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Buxhofer-Ausch V, Német O, Sheikh M, Andrikovics H, Reiner A, Ausch C, Mechtcheriakova D, Tordai A, Gleiss A, Özvegy-Laczka C, Jäger W, Thalhammer T. Two common polymorphic variants of OATP4A1 as potential risk factors for colorectal cancer. Oncol Lett 2020; 20:252. [PMID: 32994815 PMCID: PMC7509609 DOI: 10.3892/ol.2020.12115] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 08/03/2020] [Indexed: 12/17/2022] Open
Abstract
Genetic variations in the organic-anion-transporting polypeptide (OATP)-encoding solute carrier of organic anions (SLCO) genes can promote cancer development and progression. The overexpression of solute carrier organic anion transporter family member 4A1 (OATP4A1), a transporter for steroid hormones, prostaglandins, and bile acids, has been previously associated with tumor recurrence and progression in colorectal cancer (CRC). Therefore, the present study aimed to investigate the association between 2 frequent single nucleotide polymorphisms (SNPs) in SLCO4A1 (rs34419428, R70Q; rs1047099G, V78I) and CRC predisposition. Following restriction fragment length polymorphism-PCR analysis in 178 patients with CRC [Union for International Cancer Control (UICC) stage I/II] and 65 healthy controls, no significant difference was observed in allele frequency and the number of heterozygous/homozygous individuals between the groups. Notably, the R70Q minor allele was identified to be associated with the V78I minor allele in the genome. Comparing of the individual genotypes of CRC patients to clinical data, including sex, UICC-stage and relapse revealed no increased risk for CRC. In addition, the OATP4A1 immunoreactivity assay in paraffin-embedded CRC and adjacent non-tumorous mucosa sections, examined using quantitative microscopy image analysis, did not reveal any association with these polymorphisms. No significant differences were observed in the expression levels, localization, and sodium fluorescein transport capacity among the OATP4A1 variants, which was studied using functional assays in Sf9-insect and A431 tumor cells overexpressing the 2 single and a double mutant OATP4A1 SNP variants. These results suggested that the 2 most frequent polymorphisms located in the first intracellular loop of OATP4A1 do not associate with CRC predisposition and tumor recurrence. They are unlikely to affect the outcome of CRC in patients.
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Affiliation(s)
- Veronika Buxhofer-Ausch
- Department of Internal Medicine I with Hematology, Stem Cell Transplantation, Hemostaseology and Medical Oncology, Ordensklinikum Linz der Elisabethinen, A-4020 Linz, Austria.,Medical Faculty, Johannes Kepler University Linz, A-4040 Linz, Austria
| | - Orsolya Német
- Membrane Protein Research Group, Institute of Enzymology, Research Centre for Natural Sciences, H-1117 Budapest, Hungary
| | - Majdah Sheikh
- Institute of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, A-1090 Vienna, Austria
| | - Hajnalka Andrikovics
- Laboratory of Molecular Genetics, National Institute of Hematology and Infectious Diseases, Central Hospital of Southern Pest, H-1097 Budapest, Hungary
| | - Angelika Reiner
- Department of Pathology, Donauspital/Sozialmedizinisches Zentrum Ost, A-1220 Vienna, Austria
| | - Christoph Ausch
- Department of Surgery, Krankenhaus Göttlicher Heiland, A-1170 Vienna, Austria
| | - Diana Mechtcheriakova
- Institute of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, A-1090 Vienna, Austria
| | - Attila Tordai
- Institute of Pathophysiology, Semmelweis University, Faculty of Medicine, H-1085 Budapest, Hungary
| | - Andreas Gleiss
- Center for Medical Statistics, Informatics, and Intelligent Systems, Medical University of Vienna, A-1090 Vienna, Austria
| | - Csilla Özvegy-Laczka
- Membrane Protein Research Group, Institute of Enzymology, Research Centre for Natural Sciences, H-1117 Budapest, Hungary
| | - Walter Jäger
- Department of Pharmaceutical Chemistry, University of Vienna, A-1090 Vienna, Austria
| | - Theresia Thalhammer
- Institute of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, A-1090 Vienna, Austria
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Zemanová L, Navrátilová H, Andrýs R, Šperková K, Andrejs J, Kozáková K, Meier M, Möller G, Novotná E, Šafr M, Adamski J, Wsól V. Initial characterization of human DHRS1 (SDR19C1), a member of the short-chain dehydrogenase/reductase superfamily. J Steroid Biochem Mol Biol 2019; 185:80-89. [PMID: 30031147 DOI: 10.1016/j.jsbmb.2018.07.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 07/05/2018] [Accepted: 07/17/2018] [Indexed: 11/28/2022]
Abstract
Many enzymes from the short-chain dehydrogenase/reductase superfamily (SDR) have already been well characterized, particularly those that participate in crucial biochemical reactions in the human body (e.g. 11β-hydroxysteroid dehydrogenase 1, 17β-hydroxysteroid dehydrogenase 1 or carbonyl reductase 1). Several other SDR enzymes are completely or almost completely uncharacterized, such as DHRS1 (also known as SDR19C1). Based on our in silico and experimental approaches, DHRS1 is described as a likely monotopic protein that interacts with the membrane of the endoplasmic reticulum. The highest expression level of DHRS1 protein was observed in human liver and adrenals. The recombinant form of DHRS1 was purified using the detergent n-dodecyl-β-D-maltoside, and DHRS1 was proven to be an NADPH-dependent reductase that is able to catalyse the in vitro reductive conversion of some steroids (estrone, androstene-3,17-dione and cortisone), as well as other endogenous substances and xenobiotics. The expression pattern and enzyme activities fit to a role in steroid and/or xenobiotic metabolism; however, more research is needed to fully clarify the exact biological function of DHRS1.
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Affiliation(s)
- Lucie Zemanová
- Department of Biochemical Sciences, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovskeho 1203, 500 05 Hradec Kralove, Czech Republic.
| | - Hana Navrátilová
- Department of Biochemical Sciences, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovskeho 1203, 500 05 Hradec Kralove, Czech Republic
| | - Rudolf Andrýs
- Department of Chemistry, Faculty of Science, University of Hradec Kralove, Rokitanskeho 62, 500 03 Hradec Kralove, Czech Republic
| | - Kristýna Šperková
- Department of Biochemical Sciences, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovskeho 1203, 500 05 Hradec Kralove, Czech Republic
| | - Jiří Andrejs
- Department of Biochemical Sciences, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovskeho 1203, 500 05 Hradec Kralove, Czech Republic
| | - Klára Kozáková
- Department of Biochemical Sciences, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovskeho 1203, 500 05 Hradec Kralove, Czech Republic
| | - Marc Meier
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Experimental Genetics, Genome Analysis Center, Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany
| | - Gabriele Möller
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Experimental Genetics, Genome Analysis Center, Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany
| | - Eva Novotná
- Department of Biochemical Sciences, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovskeho 1203, 500 05 Hradec Kralove, Czech Republic
| | - Miroslav Šafr
- Institute of Legal Medicine, Faculty of Medicine in Hradec Králové, Charles University and University Hospital in Hradec Králové, Sokolská 581, 500 05 Hradec Kralove, Czech Republic
| | - Jerzy Adamski
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Experimental Genetics, Genome Analysis Center, Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany; Lehrstuhl für Experimentelle Genetik, Technische Universität München, 85350 Freising-Weihenstephan, Germany; German Center for Diabetes Research (DZD), Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany
| | - Vladimír Wsól
- Department of Biochemical Sciences, Faculty of Pharmacy in Hradec Králové, Charles University, Heyrovskeho 1203, 500 05 Hradec Kralove, Czech Republic
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Role of OATP transporters in steroid uptake by prostate cancer cells in vivo. Prostate Cancer Prostatic Dis 2016; 20:20-27. [PMID: 27645128 PMCID: PMC5762123 DOI: 10.1038/pcan.2016.42] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 06/26/2016] [Accepted: 07/25/2016] [Indexed: 02/06/2023]
Abstract
BACKGROUND Epidemiologic and in vitro studies suggest that SLCO-encoded organic anion transporting polypeptide (OATP) transporters influence the response of prostate cancer (PCa) to androgen deprivation by altering intratumor androgens. We have previously shown that castration-resistant metastases express multiple SLCO transporters at significantly higher levels than primary PCa, suggesting that OATP-mediated steroid transport is biologically relevant in advanced disease. However, whether OATP-mediated steroid transport can actually modify prostate tumor androgen levels in vivo has never been demonstrated. METHODS We sought to determine whether OATP-mediated steroid transport can measurably alter PCa androgen levels in vivo. We evaluated the uptake of dehydroepiandrosterone (DHEAS), E1S and testosterone in LNCaP cells engineered to express OATP1B1, 1B3, 2B1 or 4A1. We measured the uptake via administration of tritiated steroids to castrate mice bearing vector control or OATP1B1-, 2B1- or 4A1-expressing xenografts. We treated tumor-bearing mice with DHEAS and testosterone at physiologically relevant levels and measured intratumor accumulation of administered steroids by mass spectrometry. RESULTS OATP1B1- and 2B-expressing xenografts each showed a threefold increase in tritiated-DHEAS uptake vs vector controls (P=0.002 and P=0.036, respectively). At circulating DHEAS levels similar to those in abiraterone-treated men (~15 μg dl-1), OATP1B1- and 2B1-expressing xenografts showed a 3.9-fold (P=0.057) and 1.9-fold (P=0.048) increase in tumor accumulation of DHEAS and a 1.6-fold (P=0.057) and 2.7-fold (P=0.095) increase in DHEA, respectively. At the substantial circulating testosterone levels found in eugonadal men, a consistent effect of OATP1B1, 2B1 or 4A1 on testosterone uptake in vivo was not detected. CONCLUSIONS OATP transporters measurably alter DHEAS uptake and intratumor androgen levels in prostate tumors in vivo, even at circulating androgen levels achieved in abiraterone-treated patients. These novel data emphasize the continued need to inhibit ligand-mediated androgen receptor signaling in PCa tumors, and support prospective evaluation of studies designed to test inhibition of OATP-mediated DHEAS uptake and utilization.
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Patik I, Kovacsics D, Német O, Gera M, Várady G, Stieger B, Hagenbuch B, Szakács G, Özvegy-Laczka C. Functional expression of the 11 human Organic Anion Transporting Polypeptides in insect cells reveals that sodium fluorescein is a general OATP substrate. Biochem Pharmacol 2015; 98:649-58. [PMID: 26415544 DOI: 10.1016/j.bcp.2015.09.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 09/17/2015] [Indexed: 11/29/2022]
Abstract
Organic Anion Transporting Polypeptides (OATPs), encoded by genes of the Solute Carrier Organic Anion (SLCO) family, are transmembrane proteins involved in the uptake of various compounds of endogenous or exogenous origin. In addition to their physiological roles, OATPs influence the pharmacokinetics and drug-drug interactions of several clinically relevant compounds. To examine the function and molecular interactions of human OATPs, including several poorly characterized family members, we expressed all 11 human OATPs at high levels in the baculovirus-Sf9 cell system. We measured the temperature- and inhibitor-sensitive cellular accumulation of sodium fluorescein and fluorescein-methotrexate, two fluorescent substrates of the OATPs, OATP1B1 and 1B3. OATP1B1 and 1B3 were functional in Sf9 cells, showing rapid uptake (t1/2(fluorescein-methotrexate) 2.64 and 4.16 min, and t1/2(fluorescein) 6.71 and 5.58 min for OATP1B1 and 1B3, respectively) and high-affinity transport (Km(fluorescein-methotrexate) 0.23 and 0.53 μM, and Km(fluorescein) 25.73 and 38.55 μM for OATP1B1 and 1B3, respectively) of both substrates. We found that sodium fluorescein is a general substrate of all human OATPs: 1A2, 1B1, 1B3, 1C1, 2A1, 2B1, 3A1, 4A1, 4C1, 5A1 and 6A1, while fluorescein-methotrexate is only transported by 1B1, 1B3, 1A2 and 2B1. Acidic extracellular pH greatly facilitated fluorescein uptake by all OATPs, and new molecular interactions were detected (between OATP2B1 and Imatinib, OATP3A1, 5A1 and 6A1 and estradiol 17-β-d-glucuronide, and OATP1C1 and 4C1 and prostaglandin E2). These studies demonstrate, for the first time, that the insect cell system is suitable for the functional analysis of the entire human OATP family, and for drug-OATP interaction screening.
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Affiliation(s)
- Izabel Patik
- Momentum Membrane Protein Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok krt. 2, H-1117 Budapest, Hungary
| | - Daniella Kovacsics
- Momentum Membrane Protein Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok krt. 2, H-1117 Budapest, Hungary
| | - Orsolya Német
- Momentum Membrane Protein Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok krt. 2, H-1117 Budapest, Hungary
| | - Melinda Gera
- Momentum Membrane Protein Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok krt. 2, H-1117 Budapest, Hungary
| | - György Várady
- Laboratory of Molecular Cell Biology, Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok krt. 2, H-1117 Budapest, Hungary
| | - Bruno Stieger
- Department of Clinical Pharmacology and Toxicology, University Hospital, 8091 Zurich, Switzerland
| | - Bruno Hagenbuch
- Department of Pharmacology, Toxicology and Therapeutics, The University of Kansas Medical Center, Kansas City, KA 66160, USA
| | - Gergely Szakács
- Momentum Membrane Protein Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok krt. 2, H-1117 Budapest, Hungary
| | - Csilla Özvegy-Laczka
- Momentum Membrane Protein Research Group, Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok krt. 2, H-1117 Budapest, Hungary.
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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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Popovic M, Zaja R, Fent K, Smital T. Molecular characterization of zebrafish Oatp1d1 (Slco1d1), a novel organic anion-transporting polypeptide. J Biol Chem 2013; 288:33894-33911. [PMID: 24126916 DOI: 10.1074/jbc.m113.518506] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The organic anion-transporting polypeptide (OATP/Oatp) superfamily includes a group of polyspecific transporters that mediate transport of large amphipathic, mostly anionic molecules across cell membranes of eukaryotes. OATPs/Oatps are involved in the disposition and elimination of numerous physiological and foreign compounds. However, in non-mammalian species, the functional properties of Oatps remain unknown. We aimed to elucidate the role of Oatp1d1 in zebrafish to gain insights into the functional and structural evolution of the OATP1/Oatp1 superfamily. We show that diversification of the OATP1/Oatp1 family occurs after the emergence of jawed fish and that the OATP1A/Oatp1a and OATP1B/Oatp1b subfamilies appeared at the root of tetrapods. The Oatp1d subfamily emerged in teleosts and is absent in tetrapods. The zebrafish Oatp1d1 is similar to mammalian OATP1A/Oatp1a and OATP1B/Oatp1b members, with the main physiological role in transport and balance of steroid hormones. Oatp1d1 activity is dependent upon pH gradient, which could indicate bicarbonate exchange as a mode of transport. Our analysis of evolutionary conservation and structural properties revealed that (i) His-79 in intracellular loop 3 is conserved within OATP1/Oatp1 family and is crucial for the transport activity; (ii) N-glycosylation impacts membrane targeting and is conserved within the OATP1/Oatp1 family with Asn-122, Asn-133, Asn-499, and Asn-512 residues involved; (iii) the evolutionarily conserved cholesterol recognition interaction amino acid consensus motif is important for membrane localization; and (iv) Oatp1d1 is present in dimeric and possibly oligomeric form in the cell membrane. In conclusion, we describe the first detailed characterization of a new Oatp transporter in zebrafish, offering important insights into the functional evolution of the OATP1/Oatp1 family and the physiological role of Oatp1d1.
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Affiliation(s)
- Marta Popovic
- Laboratory for Molecular Ecotoxicology, Division for Marine and Environmental Research, Rudjer Boskovic Institute, Bijenicka 54, 10 000 Zagreb, Croatia
| | - Roko Zaja
- Laboratory for Molecular Ecotoxicology, Division for Marine and Environmental Research, Rudjer Boskovic Institute, Bijenicka 54, 10 000 Zagreb, Croatia
| | - Karl Fent
- School of Life Sciences, University of Applied Sciences Northwestern Switzerland, Gründenstrasse 40, CH-4132 Muttenz, Switzerland; Department of Environmental System Sciences, Swiss Federal Institute of Technology (ETHZ), CH-8092 Zürich, Switzerland
| | - Tvrtko Smital
- Laboratory for Molecular Ecotoxicology, Division for Marine and Environmental Research, Rudjer Boskovic Institute, Bijenicka 54, 10 000 Zagreb, Croatia.
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Large scale expression and purification of mouse melanopsin-L in the baculovirus expression system. Protein Expr Purif 2013; 91:134-46. [PMID: 23921072 DOI: 10.1016/j.pep.2013.07.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 07/14/2013] [Accepted: 07/17/2013] [Indexed: 11/22/2022]
Abstract
Melanopsin is the mammalian photopigment that primarily mediates non-visual photoregulated physiology. So far, this photopigment is poorly characterized with respect to structure and function. Here, we report large-scale production and purification of the intact long isoform of mouse melanopsin (melanopsin-L) using the baculovirus/insect cell expression system. Exploiting the baculoviral GP67 signal peptide, we obtained expression levels that varied between 10-30pmol/10(6)cells, equivalent to 2-5mg/L. This could be further enhanced using DMSO as a chemical chaperone. LC-MS analysis confirmed that full-length melanopsin-L was expressed and demonstrated that the majority of the expressed protein was N-glycosylated at Asn(30) and Asn(34). Other posttranslational modifications were not yet detected. Purification was achieved exploiting a C-terminal deca-histag, realizing a purification factor of several hundred-fold. The final recovery of purified melanopsin-L averaged 2.5% of the starting material. This was mainly due to low extraction yields, probably since most of the protein was present as the apoprotein. The spectral data we obtained agree with an absorbance maximum in the 460-500nm wavelength region and a significant red-shift upon illumination. This is the first report on expression and purification of full length melanopsin-L at a scale that can easily be further amplified.
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Ji C, Tschantz WR, Pfeifer ND, Ullah M, Sadagopan N. Development of a multiplex UPLC-MRM MS method for quantification of human membrane transport proteins OATP1B1, OATP1B3 and OATP2B1 in in vitro systems and tissues. Anal Chim Acta 2011; 717:67-76. [PMID: 22304817 DOI: 10.1016/j.aca.2011.12.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Revised: 12/02/2011] [Accepted: 12/05/2011] [Indexed: 11/25/2022]
Abstract
OATP1B1, OATP1B3 and OATP2B1 are important members of the organic anion transporting polypeptides (OATP) family and are implicated in the hepatic disposition of endobiotics and xenobiotics. Quantitating the expression levels of human OATP1B1, OATP1B3 and OATP2B1 in in vitro systems and tissue samples could significantly improve attempts to scale up in vitro data and result in more effective in vitro-in vivo correlation of transporter-mediated effects on drug disposition, such as hepatic clearance. In the present study, a quantification method was developed, characterized, and implemented for simultaneous determination of human OATP1B1, OATP1B3 and OATP2B1 in HEK cells transfected with OATP-expressing plasmid vectors (SLCO1B1, SLCO1B3, and SLCO2B1, respectively), human hepatocytes, human brain capillary endothelial cells, and humanized mouse liver tissue using UPLC-MRM MS. Purified membrane protein standards prepared and characterized as previously reported (Protein Expr. Purif. 2008, 57, 163-71) were first used as standards for absolute quantification of the expression levels of the three human OATP membrane proteins. The specificity of the optimized MRM transitions were characterized by analyzing the tryptic digests of the membrane protein fraction of wild type HEK cells and control mouse liver tissue using the herein reported UPLC-MRM MS method. The linearity of the calibration curve spanned from 0.2 μg mL(-1) (0.040 μg mg(-1)) to 20 μg mL(-1) (4.0 μg mg(-1)), with accuracy (% RE) within 15% at all concentrations examined for all three OATPs of interest in this study. The intra- and inter-day assay accuracy (% RE) and coefficient of variations (% CV) of triplicates are all within 15% for all levels of quality control samples prepared by mixing the membrane fraction of control mouse liver tissue with the required amount of purified human OATP1B1, OATP1B3 and OATP2B1.
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Affiliation(s)
- Chengjie Ji
- Pfizer Global Research and Development, Andover/Cambridge Laboratories, Andover, MA 01810, USA.
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Pomari E, Nardi A, Fiore C, Celeghin A, Colombo L, Dalla Valle L. Transcriptional control of human organic anion transporting polypeptide 2B1 gene. J Steroid Biochem Mol Biol 2009; 115:146-52. [PMID: 19383542 DOI: 10.1016/j.jsbmb.2009.04.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2008] [Revised: 03/31/2009] [Accepted: 04/08/2009] [Indexed: 01/13/2023]
Abstract
Organic anion transporting polypeptides (OATPs) are a group of transmembrane carriers with a wide spectrum of amphipathic substrates. In particular, OATP2B1 (previously called OATP-B) can transport steroid hormone conjugates and is expressed in organs with steroidogenic activity, such as placenta, brain and skin. In this work, we have analyzed the transcription of the OATP2B1 gene (SLCO2B1) in 14 different human tissues by means of 5'-RACE analysis. Five promoters (only two of which were present in GenBank), associated with distinct first exons, were found to drive OATP2B1 expression, giving rise to transcripts with unique 5'-untranslated termini. Exon 1b is widely expressed and was found here in 10 tissues. It is partially coding, while the other four different first exons are untranslated. All exons are spliced to a common exon 2 that contains a putative ATG in frame with the following coding region. Sequence analysis of the 5'-flanking region of each first exon revealed a lack of TATA box, thus accounting for the use of multiple transcriptional start sites in nearly all first exons.
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Affiliation(s)
- Elena Pomari
- Comparative Endocrinology Laboratory, Department of Biology, University of Padova, Via U. Bassi 58/B, 35131 Padova, Italy
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Yang Y, Hu Z, Liu Z, Wang Y, Chen X, Chen G. High human GLUT1, GLUT2, and GLUT3 expression in Schizosaccharomyces pombe. BIOCHEMISTRY (MOSCOW) 2009; 74:75-80. [DOI: 10.1134/s0006297909010118] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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