Cell cycle distribution of MDA-MB-231 cells with downregulated PKCα. MDA-MB-231 cells were transfected with two different siRNAs targeting PKCα (α #1 and α #2) or a control oligonucleotide. After transfection, cells were incubated with complete medium (CM) or serum-free medium (SFM) for 24 hours. Adherent cells were thereafter subjected to Western blot (A) or propidium iodide staining and flow cytometry (B and C). Western blots are representative of three independent experiments. Data in B and C (mean ± SEM, n = 3) show the percentage of cells in s-phase.