Figure 4.

Co-administration of INK128 and ABT-737 effectively kills AML blasts carrying FLT3 mutations or cultured in the presence of a protective microenvironment. A) Ba/F3 cells carrying FLT3-ITD or FLT3-ITD F691L were exposed to the designated concentrations of ABT-737 alone or in combination with 200 nM INK128 for 24 hrs after which cell growth and viability were assessed using the CellTiter-Glo Luminescent Assay. Alternatively, protein lysates were prepared and subjected to Western blot analysis (B). C) U937 cells expressing copGFP were co-cultured with bone marrow-derived stromal HS5 cells for 24 hrs, and exposed to 200 nM INK128 ± 500 nM ABT-737 for an additional 24 hrs. Cell death was then assessed in cop-GFP U937 cells using the Annexin V-APC/7-AAD staining assay. D) MV4-11 cells expressing luciferase were co-cultured with HS5 cells for 24 hrs and treated with INK128 (100 nM) ± ABT-737 (10 nM). After 24 hrs, a luciferase assay was performed using D-luciferin to reflect cell growth and viability. Error Bars: SD of 3 independent experiments; *P<0.0001 in each case.