2.3. In vitro kinase assay

Cell-free kinase activity assays were performed at Reaction Biology Corporation. Briefly, kinases were incubated with substrates, 100 μM ATP and a 3-fold serial dilution of compounds starting at 1 μM. DMSO was used as control. For single-dose inhibition of FLT3-ITD and Src kinase activity, compounds were tested at 500 nM. Experiments were performed in duplicates. The concentrations of kinases and substrates used in the assays are indicated on Table S1. Kinase activity was quantified using the ADP-Glo™ Kinase Assay System (Promega, Madison, WI) following the manufacturer's recommendations.