Exposure to atovaquone induces time- and dose-dependent apoptosis of leukemia cell lines at clinically achievable concentrations. AML cell lines (THP-1 [A], MOLM13 [B], MV4-11 [C], NB4 [D], HL60 [E], and Kasumi-1 [F]), precursor B-cell lines (NALM6 [G] and RS4;11 [H]), and a chronic myeloid leukemia cell line (K562 [I]) were incubated with vehicle or the indicated dose of atovaquone for the times shown. Apoptosis was quantified by annexin V staining and flow cytometry. Means and standard errors of the mean are depicted (n = 3 for each cell line). FITC, fluorescein isothiocyanate; PBS, phosphate-buffered saline.