Fig. 4: Gilteritinib induces FLT3 upregulation, which is abrogated by CUDC-907.

A FLT3-ITD AML cell lines MOLM-13 and MV4-11 were treated with gilteritinib, CUDC-907, both, or neither for 4, 8, 12, or 24 h, at concentrations of 12.5 or 25 nM, as indicated. Western blots were generated using whole-cell lysates. One representative blot is shown. Densitometry measurements, compared to vehicle control and normalized to β-actin, are shown below the corresponding blots. B MOLM-13 and MV4-11 cells were treated as described in panel A and then stained with annexin V/PI and subjected to flow cytometry analysis. **p < 0.01 and ***p < 0.001 compared to single-drug treatments at the same timepoint. C MOLM-13, MV4-11, and primary FLT3-ITD positive AML patient sample AML#207 were treated with gilteritinib, CUDC-907, both, or vehicle control for 24 h at the indicated concentrations. Total RNA was extracted, and FLT3 transcripts relative to GAPDH were determined by real-time RT-PCR. *p < 0.05, **p < 0.01, and ***p < 0.001 compared to vehicle control. D, E MOLM-13 cells were treated with CUDC-907 and/or gilteritinib for 12 h, washed, and then treated with cycloheximide for up to 3 h. Western blots were generated utilizing whole-cell lysates. The fold changes for the FLT3 densitometry were assessed via comparison to vehicle control and normalized to β-actin. Representative blots are shown in panel (D), while densitometry measurements are graphed in panel (E). **p < 0.01, ***p < 0.001, and ns indicates not significant.