Table 1

Patterns of cross-resistance in parental and cisplatin-resistant human KB epidermoid carcinoma cell lines

Chemicals Clone designationKBKB-CP.3a (LD50, μg/ml)KB-CP.5b (LD50, μg/ml)KB-CP1c (LD50, μg/ml)
S5L1M1M3M1M2L6L4L2S2M2L6
Cisplatin0.0640.250.160.270.52.83.22.91.91.56.45.77.1
 Relative resistanced42.64.48445045302310089110
Carboplatin0.773.55101524162013403238
 Relative resistance1057142134222918574554
Methotrexate0.00320.010.0050.0040.010.0180.0240.0070.0040.010.0250.0220.034
 Relative resistance3.11.51.253.15.67.42.11.33.17.86.810.6
Sodium arsenite0.310.390.320.320.641.31.60.470.580.72.82.53.3
 Relative resistance1.3112.145.21.51.92.398.110.6
5-Fluorouracil0.360.400.340.380.410.450.60.410.460.60.840.740.82
 Relative resistance1.1111.11.31.71.11.31.72.322.3
Pseudomonas exotoxin0.0150.0170.0140.0160.0160.0170.0180.0200.0140.0180.0260.0220.028
 Relative resistance1.11111.11.21.411.21.71.51.9
  • a Maintained in medium containing 0.3 μg/ml−1 cisplatin.

  • b Maintained in medium containing 0.5 μg/ml−1 cisplatin.

  • c Maintained in medium containing 1 μg/ml−1 cisplatin.

  • d Relative resistance was determined by dividing the LD50 value (μg/ml−1) of the drug for cisplatin-resistant KB cells by that for the parental KB-3-1 cell line.