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Puris E, Gynther M, Auriola S, Huttunen KM. L-Type amino acid transporter 1 as a target for drug delivery. Pharm Res 2020; 37:88. [PMID: 32377929 PMCID: PMC7203094 DOI: 10.1007/s11095-020-02826-8] [Citation(s) in RCA: 84] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 04/15/2020] [Indexed: 12/13/2022]
Abstract
Our growing understanding of membrane transporters and their substrate specificity has opened a new avenue in the field of targeted drug delivery. The L-type amino acid transporter 1 (LAT1) has been one of the most extensively investigated transporters for delivering drugs across biological barriers. The transporter is predominantly expressed in cerebral cortex, blood-brain barrier, blood-retina barrier, testis, placenta, bone marrow and several types of cancer. Its physiological function is to mediate Na+ and pH independent exchange of essential amino acids: leucine, phenylalanine, etc. Several drugs and prodrugs designed as LAT1 substrates have been developed to improve targeted delivery into the brain and cancer cells. Thus, the anti-parkinsonian drug, L-Dopa, the anti-cancer drug, melphalan and the anti-epileptic drug gabapentin, all used in clinical practice, utilize LAT1 to reach their target site. These examples provide supporting evidence for the utility of the LAT1-mediated targeted delivery of the (pro)drug. This review comprehensively summarizes recent advances in LAT1-mediated targeted drug delivery. In addition, the use of LAT1 is critically evaluated and limitations of the approach are discussed.
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Affiliation(s)
- Elena Puris
- School of Pharmacy, University of Eastern Finland, P.O. Box 1627, FI-70211, Kuopio, Finland.
- Institute of Pharmacy and Molecular Biotechnology, Ruprecht-Karls-University, 69120, Heidelberg, Germany.
| | - Mikko Gynther
- School of Pharmacy, University of Eastern Finland, P.O. Box 1627, FI-70211, Kuopio, Finland
| | - Seppo Auriola
- School of Pharmacy, University of Eastern Finland, P.O. Box 1627, FI-70211, Kuopio, Finland
| | - Kristiina M Huttunen
- School of Pharmacy, University of Eastern Finland, P.O. Box 1627, FI-70211, Kuopio, Finland
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52
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Groeneweg S, van Geest FS, Peeters RP, Heuer H, Visser WE. Thyroid Hormone Transporters. Endocr Rev 2020; 41:5637505. [PMID: 31754699 DOI: 10.1210/endrev/bnz008] [Citation(s) in RCA: 102] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 11/07/2019] [Indexed: 02/08/2023]
Abstract
Thyroid hormone transporters at the plasma membrane govern intracellular bioavailability of thyroid hormone. Monocarboxylate transporter (MCT) 8 and MCT10, organic anion transporting polypeptide (OATP) 1C1, and SLC17A4 are currently known as transporters displaying the highest specificity toward thyroid hormones. Structure-function studies using homology modeling and mutational screens have led to better understanding of the molecular basis of thyroid hormone transport. Mutations in MCT8 and in OATP1C1 have been associated with clinical disorders. Different animal models have provided insight into the functional role of thyroid hormone transporters, in particular MCT8. Different treatment strategies for MCT8 deficiency have been explored, of which thyroid hormone analogue therapy is currently applied in patients. Future studies may reveal the identity of as-yet-undiscovered thyroid hormone transporters. Complementary studies employing animal and human models will provide further insight into the role of transporters in health and disease. (Endocrine Reviews 41: 1 - 55, 2020).
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Affiliation(s)
- Stefan Groeneweg
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, the Netherlands Academic Center for Thyroid Diseases, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Ferdy S van Geest
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, the Netherlands Academic Center for Thyroid Diseases, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Robin P Peeters
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, the Netherlands Academic Center for Thyroid Diseases, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Heike Heuer
- Department of Endocrinology, Diabetes and Metabolism, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - W Edward Visser
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, the Netherlands Academic Center for Thyroid Diseases, Erasmus Medical Center, Rotterdam, the Netherlands
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53
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Li S, Su W, Wu H, Yuan T, Yuan C, Liu J, Deng G, Gao X, Chen Z, Bao Y, Yuan F, Zhou S, Tan H, Li Y, Li X, Fan L, Zhu J, Chen AT, Liu F, Zhou Y, Li M, Zhai X, Zhou J. Targeted tumour theranostics in mice via carbon quantum dots structurally mimicking large amino acids. Nat Biomed Eng 2020; 4:704-716. [PMID: 32231314 PMCID: PMC7197249 DOI: 10.1038/s41551-020-0540-y] [Citation(s) in RCA: 168] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 02/20/2020] [Indexed: 12/28/2022]
Abstract
Strategies for selectively imaging and delivering drugs to tumours typically leverage differentially upregulated surface molecules on cancer cells. Here, we show that intravenously injected carbon quantum dots, functionalized with multiple paired α-carboxyl and amino groups that bind to the large neutral amino acid transporter 1 (which is expressed in most tumours), selectively accumulate in human tumour xenografts in mice and in an orthotopic mouse model of human glioma. The functionalized quantum dots, which structurally mimic large amino acids and can be loaded with aromatic drugs through π–π stacking interactions, enabled—in the absence of detectable toxicity—near-infrared fluorescence and photoacoustic imaging of the tumours and a reduction in tumour burden after the targeted delivery of chemotherapeutics to the tumours. The versatility of functionalization and high tumour selectivity of the quantum dots make them broadly suitable for tumour-specific imaging and drug delivery. Intravenously injected functionalized carbon quantum dots that bind to the large neutral amino acid transporter 1 and that structurally mimic large amino acids selectively accumulate in human tumours in mice, facilitating targeted theranostics.
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Affiliation(s)
- Shuhua Li
- College of Chemistry, Key Laboratories of Theoretical and Computational Photochemistry, and Radiopharmaceuticals, Ministry of Education, Beijing Normal University, Beijing, China
| | - Wen Su
- College of Chemistry, Key Laboratories of Theoretical and Computational Photochemistry, and Radiopharmaceuticals, Ministry of Education, Beijing Normal University, Beijing, China
| | - Hao Wu
- College of Chemistry, Key Laboratories of Theoretical and Computational Photochemistry, and Radiopharmaceuticals, Ministry of Education, Beijing Normal University, Beijing, China
| | - Ting Yuan
- College of Chemistry, Key Laboratories of Theoretical and Computational Photochemistry, and Radiopharmaceuticals, Ministry of Education, Beijing Normal University, Beijing, China
| | - Chang Yuan
- College of Chemistry, Key Laboratories of Theoretical and Computational Photochemistry, and Radiopharmaceuticals, Ministry of Education, Beijing Normal University, Beijing, China
| | - Jun Liu
- Department of Neurosurgery, Yale University, New Haven, CT, USA
| | - Gang Deng
- Department of Neurosurgery, Yale University, New Haven, CT, USA
| | - Xingchun Gao
- Department of Neurosurgery, Yale University, New Haven, CT, USA
| | - Zeming Chen
- Department of Neurosurgery, Yale University, New Haven, CT, USA
| | - Youmei Bao
- Department of Neurosurgery, Yale University, New Haven, CT, USA
| | - Fanglong Yuan
- College of Chemistry, Key Laboratories of Theoretical and Computational Photochemistry, and Radiopharmaceuticals, Ministry of Education, Beijing Normal University, Beijing, China
| | - Shixin Zhou
- Department of Cell Biology and Stem Cell Research Center, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Hongwei Tan
- College of Chemistry, Key Laboratories of Theoretical and Computational Photochemistry, and Radiopharmaceuticals, Ministry of Education, Beijing Normal University, Beijing, China
| | - Yunchao Li
- College of Chemistry, Key Laboratories of Theoretical and Computational Photochemistry, and Radiopharmaceuticals, Ministry of Education, Beijing Normal University, Beijing, China
| | - Xiaohong Li
- College of Chemistry, Key Laboratories of Theoretical and Computational Photochemistry, and Radiopharmaceuticals, Ministry of Education, Beijing Normal University, Beijing, China
| | - Louzhen Fan
- College of Chemistry, Key Laboratories of Theoretical and Computational Photochemistry, and Radiopharmaceuticals, Ministry of Education, Beijing Normal University, Beijing, China.
| | - Jia Zhu
- College of Chemistry, Key Laboratories of Theoretical and Computational Photochemistry, and Radiopharmaceuticals, Ministry of Education, Beijing Normal University, Beijing, China.
| | - Ann T Chen
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Fuyao Liu
- Department of Neurosurgery, Yale University, New Haven, CT, USA
| | - Yu Zhou
- Department of Neurosurgery, Yale University, New Haven, CT, USA
| | - Miao Li
- Department of Neurosurgery, Yale University, New Haven, CT, USA
| | - Xingchen Zhai
- Department of Neurosurgery, Yale University, New Haven, CT, USA
| | - Jiangbing Zhou
- Department of Neurosurgery, Yale University, New Haven, CT, USA. .,Department of Biomedical Engineering, Yale University, New Haven, CT, USA.
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54
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Scalise M, Pochini L, Galluccio M, Console L, Indiveri C. Glutamine transporters as pharmacological targets: From function to drug design. Asian J Pharm Sci 2020; 15:207-219. [PMID: 32373200 PMCID: PMC7193454 DOI: 10.1016/j.ajps.2020.02.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 02/18/2020] [Accepted: 02/29/2020] [Indexed: 12/17/2022] Open
Abstract
Among the different targets of administered drugs, there are membrane transporters that play also a role in drug delivery and disposition. Moreover, drug-transporter interactions are responsible for off-target effects of drugs underlying their toxicity. The improvement of the drug design process is subjected to the identification of those membrane transporters mostly relevant for drug absorption, delivery and side effect production. A peculiar group of proteins with great relevance to pharmacology is constituted by the membrane transporters responsible for managing glutamine traffic in different body districts. The interest around glutamine metabolism lies in its physio-pathological role; glutamine is considered a conditionally essential amino acid because highly proliferative cells have an increased request of glutamine that cannot be satisfied only by endogenous synthesis. Then, glutamine transporters provide cells with this special nutrient. Among the glutamine transporters, SLC1A5, SLC6A14, SLC6A19, SLC7A5, SLC7A8 and some members of SLC38 family are the best characterized, so far, in both physiological and pathological conditions. Few 3D structures have been solved by CryoEM; other structural data on these transporters have been obtained by computational analysis. Interactions with drugs have been described for several transporters of this group. For some of them, the studies are at an advanced stage, for others, the studies are still in nuce and novel biochemical findings open intriguing perspectives.
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Affiliation(s)
- Mariafrancesca Scalise
- Department of DiBEST (Biologia, Ecologia e Scienze della Terra), University of Calabria, Arcavacata di Rende (CS) 87036, Italy
| | - Lorena Pochini
- Department of DiBEST (Biologia, Ecologia e Scienze della Terra), University of Calabria, Arcavacata di Rende (CS) 87036, Italy
| | - Michele Galluccio
- Department of DiBEST (Biologia, Ecologia e Scienze della Terra), University of Calabria, Arcavacata di Rende (CS) 87036, Italy
| | - Lara Console
- Department of DiBEST (Biologia, Ecologia e Scienze della Terra), University of Calabria, Arcavacata di Rende (CS) 87036, Italy
| | - Cesare Indiveri
- Department of DiBEST (Biologia, Ecologia e Scienze della Terra), University of Calabria, Arcavacata di Rende (CS) 87036, Italy
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55
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Asc-1 Transporter (SLC7A10): Homology Models And Molecular Dynamics Insights Into The First Steps Of The Transport Mechanism. Sci Rep 2020; 10:3731. [PMID: 32111919 PMCID: PMC7048771 DOI: 10.1038/s41598-020-60617-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Accepted: 02/14/2020] [Indexed: 12/02/2022] Open
Abstract
The alanine-serine-cysteine transporter Asc-1 regulates the synaptic availability of d-serine and glycine (the two co-agonists of the NMDA receptor) and is regarded as an important drug target. To shuttle the substrate from the extracellular space to the cytoplasm, this transporter undergoes multiple distinct conformational states. In this work, homology modeling, substrate docking and molecular dynamics simulations were carried out to learn more about the transition between the “outward-open” and “outward-open occluded” states. We identified a transition state involving the highly-conserved unwound TM6 region in which the Phe243 flips close to the d-serine substrate without major movements of TM6. This feature and those of other key residues are proposed to control the binding site and substrate translocation. Competitive inhibitors ACPP, LuAE00527 and SMLC were docked and their binding modes at the substrate binding site corroborated the key role played by Phe243 of TM6. For ACPP and LuAE00527, strong hydrophobic interactions with this residue hinder its mobility and prevent the uptake and the efflux of substrates. As for SMLC, the weaker interactions maintain the flexibility of Phe243 and the efflux process. Overall, we propose a molecular basis for the inhibition of substrate translocation of the Asc-1 transporter that should be valuable for rational drug design.
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56
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Fagundes NS, Milfort MC, Williams SM, Da Costa MJ, Fuller AL, Menten JF, Rekaya R, Aggrey SE. Dietary methionine level alters growth, digestibility, and gene expression of amino acid transporters in meat-type chickens. Poult Sci 2020; 99:67-75. [PMID: 32416854 PMCID: PMC7587823 DOI: 10.3382/ps/pez588] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Accepted: 10/01/2019] [Indexed: 01/16/2023] Open
Abstract
Imbalance in nutrients can affect digestibility of amino acids by altering gene expression of amino acid transporters. We investigated digestibility and molecular transporters of essential amino acids in chickens fed a methionine-deficient diet. A total of 40 chicks (23 D old) were randomly assigned to either a control (0.49% methionine) or a deficient (0.28%) diet until 41 D when they were sampled for Pectoralis (P.) major, kidney, ileum, and hypothalamus for mRNA expression analysis. The ileal content was collected for apparent ileal digestibility (AID) analysis. Birds fed the deficient diet had reduced growth and worse feed efficiency compared to control. The AID of methionine was similar between both groups. The AID of other essential amino acids was higher in the deficient group than control. mRNA expression of b0,+ AT and LAT4 were upregulated in the ileum and kidney but LAT1 was downregulated only in kidney of the deficient group compared to control. In the P. major, SNAT1, SNAT2, and CAT1 were upregulated in the deficient group compared to control. A diet deficiency in methionine affects digestibility of essential amino acids and cysteine, but not the digestibility of methionine. The change in digestibility is reflected in the mRNA expression of amino acid transporters across different tissues.
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Affiliation(s)
- Naiara S Fagundes
- NutriGenomics Laboratory, Department of Poultry Science, University of Georgia, Athens, GA 30602; Department of Animal Science, University of Sao Paulo, Piracicaba, Sao Paulo, Brazil
| | - Marie C Milfort
- NutriGenomics Laboratory, Department of Poultry Science, University of Georgia, Athens, GA 30602
| | - Susan M Williams
- Department of Population Health, University of Georgia, Athens, GA 30602
| | - Manuel J Da Costa
- NutriGenomics Laboratory, Department of Poultry Science, University of Georgia, Athens, GA 30602
| | - Alberta L Fuller
- NutriGenomics Laboratory, Department of Poultry Science, University of Georgia, Athens, GA 30602
| | - José F Menten
- Department of Animal Science, University of Sao Paulo, Piracicaba, Sao Paulo, Brazil
| | - Romdhane Rekaya
- Department of Animal and Dairy Science, University of Georgia, Athens, GA 30602
| | - Samuel E Aggrey
- NutriGenomics Laboratory, Department of Poultry Science, University of Georgia, Athens, GA 30602.
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57
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The solute carrier transporters and the brain: Physiological and pharmacological implications. Asian J Pharm Sci 2019; 15:131-144. [PMID: 32373195 PMCID: PMC7193445 DOI: 10.1016/j.ajps.2019.09.002] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Revised: 08/17/2019] [Accepted: 09/27/2019] [Indexed: 02/05/2023] Open
Abstract
Solute carriers (SLCs) are the largest family of transmembrane transporters that determine the exchange of various substances, including nutrients, ions, metabolites, and drugs across biological membranes. To date, the presence of about 287 SLC genes have been identified in the brain, among which mutations or the resultant dysfunctions of 71 SLC genes have been reported to be correlated with human brain disorders. Although increasing interest in SLCs have focused on drug development, SLCs are currently still under-explored as drug targets, especially in the brain. We summarize the main substrates and functions of SLCs that are expressed in the brain, with an emphasis on selected SLCs that are important physiologically, pathologically, and pharmacologically in the blood-brain barrier, astrocytes, and neurons. Evidence suggests that a fraction of SLCs are regulated along with the occurrences of brain disorders, among which epilepsy, neurodegenerative diseases, and autism are representative. Given the review of SLCs involved in the onset and procession of brain disorders, we hope these SLCs will be screened as promising drug targets to improve drug delivery to the brain.
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58
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de Sousa IH, Campos VNS, Vale AAM, Maciel-Silva VL, Leite CM, Lopes AJO, Mourão PS, das Chagas Alves Lima F, Batista AA, de Azevedo Dos Santos APS, Almeida MAP, Pereira SRF. Ruthenium (II) complexes with N, O-chelating proline and threonine ligands cause selective cytotoxicity by the induction of genomic instability, cell cycle arrest and apoptosis in breast and prostate tumor cells. Toxicol In Vitro 2019; 62:104679. [PMID: 31676337 DOI: 10.1016/j.tiv.2019.104679] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 09/20/2019] [Accepted: 10/05/2019] [Indexed: 12/27/2022]
Abstract
Ruthenium complexes are being considered as novel chemotherapeutic alternatives for cancer treatment. In our study, we assessed the antitumoral activities of novel ruthenium complexes coupled to the amino acids proline (RuPro) and threonine (RuThr) in prostate tumor cell lines (DU145) and breast (MCF7), and normal cell lines of the lung fibroblast (GM07492A). Our results revealed that the EC50 of the complexes for DU145 and MCF7 was two times lower than that GM07492A. Moreover, RuPro and RuThr were not able to induce significant genomic instability, cell cycle arrest or cell death in GM07492A, but could induce DNA damage, arrest in G2/M and apoptosis in DU145 and MCF7. Furthermore, BAX, TP53 and ATM were found to be upregulated in DU145 and MCF7 treated with RuPro and RuThr, in which, a higher ASCT2 gene expression was also observed. Using molecular docking, RuPro and RuThr interact with ASCT2, suggesting that this transporter might have a pivotal role in the execution of their activities. Hence, our results with RuPro and RuThr are capable of selectively inducing genetic damage, cell cycle arrest and apoptosis in DU145 and MCF7. We suggest that the selective action of the RuPro and RuThr complexes is related to the higher expression of ASCT2 in the tumor cells.
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Affiliation(s)
- Israel Higino de Sousa
- Postgraduate Program in Biodiversity and Biotechnology-BIONORTE, Federal University of Maranhão, Dom Delgado University City, 1966, CEP. 65085-580, São Luís, MA, Brazil; Laboratory of Genetics and Molecular Biology, Department of Biology, Federal University of Maranhão, Brazil.
| | | | - André Alvares Marques Vale
- Postgraduate Program in Health Sciences, Federal University of Maranhão, Brazil; Laboratory of Immunology applied to Cancer, Department of Physiological Sciences, Federal University of Maranhão, Brazil
| | - Vera Lucia Maciel-Silva
- Postgraduate Program in Biodiversity and Biotechnology-BIONORTE, Federal University of Maranhão, Dom Delgado University City, 1966, CEP. 65085-580, São Luís, MA, Brazil; Laboratory of Genetics and Molecular Biology, Department of Biology, Federal University of Maranhão, Brazil; Department of Chemistry and Biology, State University of Maranhão, Paul VI campus, CEP 65055970, São Luis, MA, Brazil
| | - Celisnolia Moraes Leite
- Department of Chemistry, Federal University of São Carlos, CP 676, CEP 13565-905, São Carlos, SP, Brazil
| | - Alberto Jorge Oliveira Lopes
- Postgraduate Program in Health Sciences, Federal University of Maranhão, Brazil; Research Group in Computational Quantum Chemistry & Pharmaceutical Planning, State University of Piauí, GPQQ&PF/UESPI, Teresina, PI, Brazil
| | - Penina Sousa Mourão
- Research Group in Computational Quantum Chemistry & Pharmaceutical Planning, State University of Piauí, GPQQ&PF/UESPI, Teresina, PI, Brazil
| | - Francisco das Chagas Alves Lima
- Research Group in Computational Quantum Chemistry & Pharmaceutical Planning, State University of Piauí, GPQQ&PF/UESPI, Teresina, PI, Brazil
| | - Alzir Azevedo Batista
- Department of Chemistry, Federal University of São Carlos, CP 676, CEP 13565-905, São Carlos, SP, Brazil
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Role of L-Type Amino Acid Transporter 1 (LAT1) for the Selective Cytotoxicity of Sesamol in Human Melanoma Cells. Molecules 2019; 24:molecules24213869. [PMID: 31717859 PMCID: PMC6865181 DOI: 10.3390/molecules24213869] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Revised: 10/21/2019] [Accepted: 10/25/2019] [Indexed: 11/18/2022] Open
Abstract
Sesamol is effective against melanoma cells with less damage to normal cells. The underlying selective cytotoxicity of sesamol in melanoma vs. non-cancerous cells is undefined. Melanoma cells differ from normal cells by over-expression of the L-type amino acid transporter 1 (LAT1). We sought to clarify the transport mechanism on selective cytotoxicity of sesamol in melanoma cells. A human melanoma cell line (SK-MEL-2) and African monkey epithelial cell line (Vero) were used to study the cellular uptake and cytotoxicity of sesamol. The intracellular concentration of sesamol was quantified by UV-HPLC. The cytotoxicity was determined by neutral red uptake assay. Sesamol showed a higher distribution volume and uptake clearance in SK-MEL-2 than Vero cells. Sesamol was distributed by both carrier-mediated and passive transport by having greater carrier-mediated transport into SK-MEL-2 cells than Vero cells. Higher mRNA expression and function of LAT1 over LAT2 were evident in SK-MEL-2 cells compared to Vero cells. Sesamol uptake and sesamol cytotoxicity were inhibited by the LAT1 inhibitor, suggesting LAT1 had a role in sesamol transport and its bioactivity in melanoma. The LAT1-mediated transport of sesamol is indicative of how it engages cytotoxicity in melanoma cells with promising therapeutic benefits.
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60
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Rigorous sampling of docking poses unveils binding hypothesis for the halogenated ligands of L-type Amino acid Transporter 1 (LAT1). Sci Rep 2019; 9:15061. [PMID: 31636293 PMCID: PMC6803698 DOI: 10.1038/s41598-019-51455-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 09/24/2019] [Indexed: 12/15/2022] Open
Abstract
L-type Amino acid Transporter 1 (LAT1) plays a significant role in the growth and propagation of cancer cells by facilitating the cross-membrane transport of essential nutrients, and is an attractive drug target. Several halogen-containing L-phenylalanine-based ligands display high affinity and high selectivity for LAT1; nonetheless, their molecular mechanism of binding remains unclear. In this study, a combined in silico strategy consisting of homology modeling, molecular docking, and Quantum Mechanics-Molecular Mechanics (QM-MM) simulation was applied to elucidate the molecular basis of ligand binding in LAT1. First, a homology model of LAT1 based on the atomic structure of a prokaryotic homolog was constructed. Docking studies using a set of halogenated ligands allowed for deriving a binding hypothesis. Selected docking poses were subjected to QM-MM calculations to investigate the halogen interactions. Collectively, the results highlight the dual nature of the ligand-protein binding mode characterized by backbone hydrogen bond interactions of the amino acid moiety of the ligands and residues I63, S66, G67, F252, G255, as well as hydrophobic interactions of the ligand’s side chains with residues I139, I140, F252, G255, F402, W405. QM-MM optimizations indicated that the electrostatic interactions involving halogens contribute to the binding free energy. Importantly, our results are in good agreement with the recently unraveled cryo-Electron Microscopy structures of LAT1.
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61
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Abstract
Amino acids perform a variety of functions in cells and organisms, particularly in the synthesis of proteins, as energy metabolites, neurotransmitters, and precursors for many other molecules. Amino acid transport plays a key role in all these functions. Inhibition of amino acid transport is pursued as a therapeutic strategy in several areas, such as diabetes and related metabolic disorders, neurological disorders, cancer, and stem cell biology. The role of amino acid transporters in these disorders and processes is well established, but the implementation of amino acid transporters as drug targets is still in its infancy. This is at least in part due to the underdeveloped pharmacology of this group of membrane proteins. Recent advances in structural biology, membrane protein expression, and inhibitor screening methodology will see an increased number of improved and selective inhibitors of amino acid transporters that can serve as tool compounds for further studies.
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Affiliation(s)
- Stefan Bröer
- 1 Research School of Biology, College of Science, The Australian National University, Canberra, ACT, Australia
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62
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Sinigaglia M, Assi T, Besson FL, Ammari S, Edjlali M, Feltus W, Rozenblum-Beddok L, Zhao B, Schwartz LH, Mokrane FZ, Dercle L. Imaging-guided precision medicine in glioblastoma patients treated with immune checkpoint modulators: research trend and future directions in the field of imaging biomarkers and artificial intelligence. EJNMMI Res 2019; 9:78. [PMID: 31432278 PMCID: PMC6702257 DOI: 10.1186/s13550-019-0542-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 07/19/2019] [Indexed: 12/14/2022] Open
Abstract
Immunotherapies that employ immune checkpoint modulators (ICMs) have emerged as an effective treatment for a variety of solid cancers, as well as a paradigm shift in the treatment of cancers. Despite this breakthrough, the median survival time of glioblastoma patients has remained at about 2 years. Therefore, the safety and anti-cancer efficacy of combination therapies that include ICMs are being actively investigated. Because of the distinct mechanisms of ICMs, which restore the immune system’s anti-tumor capacity, unconventional immune-related phenomena are increasingly being reported in terms of tumor response and progression, as well as adverse events. Indeed, immunotherapy response assessments for neuro-oncology (iRANO) play a central role in guiding cancer patient management and define a “wait and see strategy” for patients treated with ICMs in monotherapy with progressive disease on MRI. This article deciphers emerging research trends to ameliorate four challenges unaddressed by the iRANO criteria: (1) patient selection, (2) identification of immune-related phenomena other than pseudoprogression (i.e., hyperprogression, the abscopal effect, immune-related adverse events), (3) response assessment in combination therapies including ICM, and (4) alternatives to MRI. To this end, our article provides a structured approach for standardized selection and reporting of imaging modalities to enable the use of precision medicine by deciphering the characteristics of the tumor and its immune environment. Emerging preclinical or clinical innovations are also discussed as future directions such as immune-specific targeting and implementation of artificial intelligence algorithms.
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Affiliation(s)
- Mathieu Sinigaglia
- Department of Imaging Nuclear Medicine, Institut Claudius Regaud-Institut Universitaire du Cancer de Toulouse-Oncopole, Toulouse, France
| | - Tarek Assi
- Département de médecine oncologique, Gustave Roussy, Université Paris-Saclay, 94805, Villejuif, France
| | - Florent L Besson
- Department of Biophysics and Nuclear Medicine, Bicêtre University Hospital, Assistance Publique-Hôpitaux de Paris, 78 rue du Général Leclerc, 94275, Le Kremlin-Bicêtre, France.,IR4M-UMR 8081, CNRS, Université Paris Sud, Université Paris Saclay, Orsay, France
| | - Samy Ammari
- Département d'imagerie médicale, Gustave Roussy, Université Paris-Saclay, 94805, Villejuif, France
| | - Myriam Edjlali
- INSERM U894, Service d'imagerie morphologique et fonctionnelle, Hôpital Sainte-Anne, Université Paris Descartes, 1, rue Cabanis, 75014, Paris, France
| | - Whitney Feltus
- Department of Radiology, New York Presbyterian Hospital-Columbia University Medical Center, New York, NY, 10039, USA
| | - Laura Rozenblum-Beddok
- Service de Médecine Nucléaire, AP-HP, Hôpital La Pitié-Salpêtrière, Sorbonne Université, 75013, Paris, France
| | - Binsheng Zhao
- Department of Radiology, New York Presbyterian Hospital-Columbia University Medical Center, New York, NY, 10039, USA
| | - Lawrence H Schwartz
- Department of Radiology, New York Presbyterian Hospital-Columbia University Medical Center, New York, NY, 10039, USA
| | - Fatima-Zohra Mokrane
- Department of Radiology, New York Presbyterian Hospital-Columbia University Medical Center, New York, NY, 10039, USA.,Département d'imagerie médicale, CHU Rangueil, Université Toulouse Paul Sabatier, Toulouse, France
| | - Laurent Dercle
- Department of Radiology, New York Presbyterian Hospital-Columbia University Medical Center, New York, NY, 10039, USA. .,UMR1015, Institut Gustave Roussy, Université Paris Saclay, 94800, Villejuif, France.
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63
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Ozaki K, Yamada T, Horie T, Ishizaki A, Hiraiwa M, Iezaki T, Park G, Fukasawa K, Kamada H, Tokumura K, Motono M, Kaneda K, Ogawa K, Ochi H, Sato S, Kobayashi Y, Shi YB, Taylor PM, Hinoi E. The L-type amino acid transporter LAT1 inhibits osteoclastogenesis and maintains bone homeostasis through the mTORC1 pathway. Sci Signal 2019; 12:12/589/eaaw3921. [PMID: 31289211 DOI: 10.1126/scisignal.aaw3921] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
L-type amino acid transporter 1 (LAT1), which is encoded by solute carrier transporter 7a5 (Slc7a5), plays a crucial role in amino acid sensing and signaling in specific cell types, contributing to the pathogenesis of cancer and neurological disorders. Amino acid substrates of LAT1 have a beneficial effect on bone health directly and indirectly, suggesting a potential role for LAT1 in bone homeostasis. Here, we identified LAT1 in osteoclasts as important for bone homeostasis. Slc7a5 expression was substantially reduced in osteoclasts in a mouse model of ovariectomy-induced osteoporosis. The osteoclast-specific deletion of Slc7a5 in mice led to osteoclast activation and bone loss in vivo, and Slc7a5 deficiency increased osteoclastogenesis in vitro. Loss of Slc7a5 impaired activation of the mechanistic target of rapamycin complex 1 (mTORC1) pathway in osteoclasts, whereas genetic activation of mTORC1 corrected the enhanced osteoclastogenesis and bone loss in Slc7a5-deficient mice. Last, Slc7a5 deficiency increased the expression of nuclear factor of activated T cells, cytoplasmic 1 (Nfatc1) and the nuclear accumulation of NFATc1, a master regulator of osteoclast function, possibly through the canonical nuclear factor κB pathway and the Akt-glycogen synthase kinase 3β signaling axis, respectively. These findings suggest that the LAT1-mTORC1 axis plays a pivotal role in bone resorption and bone homeostasis by modulating NFATc1 in osteoclasts, thereby providing a molecular connection between amino acid intake and skeletal integrity.
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Affiliation(s)
- Kakeru Ozaki
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan
| | - Takanori Yamada
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan
| | - Tetsuhiro Horie
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan
| | - Atsushi Ishizaki
- Laboratory of Clinical Analytical Sciences, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan
| | - Manami Hiraiwa
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan
| | - Takashi Iezaki
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan.,Venture Business Laboratory, Organization of Frontier Science and Innovation, Kanazawa University, Kanazawa, Ishikawa 920-1192, Japan
| | - Gyujin Park
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan
| | - Kazuya Fukasawa
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan
| | - Hikari Kamada
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan
| | - Kazuya Tokumura
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan
| | - Mei Motono
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan
| | - Katsuyuki Kaneda
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan
| | - Kazuma Ogawa
- Laboratory of Clinical Analytical Sciences, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan.,Institute for Frontier Science Initiative, Kanazawa University, Kanazawa, Ishikawa 920-1192, Japan
| | - Hiroki Ochi
- Department of Physiology and Cell Biology, Tokyo Medical and Dental University, Graduate School, Tokyo 113-8510, Japan
| | - Shingo Sato
- Department of Physiology and Cell Biology, Tokyo Medical and Dental University, Graduate School, Tokyo 113-8510, Japan
| | - Yasuhiro Kobayashi
- Institute for Oral Science, Matsumoto Dental University, Shiojiri, Nagano 399-0781, Japan
| | - Yun-Bo Shi
- Section on Molecular Morphogenesis, Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Peter M Taylor
- Division of Cell Signalling and Immunology, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Eiichi Hinoi
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School, Kanazawa, Ishikawa 920-1192, Japan.
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64
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Kyriakou S, Mitsiogianni M, Mantso T, Cheung W, Todryk S, Veuger S, Pappa A, Tetard D, Panayiotidis MI. Anticancer activity of a novel methylated analogue of L-mimosine against an in vitro model of human malignant melanoma. Invest New Drugs 2019; 38:621-633. [PMID: 31240512 PMCID: PMC7211211 DOI: 10.1007/s10637-019-00809-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 06/05/2019] [Indexed: 12/18/2022]
Abstract
The anticancer activity of a series of novel synthesized, hydroxypyridone-based metal chelators (analogues of L-mimosine) was evaluated in an in vitro model of melanoma consisting of malignant melanoma (A375), non-melanoma epidermoid carcinoma (A431) and immortalized non-malignant keratinocyte (HaCaT) cells. More specifically, we have demonstrated that the L-enantiomer of a methylated analogue of L-mimosine (compound 22) can exert a potent anticancer effect in A375 cells when compared to either A431 or HaCaT cells. Moreover, we have demonstrated that this analogue has the ability to i) promote increased generation of reactive oxygen species (ROS), ii) activate both intrinsic and extrinsic apoptosis and iii) induce perturbations in cell cycle growth arrest. Our data highlights the potential of compound 22 to act as a promising therapeutic agent against an in vitro model of human malignant melanoma.
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Affiliation(s)
- Sotiris Kyriakou
- Department of Applied Sciences, Northumbria University, Newcastle Upon Tyne, UK
| | - Melina Mitsiogianni
- Department of Applied Sciences, Northumbria University, Newcastle Upon Tyne, UK
| | - Theodora Mantso
- Department of Applied Sciences, Northumbria University, Newcastle Upon Tyne, UK
| | - William Cheung
- Department of Applied Sciences, Northumbria University, Newcastle Upon Tyne, UK
| | - Stephen Todryk
- Department of Applied Sciences, Northumbria University, Newcastle Upon Tyne, UK
| | - Stephany Veuger
- Department of Applied Sciences, Northumbria University, Newcastle Upon Tyne, UK
| | - Aglaia Pappa
- Department of Molecular Biology & Genetics, Democritus University of Thrace, Alexandroupolis, Greece
| | - David Tetard
- Department of Applied Sciences, Northumbria University, Newcastle Upon Tyne, UK
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65
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Abdul Razzak R, Florence GJ, Gunn-Moore FJ. Approaches to CNS Drug Delivery with a Focus on Transporter-Mediated Transcytosis. Int J Mol Sci 2019; 20:E3108. [PMID: 31242683 PMCID: PMC6627589 DOI: 10.3390/ijms20123108] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 06/15/2019] [Accepted: 06/16/2019] [Indexed: 12/13/2022] Open
Abstract
Drug delivery to the central nervous system (CNS) conferred by brain barriers is a major obstacle in the development of effective neurotherapeutics. In this review, a classification of current approaches of clinical or investigational importance for the delivery of therapeutics to the CNS is presented. This classification includes the use of formulations administered systemically that can elicit transcytosis-mediated transport by interacting with transporters expressed by transvascular endothelial cells. Neurotherapeutics can also be delivered to the CNS by means of surgical intervention using specialized catheters or implantable reservoirs. Strategies for delivering drugs to the CNS have evolved tremendously during the last two decades, yet, some factors can affect the quality of data generated in preclinical investigation, which can hamper the extension of the applications of these strategies into clinically useful tools. Here, we disclose some of these factors and propose some solutions that may prove valuable at bridging the gap between preclinical findings and clinical trials.
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Affiliation(s)
- Rana Abdul Razzak
- Medical and Biological Sciences Building, School of Biology, University of St Andrews, St Andrews KY16 9TF, UK.
- Biomedical Science Research Centre, Schools of Chemistry and Biology, University of St Andrews, St Andrews KY16 9TF, UK.
| | - Gordon J Florence
- Biomedical Science Research Centre, Schools of Chemistry and Biology, University of St Andrews, St Andrews KY16 9TF, UK.
| | - Frank J Gunn-Moore
- Medical and Biological Sciences Building, School of Biology, University of St Andrews, St Andrews KY16 9TF, UK.
- Biomedical Science Research Centre, Schools of Chemistry and Biology, University of St Andrews, St Andrews KY16 9TF, UK.
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66
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Krammer EM, Prévost M. Function and Regulation of Acid Resistance Antiporters. J Membr Biol 2019; 252:465-481. [DOI: 10.1007/s00232-019-00073-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 06/08/2019] [Indexed: 01/07/2023]
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67
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Hall C, Wolfe H, Wells A, Chien HC, Colas C, Schlessinger A, Giacomini KM, Thomas AA. l-Type amino acid transporter 1 activity of 1,2,3-triazolyl analogs of l-histidine and l-tryptophan. Bioorg Med Chem Lett 2019; 29:2254-2258. [PMID: 31248771 DOI: 10.1016/j.bmcl.2019.06.033] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Revised: 06/12/2019] [Accepted: 06/19/2019] [Indexed: 01/03/2023]
Abstract
A series of 1,2,3-triazole analogs of the amino acids l-histidine and l-tryptophan were modeled, synthesized and tested for l-type amino acid transporter 1 (LAT1; SLC7A5) activity to guide the design of amino acid-drug conjugates (prodrugs). These triazoles were conveniently prepared by the highly convergent Huisgen 1,3-dipolar cycloaddition (Click Chemistry). Despite comparable predicted binding modes, triazoles generally demonstrated reduced cell uptake and LAT1 binding potency relative to their natural amino acid counterparts. The structure-activity relationship (SAR) data for these triazoles has important ramifications for treating cancer and brain disorders using amino acid prodrugs or LAT1 inhibitors.
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Affiliation(s)
- Colton Hall
- Department of Chemistry, University of Nebraska at Kearney, Kearney, NE 69949, USA
| | - Hannah Wolfe
- Department of Chemistry, University of Nebraska at Kearney, Kearney, NE 69949, USA
| | - Alyssa Wells
- Department of Chemistry, University of Nebraska at Kearney, Kearney, NE 69949, USA
| | - Huan-Chieh Chien
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Claire Colas
- Department of Pharmacological Sciences, Icahn School of Medicine at Mt. Sinai, New York, NY 10029, USA
| | - Avner Schlessinger
- Department of Pharmacological Sciences, Icahn School of Medicine at Mt. Sinai, New York, NY 10029, USA
| | - Kathleen M Giacomini
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Allen A Thomas
- Department of Chemistry, University of Nebraska at Kearney, Kearney, NE 69949, USA.
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68
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Torrecillas IR, Conde-Ceide S, de Lucas AI, Garcı́a Molina A, Trabanco AA, Lavreysen H, Pardo L, Tresadern G. Inhibition of the Alanine-Serine-Cysteine-1 Transporter by BMS-466442. ACS Chem Neurosci 2019; 10:2510-2517. [PMID: 30821959 DOI: 10.1021/acschemneuro.9b00019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Experiment and modeling were combined to understand inhibition of the alanine-serine-cysteine-1 (asc1) transporter. The structure-activity relationship (SAR) was explored with synthesis of analogues of BMS-466442. Direct target interaction and binding site location between TM helices 6 and 10 were confirmed via site directed mutagenesis. Computational modeling suggested the inhibitor binds via competitive occupation of the orthosteric site while also blocking the movement of TM helices that are required for transport.
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Affiliation(s)
- Ivan R. Torrecillas
- Laboratori de Medicina Computacional Unitat de Bioestadistica, Facultat de Medicina, Universitat Autonoma de Barcelona, 08193, Bellaterra, Spain
| | - Susana Conde-Ceide
- Medicinal Chemistry, Janssen Research & Development, Calle Jarama 75A, Toledo 45007, Spain
| | - Ana Isabel de Lucas
- Medicinal Chemistry, Janssen Research & Development, Calle Jarama 75A, Toledo 45007, Spain
| | | | - Andrés A. Trabanco
- Medicinal Chemistry, Janssen Research & Development, Calle Jarama 75A, Toledo 45007, Spain
| | | | - Leonardo Pardo
- Laboratori de Medicina Computacional Unitat de Bioestadistica, Facultat de Medicina, Universitat Autonoma de Barcelona, 08193, Bellaterra, Spain
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69
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Fotiadis D, Jeckelmann JM. The structure of the human 4F2hc-LAT1 heteromeric amino acid transporter. SCIENCE CHINA-LIFE SCIENCES 2019; 62:848-850. [DOI: 10.1007/s11427-019-9558-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Accepted: 04/20/2019] [Indexed: 12/13/2022]
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70
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Grafted hyaluronic acid N-acetyl-l-methionine for targeting of LAT1 receptor: In-silico, synthesis and microscale thermophoresis studies. Int J Biol Macromol 2019; 125:767-777. [PMID: 30553855 DOI: 10.1016/j.ijbiomac.2018.12.104] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 11/29/2018] [Accepted: 12/12/2018] [Indexed: 11/20/2022]
Abstract
Neutral amino acids can be delivered into cells through the l-type amino acid transporter-1 (LAT1), which is a sodium independent transporter. The LAT1 protein is expressed in different tissues, including kidney, blood brain barrier and intestinal wall hence LAT1 can be used as a target in diseases associated with its overexpression. In-silico interactions between different ligands, including methionine (Met), N-acetyl-l-methionine (AcMet), hyaluronic acid (HA), grafted hyaluronic-acid l-methionine (HA-ADH-Met) and a novel grafted hyaluronic acid-N-acetyl-l-methionine (HA-ADH-AcMet), which are at the active site of the LAT1 transporter, were studied and the binding energies calculated. The HA-ADH-AcMet complex demonstrated binding energy and solvation energy of -74.84 and 81.46 kcal/mol, respectively, thus validating its potential to be synthesized. The structural conformation of the HA-ADH-AcMet was confirmed using 1H NMR, FTIR, DSC and PXRD. Microscale thermophoresis was employed to study the binding affinity between the different ligands and LAT1. The binding affinity was expressed in terms of a dissociation constant (Kd), where that of HA-ADH-AcMet was found to be 408 nM which was considered the strongest among the different ligands tested. HA-ADH-AcMet can be used as a targeting moiety for development of medicines to treat different diseases and processes that express LAT1 protein.
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71
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Al-Abdulla R, Perez-Silva L, Abete L, Romero MR, Briz O, Marin JJG. Unraveling ‘The Cancer Genome Atlas’ information on the role of SLC transporters in anticancer drug uptake. Expert Rev Clin Pharmacol 2019; 12:329-341. [DOI: 10.1080/17512433.2019.1581605] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Ruba Al-Abdulla
- Experimental Hepatology and Drug Targeting (HEVEFARM), University of Salamanca, IBSAL, Salamanca, Spain
| | - Laura Perez-Silva
- Experimental Hepatology and Drug Targeting (HEVEFARM), University of Salamanca, IBSAL, Salamanca, Spain
| | - Lorena Abete
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy
| | - Marta R. Romero
- Experimental Hepatology and Drug Targeting (HEVEFARM), University of Salamanca, IBSAL, Salamanca, Spain
- Center for the Study of Liver and Gastrointestinal Diseases (CIBERehd), Carlos III National Institute of Health, Madrid, Spain
| | - Oscar Briz
- Experimental Hepatology and Drug Targeting (HEVEFARM), University of Salamanca, IBSAL, Salamanca, Spain
- Center for the Study of Liver and Gastrointestinal Diseases (CIBERehd), Carlos III National Institute of Health, Madrid, Spain
| | - Jose J. G. Marin
- Experimental Hepatology and Drug Targeting (HEVEFARM), University of Salamanca, IBSAL, Salamanca, Spain
- Center for the Study of Liver and Gastrointestinal Diseases (CIBERehd), Carlos III National Institute of Health, Madrid, Spain
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72
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Bartoccioni P, Fort J, Zorzano A, Errasti-Murugarren E, Palacín M. Functional characterization of the alanine-serine-cysteine exchanger of Carnobacterium sp AT7. J Gen Physiol 2019; 151:505-517. [PMID: 30696726 PMCID: PMC6445583 DOI: 10.1085/jgp.201812195] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 11/16/2018] [Accepted: 01/03/2019] [Indexed: 01/18/2023] Open
Abstract
Proteins of the L-type amino acid transporter (LAT) subfamily take up amino acids from the environment for use in the cell. Bartoccioni et al. show that the bacterial amino acid exchanger BasC is functionally similar to the human LAT Asc1, making BasC a useful model for this class of transporters. Many key cell processes require prior cell uptake of amino acids from the environment, which is facilitated by cell membrane amino acid transporters such as those of the L-type amino acid transporter (LAT) subfamily. Alterations in LAT subfamily amino acid transport are associated with several human diseases, including cancer, aminoacidurias, and neurodegenerative conditions. Therefore, from the perspective of human health, there is considerable interest in obtaining structural information about these transporter proteins. We recently solved the crystal structure of the first LAT transporter, the bacterial alanine-serine-cysteine exchanger of Carnobacterium sp AT7 (BasC). Here, we provide a complete functional characterization of detergent-purified, liposome-reconstituted BasC transporter to allow the extension of the structural insights into mechanistic understanding. BasC is a sodium- and proton-independent small neutral amino acid exchanger whose substrate and inhibitor selectivity are almost identical to those previously described for the human LAT subfamily member Asc-1. Additionally, we show that, like its human counterparts, this transporter has apparent affinity asymmetry for the intra- and extracellular substrate binding sites—a key feature in the physiological role played by these proteins. BasC is an excellent paradigm of human LAT transporters and will contribute to our understanding of the molecular mechanisms underlying substrate recognition and translocation at both sides of the plasma membrane.
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Affiliation(s)
- Paola Bartoccioni
- Institute for Research in Biomedicine, Barcelona Institute of Science and Technology, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras, Barcelona, Spain
| | - Joana Fort
- Institute for Research in Biomedicine, Barcelona Institute of Science and Technology, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Enfermedades Raras, Barcelona, Spain.,Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Antonio Zorzano
- Institute for Research in Biomedicine, Barcelona Institute of Science and Technology, Barcelona, Spain.,Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas, Barcelona, Spain
| | - Ekaitz Errasti-Murugarren
- Institute for Research in Biomedicine, Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Manuel Palacín
- Institute for Research in Biomedicine, Barcelona Institute of Science and Technology, Barcelona, Spain .,Centro de Investigación Biomédica en Red de Enfermedades Raras, Barcelona, Spain.,Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, University of Barcelona, Barcelona, Spain
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73
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Nodwell MB, Yang H, Merkens H, Malik N, Čolović M, Björn Wagner, Martin RE, Bénard F, Schaffer P, Britton R. 18F-Branched-Chain Amino Acids: Structure-Activity Relationships and PET Imaging Potential. J Nucl Med 2019; 60:1003-1009. [PMID: 30683769 DOI: 10.2967/jnumed.118.220483] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 11/30/2018] [Indexed: 11/16/2022] Open
Abstract
The large, neutral L-type amino acid transporters (LAT1-LAT4) are sodium-independent transporters that are widely distributed throughout the body. LAT expression levels are increased in many types of cancer, and their expression increases as cancers progress, leading to high expression levels in high-grade tumors and metastases. Because of the key role and overexpression of LAT in many types of cancer, radiolabeled LAT substrates are promising candidates for nuclear imaging of malignancies that are not well revealed by conventional radiotracers. The goal of this study was to examine the structure-activity relationships of a series of 18F-labeled amino acids that were predicted to be substrates of the LAT transport system. Methods: Using a photocatalytic radical fluorination, we prepared a series of 11 fluorinated branched-chain amino acids and evaluated them and their nonfluorinated parents in a cell-based LAT affinity assay. We radiofluorinated selected branched-chain amino acids via the same radical fluorination reaction and evaluated tumor uptake in U-87 glioma xenograft-bearing mice. Results: Structure-activity relationship trends observed in a LAT affinity assay were maintained in further in vitro studies, as well as in vivo using a U-87 xenograft model. LAT1 uptake was tolerant of fluorinated amino acid stereochemistry and chain length. PET imaging and biodistribution studies showed that the tracer (S)-5-18F-fluorohomoleucine had rapid tumor uptake, favorable in vivo kinetics, and good stability. Conclusion: By using an in vitro affinity assay, we could predict LAT-mediated cancer cell uptake in a panel of fluorinated amino acids. These predictions were consistent when applied to different cell lines and murine tumor models, and several new tracers may be suitable for further development as oncologic PET imaging agents.
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Affiliation(s)
- Matthew B Nodwell
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Hua Yang
- Life Sciences Division, TRIUMF, Vancouver, British Columbia, Canada
| | - Helen Merkens
- Department of Molecular Oncology, BC Cancer Agency, Vancouver, British Columbia, Canada.,Department of Radiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Noeen Malik
- Life Sciences Division, TRIUMF, Vancouver, British Columbia, Canada.,Department of Molecular Oncology, BC Cancer Agency, Vancouver, British Columbia, Canada
| | - Milena Čolović
- Department of Molecular Oncology, BC Cancer Agency, Vancouver, British Columbia, Canada.,Department of Radiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Björn Wagner
- Pharmaceutical Sciences, Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland; and
| | - Rainer E Martin
- Medicinal Chemistry, Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
| | - François Bénard
- Department of Molecular Oncology, BC Cancer Agency, Vancouver, British Columbia, Canada.,Department of Radiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Paul Schaffer
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, Canada.,Life Sciences Division, TRIUMF, Vancouver, British Columbia, Canada.,Department of Radiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Robert Britton
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, Canada
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74
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Nogara PA, Oliveira CS, Schmitz GL, Piquini PC, Farina M, Aschner M, Rocha JBT. Methylmercury's chemistry: From the environment to the mammalian brain. Biochim Biophys Acta Gen Subj 2019; 1863:129284. [PMID: 30659885 DOI: 10.1016/j.bbagen.2019.01.006] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2018] [Revised: 12/14/2018] [Accepted: 01/09/2019] [Indexed: 02/06/2023]
Abstract
Methylmercury is a neurotoxicant that is found in fish and rice. MeHg's toxicity is mediated by blockage of -SH and -SeH groups of proteins. However, the identification of MeHg's targets is elusive. Here we focus on the chemistry of MeHg in the abiotic and biotic environment. The toxicological chemistry of MeHg is complex in metazoans, but at the atomic level it can be explained by exchange reactions of MeHg bound to -S(e)H with another free -S(e)H group (R1S(e)-HgMe + R2-S(e)H ↔ R1S(e)H + R2-S(e)-HgMe). This reaction was first studied by professor Rabenstein and here it is referred as the "Rabenstein's Reaction". The absorption, distribution, and excretion of MeHg in the environment and in the body of animals will be dictated by Rabenstein's reactions. The affinity of MeHg by thiol and selenol groups and the exchange of MeHg by Rabenstein's Reaction (which is a diffusion controlled reaction) dictates MeHg's neurotoxicity. However, it is important to emphasize that the MeHg exchange reaction velocity with different types of thiol- and selenol-containing proteins will also depend on protein-specific structural and thermodynamical factors. New experimental approaches and detailed studies about the Rabenstein's reaction between MeHg with low molecular mass thiol (LMM-SH) molecules (cysteine, GSH, acetyl-CoA, lipoate, homocysteine) with abundant high molecular mass thiol (HMM-SH) molecules (albumin, hemoglobin) and HMM-SeH (GPxs, Selenoprotein P, TrxR1-3) are needed. The study of MeHg migration from -S(e)-Hg- bonds to free -S(e)H groups (Rabenstein's Reaction) in pure chemical systems and neural cells (with special emphasis to the LMM-SH and HMM-S(e)H molecules cited above) will be critical to developing realistic constants to be used in silico models that will predict the distribution of MeHg in humans.
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Affiliation(s)
- Pablo A Nogara
- Departamento de Bioquímica e Biologia Molecular, CCNE, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Cláudia S Oliveira
- Departamento de Bioquímica e Biologia Molecular, CCNE, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Gabriela L Schmitz
- Departamento de Bioquímica e Biologia Molecular, CCNE, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Paulo C Piquini
- Departamento de Física, CCNE, Universidade Federal de Santa Maria (UFSM), Santa Maria, RS, Brazil
| | - Marcelo Farina
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - João B T Rocha
- Departamento de Bioquímica e Biologia Molecular, CCNE, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil.
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Gonzalez-Carter DA, Ong ZY, McGilvery CM, Dunlop IE, Dexter DT, Porter AE. L-DOPA functionalized, multi-branched gold nanoparticles as brain-targeted nano-vehicles. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2019; 15:1-11. [DOI: 10.1016/j.nano.2018.08.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 08/08/2018] [Accepted: 08/19/2018] [Indexed: 12/12/2022]
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76
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Young TL, Zychowski KE, Denson JL, Campen MJ. Blood-brain barrier at the interface of air pollution-associated neurotoxicity and neuroinflammation. ROLE OF INFLAMMATION IN ENVIRONMENTAL NEUROTOXICITY 2019. [DOI: 10.1016/bs.ant.2018.10.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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77
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Singh N, Scalise M, Galluccio M, Wieder M, Seidel T, Langer T, Indiveri C, Ecker GF. Discovery of Potent Inhibitors for the Large Neutral Amino Acid Transporter 1 (LAT1) by Structure-Based Methods. Int J Mol Sci 2018; 20:ijms20010027. [PMID: 30577601 PMCID: PMC6337383 DOI: 10.3390/ijms20010027] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 12/11/2018] [Accepted: 12/15/2018] [Indexed: 12/20/2022] Open
Abstract
The large neutral amino acid transporter 1 (LAT1) is a promising anticancer target that is required for the cellular uptake of essential amino acids that serve as building blocks for cancer growth and proliferation. Here, we report a structure-based approach to identify chemically diverse and potent inhibitors of LAT1. First, a homology model of LAT1 that is based on the atomic structures of the prokaryotic homologs was constructed. Molecular docking of nitrogen mustards (NMs) with a wide range of affinity allowed for deriving a common binding mode that could explain the structure−activity relationship pattern in NMs. Subsequently, validated binding hypotheses were subjected to molecular dynamics simulation, which allowed for extracting a set of dynamic pharmacophores. Finally, a library of ~1.1 million molecules was virtually screened against these pharmacophores, followed by docking. Biological testing of the 30 top-ranked hits revealed 13 actives, with the best compound showing an IC50 value in the sub-μM range.
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Affiliation(s)
- Natesh Singh
- Department of Pharmaceutical Chemistry, University of Vienna, Althanstrasse 14, 1090 Wien, Austria.
| | - Mariafrancesca Scalise
- Department DiBEST, Unit of Biochemistry & Molecular Biotechnology, University of Calabria, Via P. Bucci 4C, 87036 Arcavacata di Rende, Italy.
| | - Michele Galluccio
- Department DiBEST, Unit of Biochemistry & Molecular Biotechnology, University of Calabria, Via P. Bucci 4C, 87036 Arcavacata di Rende, Italy.
| | - Marcus Wieder
- Department of Pharmaceutical Chemistry, University of Vienna, Althanstrasse 14, 1090 Wien, Austria.
| | - Thomas Seidel
- Department of Pharmaceutical Chemistry, University of Vienna, Althanstrasse 14, 1090 Wien, Austria.
| | - Thierry Langer
- Department of Pharmaceutical Chemistry, University of Vienna, Althanstrasse 14, 1090 Wien, Austria.
| | - Cesare Indiveri
- Department DiBEST, Unit of Biochemistry & Molecular Biotechnology, University of Calabria, Via P. Bucci 4C, 87036 Arcavacata di Rende, Italy.
| | - Gerhard F Ecker
- Department of Pharmaceutical Chemistry, University of Vienna, Althanstrasse 14, 1090 Wien, Austria.
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78
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Mendes M, Sousa JJ, Pais A, Vitorino C. Targeted Theranostic Nanoparticles for Brain Tumor Treatment. Pharmaceutics 2018; 10:E181. [PMID: 30304861 PMCID: PMC6321593 DOI: 10.3390/pharmaceutics10040181] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 09/21/2018] [Accepted: 09/27/2018] [Indexed: 12/13/2022] Open
Abstract
The poor prognosis and rapid recurrence of glioblastoma (GB) are associated to its fast-growing process and invasive nature, which make difficult the complete removal of the cancer infiltrated tissues. Additionally, GB heterogeneity within and between patients demands a patient-focused method of treatment. Thus, the implementation of nanotechnology is an attractive approach considering all anatomic issues of GB, since it will potentially improve brain drug distribution, due to the interaction between the blood⁻brain barrier and nanoparticles (NPs). In recent years, theranostic techniques have also been proposed and regarded as promising. NPs are advantageous for this application, due to their respective size, easy surface modification and versatility to integrate multiple functional components in one system. The design of nanoparticles focused on therapeutic and diagnostic applications has increased exponentially for the treatment of cancer. This dual approach helps to understand the location of the tumor tissue, the biodistribution of nanoparticles, the progress and efficacy of the treatment, and is highly useful for personalized medicine-based therapeutic interventions. To improve theranostic approaches, different active strategies can be used to modulate the surface of the nanotheranostic particle, including surface markers, proteins, drugs or genes, and take advantage of the characteristics of the microenvironment using stimuli responsive triggers. This review focuses on the different strategies to improve the GB treatment, describing some cell surface markers and their ligands, and reports some strategies, and their efficacy, used in the current research.
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Affiliation(s)
- Maria Mendes
- Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal.
- Center for Neurosciences and Cell Biology (CNC), University of Coimbra, 3004-504 Coimbra, Portugal.
| | - João José Sousa
- Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal.
- LAQV, REQUIMTE, Group of Pharmaceutical Technology, 3000-548 Coimbra, Portugal.
| | - Alberto Pais
- Coimbra Chemistry Centre, Department of Chemistry, University of Coimbra, 3004-535 Coimbra, Portugal.
| | - Carla Vitorino
- Faculty of Pharmacy, University of Coimbra, 3000-548 Coimbra, Portugal.
- Center for Neurosciences and Cell Biology (CNC), University of Coimbra, 3004-504 Coimbra, Portugal.
- LAQV, REQUIMTE, Group of Pharmaceutical Technology, 3000-548 Coimbra, Portugal.
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79
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Fuchs R, Stracke A, Holzmann V, Luschin-Ebengreuth G, Meier-Allard N, Ebner N, Lassacher TM, Absenger-Novak M, Fröhlich E, Schittmayer M, Cano Crespo S, Palacin M, Rinner B, Birner-Gruenberger R. Prazosin induced lysosomal tubulation interferes with cytokinesis and the endocytic sorting of the tumour antigen CD98hc. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2018; 1865:1211-1229. [PMID: 29909287 PMCID: PMC6070144 DOI: 10.1016/j.bbamcr.2018.06.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 05/28/2018] [Accepted: 06/12/2018] [Indexed: 11/29/2022]
Abstract
The quinazoline based drug prazosin (PRZ) is a potent inducer of apoptosis in human cancer cells. We recently reported that PRZ enters cells via endocytosis and induces tubulation of the endolysosomal system. In a proteomics approach aimed at identifying potential membrane proteins with binding affinity to quinazolines, we detected the oncoprotein CD98hc. We confirmed shuttling of CD98hc towards lysosomes and upregulation of CD98hc expression in PRZ treated cells. Gene knockout (KO) experiments revealed that endocytosis of PRZ still occurs in the absence of CD98hc - suggesting that PRZ does not enter the cell via CD98hc but misroutes the protein towards tubular lysosomes. Lysosomal tubulation interfered with completion of cytokinesis and provoked endoreplication. CD98hc KO cells showed reduced endoreplication capacity and lower sensitivity towards PRZ induced apoptosis than wild type cells. Thus, loss of CD98hc does not affect endocytosis of PRZ and lysosomal tubulation, but the ability for endoreplication and survival of cells. Furthermore, we found that glutamine, lysomototropic agents - namely chloroquine and NH4Cl - as well as inhibition of v-ATPase, interfere with the intracellular transport of CD98hc. In summary, our study further emphasizes lysosomes as target organelles to inhibit proliferation and to induce cell death in cancer. Most importantly, we demonstrate for the first time that the intracellular trafficking of CD98hc can be modulated by small molecules. Since CD98hc is considered as a potential drug target in several types of human malignancies, our study possesses translational significance suggesting, that old drugs are able to act on a novel target.
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Affiliation(s)
- Robert Fuchs
- Chair of Immunology and Pathophysiology, Otto Loewi Research Center, Medical University of Graz, Heinrichstraße 31, 8010 Graz, Austria.
| | - Anika Stracke
- Chair of Immunology and Pathophysiology, Otto Loewi Research Center, Medical University of Graz, Heinrichstraße 31, 8010 Graz, Austria
| | - Viktoria Holzmann
- Chair of Immunology and Pathophysiology, Otto Loewi Research Center, Medical University of Graz, Heinrichstraße 31, 8010 Graz, Austria; FH JOANNEUM - University of Applied Sciences, Alte Poststraße 149, 8020 Graz, Austria
| | - Gerfried Luschin-Ebengreuth
- Chair of Immunology and Pathophysiology, Otto Loewi Research Center, Medical University of Graz, Heinrichstraße 31, 8010 Graz, Austria
| | - Nathalie Meier-Allard
- Chair of Immunology and Pathophysiology, Otto Loewi Research Center, Medical University of Graz, Heinrichstraße 31, 8010 Graz, Austria
| | - Nadine Ebner
- Chair of Immunology and Pathophysiology, Otto Loewi Research Center, Medical University of Graz, Heinrichstraße 31, 8010 Graz, Austria
| | - Teresa Maria Lassacher
- Chair of Immunology and Pathophysiology, Otto Loewi Research Center, Medical University of Graz, Heinrichstraße 31, 8010 Graz, Austria
| | - Markus Absenger-Novak
- Centre for Medical Research, Medical University of Graz, Stiftingtalstrasse 24, 8010 Graz, Austria
| | - Eleonore Fröhlich
- Centre for Medical Research, Medical University of Graz, Stiftingtalstrasse 24, 8010 Graz, Austria
| | - Matthias Schittmayer
- Research Unit Functional Proteomics and Metabolic Pathways, Institute of Pathology, Medical University of Graz, Auenbruggerplatz 25, 8036 Graz, Austria; Omics Center Graz, BioTechMed-Graz, Stiftingtalstrasse 24, 8010 Graz, Austria
| | - Sara Cano Crespo
- Institute for Research in Biomedicine (IRB-Barcelona), Barcelona Institute of Science and Technology (BIST), Department of Biochemistry and Molecular Biomedicine, University of Barcelona, and CIBERER, Parc Científic de Barcelona. Baldiri I Reixac 10-12, 08028 Barcelona, Spain
| | - Manuel Palacin
- Institute for Research in Biomedicine (IRB-Barcelona), Barcelona Institute of Science and Technology (BIST), Department of Biochemistry and Molecular Biomedicine, University of Barcelona, and CIBERER, Parc Científic de Barcelona. Baldiri I Reixac 10-12, 08028 Barcelona, Spain
| | - Beate Rinner
- Biomedical Research, Medical University of Graz, Roseggerweg 48, 8036 Graz, Austria
| | - Ruth Birner-Gruenberger
- Research Unit Functional Proteomics and Metabolic Pathways, Institute of Pathology, Medical University of Graz, Auenbruggerplatz 25, 8036 Graz, Austria; Omics Center Graz, BioTechMed-Graz, Stiftingtalstrasse 24, 8010 Graz, Austria
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80
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Kandasamy P, Gyimesi G, Kanai Y, Hediger MA. Amino acid transporters revisited: New views in health and disease. Trends Biochem Sci 2018; 43:752-789. [PMID: 30177408 DOI: 10.1016/j.tibs.2018.05.003] [Citation(s) in RCA: 263] [Impact Index Per Article: 43.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Revised: 05/23/2018] [Accepted: 05/25/2018] [Indexed: 02/09/2023]
Abstract
Amino acid transporters (AATs) are membrane-bound transport proteins that mediate transfer of amino acids into and out of cells or cellular organelles. AATs have diverse functional roles ranging from neurotransmission to acid-base balance, intracellular energy metabolism, and anabolic and catabolic reactions. In cancer cells and diabetes, dysregulation of AATs leads to metabolic reprogramming, which changes intracellular amino acid levels, contributing to the pathogenesis of cancer, obesity and diabetes. Indeed, the neutral amino acid transporters (NATs) SLC7A5/LAT1 and SLC1A5/ASCT2 are likely involved in several human malignancies. However, a clinical therapy that directly targets AATs has not yet been developed. The purpose of this review is to highlight the structural and functional diversity of AATs, their diverse physiological roles in different tissues and organs, their wide-ranging implications in human diseases and the emerging strategies and tools that will be necessary to target AATs therapeutically.
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Affiliation(s)
- Palanivel Kandasamy
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, CH-3012 Bern, Switzerland
| | - Gergely Gyimesi
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, CH-3012 Bern, Switzerland
| | - Yoshikatsu Kanai
- Division of Bio-system Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan.
| | - Matthias A Hediger
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, CH-3012 Bern, Switzerland.
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81
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Palazzolo L, Parravicini C, Laurenzi T, Guerrini U, Indiveri C, Gianazza E, Eberini I. In silico Description of LAT1 Transport Mechanism at an Atomistic Level. Front Chem 2018; 6:350. [PMID: 30197880 PMCID: PMC6117385 DOI: 10.3389/fchem.2018.00350] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 07/25/2018] [Indexed: 11/24/2022] Open
Abstract
The molecular mechanism of transport mediated by LAT1, a sodium-independent antiporter of large neutral amino acids, was investigated through in silico procedures, specifically making reference to two transported substrates, tyrosine (Tyr) and leucine methyl ester (LME), and to 3,5-diiodo-L-tyrosine (DIT), a well-known LAT1 inhibitor. Two models of the transporter were built by comparative modeling, with LAT1 either in an outward-facing (OF) or in an inward-facing (IF) conformation, based, respectively, on the crystal structure of AdiC and of GadC. As frequently classic Molecular Dynamics (MD) fails to monitor large-scale conformational transitions within a reasonable simulated time, the OF structure was equilibrated for 150 ns then processed through targeted MD (tMD). During this procedure, an elastic force pulled the OF structure to the IF structure and induced, at the same time, substrates/inhibitor to move through the transport channel. This elastic force was modulated by a spring constant (k) value; by decreasing its value from 100 to 70, it was possible to comparatively account for the propensity for transport of the three tested molecules. In line with our expectations, during the tMD simulations, Tyr and LME behaved as substrates, moving down the transport channel, or most of it, for all k values. On the contrary, DIT behaved as an inhibitor, being (almost) transported across the channel only at the highest k value (100). During their transit through the channel, Tyr and LME interacted with specific amino acids (first with Phe252 then with Thr345, Arg348, Tyr259, and Phe262); this suggests that a primary as well as a putative secondary gate may contribute to the transport of substrates. Quite on the opposite, DIT appeared to establish only transient interactions with side chains lining the external part of the transport channel. Our tMD simulations could thus efficiently discriminate between two transported substrates and one inhibitor, and therefore can be proposed as a benchmark for developing novel LAT1 inhibitors of pharmacological interest.
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Affiliation(s)
- Luca Palazzolo
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - Chiara Parravicini
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - Tommaso Laurenzi
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - Uliano Guerrini
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - Cesare Indiveri
- Dipartimento di Biologia, Ecologia e Scienze della Terra, University of Calabria, Cosenza, Italy
| | - Elisabetta Gianazza
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
| | - Ivano Eberini
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milan, Italy
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82
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Chien HC, Colas C, Finke K, Springer S, Stoner L, Zur AA, Venteicher B, Campbell J, Hall C, Flint A, Augustyn E, Hernandez C, Heeren N, Hansen L, Anthony A, Bauer J, Fotiadis D, Schlessinger A, Giacomini KM, Thomas AA. Reevaluating the Substrate Specificity of the L-Type Amino Acid Transporter (LAT1). J Med Chem 2018; 61:7358-7373. [PMID: 30048132 DOI: 10.1021/acs.jmedchem.8b01007] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The L-type amino acid transporter 1 (LAT1, SLC7A5) transports essential amino acids across the blood-brain barrier (BBB) and into cancer cells. To utilize LAT1 for drug delivery, potent amino acid promoieties are desired, as prodrugs must compete with millimolar concentrations of endogenous amino acids. To better understand ligand-transporter interactions that could improve potency, we developed structural LAT1 models to guide the design of substituted analogues of phenylalanine and histidine. Furthermore, we evaluated the structure-activity relationship (SAR) for both enantiomers of naturally occurring LAT1 substrates. Analogues were tested in cis-inhibition and trans-stimulation cell assays to determine potency and uptake rate. Surprisingly, LAT1 can transport amino acid-like substrates with wide-ranging polarities including those containing ionizable substituents. Additionally, the rate of LAT1 transport was generally nonstereoselective even though enantiomers likely exhibit different binding modes. Our findings have broad implications to the development of new treatments for brain disorders and cancer.
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Affiliation(s)
- Huan-Chieh Chien
- Department of Bioengineering and Therapeutic Sciences , University of California, San Francisco , San Francisco , California 94158 , United States
| | - Claire Colas
- Department of Pharmacological Sciences , Icahn School of Medicine at Mount Sinai , New York , New York 10029 , United States
| | - Karissa Finke
- Department of Chemistry , University of Nebraska at Kearney , Kearney , Nebraska 68849 , United States
| | - Seth Springer
- Department of Chemistry , University of Nebraska at Kearney , Kearney , Nebraska 68849 , United States
| | - Laura Stoner
- Department of Chemistry , University of Nebraska at Kearney , Kearney , Nebraska 68849 , United States
| | - Arik A Zur
- Department of Bioengineering and Therapeutic Sciences , University of California, San Francisco , San Francisco , California 94158 , United States
| | - Brooklynn Venteicher
- Department of Chemistry , University of Nebraska at Kearney , Kearney , Nebraska 68849 , United States
| | - Jerome Campbell
- Department of Chemistry , University of Nebraska at Kearney , Kearney , Nebraska 68849 , United States
| | - Colton Hall
- Department of Chemistry , University of Nebraska at Kearney , Kearney , Nebraska 68849 , United States
| | - Andrew Flint
- Department of Chemistry , University of Nebraska at Kearney , Kearney , Nebraska 68849 , United States
| | - Evan Augustyn
- Department of Chemistry , University of Nebraska at Kearney , Kearney , Nebraska 68849 , United States
| | - Christopher Hernandez
- Department of Chemistry , University of Nebraska at Kearney , Kearney , Nebraska 68849 , United States
| | - Nathan Heeren
- Department of Chemistry , University of Nebraska at Kearney , Kearney , Nebraska 68849 , United States
| | - Logan Hansen
- Department of Chemistry , University of Nebraska at Kearney , Kearney , Nebraska 68849 , United States
| | - Abby Anthony
- Department of Chemistry , University of Nebraska at Kearney , Kearney , Nebraska 68849 , United States
| | - Justine Bauer
- Department of Chemistry , University of Nebraska at Kearney , Kearney , Nebraska 68849 , United States
| | - Dimitrios Fotiadis
- Institute of Biochemistry and Molecular Medicine, and Swiss National Centre of Competence in Research (NCCR) TransCure , University of Bern , 3012 Bern , Switzerland
| | - Avner Schlessinger
- Department of Pharmacological Sciences , Icahn School of Medicine at Mount Sinai , New York , New York 10029 , United States
| | - Kathleen M Giacomini
- Department of Bioengineering and Therapeutic Sciences , University of California, San Francisco , San Francisco , California 94158 , United States
| | - Allen A Thomas
- Department of Chemistry , University of Nebraska at Kearney , Kearney , Nebraska 68849 , United States
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83
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Scalise M, Galluccio M, Console L, Pochini L, Indiveri C. The Human SLC7A5 (LAT1): The Intriguing Histidine/Large Neutral Amino Acid Transporter and Its Relevance to Human Health. Front Chem 2018; 6:243. [PMID: 29988369 PMCID: PMC6023973 DOI: 10.3389/fchem.2018.00243] [Citation(s) in RCA: 179] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 06/06/2018] [Indexed: 12/22/2022] Open
Abstract
SLC7A5, known as LAT1, belongs to the APC superfamily and forms a heterodimeric amino acid transporter interacting with the glycoprotein CD98 (SLC3A2) through a conserved disulfide. The complex is responsible for uptake of essential amino acids in crucial body districts such as placenta and blood brain barrier. LAT1/CD98 heterodimer has been studied over the years to unravel the transport mechanism and the role of each subunit. Studies conducted in intact cells demonstrated that LAT1/CD98 mediates a Na+ and pH independent antiport of amino acids. Some novel insights into the function of LAT1 derived from studies conducted in proteoliposomes reconstituted with the recombinant human LAT1. Using this experimental tool, it has been demonstrated that the preferred substrate is histidine and that CD98 is not required for transport being, plausibly, involved in routing LAT1 to the plasma membrane. Since a 3D structure of LAT1 is not available, homology models have been built on the basis of the AdiC transporter from E.coli. Crucial residues for substrate recognition and gating have been identified using a combined approach of bioinformatics and site-directed mutagenesis coupled to functional assays. Over the years, the interest around LAT1 increased because this transporter is involved in important human diseases such as neurological disorders and cancer. Therefore, LAT1 became an important pharmacological target together with other nutrient membrane transporters. Moving from knowledge on structure/function relationships, two cysteine residues, lying on the substrate binding site, have been exploited for designing thiol reacting covalent inhibitors. Some lead compounds have been characterized whose efficacy has been tested in a cancer cell line.
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Affiliation(s)
- Mariafrancesca Scalise
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia, Ecologia, Scienze della Terra), University of Calabria, Rende, Italy
| | - Michele Galluccio
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia, Ecologia, Scienze della Terra), University of Calabria, Rende, Italy
| | - Lara Console
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia, Ecologia, Scienze della Terra), University of Calabria, Rende, Italy
| | - Lorena Pochini
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia, Ecologia, Scienze della Terra), University of Calabria, Rende, Italy
| | - Cesare Indiveri
- Unit of Biochemistry and Molecular Biotechnology, Department DiBEST (Biologia, Ecologia, Scienze della Terra), University of Calabria, Rende, Italy.,CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnology, Bari, Italy
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84
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Kärkkäinen J, Gynther M, Kokkola T, Petsalo A, Auriola S, Lahtela-Kakkonen M, Laine K, Rautio J, Huttunen KM. Structural properties for selective and efficient l-type amino acid transporter 1 (LAT1) mediated cellular uptake. Int J Pharm 2018; 544:91-99. [DOI: 10.1016/j.ijpharm.2018.04.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 04/13/2018] [Accepted: 04/13/2018] [Indexed: 12/24/2022]
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85
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Singh N, Ecker GF. Insights into the Structure, Function, and Ligand Discovery of the Large Neutral Amino Acid Transporter 1, LAT1. Int J Mol Sci 2018; 19:E1278. [PMID: 29695141 PMCID: PMC5983779 DOI: 10.3390/ijms19051278] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 04/18/2018] [Accepted: 04/19/2018] [Indexed: 12/31/2022] Open
Abstract
The large neutral amino acid transporter 1 (LAT1, or SLC7A5) is a sodium- and pH-independent transporter, which supplies essential amino acids (e.g., leucine, phenylalanine) to cells. It plays an important role at the Blood⁻Brain Barrier (BBB) where it facilitates the transport of thyroid hormones, pharmaceuticals (e.g., l-DOPA, gabapentin), and metabolites into the brain. Moreover, its expression is highly upregulated in various types of human cancer that are characterized by an intense demand for amino acids for growth and proliferation. Therefore, LAT1 is believed to be an important drug target for cancer treatment. With the crystallization of the arginine/agmatine antiporter (AdiC) from Escherichia Coli, numerous homology models of LAT1 have been built to elucidate the substrate binding site, ligand⁻transporter interaction, and structure⁻function relationship. The use of these models in combination with molecular docking and experimental testing has identified novel chemotypes of ligands of LAT1. Here, we highlight the structure, function, transport mechanism, and homology modeling of LAT1. Additionally, results from structure⁻function studies performed on LAT1 are addressed, which have enhanced our knowledge of the mechanism of substrate binding and translocation. This is followed by a discussion on ligand- and structure-based approaches, with an emphasis on elucidating the molecular basis of LAT1 inhibition. Finally, we provide an exhaustive summary of different LAT1 inhibitors that have been identified so far, including the recently discovered irreversible covalent inhibitors.
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Affiliation(s)
- Natesh Singh
- Department of Pharmaceutical Chemistry, University of Vienna, Althanstrasse 14, 1090 Wien, Austria.
| | - Gerhard F Ecker
- Department of Pharmaceutical Chemistry, University of Vienna, Althanstrasse 14, 1090 Wien, Austria.
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86
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Ilgü H, Jeckelmann JM, Colas C, Ucurum Z, Schlessinger A, Fotiadis D. Effects of Mutations and Ligands on the Thermostability of the l-Arginine/Agmatine Antiporter AdiC and Deduced Insights into Ligand-Binding of Human l-Type Amino Acid Transporters. Int J Mol Sci 2018; 19:ijms19030918. [PMID: 29558430 PMCID: PMC5877779 DOI: 10.3390/ijms19030918] [Citation(s) in RCA: 12] [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: 02/11/2018] [Revised: 03/14/2018] [Accepted: 03/15/2018] [Indexed: 01/09/2023] Open
Abstract
The l-arginine/agmatine transporter AdiC is a prokaryotic member of the SLC7 family, which enables pathogenic enterobacteria to survive the extremely acidic gastric environment. Wild-type AdiC from Escherichia coli, as well as its previously reported point mutants N22A and S26A, were overexpressed homologously and purified to homogeneity. A size-exclusion chromatography-based thermostability assay was used to determine the melting temperatures (Tms) of the purified AdiC variants in the absence and presence of the selected ligands l-arginine (Arg), agmatine, l-arginine methyl ester, and l-arginine amide. The resulting Tms indicated stabilization of AdiC variants upon ligand binding, in which Tms and ligand binding affinities correlated positively. Considering results from this and previous studies, we revisited the role of AdiC residue S26 in Arg binding and proposed interactions of the α-carboxylate group of Arg exclusively with amide groups of the AdiC backbone. In the context of substrate binding in the human SLC7 family member l-type amino acid transporter-1 (LAT1; SLC7A5), an analogous role of S66 in LAT1 to S26 in AdiC is discussed based on homology modeling and amino acid sequence analysis. Finally, we propose a binding mechanism for l-amino acid substrates to LATs from the SLC7 family.
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Affiliation(s)
- Hüseyin Ilgü
- Institute of Biochemistry and Molecular Medicine, and Swiss National Centre of Competence in Research (NCCR) TransCure, University of Bern, CH-3012 Bern, Switzerland.
| | - Jean-Marc Jeckelmann
- Institute of Biochemistry and Molecular Medicine, and Swiss National Centre of Competence in Research (NCCR) TransCure, University of Bern, CH-3012 Bern, Switzerland.
| | - Claire Colas
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
| | - Zöhre Ucurum
- Institute of Biochemistry and Molecular Medicine, and Swiss National Centre of Competence in Research (NCCR) TransCure, University of Bern, CH-3012 Bern, Switzerland.
| | - Avner Schlessinger
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
| | - Dimitrios Fotiadis
- Institute of Biochemistry and Molecular Medicine, and Swiss National Centre of Competence in Research (NCCR) TransCure, University of Bern, CH-3012 Bern, Switzerland.
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87
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Jungnickel KEJ, Parker JL, Newstead S. Structural basis for amino acid transport by the CAT family of SLC7 transporters. Nat Commun 2018; 9:550. [PMID: 29416041 PMCID: PMC5803215 DOI: 10.1038/s41467-018-03066-6] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 01/17/2018] [Indexed: 12/12/2022] Open
Abstract
Amino acids play essential roles in cell biology as regulators of metabolic pathways. Arginine in particular is a major signalling molecule inside the cell, being a precursor for both l-ornithine and nitric oxide (NO) synthesis and a key regulator of the mTORC1 pathway. In mammals, cellular arginine availability is determined by members of the solute carrier (SLC) 7 family of cationic amino acid transporters. Whereas CAT-1 functions to supply cationic amino acids for cellular metabolism, CAT-2A and -2B are required for macrophage activation and play important roles in regulating inflammation. Here, we present the crystal structure of a close homologue of the mammalian CAT transporters that reveals how these proteins specifically recognise arginine. Our structural and functional data provide a model for cationic amino acid transport in mammalian cells and reveals mechanistic insights into proton-coupled, sodium-independent amino acid transport in the wider APC superfamily. Cationic amino acid transporters (CATs) belong to the physiologically important solute carrier (SLC) 7 family. Here, the authors present the structure of the mammalian CAT transporter homologue Geobacillus kaustophilus GkApcT, which reveals how arginine is recognized, and propose a model for proton-coupled amino acid transport.
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Affiliation(s)
| | - Joanne L Parker
- 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.
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88
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Yoon BR, Oh YJ, Kang SW, Lee EB, Lee WW. Role of SLC7A5 in Metabolic Reprogramming of Human Monocyte/Macrophage Immune Responses. Front Immunol 2018; 9:53. [PMID: 29422900 PMCID: PMC5788887 DOI: 10.3389/fimmu.2018.00053] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 01/09/2018] [Indexed: 12/20/2022] Open
Abstract
Amino acids (AAs) are necessary nutrients which act not only as building blocks in protein synthesis but also in crucial anabolic cellular signaling pathways. It has been demonstrated that SLC7A5 is a critical transporter that mediates uptake of several essential amino acids in highly proliferative tumors and activated T cells. However, the dynamics and relevance of SLC7A5 activity in monocytes/macrophages is still poorly understood. We provide evidence that SLC7A5-mediated leucine influx contributes to pro-inflammatory cytokine production via mTOR complex 1 (mTORC1)-induced glycolytic reprograming in activated human monocytes/macrophages. Moreover, expression of SLC7A5 is significantly elevated in monocytes derived from patients with rheumatoid arthritis (RA), a chronic inflammatory disease, and was also markedly induced by LPS stimulation of both monocytes and macrophages from healthy individuals. Further, pharmacological blockade or silencing of SLC7A5 led to a significant reduction of IL-1β downstream of leucine-mediated mTORC1 activation. Inhibition of SLC7A5-mediated leucine influx was linked to downregulation of glycolytic metabolism as evidenced by the decreased extracellular acidification rate, suggesting a regulatory role for this molecule in glycolytic reprograming. Furthermore, the expression of SLC7A5 on circulating monocytes from RA patients positively correlated with clinical parameters, suggesting that SLC7A5-mediated AA influx is related to inflammatory conditions.
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Affiliation(s)
- Bo Ruem Yoon
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, South Korea
| | - Yoon-Jeong Oh
- Division of Rheumatology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, South Korea
| | - Seong Wook Kang
- Department of Internal Medicine, Chungnam National University School of Medicine, Daejeon, South Korea
| | - Eun Bong Lee
- Division of Rheumatology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, South Korea
| | - Won-Woo Lee
- Department of Microbiology and Immunology, Seoul National University College of Medicine, Seoul, South Korea.,Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, South Korea.,Cancer Research Institute, Seoul National University College of Medicine, Seoul, South Korea.,Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul, South Korea.,Institute of Infectious Diseases, Seoul National University College of Medicine, Seoul, South Korea.,Seoul National University Hospital Biomedical Research Institute, Seoul, South Korea
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89
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Schweizer U, Towell H, Vit A, Rodriguez-Ruiz A, Steegborn C. Structural aspects of thyroid hormone binding to proteins and competitive interactions with natural and synthetic compounds. Mol Cell Endocrinol 2017; 458:57-67. [PMID: 28131741 DOI: 10.1016/j.mce.2017.01.026] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Revised: 01/11/2017] [Accepted: 01/17/2017] [Indexed: 12/25/2022]
Abstract
Thyroid hormones and their metabolites constitute a vast class of related iodothyronine compounds that contribute to the regulation of metabolic activity and cell differentiation. They are in turn transported, transformed and recognized as signaling molecules through binding to a variety of proteins from a wide range of evolutionary unrelated protein families, which renders these proteins and their iodothyronine binding sites an example for extensive convergent evolution. In this review, we will briefly summarize what is known about iodothyronine binding sites in proteins, the modes of protein/iodothyronine interaction, and the ligand conformations. We will then discuss physiological and synthetic compounds, including popular drugs and food components, that can interfere with iodothyronine binding and recognition by these proteins. The discussion also includes compounds persisting in the environment and acting as endocrine disrupting chemicals.
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Affiliation(s)
- Ulrich Schweizer
- Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany.
| | - Holly Towell
- Lehrstuhl für Biochemie, Universität Bayreuth, Bayreuth, Germany
| | - Allegra Vit
- Lehrstuhl für Biochemie, Universität Bayreuth, Bayreuth, Germany
| | - Alfonso Rodriguez-Ruiz
- Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
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90
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Krause G, Hinz KM. Thyroid hormone transport across L-type amino acid transporters: What can molecular modelling tell us? Mol Cell Endocrinol 2017; 458:68-75. [PMID: 28341457 DOI: 10.1016/j.mce.2017.03.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 03/20/2017] [Accepted: 03/20/2017] [Indexed: 12/15/2022]
Abstract
Thyroid hormones (THs) and their derivatives require transmembrane transporters (TTs) to mediate their translocation across the cell membrane. Among these TTs, the L-type amino acid transporters (LAT) not only transport amino acids (AAs) but also certain THs and their derivatives. This review summarizes available knowledge concerning structure function patterns of the TH transport by LAT1 and LAT2. For example, LAT2 imports 3,3'-T2 and T3, but not rT3 and T4. In contrast to amino acids, THs are not at all exported by LAT2. Homology modelling of LAT1 and LAT2 is based on available crystal structures from the same superfamily the amino acid/polyamine/organocation transporter (APC). Molecular model guided mutagenesis has been used to predict substrate interaction sites. A common recognition feature for amino acid- and TH-derivatives has been suggested in an interior cavity of LAT1 and LAT2. Therein additional distinct molecular determinants that are responsible for the bidirectional AA transport but allowing only unidirectional import of particular THs have been confirmed for LAT2 by mutagenesis. Characterized substrate features that are needed for TH translocation and distinct LAT2 properties will be highlighted to understand the molecular import and export mechanisms of this transporter in more detail.
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Affiliation(s)
- Gerd Krause
- Leibniz-Institut für Molekulare Pharmakologie (FMP), Berlin, Germany.
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91
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Bolli E, O'Rourke JP, Conti L, Lanzardo S, Rolih V, Christen JM, Barutello G, Forni M, Pericle F, Cavallo F. A Virus-Like-Particle immunotherapy targeting Epitope-Specific anti-xCT expressed on cancer stem cell inhibits the progression of metastatic cancer in vivo. Oncoimmunology 2017; 7:e1408746. [PMID: 29399412 PMCID: PMC5790338 DOI: 10.1080/2162402x.2017.1408746] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 11/17/2017] [Accepted: 11/18/2017] [Indexed: 01/17/2023] Open
Abstract
Aggressive forms of breast cancer, such as Her2+ and triple negative breast cancer (TNBC), are enriched in breast cancer stem cells (BCSC) and have limited therapeutic options. BCSC represent a key cellular reservoir for relapse, metastatic progression and therapeutic resistance. Their ability to resist common cytotoxic therapies relies on different mechanisms, including improved detoxification. The cystine-glutamate antiporter protein xCT (SLC7A11) regulates cystine intake, conversion to cysteine and subsequent glutathione synthesis, protecting cells against oxidative and chemical insults. Our previous work showed that xCT is highly expressed in tumorspheres derived from breast cancer cell lines and downregulation of xCT altered BCSC function in vitro and inhibited pulmonary metastases in vivo. We further strengthened these observations by developing a virus-like-particle (VLP; AX09-0M6) immunotherapy targeting the xCT protein. AX09-0M6 elicited a strong antibody response against xCT including high levels of IgG2a antibody. IgG isolated from AX09-0M6 treated mice bound to tumorspheres, inhibited xCT function as assessed by reactive oxygen species generation and decreased BCSC growth and self-renewal. To assess if AX09-0M6 impacts BCSC in vivo seeding, Her2+ TUBO-derived tumorspheres were injected into the tail vein of AX09-0M6 or control treated female BALB/c mice. AX09-0M6 significantly inhibited formation of pulmonary nodules. To evaluate its ability to impact metastases, AX09-0M6 was administered to mice with established subcutaneous 4T1 tumors. AX09-0M6 administration significantly hampered tumor growth and development of pulmonary metastases. These data show that a VLP-based immunization approach inhibits xCT activity, impacts BCSC biology and significantly reduces metastatic progression in preclinical models.
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Affiliation(s)
- Elisabetta Bolli
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Torino, Torino, Italy
| | | | - Laura Conti
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Torino, Torino, Italy
| | - Stefania Lanzardo
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Torino, Torino, Italy
| | - Valeria Rolih
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Torino, Torino, Italy
| | | | - Giuseppina Barutello
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Torino, Torino, Italy
| | - Marco Forni
- EuroClone S.p.A Research Laboratory, Molecular Biotechnology Center, University of Torino, Torino, Italy
| | | | - Federica Cavallo
- Department of Molecular Biotechnology and Health Sciences, Molecular Biotechnology Center, University of Torino, Torino, Italy
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92
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Potent inhibitors of human LAT1 (SLC7A5) transporter based on dithiazole and dithiazine compounds for development of anticancer drugs. Biochem Pharmacol 2017; 143:39-52. [DOI: 10.1016/j.bcp.2017.07.006] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 07/07/2017] [Indexed: 12/11/2022]
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93
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Bhunia S, Vangala V, Bhattacharya D, Ravuri HG, Kuncha M, Chakravarty S, Sistla R, Chaudhuri A. Large Amino Acid Transporter 1 Selective Liposomes of l-DOPA Functionalized Amphiphile for Combating Glioblastoma. Mol Pharm 2017; 14:3834-3847. [PMID: 28958145 DOI: 10.1021/acs.molpharmaceut.7b00569] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Despite significant progress in neurosurgery and radiation therapy during the past decade, overall survivability (OS) of glioblastoma patients continues to be less than 2 years. The scope of systemic chemotherapy is greatly limited by poor drug transport across the blood brain barrier (BBB) and, thereby, suboptimal drug accumulation in glioma tissue. To this end, use of large amino acid transporter-1 (LAT1) overexpressed both on brain capillary endothelial cells (BCECs) and glioma cells has begun. Prior reports on the use of LAT1 mediated delivery of model drugs showed their brain accumulations. However, in depth in vivo glioblastoma regression studies aimed at examining the therapeutic potential of LAT1 mediated delivery of potent chemotherapeutics to brain tumor tissues have not yet been undertaken. Herein, we report on the development of a nanometric (100-135 nm) promising LAT1 selective liposomal drug carrier prepared from a novel l-3,4-dihydroxyphenylalanine (l-DOPA) functionalized amphiphile (Amphi-DOPA). In vitro studies using Rh-PE labeled liposomes of Amphi-DOPA both in untreated glioma (GL261) cells and in GL261cells preincubated with LAT1 antibody revealed LAT1 mediated cellular uptake. Intravenously administered NIR-dye labeled liposomes of Amphi-DOPA in glioblastoma-bearing mice showed preferential accumulation of the dye in brain tissue. Notably iv administration of WP1066-loaded liposomes of Amphi-DOPA enhanced the overall survivability of C57BL/6J mice bearing orthotopically established mouse glioblastoma by ∼60% compared to that for the untreated mouse group. Furthermore, we show that the OS of established glioblastoma-bearing mice can be significantly enhanced (by >300% compared to that for the untreated mouse group) when the presently described LAT1 mediated targeted chemotherapy with WP1066-loaded liposomes of Amphi-DOPA is combined with in vivo DC-targeted DNA vaccination using a survivin (a glioblastoma antigen) encoded DNA vaccine. The present findings open a new door for LAT1 mediated systemic chemotherapy of glioblastoma.
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Affiliation(s)
- Sukanya Bhunia
- Department of Chemical Biology, CSIR-Indian Institute of Chemical Technology , Uppal Road, Hyderabad 500007, India.,Academy of Scientific & Innovative Research (AcSIR) , 2 Rafi Marg, New Delhi, India
| | - Venugopal Vangala
- Department of Chemical Biology, CSIR-Indian Institute of Chemical Technology , Uppal Road, Hyderabad 500007, India.,Academy of Scientific & Innovative Research (AcSIR) , 2 Rafi Marg, New Delhi, India
| | - Dwaipayan Bhattacharya
- Department of Chemical Biology, CSIR-Indian Institute of Chemical Technology , Uppal Road, Hyderabad 500007, India.,Academy of Scientific & Innovative Research (AcSIR) , 2 Rafi Marg, New Delhi, India
| | - Halley Gora Ravuri
- School of Veterinary Science, University of Queensland , Gatton, Brisbane, Queensland Australia 4343
| | - Madhusudana Kuncha
- Medicinal Chemistry and Pharmacology Division, CSIR-Indian Institute of Chemical Technology , Uppal Road, Hyderabad 500007, India
| | - Sumana Chakravarty
- Department of Chemical Biology, CSIR-Indian Institute of Chemical Technology , Uppal Road, Hyderabad 500007, India.,Academy of Scientific & Innovative Research (AcSIR) , 2 Rafi Marg, New Delhi, India
| | - Ramakrishna Sistla
- Academy of Scientific & Innovative Research (AcSIR) , 2 Rafi Marg, New Delhi, India.,Medicinal Chemistry and Pharmacology Division, CSIR-Indian Institute of Chemical Technology , Uppal Road, Hyderabad 500007, India
| | - Arabinda Chaudhuri
- Department of Chemical Biology, CSIR-Indian Institute of Chemical Technology , Uppal Road, Hyderabad 500007, India.,Academy of Scientific & Innovative Research (AcSIR) , 2 Rafi Marg, New Delhi, India
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94
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Latek D. Rosetta Broker for membrane protein structure prediction: concentrative nucleoside transporter 3 and corticotropin-releasing factor receptor 1 test cases. BMC STRUCTURAL BIOLOGY 2017; 17:8. [PMID: 28774292 PMCID: PMC5543540 DOI: 10.1186/s12900-017-0078-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Accepted: 07/26/2017] [Indexed: 02/12/2023]
Abstract
Background Membrane proteins are difficult targets for structure prediction due to the limited structural data deposited in Protein Data Bank. Most computational methods for membrane protein structure prediction are based on the comparative modeling. There are only few de novo methods targeting that distinct protein family. In this work an example of such de novo method was used to structurally and functionally characterize two representatives of distinct membrane proteins families of solute carrier transporters and G protein-coupled receptors. The well-known Rosetta program and one of its protocols named Broker was used in two test cases. The first case was de novo structure prediction of three N-terminal transmembrane helices of the human concentrative nucleoside transporter 3 (hCNT3) homotrimer belonging to the solute carrier 28 family of transporters (SLC28). The second case concerned the large scale refinement of transmembrane helices of a homology model of the corticotropin-releasing factor receptor 1 (CRFR1) belonging to the G protein-coupled receptors family. Results The inward-facing model of the hCNT3 homotrimer was used to propose the functional impact of its single nucleotide polymorphisms. Additionally, the 100 ns molecular dynamics simulation of the unliganded hCNT3 model confirmed its validity and revealed mobility of the selected binding site and homotrimer interface residues. The large scale refinement of transmembrane helices of the CRFR1 homology model resulted in the significant improvement of its accuracy with respect to the crystal structure of CRFR1, especially in the binding site area. Consequently, the antagonist CP-376395 could be docked with Autodock VINA to the CRFR1 model without any steric clashes. Conclusions The presented work demonstrated that Rosetta Broker can be a versatile tool for solving various issues referring to protein biology. Two distinct examples of de novo membrane protein structure prediction presented here provided important insights into three major areas of protein biology. Namely, the dynamics of the inward-facing hCNT3 homotrimer system, the structural changes of the CRFR1 receptor upon the antagonist binding and finally, the role of single nucleotide polymorphisms in both, hCNT3 and CRFR1 proteins, were investigated. Electronic supplementary material The online version of this article (doi:10.1186/s12900-017-0078-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Dorota Latek
- Faculty of Chemistry, University of Warsaw, Pasteur St. 1, 02-093, Warsaw, Poland.
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95
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Khuri N, Zur AA, Wittwer MB, Lin L, Yee SW, Sali A, Giacomini KM. Computational Discovery and Experimental Validation of Inhibitors of the Human Intestinal Transporter OATP2B1. J Chem Inf Model 2017; 57:1402-1413. [PMID: 28562037 DOI: 10.1021/acs.jcim.6b00720] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Human organic anion transporters (OATPs) are vital for the uptake and efflux of drugs and endogenous compounds. Current identification of inhibitors of these transporters is based on experimental screening. Virtual screening remains a challenge due to a lack of experimental three-dimensional protein structures. Here, we describe a workflow to identify inhibitors of the OATP2B1 transporter in the DrugBank library of over 5,000 drugs and druglike molecules. OATP member 2B1 transporter is highly expressed in the intestine, where it participates in oral absorption of drugs. Predictions from a Random forest classifier, prioritized by docking against multiple comparative protein structure models of OATP2B1, indicated that 33 of the 5,000 compounds were putative inhibitors of OATP2B1. Ten predicted inhibitors that are prescription drugs were tested experimentally in cells overexpressing the OATP2B1 transporter. Three of these ten were validated as potent inhibitors of estrone-3-sulfate uptake (defined as more than 50% inhibition at 20 μM) and tested in multiple concentrations to determine exact IC50. The IC50 values of bicalutamide, ticagrelor, and meloxicam suggest that they might inhibit intestinal OATP2B1 at clinically relevant concentrations and therefore modulate the absorption of other concomitantly administered drugs.
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Affiliation(s)
- Natalia Khuri
- Bioengineering Department, Stanford University , Stanford, California 94305, United States
| | | | | | | | | | - Andrej Sali
- Department of Pharmaceutical Chemistry and California Institute of Quantitative Biosciences (QB3), University of California San Francisco , San Francisco, California 94158, United States
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96
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Impaired Amino Acid Transport at the Blood Brain Barrier Is a Cause of Autism Spectrum Disorder. Cell 2017; 167:1481-1494.e18. [PMID: 27912058 DOI: 10.1016/j.cell.2016.11.013] [Citation(s) in RCA: 215] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 10/18/2016] [Accepted: 11/03/2016] [Indexed: 12/29/2022]
Abstract
Autism spectrum disorders (ASD) are a group of genetic disorders often overlapping with other neurological conditions. We previously described abnormalities in the branched-chain amino acid (BCAA) catabolic pathway as a cause of ASD. Here, we show that the solute carrier transporter 7a5 (SLC7A5), a large neutral amino acid transporter localized at the blood brain barrier (BBB), has an essential role in maintaining normal levels of brain BCAAs. In mice, deletion of Slc7a5 from the endothelial cells of the BBB leads to atypical brain amino acid profile, abnormal mRNA translation, and severe neurological abnormalities. Furthermore, we identified several patients with autistic traits and motor delay carrying deleterious homozygous mutations in the SLC7A5 gene. Finally, we demonstrate that BCAA intracerebroventricular administration ameliorates abnormal behaviors in adult mutant mice. Our data elucidate a neurological syndrome defined by SLC7A5 mutations and support an essential role for the BCAA in human brain function.
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97
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Novel insights into the transport mechanism of the human amino acid transporter LAT1 (SLC7A5). Probing critical residues for substrate translocation. Biochim Biophys Acta Gen Subj 2017; 1861:727-736. [DOI: 10.1016/j.bbagen.2017.01.013] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 12/21/2016] [Accepted: 01/10/2017] [Indexed: 12/31/2022]
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98
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Modulation of LAT1 (SLC7A5) transporter activity and stability by membrane cholesterol. Sci Rep 2017; 7:43580. [PMID: 28272458 PMCID: PMC5341093 DOI: 10.1038/srep43580] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 01/25/2017] [Indexed: 11/17/2022] Open
Abstract
LAT1 (SLC7A5) is a transporter for both the uptake of large neutral amino acids and a number of pharmaceutical drugs. It is expressed in numerous cell types including T-cells, cancer cells and brain endothelial cells. However, mechanistic knowledge of how it functions and its interactions with lipids are unknown or limited due to inability of obtaining stable purified protein in sufficient quantities. Our data show that depleting cellular cholesterol reduced the Vmax but not the Km of the LAT1 mediated uptake of a model substrate into cells (L-DOPA). A soluble cholesterol analogue was required for the stable purification of the LAT1 with its chaperon CD98 (4F2hc,SLC3A2) and that this stabilised complex retained the ability to interact with a substrate. We propose cholesterol interacts with the conserved regions in the LAT1 transporter that have been shown to bind to cholesterol/CHS in Drosophila melanogaster dopamine transporter. In conclusion, LAT1 is modulated by cholesterol impacting on its stability and transporter activity. This novel finding has implications for other SLC7 family members and additional eukaryotic transporters that contain the LeuT fold.
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99
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Parks SK, Cormerais Y, Pouysségur J. Hypoxia and cellular metabolism in tumour pathophysiology. J Physiol 2017; 595:2439-2450. [PMID: 28074546 DOI: 10.1113/jp273309] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 12/01/2016] [Indexed: 12/17/2022] Open
Abstract
Cancer cells are optimised for growth and survival via an ability to outcompete normal cells in their microenvironment. Many of these advantageous cellular adaptations are promoted by the pathophysiological hypoxia that arises in solid tumours due to incomplete vascularisation. Tumour cells are thus faced with the challenge of an increased need for nutrients to support the drive for proliferation in the face of a diminished extracellular supply. Among the many modifications occurring in tumour cells, hypoxia inducible factors (HIFs) act as essential drivers of key pro-survival pathways via the promotion of numerous membrane and cytosolic proteins. Here we focus our attention on two areas: the role of amino acid uptake and the handling of metabolic acid (CO2 /H+ ) production. We provide evidence for a number of hypoxia-induced proteins that promote cellular anabolism and regulation of metabolic acid-base levels in tumour cells including amino-acid transporters (LAT1), monocarboxylate transporters, and acid-base regulating carbonic anhydrases (CAs) and bicarbonate transporters (NBCs). Emphasis is placed on current work manipulating multiple CA isoforms and NBCs, which is at an interesting crossroads of gas physiology as they are regulated by hypoxia to contribute to the cellular handling of CO2 and pHi regulation. Our research combined with others indicates that targeting of HIF-regulated membrane proteins in tumour cells will provide promising future anti-cancer therapeutic approaches and we suggest strategies that could be potentially used to enhance these tactics.
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Affiliation(s)
- Scott K Parks
- Medical Biology Department, Centre Scientifique de Monaco, 8 Quai Antoine 1er, MC-98000, Monaco, Principality of Monaco
| | - Yann Cormerais
- Medical Biology Department, Centre Scientifique de Monaco, 8 Quai Antoine 1er, MC-98000, Monaco, Principality of Monaco
| | - Jacques Pouysségur
- Medical Biology Department, Centre Scientifique de Monaco, 8 Quai Antoine 1er, MC-98000, Monaco, Principality of Monaco.,Institute for Research on Cancer and Aging (IRCAN), CNRS, INSERM, Centre A. Lacassagne, University of Nice-Sophia Antipolis, Nice, France
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Cheng Q, Shah N, Bröer A, Fairweather S, Jiang Y, Schmoll D, Corry B, Bröer S. Identification of novel inhibitors of the amino acid transporter B 0 AT1 (SLC6A19), a potential target to induce protein restriction and to treat type 2 diabetes. Br J Pharmacol 2017; 174:468-482. [PMID: 28176326 DOI: 10.1111/bph.13711] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 12/28/2016] [Accepted: 01/04/2017] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND AND PURPOSE The neutral amino acid transporter B0 AT1 (SLC6A19) has recently been identified as a possible target to treat type 2 diabetes and related disorders. B0 AT1 mediates the Na+ -dependent uptake of all neutral amino acids. For surface expression and catalytic activity, B0 AT1 requires coexpression of collectrin (TMEM27). In this study, we established tools to identify and evaluate novel inhibitors of B0 AT1. EXPERIMENTAL APPROACH A CHO-based cell line was generated, stably expressing collectrin and B0 AT1. Using this cell line, a high-throughput screening assay was developed, which uses a fluorescent dye to detect depolarisation of the cell membrane during amino acid uptake via B0 AT1. In parallel to these functional assays, we ran a computational compound screen using AutoDock4 and a homology model of B0 AT1 based on the high-resolution structure of the highly homologous Drosophila dopamine transporter. KEY RESULTS We characterized a series of novel inhibitors of the B0 AT1 transporter. Benztropine was identified as a competitive inhibitor of the transporter showing an IC50 of 44 ± 9 μM. The compound was selective with regard to related transporters and blocked neutral amino acid uptake in inverted sections of mouse intestine. CONCLUSION AND IMPLICATIONS The tools established in this study can be widely used to identify new transport inhibitors. Using these tools, we were able to identify compounds that can be used to study epithelial transport, to induce protein restriction, or be developed further through medicinal chemistry.
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Affiliation(s)
- Qi Cheng
- Research School of Biology, The Australian National University, Canberra, Australia
| | - Nishank Shah
- Research School of Biology, The Australian National University, Canberra, Australia
| | - Angelika Bröer
- Research School of Biology, The Australian National University, Canberra, Australia
| | - Stephen Fairweather
- Research School of Biology, The Australian National University, Canberra, Australia
| | - Yang Jiang
- Research School of Biology, The Australian National University, Canberra, Australia
| | - Dieter Schmoll
- Industriepark Hoechst, Sanofi-Aventis Deutschland GmbH, Frankfurt am Main, Germany
| | - Ben Corry
- Research School of Biology, The Australian National University, Canberra, Australia
| | - Stefan Bröer
- Research School of Biology, The Australian National University, Canberra, Australia
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