Quantitative Proteomics and Transcriptomics Addressing the Estrogen Receptor Subtype-mediated Effects in T47D Breast Cancer Cells Exposed to the Phytoestrogen Genistein

The present study addresses, by transcriptomics and quantitative stable isotope labeling by amino acids in cell culture (SILAC)-based proteomics, the estrogen receptor alpha(ER alpha) and beta (ER beta)-mediated effects on gene and protein expression in T47D breast cancer cells exposed to the phytoestrogen genistein. Using the T47D human breast cancer cell line with tetracycline-dependent ER beta expression (T47D-ER beta), the effect of a varying intracellular ER alpha/ER beta ratio on genistein-induced gene and protein expression was characterized. Results obtained reveal that in ER alpha-expressing T47D-ER beta cells with inhibited ER beta expression genistein induces transcriptomics and proteomics signatures pointing at rapid cell growth and migration by dynamic activation of cytoskeleton remodeling. The data reveal an interplay between integrins, focal adhesion kinase, CDC42, and actin cytoskeleton signaling cascades, occurring upon genistein treatment, in the T47D-ER beta breast cancer cells with low levels of ER alpha and no expression of ER beta. In addition, data from our study indicate that ER beta-mediated gene and protein expression counteracts ER beta-mediated effects because in T47D-ER beta cells expressing ER beta and exposed to genistein transcriptomics and proteomics signatures pointing at a clear down-regulation of cell growth and induction of cell cycle arrest and apoptosis were demonstrated. These results suggest that ER beta decreases cell motility and metastatic potential as well as cell survival of the breast cancer cell line. It is concluded that the effects of genistein on proteomics and transcriptomics end points in the T47D-ER beta cell model are comparable with those reported previously for estradiol with the ultimate estrogenic effect being dependent on the relative affinity for both receptors and on the receptor phenotype (ER alpha/ER beta ratio) in the cells or tissue of interest. Molecular & Cellular Proteomics 10: 10.1074/mcp.M110.002170, 1-17, 2011.