Figure 4.

ER/ERE-mediated estrogenic responses in the BG-1 FR, BG-1 NIEHS, and MCF-7 cell lines. A, Activation on the 3xERE Luc reporter. Cells were transfected with 3xERE Luc and pRL-TK (control) plasmid overnight. After changing to fresh 10% sFBS DMEM-F12 medium, cells were treated with 0, 1, or 10 nM E2 for 18 hours in the absence or presence of 1 μM ICI. E2/ERE-mediated activation was detected by luciferase reporter assays as described in Material and Methods. Data shown are the average of triplicate determinations in a representative experiment. Value were calculated relative to vehicle control and presented as ±SEM. ***, P < .001, or ****, P < .0001. B, Activation on the pS2 Luc reporter. Cells were transfected with pS2 Luc and pRL-TK (control) plasmid overnight. The treatment and luciferase reporter assay were performed as described above in panel A.