Table 1

Resistance of MRP1 transfectants to chemotherapeutic drugs

Cell LinesIC50a (μg/ml; relative resistanceb)
VincristineEtoposideDoxorubicinDaunorubicinEpirubicin
monMRP1A0.046 ± 0.017c1.264 ± 0.088c,d0.442 ± 0.042d,e0.021 ± 0.008d,e0.020 ± 0.002d,e
(9.80 ± 1.95)(4.95 ± 0.79)(2.14 ± 0.48)(2.04 ± 0.63)(1.57 ± 0.25)
monMRP1B0.056 ± 0.018c1.701 ± 0.339c0.587 ± 0.115c,d0.028 ± 0.006c,d0.027 ± 0.004c,d
(11.87 ± 2.07)(6.66 ± 0.31)(2.85 ± 0.25)(2.79 ± 0.34)(2.13 ± 0.41)
hMRP10.069 ± 0.016c2.172 ± 0.229c1.176 ± 0.155c0.057 ± 0.015c0.079 ± 0.017c
(14.81 ± 3.86)(8.50 ± 0.99)(5.77 ± 1.44)(5.65 ± 0.87)(6.27 ± 1.97)
Vector control0.005 ± 0.0020.255 ± 0.0530.206 ± 0.0530.010 ± 0.0010.013 ± 0.002
  • a The drug concentration that inhibited growth by 50%. The values are the means ± SE of three to five experiments performed in quadruplicate.

  • b Relative resistance values are the ratios ± SE of the mean IC50s of MRP1 transfectants to the vector control cells.

  • c Significantly different from vector control (P < 0.001).

  • d Significantly different from hMRP1 (P < 0.05).

  • e Significantly different from vector control (P < 0.05).