Effect of snake venom toxin on ROS generation and the expression of death receptors in human colon cancer cells. a, Effect of snake venom toxin on ROS generation by treatment of snake venom toxin in colon cancer cells. After treatment of snake venom toxin for 30 min, the cells were incubated with 10 μM DCF-DA at 37°C for 4 h, and then washed twice with PBS. The fluorescence intensity of DCF was measured in a microplate-reader at an excitation wavelength of 485 nm and an emission wavelength of 538 nm. b, Two colon cancer cells, HCT116 cells and HT-29 cells were treated with snake venom toxin (0.1, 0.5, 1 μg/ml) at 37°C for 24 h, and equal amounts of total proteins (50 μg/lane) were subjected to 12% SDS-PAGE. Expression of DR4, DR5 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. Columns, means of three experiments, with triplicates of each experiment; bars, SD. *, p <0.05, significantly different from non treated control group.