Figure 6.

Caspase-8 activation is blocked in cisplatin-resistant cells but can be activated by TRAIL. (a) (i) Western blot for PARP and caspase-8 in H460 and MOR paired parental (Par) and cisplatin-resistant (CISPR) cells after 24 h cisplatin (15 μM) or TRAIL (10 ng/ml) treatment. (ii) Flow cytometry of PI-stained H460 and MOR paired parental (Par) and cisplatin-resistant (CISPR) cells after 24 h cisplatin (15 μM) or TRAIL(10 ng/ml) treatment. Data are expressed as mean±S.D. (b) Representative images of cells stained for ceramide (green) in H460 Par and CISPR cells. Cells were treated for 24 h with cisplatin (15 μM) or 4 h with TRAIL (10 ng/ml). (c) Fluorescent ASM activity assay shows PAR and CISPR cells for H460 and MOR have equivalent baseline levels of ASM activity with a small increase after 24 h cisplatin treatment