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Thoma G, Markert C, Lueoend R, Miltz W, Spanka C, Bollbuck B, Wolf RM, Srinivas H, Penno CA, Kiffe M, Gajewska M, Bednarczyk D, Wieczorek G, Evans A, Beerli C, Röhn TA. Discovery of Amino Alcohols as Highly Potent, Selective, and Orally Efficacious Inhibitors of Leukotriene A4 Hydrolase. J Med Chem 2023; 66:16410-16425. [PMID: 38015154 DOI: 10.1021/acs.jmedchem.3c01866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
The discovery of chiral amino alcohols derived from our previously disclosed clinical LTA4H inhibitor LYS006 is described. In a biochemical assay, their optical antipodes showed similar potencies, which could be rationalized by the cocrystal structures of these compounds bound to LTA4H. Despite comparable stabilities in liver microsomes, they showed distinct in vivo PK properties. Selective O-phosphorylation of the (R)-enantiomers in blood led to clearance values above the hepatic blood flow, whereas the (S)-enantiomers were unaffected and exhibited satisfactory metabolic stabilities in vivo. Introduction of two pyrazole rings led to compound (S)-2 with a more balanced distribution of polarity across the molecule, exhibiting high selectivity and excellent potency in vitro and in vivo. Furthermore, compound (S)-2 showed favorable profiles in 16-week IND-enabling toxicology studies in dogs and rats. Based on allometric scaling and potency in whole blood, compound (S)-2 has the potential for a low oral efficacious dose administered once daily.
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Affiliation(s)
- Gebhard Thoma
- Global Discovery Chemistry, Biomedical Research, Novartis Pharma AG, 4002 Basel, Switzerland
| | - Christian Markert
- Global Discovery Chemistry, Biomedical Research, Novartis Pharma AG, 4002 Basel, Switzerland
| | - Rainer Lueoend
- Global Discovery Chemistry, Biomedical Research, Novartis Pharma AG, 4002 Basel, Switzerland
| | - Wolfgang Miltz
- Global Discovery Chemistry, Biomedical Research, Novartis Pharma AG, 4002 Basel, Switzerland
| | - Carsten Spanka
- Global Discovery Chemistry, Biomedical Research, Novartis Pharma AG, 4002 Basel, Switzerland
| | - Birgit Bollbuck
- Global Discovery Chemistry, Biomedical Research, Novartis Pharma AG, 4002 Basel, Switzerland
| | - Romain M Wolf
- Global Discovery Chemistry, Biomedical Research, Novartis Pharma AG, 4002 Basel, Switzerland
| | - Honnappa Srinivas
- Chemical Biology & Therapeutics, Biomedical Research, Novartis Pharma AG, 4002 Basel, Switzerland
| | - Carlos A Penno
- Chemical Biology & Therapeutics, Biomedical Research, Novartis Pharma AG, 4002 Basel, Switzerland
| | - Michael Kiffe
- PK Sciences, Biomedical Research, Novartis Pharma AG, 4002 Basel, Switzerland
| | - Monika Gajewska
- PK Sciences, Biomedical Research, Novartis Pharma AG, 4002 Basel, Switzerland
| | - Dallas Bednarczyk
- Discovery & Translational Lab, Biomedical Research, Novartis Pharma AG, 250 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Grazyna Wieczorek
- Immunology Disease Area, Biomedical Research, Novartis Pharma AG, 4002 Basel, Switzerland
| | - Amanda Evans
- Immunology Disease Area, Biomedical Research, Novartis Pharma AG, 4002 Basel, Switzerland
| | - Christian Beerli
- Immunology Disease Area, Biomedical Research, Novartis Pharma AG, 4002 Basel, Switzerland
| | - Till A Röhn
- Immunology Disease Area, Biomedical Research, Novartis Pharma AG, 4002 Basel, Switzerland
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Patel M, Riede J, Bednarczyk D, Poller B, Deshmukh SV. Simplifying the Extended Clearance Concept Classification System (EC3S) to Guide Clearance Prediction in Drug Discovery. Pharm Res 2023; 40:937-949. [PMID: 36859748 DOI: 10.1007/s11095-023-03482-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Accepted: 02/10/2023] [Indexed: 03/03/2023]
Abstract
PURPOSE The Extended Clearance Concept Classification System was established as a development-stage tool to provide a framework for identifying fundamental mechanism(s) governing drug disposition in humans. In the present study, the applicability of the EC3S in drug discovery has been investigated. In its current format, the EC3S relies on low-throughput hepatocyte uptake data, which are not frequently generated in a discovery setting. METHODS A relationship between hepatocyte uptake clearance and MDCK permeability was first established along with intrinsic clearance from human liver microsomes. The performance of this approach was examined by categorizing 64 drugs into EC3S classes and comparing the predicted major elimination pathway(s) to that observed in humans. As an extension of the work, the ability of the simplified EC3S to predict human systemic clearance based on intrinsic clearance generated using in-vitro metabolic systems was evaluated. RESULTS The assessment enabled the use of MDCK permeability and unscaled unbound intrinsic clearance to generate cut-off criteria to categorize compounds into four EC3S classes: Class 12ab, 2cd, 34ab, and 34cd, with major elimination mechanism(s) assigned to each class. The predictivity analysis suggested that systemic clearance could generally be predicted within threefold for EC3S class 12ab and 34ab compounds. For classes 2cd and 34cd, systemic clearance was poorly predicted using in-vitro systems explored in this study. CONCLUSION Collectively, our simplified classification approach is expected to facilitate the identification of mechanism(s) involved in drug elimination, faster resolution of in-vitro to in-vivo disconnects, and better design of mechanistic pharmacokinetic studies in drug discovery.
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Affiliation(s)
- Mitesh Patel
- Pharmacokinetic Sciences, Novartis Institutes for BioMedical Research, Inc., 250 Massachusetts Avenue 2A/242, Cambridge, MA, 02139, USA
| | - Julia Riede
- Pharmacokinetic Sciences, Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Dallas Bednarczyk
- Pharmacokinetic Sciences, Novartis Institutes for BioMedical Research, Inc., 250 Massachusetts Avenue 2A/242, Cambridge, MA, 02139, USA
| | - Birk Poller
- Pharmacokinetic Sciences, Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Sujal V Deshmukh
- Pharmacokinetic Sciences, Novartis Institutes for BioMedical Research, Inc., 250 Massachusetts Avenue 2A/242, Cambridge, MA, 02139, USA.
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Argikar U, Blatter M, Bednarczyk D, Chen Z, Cho YS, Doré M, Dumouchel JL, Ho S, Hoegenauer K, Kawanami T, Mathieu S, Meredith E, Möbitz H, Murphy SK, Parthasarathy S, Soldermann CP, Santos J, Silver S, Skolnik S, Stojanovic A. Paradoxical Increase of Permeability and Lipophilicity with the Increasing Topological Polar Surface Area within a Series of PRMT5 Inhibitors. J Med Chem 2022; 65:12386-12402. [PMID: 36069672 DOI: 10.1021/acs.jmedchem.2c01068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An imidazolone → triazolone replacement addressed the limited passive permeability of a series of protein arginine methyl transferase 5 (PRMT5) inhibitors. This increase in passive permeability was unexpected given the increase in the hydrogen bond acceptor (HBA) count and topological polar surface area (TPSA), two descriptors that are typically inversely correlated with permeability. Quantum mechanics (QM) calculations revealed that this unusual effect was due to an electronically driven disconnect between TPSA and 3D-PSA, which manifests in a reduction in overall HBA strength as indicated by the HBA moment descriptor from COSMO-RS (conductor-like screening model for real solvation). HBA moment was subsequently deployed as a design parameter leading to the discovery of inhibitors with not only improved passive permeability but also reduced P-glycoprotein (P-gp) transport. Our case study suggests that hidden polarity as quantified by TPSA-3DPSA can be rationally designed through QM calculations.
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Affiliation(s)
- Upendra Argikar
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts 02139, United States
| | - Markus Blatter
- Novartis Institutes for BioMedical Research, Basel 4002, Switzerland
| | - Dallas Bednarczyk
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts 02139, United States
| | - Zhuoliang Chen
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts 02139, United States
| | - Young Shin Cho
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts 02139, United States
| | - Michaël Doré
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts 02139, United States
| | - Jennifer L Dumouchel
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts 02139, United States
| | - Samuel Ho
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts 02139, United States
| | | | - Toshio Kawanami
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts 02139, United States
| | - Simon Mathieu
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts 02139, United States
| | - Erik Meredith
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts 02139, United States
| | - Henrik Möbitz
- Novartis Institutes for BioMedical Research, Basel 4002, Switzerland
| | - Stephen K Murphy
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts 02139, United States
| | | | | | - Jobette Santos
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts 02139, United States
| | - Serena Silver
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts 02139, United States
| | - Suzanne Skolnik
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts 02139, United States
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Loryan I, Reichel A, Feng B, Bundgaard C, Shaffer C, Kalvass C, Bednarczyk D, Morrison D, Lesuisse D, Hoppe E, Terstappen GC, Fischer H, Di L, Colclough N, Summerfield S, Buckley ST, Maurer TS, Fridén M. Unbound Brain-to-Plasma Partition Coefficient, K p,uu,brain-a Game Changing Parameter for CNS Drug Discovery and Development. Pharm Res 2022; 39:1321-1341. [PMID: 35411506 PMCID: PMC9246790 DOI: 10.1007/s11095-022-03246-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 03/22/2022] [Indexed: 12/11/2022]
Abstract
PURPOSE More than 15 years have passed since the first description of the unbound brain-to-plasma partition coefficient (Kp,uu,brain) by Prof. Margareta Hammarlund-Udenaes, which was enabled by advancements in experimental methodologies including cerebral microdialysis. Since then, growing knowledge and data continue to support the notion that the unbound (free) concentration of a drug at the site of action, such as the brain, is the driving force for pharmacological responses. Towards this end, Kp,uu,brain is the key parameter to obtain unbound brain concentrations from unbound plasma concentrations. METHODS To understand the importance and impact of the Kp,uu,brain concept in contemporary drug discovery and development, a survey has been conducted amongst major pharmaceutical companies based in Europe and the USA. Here, we present the results from this survey which consisted of 47 questions addressing: 1) Background information of the companies, 2) Implementation, 3) Application areas, 4) Methodology, 5) Impact and 6) Future perspectives. RESULTS AND CONCLUSIONS From the responses, it is clear that the majority of the companies (93%) has established a common understanding across disciplines of the concept and utility of Kp,uu,brain as compared to other parameters related to brain exposure. Adoption of the Kp,uu,brain concept has been mainly driven by individual scientists advocating its application in the various companies rather than by a top-down approach. Remarkably, 79% of all responders describe the portfolio impact of Kp,uu,brain implementation in their companies as 'game-changing'. Although most companies (74%) consider the current toolbox for Kp,uu,brain assessment and its validation satisfactory for drug discovery and early development, areas of improvement and future research to better understand human brain pharmacokinetics/pharmacodynamics translation have been identified.
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Affiliation(s)
- Irena Loryan
- Department of Pharmacy, Uppsala University, Box 580, Uppsala, Sweden.
| | | | - Bo Feng
- DMPK, Vertex Pharmaceuticals, Boston, Massachusetts, 02210, USA
| | | | - Christopher Shaffer
- External Innovation, Research & Development, Biogen Inc., Cambridge, Massachusetts, USA
| | - Cory Kalvass
- DMPK-BA, AbbVie, Inc., North Chicago, Illinois, USA
| | - Dallas Bednarczyk
- Pharmacokinetic Sciences, Novartis Institutes for BioMedical Research, Cambridge, Massachusetts, USA
| | | | | | - Edmund Hoppe
- DMPK, Boehringer-Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
| | | | - Holger Fischer
- Translational PK/PD and Clinical Pharmacology, Pharmaceutical Sciences, Roche Pharma Research & Early Development, Roche Innovation Center Basel, Basel, Switzerland
| | - Li Di
- Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research and Development, Groton, Connecticut, USA
| | | | - Scott Summerfield
- Bioanalysis Immunogenicity and Biomarkers, GSK, Gunnels Wood Road, Stevenage, SG1 2NY, Hertfordshire, UK
| | | | - Tristan S Maurer
- Pharmacokinetics, Dynamics and Metabolism, Pfizer Worldwide Research and Development, Cambridge, Massachusetts, USA
| | - Markus Fridén
- Department of Pharmacy, Uppsala University, Box 580, Uppsala, Sweden
- Inhalation Product Development, Pharmaceutical Technology & Development, Operations, AstraZeneca, Gothenburg, Sweden
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Bednarczyk D. Passive Influx and Ion Trapping Are More Relevant to the Cellular Accumulation of Highly Permeable Low-Molecular-Weight Acidic Drugs than Is Organic Anion Transporter 2. Drug Metab Dispos 2021; 49:648-657. [PMID: 34031139 DOI: 10.1124/dmd.121.000425] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 05/17/2021] [Indexed: 11/22/2022] Open
Abstract
Recently published work suggests that highly permeable low-molecular-weight (LMW) acidic drugs are transported by organic anion transporter 2 (OAT2). However, an asymmetric distribution of ionizable drugs in subcellular organelles where pH gradients are significant may occur in the presence of an inhibitor relative to its absence (e.g., lysosomal trapping). In the present study, OAT2-mediated transport of highly permeable LMW anions could not be demonstrated using OAT2 transfected cells, despite robust transport of the OAT2 substrate penciclovir. Moreover, a rifamycin SV (RifSV)-dependent reduction in the accumulation of highly permeable LMW anions previously observed in hepatocytes could be qualitatively reproduced using HepG2 cells and also in Madin-Darby canine kidney (MDCK) cells, which lack expression of OAT2. Neither HepG2 nor MDCK cells demonstrated meaningful penciclovir transport, nor was the cellular accumulation of the highly permeable LMW anions sensitive to competitive inhibition by the neutral OAT2 substrate penciclovir. Both cell lines, however, demonstrated sensitivity to the mitochondrial uncoupler p-trifluoromethoxy carbonyl cyanide phenyl hydrazone (FCCP) in a manner similar to RifSV. Furthermore, the transepithelial MDCK permeability of the highly permeable LMW anions was measured in the absence and presence of RifSV and FCCP at concentrations that reduced the cellular accumulation of anions. Neither inhibitor, nor the OAT2 inhibitor ketoprofen, reduced the transepithelial flux of the anions as would be anticipated for transported substrate inhibition. The findings presented here are aligned with cellular accumulation of highly permeable LMW anions being significantly determined by ion trapping sensitive to mitochondrial uncoupling, rather than the result of OAT2-mediated transport. SIGNIFICANCE STATEMENT: The manuscript illustrates that passive influx and ion trapping are more relevant to the cellular accumulation of highly permeable low-molecular-weight acidic drugs than is the previously proposed mechanism of OAT2-mediated transport. The outcome illustrated here highlights a rare, and perhaps previously not reported, observation of anionic drug trapping in a compartment sensitive to mitochondrial uncoupling (e.g., the mitochondrial matrix) that may be confused for transporter-mediated uptake.
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Affiliation(s)
- Dallas Bednarczyk
- Novartis Institutes for BioMedical Research, Cambridge, Massachusetts
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6
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Pottel J, Armstrong D, Zou L, Fekete A, Huang XP, Torosyan H, Bednarczyk D, Whitebread S, Bhhatarai B, Liang G, Jin H, Ghaemi SN, Slocum S, Lukacs KV, Irwin JJ, Berg EL, Giacomini KM, Roth BL, Shoichet BK, Urban L. The activities of drug inactive ingredients on biological targets. Science 2020; 369:403-413. [PMID: 32703874 DOI: 10.1126/science.aaz9906] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 05/18/2020] [Indexed: 12/22/2022]
Abstract
Excipients, considered "inactive ingredients," are a major component of formulated drugs and play key roles in their pharmacokinetics. Despite their pervasiveness, whether they are active on any targets has not been systematically explored. We computed the likelihood that approved excipients would bind to molecular targets. Testing in vitro revealed 25 excipient activities, ranging from low-nanomolar to high-micromolar concentration. Another 109 activities were identified by testing against clinical safety targets. In cellular models, five excipients had fingerprints predictive of system-level toxicity. Exposures of seven excipients were investigated, and in certain populations, two of these may reach levels of in vitro target potency, including brain and gut exposure of thimerosal and its major metabolite, which had dopamine D3 receptor dissociation constant K d values of 320 and 210 nM, respectively. Although most excipients deserve their status as inert, many approved excipients may directly modulate physiologically relevant targets.
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Affiliation(s)
- Joshua Pottel
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA
| | - Duncan Armstrong
- Preclinical Safety, Novartis Institutes for Biomedical Research, Cambridge, MA 02139, USA
| | - Ling Zou
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94158, USA
| | - Alexander Fekete
- Preclinical Safety, Novartis Institutes for Biomedical Research, Cambridge, MA 02139, USA
| | - Xi-Ping Huang
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27759, USA
| | - Hayarpi Torosyan
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA
| | - Dallas Bednarczyk
- PK Sciences, Novartis Institutes for Biomedical Research, Cambridge, MA 02139, USA
| | - Steven Whitebread
- Preclinical Safety, Novartis Institutes for Biomedical Research, Cambridge, MA 02139, USA
| | - Barun Bhhatarai
- PK Sciences, Novartis Institutes for Biomedical Research, Cambridge, MA 02139, USA
| | - Guiqing Liang
- PK Sciences, Novartis Institutes for Biomedical Research, Cambridge, MA 02139, USA
| | - Hong Jin
- Preclinical Safety, Novartis Institutes for Biomedical Research, Cambridge, MA 02139, USA
| | - S Nassir Ghaemi
- Translational Medicine, Novartis Institutes for Biomedical Research, Cambridge, MA 02139, USA.,Tufts University School of Medicine, Boston, MA 02111, USA.,Harvard Medical School, Boston, MA 02115, USA
| | - Samuel Slocum
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27759, USA
| | - Katalin V Lukacs
- National Heart and Lung Institute, Imperial College, London SW7 2AZ, UK
| | - John J Irwin
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA
| | - Ellen L Berg
- Eurofins, DiscoverX, South San Francisco, CA 94080, USA
| | - Kathleen M Giacomini
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94158, USA
| | - Bryan L Roth
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27759, USA
| | - Brian K Shoichet
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94158, USA.
| | - Laszlo Urban
- Preclinical Safety, Novartis Institutes for Biomedical Research, Cambridge, MA 02139, USA.
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Bednarczyk D, Sanghvi MV. Organic anion transporting polypeptide 2B1 (OATP2B1), an expanded substrate profile, does it align with OATP2B1’s hypothesized function? Xenobiotica 2020; 50:1128-1137. [DOI: 10.1080/00498254.2020.1745318] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Dallas Bednarczyk
- Pharmacokinetic Sciences, Novartis Institutes of BioMedical Science, Cambridge, MA, USA
| | - Menaka V. Sanghvi
- Pharmacokinetic Sciences, Novartis Institutes of BioMedical Science, Cambridge, MA, USA
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8
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Affiliation(s)
- Dallas Bednarczyk
- Pharmacokinetic Sciences, Novartis Institutes of BioMedical Science, Cambridge, MA, USA
| | - Menaka V Sanghvi
- Pharmacokinetic Sciences, Novartis Institutes of BioMedical Science, Cambridge, MA, USA
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9
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Dickson CJ, Hornak V, Bednarczyk D, Duca JS. Using Membrane Partitioning Simulations To Predict Permeability of Forty-Nine Drug-Like Molecules. J Chem Inf Model 2018; 59:236-244. [DOI: 10.1021/acs.jcim.8b00744] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Callum J. Dickson
- Computer-Aided Drug Discovery, Global Discovery Chemistry, Novartis Institutes for BioMedical Research, 181 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Viktor Hornak
- Computer-Aided Drug Discovery, Global Discovery Chemistry, Novartis Institutes for BioMedical Research, 181 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Dallas Bednarczyk
- PK Sciences, Novartis Institutes for BioMedical Research, 250 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Jose S. Duca
- Computer-Aided Drug Discovery, Global Discovery Chemistry, Novartis Institutes for BioMedical Research, 181 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
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Boiselle C, Bednarczyk D. The Selection and Assessment of a Low‐Efflux MDCK Cell Line for use in a High‐Throughput Permeability Screening Assay. FASEB J 2015. [DOI: 10.1096/fasebj.29.1_supplement.939.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Carri Boiselle
- Metabolism and Pharmacokinetics Novartis Institutes for Biomedical ResearchCambridgeMassachusettsUnited States
| | - Dallas Bednarczyk
- Metabolism and Pharmacokinetics Novartis Institutes for Biomedical ResearchCambridgeMassachusettsUnited States
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Smigiel R, Lebioda A, Blaszczyński M, Korecka K, Czauderna P, Korlacki W, Jakubiak A, Bednarczyk D, Maciejewski H, Wizinska P, Sasiadek MM, Patkowski D. Alternations in genes expression of pathway signaling in esophageal tissue with atresia: results of expression microarray profiling. Dis Esophagus 2015; 28:229-33. [PMID: 24460849 DOI: 10.1111/dote.12173] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Esophageal atresia (EA) is a congenital defect of the esophagus involving the interruption of the esophagus with or without connection to the trachea (tracheoesophageal fistula [TEF]). EA/TEF may occur as an isolated anomaly, may be part of a complex of congenital defects (syndromic), or may develop within the context of a known syndrome or association. The molecular mechanisms underlying the development of EA are poorly understood. It is supposed that a combination of multigenic factors and epigenetic modification of genes play a role in its etiology. The aim of our work was to assess the human gene expression microarray study in esophageal tissue samples. Total RNA was extracted from 26 lower pouches of esophageal tissue collected during thoracoscopic EA repair in neonates with the isolated (IEA) and the syndromic form (SEA). We identified 787 downregulated and 841 upregulated transcripts between SEA and controls, and about 817 downregulated and 765 upregulated probes between IEA and controls. Fifty percent of these genes showed differential expression specific for either IEA or SEA. Functional pathway analysis revealed substantial enrichment for Wnt and Sonic hedgehog, as well as cytokine and chemokine signaling pathways. Moreover, we performed reverse transcription polymerase chain reaction study in a group of SHH and Wnt pathways genes with differential expression in microarray profiling to confirm the microarray expression results. We verified the altered expression in SFRP2 gene from the Wnt pathway as well as SHH, GLI1, GLI2, and GLI3 from the Sonic hedgehog pathway. The results suggest an important role of these pathways and genes for EA/TEF etiology.
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Affiliation(s)
- R Smigiel
- Department of Genetics, Wroclaw Medical University, Wrocław, Poland
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13
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Kefelegn A, Bednarczyk D. Delavirdine is Substrate of Bcrp and P‐gp. FASEB J 2015. [DOI: 10.1096/fasebj.29.1_supplement.939.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Adey Kefelegn
- Metabolism & Pharmacokinetics Novartis Institutes for BioMedical Research, Inc.CambridgeMAUnited States
| | - Dallas Bednarczyk
- Metabolism & Pharmacokinetics Novartis Institutes for BioMedical Research, Inc.CambridgeMAUnited States
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14
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Fu J, Tjandra M, Becker C, Bednarczyk D, Capparelli M, Elling R, Hanna I, Fujimoto R, Furegati M, Karur S, Kasprzyk T, Knapp M, Leung K, Li X, Lu P, Mergo W, Miault C, Ng S, Parker D, Peng Y, Roggo S, Rivkin A, Simmons RL, Wang M, Wiedmann B, Weiss AH, Xiao L, Xie L, Xu W, Yifru A, Yang S, Zhou B, Sweeney ZK. Potent nonimmunosuppressive cyclophilin inhibitors with improved pharmaceutical properties and decreased transporter inhibition. J Med Chem 2014; 57:8503-16. [PMID: 25310383 DOI: 10.1021/jm500862r] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Nonimmunosuppressive cyclophilin inhibitors have demonstrated efficacy for the treatment of hepatitis C infection (HCV). However, alisporivir, cyclosporin A, and most other cyclosporins are potent inhibitors of OATP1B1, MRP2, MDR1, and other important drug transporters. Reduction of the side chain hydrophobicity of the P4 residue preserves cyclophilin binding and antiviral potency while decreasing transporter inhibition. Representative inhibitor 33 (NIM258) is a less potent transporter inhibitor relative to previously described cyclosporins, retains anti-HCV activity in cell culture, and has an acceptable pharmacokinetic profile in rats and dogs. An X-ray structure of 33 bound to rat cyclophilin D is reported.
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Affiliation(s)
- Jiping Fu
- Novartis Institutes for Biomedical Research , 4560 Horton Street, Emeryville, California 94608, United States
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Ellens H, Deng S, Coleman J, Bentz J, Taub ME, Ragueneau-Majlessi I, Chung SP, Herédi-Szabó K, Neuhoff S, Palm J, Balimane P, Zhang L, Jamei M, Hanna I, O'Connor M, Bednarczyk D, Forsgard M, Chu X, Funk C, Guo A, Hillgren KM, Li L, Pak AY, Perloff ES, Rajaraman G, Salphati L, Taur JS, Weitz D, Wortelboer HM, Xia CQ, Xiao G, Yamagata T, Lee CA. Application of receiver operating characteristic analysis to refine the prediction of potential digoxin drug interactions. Drug Metab Dispos 2013; 41:1367-74. [PMID: 23620486 DOI: 10.1124/dmd.112.050542] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In the 2012 Food and Drug Administration (FDA) draft guidance on drug-drug interactions (DDIs), a new molecular entity that inhibits P-glycoprotein (P-gp) may need a clinical DDI study with a P-gp substrate such as digoxin when the maximum concentration of inhibitor at steady state divided by IC₅₀ ([I₁]/IC₅₀) is ≥0.1 or concentration of inhibitor based on highest approved dose dissolved in 250 ml divide by IC₅₀ ([I₂]/IC₅₀) is ≥10. In this article, refined criteria are presented, determined by receiver operating characteristic analysis, using IC₅₀ values generated by 23 laboratories. P-gp probe substrates were digoxin for polarized cell-lines and N-methyl quinidine or vinblastine for P-gp overexpressed vesicles. Inhibition of probe substrate transport was evaluated using 15 known P-gp inhibitors. Importantly, the criteria derived in this article take into account variability in IC₅₀ values. Moreover, they are statistically derived based on the highest degree of accuracy in predicting true positive and true negative digoxin DDI results. The refined criteria of [I₁]/IC₅₀ ≥ 0.03 and [I₂]/IC₅₀ ≥ 45 and FDA criteria were applied to a test set of 101 in vitro-in vivo digoxin DDI pairs collated from the literature. The number of false negatives (none predicted but DDI observed) were similar, 10 and 12%, whereas the number of false positives (DDI predicted but not observed) substantially decreased from 51 to 40%, relative to the FDA criteria. On the basis of estimated overall variability in IC₅₀ values, a theoretical 95% confidence interval calculation was developed for single laboratory IC₅₀ values, translating into a range of [I₁]/IC₅₀ and [I₂]/IC₅₀ values. The extent by which this range falls above the criteria is a measure of risk associated with the decision, attributable to variability in IC₅₀ values.
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Affiliation(s)
- Harma Ellens
- Drug Metabolism and Pharmacokinetics, GlaxoSmithKline Pharmaceuticals, King of Prussia, Pennsylvania, USA
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16
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Bentz J, O'Connor MP, Bednarczyk D, Coleman J, Lee C, Palm J, Pak YA, Perloff ES, Reyner E, Balimane P, Brännström M, Chu X, Funk C, Guo A, Hanna I, Herédi-Szabó K, Hillgren K, Li L, Hollnack-Pusch E, Jamei M, Lin X, Mason AK, Neuhoff S, Patel A, Podila L, Plise E, Rajaraman G, Salphati L, Sands E, Taub ME, Taur JS, Weitz D, Wortelboer HM, Xia CQ, Xiao G, Yabut J, Yamagata T, Zhang L, Ellens H. Variability in P-glycoprotein inhibitory potency (IC₅₀) using various in vitro experimental systems: implications for universal digoxin drug-drug interaction risk assessment decision criteria. Drug Metab Dispos 2013; 41:1347-66. [PMID: 23620485 DOI: 10.1124/dmd.112.050500] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A P-glycoprotein (P-gp) IC₅₀ working group was established with 23 participating pharmaceutical and contract research laboratories and one academic institution to assess interlaboratory variability in P-gp IC₅₀ determinations. Each laboratory followed its in-house protocol to determine in vitro IC₅₀ values for 16 inhibitors using four different test systems: human colon adenocarcinoma cells (Caco-2; eleven laboratories), Madin-Darby canine kidney cells transfected with MDR1 cDNA (MDCKII-MDR1; six laboratories), and Lilly Laboratories Cells--Porcine Kidney Nr. 1 cells transfected with MDR1 cDNA (LLC-PK1-MDR1; four laboratories), and membrane vesicles containing human P-glycoprotein (P-gp; five laboratories). For cell models, various equations to calculate remaining transport activity (e.g., efflux ratio, unidirectional flux, net-secretory-flux) were also evaluated. The difference in IC₅₀ values for each of the inhibitors across all test systems and equations ranged from a minimum of 20- and 24-fold between lowest and highest IC₅₀ values for sertraline and isradipine, to a maximum of 407- and 796-fold for telmisartan and verapamil, respectively. For telmisartan and verapamil, variability was greatly influenced by data from one laboratory in each case. Excluding these two data sets brings the range in IC₅₀ values for telmisartan and verapamil down to 69- and 159-fold. The efflux ratio-based equation generally resulted in severalfold lower IC₅₀ values compared with unidirectional or net-secretory-flux equations. Statistical analysis indicated that variability in IC₅₀ values was mainly due to interlaboratory variability, rather than an implicit systematic difference between test systems. Potential reasons for variability are discussed and the simplest, most robust experimental design for P-gp IC₅₀ determination proposed. The impact of these findings on drug-drug interaction risk assessment is discussed in the companion article (Ellens et al., 2013) and recommendations are provided.
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Affiliation(s)
- Joe Bentz
- Department of Biology, Drexel University, Philadelphia, PA, USA
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17
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Bednarczyk D, Smigiel R, Patkowski D, Laczmanska I, Lebioda A, Laczmanski L, Sasiadek MM. Normal exon copy number of the GLI2 and GLI3 genes in patients with esophageal atresia. Dis Esophagus 2013; 26:678-81. [PMID: 23442119 DOI: 10.1111/dote.12036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Esophageal atresia (EA) is a congenital developmental defect of the alimentary tract concerning the interruption of the esophagus with or without connection to the trachea. The incidence of EA is 1 in 3000-3500 of live-born infants, and occurs in both isolated and syndromic (in combination with abnormalities in other organ systems) forms. The molecular mechanisms underlying the development of EA are poorly understood. Knockout studies in mice indicate that genes like Sonic hedgehog, Gli2, and Gli3 play a role in the etiology of EA. These facts led us to hypothesize that Sonic hedgehog-GLI gene rearrangements are associated with EA in humans. To test this hypothesis, we screened patients with isolated and syndromic EA for GLI2 and/or GLI3 microrearrangements using methods to estimate the copy number (Multiplex Ligation-dependent Probe Amplification, real-time polymerase chain reaction). To our best knowledge this is the first study assessing copy number of GLI2 and GLI3 genes in patients with EA.
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Affiliation(s)
- D Bednarczyk
- Department of Genetics, Wroclaw Medical University, Wroclaw, Poland
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18
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Lucero ML, Gonzalo A, Ganza A, Leal N, Soengas I, Ioja E, Gedey S, Jahic M, Bednarczyk D. Interactions of bilastine, a new oral H₁ antihistamine, with human transporter systems. Drug Chem Toxicol 2012; 35 Suppl 1:8-17. [PMID: 22616811 DOI: 10.3109/01480545.2012.682653] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Membrane transporters play a significant role in facilitating transmembrane drug movement. For new pharmacological agents, it is important to evaluate potential interactions (e.g., substrate specificity and/or inhibition) with human transporters that may affect their pharmacokinetics, efficacy, or toxicity. Bilastine is a new nonsedating H₁ antihistamine indicated for the treatment of allergic rhinoconjunctivitis and urticaria. The in vitro inhibitory effects of bilastine were assessed on 12 human transporters: four efflux [multidrug resistance protein 1 (MDR1) or P-glycoprotein, breast cancer resistance protein (BCRP), multidrug resistance associated protein 2 (MRP2), and bile salt export pump) and eight uptake transporters (sodium taurocholate cotransporting polypeptide, organic cation transporter (OCT)1, organic anion transporter (OAT)1, OAT3, OCT2, OATP2B1, OATP1B1, and OATP1B3). Only mild inhibition was found for MDR1-, OCT1-, and OATP2B1-mediated transport of probe substrates at the highest bilastine concentration assayed (300 μM; half-maximal inhibitory concentration: ≥300 μM). Bilastine transport by MDR1, BCRP, OAT1, OAT3, and OCT2 was also investigated in vitro. Only MDR1 active transport of bilastine was relevant, whereas it did not appear to be a substrate of OCT2, OAT1, or OAT3, nor was it transported substantially by BCRP. Drug-drug interactions resulting from bilastine inhibition of drug transporters that would be generally regarded as clinically relevant are unlikely. Additionally, bilastine did not appear to be a substrate of human BCRP, OAT1, OAT3, or OCT2 and thus is not a potential victim of inhibitors of these transporters. On the other hand, based on in vitro evaluation, clinically relevant interactions with MDR1 inhibitors are anticipated.
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19
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Bednarczyk D. Fluorescence-based assays for the assessment of drug interaction with the human transporters OATP1B1 and OATP1B3. Anal Biochem 2010; 405:50-8. [PMID: 20540932 DOI: 10.1016/j.ab.2010.06.012] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2010] [Revised: 05/31/2010] [Accepted: 06/04/2010] [Indexed: 11/17/2022]
Abstract
Hepatic disposition plays a significant role in the pharmacokinetics and pharmacodynamics of a variety of drugs. Sinusoidal membrane transporters have been shown to participate in the hepatic disposition of many pharmaceuticals. Two sinusoidal membrane transporters with an established role in hepatic disposition are OATP1B1 and OATP1B3 (organic anion-transporting polypeptides 1B1 and 1B3, respectively). OATP1B1 and OATP1B3 have been implicated in the hepatic uptake of statin drugs, and polymorphisms linked to OATP1B1 have been associated with deleterious patient endpoints. As a result, OATP1B1 and OATP1B3 represent sites for potential drug-drug interactions. Numerous methods exist for identifying potential drug-drug interactions with transporters. However, relatively few offer the convenience and speed of fluorescence-based assays. Here a fluorescence-based assay was developed for measuring the OATP1B1- and OATP1B3-mediated transport of 8-fluorescein-cAMP (8-FcA). The OATP1B1- and OATP1B3-mediated transport of 8-FcA was time dependent and saturable (K(m)=2.9 and 1.8 microM, V(max)=0.20 and 0.33 pmol/min/cm(2), respectively). Molecules known to interact with OATPs, including cyclosporin A, rifampicin, and glibenclamide, each demonstrated concentration-dependent inhibition of 8-FcA transport by OATP1B1 and OATP1B3. The in vitro fluorescence-based assays described here using 8-FcA as the substrate are convenient and rapid and have utility in screening drug candidates for potential drug-drug interactions with OATP1B1 and OATP1B3.
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20
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Kowalczyk R, Bednarczyk D, Folwarczny W, Szpak R, Skrzypulec V. T12-P-03 Psychosexual disturbances in patients HIV infected - preliminary qustionnaire study. Sexologies 2008. [DOI: 10.1016/s1158-1360(08)72976-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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21
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Kowalczyk R, Bednarczyk D, Giemza G, Skrzypulec V. T12-P-02 Knowledge of sexually transmitted disease risk among women who have sex with women. Sexologies 2008. [DOI: 10.1016/s1158-1360(08)72975-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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22
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Reddy Aavula B, Ahad Ali M, Mash EA, Bednarczyk D, Wright SH. Synthesis and Fluorescence of N,N,N‐Trimethyl‐2‐[methyl(7‐nitrobenzo[c][l,2,5]oxadiazol‐4‐yl) amino]ethanaminium Iodide, a pH‐Insensitive Reporter of Organic Cation Transport. SYNTHETIC COMMUN 2006. [DOI: 10.1080/00397910500446597] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
| | - M. Ahad Ali
- a Department of Chemistry , University of Arizona , Tucson , Arizona , USA
| | - Eugene A. Mash
- a Department of Chemistry , University of Arizona , Tucson , Arizona , USA
| | - Dallas Bednarczyk
- b Department of Physiology , University of Arizona , Tucson , Arizona , USA
| | - Stephen H. Wright
- b Department of Physiology , University of Arizona , Tucson , Arizona , USA
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23
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Bednarczyk D, Ekins S, Wikel JH, Wright SH. Influence of molecular structure on substrate binding to the human organic cation transporter, hOCT1. Mol Pharmacol 2003; 63:489-98. [PMID: 12606755 DOI: 10.1124/mol.63.3.489] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Organic cation transporters play a critical role in the elimination of therapeutic compounds in the liver and the kidney. We used computational quantitative structure activity approaches to predict molecular features that influence interaction with the human ortholog of the organic cation transporter (hOCT1). [(3)H]tetraethylammonium uptake in HeLa cells stably expressing hOCT1 was inhibited to varying extents by a diverse set of 30 molecules. A subset of 22 of these was used to produce, using Catalyst, a pharmacophore that consisted of three hydrophobic features and a positive ionizable feature. The correlation coefficient of observed versus predicted IC(50) was 0.86 for this training set, which was superior to calculated logP alone (r = 0.73) as a predictor of hOCT1 inhibition. A descriptor-based quantitative structure-activity relationship study using Cerius(2) resulted in an equation relating five molecular descriptors to log IC(50) with a correlation coefficient of 0.95. Furthermore, a group of phenylpyridinium and quinolinium compounds were used to investigate the spatial limitations of the hOCT1 binding site. The affinity for hOCT was higher for 4-phenylpyridiniums > 3-phenylpyridiniums > quinolinium, indicating that substrate affinity was influenced by the distribution of hydrophobic mass. In addition, supraplanar hydrophobic mass was found to increase the affinity for binding hOCT1. These results indicate how a combination of computational and in vitro approaches may yield insight into the binding affinity of transporters and may be applicable to predicting these properties for new therapeutics.
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Affiliation(s)
- Dallas Bednarczyk
- Department of Physiology, University of Arizona, Tucson, Arizona, USA
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24
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Dmochowska B, Bednarczyk D, Nowacki A, Konitz A, Wojnowski W, Wiśniewski A. Preparation, chemical and crystal structures of N-(2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-beta-D-glucopyranosyl)pyridinium chloride. Carbohydr Res 2000; 329:703-7. [PMID: 11128599 DOI: 10.1016/s0008-6215(00)00215-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Preparation and isolation of N-(2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-beta-D-glucopyranosyl)pyridinium chloride are described. Its structure was determined by 1H NMR spectroscopy and X-ray analysis. X-ray crystallography revealed that the salt crystallizes with one molecule of water. Ab initio calculations were used to determine charges on atoms in the cation of the title compound.
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Affiliation(s)
- B Dmochowska
- Department of Chemistry, University of Gdańsk, Poland
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25
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Bednarczyk D, Kaca W, Myszka H, Serwecińska L, Smiatacz Z, Zaborowski A. The synthesis of diosgenyl 2-amino-2-deoxy-beta-D-glucopyranoside hydrochloride. Carbohydr Res 2000; 328:249-52. [PMID: 11072831 DOI: 10.1016/s0008-6215(00)00199-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The N-trifluoroacetyl- and N-tetrachlorophthaloyl-protected bromide of D-glucosamine has been used for the first time as a glycosyl donor for the glycosylation of diosgenin [(25R)-spirost-5-en-3beta-ol]. Both 1,3,4,6-tetra-O-acetyl-2-deoxy-2-trifluoroacetamido-beta-D-glucopy ranoside and 1,3,4,6-tetra-O-acetyl-2-deoxy-2-tetrachlorophthalimido-alpha,beta -D-glucopyranoside were transformed into the appropriate glycosyl bromides. These reacted with diosgenin under mild conditions, using silver triflate as a promoter, and gave the corresponding protected diosgenyl glycosides. Each was deprotected to give diosgenyl 2-amino-2-deoxy-beta-D-glucopyranoside hydrochloride. The structures of the new glycosides were established by 1H NMR spectroscopy.
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Affiliation(s)
- D Bednarczyk
- Faculty of Chemistry, University of Gdańsk, Poland
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26
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Bednarczyk D, Mash EA, Aavula BR, Wright SH. NBD-TMA: a novel fluorescent substrate of the peritubular organic cation transporter of renal proximal tubules. Pflugers Arch 2000; 440:184-92. [PMID: 10864014 DOI: 10.1007/s004240000283] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Traditionally, the measurement of transport activity has employed radiolabeled compounds. The resulting experimental procedures do not measure transport in real time and are limited in temporal and spatial resolution. The use of epifluorescence microscopy provides the ability to measure transport activity in real time with high temporal and spatial resolution. Using epifluorescence microscopy we characterized the transport of the fluorescent organic cation, [2-(4-nitro-2,1,3-benzoxadiazol-7-yl)aminoethyl]trimethylammonium (NBD-TMA+, MW 266). NBD-TMA+ has structural characteristics common to other secreted organic cations and is fluorescent (lambda(ex)=458 nm; lambda(em)=530 nm). The excitation and emission spectra are insensitive to changes in [Cl-] and minimally sensitive to pH in the physiologically relevant range (pH 5.0-7.4). A microscope equipped with a photon-detection system was used to measure accumulation of NBD-TMA+ by isolated rabbit renal proximal tubules. Accumulation of NBD-TMA+ by proximal tubules was time dependent and saturable (Michaelis-Menten constant Km 12 microM). Proximal tubule accumulation of NBD-TMA+ was inhibited by the organic cations tetraethylammonium (TEA+) (apparent inhibitory constant K(app)TEA 134 microM), cimetidine, and N1-methylnicotinamide (NMN). Our experimental results provide strong evidence that NBD-TMA+ is transported by one or more of the basolateral organic cation transporters involved in the renal secretion of this chemical class of compound. This fluorescent substrate provides a sensitive means of investigating organic cation transport.
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Affiliation(s)
- D Bednarczyk
- Dept. of Physiology, College of Medicine, University of Arizona, Tucson 85724, USA
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27
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Gekle M, Mildenberger S, Sauvant C, Bednarczyk D, Wright SH, Dantzler WH. Inhibition of initial transport rate of basolateral organic anion carrier in renal PT by BK and phenylephrine. Am J Physiol 1999; 277:F251-6. [PMID: 10444580 DOI: 10.1152/ajprenal.1999.277.2.f251] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effect of ligands for phospholipase C-coupled receptors and of protein kinase C (PKC) stimulation with phorbol ester [phorbol 12-myristate 13-acetate (PMA)] or 1,2-dioctanoyl-sn-glycerol on the activity of the basolateral organic anion transporter (OAT) in S2 segments of single, nonperfused rabbit proximal tubules (PT) was measured with the use of fluorescein and epifluorescence microscopy. The initial uptake rate (25 s, OAT activity) was measured in real time by using conditions similar to those found in vivo. Stimulation of PKC with PMA or 1,2-dioctanoyl-sn-glycerol led to an inhibition of OAT activity, which could be prevented by 10(-7) mol/l of the PKC-specific inhibitor bisindolylmaleimide. The alpha(1)-receptor agonist phenylephrine as well as the peptide hormone bradykinin induced a reversible decrease of OAT activity, which was prevented by bisindolylmaleimide. The observed effect was not due to a decrease in the concentration of the counterion alpha-ketoglutarate or to impaired alpha-ketoglutarate recycling, because it was unchanged in the continuous presence of alpha-ketoglutarate or methyl succinate. We conclude that physiological stimuli can inhibit the activity of OAT in rabbit PT via PKC. The effect is not mediated by alterations in counterion availability but by a direct action on the OAT.
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Affiliation(s)
- M Gekle
- Institute of Physiology, University of Würzburg, 97970 Würzburg, Germany.
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28
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Sieradzki J, Mruk K, Szybiński Z, Jedrychowski W, Tarnawski A, Korzeniowska D, Bobrowski A, Huszno B, Barylak H, Bednarczyk D, Rudziński A, Marczewska M. [Goiter in school children in the Cracow Province and some indices of somatic development]. Pol Tyg Lek 1974; 29:2217-20. [PMID: 4445039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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29
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Szybiński Z, Jedrychowski W, Konieczna W, Barylak H, Bednarczyk D, Bobrowski A, Huszno B, Korzeniowska D, Marczewska M, Mruk K, Rudziński A, Sieradzki J, Tarnawski A. [Incidence of goiter is school children from the Province of Cracow in relation to their place of residence, sex and age]. Pol Tyg Lek 1974; 29:2157-60. [PMID: 4438178 DOI: pmid/4438178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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