Figure 4.

Effects of calcitriol and the Braf^V600E inhibitor PLX4720 on BVE^Cyp24a1-wt-1, BVE^Cyp24a1-null-1 cells, and BVE^Cyp24a1-null-1Cyp24a1 tumor cells. Colony formation assay was used to determine the long-term effects of PLX4720 and calcitriol on cell proliferation. Cells were plated into 12-well plates (5×10² cells/well) and cultured in the presence of different concentrations of PLX4720, calcitriol, or both for 14 days. The cells were then stained with 0.5% crystal violet dye (in methanol:deionized water, 1:5) for 10 minutes. After three washes with deionized water, the crystal violet dye was released from the cells by incubation with 1% sodium dodecyl sulfate (SDS) for 2 hours before optical density 570 nm measurement. Cell viability is expressed as a percentage of the vehicle control. *, P < 0.05, statistically significant.