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Updated: May 17, 2026
09:07
Detecting the Ligand-binding Domain Dimerization Activity of Estrogen Receptor Alpha Using the Mammalian Two-Hybrid Assay
Published on: December 19, 2018
DHEA metabolites activate estrogen receptors alpha and beta.
Kristy K Michael Miller1, Numan Al-Rayyan, Margarita M Ivanova
1Department of Biochemistry and Molecular Biology, Center for Genetics and Molecular Medicine, University of Louisville School of Medicine, Louisville, KY 40292, USA.
Steroids
|November 6, 2012
Summary
Dehydroepiandrosterone (DHEA) and its metabolites influence estrogen receptor activity and gene transcription. DHEA metabolites directly bind estrogen receptors, affecting cell proliferation and estrogen-regulated genes.
Area of Science:
- Endocrinology
- Molecular Biology
- Cancer Research
Background:
- Dehydroepiandrosterone (DHEA) levels are linked to postmenopausal breast cancer risk, though some studies present conflicting evidence.
- Understanding the role of DHEA and its metabolites in estrogen receptor (ER) signaling is crucial for clarifying its impact on breast cancer.
Purpose of the Study:
- To investigate how DHEA and its metabolites modulate estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ)-regulated gene transcription.
- To assess the effect of DHEA and its metabolites on cell proliferation.
Main Methods:
- Transient transfection assays in HEK-293 and HepG2 cells to examine ERα and ERβ activation by DHEA and metabolites.
- Use of ER antagonists (fulvestrant, 4-hydroxytamoxifen, R,R-THC), P450 inhibitor (miconazole), and aromatase inhibitor (exemestane) to elucidate mechanisms.
- Measurement of endogenous estrogen-regulated gene expression (pS2, progesterone receptor, cathepsin D1, NRF-1).
- In vitro binding assays to assess competition with 17β-estradiol for ERα and ERβ.
- MCF-7 cell proliferation assays.
Main Results:
- DHEA, androstenediol, and DHEA-S activated ERα; androstenedione, DHEA, androstenediol, and 7-oxo DHEA activated ERβ.
- DHEA and its metabolites increased the expression of endogenous estrogen-regulated genes in an ER-subtype, gene, and cell-specific manner.
- DHEA metabolites, unlike DHEA, directly competed with 17β-estradiol for ERα and ERβ binding.
- DHEA metabolites stimulated MCF-7 cell proliferation.
Conclusions:
- DHEA metabolites directly interact with both ERα and ERβ in vitro.
- These interactions modulate the transcription of estrogen target genes and influence cell proliferation.
- The findings clarify the complex role of DHEA and its metabolites in estrogen signaling pathways relevant to breast cancer.
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