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Luo Y, Gao J, Jiang X, Zhu L, Zhou QT, Murray M, Li J, Zhou F. Molecular Insights to the Structure-Interaction Relationships of Human Proton-Coupled Oligopeptide Transporters (PepTs). Pharmaceutics 2023; 15:2517. [PMID: 37896276 PMCID: PMC10609898 DOI: 10.3390/pharmaceutics15102517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 10/06/2023] [Accepted: 10/19/2023] [Indexed: 10/29/2023] Open
Abstract
Human proton-coupled oligopeptide transporters (PepTs) are important membrane influx transporters that facilitate the cellular uptake of many drugs including ACE inhibitors and antibiotics. PepTs mediate the absorption of di- and tri-peptides from dietary proteins or gastrointestinal secretions, facilitate the reabsorption of peptide-bound amino acids in the kidney, and regulate neuropeptide homeostasis in extracellular fluids. PepT1 and PepT2 have been the most intensively investigated of all PepT isoforms. Modulating the interactions of PepTs and their drug substrates could influence treatment outcomes and adverse effects with certain therapies. In recent studies, topology models and protein structures of PepTs have been developed. The aim of this review was to summarise the current knowledge regarding structure-interaction relationships (SIRs) of PepTs and their substrates as well as the potential applications of this information in therapeutic optimisation and drug development. Such information may provide insights into the efficacy of PepT drug substrates in patients, mechanisms of drug-drug/food interactions and the potential role of PepTs targeting in drug design and development strategies.
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Affiliation(s)
- Yining Luo
- Molecular Drug Development Group, Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Sydney 2006, Australia; (Y.L.); (J.G.); (M.M.)
| | - Jingchun Gao
- Molecular Drug Development Group, Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Sydney 2006, Australia; (Y.L.); (J.G.); (M.M.)
| | - Xukai Jiang
- National Glycoengineering Research Center, Shandong University, Qingdao 266237, China;
| | - Ling Zhu
- Macular Research Group, Save Sight Institute, Faculty of Medicine and Health, The University of Sydney, Sydney 2006, Australia;
| | - Qi Tony Zhou
- Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA;
| | - Michael Murray
- Molecular Drug Development Group, Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Sydney 2006, Australia; (Y.L.); (J.G.); (M.M.)
| | - Jian Li
- Biomedicine Discovery Institute, Department of Microbiology, Monash University, Melbourne 3800, Australia;
| | - Fanfan Zhou
- Molecular Drug Development Group, Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Sydney 2006, Australia; (Y.L.); (J.G.); (M.M.)
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2
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Gyimesi G, Hediger MA. Transporter-Mediated Drug Delivery. Molecules 2023; 28:molecules28031151. [PMID: 36770817 PMCID: PMC9919865 DOI: 10.3390/molecules28031151] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 01/12/2023] [Accepted: 01/18/2023] [Indexed: 01/27/2023] Open
Abstract
Transmembrane transport of small organic and inorganic molecules is one of the cornerstones of cellular metabolism. Among transmembrane transporters, solute carrier (SLC) proteins form the largest, albeit very diverse, superfamily with over 400 members. It was recognized early on that xenobiotics can directly interact with SLCs and that this interaction can fundamentally determine their efficacy, including bioavailability and intertissue distribution. Apart from the well-established prodrug strategy, the chemical ligation of transporter substrates to nanoparticles of various chemical compositions has recently been used as a means to enhance their targeting and absorption. In this review, we summarize efforts in drug design exploiting interactions with specific SLC transporters to optimize their therapeutic effects. Furthermore, we describe current and future challenges as well as new directions for the advanced development of therapeutics that target SLC transporters.
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Kervefors G, Kersting L, Olofsson B. Transition Metal-Free N-Arylation of Amino Acid Esters with Diaryliodonium Salts. Chemistry 2021; 27:5790-5795. [PMID: 33481266 PMCID: PMC8048889 DOI: 10.1002/chem.202005351] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Indexed: 12/31/2022]
Abstract
A transition metal-free approach for the N-arylation of amino acid derivatives has been developed. Key to this method is the use of unsymmetric diaryliodonium salts with anisyl ligands, which proved important to obtain high chemoselectivity and yields. The scope includes the transfer of both electron deficient, electron rich and sterically hindered aryl groups with a variety of different functional groups. Furthermore, a cyclic diaryliodonium salt was successfully employed in the arylation. The N-arylated products were obtained with retained enantiomeric excess.
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Affiliation(s)
- Gabriella Kervefors
- Department of Organic ChemistryArrhenius LaboratoryStockholm UniversitySE-106 91StockholmSweden
| | - Leonard Kersting
- Department of Organic ChemistryArrhenius LaboratoryStockholm UniversitySE-106 91StockholmSweden
| | - Berit Olofsson
- Department of Organic ChemistryArrhenius LaboratoryStockholm UniversitySE-106 91StockholmSweden
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4
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Recent advances in understanding prodrug transport through the SLC15 family of proton-coupled transporters. Biochem Soc Trans 2021; 48:337-346. [PMID: 32219385 PMCID: PMC7200629 DOI: 10.1042/bst20180302] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 02/15/2020] [Accepted: 03/04/2020] [Indexed: 12/28/2022]
Abstract
Solute carrier (SLC) transporters play important roles in regulating the movement of small molecules and ions across cellular membranes. In mammals, they play an important role in regulating the uptake of nutrients and vitamins from the diet, and in controlling the distribution of their metabolic intermediates within the cell. Several SLC families also play an important role in drug transport and strategies are being developed to hijack SLC transporters to control and regulate drug transport within the body. Through the addition of amino acid and peptide moieties several novel antiviral and anticancer agents have been developed that hijack the proton-coupled oligopeptide transporters, PepT1 (SCL15A1) and PepT2 (SLC15A2), for improved intestinal absorption and renal retention in the body. A major goal is to understand the rationale behind these successes and expand the library of prodrug molecules that utilise SLC transporters. Recent co-crystal structures of prokaryotic homologues of the human PepT1 and PepT2 transporters have shed important new insights into the mechanism of prodrug recognition. Here, I will review recent developments in our understanding of ligand recognition and binding promiscuity within the SLC15 family, and discuss current models for prodrug recognition.
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Prabhala BK, Rahman M, Nour-Eldin HH, Jørgensen FS, Mirza O. PTR2/POT/NPF transporters: what makes them tick? ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2020; 123:219-240. [PMID: 33485485 DOI: 10.1016/bs.apcsb.2020.10.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
PTR2/POT/NPF are a family of primarily proton coupled transporters that belong to the major facilitator super family and are found across most kingdoms of life. They are involved in uptake of nutrients, hormones, ions and several orally administered drug molecules. A wealth of structural and functional data is available for this family; the similarity between the protein structural features have been discussed and investigated in detail on several occasions, however there are no reports on the unification of substrate information. In order to fill this gap, we have collected information about substrates across the entire PTR2/POT/NPF family in order to provide key insights into what makes a molecule a substrate and whether there are common features among confirmed substrates. This review will be of particular interest for researchers in the field trying to probe the mechanisms responsible for the different selectivity of these transporters at a molecular resolution, and to design novel substrates.
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Affiliation(s)
- Bala K Prabhala
- Institute of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense, Denmark
| | - Moazur Rahman
- School of Biological Sciences, University of the Punjab, Lahore, Punjab, Pakistan; Drug Discovery and Structural Biology Group, Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Punjab, Pakistan
| | - Hussam H Nour-Eldin
- DynaMo Center, Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Flemming Steen Jørgensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Osman Mirza
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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6
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Wulff N, Ernst HA, Jørgensen ME, Lambertz S, Maierhofer T, Belew ZM, Crocoll C, Motawia MS, Geiger D, Jørgensen FS, Mirza O, Nour-Eldin HH. An Optimized Screen Reduces the Number of GA Transporters and Provides Insights Into Nitrate Transporter 1/Peptide Transporter Family Substrate Determinants. FRONTIERS IN PLANT SCIENCE 2019; 10:1106. [PMID: 31632416 PMCID: PMC6785635 DOI: 10.3389/fpls.2019.01106] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 08/13/2019] [Indexed: 05/17/2023]
Abstract
Based on recent in vitro data, a relatively large number of the plant nitrate transporter 1/peptide transporter family (NPF) proteins have been suggested to function as gibberellic acid (GA) transporters. Most GA transporting NPF proteins also appear to transport other structurally unrelated phytohormones or metabolites. Several of the GAs used in previous in vitro assays are membrane permeable weak organic acids whose movement across membranes are influenced by the pH-sensitive ion-trap mechanism. Moreover, a large proportion of in vitro GA transport activities have been demonstrated indirectly via long-term yeast-based GA-dependent growth assays that are limited to detecting transport of bioactive GAs. Thus, there is a need for an optimized transport assay for identifying and characterizing GA transport. Here, we develop an improved transport assay in Xenopus laevis oocytes, wherein we directly measure movement of six different GAs across oocyte membranes over short time. We show that membrane permeability of GAs in oocytes can be predicted based on number of oxygen atoms and that several GAs do not diffuse over membranes regardless of changes in pH values. In addition, we show that small changes in internal cellular pH can result in strongly altered distribution of membrane permeable phytohormones. This prompts caution when interpreting heterologous transport activities. We use our transport assay to screen all Arabidopsis thaliana NPF proteins for transport activity towards six GAs (two membrane permeable and four non-permeable). The results presented here, significantly reduce the number of bona fide NPF GA transporters in Arabidopsis and narrow the activity to fewer subclades within the family. Furthermore, to gain first insight into the molecular determinants of substrate specificities toward organic molecules transported in the NPF, we charted all surface exposed amino acid residues in the substrate-binding cavity and correlated them to GA transport. This analysis suggests distinct residues within the substrate-binding cavity that are shared between GA transporting NPF proteins; the potential roles of these residues in determining substrate specificity are discussed.
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Affiliation(s)
- Nikolai Wulff
- DynaMo Center, Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | | | - Morten Egevang Jørgensen
- DynaMo Center, Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
- Julius-von-Sachs-Institute, Molecular Plant Physiology and Biophysics, University Würzburg, Würzburg, Germany
- Carlsberg Research Laboratory, Copenhagen, Denmark
| | - Sophie Lambertz
- DynaMo Center, Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Tobias Maierhofer
- Julius-von-Sachs-Institute, Molecular Plant Physiology and Biophysics, University Würzburg, Würzburg, Germany
| | - Zeinu Mussa Belew
- DynaMo Center, Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Christoph Crocoll
- DynaMo Center, Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Mohammed Saddik Motawia
- Center for Plant Plasticity, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Dietmar Geiger
- Julius-von-Sachs-Institute, Molecular Plant Physiology and Biophysics, University Würzburg, Würzburg, Germany
| | | | - Osman Mirza
- Department of Drug Design and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Hussam Hassan Nour-Eldin
- DynaMo Center, Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
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7
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Guo HY, Jin C, Zhang HM, Jin CM, Shen QK, Quan ZS. Synthesis and Biological Evaluation of (+)-Usnic Acid Derivatives as Potential Anti- Toxoplasma gondii Agents. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:9630-9642. [PMID: 31365255 DOI: 10.1021/acs.jafc.9b02173] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Six series of (+)-usnic acid derivatives were synthesized. The IC50 values of these compounds were determined in T. gondii infected HeLa cells (μM) and in HeLa cells (μM), and their selectivity indexes (SI) were calculated. In vitro, most of the derivatives tested in this study exhibited more anti activity than that of the parent compound (+)-usnic acid and the positive control drugs. Among these derivatives, methyl (E)-(1-(6-acetyl-7,9-dihydroxy-8,9b-dimethyl-1,3-dioxo-3,9b-dihydrodibenzo[b,d]furan-2(1H)-ylidene)ethyl)phenylalaninate (D3) showed the most effective anti-T. gondii activity (selectivity >2.77). In comparison with the clinically used positive control drugs sulfadiazine (selectivity 1.15), pyrimethamine (selectivity 0.89), spiramycin (selectivity 0.72), and the lead compound (+)-usnic acid (selectivity 0.96), D3 showed better results in vitro. Furthermore, D3 and (E)-6-acetyl-7,9-dihydroxy-8,9b-dimethyl-2-(1-(quinolin-6-ylamino)ethylidene)dibenzo[b,d]furan-1,3(2H,9bH)-dione (F3) had greater inhibitory effects on T. gondii (inhibition rates 76.0% and 64.6%) in vivo in comparison to spiramycin (inhibition rate 55.2%); in the peritoneal cavity of mice, the number of tachyzoites was significantly reduced (p < 0.001) in vivo. Additionally, some biochemical parameters were measured and spleen indexes were comprehensively evaluated, and the results indicated that mice treated with both compound D3 and compound F3 showed reduced hepatotoxicity and significantly enhanced antioxidative effects in comparison to the normal group. Granuloma and cyst formation were effected by the inhibition of compound D3 and compound F3 in liver sections. Overall, these results indicated that D3 and F3 for use as anti-T. gondii agents are promising lead compounds.
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Affiliation(s)
- Hong-Yan Guo
- Key Laboratory of Natural Resources and Functional Molecules of the Changbai Mountain, Affiliated Ministry of Education, College of Pharmacy , Yanbian University , Yanji , Jilin 133002 , People's Republic of China
| | - ChunMei Jin
- Key Laboratory of Natural Resources and Functional Molecules of the Changbai Mountain, Affiliated Ministry of Education, College of Pharmacy , Yanbian University , Yanji , Jilin 133002 , People's Republic of China
| | - Hai-Ming Zhang
- Key Laboratory of Natural Resources and Functional Molecules of the Changbai Mountain, Affiliated Ministry of Education, College of Pharmacy , Yanbian University , Yanji , Jilin 133002 , People's Republic of China
| | - Chun-Mei Jin
- Key Laboratory of Natural Resources and Functional Molecules of the Changbai Mountain, Affiliated Ministry of Education, College of Pharmacy , Yanbian University , Yanji , Jilin 133002 , People's Republic of China
| | - Qing-Kun Shen
- Key Laboratory of Natural Resources and Functional Molecules of the Changbai Mountain, Affiliated Ministry of Education, College of Pharmacy , Yanbian University , Yanji , Jilin 133002 , People's Republic of China
| | - Zhe-Shan Quan
- Key Laboratory of Natural Resources and Functional Molecules of the Changbai Mountain, Affiliated Ministry of Education, College of Pharmacy , Yanbian University , Yanji , Jilin 133002 , People's Republic of China
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8
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Structural basis for prodrug recognition by the SLC15 family of proton-coupled peptide transporters. Proc Natl Acad Sci U S A 2019; 116:804-809. [PMID: 30602453 PMCID: PMC6338836 DOI: 10.1073/pnas.1813715116] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Poor oral bioavailability is one of the leading causes of compound failure in drug development and a major challenge for the pharmaceutical industry. A successful approach to address this challenge has been the development of prodrugs that target the intestinal peptide transporter, PepT1 (SLC15A1). PepT1 exhibits a remarkably promiscuous binding site and is known to transport many different drug molecules, making it an excellent target for prodrug design and delivery. However, the structural basis for drug recognition remains largely unknown. Here we present the structure of a bacterial homolog of PepT1 bound to both an antiviral prodrug, valacyclovir, and anticancer drug 5-aminolevulinic acid. These structures enable a pharmacophore model to be developed that will aid future prodrug design. A major challenge in drug development is the optimization of intestinal absorption and cellular uptake. A successful strategy has been to develop prodrug molecules, which hijack solute carrier (SLC) transporters for active transport into the body. The proton-coupled oligopeptide transporters, PepT1 and PepT2, have been successfully targeted using this approach. Peptide transporters display a remarkable capacity to recognize a diverse library of di- and tripeptides, making them extremely promiscuous and major contributors to the pharmacokinetic profile of several important drug classes, including beta-lactam antibiotics and antiviral and antineoplastic agents. Of particular interest has been their ability to recognize amino acid and peptide-based prodrug molecules, thereby providing a rational approach to improving drug transport into the body. However, the structural basis for prodrug recognition has remained elusive. Here we present crystal structures of a prokaryotic homolog of the mammalian transporters in complex with the antiviral prodrug valacyclovir and the peptide-based photodynamic therapy agent, 5-aminolevulinic acid. The valacyclovir structure reveals that prodrug recognition is mediated through both the amino acid scaffold and the ester bond, which is commonly used to link drug molecules to the carrier’s physiological ligand, whereas 5-aminolevulinic acid makes far fewer interactions compared with physiological peptides. These structures provide a unique insight into how peptide transporters interact with xenobiotic molecules and provide a template for further prodrug development.
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9
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Zhang HB, Shen QK, Wang H, Jin C, Jin CM, Quan ZS. Synthesis and evaluation of novel arctigenin derivatives as potential anti-Toxoplasma gondii agents. Eur J Med Chem 2018; 158:414-427. [PMID: 30237124 DOI: 10.1016/j.ejmech.2018.08.087] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2018] [Revised: 08/15/2018] [Accepted: 08/29/2018] [Indexed: 12/20/2022]
Abstract
Four new series of arctigenin derivatives were designed, synthesised, and evaluated for their anti-Toxoplasma gondii activity in vitro and in vivo. Among the synthesised compounds, 4-(3,4-dimethoxybenzyl)-3-(4-((1-(2-fluorobenzyl)-1H- 1,2,3-triazol-4-yl)methoxy)-3-methoxybenzyl)dihydrofuran-2(3H)-one (D4) exhibited the most potent anti-T. gondii activity and low cytotoxicity (IC50 in T. gondii: 17.1 μM; IC50 in HeLa cells: ≥ 600.0 μM; Selectivity: 35.09), demonstrating better results than the lead compound arctigenin (IC50 in T. gondii: 586.4 μM; IC50 in HeLa cells: 572.7 μM; Selectivity: 0.98) and the clinically applied positive-control drug spiramycin (IC50 in T. gondi: 262.2 μM; IC50 in HeLa cells: 189.0 μM; Selectivity: 0.72) in vitro. Furthermore, 2-(4-((4-(3,4-dimethoxybenzyl)-2-oxotetrahydrofuran-3-yl)methyl)-2- methoxyphenoxy)N-phenylacetamide (E5) had better inhibitory effects on T. gondii in vivo than spiramycin did. Compound D4 and E5 not only significantly reduced the number of tachyzoites in the peritoneal cavity of mice, but also resulted in their partial malformation (P < 0.05) in vivo. The determination of liver and spleen index and biochemical parameters, such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), glutathione (GSH) and malondialdehyde (MDA), were comprehensively evaluated for compound D4 and E5's anti-T. gondii activity and some damage to the liver. In addition, the results of a docking study of D4 into the T. gondii calcium-dependent protein kinase 1 (TgCDPK1) receptor protein-binding site revealed that its mode of action was possibly as a TgCDPK1 inhibitor. Overall, the results revealed that D4 and E5 are promising lead compounds for the further development and identification of arctigenin derivatives as anti-T. gondii agents.
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Affiliation(s)
- Hai-Bin Zhang
- Key Laboratory of Natural Resources and Functional Molecules of the Changbai Mountain, Affiliated Ministry of Education, College of Pharmacy, Yanbian University, Yanji, Jilin, 133002, China
| | - Qing-Kun Shen
- Key Laboratory of Natural Resources and Functional Molecules of the Changbai Mountain, Affiliated Ministry of Education, College of Pharmacy, Yanbian University, Yanji, Jilin, 133002, China
| | - Hui Wang
- Key Laboratory of Natural Resources and Functional Molecules of the Changbai Mountain, Affiliated Ministry of Education, College of Pharmacy, Yanbian University, Yanji, Jilin, 133002, China
| | - Chunmei Jin
- Key Laboratory of Natural Resources and Functional Molecules of the Changbai Mountain, Affiliated Ministry of Education, College of Pharmacy, Yanbian University, Yanji, Jilin, 133002, China
| | - Chun-Mei Jin
- Key Laboratory of Natural Resources and Functional Molecules of the Changbai Mountain, Affiliated Ministry of Education, College of Pharmacy, Yanbian University, Yanji, Jilin, 133002, China.
| | - Zhe-Shan Quan
- Key Laboratory of Natural Resources and Functional Molecules of the Changbai Mountain, Affiliated Ministry of Education, College of Pharmacy, Yanbian University, Yanji, Jilin, 133002, China.
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10
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Minhas GS, Bawdon D, Herman R, Rudden M, Stone AP, James AG, Thomas GH, Newstead S. Structural basis of malodour precursor transport in the human axilla. eLife 2018; 7:e34995. [PMID: 29966586 PMCID: PMC6059767 DOI: 10.7554/elife.34995] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 06/23/2018] [Indexed: 01/10/2023] Open
Abstract
Mammals produce volatile odours that convey different types of societal information. In Homo sapiens, this is now recognised as body odour, a key chemical component of which is the sulphurous thioalcohol, 3-methyl-3-sulfanylhexan-1-ol (3M3SH). Volatile 3M3SH is produced in the underarm as a result of specific microbial activity, which act on the odourless dipeptide-containing malodour precursor molecule, S-Cys-Gly-3M3SH, secreted in the axilla (underarm) during colonisation. The mechanism by which these bacteria recognise S-Cys-Gly-3M3SH and produce body odour is still poorly understood. Here we report the structural and biochemical basis of bacterial transport of S-Cys-Gly-3M3SH by Staphylococcus hominis, which is converted to the sulphurous thioalcohol component 3M3SH in the bacterial cytoplasm, before being released into the environment. Knowledge of the molecular basis of precursor transport, essential for body odour formation, provides a novel opportunity to design specific inhibitors of malodour production in humans.
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Affiliation(s)
- Gurdeep S Minhas
- Department of BiochemistryUniversity of OxfordOxfordUnited Kingdom
| | - Daniel Bawdon
- Department of BiologyUniversity of YorkYorkUnited Kingdom
| | - Reyme Herman
- Department of BiologyUniversity of YorkYorkUnited Kingdom
| | | | - Andrew P Stone
- Department of BiologyUniversity of YorkYorkUnited Kingdom
| | | | - Gavin H Thomas
- Department of BiologyUniversity of YorkYorkUnited Kingdom
| | - Simon Newstead
- Department of BiochemistryUniversity of OxfordOxfordUnited Kingdom
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11
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Tsume Y, Drelich AJ, Smith DE, Amidon GL. Potential Development of Tumor-Targeted Oral Anti-Cancer Prodrugs: Amino Acid and Dipeptide Monoester Prodrugs of Gemcitabine. Molecules 2017; 22:molecules22081322. [PMID: 28796151 PMCID: PMC5826767 DOI: 10.3390/molecules22081322] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 08/04/2017] [Accepted: 08/05/2017] [Indexed: 02/06/2023] Open
Abstract
One of the main obstacles for cancer therapies is to deliver medicines effectively to target sites. Since stroma cells are developed around tumors, chemotherapeutic agents have to go through stroma cells in order to reach tumors. As a method to improve drug delivery to the tumor site, a prodrug approach for gemcitabine was adopted. Amino acid and dipeptide monoester prodrugs of gemcitabine were synthesized and their chemical stability in buffers, resistance to thymidine phosphorylase and cytidine deaminase, antiproliferative activity, and uptake/permeability in HFF cells as a surrogate to stroma cells were determined and compared to their parent drug, gemcitabine. The activation of all gemcitabine prodrugs was faster in pancreatic cell homogenates than their hydrolysis in buffer, suggesting enzymatic action. All prodrugs exhibited great stability in HFF cell homogenate, enhanced resistance to glycosidic bond metabolism by thymidine phosphorylase, and deamination by cytidine deaminase compared to their parent drug. All gemcitabine prodrugs exhibited higher uptake in HFF cells and better permeability across HFF monolayers than gemcitabine, suggesting a better delivery to tumor sites. Cell antiproliferative assays in Panc-1 and Capan-2 pancreatic ductal cell lines indicated that the gemcitabine prodrugs were more potent than their parent drug gemcitabine. The transport and enzymatic profiles of gemcitabine prodrugs suggest their potential for delayed enzymatic bioconversion and enhanced resistance to metabolic enzymes, as well as for enhanced drug delivery to tumor sites, and cytotoxic activity in cancer cells. These attributes would facilitate the prolonged systemic circulation and improved therapeutic efficacy of gemcitabine prodrugs.
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Affiliation(s)
- Yasuhiro Tsume
- Department of Pharmaceutical Science, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, MI 48109-1065, USA.
| | - Adam J Drelich
- Department of Pharmaceutical Science, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, MI 48109-1065, USA.
| | - David E Smith
- Department of Pharmaceutical Science, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, MI 48109-1065, USA.
| | - Gordon L Amidon
- Department of Pharmaceutical Science, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, MI 48109-1065, USA.
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12
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Newstead S. Recent advances in understanding proton coupled peptide transport via the POT family. Curr Opin Struct Biol 2016; 45:17-24. [PMID: 27865112 DOI: 10.1016/j.sbi.2016.10.018] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Revised: 10/22/2016] [Accepted: 10/26/2016] [Indexed: 10/20/2022]
Abstract
The POT family of membrane transporters use the inwardly directed proton electrochemical gradient to drive the uptake of essential nutrients into the cell. Originally discovered in bacteria, members of the family have been found in all kingdoms of life except the archaea. A remarkable feature of the family is their diverse substrate promiscuity. Whereas in mammals and bacteria they are predominantly di- and tri-peptide transporters, in plants the family has diverged to recognize nitrate, plant defence compounds and hormones. This promiscuity has led to the development of peptide-based pro-drugs that use PepT1 and PepT2, the mammalian homologues, to improve oral drug delivery. Recent crystal structures from bacterial and plant members of the family have revealed conserved features of the ligand-binding site and provided insights into post-translational regulation. Here I review the current understanding of transport, ligand promiscuity and regulation within the POT family.
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Affiliation(s)
- Simon Newstead
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom.
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13
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Cai EB, Yang LM, Jia CX, Zhang WY, Zhao Y, Li W, Song XZ, Zheng ML. The Synthesis and Evaluation of Arctigenin Amino Acid Ester Derivatives. Chem Pharm Bull (Tokyo) 2016; 64:1466-1473. [PMID: 27383415 DOI: 10.1248/cpb.c16-0429] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The use of arctigenin (ARG), a traditional medicine with many pharmacological activities, has been restricted due to its poor solubility in water. Five amino acid derivatives of ARG have been synthesized using glycine, o-alanine, valine, leucine, and isoleucine, which have t-butyloxy carbonyl (BOC) as a protective group. In this study, we examined the effects of removing these protective groups. The results showed that the amino acid derivatives have better solubility and nitrite-clearing ability than ARG. Among the compounds tested, the amino acid derivatives without protective group were the best. Based on these results, ARG and its two amino acid derivatives without protective group (ARG8, ARG10) were selected to evaluate their anti-tumor activity in vivo at a dosage of 40 mg/kg. The results indicated that ARG8 and ARG10 both exhibit more anti-tumor activity than ARG in H22 tumor-bearing mice. The tumor inhibition rates of ARG8 and ARG10 were 69.27 and 43.58%, which was much higher than ARG. Furthermore, the mice treated with these compounds exhibited less damage to the liver, kidney and immune organs compared with the positive group. Furthermore, ARG8 and ARG10 improved the serum cytokine levels significantly compared to ARG. In brief, this study provides a method to improve the water solubility of drugs, and we also provide a reference basis for new drug development.
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Affiliation(s)
- En-Bo Cai
- College of Chinese Medicinal Material, Jilin Agricultural University
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14
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Samsudin F, Parker JL, Sansom MSP, Newstead S, Fowler PW. Accurate Prediction of Ligand Affinities for a Proton-Dependent Oligopeptide Transporter. Cell Chem Biol 2016; 23:299-309. [PMID: 27028887 PMCID: PMC4760754 DOI: 10.1016/j.chembiol.2015.11.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 10/22/2015] [Accepted: 11/04/2015] [Indexed: 12/04/2022]
Abstract
Membrane transporters are critical modulators of drug pharmacokinetics, efficacy, and safety. One example is the proton-dependent oligopeptide transporter PepT1, also known as SLC15A1, which is responsible for the uptake of the β-lactam antibiotics and various peptide-based prodrugs. In this study, we modeled the binding of various peptides to a bacterial homolog, PepTSt, and evaluated a range of computational methods for predicting the free energy of binding. Our results show that a hybrid approach (endpoint methods to classify peptides into good and poor binders and a theoretically exact method for refinement) is able to accurately predict affinities, which we validated using proteoliposome transport assays. Applying the method to a homology model of PepT1 suggests that the approach requires a high-quality structure to be accurate. Our study provides a blueprint for extending these computational methodologies to other pharmaceutically important transporter families. A hierarchical computational approach determines ligand affinities to transporters Lysine-containing dipeptides proposed to bind vertically like a tripeptide Experimental structures are vital for the accurate prediction of affinities A model of prodrug interactions to human PepT1 is suggested
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Affiliation(s)
- Firdaus Samsudin
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Joanne L Parker
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Simon Newstead
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
| | - Philip W Fowler
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
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15
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Ai Y, Kang F, Huang Z, Xue X, Lai Y, Peng S, Tian J, Zhang Y. Synthesis of CDDO-amino acid-nitric oxide donor trihybrids as potential antitumor agents against both drug-sensitive and drug-resistant colon cancer. J Med Chem 2015; 58:2452-64. [PMID: 25675144 DOI: 10.1021/jm5019302] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Seventeen CDDO-amino acid-NO donor trihybrids (4a-q) were designed and synthesized. Biological evaluation indicated that the most active compound 4c produced high levels of NO and inhibited the proliferation of drug-sensitive (HCT-8, IC50 = 0.294 μM) and drug-resistant (HCT-8/5-FU, IC50 = 0.232 μM) colon cancer cells, which were attenuated by an NO scavenger or typical substrate of PepT1. Furthermore, 4c triggered HCT-8 and HCT-8/5-FU cell apoptosis more strongly than CDDO-Me, inhibited the HIF-1α, Stat3, AKT, and ERK signaling, and induced the nitration of P-gp, MRP1, and BCRP proteins in HCT-8/5-FU cells. Finally, 4c had 4.36-5.53-fold less inhibitory activity against nontumor colon epithelial-like cells (CCD841, IC50 = 1.282 μM) in vitro and inhibited the growth of implanted human drug-resistant colon cancers in mice more potently than CDDO-Me. Together, 4c is a novel trihybrid with potent antitumor activity and may be a promising candidate for the treatment of drug-resistant colon cancer.
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Affiliation(s)
- Yong Ai
- State Key Laboratory of Natural Medicines, China Pharmaceutical University , Nanjing 210009, PR China
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16
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Sharma KK, Sharma S, Kudwal A, Jain R. Room temperature N-arylation of amino acids and peptides using copper(i) and β-diketone. Org Biomol Chem 2015; 13:4637-41. [DOI: 10.1039/c5ob00288e] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A mild and efficient Cu-catalyzed procedure for the N-arylation of zwitterionic amino acids, amino acid esters and peptides is described.
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Affiliation(s)
- Krishna K. Sharma
- Department of Medicinal Chemistry
- National Institute of Pharmaceutical Education and Research
- S. A. S. Nagar
- India
| | - Swagat Sharma
- Department of Medicinal Chemistry
- National Institute of Pharmaceutical Education and Research
- S. A. S. Nagar
- India
| | - Anurag Kudwal
- Department of Medicinal Chemistry
- National Institute of Pharmaceutical Education and Research
- S. A. S. Nagar
- India
| | - Rahul Jain
- Department of Medicinal Chemistry
- National Institute of Pharmaceutical Education and Research
- S. A. S. Nagar
- India
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17
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Jensen JM, Aduri NG, Prabhala BK, Jahnsen R, Franzyk H, Mirza O. Critical role of a conserved transmembrane lysine in substrate recognition by the proton-coupled oligopeptide transporter YjdL. Int J Biochem Cell Biol 2014; 55:311-7. [PMID: 25261786 DOI: 10.1016/j.biocel.2014.09.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 09/12/2014] [Accepted: 09/15/2014] [Indexed: 11/16/2022]
Abstract
Proton-coupled oligopeptide transporters (POTs) utilize an electrochemical proton gradient to accumulate peptides in the cytoplasm. Changing the highly conserved active-site Lys117 in the Escherichia coli POT YjdL to glutamine resulted in loss of ligand affinity as well as inability to distinguish between a dipeptide ligand and the corresponding dipeptide amide. The radically changed pH(Bulk) profiles of Lys117Gln and Lys117Arg mutants indicate an important role of Lys117 in facilitating protonation of the transporter; a notion that is supported by the close proximity of Lys117 to the conserved ExxERFxYY POT motif previously shown to be involved in proton translocation. These results point toward a novel dual role of Lys117 in direct or indirect interaction with both proton and peptide.
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Affiliation(s)
- Johanne M Jensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nanda G Aduri
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Bala K Prabhala
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Rasmus Jahnsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Henrik Franzyk
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Osman Mirza
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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18
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Lyons JA, Parker JL, Solcan N, Brinth A, Li D, Shah STA, Caffrey M, Newstead S. Structural basis for polyspecificity in the POT family of proton-coupled oligopeptide transporters. EMBO Rep 2014; 15:886-93. [PMID: 24916388 PMCID: PMC4149780 DOI: 10.15252/embr.201338403] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
An enigma in the field of peptide transport is the structural basis for ligand promiscuity, as exemplified by PepT1, the mammalian plasma membrane peptide transporter. Here, we present crystal structures of di- and tripeptide-bound complexes of a bacterial homologue of PepT1, which reveal at least two mechanisms for peptide recognition that operate within a single, centrally located binding site. The dipeptide was orientated laterally in the binding site, whereas the tripeptide revealed an alternative vertical binding mode. The co-crystal structures combined with functional studies reveal that biochemically distinct peptide-binding sites likely operate within the POT/PTR family of proton-coupled symporters and suggest that transport promiscuity has arisen in part through the ability of the binding site to accommodate peptides in multiple orientations for transport.
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Affiliation(s)
- Joseph A Lyons
- Schools of Medicine and Biochemistry & Immunology, Trinity College Dublin, Dublin, Ireland
| | - Joanne L Parker
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Nicolae Solcan
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Alette Brinth
- Schools of Medicine and Biochemistry & Immunology, Trinity College Dublin, Dublin, Ireland
| | - Dianfan Li
- Schools of Medicine and Biochemistry & Immunology, Trinity College Dublin, Dublin, Ireland
| | - Syed T A Shah
- Schools of Medicine and Biochemistry & Immunology, Trinity College Dublin, Dublin, Ireland
| | - Martin Caffrey
- Schools of Medicine and Biochemistry & Immunology, Trinity College Dublin, Dublin, Ireland
| | - Simon Newstead
- Department of Biochemistry, University of Oxford, Oxford, UK
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19
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The dipeptide monoester prodrugs of floxuridine and gemcitabine-feasibility of orally administrable nucleoside analogs. Pharmaceuticals (Basel) 2014; 7:169-91. [PMID: 24473270 PMCID: PMC3942691 DOI: 10.3390/ph7020169] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 01/15/2014] [Accepted: 01/22/2014] [Indexed: 12/19/2022] Open
Abstract
Dipeptide monoester prodrugs of floxuridine and gemcitabine were synthesized. Their chemical stability in buffers, enzymatic stability in cell homogenates, permeability in mouse intestinal membrane along with drug concentration in mouse plasma, and anti-proliferative activity in cancer cells were determined and compared to their parent drugs. Floxuridine prodrug was more enzymatically stable than floxuridine and the degradation from prodrug to parent drug works as the rate-limiting step. On the other hand, gemcitabine prodrug was less enzymatically stable than gemcitabine. Those dipeptide monoester prodrugs exhibited 2.4- to 48.7-fold higher uptake than their parent drugs in Caco-2, Panc-1, and AsPC-1 cells. Floxuridine and gemcitabine prodrugs showed superior permeability in mouse jejunum to their parent drugs and exhibited the higher drug concentration in plasma after in situ mouse perfusion. Cell proliferation assays in ductal pancreatic cancer cells, AsPC-1 and Panc-1, indicated that dipeptide prodrugs of floxuridine and gemcitabine were more potent than their parent drugs. The enhanced potency of nucleoside analogs was attributed to their improved membrane permeability. The prodrug forms of 5′-l-phenylalanyl-l-tyrosyl-floxuridine and 5′-l-phenylalanyl-l-tyrosyl-gemcitabine appeared in mouse plasma after the permeation of intestinal membrane and the first-pass effect, suggesting their potential for the development of oral dosage form for anti-cancer agents.
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20
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Fang L, Wang M, Gou S, Liu X, Zhang H, Cao F. Combination of amino acid/dipeptide with nitric oxide donating oleanolic acid derivatives as PepT1 targeting antitumor prodrugs. J Med Chem 2014; 57:1116-20. [PMID: 24422538 DOI: 10.1021/jm401634d] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
By taking advantage of the cytotoxic effect of nitric oxide (NO) and PepT1 for molecule-targeted drug delivery, a series of amino acid/dipeptide diester prodrugs of NO-donating oleanolic acid derivatives were designed and synthesized. Two prodrugs 6a and 8a showed potent cytotoxcity, which is probably due to their high PepT1 affinity and NO-releasing ability. Furthermore, the aqueous solubility of the prodrugs was also significantly enhanced because of the hydrophilic amino acid/dipeptide promoiety.
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Affiliation(s)
- Lei Fang
- Pharmaceutical Research Center and Jiangsu Province Hi-Tech Key Laboratory for Bio-Medical Research, School of Chemistry and Chemical Engineering, Southeast University , Nanjing 211189, China
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21
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Tsume Y, Incecayir T, Song X, Hilfinger JM, Amidon GL. The development of orally administrable gemcitabine prodrugs with D-enantiomer amino acids: enhanced membrane permeability and enzymatic stability. Eur J Pharm Biopharm 2013; 86:514-23. [PMID: 24361461 DOI: 10.1016/j.ejpb.2013.12.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 09/23/2013] [Accepted: 12/12/2013] [Indexed: 10/25/2022]
Abstract
Gemcitabine prodrugs with D- and L-configuration amino acids were synthesized and their chemical stability in buffers, resistance to glycosidic bond metabolism, enzymatic activation, permeability in Caco-2 cells and mouse intestinal membrane, anti-proliferation activity in cancer cell were determined and compared to that of parent drug, gemcitabine. Prodrugs containing D-configuration amino acids were enzymatically more stable than ones with L-configuration amino acids. The activation of all gemcitabine prodrugs was 1.3-17.6-fold faster in cancer cell homogenate than their hydrolysis in buffer, suggesting enzymatic action. The enzymatic activation of amino acid monoester prodrugs containing D-configuration amino acids in cell homogenates was 2.2-10.9-fold slower than one of amino acid monoester prodrugs with L-configuration amino acids. All prodrugs exhibited enhanced resistance to glycosidic bond metabolism by thymidine phosphorylase compared to parent gemcitabine. Gemcitabine prodrugs showed superior the effective permeability in mouse jejunum to gemcitabine. More importantly, the high plasma concentration of d-amino acid gemcitabine prodrugs was observed more than one of L-amino acid gemcitabine prodrugs. In general, the 5'-mono-amino acid monoester gemcitabine prodrugs exhibited higher permeability and uptake than their parent drug, gemcitabine. Cell proliferation assays in AsPC-1 pancreatic ductal cell line indicated that gemcitabine prodrugs were more potent than their parent drug, gemcitabine. The transport and enzymatic profiles of 5'-D-valyl-gemcitabine and 5'-D-phenylalanyl-gemcitabine suggest their potential for increased oral uptake and delayed enzymatic bioconversion as well as enhanced uptake and cytotoxic activity in cancer cells, would facilitate the development of oral dosage form for anti-cancer agents and, hence, improve the quality of life for the cancer patients.
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Affiliation(s)
- Yasuhiro Tsume
- Department of Pharmaceutical Science, University of Michigan, Ann Arbor, MI, USA
| | - Tuba Incecayir
- Department of Pharmaceutical Technology, Gazi University, Etiler-Ankara, Turkey
| | | | | | - Gordon L Amidon
- Department of Pharmaceutical Science, University of Michigan, Ann Arbor, MI, USA.
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22
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Jensen JM, Simonsen FC, Mastali A, Hald H, Lillebro I, Diness F, Olsen L, Mirza O. Biophysical characterization of the proton-coupled oligopeptide transporter YjdL. Peptides 2012; 38:89-93. [PMID: 22940668 DOI: 10.1016/j.peptides.2012.08.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 08/15/2012] [Accepted: 08/16/2012] [Indexed: 01/31/2023]
Abstract
Proton-coupled oligopeptide transporters (POTs) utilize the electrochemical proton gradient to facilitate uptake of di- or tripeptide molecules. YjdL is one of four POTs found in Escherichia coli. It has shown an extraordinary preference for di- rather than tripeptides, and is therefore significantly different from prototypical POTs such as the human hPepT1. Nonetheless YjdL contains several highly conserved POT residues, which include Glu388 that is located in the putative substrate binding cavity. Here we present biophysical characterization of WT-YjdL and Glu388Gln. Isothermal titration calorimetrical studies exhibit a K(d) of 14 μM for binding of Ala-Lys to WT-YjdL. Expectedly, no binding could be detected for the tripeptide Ala-Ala-Lys. Surprisingly however, binding could not be detected for Ala-Gln, although earlier studies indicated inhibitory potencies of Ala-Gln to be comparable to Ala-Lys (IC(50) values of 0.6 compared to 0.3mM). Finally, Ala-Lys binding to Glu388Gln was also undetectable which may support a previously suggested role in interaction with the ligand peptide N-terminus.
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Affiliation(s)
- Johanne Mørch Jensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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23
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A POTluck of peptide transporters. EMBO J 2012; 31:3382-3. [PMID: 22842786 DOI: 10.1038/emboj.2012.206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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24
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Alternating access mechanism in the POT family of oligopeptide transporters. EMBO J 2012; 31:3411-21. [PMID: 22659829 PMCID: PMC3419923 DOI: 10.1038/emboj.2012.157] [Citation(s) in RCA: 163] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 05/03/2012] [Indexed: 01/16/2023] Open
Abstract
Proton-dependent oligopeptide transporters are required for the uptake of diet-derived peptides in all kingdoms of life. The crystal structure of a bacterial transporter in the inward open conformation, together with a published structure in an occluded conformation, reveals the peptide transport mechanism. Short chain peptides are actively transported across membranes as an efficient route for dietary protein absorption and for maintaining cellular homeostasis. In mammals, peptide transport occurs via PepT1 and PepT2, which belong to the proton-dependent oligopeptide transporter, or POT family. The recent crystal structure of a bacterial POT transporter confirmed that they belong to the major facilitator superfamily of secondary active transporters. Despite the functional characterization of POT family members in bacteria, fungi and mammals, a detailed model for peptide recognition and transport remains unavailable. In this study, we report the 3.3-Å resolution crystal structure and functional characterization of a POT family transporter from the bacterium Streptococcus thermophilus. Crystallized in an inward open conformation the structure identifies a hinge-like movement within the C-terminal half of the transporter that facilitates opening of an intracellular gate controlling access to a central peptide-binding site. Our associated functional data support a model for peptide transport that highlights the importance of salt bridge interactions in orchestrating alternating access within the POT family.
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25
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Potential of amino acid/dipeptide monoester prodrugs of floxuridine in facilitating enhanced delivery of active drug to interior sites of tumors: a two-tier monolayer in vitro study. Pharm Res 2011; 28:2575-88. [PMID: 21671137 DOI: 10.1007/s11095-011-0485-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Accepted: 05/16/2011] [Indexed: 10/18/2022]
Abstract
PURPOSE To evaluate the advantages of amino acid/dipeptide monoester prodrugs for cancer treatments by assessing the uptake and cytotoxic effects of floxuridine prodrugs in a secondary cancer cell monolayer following permeation across a primary cancer cell monolayer. METHODS The first Capan-2 monolayer was grown on membrane transwell inserts; the second monolayer was grown at the bottom of a plate. The permeation of floxuridine and its prodrugs across the first monolayer and the uptake and cell proliferation assay on secondary layer were sequentially determined. RESULTS All floxuridine prodrugs exhibited greater permeation across the first Capan-2 monolayer than the parent drug. The correlation between uptake and growth inhibition in the second monolayer with intact prodrug permeating the first monolayer suggests that permeability and enzymatic stability are essential for sustained action of prodrugs in deeper layers of tumors. The correlation of uptake and growth inhibition were vastly superior for dipeptide prodrugs to those obtained with mono amino acid prodrugs. CONCLUSIONS Although a tentative general overall correlation between intact prodrug and uptake or cytotoxic action was obtained, it appears that a mixture of floxuridine prodrugs with varying beneficial characteristics may be more effective in treating tumors.
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26
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Application of 13C stable isotope labeling liquid chromatography-multiple reaction monitoring-tandem mass spectrometry method for determining intact absorption of bioactive dipeptides in rats. Anal Biochem 2011; 414:109-16. [PMID: 21377441 DOI: 10.1016/j.ab.2011.02.037] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2010] [Revised: 02/21/2011] [Accepted: 02/24/2011] [Indexed: 11/22/2022]
Abstract
The liquid chromatography-multiple reaction monitoring-tandem mass spectrometry (LC-MRM-MS/MS) method using (13)C stable isotope-labeled dipeptides was newly developed to simultaneously determine the absorption of three antihypertensive peptides (Val-Tyr, Met-Tyr, and Leu-Tyr) into blood of spontaneously hypertensive rats in one run-in assay. After extracting (13)C-labeled peptides in blood sample with a C(18) cartridge, the extract was applied to a (13)C monoisotopic transition LC-MRM-MS/MS system with D-Val-Tyr included as internal standard. An excellent separation of each dipeptide in LC was achieved at the elution condition of 5-100% methanol in 0.1% formic acid at a flow rate of 0.25 ml/min. The (13)C-labeled peptides ionized by electron spray were detected in the positive ion mode within 15 min. The established method showed high reproducibility with less than 10% coefficient of variation as well as high accuracy of more than 85%. After the administration of a mixture containing the three (13)C-labeled dipeptides to rats at each dose of 30 mg/kg, we could successfully determine the intact absorption of each (13)C-labeled peptide with the maximal absorption amount of 1.1 ng/ml plasma for Val-Tyr by the proposed LC-MRM-MS/MS method.
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27
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Foley DW, Rajamanickam J, Bailey PD, Meredith D. Bioavailability through PepT1: the role of computer modelling in intelligent drug design. Curr Comput Aided Drug Des 2010; 6:68-78. [PMID: 20370696 DOI: 10.2174/157340910790980133] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In addition to being responsible for the majority of absorption of dietary nitrogen, the mammalian proton-coupled di- and tri-peptide transporter PepT1 is also recognised as a major route of drug delivery for several important classes of compound, including beta-lactam antibiotics and angiotensin-converting enzyme inhibitors. Thus there is considerable interest in the PepT1 protein and especially its substrate binding site. In the absence of a crystal structure, computer modelling has been used to try to understand the relationship between PepT1 3D structure and function. Two basic approaches have been taken: modelling the transporter protein, and modelling the substrate. For the former, computer modelling has evolved from early interpretations of the twelve transmembrane domain structure to more recent homology modelling based on recently crystallised bacterial members of the major facilitator superfamily (MFS). Substrate modelling has involved the proposal of a substrate binding template, to which all substrates must conform and from which the affinity of a substrate can be estimated relatively accurately, and identification of points of potential interaction of the substrate with the protein by developing a pharmacophore model of the substrates. Most recently, these two approaches have moved closer together, with the attempted docking of a substrate library onto a homology model of the human PepT1 protein. This article will review these two approaches in which computers have been applied to peptide transport and suggest how such computer modelling could affect drug design and delivery through PepT1.
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Affiliation(s)
- David W Foley
- Faculty of Natural Sciences, Keele University, Keele, Staffs ST5 5BG, UK
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28
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Brandsch M, Knütter I, Bosse-Doenecke E. Pharmaceutical and pharmacological importance of peptide transporters. J Pharm Pharmacol 2010; 60:543-85. [DOI: 10.1211/jpp.60.5.0002] [Citation(s) in RCA: 179] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
AbstractPeptide transport is currently a prominent topic in membrane research. The transport proteins involved are under intense investigation because of their physiological importance in protein absorption and also because peptide transporters are possible vehicles for drug delivery. Moreover, in many tissues peptide carriers transduce peptidic signals across membranes that are relevant in information processing. The focus of this review is on the pharmaceutical relevance of the human peptide transporters PEPT1 and PEPT2. In addition to their physiological substrates, both carriers transport many β-lactam antibiotics, valaciclovir and other drugs and prodrugs because of their sterical resemblance to di- and tripeptides. The primary structure, tissue distribution and substrate specificity of PEPT1 and PEPT2 have been well characterized. However, there is a dearth of knowledge on the substrate binding sites and the three-dimensional structure of these proteins. Until this pivotal information becomes available by X-ray crystallography, the development of new drug substrates relies on classical transport studies combined with molecular modelling. In more than thirty years of research, data on the interaction of well over 700 di- and tripeptides, amino acid and peptide derivatives, drugs and prodrugs with peptide transporters have been gathered. The aim of this review is to put the reports on peptide transporter-mediated drug uptake into perspective. We also review the current knowledge on pharmacogenomics and clinical relevance of human peptide transporters. Finally, the reader's attention is drawn to other known or proposed human peptide-transporting proteins.
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Affiliation(s)
- Matthias Brandsch
- Membrane Transport Group, Biozentrum of the Martin-Luther-University Halle-Wittenberg, D-06120 Halle, Germany
| | - Ilka Knütter
- Membrane Transport Group, Biozentrum of the Martin-Luther-University Halle-Wittenberg, D-06120 Halle, Germany
| | - Eva Bosse-Doenecke
- Institute of Biochemistry/Biotechnology, Faculty of Science I, Martin-Luther-University Halle-Wittenberg, D-06120 Halle, Germany
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29
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Kikuchi A, Tomoyasu T, Tanaka M, Kanamitsu K, Sasabe H, Maeda T, Odomi M, Tamai I. Peptide Derivation of Poorly Absorbable Drug Allows Intestinal Absorption Via Peptide Transporter. J Pharm Sci 2009; 98:1775-87. [DOI: 10.1002/jps.21551] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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30
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Foley D, Bailey P, Pieri M, Meredith D. Targeting ketone drugs towards transport by the intestinal peptide transporter, PepT1. Org Biomol Chem 2009; 7:1064-7. [PMID: 19262922 PMCID: PMC2898646 DOI: 10.1039/b818606e] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Accepted: 01/05/2009] [Indexed: 11/21/2022]
Abstract
Thiodipeptide prodrugs of the ketone nabumetone are shown to have affinity for, and be transported by, PepT1 in vitro.
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Affiliation(s)
- David Foley
- School of Chemistry, University of Manchester, Manchester, M13 9PL, UK.
| | - Patrick Bailey
- Faculty of Natural Sciences, Keele University, Keele, Staffordshire ST5 5BG, UK. ; Fax: +44 (0)1782 584593; Tel: +44 (0)1782 584583
| | - Myrtani Pieri
- School of Life Sciences, Oxford Brookes University, Headington, Oxford OX3 0BP, UK
| | - David Meredith
- School of Life Sciences, Oxford Brookes University, Headington, Oxford OX3 0BP, UK
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31
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Rubio-Aliaga I, Daniel H. Peptide transporters and their roles in physiological processes and drug disposition. Xenobiotica 2008; 38:1022-42. [PMID: 18668438 DOI: 10.1080/00498250701875254] [Citation(s) in RCA: 158] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
1. The peptide transporters belong to the peptide transporter (PTR) family and serve as integral membrane proteins for the cellular uptake of di- and tripeptides in the organism. By their ability also to transport peptidomimetics and other substrates with therapeutic activities or precursors of pharmacologically active agents, they are of considerable importance in pharmacology. 2. PEPT1 is the low-affinity, high-capacity transporter and is mainly expressed in the small intestine, whereas PEPT2 is the high-affinity, low-capacity transporter and has a broader distribution in the organism. 3. Targeted mouse models have revealed PEPT2 to be the dominant transporter for the reabsorption of di- and tripeptides and its pharmacological substrates in the organism, and for the removal of these substrates from the cerebrospinal fluid. Moreover, the peptide transporters undergo physiological and pharmacological regulation and, of great interest, are present in disease states where PEPT1 exhibits ectopic expression in colonic inflammation. 4. The paper reviews the structural characteristics of the peptide transporters, the structural requirements for substrates, the distribution of the peptide transporters in the organism, and finally their regulation in the organism in healthy and pathological situations.
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Affiliation(s)
- I Rubio-Aliaga
- Molecular Nutrition Unit, Technical University of Munich, Freising-Weihenstephan, Germany
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Tsume Y, Hilfinger JM, Amidon GL. Enhanced cancer cell growth inhibition by dipeptide prodrugs of floxuridine: increased transporter affinity and metabolic stability. Mol Pharm 2008; 5:717-27. [PMID: 18652477 PMCID: PMC2659690 DOI: 10.1021/mp800008c] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Dipeptide monoester prodrugs of floxuridine were synthesized, and their chemical stability in buffers, resistance to glycosidic bond metabolism, affinity for PEPT1, enzymatic activation and permeability in cancer cells were determined and compared to those of mono amino acid monoester floxuridine prodrugs. Prodrugs containing glycyl moieties were the least stable in pH 7.4 buffer ( t 1/2 < 100 min). The activation of all floxuridine prodrugs was 2- to 30-fold faster in cell homogenates than their hydrolysis in buffer, suggesting enzymatic action. The enzymatic activation of dipeptide monoester prodrugs containing aromatic promoieties in cell homogenates was 5- to 20-fold slower than that of other dipeptide and most mono amino acid monoester prodrugs ( t 1/2 approximately 40 to 100 min). All prodrugs exhibited enhanced resistance to glycosidic bond metabolism by thymidine phosphorylase compared to parent floxuridine. In general, the 5'-O-dipeptide monoester floxuridine prodrugs exhibited higher affinity for PEPT1 than the corresponding 5'-O-mono amino acid ester prodrugs. The permeability of dipeptide monoester prodrugs across Caco-2 and Capan-2 monolayers was 2- to 4-fold higher than the corresponding mono amino acid ester prodrug. Cell proliferation assays in AsPC-1 and Capan-2 pancreatic ductal cell lines indicated that the dipeptide monoester prodrugs were equally as potent as mono amino acid prodrugs. The transport and enzymatic profiles of 5'- l-phenylalanyl- l-tyrosyl-floxuridine, 5'- l-phenylalanyl- l-glycyl-floxuridine, and 5'- l-isoleucyl- l-glycyl-floxuridine suggest their potential for increased oral uptake, delayed enzymatic bioconversion and enhanced resistance to metabolism to 5-fluorouracil, as well as enhanced uptake and cytotoxic activity in cancer cells, attributes that would facilitate prolonged systemic circulation for enhanced therapeutic action.
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Affiliation(s)
- Yasuhiro Tsume
- Department of Pharmaceutical Science, University of Michigan, Ann Arbor, Michigan 48109, USA
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Tsume Y, Vig BS, Sun J, Landowski CP, Hilfinger JM, Ramachandran C, Amidon GL. Enhanced absorption and growth inhibition with amino acid monoester prodrugs of floxuridine by targeting hPEPT1 transporters. Molecules 2008; 13:1441-54. [PMID: 18719516 PMCID: PMC6244841 DOI: 10.3390/molecules13071441] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2008] [Accepted: 06/27/2008] [Indexed: 11/16/2022] Open
Abstract
A series of amino acid monoester prodrugs of floxuridine was synthesized and evaluated for the improvement of oral bioavailability and the feasibility of target drug delivery via oligopeptide transporters. All floxuridine 5'-amino acid monoester prodrugs exhibited PEPT1 affinity, with inhibition coefficients of Gly-Sar uptake (IC50) ranging from 0.7 - 2.3 mM in Caco-2 and 2.0 - 4.8 mM in AsPC-1 cells, while that of floxuridine was 7.3 mM and 6.3 mM, respectively. Caco-2 membrane permeabilities of floxuridine prodrugs (1.01 - 5.31 x 10(-6 )cm/sec) and floxuridine (0.48 x 10(-6 )cm/sec) were much higher than that of 5-FU (0.038 x 10(-6) cm/sec). MDCK cells stably transfected with the human oligopeptide transporter PEPT1 (MDCK/hPEPT1) exhibited enhanced cell growth inhibition in the presence of the prodrugs. This prodrug strategy offers great potential, not only for increased drug absorption but also for improved tumor selectivity and drug efficacy.
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Affiliation(s)
- Yasuhiro Tsume
- Department of Pharmaceutical Science, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, MI 48109-1065, USA; E-mails: ;
| | - Balvinder S. Vig
- Pharmaceutical Research Institute, Bristol-Myers Squibb Company, New Brunswick, NJ 08502; E-mail:
| | - Jing Sun
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA;
| | - Christopher P. Landowski
- Institute of Biochemistry and Molecular Medicine, University of Bern, CH-3012 Bern, Switzerland;
| | | | - Chandrasekharan Ramachandran
- Department of Pharmaceutical Science, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, MI 48109-1065, USA; E-mails: ;
| | - Gordon L Amidon
- Department of Pharmaceutical Science, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, MI 48109-1065, USA; E-mails: ;
- Author to whom correspondence should be addressed; E-mail:E-mail Phone: +1-734-764-2440; Fax: +1-734-763-6423
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34
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Zhu XL, Watanabe K, Shiraishi K, Ueki T, Noda Y, Matsui T, Matsumoto K. Identification of ACE-inhibitory peptides in salt-free soy sauce that are transportable across caco-2 cell monolayers. Peptides 2008; 29:338-44. [PMID: 18160180 DOI: 10.1016/j.peptides.2007.11.006] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2007] [Revised: 11/07/2007] [Accepted: 11/08/2007] [Indexed: 11/27/2022]
Abstract
In present study, we aimed to identify angiotensin I-converting enzyme (ACE)-inhibitory peptides from a salt-free soy sauce (SFS), a newly developed antihypertensive seasoning obtained by Aspergillus oryzae fermentation of soybean in the absence of salt, which can be transported through caco-2 cell monolayers. Through an Ussing transport investigation of SFS across caco-2 cell monolayers, three di-peptides, Ala-Phe, Phe-Ile and Ile-Phe, were successfully identified from the SFS as transportable inhibitory peptides. Ala-Phe and Ile-Phe, but not Phe-Ile, exhibited ACE-inhibitory activity with IC(50) values of 165.3 microM and 65.8 microM, respectively. Kinetic studies revealed that Ile-Phe (Km: 3.1 mM, P(app): 2.4 x 10(-6) cm/s) exhibited greater affinity toward the transport compared with Ala-Phe (K(m): 48.1 mM, P(app): 1.4 x 10(-6) cm/s) and Phe-Ile (K(m): 12.7 mM, P(app): 1.4 x 10(-6) cm/s).
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Affiliation(s)
- Xiao-Lin Zhu
- Division of Bioscience and Bioenvironmental Sciences, Faculty of Agriculture, Graduate School of Kyushu University, Fukuoka, Japan
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Li F, Maag H, Alfredson T. Prodrugs of nucleoside analogues for improved oral absorption and tissue targeting. J Pharm Sci 2008; 97:1109-34. [PMID: 17696166 DOI: 10.1002/jps.21047] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Nucleoside analogues are widely used for the treatment of antiviral infections and anticancer chemotherapy. However, many nucleoside analogues suffer from poor oral bioavailability due to their high polarity and low intestinal permeability. In order to improve oral absorption of these polar drugs, prodrugs have been employed to increase lipophilicity by chemical modification of the parent. Alternatively, prodrugs targeting transporters present in the intestine have been exploited to facilitate the transport of the nucleoside analogues. Valacyclovir and valganciclovir are two successful valine ester prodrugs transported by the PepT1 transporter. Recently, research efforts have focused on design of prodrugs for tissue specific delivery to improve efficacy and safety. This review presents advances of prodrug approaches for improved oral absorption of nucleoside analogues and recent developments in tissue targeting.
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Affiliation(s)
- Fujun Li
- Department of Pharmaceutics, Roche Palo Alto LLC, 3431 Hillview Avenue, Palo Alto, CA 94304, USA.
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36
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Evaluation of pancreatic exocrine secretion using 13C-dipeptide (benzoyl-L-tyrosyl-[1-(13)C]alanine) breath test: focusing on pancreatoduodenectomy cases. Pancreas 2007; 35:313-9. [PMID: 18090236 DOI: 10.1097/mpa.0b013e31812507a7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVES We investigated whether a breath test using benzoyl-L-tyrosyl-[1-(13)C]alanine (Bz-Tyr-Ala) allows assessment of pancreatic exocrine function. METHODS Benzoyl-L-tyrosyl-[1-(13)C]alanine was orally administered, and changes in (13)CO2 were expressed as delta per thousand. The breath test was performed in chronic pancreatitis patients and healthy subjects in a preliminary study and, subsequently, in 17 pancreatoduodenectomy patients, to examine the difference between the results obtained at the times of pancreatic tube insertion and removal, the relationship between breath test results after tube removal and the volume of pancreatic juice drained, and the difference in results between the presence versus the absence of histological changes of chronic pancreatitis. RESULTS The delta per thousand was lower in the chronic pancreatitis patients than in healthy subjects. In the postoperative patients, the delta per thousand was higher at tube insertion than at tube removal. The correlations of the delta per thousand with the maximum volume of pancreatic juice, its mean volume, and pancreatic juice amylase levels were 0.865, 0.757, and 0.853, respectively. The delta per thousand was lower in 11 patients with that in 6 patients without histological changes of chronic pancreatitis. CONCLUSIONS These results suggest that the Bz-Tyr-Ala breath test can measure pancreatic exocrine function.
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Zhu XL, Matsui T, Watanabe K, Shiraishi K, Ueki T, Matsumoto K. Simultaneous determination of Angiotensin I-converting enzyme inhibitory peptides in tryptic casein hydrolysate by high-performance liquid chromatography combined with a replicate heart-cut column-switching technique. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2007; 55:8367-8371. [PMID: 17927145 DOI: 10.1021/jf0720584] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
A replicate heart-cut column-switching HPLC method combined with two switching valves was newly developed for the simultaneous determination of three antihypertensive peptides (Ala-Phe, Tyr-Pro, and Trp-Tyr) in tryptic casein hydrolysate in one run-in assay. After a first separation on an octadecyl silane (ODS) column, heart-cuts of each peptide were individually separated on a subsequent analytical ODS column: 26% acetonitrile for Ala-Phe and Tyr-Pro (32% for Trp-Tyr) in 0.1% trifluoroacetic acid containing 10 mM sodium 1-octanesulfonate at 0.8 mL/min. Ala-Phe, Tyr-Pro, and Trp-Tyr in casein hydrolysate were determined within 70 min to be 0.377 +/- 0.037 mg/g, 2.50 +/- 0.26 mg/g, and 0.096 +/- 0.008 mg/g, respectively.
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Affiliation(s)
- Xiao-Lin Zhu
- Division of Bioscience and Bioenvironmental Sciences, Faculty of Agriculture, Graduate School of Kyushu University, 6-10-1 Hakozaki, Fukuoka 812-8581, Japan
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Pieri M, Hall D, Price R, Bailey P, Meredith D. Site-directed mutagenesis of Arginine282 suggests how protons and peptides are co-transported by rabbit PepT1. Int J Biochem Cell Biol 2007; 40:721-30. [PMID: 18037334 PMCID: PMC2267855 DOI: 10.1016/j.biocel.2007.10.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2007] [Revised: 10/09/2007] [Accepted: 10/09/2007] [Indexed: 11/02/2022]
Abstract
The mammalian proton-coupled peptide transporter PepT1 is the major route of uptake for dietary nitrogen, as well as the oral absorption of a number of drugs, including beta-lactam antibiotics and angiotensin-converting enzyme inhibitors. Here we have used site-directed mutagenesis to investigate further the role of conserved charged residues in transmembrane domains. Mutation of rabbit PepT1 arginine282 (R282, transmembrane domain 7) to a positive (R282K) or physiologically titratable residue (R282H), resulted in a transporter with wild-type characteristics when expressed in Xenopus laevis oocytes. Neutral (R282A, R282Q) or negatively charged (R282D, R282E) substitutions gave a transporter that was not stimulated by external acidification (reducing pH(out) from 7.4 to 5.5) but transported at the same rate as the wild-type maximal rate (pH(out) 5.5); however, only the R282E mutation was unable to concentrate substrate above the extracellular level. All of the R282 mutants showed trans-stimulation of efflux comparable to the wild-type, except R282E-PepT1 which was faster. A conserved negatively charged residue, aspartate341 (D341) in transmembrane domain 8 was implicated in forming a charge pair with R282, as R282E/D341R- and R282D/D341R-PepT1 had wild-type transporter characteristics. Despite their differences in ability to accumulate substrate, both R282E- and R282D-PepT1 showed an increased charge:peptide stoichiometry over the wild-type 1:1 ratio for the neutral dipeptide Gly-l-Gln, measured using two-electrode voltage clamp. This extra charge movement was linked to substrate transport, as 4-aminobenzoic acid, which binds but is not translocated, did not induce membrane potential depolarisation in R282E-expressing oocytes. A model is proposed for the substrate binding/translocation process in PepT1.
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Affiliation(s)
- Myrtani Pieri
- Department of Physiology, Anatomy & Genetics, University of Oxford, Oxford OX1 3QX, UK
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39
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Kohno T, Ito A, Hosoi I, Hirayama J, Shibata K. Synthetic 13C-dipeptide breath test for the rapid assessment of pancreatic exocrine insufficiency in rats. Scand J Gastroenterol 2007; 42:992-9. [PMID: 17613930 DOI: 10.1080/00365520601155472] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE (13)C-breath tests have been investigated in order to assess pancreatic exocrine function using various (13)C-compounds, but they have not been accepted for routine clinical use. One of the barriers to their acceptance is that these tests are time-consuming and require up to several hours for breath collection. The purpose of this study was to design a novel (13)C-compound that would make a rapid (13)C-breath test for assessing exocrine pancreatic function possible. MATERIAL AND METHODS N-benzoyl-L-tyrosyl-1-(13)C-L-alanine was synthesized, and the characteristics of its cleavage in duodenal juice and in the duodenum of rats were examined. Thereafter, a (13)C-breath test was carried out in which N-benzoyl-L-tyrosyl-1-(13)C-L-alanine was given orally to pancreatic exocrine-insufficient and normal control rats. RESULTS N-benzoyl-L-tyrosyl-1-(13)C-L-alanine was readily cleaved and liberated 1-(13)C-L-alanine in the duodenal juice. Carboxypeptidase was a major contributor to the cleavage. When N-benzoyl-L-tyrosyl-1-(13)C-L-alanine was injected into the duodenum and orally administered to the rats, the (13)C atom% of CO(2) in breath increased rapidly. This indicated that N-benzoyl-L-tyrosyl-1-(13)C-L-alanine in the duodenum liberated (13)C-Ala on cleavage. (13)C-Ala is absorbed and metabolized to liberate (13)CO(2), which is exhaled. It was shown that the Delta(13)CO(2) ( per thousand) in the N-benzoyl-L-tyrosyl-1-(13)C-L-alanine breath test in the pancreatic exocrine-insufficient rats, in whom the absorption and metabolism of (13)C-Ala was unimpaired, was significantly lower than that in the control rats. CONCLUSIONS The rate of increase in the Delta(13)CO(2) ( per thousand) in the N-benzoyl-L-tyrosyl-1-(13)C-L-alanine breath test is expected to be proportional to the rate of N-benzoyl-L-tyrosyl-1-(13)C-L-alanine cleavage by pancreatic proteases in the duodenum. We propose the N-benzoyl-L-tyrosyl-1-(13)C-L-alanine breath test as a rapid test for assessing pancreatic exocrine function.
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Affiliation(s)
- Tadashi Kohno
- Fundamental Technology Department, Tokyo Gas Co. Ltd., Tokyo, Japan
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Kamphorst J, Cucurull-Sanchez L, Jones B. A performance evaluation of multiple classification models of human PEPT1 inhibitors and non-inhibitors. ACTA ACUST UNITED AC 2007. [DOI: 10.1002/qsar.200630025] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Matsui T, Zhu XL, Watanabe K, Tanaka K, Kusano Y, Matsumoto K. Combined administration of captopril with an antihypertensive Val–Tyr di-peptide to spontaneously hypertensive rats attenuates the blood pressure lowering effect. Life Sci 2006; 79:2492-8. [PMID: 16959271 DOI: 10.1016/j.lfs.2006.08.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2006] [Revised: 08/05/2006] [Accepted: 08/15/2006] [Indexed: 11/28/2022]
Abstract
Some di-peptides have been proven to exert an antihypertensive effect in mild-hypertensive subjects. The aim of this study was to clarify whether combined administration of an ACE inhibitor, captopril, with an antihypertensive di-peptide Val-Tyr (VY) would alter their potent antihypertensive effects in spontaneously hypertensive rats (SHRs). Single oral administration of captopril (2.5 mg/kg), VY (25 mg/kg), or captopril (2.5 mg/kg)+VY (25 mg/kg) to 18-week-old male SHRs was performed. Systolic blood pressure (SBP) was measured up to 9 h, and plasma captopril concentrations were determined. A transport study of captopril and/or VY across living rat jejunum from SHRs was also performed to evaluate the kinetics of absorption. Combined administration of captopril with VY failed to lower the BP during the 9-h experiment. A transport study of captopril or VY revealed that VY inhibited captopril transport, and vice versa, in a competitive manner and exhibited an approximately 1/3-fold lower Ki value for captopril compared with that for VY; indicating that both compounds compete for the same membrane transport pathway. A 50% decrease in plasma captopril levels by combined administration with VY supported that the attenuation of the BP lowering effect was due to inhibition of captopril uptake by VY. Consequently, our findings suggest that subjects treated with ACE inhibitors for hypertension should avoid combined-intake with antihypertensive foods that are rich in small peptides due to the competitive inhibition of drug uptake by these peptides.
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Affiliation(s)
- Toshiro Matsui
- Division of Bioscience and Bioenvironmental Sciences, Faculty of Agriculture, Graduate School of Kyushu University, Fukuoka 812-8581, Japan.
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Balakrishnan A, Polli JE. Apical sodium dependent bile acid transporter (ASBT, SLC10A2): a potential prodrug target. Mol Pharm 2006; 3:223-30. [PMID: 16749855 PMCID: PMC2796132 DOI: 10.1021/mp060022d] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
A major hurdle impeding the successful clinical development of drug candidates can be poor intestinal permeability. Low intestinal permeability may be enhanced by a prodrug approach targeting membrane transporters in the small intestine. Transporter specificity, affinity, and capacity are three factors in targeted prodrug design. The human apical sodium dependent bile acid transporter (SLC10A2) belongs to the solute carrier family (SLC) of transporters and is an important carrier protein expressed in the small intestine. In spite of its appearing to be an excellent target for prodrug design, few studies have targeted human apical sodium dependent bile acid transporter (hASBT) to improve oral bioavailability. This review discusses bile acids including their chemistry and their absorptive disposition. Additionally, hASBT-mediated prodrug targeting is discussed, including QSAR, in vitro models for hASBT assay, and the current progress in utilizing hASBT as a drug delivery target.
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Affiliation(s)
- Anand Balakrishnan
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD 21201
| | - James E. Polli
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD 21201
- Author to whom, correspondence should be addressed, James E. Polli, Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, HSF2, room 623, Baltimore, MD 21201, Telephone: 410-706-8292, Fax : 410-706-5017,
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Vig BS, Stouch TR, Timoszyk JK, Quan Y, Wall DA, Smith RL, Faria TN. Human PEPT1 Pharmacophore Distinguishes between Dipeptide Transport and Binding. J Med Chem 2006; 49:3636-44. [PMID: 16759105 DOI: 10.1021/jm0511029] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The human intestinal oligopeptide transporter (PEPT1) facilitates the absorption of dipeptides, tripeptides, and many peptidomimetic drugs. In this study, a large number of peptides were selected to investigate the structural features required for PEPT1 transport. Binding affinity was determined in a Gly-Sar uptake inhibition assay, whereas functional transport was ranked in a membrane depolarization assay. Although most of the peptides tested could bind to PEPT1, not all were substrates. As expected, single amino acids and tetrapeptides could not bind to or be transported by PEPT1. Dipeptide transport was influenced by charge, hydrophobicity, size, and side chain flexibility. The extent of transport was variable, and unexpectedly, some dipeptides were not substrates of PEPT1. These included dipeptides with two positive charges or extreme bulk in either position 1 or 2. Our results identify key features required for PEPT1 transport in contrast to most previously described pharmacophores, which are based on the inhibition of transport of a known substrate.
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Affiliation(s)
- Balvinder S Vig
- Exploratory Biopharmaceutics and Stability, and Macromolecular Structure/CADD, Pharmaceutical Research Institute, Bristol-Myers Squibb Company, New Brunswick, New Jersey 08903-0191, USA
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Bailey PD, Boyd CAR, Collier ID, George JP, Kellett GL, Meredith D, Morgan KM, Pettecrew R, Price RA. Affinity prediction for substrates of the peptide transporter PepT1. Chem Commun (Camb) 2005:323-5. [PMID: 16391748 DOI: 10.1039/b511996k] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A quantitative method has been developed for determining the affinity of substrates for the peptide transporter PepT1, allowing oral availability of drugs via PepT1 to be estimated.
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Affiliation(s)
- Patrick D Bailey
- School of Chemistry, Faraday Building, University of Manchester, Sackville Street, Manchester, UK M60 1QD.
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45
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Våbenø J, Nielsen CU, Steffansen B, Lejon T, Sylte I, Jørgensen FS, Luthman K. Conformational restrictions in ligand binding to the human intestinal di-/tripeptide transporter: implications for design of hPEPT1 targeted prodrugs. Bioorg Med Chem 2005; 13:1977-88. [PMID: 15727852 DOI: 10.1016/j.bmc.2005.01.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2004] [Revised: 01/05/2005] [Accepted: 01/12/2005] [Indexed: 11/16/2022]
Abstract
The aim of the present study was to develop a computational method aiding the design of dipeptidomimetic pro-moieties targeting the human intestinal di-/tripeptide transporter hPEPT1. First, the conformation in which substrates bind to hPEPT1 (the bioactive conformation) was identified by conformational analysis and 2D dihedral driving analysis of 15 hPEPT1 substrates, which suggested that psi(1) approximately 165 degrees , omega(1) approximately 180 degrees , and phi(2) approximately 280 degrees were descriptive of the bioactive conformation. Subsequently, the conformational energy required to change the peptide backbone conformation (DeltaE(bbone)) from the global energy minimum conformation to the identified bioactive conformation was calculated for 20 hPEPT1 targeted model prodrugs with known K(i) values. Quantitatively, an inverse linear relationship (r(2)=0.81, q(2)=0.80) was obtained between DeltaE(bbone) and log1/K(i), showing that DeltaE(bbone) contributes significantly to the experimentally observed affinity for hPEPT1 ligands. Qualitatively, the results revealed that compounds classified as high affinity ligands (K(i)<0.5 mM) all have a calculated DeltaE(bbone)<1 kcal/mol, whereas medium and low-affinity compounds (0.5 mM<K(i)<15 mM) have DeltaE(bbone) values in the range 1-3 kcal/mol. The findings also shed new light on the basis for the experimentally observed stereoselectivity of hPEPT1.
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Affiliation(s)
- Jon Våbenø
- Department of Medicinal Chemistry, Institute of Pharmacy, University of Tromsø, N-9037 Tromsø, Norway
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46
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Nielsen CU, Våbenø J, Andersen R, Brodin B, Steffansen B. Recent advances in therapeutic applications of human peptide transporters. Expert Opin Ther Pat 2005. [DOI: 10.1517/13543776.15.2.153] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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47
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Nielsen CU, Brodin B, Jørgensen FS, Frokjaer S, Steffansen B. Human peptide transporters: therapeutic applications. Expert Opin Ther Pat 2005. [DOI: 10.1517/13543776.12.9.1329] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Uchiyama T, Kulkarni AA, Davies DL, Lee VHL. Biophysical evidence for His57 as a proton-binding site in the mammalian intestinal transporter hPepT1. Pharm Res 2004; 20:1911-6. [PMID: 14725353 DOI: 10.1023/b:pham.0000008036.05892.e9] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
PURPOSE The objective of this study was to provide direct evidence of the relative importance of the His57 residue present in transmembrane domain 2 (TMD 2) and the His121 residue in TMD 4 as proton-binding sites in human PepT1 (hPepT1) by using a novel mutagenesis approach. METHODS His57 and His121 in hPepT1 were each mutated to alanine, arginine, or lysine individually to obtain H57A-, H57R-, H57K-, H121A-, H121R-, and H121K-hPepT1. H7A-hPepT1 was used as a negative control. [3H]Glycylsarcosine (Gly-Sar) uptake was measured 72 h posttransfection using HEK293 cells individually transfected with these mutated proteins. Steady-state I/V curves (-150 mV to +50 mV, holding potential -70 mV) were obtained by measuring 5 mM Gly-Sar-induced currents in oocytes expressing H-57R- and H57K-hPepT1. Noninjected oocytes and wild-type hPepT1 (WT-hPepT1)-injected oocytes served as negative and positive controls, respectively. RESULTS At pH 6.0, H57K-, H57R-, H121K-, and H121R-hPepT1 led to a 97%, 90%, 45%, and 75% decrease in [3H]Gly-Sar uptake into HEK293 cells, respectively. At pH 7.4, uptake in cells transfected with H57K- and H57R-hPepT1 was not significantly different from that at pH 6.0, whereas cells expressing H121R- and H121K-hPepT1 showed 56% and 65% decrease, respectively, compared to that at pH 6.0. In oocytes expressing H57R-hPepT1, steady-state currents induced by 5 mM Gly-Sar increased with increasing pH (I(max) = 300 nA at pH 8.5), suggesting the binding of protons to H57R. No such trend was observed in oocytes injected with H57K, H121R, and H121K cRNA. CONCLUSIONS H57R-hPepT1 is able to bind protons at a relatively basic pH, resulting in facilitation of transport of Gly-Sar by hPepT1 at higher pH. Our novel approach provides direct evidence that His57 is a principal proton-binding site in hPepT1.
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Affiliation(s)
- Tomomi Uchiyama
- Department of Pharmaceutical Sciences, University of Southern California, 1985 Zonal Ave., Los Angeles, CA 90089-9121, USA
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Brandsch M, Knütter I, Leibach FH. The intestinal H+/peptide symporter PEPT1: structure–affinity relationships. Eur J Pharm Sci 2004; 21:53-60. [PMID: 14706811 DOI: 10.1016/s0928-0987(03)00142-8] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Peptide transporter 1, PEPT1, of the mammalian enterocyte is presently under intense investigation in many laboratories because of its nutritional importance in the absorption of protein hydrolysis products and because more recent studies have shown that many drugs and prodrugs gain entry into the systemic circulation via PEPT1. Until the exact structural features of the substrate binding site of PEPT1 become available, for example by X-ray crystallography, determination of affinities followed by proof of actual membrane translocation will have to suffice when testing for possible new substrates for PEPT1. Affinity constants reflect the strength of their interaction with the binding site of the transporter. A review of the literature shows a wide range of affinity constants between 2 microM and 30 mM. We consider affinity constants for substrates or inhibitors of PEPT1 lower than 0.5 mM as high affinity, between 0.5 and 5.0 mM as medium affinity and above 5 mM as low affinity. Values above 15 mM we consider with great caution. In this mini-review we discuss affinities and structural determinants which affect affinities of a variety of substrates for PEPT1.
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Affiliation(s)
- Matthias Brandsch
- Membrane Transport Group, Biozentrum of Martin-Luther-University Halle-Wittenberg, Weinbergweg 22, D-06120 Halle, Germany.
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