PDBu-induced MK differentiation of leukemic cells. (A) MK differentiation of TF-1, HeL, and K562 cells treated with increasing doses of PDBu for 3 days (left panel, CD41 surface expression; right panel, CD61 surface expression). The maximal cell differentiation was obtained with 5 nM PDBu for TF-1 and 20 nM PDBu for HeL and K562, while higher doses were toxic for the cells. Data from 5 independent experiments are expressed as means plus or minus SD. (B) Immunophenotype of TF-1 cells cultured with 5 nM PDBu for 3 days. DMSO-treated TF-1 cells (empty histograms) as controls. (C) PDBu-related cell death. Cells were treated for 3 days with the optimal doses of PDBu (5 nM for TF-1; 20 nM for HeL and K562). Cell viability is represented as percentage of the control (DMSO). Data from 5 independent experiments are expressed as means plus or minus SD. *P < .05. (D) MK differentiation of primary AML cells treated with increasing doses of PDBu for 3 days. The maximal cell differentiation was obtained with 20 nM PDBu. Data from 3 patients with AML. (E) PDBu-related cell death. Cells were treated with 20 nM PDBu for 3 days. Cell viability is represented as percentage of the control (DMSO). Data are from 11 patients.