Effects of 1,000 μM aspirin and 100 μM rofecoxib on apoptosis. Representative images from light microscopy and immunofluorescence (demonstrating propidium iodide and annexin-V staining) of HCA 7, HT29 and LoVo cells with no agent (control containing DMSO and TRIS), rofecoxib and aspirin (A). The apoptosis of cells is shown as percentage at 24, 48 and 72 hours by 1000 μM aspirin, 100 μM rofecoxib. Results are expressed as mean percentage of apoptosis +/− SD (*P <0.05) (B). Caspase-3/7 activation relative to control at 12 and 48 hours. Mean and standard deviations of triplicate cultures shown (C).