Expression analyses of proenzyme caspase-8 in response to HHQ treatment in human breast cancer cells (MDA-MB-231 and MCF-7). The breast cancer cells were treated with 12.5 μM and 25 μM of HHQ for 48 h at 37 °C. Representative western blot hybridization signals for proenzyme caspase-8 for MDA-MB-231 [A] and MCF-7 [B] and the quantitation of the signals are shown in [C] and [D], respectively. Significant decrease in expression of proenzyme caspase-8 was observed in HHQ treated cells. Data are presented as mean ± SEM of three independent experiments. *p< 0.005 represents statistically difference between control and HHQ test groups.