CEP-701-mediated FLT3 inhibition influenced by daunorubicin. BaF3/ITD cells were incubated in culture medium containing 10% FBS for 1 hour with the indicated concentrations of CEP-701 and daunorubicin. Cells were then lysed and FLT3 autophosphorylation was analyzed by immunoblotting as described in “Materials and methods.” The upper panel shows the blot probed with antiphosphotyrosine; the lower panel shows the same blot stripped and reprobed with anti-FLT3.