title: Peptide transport by the multidrug resistance protein MRP1.
abstract: Small hydrophobic peptides were studied as possible substrates of the multidrug resistance protein (MRP)-1 (ABCC1) transmembrane transporter molecule. As observed earlier for P-glycoprotein- (Pgp; ABCB1) overexpressing cells, MRP1-overexpressing cells, including cells stably transfected with the MRP1 cDNA, showed distinct resistance to the cytotoxic peptide N-acetyl-Leu-Leu-norleucinal (ALLN). Resistance to this peptide and another toxic peptide derivative, which is based on a Thr-His-Thr-Nle-Glu-Gly backbone conjugated to butyl and benzyl groups (4A6), could be reversed by MRP1 inhibitors. The reduced toxicity of 4A6 in MRP1-overexpressing cells was found to be associated with lower accumulation of a fluorescein-labeled derivative of this peptide. Glutathione (GSH) depletion had a clear effect on resistance to ALLN but hardly affected 4A6 resistance. In a limited structure-activity study using peptides that are analogous to 4A6, MRP1-overexpressing cells were found to be resistant to these peptides as well. Remarkably, when selecting A2780 ovarian cancer cells for resistance to ALLN, even in the absence of Pgp blockers, resulting cell lines had up-regulated MRP1, rather than any of the other currently known multidrug resistance transporter molecules including Pgp, MRP2 (ABCC2), MRP3 (ABCC3), MRP5 (ABCCS), and the breast cancer resistance protein ABCG2. ALLN-resistant, MRP1-overexpressing cells were found to be cross-resistant to 4A6 and the classical multidrug resistance drugs doxorubicin, vincristine, and etoposide. This establishes MRP1 as a transporter for small hydrophobic peptides. More extensive structure-activity relationship studies should allow the identification of clinically useful peptide antagonists of MRP1.
authors: Department of Pathology, University Hospital Vrije Universiteit, Amsterdam, The Netherlands.
authors: M C
authors: MC
authors: de Jong
authors: J W
authors: JW
authors: Slootstra
authors: G L
authors: GL
authors: Scheffer
authors: A B
authors: AB
authors: Schroeijers
authors: W C
authors: WC
authors: Puijk
authors: R
authors: R
authors: Dinkelberg
authors: M
authors: M
authors: Kool
authors: H J
authors: HJ
authors: Broxterman
authors: R H
authors: RH
authors: Meloen
authors: R J
authors: RJ
authors: Scheper
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics / Q000633:toxicity; D000964:Antimetabolites, Antineoplastic / Q000493:pharmacokinetics / Q000633:toxicity; D001692:Biological Transport / Q000187:drug effects / Q000502:physiology; D019328:Buthionine Sulfoximine / Q000633:toxicity; D018432:Drug Resistance, Multiple / Q000502:physiology*; D019008:Drug Resistance, Neoplasm; D004357:Drug Synergism; D018922:HL-60 Cells; D006801:Humans; D007976:Leupeptins / Q000493:pharmacokinetics / Q000633:toxicity; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D009842:Oligopeptides / Q000493:pharmacokinetics* / Q000633:toxicity; D014407:Tumor Cells, Cultured; D014634:Valinomycin / Q000493:pharmacokinetics / Q000633:toxicity
chemical_list: D018528:ATP-Binding Cassette Transporters; D000900:Anti-Bacterial Agents; D000964:Antimetabolites, Antineoplastic; D019328:Buthionine Sulfoximine; D007976:Leupeptins; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D009842:Oligopeptides; D014634:Valinomycin; C000715087:ABCC2 protein, human; C063261:acetylleucyl-leucyl-norleucinal