Fig. 3.

Competition assays using prototypical probe substrate molecules. Intracellular accumulation of [³H]-prazosin (PRZ; Bcrp probe substrate), [³H]-vinblastine (VBL; P-gp probe substrate) in Bcrp1-transfected (A) and MDR1-transfected (B) cell lines with increasing concentrations of dabrafenib from 0.1 to 50 µM. Ko: Bcrp inhibitor Ko143; LY: P-gp inhibitor LY335979. Data represent the mean ± S.D.; n = 3 for all data points. *P = 0.0439 compared with untreated wild-type cells; **P = 0.003 compared with untreated MDR1 cells.