Western blot analyses of CLOCK and ERα expression in cells treated with E2 or ICI.

<p>A, ERα and ERβ expression in MCF-7, T47D, MDA-MB-231, and MCF10A cells. B, CLOCK expression in MCF-7, T47D, MDA-MB-231, and MCF10A cells that had been treated with vehicle (control) or 1 µM E2 for 24 h. Cells were cultured in 5% charcoal striped FCS and phenol red free medium for 2 days before stimulated with E2. C, CLOCK and ERα expression in MCF-7, T47D and MDA-MB-231 cells that had been treated with vehicle, 1 µM E2 or 0.1 µM ICI alone or in combination for 24 h. Cells were cultured for 2 days in 5% charcoal striped FCS and phenol red free medium for two days before they were treated with ER ligands. D, CLOCK and ERα expression in T47D cells transfected with empty vector pcDNA3 or pcDNA3-Flag-ERβ. E, CLOCK and ERα expression in MCF-7 cells transfected with control shCon or two different shERα (shERα#1 and shERα#2). F, CLOCK expression in MCF-7 cells transfected with pcDNA3 or pcDNA3-Flag-ERα. B-F, 24 h after transfection, the cells were harvested and subjected to western blot analysis. In all experiments (A-F), β-actin expression was used as a reference. The blot shown is the representative result from three independent experiments. Image of the blot is shown in the top panel of each figure, with the quantitative analysis of the bands in the blot shown in the plot below. The levels of CLOCK or ERα signal obtained from control cells were set to 1. All experiments were repeated at least three times. Data shown in the graphs are the means ± SDs of three experiments. <i>P</i> value was determined by ANOVA with Bonferroni test (*, <i>P</i><0.05. ns, not significant).