Table 2

Reversal of BCRP-mediated SN-38 resistance by TAG-compoundsa

CompoundReversal index
1 μm3 μm
TamoxifenNT1.02 ± 0.02
TAG-1NT1.11 ± 0.06
TAG-2NT1.26 ± 0.02
TAG-3NT1.08 ± 0.08
TAG-5NT1.17 ± 0.11
TAG-7NT1.15 ± 0.14
TAG-8NT1.67 ± 0.02
TAG-111.36 ± 0.041.91 ± 0.02
TAG-12NT1.07 ± 0.04
TAG-13NT1.09 ± 0.01
TAG-721.12 ± 0.12NT
TAG-1261.31 ± 0.14NT
TAG-1392.32 ± 0.084.02 ± 0.12
  • a K562/BCRP cells were cultured for 5 days with increasing concentrations of SN-38 in the absence or presence of reversing agents (1 or 3 μm, as indicated). Cell numbers were counted with a Coulter counter, and concentration of drug required for IC50 was determined. Reversal index is the ratio of IC50 in the absence of reversing agent divided by that in the presence of reversing agent. Data are represented as mean values ± SD from triplicate determinations. NT, not tested.