Figure 3

GSIXII-induced cell death involved a canonic intrinsic apoptotic pathway. Cell death triggered by GSIXII depended on caspase activity. Breast cancer cells were pretreated with the pan-caspase inhibitor QVD-OPH (20 μM) before GSIXII treatment at 15 μM for 48 hours and analyzed for Apo2.7 or Annexin-V staining (more suitable for the MCF7 caspase-3 deficient cell line). Data are the means of positive cells ± SEM; n = 3. (B) Bax siRNA protected breast cancer cells from GSIXII-induced apoptosis. SiRNA (control (Ct) or Bax)-transfected cells were treated with 15 μM GSIXII before Apo2.7 immunostaining and flow-cytometry analysis. Represented data are the means of positive cells ± SEM, from three independent experiments.