BRY potentiates LC-induced apoptosis in U937 cells.
U937 cells (2 × 105 cells/mL) were exposed to 1 μM LC (○) and LC plus 10 nM BRY (●) for the indicated intervals. (A) DNA fragmentation was assessed by the percentage of cells exhibiting TUNEL positivity. (B) Cytotoxicity was measured by the percentage of cells exhibiting low levels of DiOC6, reflecting loss of mitochondrial membrane potential. Values represent means for triplicate experiments (± SEM). (C) Western blots illustrating degradation/activation of procaspase 3 and PARP cleavage in extracts from treated cells. (D) Morphologic evidence of apoptosis (monitored at 24 hours) were used as the end-point in conjunction with median dose effect analysis to characterize drug interactions. Varying concentrations of LC (0.1-2 μM) and BRY (0.5-10 nM) at a fixed ratio (1:5) resulted in CI values less than 1. Values correspond to the results of a representative experiment.
