Effects of the antiretroviral drug 2'-deoxy-2'-β-fluoro-4'-azidocytidine (FNC) on P-gp, MRP2 and BCRP expressions and functions.

The purpose of the present study was to dig into recent studies designed to characterize the impacts of 2'-deoxy-2'beta-fluoro-4'-azidocytidine (FNC) on P-glycoprotein (P-gp), multidrug resistance-associated protein 2 (MRP2) and breast cancer resistance protein (BCRP). Specifically, the modulation effects of FNC on P-gp, MRP2 and BCRP protein expressions were assessed by western blot methods. 5 (and 6)-Carboxy-2',7'-dichloroflourescein (CDF) and BODIPY-prazosin were used to provide indications of alterations of MRP2 and BCRP activities. The effects of P-gp, MRP2 and BCRP on FNC were evaluated in the in situ single-pass intestinal perfusion model. The results showed that FNC at higher concentrations and with longer incubation times can upregulate the protein expression of P-gp, MRP2 and BCRP in Caco-2 cells. The upregulated proteins were also functionally active, as revealed by a lower degree of CDF and BODIPY-prazosin uptake by the cell monolayers. The intestinal absorptive coefficient (Peff) was observed to significantly increase with the inhibitors of P-gp, MRP2 and BCRP. These results suggested that FNC could modulate the expressions and functions of P-gp, MRP2 and BCRP, while P-gp, MRP2 and BCRP were involved in the efflux transport of FNC. The inductive effects of FNC on P-gp, MRP2 and BCRP suggested the possibility of FNC to contribute to the inter- and intra-individual variability of itself, as well as to alter the absorption of other drugs that may be administered concomitantly.