Wnt/β-catenin activation enhances the expression of the pro-apoptotic proteins BIM and PUMA and diminishes levels of anti-apoptotic MCL1.

<p>A) A375 melanoma cells were treated with rhTRAIL (20 ng/mL) in the presence of WNT3A or L CM. To inhibit caspase activity, cells were also treated with 100µM zVAD-FMK. Immunoblotting analysis was performed with the indicated antibodies. B) A375 cells were pre-treated with β-catenin (<i>CTNNB1</i>) versus control siRNA. 48 hours later, the cells were treated with WNT3A CM or L CM. Immunoblot analysis was then performed with the indicated antibodies. C) Graphs represent the fold-change in protein expression in (B) from digitally-quantified immunoblots +/- SEM (n=5 blots from independent experiments). Each condition was normalized to control cells treated with L CM + control siRNA. D) A375 melanoma cells were treated with WNT3A CM versus L CM in the presence or absence of rhTRAIL (20ng/mL) in the presence of zVAD-FMK (100µM). After 24 hours, RNA was collected for cDNA synthesis and analysis by quantitative real-time PCR (qRT-PCR). Data represents mean relative expression of the indicated gene based on three replicates/group. Significant differences between groups are indicated.