Cell cycle arrest does not affect SMC3 and ERα expression. (A) MCF7 cells were grown under normal growth or serum-free conditions and analyzed by bromodeoxyuridine (BrdU) and propidium iodide-based flow cytometry. Serum withdrawal induces a clear decrease in the S phase fraction and increase in the G1 cell fraction. (B) Total RNA from cells as treated in (A) was harvested, reverse-transcribed and gene expression was measured by qRT-PCR. SMC3 and ESR1 expression were normalized to 28S ribosomal mRNA, graphed relative to the control sample and expressed as relative mRNA expression; mean values + SD, n = 2. (C) MCF7 cells were grown as in (A) and (B) and SMC3 and ERα protein levels were analyzed by Western blot analysis. β-Actin is shown as loading control.