Figure 2
EGFR over expression does not influence estrogen-dependent proliferation . To investigate the proliferation induced by either estrogen or EGF both, parental MCF7 and MCF7-EGFR cells, were cultured in phenol red free medium with 5% charcoal treated serum for 48 hours, followed by an exposure to 0.1 nM E2, 100 ng/mL EGF or a combined exposure. The control cells were exposed to DMSO only. Cells were left to proliferate for 5 days and then fixed with 50% trichloroacid (TCA). Fixed cells were stained with sulforhodamin B, which absorption was measured at 540 nm (A). Graphs represents the average relative proliferation ± SEM of three independent experiments, * indicates significant difference of p < 0.05. To determine the role for the fast non-genomic effects of ERα, starved MCF7 parental and MCF7-EGFR cells were exposed to 10 nM E2 for the indicated times before lysates were collected and analyzed by western blot for the phosphorylation status of MAPK1/3 (B). – and + indicate negative control (DMSO) and positive control (EGF, 100 ng/mL).