TITLE:
More Stable, More Estrogenic: The SERM-ERα LBD Complex
AUTHORS:
Li Gao, Yaoquan Tu, Leif A. Eriksson
KEYWORDS:
Breast Cancer; Tamoxifen Resistance; Molecular Dynamics Simulations;
Dihydrobenzoxathiin; SERM
JOURNAL NAME:
Journal of Biophysical Chemistry,
Vol.2 No.3,
August
9,
2011
ABSTRACT: Many synthetic selective estrogen receptor modulators (SERMs) have been cocrystallized with the human estrogen receptor α ligand binding domain (ERα LBD). Despite stabilizing the same canonical inactive conformation of the LBD, most SERMs display different ligand-dependent pharmacological profiles. We show here that increased partial agonism of SERMs is associated with increased conformational stability of the SERM-LBD complexes, by investigation of dihydrobenzoxathiin-based SERMs using molecular modelling techniques. Analyses of tamoxifen (TAM) and 4-hydroxytamoxifen (OHT) in complex with the LBD furthermore indicates that the conversion of TAM to OHT increases both the affinity to ERα and the partial agonism of the anti-cancer drug, which provides a plausible explanation of the counterintuitive results of TAM therapy.