Fig. 4. (A) Cumulative levels of NO (expressed as concentration of nitrite) produced by compounds 4–9 and sodium nitroprusside (SNP). PC3 cells were treated with individual compounds at 100 μM for 12 h, 24 h, and 48 h at 37 °C, and the concentrations of nitrite in the cell supernatants were calculated according to the calibration curve generated with NaNO2 using the Griess assay. Data are expressed as the mean value (μM) ± SD from three independent experiments. (B) Effects of NO scavenger carboxy-PTIO on the antiproliferative activity of 9. PC3 cells were pretreated with the indicated concentrations of carboxy-PTIO for 1 h and then treated with 0.05 μM of compound 9 for another 48 h. The results are expressed as the percentage of cell growth inhibition relative to control cells. Data are the mean value ± SD obtained from three independent determinations.
