The BRAF V600E-specific inhibitor PLX4032 (#S1267) and the MEK1 inhibitor AZD6244 (#S1008) were purchased from Selleck Chemicals (Houston, TX), dissolved in Dimethyl sulfoxide (DMSO) with a stock concentration of 10 mm and stored at −20 °C. PLX4032 and AZD6244 were used to treat cells for 24 h at 0.5 and 0.2 μm, respectively, where indicated in the manuscript. DMSO was used as the vehicle control.