1
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Parl FF, Crooke PS, Plummer WD, Dupont WD. Genomic-Epidemiologic Evidence That Estrogens Promote Breast Cancer Development. Cancer Epidemiol Biomarkers Prev 2018; 27:899-907. [PMID: 29789325 DOI: 10.1158/1055-9965.epi-17-1174] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 02/23/2018] [Accepted: 05/14/2018] [Indexed: 12/21/2022] Open
Abstract
Background: Estrogens are a prime risk factor for breast cancer, yet their causal relation to tumor formation remains uncertain. A recent study of 560 breast cancers identified 82 genes with 916 point mutations as drivers in the genesis of this malignancy. Because estrogens play a major role in breast cancer development and are also known to regulate the expression of numerous genes, we hypothesize that the 82 driver genes are likely to be influenced by estrogens, such as 17ß-estradiol (E2), and the estrogen receptor ESR1 (ERα). Because different types of tumors are characterized by unique sets of cancer driver genes, we also argue that the fraction of driver genes regulated by E2-ESR1 is lower in malignancies not associated with estrogens, e.g., acute myeloid leukemia (AML).Methods: We performed a literature search of each driver gene to determine its E2-ESR1 regulation.Results: Fifty-three of the 82 driver genes (64.6%) identified in breast cancers showed evidence of E2-ESR1 regulation. In contrast, only 19 of 54 mutated driver genes (35.2%) identified in AML were linked to E2-ESR1. Among the 916 driver mutations found in breast cancers, 813 (88.8%) were linked to E2-ESR1 compared with 2,046 of 3,833 in AML (53.4%).Conclusions: Risk assessment revealed that mutations in estrogen-regulated genes are much more likely to be associated with elevated breast cancer risk, while mutations in unregulated genes are more likely to be associated with AML.Impact: These results increase the plausibility that estrogens promote breast cancer development. Cancer Epidemiol Biomarkers Prev; 27(8); 899-907. ©2018 AACR.
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Affiliation(s)
- Fritz F Parl
- Department of Pathology, Microbiology and Immunology, Vanderbilt University, Nashville, Tennessee.
| | - Philip S Crooke
- Department of Mathematics, Vanderbilt University, Nashville, Tennessee
| | - W Dale Plummer
- Department of Health Policy, Vanderbilt University, Nashville, Tennessee
| | - William D Dupont
- Department of Health Policy, Vanderbilt University, Nashville, Tennessee
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2
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Xu BL, Zhao QZ, Gao XY, Hou GJ. Effect of estradiol and bisphenol A on human hepatoblastoma cell viability and telomerase activity. ACTA ACUST UNITED AC 2015; 48:1004-9. [PMID: 26397976 PMCID: PMC4671527 DOI: 10.1590/1414-431x20154400] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 04/28/2015] [Indexed: 12/05/2022]
Abstract
Sex hormones from environmental and physiological sources might play a major role in
the pathogenesis of hepatoblastoma in children. This study investigated the effects
of estradiol and bisphenol A on the proliferation and telomerase activity of human
hepatoblastoma HepG2 cells. The cells were divided into 6 treatment groups: control,
bisphenol A, estradiol, anti-estrogen ICI 182,780 (hereinafter ICI), bisphenol A+ICI,
and estradiol+ICI. Cell proliferation was measured based on average absorbance using
the Cell Counting-8 assay. The cell cycle distribution and apoptotic index were
determined by flow cytometry. Telomerase activity was detected by polymerase chain
reaction and a telomeric repeat amplification protocol assay. A higher cell density
was observed in bisphenol A (P<0.01) and estradiol (P<0.05) groups compared
with the control group. Cell numbers in S and G2/M phases after treatment for 48 h
were higher (P<0.05), while the apoptotic index was lower (P<0.05) and
telomerase activities at 48 and 72 h (P<0.05) were higher in these groups than in
the control group. The cell density was also higher in bisphenol A+ICI (P<0.01)
and estradiol+ICI (P<0.05) groups compared with the ICI group. Furthermore, cell
numbers were increased in S and G2/M phases (P<0.05), while the apoptotic index
was lower (P<0.05) and telomerase activities at 48 and 72 h were higher
(P<0.05) in these groups than in the ICI group. Therefore, bisphenol A and
estradiol promote HepG2 cell proliferation in vitro by inhibition of
apoptosis and stimulation of telomerase activity via an estrogen receptor-dependent
pathway.
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Affiliation(s)
- B L Xu
- Children's Hospital of Zhengzhou, Zhengzhou, China
| | - Q Z Zhao
- Basic Medical College, Zhengzhou University, Zhengzhou, China
| | - X Y Gao
- Children's Hospital of Zhengzhou, Zhengzhou, China
| | - G J Hou
- Children's Hospital of Zhengzhou, Zhengzhou, China
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3
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Yang J, Fuller PJ, Morgan J, Shibata H, Clyne CD, Young MJ. GEMIN4 functions as a coregulator of the mineralocorticoid receptor. J Mol Endocrinol 2015; 54:149-60. [PMID: 25555524 DOI: 10.1530/jme-14-0078] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The mineralocorticoid receptor (MR) is a member of the nuclear receptor superfamily. Pathological activation of the MR causes cardiac fibrosis and heart failure, but clinical use of MR antagonists is limited by the renal side effect of hyperkalemia. Coregulator proteins are known to be critical for nuclear receptor-mediated gene expression. Identification of coregulators, which mediate MR activity in a tissue-specific manner, may allow for the development of novel tissue-selective MR modulators that confer cardiac protection without adverse renal effects. Our earlier studies identified a consensus motif among MR-interacting peptides, MPxLxxLL. Gem (nuclear organelle)-associated protein 4 (GEMIN4) is one of the proteins that contain this motif. Transient transfection experiments in HEK293 and H9c2 cells demonstrated that GEMIN4 repressed agonist-induced MR transactivation in a cell-specific manner. Furthermore, overexpression of GEMIN4 significantly decreased, while knockdown of GEMIN4 increased, the mRNA expression of specific endogenous MR target genes. A physical interaction between GEMIN4 and MR is suggested by their nuclear co-localization upon agonist treatment. These findings indicate that GEMIN4 functions as a novel coregulator of the MR.
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Affiliation(s)
- Jun Yang
- MIMR-PHI InstitutePO Box 5152, Clayton, Victoria 3168, AustraliaDepartment of MedicineMonash University, Clayton, Victoria 3168, AustraliaDepartment of EndocrinologyMetabolism, Rheumatology and Nephrology, Oita University, Yufu 879-5593, Japan MIMR-PHI InstitutePO Box 5152, Clayton, Victoria 3168, AustraliaDepartment of MedicineMonash University, Clayton, Victoria 3168, AustraliaDepartment of EndocrinologyMetabolism, Rheumatology and Nephrology, Oita University, Yufu 879-5593, Japan
| | - Peter J Fuller
- MIMR-PHI InstitutePO Box 5152, Clayton, Victoria 3168, AustraliaDepartment of MedicineMonash University, Clayton, Victoria 3168, AustraliaDepartment of EndocrinologyMetabolism, Rheumatology and Nephrology, Oita University, Yufu 879-5593, Japan MIMR-PHI InstitutePO Box 5152, Clayton, Victoria 3168, AustraliaDepartment of MedicineMonash University, Clayton, Victoria 3168, AustraliaDepartment of EndocrinologyMetabolism, Rheumatology and Nephrology, Oita University, Yufu 879-5593, Japan
| | - James Morgan
- MIMR-PHI InstitutePO Box 5152, Clayton, Victoria 3168, AustraliaDepartment of MedicineMonash University, Clayton, Victoria 3168, AustraliaDepartment of EndocrinologyMetabolism, Rheumatology and Nephrology, Oita University, Yufu 879-5593, Japan
| | - Hirotaka Shibata
- MIMR-PHI InstitutePO Box 5152, Clayton, Victoria 3168, AustraliaDepartment of MedicineMonash University, Clayton, Victoria 3168, AustraliaDepartment of EndocrinologyMetabolism, Rheumatology and Nephrology, Oita University, Yufu 879-5593, Japan
| | - Colin D Clyne
- MIMR-PHI InstitutePO Box 5152, Clayton, Victoria 3168, AustraliaDepartment of MedicineMonash University, Clayton, Victoria 3168, AustraliaDepartment of EndocrinologyMetabolism, Rheumatology and Nephrology, Oita University, Yufu 879-5593, Japan
| | - Morag J Young
- MIMR-PHI InstitutePO Box 5152, Clayton, Victoria 3168, AustraliaDepartment of MedicineMonash University, Clayton, Victoria 3168, AustraliaDepartment of EndocrinologyMetabolism, Rheumatology and Nephrology, Oita University, Yufu 879-5593, Japan MIMR-PHI InstitutePO Box 5152, Clayton, Victoria 3168, AustraliaDepartment of MedicineMonash University, Clayton, Victoria 3168, AustraliaDepartment of EndocrinologyMetabolism, Rheumatology and Nephrology, Oita University, Yufu 879-5593, Japan
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4
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Kharbanda A, Rajabi H, Jin C, Raina D, Kufe D. Oncogenic MUC1-C promotes tamoxifen resistance in human breast cancer. Mol Cancer Res 2013; 11:714-23. [PMID: 23538857 DOI: 10.1158/1541-7786.mcr-12-0668] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Tamoxifen resistance of estrogen receptor-positive (ER+) breast cancer cells has been linked in part to activation of receptor tyrosine kinases, such as HER2, and the PI3K-AKT pathway. Mucin 1 (MUC1) is aberrantly overexpressed in about 90% of human breast cancers, and the oncogenic MUC1-C subunit is associated with ERα. The present studies using HER2 overexpressing BT-474 breast cancer cells, which are constitutively resistant to tamoxifen, demonstrate that silencing MUC1-C is associated with (i) downregulation of p-HER2 and (ii) sensitivity to tamoxifen-induced growth inhibition and loss of clonogenic survival. In contrast, overexpression of MUC1-C in tamoxifen-sensitive MCF-7 breast cancer cells resulted in upregulation of p-AKT and tamoxifen resistance. We show that MUC1-C forms complexes with ERα on the estrogen-responsive promoter of Rab31 and that MUC1-C blocks tamoxifen-induced decreases in ERα occupancy. MUC1-C also attenuated tamoxifen-induced decreases in (i) recruitment of the coactivator CREB binding protein, (ii) Rab31 promoter activation, and (iii) Rab31 mRNA and protein levels. The importance of MUC1-C is further supported by the demonstration that targeting MUC1-C with the cell-penetrating peptide inhibitor, GO-203, sensitized tamoxifen-resistant cells to tamoxifen treatment. Moreover, we show that targeting MUC1-C in combination with tamoxifen is highly synergistic in the treatment of tamoxifen-resistant breast cancer cells. Combined, these findings indicate that MUC1-C contributes to tamoxifen resistance.
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Affiliation(s)
- Akriti Kharbanda
- Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02215, USA
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5
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Jiang XR, Wang P, Smith CL, Zhu BT. Synthesis of novel estrogen receptor antagonists using metal-catalyzed coupling reactions and characterization of their biological activity. J Med Chem 2013; 56:2779-90. [PMID: 23448346 DOI: 10.1021/jm3013773] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Estrogen receptor (ER) antagonists are valuable in the treatment of ER-positive human breast cancer. In this study, we designed and synthesized nine new derivatives of 17β-estradiol (E2) with a bulky side chain attached to its C-7α position, and determined their ER antagonistic activity using in vitro bioassays. Four of the derivatives showed a strong inhibition of ERα transactivation activity in a luciferase reporter assay and blocked ERα interactions with coactivators. Similarly, these derivatives also strongly inhibited the growth of the ERα-positive human breast cancer cells. Computational docking analysis was conducted to model the interaction of these antagonists with the human ERα and showed that they could tightly bind to the ERα in a manner similar to that of ICI-182,780, a pure ER antagonist. These results provide an example that attachment of a bulky side chain to the C-7α position of E2 can produce ER antagonists with ER affinity comparable to that of ICI-182,780.
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Affiliation(s)
- Xiang-Rong Jiang
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, Kansas 66160, United States
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6
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Hoffman KL, Foster EA, Smith CL. The terminal substituents of 7α, 6-hexanyl derivatives of estradiol determine their selective estrogen receptor modulator versus agonist activities. Steroids 2012; 77:496-503. [PMID: 22326682 PMCID: PMC3303951 DOI: 10.1016/j.steroids.2012.01.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Revised: 01/10/2012] [Accepted: 01/11/2012] [Indexed: 02/07/2023]
Abstract
Pure antiestrogens were clinically developed as alternative therapies for estrogen receptor (ER) positive breast cancers. Unlike the selective estrogen receptor modulators (SERMs), these antiestrogens are devoid of tissue-specific ER agonist activity. Many of these compounds are steroidal in nature, containing an estradiol (E2) structural core with long alkyl side chains at the C-7α position. Two novel 7α-substituted E2 derivatives were evaluated that retain high binding affinity for ER. Compared to known pure antiestrogens, these compounds, referred to as compound 13 (C13) and C14, contain shorter 7α alkyl side chains and differ only in their terminal substituent: a hydroxyl moiety versus a benzyloxy group, respectively. Herein we assessed the effects of these compounds on ER transcriptional activity and report that despite their similar overall structure, C13 and C14 produce distinct cell type-specific responses. Of note, C13 functions as a mixed agonist/antagonist in Hela cells, inducing only weak ER transcriptional activity while preventing coactivator recruitment and stabilizing ER expression. However, this compound effectively stimulates ER activity in MCF-7 cells, does not increase ER levels and promotes cell proliferation on par with E2. Conversely, C14 stimulates transcriptional activity in both cell types and enhances ER-coactivator interactions. The activities of both compounds were inhibited by the pure antiestrogen ICI 182,780. Taken together, these results reveal that C13 is a SERM while C14 is an ER agonist, and indicate that the terminal modification of the C-7α hexanyl side chain of these estradiol derivatives is an important determinant of the biocharacter of these ER ligands.
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Affiliation(s)
- Kristi L. Hoffman
- Program in Translational Biology & Molecular Medicine, Baylor College of Medicine, Houston, TX
- Department of Molecular & Cellular Biology, Baylor College of Medicine, Houston, TX
| | - Estrella A. Foster
- Department of Molecular & Cellular Biology, Baylor College of Medicine, Houston, TX
| | - Carolyn L. Smith
- Program in Translational Biology & Molecular Medicine, Baylor College of Medicine, Houston, TX
- Department of Molecular & Cellular Biology, Baylor College of Medicine, Houston, TX
- Scott Department of Urology, Baylor College of Medicine, Houston, TX
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7
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Anorexia nervosa and estrogen: Current status of the hypothesis. Neurosci Biobehav Rev 2010; 34:1195-200. [DOI: 10.1016/j.neubiorev.2010.01.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 01/28/2010] [Accepted: 01/29/2010] [Indexed: 01/25/2023]
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8
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Mohler ML, Bohl CE, Narayanan R, He Y, Hwang DJ, Dalton JT, Miller DD. Nonsteroidal Tissue‐Selective Androgen Receptor Modulators. ACTA ACUST UNITED AC 2008. [DOI: 10.1002/9783527623297.ch8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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9
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Higashimoto K, Kuhn P, Desai D, Cheng X, Xu W. Phosphorylation-mediated inactivation of coactivator-associated arginine methyltransferase 1. Proc Natl Acad Sci U S A 2007; 104:12318-23. [PMID: 17640894 PMCID: PMC1941467 DOI: 10.1073/pnas.0610792104] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Multiple protein arginine methyltransferases are involved in transcriptional activation of nuclear receptors. Coactivator-associated arginine methyltransferase 1 (CARM1)-mediated histone methylation has been shown to activate nuclear receptor-dependent transcription; however, little is known about the regulation of its enzymatic activity. Here, we report that the methyltransferase activity of CARM1 is negatively regulated through phosphorylation at a conserved serine residue. When the serine residue is mutated to glutamic acid, which mimics the phosphorylated serine residue, the mutant CARM1 exhibits diminished ability to bind the methyl donor adenosylmethionine and diminished histone methylation activity. Moreover, such mutation leads to the inhibition of CARM1 transactivation of estrogen receptor-dependent transcription. Our results provide an example for the regulation of protein arginine methyltransferase activity by phosphorylation. As CARM1 is a potent transcriptional coactivator of estrogen receptor, our results suggest that phosphorylation of CARM1 serves as a unique mechanism for inactivating CARM1-regulated estrogen-dependent gene expression.
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Affiliation(s)
- Ken Higashimoto
- *McArdle Laboratory for Cancer Research, University of Wisconsin, 1400 University Avenue, Madison, WI 53706; and
| | - Peter Kuhn
- *McArdle Laboratory for Cancer Research, University of Wisconsin, 1400 University Avenue, Madison, WI 53706; and
| | - Dhaval Desai
- *McArdle Laboratory for Cancer Research, University of Wisconsin, 1400 University Avenue, Madison, WI 53706; and
| | - Xiaodong Cheng
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road, Atlanta, GA 30322
| | - Wei Xu
- *McArdle Laboratory for Cancer Research, University of Wisconsin, 1400 University Avenue, Madison, WI 53706; and
- To whom correspondence should be addressed. E-mail:
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10
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Jaber BM, Gao T, Huang L, Karmakar S, Smith CL. The pure estrogen receptor antagonist ICI 182,780 promotes a novel interaction of estrogen receptor-alpha with the 3',5'-cyclic adenosine monophosphate response element-binding protein-binding protein/p300 coactivators. Mol Endocrinol 2006; 20:2695-710. [PMID: 16840538 DOI: 10.1210/me.2005-0218] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [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) is a member of the nuclear receptor superfamily of ligand-activated transcription factors. Abundant evidence demonstrates that ERalpha agonists promote, whereas antagonists inhibit, receptor binding to coactivators. In this report we demonstrate that binding of the ICI 182,780 (ICI) pure antiestrogen to ERalpha promotes its interaction with the cAMP response element-binding protein-binding protein (CBP)/p300 but not the p160 family of coactivators, demonstrating the specificity of this interaction. Amino acid mutations within the coactivator binding surface of the ERalpha ligand-binding domain revealed that CBP binds to this region of the ICI-liganded receptor. The carboxy-terminal cysteine-histidine rich domain 3 of CBP, rather than its amino-terminal nuclear interacting domain, shown previously to mediate agonist-dependent interactions of CBP with nuclear receptors, is required for binding to ICI-liganded ERalpha. Chromatin immunoprecipitation assays revealed that ICI but not the partial agonist/antagonist 4-hydroxytamoxifen is able to recruit CBP to the pS2 promoter, and this distinguishes ICI from this class of antiestrogens. Chromatin immunoprecipitation assays for pS2 and cytochrome P450 1B1 promoter regions revealed that ICI-dependent recruitment of CBP, but not receptor, to ERalpha targets is gene specific. ICI treatment did not recruit the steroid receptor coactivator 1 to the pS2 promoter, and it failed to induce the expression of this gene. Taken together, these data indicate that recruitment of the CBP coactivator/cointegrator without steroid receptor coactivator 1 to ERalpha is insufficient to promote transcription of ERalpha target genes.
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Affiliation(s)
- Basem M Jaber
- Molecular and Cellular Biology, One Baylor Plaza, Houston, Texas 77030, USA
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11
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García-Becerra R, Borja-Cacho E, Cooney AJ, Smith CL, Lemus AE, Pérez-Palacios G, Larrea F. Synthetic 19-nortestosterone derivatives as estrogen receptor alpha subtype-selective ligands induce similar receptor conformational changes and steroid receptor coactivator recruitment than natural estrogens. J Steroid Biochem Mol Biol 2006; 99:108-14. [PMID: 16616843 DOI: 10.1016/j.jsbmb.2006.01.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2005] [Accepted: 01/09/2006] [Indexed: 02/07/2023]
Abstract
The binding of estradiol (E(2)) to estrogen receptors (ER) is followed by conformational changes resulting in coactivator or corepressor recruitment that influences gene transcription. A series of synthetic A-ring reduced 19-nortestosterone-derived progestins has the capacity to selectively bind and activate transcription through the ERalpha. Herein, the molecular mechanisms involved in ER subtype-selective interactions of these compounds as assessed by their effects upon both ERalpha and ERbeta structural conformation and their ability to induce recruitment of steroid receptor coactivator-1 (SRC-1) to ERalpha were investigated. The results demonstrated that all synthetic A-ring 3beta,5alpha-tetrahydro-reduced derivatives of 19-nortestosterone induced an ERalpha trypsin digestion pattern similar to that seen with E(2), without effects upon ERbeta. In addition, these compounds had the ability to recruit SRC-1 to the ligand-binding domain of ERalpha similar to E(2). Our data indicate that A-ring 3beta,5alpha-tetrahydro-reduced 19-nortestosterone-derived progestins behave as selective ERalpha agonists with ligand-receptor structural and functional responses similar to those induced with natural E(2).
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Affiliation(s)
- Rocio García-Becerra
- Department of Reproductive Biology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Vasco de Quiroga No. 15, Mexico City 14000, Mexico
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12
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Zheng FF, Wu RC, Smith CL, O'Malley BW. Rapid estrogen-induced phosphorylation of the SRC-3 coactivator occurs in an extranuclear complex containing estrogen receptor. Mol Cell Biol 2005; 25:8273-84. [PMID: 16135815 PMCID: PMC1234335 DOI: 10.1128/mcb.25.18.8273-8284.2005] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2005] [Revised: 05/29/2005] [Accepted: 06/30/2005] [Indexed: 02/07/2023] Open
Abstract
SRC-3/AIB1/ACTR/pCIP/RAC3/TRAM1 is a primary transcriptional coregulator for estrogen receptor (ER). Six SRC-3 phosphorylation sites have been identified, and these can be induced by steroids, cytokines, and growth factors, involving multiple kinase signaling pathways. Using phosphospecific antibodies for six phosphorylation sites, we investigated the mechanisms involved in estradiol (E2)-induced SRC-3 phosphorylation and found that this occurs only when either activated estrogen receptor alpha (ERalpha) or activated ERbeta is present. Both the activation function 1 and the ligand binding domains of ERalpha are required for maximal induction. Mutations in the coactivator binding groove of the ERalpha ligand binding domain inhibit E2-stimulated SRC-3 phosphorylation, as do mutations in the nuclear receptor-interacting domain of SRC-3, suggesting that ERalpha must directly contact SRC-3 for this posttranslational modification to take place. A transcriptionally inactive ERalpha mutant which localizes to the cytoplasm supports E2-induced SRC-3 phosphorylation. Mutations of the ERalpha DNA binding domain did not block this rapid E2-dependent SRC-3 phosphorylation. Together these data demonstrate that E2-induced SRC-3 phosphorylation is dependent on a direct interaction between SRC-3 and ERalpha and can occur outside of the nucleus. Our results provide evidence for an early nongenomic action of ER on SRC-3 that supports the well-established downstream genomic roles of estrogen and coactivators.
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Affiliation(s)
- Fuzhong F Zheng
- Molecular and Cellular Biology, One Baylor Plaza, Houston, TX 77030, USA
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13
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Pasapera AM, Jiménez-Aguilera MDP, Chauchereau A, Milgrom E, Olivares A, Uribe A, Gutiérrez-Sagal R, Ulloa-Aguirre A. Effects of FSH and 17beta-estradiol on the transactivation of estrogen-regulated promoters and cell proliferation in L cells. J Steroid Biochem Mol Biol 2005; 94:289-302. [PMID: 15857748 DOI: 10.1016/j.jsbmb.2004.11.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2004] [Accepted: 11/29/2004] [Indexed: 11/26/2022]
Abstract
In the present study, we analyzed human follicle-stimulating hormone (FSH)-induced cell proliferation and transactivation of estrogen-sensitive reporter genes-in L cells stably expressing the human FSH receptor [L-(hFSHR(+)) cells]. In order to dissect the signaling pathways involved in this process, L-(hFSHR(+)) cells were transiently transfected with either the 3X-ERE-TAT-Luc or the ERE-VitA2-TK-CAT reporter genes and treated with FSH or PKA activators (cholera toxin, forskolin and 8-Br-cAMP) in the presence or absence of various kinase inhibitors. We found that FSH and all PKA activators, specifically induced transactivation of both reporter genes. Transactivation of estrogen-sensitive genes by FSH or PKA activators were blocked (approximately 90%) by H89 (PKA inhibitor) and LY294002 but not by Wortmannin (PI3-K inhibitors), 4-OH-tamoxifen, ICI182,780 or SB203580 (p38 MAPK inhibitor); PD98059 (ERK1/2 inhibitor) partially (approximately 30%) blocked the FSH-mediated effect. The combination of FSH and estradiol resulted in a synergistic effect on transactivation as well as on cell proliferation, and this enhancement was attenuated by antiestrogens. We additionally analyzed the participation of the coactivators SRC-1 and cAMP response element binding protein (CREB)-binding protein (CBP) in FSH-evoked estrogen receptor (ER)-dependent transactivation; we found that CBP but not SRC-1 potentiated FSH-induced transcriptional activation of both ER-sensitive reporters, being this effect stronger on the ERE-VitA2-TK-CAT than on the 3X-ERE-TAT-Luc reporter. Thus, in L-(hFSHR(+)) cells FSH induces transcriptional activation of estrogen-sensitive genes through an A-kinase-triggered signaling pathway, using also to a lesser extent the ERK1/2 and p38 pathways. PI3-K is not apparently involved in this FSH-mediated process since LY294002, but not Wortmannin, specifically binds ERs and completely blocks estrogen action. Presumably, CBP cooperates with the ER on genes that contain estrogen responsive elements through mechanisms involving the participation of other proteins and/or basal transcription factors (e.g. CREB), which in turn mediate the transcriptional response of estrogen-sensitive reporter genes to FSH stimulation.
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Affiliation(s)
- Ana María Pasapera
- Research Unit in Reproductive Medicine, Hospital de Gineco-Obstetricia Luis Castelazo Ayala, Instituto Mexicano del Seguro Social, Apdo. Postal 99-065, Unidad Independencia, México D.F. C.P. 10101, Mexico
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14
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Meng G, Zhao Y, Nag A, Zeng M, Dimri G, Gao Q, Wazer DE, Kumar R, Band H, Band V. Human ADA3 binds to estrogen receptor (ER) and functions as a coactivator for ER-mediated transactivation. J Biol Chem 2004; 279:54230-40. [PMID: 15496419 DOI: 10.1074/jbc.m404482200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We have recently identified the hADA3 protein, the human homologue of yeast transcriptional coactivator yADA3, as a novel HPV16 E6 target. Using ectopic expression approaches, we further demonstrated that hADA3 directly binds to the 9-cis retinoic acid receptors alpha and beta, and functions as a coactivator for retinoid receptor-mediated transcriptional activation. Here, we examined the role of endogenous hADA3 as a coactivator for estrogen receptor (ER), an important member of the nuclear hormone receptor superfamily. We show that ADA3 directly interacts with ER alpha and ER beta. Using the chromatin immunoprecipitation assay, we also show that hADA3 is a component of the activator complexes bound to the native ER response element within the promoter of the estrogen-responsive gene pS2. Furthermore, using an ER response element-luciferase reporter, we show that overexpression of ADA3 enhances the ER alpha- and ER beta-mediated sequence-specific transactivation. Reverse transcription-PCR analysis showed an ADA3-mediated increase in estrogen-induced expression of the endogenous pS2 gene. More importantly, using RNA interference against hADA3, we demonstrate that inhibition of endogenous hADA3 inhibited ER-mediated transactivation and the estrogen-induced increase in the expression of pS2, cathepsin D, and progesterone receptor, three widely known ER-responsive genes. The HPV E6 protein, by targeting hADA3 for degradation, inhibited the ER alpha-mediated transactivation and the protein expression of ER target genes. Thus, our results demonstrate that ADA3 directly binds to human estrogen receptor and enhances the transcription of ER-responsive genes, suggesting a broader role of mammalian hADA3 as a coactivator of nuclear hormone receptors and the potential role of these pathways in HPV oncogenesis.
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Affiliation(s)
- Gaoyuan Meng
- Department of Radiation Oncology, New England Medical Center, Tufts University School of Medicine, Boston, Massachusetts 02111, USA
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