Figure 5.

Effects of HCT on caspases-8 and caspase-3 activities in human lung cancer A549 cells. The A549 cells were treated with HCT (0, 125, 250 and 500 μg/ml) for 24 h, and then total cell extracts were incubated with (A) caspases-8 specific substrate (Ac-IETD-pNA) and (B) caspase-3 specific substrate (Ac-DEVE-pNA) respectively. The release of pNA was measured at 405 nm by a spectrophotometer as described in Materials and Methods. The experiments were done in triplicate (n = 3). *p < 0.05, **p < 0.01, ***p < 0.001 was considered significantly different in comparison with the control.