Effects of CD437 on viability, DNA fragmentation, and DEVD-amc hydrolytic activity in the ATRA-resistant NB4.306 cell line. NB4 or NB4.306 cells (300,000/mL) were treated for 10 hours with vehicle (DMSO, Control) or with 10⁻⁶ mol/L CD437. At the end of the treatment cells were obtained and processed for analysis. White columns indicate the number of viable cells (erythrosin staining), black columns indicate the amount of fragmented DNA (diphenylamine assay), and shaded columns indicate DEVD-amc hydrolytic activity. Results are the mean ± SD of three separate culture dishes.