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p53 Isoforms as Cancer Biomarkers and Therapeutic Targets. Cancers (Basel) 2022; 14:cancers14133145. [PMID: 35804915 PMCID: PMC9264937 DOI: 10.3390/cancers14133145] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 06/22/2022] [Indexed: 02/04/2023] Open
Abstract
Simple Summary The well-known tumor suppressor protein p53 plays important roles in tumor prevention through transcriptional regulation of its target genes. Reactivation of p53 activity has been a potent strategy for cancer treatment. Accumulating evidences indicate that p53 isoforms truncated/modified in the N- or C-terminus can modulate the p53 pathway in a p53-dependent or p53-independent manner. It is thus imperative to characterize the roles of the p53 isoforms in cancer development. This review illustrates how p53 isoforms participate in tumor development and/or suppression. It also summarizes the knowledge about the p53 isoforms as promising cancer biomarkers and therapeutic targets. Abstract This review aims to summarize the implications of the major isoforms of the tumor suppressor protein p53 in aggressive cancer development. The current knowledge of p53 isoforms, their involvement in cell-signaling pathways, and their interactions with other cellular proteins or factors suggests the existence of an intricate molecular network that regulates their oncogenic function. Moreover, existing literature about the involvement of the p53 isoforms in various cancers leads to the proposition of therapeutic solutions by altering the cellular levels of the p53 isoforms. This review thus summarizes how the major p53 isoforms Δ40p53α/β/γ, Δ133p53α/β/γ, and Δ160p53α/β/γ might have clinical relevance in the diagnosis and effective treatments of cancer.
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Madhu Krishna B, Chaudhary S, Mishra DR, Naik SK, Suklabaidya S, Adhya AK, Mishra SK. Estrogen receptor α dependent regulation of estrogen related receptor β and its role in cell cycle in breast cancer. BMC Cancer 2018; 18:607. [PMID: 29843638 PMCID: PMC5975398 DOI: 10.1186/s12885-018-4528-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 05/18/2018] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Breast cancer (BC) is highly heterogeneous with ~ 60-70% of estrogen receptor positive BC patient's response to anti-hormone therapy. Estrogen receptors (ERs) play an important role in breast cancer progression and treatment. Estrogen related receptors (ERRs) are a group of nuclear receptors which belong to orphan nuclear receptors, which have sequence homology with ERs and share target genes. Here, we investigated the possible role and clinicopathological importance of ERRβ in breast cancer. METHODS Estrogen related receptor β (ERRβ) expression was examined using tissue microarray slides (TMA) of Breast Carcinoma patients with adjacent normal by immunohistochemistry and in breast cancer cell lines. In order to investigate whether ERRβ is a direct target of ERα, we investigated the expression of ERRβ in short hairpin ribonucleic acid knockdown of ERα breast cancer cells by western blot, qRT-PCR and RT-PCR. We further confirmed the binding of ERα by electrophoretic mobility shift assay (EMSA), chromatin immunoprecipitation (ChIP), Re-ChIP and luciferase assays. Fluorescence-activated cell sorting analysis (FACS) was performed to elucidate the role of ERRβ in cell cycle regulation. A Kaplan-Meier Survival analysis of GEO dataset was performed to correlate the expression of ERRβ with survival in breast cancer patients. RESULTS Tissue microarray (TMA) analysis showed that ERRβ is significantly down-regulated in breast carcinoma tissue samples compared to adjacent normal. ER + ve breast tumors and cell lines showed a significant expression of ERRβ compared to ER-ve tumors and cell lines. Estrogen treatment significantly induced the expression of ERRβ and it was ERα dependent. Mechanistic analyses indicate that ERα directly targets ERRβ through estrogen response element and ERRβ also mediates cell cycle regulation through p18, p21cip and cyclin D1 in breast cancer cells. Our results also showed the up-regulation of ERRβ promoter activity in ectopically co-expressed ERα and ERRβ breast cancer cell lines. Fluorescence-activated cell sorting analysis (FACS) showed increased G0/G1 phase cell population in ERRβ overexpressed MCF7 cells. Furthermore, ERRβ expression was inversely correlated with overall survival in breast cancer. Collectively our results suggest cell cycle and tumor suppressor role of ERRβ in breast cancer cells which provide a potential avenue to target ERRβ signaling pathway in breast cancer. CONCLUSION Our results indicate that ERRβ is a negative regulator of cell cycle and a possible tumor suppressor in breast cancer. ERRβ could be therapeutic target for the treatment of breast cancer.
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Affiliation(s)
- B Madhu Krishna
- Cancer Biology Lab, Institute of Life Sciences, Nalco Square, Chandrasekharpur, Bhubaneswar, Odisha, 751023, India
| | - Sanjib Chaudhary
- Cancer Biology Lab, Institute of Life Sciences, Nalco Square, Chandrasekharpur, Bhubaneswar, Odisha, 751023, India.,Present address: Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center (UNMC), Omaha, NE, USA
| | - Dipti Ranjan Mishra
- Department of Gene Function & Regulation, Institute of Life Sciences, Nalco square, Chandrasekharpur, Bhubaneswar, Odisha, 751023, India
| | - Sanoj K Naik
- Cancer Biology Lab, Institute of Life Sciences, Nalco Square, Chandrasekharpur, Bhubaneswar, Odisha, 751023, India
| | - S Suklabaidya
- Tumor Microenvironment and Animal Models Lab, Department of Translational Research and Technology Development, Institute of Life Sciences, Nalco square, Chandrasekharpur, Bhubaneswar, Odisha, 751023, India
| | - A K Adhya
- Department of Pathology, Kalinga Institute of Medical Sciences, Chandaka Industrial Estate, KIIT Rd, Patia, Bhubaneswar, Odisha, India
| | - Sandip K Mishra
- Cancer Biology Lab, Institute of Life Sciences, Nalco Square, Chandrasekharpur, Bhubaneswar, Odisha, 751023, India.
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Aleck K, Hallman K, Quigley M, Lloyd V, Szmyd M, Ruskin D, Bedgood T, Dinda S. Effects of Atrial Natriuretic Peptide on p53 and Estrogen Receptor in Breast Cancer Cells. Biores Open Access 2017; 6:141-150. [PMID: 29098120 PMCID: PMC5665415 DOI: 10.1089/biores.2017.0009] [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] [Indexed: 12/28/2022] Open
Abstract
The atrial natriuretic peptide (ANP) hormone is secreted by cardiac atrial myocytes and acts to regulate blood pressure homeostasis in humans. Previous research indicates ANP treatment significantly decreases the proliferation of human prostate cancer cells, pancreatic adenocarcinoma, and breast cancer cells. Minimal studies have been conducted with regard to ANP regulating tumor suppressor genes and steroid hormone receptors in breast cancer cells. Our study analyzed the effects of ANP in combination with 17β-estradiol (E2) and antiestrogen treatments on p53 and ERα levels in T-47D breast cancer cells. Preliminary studies through Western blot analysis showed that ANP treatment decreases p53 and ERα expression levels in a concentration-dependent (10-100 nM) manner. Treatment with ANP alone, at a 100 nM concentration, causes a decrease of p53 and ERα expression compared with Cs (control stripped), but with E2 and antiestrogen combinations, expression of both protein levels decreased compared with treatments without ANP. Combined treatment with E2, an estrogen antagonist, and ANP decreased cellular proliferation compared with treatments without ANP, except in the case of raloxifene (RAL). Our studies indicate that ANP has potential as a therapeutic breast cancer treatment and should inspire further studies on the molecular mechanism of ANP in T-47D breast cancer cells.
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Affiliation(s)
- Katie Aleck
- Department of Biomedical Diagnostic Therapeutic Sciences, School of Health Sciences, Institute for Stem Cell Research and Center for Biomedical Research, Oakland University, Rochester, Michigan
| | - Kelly Hallman
- Department of Biomedical Diagnostic Therapeutic Sciences, School of Health Sciences, Institute for Stem Cell Research and Center for Biomedical Research, Oakland University, Rochester, Michigan
| | - Meghan Quigley
- Department of Biomedical Diagnostic Therapeutic Sciences, School of Health Sciences, Institute for Stem Cell Research and Center for Biomedical Research, Oakland University, Rochester, Michigan
| | - Victoria Lloyd
- Department of Biomedical Diagnostic Therapeutic Sciences, School of Health Sciences, Institute for Stem Cell Research and Center for Biomedical Research, Oakland University, Rochester, Michigan
| | - Monica Szmyd
- Department of Biomedical Diagnostic Therapeutic Sciences, School of Health Sciences, Institute for Stem Cell Research and Center for Biomedical Research, Oakland University, Rochester, Michigan
| | - Dana Ruskin
- Department of Biomedical Diagnostic Therapeutic Sciences, School of Health Sciences, Institute for Stem Cell Research and Center for Biomedical Research, Oakland University, Rochester, Michigan
| | - Tyler Bedgood
- Department of Biomedical Diagnostic Therapeutic Sciences, School of Health Sciences, Institute for Stem Cell Research and Center for Biomedical Research, Oakland University, Rochester, Michigan
| | - Sumi Dinda
- Department of Biomedical Diagnostic Therapeutic Sciences, School of Health Sciences, Institute for Stem Cell Research and Center for Biomedical Research, Oakland University, Rochester, Michigan
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Dinda S, Sanchez A, Moudgil VK. Effects of LY117018 (a SERM analog of raloxifene) on tumor suppressor proteins and proliferation of breast cancer cells. Horm Mol Biol Clin Investig 2015; 2:211-7. [PMID: 25961194 DOI: 10.1515/hmbci.2010.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Accepted: 01/12/2010] [Indexed: 11/15/2022]
Abstract
We have previously shown that presence of estradiol (E2) in the growth medium causes (i) proliferation of T47D breast cancer cells, (ii) elevation of p53 levels, and (iii) hyperphos-phorylation of retinoblastoma protein (pRb). In the present study, we examined the expression of p53, phosphorylation state of pRb and proliferation of T47D cells in the presence of LY117018 (Courtesy of Lilly Research Laboratories), an analog of raloxifene, which is a known selective estrogen receptor modulator (SERM). The cells grown in charcoal-treated serum were treated with 1 nM E2 or different concentrations of LY117018 for 24 h. E2 or LY117018 treatments caused a 2- to 3-fold increase in the level of p53 and hyperphosphorylation of pRb. E2 treatment increased cell proliferation, whereas LY117018 treatment had no such effect but inhibited the E2-dependent cell proliferation. E2 and LY117018 treatments of T47D cells also caused differential effects on intracellular structures. Thus, LY117018 treatment induces changes in the level/activity of p53 and pRb and ultrastructure of T47D cells. Importantly, LY11708 inhibits estrogen-induced cell proliferation while mimicking E2 actions on p53 induction and pRb phosphorylation. The SERM also induced structural alterations in the T47D cells.
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TRIM25 has a dual function in the p53/Mdm2 circuit. Oncogene 2015; 34:5729-38. [PMID: 25728675 DOI: 10.1038/onc.2015.21] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Revised: 12/17/2014] [Accepted: 12/19/2014] [Indexed: 12/20/2022]
Abstract
P53 is an important tumor suppressor that, upon activation, induces growth arrest and cell death. Control of p53 is thus of prime importance for proliferating cells, but also for cancer therapy, where p53 activity contributes to the eradication of tumors. Mdm2 functionally inhibits p53 and targets the tumor suppressor protein for degradation. In a genetic screen, we identified TRIM25 as a novel regulator of p53 and Mdm2. TRIM25 increased p53 and Mdm2 abundance by inhibiting their ubiquitination and degradation in 26 S proteasomes. TRIM25 co-precipitated with p53 and Mdm2 and interfered with the association of p300 and Mdm2, a critical step for p53 polyubiquitination. Despite the increase in p53 levels, p53 activity was inhibited in the presence of TRIM25. Downregulation of TRIM25 resulted in an increased acetylation of p53 and p53-dependent cell death in HCT116 cells. Upon genotoxic insults, TRIM25 dampened the p53-dependent DNA damage response. The downregulation of TRIM25 furthermore resulted in massive apoptosis during early embryogenesis of medaka, which was rescued by the concomitant downregulation of p53, demonstrating the functional relevance of the regulation of p53 by TRIM25 in an organismal context.
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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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Berger C, Qian Y, Chen X. The p53-estrogen receptor loop in cancer. Curr Mol Med 2014; 13:1229-40. [PMID: 23865427 DOI: 10.2174/15665240113139990065] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 06/19/2013] [Accepted: 07/11/2013] [Indexed: 12/30/2022]
Abstract
Tumor suppressor p53 maintains genome stability by regulating diverse cellular functions including cell cycle arrest, apoptosis, senescence and metabolic homeostasis. Mutations in the p53 gene occur in almost all human cancers with a frequency of up to 80%. However, it is only 20% in breast cancers, 18% in endometrial cancers and 1.5% in cervical cancers. Estrogen receptor alpha (ERα) plays a pivotal role in hormone-dependent cancer development and the status of ERα is used for designing treatment strategy and for prognosis. A closer look at the cross-talk between p53 and ERα has revealed that their activities are mutually regulated. This review will summarize the current body of knowledge on p53, ERα and ERβ in cancer. Clinical correlations between estrogen receptors and p53 status have also been reported. Thus, this review will discuss the relationship between p53 and ERs at both the molecular and clinical levels.
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Affiliation(s)
- C Berger
- Comparative Oncology Laboratory, University of California, Davis, CA 95616, USA
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Ford NA, Devlin KL, Lashinger LM, Hursting SD. Deconvoluting the obesity and breast cancer link: secretome, soil and seed interactions. J Mammary Gland Biol Neoplasia 2013; 18:267-75. [PMID: 24091864 PMCID: PMC3874287 DOI: 10.1007/s10911-013-9301-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Accepted: 09/24/2013] [Indexed: 12/20/2022] Open
Abstract
Obesity is associated with increased risk of breast cancer in postmenopausal women and is linked with poor prognosis in pre- and postmenopausal breast cancer patients. The mechanisms underlying the obesity-breast cancer connection are becoming increasingly clear and provide multiple opportunities for primary to tertiary prevention. Several obesity-related host factors can influence breast tumor initiation, progression and/or response to therapy, and these have been implicated as key contributors to the complex effects of obesity on cancer incidence and outcomes. These host factors include components of the secretome, including insulin, insulin-like growth factor-1, leptin, adiponectin, steroid hormones, cytokines, vascular regulators, and inflammation-related molecules, as well as the cellular and structural components of the tumor microenvironment. These secreted and structural host factors are extrinsic to, and interact with, the intrinsic molecular characteristics of breast cancer cells (including breast cancer stem cells), and each will be considered in the context of energy balance and as potential targets for cancer prevention.
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Affiliation(s)
- Nikki A. Ford
- Department of Nutritional Sciences, University of Texas at Austin, Austin, Texas 78722, USA
| | - Kaylyn L. Devlin
- Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas 78722, USA
| | - Laura M. Lashinger
- Department of Nutritional Sciences, University of Texas at Austin, Austin, Texas 78722, USA
| | - Stephen D. Hursting
- Department of Nutritional Sciences, University of Texas at Austin, Austin, Texas 78722, USA
- Department of Molecular Carcinogenesis, University of Texas MD Anderson Cancer Center, Science Park, Smithville, TX 78957, USA
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Ford NA, Dunlap SM, Wheatley KE, Hursting SD. Obesity, independent of p53 gene dosage, promotes mammary tumor progression and upregulates the p53 regulator microRNA-504. PLoS One 2013; 8:e68089. [PMID: 23840816 PMCID: PMC3696069 DOI: 10.1371/journal.pone.0068089] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Accepted: 05/24/2013] [Indexed: 12/21/2022] Open
Abstract
Obesity, prevalent in >35% of US women, is an established risk and progression factor for postmenopausal breast cancer, and strategies to break the obesity-breast cancer link are urgently needed. Approximately 30% of breast cancers carry p53 tumor suppressor gene alterations; however, the effects of obesity on breast cancer progression in relation to p53 gene dosage are unclear. Using murine models of postmenopausal breast cancer, we characterized the interactive effects of diet-induced obesity (DIO) and p53 gene dosage on mammary tumor growth and associated p53-related regulatory mechanisms. Ovariectomized C57BL/6 mice were randomly assigned to receive a DIO or control diet, and (at 10 weeks) orthotopic injection of MMTV-Wnt-1 p53+/− or MMTV-Wnt-1 p53+/+ mammary tumor cells (n = 20 mice per diet and genotype group). DIO and control diets produced distinct phenotypes (mean percent body fat at 10 weeks: 57% and 39%, respectively, P<0.001). Regardless of phenotype, time to first palpable tumor was 57% less for Wnt-1 p53+/− than Wnt-1 p53+/+ tumors. Regardless of tumoral p53 genotype, DIO (relative to control) increased tumor burden, tumor cell proliferation (Ki-67), severity of tumor pathology, local tissue invasion, epithelial-to-mesenchymal transition (EMT) programming, and tumoral microRNA-504 (a negative regulator of p53) expression; and suppressed p53, p21, and estrogen receptor-alpha protein expression. These findings in murine models of postmenopausal breast cancer suggest that obesity may augment procancer effects related to p53 gene alterations. Furthermore, microRNA-504, an obesity-responsive negative regulator of p53 and putative EMT regulator, may represent a novel molecular target for breaking the obesity-breast cancer link.
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Affiliation(s)
- Nikki A. Ford
- Department of Nutritional Sciences University of Texas at Austin, Austin, Texas, United States of America
| | - Sarah M. Dunlap
- Department of Nutritional Sciences University of Texas at Austin, Austin, Texas, United States of America
| | - Karrie E. Wheatley
- Department of Nutritional Sciences University of Texas at Austin, Austin, Texas, United States of America
| | - Stephen D. Hursting
- Department of Nutritional Sciences University of Texas at Austin, Austin, Texas, United States of America
- Department of Molecular Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Smithville, Texas, United States of America
- * E-mail:
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Dueñas M, Santos M, Aranda JF, Bielza C, Martínez-Cruz AB, Lorz C, Taron M, Ciruelos EM, Rodríguez-Peralto JL, Martín M, Larrañaga P, Dahabreh J, Stathopoulos GP, Rosell R, Paramio JM, García-Escudero R. Mouse p53-deficient cancer models as platforms for obtaining genomic predictors of human cancer clinical outcomes. PLoS One 2012; 7:e42494. [PMID: 22880004 PMCID: PMC3413665 DOI: 10.1371/journal.pone.0042494] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Accepted: 07/06/2012] [Indexed: 11/18/2022] Open
Abstract
Mutations in the TP53 gene are very common in human cancers, and are associated with poor clinical outcome. Transgenic mouse models lacking the Trp53 gene or that express mutant Trp53 transgenes produce tumours with malignant features in many organs. We previously showed the transcriptome of a p53-deficient mouse skin carcinoma model to be similar to those of human cancers with TP53 mutations and associated with poor clinical outcomes. This report shows that much of the 682-gene signature of this murine skin carcinoma transcriptome is also present in breast and lung cancer mouse models in which p53 is inhibited. Further, we report validated gene-expression-based tests for predicting the clinical outcome of human breast and lung adenocarcinoma. It was found that human patients with cancer could be stratified based on the similarity of their transcriptome with the mouse skin carcinoma 682-gene signature. The results also provide new targets for the treatment of p53-defective tumours.
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Affiliation(s)
| | | | | | - Concha Bielza
- Departamento de Inteligencia Artificial, Universidad Politécnica de Madrid, Boadilla del Monte, Madrid, Spain
| | | | - Corina Lorz
- Molecular Oncology Unit, CIEMAT, Madrid, Spain
| | - Miquel Taron
- Catalan Institute of Oncology, Hospital Germans Trias i Pujol, Badalona, Spain
| | - Eva M. Ciruelos
- Medical Oncology Department, Hospital Universitario 12 de Octubre, Madrid, Spain
| | - José L. Rodríguez-Peralto
- Pathology Department, Hospital Universitario 12 de Octubre, and Instituto de Investigación Hospital 12 de Octubre i+12, Universidad Complutense, Madrid, Spain
| | - Miguel Martín
- Hospital General Gregorio Marañón, Universidad Complutense, Madrid, Spain
| | - Pedro Larrañaga
- Departamento de Inteligencia Artificial, Universidad Politécnica de Madrid, Boadilla del Monte, Madrid, Spain
| | | | | | - Rafael Rosell
- Catalan Institute of Oncology, Hospital Germans Trias i Pujol, Badalona, Spain
| | - Jesús M. Paramio
- Molecular Oncology Unit, CIEMAT, Madrid, Spain
- * E-mail: (RG-E); (JMP)
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Abbondanza C, De Rosa C, D'Arcangelo A, Pacifico M, Spizuoco C, Piluso G, Di Zazzo E, Gazzerro P, Medici N, Moncharmont B, Puca GA. Identification of a functional estrogen-responsive enhancer element in the promoter 2 of PRDM2 gene in breast cancer cell lines. J Cell Physiol 2012; 227:964-75. [PMID: 21503890 DOI: 10.1002/jcp.22803] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The retinoblastoma protein-interacting zinc-finger (RIZ) gene, also known as PRDM2, encodes two protein products, RIZ1 and RIZ2, differing for the presence of a 202 aa domain, called PR domain, at the N-terminus of the RIZ1 molecule. While the histone H3 K9 methyltransferase activity of RIZ1 is associated with the negative control of cell proliferation, no information is currently available on either expression regulation of the RIZ2 form or on its biological activity. RIZ proteins act as ER co-activators and promote optimal estrogen response in female reproductive tissues. In estrogen-responsive cells, 17-β estradiol modulates RIZ gene expression producing a shift in the balanced expression of the two forms. Here, we demonstrate that an estrogen-responsive element (ERE) within the RIZ promoter 2 is regulated in a ligand-specific manner by ERα, through both the AF1 and AF2 domains. The pattern of ERα binding, histone H4 acetylation, and histone H3 cyclical methylation of lysine 9 was comparable to other estrogen-regulated promoters. Association of topoisomerase IIβ with the RIZ promoter 2 confirmed the transcriptional activation induced by estrogen. We hypothesize that RIZ2, acting as a negative regulator of RIZ1 function, mediates the proliferative effect of estrogen through regulation of survival and differentiation gene expression.
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Affiliation(s)
- Ciro Abbondanza
- Dipartimento di Patologia generale, Seconda Università degli studi di Napoli, Naples, Italy
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Functional Significance of Aurora Kinase A Regulatory Interactions with p53–ERα Complex in Human Breast Cancer Cells. Discov Oncol 2011; 2:117-24. [DOI: 10.1007/s12672-011-0070-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
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Fuchs-Young R, Shirley SH, Lambertz I, Colby JKL, Tian J, Johnston D, Gimenez-Conti IB, Donehower LA, Conti CJ, Hursting SD. P53 genotype as a determinant of ER expression and tamoxifen response in the MMTV-Wnt-1 model of mammary carcinogenesis. Breast Cancer Res Treat 2010; 130:399-408. [PMID: 21191649 DOI: 10.1007/s10549-010-1308-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2009] [Accepted: 12/10/2010] [Indexed: 10/18/2022]
Abstract
Clinical studies show that estrogen receptor-α (ER) expressing tumors tend to have better prognosis, respond to antiestrogen therapy and have wild-type p53. Conversely, tumors with inactivating mutations in p53 tend to have worse outcomes and to be ER-negative and unresponsive to antihormone treatment. Previous studies from our laboratory have shown that p53 regulates ER expression transcriptionally, by binding the ER promoter and forming a complex with CARM1, CBP, c-Jun, RNA polymerase II and Sp1. In this study, the MMTV-Wnt-1 transgenic mouse model was used to demonstrate that p53 regulation of ER expression and function is not solely an in vitro phenomenon, but it is also operational in mammary tumorigenesis in vivo. The expression of ER and the ability to respond to tamoxifen were determined in mammary tumors arising in p53 wild type (WT) or p53 heterozygous (HT) animals carrying the Wnt-1 transgene. In p53 WT mice, development of ER-positive tumors was delayed by tamoxifen treatment, while tumors arising in p53 HT mice had significantly reduced levels of ER and were not affected by tamoxifen. P53 null tumors were also found in the p53 HT mice and these tumors were ER-negative. ER expression was upregulated in mouse mammary tumor cell lines following transfection with WT p53 or treatment with doxorubicin. These data demonstrate that p53 regulates ER expression in vivo, and affects response to tamoxifen. Results also provide an explanation for the concordant relationship between these prognostic proteins in human breast tumors.
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Affiliation(s)
- Robin Fuchs-Young
- Department of Molecular Carcinogenesis, The Virginia Harris Cockrell Cancer Research Center at The University of Texas MD Anderson Cancer Center, Science Park Research Division, 1808 Park Road 1C, Smithville, TX 78957, USA.
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Fernandez-Cuesta L, Anaganti S, Hainaut P, Olivier M. p53 status influences response to tamoxifen but not to fulvestrant in breast cancer cell lines. Int J Cancer 2010; 128:1813-21. [DOI: 10.1002/ijc.25512] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Estrogen levels act as a rheostat on p53 levels and modulate p53-dependent responses in breast cancer cell lines. Breast Cancer Res Treat 2010; 125:35-42. [PMID: 20221692 DOI: 10.1007/s10549-010-0819-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Accepted: 02/24/2010] [Indexed: 02/06/2023]
Abstract
A large proportion of breast cancers expresses the estrogen receptor alpha (ERα) and are dependent on estrogens for their proliferation and survival. The tumor suppressor TP53 encodes the p53 protein, an important mediator of the anti-proliferative and apoptotic effects of several treatments used for breast cancer. A significant proportions of breast tumors (20-30%) carry mutations in TP53 gene and these mutations are associated with poor survival and poor response to several types of chemotherapeutic treatments. While there is mounting evidence for functional interactions between p53 and ERα pathways in breast and other tissues, the impact of these interactions on response to chemotherapy and anti-hormone treatments remain largely unknown. Here, using estrogen-dependent breast cancer cell lines with different p53 status, we show that estrogens, through ERα, influence p53 protein levels and activities. Estrogen deprivation reduced, while estradiol increased p53 levels, in a time and dose-dependent manner. Both wild-type and endogenously expressed mutant p53 proteins were affected. This reduction in p53 protein levels resulted in reduced p53-dependent responses induced by DNA damage in p53 wild-type cells, lowering the capacity of doxorubicine to induce apoptosis. The p53 response appeared to be quantitatively but not qualitatively affected. These results suggest that ERα activity is required for a strong p53 response in estrogen-dependent breast cancer cells. These results are in line with previous observations that we made in a clinical series, where a larger effect of TP53 mutation status was found for patient survival in cases with progesterone receptor positive status, a marker of a functional ERα pathway. It would thus be important to further characterize the influence of ERα pathway on the predictive value of TP53 mutation status in specifically designed clinical trials, as it may open perspectives for improving breast cancer treatment.
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16
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Shirley SH, Rundhaug JE, Tian J, Cullinan-Ammann N, Lambertz I, Conti CJ, Fuchs-Young R. Transcriptional regulation of estrogen receptor-alpha by p53 in human breast cancer cells. Cancer Res 2009; 69:3405-14. [PMID: 19351845 DOI: 10.1158/0008-5472.can-08-3628] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Estrogen receptor alpha (ER) and p53 are critical prognostic indicators in breast cancer. Loss of functional p53 is correlated with poor prognosis, ER negativity, and resistance to antiestrogen treatment. Previously, we found that p53 genotype was correlated with ER expression and response to tamoxifen in mammary tumors arising in mouse mammary tumor virus-Wnt-1 transgenic mice. These results lead us to hypothesize that p53 may regulate ER expression. To test this, MCF-7 cells were treated with doxorubicin or ionizing radiation, both of which stimulated a 5-fold increase in p53 expression. ER expression was also increased 4-fold over a 24-h time frame. In cells treated with small interfering RNA (siRNA) targeting p53, expression of both p53 and ER was significantly reduced (>60%) by 24 h. Induction of ER by DNA-damaging agents was p53 dependent as either ionizing radiation or doxorubicin failed to up-regulate ER after treatment with p53-targeting siRNA. To further investigate whether p53 directly regulates transcription of the ER gene promoter, MCF-7 cells were transiently transfected with a wild-type (WT) p53 expression vector along with a luciferase reporter containing the proximal promoter of ER. In cells transfected with WT p53, transcription from the ER promoter was increased 8-fold. Chromatin immunoprecipitation assays showed that p53 was recruited to the ER promoter along with CARM1, CBP, c-Jun, and Sp1 and that this multifactor complex was formed in a p53-dependent manner. These data show that p53 regulates ER expression through transcriptional control of the ER promoter, accounting for their concordant expression in human breast cancer.
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Affiliation(s)
- Stephanie Harkey Shirley
- The University of Texas M. D. Anderson Cancer Center, Science Park Research Division, Smithville, Texas 78957, USA
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17
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Wickramasinghe NS, Manavalan TT, Dougherty SM, Riggs KA, Li Y, Klinge CM. Estradiol downregulates miR-21 expression and increases miR-21 target gene expression in MCF-7 breast cancer cells. Nucleic Acids Res 2009; 37:2584-95. [PMID: 19264808 PMCID: PMC2677875 DOI: 10.1093/nar/gkp117] [Citation(s) in RCA: 278] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Select changes in microRNA (miRNA) expression correlate with estrogen receptor α (ERα) expression in breast tumors. miR-21 is higher in ERα positive than negative tumors, but no one has examined how estradiol (E2) regulates miR-21 in breast cancer cells. Here we report that E2 inhibits miR-21 expression in MCF-7 human breast cancer cells. The E2-induced reduction in miR-21 was inhibited by 4-hydroxytamoxifen (4-OHT), ICI 182 780 (Faslodex), and siRNA ERα indicating that the suppression is ERα-mediated. ERα and ERβ agonists PPT and DPN inhibited and 4-OHT increased miR-21 expression. E2 increased luciferase activity from reporters containing the miR-21 recognition elements from the 3′-UTRs of miR-21 target genes, corroborating that E2 represses miR-21 expression resulting in a loss of target gene suppression. The E2-mediated decrease in miR-21 correlated with increased protein expression of endogenous miR-21-targets Pdcd4, PTEN and Bcl-2. siRNA knockdown of ERα blocked the E2-induced increase in Pdcd4, PTEN and Bcl-2. Transfection of MCF-7 cells with antisense (AS) to miR-21 mimicked the E2-induced increase in Pdcd4, PTEN and Bcl-2. These results are the first to demonstrate that E2 represses the expression of an oncogenic miRNA, miR-21, by activating estrogen receptor in MCF-7 cells.
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Affiliation(s)
- Nalinie S Wickramasinghe
- Department of Biochemistry & Molecular Biology, Center for Genetics and Molecular Medicine, University of Louisville School of Medicine, Louisville, KY 40292, USA
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18
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Riggins RB, Bouton AH, Liu MC, Clarke R. Antiestrogens, aromatase inhibitors, and apoptosis in breast cancer. VITAMINS AND HORMONES 2005; 71:201-37. [PMID: 16112269 DOI: 10.1016/s0083-6729(05)71007-4] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Antiestrogens have been the therapeutic agents of choice for breast cancer patients whose tumors express estrogen receptors, regardless of menopausal status. Unfortunately, many patients will eventually develop resistance to these drugs. Antiestrogens primarily act by preventing endogenous estrogen from activating estrogen receptors and promoting cell growth, which can ultimately lead to tumor cell death. Understanding the mechanisms by which antiestrogens cause cell death or apoptosis is critical to our efforts to develop ways to circumvent resistance. This article focuses on antiestrogen-induced apoptosis both in vitro and in vivo. We review the clinical utility of both antiestrogens and aromatase inhibitors and their apoptogenic mechanisms in cell culture models. Among the key signaling components discussed are the roles of Bcl-2 family members, several cytokines, and their receptors, p53, nuclear factor kappa B (NFkappaB), IRF-1, phosphatidylinositol 3-kinase (PI3K)/Akt, and specific caspases. Finally, we discuss the evidence supporting a role for apoptotic defects in acquired and de novo antiestrogen resistance.
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Affiliation(s)
- Rebecca B Riggins
- Department of Oncology and Physiology, Lombardi Comprehensive Cancer Center, Georgetown University Medical Center, Washington, DC 20057, USA
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19
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Maia H, Maltez A, Studart E, Athayde C, Coutinho EM. Ki-67, Bcl-2 and p53 expression in endometrial polyps and in the normal endometrium during the menstrual cycle. BJOG 2004; 111:1242-7. [PMID: 15521869 DOI: 10.1111/j.1471-0528.2004.00406.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To determine the presence of proteins related to proliferation (Ki-67) and apoptosis (Bcl-2, p53) in endometrial polyps and normal endometrium during the menstrual cycle. DESIGN Retrospective study using paraffin embedded tissue. SETTING Hospital affiliated to the university. POPULATION Premenopausal patients with endometrial polyps. METHODS Seventy-eight premenopausal patients in different phases of the menstrual cycle were submitted to polypectomy using the Bettocchi hysteroscope. Immunohistochemistry was used to detect the expression of these proteins in endometrial polyps. One hundred and eighteen normal endometrial biopsies were used as controls. MAIN OUTCOME MEASURES Detection of Bcl-2 and Ki-67 expression by immunohistochemistry. RESULTS In endometrial polyps, Ki-67, p53 and Bcl-2 expression was detected with more frequency during the proliferative than during the luteal phase of the cycle. Similar findings were observed in the normal endometrium. CONCLUSION Endometrial polyps undergo cyclic changes in the expression of their proteins related to proliferation and apoptosis during the menstrual cycle, similar to those of the cycling endometrium.
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Affiliation(s)
- Hugo Maia
- CEPARH, Rua Caetano Moura 35, 402310-341 Salvador, Bahia, Brazil
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20
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Sengupta S, Wasylyk B. Physiological and pathological consequences of the interactions of the p53 tumor suppressor with the glucocorticoid, androgen, and estrogen receptors. Ann N Y Acad Sci 2004; 1024:54-71. [PMID: 15265773 DOI: 10.1196/annals.1321.005] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The p53 tumor suppressor plays a key role in protection from the effects of different physiological stresses (DNA damage, hypoxia, transcriptional defects, etc.), and loss of its activity has dire consequences, such as cancer. Its activity is finely tuned through interactions with other important regulatory circuits in the cell. Recently, striking evidence has emerged for crosstalk with another class of important regulators, the steroid hormone receptors, and in particular the glucocorticoid (GR), androgen (AR), and estrogen (ER) receptors. These receptors are important in maintaining homeostasis in response to internal and external stresses (GR) and in the development, growth, and maintenance of the male and female reproductive systems (AR and ER, respectively). We review how p53 interacts closely with these receptors, to the extent that they share the same E3 ubiquitin ligase, the MDM2 oncoprotein. We discuss the different physiological contexts in which such interactions occur, and also how these interactions have been undermined in various pathological situations. We will describe future areas for research, with special emphasis on GR, and how certain common features, such as cytoplasmic anchoring of p53 by the receptors, may become targets for the development of therapeutic interventions. Given the importance of GR in inflammation, erythropoiesis, and autoimmune diseases, and the importance of AR and ER in prostate and breast cancer (respectively), the studies on p53 interactions with the steroid receptors will be an important domain in the near future.
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Affiliation(s)
- Sagar Sengupta
- Laboratory of Human Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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21
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Dhillon NK, Mudryj M. Cyclin E overexpression enhances cytokine-mediated apoptosis in MCF7 breast cancer cells. Genes Immun 2003; 4:336-42. [PMID: 12847548 DOI: 10.1038/sj.gene.6363973] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Cyclin E, the regulatory component of the cyclin E/cyclin-dependent kinase (CDK) complex, is required for proliferation and overexpression of this cyclin is associated with many types of human tumors. To elucidate the mechanism by which cyclin E overexpression promotes tumorigenesis, cyclin E was overexpressed in two breast cancer lines: MCF7 and T47D. Cells overexpressing cyclin E display a marked decrease in the expression of Bcl-2, an antiapoptotic protein, and increased levels of the proapoptotic proteins Bad and Bax. The levels of Bcl-X(L) and Mcl-1 remain unchanged. Since the homeostasis of pro- and antiapoptotic proteins was altered, we asked if cyclin E overexpression modifies responses to cytokines. MCF7 cyclin E overexpressing cells have an enhanced sensitivity to Fas, TRAIL, and TNF-alpha-induced apoptosis. T47D cells overexpressing cyclin E have a significant increase in TNF-alpha and TRAIL-induced apoptosis. In conclusion, our results provide a link between expression of cyclin E, deregulation of Bcl-2, and an altered response to cytokine-mediated apoptosis.
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Affiliation(s)
- N K Dhillon
- Department of Medical Microbiology and Immunology, School of Medicine, University of California, Davis, CA 95616, USA
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22
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Qin C, Nguyen T, Stewart J, Samudio I, Burghardt R, Safe S. Estrogen up-regulation of p53 gene expression in MCF-7 breast cancer cells is mediated by calmodulin kinase IV-dependent activation of a nuclear factor kappaB/CCAAT-binding transcription factor-1 complex. Mol Endocrinol 2002; 16:1793-809. [PMID: 12145335 DOI: 10.1210/me.2002-0006] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
This study investigates the mechanism of hormonal regulation of p53 gene expression in MCF-7 human breast cancer cells. 17beta-Estradiol (E2) induced a 2-fold increase in p53 mRNA levels and a 2- to 3-fold increase in p53 protein. Analysis of the p53 gene promoter has identified a minimal E2-responsive region at -106 to -40, and mutation/deletion analysis of the promoter showed that motifs that bind CCAAT-binding transcription factor-1 (CTF-1) and nuclear factor kappaB (NFkappaB) proteins are required for hormone responsiveness. The p65 subunit of NFkappaB was identified in both nuclear and cytosolic fractions of untreated MCF-7 cells; however, formation of the nuclear NFkappaB complex was E2 independent. Hormonal activation of constructs containing p53 promoter inserts (-106 to -40) and the GAL4-p65 fusion proteins was inhibited by the intracellular Ca2+ ion chelator EGTA-AM and Ca2+/calmodulin-dependent protein kinase (CaMK) inhibitor KN-93. Constitutively active CaMKIV but not CaMKI activated p65, and treatment of MCF-7 cells with E2 induced phosphorylation of CaMKIV but not CaMKI. The results indicate that hormonal activation of p53 though nongenomic pathways was CaMKIV-dependent and involved cooperative p65-CTF-1 interactions.
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Affiliation(s)
- Chunhua Qin
- Department of Veterinary Physiology & Pharmacology, Texas A&M University, College Station, Texas 77843-4466, USA
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23
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Kang HJ, Kim SW, Kim HJ, Ahn SJ, Bae JY, Park SK, Kang D, Hirvonen A, Choe KJ, Noh DY. Polymorphisms in the estrogen receptor-alpha gene and breast cancer risk. Cancer Lett 2002; 178:175-80. [PMID: 11867202 DOI: 10.1016/s0304-3835(01)00861-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The estrogen receptor-alpha (ERalpha) has been known to play a role in the development and progression of breast cancer. Several genetic polymorphisms in the ERalpha gene have been related to breast cancer risk and/or different tumor characteristics. In this study, PCR and direct sequencing based methods were used to examine this issue further in a Korean study population consisting of 155 women, 110 with breast cancer and 45 without cancer. We also assessed the potential role of the ERalpha genotype in ER, PR, p53, c-erbB2, and bcl-2 expression. Only one of the allelic variants of ERalpha gene was found in our study subjects; the (C(975)G) change was present in half of the study subjects. Although this allele had no direct effect in individual breast cancer risk, it was positively associated with tumor PR (P for trend=0.04) and ER expression (P for trend=0.06) and negatively associated with p53 expression (P for trend=0.02).
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Affiliation(s)
- Hee Joon Kang
- Department of Surgery, Seoul National University College of Medicine, 28 Yongon-Dong, Chongno-Gu, Seoul 110-744, South Korea
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24
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Dinda S, Sanchez A, Moudgil V. Estrogen-like effects of thyroid hormone on the regulation of tumor suppressor proteins, p53 and retinoblastoma, in breast cancer cells. Oncogene 2002; 21:761-8. [PMID: 11850804 DOI: 10.1038/sj.onc.1205136] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2001] [Revised: 10/17/2001] [Accepted: 10/31/2001] [Indexed: 12/19/2022]
Abstract
T47D cells represent an estrogen-responsive human ductal carcinoma cell line which expresses detectable levels of estrogen receptor (ER). We have previously shown that estradiol (E(2)) treatment of T47D cells causes an increase in the level of p53 and a concomitant phosphorylation of retinoblastoma protein (pRb). In the present study, we have analysed the expression of p53 and phosphorylation state of pRb and compared the effects of E(2) and triiodothyronine (T(3)) on these phenomena. Cells were grown in a medium containing charcoal-treated serum to deplete the levels of endogenous steroids. Upon confluency, the cells were treated with T(3) (10(-12) to 10(-7) M) for 24 h and the presence of p53 and pRb was detected by Western analysis. E(2) treatment of cells caused a 2-3-fold increase in the level of p53. Presence of T(3) in the medium caused a gradual increase in the level of p53 in a concentration-dependent manner. Under the above conditions, pRb was phosphorylated (detected as an upshift during SDS-PAGE) in the presence of E(2) and T(3). Supplementation of growth medium with T(3) (1 microM) caused an increase in the rate of proliferation of T47D cells and induced hyperphosphorylation of pRb within 4 h; this effect was maintained for up to 12 h. When ICI 164 384 (ICI) (1 microM), an ER antagonist, was combined with E(2) (1 nM) or T(3) (1 microM), effects of hormones on cell proliferation and hyperphosphorylation of pRb were blocked. Western analysis of p53 was supplemented with its cytolocalization by immuno-labeling using laser scanning confocal fluorescence microscopy, which revealed an ICI-sensitive increase in the abundance of p53 in hormone-treated cells. Steroid binding analysis revealed lack of competition by T(3) for the [(3)H]E(2) binding. These results indicate that T(3) regulates T47D cell cycle progression and proliferation raising the p53 level and causing hyperphosphorylation of pRb by a common mechanism involving ER and T(3) receptor (T(3)R)-mediated pathways.
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Affiliation(s)
- Sumi Dinda
- Department of Biological Sciences and Center for Biomedical Research, Oakland University, Rochester, Michigan, MI 48309-4476, USA
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25
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Alban P, Hurd C, Dinda S, Khattree N, Moudgil VK. Differential regulation of retinoblastoma protein by hormonal and antihormonal agents in T47D breast cancer cells. J Steroid Biochem Mol Biol 2001; 77:135-41. [PMID: 11377979 DOI: 10.1016/s0960-0760(01)00043-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Phosphorylation of the tumor suppressor protein, retinoblastoma (pRb), regulates the progression of the cell cycle. Previous work from this laboratory had shown that estradiol (E(2)) regulates tumor suppressor proteins, p53 and retinoblastoma in breast cancer cells. In the present study, we have examined the phosphorylation of pRB in T47D breast cancer cells following treatments with R5020 and antiprogestins. In growth medium containing serum depleted of endogenous steroids by charcoal treatment, pRb appeared mainly in its hypophosphorylated form. Addition of 10 nM R5020 to the culture medium caused hyperphosphorylation of pRb within 24 h, but the hypophosphorylated form of pRb began to accumulate after 72 h. Upon prolonged R5020 treatment (72-96 h), pRb was detected exclusively in its hypophosphorylated form. While treatment of cells with R5020 caused a transient increase in the level of cyclin D1, E(2) addition caused a sustained increase in the level of cyclin D1 consistent with its role in stimulating pRb phosphorylation. Antagonists of both estrogen receptor (ER) and progesterone receptor (PR) blocked the E(2) and R5020-induced pRb phosphorylation, respectively. These results suggest that R5020 induces pRb phosphorylation via a transient increased expression of cyclin D1, whereas E(2) treatment results in sustained expression of cyclin D1 and increased pRb phosphorylation. Furthermore, R5020 effects on pRb phosphorylation appear PR-mediated as no cross-antagonism of pRb phosphorylation was observed: the R5020 effects were blocked by RU486 and ZK98299, but not by the pure ER antagonist, ICI 182, 780 (ICI).
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Affiliation(s)
- P Alban
- Department of Biological Sciences, Center for Biomedical Research, Oakland University, Rochester, MI 48309-4476, USA
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26
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Moudgil VK, Dinda S, Khattree N, Jhanwar S, Alban P, Hurd C. Hormonal regulation of tumor suppressor proteins in breast cancer cells. J Steroid Biochem Mol Biol 2001; 76:105-17. [PMID: 11384868 DOI: 10.1016/s0960-0760(00)00151-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
This laboratory is studying hormonal regulation of tumor suppressor proteins, p53 and retinoblastoma (pRB). Estrogen receptor and progesterone receptor positive human breast cancer cell lines, T47D and MCF-7, were utilized for determining influence of hormonal and antihormonal agents on the level of expression of p53, state of phosphorylation of pRB, and rate of cell proliferation. The expression of p53 in T47D cells grown for 4-5 days in culture medium containing charcoal-treated (stripped) fetal bovine serum declined gradually to 10% of the level seen in control (whole serum, non charcoal-treated) groups. Supplementation of culture medium containing stripped serum with 0.1-1 nM estradiol (E(2)) restored p53 to its level seen in the control within 6-24 h. Under above conditions, treatment of cells with R5020 or RU486 reduced (15-30%) the level of p53. Incubation of cells in E(2)-containing growth medium caused cell proliferation and hyperphosphorylation of pRB; the latter effect was seen maximally between 24-72 h. The E(2)-induced hyperphosphorylation of pRB and increase in the level of p53 were sensitive to the presence of ICI and 4-hydroxy tamoxifen (OHT). T47D and MCF-7 cells were also transiently transfected with a P1CAT reporter plasmid containing c-Myc responsive element and the levels of chloramphenicol acetyltransferase (CAT) activity were observed in response to various treatments. E(2) and OHT caused P1CAT induction as seen by increased CAT activity: E(2) caused an endogenous increase in the expression of an ICI-sensitive c-Myc form. These data suggest that estrogen upregulates p53 expression while progesterone downregulates this process. Further, E(2) regulates p53 level and pRB activity in a coordinated manner.
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Affiliation(s)
- V K Moudgil
- Department of Biological Sciences and the Center for Biomedical Research, Oakland University, Rochester, MI 48309-4476, USA.
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