Figure 4

Activation of caspase-3 and release of cytochrome c upon DTE treatment. A: Caspase-3 activation after treatment with three different concentrations of DTE in U937 cells. Cells were treated with 0, 25, 50 and 100 μg/ml of DTE for 48 h and then subjected to measure caspase-3 activity by means of cleavage of the substrate DEVD-AFC. Each value was calculated as mean ± S.D. (n = 3). Bar diagram represents fold change in caspase-3 activity taking vehicle control as 1 fold. B: Release of cytochrome c in cytosolic fraction of U937 cells after treatment with DTE in dose-dependent manner. Cells were treated with DTE (0, 25, 50, 100 ug/ml) for 48 h. and were harvested and cytochrome c level in the cytosolic fraction was determined by western blot. Protein from cytosolic fraction was subjected to SDS–PAGE and western blot using cytochrome c and beta-actin antibody. Representative blot from three independent experiments was with identical results. Relative intensity of each band after normalization with the intensity of beta-actin in a blot (below) was measured.