Fig. 6

Involvement of Fas in compound-induced cell death of A549 cells. a A549 cells were treated with C1 or C2 for 72 h and harvested for western blotting of caspase-8 and caspase-9. Representative results of two different experiments are shown. b A549 cells cultured in the presence of 10 μM C1 for 48 h or C2 for 72 h were harvested, and cell surface Fas expression was analyzed. Representative histograms of three different experiments are shown. The dotted line histogram indicates cells stained with isotype control. The broken line and filled gray histograms indicate Fas expression in cells treated with vehicle and compound, respectively. Inset numbers indicate mean fluorescence intensities relative to the vehicle control. c A549 cells were preincubated with the Fas/Fas ligand antagonist kp7-6 and were cultured in the presence of 10 μM C1 for 48 h [left panel] or C2 for 72 h [right panel]. Cells were harvested and annexin V/propidium iodide staining was performed. Percentages of annexin V(+) cells are presented as the mean ± SE of 3 independent experiments; * indicates p < 0.05