Table 2

Modulation of multidrug resistance in MRP1-PEAKSTABLE transfectants by LY402913

Cell LinesIC50a (μg/ml; fold-shiftb/relative resistancec)
VincristineEtoposideDoxorubicinDaunorubicinEpirubicin
monMRP1A0.0026 ± 0.0009d (17.9/2.2)0.167 ± 0.021 (7.6/1.0)0.151 ± 0.015 (2.9/1.0)0.010 ± 0.0032 (2.1/1.2)0.0055 ± 0.0007 (3.6/0.7)
monMRP1B0.0027 ± 0.0010d (20.4/2.3)0.188 ± 0.046 (9.1/1.2)0.175 ± 0.030 (3.4/1.2)0.011 ± 0.0018 (2.5/1.4)0.0083 ± 0.0008 (3.3/1.1)
hMRP10.0029 ± 0.0010d (23.6/2.5)0.245 ± 0.024 (8.9/1.5)0.163 ± 0.028 (7.2/1.2)0.012 ± 0.0044 (4.7/1.5)0.0091 ± 0.0020 (8.7/1.2)
Vector control0.0012 ± 0.0008 (4.0/1.0)0.161 ± 0.025 (1.6/1.0)0.147 ± 0.044 (1.4/1.0)0.008 ± 0.0003 (1.3/1.0)0.0079 ± 0.0011 (1.6/1.0)
  • a The drug concentration that inhibited growth by 50%. The values are the means ± SE of three to five experiments performed in quadruplicate.

  • b Fold-shift represents the ratio of mean IC50s in the absence of modulator (see Table 1) to the values in the presence of 5 μm LY402913.

  • c Relative resistance values are the ratios of the mean IC50s of MRP1 transfectants to the vector control cells both measured in the presence of 5 μm LY402913.

  • d Significantly different from vector control (P < 0.01).