Table 1.

Reversal of drug resistance in PC-6 and MCF-7 cell panels by gefitinib

DrugsCellsIC50 nmol/L (RR) *IC50 nmol/L (RR) * + gefitinib
TopotecanPC-67.27 ± 0.937.62 ± 0.27
PC-6/SN2-5H369 ± 37.2 (50.8)11.0 ± 0.92 (1.44)
MCF-7120 ± 9.1181.2 ± 12.6
MCF-7/MX4,143 ± 161 (34.5)716 ± 118 (8.82)
MCF-7/clone 85,806 ± 907 (48.4)309 ± 5.88 (3.81)
SN-38PC-64.97 ± 0.444.10 ± 0.23
PC-6/SN2-5H153 ± 2.20 (30.8)5.03 ± 0.26 (1.23)
MCF-789.4 ± 15.470.3 ± 3.35
MCF-7/MX1,139 ± 79.3 (12.7)116 ± 18.2 (1.65)
MCF-7/clone 8845 ± 63.9 (9.45)59.7 ± 1.05 (0.85)
MitoxantronePC-627.0 ± 1.8220.2 ± 1.92
PC-6/SN2-5H903 ± 5.94 (33.4)24.2 ± 0.57 (1.20)
MCF-710.5 ± 1.9810.1 ± 0.25
MCF-7/MX1,210 ± 289 (115)178 ± 16.3 (17.6)
MCF-7/clone 89,870 ± 346 (940)150 ± 31.4 (14.9)
DoxorubicinPC-623.0 ± 1.9219.2 ± 0.66
PC-6/SN2-5H30.3 ± 0.88 (1.32)25.8 ± 2.25 (1.34)
MCF-786.6 ± 11.179.0 ± 1.65
MCF-7/MX273 ± 9.29 (3.15)74.0 ± 12.6 (0.94)
MCF-7/clone 82,638 ± 17.1 (30.5)103 ± 9.92 (1.30)
VincristinePC-61.01 ± 0.021.12 ± 0.03
PC-6/SN2-5H1.20 ± 0.05 (1.19)1.08 ± 0.08 (0.96)
MCF-71.12 ± 0.101.08 ± 0.13
MCF-7/MX1.99 ± 0.12 (1.78)1.82 ± 0.12 (1.69)
MCF-7/clone 84.24 ± 0.66 (3.79)4.24 ± 0.40 (3.93)
EtoposidePC-6423 ± 21.2495 ± 8.95
PC-6/SN2-5H435 ± 7.36 (1.03)485 ± 36.9 (0.98)
MCF-71,254 ± 2491,201 ± 318
MCF-7/MX4,152 ± 442 (3.31)4,153 ± 82.9 (3.46)
MCF-7/clone 810,425 ± 905 (8.31)10,161 ± 609 (8.46)
  • NOTE: Data represent mean ± SD.

  • * RR, resistance ratio = [(IC50 in resistant cells) / (IC50 in respective parental cells)].

  • Gefitinib (10 and 2 μmol/L) were added in PC-6 and MCF-7 cell panels, respectively.