Figure 7

Caspase-8 reconstitution activates the p53-mediated mitochondrial pathway induced by etoposide. A, cleavage of procaspase-9 and Bid were analyzed by Western blot with caspase-9 and Bid antibodies 24 h after drug treatment. Exo and endo represent exogenous and endogenous, respectively. B, effects of drug treatment on the mitochondrial membrane potential (ΔΨm) in HOC313/v_1 and HOC313/c8_3 cells at 32.5°C or 37°C. Cells treated with cisplatin (10 μg/ml) or etoposide (100 μg/ml) for 10 h were subjected to JC-1 assay as described in Materials and methods. To measure ΔΨm, the ratio of red to green fluorescence of JC-1 was calculated for each sample and compared with the untreated control JC-1 fluorescence ratio at each temperature. Results are the means ± SD from three independent experiments. The bars represent the SD. The asterisk indicates a significant difference (p < 0.05) between 32.5°C and 37°C in etoposide-treated HOC313/c8_3 cells (t-test).