SKOV3 cells in serum free media were incubated with DPI (A), NAC (B), curcumin (C), or EUK-134 (D). (A)For DPI, proliferation was measured using ProMega Cell Titer 96 AQueous One solution assay as previously described. (B–D)The reducing effects of the other antioxidants were not compatible with the MTS assay. Therefore, for NAC, EUK-134, and curcumin cellular proteins were stained with 0.4% sulforhodamine B at the indicated times and assayed as described in Materials and Methods. The data are representative of the mean of three experiments. The data were analyzed using Student’s t-test and values were significantly different from untreated cells as indicated. * p<0.01, **p<5×10−6, ***p<2×10−12.