Estrogen Receptor Corepressors –Mechanism of Action and Role in Breast Tumorigenesis

Estrogen receptor α (ERα) is a critical player in normal breast development and breast cancer progression and disease. Its activity is not only regulated by ligands, but also through interaction with cofactor proteins termed coactivators and corepressors. There is increasing evidence that coactivators can function as oncogenes in breast cancer, however little is known about the role of corepressors. ERα corepressors are proteins which bind to ERα, and repress its transcriptional activity. We have cloned a novel ERα corepressor, SAFB1, which inhibits estrogen-mediated activation, and attenuates antiestrogen-media…