Figure 8.

K18 modulates E2-stimulated expression of ERα target genes and the recruitment of ERα to its target DNA in MCF-7 cells. A, MCF-7 cells were grown in phenol-red free media stripped of steroids for at least 3 days, then cotransfected with the indicated vectors and cultured for the indicated times. Before total RNA was extracted, the cells were treated with E2 (100 nM) or vehicle (DMSO) for 1 h. Expression of the indicated transcript abundance was analyzed by quantitative RT-PCR (qPCR). HPRT was used as the internal control. All experiments were repeated at least 3 times; results are expressed as means ± SEM. B, MCF-7 cells were grown in phenol-red free media stripped of steroids for at least 3 days, then cotransfected with the indicated siRNAs. After 47 h, cells were treated with E2 (100 nM) or vehicle (DMSO) for 1 h and were subjected to qPCR analysis. Transcript abundance was analyzed by qPCR. HPRT was used as the internal control. All experiments were repeated at least 3 times; results are expressed as means ± SEM. C, MCF-7 cells, grown in phenol-red free media stripped of steroids, were transiently transfected with K18 expression vector or empty vector. 40 h post-transfection, cells were treated with E2 (100 nM) for 1 h and were subjected to ChIP analyses with the indicated antibodies.