Fig 2: Western blot analysis of PS-1 and P-β-catenin in nonaggressive and aggressive melanoma cells. Western blot results with corresponding densitometric analysis of WB bands showed decreased PS-1 protein expression compared with control cells (reference) in two separate nonaggressive melanoma cell lines, WM1552C (A) and UACC1273 (B), after exposure to normal skin keratinocytes (keratoCC) and normal dermal fibroblasts (fibroCC) (* p < 0.05). (C) Western blot results with corresponding densitometric analysis of WB bands of cell lysates from aggressive melanoma cells (Sk-Mel28, A375, and C8161) showed lower PS-1 levels than results from nonaggressive melanoma cells (WM1552C). (D) Western blot results with corresponding densitometric analysis of WB bands also showed increased Wnt signaling, as demonstrated by the decreased levels of P-β-catenin (P-β-cat), in the aggressive versus nonaggressive melanoma cells analyzed.

Fig 3: Effects of GSI treatment on PS-1 and P-β-catenin levels in aggressive melanoma cells. (A) Western blot results and relative densitometric analysis of bands showed that PS-1 expression increased in the aggressive human melanoma cell lines C8161, A375, and Sk-Mel28 when treated for 72 h with 15 μM or 30 μM GSI (DAPT) compared with vehicle-treated cells (cntl). (B) Western blot results and relative densitometric analysis of bands also showed that treatment of C8161, A375, and Sk-Mel28 for 72 h with 15 μM DAPT significantly increased levels of P-β-catenin (P-β-cat) compared with vehicle-treated cells (cntl) (* p < 0.05).