Figure 6.

M3814 enhances the effect of DNR/AraC combination therapy in acute leukemia cells. (A) Molm-13, Molt-4, MV4-1, THP-1 and HL-60 cells were pre-treated with the indicated concentrations of M3814 or vehicle for 45 min before the addition of 1 nM DNR and increasing concentrations of Ara-C at AraC:DNR ratios: 0.5, 1, 2, 4 and 8. Cell viability was assessed by the CellTiter-Glo assay on D 4. (B) Combination activity in the above treatment was assessed by the Bliss synergy method using Combenefit software. (C) Molm-13, Molt-4, MV4-11, THP-1, HL-60 and BM CD34 + cells isolated from two independent healthy donors were pre-treated with M3814 (300 nM) for 45 min followed by addition of increasing DNR concentrations in combination with a fixed dose of Ara-C (50 nM). Cell viability was assessed on day 3 by the CellTiter-Glo assay. IC50 values were calculated using GraphPad Prism. Representative data from three independent experiments is shown. (D) MOLM-13, MV4-11 and MOLM-14 cells were treated with CPX-351 (62.5 nM) with or without M3814 (500 nM) for indicated treatment times. Percentages of annexin V positive cells were determined by flow-cytometry and plotted as stacked bars. (E) Left: MOLM-13 cells were cultured with or without MSC and treated with CPX-351 (62.5 nM) with or without M3814 (500 nM). 25,000 MSC were seeded one day before starting co-culture. Percentages of annexin V positive cells in MOLM-13 cells were determined by flow-cytometry. Right: Inhibition of apoptosis in MOLM-13 cells co-cultured with MSC and treated with CPX-351 with or without M3814. **** p < 0.0001.