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Ungvári O, Bakos É, Kovacsics D, Özvegy-Laczka C. The fluorescence-based competitive counterflow assay developed for organic anion transporting polypeptides 1A2, 1B1, 1B3 and 2B1 identifies pentamidine as a selective OATP1A2 substrate. FASEB J 2023; 37:e23223. [PMID: 37781971 DOI: 10.1096/fj.202300530rr] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 09/11/2023] [Accepted: 09/13/2023] [Indexed: 10/03/2023]
Abstract
Organic anion transporting polypeptides OATP1A2, OATP1B1, OATP1B3 and OATP2B1 are Na+ - and ATP-independent exchangers of large, organic compounds, encompassing structurally diverse xenobiotics, including various drugs. These OATPs influence intestinal absorption (OATP2B1), hepatic clearance (OATP1B1/3) and blood to brain penetration (OATP1A2, OATP2B1) of their drug substrates. Consequently, OATP-mediated drug or food interactions may lead to altered pharmacokinetics and toxicity. During drug development, investigation of hepatic OATP1B1 and OATP1B3 is recommended by international regulatory agencies. Most frequently, OATP-drug interactions are investigated in an indirect assay, i.e., by examining uptake inhibition of a radioactive or fluorescent probe. However, indirect assays do not distinguish between transported substrates and non-transported OATP inhibitors. To fill this hiatus, a novel assay, termed competitive counterflow (CCF) has been developed and has since been applied for several OATPs to differentiate between substrates and non-transported inhibitors. However, previous OATP CCF assays, with the exception of that for OATP1B1, used radioactive probes. In the current study, we demonstrate that sulforhodamine 101 or pyranine can be used as fluorescent probes in a CCF assay to identify transported substrates of OATP1A2, or OATPs 1B1, 1B3 and 2B1, respectively. With the help of the newly developed fluorescence-based CCF method, we identify the FDA-approved anti-protozoal drug, pentamidine as a unique substrate of OATP1A2. Furthermore, we confirm the selective, OATP1A2-mediated uptake of pentamidine in a cytotoxicity assay. Based on our results, OATP1A2 may be an important determinant of pentamidine transport through the blood-brain barrier.
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Affiliation(s)
- Orsolya Ungvári
- Institute of Enzymology, RCNS, Eötvös Loránd Research Network, Budapest, Hungary
- Doctoral School of Biology, Institute of Biology, Eötvös Loránd University, Budapest, Hungary
| | - Éva Bakos
- Institute of Enzymology, RCNS, Eötvös Loránd Research Network, Budapest, Hungary
| | - Daniella Kovacsics
- Institute of Enzymology, RCNS, Eötvös Loránd Research Network, Budapest, Hungary
| | - Csilla Özvegy-Laczka
- Institute of Enzymology, RCNS, Eötvös Loránd Research Network, Budapest, Hungary
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2
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Wannowius M, Karakus E, Aktürk Z, Breuer J, Geyer J. Role of the Sodium-Dependent Organic Anion Transporter (SOAT/SLC10A6) in Physiology and Pathophysiology. Int J Mol Sci 2023; 24:9926. [PMID: 37373074 DOI: 10.3390/ijms24129926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 06/02/2023] [Accepted: 06/03/2023] [Indexed: 06/29/2023] Open
Abstract
The sodium-dependent organic anion transporter (SOAT, gene symbol SLC10A6) specifically transports 3'- and 17'-monosulfated steroid hormones, such as estrone sulfate and dehydroepiandrosterone sulfate, into specific target cells. These biologically inactive sulfo-conjugated steroids occur in high concentrations in the blood circulation and serve as precursors for the intracrine formation of active estrogens and androgens that contribute to the overall regulation of steroids in many peripheral tissues. Although SOAT expression has been detected in several hormone-responsive peripheral tissues, its quantitative contribution to steroid sulfate uptake in different organs is still not completely clear. Given this fact, the present review provides a comprehensive overview of the current knowledge about the SOAT by summarizing all experimental findings obtained since its first cloning in 2004 and by processing SOAT/SLC10A6-related data from genome-wide protein and mRNA expression databases. In conclusion, despite a significantly increased understanding of the function and physiological significance of the SOAT over the past 20 years, further studies are needed to finally establish it as a potential drug target for endocrine-based therapy of steroid-responsive diseases such as hormone-dependent breast cancer.
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Affiliation(s)
- Marie Wannowius
- Institute of Pharmacology and Toxicology, Faculty of Veterinary Medicine, Biomedical Research Center Seltersberg (BFS), Justus Liebig University of Giessen, Schubertstr. 81, 35392 Giessen, Germany
| | - Emre Karakus
- Institute of Pharmacology and Toxicology, Faculty of Veterinary Medicine, Biomedical Research Center Seltersberg (BFS), Justus Liebig University of Giessen, Schubertstr. 81, 35392 Giessen, Germany
| | - Zekeriya Aktürk
- General Practice, Faculty of Medicine, University of Augsburg, 86159 Augsburg, Germany
| | - Janina Breuer
- Institute of Pharmacology and Toxicology, Faculty of Veterinary Medicine, Biomedical Research Center Seltersberg (BFS), Justus Liebig University of Giessen, Schubertstr. 81, 35392 Giessen, Germany
| | - Joachim Geyer
- Institute of Pharmacology and Toxicology, Faculty of Veterinary Medicine, Biomedical Research Center Seltersberg (BFS), Justus Liebig University of Giessen, Schubertstr. 81, 35392 Giessen, Germany
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3
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Schnegelberger RD, Steiert B, Sandoval PJ, Hagenbuch B. Using a competitive counterflow assay to identify novel cationic substrates of OATP1B1 and OATP1B3. Front Physiol 2022; 13:969363. [PMID: 36160869 PMCID: PMC9493024 DOI: 10.3389/fphys.2022.969363] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 08/08/2022] [Indexed: 12/15/2022] Open
Abstract
OATP1B1 and OATP1B3 are two drug transporters that mediate the uptake of multiple endo- and xenobiotics, including many drugs, into human hepatocytes. Numerous inhibitors have been identified, and for some of them, it is not clear whether they are also substrates. Historically radiolabeled substrates or LC-MS/MS methods were needed to test for transported substrates, both of which can be limiting in time and money. However, the competitive counterflow (CCF) assay originally described for OCT2 and, more recently, for OCT1, OATP2B1, and OATP1A2 does not require radiolabeled substrates or LC-MS/MS methods and, as a result, is a more cost-effective approach to identifying substrates of multidrug transporters. We used a CCF assay based on the stimulated efflux of the common model substrate estradiol-17β-glucuronide (E17βG) and tested 30 compounds for OATP1B1- and OATP1B3-mediated transport. Chinese Hamster Ovary (CHO) cells stably expressing OATP1B1 or OATP1B3 were preloaded with 10 nM [3H]-estradiol-17β-glucuronide. After the addition of known substrates like unlabeled estradiol-17β-glucuronide, estrone-3-sulfate, bromosulfophthalein, protoporphyrin X, rifampicin, and taurocholate to the outside of the preloaded CHO cells, we observed efflux of [3H]-estradiol-17β-glucuronide due to exchange with the added compounds. Of the tested 30 compounds, some organic cation transporter substrates like diphenhydramine, metformin, and salbutamol did not induce [3H]-estradiol-17β-glucuronide efflux, indicating that the two OATPs do not transport them. However, 22 (for OATP1B1) and 16 (for OATP1B3) of the tested compounds resulted in [3H]-estradiol-17β-glucuronide efflux, suggesting that they are OATP substrates. Among these compounds, we further tested clarithromycin, indomethacin, reserpine, and verapamil and confirmed that they are substrates of the two OATPs. These results demonstrate that the substrate spectrum of the well-characterized organic anion transporting polypeptides includes several organic cations. Furthermore, as for other drug uptake transporters, the CCF assay is an easy-to-use screening tool to identify novel OATP substrates.
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Hau RK, Tash JS, Georg GI, Wright SH, Cherrington NJ. Physiological Characterization of the Transporter-Mediated Uptake of the Reversible Male Contraceptive H2-Gamendazole Across the Blood-Testis Barrier. J Pharmacol Exp Ther 2022; 382:299-312. [PMID: 35779861 PMCID: PMC9426764 DOI: 10.1124/jpet.122.001195] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 06/14/2022] [Indexed: 11/22/2022] Open
Abstract
The blood-testis barrier (BTB) is formed by a tight network of Sertoli cells (SCs) to limit the movement of reproductive toxicants from the blood into the male genital tract. Transporters expressed at the basal membranes of SCs also influence the disposition of drugs across the BTB. The reversible, nonhormonal contraceptive, H2-gamendazole (H2-GMZ), is an indazole carboxylic acid analog that accumulates over 10 times more in the testes compared with other organs. However, the mechanism(s) by which H2-GMZ circumvents the BTB are unknown. This study describes the physiologic characteristics of the carrier-mediated process(es) that permit H2-GMZ and other analogs to penetrate SCs. Uptake studies were performed using an immortalized human SC line (hT-SerC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Uptake of H2-GMZ and four analogs followed Michaelis-Menten transport kinetics (one analog exhibited poor penetration). H2-GMZ uptake was strongly inhibited by indomethacin, diclofenac, MK-571, and several analogs. Moreover, H2-GMZ uptake was stimulated by an acidic extracellular pH, reduced at basic pHs, and independent of extracellular Na+, K+, or Cl- levels, which are intrinsic characteristics of OATP-mediated transport. Therefore, the characteristics of H2-GMZ transport suggest that one or more OATPs may be involved. However, endogenous transporter expression in wild-type Chinese hamster ovary (CHO), Madin-Darby canine kidney (MDCK), and human embryonic kidney-293 (HEK-293) cells limited the utility of heterologous transporter expression to identify a specific OATP transporter. Altogether, characterization of the transporters involved in the flux of H2-GMZ provides insight into the selectivity of drug disposition across the human BTB to understand and overcome the pharmacokinetic and pharmacodynamic difficulties presented by this barrier. SIGNIFICANCE STATEMENT: Despite major advancements in female contraceptives, male alternatives, including vasectomy, condom usage, and physical withdrawal, are antiquated and the widespread availability of nonhormonal, reversible chemical contraceptives is nonexistent. Indazole carboxylic acid analogs such as H2-GMZ are promising new reversible, antispermatogenic drugs that are highly effective in rodents. This study characterizes the carrier-mediated processes that permit H2-GMZ and other drugs to enter Sertoli cells and the observations made here will guide the development of drugs that effectively circumvent the BTB.
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Affiliation(s)
- Raymond K Hau
- Department of Pharmacology and Toxicology, College of Pharmacy (R.K.H., N.J.C.), and Department of Physiology, College of Medicine (S.H.W.), The University of Arizona, Tucson, Arizona; Department of Molecular and Integrative Physiology, KU School of Medicine, The University of Kansas Medical Center, Kansas City, Kansas (J.S.T.); Department of Medicinal Chemistry and Institute for Therapeutics Discovery and Development, College of Pharmacy, The University of Minnesota, Minneapolis, Minnesota (G.I.G.)
| | - Joseph S Tash
- Department of Pharmacology and Toxicology, College of Pharmacy (R.K.H., N.J.C.), and Department of Physiology, College of Medicine (S.H.W.), The University of Arizona, Tucson, Arizona; Department of Molecular and Integrative Physiology, KU School of Medicine, The University of Kansas Medical Center, Kansas City, Kansas (J.S.T.); Department of Medicinal Chemistry and Institute for Therapeutics Discovery and Development, College of Pharmacy, The University of Minnesota, Minneapolis, Minnesota (G.I.G.)
| | - Gunda I Georg
- Department of Pharmacology and Toxicology, College of Pharmacy (R.K.H., N.J.C.), and Department of Physiology, College of Medicine (S.H.W.), The University of Arizona, Tucson, Arizona; Department of Molecular and Integrative Physiology, KU School of Medicine, The University of Kansas Medical Center, Kansas City, Kansas (J.S.T.); Department of Medicinal Chemistry and Institute for Therapeutics Discovery and Development, College of Pharmacy, The University of Minnesota, Minneapolis, Minnesota (G.I.G.)
| | - Stephen H Wright
- Department of Pharmacology and Toxicology, College of Pharmacy (R.K.H., N.J.C.), and Department of Physiology, College of Medicine (S.H.W.), The University of Arizona, Tucson, Arizona; Department of Molecular and Integrative Physiology, KU School of Medicine, The University of Kansas Medical Center, Kansas City, Kansas (J.S.T.); Department of Medicinal Chemistry and Institute for Therapeutics Discovery and Development, College of Pharmacy, The University of Minnesota, Minneapolis, Minnesota (G.I.G.)
| | - Nathan J Cherrington
- Department of Pharmacology and Toxicology, College of Pharmacy (R.K.H., N.J.C.), and Department of Physiology, College of Medicine (S.H.W.), The University of Arizona, Tucson, Arizona; Department of Molecular and Integrative Physiology, KU School of Medicine, The University of Kansas Medical Center, Kansas City, Kansas (J.S.T.); Department of Medicinal Chemistry and Institute for Therapeutics Discovery and Development, College of Pharmacy, The University of Minnesota, Minneapolis, Minnesota (G.I.G.)
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Li TT, An JX, Xu JY, Tuo BG. Overview of organic anion transporters and organic anion transporter polypeptides and their roles in the liver. World J Clin Cases 2019; 7:3915-3933. [PMID: 31832394 PMCID: PMC6906560 DOI: 10.12998/wjcc.v7.i23.3915] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 11/20/2019] [Accepted: 11/26/2019] [Indexed: 02/05/2023] Open
Abstract
Organic anion transporters (OATs) and organic anion transporter polypeptides (OATPs) are classified within two SLC superfamilies, namely, the SLC22A superfamily and the SLCO superfamily (formerly the SLC21A family), respectively. They are expressed in many tissues, such as the liver and kidney, and mediate the absorption and excretion of many endogenous and exogenous substances, including various drugs. Most are composed of 12 transmembrane polypeptide chains with the C-terminus and the N-terminus located in the cell cytoplasm. OATs and OATPs are abundantly expressed in the liver, where they mainly promote the uptake of various endogenous substrates such as bile acids and various exogenous drugs such as antifibrotic and anticancer drugs. However, differences in the locations of glycosylation sites, phosphorylation sites, and amino acids in the OAT and OATP structures lead to different substrates being transported to the liver, which ultimately results in their different roles in the liver. To date, few articles have addressed these aspects of OAT and OATP structures, and we study further the similarities and differences in their structures, tissue distribution, substrates, and roles in liver diseases.
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Affiliation(s)
- Ting-Ting Li
- Department of Gastroenterology, Affiliated Hospital, Zunyi Medical University, Zunyi 563100, Guizhou Province, China
| | - Jia-Xing An
- Department of Gastroenterology, Affiliated Hospital, Zunyi Medical University, Zunyi 563100, Guizhou Province, China
| | - Jing-Yu Xu
- Department of Gastroenterology, Affiliated Hospital, Zunyi Medical University, Zunyi 563100, Guizhou Province, China
| | - Bi-Guang Tuo
- Department of Gastroenterology, Affiliated Hospital, Zunyi Medical University, Zunyi 563100, Guizhou Province, China
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6
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Amino-terminal region of human organic anion transporting polypeptide 1B1 dictates transporter stability and substrate interaction. Toxicol Appl Pharmacol 2019; 378:114642. [PMID: 31254566 DOI: 10.1016/j.taap.2019.114642] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 06/20/2019] [Accepted: 06/25/2019] [Indexed: 01/10/2023]
Abstract
Organic anion transporting polypeptides (OATPs) are key players of drug absorption, distribution and excretion due to their broad substrate specificity, wide tissue distribution and the involvement in drug-drug interaction. OATP1B1 is specifically localized at the basolateral membrane of human hepatocytes and serves a crucial role in the drug clearance from the body. Previous studies have shown that transmembrane domains (TMs) are essential for proper functions of OATPs. In the present study, site-directed mutagenesis was performed to study the TM1 and amino-terminus of OATP1B1. Two positively charged residues, K41 and K49, as well as a hydrophobic residue I46, in TM1 were identified to be important for the proper function of the transporter. K41A and K49A exhibited altered Km value at the high and low affinity binding sites of estrone-3- sulfate (ES), respectively; while alanine substitution of I46 showed altered Km and Vmax values for both binding components of ES. Additional replacement of K41 revealed that the positively charged property at this position is important for maintaining OATP1B1 protein level and function; while the specific side-group structure of lysine at position 49 is irreplaceable for the transporter activity. Conservative replacement of I46 with leucine also recovered the function of the transporter. In addition, studies of the amino-terminus of OATP1B1 revealed that residues ranging from 19 to 27 are essential for protein stability and substrate interaction. Therefore, the amino-terminal region, which includes TM1 and the amino-terminus of OATP1B1, is important for proper function of the membrane protein.
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7
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Alam K, Farasyn T, Ding K, Yue W. Characterization of Liver- and Cancer-type-Organic Anion Transporting Polypeptide (OATP) 1B3 Messenger RNA Expression in Normal and Cancerous Human Tissues. Drug Metab Lett 2019; 12:24-32. [PMID: 29577869 DOI: 10.2174/1872312812666180326110146] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 03/08/2018] [Accepted: 03/10/2018] [Indexed: 01/30/2023]
Abstract
BACKGROUND Membrane transport protein organic anion transporting polypeptide (OATP) 1B3 mediates the cellular uptake of many clinically important drugs including anti-cancer drugs (e.g., paclitaxel). In addition to the well-recognized hepatic expression and function of OATP1B3 [herein named liver-type (Lt) OATP1B3], OATP1B3 also expresses in cancers and has been postulated to play a role in cancer therapy, presumably by facilitating the influx of anti-cancer drugs. Recently, a cancer type (Ct)-OATP1B3 mRNA variant was identified in colon and lung cancer tissues, which encodes truncated Ct-OATP1B3 with negligible transport activity. Other than in colon and lung cancers, reports on mRNA expression of OATP1B3 in other cancers cannot distinguish between the Ltand Ct-OATP1B3. OBJECTIVE The current studies were designed to characterize the expression of Lt- and Ct-OATP1B3 mRNA in ovarian, prostate, bladder, breast, and lung tissues. METHODS Lt- and Ct-OATP1B3 isoform-specific PCR primers were utilized to determine the mRNA levels of Lt- and Ct-OATP1B3, respectively. An expression vector expressing green fluorescent protein (GFP)-tagged Lt-OATP1B3 was transiently transfected into the ovarian cancer cell line SKOV3. Confocal live-cell microscopy was utilized to determine the localization of GFP-Lt-OATP1B3 in SKOV3 cells. RESULTS For the first time, Lt-OATP1B3 mRNA was detected in ovarian, prostate, bladder and breast cancers. The localization of GFP-Lt-OATP1B3 on the plasma membrane of SKOV3 cells after transient transfection was readily detected by confocal microscopy. CONCLUSION Our findings are supportive of the potential role of Lt-OATP1B3 in cancer cells.
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Affiliation(s)
- Khondoker Alam
- Department of Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Taleah Farasyn
- Department of Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Kai Ding
- Department of Biostatistics and Epidemiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Wei Yue
- Department of Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
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Xiang Z, Li W, Wang L, Yi J, Chen K, Hong M. Identification of a NF κB Inhibition Site on the Proximal Promoter Region of Human Organic Anion Transporting Polypeptide 1A2 Coding Gene SLCO1A2. Drug Metab Dispos 2018; 46:643-651. [PMID: 29549185 DOI: 10.1124/dmd.117.078832] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Accepted: 03/12/2018] [Indexed: 01/21/2023] Open
Abstract
Organic anion transporting polypeptides (OATPs; gene symbol SLCO) are membrane transporters that mediate the transport of wide ranges of compounds. The expression of different OATP members has been reported in the kidney, liver, placenta, brain, and intestine. Because of their broad substrate spectra and wide distribution within the human body, these transporters have been proposed to play key roles in the influx transport of many oral drugs. Inflammation is known to regulate the expression and functions of many drug-metabolizing enzymes and drug transporters. As a proinflammatory cytokine, tumor necrosis factor-α (TNFα) has been shown to affect the expression of different drug transporters, including OATP family members. In the present study, a putative nuclear factor-κB (NFκB) binding site ranging from -1845 to -1836 was identified at the proximal promoter region of OATP1A2 coding gene SLCO1A2 Electrophoretic mobility shift assays and chromatin immunoprecipitation showed that nuclear extracts from both breast cancer cell MCF7 and liver cancer cell HepG2 interacted with an oligonucleotide probe containing the putative NFκB binding site and that the DNA-protein complexes contained both p65 and p50 subunits of NFκB. Further study revealed that the binding site may be responsible in part for the suppression effect of TNFα toward SLCO1A2 expression because the treatment of TNFα significantly increased. Treatment of TNFα significantly increased formation of the DNA-protein complexes and mutations at essential bases of the putative NFκB binding site abolished responsiveness to the TNFα neutralizing antibody, suggesting that the binding site may be responsible in part for the suppression effect of TNFα towars SLCO1A2 expression.
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Affiliation(s)
- Zhaojian Xiang
- College of Life Sciences (Z.X., W.L., L.W., J.Y., K.C., M.H.) and Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms (M.H.), South China Agricultural University, Guangzhou, People's Republic of China
| | - Weike Li
- College of Life Sciences (Z.X., W.L., L.W., J.Y., K.C., M.H.) and Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms (M.H.), South China Agricultural University, Guangzhou, People's Republic of China
| | - Lixue Wang
- College of Life Sciences (Z.X., W.L., L.W., J.Y., K.C., M.H.) and Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms (M.H.), South China Agricultural University, Guangzhou, People's Republic of China
| | - Jicai Yi
- College of Life Sciences (Z.X., W.L., L.W., J.Y., K.C., M.H.) and Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms (M.H.), South China Agricultural University, Guangzhou, People's Republic of China
| | - Kaiwen Chen
- College of Life Sciences (Z.X., W.L., L.W., J.Y., K.C., M.H.) and Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms (M.H.), South China Agricultural University, Guangzhou, People's Republic of China
| | - Mei Hong
- College of Life Sciences (Z.X., W.L., L.W., J.Y., K.C., M.H.) and Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms (M.H.), South China Agricultural University, Guangzhou, People's Republic of China
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9
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Geyer J, Bakhaus K, Bernhardt R, Blaschka C, Dezhkam Y, Fietz D, Grosser G, Hartmann K, Hartmann MF, Neunzig J, Papadopoulos D, Sánchez-Guijo A, Scheiner-Bobis G, Schuler G, Shihan M, Wrenzycki C, Wudy SA, Bergmann M. The role of sulfated steroid hormones in reproductive processes. J Steroid Biochem Mol Biol 2017; 172:207-221. [PMID: 27392637 DOI: 10.1016/j.jsbmb.2016.07.002] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 07/04/2016] [Indexed: 10/21/2022]
Abstract
Sulfated steroid hormones, such as dehydroepiandrosterone sulfate or estrone-3-sulfate, have long been regarded as inactive metabolites as they cannot activate classical steroid receptors. Some of them are present in the blood circulation at quite high concentrations, but generally sulfated steroids exhibit low membrane permeation due to their hydrophilic properties. However, sulfated steroid hormones can actively be imported into specific target cells via uptake carriers, such as the sodium-dependent organic anion transporter SOAT, and, after hydrolysis by the steroid sulfatase (so-called sulfatase pathway), contribute to the overall regulation of steroid responsive organs. To investigate the biological significance of sulfated steroid hormones for reproductive processes in humans and animals, the research group "Sulfated Steroids in Reproduction" was established by the German Research Foundation DFG (FOR1369). Projects of this group deal with transport of sulfated steroids, sulfation of free steroids, desulfation by the steroid sulfatase, effects of sulfated steroids on steroid biosynthesis and membrane receptors as well as MS-based profiling of sulfated steroids in biological samples. This review and concept paper presents key findings from all these projects and provides a broad overview over the current research on sulfated steroid hormones in the field of reproduction.
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Affiliation(s)
- Joachim Geyer
- Institute of Pharmacology and Toxicology, Justus Liebig University, Giessen, Germany.
| | - Katharina Bakhaus
- Institute of Pharmacology and Toxicology, Justus Liebig University, Giessen, Germany
| | - Rita Bernhardt
- Institute of Biochemistry, Saarland University, Saarbrücken, Germany
| | - Carina Blaschka
- Veterinary Clinic for Obstetrics, Gynecology and Andrology, Justus Liebig University, Giessen, Germany
| | - Yaser Dezhkam
- Veterinary Clinic for Obstetrics, Gynecology and Andrology, Justus Liebig University, Giessen, Germany
| | - Daniela Fietz
- Department of Veterinary Anatomy, Histology and Embryology, Justus Liebig University, Giessen, Germany
| | - Gary Grosser
- Institute of Pharmacology and Toxicology, Justus Liebig University, Giessen, Germany
| | - Katja Hartmann
- Department of Veterinary Anatomy, Histology and Embryology, Justus Liebig University, Giessen, Germany
| | - Michaela F Hartmann
- Steroid Research & Mass Spectrometry Unit, Laboratory for Translational Hormone Analytics, Pediatric Endocrinology & Diabetology, Center of Child and Adolescent Medicine, Justus Liebig University, Giessen, Germany
| | - Jens Neunzig
- Institute of Biochemistry, Saarland University, Saarbrücken, Germany
| | - Dimitrios Papadopoulos
- Institute of Veterinary Physiology and Biochemistry, Justus Liebig University, Giessen, Germany
| | - Alberto Sánchez-Guijo
- Steroid Research & Mass Spectrometry Unit, Laboratory for Translational Hormone Analytics, Pediatric Endocrinology & Diabetology, Center of Child and Adolescent Medicine, Justus Liebig University, Giessen, Germany
| | - Georgios Scheiner-Bobis
- Institute of Veterinary Physiology and Biochemistry, Justus Liebig University, Giessen, Germany
| | - Gerhard Schuler
- Veterinary Clinic for Obstetrics, Gynecology and Andrology, Justus Liebig University, Giessen, Germany
| | - Mazen Shihan
- Institute of Veterinary Physiology and Biochemistry, Justus Liebig University, Giessen, Germany
| | - Christine Wrenzycki
- Veterinary Clinic for Obstetrics, Gynecology and Andrology, Justus Liebig University, Giessen, Germany
| | - Stefan A Wudy
- Steroid Research & Mass Spectrometry Unit, Laboratory for Translational Hormone Analytics, Pediatric Endocrinology & Diabetology, Center of Child and Adolescent Medicine, Justus Liebig University, Giessen, Germany
| | - Martin Bergmann
- Department of Veterinary Anatomy, Histology and Embryology, Justus Liebig University, Giessen, Germany
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Abstract
Transporters in proximal renal tubules contribute to the disposition of numerous drugs. Furthermore, the molecular mechanisms of tubular secretion have been progressively elucidated during the past decades. Organic anions tend to be secreted by the transport proteins OAT1, OAT3 and OATP4C1 on the basolateral side of tubular cells, and multidrug resistance protein (MRP) 2, MRP4, OATP1A2 and breast cancer resistance protein (BCRP) on the apical side. Organic cations are secreted by organic cation transporter (OCT) 2 on the basolateral side, and multidrug and toxic compound extrusion (MATE) proteins MATE1, MATE2/2-K, P-glycoprotein, organic cation and carnitine transporter (OCTN) 1 and OCTN2 on the apical side. Significant drug-drug interactions (DDIs) may affect any of these transporters, altering the clearance and, consequently, the efficacy and/or toxicity of substrate drugs. Interactions at the level of basolateral transporters typically decrease the clearance of the victim drug, causing higher systemic exposure. Interactions at the apical level can also lower drug clearance, but may be associated with higher renal toxicity, due to intracellular accumulation. Whereas the importance of glomerular filtration in drug disposition is largely appreciated among clinicians, DDIs involving renal transporters are less well recognized. This review summarizes current knowledge on the roles, quantitative importance and clinical relevance of these transporters in drug therapy. It proposes an approach based on substrate-inhibitor associations for predicting potential tubular-based DDIs and preventing their adverse consequences. We provide a comprehensive list of known drug interactions with renally-expressed transporters. While many of these interactions have limited clinical consequences, some involving high-risk drugs (e.g. methotrexate) definitely deserve the attention of prescribers.
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Affiliation(s)
- Anton Ivanyuk
- Division of Clinical Pharmacology, Lausanne University Hospital (CHUV), Bugnon 17, 1011, Lausanne, Switzerland.
| | - Françoise Livio
- Division of Clinical Pharmacology, Lausanne University Hospital (CHUV), Bugnon 17, 1011, Lausanne, Switzerland
| | - Jérôme Biollaz
- Division of Clinical Pharmacology, Lausanne University Hospital (CHUV), Bugnon 17, 1011, Lausanne, Switzerland
| | - Thierry Buclin
- Division of Clinical Pharmacology, Lausanne University Hospital (CHUV), Bugnon 17, 1011, Lausanne, Switzerland
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11
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eUnaG: a new ligand-inducible fluorescent reporter to detect drug transporter activity in live cells. Sci Rep 2017; 7:41619. [PMID: 28176814 PMCID: PMC5296874 DOI: 10.1038/srep41619] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 12/22/2016] [Indexed: 01/18/2023] Open
Abstract
The absorption, distribution, metabolism and excretion (ADME) of metabolites and toxic organic solutes are orchestrated by the ATP-binding cassette (ABC) transporters and the organic solute carrier family (SLC) proteins. A large number of ABC and SLC transpoters exist; however, only a small number have been well characterized. To facilitate the analysis of these transporters, which is important for drug safety and physiological studies, we developed a sensitive genetically encoded bilirubin (BR)-inducible fluorescence sensor (eUnaG) to detect transporter-coupled influx/efflux of organic compounds. This sensor can be used in live cells to measure transporter activity, as excretion of BR depends on ABC and SLC transporters. Applying eUnaG in functional RNAi screens, we characterize l(2)03659 as a Drosophila multidrug resistant-associated ABC transporter.
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12
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13
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Kulkarni P, Korzekwa K, Nagar S. Intracellular Unbound Atorvastatin Concentrations in the Presence of Metabolism and Transport. J Pharmacol Exp Ther 2016; 359:26-36. [PMID: 27451408 DOI: 10.1124/jpet.116.235689] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 07/20/2016] [Indexed: 12/26/2022] Open
Abstract
Accurate prediction of drug target activity and rational dosing regimen design require knowledge of drug concentrations at the target. It is important to understand the impact of processes such as membrane permeability, partitioning, and active transport on intracellular drug concentrations. The present study aimed to predict intracellular unbound atorvastatin concentrations and characterize the effect of enzyme-transporter interplay on these concentrations. Single-pass liver perfusion studies were conducted in rats using atorvastatin (ATV, 1 µM) alone at 4°C and at 37°C in presence of rifampin (RIF, 20 µM) and 1-aminobenzotriazole (ABT, 1 mM), separately and in combination. The unbound intracellular ATV concentration was predicted with a five-compartment explicit membrane model using the parameterized diffusional influx clearance, active basolateral uptake clearance, and metabolic clearance. Chemical inhibition of uptake and metabolism at 37°C proved to be better controls relative to studies at 4°C. The predicted unbound intracellular concentration at the end of the 50-minute perfusion in the +ABT , +ABT+RIF, and the ATV-only groups was 6.5 µM, 0.58 µM, and 5.14 µM, respectively. The predicted total liver concentrations and amount recovered in bile were within 0.94-1.3 fold of the observed value in all groups. The fold difference in total liver concentration did not always extrapolate to the fold difference in predicted unbound concentration across groups. Together, these results support the use of compartmental modeling to predict intracellular concentrations in dynamic organ-based systems. These predictions can provide insight into the role of uptake transporters and metabolizing enzymes in determining drug tissue concentrations.
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Affiliation(s)
- Priyanka Kulkarni
- Department of Pharmaceutical Sciences, Temple University School of Pharmacy, Philadelphia, Pennsylvania
| | - Kenneth Korzekwa
- Department of Pharmaceutical Sciences, Temple University School of Pharmacy, Philadelphia, Pennsylvania
| | - Swati Nagar
- Department of Pharmaceutical Sciences, Temple University School of Pharmacy, Philadelphia, Pennsylvania
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14
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Hong W, Wu Z, Fang Z, Huang J, Huang H, Hong M. Amino Acid Residues in the Putative Transmembrane Domain 11 of Human Organic Anion Transporting Polypeptide 1B1 Dictate Transporter Substrate Binding, Stability, and Trafficking. Mol Pharm 2015; 12:4270-6. [DOI: 10.1021/acs.molpharmaceut.5b00466] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Weifang Hong
- College
of Life Science, South China Agricultural University, Guangzhou, China
| | - Zhixuan Wu
- College
of Life Science, South China Agricultural University, Guangzhou, China
| | - Zihui Fang
- College
of Life Science, South China Agricultural University, Guangzhou, China
| | - Jiujiu Huang
- College
of Life Science, South China Agricultural University, Guangzhou, China
| | - Hong Huang
- School
of Information, University of South Florida, Tampa, Florida 33620, United States
| | - Mei Hong
- College
of Life Science, South China Agricultural University, Guangzhou, China
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15
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Visentin M, Stieger B, Merz M, Kullak-Ublick GA. Octreotide inhibits the bilirubin carriers organic anion transporting polypeptides 1B1 and 1B3 and the multidrug resistance-associated protein 2. J Pharmacol Exp Ther 2015; 355:145-51. [PMID: 26330539 DOI: 10.1124/jpet.115.227546] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 08/31/2015] [Indexed: 08/30/2023] Open
Abstract
The somatostatin analog octreotide can lead to hyperbilirubinemia without evidence of liver injury. Here we investigate whether octreotide inhibits the main sinusoidal/canalicular bilirubin carriers and whether it is a transport substrate. Octreotide showed the most potent inhibitory effect toward OATP1B1-mediated transport and weaker inhibition for OATP1B3- and MRP2-mediated transport. Octreotide had no effect on OATP2B1-mediated transport. Octreotide inhibited [(3)H]estradiol-17-β-glucuronide (E17βG) influx mediated by OATP1B1, 1B3, and multidrug resistance-associated protein 2 (MRP2) in a concentration-dependent manner, and the IC50 values were computed to be 23 μM (95% confidence interval [CI] 18-29), 68 μM (95% CI 50-91), and 116.6 μM (95% CI 74.5-182.4), respectively. The interaction between octreotide and OATP1B1 was further studied. Inhibition of [(3)H]E17βG OATP1B1-mediated transport was purely competitive with no changes in maximum transport capacity (Vmax) and a twofold Km increase when the influx kinetics of [(3)H]E17βG were measured in the presence of octreotide (8.8 ± 3.1 versus 4.4 ± 1.2 μM, P = 0.03). The inhibition constant (Ki) of octreotide for the transport of [(3)H]E17βG was calculated at 33.5 ± 5.5 μM. Uptake of radiolabeled octreotide by OATP1B1-CHO cells was higher than in wild-type CHO cells and nonlabeled octreotide at the extracellular compartment was able to trans-stimulate the OATP1B1-mediated efflux of intracellular [(3)H]E17βG, suggesting that octreotide is a substrate of OATP1B1. In summary, this study shows interaction of octreotide on the human hepatocellular bilirubin transporters OATP1B1, OATP1B3, and MRP2, notably OATP1B1. These findings are in line with the clinical observation that a fraction of patients under treatment with octreotide exhibit hyperbilirubinemia.
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Affiliation(s)
- Michele Visentin
- Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, Switzerland (M.V., B.S., G.A.K.-U.); and Discovery and Investigative Safety, Novartis Institutes for BioMedical Research, Basel, Switzerland (M.M., G.A.K.-U.)
| | - Bruno Stieger
- Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, Switzerland (M.V., B.S., G.A.K.-U.); and Discovery and Investigative Safety, Novartis Institutes for BioMedical Research, Basel, Switzerland (M.M., G.A.K.-U.)
| | - Michael Merz
- Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, Switzerland (M.V., B.S., G.A.K.-U.); and Discovery and Investigative Safety, Novartis Institutes for BioMedical Research, Basel, Switzerland (M.M., G.A.K.-U.)
| | - Gerd A Kullak-Ublick
- Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, Switzerland (M.V., B.S., G.A.K.-U.); and Discovery and Investigative Safety, Novartis Institutes for BioMedical Research, Basel, Switzerland (M.M., G.A.K.-U.)
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16
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Abstract
Organic anion-transporting polypeptides or OATPs are central transporters in the disposition of drugs and other xenobiotics. In addition, they mediate transport of a wide variety of endogenous substrates. The critical role of OATPs in drug disposition has spurred research both in academia and in the pharmaceutical industry. Translational aspects with clinical questions are the focus in academia, while the pharmaceutical industry tries to define and understand the role these transporters play in pharmacotherapy. The present overview summarizes our knowledge on the interaction of food constituents with OATPs and on the OATP transport mechanisms. Further, it gives an update on the available information on the structure-function relationship of the OATPs and, finally, covers the transcriptional and posttranscriptional regulation of OATPs.
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Affiliation(s)
- Bruno Stieger
- Department of Clinical Pharmacology and Toxicology, University Hospital, Zürich, Switzerland.
| | - Bruno Hagenbuch
- Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, Kansas, USA
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17
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Steiner K, Hagenbuch B, Dietrich DR. Molecular cloning and functional characterization of a rainbow trout liver Oatp. Toxicol Appl Pharmacol 2014; 280:534-42. [PMID: 25218291 DOI: 10.1016/j.taap.2014.08.031] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 08/25/2014] [Accepted: 08/29/2014] [Indexed: 01/06/2023]
Abstract
Cyanobacterial blooms have an impact on the aquatic ecosystem due to the production of toxins (e.g. microcystins, MCs), which constrain fish health or even cause fish death. However the toxicokinetics of the most abundant toxin, microcystin-LR (MC-LR), are not yet fully understood. To investigate the uptake mechanism, the novel Oatp1d1 in rainbow trout (rtOatp1d1) was cloned, identified and characterized. The cDNA isolated from a clone library consisted of 2772bp containing a 2115bp open reading frame coding for a 705 aa protein with an approximate molecular mass of 80kDa. This fish specific transporter belongs to the OATP1 family and has most likely evolved from a common ancestor of OATP1C1. Real time PCR analysis showed that rtOatp1d1 is predominantly expressed in the liver, followed by the brain while expression in other organs was not detectable. Transient transfection in HEK293 cells was used for further characterization. Like its human homologues OATP1A1, OATP1B1 and OATP1B3, rtOatp1d1 displayed multi-specific transport including endogenous and xenobiotic substrates. Kinetic analyses revealed a Km value of 13.9μM and 13.4μM for estrone-3-sulfate and methotrexate, respectively and a rather low affinity for taurocholate with a Km value of 103μM. Furthermore, it was confirmed that rtOatp1d1 is a MC-LR transporter and therefore most likely plays a key role in the susceptibility of rainbow trout to MC intoxications.
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Affiliation(s)
- Konstanze Steiner
- University of Konstanz, Human- and Environmental Toxicology, 78464 Konstanz, Germany.
| | - Bruno Hagenbuch
- Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City 66160, KS, USA.
| | - Daniel R Dietrich
- University of Konstanz, Human- and Environmental Toxicology, 78464 Konstanz, Germany.
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18
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Xiao Y, Deng J, Liu X, Huang J, Sun Y, Dai R, Hong M. Different Binding Sites of Bovine Organic Anion–Transporting Polypeptide1a2 Are Involved in the Transport of Different Fluoroquinolones. Drug Metab Dispos 2014; 42:1261-7. [DOI: 10.1124/dmd.114.057448] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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19
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Heger M, van Golen RF, Broekgaarden M, Michel MC. The molecular basis for the pharmacokinetics and pharmacodynamics of curcumin and its metabolites in relation to cancer. Pharmacol Rev 2013; 66:222-307. [PMID: 24368738 DOI: 10.1124/pr.110.004044] [Citation(s) in RCA: 346] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
This review addresses the oncopharmacological properties of curcumin at the molecular level. First, the interactions between curcumin and its molecular targets are addressed on the basis of curcumin's distinct chemical properties, which include H-bond donating and accepting capacity of the β-dicarbonyl moiety and the phenylic hydroxyl groups, H-bond accepting capacity of the methoxy ethers, multivalent metal and nonmetal cation binding properties, high partition coefficient, rotamerization around multiple C-C bonds, and the ability to act as a Michael acceptor. Next, the in vitro chemical stability of curcumin is elaborated in the context of its susceptibility to photochemical and chemical modification and degradation (e.g., alkaline hydrolysis). Specific modification and degradatory pathways are provided, which mainly entail radical-based intermediates, and the in vitro catabolites are identified. The implications of curcumin's (photo)chemical instability are addressed in light of pharmaceutical curcumin preparations, the use of curcumin analogues, and implementation of nanoparticulate drug delivery systems. Furthermore, the pharmacokinetics of curcumin and its most important degradation products are detailed in light of curcumin's poor bioavailability. Particular emphasis is placed on xenobiotic phase I and II metabolism as well as excretion of curcumin in the intestines (first pass), the liver (second pass), and other organs in addition to the pharmacokinetics of curcumin metabolites and their systemic clearance. Lastly, a summary is provided of the clinical pharmacodynamics of curcumin followed by a detailed account of curcumin's direct molecular targets, whereby the phenotypical/biological changes induced in cancer cells upon completion of the curcumin-triggered signaling cascade(s) are addressed in the framework of the hallmarks of cancer. The direct molecular targets include the ErbB family of receptors, protein kinase C, enzymes involved in prostaglandin synthesis, vitamin D receptor, and DNA.
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Affiliation(s)
- Michal Heger
- Department of Experimental Surgery, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105AZ Amsterdam, The Netherlands.
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20
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Hagenbuch B, Stieger B. The SLCO (former SLC21) superfamily of transporters. Mol Aspects Med 2013; 34:396-412. [PMID: 23506880 DOI: 10.1016/j.mam.2012.10.009] [Citation(s) in RCA: 260] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Accepted: 09/19/2012] [Indexed: 01/04/2023]
Abstract
The members of the organic anion transporting polypeptide superfamily (OATPs) are classified within the SLCO solute carrier family. All functionally well characterized members are predicted to have 12 transmembrane domains and are sodium-independent transport systems that mediate the transport of a broad range of endo- as well as xenobiotics. Substrates are mainly amphipathic organic anions with a molecular weight of more than 300Da, but some of the known transported substrates are also neutral or even positively charged. Among the well characterized substrates are numerous drugs including statins, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, antibiotics, antihistaminics, antihypertensives and anticancer drugs. Based on their amino acid sequence identities, the different OATPs cluster into families (in general with more than 40% amino acid sequence identity) and subfamilies (more than 60% amino acid identity). With the sequencing of genomes from different species and the computerized prediction of encoded proteins more than 300 OATPs can be found in the databases, however only a fraction of them have been identified in humans, rodents, and some additional species important for pharmaceutical research like the rhesus monkey (Macaca mulatta), the dog (Canis lupus familiaris) and the pig (Sus scrofa). These OATPs form 6 families (OATP1-OATP6) and 13 subfamilies. In this review we try to summarize what is currently known about OATPs with respect to endogenous substrates, tissue distribution, transport mechanisms, regulation of expression, structure-function relationship and mutations and polymorphisms.
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Affiliation(s)
- Bruno Hagenbuch
- Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, KS 66160, USA.
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21
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Yu Y, Liu X, Zhang Z, Xiao Y, Hong M. Cloning and functional characterization of the pig (Sus scrofa) organic anion transporting polypeptide 1a2. Xenobiotica 2013; 43:738-44. [DOI: 10.3109/00498254.2012.760762] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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22
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Gong IY, Kim RB. Impact of Genetic Variation in OATP Transporters to Drug Disposition and Response. Drug Metab Pharmacokinet 2013; 28:4-18. [DOI: 10.2133/dmpk.dmpk-12-rv-099] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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23
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Liu X, Huang J, Sun Y, Zhan K, Zhang Z, Hong M. Identification of multiple binding sites for substrate transport in bovine organic anion transporting polypeptide 1a2. Drug Metab Dispos 2012; 41:602-7. [PMID: 23255551 DOI: 10.1124/dmd.112.047910] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Organic anion transporting polypeptides (OATP) have been extensively recognized as key determinants of absorption, distribution, metabolism, and excretion of various drugs because of their broad substrate specificity, wide tissue distribution, and the involvement of drug-drug interaction. As the first cloned human OATP, OATP1A2 has been found to transport a wide spectrum of endogenous and exogenous compounds. Bovine Oapt1a2 shared high homology with the human transporter and is considered as its functional ortholog. In the present study, we expressed bovine Oatp1a2 in human embryonic kidney 293 cells and found that, unlike human OATP1A2, the transport of estrone-3-sulfate (E-3-S) exhibited biphasic saturation kinetics. The K(m) values are 0.25 ± 0.08 and 46.6 ± 18.5 µM, and V(max) values were 24.5 ±4.4 and 375 ± 142 pmol/mg protein/min for high- and low-affinity sites, respectively, suggesting the presence of multiple binding sites. Further study on other Oatp1a2 substrates showed that the high affinity component for E-3-S is responsible for the interaction with taurocholate, bromsulphthalein, and rifampicin and is sensitive to proton concentration change, whereas the low affinity binding site is only involved in the binding of the antitumor drug methotrexate and had no response to change of pH.
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Affiliation(s)
- Xiaoxiao Liu
- College of Life Science and Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms, South China Agricultural University, Guangzhou, China
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24
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Olinga P, Meijer DK, Slooff MJ, Groothuis GM. Liver slices in in vitro pharmacotoxicology with special reference to the use of human liver tissue. Toxicol In Vitro 2012; 12:77-100. [PMID: 20654390 DOI: 10.1016/s0887-2333(97)00097-0] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/25/1997] [Indexed: 11/18/2022]
Abstract
In the early years of research in in vitro pharmacotoxicology liver slices have been used. After a decline in the application of slices in favour of the use of isolated hepatocytes and the isolated perfused liver preparation, the development of the Krumdieck slicer in the 1980s led to a ;comeback' of the technique. This review will focus on the use of human liver, with special reference to the comparison of slices with isolated hepatocytes in in vitro pharmacotoxicology. In addition, an overview on the predictive value of these in vitro systems for drug disposition and toxicity in vivo will be given. Preservation techniques for liver slices and hepatocytes will also be discussed. These techniques ensure an efficient utilization of the scarce human material. For long-term storage of liver slices and hepatocytes, cryopreservation seems most promising. However, cryopreservation is still in its infancy, and reports mainly deal with drug metabolism studies after cryopreservation. Drug toxicity, metabolism and transport data determined in slices and isolated hepatocytes, from both human and animal liver showed good correlation with the corresponding parameters measured in vivo. Therefore, the results obtained in such studies may give rise to more in-depth research on the mechanisms of pharmactoxicology in the human liver.
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Affiliation(s)
- P Olinga
- Division of Hepatobiliary Surgery and Liver Transplantation, Department of Surgery, University Hospital, Hanzeplein 1, 9713 EZ Groningen, The Netherlands
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25
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Roth M, Obaidat A, Hagenbuch B. OATPs, OATs and OCTs: the organic anion and cation transporters of the SLCO and SLC22A gene superfamilies. Br J Pharmacol 2012; 165:1260-87. [PMID: 22013971 DOI: 10.1111/j.1476-5381.2011.01724.x] [Citation(s) in RCA: 550] [Impact Index Per Article: 45.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The human organic anion and cation transporters are classified within two SLC superfamilies. Superfamily SLCO (formerly SLC21A) consists of organic anion transporting polypeptides (OATPs), while the organic anion transporters (OATs) and the organic cation transporters (OCTs) are classified in the SLC22A superfamily. Individual members of each superfamily are expressed in essentially every epithelium throughout the body, where they play a significant role in drug absorption, distribution and elimination. Substrates of OATPs are mainly large hydrophobic organic anions, while OATs transport smaller and more hydrophilic organic anions and OCTs transport organic cations. In addition to endogenous substrates, such as steroids, hormones and neurotransmitters, numerous drugs and other xenobiotics are transported by these proteins, including statins, antivirals, antibiotics and anticancer drugs. Expression of OATPs, OATs and OCTs can be regulated at the protein or transcriptional level and appears to vary within each family by both protein and tissue type. All three superfamilies consist of 12 transmembrane domain proteins that have intracellular termini. Although no crystal structures have yet been determined, combinations of homology modelling and mutation experiments have been used to explore the mechanism of substrate recognition and transport. Several polymorphisms identified in members of these superfamilies have been shown to affect pharmacokinetics of their drug substrates, confirming the importance of these drug transporters for efficient pharmacological therapy. This review, unlike other reviews that focus on a single transporter family, briefly summarizes the current knowledge of all the functionally characterized human organic anion and cation drug uptake transporters of the SLCO and the SLC22A superfamilies.
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Affiliation(s)
- Megan Roth
- Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, KS 66160, USA
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26
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Li N, Hong W, Huang H, Lu H, Lin G, Hong M. Identification of amino acids essential for estrone-3-sulfate transport within transmembrane domain 2 of organic anion transporting polypeptide 1B1. PLoS One 2012; 7:e36647. [PMID: 22574206 PMCID: PMC3344916 DOI: 10.1371/journal.pone.0036647] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 04/11/2012] [Indexed: 11/19/2022] Open
Abstract
As an important structure in membrane proteins, transmembrane domains have been found to be crucial for properly targeting the protein to cell membrane as well as carrying out transport functions in transporters. Computer analysis of OATP sequences revealed transmembrane domain 2 (TM2) is among those transmembrane domains that have high amino acid identities within different family members. In the present study, we identify four amino acids (Asp70, Phe73, Glu74, and Gly76) that are essential for the transport function of OATP1B1, an OATP member that is specifically expressed in the human liver. A substitution of these four amino acids with alanine resulted in significantly reduced transport activity. Further mutagenesis showed the charged property of Asp70 and Glu74 is critical for proper function of the transporter protein. Comparison of the kinetic parameters indicated that Asp70 is likely to interact with the substrate while Glu74 may be involved in stabilizing the binding site through formation of a salt-bridge. The aromatic ring structure of Phe73 seems to play an important role because substitution of Phe73 with tyrosine, another amino acid with a similar structure, led to partially restored transport function. On the other hand, replacement of Gly76 with either alanine or valine could not recover the function of the transporter. Considering the nature of a transmembrane helix, we proposed that Gly76 may be important for maintaining the proper structure of the protein. Interestingly, when subjected to transport function analysis of higher concentration of esteone-3-sulfate (50 µM) that corresponds to the low affinity binding site of OATP1B1, mutants of Phe73, Glu74, and Gly76 all showed a transport function that is comparable to that of the wild-type, suggesting these amino acids may have less impact on the low affinity component of esteone-3-sulfate within OATP1B1, while Asp 70 seems to be involved in the interaction of both sites.
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Affiliation(s)
- Nan Li
- College of Life Science, South China Agricultural University, Guangzhou, China
| | - Weifang Hong
- College of Life Science, South China Agricultural University, Guangzhou, China
| | - Hong Huang
- School of Information, University of South Florida, Tampa, Florida, United States of America
| | - Hanping Lu
- Zhongshan School of Medicine, Zhongshan (Sun Yat-sen) University, Guangzhou, China
| | - Guangyun Lin
- Zhongshan School of Medicine, Zhongshan (Sun Yat-sen) University, Guangzhou, China
| | - Mei Hong
- College of Life Science, South China Agricultural University, Guangzhou, China
- * E-mail:
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27
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Grandvuinet AS, Vestergaard HT, Rapin N, Steffansen B. Intestinal transporters for endogenic and pharmaceutical organic anions: the challenges of deriving in-vitro kinetic parameters for the prediction of clinically relevant drug-drug interactions. ACTA ACUST UNITED AC 2012; 64:1523-48. [PMID: 23058041 DOI: 10.1111/j.2042-7158.2012.01505.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVES This review provides an overview of intestinal human transporters for organic anions and stresses the need for standardization of the various in-vitro methods presently employed in drug-drug interaction (DDI) investigations. KEY FINDINGS Current knowledge on the intestinal expression of the apical sodium-dependent bile acid transporter (ASBT), the breast cancer resistance protein (BCRP), the monocarboxylate transporters (MCT) 1, MCT3-5, the multidrug resistance associated proteins (MRP) 1-6, the organic anion transporting polypetides (OATP) 2B1, 1A2, 3A1 and 4A1, and the organic solute transporter α/β (OSTα/β) has been covered along with an overview of their substrates and inhibitors. Furthermore, the many challenges in predicting clinically relevant DDIs from in-vitro studies have been discussed with focus on intestinal transporters and the various methods for deducting in-vitro parameters for transporters (K(m) /K(i) /IC50, efflux ratio). The applicability of using a cut-off value (estimated based on the intestinal drug concentration divided by the K(i) or IC50) has also been considered. SUMMARY A re-evaluation of the current approaches for the prediction of DDIs is necessary when considering the involvement of other transporters than P-glycoprotein. Moreover, the interplay between various processes that a drug is subject to in-vivo such as translocation by several transporters and dissolution should be considered.
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Affiliation(s)
- Anne Sophie Grandvuinet
- Drug Transporters in ADME, Department of Pharmaceutics and Analytical Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen, Copenhagen, Denmark
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Diaz GJ. Basolateral and canalicular transport of xenobiotics in the hepatocyte: A review. Cytotechnology 2011; 34:225-35. [PMID: 19003398 DOI: 10.1023/a:1008152205697] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The molecular and functional characterization of severalproteins involved in the uptake and excretion of xenobioticsand endogenous compounds in the hepatocyte has been achievedthrough intensive research conducted in the past few years.These studies have lead to the identification of specificmembrane transporters located in the basolateral andcanalicular membrane domains of the hepatocyte. The organicanion-transporting polypeptide (OATP), present in thebasolateral membrane of the hepatocyte, is responsible for thetranslocation of xenobiotics from the sinusoidal space into thehepatocyte. Once inside the cell, unconjugated neutral, anionicand cationic xenobiotics can be secreted into bile by themultidrug-resistance P-glycoprotein 1 (MDR1). Conjugatedxenobiotics (e.g. glucuronides and glutathione conjugates) aresecreted into bile by the canalicular multispecific organicanion transporter (cMOAT). Other transporters play keyphysiological roles, including the basolateral uptake of bilesalts (sodium-taurocholate cotransporter, NTCP) and thesecretion into bile of conjugated and unconjugated bile salts(bile salt export pump, BSEP) and phospholipids (MDR2).Experimental approaches used to investigate the role of thebasolateral and canalicular transporters in the hepatocyte haveincluded both in vivo and in vitro models. Animalmodels lacking canalicular transporters include the;hyperbilirubinemic' rats (Groningen-Yellow (GY), Eisaihyperbilirubinemic (EHB) and TR(-) rats), which aredeficient in the cMOAT protein, and ;knock-out' mice, lackingeither the MDR1 or MDR2 transporter. Although no animal modelsare currently available for the study of basolateraltransporters, their function has been conveniently investigatedthrough heterologous expression in Xenopus laevis oocytesand also with basolateral membrane vesicles isolated fromhepatocytes. The total number of basolateral and canaliculartransport proteins present in the hepatocyte is still unknown,but current knowledge indicates that there are at least fourpresent in the basolateral membrane and five in the canaliculardomain. The present review focuses on the current knowledgeabout the most relevant hepatocyte transporters involved in theuptake of foreign and endogenous compounds from the sinusoidalspace and in their active secretion into bile. The first partof the review deals with the basolateral (sinusoidal) transportof organic anions, and the major basolateral transporters (e.g.NTCP, OATP) are described here, both in terms of their knownbiochemistry and physiology. In the second part of the review,the canalicular (apical) transport of organic anions isdiscussed and the biochemistry and physiological role of MDR1,MDR2, cMOAT and BSEP is described in detail. The concludingremarks point out areas of research that need to be addressedin order to answer important questions that still remainunanswered in this important field of study.
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Affiliation(s)
- G J Diaz
- Facultad de Medicina Veterinaria y de Zootecnia, Universidad Nacional de Colombia, Apartado Aéreo 76948, Santafé de Bogotá, D.C., Colombia;,
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Determination of OATP-, NTCP- and OCT-mediated substrate uptake activities in individual and pooled batches of cryopreserved human hepatocytes. Eur J Pharm Sci 2011; 43:297-307. [DOI: 10.1016/j.ejps.2011.05.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Revised: 04/01/2011] [Accepted: 05/07/2011] [Indexed: 01/11/2023]
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Kramer W. Transporters, Trojan horses and therapeutics: suitability of bile acid and peptide transporters for drug delivery. Biol Chem 2011; 392:77-94. [PMID: 21194371 DOI: 10.1515/bc.2011.017] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Membrane transporters are major determinants for the pharmacokinetic, safety and efficacy behavior of drugs. Available technologies to study function and structure of transport proteins has strongly stimulated research in transporter biology and uncovered their importance for the drug discovery and development process, especially for drug absorption and disposition. Physiological transport systems are investigated as potential ferries to improve drug absorption and membrane permeation and to achieve organ-specific drug action. In particular, the bile acid transport systems in the liver and the small intestine and the oligopeptide transporters are of significant importance for molecular drug delivery.
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Affiliation(s)
- Werner Kramer
- Sanofi-Aventis Deutschland GmbH, Industriepark Höchst, Gebäude G 879, Frankfurt/Main, Germany.
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König J. Uptake transporters of the human OATP family: molecular characteristics, substrates, their role in drug-drug interactions, and functional consequences of polymorphisms. Handb Exp Pharmacol 2011:1-28. [PMID: 21103967 DOI: 10.1007/978-3-642-14541-4_1] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Organic anion transporting polypeptides (OATPs, gene family: SLC21/SLCO) mediate the uptake of a broad range of substrates including several widely prescribed drugs into cells. Drug substrates for members of the human OATP family include HMG-CoA-reductase inhibitors (statins), antibiotics, anticancer agents, and cardiac glycosides. OATPs are expressed in a variety of different tissues including brain, intestine, liver, and kidney, suggesting that these uptake transporters are important for drug absorption, distribution, and excretion. Because of their wide tissue distribution and broad substrate spectrum, altered transport kinetics, for example, due to drug-drug interactions or due to the functional consequences of genetic variations (polymorphisms), can contribute to the interindividual variability of drug effects. Therefore, the molecular characteristics of human OATP family members, the role of human OATPs in drug-drug interactions, and the in vitro analysis of the functional consequences of genetic variations in SLCO genes encoding OATP proteins are the focus of this chapter.
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Affiliation(s)
- Jörg König
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany.
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Yamaguchi H, Sugie M, Okada M, Mikkaichi T, Toyohara T, Abe T, Goto J, Hishinuma T, Shimada M, Mano N. Transport of estrone 3-sulfate mediated by organic anion transporter OATP4C1: estrone 3-sulfate binds to the different recognition site for digoxin in OATP4C1. Drug Metab Pharmacokinet 2010; 25:314-7. [PMID: 20610891 DOI: 10.2133/dmpk.25.314] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Human organic anion transporter OATP4C1 is a member of the OATP family predominantly expressed in the kidney, and contributes to the renal secretion of digoxin. However, little is known about the characteristics of OATP4C1-madiated transport. We examined the transport of estrone 3-sulfate, which is known as a substrate for other OATPs, by OATP4C1-expressing cells. Estrone 3-sulfate was efficiently transported by OATP4C1. The Michaelis-Menten constant for estrone 3-sulfate uptake by OATP4C1 was 26.6+/-4.9 microM. Transport of estrone 3-sulfate was significantly inhibited by triiodothyronine, chenodeoxycholic acid, bromosulfophtalein, and cyclosporine, whereas known substrates of OATP4C1, digoxin and ouabain, did not change OATP4C1-mediated transport. We further examined the mutual inhibition study between estrone 3-sulfate and digoxin. Digoxin partially inhibited the estrone 3-sulfate transport, and estrone 3-sulfate did not significantly inhibit digoxin transport. The estimated IC(50) value of digoxin for OATP4C1-mediated estrone 3-sulfate transport was 119 microM. This value is not comparable with the Michaelis-Menten constant for digoxin uptake by OATP4C1 (7.8 microM) reported by Mikkaichi et al.(1)) In conclusion, we found that estrone 3-sulfate is a novel substrate for OATP4C1. Moreover, our results indicate that estrone 3-sulfate does not bind to the recognition site for digoxin in OATP4C1.
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Affiliation(s)
- Hiroaki Yamaguchi
- Department of Pharmaceutical Sciences, Tohoku University Hospital, 1-1 Seiryo-machi, Aoba-ku, Sendai, Japan
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Han YH, Busler D, Hong Y, Tian Y, Chen C, Rodrigues AD. Transporter Studies with the 3-O-Sulfate Conjugate of 17α-Ethinylestradiol: Assessment of Human Liver Drug Transporters. Drug Metab Dispos 2010; 38:1072-82. [DOI: 10.1124/dmd.109.031518] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
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Abstract
Membrane transporters are now recognized as important determinants of the transmembrane passage of drugs. Organic anion transporting polypeptides (OATP) form a family of influx transporters expressed in various tissues important for pharmacokinetics. Of the 11 human OATP transporters, OATP1B1, OATP1B3 and OATP2B1 are expressed on the sinusoidal membrane of hepatocytes and can facilitate the liver uptake of their substrate drugs. OATP1A2 is expressed on the luminal membrane of small intestinal enterocytes and at the blood-brain barrier, potentially mediating drug transport at these sites. Several clinically used drugs have been identified as substrates of OATP transporters (e.g. many statins are substrates of OATP1B1). Some drugs may inhibit OATP transporters (e.g. cyclosporine) causing pharmacokinetic drug-drug interactions. Moreover, genetic variability in genes encoding OATP transporters can result in marked inter-individual differences in pharmacokinetics. For example, a single nucleotide polymorphism (c.521T > C, p.Val174Ala) in the SLCO1B1 gene encoding OATP1B1 decreases the ability of OATP1B1 to transport active simvastatin acid from portal circulation into the liver, resulting in markedly increased plasma concentrations of simvastatin acid and an enhanced risk of simvastatin-induced myopathy. SLCO1B1 polymorphism also affects the pharmacokinetics of many other, but not all (fluvastatin), statins and that of the antidiabetic drug repaglinide, the antihistamine fexofenadine and the endothelin A receptor antagonist atrasentan. This review compiles the current knowledge about the expression and function of human OATP transporters, their substrate and inhibitor specificities, as well as pharmacogenetics.
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Affiliation(s)
- A Kalliokoski
- Department of Clinical Pharmacology, University of Helsinki, Helsinki, Finland
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Urquhart BL, Kim RB. Blood−brain barrier transporters and response to CNS-active drugs. Eur J Clin Pharmacol 2009; 65:1063-70. [DOI: 10.1007/s00228-009-0714-8] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2009] [Accepted: 07/28/2009] [Indexed: 10/20/2022]
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Herraez E, Macias RI, Vazquez-Tato J, Vicens M, Monte MJ, Marin JJ. In vitro inhibition of OATP-mediated uptake of phalloidin using bile acid derivatives. Toxicol Appl Pharmacol 2009; 239:13-20. [DOI: 10.1016/j.taap.2009.04.024] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2009] [Revised: 04/13/2009] [Accepted: 04/14/2009] [Indexed: 11/25/2022]
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Franke RM, Scherkenbach LA, Sparreboom A. Pharmacogenetics of the organic anion transporting polypeptide 1A2. Pharmacogenomics 2009; 10:339-44. [PMID: 19290786 DOI: 10.2217/14622416.10.3.339] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The solute carrier, human organic anion transporting polypeptide 1A2 (OATP1A2, OATP-A, OATP1 and OATP) is highly expressed in the intestine, kidney, cholangiocytes and the blood-brain barrier. This localization suggests that OATP1A2 may be vitally important in the absorption, distribution and excretion of a broad array of clinically important drugs. Several nonsynonymous polymorphisms have been identified in the gene encoding OATP1A2, SLCO1A2 (SLC21A3), with some of these variants demonstrating functional changes in the transport of OATP1A2 substrates.
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Affiliation(s)
- Ryan M Franke
- Department of Pharmaceutical Sciences, St Jude Children's Hospital, 332 North Lauderdale, DTRC, Mail Stop 313, Room I5308, Memphis, TN 38105, USA
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Hagenbuch B, Gui C. Xenobiotic transporters of the human organic anion transporting polypeptides (OATP) family. Xenobiotica 2008; 38:778-801. [PMID: 18668430 DOI: 10.1080/00498250801986951] [Citation(s) in RCA: 299] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
1. The organic anion transporting polypeptides (humans OATP; other species Oatp) belong to the SLCO gene superfamily of transporters and are twelve transmembrane domain glycoproteins expressed in various epithelial cells. Some OATPs/Oatps are expressed in a single organ, while others are expressed ubiquitously. 2. The functionally characterized members mediate sodium-independent transport of a variety of structurally independent, mainly amphipathic organic compounds, including bile salts, hormones and their conjugates, toxins, and various drugs. 3. This review summarizes the general features and the substrates of the eleven human OATPs. Furthermore, it reviews what is known about the mechanism of their multispecificity, their predicted structure, their role in drug-food interactions, and their role in cancer. 4. Finally, some open questions are raised that need to be addressed to advance OATP research in the near future.
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Affiliation(s)
- B Hagenbuch
- The University of Kansas Medical Center, Pharmacology, Toxicology and Therapeutics, Kansas City, KS 66160, USA.
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40
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Campion SN, Johnson R, Aleksunes LM, Goedken MJ, van Rooijen N, Scheffer GL, Cherrington NJ, Manautou JE. Hepatic Mrp4 induction following acetaminophen exposure is dependent on Kupffer cell function. Am J Physiol Gastrointest Liver Physiol 2008; 295:G294-304. [PMID: 18556419 PMCID: PMC2519859 DOI: 10.1152/ajpgi.00541.2007] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
During acetaminophen (APAP) hepatotoxicity, increased expression of multidrug resistance-associated proteins 2, 3, and 4 (Mrp2-4) occurs. Mrp4 is the most significantly upregulated transporter in mouse liver following APAP treatment. Although the expression profiles of liver transporters following APAP hepatotoxicity are well characterized, the regulatory mechanisms contributing to these changes remain unknown. We hypothesized that Kupffer cell-derived mediators participate in the regulation of hepatic transporters during APAP toxicity. To investigate this, C57BL/6J mice were pretreated with clodronate liposomes (0.1 ml iv) to deplete Kupffer cells and then challenged with APAP (500 mg/kg ip). Liver injury was assessed by plasma alanine aminotransferase and hepatic transporter protein expression was determined by Western blot and immunohistochemistry. Depletion of Kupffer cells by liposomal clodronate increased susceptibility to APAP hepatotoxicity. Although increased expression of several efflux transporters was observed after APAP exposure, only Mrp4 was found to be differentially regulated following Kupffer cell depletion. At 48 and 72 h after APAP dosing, Mrp4 levels were increased by 10- and 33-fold, respectively, in mice receiving empty liposomes. Immunohistochemistry revealed Mrp4 staining confined to centrilobular hepatocytes. Remarkably, Kupffer cell depletion completely prevented Mrp4 induction by APAP. Elevated plasma levels of TNF-alpha and IL-1beta were also prevented by Kupffer cell depletion. These findings show that Kupffer cells protect the liver from APAP toxicity and that Kupffer cell mediators released in response to APAP are likely responsible for the induction of Mrp4.
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Affiliation(s)
- Sarah N. Campion
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut; Department of Pathology, Schering Plough Research Institute, Lafayette, New Jersey; Departments of Molecular Cell Biology and Pathology, Vrije Universiteit Medical Center, Amsterdam, The Netherlands; and Department of Pharmacology and Toxicology, University of Arizona, Tucson, Arizona
| | - Rachel Johnson
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut; Department of Pathology, Schering Plough Research Institute, Lafayette, New Jersey; Departments of Molecular Cell Biology and Pathology, Vrije Universiteit Medical Center, Amsterdam, The Netherlands; and Department of Pharmacology and Toxicology, University of Arizona, Tucson, Arizona
| | - Lauren M. Aleksunes
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut; Department of Pathology, Schering Plough Research Institute, Lafayette, New Jersey; Departments of Molecular Cell Biology and Pathology, Vrije Universiteit Medical Center, Amsterdam, The Netherlands; and Department of Pharmacology and Toxicology, University of Arizona, Tucson, Arizona
| | - Michael J. Goedken
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut; Department of Pathology, Schering Plough Research Institute, Lafayette, New Jersey; Departments of Molecular Cell Biology and Pathology, Vrije Universiteit Medical Center, Amsterdam, The Netherlands; and Department of Pharmacology and Toxicology, University of Arizona, Tucson, Arizona
| | - Nico van Rooijen
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut; Department of Pathology, Schering Plough Research Institute, Lafayette, New Jersey; Departments of Molecular Cell Biology and Pathology, Vrije Universiteit Medical Center, Amsterdam, The Netherlands; and Department of Pharmacology and Toxicology, University of Arizona, Tucson, Arizona
| | - George L. Scheffer
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut; Department of Pathology, Schering Plough Research Institute, Lafayette, New Jersey; Departments of Molecular Cell Biology and Pathology, Vrije Universiteit Medical Center, Amsterdam, The Netherlands; and Department of Pharmacology and Toxicology, University of Arizona, Tucson, Arizona
| | - Nathan J. Cherrington
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut; Department of Pathology, Schering Plough Research Institute, Lafayette, New Jersey; Departments of Molecular Cell Biology and Pathology, Vrije Universiteit Medical Center, Amsterdam, The Netherlands; and Department of Pharmacology and Toxicology, University of Arizona, Tucson, Arizona
| | - José E. Manautou
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut; Department of Pathology, Schering Plough Research Institute, Lafayette, New Jersey; Departments of Molecular Cell Biology and Pathology, Vrije Universiteit Medical Center, Amsterdam, The Netherlands; and Department of Pharmacology and Toxicology, University of Arizona, Tucson, Arizona
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Seithel A, Glaeser H, Fromm MF, König J. The functional consequences of genetic variations in transporter genes encoding human organic anion-transporting polypeptide family members. Expert Opin Drug Metab Toxicol 2008; 4:51-64. [PMID: 18370858 DOI: 10.1517/17425255.4.1.51] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
It is increasingly recognised that uptake transporters of the organic anion-transporting polypeptide (OATP) family play important roles in drug absorption, distribution and excretion. They are expressed in a variety of different tissues, including gut, brain, kidney and liver. Substrates of OATPs include several endogenous substances, such as bile salts and hormones, and drugs such as HMG-CoA reductase inhibitors (e.g., pravastatin), cytotoxic drugs and antibiotics. Recent advances in the pharmacogenetics of OATPs have demonstrated that variations (polymorphisms) in genes encoding human OATPs can explain parts of the interindividual variability in the pharmacokinetics of drugs and, thus, contribute to the interethnic and interindividual variability in drug response. This review focuses on consequences of these genetic variations and summarises in vivo as well as in vitro analyses demonstrating the impact of polymorphisms in genes encoding OATPs on transport and pharmacokinetics of drugs.
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Affiliation(s)
- Annick Seithel
- Friedrich-Alexander-University Erlangen-Nuremberg, Institute of Experimental and Clinical Pharmacology and Toxicology, Fahrstrasse 17, 91054 Erlangen, Germany
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Urquhart BL, Tirona RG, Kim RB. Nuclear receptors and the regulation of drug-metabolizing enzymes and drug transporters: implications for interindividual variability in response to drugs. J Clin Pharmacol 2007; 47:566-78. [PMID: 17442683 DOI: 10.1177/0091270007299930] [Citation(s) in RCA: 262] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Erratic or unpredictable response to drugs remains a challenge of modern drug therapy. An important determinant of such interindividual differences in drug response is variability in the expression of drug-metabolizing enzymes and/or transporters at sites of absorption and/or tissue distribution. Variable drug-metabolizing enzyme and transporter expression can result in unpredictable exposure and tissue distribution of drugs and may manifest as adverse effects or therapeutic failure. In the past decade, important new insights have been made relating to the regulatory mechanisms governing the expression of drug-metabolizing enzymes and transporters by ligand-activated nuclear receptors. Specifically, there is compelling evidence to demonstrate that PXR, CAR, FXR, LXR, VDR, HNF4alpha, and AhR form a battery of nuclear receptors that regulate the expression of many important drug-metabolizing enzyme and transporters. In this review, the authors focus on clinically important drug-metabolizing enzymes such as CYP3A4, CYP2B6, CYP2C9, CYP2C19, UGT1A1, SULT2A1, and glutathione S-transferases and their regulation by nuclear receptors. They also review the nuclear receptor-mediated regulation of drug transporters such as MDR1, MRP2, MRP4, BSEP, BCRP, NTCP, OATP1B3, and OATP1A2. Finally, they outline how the drug development process has been affected by the current understanding of the involvement of nuclear receptors in the regulation of drug disposition genes.
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Affiliation(s)
- Bradley L Urquhart
- Division of Clinical Pharmacology, London Health Sciences Centre-University Hospital, Room ALL-152, 339 Windermere Road, London, Ontario N6A 5A5, Canada
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Lau YY, Huang Y, Frassetto L, Benet LZ. effect of OATP1B transporter inhibition on the pharmacokinetics of atorvastatin in healthy volunteers. Clin Pharmacol Ther 2006; 81:194-204. [PMID: 17192770 DOI: 10.1038/sj.clpt.6100038] [Citation(s) in RCA: 271] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The inhibition of hepatic uptake transporters, such as OATP1B1, on the pharmacokinetics of atorvastatin is unknown. Here, we investigate the effect of a model hepatic transporter inhibitor, rifampin, on the kinetics of atorvastatin and its metabolites in humans. The inhibitory effect of a single rifampin dose on atorvastatin kinetics was studied in 11 healthy volunteers in a randomized, crossover study. Each subject received two 40-mg doses of atorvastatin, one on study day 1 and one on study day 8, separated by 1 week. One intravenous 30-min infusion of 600 mg rifampin was administered to each subject on either study day 1 or study day 8. Plasma concentrations of atorvastatin and metabolites were above the limits of quantitation for up to 24 h after dosing. Rifampin significantly increased the total area under the plasma concentration-time curve (AUC) of atorvastatin acid by 6.8+/-2.4-fold and that of 2-hydroxy-atorvastatin acid and 4-hydroxy-atorvastatin acid by 6.8+/-2.5- and 3.9+/-2.4-fold, respectively. The AUC values of the lactone forms of atorvastatin, 2-hydroxy-atorvastatin and 4-hydroxy-atorvastatin, were also significantly increased, but to a lower extent. An intravenous dose of rifampin substantially increased the plasma concentrations of atorvastatin and its acid and lactone metabolites. The data confirm that OATP1B transporters represent the major hepatic uptake systems for atorvastatin and its active metabolites. Inhibition of hepatic uptake may have consequences for efficacy and toxicity of drugs like atorvastatin that are mainly eliminated by the hepatobiliary system.
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Affiliation(s)
- Y Y Lau
- Department of Biopharmaceutical Sciences, University of California, San Francisco, California, USA
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44
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König J, Seithel A, Gradhand U, Fromm MF. Pharmacogenomics of human OATP transporters. Naunyn Schmiedebergs Arch Pharmacol 2006; 372:432-43. [PMID: 16525793 DOI: 10.1007/s00210-006-0040-y] [Citation(s) in RCA: 253] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2005] [Accepted: 01/23/2006] [Indexed: 01/27/2023]
Abstract
Organic anion transporting polypeptides (OATPs) mediate the uptake of a broad range of compounds into cells. Substrates for members of the OATP family include bile salts, hormones, and steroid conjugates as well as drugs like the HMG-CoA-reductase inhibitors (statins), cardiac glycosides, anticancer agents like methotrexate, and antibiotics like rifampicin. OATPs are expressed in a variety of different tissues, including intestine, liver, kidney, and brain, suggesting that they play a critical role in drug absorption, distribution, and excretion. The identification and functional characterisation of naturally occurring variations in genes encoding human OATP (SLCO) family members is in the focus of transporter research. As a result of their broad substrate spectrum and their wide tissue distribution, altered transport characteristics or protein localisation can contribute significantly to interindividual variations of drug effects. The analysis of the consequences of genetic variations in genes encoding transport proteins may, therefore, contribute to a better understanding of interindividual differences in drug effects and to individualise treatment regimens with drugs that are substrates for human OATP proteins. In this review, we summarise the current knowledge on genetic variations in transporter genes encoding human OATP family members and their functional consequences analysed by in vitro and in vivo studies.
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Affiliation(s)
- Jörg König
- Institute for Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-University Erlangen-Nuremberg, Fahrstr. 17, 91054, Erlangen, Germany.
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45
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Miki Y, Suzuki T, Kitada K, Yabuki N, Shibuya R, Moriya T, Ishida T, Ohuchi N, Blumberg B, Sasano H. Expression of the steroid and xenobiotic receptor and its possible target gene, organic anion transporting polypeptide-A, in human breast carcinoma. Cancer Res 2006; 66:535-42. [PMID: 16397270 DOI: 10.1158/0008-5472.can-05-1070] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Steroid and xenobiotic receptor (SXR) or human pregnane X receptor (hPXR) has been shown to play an important role in the regulation of genes related to xenobiotic detoxification, such as cytochrome P450 3A4 and multidrug resistance gene 1. Cytochrome P450 enzymes, conjugation enzymes, and transporters are all considered to be involved in the resistance of breast carcinoma to chemotherapeutic or endocrine agents. However, the expression of SXR/hPXR proteins and that of its target genes and their biological or clinical significance have not been examined in human breast carcinomas. Therefore, we first examined SXR/hPXR expression in 60 breast carcinomas using immunohistochemistry and quantitative reverse transcription-PCR. We then searched for possible SXR/hPXR target genes using microarray analysis of carcinoma cells captured by laser microscissors. SXR/hPXR was detected in carcinoma tissues but not in nonneoplastic and stromal cells of breast tumors. A significant positive correlation was detected between the SXR/hPXR labeling index and both the histologic grade and the lymph node status of the carcinoma cases. Furthermore, in estrogen receptor-positive cases, SXR/hPXR expression was also positively correlated with expression of the cell proliferation marker, Ki-67. Microarray analysis showed that organic anion transporting polypeptide-A (OATP-A) was most closely correlated with SXR/hPXR gene expression, and both OATP-A mRNA and protein were significantly associated with SXR/hPXR in both breast carcinoma tissues and its cell lines. These results suggest that SXR/hPXR and its target gene, such as OATP-A, may play important roles in the biology of human breast cancers.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1/biosynthesis
- ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics
- Adult
- Aged
- Breast Neoplasms/genetics
- Breast Neoplasms/metabolism
- Breast Neoplasms/pathology
- Carcinoma, Ductal/genetics
- Carcinoma, Ductal/metabolism
- Carcinoma, Ductal/pathology
- Cell Line, Tumor
- Cluster Analysis
- Cytochrome P-450 CYP3A
- Cytochrome P-450 Enzyme System/biosynthesis
- Cytochrome P-450 Enzyme System/genetics
- Female
- Humans
- Immunohistochemistry
- Middle Aged
- Oligonucleotide Array Sequence Analysis
- Organic Anion Transporters/biosynthesis
- Organic Anion Transporters/genetics
- Pregnane X Receptor
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Receptors, Steroid/biosynthesis
- Receptors, Steroid/genetics
- Reverse Transcriptase Polymerase Chain Reaction
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Affiliation(s)
- Yasuhiro Miki
- Department of Pathology, Tohoku University Graduate School of Medicine, Sendai, Miyagi-ken, Japan
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Lu WJ, Tamai I, Nezu JI, Lai ML, Huang JD. Organic anion transporting polypeptide-C mediates arsenic uptake in HEK-293 cells. J Biomed Sci 2006; 13:525-33. [PMID: 16479312 DOI: 10.1007/s11373-006-9071-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2005] [Accepted: 01/09/2006] [Indexed: 11/27/2022] Open
Abstract
Arsenic is an established human carcinogen. The role of aquaglyroporins (AQPs) in arsenic disposition was recently identified. In order to examine whether organic anion transporting polypeptide-C (OATP-C) also plays a role in arsenic transport, OATP-C cDNA was transfected into cells of a human embryonic kidney cell line (HEK-293). Transfection increased uptake of the model OATP-C substrate, estradiol-17beta-D-glucuronide, by 10-fold. In addition, we measured uptake and cytotoxicity of arsenate, arsenite, monomethylarsonate(MMA(V)), and dimethylarsinate (DMA(V)). Transfection of OATP-C increased uptake and cytotoxicity of arsenate and arsenite, but not of MMA(V) or DMA(V). Rifampin and taurocholic acid (a substrate of OATP-C) reversed the increased toxicity of arsenate and arsenite seen in OATP-C-transfected cells. The increase in uptake of inorganic arsenic was not as great as that of estradiol-17beta-D-glucuronide. Our results suggest that OATP-C can transport inorganic arsenic in a (GSH)-dependent manner. However, this may not be the major pathway for arsenic transport.
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Affiliation(s)
- Wen-Jen Lu
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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47
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Kusuhara H, Sugiyama Y. Active efflux across the blood-brain barrier: role of the solute carrier family. NeuroRx 2005; 2:73-85. [PMID: 15717059 PMCID: PMC539323 DOI: 10.1602/neurorx.2.1.73] [Citation(s) in RCA: 182] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The brain uptake of xenobiotics is restricted by the blood-brain brain barrier formed by brain capillary endothelial cells. Active efflux transport systems in the blood-brain barrier work as a detoxification system in the brain by facilitating removal of xenobiotic compounds from the brain. Drugs, acting in the brain, have to overcome such efflux mechanisms to achieve clinically significant concentration in the brain. Multiple transporters are involved in this efflux transport in the brain capillaries. In the past few years, considerable progress has been made in the cloning of these transporters and their functional characterization after heterologous expression. Members of the solute carrier family (SLC) play an important role in the efflux transport, especially for organic anions, which include organic anion transporting polypeptides (OATP/SLCO) and organic anion transporters (OAT/SLC22A). It is believed that coordination of the members of SLC family, and ABC transporters, such as P-glycoprotein, multidrug resistance protein, and breast cancer-resistant protein (BCRP/ABCG2), allows an efficient vectorial transport across the endothelial cells to remove xenobiotics from the brain. In this review, we shall summarize our current knowledge about their localization, molecular and functional characteristics, and substrate and inhibitor specificity.
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Affiliation(s)
- Hiroyuki Kusuhara
- Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo 113-0033, Japan.
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Su Y, Zhang X, Sinko PJ. Human organic anion-transporting polypeptide OATP-A (SLC21A3) acts in concert with P-glycoprotein and multidrug resistance protein 2 in the vectorial transport of Saquinavir in Hep G2 cells. Mol Pharm 2005; 1:49-56. [PMID: 15832500 DOI: 10.1021/mp0340136] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Saquinavir mesylate (SQV) is the first-in-class and prototypical HIV protease inhibitor (PI) used in the treatment of HIV infection. SQV undergoes extensive hepatic metabolism and intestinal and bile secretion, and has poor and variable oral bioavailability. In previous studies, our group and others have described the interactions between SQV and absorptive and secretory efflux transporters such as MRP1, MRP2, and P-gp. However, the potential role of absorptive influx transporters such as OATP-A (SLC21A3) has not yet been reported for SQV. In the study presented here, the role of OATP-A in the influx transport of SQV was studied using a hepatic cell model, Hep G2, and Xenopus laevis oocytes overexpressing human OATP-A. In Hep G2 cells, SQV transport was found to be (i) concentration-dependent and saturable, (ii) temperature-sensitive, and (iii) proton (pH)- and sodium-independent. While GF120918, a specific inhibitor of P-gp, and MK571, a MRP transporter family inhibitor, significantly enhanced SQV uptake, estrone 3-sulfate, a substrate of OATP-A, significantly inhibited SQV uptake by Hep G2 cells. The observation that inhibitors of P-gp, MRP, or OATP-A have opposite effects on SQV uptake in polarized Hep G2 cells is consistent with their functions as hepatic efflux or influx transporters. In X. laevis oocytes into which OATP-A cRNA had been injected, the level of uptake of SQV was significantly greater than the level of uptake by oocytes into which water had been injected and was concentration-dependent and saturable (Km = 36.4+/-21.8 microM). This is the first report showing that SQV influx transport is directly facilitated by OATP-A. Given the wide body distribution of OATP-A, the current results suggest a potentially important role for OATP-A in the absorption and disposition of SQV in vivo. The data also suggest that in human hepatocytes basolaterally located OATP-A (influx transporter) may act in concert with apically located P-gp and/or MRP2 (efflux transporters) for the vectorial transport and excretion of SQV into bile.
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Affiliation(s)
- Yaming Su
- Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA
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49
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Abstract
Thyroid hormone is essential for the development of the brain and the nervous system. Cellular entry is required for conversion of thyroid hormones by the intracellular deiodinases and for binding of T(3) to its nuclear receptors. Several transporters capable of thyroid hormone transport have been identified. Functional expression studies using Xenopus laevis oocytes have so far identified two categories of transporters involved in thyroid hormone uptake (i.e., organic anion transporters and amino acid transporters). Among the organic anion transporters, both Na(+) taurocholate cotransporting polypeptide (NTCP) and various members of the organic anion transporting polypeptide (OATP) family mediate transport of iodothyronines. Because iodothyronines are a particular class of amino acids derived from tyrosine residues, it is no surprise that some amino acid transporters have been shown to be involved in thyroid hormone transport. We have characterized monocarboxylate transporter 8 (MCT8) as a very active and specific thyroid hormone transporter, the gene of which is located on the X chromosome. MCT8 is highly expressed in liver and brain but is also widely distributed in other tissues. MCT8 shows 50% amino acid identity with a system T amino acid transporter 1 (TAT1). TAT1, also called MCT10, has been characterized to transport aromatic amino acids but no iodothyronines. We have also found that mutations in MCT8 are associated with severe X-linked psychomotor retardation and strongly elevated serum T(3) levels in young boys.
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Affiliation(s)
- Edith C H Friesema
- Department of Internal Medicine, Erasmus MC, Dr Molewaterplein 50, 3015 GE Rotterdam, The Netherlands
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50
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Steffansen B, Nielsen CU, Brodin B, Eriksson AH, Andersen R, Frokjaer S. Intestinal solute carriers: an overview of trends and strategies for improving oral drug absorption. Eur J Pharm Sci 2004; 21:3-16. [PMID: 14706808 DOI: 10.1016/j.ejps.2003.10.010] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
A large amount of absorptive intestinal membrane transporters play an important part in absorption and distribution of several nutrients, drugs and prodrugs. The present paper gives a general overview on intestinal solute carriers as well as on trends and strategies for targeting drugs and/or prodrugs to these carriers in order to increasing oral bioavailability and distribution. A number of absorptive intestinal transporters are described in terms of gene and protein classification, driving forces, substrate specificities and cellular localization. When targeting absorptive large capacity membrane transporters in the small intestine in order to increase oral bioavailabilities of drug or prodrug, the major influence on in vivo pharmacokinetics is suggested to be dose-dependent increase in bioavailability as well as prolonged blood circulation due to large capacity facilitated absorption, and renal re-absorption, respectively. In contrast, when targeting low-capacity transporters such as vitamin transporters, dose independent saturable absorption kinetics are suggested. We thus believe that targeting drug substrates for absorptive intestinal membrane transporters could be a feasible strategy for optimizing drug bioavailability and distribution.
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Affiliation(s)
- Bente Steffansen
- Department of Pharmaceutics, The Danish University of Pharmaceutical Sciences, 2 Universitetsparken, DK-2100 Copenhagen, Denmark.
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