) and Amsterdam criteria I and II (P = 0.036) among cases from Ontario. This association was especially evident among female CRC patients in Ontario (for Amsterdam criteria I, and I and II combined, P = 0.003 and P = 0.0001, respectively). The MSH2 -118T>C polymorphism was associated with strong family history of CRC in Ontario patients.
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Affiliation(s)
- Miralem Mrkonjic
- Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario M5T 3L9, Canada
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Grimm SL, Rosen JM. Stop! In the name of transforming growth factor-beta: keeping estrogen receptor-alpha-positive mammary epithelial cells from proliferating. Breast Cancer Res 2007; 8:106. [PMID: 16834786 PMCID: PMC1779470 DOI: 10.1186/bcr1520] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Recent genetic and cell biological studies illustrate the importance of active transforming growth factor-beta signaling in preventing the proliferation of estrogen receptor-positive cells in the normal mammary gland, and suggest how the loss of this inhibition may be important in early breast cancer progression.
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Affiliation(s)
- Sandra L Grimm
- Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Jeffrey M Rosen
- Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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