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Du T, Luo T, Wang J, Sun R, Cai H. Role of MRPs transporters in pharmacokinetics and intestinal toxicity of irinotecan. Food Chem Toxicol 2023; 182:114171. [PMID: 37956707 DOI: 10.1016/j.fct.2023.114171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Revised: 10/21/2023] [Accepted: 11/01/2023] [Indexed: 11/15/2023]
Abstract
To identify additional genetic markers contributing to variability in CPT-11 disposition and toxicity, we assessed impact of the multiple drug-resistant transporters 1, 2, and 3 (MRP1, MRP2, and MRP3) on the intestinal toxicity, pharmacokinetics, tissue distribution and biliary excretion of CPT-11 using a knockout mouse model. Mrp1/3 knockout had minor impact on intestinal toxicity of CPT-11, tissue distribution, biliary excretion, and PK parameter of its active metabolites SN38. Conversely, Mrp2-/- mice, with low carboxylesterase activity, displayed insensitivity to CPT-11 toxicity due to reduced intestinal exposure to SN38. In PK studies, Mrp1/2 knockout significantly increased the AUC of CPT-11 compared to their AUC in FVB mice. However, the AUC of SN38 in Mrp2 -/- mice was decreased by 3.25-fold. Mrp3 knockout only slightly increased SN38 plasma exposure. Lastly, Mrp2/3 knockout increased biliary excretion amount of CPT-11 by 67.2% and 48.5% compared to wild-type mice, respectively. Consequently, Mrp1/3 deficiency didn't change SN38 tissue distribution. Finally, correlation analysis demonstrated that tissue exposure to SN38 was better correlated with toxicity than plasma AUC of SN38. Mrp1/2/3 deficiency showed a minor impact on PK, biliary excretion, distribution and intestinal exposure of SN38, and as a result, did not affect the intestinal toxicity of CPT-11.
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Affiliation(s)
- Ting Du
- Hubei Key Laboratory of Wudang Local Chinese Medicine Research, Taihe Hospital, Hubei University of Medicine, Shiyan, 442000, China
| | - Tao Luo
- Hubei Key Laboratory of Wudang Local Chinese Medicine Research, Taihe Hospital, Hubei University of Medicine, Shiyan, 442000, China
| | - Junwen Wang
- Jiangxi Guhan Refined Chinese Herbal Pieces Co., Ltd., Nanchang, 330041, China
| | - Rongjin Sun
- Hubei Key Laboratory of Wudang Local Chinese Medicine Research, Taihe Hospital, Hubei University of Medicine, Shiyan, 442000, China; Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, 4349 Martin Luther King Boulevard, Houston, TX, 77204, United States.
| | - Hua Cai
- Hubei Key Laboratory of Wudang Local Chinese Medicine Research, Taihe Hospital, Hubei University of Medicine, Shiyan, 442000, China.
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2
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Hanssen KM, Haber M, Fletcher JI. Targeting multidrug resistance-associated protein 1 (MRP1)-expressing cancers: Beyond pharmacological inhibition. Drug Resist Updat 2021; 59:100795. [PMID: 34983733 DOI: 10.1016/j.drup.2021.100795] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 08/30/2021] [Accepted: 09/05/2021] [Indexed: 12/30/2022]
Abstract
Resistance to chemotherapy remains one of the most significant obstacles to successful cancer treatment. While inhibiting drug efflux mediated by ATP-binding cassette (ABC) transporters is a seemingly attractive and logical approach to combat multidrug resistance (MDR), small molecule inhibition of ABC transporters has so far failed to confer clinical benefit, despite considerable efforts by medicinal chemists, biologists, and clinicians. The long-sought treatment to eradicate cancers displaying ABC transporter overexpression may therefore lie within alternative targeting strategies. When aberrantly expressed, the ABC transporter multidrug resistance-associated protein 1 (MRP1, ABCC1) confers MDR, but can also shift cellular redox balance, leaving the cell vulnerable to select agents. Here, we explore the physiological roles of MRP1, the rational for targeting this transporter in cancer, the development of small molecule MRP1 inhibitors, and the most recent developments in alternative therapeutic approaches for targeting cancers with MRP1 overexpression. We discuss approaches that extend beyond simple MRP1 inhibition by exploiting the collateral sensitivity to glutathione depletion and ferroptosis, the rationale for targeting the shared transcriptional regulators of both MRP1 and glutathione biosynthesis, advances in gene silencing, and new molecules that modulate transporter activity to the detriment of the cancer cell. These strategies illustrate promising new approaches to address multidrug resistant disease that extend beyond the simple reversal of MDR and offer exciting routes for further research.
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Affiliation(s)
- Kimberley M Hanssen
- Children's Cancer Institute Australia, Lowy Cancer Research Centre, UNSW Sydney, Sydney, NSW, Australia; School of Women's and Children's Health, UNSW Sydney, Sydney, NSW, Australia
| | - Michelle Haber
- Children's Cancer Institute Australia, Lowy Cancer Research Centre, UNSW Sydney, Sydney, NSW, Australia; School of Women's and Children's Health, UNSW Sydney, Sydney, NSW, Australia
| | - Jamie I Fletcher
- Children's Cancer Institute Australia, Lowy Cancer Research Centre, UNSW Sydney, Sydney, NSW, Australia; School of Women's and Children's Health, UNSW Sydney, Sydney, NSW, Australia.
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Villanueva S, Zhang W, Zecchinati F, Mottino A, Vore M. ABC Transporters in Extrahepatic Tissues: Pharmacological Regulation in Heart and Intestine. Curr Med Chem 2019; 26:1155-1184. [PMID: 29589524 DOI: 10.2174/0929867325666180327092639] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 02/26/2018] [Accepted: 03/09/2018] [Indexed: 12/17/2022]
Abstract
ATP binding cassette (ABC) transporters are transmembrane proteins expressed in secretory epithelia like the liver, kidneys and intestine, in the epithelia exhibiting barrier function such as the blood-brain barrier and placenta, and to a much lesser extent, in tissues like reproductive organs, lungs, heart and pancreas, among others. They regulate internal distribution of endogenous metabolites and xenobiotics including drugs of therapeutic use and also participate in their elimination from the body. We here describe the function and regulation of ABC transporters in the heart and small intestine, as examples of extrahepatic tissues, in which ABC proteins play clearly different roles. In the heart, they are involved in tissue pathogenesis as well as in protecting this organ against toxic compounds and druginduced oxidative stress. The small intestine is highly exposed to therapeutic drugs taken orally and, consequently, ABC transporters localized on its surface strongly influence drug absorption and pharmacokinetics. Examples of the ABC proteins currently described are Multidrug Resistance-associated Proteins 1 and 2 (MRP1 and 2) for heart and small intestine, respectively, and P-glycoprotein (P-gp) and Breast Cancer Resistance Protein (BCRP) for both organs.
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Affiliation(s)
- Silvina Villanueva
- Instituto de Fisiologia Experimental, Facultad de Ciencias Bioquimicas y Farmaceuticas, CONICET-UNR. 2000 Rosario, Argentina
| | - Wei Zhang
- Department of Toxicology & Cancer Biology, University of Kentucky, Lexington, KY 40536-0305, United States
| | - Felipe Zecchinati
- Instituto de Fisiologia Experimental, Facultad de Ciencias Bioquimicas y Farmaceuticas, CONICET-UNR. 2000 Rosario, Argentina
| | - Aldo Mottino
- Instituto de Fisiologia Experimental, Facultad de Ciencias Bioquimicas y Farmaceuticas, CONICET-UNR. 2000 Rosario, Argentina
| | - Mary Vore
- Department of Toxicology & Cancer Biology, University of Kentucky, Lexington, KY 40536-0305, United States
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In Vitro Mechanistic Study of the Distribution of Lascufloxacin into Epithelial Lining Fluid. Antimicrob Agents Chemother 2019; 63:AAC.02208-18. [PMID: 30718243 DOI: 10.1128/aac.02208-18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 01/25/2019] [Indexed: 11/20/2022] Open
Abstract
The present study aimed to clarify the mechanism underlying the high distribution of lascufloxacin in epithelial lining fluid (ELF). Involvement of transporters was examined by transcellular transport across Calu-3 and transporter-overexpressing cells; the binding of lascufloxacin to ELF components was examined by an organic solvent-water partitioning system that employed pulmonary surfactant and phospholipids. Transcellular transport across the transporter-overexpressing cells indicated lascufloxacin to be a substrate of both P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP); therefore, its transport across Calu-3 cells was inhibited by P-gp and BCRP inhibitors. However, permeability and efflux ratios of lascufloxacin were similar to those of the other quinolones with relatively low ELF distribution, indicating the existence of another mechanism for lascufloxacin distribution in ELF. Amongst pulmonary surfactants, which are a primary component of ELF, lascufloxacin preferentially bound to phosphatidylserine (PhS) from several phospholipids, and the binding was significantly greater than that for other quinolones. This binding was saturable with two apparent classes of binding sites and inhibited by some weakly basic drugs, indicating the presence of an ionic bond. In conclusion, the results of this study suggest that the binding of lascufloxacin to PhS in the pulmonary surfactant is the major mechanism of the high distribution of lascufloxacin in the ELF.
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Stefan SM, Wiese M. Small-molecule inhibitors of multidrug resistance-associated protein 1 and related processes: A historic approach and recent advances. Med Res Rev 2018; 39:176-264. [DOI: 10.1002/med.21510] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 04/05/2018] [Accepted: 04/28/2018] [Indexed: 12/19/2022]
Affiliation(s)
- Sven Marcel Stefan
- Pharmaceutical Institute; Rheinische Friedrich-Wilhelms-University; Bonn Germany
| | - Michael Wiese
- Pharmaceutical Institute; Rheinische Friedrich-Wilhelms-University; Bonn Germany
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Nagar S, Tucker J, Weiskircher EA, Bhoopathy S, Hidalgo IJ, Korzekwa K. Compartmental models for apical efflux by P-glycoprotein--part 1: evaluation of model complexity. Pharm Res 2014; 31:347-59. [PMID: 24019023 PMCID: PMC3946900 DOI: 10.1007/s11095-013-1164-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Accepted: 07/28/2013] [Indexed: 01/16/2023]
Abstract
PURPOSE With the goal of quantifying P-gp transport kinetics, Part 1 of these manuscripts evaluates different compartmental models and Part 2 applies these models to kinetic data. METHODS Models were developed to simulate the effect of apical efflux transporters on intracellular concentrations of six drugs. The effect of experimental variability on model predictions was evaluated. Several models were evaluated, and characteristics including membrane configuration, lipid content, and apical surface area (asa) were varied. RESULTS Passive permeabilities from MDCK-MDR1 cells in the presence of cyclosporine gave lower model errors than from MDCK control cells. Consistent with the results in Part 2, model configuration had little impact on calculated model errors. The 5-compartment model was the simplest model that reproduced experimental lag times. Lipid content and asa had minimal effect on model errors, predicted lag times, and intracellular concentrations. Including endogenous basolateral uptake activity can decrease model errors. Models with and without explicit membrane barriers differed markedly in their predicted intracellular concentrations for basolateral drug exposure. Single point data resulted in clearances similar to time course data. CONCLUSIONS Compartmental models are useful to evaluate the impact of efflux transporters on intracellular concentrations. Whereas a 3-compartment model may be sufficient to predict the impact of transporters that efflux drugs from the cell, a 5-compartment model with explicit membranes may be required to predict intracellular concentrations when efflux occurs from the membrane. More complex models including additional compartments may be unnecessary.
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Affiliation(s)
- Swati Nagar
- Department of Pharmaceutical Sciences, Temple University School of Pharmacy, Philadelphia PA
| | - Jalia Tucker
- Department of Pharmaceutical Sciences, Temple University School of Pharmacy, Philadelphia PA
| | | | | | | | - Ken Korzekwa
- Department of Pharmaceutical Sciences, Temple University School of Pharmacy, Philadelphia PA
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Lees P. Pharmacokinetics, pharmacodynamics and therapeutics of pradofloxacin in the dog and cat. J Vet Pharmacol Ther 2013; 36:209-21. [PMID: 23406008 DOI: 10.1111/jvp.12036] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 01/09/2013] [Indexed: 11/29/2022]
Abstract
Pradofloxacin is a third-generation fluoroquinolone, licensed in the EU for use in a range of indications in the dog and cat and authorized more recently in the USA for one therapeutic indication (skin infections) in the cat. This review summarizes and appraises current knowledge on the physico-chemical, pharmacological [pharmacokinetics (PK) and pharmacodynamics (PD)], safety and therapeutic properties of pradofloxacin in the target species. Pradofloxacin contains two centres of asymmetry and is the pure SS enantiomer. After oral dosing of tablets (dog) or tablets and oral suspension (cat), maximum plasma concentrations (Cmax ) are achieved in less than 3.0 h, and terminal half-life is of the order of 5-10 h. Accumulation is slight or absent with once daily oral dosing. Free drug concentrations in plasma are in the range of 63-71% of total concentration. As for other fluoroquinolones, antibacterial activity is attributable to inhibition of bacterial replication at two sites, subunit A of topoisomerase II and topoisomerase IV. The antimicrobial spectrum includes gram-negative and gram-positive organisms, anaerobes, Mycoplasma spp. and some intracellular organisms (Rickettsia spp. and Mycobacterium spp.). The killing action is of the concentration-dependent type. Pradofloxacin has high potency (low MIC values) in comparison with first- and second-generation fluoroquinolones. Integration of in vivo PK and in vitro PD data provides values of Cmax /MIC and area under plasma concentration-time curve (AUC24 h )/MIC ratios predictive of good clinical efficacy against sensitive organisms, when administered at recommended dose rates. Clinical trial evaluation of pradofloxacin, in comparison with other authorized antimicrobial drugs, has demonstrated either noninferiority or superiority of pradofloxacin. Data indicating clinical and, in some instances, bacteriological cure have been reported: (i) in cats, for wound infections, abscesses, upper respiratory tract infections, conjunctivitis, feline infectious anaemia and lower urinary tract infections and (ii) in dogs, for wound infections, superficial and deep pyoderma, acute urinary tract infections and adjunctive treatment of infections of gingival and periodontal tissues. At clinical dose rates pradofloxacin was well tolerated in preclinical studies and in clinical trials. Among the advantages of pradofloxacin are (i) successful treatment of infections caused by strains resistant to some other fluoroquinolones, as predicted by PK/PD data, but depending on the specific MIC of the target strain and (ii) a reduced propensity for resistance development based on MPC measurements. The preclinical and clinical data on pradofloxacin suggest that this drug should commonly be the fluoroquinolone of choice when a drug of this class is indicated. However, the PK/PD data on pradofloxacin, in comparison with other fluoroquinolones, are not a factor that leads automatically to greater clinical efficacy.
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Affiliation(s)
- P Lees
- Royal Veterinary College, Hawkshead Campus, Hertfordshire, UK
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Jin HE, Song B, Kim SB, Shim WS, Kim DD, Chong S, Chung SJ, Shim CK. Transport of gemifloxacin, a 4th generation quinolone antibiotic, in the Caco-2 and engineered MDCKII cells, and potential involvement of efflux transporters in the intestinal absorption of the drug. Xenobiotica 2012; 43:355-67. [DOI: 10.3109/00498254.2012.720740] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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9
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Broccatelli F, Mannhold R, Moriconi A, Giuli S, Carosati E. QSAR modeling and data mining link Torsades de Pointes risk to the interplay of extent of metabolism, active transport, and HERG liability. Mol Pharm 2012; 9:2290-301. [PMID: 22742658 DOI: 10.1021/mp300156r] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
We collected 1173 hERG patch clamp (PC) data (IC50) from the literature to derive twelve classification models for hERG inhibition, covering a large variety of chemical descriptors and classification algorithms. Models were generated using 545 molecules and validated through 258 external molecules tested in PC experiments. We also evaluated the suitability of the best models to predict the activity of 26 proprietary compounds tested in radioligand binding displacement (RBD). Results proved the necessity to use multiple validation sets for a true estimation of model accuracy and demonstrated that using various descriptors and algorithms improves the performance of ligand-based models. Intriguingly, one of the most accurate models uncovered an unexpected link between extent of metabolism and hERG liability. This hypothesis was fairly reinforced by using the Biopharmaceutics Drug Disposition Classification System (BDDCS) that recognized 94% of the hERG inhibitors as extensively metabolized in vivo. Data mining suggested that high Torsades de Pointes (TdP) risk results from an interplay of hERG inhibition, extent of metabolism, active transport, and possibly solubility. Overall, these new findings might improve both the decision making skills of pharmaceutical scientists to mitigate hERG liability during the drug discovery process and the TdP risk assessment during drug development.
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Affiliation(s)
- Fabio Broccatelli
- Laboratory for Chemometrics and Cheminformatics, Chemistry Department, University of Perugia, Via Elce di Sotto 10, I-06123 Perugia, Italy
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Mulgaonkar A, Venitz J, Sweet DH. Fluoroquinolone disposition: identification of the contribution of renal secretory and reabsorptive drug transporters. Expert Opin Drug Metab Toxicol 2012; 8:553-69. [PMID: 22435536 DOI: 10.1517/17425255.2012.674512] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
INTRODUCTION Fluoroquinolones (FQs) exist as charged molecules in blood and urine making their absorption, distribution, and elimination likely to be influenced by active transport mechanisms. Greater understanding of in vivo FQ clearance mechanisms should help improve the predictability of drug-drug interactions, enhance the clinical safety and efficacy, and aid future novel drug design strategies. AREAS COVERED The authors present an overview of FQ development and associated drug-drug interactions, followed by systematic quantitative review of the physicochemical and in vivo pharmacokinetic properties for 15 representative FQs using historical clinical literature. These results were correlated with in vitro studies implicating drug transporters in FQ clearance to link clinical and in vitro evidence supporting the contribution of drug transport mechanisms to FQ disposition. Specific transporters likely to handle FQs in human renal proximal tubule cells are also identified. EXPERT OPINION Renal handling, that is, tubular secretion and reabsorption, appears to be the main determinant of FQ plasma half-life, clinical duration of action, and drug-drug interactions. Due to their zwitterionic nature, FQs are likely to interact with organic anion and cation transporters within the solute carrier (SLC) superfamily, including OAT1, OAT3, OCT2, OCTN1, OCTN2, MATE1, and MATE2. The ATP-binding cassette (ABC) transporters MDR1, MRP2, MRP4, and BCRP also may interact with FQs.
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Affiliation(s)
- Aditi Mulgaonkar
- Virginia Commonwealth University, School of Pharmacy, Department of Pharmaceutics, Richmond, VA 23298, USA
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Brincat JP, Broccatelli F, Sabatini S, Frosini M, Neri A, Kaatz GW, Cruciani G, Carosati E. Ligand Promiscuity between the Efflux Pumps Human P-Glycoprotein and S. aureus NorA. ACS Med Chem Lett 2012; 3:248-51. [PMID: 24900460 DOI: 10.1021/ml200293c] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Accepted: 01/23/2012] [Indexed: 01/16/2023] Open
Abstract
Thirty-two diverse compounds were evaluated for their ability to inhibit both Pgp-mediated efflux in mouse T-lymphoma L5178 MDR1 and NorA-mediated efflux in S. aureus SA-1199B. Only four compounds were strong inhibitors of both efflux pumps. Three compounds were found to inhibit Pgp exclusively and strongly, while seven compounds inhibited only NorA. These results demonstrate that Pgp and NorA inhibitors do not necessarily overlap, opening the way to safer therapeutic use of effective NorA inhibitors.
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Affiliation(s)
| | | | | | - Maria Frosini
- Department of Neuroscience, Pharmacology
Unit, University of Siena, Siena, Italy
| | - Annalisa Neri
- Department of Neuroscience, Pharmacology
Unit, University of Siena, Siena, Italy
| | - Glenn W. Kaatz
- Department of Internal Medicine,
Division of Infectious Diseases, School of Medicine, Wayne State University and the John D. Dingell Department of Veterans Affairs Medical Center, Detroit, Michigan 48201, United
States
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Green BR, Bain LJ. Mrp2 is involved in the efflux and disposition of fosinopril. J Appl Toxicol 2011; 33:458-65. [DOI: 10.1002/jat.1767] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 09/13/2011] [Accepted: 10/04/2011] [Indexed: 11/06/2022]
Affiliation(s)
- Benjamin R. Green
- Environmental Toxicology Graduate Program; Clemson University; 132 Long Hall; Clemson; SC; 29634; USA
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Murakami T, Yumoto R. Role of phosphatidylserine binding in tissue distribution of amine-containing basic compounds. Expert Opin Drug Metab Toxicol 2011; 7:353-64. [DOI: 10.1517/17425255.2011.548805] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Moreau A, Le Vee M, Jouan E, Parmentier Y, Fardel O. Drug transporter expression in human macrophages. Fundam Clin Pharmacol 2011; 25:743-52. [PMID: 21210849 DOI: 10.1111/j.1472-8206.2010.00913.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Macrophages represent major cellular targets of various drugs, especially antibiotics and anti-viral drugs. Factors that may govern intracellular accumulation of drugs in these cells, especially those related to activity of drug transporters, are consequently likely important to consider. The present study was therefore designed to extensively characterize expression of solute carrier (SLC) and ATP-binding cassette (ABC) transporters in primary human macrophages generated from blood monocytes. Using quantitative polymerase chain reaction assays, these cells were found to exhibit very high or high levels of mRNA expression of concentrative nucleoside transporter (CNT) 3, equilibrative nucleoside transporter 3, monocarboxylate transporter (MCT) 1, MCT4, peptide/histidine transporter (PHT) 1, PHT2, organic anion transporting polypeptide transporter 2B1 and ABC pumps multidrug resistance protein (MRP) 1/ABCC1 and MRP3/ABCC3. By contrast, other transporters, including the efflux pump ABCB1/P-glycoprotein, were found at lower levels or were not expressed. Concomitantly, human macrophages displayed notable uptake of the MCT substrate lactate and of the CNT substrate uridine and also exhibited cellular efflux of the MRP substrate carboxy-2',7'-dichlorofluorescein. Such a functional expression of these transporters has likely to be considered with respect to cellular pharmacokinetics of drugs targeting macrophages.
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Affiliation(s)
- Amélie Moreau
- EA 4427 Signalisation et Réponse aux Agents Infectieux et Chimiques, Institut de Recherches en Santé, Environnement et Travail, Université de Rennes 1, 2 avenue du Pr Léon Bernard, 35043 Rennes, France
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15
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REAL R, EGIDO E, PÉREZ M, GONZÁLEZ-LOBATO L, BARRERA B, PRIETO JG, ÁLVAREZ AI, MERINO G. Involvement of breast cancer resistance protein (BCRP/ABCG2) in the secretion of danofloxacin into milk: interaction with ivermectin. J Vet Pharmacol Ther 2010; 34:313-21. [DOI: 10.1111/j.1365-2885.2010.01241.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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16
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SIVILS JEFFREYC, GONZALEZ IVEN, BAIN LISAJ. Mice lacking Mrp1 have reduced testicular steroid hormone levels and alterations in steroid biosynthetic enzymes. Gen Comp Endocrinol 2010; 167:51-9. [PMID: 20178799 PMCID: PMC2862834 DOI: 10.1016/j.ygcen.2010.02.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Revised: 02/18/2010] [Accepted: 02/19/2010] [Indexed: 10/19/2022]
Abstract
The multidrug resistance-associated protein 1 (MRP1/ABCC1) is a member of the ABC active transporter family that can transport several steroid hormone conjugates, including 17beta-estradiol glucuronide, dehydroepiandrosterone sulfate (DHEAS), and estrone 3-sulfate. The present study investigated the role that MRP1 plays in maintaining proper hormone levels in the serum and testes. Serum and testicular steroid hormone levels were examined in both wild-type mice and Mrp1 null mice. Serum testosterone levels were reduced 5-fold in mice lacking Mrp1, while testicular androstenedione, testosterone, estradiol, and dehydroepiandrosterone (DHEA) were significantly reduced by 1.7- to 4.5-fold in Mrp1 knockout mice. Investigating the mechanisms responsible for the reduction in steroid hormones in Mrp1-/- mice revealed no differences in the expression or activity of enzymes that inactivate steroids, the sulfotransferases or glucuronosyltransferases. However, steroid biosynthetic enzyme levels in the testes were altered. Cyp17 protein levels were increased by 1.6-fold, while Cyp17 activity using progesterone as a substrate was also increased by 1.4- to 2.0-fold in mice lacking Mrp1. Additionally, the ratio of 17beta-hydroxysteroid dehydrogenase to 3beta-hydroxysteroid dehydrogenase, and steroidogenic factor 1 to 3beta-hydroxysteroid dehydrogenase were significantly increased in the testes of Mrp1-/- mice. These results indicate that Mrp1-/- mice have lowered steroid hormones levels, and suggests that upregulation of steroid biosynthetic enzymes may be an attempt to maintain proper steroid hormone homeostasis.
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Affiliation(s)
- JEFFREY C. SIVILS
- Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, USA
| | - IVEN GONZALEZ
- Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, USA
| | - LISA J. BAIN
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA
- Address correspondence to: Lisa Bain, Clemson University, 132 Long Hall, Clemson, SC 29634. Phone: 1-864-656-5050; FAX: 1-864- 656-0435;
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Pang KS, Maeng HJ, Fan J. Interplay of transporters and enzymes in drug and metabolite processing. Mol Pharm 2010; 6:1734-55. [PMID: 19891494 DOI: 10.1021/mp900258z] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
This review highlights the "interplay" between enzymes and transporters, essential components of eliminating organs for drug removal. The understanding of the interplay is important in terms of deciphering the change of one eliminatory pathway on compensatory mechanisms in drug disposal, and, ultimately, their importance in drug-drug interactions. Controversy existed on the explanation underlying the interplay between transporters and enzymes in the Caco-2 cell monolayer or cell culture systems, but less so on eliminating organs such as the intestine and liver. For the Caco-2 system, the increase in the mean residence time (MRT) accompanying increased secretion had been construed as the basis for increased metabolism. We hold the opposite view and assert that increased secretion should evoke a decrease in metabolism due to the competition between the enzyme and apical efflux transporter for the drug within the cell. To illustrate this point, simulations on the MRT, fraction of dose metabolized (f(met)) and the extraction ratio (ER) as defined by various investigators under linear and nonlinear metabolic conditions were compared to observed data and the trends upon induction/inhibition of secretion. The conclusion is that the f(met) is the more appropriate index to reflect the extent of metabolism in transporter-enzyme interplay, since the parameter captures drug metabolism in the cell when its contents in the apical, cell, and basolateral compartments or the entire dose is considered to be available for metabolism. This parameter for metabolism (f(met)) bears a reciprocal relationship to the secretory intrinsic clearance and is in concordance with the notion that both the enzyme and apical transporter compete for the cellular substrate within. For the liver and intestine, several physiologically based pharmacokinetic (PBPK) models that contain transporters and enzymes were utilized, together with the solved equations for the area under the curve (AUC), metabolic, excretory, and total clearance (CL) to shed meaningful insight of how the inhibition of one pathway can result in a higher AUC and therefore a reduced total clearance for drug, but a higher apparent clearance of the alternate pathway; induction of the same pathway would lead to an increased total clearance but decreased drug AUC, and reduced clearance of the alternate pathway. The use of an increased MRT to explain increased extents of metabolism upon increased apical excretion is not tenable in these organs or "open systems" since the MRT of drug in the cell is reduced with irreversible loss from biliary excretion or hastened gastrointestinal transit of the secreted drug in the lumen. Data in the literature for the Caco-2 system, knockout animals and organ perfusion systems were discussed in relation to these concepts on clearance based on fundamental, pharmacokinetic theory. The shortcomings in data interpretation were discussed. The general conclusion is that a reciprocal relationship exists between the clearances related to enzymes and apical transporters due to their competition for the substrate within the cell, and is a relationship independent of the MRT of drug in the system.
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Affiliation(s)
- K Sandy Pang
- Leslie L. Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada.
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Kato S, Kato Y, Nakamura T, Sugiura T, Kubo Y, Deguchi Y, Tsuji A. Genetic deficiency of carnitine/organic cation transporter 2 (slc22a5) is associated with altered tissue distribution of its substrate pyrilamine in mice. Biopharm Drug Dispos 2010; 30:495-507. [PMID: 19821448 DOI: 10.1002/bdd.681] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Carnitine/organic cation transporter 2 (OCTN2) recognizes various cationic compounds as substrates in vitro, but information on its pharmacokinetic role in vivo is quite limited. This paper demonstrates altered tissue distribution of the OCTN2 substrate pyrilamine in juvenile visceral steatosis (jvs) mice, which have a hereditary defect of the octn2 gene. At 30 min after intravenous injection of pyrilamine, the tissue-to-plasma concentration ratio (K(p)) in the heart and pancreas was higher, whereas the K(p) in kidney and testis was lower in jvs mice compared with wild-type mice. Pyrilamine transport studies in isolated heart slices confirmed higher accumulation, together with lower efflux, of pyrilamine in the heart of jvs mice. The higher accumulation in heart slices of jvs mice was abolished by lowering the temperature, by increasing the substrate concentration, and in the presence of other H(1) antagonists or another OCTN2 substrate, carnitine, suggesting that OCTN2 extrudes pyrilamine from heart tissue. On the other hand, the lower distribution to the kidney of jvs mice was probably due to down-regulation of a basolateral transporter coupled with OCTN2, because, in jvs mice, (i) the K(p) of pyrilamine in kidney assessed immediately after intravenous injection (approximately 1 min) was also lower, (ii) the urinary excretion of pyrilamine was lower, and (iii) the uptake of pyrilamine in kidney slices was lower. The renal uptake of pyrilamine was saturable (K(m) approximately 236 microM) and was strongly inhibited by cyproheptadine, astemizole, ebastine and terfenadine. The present study thus indicates that genetic deficiency of octn2 alters pyrilamine disposition tissue-dependently.
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Affiliation(s)
- Sayaka Kato
- Division of Pharmaceutical Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan
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19
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Abstract
The constituents of the blood-brain barrier, including its efflux transporter system, can efficiently limit brain penetration of potential CNS therapeutics. Effective extrusion from the brain by transporters is a frequent reason for the pharmaceutical industry to exclude novel compounds from further development for CNS therapeutics. Moreover, high transporter expression levels that are present in individual patients or may be generally associated with the pathophysiology seem to be a major cause of therapeutic failure in a variety of CNS diseases including brain tumors, epilepsy, brain HIV infection, and psychiatric disorders. Increasing knowledge of the structure and function of the blood-brain barrier creates a basis for the development of strategies which aim to enhance brain uptake of beneficial pharmaceutical compounds. The different strategies discussed in this review aim to modulate blood-brain barrier function or to bypass constituents of the blood-brain barrier.
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20
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Staud F, Ceckova M, Micuda S, Pavek P. Expression and function of p-glycoprotein in normal tissues: effect on pharmacokinetics. Methods Mol Biol 2010; 596:199-222. [PMID: 19949926 DOI: 10.1007/978-1-60761-416-6_10] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
ATP-binding cassette (ABC) drug efflux transporters limit intracellular concentration of their substrates by pumping them out of cell through an active, energy dependent mechanism. Several of these proteins have been originally associated with the phenomenon of multidrug resistance; however, later on, they have also been shown to control body disposition of their substrates. P-glycoprotein (Pgp) is the first detected and the best characterized of ABC drug efflux transporters. Apart from tumor cells, its constitutive expression has been reported in a variety of other tissues, such as the intestine, brain, liver, placenta, kidney, and others. Being located on the apical site of the plasma membrane, Pgp can remove a variety of structurally unrelated compounds, including clinically relevant drugs, their metabolites, and conjugates from cells. Driven by energy from ATP, it affects many pharmacokinetic events such as intestinal absorption, brain penetration, transplacental passage, and hepatobiliary excretion of drugs and their metabolites. It is widely believed that Pgp, together with other ABC drug efflux transporters, plays a crucial role in the host detoxication and protection against xenobiotic substances. On the other hand, the presence of these transporters in normal tissues may prevent pharmacotherapeutic agents from reaching their site of action, thus limiting their therapeutic potential. This chapter focuses on P-glycoprotein, its expression, localization, and function in nontumor tissues and the pharmacological consequences hereof.
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Affiliation(s)
- Frantisek Staud
- Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University in Prague, Hradec Kralove, Czech Republic.
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21
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Aoki M, Iguchi M, Hayashi H, Shibasaki S, Kurosawa T, Hayashi M. Active uptake of ulifloxacin from plasma to lung that controls its concentration in epithelial lining fluid. Biol Pharm Bull 2009; 32:1095-100. [PMID: 19483322 DOI: 10.1248/bpb.32.1095] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ulifloxacin is a new quinolone antibiotic and it is effective against pneumonia. We previously showed that it is highly distributed into the epithelial lining fluid (ELF) in rats, which might be resulting from certain active transport. The transport system has not been, however, clarified yet. In this study, we attempted to characterize the distribution mechanism of ulifloxacin into the rat ELF. We also aimed to elucidate the feature of ulifloxacin uptake in rat lung and human lung adenocarcinoma cells (Calu-3). In infusion studies, ulifloxacin concentrations in the ELF and lung were higher than that in the plasma, and decreased by co-administration of sparfloxacin or azithromycin to the level of plasma concentration. Integration plot analysis showed that active uptake of ulifloxacin from the plasma to lung was also inhibited by sparfloxacin and azithromycin. In in vitro studies, time and temperature-dependent uptake into Calu-3 was observed, and this uptake was inhibited by sparfloxacin and azithromycin as observed in the rat lung. Additionally sparfloxacin inhibited the active uptake of ulifloxacin into Calu-3 more strongly than levofloxacin as observed in the rat lung. These results suggest that active uptake of ulifloxacin from the plasma to lung controls the distribution of ulifloxacin from the plasma to ELF, and that the uptake of ulifloxacin into Calu-3 has partly similar characteristics to its uptake into the rat lung. We believe our study will contribute to much better understanding of antibiotic efficacy against pathogens which cause pneumonia.
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Affiliation(s)
- Makoto Aoki
- Applied Pharmacology Research Laboratories, Pharmaceutical Research Center, Meiji Seika Kaisha Ltd, Yokohama, Japan.
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22
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Li Y, Liu L, Li J, Xie L, Wang GJ, Liu XD. Transport of gatifloxacin involves Na+/Ca2+ exchange and excludes P-glycoprotein and multidrug resistance associated-proteins in primary cultured rat brain endothelial cells. Eur J Pharmacol 2009; 616:68-72. [PMID: 19497321 DOI: 10.1016/j.ejphar.2009.05.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2008] [Revised: 05/14/2009] [Accepted: 05/19/2009] [Indexed: 11/28/2022]
Abstract
The characteristics of gatifloxacin transport across blood brain barrier were investigated using primary cultured rat brain microvessel endothelial cells (rBMECs) as an in vitro model. Gatifloxacin uptake by rBMECs was time-, temperature- and energy-dependent. Gatifloxacin uptake by rBMECs was not influenced by P-glycoprotein (P-GP) inhibitor cyclosporine A or multidrug resistance associated-proteins (MRPs) inhibitor probenecid. However, verapamil inhibited the uptake in a concentration-dependent manner. Transendothelial transport study showed that transport of gatifloxacin across rBMEC monolayer was bidirectional, verapamil concentration-dependently inhibited transport from the apical to basolateral side, but did not significantly affect transport from basolateral to apical side. Gatifloxacin uptake was decreased in Ca(2+)-deprived medium but increased in Mg(2+)-deprived medium significantly. Furthermore, organic Ca(2+) channel blockers nifedipine and diltiazem had no effect on gatifloxacin uptake, but inorganic Ca(2+) channel blockers Ni(2+) and Mg(2+) inhibited the gatifloxacin uptake. The present study suggests that gatifloxacin transport across rBMECs involves a Na(+)/Ca(2+) exchange mechanism and extracellular Ca(2+) but not P-GP and MRPs.
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Affiliation(s)
- Yang Li
- Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing, Jiangsu, PR China
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23
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Stanley LA, Horsburgh BC, Ross J, Scheer N, Wolf CR. Drug transporters: Gatekeepers controlling access of xenobiotics to the cellular interior. Drug Metab Rev 2009; 41:27-65. [DOI: 10.1080/03602530802605040] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Alvarez AI, Pérez M, Prieto JG, Molina AJ, Real R, Merino G. Fluoroquinolone efflux mediated by ABC transporters. J Pharm Sci 2008; 97:3483-93. [PMID: 18200507 DOI: 10.1002/jps.21233] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Quinolones and fluoroquinolones are broad spectrum bactericidal drugs, which are widely used in both human and veterinary medicine. These drugs can quite easily enter cells and are often used to treat intracellular pathogens. Some fluoroquinolones have been reported to undergo efflux, which could explain their low bioavailability. There is a growing need to understand resistance mechanisms to quinolones, involving for instance mutations or the action of efflux pumps. Several members of the ATP-binding cassette (ABC) drug efflux transporter family (MDR, MRP, ABCG2) significantly affect the pharmacokinetic disposition of quinolones. Active secretory mechanisms common to all fluoroquinolones have been suggested, as well as competition between fluoroquinolones at transporter sites. For grepafloxacin and its metabolites, MRP2 has been demonstrated to mediate biliary excretion. However, MDR1 is responsible for grepafloxacin intestinal secretion. Recently it has been shown that ciprofloxacin and enrofloxacin are efficiently transported ABCG2 substrates which are actively secreted into milk. It appears that multiple ABC transporters contribute to the overall secretion of fluoroquinolones. The objective of this work is to review the recent advances in insights into ABC transporters and their effects on fluoroquinolone disposition and resistance including data on drug secretion into milk.
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Affiliation(s)
- Ana I Alvarez
- Department of Biomedical Sciences, Physiology, University of Leon, Campus de Vegazana s/n, 24071 Leon, Spain.
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25
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HARITOVA AM, SCHRICKX J, LASHEV LD, FINK-GREMMELS J. Expression of MDR1, MRP2 and BCRP mRNA in tissues of turkeys. J Vet Pharmacol Ther 2008; 31:378-85. [DOI: 10.1111/j.1365-2885.2008.00968.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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26
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Hartmann A, Krebber R, Daube G, Hartmann K. Pharmacokinetics of pradofloxacin and doxycycline in serum, saliva, and tear fluid of cats after oral administration. J Vet Pharmacol Ther 2008; 31:87-94. [PMID: 18307499 DOI: 10.1111/j.1365-2885.2007.00932.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The pharmacokinetic properties of pradofloxacin and doxycycline were investigated in serum, saliva, and tear fluid of cats. In a crossover study design, six cats were treated orally with a single dose of pradofloxacin (Veraflox Oral Suspension 2.5%) and doxycycline (Ronaxan 100 mg) at 5 mg/kg body weight. Following administration, samples of serum, saliva, and tear fluid were taken in regular intervals over a period of 24 h and analysed by turbulent flow chromatography/tandem mass spectrometry. All values are given as mean +/- SD. Pradofloxacin reached a mean maximum serum concentration (C(max)) of 1.1 +/- 0.5 microg/mL after 1.8 +/- 1.3 h (t(max)). In saliva and tear fluid, mean C(max) was 6.3 +/- 7.0 and 13.4 +/- 20.9 microg/mL, respectively, and mean t(max) was 0.5 +/- 0 and 0.8 +/- 0.3 h, respectively. Doxycycline reached a mean C(max) in serum of 4.0 +/- 0.8 microg/mL after 4.3 +/- 3.2 h. Whilst only at two time-points doxycycline concentrations close to the limit of quantification were determined in tear fluid, no detectable levels were found in saliva. The high concentrations of pradofloxacin in saliva and tear fluid are promising to apply pradofloxacin for the treatment of conjunctivitis and upper respiratory tract infections in cats. As doxycycline is barely secreted into these fluids after oral application the mechanisms of its clinical efficacy remain unclear.
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Affiliation(s)
- A Hartmann
- Medizinische Kleintierklinik, Ludwig Maximilians University, Munich, Germany.
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27
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Enokizono J, Kusuhara H, Ose A, Schinkel AH, Sugiyama Y. Quantitative investigation of the role of breast cancer resistance protein (Bcrp/Abcg2) in limiting brain and testis penetration of xenobiotic compounds. Drug Metab Dispos 2008; 36:995-1002. [PMID: 18322075 DOI: 10.1124/dmd.107.019257] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The role of breast cancer resistance protein (BCRP/ABCG2) in limiting the brain and testis penetration of xenobiotic compounds in the blood-brain and -testis barriers was investigated using Bcrp(-/-) mice. Tissue/plasma concentration ratios in the brain (K(p,brain)) and testis (K(p,testis)) obtained under steady-state conditions were significantly increased in Bcrp(-/-) mice for PhIP (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine), N-hydroxyl PhIP, MeIQx (2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline), dantrolene, and prazosin. In addition, the K(p,brain) of triamterene and the K(p,testis) of 4'-hydroxyl PhIP were also significantly increased in Bcrp(-/-) mice. The effect of functional impairment of Bcrp on the brain uptake of PhIP, dantrolene, and daidzein in Bcrp(-/-) mice determined using in situ brain perfusion was weaker than that observed on the K(p) values. In vitro transcellular transport experiments using cell lines expressing mouse Bcrp or P-glycoprotein (Mdr1a/Abcb1a) showed that, among the tested Bcrp substrates, PhIP, MeIQx, prazosin, and triamterene are common substrates of Bcrp and P-glycoprotein. The K(p) values of common substrates exhibited a smaller increase both in the brain and testis of Bcrp(-/-) mice than expected from the in vitro Bcrp activities. The Bcrp-specific substrates were weak acids, whereas basic or neutral BCRP substrates were also P-glycoprotein substrates. These results suggest that BCRP limits the tissue penetration of xenobiotic compounds in the blood-brain and -testis barriers, but its in vivo importance is also modulated by P-glycoprotein activity.
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Affiliation(s)
- Junichi Enokizono
- Graduate School of Pharmaceutical Sciences, University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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28
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Aoki M, Iguchi M, Hayashi H, Suzuki H, Shibasaki S, Kurosawa T, Hayashi M. Proposal of Membrane Transport Mechanism of Protein-Unbound Ulifloxacin into Epithelial Lining Fluid Determined by Improved Microdialysis. Biol Pharm Bull 2008; 31:1773-7. [DOI: 10.1248/bpb.31.1773] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Makoto Aoki
- Applied Pharmacology Research Laboratories, Pharmaceutical Research Center, Meiji Seika Kaisha, Ltd
| | - Maki Iguchi
- Applied Pharmacology Research Laboratories, Pharmaceutical Research Center, Meiji Seika Kaisha, Ltd
| | - Hiroyuki Hayashi
- Applied Pharmacology Research Laboratories, Pharmaceutical Research Center, Meiji Seika Kaisha, Ltd
| | - Hisashi Suzuki
- Applied Pharmacology Research Laboratories, Pharmaceutical Research Center, Meiji Seika Kaisha, Ltd
| | - Shigeki Shibasaki
- Applied Pharmacology Research Laboratories, Pharmaceutical Research Center, Meiji Seika Kaisha, Ltd
| | - Tohru Kurosawa
- Applied Pharmacology Research Laboratories, Pharmaceutical Research Center, Meiji Seika Kaisha, Ltd
| | - Masahiro Hayashi
- School of Pharmacy, Tokyo University of Pharmacy and Life Sciences
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29
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Ando T, Kusuhara H, Merino G, Alvarez AI, Schinkel AH, Sugiyama Y. Involvement of Breast Cancer Resistance Protein (ABCG2) in the Biliary Excretion Mechanism of Fluoroquinolones. Drug Metab Dispos 2007; 35:1873-9. [PMID: 17639028 DOI: 10.1124/dmd.107.014969] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Fluoroquinolones are effective antibiotics for the treatment of bile duct infections. It has been shown that the biliary excretion of grepafloxacin is partly accounted for by multidrug resistance-associated protein 2 (MRP2/ABCC2), whereas neither MRP2 nor P-glycoprotein is involved in the biliary excretion of ulifloxacin. In the present study, we examined the involvement of breast cancer resistance protein (BCRP/ABCG2) in the biliary excretion of fluoroquinolones (grepafloxacin, ulifloxacin, ciprofloxacin, and ofloxacin). In Madin-Darby canine kidney II cells expressing human BCRP or mouse Bcrp, the basal-to-apical transport of grepafloxacin and ulifloxacin was greater than that of the mock control, which was inhibited by a BCRP inhibitor, 3-(6-isobutyl-9-methoxy-1,4-dioxo-1,2,3,4,6,7,12,12a-octahydropyrazino[1',2':1,6]pyrido[3,4-b]indol-3-yl)-propionic acid tert-butyl ester (Ko143). Plasma and bile concentrations of fluoroquinolones were determined in wild-type and Bcrp(-/-) mice after i.v. bolus injection. The cumulative biliary excretion of fluoroquinolones was significantly reduced in Bcrp(-/-) mice, resulting in a reduction of the biliary excretion clearances to 86, 50, 40, and 16 of the control values, for ciprofloxacin, grepafloxacin, ofloxacin, and ulifloxacin, respectively. Preinfusion of sulfobromophthalein significantly inhibited the biliary excretion of grepafloxacin in Bcrp(-/-) mice. There was no change in the tissue/plasma concentration ratios of fluoroquinolones in the liver or brain, whereas those in the kidney were increased 3.6- and 1.5-fold for ciprofloxacin and grepafloxacin, respectively, in Bcrp(-/-) mice but were unchanged for ofloxacin and ulifloxacin. The present study shows that BCRP mediates the biliary excretion of fluoroquinolones and suggests that it is also involved in the tubular secretion of ciprofloxacin and grepafloxacin.
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Affiliation(s)
- Tomohiro Ando
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
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Maeda T, Takahashi K, Ohtsu N, Oguma T, Ohnishi T, Atsumi R, Tamai I. Identification of influx transporter for the quinolone antibacterial agent levofloxacin. Mol Pharm 2007; 4:85-94. [PMID: 17274666 DOI: 10.1021/mp060082j] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Quinolone antibacterial agents exhibit high intestinal absorption, selective tissue distribution, and renal and biliary excretion. Several ATP-binding cassette transporters are involved in efflux transport of these agents, but no influx transporters have yet been molecularly identified. In the present study, we aimed to identify the influx transporter(s) of quinolone antibiotics using levofloxacin as a model compound. Several candidate transporter genes were selected based on differential expression of mRNAs among Caco-2 cell subclones that exhibited differential uptake activities for levofloxacin. Based on a functional analysis of each transporter gene for which a good correlation was found between expression level and levofloxacin transport activity in the Caco-2 subclones, organic anion transporting polypeptide 1A2 (OATP1A2 (OATP-A), SLCO1A2) was concluded to transport levofloxacin. When OATP1A2 was expressed in Xenopus oocytes, levofloxacin transport was essentially pH-independent and was not stereoselective. OATP1A2-mediated uptake of levofloxacin showed a K(m) value of 136 microM. Apparent uptake of levofloxacin by Caco-2 cells showed high- and low-affinity components with K(m) values of 0.489 and 14.6 mM, respectively. Accordingly, plural transporters are functional for the transport of levofloxacin in Caco-2 cells, and OATP1A2 is likely to function as a high-affinity transporter. The inhibitory effects and the expression of transport activity of other quinolone antibacterial agents suggested that OATP1A2 commonly transports all the agents tested. In conclusion, this is the first identification of an influx transporter for fluoroquinolones, and the results suggest that active influx transport at least partially explains the high membrane permeability of the quinolone agents in various tissues.
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31
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Haritova AM, Schrickx JA, Fink-Gremmels J. Functional studies on the activity of efflux transporters in an ex vivo model with chicken splenocytes and evaluation of selected fluoroquinolones in this model. Biochem Pharmacol 2007; 73:752-9. [PMID: 17188652 DOI: 10.1016/j.bcp.2006.11.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2006] [Revised: 11/10/2006] [Accepted: 11/16/2006] [Indexed: 10/23/2022]
Abstract
The efflux proteins P-glycoprotein (P-gp), BCRP and members of the MRP-family (MRPs) are increasingly recognized as determinants of the absorption, tissue distribution and excretion of numerous drugs. A widely applied in vitro screening method, to assess the effect of these efflux transporters in transmembrane transport of drugs is based on the use of peripheral blood mononuclear cells (PBMC), in which the efflux of fluorescent dye Rhodamine 123 (Rh-123) can be easily measured. In avian species, the isolation of PBMCs is compromised by the presence of thrombocytes having approximately the same size. As an alternative, we validated the use of isolated splenocytes to assess Rhodamine 123 transport in the presence and absence of specific inhibitors for P-gp, MRPs and BCRP. Rh-123 efflux was concentration-dependent with the percentage of efflux that decreased with increasing concentrations. P-gp inhibitors, PSC833 and GF120918, significantly inhibit Rh-123 efflux, whereas inhibitors for MRPs and BCRP, MK571 and Ko-143, respectively, have a limited inhibitory effect. However, the effect of GF120918 was more pronounced as compared to PSC833, suggesting an additional role for BCRP next to P-gp in Rh-123 efflux. Moreover, fluoroquinolones were selected to test the applicability of the described model. None of these fluoroquinolones significantly inhibit P-gp function at concentrations up to 50 microM, with exception of danofloxacin and danofloxacin mesylate that were found to reduce Rh-123 efflux by approximately 15%.
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Affiliation(s)
- Aneliya Milanova Haritova
- Department of Pharmacology, Veterinary Physiology and Physiological Chemistry, Faculty of Veterinary Medicine, Trakia University, 6000 Stara Zagora, Bulgaria
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32
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Kneuer C, Honscha W, Gäbel G, Honscha KU. Adaptive response to increased bile acids: induction of MDR1 gene expression and P-glycoprotein activity in renal epithelial cells. Pflugers Arch 2007; 454:587-94. [PMID: 17333245 DOI: 10.1007/s00424-007-0235-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2006] [Revised: 01/19/2007] [Accepted: 02/12/2007] [Indexed: 11/28/2022]
Abstract
Cholestatic liver disease and increased serum bile acid concentrations are known to trigger various adaptive responses including the induction of hepatic, intestinal and renal bile acid transport proteins, but renal P-glycoprotein (Pgp, multidrug resistance protein 1, MDR1) remained uninvestigated in this context. We show that treatment of Madin Darby canine kidney (MDCK) cells with pathophysiologically relevant concentrations of chenodeoxycholic acid (CDCA; 100 microM) for 12 h induces MDR1 transcript levels in vitro more than twofold. CDCA and deoxycholic acid pre-treatment for 24-96 h (100 microM) also increased Pgp activity measured as rhodamine efflux, while cholic acid and taurocholic acid were not effective in concentrations up to 600 microM. CDCA pre-treatment (100 microM, 72 h) also resulted in a doubling of rhodamine123 secretion across an epithelium-like monolayer grown on Transwell filters and decreased the sensitivity towards the kidney toxic drugs cyclosporine A and paclitaxel. These findings predict physiologically as well as pharmacologically relevant consequences of liver disease for Pgp substrate transport and toxicity in the kidneys.
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Affiliation(s)
- Carsten Kneuer
- Institute of Pharmacology, Pharmacy and Toxicology, University of Leipzig, An den Tierkliniken 15, 04103 Leipzig, Germany.
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Schrickx JA, Fink-Gremmels J. Danofloxacin-mesylate is a substrate for ATP-dependent efflux transporters. Br J Pharmacol 2007; 150:463-9. [PMID: 17211460 PMCID: PMC2189727 DOI: 10.1038/sj.bjp.0706974] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2006] [Revised: 09/28/2006] [Accepted: 10/16/2006] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND AND PURPOSE Next to its broad antimicrobial spectrum, the therapeutic advantages of the fluoroquinolone antimicrobial drug Danofloxacin-Mesylate (DM) are attributed to its rapid distribution to the major target tissues such as lungs, intestines and the mammary gland in animals. Previous analyses revealed that effective drug concentrations are achieved also in luminal compartments of these organs, suggesting that active transport proteins facilitate excretion into the luminal space. Members of the ATP-Binding Cassette (ABC) superfamily, including P-gp, BCRP and MRP2 are known to be expressed in many tissue barriers and in cell-membranes facing luminal compartments. Hence we hypothesized that DM is a substrate for one of these efflux-transporters. EXPERIMENTAL APPROACH Confluent monolayers of Caco-2 cells, grown on microporous membranes in two-chamber devices were used. DM concentrations were measured by fluorimetric assay after HPLC of the culture media. KEY RESULTS DM transport across Caco-2 cells was asymmetric, with a rate of secretion exceeding that of absorption. The P-gp inhibitors PSC833 and GF120918 and the MRP-inhibitor MK571 partially decreased the secretion of DM and increased its absorption rate. The BCRP inhibitor, Ko143, decreased secretion only at a concentration of 1 microM. When DM was applied together with ciprofloxacin, secretion as well as absorption of DM decreased. CONCLUSIONS AND IMPLICATIONS DM is a substrate for the efflux transporters P-gp and MRP2, whereas the specific role of BCRP in DM transport needs further evaluation. These findings provide a mechanistic basis for the understanding of the pharmacokinetics of DM in healthy and diseased individuals.
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Affiliation(s)
- J A Schrickx
- Department of Veterinary Pharmacology, Pharmacy and Toxicology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands.
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Bakos E, Homolya L. Portrait of multifaceted transporter, the multidrug resistance-associated protein 1 (MRP1/ABCC1). Pflugers Arch 2006; 453:621-41. [PMID: 17187268 DOI: 10.1007/s00424-006-0160-8] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2006] [Revised: 05/10/2006] [Accepted: 05/24/2006] [Indexed: 10/23/2022]
Abstract
MRP1 (ABCC1) is a peculiar member of the ABC transporter superfamily for several aspects. This protein has an unusually broad substrate specificity and is capable of transporting not only a wide variety of neutral hydrophobic compounds, like the MDR1/P-glycoprotein, but also facilitating the extrusion of numerous glutathione, glucuronate, and sulfate conjugates. The transport mechanism of MRP1 is also complex; a composite substrate-binding site permits both cooperativity and competition between various substrates. This versatility and the ubiquitous tissue distribution make this transporter suitable for contributing to various physiological functions, including defense against xenobiotics and endogenous toxic metabolites, leukotriene-mediated inflammatory responses, as well as protection from the toxic effect of oxidative stress. In this paper, we give an overview of the considerable amount of knowledge which has accumulated since the discovery of MRP1 in 1992. We place special emphasis on the structural features essential for function, our recent understanding of the transport mechanism, and the numerous assignments of this transporter.
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Affiliation(s)
- Eva Bakos
- Institute of Enzymology, Hungarian Academy of Sciences, Budapest, Hungary
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Couture L, Nash JA, Turgeon J. The ATP-binding cassette transporters and their implication in drug disposition: a special look at the heart. Pharmacol Rev 2006; 58:244-58. [PMID: 16714487 DOI: 10.1124/pr.58.2.7] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The passage of drugs across cell membranes dictates their absorption, distribution, metabolism, and excretion. This process is determined by several factors including the molecular weight of the compounds, their shape, degree of ionization, and binding to proteins. Accumulation of xenobiotics into tissues does not depend only on their ability to enter cells, but also on their ability to leave them. For instance, the role of efflux transporters such as ATP-binding cassette (ABC) proteins in the disposition of drugs is now well recognized. Actually, ABC transporters act in synergy with drug-metabolizing enzymes to protect the organism from toxic compounds. The most studied transporter from the ABC transporter superfamily, P-glycoprotein, was found to be overexpressed in tumor cells and associated with an acquired resistance to several anticancer drugs. P-glycoprotein, thought at first to be confined to tumor cells, was subsequently recognized to be expressed in normal tissues such as the liver, kidney, intestine, and heart. Even though information remains rather limited on the functional role of ABC transporters in the myocardium, it is hypothesized that they may modulate efficacy and toxicity of cardioactive agents. This review addresses recent progress on knowledge about the ABC transporters in drug disposition and more precisely their role in drug distribution to the heart.
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Affiliation(s)
- Lucie Couture
- Faculté de Pharmacie, Université de Montréal, C.P. 6128, Succursale Centre-Ville, Montreal, Quebec, Canada, H3C 3J7
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HARITOVA A, SCHRICKX J, FINK-GREMMELS J. D07 Effect of fluoroquinolones on P-glycoprotein activity in chickens. J Vet Pharmacol Ther 2006. [DOI: 10.1111/j.1365-2885.2006.00762_9.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Gouaze-Andersson V, Cabot MC. Glycosphingolipids and drug resistance. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2006; 1758:2096-103. [PMID: 17010304 DOI: 10.1016/j.bbamem.2006.08.012] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2006] [Revised: 08/23/2006] [Accepted: 08/23/2006] [Indexed: 01/31/2023]
Abstract
Drug resistance, an all too frequent characteristic of cancer, represents a serious barrier to successful treatment. Although many resistance mechanisms have been described, those that involve membrane-resident proteins belonging to the ABC (ATP binding cassette) transporter superfamily are of particular interest. In addition to cancer, the ABC transporter proteins are active in diseases such as malaria and leishmaniasis. A recent renaissance in lipid metabolism, specifically ceramide and sphingolipids, has fueled research and provided insight into the role of glycosphingolipids in multidrug resistance. This article reviews current knowledge on ceramide, glucosylceramide synthase and cerebrosides, and the relationship of these lipids to cellular response to anticancer agents.
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Affiliation(s)
- Valerie Gouaze-Andersson
- Department of Experimental Therapeutics, The John Wayne Cancer Institute at Saint John's Health Center, 2200 Santa Monica Blvd., Santa Monica, CA 90404, USA
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Hirano T, Yasuda S, Osaka Y, Kobayashi M, Itagaki S, Iseki K. Mechanism of the inhibitory effect of zwitterionic drugs (levofloxacin and grepafloxacin) on carnitine transporter (OCTN2) in Caco-2 cells. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2006; 1758:1743-50. [PMID: 16928358 DOI: 10.1016/j.bbamem.2006.07.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2006] [Revised: 06/08/2006] [Accepted: 07/05/2006] [Indexed: 11/25/2022]
Abstract
L-Carnitine plays an important role in lipid metabolism by facilitating the transport of long-chain fatty acids across the mitochondrial inner membrane followed by fatty acid beta-oxidation. It is known that L-carnitine exists as a zwitterion and that member of the OCTN family play an important role in its transport. The aims of this study were to characterize L-carnitine transport in the intestine by using Caco-2 cells and to elucidate the effects of levofloxacin (LVFX) and grepafloxacin (GPFX), which are zwitterionic drugs, on L-carnitine uptake. Kinetic analysis showed that the half-saturation Na+ concentration, Hill coefficient and Km value of L-carnitine uptake in Caco-2 cells were 10.3 +/- 4.5 mM, 1.09 and 8.0 +/- 1.0 microM, respectively, suggesting that OCTN2 mainly transports L-carnitine. LVFX and GPFX have two pKa values and the existence ratio of their zwitterionic forms is higher under a neutral condition than under an acidic condition. Experiments on the inhibitory effect of LVFX and GPFX on L-carnitine uptake showed that LVFX and GPFX inhibited L-carnitine uptake more strongly at pH 7.4 than at pH 5.5. It was concluded that the zwitterionic form of drugs plays an important role in inhibition of OCTN2 function.
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Affiliation(s)
- Takeshi Hirano
- Department of Clinical Pharmaceutics and Therapeutics, Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-12-jo, Nishi-6-chome, Kita-ku, Sapporo 060-0812, Japan
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Conseil G, Deeley RG, Cole SPC. Polymorphisms of MRP1 (ABCC1) and related ATP-dependent drug transporters. Pharmacogenet Genomics 2006; 15:523-33. [PMID: 16006996 DOI: 10.1097/01.fpc.0000167333.38528.ec] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Genetic variations in drug metabolizing enzymes and targets are established determinants of adverse drug reactions and interactions, but less is known about the role of genetic polymorphisms in membrane transport proteins. MRP1 (ABCC1) is one of 13 polytopic membrane proteins that comprise the 'C' subfamily of the ATP-binding cassette (ABC) superfamily of transport proteins. MRP1 and related ABCC family members, including MRP2, 3, 4 and 5 (ABCC2, 3, 4 and 5), each have a distinctive pattern of tissue expression and substrate specificity. Together, these five transporters play important roles in the disposition and elimination of drugs and other organic anions, and in maintenance of blood-tissue barriers, as confirmed by enhanced chemosensitivity of respective knockout mice. Moreover, Mrp2 (Abcc2) deficient animals display mild conjugated hyperbilirubinemia, corresponding to a human condition known as Dubin-Johnson syndrome (DJS). Naturally occurring mutations in MRP/ABCC-related drug transporters have been reported, some of which are non-synonymous single nucleotide polymorphisms. The consequences of the resulting amino acid changes can sometimes be predicted from in vitro site-directed mutagenesis studies or from knowledge of mutations of analogous (conserved) residues in ABCC proteins that cause DJS, Pseudoxanthoma elasticum (ABCC6), cystic fibrosis (CFTR/ABCC7) or persistent hyperinsulinemic hypoglycemia of infancy (SUR1/ABCC8). Continual updating of databases of sequence variants and haplotype analysis, together with in vitro biochemical validation assays and pharmacological studies in knockout animals, should make it possible to determine how genetic variation in the MRP-related transporters contributes to the range of responses to drugs and chemicals observed in different human populations.
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Affiliation(s)
- Gwenaëlle Conseil
- Cancer Research Laboratories, Queen's University, Kingston, Ontario, Canada
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Abstract
Quinolones are one of the largest classes of antimicrobial agents used worldwide. This review considers the quinolones that are available currently and used widely in Europe (norfoxacin, ciprofloxacin, ofloxacin, levofloxacin and moxifloxacin) within their historical perspective, while trying to position them in the context of recent and possible future advances based on an understanding of: (1) their chemical structures and how these impact on activity and toxicity; (2) resistance mechanisms (mutations in target genes, efflux pumps); (3) their pharmacodynamic properties (AUC/MIC and Cmax/MIC ratios; mutant prevention concentration and mutant selection window); and (4) epidemiological considerations (risk of emergence of resistance, clonal spread). Their main indications are examined in relation to their advantages and drawbacks. Overall, it is concluded that these important agents should be used in an educated fashion, based on a careful balance between their ease of use and efficacy vs. the risk of emerging resistance and toxicity. However, there is now substantial evidence to support use of the most potent drug at the appropriate dose whenever this is required.
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Affiliation(s)
- F Van Bambeke
- Unit of Cellular and Molecular Pharmacology, Catholic University of Louvain, Brussels.
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Li Q, Kato Y, Sai Y, Imai T, Tsuji A. Multidrug Resistance—Associated Protein 1 Functions as an Efflux Pump of Xenobiotics in the Skin. Pharm Res 2005; 22:842-6. [PMID: 15948026 DOI: 10.1007/s11095-005-4576-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2004] [Accepted: 02/23/2005] [Indexed: 10/25/2022]
Abstract
PURPOSE Recent research has identified gene expression of several types of xenobiotic transporters in the skin. The aim of this study was to investigate whether multidrug resistance-associated protein 1 (MRP1) functions in the skin. METHODS The distribution of [14C]grepafloxacin in vivo and the transport of 1-[2-amino-5-(2,7-dichloro-6-hydroxy-3-oxo-9-xanthenyl)phenoxy]-2-(2-amino-5-methylphenoxy)ethane-N,N,N',N'-tetraacetic acid (fluo 3) were examined in the skin of Mrp1 knockout mice [FVB/Mrp1(-/-)] and normal mice [FVB/Mrp1(+/+)]. RESULTS The tissue-to-plasma concentration ratio of [14C]grepafloxacin was higher in the skin of FVB/Mrp1(-/-) mice than that of FVB/Mrp1(+/+) mice. In skin slices of hairless mouse incubated with fluo 3 pentaacetoxymethyl ester, the accumulation of fluo 3 was significantly increased in the presence of probenecid (2 mM) and carbonyl cyanide p-trifluoromethoxyphenylhydrazone (5 muM) in a time-dependent manner but did not change in the presence of tetraethylammonium (2 mM). In FVB/Mrp1(-/-) mouse skin, the accumulation of fluo 3 increased time-dependently, while no increase was observed in FVB/Mrp1(+/+) mouse skin. CONCLUSIONS These findings suggest that Mrp1 is involved in the efflux of [14C]grepafloxacin and fluo 3 in the skin, possibly acting as part of a barrier system against xenobiotic compounds.
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Affiliation(s)
- Qing Li
- Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa, Japan
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Löscher W, Potschka H. Role of drug efflux transporters in the brain for drug disposition and treatment of brain diseases. Prog Neurobiol 2005; 76:22-76. [PMID: 16011870 DOI: 10.1016/j.pneurobio.2005.04.006] [Citation(s) in RCA: 418] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2004] [Revised: 03/23/2005] [Accepted: 04/26/2005] [Indexed: 01/01/2023]
Abstract
The blood-brain barrier (BBB) serves as a protective mechanism for the brain by preventing entry of potentially harmful substances from free access to the central nervous system (CNS). Tight junctions present between the brain microvessel endothelial cells form a diffusion barrier, which selectively excludes most blood-borne substances from entering the brain. Astrocytic end-feet tightly ensheath the vessel wall and appear to be critical for the induction and maintenance of the barrier properties of the brain capillary endothelial cells. Because of these properties, the BBB only allows entry of lipophilic compounds with low molecular weights by passive diffusion. However, many lipophilic drugs show negligible brain uptake. They are substrates for drug efflux transporters such as P-glycoprotein (Pgp), multidrug resistance proteins (MRPs) or organic anion transporting polypeptides (OATPs) that are expressed at brain capillary endothelial cells and/or astrocytic end-feet and are key elements of the molecular machinery that confers the special permeability properties to the BBB. The combined action of these carrier systems results in rapid efflux of xenobiotics from the CNS. The objective of this review is to summarize transporter characteristics (cellular localization, specificity, regulation, and potential inhibition) for drug efflux transport systems identified in the BBB and blood-cerebrospinal fluid (CSF) barrier. A variety of experimental approaches available to ascertain or predict the impact of efflux transport on brain access of therapeutic drugs also are described and critically discussed. The potential impact of efflux transport on the pharmacodynamics of agents acting in the CNS is illustrated. Furthermore, the current knowledge about drug efflux transporters as a major determinant of multidrug resistance of brain diseases such as epilepsy is reviewed. Finally, we summarize strategies for modulating or by-passing drug efflux transporters at the BBB as novel therapeutic approaches to drug-resistant brain diseases.
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Affiliation(s)
- Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Bünteweg 17, D-30559 Hannover, Germany
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