Histone Deacetylase Inhibitor Trichostatin A Represses Estrogen Receptor α-Dependent Transcription and Promotes Proteasomal Degradation of Cyclin D1 in Human Breast Carcinoma Cell Lines

Abstract

Tamoxifen has been shown to inhibit ERalpha-mediated cyclin D1 transcription, and acquired resistance to tamoxifen is associated with a shift to ERalpha-independent cyclin D1 up-regulation. Taken together, our data show that TSA effectively induces cyclin D1 down-regulation through both ERalpha-dependent and ERalpha-independent mechanisms, providing an important new strategy for combating resistance to antiestrogens.