Figure 6
From: Doxorubicin and etoposide sensitize small cell lung carcinoma cells expressing caspase-8 to TRAIL
The role of cFLIP in response of U1690 cells to combined treatment of TRAIL and doxorubicin. (A) Cleavage of PARP and caspase-3 in U1690 cells non-transfected, mock-transfected (Lipofectamine 2000 only) or transfected (24 h) with FLIPL/S or control siRNA, and then treated (24 h) with TRAIL (100 ng/ml). Percentage of cells with apoptotic nuclear morphology after transfection (24 h) with FLIPL/S or control siRNAs and subsequent treatment (24 h) with TRAIL (100 ng/ml). Results are means ± S.E.M. of three independent experiments. Statistical significance: P < 0.05, (*) versus control, (+) versus TRAIL, (x) versus doxorubicin. (B) Cleavage of PARP in U1690 cells transfected (24 h) with cFLIPL, cFLIPS or control siRNA, and then treated (24 h) with TRAIL (100 ng/ml). In (A, B) silencing of cFLIPL or cFLIPS was verified using anti-cFLIP antibody, and G3PDH was used as a loading control. (C) Cleavage of PARP, caspase-8, and cFLIPL or cFLIPS level in U1690 cells pre-treated (1 h) with CHX (5 μg/ml), and then treated (12 h) with TRAIL (100 ng/ml). An equal loading was verified using anti-G3PDH antibody. (D) Cleavage of PARP in U1690 cells transfected (24 h) with cFLIPL, cFLIPS or empty vectors, and then treated (24 or 8 h, respectively) with TRAIL (100 ng/ml). Overexpression of FLIPL or cFLIPS was controlled using anti-cFLIP antibody, and G3PDH was used as a loading control. Results are representative of three independent experiments.