Effect of snake venom toxin on the expression of apoptosis regulatory proteins in human colon cancer cells. a, HCT116 cells and HT-29 cells were treated with different concentrations (0.1, 0.5, 1 μg/ml) of snake venom toxin at 37°C for 24 h. Equal amounts of total proteins (50 μg/lane) were subjected to 12% SDS-PAGE. Expression of cleaved caspase-3, cleaved caspase-8 and cleaved caspase-9 was detected by Western blotting using specific antibodies. b, HCT116 cells and HT-29 cells were treated with different concentrations (0.1, 0.5, 1 μg/ml) of snake venom toxin at 37°C for 24 h. Equal amounts of total proteins (50 μg/lane) were subjected to 12% SDS-PAGE. Expression of Bax, Bcl2 and β-actin was detected by Western blotting using specific antibodies. Columns, means of three experiments, with triplicates of each experiment; bars, SD. *, p <0.05, significantly different from non treated control group. c, HCT116 cells and HT-29 cells were treated with different concentrations (0.1, 0.5, 1 μg/ml) of snake venom toxin at 37°C for 24 h. And cytosol extract was prepared as described in methods. Equal amounts of total proteins (50 μg/lane) were subjected to 12% SDS-PAGE. Expression of cytochrome C and β-actin was detected by Western blotting using specific antibodies. β-actin protein was used an internal control. Each band is representative for three experiments.