title: Involvement of organic cation transporter 1 and CYP3A4 in retrorsine-induced toxicity.
abstract: Retrorsine (RTS) is a hepatotoxic pyrrolizidine alkaloid present in plants of the Senecio genus. The present study is aimed at clarifying the role of organic cation transporters (OCTs) in the liver disposition of RTS, and the coupling of OCT1 and cytochrome P450 (CYP) 3A4 in the hepatotoxicity of RTS. MDCK or LLC-PK1 cells stably expressing liver uptake or efflux transporters were used to investigate the interaction of RTS with these transporters. Primary cultured rat hepatocytes (PCRH) and double-transfected MDCK-hOCT1-CYP3A4 cells were used to determine the contribution of OCT1 and CYP3A4 to the toxicity of RTS. The results showed that RTS inhibited the OCT1-mediated 1-methyl-4-phenylpyridinium (MPP(+)) uptake in MDCK-hOCT1 cells with the IC50 of 2.25±0.30μM. The uptake of RTS in MDCK-hOCT1 cells and PCRH was significantly inhibited by OCT1 inhibitors, while hOCT3, human multidrug and toxin extrusion (hMATE) transporter 1, multidrug resistance 1 (MDR1), and breast cancer resistance protein (BCRP) showed weak or no obvious interaction with RTS. The toxic effect of RTS on the PCRH was attenuated by OCT1 inhibitors, quinidine and (+)-tetrahydropalmatine ((+)-THP). Compared to mock cells, MDCK-CYP3A4 cells showed a decrease in viability after being treated with RTS. Furthermore, RTS showed a more severe toxicity in the OCT1/CYP3A4 double-transfected cells compared to all other cells. Our data suggests that OCT1 mediates the liver-specific uptake of RTS, and plays an important role in RTS-induced hepatotoxicity together with CYP3A4. Consequently, the OCT1 inhibitors could be applied to protect the liver from the toxicity of RTS.
authors.affiliation: Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Meijuan
authors.initials: M
authors.lastname: Tu
authors.affiliation: Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Liping
authors.initials: L
authors.lastname: Li
authors.affiliation: Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Lei
authors.affiliation: Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Zhiyuan
authors.initials: Z
authors.lastname: Ma
authors.affiliation: Zhejiang Cancer Research Institute, Zhejiang Cancer Hospital, Hangzhou, China.
authors.forename: Zhongjian
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Siyuan
authors.initials: S
authors.lastname: Sun
authors.affiliation: Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Siyun
authors.initials: S
authors.lastname: Xu
authors.affiliation: Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhou
authors.affiliation: Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Su
authors.initials: S
authors.lastname: Zeng
authors.affiliation: Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China. Electronic address: hdjiang@zju.edu.cn.
authors.forename: Huidi
authors.initials: H
authors.lastname: Jiang
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000378:metabolism; D000818:Animals; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D056486:Chemical and Drug Induced Liver Injury / Q000473:pathology; D002851:Chromatography, High Pressure Liquid; D051544:Cytochrome P-450 CYP3A; D065692:Cytochrome P-450 CYP3A Inhibitors; D004285:Dogs; D022781:Hepatocytes / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D061985:Madin Darby Canine Kidney Cells; D013058:Mass Spectrometry; D009363:Neoplasm Proteins / Q000378:metabolism; D027702:Organic Cation Transporter 1 / Q000037:antagonists & inhibitors*; D016133:Polymerase Chain Reaction; D061251:Primary Cell Culture; D011763:Pyrrolizidine Alkaloids / Q000633:toxicity*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014162:Transfection
chemical_list: C116614:ABCG2 protein, human; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D065692:Cytochrome P-450 CYP3A Inhibitors; D009363:Neoplasm Proteins; D027702:Organic Cation Transporter 1; D011763:Pyrrolizidine Alkaloids; C465260:Cyp3a2 protein, rat; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human; C003300:retrorsine
keywords: CYP3A4; Double-transfected cells; Hepatotoxicity; Organic cation transporter 1; Retrorsine; Transporters