Melanoma cell lines plated in 96-well plates were transfected with siRNA pools (100 nM) targeting GNPAT, SUMO1, SPINT2, FLI1, and SSX1 for 4 h, followed by treatment with CDDO-Me at 50 nM (a) or the indicated doses (b). After 72 h, cell viability was determined by MTT assays. The percent of cell viability in each treatment group was normalized to negative control, cells treated with si-NSC. Each experiment for cell viability assay was carried out three times. Each bar denotes mean ± SD of three experiments. CM, CDDO-Me; D-FECT 3, transfection reagent.