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Li R, Mak WWS, Li J, Zheng C, Shiu PHT, Seto SW, Lee SMY, Leung GPH. Structure-Activity Relationship Studies of 4-((4-(2-fluorophenyl)piperazin-1-yl)methyl)-6-imino-N-(naphthalen-2-yl)-1,3,5-triazin-2-amine (FPMINT) Analogues as Inhibitors of Human Equilibrative Nucleoside Transporters. Front Pharmacol 2022; 13:837555. [PMID: 35264969 PMCID: PMC8899516 DOI: 10.3389/fphar.2022.837555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 01/27/2022] [Indexed: 11/13/2022] Open
Abstract
Equilibrative nucleoside transporters (ENTs) play a vital role in nucleotide synthesis, regulation of adenosine function and chemotherapy. Current inhibitors of ENTs are mostly ENT1-selective. Our previous study has demonstrated that 4-((4-(2-fluorophenyl)piperazin-1-yl)methyl)-6-imino-N-(naphthalen-2-yl)-1,3,5-triazin-2-amine (FPMINT) is a novel inhibitor of ENTs, which is more selective to ENT2 than to ENT1. The present study aimed to screen a series of FPMINT analogues and study their structure-activity relationship. Nucleoside transporter-deficient cells transfected with cloned human ENT1 and ENT2 were used as in vitro models. The results of the [3H]uridine uptake study showed that the replacement of the naphthalene moiety with the benzene moiety could abolish the inhibitory effects on ENT1 and ENT2. The addition of chloride to the meta position of this benzene moiety could restore only the inhibitory effect on ENT1 but had no effect on ENT2. However, the addition of the methyl group to the meta position or the ethyl or oxymethyl group to the para position of this benzene moiety could regain the inhibitory activity on both ENT1 and ENT2. The presence of a halogen substitute, regardless of the position, in the fluorophenyl moiety next to the piperazine ring was essential for the inhibitory effects on ENT1 and ENT2. Among the analogues tested, compound 3c was the most potent inhibitor. Compound 3c reduced V max of [3H]uridine uptake in ENT1 and ENT2 without affecting K m. The inhibitory effect of compound 3c could not be washed out. Compound 3c did not affect cell viability, protein expression and internalization of ENT1 and ENT2. Therefore, similar to FPMINT, compound 3c was an irreversible and non-competitive inhibitor. Molecular docking analysis also showed that the binding site of compound 3c in ENT1 may be different from that of other conventional inhibitors. It is expected that structural modification may further improve its potency and selectivity and lead to the development of useful pharmacological agents.
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Affiliation(s)
- Renkai Li
- Department of Pharmacology and Pharmacy, University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Winston Wing-Shum Mak
- Department of Pharmacology and Pharmacy, University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Jingjing Li
- Department of Pharmacology and Pharmacy, University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Chengwen Zheng
- Department of Pharmacology and Pharmacy, University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Polly Ho-Ting Shiu
- Department of Pharmacology and Pharmacy, University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Sai-Wang Seto
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China
| | - Simon Ming-Yuen Lee
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Avenida da Universidade, Taipa, China
| | - George Pak-Heng Leung
- Department of Pharmacology and Pharmacy, University of Hong Kong, Pokfulam, Hong Kong SAR, China
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Rehan S, Shahid S, Salminen TA, Jaakola VP, Paavilainen VO. Current Progress on Equilibrative Nucleoside Transporter Function and Inhibitor Design. SLAS DISCOVERY 2019; 24:953-968. [PMID: 31503511 DOI: 10.1177/2472555219870123] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Physiological nucleosides are used for the synthesis of DNA, RNA, and ATP in the cell and serve as universal mammalian signaling molecules that regulate physiological processes such as vasodilation and platelet aggregation by engaging with cell surface receptors. The same pathways that allow uptake of physiological nucleosides mediate the cellular import of synthetic nucleoside analogs used against cancer, HIV, and other viral diseases. Physiological nucleosides and nucleoside drugs are imported by two families of nucleoside transporters: the SLC28 concentrative nucleoside transporters (CNTs) and SLC29 equilibrative nucleoside transporters (ENTs). The four human ENT paralogs are expressed in distinct tissues, localize to different subcellular sites, and transport a variety of different molecules. Here we provide an overview of the known structure-function relationships of the ENT family with a focus on ligand binding and transport in the context of a new hENT1 homology model. We provide a generic residue numbering system for the different ENTs to facilitate the interpretation of mutational data produced using different ENT homologs. The discovery of paralog-selective small-molecule modulators is highly relevant for the design of new therapies and for uncovering the functions of poorly characterized ENT family members. Here, we discuss recent developments in the discovery of new paralog-selective small-molecule ENT inhibitors, including new natural product-inspired compounds. Recent progress in the ability to heterologously produce functional ENTs will allow us to gain insight into the structure and functions of different ENT family members as well as the rational discovery of highly selective inhibitors.
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Affiliation(s)
- Shahid Rehan
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland.,HiLIFE, University of Helsinki, Helsinki, Finland
| | - Saman Shahid
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Tiina A Salminen
- Structural Bioinformatics Laboratory, Biochemistry, Faculty of Science and Engineering, Åbo Akademi University, Turku, Finland
| | - Veli-Pekka Jaakola
- Chemical Biology & Therapeutics, Novartis Institutes for BioMedical Research, Novartis Pharma AG, Basel, Switzerland
| | - Ville O Paavilainen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland.,HiLIFE, University of Helsinki, Helsinki, Finland
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Tang PCT, Yang C, Li RWS, Lee SMY, Hoi MPM, Chan SW, Kwan YW, Tse CM, Leung GPH. Inhibition of human equilibrative nucleoside transporters by 4-((4-(2-fluorophenyl)piperazin-1-yl)methyl)-6-imino-N-(naphthalen-2-yl)-1,3,5-triazin-2-amine. Eur J Pharmacol 2016; 791:544-551. [PMID: 27388143 DOI: 10.1016/j.ejphar.2016.07.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 06/24/2016] [Accepted: 07/04/2016] [Indexed: 01/07/2023]
Abstract
Equilibrative nucleoside transporters (ENTs) play a crucial role in the transport of nucleoside and nucleoside analogues, which are important for nucleotide synthesis and chemotherapy. In addition, ENTs regulate extracellular adenosine levels in the vicinity of its receptors and hence influence adenosine-related functions. The clinical applications of ENT inhibitors in the treatment of cardiovascular diseases and cancer therapy have been explored in numerous studies. However, all ENT inhibitors to date are selective for ENT1 but not ENT2. In the present study, we investigated the novel compound 4-((4-(2-fluorophenyl)piperazin-1-yl)methyl)-6-imino-N-(naphthalen-2-yl)-1,3,5-triazin-2-amine (FPMINT) as an inhibitor of ENT1 and ENT2. Nucleoside transporter-deficient PK15NTD cells stably expressing ENT1 and ENT2 showed that FPMINT inhibited [3H]uridine and [3H]adenosine transport through both ENT1 and ENT2 in a concentration-dependent manner. The IC50 value of FPMINT for ENT2 was 5-10-fold less than for ENT1, and FPMINT could not be displaced with excess washing. Kinetic studies revealed that FPMINT reduced Vmax of [3H]uridine transport in ENT1 and ENT2 without affecting KM. Therefore, we conclude that FPMINT inhibits ENTs in an irreversible and non-competitive manner. Although already selective for ENT2 over ENT1, further modification of the chemical structure of FPMINT may lead to even better ENT2-selective inhibitors of potential clinical, physiological and pharmacological importance.
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Affiliation(s)
- Philip C T Tang
- Department of Pharmacology and Pharmacy, The University of Hong Kong, Hong Kong, China
| | - Cui Yang
- Ethnic Drug Screening & Pharmacology Center, Key Laboratory of Chemistry in Ethnic Medicinal Resources, State Ethnic Affairs Commission & Ministry of Education, Yunnan Minzu University, Kunming 650500, China
| | - Rachel Wai-Sum Li
- Department of Pharmacology and Pharmacy, The University of Hong Kong, Hong Kong, China
| | | | - Maggie Pui-Man Hoi
- Institute of Chinese Medical Sciences, University of Macau, Macao, China
| | - Shun-Wan Chan
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China
| | - Yiu-Wa Kwan
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Chung-Ming Tse
- Department of Medicine, Division of Gastroenterology, School of Medicine, The Johns Hopkins University, United States
| | - George Pak-Heng Leung
- Department of Pharmacology and Pharmacy, The University of Hong Kong, Hong Kong, China.
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Tlatelpa PC, Huang H. Stability of pyrimidine N-glycosydic bonds in the presence of Lawesson’s reagents: revisit of 2-thiolation of pyrimidine nucleosides. Tetrahedron Lett 2014. [DOI: 10.1016/j.tetlet.2014.06.089] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Nucleoside transporters: biological insights and therapeutic applications. Future Med Chem 2012; 4:1461-78. [DOI: 10.4155/fmc.12.79] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Nucleoside transporters play important physiological roles by regulating intra- and extra-cellular concentrations of purine and pyrimidine (deoxy)nucleosides. This review describes the biological function and activity of the two major families of membrane nucleoside transporters that exist in mammalian cells. These include equilibrative nucleoside transporters that transport nucleosides in a gradient-dependent fashion and concentrative nucleoside transporters that import nucleosides against a gradient by coupling movement with sodium transport. Particular emphasis is placed on describing the roles of nucleoside transport in normal physiological processes, including inflammation, cardiovascular function and nutrient transport across the blood–brain barrier. In addition, the role of nucleoside transport in pathological conditions such as cardiovascular disease and cancer are discussed. The potential therapeutic applications of manipulating nucleoside transport activities are discussed, focusing on nucleoside analogs as anti-neoplastic agents. Finally, we discuss future directions for the development of novel chemical entities to measure nucleoside transport activity at the cellular and organismal level.
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Niu HY, Xia C, Qu GR, Wu S, Jiang Y, Jin X, Guo HM. Microwave-Promoted “One-Pot” Synthesis of 4-Nitrobenzylthioinosine Analogues Using Thiourea as a Sulfur Precursor. Chem Asian J 2011; 7:45-9. [DOI: 10.1002/asia.201100699] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Indexed: 11/06/2022]
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Lin W, Buolamwini JK. Design, synthesis, and evaluation of 2-diethanolamino-4,8-diheptamethyleneimino-2-(N-aminoethyl-N-ethanolamino)-6-(N,N-diethanolamino)pyrimido[5,4-d]pyrimidine-fluorescein conjugate (8MDP-fluor), as a novel equilibrative nucleoside transporter probe. Bioconjug Chem 2011; 22:1221-7. [PMID: 21539390 DOI: 10.1021/bc2000758] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Nucleoside transporters are integral membrane glycoproteins that play critical roles in physiological nucleoside and nucleobase fluxes, and influence the efficacy of many nucleoside chemotherapy drugs. Fluorescent reporter ligands/substrates have been shown to be useful in the analysis of nucleoside transporter (NT) protein expression and discovery of new NT inhibitors. In this study, we have developed a novel dipyridamole (DP)-based equilibrative nucleoside transporter 1 (ENT1) fluorescent probe. The potent ENT1 and ENT2 inhibitor analogue of dipyridamole, 2,6-bis(diethanolamino)-4,8-diheptamethyleneiminopyrimido[5,4-d]pyrimidine (4, 8MDP), was modified to replace one β-hydroxyethyl group of the amino substituent at the 2-position with a β-aminoethyl group and then conjugated through the amino group to 6-(fluorescein-5-carboxamido)hexanoyl moiety to obtain a new fluorescent molecule, 2-diethanolamino-4,8-diheptamethyleneimino-2-(N-aminoethyl-N-ethanolamino)-6-(N,N-diethanolamino)pyrimido[5,4-d]pyrimidine-fluorescein conjugate, designated 8MDP-fluorescein (8MDP-fluor, 6). The binding affinities of 8MDP-fluor at ENT1 and ENT2 are reflected by the uridine uptake inhibitory K(i) values of 52.1 nM and 285 nM, respectively. 8MDP-fluor was successfully demonstrated to be a flow cytometric probe for ENT1 comparable to the nitrobenzylmercaptopurine riboside (NBMPR) analogue ENT1 fluorescent probe SAENTA-X8-fluorescein (SAENTA-fluor, 1). This is the first reported dipyridamole-based ENT1 fluorescent probe, which adds a novel tool for probing ENT1, and possibly ENT2.
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Affiliation(s)
- Wenwei Lin
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Sciences Center, Memphis, Tennessee 38163, United States
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Devine SM, Scammells PJ. Synthesis and Utility of 2-Halo-O6-(benzotriazol-1-yl)-Functionalized Purine Nucleosides. European J Org Chem 2010. [DOI: 10.1002/ejoc.201001395] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Gupte A, Buolamwini JK. CoMFA and CoMSIA 3D-QSAR studies on S6-(4-nitrobenzyl)mercaptopurine riboside (NBMPR) analogs as inhibitors of human equilibrative nucleoside transporter 1 (hENT1). Bioorg Med Chem Lett 2009; 19:314-8. [DOI: 10.1016/j.bmcl.2008.11.092] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2008] [Revised: 11/20/2008] [Accepted: 11/24/2008] [Indexed: 11/15/2022]
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