Cytotoxic effect of APO866 in hematologic malignant cells. (A) ML-2, Namalwa, and Jurkat cells were cultured (in RPMI+10% FCS+1% P/S) after various splittings without or with 10 nM APO866. Cell death was assessed after 96 hours by flow cytometry using annexin V and 7AAD double staining. The percentage of early apoptotic cells (annexin V⁺ 7AAD⁻) are shown as ▬ and that of late apoptotic cells (annexin V⁺ 7AAD⁺) are shown as ▭. Data are presented as means of triplicate + SD. (B) Primary cells from patients with various hematologic malignancies (Nahimana et al,¹  Table 2, patients 1-32): Acute myeloid leukemia (AML; n = 10); acute lymphoblastic leukemia (ALL; n = 3); chronic lymphocytic leukemia (CLL; n = 12); T-large granular lymphocyte leukemia (T-LGL; n = 1); T-lymphoma (TL; n = 1); marginal zone lymphoma (ML; n = 3); mantle cell lymphoma (MCL; n = 1); and follicular lymphoma (FL; n = 1) were cultured and cell death monitored as in panel A. Specific cell death (%) induced by drug was calculated according to the formula scd = [(S-C) / (100-C)] × 100; where S = treated sample cell death and C = untreated sample cell death. (C) 0.5-1 × 10⁶ Jurkat cells were cultured in various media as indicated on x-axis in the presence or absence of 10 nM APO866. Specific cell death calculated as mentioned above. #P indicates number of cell splittings.