Caspase-8 mediates cisplatin-induced apoptosis in H460 sh-BAXBAK cells but not sh-NTNT control cells. (a) (i) Western blot showing siRNA-mediated silencing of caspase-8 in H460 sh-BAXBAK clones. (ii) Flow cytometry of PI-stained H460 sh-BAXBAK clones, transfected for 48 h with caspase-8 siRNA (siC8) or scrambled control (SC) and treated with cisplatin (5 μM) or TRAIL (10 ng/ml) for 48 h. Apoptotic cells are indicated by increase in sub-G0/G1 population. Data are expressed as mean±S.D. (b) (i) Western blot for caspase-8 and caspase-9 in H460 sh-NTNT cells after transfection for 48 h with C8 siRNA and treatment with cisplatin or TRAIL. Caspase-8 silencing attenuates TRAIL induced but not cisplatin-induced caspase-9 cleavage. (ii) Flow cytometry of PI-stained H460 sh-NTNT cells, transfected for 48 h with caspase-8 siRNA (siC8) or scrambled control (SC) and treated with cisplatin (15 μM) or TRAIL (10 ng/ml) for 48 h. Data are expressed as mean±S.D. (c) Western blots for PARP, caspase-8, DR4, DR5, FADD. Caspase-8 and PARP cleavage, induced by cisplatin, is attenuated after siRNA-mediated silencing of DR4, DR5 and FADD in H460 sh-BAXBAK 1C