Comparative apoptotic and cytotyoxic effects of ST1926 and CD437 in myeloid leukemia cell lines. KG1 (A), HL-60 (B), U937 (C), and Kasumi (D) cells (300 000/mL) were treated with vehicle or the indicated concentrations of ST1926 and CD437 for the indicated amount of time. The apoptotic index (left panels) or the number of viable cells (right panels) was determined on aliquots of the cell cultures. Results are expressed as the mean ± SD of 3 replicate cultures. The data are representative of 2 independent experiments. *Significantly higher or lower than the corresponding vehicle-treated group (P < .01 according to the Student t test).