Figure 5.

P36-induced apoptosis in ALK-positive tumor cells is p53 dependent. Cost ALCL (a) or SH-SY5Y neuroblastoma (b) cells were incubated with p53-specific (a pool of four siRNAs for Cost or two distinct siRNAs for SH-SY5Y) or non-targeted control pool (ctl) siRNAs for 48 h before addition of P36 or culture medium (no peptide) for another 48 h. Cell viability (left) and western blot analysis of p53 expression (middle) were assayed at that time. The intensity of p53 bands relative to loading controls (GAPDH, actin) was quantified by image analysis (graphs on the right). Results display one of two representative experiments with triplicate samples. Statistical test: Student's t-test. NS, non significant; *P<0.05; **P<0.01; ***P<0.001