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Ge Y, Ni X, Li J, Ye M, Jin X. Roles of estrogen receptor α in endometrial carcinoma (Review). Oncol Lett 2023; 26:530. [PMID: 38020303 PMCID: PMC10644365 DOI: 10.3892/ol.2023.14117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 10/06/2023] [Indexed: 12/01/2023] Open
Abstract
Endometrial carcinoma (EC) is a group of endometrial epithelial malignancies, most of which are adenocarcinomas and occur in perimenopausal and postmenopausal women. It is one of the most common carcinomas of the female reproductive system. It has been shown that the occurrence and development of EC is closely associated with the interaction between estrogen (estradiol, E2) and estrogen receptors (ERs), particularly ERα. As a key nuclear transcription factor, ERα is a carcinogenic factor in EC. Its interactions with upstream and downstream effectors and co-regulators have important implications for the proliferation, metastasis, invasion and inhibition of apoptosis of EC. In the present review, the structure of ERα and the regulation of ERα in multiple dimensions are described. In addition, the classical E2/ERα signaling pathway and the crosstalk between ERα and other EC regulators are elucidated, as well as the therapeutic targeting of ERα, which may provide a new direction for clinical applications of ERα in the future.
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Affiliation(s)
- Yidong Ge
- Department of Medical Oncology, The First Hospital of Ningbo University, Ningbo University, Ningbo, Zhejiang 315020, P.R. China
- Zhejiang Key Laboratory of Pathophysiology, Department of Biochemistry and Molecular Biology, Health Science Center, Ningbo University, Ningbo, Zhejiang 315211, P.R. China
| | - Xiaoqi Ni
- Department of Medical Oncology, The First Hospital of Ningbo University, Ningbo University, Ningbo, Zhejiang 315020, P.R. China
- Zhejiang Key Laboratory of Pathophysiology, Department of Biochemistry and Molecular Biology, Health Science Center, Ningbo University, Ningbo, Zhejiang 315211, P.R. China
| | - Jingyun Li
- Department of Medical Oncology, The First Hospital of Ningbo University, Ningbo University, Ningbo, Zhejiang 315020, P.R. China
- Zhejiang Key Laboratory of Pathophysiology, Department of Biochemistry and Molecular Biology, Health Science Center, Ningbo University, Ningbo, Zhejiang 315211, P.R. China
| | - Meng Ye
- Department of Medical Oncology, The First Hospital of Ningbo University, Ningbo University, Ningbo, Zhejiang 315020, P.R. China
- Zhejiang Key Laboratory of Pathophysiology, Department of Biochemistry and Molecular Biology, Health Science Center, Ningbo University, Ningbo, Zhejiang 315211, P.R. China
| | - Xiaofeng Jin
- Department of Medical Oncology, The First Hospital of Ningbo University, Ningbo University, Ningbo, Zhejiang 315020, P.R. China
- Zhejiang Key Laboratory of Pathophysiology, Department of Biochemistry and Molecular Biology, Health Science Center, Ningbo University, Ningbo, Zhejiang 315211, P.R. China
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2
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Kuo SH, Yang SY, You SL, Lien HC, Lin CH, Lin PH, Huang CS. Polymorphisms of ESR1, UGT1A1, HCN1, MAP3K1 and CYP2B6 are associated with the prognosis of hormone receptor-positive early breast cancer. Oncotarget 2017; 8:20925-20938. [PMID: 28178648 PMCID: PMC5400556 DOI: 10.18632/oncotarget.14995] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 01/03/2017] [Indexed: 12/22/2022] Open
Abstract
In this study, we investigated whether single nucleotide polymorphisms (SNPs) identified by genome-wide association study (GWAS) (MAP3K1, FGFR2, TNRC9, HCN1, and 5p12), and SNPs involved in the metabolism of estrogen (CYP19, COMT, ESR1, and UGT1A1), tamoxifen (CYP2C9, CYP2C19, CYP3A5, and CYP2D6), and chemotherapeutic agents (ABCB1, ALDH3A1, and CYP2B6) are associated with the prognoses of 414 hormone receptor (HR)-positive early breast cancers with negative or 1 to 3 nodal metastases. At a median follow-up period of 10.6 years, 363 patients were alive, and 51 (12.3%) had died. Multiple-adjusted hazard ratios (aHRs) and the corresponding 95% confidence intervals for distant disease-free survival (DDFS), disease-free survival (DFS), and overall survival (OS) in association with the genotypes of 34 SNPs from the above-mentioned 16 genes were evaluated, using the stepwise selection Cox model. We found that the SNP, ESR1-codon325 rs1801132 (G/G+G/C), was associated with a longer DDFS, whereas UGT1A1 rs4148323 (A/A+A/G), and HCN1 rs981782 (A/A+A/C) were significantly associated with poorer DDFS. MAP3K1 rs889312 (C/C) and CYP2B6 rs3211371 (T/C) were significantly associated with poor DFS, DDFS and OS. Among premenopausal women, MAP3K1 rs889312 (C/C), CYP2B6 rs3211371 (T/C), CYP2B6 rs4802101 (T/T), ABCB1 rs2032582 (C/C), and ALDH3A1 rs2231142 (G/G) were significantly associated with poor DDFS, DFS, or OS. Our results provide additional evidence that genetic polymorphisms observed in SNPs are associated with the prognoses of patients with HR-positive breast cancers; this may indicate different treatment strategies for these patients.
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Affiliation(s)
- Sung-Hsin Kuo
- Department of Oncology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.,Graduate Institute of Oncology, National Taiwan University College of Medicine, Taipei, Taiwan.,Cancer Research Center, National Taiwan University College of Medicine, Taipei, Taiwan.,National Taiwan University Cancer Center, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Shi-Yi Yang
- Graduate Institute of Epidemiology, College of Public Health, National Taiwan University, Taipei, Taiwan
| | - San-Lin You
- School of Medicine, College of Medicine, Fu-Jen Catholic University, New Taipei, Taiwan.,Big Data Research Center, Fu-Jen Catholic University, New Taipei, Taiwan
| | - Huang-Chun Lien
- Department of Pathology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
| | - Ching-Hung Lin
- Department of Oncology, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.,Cancer Research Center, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Po-Han Lin
- Department of Medical Genetics, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
| | - Chiun-Sheng Huang
- Department of Surgery, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
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3
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Pham TT, Angus SP, Johnson GL. MAP3K1: Genomic Alterations in Cancer and Function in Promoting Cell Survival or Apoptosis. Genes Cancer 2014; 4:419-26. [PMID: 24386504 DOI: 10.1177/1947601913513950] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Accepted: 11/02/2013] [Indexed: 12/15/2022] Open
Abstract
MAP3K1 is a member of the mitogen-activated protein kinase kinase kinase (MAP3K) family of serine/threonine kinases. MAP3K1 regulates JNK activation and is unique among human kinases in that it also encodes an E3 ligase domain that ubiquitylates c-Jun and ERK1/2. Full length MAP3K1 regulates cell migration and contributes to pro-survival signaling while its caspase 3-mediated cleavage generates a C-terminal kinase domain that promotes apoptosis. The critical function of MAP3K1 in cell fate decisions suggests that it may be a target for deregulation in cancer. Recent large-scale genomic studies have revealed that MAP3K1 copy number loss and somatic missense or nonsense mutations are observed in a significant number of different cancers, being most prominent in luminal breast cancer. The alteration of MAP3K1 in diverse cancer types demonstrates the importance of defining phenotypes for possible therapeutic targeting of tumor cell vulnerabilities created when MAP3K1 function is lost or gained.
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Affiliation(s)
- Trang T Pham
- Department of Pharmacology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Steven P Angus
- Department of Pharmacology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Gary L Johnson
- Department of Pharmacology, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine, Chapel Hill, NC, USA
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4
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Williams KA, Zhang M, Xiang S, Hu C, Wu JY, Zhang S, Ryan M, Cox AD, Der CJ, Fang B, Koomen J, Haura E, Bepler G, Nicosia SV, Matthias P, Wang C, Bai W, Zhang X. Extracellular signal-regulated kinase (ERK) phosphorylates histone deacetylase 6 (HDAC6) at serine 1035 to stimulate cell migration. J Biol Chem 2013; 288:33156-70. [PMID: 24089523 DOI: 10.1074/jbc.m113.472506] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Histone deacetylase 6 (HDAC6) is well known for its ability to promote cell migration through deacetylation of its cytoplasmic substrates such as α-tubulin. However, how HDAC6 itself is regulated to control cell motility remains elusive. Previous studies have shown that one third of extracellular signal-regulated kinase (ERK) is associated with the microtubule cytoskeleton in cells. Yet, no connection between HDAC6 and ERK has been discovered. Here, for the first time, we reveal that ERK binds to and phosphorylates HDAC6 to promote cell migration via deacetylation of α-tubulin. We have identified two novel ERK-mediated phosphorylation sites: threonine 1031 and serine 1035 in HDAC6. Both sites were phosphorylated by ERK1 in vitro, whereas Ser-1035 was phosphorylated in response to the activation of EGFR-Ras-Raf-MEK-ERK signaling pathway in vivo. HDAC6-null mouse embryonic fibroblasts rescued by the nonphosphorylation mimicking mutant displayed significantly reduced cell migration compared with those rescued by the wild type. Consistently, the nonphosphorylation mimicking mutant exerted lower tubulin deacetylase activity in vivo compared with the wild type. These data indicate that ERK/HDAC6-mediated cell motility is through deacetylation of α-tubulin. Overall, our results suggest that HDAC6-mediated cell migration could be governed by EGFR-Ras-Raf-MEK-ERK signaling.
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Affiliation(s)
- Kendra A Williams
- From the Department of Pathology and Cell Biology, University of South Florida Morsani College of Medicine, Tampa, Florida 33612
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Estradiol and tamoxifen induce cell migration through GPR30 and activation of focal adhesion kinase (FAK) in endometrial cancers with low or without nuclear estrogen receptor α (ERα). PLoS One 2013; 8:e72999. [PMID: 24039841 PMCID: PMC3767783 DOI: 10.1371/journal.pone.0072999] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Accepted: 07/16/2013] [Indexed: 12/24/2022] Open
Abstract
Estrogens and tamoxifen (an antiestrogen) exert their actions by activation of estrogen receptor (ER) through genomic and non-genomic mechanisms and are implicated in the development of endometrial cancer. Previous reports have demonstrated that estradiol and tamoxifen induce proliferation of human endometrial cancer cells through GPR30 (non-genomic ER) signaling pathway. Herein, we demonstrate that phosphorylation of focal adhesion kinase (FAK) is involved in cell migration induced by estradiol, tamoxifen and G1 (a GPR30 agonist) through the transmembrane ER (GPR30) in endometrial cancer cell lines with or without ERα (Ishikawa and RL95-2). Additionally, the GPR30-mediated cell migration was further abolished by administration of either specific RNA interference targeting GPR30 or an FAK inhibitor. Moreover, we have validated that the signaling between GPR30 and phosphorylated FAK is indeed mediated by the EGFR/PI3K/ERK pathway. Clinically, a significant correlation between levels of GPR30 and phophorylated FAK (pFAK) observed in human endometrial cancer tissues with low or without ERα further suggested that estrogen-induced phosphorylation of FAK and cell migration were most likely triggered by GPR30 activation. These results provided new insights for understanding the pathophysiological functions of GPR30 in human endometrial cancers.
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6
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Zhou C, Steplowski TA, Dickens HK, Malloy KM, Gehrig PA, Boggess JF, Bae-Jump VL. Estrogen induction of telomerase activity through regulation of the mitogen-activated protein kinase (MAPK) dependent pathway in human endometrial cancer cells. PLoS One 2013; 8:e55730. [PMID: 23409030 PMCID: PMC3567109 DOI: 10.1371/journal.pone.0055730] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Accepted: 12/29/2012] [Indexed: 12/21/2022] Open
Abstract
Given that prolonged exposure to estrogen and increased telomerase activity are associated with endometrial carcinogenesis, our objective was to evaluate the interaction between the MAPK pathway and estrogen induction of telomerase activity in endometrial cancer cells. Estradiol (E2) induced telomerase activity and hTERT mRNA expression in the estrogen receptor (ER)-α positive, Ishikawa endometrial cancer cell line. UO126, a highly selective inhibitor of MEK1/MEK2, inhibited telomerase activity and hTERT mRNA expression induced by E2. Similar results were also found after transfection with ERK 1/2-specific siRNA. Treatment with E2 resulted in rapid phosphorylation of p44/42 MAPK and increased MAPK activity which was abolished by UO126. The hTERT promoter contains two estrogen response elements (EREs), and luciferase assays demonstrate that these EREs are activated by E2. Exposure to UO126 or ERK 1/2-specific siRNA in combination with E2 counteracted the stimulatory effect of E2 on luciferase activity from these EREs. These findings suggest that E2-induction of telomerase activity is mediated via the MAPK pathway in human endometrial cancer cells.
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Affiliation(s)
- Chunxiao Zhou
- Division of Gynecological Oncology, Department of Obstetrics and Gynecology, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Tara A. Steplowski
- Department of Otolaryngology, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Hallum K. Dickens
- Division of Gynecological Oncology, Department of Obstetrics and Gynecology, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Kimberly M. Malloy
- Division of Gynecological Oncology, Department of Obstetrics and Gynecology, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Paola A. Gehrig
- Division of Gynecological Oncology, Department of Obstetrics and Gynecology, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - John F. Boggess
- Division of Gynecological Oncology, Department of Obstetrics and Gynecology, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Victoria L. Bae-Jump
- Division of Gynecological Oncology, Department of Obstetrics and Gynecology, University of North Carolina, Chapel Hill, North Carolina, United States of America
- * E-mail:
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7
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Collins-Burow BM, Antoon JW, Frigo DE, Elliott S, Weldon CB, Boue SM, Beckman BS, Curiel TJ, Alam J, McLachlan JA, Burow ME. Antiestrogenic activity of flavonoid phytochemicals mediated via the c-Jun N-terminal protein kinase pathway. Cell-type specific regulation of estrogen receptor alpha. J Steroid Biochem Mol Biol 2012; 132:186-93. [PMID: 22634477 PMCID: PMC4083692 DOI: 10.1016/j.jsbmb.2012.05.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 05/12/2012] [Accepted: 05/14/2012] [Indexed: 12/14/2022]
Abstract
Flavonoid phytochemicals act as both agonists and antagonists of the human estrogen receptors (ERs). While a number of these compounds act by directly binding to the ER, certain phytochemicals, such as the flavonoid compounds chalcone and flavone, elicit antagonistic effects on estrogen signaling independent of direct receptor binding. Here we demonstrate both chalcone and flavone function as cell type-specific selective ER modulators. In MCF-7 breast carcinoma cells chalcone and flavone suppress ERα activity through stimulation of the stress-activated members of the mitogen-activated protein kinase (MAPK) family: c-Jun N-terminal kinase (JNK)1 and JNK2. The use of dominant-negative mutants of JNK1 or JNK2 in stable transfected cells established that the antiestrogenic effects of chalcone and flavone required intact JNK signaling. We further show that constitutive activation of the JNK pathway partially suppresses estrogen (E2)-mediated gene expression in breast, but not endometrial carcinoma cells. Our results demonstrate a role for stress-activated MAPKs in the cell type-specific regulation of ERα function.
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Affiliation(s)
- Bridgette M. Collins-Burow
- Tulane University Medical Center, New Orleans, Louisiana 70112
- Center for Bioenvironmental Research at Tulane and Xavier Universities, New Orleans, Louisiana 70112
- Department of Medicine, Section of Hematology & Medical Oncology, New Orleans, Louisiana 70112
| | - James W. Antoon
- Tulane University Medical Center, New Orleans, Louisiana 70112
- Department of Medicine, Section of Hematology & Medical Oncology, New Orleans, Louisiana 70112
- Department of Pharmacology, New Orleans, Louisiana 70112
| | - Daniel E. Frigo
- Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX
| | - Steven Elliott
- Tulane University Medical Center, New Orleans, Louisiana 70112
- Department of Medicine, Section of Hematology & Medical Oncology, New Orleans, Louisiana 70112
| | - Christopher B. Weldon
- Tulane University Medical Center, New Orleans, Louisiana 70112
- Department of Medicine, Section of Hematology & Medical Oncology, New Orleans, Louisiana 70112
| | - Stephen M. Boue
- U. S. Department of Agriculture, Agricultural Research Service, Southern Regional Research Center, New Orleans, LA 70179
| | - Barbara S. Beckman
- Center for Bioenvironmental Research at Tulane and Xavier Universities, New Orleans, Louisiana 70112
- Department of Medicine, Section of Hematology & Medical Oncology, New Orleans, Louisiana 70112
| | - Tyler J. Curiel
- Cancer Therapy & Research Center, University of Texas Health Science Center, San Antonio
| | - Jawed Alam
- Alton Ochsner Medical Foundation, Department of Molecular Genetics, New Orleans, Louisiana 70121
| | - John A. McLachlan
- Tulane University Medical Center, New Orleans, Louisiana 70112
- Center for Bioenvironmental Research at Tulane and Xavier Universities, New Orleans, Louisiana 70112
| | - Matthew E. Burow
- Tulane University Medical Center, New Orleans, Louisiana 70112
- Center for Bioenvironmental Research at Tulane and Xavier Universities, New Orleans, Louisiana 70112
- Department of Medicine, Section of Hematology & Medical Oncology, New Orleans, Louisiana 70112
- To whom correspondence and requests for reprints should be addressed: Matthew E. Burow, Tulane University Health Sciences Center, Department of Medicine, Section of Hematology & Medical Oncology, 1430 Tulane Ave. SL-78, New Orleans, LA 70112, Phone: 504-988-6688, Fax: 504-988-5483,
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8
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Shen Z, Zhang X, Tang J, Kasiappan R, Jinwal U, Li P, Hann S, Nicosia SV, Wu J, Zhang X, Bai W. The coupling of epidermal growth factor receptor down regulation by 1alpha,25-dihydroxyvitamin D3 to the hormone-induced cell cycle arrest at the G1-S checkpoint in ovarian cancer cells. Mol Cell Endocrinol 2011; 338:58-67. [PMID: 21458521 PMCID: PMC3089697 DOI: 10.1016/j.mce.2011.02.023] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Revised: 02/02/2011] [Accepted: 02/24/2011] [Indexed: 01/14/2023]
Abstract
1alpha,25-dihydroxyvitamin D3, 1,25(OH)(2)D(3), regulates gene expression through the vitamin D receptor. The present studies identify the epidermal growth factor receptor, EGFR, as a target gene suppressed by 1,25(OH)(2)D(3) in human ovarian cancer cells. The suppression was detected at both mRNA and protein levels in vitamin D-sensitive human ovarian cancer cells. A novel vitamin D response element was identified in intron 1 of the EGFR genome, a known hotspot for its transcriptional regulation. Chromatin immunoprecipitations and reporter gene analyses showed that the intronic DNA element bound to vitamin D receptor and a co-repressor and was functional in mediating transcriptional suppression of EGFR promoter by 1,25(OH)(2)D(3) under stable transfection conditions. Consistent with the EGFR down regulation, 1,25(OH)(2)D(3) suppressed activation of the external signal regulated kinase by epidermal growth factors. Over expression of an active EGFR in vitamin D sensitive ovarian cancer cells caused resistance to 1,25(OH)(2)D(3)-induced growth suppression and diminished the hormonal regulation of cyclin D1, cyclin E, Skp2 and p27, a group of cell cycle regulators that mediate 1,25(OH)(2)D(3)-induced cell cycle arrest at G1-S checkpoint. Taken together, our studies demonstrate that 1,25(OH)(2)D(3) suppresses the response of human ovarian cancer cells to mitogenic growth factors and couple the suppression to the cell cycle arrest at G1-S checkpoint by the hormone.
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Affiliation(s)
- Zheng Shen
- Department of Pathology and Cell Biology, USF College of Medicine, Tampa, FL 33612-4799, United States
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9
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Rosenblatt AE, Garcia MI, Lyons L, Xie Y, Maiorino C, Désiré L, Slingerland J, Burnstein KL. Inhibition of the Rho GTPase, Rac1, decreases estrogen receptor levels and is a novel therapeutic strategy in breast cancer. Endocr Relat Cancer 2011; 18:207-19. [PMID: 21118977 PMCID: PMC3644524 DOI: 10.1677/erc-10-0049] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Rac1, a Rho GTPase, modulates diverse cellular processes and is hyperactive in some cancers. Estrogen receptor-alpha (ERα) in concert with intracellular signaling pathways regulates genes associated with cell proliferation, tumor development, and breast cancer cell survival. Therefore, we examined the possibility of Rac1 and ERα crosstalk in breast cancer cells. We found that Rac1 enhanced ERα transcriptional activity in breast cancer cells. Vav3, a Rho guanine nucleotide exchange factor that activates Rac1, was an upstream mediator, and P21/Cdc42/Rac1 activating kinase-1 (Pak-1) was a downstream effector of Rac1 enhancement of ERα activity. These results suggest that Rac1 may prove to be a therapeutic target. To test this hypothesis, we used a small molecule Rac inhibitor, EHT 1864, and found that EHT 1864 inhibited ERα transcriptional activity. Furthermore, EHT 1864 inhibited estrogen-induced cell proliferation in breast cancer cells and decreased tamoxifen-resistant breast cancer cell growth. EHT 1864 decreased activity of the promoter of the ERα gene resulting in down-regulation of ERα mRNA and protein levels. Therefore, ERα down-regulation by EHT 1864 is the likely mechanism of EHT 1864-mediated inhibition of ERα activity and estrogen-stimulated breast cancer cell proliferation. Since ERα plays a critical role in the pathogenesis of breast cancer and the Rac inhibitor EHT 1864 down-regulates ERα expression and breast cancer cell proliferation, further investigation of the therapeutic potential of Rac1 targeting in the treatment of breast cancer is warranted.
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Affiliation(s)
- Adena E Rosenblatt
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, 1600 Northwest 10th Avenue (R-189), Miami, Florida 33136, USA
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10
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Abstract
The transcriptional activity of the androgen receptor is regulated by both ligand binding and posttranslational modifications including acetylation and SUMOylation. Histone deacetylases are known to catalyze the removal of acetyl groups from both histones and non-histone proteins. In the present study, we report that histone deacetylase 4 (HDAC4) binds to and inhibits the activity of the androgen receptor (AR). This inhibition was found to depend on the SUMOylation, instead of deacetylation, of the AR. Consistently, HDAC4 increases the level of AR SUMOylation in both whole cell and cell-free assay systems, raising the possibility that the deacetylase may act as an E3 ligase for AR SUMOylation. Knock down of HDAC4 increases the activity of endogenous AR and androgen induction of prostate specific antigen expression and prostate cancer cell growth, which is associated with decreased SUMOylation of the receptor. Overall, the studies identify HDAC4 as a positive regulator for AR SUMOylation, revealing a deacetylase-independent mechanism of histone deacetylase action in prostate cancer cells.
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11
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Barone I, Brusco L, Fuqua SAW. Estrogen receptor mutations and changes in downstream gene expression and signaling. Clin Cancer Res 2010; 16:2702-8. [PMID: 20427689 DOI: 10.1158/1078-0432.ccr-09-1753] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Estrogens play a crucial role in regulating the growth and differentiation of breast cancers, with approximately two thirds of all breast tumors expressing the estrogen receptor alpha (ERalpha). Therefore, therapeutic strategies directed at inhibiting the action of ERalpha by using anti-estrogens such as tamoxifen, or reducing estrogens levels by using aromatase inhibitors, such as letrozole, anastrozole, or exemestane, are the standard treatments offered to women with ERalpha-positive cancer. However, not all patients respond to endocrine therapies (termed de novo resistance), and a large number of patients who do respond will eventually develop disease progression or recurrence while on therapy (acquired resistance). Recently, variant forms of the receptor have been identified owing to alternative splicing or gene mutation. This article reviews these variant receptors and their clinical relevance in resistance to endocrine therapy, by addressing their molecular cross-talk with growth factor receptors and signaling components. Understanding the complexity of receptor-mediated signaling has promise for new combined therapeutic options that focus on more efficient blockade of receptor cross-talk.
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Affiliation(s)
- Ines Barone
- Centro Sanitario and Department of Cellular Biology, University of Calabria, Arcavacata di Rende, Cosenza, Italy
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12
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Carascossa S, Dudek P, Cenni B, Briand PA, Picard D. CARM1 mediates the ligand-independent and tamoxifen-resistant activation of the estrogen receptor alpha by cAMP. Genes Dev 2010; 24:708-19. [PMID: 20360387 DOI: 10.1101/gad.568410] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The estrogen receptor alpha (ERalpha) is activated as a transcription factor by both estrogen and a large variety of other extracellular signals. The mechanisms of this ligand-independent activation, notably by cAMP signaling, are still largely unknown. We now close the gap in the signaling pathway between cAMP and ERalpha. Whereas the direct phosphorylation of ERalpha by the cAMP-activated protein kinase A (PKA) is dispensable, the phosphorylation of the coactivator-associated arginine methyltransferase 1 (CARM1) by PKA at a single serine is necessary and sufficient for direct binding to the unliganded hormone-binding domain (HBD) of ERalpha, and the interaction is necessary for cAMP activation of ERalpha. Sustained PKA activity promoting a constitutive interaction may contribute to tamoxifen resistance of breast tumors. Binding and activation involve a novel regulatory groove of the ERalpha HBD. As a result, depending on the activating signal, ERalpha recruits different coactivator complexes to regulate alternate sets of target genes.
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Affiliation(s)
- Sophie Carascossa
- Département de Biologie Cellulaire, Université de Genève, Sciences III, CH-1211 Genève 4, Switzerland
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Radi ZA, Marusak RA, Morris DL. Species Comparison of the Role of p38 MAP Kinase in the Female Reproductive System. J Toxicol Pathol 2009; 22:109-24. [PMID: 22271984 PMCID: PMC3246056 DOI: 10.1293/tox.22.109] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2009] [Accepted: 04/14/2009] [Indexed: 12/11/2022] Open
Abstract
The p38 mitogen-activated protein kinases (MAPKs) are members of discrete signal
transduction pathways that have significant regulatory roles in a variety of biological
processes, depending on the cell, tissue and organ type. p38 MAPKs are involved in
inflammation, cell growth and differentiation and cell cycle. In the female reproductive
system, p38 MAPKs are known to regulate various aspects of the reproductive process such
as mammalian estrous and menstrual cycles as well as early pregnancy and parturition. p38
MAPKs have also been implicated in alterations and pathologies observed in the female
reproductive system. Therefore, pharmacologic modulation of p38 MAPKs, and inter-connected
signaling pathways (e.g., estrogen receptor signaling, c-fos, c-jun), may influence
reproductive physiology and function. This article provides a critical, comparative review
of available data on the roles of p38 MAPKs in the mammalian female reproductive system
and in reproductive pathophysiology in humans and preclinical species. We first introduce
fundamental differences and similarities of the mammalian female reproductive system that
should be considered by toxicologists and toxicologic pathologists when assessing the
effects of new pharmacologic agents on the female reproductive system. We then explore in
detail the known roles for p38 MAPKs and related molecules in female reproduction. This
foundation is then extended to pathological conditions in which p38 MAPKs are thought to
play an integral role.
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Affiliation(s)
- Zaher A. Radi
- Drug Safety Research & Development, Pfizer Global
R&D, 700 Chesterfield Parkway West, St. Louis, MO 63017, USA
| | | | - Dale L. Morris
- Drug Safety Research & Development, Pfizer Global
R&D, 700 Chesterfield Parkway West, St. Louis, MO 63017, USA
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14
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Lau WS, Chen WF, Chan RYK, Guo DA, Wong MS. Mitogen-activated protein kinase (MAPK) pathway mediates the oestrogen-like activities of ginsenoside Rg1 in human breast cancer (MCF-7) cells. Br J Pharmacol 2009; 156:1136-46. [PMID: 19298253 DOI: 10.1111/j.1476-5381.2009.00123.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND AND PURPOSE The present study was designed to determine how ginsenoside Rg1, an active ingredient in ginseng root, exerts its oestrogenic effects. We hypothesize that Rg1 may exert oestrogen-like actions in MCF-7 cells by activating the mitogen-activated protein kinase (MAPK) pathway in a ligand-independent manner. EXPERIMENTAL APPROACH MCF-7 cells were co-incubated with the MAPK inhibitor PD98059 to determine whether the stimulant effects of Rg1 on cell proliferation, the induction of IGF-IR and pS2, the functional transactivation of oestrogen receptor-alpha (ERalpha), as well as ERalpha phosphorylation are dependent on MAPK. The time-dependent responses of mitogen-activated protein kinase kinase (MEK) and extracellular signal-regulated protein kinase (ERK) to Rg1 in MCF-7 cells were studied. The responses of MEK phosphorylation to Rg1 in oestrogen receptor (ER)-negative HEK293 cells were also determined. The effects of Rg1 on cell proliferation and IGF-IR protein expression were studied in the presence of tyrosine kinase inhibitor genistein to elucidate the involvement of tyrosine kinase in mediating these effects. KEY RESULTS The oestrogenic effects of Rg1 in MCF-7 cells were abolished in the presence of PD98059. Rg1 could induce MEK protein expression and the phosphorylation level of MEK and ERK significantly in a time- and dose-dependent manner. Rg1 activated MEK phosphorylation in ER-negative HEK293 cells in a time- and dose-dependent manner. Rg1 induction of cell proliferation and IGF-IR protein expression was abolished by co-treatment with genistein. CONCLUSIONS AND IMPLICATIONS Taken together, these results show that the MAPK pathway is involved in mediating the oestrogen-like actions of Rg1 in MCF-7 cells and suggest that Rg1 may activate ERalpha via MEK/ERK in a ligand-independent manner.
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Affiliation(s)
- Wai-Sum Lau
- Central Laboratory of the Institute of Molecular Technology for Drug Discovery and Synthesis, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
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15
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Bratton MR, Frigo DE, Vigh-Conrad KA, Fan D, Wadsworth S, McLachlan JA, Burow ME. Organochlorine-mediated potentiation of the general coactivator p300 through p38 mitogen-activated protein kinase. Carcinogenesis 2008; 30:106-13. [PMID: 18791200 DOI: 10.1093/carcin/bgn213] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The activity of nuclear transcription factors is often regulated by specific kinase-signaling pathways. We have previously shown that the organochlorine pesticide dichlorodiphenyltrichloroethane (DDT) stimulates activator protein-1 activity through the p38 mitogen-activated protein kinase (MAPK). Here, we show that DDT and its metabolites also stimulate the transcriptional activity of cyclic adenosine monophosphate response element-binding protein and Elk1 and potentiate gene expression through cyclic adenosine monophosphate and hypoxia response elements. Because DDT stimulates gene expression through various transcription factors and hence multiple response elements, we hypothesized that p38 signaling targets a common shared transcriptional activator. Here, we demonstrate using both pharmacological and molecular techniques, the general coactivator p300 is phosphorylated and potentiated by the p38 MAPK signaling cascade. We further show that p38 directly phosphorylates p300 in its N-terminus. These results, together with our previous work, suggest that p38 stimulates downstream transcription factors in part by targeting the general coactivator p300.
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Affiliation(s)
- Melyssa R Bratton
- Department of Pharmacology, Tulane University Health Science Center, New Orleans, LA 70112, USA
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16
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Subramanian A, Mokbel K. The role of Herceptin in early breast cancer. INTERNATIONAL SEMINARS IN SURGICAL ONCOLOGY 2008; 5:9. [PMID: 18442393 PMCID: PMC2383915 DOI: 10.1186/1477-7800-5-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2008] [Accepted: 04/28/2008] [Indexed: 11/10/2022]
Abstract
Herceptin is widely regarded as the most important development in the treatment of breast cancer since Tamoxifen and the development of the multidisciplinary team (MDT). It is particularly exciting from an oncological polint of view as it represents success in the emerging field of specific targeted therapies to specific molecular abnormalities in tumour cells. This review will focus on the nature of the Her2 overexpression and the role of herceptin in the treatment of early breast cancer.
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17
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Bao J, Cao C, Zhang X, Jiang F, Nicosia SV, Bai W. Suppression of beta-amyloid precursor protein signaling into the nucleus by estrogens mediated through complex formation between the estrogen receptor and Fe65. Mol Cell Biol 2006; 27:1321-33. [PMID: 17130235 PMCID: PMC1800721 DOI: 10.1128/mcb.01280-06] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The C-terminal fragment of the beta-amyloid precursor protein produced after cleavage by gamma-secretase, namely, APPct or AICD, has been shown to form a multimeric complex with the adaptor protein Fe65 and to regulate transcription through the recruitment of the histone acetyltransferase Tip60. The present study shows that 17beta-estradiol inhibits the transcriptional and apoptotic activities of the APPct complex by a process involving the interaction of estrogen receptor alpha (ERalpha) with Fe65. ERalpha-Fe65 complexes were detected both in vitro and in the mouse brain, and recruitment of ERalpha to the promoter of an APPct target gene (KAI1) was demonstrated. Our studies reveal a novel mechanism of estrogen action, which may explain the well-known neuroprotective functions of estrogens as well as the complex role of this female hormone in the pathogenesis of neuronal degeneration diseases.
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Affiliation(s)
- Junying Bao
- Department of Pathology, University of South Florida College of Medicine, 12901 Bruce B. Downs Blvd., Tampa, FL 33612-4799, USA
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18
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Schiff R, Osborne CK. Endocrinology and hormone therapy in breast cancer: new insight into estrogen receptor-alpha function and its implication for endocrine therapy resistance in breast cancer. Breast Cancer Res 2005; 7:205-11. [PMID: 16168139 PMCID: PMC1242145 DOI: 10.1186/bcr1287] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Estrogen and its receptor (ER) are critical for development and progression of breast cancer. This pathway is targeted by endocrine therapies that either block ER functions or deplete ER's estrogen ligand. While endocrine therapies are very effective, de novo and acquired resistance are still common. Laboratory and clinical data now indicate that bidirectional molecular crosstalk between nuclear or membrane ER and growth factor receptor pathways such as HER2/neu is involved in endocrine resistance. Preclinical data suggest that blockade of selected growth factor receptor signaling can overcome this type of resistance, and this strategy is already being tested in clinical trials
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Affiliation(s)
- Rachel Schiff
- Breast Center, Baylor College of Medicine and The Methodist Hospital, Houston, Texas, USA.
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19
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Yang Y, Hou H, Haller EM, Nicosia SV, Bai W. Suppression of FOXO1 activity by FHL2 through SIRT1-mediated deacetylation. EMBO J 2005; 24:1021-32. [PMID: 15692560 PMCID: PMC554122 DOI: 10.1038/sj.emboj.7600570] [Citation(s) in RCA: 264] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2004] [Accepted: 01/07/2005] [Indexed: 11/09/2022] Open
Abstract
Forkhead box class O (FOXO) proteins are transcription factors that function downstream of the PTEN tumor suppressor and directly control the expression of genes involved in apoptosis, cell cycle progression, and stress responses. In the present study, we show that FOXO1 interacts with four and a half LIM 2 (FHL2) in prostate cancer cells. This interaction occurred in the nucleus and was enhanced by lysophosphatic acid. FHL2 decreased the transcriptional activity of FOXO1 and the expression of known FOXO target genes and inhibited FOXO1-induced apoptosis. Interestingly, SIRT1, a mammalian homolog of yeast Sir2, bound to and deacetylated FOXO1 and inhibited its transcriptional activity. FHL2 enhanced the interaction of FOXO1 and SIRT1 and the deacetylation of FOXO1 by Sirtuin-1 (SIRT1). Overall, our data show that FHL2 inhibits FOXO1 activity in prostate cancer cells by promoting the deacetylation of FOXO1 by SIRT1.
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Affiliation(s)
- Yonghua Yang
- Departments of Pathology and Interdisciplinary Oncology, University of South Florida College of Medicine and Programs of Molecular Oncology, Drug Discovery and Experimental Therapeutics, H Lee Moffitt Cancer Center, Tampa, FL, USA
| | - Huayan Hou
- Departments of Pathology and Interdisciplinary Oncology, University of South Florida College of Medicine and Programs of Molecular Oncology, Drug Discovery and Experimental Therapeutics, H Lee Moffitt Cancer Center, Tampa, FL, USA
| | - Edward M Haller
- Departments of Pathology and Interdisciplinary Oncology, University of South Florida College of Medicine and Programs of Molecular Oncology, Drug Discovery and Experimental Therapeutics, H Lee Moffitt Cancer Center, Tampa, FL, USA
| | - Santo V Nicosia
- Departments of Pathology and Interdisciplinary Oncology, University of South Florida College of Medicine and Programs of Molecular Oncology, Drug Discovery and Experimental Therapeutics, H Lee Moffitt Cancer Center, Tampa, FL, USA
| | - Wenlong Bai
- Departments of Pathology and Interdisciplinary Oncology, University of South Florida College of Medicine and Programs of Molecular Oncology, Drug Discovery and Experimental Therapeutics, H Lee Moffitt Cancer Center, Tampa, FL, USA
- Department of Pathology, University of South Florida, College of Medicine, 12901 Bruce B Downs Blvd, MDC 11, Tampa, FL 33612-4799, USA. Tel.: +1 813 974 0563; Fax: +1 813 974 5536; E-mail:
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20
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Jansen MS, Nagel SC, Miranda PJ, Lobenhofer EK, Afshari CA, McDonnell DP. Short-chain fatty acids enhance nuclear receptor activity through mitogen-activated protein kinase activation and histone deacetylase inhibition. Proc Natl Acad Sci U S A 2004; 101:7199-204. [PMID: 15103026 PMCID: PMC406489 DOI: 10.1073/pnas.0402014101] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
In this study, we demonstrate that the pervasive xenobiotic methoxyacetic acid and the commonly prescribed anticonvulsant valproic acid, both short-chain fatty acids (SCFAs), dramatically increase cellular sensitivity to estrogens, progestins, and other nuclear hormone receptor ligands. These compounds do not mimic endogenous hormones but rather act to enhance the transcriptional efficacy of ligand activated nuclear hormone receptors by up to 8-fold in vitro and in vivo. Detailed characterization of their mode of action revealed that these SCFAs function as both activators of p42/p44 mitogen-activated protein kinase and as inhibitors of histone deacetylases at doses that parallel known exposure levels. Our results define a class of compounds that possess a dual mechanism of action and function as hormone sensitizers. These findings prompt an evaluation of previously unrecognized drug-drug interactions in women who are administered exogenous hormones while exposed to certain xenobiotic SCFAs. Furthermore, our study highlights the need to structure future screening programs to identify additional hormone sensitizers.
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Affiliation(s)
- Michelle S Jansen
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA
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21
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Watanabe T, Jono H, Han J, Lim DJ, Li JD. Synergistic activation of NF-kappaB by nontypeable Haemophilus influenzae and tumor necrosis factor alpha. Proc Natl Acad Sci U S A 2004; 101:3563-8. [PMID: 14993593 PMCID: PMC373502 DOI: 10.1073/pnas.0400557101] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2003] [Indexed: 11/18/2022] Open
Abstract
Nontypeable Haemophilus influenzae (NTHi) is an important human pathogen causing otitis media in children and exacerbation of chronic obstructive pulmonary disease in adults. Like most other bacterial infections, NTHi infections are also characterized by inflammation, which is mainly mediated by cytokines and chemokines such as tumor necrosis factor alpha (TNF-alpha). Among a variety of transcription regulators, NF-kappaB has been shown to play a critical role in regulating the expression of large numbers of genes encoding inflammatory mediators. In review of the current studies on NF-kappaB regulation, most of them have focused on investigating how NF-kappaB is activated by a single inducer at a time. However, in bacteria-induced inflammation in vivo, multiple inducers including both exogenous and endogenous mediators are present simultaneously. A key issue that has yet to be addressed is whether the exogenous inducers such as NTHi and the endogenous factors such as TNF-alpha activate NF-kappaB in a synergistic manner. We show that NTHi and TNF-alpha, when present together, synergistically induce NF-kappaB activation via two distinct signaling pathways: NF-kappaB translocation-dependent and -independent pathways. The NF-kappaB translocation-dependent pathway involves NF-kappaB-inducing kinase-IkappaB kinase beta/gamma-dependent phosphorylation and degradation of IkappaBalpha, whereas the NF-kappaB translocation-independent pathway involves mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase kinase kinase 1-dependent activation of MAPK kinase 3/6-p38 MAPK pathway. In addition, the same signaling pathways are also involved in synergistic induction of TNF-alpha, IL-1beta, and IL-8. These studies should deepen our understanding of the molecular mechanisms underlying the combinatorial regulation of inflammation and lead to development of therapeutic strategies for NTHi-induced infections.
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Affiliation(s)
- Takahiro Watanabe
- Gonda Department of Cell and Molecular Biology, House Ear Institute, University of Southern California, Los Angeles, CA 90057, USA
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22
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Kolluri SK, Bruey-Sedano N, Cao X, Lin B, Lin F, Han YH, Dawson MI, Zhang XK. Mitogenic effect of orphan receptor TR3 and its regulation by MEKK1 in lung cancer cells. Mol Cell Biol 2003; 23:8651-67. [PMID: 14612408 PMCID: PMC262666 DOI: 10.1128/mcb.23.23.8651-8667.2003] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
TR3, also known as NGFI-B or nur77, is an immediate-early response gene and an orphan member of the steroid/thyroid/retinoid receptor superfamily. We previously reported that TR3 expression was induced by apoptotic stimuli and was required for their apoptotic effect in lung cancer cells. Here, we present evidence that TR3 was also induced by epidermal growth factor (EGF) and serum and was required for their mitogenic effect in lung cancer cells. Ectopic expression of TR3 in both H460 and Calu-6 lung cancer cell lines promoted their cell cycle progression and BrdU incorporation, while inhibition of TR3 expression by the small interfering RNA approach suppressed the mitogenic effect of EGF and serum. Analysis of TR3 mutants showed that both TR3 DNA binding and transactivation were required for its mitogenic effect. In contrast, they were dispensable for its apoptotic activity. Furthermore, confocal microscopy analysis demonstrated that TR3 functioned in the nucleus to induce cell proliferation, whereas it acted on mitochondria to induce apoptosis. In examining the signaling that regulates the mitogenic function of TR3, we observed that coexpression of constitutive-active MEKK1 inhibited TR3 transcriptional activity and TR3-induced proliferation. The inhibitory effect of MEKK1 was mediated through activation of Jun N-terminal kinase, which efficiently phosphorylated TR3, resulting in loss of its DNA binding. Together, our results demonstrate that TR3 is capable of inducing both proliferation and apoptosis in the same cells depending on the stimuli and its cellular localization.
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23
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Li P, Lee H, Guo S, Unterman TG, Jenster G, Bai W. AKT-independent protection of prostate cancer cells from apoptosis mediated through complex formation between the androgen receptor and FKHR. Mol Cell Biol 2003; 23:104-18. [PMID: 12482965 PMCID: PMC140652 DOI: 10.1128/mcb.23.1.104-118.2003] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recent studies suggested that the protection of cell apoptosis by AKT involves phosphorylation and inhibition of FKHR and related FOXO forkhead transcription factors and that androgens provide an AKT-independent cell survival signal in prostate cancer cells. Here, we report receptor-dependent repression of FKHR function by androgens in prostate cancer cells. Transcriptional analysis demonstrated that activation of the androgen receptor caused an inhibition of both wild-type FKHR and a mutant in which all three known AKT sites were mutated to alanines, showing that the repression is AKT independent. In vivo and in vitro coprecipitation studies demonstrated that the repression is mediated through protein-protein interaction between FKHR and the androgen receptor. Mapping analysis localized the interacting domains to the carboxyl terminus between amino acids 350 and 655 of FKHR and to the amino-terminal A/B region and the ligand binding domain of the receptor. Further analysis demonstrated that the activated androgen receptor blocked FKHR's DNA binding activity and impaired its ability to induce Fas ligand expression and prostate cancer cell apoptosis and cell cycle arrest. These studies identify a new mechanism for androgen-mediated prostate cancer cell survival that appears to be independent of the activity of the receptor on androgen response element-mediated transcription and establish FKHR and related FOXO forkhead proteins as important nuclear targets for both AKT-dependent and -independent survival signals in prostate cancer cells.
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Affiliation(s)
- Pengfei Li
- Department of Pathology, University of South Florida College of Medicine, and Program of Molecular Oncology and Drug Discovery, H. Lee Moffitt Cancer Center, Tampa 33612-4799, USA
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24
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Driggers PH, Segars JH. Estrogen action and cytoplasmic signaling pathways. Part II: the role of growth factors and phosphorylation in estrogen signaling. Trends Endocrinol Metab 2002; 13:422-7. [PMID: 12431838 PMCID: PMC4152897 DOI: 10.1016/s1043-2760(02)00634-3] [Citation(s) in RCA: 185] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
In recent years, distinct signaling pathways involving specific complexes of cytoplasmic proteins have been shown to orchestrate estrogen action. These pathways might supplement or augment genomic effects of estrogen that are attributable to transcriptional activation by liganded receptor. Signals might be transduced through phosphorylation of the estrogen receptors (ERs), or indirectly through effects upon transcriptional coactivators or cell receptors. Estrogen signaling is coupled to growth factor signaling with feedback mechanisms directly impacting function of growth factor receptors. These signaling pathways regulate important physiological processes, such as cell growth and apoptosis. Here, we focus on cytoplasmic signaling pathways leading to activation of ERs.
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Affiliation(s)
- Paul H Driggers
- Dept of Obstetrics and Gynecology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Rd, Bethesda, MD, USA.
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25
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Lee H, Bai W. Regulation of estrogen receptor nuclear export by ligand-induced and p38-mediated receptor phosphorylation. Mol Cell Biol 2002; 22:5835-45. [PMID: 12138194 PMCID: PMC133965 DOI: 10.1128/mcb.22.16.5835-5845.2002] [Citation(s) in RCA: 150] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Estrogen receptors are phosphoproteins which can be activated by ligands, kinase activators, or phosphatase inhibitors. Our previous study showed that p38 mitogen-activated protein kinase was involved in estrogen receptor activation by estrogens and MEKK1. Here, we report estrogen receptor-dependent p38 activation by estrogens in endometrial adenocarcinoma cells and in vitro and in vivo phosphorylation of the estrogen receptor alpha mediated through p38. The phosphorylation site was identified as threonine-311 (Thr(311)), located in helix 1 of the hormone-binding domain. The mutation of threonine-311 to alanine did not affect estrogen binding of the receptor but compromised its interaction with coactivators. Suppression of p38 activity or mutation of the site inhibited the estrogen-induced receptor nuclear localization as well as its transcriptional activation by estrogens and MEKK1. The inhibition of the p38 signal pathway by a specific chemical inhibitor blocked the biological activities of estrogens in regulating endogenous gene expression as well as endometrial cancer cell growth. Our studies demonstrate the role of estrogen receptor phosphorylation induced by the natural ligand in estrogen receptor's cellular distribution and its significant contribution to the growth-stimulating activity of estrogens in endometrial cancer cells.
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Affiliation(s)
- Heehyoung Lee
- Department of Pathology, University of South Florida College of Medicine, and Program of Molecular Oncology and Drug Discovery, H. Lee Moffitt Cancer Center, Tampa, Florida 33612-4799, USA
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26
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Driggers PH, Segars JH, Rubino DM. The proto-oncoprotein Brx activates estrogen receptor beta by a p38 mitogen-activated protein kinase pathway. J Biol Chem 2001; 276:46792-7. [PMID: 11579095 PMCID: PMC4152864 DOI: 10.1074/jbc.m106927200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The estrogen receptors (ERs) are ligand-inducible transcription factors that play key roles in the control of growth and differentiation in reproductive tissues. We showed that the novel Dbl family proto-oncoprotein Brx enhances ligand-dependent activity of ERalpha via a Cdc42-dependent pathway. Brx also significantly enhances ligand-dependent activity of ERbeta. This enhancement is not affected by inhibition of p44/42 mitogen-activated protein kinase (MAPK) activation by PD98059. However, addition of the p38 MAPK inhibitor SB202190 abrogates the enhancement of ERbeta activity by Brx, showing that p38 MAPK activity is required for the enhancement of ERbeta function by Brx. In COS-7 cells, transfection of Brx leads to activation of endogenous p38 MAPK activity. Co-expression of the beta2 isoform of human p38 MAPK and a constitutively active form of the p38 MAPK kinase MKK6 (MKK6-EE) synergistically augments ligand-dependent activity of ERbeta. Our findings suggest that p38 MAPKs may be important regulators of ERbeta activity.
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Affiliation(s)
- P H Driggers
- Department of Obstetrics and Gynecology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814, USA.
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27
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Schlegel A, Wang C, Pestell RG, Lisanti MP. Ligand-independent activation of oestrogen receptor alpha by caveolin-1. Biochem J 2001; 359:203-10. [PMID: 11563984 PMCID: PMC1222136 DOI: 10.1042/0264-6021:3590203] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Expression of caveolin-1 in the human mammary adenocarcinoma cell line MCF-7 causes ligand-independent concentration of oestrogen receptor alpha (ERalpha) in the nucleus, and potentiates ligand-independent and ligand-dependent transcription from an oestrogen response element-driven reporter gene. Furthermore, caveolin-1 co-immunoprecipitates with ERalpha [Schlegel, Wang, Katzenellenbogen, Pestell and Lisanti (1999) J. Biol. Chem. 274, 33551-33556]. In the present study we show that caveolin-1 binds directly to ERalpha. This interaction is mediated by residues 82-101 of caveolin-1 (i.e. the caveolin scaffolding domain) and residues 1-282 of ERalpha. The caveolin-binding domain of ERalpha includes the ligand-independent transactivation domain, activation function (AF)-1, but lacks the hormone-binding domain and the ligand-gated transactivation domain, AF-2. In co-transfection studies, caveolin-1 potentiates the transcriptional activation of ERalpha(1-282), a truncation mutant that has intact AF-1 and DNA-binding domains. Since AF-1 activity is regulated largely by phosphorylation we determined that co-expression with caveolin-1 increased the basal phosphorylation of ERalpha(1-282), but blocked the epidermal growth factor-dependent increase in phosphorylation. Indeed, caveolin-1 interacted with and potentiated the transactivation of an ERalpha mutant that cannot be phosphorylated by extracellular signal-regulated kinase (ERK)1/2 [ERalpha(Ser(118)-->Ala)]. Thus caveolin-1 is a novel ERalpha regulator that drives ERK1/2-independent phosphorylation and activation of AF-1.
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Affiliation(s)
- A Schlegel
- Department of Molecular Pharmacology, The Albert Einstein Cancer Centre, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
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28
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Shen T, Horwitz KB, Lange CA. Transcriptional hyperactivity of human progesterone receptors is coupled to their ligand-dependent down-regulation by mitogen-activated protein kinase-dependent phosphorylation of serine 294. Mol Cell Biol 2001; 21:6122-31. [PMID: 11509655 PMCID: PMC87329 DOI: 10.1128/mcb.21.18.6122-6131.2001] [Citation(s) in RCA: 163] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Breast cancers often exhibit elevated expression of tyrosine kinase growth factor receptors; these pathways influence breast cancer cell growth in part by targeting steroid hormone receptors, including progesterone receptors (PR). To mimic activation of molecules downstream of growth factor-initiated signaling pathways, we overexpressed mitogen-activated protein kinase (MAPK; also known as extracellular signal-regulated kinase) kinase kinase 1 (MEKK1) in T47D human breast cancer cells expressing the B isoform of PR. MEKK1 is a strong activator of p42 and p44 MAPKs. MEKK1 expression increased progestin-mediated transcription 8- to 10-fold above normal PR-driven transcription levels. This was dependent on the presence of a progesterone response element and functional PR. PR protein levels were unchanged by MEKK1 alone but were extensively down-regulated by MEKK1 plus the progestin R5020. MEKK1 expression resulted in phosphorylation of PR on Ser294, a MAPK consensus site known to mediate ligand-dependent PR degradation. MEK inhibitors blocked phosphorylation of Ser294 and attenuated PR transcriptional hyperactivity in response to MEKK1 plus R5020; stabilization of PR by inhibition of the 26S proteasome produced similar results. T47D cells stably expressing mutant S294A PR, in which serine 294 is replaced by alanine, fail to undergo ligand-dependent down-regulation and are resistant to MEKK1-plus-R5020-induced transcriptional synergy but respond to progestins alone. Similarly, c-myc protein levels are synergistically increased by epidermal growth factor and R5020 in cells expressing wild-type PR, but not S294A PR. Thus, highly stable mutant PR are functional in response to progestins but are incapable of cross talk with MAPK-driven pathways. These studies demonstrate a paradoxical coupling between steroid receptor down-regulation and transcriptional hyperactivity. They also suggest a link between phosphorylation of PR by MAPKs in response to peptide growth factor signaling and steroid hormone control of breast cancer cell growth.
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Affiliation(s)
- T Shen
- Department of Medicine, The Molecular Biology Program, and The Colorado Cancer Center, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA
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