CEP-701 inhibits FLT3 phosphorylation and induces cytotoxicity in primary AML samples.

(A) MTT dose-response assays on patient samples performed in triplicate as described previously.23 Those samples found by RT-PCR to harbor a FLT3/ITD mutation are denoted with an asterisk. RT-PCR on sample 7 revealed the presence of an Asp835 point mutation. (B) Samples for which adequate cells were available were assayed for phosphorylated FLT3 (upper panel) by incubating them for 1 hour in the absence (−) or presence (+) of 50 nM CEP-701 prior to lysis and immunoprecipitation/immunoblotting. The blot was stripped and reprobed with anti-FLT3 antibody (lower panel) to verify equal protein loading.