Fig. 6.

Effect of MRP1 and GSTP1–1 expression on SFN-mediated changes in cytoplasmic and nuclear Nrf2 levels. Parental (MCF7/WT, WT) and transgenic cells (MCF7/WTπ, WTπ; MCF7/MRP1, MRP and MCF7/MRP1π, MRPπ) were treated for 3 h with 25 μM SFN or vehicle (control) and then processed at the indicated times post-SFN treatment for determinations of cytoplasmic (A) or nuclear (B) Nrf2 levels as described in Materials and Methods. Experiments shown in A and B are derived from samples obtained in a single representative experiment. On the left are shown western blots for Nrf2 expression (uppermost panels of A and B), actin expression (lower panels of A), topoisomerase 1 (lower panels of B) and, on the right, densitometry data of relative Nrf2 expression (expressed as a percentage of the highest Nrf2 level achieved in the experiment).