Inhibition and IL-3 rescue of FLT3/ITD-transfected BaF3 cells treated with CEP-701.

(A) Triplicate samples of 50 000 cells were incubated in 96-well plates with increasing CEP-701 concentrations. BaF3 cells were cultured with IL-3 at 1 ng/mL (solid line), whereas BaF3/ITD cells were cultured with (dotted line) or without (dashed line) IL-3. After 48 hours of incubation, cell proliferation was assessed with the MTT assay, and the results, in the form of optical densities, were plotted as percent untreated (DMSO) control. (B) IL-3 has no effect on the inhibition of FLT3 by CEP-701. BaF3/ITD cells were incubated with CEP-701 with or without IL-3, then assayed for FLT3 phosphorylation as in Figure1A.