Figure 4

Sin3A is required for maximum growth of ERα-positive, but not ERα-negative, breast cancer cells. ERα-positive (A, B) MCF7 and (C, D) T47D cells, or ERα-negative (E, F) MDA-MB-231 and (G, H) Hs578T cells, were transfected with either scrambled (scr.) negative control or Sin3A siRNA. Cells were then treated with vehicle ethanol (EtOH) or 10 nM estrogen (E2). Cells from each group were harvested at daily intervals, and the number of live cells was determined by trypan blue exclusion and counting. Error bars show the standard error of the mean of three independent experiments. Lysates from 72 and 96 hour time points were subjected to western blot analysis to confirm efficient knockdown of Sin3A (B, D, F, H). Blots were reprobed for ERα and the loading control, β-actin. To determine significance of loss of Sin3A on estrogen-induced growth of cells in (A) and (C), student's t tests were performed comparing scrambled and Sin3A siRNA samples at each time point, *p < 0.05.