siRNA to ASMase blocks α-TEA-induced apoptosis. MDA-MB-231 cells were transfected with siRNAs to ASMase or control for 24 hrs followed by treating the cells with 40 μM α-TEA for 4 hrs. A, Ceramide levels in cellular membrane were detected by FACS analyses after immunofluorescent staining of living cells with primary ceramide antibody and fluorescence labeled secondary antibody. B, Annexin V/FACS analyses showed that siRNA to ASMase blocked α-TEA induced apoptosis. C, Western blot analyses was used to verified silencing efficiency of siRNA to ASMase using GAPDH as loading control. Data in A & C are representative of two independent experiments. Data in B are presented as means ± S.D. of three independent experiments. (* = significantly different, P < 0.05).