title: Induction of proteins involved in multidrug resistance (P-glycoprotein, MRP1, MRP2, LRP) and of CYP 3A4 by rifampicin in LLC-PK1 cells.
abstract: P-glycoprotein, multidrug resistance-related proteins (MRPs) and lung resistance-related protein (LRP) are involved in multidrug resistance in tumor cells but are also expressed in normal tissues. In the LLC-PK(1) tubular renal cell line, a 15-day treatment with 25 microM rifampicin significantly increased the mRNA levels of P-glycoprotein, MRP1, MRP2, LRP and cytochrome P450 3A4 (CYP 3A4). Western blot analysis confirmed a moderate increase in the expression of P-glycoprotein and MRP2, but not MRP1 also at the protein level. The intracellular uptake of doxorubicin was significantly lower in rifampicin pretreated cells. A pretreatment with 6-[82S,4R,6E)-4-methyl-2-(methylamino)-3-oxo-6-octenoic acid]cyclosporin D, valspodar (PSC 833), a specific inhibitor of P-glycoprotein, with (3-(3-(2-(7-chloro-2-quinidinyl)ethenyl-phenyl)((3-diimethyl amino-3oxo propyl)thio)methyl)thio)propanoic acid, sodium salt (MK-571), a specific inhibitor of MRP1, and with verapamil, that inhibits both proteins, significantly increased doxorubicin cell accumulation in rifampicin pretread cells. In rifampicin treated cells cultured on porous membranes, doxorubicin showed a polarized transport, that was reduced by a pretreatment with PSC 833. A chronic treatment with rifampicin induces the expression of transport proteins and of CYP 3A4 and could therefore alter the renal elimination kinetics of drugs that are their substrates.
authors.affiliation: Department of Biomedical Sciences, University of Trieste, Via L. Giorgieri 7, I-34127 Trieste, Italy.
authors.forename: Monica
authors.initials: M
authors.lastname: Magnarin
authors.forename: Manuela
authors.initials: M
authors.lastname: Morelli
authors.forename: Anna
authors.initials: A
authors.lastname: Rosati
authors.forename: Fiora
authors.initials: F
authors.lastname: Bartoli
authors.forename: Luigi
authors.initials: L
authors.lastname: Candussio
authors.forename: Tullio
authors.initials: T
authors.lastname: Giraldi
authors.forename: Giuliana
authors.initials: G
authors.lastname: Decorti
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000378:metabolism; D000904:Antibiotics, Antitubercular / Q000494:pharmacology*; D001693:Biological Transport, Active; D015153:Blotting, Western; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology; D002460:Cell Line; D051544:Cytochrome P-450 CYP3A; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis*; D017931:DNA Primers; D004317:Doxorubicin / Q000378:metabolism; D018432:Drug Resistance, Multiple / Q000235:genetics*; D004848:Epithelium / Q000378:metabolism; D007202:Indicators and Reagents; D018374:LLC-PK1 Cells; D011419:Propidium; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012293:Rifampin / Q000494:pharmacology*; D013552:Swine
chemical_list: D000900:Anti-Bacterial Agents; D000904:Antibiotics, Antitubercular; D017931:DNA Primers; D007202:Indicators and Reagents; D011419:Propidium; D004317:Doxorubicin; D003577:Cytochrome P-450 Enzyme System; C104464:CYP3A protein, human; D051544:Cytochrome P-450 CYP3A; D012293:Rifampin