Figure 1. FL impairs effects of FLT3 inhibitors on Wt-FLT3 co-expressing cells.

A. Mutant-FLT3 32D cells were treated with increasing concentrations of the indicated FLT3 inhibitors in the presence or absence of FL at 10 or 50ng/ml for 48 hours. Fold changes to GI₅₀ values without FL are shown. B. MV4;11 cells and MOLM14 cells were treated with increasing concentrations of quizartinib or lestaurtinib with or without 50ng/ml FL for 72 hours. Fold changes to GI₅₀ values without FL are shown. C. Sole ITD-FLT3 expressing 32D cells and Wt- and ITD-FLT3 co-expressing cells were treated with increasing concentrations of quizartinib with or without FL at 50ng/ml for 24 hours and then processed to measure the binding of Annexin V and PI by flow cytometry to assess induction of apoptosis. D. 32D cells were co-cultured with COS-7 or FL-COS-7 cells overnight, followed by exposure to varying concentrations of quizartinib for 48 hours to assess apoptosis induction. E. MTT assay was performed at 24 hours after exposure to varying concentrations of quizartinib in 32D and COS-7 or FL-COS-7 co-culture condition. Error bars represent the mean values ± S.D. from at least three independent experiments (*P < 0.05, **P < 0.01, ***P < 0.001).