title: Effect of methotrexate treatment on expression levels of multidrug resistance protein 2, breast cancer resistance protein and organic anion transporters Oat1, Oat2 and Oat3 in rats.
abstract: The ATP binding cassette (ABC) transporters, multidrug resistance protein 2 (Mrp2; Abcc2) and breast cancer resistance protein (Bcrp; Abcg2), and organic anion transporters (Oats) mediate excretion of methotrexate (MTX) and many other drugs. However, it is not known whether MTX treatment leads to any changes in the expression of these transporters. We examined the effect of MTX treatment on expression of Mrp2, Bcrp and Oats in rats. MTX was single injected intraperitoneally at doses of 10, 50 and 150 mg/kg, and then Western blot analysis was performed. The levels of Mrp2, Oat1 and Oat2 on day 1 after the treatment showed no significant change. Four days after injection of 150 mg/kg MTX, the Mrp2 levels in the liver and ileum, but not in the kidney, were markedly down-regulated to 20 +/- 3.6% and 8.9 +/- 3.8% (mean +/- SEM) of controls, respectively. Renal Oat1 and Oat3 were also down-regulated to 56.4 +/- 4.3% (Oat1) and 54.3 +/- 5.5% (Oat3) of controls. These effects of MTX were almost recovered by leucovorin which rescues normal cells from MTX toxicity. MTX treatment also decreased mRNA levels of constitutive androstane receptor (CAR) and pregnane X receptor (PXR) to 65.5 +/- 17.9% and 59.6 +/- 14.5% of controls in the liver, respectively. MTX treatment has no apparent effect on expression levels of Bcrp, cytochrome P450 2B6 and 3A1. In conclusion, these data indicate that MTX treatment down-regulates expression levels of Mrp2, Oat1 and Oat3, and its effects are recovered by leucovorin.
authors.affiliation: Department of Clinical Pharmacy and Pharmacology, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima, 890-8520, Japan.
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Shibayama
authors.forename: Kazami
authors.initials: K
authors.lastname: Ushinohama
authors.forename: Ryuji
authors.initials: R
authors.lastname: Ikeda
authors.forename: Yoshimi
authors.initials: Y
authors.lastname: Yoshikawa
authors.forename: Toshiro
authors.initials: T
authors.lastname: Motoya
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Takeda
authors.forename: Katsushi
authors.initials: K
authors.lastname: Yamada
mesh_terms: D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000097:blood* / Q000235:genetics; D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology*; D015153:Blotting, Western; D015536:Down-Regulation; D006321:Heart / Q000187:drug effects / Q000502:physiology; D002955:Leucovorin / Q000494:pharmacology; D008297:Male; D008727:Methotrexate / Q000494:pharmacology*; D027362:Organic Anion Transport Protein 1 / Q000097:blood*; D029362:Organic Anion Transporters, Sodium-Independent / Q000097:blood*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014803:Vitamin B Complex / Q000494:pharmacology
chemical_list: D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; C423013:Abcc2 protein, rat; C489249:Abcg2 protein, rat; D000964:Antimetabolites, Antineoplastic; D027362:Organic Anion Transport Protein 1; D029362:Organic Anion Transporters, Sodium-Independent; D012333:RNA, Messenger; C421043:Slc22a6 protein, rat; C088800:Slc22a7 protein, rat; C114338:organic anion transport protein 3; D014803:Vitamin B Complex; D002955:Leucovorin; D008727:Methotrexate