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Downregulation of Organic Anion Transporting Polypeptide (OATP) 1B1 Transport Function by Lysosomotropic Drug Chloroquine: Implication in OATP-Mediated Drug-Drug Interactions.

ABSTRACT: Organic anion transporting polypeptide (OATP) 1B1 mediates the hepatic uptake of many drugs including lipid-lowering statins. Decreased OATP1B1 transport activity is often associated with increased systemic exposure of statins and statin-induced myopathy. Antimalarial drug chloroquine (CQ) is also used for long-term treatment of rheumatoid arthritis and systemic lupus erythematosus. CQ is lysosomotropic and inhibits protein degradation in lysosomes. The current studies were designed to determine the effects of CQ on OATP1B1 protein degradation, OATP1B1-mediated transport in OATP1B1-overexpressing cell line, and statin uptake in human sandwich-cultured hepatocytes (SCH). Treatment with lysosome inhibitor CQ increased OATP1B1 total protein levels in HEK293-OATP1B1 cells and in human SCH as determined by OATP1B1 immunoblot. In HEK293-FLAG-tagged OATP1B1 stable cell line, co-immunofluorescence staining indicated that intracellular FLAG-OATP1B1 is colocalized with lysosomal associated membrane glycoprotein (LAMP)-2, a marker protein of late endosome/lysosome. Enlarged LAMP-2-positive vacuoles with FLAG-OATP1B1 protein retained inside were readily detected in CQ-treated cells, consistent with blocking lysosomal degradation of OATP1B1 by CQ. In HEK293-OATP1B1 cells, without pre-incubation, CQ concentrations up to 100 ?M did not affect OATP1B1-mediated [(3)H]E217G accumulation. However, pre-incubation with CQ at clinically relevant concentration(s) significantly decreased [(3)H]E217G and [(3)H]pitavastatin accumulation in HEK293-OATP1B1 cells and [(3)H]pitavastatin accumulation in human SCH. CQ pretreatment (25 ?M, 2 h) resulted in ?1.9-fold decrease in Vmax without affecting Km of OATP1B1-mediated [(3)H]E217G transport in HEK293-OATP1B1 cells. Pretreatment with monensin and bafilomycin A1, which also have lysosome inhibition activity, significantly decreased OATP1B1-mediated transport in HEK293-OATP1B1 cells. Pharmacoepidemiologic studies using data from the U.S. Food and Drug Administration Adverse Event Reporting System indicated that CQ plus pitavastatin, rosuvastatin, and pravastatin, which are minimally metabolized by the cytochrome P450 enzymes, led to higher myopathy risk than these statins alone. In summary, the present studies report novel findings that lysosome is involved in degradation of OATP1B1 protein and that pre-incubation with lysosomotropic drug CQ downregulates OATP1B1 transport activity. Our in vitro data in combination with pharmacoepidemiologic studies support that CQ has potential to cause OATP-mediated drug-drug interactions.

SUBMITTER: Alam K

PROVIDER: S-EPMC4970216 | biostudies-literature | 2016 Mar

REPOSITORIES: biostudies-literature

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Downregulation of Organic Anion Transporting Polypeptide (OATP) 1B1 Transport Function by Lysosomotropic Drug Chloroquine: Implication in OATP-Mediated Drug-Drug Interactions.

Alam Khondoker K Pahwa Sonia S Wang Xueying X Zhang Pengyue P Ding Kai K Abuznait Alaa H AH Li Lang L Yue Wei W

Molecular pharmaceutics 20160201 3

Organic anion transporting polypeptide (OATP) 1B1 mediates the hepatic uptake of many drugs including lipid-lowering statins. Decreased OATP1B1 transport activity is often associated with increased systemic exposure of statins and statin-induced myopathy. Antimalarial drug chloroquine (CQ) is also used for long-term treatment of rheumatoid arthritis and systemic lupus erythematosus. CQ is lysosomotropic and inhibits protein degradation in lysosomes. The current studies were designed to determine ...[more]

PMID: 26750564

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Project description:BACKGROUND AND PURPOSE:Intravenous glycyrrhizin, having anti-inflammatory and hepatoprotective properties, is incorporated into the management of liver diseases in China. This investigation was designed to elucidate the molecular mechanism underlying hepatobiliary excretion of glycyrrhizin and to investigate its potential for drug-drug interactions on organic anion-transporting polypeptide (OATP)1B. EXPERIMENTAL APPROACH:Human transporters mediating hepatobiliary excretion of glycyrrhizin were characterized at the cellular and vesicular levels and compared with rat hepatic transporters. The role of Oatp1b2 in glycyrrhizin's elimination and pharmacokinetics was evaluated in rats using the inhibitor rifampin. A physiologically based pharmacokinetic (PBPK) model for glycyrrhizin, incorporating transporter-mediated hepatobiliary excretion, was established and applied to predict potential drug-drug interactions related to glycyrrhizin in humans. KEY RESULTS:Hepatobiliary excretion of glycyrrhizin involved human OATP1B1/1B3 (Oatp1b2 in rats)-mediated hepatic uptake from blood and human multidrug resistance-associated protein (MRP)2/breast cancer resistance protein (ABCP)/bile salt export pump (BSEP)/multidrug resistance protein 1 (Mrp2/Abcp/Bsep in rats)-mediated hepatic efflux into bile. In rats, rifampin impaired hepatic uptake of glycyrrhizin significantly increasing its systemic exposure. Glomerular-filtration-based renal excretion of glycyrrhizin was slow due to extensive protein binding in plasma. Quantitative analysis using the PBPK model demonstrated that OATP1B1/1B3 have critical roles in the pharmacokinetics of glycyrrhizin, which is highly likely to be a victim of drug-drug interactions when co-administered with potent dual inhibitors of these transporters. CONCLUSIONS AND IMPLICATIONS:Transporter-mediated hepatobiliary excretion governs glycyrrhizin's elimination and pharmacokinetics. Understanding glycyrrhizin's potential drug-drug interactions on OATP1B1/1B3 should enhance the therapeutic outcome of glycyrrhizin-containing drug combinations on liver diseases.

Project description:OATP1B1 and OATP1B3 mediate hepatic uptake of many drugs (e.g., statins) and can mediate transporter-mediated drug-drug-interactions (DDIs). Bortezomib is the first-in-class proteasome inhibitor drug approved by the U. S. Food and Drug Administration for the treatment of multiple myeloma. The potential of bortezomib to cause OATP-mediated DDIs has not been assessed. The current study investigated the involvement of the ubiquitin-proteasome system (UPS) in OATP1B1 and OATP1B3 degradation and determined the effects of proteasome inhibitors on OATP1B1- and OATP1B3-mediated transport. Co-immunoprecipitation of FLAG-OATP1B1/1B3 and HA-ubiquitin was observed in human embryonic kidney (HEK) 293 cells co-transfected with FLAG-tagged OATP1B1/OATP1B3 and hemagglutinin (HA)-tagged ubiquitin, suggesting that OATP1B1 and OATP1B3 can be ubiquitin-modified. Although blocking proteasome activity by bortezomib treatment (50 nM, 7 h) increased the endogenous ubiquitin-conjugated FLAG-OATP1B1 and FLAG-OATP1B3 in HEK293-FLAG-OATP1B1 and-OATP1B3 cells, such treatment did not affect the total protein levels of OATP1B1 and OATP1B3, suggesting that the UPS plays a minor role in degradation of OATP1B1 and OATP1B3 under current constitutive conditions. Pretreatment with bortezomib (50-250 nM, 2-7 h) significantly decreased transport of [3H]CCK-8, a specific OATP1B3 substrate, in HEK293-OATP1B3 and human sandwich-cultured hepatocytes (SCH). However, bortezomib pretreatment had negligible effects on the transport of [3H]E217?G and [3H]pitavastatin, dual substrates of OATP1B1 and OATP1B3, in HEK293-OATP1B1/1B3 cells and/or human SCH. Compared with vehicle control treatment, bortezomib pretreatment significantly decreased the maximal transport velocity (Vmax) of OATP1B3-mediated transport of CCK-8 (92.25 ± 14.2 vs. 133.95 ± 15.5 pmol/mg protein/min) without affecting the affinity constant (Km) values. Treatment with other proteasome inhibitors MG132, epoxomicin, and carfilzomib also significantly decreased OATP1B3-mediated [3H]CCK-8 transport. In summary, the current studies for the first time report ubiquitination of OATP1B1 and OATP1B3 and the apparent substrate-dependent inhibitory effect of bortezomib on OATP1B3-mediated transport. The data suggest that bortezomib has a low risk of causing OATP-mediated DDIs.

Dataset Information

Downregulation of Organic Anion Transporting Polypeptide (OATP) 1B1 Transport Function by Lysosomotropic Drug Chloroquine: Implication in OATP-Mediated Drug-Drug Interactions.

Publications

Downregulation of Organic Anion Transporting Polypeptide (OATP) 1B1 Transport Function by Lysosomotropic Drug Chloroquine: Implication in OATP-Mediated Drug-Drug Interactions.

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