Abstract
We have identified novel estrogen receptor alpha (ERα) antagonists using both cell-based and computer-based virtual screening strategies. A mammalian two-hybrid screen was used to select compounds that disrupt the interaction between the ERα ligand binding domain (LBD) and the coactivator SRC-3. A virtual screen was designed to select compounds that fit onto the LxxLL peptide-binding surface of the receptor, based on the X-ray crystal structure of the ERα LBD complexed with a LxxLL peptide. All selected compounds effectively inhibited 17-β-estradiol induced coactivator recruitment with potency ranging from nano-molar to micromolar. However, in contrast to classical ER antagonists, these novel inhibitors poorly displace estradiol in the ER-ligand competition assay. Nuclear magnetic resonance (NMR) suggested direct binding of these compounds to the receptors pre-complexed with estradiol and further demonstrated that no estradiol displacement occurred. Partial proteolytic enzyme digestion revealed that, when compared with 17-β-estradiol- and 4 hydroxy-tamoxifen (4-OHT) bound receptors, at least one of these compounds might induce a unique receptor conformation. These small molecules may represent new classes of ER antagonists, and may have the potential to provide an alternative for the current anti-estrogen therapy.
Original language | English (US) |
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Pages (from-to) | 351-360 |
Number of pages | 10 |
Journal | Journal of Steroid Biochemistry and Molecular Biology |
Volume | 88 |
Issue number | 4-5 |
DOIs | |
State | Published - Apr 2004 |
Keywords
- Antagonist
- Coactivators
- Estrogen receptor
- SRC
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism
- Biochemistry
- Molecular Medicine
- Molecular Biology
- Endocrinology
- Clinical Biochemistry
- Cell Biology