(A,B) diMF-induced polyploidization (A) and expression of CD41 and CD42 (B) in 6133/MPL cells 48 hr after treatment. Data are representative of two independent experiments. (C) Transplantation of 6133/MPL cells causes AMKL in sub-lethally irradiated recipient mice. H&E-stained spleen sections revealed massive infiltration of tumor cells in transplanted mice, but not control mice. Scale bar: 50 µm. (D) Survival curve of mice transplanted with 6133/MPL cells pretreated with vehicle or 10 µM diMF for 24 hr. N=7 mice per group; p=0.0002. (E) Measurement of drug concentration in plasma after a single dose of diMF. C57Bl/6 mice were dosed orally with 66 mg/kg of diMF, and plasma concentrations of the drug were assessed at multiple time points post-treatment; n=3 animals per time point. The insert depicts decay over 2 hr. (F) Survival curve of mice transplanted with 1 million 6133/MPL cells and treated with vehicle or diMF at 33 or 66 mg/kg for 10 days, beginning two days after transplantation; n=7 mice per group. Results are representative of two independent experiments. (G) diMF induction of polyploidization of 6133/MPL cells in vivo. Forty-eight hr after transplantation, mice were fed vehicle or 66 mg/kg diMF by oral gavage twice a day for 3 days and the DNA content of the transplanted cells in bone marrow was evaluated by flow cytometry; n=3 animals per group. (H) diMF induced polyploidization of human non-DS-AMKL blasts. Human CD41+ non-DS-AMKL blasts from primary NSG recipients were treated with vehicle or 5 µM diMF for 6 days. (I, J, K) diMF reduced tumor burden and induced polyploidization of NSG mice transplanted with human non-DS-AMKL blasts from primary NSG recipients. Secondary NSG recipients were treated with vehicle or diMF at 30 or 60 mg/kg for 10 days. diMF reduced human CD41+ cells in spleen (I), peripheral blood (J), and induced polyploidization (K) of human CD41+ cells in the spleen. (L) diMF inhibition of DS-AMKL blast colony formation. Bone marrow specimens from pediatric patients with DS-AMKL were cultured in Megacult-C media with THPO and either DMSO or 5 µM diMF for 10–12 days. Representative images of anti-CD41 antibody stained colonies are shown; scale bar: 100 µm. Bar graph depicts the mean ± SD of relative colony numbers following treatment; * p<0.05.