Figure 5. β-catenin-LEF1 and YAP1 Co-regulate Apoptotic Sensitivity of Acquired MAPKi-resistant Melanoma Cells.
(A) Western blot (WB) analysis of indicated resistant melanoma cell lines (cultured with 1 μM MAPKi) for levels of cleaved PARP1 (cPARP1), LEF1, and GAPDH (loading control). Cells were treated with DMSO or GSK3βi (10 μM CHIR99021), −/+ LEF1 over-expression, for 1–2 days.
(B–D) As in A, except cell lysates collected at 12 and 24 h and probed for BIM levels (B, D) or harbored shVector (V) or shYAP1 (C, D).
(E) Clonogenic assays of indicated resistant cell lines (cultured with 1 μM MAPKi) treated with DMSO or GSK3βi (10 μM CHIR99021) for 14 d, −/+ YAP1 knockdown.
(F, G) As in A, except cells −/+ YAP1 over-expression and WBs were probed for YAP1 and cPARP1 (F) or BIM (G).
(H) As in E, except −/+ YAP1 over-expression; all cultures for 14 d except M238 DDR cultures with GSK3βi (22 d).