1
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Chen M, Wang G, Xu Z, Sun J, Liu B, Chang L, Gu J, Ruan Y, Gao X, Song S. Loss of RACK1 promotes glutamine addiction via activating AKT/mTOR/ASCT2 axis to facilitate tumor growth in gastric cancer. Cell Oncol (Dordr) 2024; 47:113-128. [PMID: 37578594 DOI: 10.1007/s13402-023-00854-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/31/2023] [Indexed: 08/15/2023] Open
Abstract
BACKGROUND Metabolic reprogramming is closely related to the development of gastric cancer (GC), which remains as the fourth leading cause of cancer-related death worldwide. As a tumor suppressor for GC, whether receptor for activated C-kinase 1 (RACK1) play a modulatory role in metabolic reprogramming remains largely unclear. METHODS GC cell lines and cell-derived xenograft mouse model were used to identify the biological function of RACK1. Flow cytometry and Seahorse assays were applied to examine cell cycle and oxygen consumption rate (OCR), respectively. Western blot, real-time PCR and autophagy double fluorescent assays were utilized to explore the signaling. Immunohistochemistry was performed to detect the expression of RACK1 and other indicators in tissue sections. RESULTS Loss of RACK1 facilitated the viability, colony formation, cell cycle progression and OCR of GC cells in a glutamine-dependent manner. Further investigation revealed that RACK1 knockdown inhibited the lysosomal degradation of Alanine-serine-cysteine amino acid transporter 2 (ASCT2). Mechanistically, depletion of RACK1 remarkably decreased PTEN expression through up-regulating miR-146b-5p, leading to the activation of AKT/mTOR signaling pathway which dampened autophagy flux subsequently. Moreover, knockdown of ASCT2 could reverse the promotive effect of RACK1 depletion on GC tumor growth both in vitro and in vivo. Tissue microarray confirmed that RACK1 was negatively correlated with the expression of ASCT2 and p62, as well as the phosphorylation of mTOR. CONCLUSION Together, our results demonstrate that the suppressive function of RACK1 in GC is associated with ASCT2-mediated glutamine metabolism, and imply that targeting RACK1/ASCT2 axis provides potential strategies for GC treatment.
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Affiliation(s)
- Mengqian Chen
- Department of Biochemistry and Molecular Biology & NHC Key Laboratory of Glycoconjugates Research, School of Basic Medical Sciences, Fudan University, 138 Yixueyuan Road, Shanghai, 200032, People's Republic of China
| | - Gaojia Wang
- Department of Biochemistry and Molecular Biology & NHC Key Laboratory of Glycoconjugates Research, School of Basic Medical Sciences, Fudan University, 138 Yixueyuan Road, Shanghai, 200032, People's Republic of China
| | - Zhijian Xu
- Department of Biochemistry and Molecular Biology & NHC Key Laboratory of Glycoconjugates Research, School of Basic Medical Sciences, Fudan University, 138 Yixueyuan Road, Shanghai, 200032, People's Republic of China
| | - Jie Sun
- Department of General Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032, People's Republic of China
| | - Bo Liu
- Department of Biochemistry and Molecular Biology & NHC Key Laboratory of Glycoconjugates Research, School of Basic Medical Sciences, Fudan University, 138 Yixueyuan Road, Shanghai, 200032, People's Republic of China
| | - Lei Chang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, People's Republic of China
| | - Jianxin Gu
- Department of Biochemistry and Molecular Biology & NHC Key Laboratory of Glycoconjugates Research, School of Basic Medical Sciences, Fudan University, 138 Yixueyuan Road, Shanghai, 200032, People's Republic of China
| | - Yuanyuan Ruan
- Department of Biochemistry and Molecular Biology & NHC Key Laboratory of Glycoconjugates Research, School of Basic Medical Sciences, Fudan University, 138 Yixueyuan Road, Shanghai, 200032, People's Republic of China
| | - Xiaodong Gao
- Department of General Surgery, Zhongshan Hospital, Fudan University, 180 Fenglin Road, Shanghai, 200032, People's Republic of China.
| | - Shushu Song
- Department of Biochemistry and Molecular Biology & NHC Key Laboratory of Glycoconjugates Research, School of Basic Medical Sciences, Fudan University, 138 Yixueyuan Road, Shanghai, 200032, People's Republic of China.
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Alam S, Doherty E, Ortega-Prieto P, Arizanova J, Fets L. Membrane transporters in cell physiology, cancer metabolism and drug response. Dis Model Mech 2023; 16:dmm050404. [PMID: 38037877 PMCID: PMC10695176 DOI: 10.1242/dmm.050404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2023] Open
Abstract
By controlling the passage of small molecules across lipid bilayers, membrane transporters influence not only the uptake and efflux of nutrients, but also the metabolic state of the cell. With more than 450 members, the Solute Carriers (SLCs) are the largest transporter super-family, clustering into families with different substrate specificities and regulatory properties. Cells of different types are, therefore, able to tailor their transporter expression signatures depending on their metabolic requirements, and the physiological importance of these proteins is illustrated by their mis-regulation in a number of disease states. In cancer, transporter expression is heterogeneous, and the SLC family has been shown to facilitate the accumulation of biomass, influence redox homeostasis, and also mediate metabolic crosstalk with other cell types within the tumour microenvironment. This Review explores the roles of membrane transporters in physiological and malignant settings, and how these roles can affect drug response, through either indirect modulation of sensitivity or the direct transport of small-molecule therapeutic compounds into cells.
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Affiliation(s)
- Sara Alam
- Drug Transport and Tumour Metabolism Lab, MRC Laboratory of Medical Sciences, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK
| | - Emily Doherty
- Drug Transport and Tumour Metabolism Lab, MRC Laboratory of Medical Sciences, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK
| | - Paula Ortega-Prieto
- Drug Transport and Tumour Metabolism Lab, MRC Laboratory of Medical Sciences, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK
| | - Julia Arizanova
- Drug Transport and Tumour Metabolism Lab, MRC Laboratory of Medical Sciences, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK
| | - Louise Fets
- Drug Transport and Tumour Metabolism Lab, MRC Laboratory of Medical Sciences, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK
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3
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Du D, Qin M, Shi L, Liu C, Jiang J, Liao Z, Wang H, Zhang Z, Sun L, Fan H, Liu Z, Yu H, Li H, Peng J, Yuan S, Yang M, Xiong J. RNA binding motif protein 45-mediated phosphorylation enhances protein stability of ASCT2 to promote hepatocellular carcinoma progression. Oncogene 2023; 42:3127-3141. [PMID: 37658192 DOI: 10.1038/s41388-023-02795-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 07/17/2023] [Accepted: 07/24/2023] [Indexed: 09/03/2023]
Abstract
Targeting metabolic remodeling represents a potentially promising strategy for hepatocellular carcinoma (HCC) therapy. In-depth understanding on the regulation of the glutamine transporter alanine-serine-cysteine transporter 2 (ASCT2) contributes to the development of novel promising therapeutics. As a developmentally regulated RNA binding protein, RBM45 is capable to shuttle between nucleus and cytoplasm, and directly interacts with proteins. By bioinformatics analysis, we screened out that RBM45 was elevated in the HCC patient specimens and positively correlated with poor prognosis. RBM45 promoted cell proliferation, boosted xenograft tumorigenicity and accelerated HCC progression. Using untargeted metabolomics, it was found that RBM45 interfered with glutamine metabolism. Further results demonstrated that RBM45 positively associated with ASCT2 in human and mouse specimens. Moreover, RBM45 enhanced ASCT2 protein stability by counteracting autophagy-independent lysosomal degradation. Significantly, wild-type ASCT2, instead of phospho-defective mutants, rescued siRBM45-suppressed HCC cell proliferation. Using molecular docking approaches, we found AG-221, a mutant isocitrate dehydrogenase 2 (mIDH2) inhibitor for acute myeloid leukemia therapy, pharmacologically perturbed RBM45-ASCT2 interaction, decreased ASCT2 stability and suppressed HCC progression. These findings provide evidence that RBM45 plays a crucial role in HCC progression via interacting with and counteracting the degradation of ASCT2. Our findings suggest a novel alternative structural sites for the design of ASCT2 inhibitors and the agents interfering with RBM45-ASCT2 interaction may be a potential direction for HCC drug development.
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Affiliation(s)
- Danyu Du
- Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China
- Institute of Pharmaceutical Sciences, China Pharmaceutical University, Nanjing, 210009, China
| | - Mengyao Qin
- Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China
- Institute of Pharmaceutical Sciences, China Pharmaceutical University, Nanjing, 210009, China
| | - Li Shi
- Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China
| | - Chan Liu
- Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China
- Institute of Pharmaceutical Sciences, China Pharmaceutical University, Nanjing, 210009, China
| | - Jingwei Jiang
- Shuangyun BioMed Sci & Tech Co., Ltd., Suzhou, 215000, China
| | - Zhengguang Liao
- Institute of Pharmaceutical Sciences, China Pharmaceutical University, Nanjing, 210009, China
| | - Hongxv Wang
- Institute of Pharmaceutical Sciences, China Pharmaceutical University, Nanjing, 210009, China
| | - Zhibo Zhang
- Institute of Pharmaceutical Sciences, China Pharmaceutical University, Nanjing, 210009, China
| | - Li Sun
- Institute of Pharmaceutical Sciences, China Pharmaceutical University, Nanjing, 210009, China
| | - Hui Fan
- Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China
| | - Zhengrui Liu
- Institute of Pharmaceutical Sciences, China Pharmaceutical University, Nanjing, 210009, China
| | - Hong Yu
- Department of Pathology, Taizhou People's Hospital Affiliated to Dalian Medical University, Taizhou, 225300, Jiangsu, China
| | - Hongyang Li
- Institute of Dermatology, Chinese Academy of Medical Science & Peking Union Medical College, Nanjing, 210042, China
| | - Jun Peng
- Institute of Pharmaceutical Sciences, China Pharmaceutical University, Nanjing, 210009, China
| | - Shengtao Yuan
- Institute of Pharmaceutical Sciences, China Pharmaceutical University, Nanjing, 210009, China.
| | - Mei Yang
- Institute of Pharmaceutical Sciences, China Pharmaceutical University, Nanjing, 210009, China.
| | - Jing Xiong
- Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China.
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Abstract
The uptake and metabolism of nutrients support fundamental cellular process from bioenergetics to biomass production and cell fate regulation. While many studies of cell metabolism focus on cancer cells, the principles of metabolism elucidated in cancer cells apply to a wide range of mammalian cells. The goal of this review is to discuss how the field of cancer metabolism provides a framework for revealing principles of cell metabolism and for dissecting the metabolic networks that allow cells to meet their specific demands. Understanding context-specific metabolic preferences and liabilities will unlock new approaches to target cancer cells to improve patient care.
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Affiliation(s)
- Lydia W S Finley
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
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5
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Wang D, Wan X. Progress in research on the role of amino acid metabolic reprogramming in tumour therapy: A review. Biomed Pharmacother 2022; 156:113923. [DOI: 10.1016/j.biopha.2022.113923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 10/16/2022] [Accepted: 10/24/2022] [Indexed: 11/26/2022] Open
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6
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Pavlova NN, Zhu J, Thompson CB. The hallmarks of cancer metabolism: Still emerging. Cell Metab 2022; 34:355-377. [PMID: 35123658 PMCID: PMC8891094 DOI: 10.1016/j.cmet.2022.01.007] [Citation(s) in RCA: 409] [Impact Index Per Article: 204.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 01/13/2022] [Accepted: 01/19/2022] [Indexed: 12/14/2022]
Abstract
Metabolism of cancer cells is geared toward biomass production and proliferation. Since the metabolic resources within the local tissue are finite, this can lead to nutrient depletion and accumulation of metabolic waste. To maintain growth in these conditions, cancer cells employ a variety of metabolic adaptations, the nature of which is collectively determined by the physiology of their cell of origin, the identity of transforming lesions, and the tissue in which cancer cells reside. Furthermore, select metabolites not only serve as substrates for energy and biomass generation, but can also regulate gene and protein expression and influence the behavior of non-transformed cells in the tumor vicinity. As they grow and metastasize, tumors can also affect and be affected by the nutrient distribution within the body. In this hallmark update, recent advances are incorporated into a conceptual framework that may help guide further research efforts in exploring cancer cell metabolism.
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Affiliation(s)
- Natalya N Pavlova
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Jiajun Zhu
- Department of Basic Medical Sciences, School of Medicine, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Center for Life Sciences, Beijing 100084, China
| | - Craig B Thompson
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
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7
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Lopes C, Pereira C, Medeiros R. ASCT2 and LAT1 Contribution to the Hallmarks of Cancer: From a Molecular Perspective to Clinical Translation. Cancers (Basel) 2021; 13:cancers13020203. [PMID: 33429909 PMCID: PMC7828050 DOI: 10.3390/cancers13020203] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 12/31/2020] [Accepted: 01/07/2021] [Indexed: 02/06/2023] Open
Abstract
The role of the amino acid transporters ASCT2 and LAT1 in cancer has been explored throughout the years. In this review, we report their impact on the hallmarks of cancer, as well as their clinical significance. Overall, both proteins have been associated with cell death resistance through dysregulation of caspases and sustainment of proliferative signaling through mTOR activation. Furthermore, ASCT2 appears to play an important role in cellular energetics regulation, whereas LAT1 expression is associated with angiogenesis and invasion and metastasis activation. The molecular impact of these proteins on the hallmarks of cancer translates into various clinical applications and both transporters have been identified as prognostic factors in many types of cancer. Concerning their role as therapeutic targets, efforts have been undertaken to synthesize competitive or irreversible ASCT2 and LAT1 inhibitors. However, JHP203, a selective inhibitor of the latter, is, to the best of our knowledge, the only compound included in a Phase 1 clinical trial. In conclusion, considering the usefulness of ASCT2 and LAT1 in a variety of cancer-related pathways and cancer therapy/diagnosis, the development and testing of novel inhibitors for these transporters that could be evaluated in clinical trials represents a promising approach to cancer prognosis improvement.
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Affiliation(s)
- Catarina Lopes
- Molecular Oncology and Viral Pathology Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO-Porto), Rua Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal; (C.L.); (R.M.)
| | - Carina Pereira
- Molecular Oncology and Viral Pathology Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO-Porto), Rua Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal; (C.L.); (R.M.)
- CINTESIS—Center for Health Technology and Services Research, University of Porto, Rua Dr. Plácido da Costa, 4200-450 Porto, Portugal
- Correspondence: ; Tel.: +351-225-084-000; Fax: +351-225-084-001
| | - Rui Medeiros
- Molecular Oncology and Viral Pathology Group, IPO Porto Research Center (CI-IPOP), Portuguese Oncology Institute of Porto (IPO-Porto), Rua Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal; (C.L.); (R.M.)
- Research Department of the Portuguese League Against Cancer—North (LPCC-NRNorte), Estrada da Circunvalação, 4200-177 Porto, Portugal
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8
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Target the human Alanine/Serine/Cysteine Transporter 2(ASCT2): Achievement and Future for Novel Cancer Therapy. Pharmacol Res 2020; 158:104844. [DOI: 10.1016/j.phrs.2020.104844] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 04/12/2020] [Accepted: 04/13/2020] [Indexed: 12/11/2022]
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9
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Schömel N, Hancock SE, Gruber L, Olzomer EM, Byrne FL, Shah D, Hoehn KL, Turner N, Grösch S, Geisslinger G, Wegner MS. UGCG influences glutamine metabolism of breast cancer cells. Sci Rep 2019; 9:15665. [PMID: 31666638 PMCID: PMC6821892 DOI: 10.1038/s41598-019-52169-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 10/14/2019] [Indexed: 01/07/2023] Open
Abstract
UDP-glucose ceramide glucosyltransferase (UGCG) is the key enzyme in glycosphingolipid (GSL) metabolism by being the only enzyme that generates glucosylceramide (GlcCer) de novo. Increased UGCG synthesis is associated with pro-cancerous processes such as increased proliferation and multidrug resistance in several cancer types. We investigated the influence of UGCG overexpression on glutamine metabolism in breast cancer cells. We observed adapted glucose and glutamine uptake in a limited energy supply environment following UGCG overexpression. Glutamine is used for reinforced oxidative stress response shown by increased mRNA expression of glutamine metabolizing proteins such as glutathione-disulfide reductase (GSR) resulting in increased reduced glutathione (GSH) level. Augmented glutamine uptake is also used for fueling the tricarboxylic acid (TCA) cycle to maintain the proliferative advantage of UGCG overexpressing cells. Our data reveal a link between GSL and glutamine metabolism in breast cancer cells, which is to our knowledge a novel correlation in the field of sphingolipid research.
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Affiliation(s)
- Nina Schömel
- pharmazentrum frankfurt/ZAFES, Institute of Clinical Pharmacology, Johann Wolfgang Goethe University, Theodor Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Sarah E Hancock
- School of Medical Sciences, University of New South Wales, Sydney, New South Wales, 2052, Australia
| | - Lisa Gruber
- pharmazentrum frankfurt/ZAFES, Institute of Clinical Pharmacology, Johann Wolfgang Goethe University, Theodor Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Ellen M Olzomer
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, 2052, Australia
| | - Frances L Byrne
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, 2052, Australia
| | - Divya Shah
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, 2052, Australia
| | - Kyle L Hoehn
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, 2052, Australia
| | - Nigel Turner
- School of Medical Sciences, University of New South Wales, Sydney, New South Wales, 2052, Australia
| | - Sabine Grösch
- pharmazentrum frankfurt/ZAFES, Institute of Clinical Pharmacology, Johann Wolfgang Goethe University, Theodor Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Gerd Geisslinger
- pharmazentrum frankfurt/ZAFES, Institute of Clinical Pharmacology, Johann Wolfgang Goethe University, Theodor Stern-Kai 7, 60590, Frankfurt am Main, Germany.,Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Project Group Translational Medicine and Pharmacology (TMP), Theodor Stern-Kai 7, 60590, Frankfurt am Main, Germany
| | - Marthe-Susanna Wegner
- pharmazentrum frankfurt/ZAFES, Institute of Clinical Pharmacology, Johann Wolfgang Goethe University, Theodor Stern-Kai 7, 60590, Frankfurt am Main, Germany.
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10
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Scalise M, Pochini L, Console L, Losso MA, Indiveri C. The Human SLC1A5 (ASCT2) Amino Acid Transporter: From Function to Structure and Role in Cell Biology. Front Cell Dev Biol 2018; 6:96. [PMID: 30234109 PMCID: PMC6131531 DOI: 10.3389/fcell.2018.00096] [Citation(s) in RCA: 150] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 08/08/2018] [Indexed: 12/30/2022] Open
Abstract
SLC1A5, known as ASCT2, is a neutral amino acid transporter belonging to the SLC1 family and localized in the plasma membrane of several body districts. ASCT2 is an acronym standing for Alanine, Serine, Cysteine Transporter 2 even if the preferred substrate is the conditionally essential amino acid glutamine, with cysteine being a modulator and not a substrate. The studies around amino acid transport in cells and tissues began in the '60s by using radiolabeled compounds and competition assays. After identification of murine and human genes, the function of the coded protein has been studied in cell system and in proteoliposomes revealing that this transporter is a Na+ dependent antiporter of neutral amino acids, some of which are only inwardly transported and others are bi-directionally exchanged. The functional asymmetry merged with the kinetic asymmetry in line with the physiological role of amino acid pool harmonization. An intriguing function has been described for ASCT2 that is exploited as a receptor by a group of retroviruses to infect human cells. Interactions with scaffold proteins and post-translational modifications regulate ASCT2 stability, trafficking and transport activity. Two asparagine residues, namely N163 and N212, are the sites of glycosylation that is responsible for the definitive localization into the plasma membrane. ASCT2 expression increases in highly proliferative cells such as inflammatory and stem cells to fulfill the augmented glutamine demand. Interestingly, for the same reason, the expression of ASCT2 is greatly enhanced in many human cancers. This finding has generated interest in its candidacy as a pharmacological target for new anticancer drugs. The recently solved 3D structure of ASCT2 will aid in the rational design of such therapeutic compounds.
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Affiliation(s)
- Mariafrancesca Scalise
- Department DiBEST (Biologia, Ecologia, Scienze Della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Cosenza, Italy
| | - Lorena Pochini
- Department DiBEST (Biologia, Ecologia, Scienze Della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Cosenza, Italy
| | - Lara Console
- Department DiBEST (Biologia, Ecologia, Scienze Della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Cosenza, Italy
| | - Maria A Losso
- Department DiBEST (Biologia, Ecologia, Scienze Della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Cosenza, Italy
| | - Cesare Indiveri
- Department DiBEST (Biologia, Ecologia, Scienze Della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Cosenza, Italy.,CNR Institute of Biomembranes, Bioenergetics and Molecular Biotechnology, Bari, Italy
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11
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Yang Z, Follett J, Kerr MC, Clairfeuille T, Chandra M, Collins BM, Teasdale RD. Sorting nexin 27 (SNX27) regulates the trafficking and activity of the glutamine transporter ASCT2. J Biol Chem 2018; 293:6802-6811. [PMID: 29563155 DOI: 10.1074/jbc.ra117.000735] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 02/27/2018] [Indexed: 12/14/2022] Open
Abstract
Alanine-, serine-, cysteine-preferring transporter 2 (ASCT2, SLC1A5) is responsible for the uptake of glutamine into cells, a major source of cellular energy and a key regulator of mammalian target of rapamycin (mTOR) activation. Furthermore, ASCT2 expression has been reported in several human cancers, making it a potential target for both diagnostic and therapeutic purposes. Here we identify ASCT2 as a membrane-trafficked cargo molecule, sorted through a direct interaction with the PDZ domain of sorting nexin 27 (SNX27). Using both membrane fractionation and subcellular localization approaches, we demonstrate that the majority of ASCT2 resides at the plasma membrane. This is significantly reduced within CrispR-mediated SNX27 knockout (KO) cell lines, as it is missorted into the lysosomal degradation pathway. The reduction of ASCT2 levels in SNX27 KO cells leads to decreased glutamine uptake, which, in turn, inhibits cellular proliferation. SNX27 KO cells also present impaired activation of the mTOR complex 1 (mTORC1) pathway and enhanced autophagy. Taken together, our data reveal a role for SNX27 in glutamine uptake and amino acid-stimulated mTORC1 activation via modulation of ASCT2 intracellular trafficking.
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Affiliation(s)
- Zhe Yang
- From the School of Biomedical Sciences, Faculty of Medicine, and.,Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Jordan Follett
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Markus C Kerr
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Thomas Clairfeuille
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Mintu Chandra
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Brett M Collins
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Rohan D Teasdale
- From the School of Biomedical Sciences, Faculty of Medicine, and .,Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
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12
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Hu J, Shi Y, Wang C, Wan H, Wu D, Wang H, Peng X. Role of intestinal trefoil factor in protecting intestinal epithelial cells from burn-induced injury. Sci Rep 2018; 8:3201. [PMID: 29453360 PMCID: PMC5816625 DOI: 10.1038/s41598-018-21282-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 01/30/2018] [Indexed: 12/19/2022] Open
Abstract
Although intestinal trefoil factor (ITF) can alleviate the burn-induced intestinal mucosa injury, the underlying mechanisms remains elusive. In this study, we investigated if ITF alters glutamine transport on the brush border membrane vesicles (BBMVs) of the intestines in Sprague-Dawley rats inflicted with 30% TBSA and the underlying mechanisms. We found that ITF significantly stimulated intestinal glutamine transport in burned rats. Mechanistically, ITF enhanced autophagy, reduces endoplasmic reticulum stress (ERS), and alleviates the impaired PDI, ASCT2, and B0AT1 in IECs and BBMVs after burn injury likely through AMPK activation. Therefore, ITF may protect intestinal epithelial cells from burn-induced injury through improving glutamine transport by alleviating ERS.
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Affiliation(s)
- Jianhong Hu
- Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, The Third Military Medical University, Chongqing, 400038, China
| | - Yan Shi
- Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, The Third Military Medical University, Chongqing, 400038, China
| | - Chao Wang
- Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, The Third Military Medical University, Chongqing, 400038, China
| | - Hanxing Wan
- Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, The Third Military Medical University, Chongqing, 400038, China
| | - Dan Wu
- Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, The Third Military Medical University, Chongqing, 400038, China
| | - Hongyu Wang
- Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, The Third Military Medical University, Chongqing, 400038, China
| | - Xi Peng
- Institute of Burn Research, State Key Laboratory of Trauma, Burns and Combined Injury, Southwest Hospital, The Third Military Medical University, Chongqing, 400038, China.
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13
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Ye J, Zhang R, Wu F, Zhai L, Wang K, Xiao M, Xie T, Sui X. Non-apoptotic cell death in malignant tumor cells and natural compounds. Cancer Lett 2018; 420:210-227. [PMID: 29410006 DOI: 10.1016/j.canlet.2018.01.061] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 01/18/2018] [Accepted: 01/24/2018] [Indexed: 12/18/2022]
Abstract
Traditional cancer therapy is mainly targeting on enhancing cell apoptosis, however, it is well established that many cancer cells are chemo-resistant and defective in apoptosis induction. Therefore, it may have important therapeutic implications to exploit some novel natural compounds based on non-apoptotic programmed cell death. Currently, accumulating evidence shows that the compounds from nature source can induce non-apoptotic programmed cell death in cancer cells, and therefore these natural compounds have gained a great promise for the future anticancer therapeutics. In this review, we will concentrate our efforts on the latest developments regarding major forms of non-apoptotic programmed cell death--autophagic cell death, necroptosis, ferroptosis, pyroptosis, glutamoptosis and exosome-associated cell death. Our increased understanding of the role of natural compounds in regulating non-apoptotic programmed cell death will hopefully provide prospective strategies for cancer therapy.
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Affiliation(s)
- Jing Ye
- Department of Otolaryngology Head and Neck Surgery, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ruonan Zhang
- Department of Medical Oncology, Holistic Integrative Oncology Institutes and Holistic Integrative Cancer Center of Traditional Chinese and Western Medicine, The Affiliated Hospital of Hangzhou Normal University, College of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China; Department of Cancer Pharmacology, Holistic Integrative Pharmacy Institutes, College of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China
| | - Fan Wu
- Des Moines Medical School, Des Moines, IA, USA
| | - Lijuan Zhai
- Department of Medical Oncology, Holistic Integrative Oncology Institutes and Holistic Integrative Cancer Center of Traditional Chinese and Western Medicine, The Affiliated Hospital of Hangzhou Normal University, College of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China; Department of Cancer Pharmacology, Holistic Integrative Pharmacy Institutes, College of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China
| | - Kaifeng Wang
- Department of Medical Oncology, Holistic Integrative Oncology Institutes and Holistic Integrative Cancer Center of Traditional Chinese and Western Medicine, The Affiliated Hospital of Hangzhou Normal University, College of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China; Department of Cancer Pharmacology, Holistic Integrative Pharmacy Institutes, College of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China
| | - Mang Xiao
- Department of Otolaryngology Head and Neck Surgery, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China.
| | - Tian Xie
- Department of Medical Oncology, Holistic Integrative Oncology Institutes and Holistic Integrative Cancer Center of Traditional Chinese and Western Medicine, The Affiliated Hospital of Hangzhou Normal University, College of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China; Department of Cancer Pharmacology, Holistic Integrative Pharmacy Institutes, College of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China; Key Laboratory of Elemene Class Anti-cancer Chinese Medicine of Zhejiang Province and Engineering Laboratory of Development and Application of Traditional Chinese Medicine from Zhejiang Province, Hangzhou Normal University, Hangzhou, Zhejiang, China.
| | - Xinbing Sui
- Department of Medical Oncology, Holistic Integrative Oncology Institutes and Holistic Integrative Cancer Center of Traditional Chinese and Western Medicine, The Affiliated Hospital of Hangzhou Normal University, College of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China; Department of Cancer Pharmacology, Holistic Integrative Pharmacy Institutes, College of Medicine, Hangzhou Normal University, Hangzhou, Zhejiang, China; Key Laboratory of Elemene Class Anti-cancer Chinese Medicine of Zhejiang Province and Engineering Laboratory of Development and Application of Traditional Chinese Medicine from Zhejiang Province, Hangzhou Normal University, Hangzhou, Zhejiang, China.
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14
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Rodríguez A, Ortega A. Glutamine/Glutamate Transporters in Glial Cells: Much More Than Participants of a Metabolic Shuttle. ADVANCES IN NEUROBIOLOGY 2017; 16:169-183. [PMID: 28828610 DOI: 10.1007/978-3-319-55769-4_8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Glial glutamine and glutamate transporters play an important role in glial/neuronal interactions. An excellent model to establish the role of these membrane proteins is the cerebellum. The most abundant glutamatergic synapse in the central nervous system is present in the molecular layer of the cerebellar cortex, and it is entirely wrapped by Bergmann glial cells. The recycling of glutamate involves glutamate and glutamine transporters enriched in these radial glial processes. The functional properties of amino acid glial transporters allow, in an activity-dependent manner, the conformation of protein complexes important for the adequate support of glutamatergic neurotransmission. A detailed description of the most important features of glial glutamate and glutamine transporters follows, and a working model of the molecular mechanisms by which these glutamate and glutamine binding proteins interact, and by these means might modulate cerebellar glutamatergic transactions, is presented.
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Affiliation(s)
- Angelina Rodríguez
- Facultad de Ciencias Naturales, Universidad Autónoma de Querétaro, Centro Universitario, Querétaro, México
| | - Arturo Ortega
- Departamento de Toxicología, Cinvestav-IPN, Apartado Postal 14-740, México, DF, 07360, México.
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15
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Jiang X, Jiang X, Feng Y, Xu R, Wang Q, Deng H. Proteomic Analysis of eIF5B Silencing-Modulated Proteostasis. PLoS One 2016; 11:e0168387. [PMID: 27959964 PMCID: PMC5154608 DOI: 10.1371/journal.pone.0168387] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 11/29/2016] [Indexed: 11/17/2022] Open
Abstract
Protein translational machinery is an important component of the proteostasis network that maintains cellular proteostasis and regulates aging and other cellular processes. Ample evidence indicates that inhibition of translation initiation factor activities enhances stress resistance in model organisms. Eukaryotic translation initiation factor 5B (eIF5B) acts by joining the pre-40S subunit with the 60S ribosomal unit to form an 80S-like complex during protein translational initiation. Reduced eIF5B expression may disrupt proteostasis and trigger cellular processes associated with stress responses. In this study, the physiological effects of altered eIF5B expression were examined in 293T and HepG2 cells. Cells with eIF5B-knockdown (eIF5B-KN) grew more slowly than control cells, and had a lower level of intracellular reactive oxygen species (ROS), increased resistance to oxidative stress and enhanced autophagy. Proteomic analysis showed that eIF5B knockdown resulted in upregulation of 88 proteins and downregulation of 130 proteins compared with control cells. The differentially expressed proteins were associated with diverse cellular processes including amino acid metabolism, RNA processing and protein metabolism, and DNA synthesis. Autonomous downregulation of the mitogen-activated protein kinase (MAPK) signaling pathway was identified as confirmed by western blotting and qPCR. We proposed that deactivation of MAPK pathway modulated proteostasis and induced prolonged S-phase of the cell-cycle, contributing to the slow growth of eIF5B-KN cells. eIF5B silencing also inactivated the mTOR pathway, downregulated glutamine transporters, enhanced autophagy, and decreased 28S rRNA and 5.8S rRNA expression levels which were reversed by restoration of eIF5B expression. Taken together, these results suggest that eIF5B silencing provides a negative feedback to deactivate MAPK signaling, leading to reduced cell growth. These findings provide a useful resource to further biological exploration of the functions of protein synthesis in regulation of proteostasis and stress responses.
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Affiliation(s)
- Xu Jiang
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, China
| | - Xiaoyong Jiang
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yun Feng
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, China
| | - Renhua Xu
- School of Nursing, Binzhou Medical University, Yantai, China
| | - Qingtao Wang
- Beijing Chaoyang Hospital Affiliated to Capital Medical University, Beijing, China
| | - Haiteng Deng
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, China
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16
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Timosenko E, Ghadbane H, Silk JD, Shepherd D, Gileadi U, Howson LJ, Laynes R, Zhao Q, Strausberg RL, Olsen LR, Taylor S, Buffa FM, Boyd R, Cerundolo V. Nutritional Stress Induced by Tryptophan-Degrading Enzymes Results in ATF4-Dependent Reprogramming of the Amino Acid Transporter Profile in Tumor Cells. Cancer Res 2016; 76:6193-6204. [PMID: 27651314 PMCID: PMC5096689 DOI: 10.1158/0008-5472.can-15-3502] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 08/26/2016] [Indexed: 01/08/2023]
Abstract
Tryptophan degradation is an immune escape strategy shared by many tumors. However, cancer cells' compensatory mechanisms remain unclear. We demonstrate here that a shortage of tryptophan caused by expression of indoleamine 2,3-dioxygenase (IDO) and tryptophan 2,3-dioxygenase (TDO) resulted in ATF4-dependent upregulation of several amino acid transporters, including SLC1A5 and its truncated isoforms, which in turn enhanced tryptophan and glutamine uptake. Importantly, SLC1A5 failed to be upregulated in resting human T cells kept under low tryptophan conditions but was enhanced upon cognate antigen T-cell receptor engagement. Our results highlight key differences in the ability of tumor and T cells to adapt to tryptophan starvation and provide important insights into the poor prognosis of tumors coexpressing IDO and SLC1A5. Cancer Res; 76(21); 6193-204. ©2016 AACR.
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Affiliation(s)
- Elina Timosenko
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Hemza Ghadbane
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Jonathan D Silk
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Dawn Shepherd
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Uzi Gileadi
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Lauren J Howson
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Robert Laynes
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Qi Zhao
- Ludwig Cancer Research, New York, New York
| | | | - Lars R Olsen
- Center for Biological Sequence Analysis, Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark
| | - Stephen Taylor
- The Computational Biology Research Group (CBRG), Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - Francesca M Buffa
- Department of Oncology, Old Road Campus Research Building, University of Oxford, Oxford, United Kingdom
| | - Richard Boyd
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Vincenzo Cerundolo
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom.
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17
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Console L, Scalise M, Tarmakova Z, Coe IR, Indiveri C. N-linked glycosylation of human SLC1A5 (ASCT2) transporter is critical for trafficking to membrane. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:1636-45. [PMID: 25862406 DOI: 10.1016/j.bbamcr.2015.03.017] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 03/26/2015] [Accepted: 03/31/2015] [Indexed: 12/11/2022]
Abstract
The human amino acid transporter SLC1A5 (ASCT2) contains two N-glycosylation sites (N163 and N212) located in the large extracellular loop. In the homology structural model of ASCT2 these Asn residues are extracellularly exposed. Mutants of the two Asn exhibited altered electrophoretic mobility. N163Q and N212Q displayed multiple bands with apparent molecular masses from 80kDa to 50kDa. N163/212Q displayed a single band of 50kDa corresponding to the unglycosylated protein. The presence in membrane of WT and mutants was evaluated by protein biotinylation assay followed by immunoblotting. The double mutation significantly impaired the presence of the protein in membrane, without impairment in protein synthesis. [(3)H]glutamine transport was measured in cells transiently transfected with the WT or mutants. N163/212Q exhibited a strongly reduced transport activity correlating with reduced surface expression. The same proteins extracted from cells and reconstituted in liposomes showed comparable transport activities demonstrating that the intrinsic transport function of the mutants was not affected. The rate of endocytosis of ASCT2 was assayed by a reversible biotinylation strategy. N212Q and N163/212Q showed strongly increased rates of endocytosis respect to WT. ASCT2 stability was determined using cycloheximide. N163Q or N163/212Q showed a slightly or significantly lower stability with respect to WT. To assess trafficking to the membrane, a brefeldin-based assay, which caused retention of proteins in ER, was performed. One hour after brefeldin removal WT protein was localized to the plasma membrane while the double mutant was localized in the cytosol. The results demonstrate that N-glycosylation is critical for trafficking.
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Affiliation(s)
- Lara Console
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via P. Bucci 4C, 87036 Arcavacata di Rende, Italy; Department of Chemistry and Biology, Ryerson University, 350 Victoria St., Toronto M5B 2K3, Canada
| | - Mariafrancesca Scalise
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via P. Bucci 4C, 87036 Arcavacata di Rende, Italy
| | - Zlatina Tarmakova
- Department of Chemistry and Biology, Ryerson University, 350 Victoria St., Toronto M5B 2K3, Canada
| | - Imogen R Coe
- Department of Chemistry and Biology, Ryerson University, 350 Victoria St., Toronto M5B 2K3, Canada
| | - Cesare Indiveri
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via P. Bucci 4C, 87036 Arcavacata di Rende, Italy
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18
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Zhou J, Fan S, Cao Y, Zhu M, Han Y, Cao X, Li Y. Tumor necrosis factor-α suppresses the protein fractional synthesis rate of the small intestine stimulated by glutamine in rats. Exp Ther Med 2014; 9:547-552. [PMID: 25574232 PMCID: PMC4280961 DOI: 10.3892/etm.2014.2129] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2014] [Accepted: 10/21/2014] [Indexed: 12/21/2022] Open
Abstract
The objective of this study was to examine whether and how TNF-α affects glutamine-enhanced protein synthesis and the expression of the amino acid transporter ASCT2 in the small intestine at the mRNA and protein levels. A total of 30 male Sprague-Dawley rats were randomly assigned into three groups, namely the total parenteral nutrition (TPN; control), glutamine-treated (Gln), and glutamine- and tumor necrosis factor-α (TNF-α)-treated (TNF-α) groups. At 30 min prior to examination, all rats were mainlined with [L-15N]leucine. The concentration of TNF-α in plasma and of glutamine in plasma and the small intestine was measured. The fractional synthesis rate (FSR) of protein and the mRNA and protein expression levels of ASCT2 in the small intestine were assessed. The level of TNF-α was highest in the TNF-α group and the glutamine concentration was elevated to a greater extent in the TNF-α group than in the other two groups. However, the FSR of protein in the small intestine was significantly higher in the Gln group compared with that in the TNF-α group. The mRNA and protein expression levels of ASCT2 in the experimental groups were significantly higher that those in the control group, but did not differ significantly between the Gln and TNF-α groups. These results indicate that TNF-α may attenuate glutamine-stimulated protein synthesis in the small intestine in the early stage of sepsis in rats. The mechanism may be that TNF-α inhibits the function of the glutamine transporter in the uptake the glutamine into target cells for protein synthesis. This inhibition may occur at or following protein translation.
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Affiliation(s)
- Jihong Zhou
- Department of Burns and Plastic Surgery, Jinling Hospital, Nanjing University School of Medicine, Nanjing, Jiangsu 210002, P.R. China
| | - Shengxian Fan
- Department of General Surgery, Jinling Hospital, Nanjing University School of Medicine, Nanjing, Jiangsu 210002, P.R. China
| | - Yacheng Cao
- Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu 210002, P.R. China
| | - Mingfang Zhu
- Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu 210002, P.R. China
| | - Yong Han
- Institute of Soil Science, Chinese Academy of Sciences, Nanjing, Jiangsu 210002, P.R. China
| | - Xueying Cao
- Department of Burns and Plastic Surgery, Jinling Hospital, Nanjing University School of Medicine, Nanjing, Jiangsu 210002, P.R. China
| | - Yousheng Li
- Department of General Surgery, Jinling Hospital, Nanjing University School of Medicine, Nanjing, Jiangsu 210002, P.R. China
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19
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Pochini L, Scalise M, Galluccio M, Indiveri C. Membrane transporters for the special amino acid glutamine: structure/function relationships and relevance to human health. Front Chem 2014; 2:61. [PMID: 25157349 PMCID: PMC4127817 DOI: 10.3389/fchem.2014.00061] [Citation(s) in RCA: 172] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 07/16/2014] [Indexed: 12/26/2022] Open
Abstract
Glutamine together with glucose is essential for body's homeostasis. It is the most abundant amino acid and is involved in many biosynthetic, regulatory and energy production processes. Several membrane transporters which differ in transport modes, ensure glutamine homeostasis by coordinating its absorption, reabsorption and delivery to tissues. These transporters belong to different protein families, are redundant and ubiquitous. Their classification, originally based on functional properties, has recently been associated with the SLC nomenclature. Function of glutamine transporters is studied in cells over-expressing the transporters or, more recently in proteoliposomes harboring the proteins extracted from animal tissues or over-expressed in microorganisms. The role of the glutamine transporters is linked to their transport modes and coupling with Na+ and H+. Most transporters share specificity for other neutral or cationic amino acids. Na+-dependent co-transporters efficiently accumulate glutamine while antiporters regulate the pools of glutamine and other amino acids. The most acknowledged glutamine transporters belong to the SLC1, 6, 7, and 38 families. The members involved in the homeostasis are the co-transporters B0AT1 and the SNAT members 1, 2, 3, 5, and 7; the antiporters ASCT2, LAT1 and 2. The last two are associated to the ancillary CD98 protein. Some information on regulation of the glutamine transporters exist, which, however, need to be deepened. No information at all is available on structures, besides some homology models obtained using similar bacterial transporters as templates. Some models of rat and human glutamine transporters highlight very similar structures between the orthologs. Moreover the presence of glycosylation and/or phosphorylation sites located at the extracellular or intracellular faces has been predicted. ASCT2 and LAT1 are over-expressed in several cancers, thus representing potential targets for pharmacological intervention.
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Affiliation(s)
- Lorena Pochini
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria Arcavacata di Rende, Italy
| | - Mariafrancesca Scalise
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria Arcavacata di Rende, Italy
| | - Michele Galluccio
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria Arcavacata di Rende, Italy
| | - Cesare Indiveri
- Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria Arcavacata di Rende, Italy
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20
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Transport mechanism and regulatory properties of the human amino acid transporter ASCT2 (SLC1A5). Amino Acids 2014; 46:2463-75. [DOI: 10.1007/s00726-014-1808-x] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 07/06/2014] [Indexed: 02/06/2023]
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21
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Wang B, Wu G, Zhou Z, Dai Z, Sun Y, Ji Y, Li W, Wang W, Liu C, Han F, Wu Z. Glutamine and intestinal barrier function. Amino Acids 2014; 47:2143-54. [PMID: 24965526 DOI: 10.1007/s00726-014-1773-4] [Citation(s) in RCA: 151] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 05/27/2014] [Indexed: 12/27/2022]
Abstract
The intestinal barrier integrity is essential for the absorption of nutrients and health in humans and animals. Dysfunction of the mucosal barrier is associated with increased gut permeability and development of multiple gastrointestinal diseases. Recent studies highlighted a critical role for glutamine, which had been traditionally considered as a nutritionally non-essential amino acid, in activating the mammalian target of rapamycin cell signaling in enterocytes. In addition, glutamine has been reported to enhance intestinal and whole-body growth, to promote enterocyte proliferation and survival, and to regulate intestinal barrier function in injury, infection, weaning stress, and other catabolic conditions. Mechanistically, these effects were mediated by maintaining the intracellular redox status and regulating expression of genes associated with various signaling pathways. Furthermore, glutamine stimulates growth of the small intestinal mucosa in young animals and also enhances ion transport by the gut in neonates and adults. Growing evidence supports the notion that glutamine is a nutritionally essential amino acid for neonates and a conditionally essential amino acid for adults. Thus, as a functional amino acid with multiple key physiological roles, glutamine holds great promise in protecting the gut from atrophy and injury under various stress conditions in mammals and other animals.
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Affiliation(s)
- Bin Wang
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, People's Republic of China
| | - Guoyao Wu
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, People's Republic of China.,Department of Animal Science, Texas A&M University, College Station, TX, 77843, USA
| | - Zhigang Zhou
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Zhaolai Dai
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, People's Republic of China
| | - Yuli Sun
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, People's Republic of China
| | - Yun Ji
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, People's Republic of China
| | - Wei Li
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, People's Republic of China
| | - Weiwei Wang
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, People's Republic of China
| | - Chuang Liu
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, People's Republic of China
| | - Feng Han
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, People's Republic of China
| | - Zhenlong Wu
- State Key Laboratory of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, 100193, People's Republic of China.
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22
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El-Gebali S, Bentz S, Hediger MA, Anderle P. Solute carriers (SLCs) in cancer. Mol Aspects Med 2013; 34:719-34. [PMID: 23506905 DOI: 10.1016/j.mam.2012.12.007] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 12/13/2012] [Indexed: 12/26/2022]
Abstract
During tumor progression cells acquire an altered metabolism, either as a cause or as a consequence of an increased need of energy and nutrients. All four major classes of macromolecules are affected: carbohydrates, proteins, lipids and nucleic acids. As a result of the changed needs, solute carriers (SLCs) which are the major transporters of these molecules are differently expressed. This renders them important targets in the treatment of cancer. Blocking or activating SLCs is one possible therapeutic strategy. For example, some SLCs are upregulated in tumor cells due to the increased demand for energy and nutritional needs. Thus, blocking them and turning off the delivery of fuel or nutrients could be one way to interfere with tumor progression. Specific drug delivery to cancer cells via transporters is another approach. Some SLCs are also interesting as chemosensitizing targets because blocking or activating them may result in an altered response to chemotherapy. In this review we summarize the roles of SLCs in cancer therapy and specifically their potential as direct or indirect targets, as drug carriers or as chemosensitizing targets.
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Affiliation(s)
- Sara El-Gebali
- Institute of Biochemistry and Molecular Medicine, University of Bern, Bern, Switzerland
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23
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Pingitore P, Pochini L, Scalise M, Galluccio M, Hedfalk K, Indiveri C. Large scale production of the active human ASCT2 (SLC1A5) transporter in Pichia pastoris--functional and kinetic asymmetry revealed in proteoliposomes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:2238-46. [PMID: 23756778 DOI: 10.1016/j.bbamem.2013.05.034] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2013] [Revised: 05/28/2013] [Accepted: 05/31/2013] [Indexed: 12/11/2022]
Abstract
The human glutamine/neutral amino acid transporter ASCT2 (hASCT2) was over-expressed in Pichia pastoris and purified by Ni(2+)-chelating and gel filtration chromatography. The purified protein was reconstituted in liposomes by detergent removal with a batch-wise procedure. Time dependent [(3)H]glutamine/glutamine antiport was measured in proteoliposomes which was active only in the presence of external Na(+). Internal Na(+) slightly stimulated the antiport. Optimal activity was found at pH7.0. A substantial inhibition of the transport was observed by Cys, Thr, Ser, Ala, Asn and Met (≥70%) and by mercurials and methanethiosulfonates (≥80%). Heterologous antiport of [(3)H]glutamine with other neutral amino acids was also studied. The transporter showed asymmetric specificity for amino acids: Ala, Cys, Val, Met were only inwardly transported, while Gln, Ser, Asn, and Thr were transported bi-directionally. From kinetic analysis of [(3)H]glutamine/glutamine antiport Km values of 0.097 and 1.8mM were measured on the external and internal sides of proteoliposomes, respectively. The Km for Na(+) on the external side was 32mM. The homology structural model of the hASCT2 protein was built using the GltPh of Pyrococcus horikoshii as template. Cys395 was the only Cys residue externally exposed, thus being the potential target of SH reagents inhibition and, hence, potentially involved in the transport mechanism.
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Affiliation(s)
- Piero Pingitore
- Department BEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via P. Bucci 4c, 87036 Arcavacata di Rende, Italy.
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24
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Saksena S, Priyamvada S, Kumar A, Akhtar M, Soni V, Anbazhagan AN, Alakkam A, Alrefai WA, Dudeja PK, Gill RK. Keratinocyte growth factor-2 stimulates P-glycoprotein expression and function in intestinal epithelial cells. Am J Physiol Gastrointest Liver Physiol 2013; 304:G615-22. [PMID: 23328208 PMCID: PMC3602685 DOI: 10.1152/ajpgi.00445.2012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Intestinal P-glycoprotein (Pgp/multidrug resistance 1), encoded by the ATP-binding cassette B1 gene, is primarily involved in the transepithelial efflux of toxic metabolites and xenobiotics from the mucosa into the gut lumen. Reduced Pgp function and expression has been shown to be associated with intestinal inflammatory disorders. Keratinocyte growth factor-2 (KGF2) has emerged as a potential target for modulation of intestinal inflammation and maintenance of gut mucosal integrity. Whether KGF2 directly regulates Pgp in the human intestine is not known. Therefore, the present studies were undertaken to determine the modulation of Pgp by KGF2 using Caco-2 cells. Short-term treatment of Caco-2 cells with KGF2 (10 ng/ml, 1 h) increased Pgp activity (~2-fold, P < 0.05) as measured by verapamil-sensitive [(3)H]digoxin flux. This increase in Pgp function was associated with an increase in surface Pgp levels. The specific fibroblast growth factor receptor (FGFR) antagonist PD-161570 blocked the KGF2-mediated increase in Pgp activity. Inhibition of the mitogen-activated protein kinase (MAPK) pathway by PD-98059 attenuated the stimulatory effects of KGF2 on Pgp activity. Small-interfering RNA knockdown of Erk1/2 MAPK blocked the increase in surface Pgp levels by KGF2. Long-term treatment with KGF2 (10 ng/ml, 24 h) also significantly increased PgP activity, mRNA, protein expression, and promoter activity. The long-term effects of KGF2 on Pgp promoter activity were also blocked by the FGFR antagonist and mediated by the Erk1/2 MAPK pathway. In conclusion, our findings define the posttranslational and transcriptional mechanisms underlying stimulation of Pgp function and expression by KGF2 that may contribute to the beneficial effects of KGF2 in intestinal inflammatory disorders.
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Affiliation(s)
- Seema Saksena
- Section of Digestive Diseases and Nutrition, Department of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA.
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Niederlechner S, Baird C, Petrie B, Wischmeyer E, Wischmeyer PE. Epidermal growth factor receptor expression and signaling are essential in glutamine's cytoprotective mechanism in heat-stressed intestinal epithelial-6 cells. Am J Physiol Gastrointest Liver Physiol 2013; 304:G543-52. [PMID: 23275616 PMCID: PMC3602678 DOI: 10.1152/ajpgi.00418.2012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Epidermal growth factor receptor (EGFR) expression and signaling can induce cellular protection after intestinal inflammation. L-Glutamine (GLN) is known to prevent apoptosis after intestinal injury by activating MAPK and phosphatidylinositol 3-kinase (PI3-K)/Akt pathways. However, the role of EGFR expression and signaling in GLN-mediated cellular protection in intestinal epithelial-6 (IEC-6) cells after heat stress (HS) is unknown. To address the role of EGFR in GLN-mediated protection, IEC-6 cells were treated with GLN in the presence or absence of EGFR small interfering RNA, the EGFR tyrosine kinase inhibitor AG1478, the ERK1/2 inhibitor PD98059, the p38MAPK inhibitor SB203580, or the PI3-K/Akt inhibitor LY294002 under basal and HS conditions. GLN-mediated cell survival was measured using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay. Phosphorylated and/or total levels of EGFR, cleaved caspase-3, poly(ADP-ribose) polymerase-1, ERK1/2, p38MAPK, and Akt were assessed by Western blotting. We showed that HS induced a decrease in total, cytoplasmic, and nuclear EGFR levels in IEC-6 cells, which was prevented by GLN supplementation, leading to attenuated apoptosis via EGFR small interfering RNA. Furthermore, the protective effect of GLN was lessened by AG1478, PD98059, and LY294002 but was not affected by SB203580. AG1478 attenuated GLN-mediated increases in ERK1/2 and decreases in p38MAPK phosphorylation. However, AG1478 had no effect on GLN-mediated augmentations in Akt phosphorylation. In summary, EGFR expression was important in the protective mechanism of GLN, as well as GLN-mediated activation of EGFR tyrosine kinase activity. GLN-mediated EGFR signaling activated ERK1/2 and decreased p38MAPK signaling. However, GLN-mediated Akt phosphorylation after HS seems to be independent of EGFR signaling.
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Affiliation(s)
| | - Christine Baird
- 1Department of Anesthesiology, University of Colorado, Colorado, Aurora, Colorado; and
| | - Benjamin Petrie
- 1Department of Anesthesiology, University of Colorado, Colorado, Aurora, Colorado; and
| | | | - Paul E. Wischmeyer
- 1Department of Anesthesiology, University of Colorado, Colorado, Aurora, Colorado; and
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Abstract
PURPOSE OF REVIEW We consider recent advances in epithelial amino acid transport physiology and our understanding of the functioning of amino acid transporters as sensors, as well as carriers, of tissue nutrient supplies. RECENT FINDINGS Gut hormones (e.g. leptin) may regulate intestinal amino acid transporter activity by a variety of mechanisms, although the overall functional significance of such regulation is not yet fully understood. Important functional interactions between amino acid transporters and nutrient-signalling pathways which regulate metabolism [e.g. the mammalian target of rapamycin (mTOR)C1 pathway which promotes cell growth] have been revealed in recent studies. Amino acid transporters on endosomal (e.g. lysosomal) membranes may be of unexpected significance as intracellular nutrient sensors. It is also now evident that certain amino acid transporters may have dual receptor-transporter functions and act as 'transceptors' to sense amino acid availability upstream of signal pathways. SUMMARY Increased knowledge on the timescale of the amino acid sensor-signal-effector process(es) should help in the optimization of protein-feeding regimes to gain maximum anabolic effect. New opportunities for nutritional therapy include targeting of amino acid transceptors to promote protein-anabolic signals and mechanisms up-regulating amino acid transporter expression to improve absorptive capacity for nutrients.
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Affiliation(s)
- Nadège Poncet
- Division of Cell Signalling & Immunology, College of Life Sciences, University of Dundee, Sir James Black Centre, Dundee, UK
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Hodges RR, Bair JA, Carozza RB, Li D, Shatos MA, Dartt DA. Signaling pathways used by EGF to stimulate conjunctival goblet cell secretion. Exp Eye Res 2012; 103:99-113. [PMID: 22975404 DOI: 10.1016/j.exer.2012.08.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Revised: 07/19/2012] [Accepted: 08/26/2012] [Indexed: 01/26/2023]
Abstract
The purpose of this study was to identify the signaling pathways that epidermal growth factor (EGF) uses to stimulate mucin secretion from cultured rat conjunctival goblet cells and to compare the pathways used by EGF with those used by the known secretagogue muscarinic, cholinergic agonists. To this end, goblet cells from rat conjunctiva were grown in culture using RPMI media. For immunofluorescence experiments, antibodies against EGF receptor (EGFR) and ERK 2 as well as muscarinic receptors (M(1)AchR, M(2)AchR, and M(3)AchR) were used, and the cells viewed by fluorescence microscopy. Intracellular [Ca(2+)] ([Ca(2+)](i)) was measured using fura 2/AM. Glycoconjugate secretion was determined after cultured goblet cells were preincubated with inhibitors, and then stimulated with EGF or the cholinergic agonist carbachol (Cch). Goblet cell secretion was measured using an enzyme-linked lectin assay with UEA-I or ELISA for MUC5AC. In cultured goblet cells EGF stimulated an increase in [Ca(2+)](i) in a concentration-dependent manner. EGF-stimulated increase in [Ca(2+)](i) was blocked by inhibitors of the EGF receptor and removal of extracellular Ca(2+). Inhibitors against the EGFR and ERK 1/2 blocked EGF-stimulated mucin secretion. In addition, cultured goblet cells expressed M(1)AchR, M(2)AchR, and M(3)AchRs. Cch-stimulated increase in [Ca(2+)](i) was blocked by inhibitors for the M(1)AchRs, matrix metalloproteinases, and EGF receptors. Inhibitors against the EGF receptor and ERK 1/2 also blocked Cch-stimulated mucin secretion. We conclude that in conjunctival goblet cells, EGF itself increases [Ca(2+)](i) and activates ERK 1/2 to stimulate mucin secretion. EGF-stimulated secretion is dependent on extracellular Ca(2+). This mechanism of action is similar to cholinergic agonists that use muscarinic receptors to transactivate the EGF receptor, increase [Ca(2+)](i), and activate ERK 1/2 leading to an increase in mucin secretion.
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Affiliation(s)
- Robin R Hodges
- Schepens Eye Research Institute, Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA
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Freeman MR, Kim J, Lisanti MP, Di Vizio D. A metabolic perturbation by U0126 identifies a role for glutamine in resveratrol-induced cell death. Cancer Biol Ther 2011; 12:966-77. [PMID: 22108021 DOI: 10.4161/cbt.12.11.18136] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Recent evidence has identified substantial overlap between metabolic and oncogenic biochemical pathways, suggesting novel approaches to cancer intervention. For example, cholesterol lowering statins and the antidiabetes medication metformin both act as chemopreventive agents in prostate and other cancers. The natural compound resveratrol has similar properties: increasing insulin sensitivity, suppressing adipogenesis, and inducing apoptotic death of cancer cells in vitro. However, in vivo tumor xenografts acquire resistance to resveratrol by an unknown mechanism, while mouse models of metabolic disorders respond more consistently to the compound. Here we demonstrate that castration-resistant human prostate cancer C4-2 cells are more sensitive to resveratrol-induced apoptosis than isogenic androgen-dependent LNCaP cells. The MEK inhibitor U0126 antagonized resveratrol-induced apoptosis in C4-2 cells, but this effect was not seen with other MEK inhibitors. U0126 was found to inhibit mitochondrial function and shift cells to aerobic glycolysis independently of MEK. Mitochondrial activity of U0126 arose through decomposition, producing both mitochondrial fluorescence and cyanide, a known inhibitor of complex IV. Applying U0126 mitochondrial inhibition to C4-2 cell apoptosis, we tested the possibility that glutamine supplementation of citric acid cycle intermediate α-ketoglutarate may be involved. Suppression of the conversion of glutamate to α-ketoglutarate antagonized resveratrol-induced death in C4-2 cells. A similar effect was also seen by reducing extracellular glutamine concentration in the culture medium, suggesting that resveratrol-induced death is dependent on glutamine metabolism, a process frequently dysregulated in cancer. Further work on resveratrol and metabolism in cancer is warranted to ascertain if the glutamine dependence has clinical implications.
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Affiliation(s)
- Michael R Freeman
- The Urological Diseases Research Center, Children's Hospital Boston, MA, USA.
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29
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Nakanishi T, Tamai I. Solute Carrier Transporters as Targets for Drug Delivery and Pharmacological Intervention for Chemotherapy. J Pharm Sci 2011; 100:3731-50. [DOI: 10.1002/jps.22576] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 03/29/2011] [Accepted: 03/31/2011] [Indexed: 01/11/2023]
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Nose K, Yang H, Sun X, Nose S, Koga H, Feng Y, Miyasaka E, Teitelbaum DH. Glutamine prevents total parenteral nutrition-associated changes to intraepithelial lymphocyte phenotype and function: a potential mechanism for the preservation of epithelial barrier function. J Interferon Cytokine Res 2010; 30:67-80. [PMID: 20028208 DOI: 10.1089/jir.2009.0046] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Total parenteral nutrition (TPN) results in a number of derangements to the intestinal epithelium, including a loss of epithelial barrier function (EBF). As TPN supplemented with glutamine has been thought to prevent this loss, this article further defined the impact of glutamine on EBF, and investigated potential mechanisms that contributed to the preservation of EBF. C57BL/6J male mice were randomized to enteral nutrition (control), TPN, or TPN supplemented with glutamine (TPN+GLN). Changes in intraepithelial lymphocyte (IEL)-derived cytokine expression were measured, and EBF was assessed with electrophysiologic methods and assessment of junctional protein expression. TPN resulted in a significant decline in EBF, and this loss of EBF was significantly prevented in the TPN+GLN group. Coincident with these changes was a loss of intraepithelial lymphocyte (IEL, mucosal lymphocyte)-derived IL-10 and increase in interferon-gamma (IFN-gamma) expression, and a decline in IEL numbers in the TPN group. A prevention in the increase in IFN-gamma and decline in IL-10 expression was seen in the TPN+GLN group. To determine the mechanism responsible for these glutamine-associated cytokine changes, we tested whether blockade of the IL-7 signaling pathway between epithelial cells (EC) and IEL would prevent these changes; however, blockade failed to influence IEL-derived cytokine changes. Glutamine-supplemented TPN leads to a specific IEL-derived cytokine profile, which may account for the preservation of EBF; and such action may be due to a direct action of glutamine on the IEL.
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Affiliation(s)
- Keisuke Nose
- Section of Pediatric Surgery, Department of Surgery, University of Michigan Medical School and the C.S. Mott Children's Hospital, Ann Arbor, Michigan 48109-0245, USA
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31
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Abstract
Autophagy, a conserved mechanism for lysosomal degradation of cytoplasmic components, has received much attention recently owing to its importance in tissue remodelling and innate immunity, and because it has been proposed that autophagy protects against cancer and neurodegenerative diseases. Although much of the molecular machinery that mediates autophagy has been identified, there are still aspects of this pathway that remain enigmatic. One open issue is the involvement of endosomal sorting complex required for transport (ESCRT) proteins, which were originally identified for their role in sorting ubiquitylated membrane proteins into multivesicular bodies. In this Opinion article, we discuss four possible models that could explain the observation that autophagosomes accumulate in ESCRT-depleted cells. We propose that the involvement of ESCRT proteins in the fusion of autophagosomes with the endolysosomal system is the most plausible model.
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Affiliation(s)
- Tor Erik Rusten
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, Montebello, N-0310 Oslo, Norway
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Zhang C, Feng Y, Yang H, Koga H, Teitelbaum DH. The bone morphogenetic protein signaling pathway is upregulated in a mouse model of total parenteral nutrition. J Nutr 2009; 139:1315-21. [PMID: 19498022 PMCID: PMC2696986 DOI: 10.3945/jn.108.096669] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2009] [Revised: 02/17/2009] [Accepted: 05/14/2009] [Indexed: 11/14/2022] Open
Abstract
Total parenteral nutrition (TPN) results in intestinal mucosal atrophic changes due to an absence of enteral nutrition; however, the mechanisms responsible for this are not fully understood. It has been shown that bone morphogenetic protein (BMP) activation inhibits intestinal epithelial cell (EC) proliferation. Therefore, we hypothesized that the BMP pathway could be upregulated by TPN. To address this, we randomly assigned mice to receive TPN or to be enterally fed (control) for 7 d. Mucosal EC isolates were harvested from the entire length of small intestine for RNA and protein measurements. Full-thickness, mid-small bowel was processed for histological examination. TPN increased the abundance of BMP2, BMP4, and BMP type II receptor at the RNA and protein levels. Phosphorylation of Smad1, Smad5, and Smad8 also was greater in the TPN group than in the control, which helped to confirm activation of this pathway. Interestingly, the TPN and control groups did not differ in the mRNA expression of the extracellular soluble bmp antagonists, noggin, gremlin, chordin, or follistatin. Compared to the control group, the expression of c-Myc (cellular myelocytomatosis) mRNA was lower, whereas the level of p21(WAF1/CIP1) was greater, in the TPN group. Because the BMP family may function through suppression of Wnt-beta-catenin signaling, this pathway was also examined. mRNA expression of Wnt 3, Wnt5a, and the Wnt receptor Lrp5 were lower in the TPN group compared to controls. The results suggest that the BMP signaling pathway may be involved in the development of intestinal mucosal atrophy due to TPN administration.
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Affiliation(s)
- Chaojun Zhang
- Section of Pediatric Surgery, Department of Surgery, University of Michigan Medical School and C. S. Mott Children's Hospital, Ann Arbor, MI 48109 and Department of General Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Yongjia Feng
- Section of Pediatric Surgery, Department of Surgery, University of Michigan Medical School and C. S. Mott Children's Hospital, Ann Arbor, MI 48109 and Department of General Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Hua Yang
- Section of Pediatric Surgery, Department of Surgery, University of Michigan Medical School and C. S. Mott Children's Hospital, Ann Arbor, MI 48109 and Department of General Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Hiroyuki Koga
- Section of Pediatric Surgery, Department of Surgery, University of Michigan Medical School and C. S. Mott Children's Hospital, Ann Arbor, MI 48109 and Department of General Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
| | - Daniel H. Teitelbaum
- Section of Pediatric Surgery, Department of Surgery, University of Michigan Medical School and C. S. Mott Children's Hospital, Ann Arbor, MI 48109 and Department of General Surgery, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China
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