Effects of DEPe on P-glycoprotein, BCRP, MRP2 and BSEP transport activity.

<p>(A) P-glycoprotein, BCRP and MRP2 activities were determined through measurement of rhodamine 123 accumulation, Hoechst 33342 retention and CF accumulation in transporter-expressing cell lines in the absence or presence of 25 μg/mL DEPe as reported in the Material and Methods. Reference inhibition of transporter activity was obtained in parallel through addition of 50 μM verapamil (P-glycoprotein inhibition), 10 μM fumitremorgin C (FTC) (BCRP inhibition) or 10 mM probenecid (OATP inhibition). Data are expressed as % of dye accumulation (P-glycoprotein and MRP2 activities) or dye retention (BCRP activity) in control untreated cells; they are the means ± SEM of at least three independent experiments. *, p<0.05 when compared to control cells (ANOVA followed by a Dunnett’s post-hoc test). (B) CF accumulation was measured in HuH-7 cells in the absence or presence of various concentrations of DEPe (from 0.1 to 50 μg/mL) or of the reference OATP inhibitor probenecid. Data are expressed as % of MRP2 activity calculated as described in Materials and Methods and are the means ± SEM of four independent assays. DEPe IC₅₀ value is indicated at the top of the graph. (C) BEI for taurocholate, reflecting BSEP activity, was determined in primary human hepatocytes in the absence or presence of 25 μg/mL DEPe, as reported in Materials and Methods. Data are the means ± SEM of three independent experiments. NS, not significant (Student’s t-test).