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Zhang X, Huang L, Sun J, Liu J, Zong Y, Wan L, Yang X, Yan X, Zhang Y, Zhao R, Liu J, Zhong H, Wei C, Yang X, Tai Y, Han Y, Wang Y. Monopolar spindle 1 contributes to tamoxifen resistance in breast cancer through phosphorylation of estrogen receptor α. Breast Cancer Res Treat 2023; 202:595-606. [PMID: 37695401 DOI: 10.1007/s10549-023-07098-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 08/06/2023] [Indexed: 09/12/2023]
Abstract
PURPOSE The overexpression of mitotic kinase monopolar spindle 1 (Mps1) has been identified in many tumor types, and targeting Mps1 for tumor therapy has shown great promise in multiple preclinical cancer models. However, the role played by Mps1 in tamoxifen (TAM) resistance in breast cancer has never been reported. METHODS The sensitivity of breast cancer cells to tamoxifen was analysed in colony formation assays and wound healing assays. Enhanced transactivational activity of estrogen receptor α (ERα) led by Mps1 overexpression was determined by luciferase assays. The interaction between Mps1 and ERα was verified by co-immunoprecipitation and proximity ligation assay. Phosphorylation of ERα by Mps1 was detected by in vitro kinase assay and such phosphorylation process in vivo was proven by co-immunoprecipitation. The potential phosphorylation site(s) of ERα were analyzed by mass spectrometry. RESULTS Mps1 determines the sensitivity of breast cancer cells to tamoxifen treatment. Mps1 overexpression rendered breast cancer cells more resistant to tamoxifen, while an Mps1 inhibitor or siMps1 oligos enabled cancer cells to overcome tamoxifen resistance. Mechanistically, Mps1 interacted with estrogen receptor α and stimulated its transactivational activity in a kinase activity-dependent manner. Mps1 was critical for ERα phosphorylation at Thr224 amino acid site. Importantly, Mps1 failed to enhance the transactivational activity of the ERα-T224A mutant. CONCLUSION Mps1 contributes to tamoxifen resistance in breast cancer and is a potential therapeutic that can overcome tamoxifen resistance in breast cancer.
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Affiliation(s)
- Xuemiao Zhang
- Department of Clinical Laboratory, The Third Medical Center of Chinese PLA General Hospital, The Training Site for Postgraduates of Jinzhou Medical University, Jinzhou, 121001, China
- Beijing Institute of Biotechnology, Beijing, 100071, China
| | - Linfei Huang
- Beijing Institute of Biotechnology, Beijing, 100071, China
| | - Jing Sun
- China-Japan Union Hospital of Jilin University, Changchun, 130000, China
| | - Jialong Liu
- Beijing Institute of Biotechnology, Beijing, 100071, China
| | - Yulong Zong
- Beijing Institute of Biotechnology, Beijing, 100071, China
| | - Luming Wan
- Beijing Institute of Biotechnology, Beijing, 100071, China
| | - Xiaopan Yang
- Beijing Institute of Biotechnology, Beijing, 100071, China
| | - Xue Yan
- Department of Interventional Therapy, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Yanhong Zhang
- Beijing Institute of Biotechnology, Beijing, 100071, China
| | - Ruzhou Zhao
- Beijing Institute of Biotechnology, Beijing, 100071, China
| | - Jing Liu
- Beijing Institute of Biotechnology, Beijing, 100071, China
| | - Hui Zhong
- Beijing Institute of Biotechnology, Beijing, 100071, China
| | - Congwen Wei
- Beijing Institute of Biotechnology, Beijing, 100071, China
| | - Xiaoli Yang
- Department of Clinical Laboratory, The Third Medical Center of Chinese PLA General Hospital, The Training Site for Postgraduates of Jinzhou Medical University, Jinzhou, 121001, China
- Department of Clinical Laboratory, The Third Medical Center of Chinese PLA General Hospital, Beijing, 100039, China
- Clinical School of the Third Medical Center of Chinese PLA General Hospital, Anhui Medical University, Hefei, 230032, China
| | - Yanhong Tai
- Department of Pathology, The Fifth Medical Center of Chinese PLA General Hospital, Beijing, 100166, China
| | - Yue Han
- Department of Interventional Therapy, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021, China
| | - Yanhai Wang
- Department of Clinical Laboratory, Huhhot First Hospital, Huhhot, 010030, China.
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2
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Habara M, Shimada M. Estrogen receptor α revised: Expression, structure, function, and stability. Bioessays 2022; 44:e2200148. [PMID: 36192154 DOI: 10.1002/bies.202200148] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 09/09/2022] [Accepted: 09/09/2022] [Indexed: 11/11/2022]
Abstract
Estrogen receptor α (ERα) is a ligand-dependent transcription factor that regulates the expression of estrogen-responsive genes. Approximately 70% of patients with breast cancer are ERα positive. Estrogen stimulates cancer cell proliferation and contributes to tumor progression. Endocrine therapies, which suppress the ERα signaling pathway, significantly improve the prognosis of patients with breast cancer. However, the development of de novo or acquired endocrine therapy resistance remains a barrier to breast cancer treatment. Therefore, understanding the regulatory mechanisms of ERα is essential to overcome the resistance to treatment. This review focuses on the regulation of ERα expression, including copy number variation, epigenetic regulation, transcriptional regulation, and stability, as well as functions from the point of view post-translational modifications.
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Affiliation(s)
- Makoto Habara
- Department of Veterinary Biochemistry, Yamaguchi University, Yamaguchi, Yamaguchi, Japan
| | - Midori Shimada
- Department of Veterinary Biochemistry, Yamaguchi University, Yamaguchi, Yamaguchi, Japan
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3
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Arao Y, Korach KS. Transactivation Function-1-Mediated Partial Agonist Activity of Selective Estrogen Receptor Modulator Requires Homo-Dimerization of the Estrogen Receptor α Ligand Binding Domain. Int J Mol Sci 2019; 20:ijms20153718. [PMID: 31366023 PMCID: PMC6695978 DOI: 10.3390/ijms20153718] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 07/24/2019] [Accepted: 07/26/2019] [Indexed: 11/16/2022] Open
Abstract
The isolation of estrogen receptor alpha (ERα) cDNA was successful around 30 years ago. The characteristics of ERα protein have been examined from various aspects, primarily through in vitro cell culture studies, but more recently using in vivo experimental models. There remains, however, some uncharacterized ERα functionalities. In particular, the mechanism of partial agonist activity of selective estrogen receptor modulators (SERMs) that involves control of the N-terminal transcription function of ERα, termed AF-1, is still an unsolved ERα functionality. We review the possible mechanism of SERM-dependent regulation of ERα AF-1-mediated transcriptional activity, which includes the role of helix 12 of ERα ligand binding domain (LBD) for SERM-dependent AF-1 regulation. In addition, we describe a specific portion of the LBD that associates with blocking AF-1 activity with an additional role of the F-domain in mediating SERM activity.
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Affiliation(s)
- Yukitomo Arao
- Receptor Biology Section, Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences/NIH, Durham, NC 27709, USA.
| | - Kenneth S Korach
- Receptor Biology Section, Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences/NIH, Durham, NC 27709, USA.
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4
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Gonzalez TL, Rae JM, Colacino JA. Implication of environmental estrogens on breast cancer treatment and progression. Toxicology 2019; 421:41-48. [PMID: 30940549 DOI: 10.1016/j.tox.2019.03.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 03/05/2019] [Accepted: 03/28/2019] [Indexed: 12/22/2022]
Abstract
Breast cancer is the most diagnosed malignancy among women in the United States. Approximately 70% of breast tumors express estrogen receptor alpha and are deemed ER-positive. ER-positive breast tumors depend upon endogenous estrogens to promote ER-mediated cellular proliferation. Decades of research have led to a fundamental understanding of the role ER signaling in this disease and this knowledge has led to significant advancements in the clinical use of antiestrogens for breast cancer treatment. However, adjuvant breast cancer recurrence and metastatic disease progression due to endocrine therapy resistance are prominent and unresolved issues. The established role that estrogens play in breast cancer pathogenesis explains why some patients initially respond to endocrine therapy but also why a significant number of patients become refractory to antiestrogen treatment. It is been hypothesized that exposure to environmental steroid hormone mimics and/or acquired mechanisms of resistance may explain why endocrine therapy fails in a subset of breast cancer patients. This review will highlight: 1) the relationship between ER signaling and breast cancer pathogenesis, 2) the implication of environmental exposures on steroid hormone regulated processes including breast cancer, and 3) the unresolved issue of endocrine therapy resistance.
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Affiliation(s)
- Thomas L Gonzalez
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI, 48109, USA.
| | - James M Rae
- Division of Hematology/ Oncology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, 48109, USA; Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA.
| | - Justin A Colacino
- Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, MI, 48109, USA; Department of Nutritional Sciences, University of Michigan School of Public Health, Ann Arbor, MI, 48109, USA; Center for Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, 48109, USA.
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5
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Katzenellenbogen JA, Mayne CG, Katzenellenbogen BS, Greene GL, Chandarlapaty S. Structural underpinnings of oestrogen receptor mutations in endocrine therapy resistance. Nat Rev Cancer 2018; 18:377-388. [PMID: 29662238 PMCID: PMC6252060 DOI: 10.1038/s41568-018-0001-z] [Citation(s) in RCA: 132] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Oestrogen receptor-α (ERα), a key driver of breast cancer, normally requires oestrogen for activation. Mutations that constitutively activate ERα without the need for hormone binding are frequently found in endocrine-therapy-resistant breast cancer metastases and are associated with poor patient outcomes. The location of these mutations in the ER ligand-binding domain and their impact on receptor conformation suggest that they subvert distinct mechanisms that normally maintain the low basal state of wild-type ERα in the absence of hormone. Such mutations provide opportunities to probe fundamental issues underlying ligand-mediated control of ERα activity. Instructive contrasts between these ERα mutations and those that arise in the androgen receptor (AR) during anti-androgen treatment of prostate cancer highlight differences in how activation functions in ERs and AR control receptor activity, how hormonal pressures (deprivation versus antagonism) drive the selection of phenotypically different mutants, how altered protein conformations can reduce antagonist potency and how altered ligand-receptor contacts can invert the response that a receptor has to an agonist ligand versus an antagonist ligand. A deeper understanding of how ligand regulation of receptor conformation is linked to receptor function offers a conceptual framework for developing new anti-oestrogens that might be more effective in preventing and treating breast cancer.
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Affiliation(s)
| | - Christopher G Mayne
- Beckman Institute for Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Benita S Katzenellenbogen
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Geoffrey L Greene
- The Ben May Department for Cancer Research, University of Chicago, Chicago, IL, USA
| | - Sarat Chandarlapaty
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
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6
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Arao Y, Korach KS. The F domain of estrogen receptor α is involved in species-specific, tamoxifen-mediated transactivation. J Biol Chem 2018; 293:8495-8507. [PMID: 29632071 DOI: 10.1074/jbc.ra117.001212] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 04/06/2018] [Indexed: 11/06/2022] Open
Abstract
Estrogen receptor α (ERα) is a major transducer of estrogen-mediated physiological signals. ERα is a member of the nuclear receptor superfamily, which encompasses ligand-dependent transcription factors. The C terminus of nuclear receptors, termed the F domain, is the least homologous region among the members of this family. The ERα F domain possesses 45 amino acids; however, its function remains unclear. We noticed that the homology of the F domains between mouse and human ERαs is remarkably lower (75.6% similarity) than that between the entire proteins (94.7% similarity). To assess the functionality of the ERα F domains, here we generated chimeric ERα expression constructs with mouse-human-exchanged F domains. Using cell-based in vitro assays, we analyzed the transcriptional coactivator interaction and ligand-binding domain dimerization activities of these mouse-human F domain-swapped ERαs. We found that the transcriptional activity of the mouse WT ERα is more potent than that of the human WT ERα in the human hepatoma cell line HepG2. 4-Hydroxytamoxifen (4OHT)-mediated transcriptional activity of mouse-human F domain-swapped ERαs was the inverse of the WT ERα activities but not estradiol-mediated transcriptional activities. Further experiments with constructs containing deletion or point mutations of a predicted β-strand region within the F domain suggested that this region governs the species-specific 4OHT-mediated transcriptional activity of ERα. We conclude that the ERα F domain has a species-specific function in 4OHT-mediated receptor transactivation and that mouse-human F domain-swapped ERα mutants enable key insights into ERα F domain structure and function.
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Affiliation(s)
- Yukitomo Arao
- From the Receptor Biology Section, Reproductive and Developmental Biology Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709
| | - Kenneth S Korach
- From the Receptor Biology Section, Reproductive and Developmental Biology Laboratory, NIEHS, National Institutes of Health, Research Triangle Park, North Carolina 27709
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7
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Arnal JF, Lenfant F, Metivier R, Flouriot G, Henrion D, Adlanmerini M, Fontaine C, Gourdy P, Chambon P, Katzenellenbogen B, Katzenellenbogen J. Membrane and Nuclear Estrogen Receptor Alpha Actions: From Tissue Specificity to Medical Implications. Physiol Rev 2017; 97:1045-1087. [DOI: 10.1152/physrev.00024.2016] [Citation(s) in RCA: 213] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 12/19/2016] [Accepted: 01/18/2017] [Indexed: 12/22/2022] Open
Abstract
Estrogen receptor alpha (ERα) has been recognized now for several decades as playing a key role in reproduction and exerting functions in numerous nonreproductive tissues. In this review, we attempt to summarize the in vitro studies that are the basis of our current understanding of the mechanisms of action of ERα as a nuclear receptor and the key roles played by its two activation functions (AFs) in its transcriptional activities. We then depict the consequences of the selective inactivation of these AFs in mouse models, focusing on the prominent roles played by ERα in the reproductive tract and in the vascular system. Evidence has accumulated over the two last decades that ERα is also associated with the plasma membrane and activates non-nuclear signaling from this site. These rapid/nongenomic/membrane-initiated steroid signals (MISS) have been characterized in a variety of cell lines, and in particular in endothelial cells. The development of selective pharmacological tools that specifically activate MISS and the generation of mice expressing an ERα protein impeded for membrane localization have begun to unravel the physiological role of MISS in vivo. Finally, we discuss novel perspectives for the design of tissue-selective ER modulators based on the integration of the physiological and pathophysiological roles of MISS actions of estrogens.
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Affiliation(s)
- Jean-Francois Arnal
- I2MC, Institut National de la Santé et de la Recherche Médicale (INSERM) U 1048, Université de Toulouse 3 and CHU de Toulouse, Toulouse, France; Equipe SP@RTE UMR 6290 CNRS, Institut de Genétique et Développement de Rennes, Université de Rennes 1, Campus de Beaulieu, Rennes, France; Université de Rennes 1, Institut de Recherche en Santé, Environnement et Travail (Irest–INSERM UMR 1085), Equipe TREC, Rennes, France; Unité Mixte de Recherche 6214, Centre National de la Recherche Scientifique, Angers,
| | - Françoise Lenfant
- I2MC, Institut National de la Santé et de la Recherche Médicale (INSERM) U 1048, Université de Toulouse 3 and CHU de Toulouse, Toulouse, France; Equipe SP@RTE UMR 6290 CNRS, Institut de Genétique et Développement de Rennes, Université de Rennes 1, Campus de Beaulieu, Rennes, France; Université de Rennes 1, Institut de Recherche en Santé, Environnement et Travail (Irest–INSERM UMR 1085), Equipe TREC, Rennes, France; Unité Mixte de Recherche 6214, Centre National de la Recherche Scientifique, Angers,
| | - Raphaël Metivier
- I2MC, Institut National de la Santé et de la Recherche Médicale (INSERM) U 1048, Université de Toulouse 3 and CHU de Toulouse, Toulouse, France; Equipe SP@RTE UMR 6290 CNRS, Institut de Genétique et Développement de Rennes, Université de Rennes 1, Campus de Beaulieu, Rennes, France; Université de Rennes 1, Institut de Recherche en Santé, Environnement et Travail (Irest–INSERM UMR 1085), Equipe TREC, Rennes, France; Unité Mixte de Recherche 6214, Centre National de la Recherche Scientifique, Angers,
| | - Gilles Flouriot
- I2MC, Institut National de la Santé et de la Recherche Médicale (INSERM) U 1048, Université de Toulouse 3 and CHU de Toulouse, Toulouse, France; Equipe SP@RTE UMR 6290 CNRS, Institut de Genétique et Développement de Rennes, Université de Rennes 1, Campus de Beaulieu, Rennes, France; Université de Rennes 1, Institut de Recherche en Santé, Environnement et Travail (Irest–INSERM UMR 1085), Equipe TREC, Rennes, France; Unité Mixte de Recherche 6214, Centre National de la Recherche Scientifique, Angers,
| | - Daniel Henrion
- I2MC, Institut National de la Santé et de la Recherche Médicale (INSERM) U 1048, Université de Toulouse 3 and CHU de Toulouse, Toulouse, France; Equipe SP@RTE UMR 6290 CNRS, Institut de Genétique et Développement de Rennes, Université de Rennes 1, Campus de Beaulieu, Rennes, France; Université de Rennes 1, Institut de Recherche en Santé, Environnement et Travail (Irest–INSERM UMR 1085), Equipe TREC, Rennes, France; Unité Mixte de Recherche 6214, Centre National de la Recherche Scientifique, Angers,
| | - Marine Adlanmerini
- I2MC, Institut National de la Santé et de la Recherche Médicale (INSERM) U 1048, Université de Toulouse 3 and CHU de Toulouse, Toulouse, France; Equipe SP@RTE UMR 6290 CNRS, Institut de Genétique et Développement de Rennes, Université de Rennes 1, Campus de Beaulieu, Rennes, France; Université de Rennes 1, Institut de Recherche en Santé, Environnement et Travail (Irest–INSERM UMR 1085), Equipe TREC, Rennes, France; Unité Mixte de Recherche 6214, Centre National de la Recherche Scientifique, Angers,
| | - Coralie Fontaine
- I2MC, Institut National de la Santé et de la Recherche Médicale (INSERM) U 1048, Université de Toulouse 3 and CHU de Toulouse, Toulouse, France; Equipe SP@RTE UMR 6290 CNRS, Institut de Genétique et Développement de Rennes, Université de Rennes 1, Campus de Beaulieu, Rennes, France; Université de Rennes 1, Institut de Recherche en Santé, Environnement et Travail (Irest–INSERM UMR 1085), Equipe TREC, Rennes, France; Unité Mixte de Recherche 6214, Centre National de la Recherche Scientifique, Angers,
| | - Pierre Gourdy
- I2MC, Institut National de la Santé et de la Recherche Médicale (INSERM) U 1048, Université de Toulouse 3 and CHU de Toulouse, Toulouse, France; Equipe SP@RTE UMR 6290 CNRS, Institut de Genétique et Développement de Rennes, Université de Rennes 1, Campus de Beaulieu, Rennes, France; Université de Rennes 1, Institut de Recherche en Santé, Environnement et Travail (Irest–INSERM UMR 1085), Equipe TREC, Rennes, France; Unité Mixte de Recherche 6214, Centre National de la Recherche Scientifique, Angers,
| | - Pierre Chambon
- I2MC, Institut National de la Santé et de la Recherche Médicale (INSERM) U 1048, Université de Toulouse 3 and CHU de Toulouse, Toulouse, France; Equipe SP@RTE UMR 6290 CNRS, Institut de Genétique et Développement de Rennes, Université de Rennes 1, Campus de Beaulieu, Rennes, France; Université de Rennes 1, Institut de Recherche en Santé, Environnement et Travail (Irest–INSERM UMR 1085), Equipe TREC, Rennes, France; Unité Mixte de Recherche 6214, Centre National de la Recherche Scientifique, Angers,
| | - Benita Katzenellenbogen
- I2MC, Institut National de la Santé et de la Recherche Médicale (INSERM) U 1048, Université de Toulouse 3 and CHU de Toulouse, Toulouse, France; Equipe SP@RTE UMR 6290 CNRS, Institut de Genétique et Développement de Rennes, Université de Rennes 1, Campus de Beaulieu, Rennes, France; Université de Rennes 1, Institut de Recherche en Santé, Environnement et Travail (Irest–INSERM UMR 1085), Equipe TREC, Rennes, France; Unité Mixte de Recherche 6214, Centre National de la Recherche Scientifique, Angers,
| | - John Katzenellenbogen
- I2MC, Institut National de la Santé et de la Recherche Médicale (INSERM) U 1048, Université de Toulouse 3 and CHU de Toulouse, Toulouse, France; Equipe SP@RTE UMR 6290 CNRS, Institut de Genétique et Développement de Rennes, Université de Rennes 1, Campus de Beaulieu, Rennes, France; Université de Rennes 1, Institut de Recherche en Santé, Environnement et Travail (Irest–INSERM UMR 1085), Equipe TREC, Rennes, France; Unité Mixte de Recherche 6214, Centre National de la Recherche Scientifique, Angers,
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8
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Yaşar P, Ayaz G, User SD, Güpür G, Muyan M. Molecular mechanism of estrogen-estrogen receptor signaling. Reprod Med Biol 2016; 16:4-20. [PMID: 29259445 PMCID: PMC5715874 DOI: 10.1002/rmb2.12006] [Citation(s) in RCA: 262] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 05/16/2016] [Indexed: 02/06/2023] Open
Abstract
17β‐Estradiol (E2), as the main circulating estrogen hormone, regulates many tissue and organ functions in physiology. The effects of E2 on cells are mediated by the transcription factors and estrogen receptor (ER)α and ERβ that are encoded by distinct genes. Localized at the peri‐membrane, mitochondria, and the nucleus of cells that are dependent on estrogen target tissues, the ERs share similar, as well as distinct, regulatory potentials. Different intracellular localizations of the ERs result in dynamically integrated and finely tuned E2 signaling cascades that orchestrate cellular growth, differentiation, and death. The deregulation of E2–ER signaling plays a critical role in the initiation and progression of target tissue malignancies. A better understanding of the complex regulatory mechanisms that underlie ER actions in response to E2 therefore holds a critical trajectory for the development of novel prognostic and therapeutic approaches with substantial impacts on the systemic management of target tissue diseases.
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Affiliation(s)
- Pelin Yaşar
- Department of Biological Sciences Middle East Technical University Ankara Turkey
| | - Gamze Ayaz
- Department of Biological Sciences Middle East Technical University Ankara Turkey
| | - Sırma Damla User
- Department of Biological Sciences Middle East Technical University Ankara Turkey
| | - Gizem Güpür
- Department of Biological Sciences Middle East Technical University Ankara Turkey.,Present address: Cell and Molecular Biology Program Duke University Durham North Carolina USA
| | - Mesut Muyan
- Department of Biological Sciences Middle East Technical University Ankara Turkey
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9
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Patel SR, Skafar DF. Modulation of nuclear receptor activity by the F domain. Mol Cell Endocrinol 2015; 418 Pt 3:298-305. [PMID: 26184856 DOI: 10.1016/j.mce.2015.07.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Revised: 07/09/2015] [Accepted: 07/09/2015] [Indexed: 10/23/2022]
Abstract
The F domain located at the C-terminus of proteins is one of the least conserved regions of the estrogen receptors alpha and beta, members of the nuclear hormone receptor superfamily. Indeed, many members of the superfamily lack the F domain. However, when present, removing the F domain entirely or mutating it alters transactivation, dimerization, and the responses to agonist and antagonist ligands. This review focuses on the functions of the F domain of the estrogen receptors, particularly in relation to other members of the superfamily.
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Affiliation(s)
- Shivali R Patel
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Debra F Skafar
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI, USA.
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10
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Fan P, Maximov PY, Curpan RF, Abderrahman B, Jordan VC. The molecular, cellular and clinical consequences of targeting the estrogen receptor following estrogen deprivation therapy. Mol Cell Endocrinol 2015; 418 Pt 3:245-63. [PMID: 26052034 PMCID: PMC4760743 DOI: 10.1016/j.mce.2015.06.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 05/20/2015] [Accepted: 06/01/2015] [Indexed: 01/04/2023]
Abstract
During the past 20 years our understanding of the control of breast tumor development, growth and survival has changed dramatically. The once long forgotten application of high dose synthetic estrogen therapy as the first chemical therapy to treat any cancer has been resurrected, refined and reinvented as the new biology of estrogen-induced apoptosis. High dose estrogen therapy was cast aside once tamoxifen, from its origins as a failed "morning after pill", was reinvented as the first targeted therapy to treat any cancer. The current understanding of the mechanism of estrogen-induced apoptosis is described as a consequence of acquired resistance to long term antihormone therapy in estrogen receptor (ER) positive breast cancer. The ER signal transduction pathway remains a target for therapy in breast cancer despite "antiestrogen" resistance, but becomes a regulator of resistance. Multiple mechanisms of resistance come into play: Selective ER modulator (SERM) stimulated growth, growth factor/ER crosstalk, estrogen-induced apoptosis and mutations of ER. But it is with the science of estrogen-induced apoptosis that the next innovation in women's health will be developed. Recent evidence suggests that the glucocorticoid properties of medroxyprogesterone acetate blunt estrogen-induced apoptosis in estrogen deprived breast cancer cell populations. As a result breast cancer develops during long-term hormone replacement therapy (HRT). A new synthetic progestin with estrogen-like properties, such as the 19 nortestosterone derivatives used in oral contraceptives, will continue to protect the uterus from unopposed estrogen stimulation but at the same time, reinforce apoptosis in vulnerable populations of nascent breast cancer cells.
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Affiliation(s)
- Ping Fan
- Department of Breast Medical Oncology, MD Anderson Cancer Center, Houston, TX, USA
| | - Philipp Y Maximov
- Department of Breast Medical Oncology, MD Anderson Cancer Center, Houston, TX, USA
| | - Ramona F Curpan
- Institute of Chemistry, Romanian Academy, Timisoara, Romania
| | | | - V Craig Jordan
- Department of Breast Medical Oncology, MD Anderson Cancer Center, Houston, TX, USA.
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11
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Jordan VC, Curpan R, Maximov PY. Estrogen receptor mutations found in breast cancer metastases integrated with the molecular pharmacology of selective ER modulators. J Natl Cancer Inst 2015; 107:djv075. [PMID: 25838462 DOI: 10.1093/jnci/djv075] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2014] [Accepted: 02/24/2015] [Indexed: 01/11/2023] Open
Abstract
The consistent reports of mutations at Asp538 and Tyr537 in helix 12 of the ligand-binding domain (LBD) of estrogen receptors (ERs) from antihormone-resistant breast cancer metastases constitute an important advance. The mutant amino acids interact with an anchor amino acid, Asp351, to close the LBD, thereby creating a ligand-free constitutively activated ER. Amino acids Asp 538, Tyr 537, and Asp 351 are known to play a role in either the turnover of ER, the antiestrogenic activity of the ER complex, or the estrogen-like actions of selective ER modulators. A unifying mechanism of action for these amino acids to enhance ER gene activation and growth response is presented. There is a range of mutations described in metastases vs low to zero in primary disease, so the new knowledge is of clinical relevance, thereby confirming an additional mechanism of acquired resistance to antihormone therapy through cell population selection pressure and enrichment during treatment. Circulating tumor cells containing ER mutations can be cultured ex vivo, and tumor tissues can be grown as patient-derived xenografts to add a new dimension for testing drug susceptibility for future drug discovery.
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Affiliation(s)
- V Craig Jordan
- MD Anderson Cancer Center, Department of Breast Medical Oncology, Houston, TX (VCJ, PYM); Institute of Chemistry, Romanian Academy, Timisoara, Romania (RC).
| | - Ramona Curpan
- MD Anderson Cancer Center, Department of Breast Medical Oncology, Houston, TX (VCJ, PYM); Institute of Chemistry, Romanian Academy, Timisoara, Romania (RC)
| | - Philipp Y Maximov
- MD Anderson Cancer Center, Department of Breast Medical Oncology, Houston, TX (VCJ, PYM); Institute of Chemistry, Romanian Academy, Timisoara, Romania (RC)
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12
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Pawlak M, Lefebvre P, Staels B. General molecular biology and architecture of nuclear receptors. Curr Top Med Chem 2012; 12:486-504. [PMID: 22242852 PMCID: PMC3637177 DOI: 10.2174/156802612799436641] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Accepted: 11/22/2011] [Indexed: 12/12/2022]
Abstract
Nuclear receptors (NRs) regulate and coordinate multiple processes by integrating internal and external signals, thereby maintaining homeostasis in front of nutritional, behavioral and environmental challenges. NRs exhibit strong similarities in their structure and mode of action: by selective transcriptional activation or repression of cognate target genes, which can either be controlled through a direct, DNA binding-dependent mechanism or through crosstalk with other transcriptional regulators, NRs modulate the expression of gene clusters thus achieving coordinated tissue responses. Additionally, non genomic effects of NR ligands appear mediated by ill-defined mechanisms at the plasma membrane. These effects mediate potential therapeutic effects as small lipophilic molecule targets, and many efforts have been put in elucidating their precise mechanism of action and pathophysiological roles. Currently, numerous nuclear receptor ligand analogs are used in therapy or are tested in clinical trials against various diseases such as hypertriglyceridemia, atherosclerosis, diabetes, allergies and cancer and others.
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Affiliation(s)
- Michal Pawlak
- Récepteurs nucléaires, maladies cardiovasculaires et diabète
INSERM : U1011Institut Pasteur de LilleUniversité Lille II - Droit et santé1 rue du Prof Calmette 59019 Lille Cedex,FR
| | - Philippe Lefebvre
- Récepteurs nucléaires, maladies cardiovasculaires et diabète
INSERM : U1011Institut Pasteur de LilleUniversité Lille II - Droit et santé1 rue du Prof Calmette 59019 Lille Cedex,FR
| | - Bart Staels
- Récepteurs nucléaires, maladies cardiovasculaires et diabète
INSERM : U1011Institut Pasteur de LilleUniversité Lille II - Droit et santé1 rue du Prof Calmette 59019 Lille Cedex,FR
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13
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Williams CC, Basu A, El-Gharbawy A, Carrier LM, Smith CL, Rowan BG. Identification of four novel phosphorylation sites in estrogen receptor alpha: impact on receptor-dependent gene expression and phosphorylation by protein kinase CK2. BMC BIOCHEMISTRY 2009; 10:36. [PMID: 20043841 PMCID: PMC2811108 DOI: 10.1186/1471-2091-10-36] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2009] [Accepted: 12/31/2009] [Indexed: 12/13/2022]
Abstract
Background Estrogen receptor α (ERα) phosphorylation is important for estrogen-dependent transcription of ER-dependent genes, ligand-independent receptor activation and endocrine therapy response in breast cancer. However ERα phosphorylation at the previously identified sites does not fully account for these receptor functions. To determine if additional ERα phosphorylation sites exist, COS-1 cells expressing human ERα were labeled with [32P]H3PO4 in vivo and ERα tryptic phosphopeptides were isolated to identify phosphorylation sites. Results Previously uncharacterized phosphorylation sites at serines 46/47, 282, 294, and 559 were identified by manual Edman degradation and phosphoamino acid analysis and confirmed by mutagenesis and phospho-specific antibodies. Antibodies detected phosphorylation of endogenous ERα in MCF-7, MCF-7-LCC2, and Ishikawa cancer cell lines by immunoblot. Mutation of Ser-282 and Ser-559 to alanine (S282A, S559A) resulted in ligand independent activation of ERα as determined by both ERE-driven reporter gene assays and endogenous pS2 gene expression in transiently transfected HeLa cells. Mutation of Ser-46/47 or Ser-294 to alanine markedly reduced estradiol dependent reporter activation. Additionally protein kinase CK2 was identified as a kinase that phosphorylated ERα at S282 and S559 using motif analysis, in vitro kinase assays, and incubation of cells with CK2 kinase inhibitor. Conclusion These novel ERα phosphorylation sites represent new means for modulation of ERα activity. S559 represents the first phosphorylation site identified in the extreme C-terminus (F domain) of a steroid receptor.
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Affiliation(s)
- Christopher C Williams
- 1Division of Basic Pharmaceutical Sciences, College of Pharmacy, Xavier University of Louisiana, New Orleans, LA, USA.
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14
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Raingeard D, Cancio I, Cajaraville MP. Cloning and expression pattern of peroxisome proliferator-activated receptors, estrogen receptor alpha and retinoid X receptor alpha in the thicklip grey mullet Chelon labrosus. Comp Biochem Physiol C Toxicol Pharmacol 2009; 149:26-35. [PMID: 18619562 DOI: 10.1016/j.cbpc.2008.06.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2008] [Revised: 06/17/2008] [Accepted: 06/17/2008] [Indexed: 02/07/2023]
Abstract
Aquatic organisms are exposed to diverse xenobiotics that cause peroxisome proliferation and/or endocrine disruption, both modulated in vertebrates by transcription factors of the nuclear receptor (NR) superfamily. Peroxisome proliferators are agonists of peroxisome proliferator-activated receptors (PPARs) that heterodimerize with the retinoid X receptor (RXR). Many xenoestrogens activate the estrogen receptor (ER). Here, 1090 bp of PPARalpha, 1255 bp of PPARgamma, 278 bp of RXRalpha, and 578 bp of ERalpha of thicklip grey mullet Chelon labrosus were cloned. Sequences were highly conserved, although relevant changes with respect to mammalian homologs were identified in PPARgamma and ERalpha. Semi-quantitative RT-PCR was used to determine if these NRs were expressed in different tissues of male, female and undifferentiated mullets captured in January and June. Expression of PPARs was highest in liver and lowest in muscle. RXRalpha expression was homogeneous excepting a low expression in male and female gill in January and brain and heart of undifferentiated fish in January and June. ERalpha expression predominated in liver and female gonad in June. The expression level of PPARs and ERalpha was significantly higher in liver in January than in gills in January or June. The present results show tissue-dependent modulation of expression of NRs in mullets.
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Affiliation(s)
- Damien Raingeard
- Laboratory of Cell Biology and Histology, Department of Zoology and Animal Cell Biology, University of the Basque Country, Bilbao, Basque Country, Spain
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15
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Yang J, Singleton DW, Shaughnessy EA, Khan SA. The F-domain of estrogen receptor-alpha inhibits ligand induced receptor dimerization. Mol Cell Endocrinol 2008; 295:94-100. [PMID: 18762230 DOI: 10.1016/j.mce.2008.08.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2008] [Revised: 07/02/2008] [Accepted: 08/03/2008] [Indexed: 11/26/2022]
Abstract
The role of the carboxyl terminal F-domain of estrogen receptor (ERalpha) is uncertain, but evidence suggests that this region may impart internal restraint on ER dimerization in the presence of 17beta-estradiol (E2). To identify the C-terminal residues affecting human ERalpha activation, we created a series of deletions and examined E2 induced receptor dimerization and transactivation. Deletion of the final 24 C-terminal amino acids of the F-domain (Delta7b) yielded a fivefold increase in dimerization, when compared to wild type (wt) ERalpha in the presence of 2nM E2, utilizing a yeast two-hybrid assay. This increase in dimerization is similar to that observed when the entire F-domain was deleted. Measurement of mutant:mutant homodimer formation yielded similar increases compared to mutant:wt interactions. Interestingly, a point mutation at the C-terminus (mut 3) showed increases in dimerization comparable to that of Delta7b in the presence of nanomolar amounts of E2. However, at sub-nanomolar levels of E2, mut 3 behaved similarly to wt ERalpha, whereas Delta7b maintained striking increases in dimerization. Determination of E2 binding affinity (Kd) constants revealed only marginal differences for wt and F-domain mutants, suggesting that the F-domain affects dimerization directly. We also observed enhanced interaction of F domain mutants with p160 family coactivator SRC1. Finally, transcriptional regulation of estrogen responsive reporters, 2XERE-LacZ and 3XERE-Luc in yeast and mammalian cells, respectively, reflected the increased propensity for dimerization by F domain mutants. Together, these data indicate that the C-terminal amino acids of ERalpha are critical for attenuation of E2 induced receptor dimerization and transcriptional activity.
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Affiliation(s)
- Jun Yang
- Department of Cancer and Cell Biology, University of Cincinnati College of Medicine, Cincinnati, OH, United States
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16
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Zilli M, Grassadonia A, Tinari N, Di Giacobbe A, Gildetti S, Giampietro J, Natoli C, Iacobelli S. Molecular mechanisms of endocrine resistance and their implication in the therapy of breast cancer. Biochim Biophys Acta Rev Cancer 2008; 1795:62-81. [PMID: 18804516 DOI: 10.1016/j.bbcan.2008.08.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2008] [Revised: 08/11/2008] [Accepted: 08/14/2008] [Indexed: 01/04/2023]
Abstract
The use of endocrine agents is a safe and effective treatment in the management of hormone-sensitive breast cancer. Unfortunately, sooner or later, tumor cells develop resistance to endocrine manipulation making useless this approach. During the last decade, new molecules and intracellular signaling pathways involved in endocrine resistance have been identified. Several studies have documented that estrogen receptor signaling may maintain a pivotal role in the tumor growth despite the failure of a previous hormonal treatment. In this review we will discuss the general principles for optimizing the choice of endocrine therapy based on an understanding of the molecular mechanisms responsible for resistance to the different anti-hormonal agents.
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Affiliation(s)
- Marinella Zilli
- Department of Oncology and Neurosciences, University G D'Annunzio Medical School, Via dei Vestini, Chieti, Italy
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17
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Skafar DF, Zhao C. The multifunctional estrogen receptor-alpha F domain. Endocrine 2008; 33:1-8. [PMID: 18363044 DOI: 10.1007/s12020-008-9054-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2007] [Revised: 02/04/2008] [Accepted: 03/04/2008] [Indexed: 10/22/2022]
Abstract
The members of the nuclear receptor superfamily act as transcriptional regulatory factors and exhibit a multidomain structure characterized as domains A-E/F. This review focuses on a small, relatively understudied region at the extreme carboxy-terminus of the estrogen receptor (ER) alpha, the F domain. The F domain contributes to differences in the activity of ER alpha and beta subtypes; it is required for tamoxifen's agonist activity on an estrogen response element, and it modifies the receptor's interactions with coregulators including steroid receptor coactivator-1. The differences between the F domains of the ER alpha and beta subtypes and among the other members of the nuclear hormone receptor superfamily may offer opportunities for selective control of the activity of these proteins.
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Affiliation(s)
- Debra F Skafar
- Department of Physiology, Wayne State University School of Medicine, 540 E. Canfield, Detroit, MI, 48201, USA.
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18
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Takayama S, Hostick U, Haendel M, Eisen J, Darimont B. An F-domain introduced by alternative splicing regulates activity of the zebrafish thyroid hormone receptor alpha. Gen Comp Endocrinol 2008; 155:176-89. [PMID: 17583703 PMCID: PMC3758257 DOI: 10.1016/j.ygcen.2007.04.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2006] [Revised: 03/19/2007] [Accepted: 04/13/2007] [Indexed: 11/15/2022]
Abstract
Thyroid hormones (THs) play an important role in vertebrate development; however, the underlying mechanisms of their actions are still poorly understood. Zebrafish (Danio rerio) is an emerging vertebrate model system to study the roles of THs during development. In general, the response to THs relies on closely related proteins and mechanisms across vertebrate species, however some species-specific differences exist. In contrast to mammals, zebrafish has two TRalpha genes (thraa, thrab). Moreover, the zebrafish thraa gene expresses a TRalpha isoform (TRalphaA1) that differs from other TRs by containing additional C-terminal amino acids. C-terminal extensions, called "F domains", are common in other members of the nuclear receptor superfamily and modulate the response of these receptors to hormones. Here we demonstrate that the F-domain constrains the transcriptional activity of zebrafish TRalpha by altering the selectivity of this receptor for certain coactivator binding motifs. We found that the F-domain of zebrafish TRalphaA1 is encoded on a separate exon whose inclusion is regulated by alternative splicing, indicating a regulatory role of the F-domain in vivo. Quantitative expression analyses revealed that TRalphaA1 is primarily expressed in reproductive organs whereas TRalphaB and the TRalphaA isoform that lacks the F-domain (TRalphaA1-2) appear to be ubiquitous. The relative expression levels of these TRalpha transcripts differ in a tissue-specific manner suggesting that zebrafish uses both alternative splicing and differential expression of TRalpha genes to diversify the cellular response to THs.
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Affiliation(s)
- Sachiko Takayama
- Institutes of Molecular Biology, University of Oregon, Eugene, OR, 97403-1229, USA
| | - Ute Hostick
- Institutes of Molecular Biology, University of Oregon, Eugene, OR, 97403-1229, USA
- Neuroscience, University of Oregon, Eugene, OR, 97403-1229, USA
| | - Melissa Haendel
- Neuroscience, University of Oregon, Eugene, OR, 97403-1229, USA
| | - Judith Eisen
- Neuroscience, University of Oregon, Eugene, OR, 97403-1229, USA
| | - Beatrice Darimont
- Institutes of Molecular Biology, University of Oregon, Eugene, OR, 97403-1229, USA
- Corresponding author: Institute of Molecular Biology University of Oregon Eugene, OR, 97403-1229 Phone: (541) 346-5265 Fax: (541) 346-5891
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19
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Wu F, Safe S. Differential activation of wild-type estrogen receptor alpha and C-terminal deletion mutants by estrogens, antiestrogens and xenoestrogens in breast cancer cells. J Steroid Biochem Mol Biol 2007; 103:1-9. [PMID: 17141713 DOI: 10.1016/j.jsbmb.2006.07.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2006] [Accepted: 07/06/2006] [Indexed: 12/21/2022]
Abstract
17beta-Estradiol (E2), diethylstilbestrol (DES) and several synthetic (or xenoestrogenic) compounds induced transactivation in MCF-7 or MDA-MB-231 cells transfected with wild-type estrogen receptor alpha (ERalpha) and a construct (pERE(3)) containing three tandem estrogen responsive elements (EREs) linked to a luciferase gene. In contrast, the antiestrogens ICI 182,780 and 4-hydroxytamoxifen (4-OHT) were inactive in this assay. We have investigated the effects of these compounds and several structurally-diverse estrogenic compounds on transactivation in cells transfected with pERE(3) and wild-type ERalpha, mutant ERalpha (1-553), and ERalpha (1-537) containing deletions of amino acids 595-554 and 595-538, respectively. These constructs were used to develop an in vitro assay to distinguish between different structural classes of estrogenic compounds. The results obtained using these constructs were highly cell context- and structure-dependent. Neither E2- nor diethylstilbestrol-induced transactivation in MCF-7 (or MDA-MB-231) cells transfected with pERE(3)/ERalpha (1-537) due to partial deletion of helix 12; however, octylphenol and nonlylphenol, resveratrol (a phytoestrogen), kepone and 2',3',4',5'-tetrachloro-4-biphenylol were "estrogenic" in MCF-7 cells transfected with pERE(3)/ERalpha (1-537). Moreover, the structure-dependent estrogenic activities of several synthetic estrogens (xenoestrogens) in MDA-MB-231 cells were different than those observed in MCF-7 cells. These results demonstrate that the estrogenic activity of many synthetic compounds do not require activation function 2 (AF-2) of ERalpha and are mechanistically different from E2. These data suggest that xenoestrogens are selective ER modulators (SERMs).
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Affiliation(s)
- Fei Wu
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, United States
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20
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Koide A, Zhao C, Naganuma M, Abrams J, Deighton-Collins S, Skafar DF, Koide S. Identification of regions within the F domain of the human estrogen receptor alpha that are important for modulating transactivation and protein-protein interactions. Mol Endocrinol 2006; 21:829-42. [PMID: 17185393 DOI: 10.1210/me.2006-0203] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The estrogen receptor (ER)alpha is a biologically and clinically important ligand-modulated transcription factor. The F domain of the ERalpha modulates its functions in a ligand-, promoter-, and cell-specific manner. To identify the region(s) responsible for these functions, we characterized the effects of serial truncations within the F domain. We found that truncating the last 16 residues of the F domain altered the activity of the human ERalpha (hERalpha) on an estrogen response element-driven promoter in response to estradiol or 4-hydroxytamoxifen (4-OHT), its sensitivity to overexpression of the coactivator steroid receptor coactivator-1 in mammalian cells, and its interaction with a receptor-interacting domain of the coactivator steroid receptor coactivator-1 or engineered proteins ("monobodies") that specifically bind to ERalpha/ligand complexes in a yeast two-hybrid system. Most importantly, the ability of the ER to induce pS2 was reduced in MDA-MB-231 cells stably expressing this truncated ER vs. the wild-type ER. The region includes a distinctive segment (residues 579-584; LQKYYIT) having a high content of bulky and/or hydrophobic amino acids that was previously predicted to adopt a beta-strand-like structure. As previously reported, removal of the entire F domain was necessary to eliminate the agonist activity of 4-OHT. In addition, mutation of the vicinal glycine residues between the ligand-binding domain and F domains specifically reduced the 4-OHT-dependent interactions of the hERalpha ligand-binding domain and F domains with monobodies. These results show that regions within the F domain of the hERalpha selectively modulate its activity and its interactions with other proteins.
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Affiliation(s)
- Akiko Koide
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois 60637, USA
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21
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Abstract
The estrogen receptor-alpha is a wonderfully complex protein important in normal biology, breast cancer, and as a target for anti-cancer agents. We are using the available structures of the hERalpha as well as secondary structure predictions to guide site-directed mutagenesis in order to test the importance of specific interactions and regions in the ligand-regulated activity of the protein. In one area of interest, we are investigating the role of the F domain in the ligand-stimulated activity of the hERalpha. Results from our laboratory and others suggest that the F domain modulates the activity of the hERalpha. In order to better understand the role of the F domain in the hERalpha, we have constructed mutants within this region. Mutations within a predicted alpha-helical region alter the response of the ER to estradiol (E2), eliminate or impair the agonist activity of 4-hydroxytamoxifen (4-OHT), and alter the ability of E2 to overcome 4-OHT's antagonist activity. Deleting the F domain increases the affinity of the receptor for E2; by contrast, mutating a residue in the middle of the predicted helix to a proline does not alter the affinity for E2, but does change the binding mechanism from a positive cooperative to a noncooperative interaction. These and other results show the F domain exhibits substantial functional complexity, and support the idea that this domain modulates the activity of the hERalpha. In a second area of interest, we are investigating the role of hydrophobic and hydrogen-bonding interactions at the start of helix 12 in the activity of the hERalpha. Leucine-536 (L536) has been proposed to participate in hydrophobic interactions that form part of a capping motif stabilizing the start of helix 12. When mutated, the resulting receptors exhibit a reduced response, or even an inverted response, to E2 and 4-OHT on both ERE-driven and AP-1-driven promoters. Interestingly, these mutated receptors also exhibit altered interactions with probes that recognize the agonist-bound and 4-OHT-bound conformations of the ERalpha. Thus, L536 couples the binding of ligand with the conformation of the receptor. Overall, these results show that combining structure-based hypotheses with functional tests of the ER's activity can identify regions and interactions that are important in the ligand-stimulated activity of the protein.
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Affiliation(s)
- Debra F Skafar
- Department of Physiology, Wayne State University School of Medicine, 540 E. Canfield, Detroit, MI 48201, USA.
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22
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Zhao C, Abrams J, Skafar DF. Targeted mutation of key residues at the start of helix 12 in the hERalpha ligand-binding domain identifies the role of hydrogen-bonding and hydrophobic interactions in the activity of the protein. J Steroid Biochem Mol Biol 2006; 98:1-11. [PMID: 16191480 DOI: 10.1016/j.jsbmb.2005.06.036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2005] [Accepted: 06/30/2005] [Indexed: 11/21/2022]
Abstract
Estradiol (E(2)) and tamoxifen exert their effects through two members of the nuclear receptor superfamily, estrogen receptor (ER)-alpha and -beta. We want to identify the key interactions linking ligand-binding and activity of the ERalpha. Asp-351 and Leu-536 participate in hydrogen bond (Asp-351) and hydrophobic (Leu-536) interactions at the start of helix 12 in the ligand-binding domain (LBD) of the ERalpha. Mutations at each position alter ER activity, but we do not know which is more important. We mutated these residues in combination and individually and assessed the activity of the mutated ERs in the absence and presence of E(2) and 4-OHT on an ERE-driven and an AP-1-driven promoter, as well as their ability to interact with coregulators. On an ERE-driven promoter, the residue at position 351 determined whether E(2) stimulated or reduced the activity of the ER, as well as the level of activity in the presence of 4-OHT. Surprisingly, mutation of both residues generally did not produce cumulative deleterious effects, and they exerted counterbalancing effects on the basal activity on both promoters. Our results identify the contributions of specific interactions to the activity of the hERalpha, and support the concept that this region couples ligand-binding with ER activity.
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Affiliation(s)
- Changqing Zhao
- Department of Physiology, Wayne State University School of Medicine, 540 East Canfield Avenue, Detroit, MI 48201-1928, USA
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23
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Zhu YS, Cai LQ, Huang Y, Fish J, Wang L, Zhang ZK, Imperato-McGinley JL. Receptor isoform and ligand-specific modulation of dihydrotestosterone-induced prostate specific antigen gene expression and prostate tumor cell growth by estrogens. JOURNAL OF ANDROLOGY 2005; 26:500-8; discussion 509-10. [PMID: 15955889 PMCID: PMC1557648 DOI: 10.2164/jandrol.05002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Androgens via the androgen receptor (AR) play crucial roles in prostate physiology and pathophysiology. These androgen actions can be either inhibited or potentiated by estrogens. The mechanisms of these seemingly opposing estrogen effects are unclear. We studied the effects of estrogens on the modulation of androgen induction of prostate specific antigen (PSA) gene expression and prostate tumor cell growth. Cotransfection analyses in CV-1, DU-145, and PC-3 cells showed that dihydrotestosterone (DHT)-induced PSA transcription activity was inhibited by 17beta-estradiol, diethylstilbestrol, ICI182780, and 17alpha-estradiol, but not by tamoxifen via estrogen receptor alpha (ERalpha). In the presence of ERbeta, 17beta-estradiol and diethylstilbestrol had no significant effect, while 17alpha-estradiol inhibited and ICI182780 and tamoxifen potentiated DHT action. When both ERalpha and ERbeta were present, all ER-ligands except tamoxifen inhibited DHT action. The inhibition of DHT action by 17beta-estradiol via ERalpha was mainly dependent on the DNA binding domain, while the 17alpha-estradiol effect was mainly dependent on the ERalpha carboxyl terminus. Treatment with DHT in LAPC-4 prostate tumor cells that express a wild-type AR and both ERbeta and ERalpha greatly increased the PSA gene expression and cell growth. These DHT effects were significantly attenuated by the addition of 17alpha-estradiol, 17beta-estradiol, or cyproterone acetate in a dose-dependent manner. These results indicate that estrogens produce an ER-isoform- and ER-ligand-specific modulation of DHT induction of PSA gene expression and prostate tumor cell growth, providing a molecular basis for designing favorable agents for the prevention and control of prostate cancer.
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Affiliation(s)
- Yuan-Shan Zhu
- Department of Medicine/Endocrinology, Weill Medical College of Cornell University, 1300 York Ave, Box 149, New York, NY 10021, USA.
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24
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Affiliation(s)
- Yuan-Shan Zhu
- Associate Professor of Medicine, Department of Medicine/Endocrinology, Weill Medical College of Cornell University, 1300 York Avenue, Box 149, New York, New York 10021
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25
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Petrescu AD, Hertz R, Bar-Tana J, Schroeder F, Kier AB. Role of regulatory F-domain in hepatocyte nuclear factor-4alpha ligand specificity. J Biol Chem 2005; 280:16714-27. [PMID: 15741159 DOI: 10.1074/jbc.m405906200] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The F-domain of rat HNF-4alpha1 has a crucial impact on the ligand binding affinity, ligand specificity and secondary structure of HNF-4alpha. (i) Fluorescent binding assays indicate that wild-type, full-length HNF-4alpha (amino acids 1-455) has high affinity (Kd=0.06-12 nm) for long chain fatty acyl-CoAs (LCFA-CoA) and low affinity (Kd=58-296 nm) for unesterified long chain fatty acids (LCFAs). LCFA-CoA binding was due to close molecular interaction as shown by fluorescence resonance energy transfer (FRET) from full-length HNF-4alpha tryptophan (FRET donor) to bound cis-parinaroyl-CoA (FRET acceptor), which yielded an intermolecular distance of 33 A, although no FRET to cis-parinaric acid was detected. (ii) Deleting the N-terminal A-D-domains, comprising the AF1 and DNA binding functions, only slightly affected affinities for LCFA-CoAs (Kd=0.9-4 nm) and LCFAs (Kd=93-581 nm). (iii) Further deletion of the F-domain robustly reduced affinities for LCFA-CoA and reversed ligand specificity (i.e. high affinity for LCFAs (Kd=1.5-32 nm) and low affinity for LCFA-CoAs (Kd=54-302 nm)). No FRET from HNF-4alpha-E (amino acids 132-370) tryptophan (FRET donor) to bound cis-parinaroyl-CoA (FRET acceptor) was detected, whereas an intermolecular distance of 28 A was calculated from FRET between HNF-4alpha-E and cis-parinaric acid. (iv) Circular dichroism showed that LCFA-CoA, but not LCFA, altered the secondary structure of HNF-4alpha only when the F-domain was present. (v) cis-Parinaric acid bound to HNF-4alpha with intact F-domain was readily displaceable by S-hexadecyl-CoA, a nonhydrolyzable thioether analogue of LCFA-CoAs. Truncation of the F-domain significantly decreased cis-parinaric acid displacement. Hence, the C-terminal F-domain of HNF-4alpha regulated ligand affinity, ligand specificity, and ligand-induced conformational change of HNF-4alpha. Thus, characteristics of F-domain-truncated mutants may not reflect the properties of full-length HNF-4alpha.
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Affiliation(s)
- Anca D Petrescu
- Department of Physiology and Pharmacology, Texas A&M University, Texas Veterinary Medical Center, College Station 77843-4467, USA
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Abstract
As early as the 1800s, the actions of estrogen have been implicated in the development and progression of breast cancer. The estrogen receptor (ER) was identified in the late 1950s and purified a few years later. However, it was not until the 1980s that the first ER was molecularly cloned, and in the mid 1990s, a second ER was cloned. These two related receptors are now called ERalpha and ERbeta, respectively. Since their discovery, much research has focused on identifying alterations within the coding sequence of these receptors in clinical samples. As a result, a large number of naturally occurring splice variants of both ERalpha and ERbeta have been identified in normal epithelium and diseased or cancerous tissues. In contrast, only a few point mutations have been identified in human patient samples from a variety of disease states, including breast cancer, endometrial cancer, and psychiatric diseases. To elucidate the mechanism of action for these variant isoforms or mutant receptors, experimental mutagenesis has been used to analyze the function of distinct amino acid residues in the ERs. This review will focus on ERalpha and ERbeta alterations in breast cancer.
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Affiliation(s)
- Matthew H Herynk
- Breast Center, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA
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Farboud B, Privalsky ML. Retinoic acid receptor-alpha is stabilized in a repressive state by its C-terminal, isotype-specific F domain. Mol Endocrinol 2004; 18:2839-53. [PMID: 15331758 DOI: 10.1210/me.2004-0236] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Retinoic acid receptors (RARs) are hormone-regulated transcription factors that play multiple roles in vertebrate development and differentiation. Three isotypes of RARs, alpha, beta, and gamma, are encoded by distinct genetic loci and possess distinct transcriptional properties. Typically, RARalpha represses target gene transcription in the absence of hormone, whereas RARbeta and gamma fail to repress under these conditions. This inability of RARbeta and RARgamma to repress transcription is due to intramolecular interactions between helix 3 and helix 12 of the hormone binding domains of these isotypes that inhibit corepressor binding while favoring coactivator binding. We report here that the converse ability of RARalpha to repress requires the integrity of the receptor F domain, a domain that maps C-terminal to helix 12, varies in sequence among different nuclear receptors, and is of poorly understood function. The F domain appears to help stabilize helix 12 of RARalpha in a more open position that enhances corepressor binding and inhibits coactivator binding in the absence of hormone. Intriguingly, the RARalpha F domain is isotype autonomous in its function. We speculate that the RARalpha F domain may dock elsewhere on the receptor surface, and this intramolecular interaction may maintain RARalpha helix 12 in an open, repression-competent conformation.
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Affiliation(s)
- Behnom Farboud
- Section of Microbiology, Division of Biological Sciences, One Shields Avenue, University of California at Davis, Davis, California 95616, USA
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Wu X, Hopkins PM, Palli SR, Durica DS. Crustacean retinoid-X receptor isoforms: distinctive DNA binding and receptor-receptor interaction with a cognate ecdysteroid receptor. Mol Cell Endocrinol 2004; 218:21-38. [PMID: 15130508 DOI: 10.1016/j.mce.2003.12.013] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2003] [Revised: 12/17/2003] [Accepted: 12/22/2003] [Indexed: 11/23/2022]
Abstract
We have identified cDNA clones that encode homologs of the ecdysteroid receptor (EcR) and retinoid-X receptor (RXR)/USP classes of nuclear receptors from the fiddler crab Uca pugilator (UpEcR and UpRXR). Several UpRXR cDNA splicing variants were found in coding regions that could potentially influence function. A five-amino acid (aa) insertion/deletion is located in the "T" box in the hinge region. Another 33-aa insertion/deletion is found inside the ligand-binding domain (LBD), between helix 1 and helix 3. Ribonuclease protection assays (RPA) showed that four UpRXR transcripts [UpRXR(+5+33), UpRXR(-5+33), UpRXR(+5-33) and UpRXR(-5-33)] were present in regenerating limb buds. UpRXR(-5+33) was the most abundant transcript present in regenerating limb buds in both early blastema and late premolt growth stages. Expression vectors for these UpRXR variants and UpEcR were constructed, and the proteins expressed in E. coli and in vitro expression systems. The expressed crab nuclear receptors were then characterized by electrophoretic mobility shift assay (EMSA) and glutathione S-transferase (GST) pull down experiments. EMSA results showed that UpEcR/UpRXR(-5+33) heterocomplexes bound with a series of hormone response elements (HREs) including eip28/29, IRper-1, DR-4, and IRhsp-1 with appreciable affinity. Competition EMSA also showed that the affinity decreased as sequence composition deviated from a perfect consensus element. Binding to IRper-1 HREs occurred only if the heterodimer partner UpRXR contained the 33-aa LBD insertion. UpRXR lacking both the 5-aa and 33-aa insertion bound to a DR-1G HRE in the absence of UpEcR. The results of GST-pull down experiments showed that UpEcR interacted only with UpRXR variants containing the 33-aa insertion, and not with those lacking the 33-aa insertion. These in vitro receptor protein-DNA and receptor protein-protein interactions occurred in the absence of hormone (20-hydroxyecdysone and 9-cis retinoid acid, 9-cis RA). Transactivation studies using a hybrid UpEcR ligand-binding domain construct and UpRXR (+/-33) ligand-binding domain constructs also showed that the 33-aa insertion was indispensable in mediating ecdysteroid stimulated transactivation.
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Affiliation(s)
- Xiaohui Wu
- Department of Zoology, University of Oklahoma, Norman, OK 73019, USA
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Clarke R, Liu MC, Bouker KB, Gu Z, Lee RY, Zhu Y, Skaar TC, Gomez B, O'Brien K, Wang Y, Hilakivi-Clarke LA. Antiestrogen resistance in breast cancer and the role of estrogen receptor signaling. Oncogene 2003; 22:7316-39. [PMID: 14576841 DOI: 10.1038/sj.onc.1206937] [Citation(s) in RCA: 347] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Antiestrogens include agents such as tamoxifen, toremifene, raloxifene, and fulvestrant. Currently, tamoxifen is the only drug approved for use in breast cancer chemoprevention, and it remains the treatment of choice for most women with hormone receptor positive, invasive breast carcinoma. While antiestrogens have been available since the early 1970s, we still do not fully understand their mechanisms of action and resistance. Essentially, two forms of antiestrogen resistance occur: de novo resistance and acquired resistance. Absence of estrogen receptor (ER) expression is the most common de novo resistance mechanism, whereas a complete loss of ER expression is not common in acquired resistance. Antiestrogen unresponsiveness appears to be the major acquired resistance phenotype, with a switch to an antiestrogen-stimulated growth being a minor phenotype. Since antiestrogens compete with estrogens for binding to ER, clinical response to antiestrogens may be affected by exogenous estrogenic exposures. Such exposures include estrogenic hormone replacement therapies and dietary and environmental exposures that directly or indirectly increase a tumor's estrogenic environment. Whether antiestrogen resistance can be conferred by a switch from predominantly ERalpha to ERbeta expression remains unanswered, but predicting response to antiestrogen therapy requires only measurement of ERalpha expression. The role of altered receptor coactivator or corepressor expression in antiestrogen resistance also is unclear, and understanding their roles may be confounded by their ubiquitous expression and functional redundancy. We have proposed a gene network approach to exploring the mechanistic aspects of antiestrogen resistance. Using transcriptome and proteome analyses, we have begun to identify candidate genes that comprise one component of a larger, putative gene network. These candidate genes include NFkappaB, interferon regulatory factor-1, nucleophosmin, and the X-box binding protein-1. The network also may involve signaling through ras and MAPK, implicating crosstalk with growth factors and cytokines. Ultimately, signaling affects the expression/function of the proliferation and/or apoptotic machineries.
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Affiliation(s)
- Robert Clarke
- Department of Oncology and Vincent T. Lombardi Cancer Center, Georgetown University School of Medicine, 3970 Reservoir Road NW, Washington, DC 20057, USA.
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Kim K, Thu N, Saville B, Safe S. Domains of estrogen receptor alpha (ERalpha) required for ERalpha/Sp1-mediated activation of GC-rich promoters by estrogens and antiestrogens in breast cancer cells. Mol Endocrinol 2003; 17:804-17. [PMID: 12576490 DOI: 10.1210/me.2002-0406] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Estrogen receptor alpha (ERalpha)/Sp1 activation of GC-rich gene promoters in breast cancer cells is dependent, in part, on activation function 1 (AF1) of ERalpha, and this study investigates contributions of the DNA binding domain (C) and AF2 (DEF) regions of ERalpha on activation of ERalpha/Sp1. 17Beta-estradiol (E2) and the antiestrogens 4-hydroxytamoxifen and ICI 182,780 induced reporter gene activity in MCF-7 and MDA-MB-231 cells cotransfected with human or mouse ERalpha (hERalpha or MOR), but not ERbeta and GC-rich constructs containing three tandem Sp1 binding sites (pSp13) or other E2-responsive GC-rich promoters. Estrogen and antiestrogen activation of hERalpha/Sp1 was dependent on overlapping and different regions of the C, D, E, and F domains of ERalpha. Antiestrogen-induced activation of hERalpha/Sp1 was lost using hERalpha mutants deleted in zinc finger 1 [amino acids (aa) 185-205], zinc finger 2 (aa 218-245), and the hinge/helix 1 (aa 265-330) domains. In contrast with antiestrogens, E2-dependent activation of hERalpha/Sp1 required the C-terminal F domain (aa 579-595), which contains a beta-strand structural motif. Moreover, in peptide competition experiments overexpression of a C-terminal (aa 575-595) F domain peptide specifically blocked E2-dependent activation of hERalpha/Sp1, suggesting that F domain interactions with nuclear cofactors are required for ERalpha/Sp1 action.
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Affiliation(s)
- Kyounghyun Kim
- Department of Veterinary Physiology & Pharmacology, Texas A&M University, College Station, Texas 77843-4466, USA
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