title: Aristolochic acid I is a substrate of BCRP but not P-glycoprotein or MRP2.
abstract: BACKGROUND
  Aristolochic acid nephropathy is a severe kidney disease caused by the administration of aristolochic acid, which is widely existed in plants of the Aristolochiaceae family. Aristolochic acid I (AAI) is the main toxic component in aristolochic acid.
  
  
  OBJECTIVE
  The roles of intestinal efflux drug transporters in the transport of AAI are unclear. This study investigates the interaction between AAI and main intestinal efflux transporters.
  
  
  METHODS
  Firstly, bidirectional transport of AAI in Caco-2 cell monolayers was investigated. Then, MDCK-MDR1 (gene of P-glycoprotein (P-gp)), MDCK-MRP2 and LLC-PK1-BCRP cell lines were used for further investigation.
  
  
  RESULTS
  In this study, we observed that the efflux ratio of AAI in Caco-2 cell monolayers was 5.8, which indicated that efflux transporters might be involved in the transport of AAI. AAI did not inhibit Rho123 efflux by P-gp and calcein efflux by MRP2, and intracellular accumulation of AAI in P-gp or MRP2 overexpressing cells was not different from their parental cells. These results indicated that AAI was not a substrate of P-gp or MRP2. In contrast, intracellular accumulation of AAI in LLC-PK1-BCRP cells was significantly lower than in their parental cells. The presence of GF120918, a BCRP inhibitor, significantly increased AAI accumulation in BCRP overexpressing cells but not in their parental cells. In addition, bidirectional transport assay of AAI in LLC-PK1-BCRP monolayers showed that the net efflux ratios of AAI were 13.8, 8.0 and 7.0 at 20, 40 and 80 µM AAI, respectively, and decreased to 3.0, 1.9 and 2.0 by the addition of 10 µM GF120918.
  
  
  CONCLUSIONS
  These results indicated that AAI was a substrate of BCRP but not P-gp or MRP2.
authors.affiliation: Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China.
authors.forename: Liping
authors.initials: L
authors.lastname: Ma
authors.affiliation: Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China.
authors.forename: Yahong
authors.initials: Y
authors.lastname: Qin
authors.affiliation: Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China.
authors.forename: Zhuowei
authors.initials: Z
authors.lastname: Shen
authors.affiliation: Laboratory of Drug Metabolism and Pharmacokinetics, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China.
authors.forename: Huichang
authors.initials: H
authors.lastname: Bi
authors.affiliation: Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China.
authors.forename: Haiyong
authors.initials: H
authors.lastname: Hu
authors.affiliation: Laboratory of Drug Metabolism and Pharmacokinetics, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, China.
authors.forename: Min
authors.initials: M
authors.lastname: Huang
authors.affiliation: Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, 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, 866 Yuhangtang Road, Hangzhou 310058, China.
authors.forename: Lushan
authors.initials: L
authors.lastname: Yu
authors.affiliation: Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China.
authors.forename: Huidi
authors.initials: H
authors.lastname: Jiang
authors.affiliation: Laboratory of Pharmaceutical Analysis and Drug Metabolism, Zhejiang Province Key Laboratory of Anti-Cancer Drug Research, College of Pharmaceutical Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou 310058, China. Electronic address: zengsu@zju.edu.cn.
authors.forename: Su
authors.initials: S
authors.lastname: Zeng
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; D029065:Aristolochiaceae / Q000737:chemistry*; D034341:Aristolochic Acids / Q000302:isolation & purification / Q000493:pharmacokinetics*; D001692:Biological Transport; D018938:Caco-2 Cells; D004285:Dogs; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism*; D018374:LLC-PK1 Cells; D061985:Madin Darby Canine Kidney Cells; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000378:metabolism; D009363:Neoplasm Proteins / Q000378:metabolism*; D013552:Swine
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D034341:Aristolochic Acids; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D009363:Neoplasm Proteins; C000715087:ABCC2 protein, human; C116614:ABCG2 protein, human; C000228:aristolochic acid I
keywords: Aristolochic acid I; Aristolochic acid I (PubChem CID: 2236); BCRP; Calcein-AM (PubChem CID: 4126474); GF120918 (PubChem CID: 119373); Hoechst 33342 (PubChem CID: 1464); Indomethacin (PubChem CID: 3715); MK-571 (PubChem CID: 16760569); MRP2; P-glycoprotein; Rho123 (PubChem CID: 9929799); Verapamil hydrochloride (PubChem CID: 62969)