title: Inhibition of P-glycoprotein by cyclosporin A analogues and metabolites.
abstract: The interaction between P-glycoprotein (P-gp) from membranes isolated from multidrug-resistant Chinese hamster ovary cells and cyclosporin A (CsA) analogues and its metabolites was characterized. Screening of these latter as chemosensitizers was performed using three different assays: (i) vinblastine uptake, (ii) photoaffinity labeling by [125I]iodoaryl azidoprazosin, and (iii) P-gp ATPase activity. Oxidation of the hydroxyl group at position I of CsA (200-096), CsG (215-834), or CsD (PSC-833) increased their inhibition of P-gp. CsA analogues (208-032, 208-183) modified at position 11 retained their ability to inhibit P-gp while analogues modified at position 2 (CsC and CsD) lost their efficiency. The inhibitions induced by metabolites of CsA were also compared to those obtained with CsG metabolites. From all the molecules tested, PSC-833 and 280-446 peptolide were the strongest inhibitors. Our results indicate that modifications of CsA analogues at position 1 and 2 are critical for their interaction with P-gp and that CsA metabolites retain a portion of the inhibitory activity of the parent drug.
authors.affiliation: Laboratoire de Médecine Moléculaire, Université du Québec a Montréal, Hôpital Ste-Justine, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Demeule
authors.forename: A
authors.initials: A
authors.lastname: Laplante
authors.forename: A
authors.initials: A
authors.lastname: Sepehr-Araé
authors.forename: E
authors.initials: E
authors.lastname: Beaulieu
authors.forename: D
authors.initials: D
authors.lastname: Averill-Bates
authors.forename: R M
authors.initials: RM
authors.lastname: Wenger
authors.forename: R
authors.initials: R
authors.lastname: Béliveau
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000037:antagonists & inhibitors*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D016466:CHO Cells; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D006224:Cricetinae; D016572:Cyclosporine / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D003524:Cyclosporins / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D011992:Endosomes / Q000378:metabolism*; D008956:Models, Chemical; D019920:Photoaffinity Labels; D013997:Time Factors; D014700:Verapamil / Q000494:pharmacology; D014747:Vinblastine / Q000493:pharmacokinetics*
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D003524:Cyclosporins; D019920:Photoaffinity Labels; D014747:Vinblastine; D016572:Cyclosporine; D000255:Adenosine Triphosphate; D014700:Verapamil