title: Differential selectivity of efflux transporter inhibitors in Caco-2 and MDCK-MDR1 monolayers: a strategy to assess the interaction of a new chemical entity with P-gp, BCRP, and MRP2.
abstract: Determining the interaction of a molecule with membrane transporters is challenging because of overlapping substrate and inhibitor specificities and coexpression of multiple transporters. Caco-2 and MDCK-MDR1 cells were used to evaluate the selectivity of zosuquidar (LY335979), fumitremorgin C (FTC), and MK571 as inhibitors of P-glycoprotein (P-gp), breast cancer resistance protein (BCRP), and multidrug resistance-associated protein 2 (MRP2), respectively. Although these compounds are commonly used as transporter inhibitors, the concentrations at which they selectively inhibit P-gp, BCRP, and MRP2 have not been definitively assessed. In Caco-2 cells, which express P-gp, BCRP, and MRP2, FTC (1 µM) selectively inhibited the efflux of BCRP substrates estrone-3-sulfate and genistein; however, at 10 µM, FTC partially inhibited the efflux of P-gp substrates paclitaxel and digoxin. MK571 (50 µM), commonly used to inhibit MRP2, inhibited the efflux of P-gp and BCRP probe substrates in Caco-2 cells. In MDCK-MDR1 cells, which express human P-gp but not BCRP or MRP2, MK571 (50 µM) and FTC (10 µM) did not inhibit paclitaxel and digoxin efflux. Using Caco-2 cell monolayers, selected probe substrates, and optimized concentrations of LY335979 (3 µM) and FTC (1 µM), we propose a strategy to evaluate the interaction of a molecule with P-gp, BCRP, and MRP2.
authors.affiliation: Drug Metabolism and Pharmacokinetics, Boehringer Ingelheim Pharmaceuticals, Inc., Ridgefield, Connecticut, USA.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Mease
authors.forename: Rucha
authors.initials: R
authors.lastname: Sane
authors.forename: Lalitha
authors.initials: L
authors.lastname: Podila
authors.forename: Mitchell E
authors.initials: ME
authors.lastname: Taub
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000378:metabolism*; D000818:Animals; D018938:Caco-2 Cells; D004285:Dogs; D006801:Humans; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000378:metabolism*; D014747:Vinblastine / Q000378:metabolism
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D009363:Neoplasm Proteins; D014747:Vinblastine; C000715087:ABCC2 protein, human; C116614:ABCG2 protein, human