In vitro inhibitor specificity profiles with recombinant Fes and Flt3 kinases.

In vitro kinase assays were performed with recombinant full-length Fes as well as wild-type (WT), ITD and D835Y forms of the Flt3 kinase domain (Z’-Lyte assay; see Materials and methods). Each inhibitor was tested in triplicate over a range of concentrations with the ATP concentration set to the Km value for each kinase. IC50 values were calculated by non-linear regression analysis of the resulting dose-response curves. Also included in the table are the IC50 values for growth suppression by each compound in four AML cell lines, calculated from the dose-response curves shown in Fig 2. Note that MV4-11, MOLM-13, and MOLM-14 are Flt3-ITD+, while THP-1 is wild-type for Flt3.