SU5416 and SU6668 inhibit c-kit tyrosine phosphorylation in AML blast cells.

AML blast cells (panel A: patient No. 1; panel B: patient No. 8) were quiesced by serum starvation and treated with the indicated concentrations of SU5416 for 1 hour or SU6668 for 24 hours prior to stimulation with 250 ng/mL SCF for 15 minutes. Cells were harvested, lysed, and immunoprecipitated with an anti–c-kit antibody. After SDS-PAGE and transfer to nitrocellulose, the blots were probed with an antiphosphotyrosine antibody (top) and subsequently stripped and reprobed with an anti–c-kit antibody (bottom).