Effect of Rac3 inhibition on cell proliferation and apoptosis. MDA-MB-231, MCF-7 and MCF-10A cells were treated with 10 nM siRNA (control or Rac3). (A) Cell survival was detected by a MTS assay after 24, 48, 72 and 96 h of treatment. Mean ± S.E., N=5 independent experiments. *** P<0.001 (B) After 96 h siRNA treatment, distribution of cells in the cell cycle was quantified by flow cytometry. Mean ± S.E., N=2 independent experiments. *P<0.05 (C) After 48 h siRNA treatment, apoptosis was first induced by TNFα (50 ng/ml) during an additional 24 h, then quantified by ELISA detection of histone/DNA complex in the cytoplasm. Mean ± S.E., N=3 independent experiments. ***P<0.001 relative to the control siRNA value, defined as 100%.