Table 1.

Effects of PFT-α and -β on the cytotoxicity of a number of anticancer drugs in human, wild-type p53–expressing HCT116 and A2780 cancer cell lines as assessed by 96-hour sulforhodamine B assays

TreatmentA2780 IC50 values (μmol/L)
HCT116 IC50 values (μmol/L)
Alone+PFT-αRatio+PFT-βRatioAlone+PFT-αRatio+PFT-βRatio
Cisplatin0.32, 0.380.330.940.511.450.54, 0.41.02.120.541.14
0.50, 1.000.780.622.051.641.4, 1.91.951.182.11.27
Doxorubicin0.0039, 0.00330.0010.270.00691.910.012, 0.0090.0050.480.0070.67
0.008, 0.00610.00480.680.00320.450.023, 0.0300.0220.830.0180.68
Etoposide0.074, 0.0700.0320.440.0270.380.19, 0.310.190.760.210.84
0.019, 0.1280.00910.120.00910.121.9, 2.12.21.12.81.4
Paclitaxel1.0, 1.30.280.240.210.180.4, 0.90.230.350.651.0
0.51, 1.30.270.310.370.420.3, 0.40.330.940.340.97
  • NOTE: PFT-α and -β were used at 10 μmol/L, the maximum nontoxic dose. Similar results were obtained at 30 μmol/L (data not shown). Cells were pretreated with PFT-α and -β for 1 hour prior to drug treatment, and then for a subsequent 96 hours. Similar results were obtained with a 16- and 22-hour pretreatment (data not shown). Ratios >1 indicate protection, and ratios <1 indicate enhanced cytotoxicity. For other details, see Materials and Methods.