title: Interaction of oxazaphosphorines with multidrug resistance-associated protein 4 (MRP4).
abstract: Multidrug resistance-associated protein 4 (MRP4) is an organic anion efflux pump capable of transporting nucleoside, nucleotide analogs, and cyclic nucleotide. MRP4 could have an influence on the resistance and transport of the two oxazaphosphorines, cyclophosphamide (CP) and ifosfamide (IF). V/HepG2 (HepG2, hepatoma cells stably transfected with an empty vehicle plasmid) and MRP4/HepG2 (HepG2 cells stably expressing MRP4) were exposed to CP and IF in the absence or presence of various MRP4 inhibitors. HepG2 and HEK293 human kidney cells were also used to investigate the inducing potency of oxazaphosphorines on the MRP4 expression. In this study, insertion of MRP4 gene in HepG2 cells was found to confer significant resistance to CP and IF in the 48-h drug-exposure assays. In the presence of various MRP4 inhibitors, the resistance to CP and IF was then partially reversed. These indicate that CP and IF are highly possible substrates of MRP4. In addition, CP and clofibrate (CFB), a reported MRP4 inducer, in vivo significantly increased the MRP4 expression at both protein level and mRNA level in HEK293 cells at higher concentrations, while IF significantly decreased the MRP4 expression at mRNA level at lower concentration and had no effect at higher concentrations. However, all tested compounds (CP, IF, and CFB) did not change the MRP4 protein expression in HepG2 cells. CP and CFB are cell-specific and concentration-dependent MRP4 inducers. The finding may have implications in the CP- or IF-based chemotherapy.
authors.affiliation: Department of Pharmacy, Faculty of Science, National University of Singapore, 18 Science Drive 4, Singapore 117543, Singapore.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.forename: Ka-Yun
authors.initials: KY
authors.lastname: Ng
authors.forename: Paul C
authors.initials: PC
authors.lastname: Ho
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D001483:Base Sequence; D002460:Cell Line; D003520:Cyclophosphamide / Q000494:pharmacology; D017931:DNA Primers; D006801:Humans; D007069:Ifosfamide / Q000494:pharmacology; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics / Q000378:metabolism*; D017553:Phosphorus Compounds / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics
chemical_list: D000970:Antineoplastic Agents; D003520:Cyclophosphamide; D017931:DNA Primers; D007069:Ifosfamide; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D017553:Phosphorus Compounds; D012333:RNA, Messenger; C073492:ABCC4 protein, human
references.citation: Am J Pathol. 2000 Nov;157(5):1575-80
references.pmid: 11073816
references.citation: J Biol Chem. 2003 Jun 20;278(25):22908-17
references.pmid: 12682044
references.citation: World J Gastroenterol. 2005 May 14;11(18):2748-53
references.pmid: 15884115
references.citation: Toxicol Sci. 2008 Dec;106(2):319-28
references.pmid: 18757529
references.citation: Biochem Biophys Res Commun. 2004 Apr 23;317(1):46-53
references.pmid: 15047146
references.citation: Am J Clin Oncol. 1990 Apr;13(2):98-100
references.pmid: 2316488
references.citation: J Natl Cancer Inst. 2000 Dec 6;92(23):1934-40
references.pmid: 11106685
references.citation: Mol Cancer Ther. 2005 Apr;4(4):547-53
references.pmid: 15827327
references.citation: J Pharmacol Exp Ther. 2006 May;317(2):537-45
references.pmid: 16467456
references.citation: Am J Physiol Gastrointest Liver Physiol. 2006 Apr;290(4):G640-9
references.pmid: 16282361
references.citation: Drug Metab Dispos. 2007 Oct;35(10):1963-9
references.pmid: 17627974
references.citation: Cancer Res. 1987 Feb 15;47(4):936-42
references.pmid: 3802100
references.citation: J Clin Oncol. 2005 Feb 20;23(6):1161-8
references.pmid: 15718312
references.citation: J Natl Cancer Inst. 1994 Jul 6;86(13):975-82
references.pmid: 8007019
references.citation: Proc Natl Acad Sci U S A. 2003 Aug 5;100(16):9244-9
references.pmid: 12835412
references.citation: Biochem Pharmacol. 1995 May 26;49(11):1691-701
references.pmid: 7786310
references.citation: Am J Physiol Gastrointest Liver Physiol. 2008 Aug;295(2):G294-304
references.pmid: 18556419
references.citation: Toxicol Lett. 2001 Mar 31;120(1-3):51-7
references.pmid: 11323161
references.citation: Mol Cell Biol. 2004 Sep;24(17):7612-21
references.pmid: 15314169
references.citation: Toxicol Sci. 2004 Apr;78(2):229-40
references.pmid: 14976357
references.citation: Biochem J. 2002 Feb 1;361(Pt 3):497-503
references.pmid: 11802779
references.citation: Drug Metab Rev. 2005;37(4):611-703
references.pmid: 16393888
references.citation: J Biol Chem. 2004 May 21;279(21):22250-7
references.pmid: 15004017
references.citation: FASEB J. 1989 Dec;3(14):2583-92
references.pmid: 2574119
references.citation: Cancer Biochem Biophys. 1998 Jun;16(1-2):139-55
references.pmid: 9923973
references.citation: Methods. 2001 Dec;25(4):402-8
references.pmid: 11846609
references.citation: Ann N Y Acad Sci. 1996 Dec 27;804:252-65
references.pmid: 8993548
references.citation: Drug Metab Dispos. 2005 Jul;33(7):956-62
references.pmid: 15833929
references.citation: Endocr Relat Cancer. 2003 Mar;10(1):43-73
references.pmid: 12653670
references.citation: Br J Cancer. 1991 Jan;63(1):45-50
references.pmid: 1989664
references.citation: Hepatology. 2003 Aug;38(2):374-84
references.pmid: 12883481
references.citation: Br J Cancer. 1997;76(4):486-93
references.pmid: 9275026
references.citation: Drug Metab Dispos. 2003 Nov;31(11):1296-9
references.pmid: 14570758
references.citation: Mol Pharmacol. 2003 May;63(5):1094-103
references.pmid: 12695538
references.citation: Anticancer Res. 2004 Sep-Oct;24(5A):2931-9
references.pmid: 15517899