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. Author manuscript; available in PMC: 2021 Oct 1.
Published in final edited form as: Mol Cancer Ther. 2021 Feb 10;20(4):676–690. doi: 10.1158/1535-7163.MCT-20-0663

Figure 1. Concurrent PP2A-activating drug treatment increases cytotoxicity of FLT3 inhibitors in MV4-11 cells and AML patient blasts with FLT3-ITD and in an MV4-11 orthotopic mouse model.

Figure 1.

A. Combination treatment decreases MV4-11 growth. MV4-11 human FLT3-ITD AML cells were cultured in triplicate with 1 nM quizartinib or 15 nM gilteritinib and/or 2 μM FTY720 or 10 μM DT-061, or DMSO control, and viable cells were counted after 24, 48 and 72 hours. B. Combination treatment increases MV4-11 apoptosis. MV4-11 cells were cultured in triplicate with 1 nM quizartinib or 15 nM gilteritinib and/or FTY720 or DT-061 at the concentrations shown, or DMSO control, and apoptosis was measured after 48 hours by annexin V/PI staining. Statistical analysis was performed by two-way ANOVA with post hoc Bonferroni testing (*p<0.05, **p<0.005, ***p<0.001). C. Combination treatment is synergistic in MV4-11 cells. MV4-11 cells cultured in triplicate on 96-well plates were treated with gilteritinib and FTY720 alone and in combination at the concentrations shown. Combination indexes were determined by Chou-Talalay analysis. D. DT-061 enhances efficacy of gilteritinib in vivo. NSG mice inoculated with MV411-luc cells on Day 0 were treated with liposomal gilteritinib and/or DT-061, or vehicle control, beginning on Day 7 (D7). Left panel shows change in photon intensity, measured by bioluminescence imaging, over time, with ***p=0.0004, comparing DT-061 and gilteritinib combination vs. gilteritinib alone on Day 49 by 2-way ANOVA with Sidak’s multiple comparison test. Right panel shows two representative mice from each treatment group on Days 7, 28, 35 and 49. E. Combination treatment increases FLT3-ITD AML blast apoptosis. FLT3-ITD AML patient blasts were plated in triplicate in RPMI 1640 medium with 1 nM quizartinib or 15 nM gilteritinib and/or FTY720 or DT-061 at the concentrations shown, or DMSO control, and apoptosis was measured after 48 hours by annexin V/PI staining. Statistical analysis was performed by two-way ANOVA with post hoc Bonferroni testing (*p<0.05, **p<0.005, ***p<0.001).