Figure 3. Effects of TKIs on phosphorylated KIT with mutations on exon 9 or 11/13 or 14.

(a) COS-1 cell transfected with KIT double mutants were starved and treated with indicated doses of multiple TKIs for 30 minutes respectively. The total expression and degree of phosphorylation of KIT were determined by western blot analysis. (b) Inhibitory ratios at Css (IR_Css) of multiple TKIs, as the red arrow pointed, on KIT secondary mutations on exon 13 or 14 were determined by quantification of phosphorylated KIT/total KIT and estimated from the western blot in (a). The data are expressed as the mean ± SE of three independent experiments.