1
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Gucenmez S, Yildiz P, Donderici O, Serter R. The effect of testosterone level on metabolic syndrome: a cross-sectional study. Hormones (Athens) 2024; 23:163-169. [PMID: 37981619 DOI: 10.1007/s42000-023-00507-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 11/07/2023] [Indexed: 11/21/2023]
Abstract
BACKGROUND Metabolic syndrome (MS) may reduce circulating testosterone and, at the same time, low testosterone levels may lead to MS. Thus, identifying problems regarding sex hormones and examining their effects on the pathogenesis of MS is important to prevent serious complications of the condition, such as diabetes or cardiovascular diseases. AIMS This study aimed to investigate the correlations between MS-related parameters and androgen levels. METHODS A total of 108 males [median age 48.5 years (min/max = 21/77 years)] were included in the study. Blood pressure and anthropometric measurements (body mass index, waist circumference, hip circumference, thigh circumference, neck circumference, and length of index and ring finger) were performed. Biochemical analysis was assessed. Additionally, total testosterone, free testosterone, and sex hormone binding globulin levels were investigated. RESULTS Weak negative correlations were observed between testosterone levels and several anthropometric measures/glucose metabolisms (p < 0.05). The highest correlation was between total testosterone levels and body mass index (rho= -0.390, p < 0.001) CONCLUSION: According to our results, controlling weight, one of the preventable risk factors, can have a positive effect on testosterone levels and, therefore, on the cardiovascular system through different mechanisms.
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Affiliation(s)
- Sercan Gucenmez
- Rheumatology Clinic, Ataturk Training and Research Hospital, Izmir Katip Celebi University, Izmir, Turkey.
| | - Pinar Yildiz
- Department of Internal Medicine, Faculty of Medicine, Eskisehir Osmangazi University, Eskisehir, Turkey
| | - Omer Donderici
- Internal Medicine Clinic, Ankara Training and Research Hospital, Ankara, Turkey
| | - Rustu Serter
- Department of Internal Medicine, Faculty of Medicine, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
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2
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Jiang X. An overview of the Plasmodium falciparum hexose transporter and its therapeutic interventions. Proteins 2022; 90:1766-1778. [PMID: 35445447 PMCID: PMC9790349 DOI: 10.1002/prot.26351] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 02/22/2022] [Accepted: 03/30/2022] [Indexed: 12/30/2022]
Abstract
Despite intense elimination efforts, human malaria, caused by the infection of five Plasmodium species, remains the deadliest parasitic disease in the world. Even worse, with the emergence and spreading of the first-line drug-resistant Plasmodium parasites, therapeutic interventions based on novel plasmodial drug targets are more necessary than ever. Given that the blood-stage parasites primarily rely on glycolysis for their energy supply, blocking glucose uptake, the rate-limiting step of ATP generation, was considered a promising approach to kill these parasites. To achieve this goal, characterization of the plasmodial hexose transporter and development of selective inhibitors have been pursued for decades. Here, we review the identification and characterization of the Plasmodium falciparum hexose transporter (PfHT1) and summarize current advances in its inhibitor development.
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Affiliation(s)
- Xin Jiang
- School of Biotechnology and Biomolecular Sciencesthe University of New South WalesSydneyNew South Wales
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3
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Miura K, Wen Y, Tsushima M, Nakamura H. Photodynamic Therapy by Glucose Transporter 1-Selective Light Inactivation. ACS OMEGA 2022; 7:34685-34692. [PMID: 36188330 PMCID: PMC9520747 DOI: 10.1021/acsomega.2c05042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Accepted: 09/07/2022] [Indexed: 06/16/2023]
Abstract
Chromophore-assisted light inactivation (CALI) was applied to molecule-targeted photodynamic therapy (PDT). In order to identify organic photosensitizers suitable for CALI, the carbonic anhydrase II (CAII) ligand, 4-sulfamoylbenzoic acid 1, was conjugated with several photosensitizers to produce compounds 2-7, whose CALI ability was evaluated by measuring their effect on CAII enzymatic activity. Di-iodinated BODIPY (I2BODIPY) exhibited excellent CAII inactivation ability, similar to that of Ru(bpy)3. The glucose-I2BODIPY conjugate (8) was synthesized as an inactivation of glucose transporter 1 (GLUT1), a protein overexpressed in many cancer cells. Under light irradiation, 8 exhibited concentration-dependent cytotoxicity with half maximal inhibitory concentration (IC50) values of 5.49, 11.14, and 8.73 μM, against human cervical carcinoma (HeLa), human lung carcinoma (A549), and human hepatocellular carcinoma (HepG2) cell lines, respectively. The GLUT1 inhibitor phloretin suppressed the cytotoxicity induced by 8 under light irradiation in a concentration-dependent manner. Western blot analysis indicated that GLUT1 was not detected in cell lines treated with 10 μM 8 under light irradiation. Furthermore, 8 reduced the levels of epidermal growth factor receptor tyrosine kinase (EGFR), phospho-ERK (Y204), and GLUT1 without affecting ERK, α-tubulin, and PCNA protein levels, whereas talaporfin sodium, a clinically approved photosensitizer for PDT, nonspecifically reduced intracellular protein levels in HeLa cells, indicating that 8 has a GLUT1-specific inactivation ability and causes light-induced cytotoxicity by modulating the EGFR/MAPK signaling pathway.
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Affiliation(s)
- Kazuki Miura
- Laboratory
for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
| | - Yijin Wen
- School
of Life Science and Technology, Tokyo Institute
of Technology, 4259 Nagatsuta-cho,
Midori-ku, Yokohama 226-8501, Japan
| | - Michihiko Tsushima
- School
of Life Science and Technology, Tokyo Institute
of Technology, 4259 Nagatsuta-cho,
Midori-ku, Yokohama 226-8501, Japan
| | - Hiroyuki Nakamura
- Laboratory
for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama 226-8503, Japan
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4
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Zhang X, Pang X, Zhang Z, Liu Q, Zhang H, Xiang Q, Cui Y. Co-expression and prognosis analyses of GLUT1-4 and RB1 in breast cancer. BMC Cancer 2021; 21:1026. [PMID: 34525987 PMCID: PMC8442321 DOI: 10.1186/s12885-021-08763-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 08/31/2021] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Current treatment methods for patients with triple-negative breast cancer (TNBC) are very limited, and the prognosis of TNBC is relatively poor. It has been reported that glucose transporter 1 (GLUT1) is overexpressed in breast cancer cells; however, its association with the prognosis is mostly unclear. Moreover, retinoblastoma gene 1 (RB1) might be used as a biomarker for the sensitivity of breast cancer cells to GLUT1 inhibitors, which brought us to the hypothesis that there might be a close correlation between the expression of GLUT1-4 and the expression of RB1. METHODS In this study, we systematically analyzed the co-expression of GLUT1-4 and the influence of GLUT1-4 gene expression on the prognosis of breast cancer using data mining methods. We also explored possible relationships between GLUT1-4 and RB1 expression in breast cancer tissues. We used public databases such as ONCOMINE, GEPIA, LinkedOmics, and COEXPEDIA. RESULTS According to the results, the mRNA expression of SLC2A1 was significantly higher in breast cancer, while the expression levels of SLC2A2-4 were downregulated. The results also indicate that GLUT1 expression does not have significant influence on the overall survival of patients with breast cancer. The mRNA expression of SLC2A1 and RB1 is significantly correlated, which means that tissues with high RB1 mRNA expression might have relatively higher mRNA expression of SLC2A1; however, further study analyzing their roles in the expression regulation pathways with human samples is needed to verify the hypothesis. CONCLUSIONS The mRNA expression of SLC2A1 was significantly higher in breast cancer. The overall survival of breast cancer patients wasn't significantly correlated with GLUT1-4 expression. The mRNA expression of SLC2A1 and RB1 is significantly correlated according to the analysis conducted in LinkedOmics. It provides reference for future possible individualized treatment of TNBC using GLUT1 inhibitors, especially in patients with higher mRNA expression of RB1. Further study analyzing the roles of these two genes in the regulation pathways is needed.
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Affiliation(s)
- Xiaodan Zhang
- Department of Pharmacy, Base for Clinical Trial, Peking University First Hospital, No. 8, Xishku Street, Beijing, 100034, P. R. China
| | - Xiaocong Pang
- Department of Pharmacy, Base for Clinical Trial, Peking University First Hospital, No. 8, Xishku Street, Beijing, 100034, P. R. China
| | - Zhuo Zhang
- Department of Pharmacy, Base for Clinical Trial, Peking University First Hospital, No. 8, Xishku Street, Beijing, 100034, P. R. China
| | - Qianxin Liu
- Department of Pharmacy, Base for Clinical Trial, Peking University First Hospital, No. 8, Xishku Street, Beijing, 100034, P. R. China
| | - Hanxu Zhang
- Department of Pharmacy, Base for Clinical Trial, Peking University First Hospital, No. 8, Xishku Street, Beijing, 100034, P. R. China
- Department of Pharmacy Administration and Clinical Pharmacy, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing, 100191, P. R. China
| | - Qian Xiang
- Department of Pharmacy, Base for Clinical Trial, Peking University First Hospital, No. 8, Xishku Street, Beijing, 100034, P. R. China.
| | - Yimin Cui
- Department of Pharmacy, Base for Clinical Trial, Peking University First Hospital, No. 8, Xishku Street, Beijing, 100034, P. R. China.
- Institute of Clinical Pharmacology, Peking University, No.38, Xue Yuan Street, Haidian District, Beijing, 100191, China.
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5
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Tan KN, Avery VM, Carrasco-Pozo C. Metabolic Roles of Androgen Receptor and Tip60 in Androgen-Dependent Prostate Cancer. Int J Mol Sci 2020; 21:ijms21186622. [PMID: 32927797 PMCID: PMC7555377 DOI: 10.3390/ijms21186622] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 09/08/2020] [Accepted: 09/09/2020] [Indexed: 01/10/2023] Open
Abstract
Androgen receptor (AR)-mediated signaling is essential for the growth and differentiation of the normal prostate and is the primary target for androgen deprivation therapy in prostate cancer. Tat interactive protein 60 kDa (Tip60) is a histone acetyltransferase that is critical for AR activation. It is well known that cancer cells rewire their metabolic pathways in order to sustain aberrant proliferation. Growing evidence demonstrates that the AR and Tip60 modulate key metabolic processes to promote the survival of prostate cancer cells, in addition to their classical roles. AR activation enhances glucose metabolism, including glycolysis, tricarboxylic acid cycle and oxidative phosphorylation, as well as lipid metabolism in prostate cancer. The AR also interacts with other metabolic regulators, including calcium/calmodulin-dependent kinase kinase 2 and mammalian target of rapamycin. Several studies have revealed the roles of Tip60 in determining cell fate indirectly by modulating metabolic regulators, such as c-Myc, hypoxia inducible factor 1α (HIF-1α) and p53 in various cancer types. Furthermore, Tip60 has been shown to regulate the activity of key enzymes in gluconeogenesis and glycolysis directly through acetylation. Overall, both the AR and Tip60 are master metabolic regulators that mediate cellular energy metabolism in prostate cancer, providing a framework for the development of novel therapeutic targets in androgen-dependent prostate cancer.
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Affiliation(s)
- Kah Ni Tan
- Discovery Biology, Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD 4111, Australia; (K.N.T.); (V.M.A.)
- CRC for Cancer Therapeutics, Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD 4111, Australia
| | - Vicky M. Avery
- Discovery Biology, Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD 4111, Australia; (K.N.T.); (V.M.A.)
- CRC for Cancer Therapeutics, Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD 4111, Australia
| | - Catalina Carrasco-Pozo
- Discovery Biology, Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD 4111, Australia; (K.N.T.); (V.M.A.)
- CRC for Cancer Therapeutics, Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD 4111, Australia
- Correspondence: ; Tel.: +617-3735-6034
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6
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Guizouarn H, Allegrini B. Erythroid glucose transport in health and disease. Pflugers Arch 2020; 472:1371-1383. [PMID: 32474749 DOI: 10.1007/s00424-020-02406-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 05/15/2020] [Accepted: 05/22/2020] [Indexed: 12/14/2022]
Abstract
Glucose transport is intimately linked to red blood cell physiology. Glucose is the unique energy source for these cells, and defects in glucose metabolism or transport activity are associated with impaired red blood cell morphology and deformability leading to reduced lifespan. In vertebrate erythrocytes, glucose transport is mediated by GLUT1 (in humans) or GLUT4 transporters. These proteins also account for dehydroascorbic acid (DHA) transport through erythrocyte membrane. The peculiarities of glucose transporters and the red blood cell pathologies involving GLUT1 are summarized in the present review.
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Affiliation(s)
- Hélène Guizouarn
- Université Côte d'Azur, CNRS, Inserm, Institut de Biologie Valrose, 28 av. Valrose, 06100, Nice, France.
| | - Benoit Allegrini
- Université Côte d'Azur, CNRS, Inserm, Institut de Biologie Valrose, 28 av. Valrose, 06100, Nice, France
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7
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Chemical biology probes of mammalian GLUT structure and function. Biochem J 2018; 475:3511-3534. [PMID: 30459202 PMCID: PMC6243331 DOI: 10.1042/bcj20170677] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 10/11/2018] [Accepted: 10/11/2018] [Indexed: 12/14/2022]
Abstract
The structure and function of glucose transporters of the mammalian GLUT family of proteins has been studied over many decades, and the proteins have fascinated numerous research groups over this time. This interest is related to the importance of the GLUTs as archetypical membrane transport facilitators, as key limiters of the supply of glucose to cell metabolism, as targets of cell insulin and exercise signalling and of regulated membrane traffic, and as potential drug targets to combat cancer and metabolic diseases such as type 2 diabetes and obesity. This review focusses on the use of chemical biology approaches and sugar analogue probes to study these important proteins.
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8
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Ojelabi OA, Lloyd KP, De Zutter JK, Carruthers A. Red wine and green tea flavonoids are cis-allosteric activators and competitive inhibitors of glucose transporter 1 (GLUT1)-mediated sugar uptake. J Biol Chem 2018; 293:19823-19834. [PMID: 30361436 DOI: 10.1074/jbc.ra118.002326] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 10/19/2018] [Indexed: 12/11/2022] Open
Abstract
The antioxidant- and flavonoid-rich contents of red wine and green tea are reported to offer protection against cancer, cardiovascular disease, and diabetes. Some studies, however, show that flavonoids inhibit GLUT1-mediated, facilitative glucose transport, raising the possibility that their interaction with GLUT1 and subsequent downstream effects on carbohydrate metabolism may also impact health. The present study explores the structure-function relationships of flavonoid-GLUT1 interactions. We find that low concentrations of flavonoids act as cis-allosteric activators of sugar uptake, whereas higher concentrations competitively inhibit sugar uptake and noncompetitively inhibit sugar exit. Studies with heterologously expressed human GLUT1, -3, or -4 reveal that quercetin-GLUT1 and -GLUT4 interactions are stronger than quercetin-GLUT3 interactions, that epicatechin gallate (ECG) is more selective for GLUT1, and that epigallocatechin gallate (EGCG) is less GLUT isoform-selective. Docking studies suggest that only one flavonoid can bind to GLUT1 at any instant, but sugar transport and ligand-binding studies indicate that human erythrocyte GLUT1 can bind at least two flavonoid molecules simultaneously. Quercetin and EGCG are each characterized by positive, cooperative binding, whereas ECG shows negative cooperative binding. These findings support recent studies suggesting that GLUT1 forms an oligomeric complex of interacting, allosteric, alternating access transporters. We discuss how modulation of facilitative glucose transporters could contribute to the protective actions of the flavonoids against diabetes and Alzheimer's disease.
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Affiliation(s)
- Ogooluwa A Ojelabi
- From the Department of Biochemistry and Molecular Pharmacology, Graduate School of Biomedical Sciences, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Kenneth P Lloyd
- From the Department of Biochemistry and Molecular Pharmacology, Graduate School of Biomedical Sciences, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Julie K De Zutter
- From the Department of Biochemistry and Molecular Pharmacology, Graduate School of Biomedical Sciences, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Anthony Carruthers
- From the Department of Biochemistry and Molecular Pharmacology, Graduate School of Biomedical Sciences, University of Massachusetts Medical School, Worcester, Massachusetts 01605
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9
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Gonzalez-Menendez P, Hevia D, Mayo JC, Sainz RM. The dark side of glucose transporters in prostate cancer: Are they a new feature to characterize carcinomas? Int J Cancer 2017; 142:2414-2424. [DOI: 10.1002/ijc.31165] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 11/01/2017] [Accepted: 11/15/2017] [Indexed: 12/12/2022]
Affiliation(s)
- Pedro Gonzalez-Menendez
- Department of Morphology and Cell Biology; Redox Biology Unit, University Institute of Oncology of Asturias (IUOPA). University of Oviedo. Facultad de Medicina.; Oviedo Spain
| | - David Hevia
- Department of Morphology and Cell Biology; Redox Biology Unit, University Institute of Oncology of Asturias (IUOPA). University of Oviedo. Facultad de Medicina.; Oviedo Spain
| | - Juan C. Mayo
- Department of Morphology and Cell Biology; Redox Biology Unit, University Institute of Oncology of Asturias (IUOPA). University of Oviedo. Facultad de Medicina.; Oviedo Spain
| | - Rosa M. Sainz
- Department of Morphology and Cell Biology; Redox Biology Unit, University Institute of Oncology of Asturias (IUOPA). University of Oviedo. Facultad de Medicina.; Oviedo Spain
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10
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Wu R, Zhu K, Zhang X, Zhang S, Liu Y, Ren J, Li C, Ye M, Ling X. Nonimmobilized Biomaterial Capillary Electrophoresis for Screening Drugs Targeting Human Glucose Transporter 1. Anal Chem 2017; 89:12951-12959. [PMID: 29099175 DOI: 10.1021/acs.analchem.7b03811] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
We report an online ligand screening method that targets human glucose transporter 1 (hGlut1) under approximately physiological conditions, named nonimmobilized biomaterial capillary electrophoresis (NIBCE), and we investigated the interactions between drugs/candidate compounds and HEK293 cells, hGlut1-overexpressing HEK293 cells, non-small-cell lung cancer A549 cells, A549 tumor tissue, and normal lung tissue by simulating the interactions between drugs and moving target cells or the space-occupying tumor. NIBCE omits the trouble of isolating and purifying target receptors from cell membrane while maintaining their native conformation and binding activity. The biomaterials were intercepted by porous frits in capillary columns and cannot flow through the detection window, thereby solving the problem of interference detection, and they can be renewed any time flexibly, thus effectively maintaining their surface bioactivity. Furthermore, the binding kinetic parameters (K, ka, kd, and k') were calculated by nonlinear chromatography (NLC) theory, and competitive binding experiments, ligand docking studies, and antitumor activity assays in vitro and in vivo were performed to verify the feasibility of NIBCE.
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Affiliation(s)
- Ruijun Wu
- The State Key Laboratory of Natural and Biomimetic Drugs and School of Pharmaceutical Sciences, Peking University , Beijing 100191, People's Republic of China
| | - Kai Zhu
- The State Key Laboratory of Natural and Biomimetic Drugs and School of Pharmaceutical Sciences, Peking University , Beijing 100191, People's Republic of China
| | - Xiaodan Zhang
- The State Key Laboratory of Natural and Biomimetic Drugs and School of Pharmaceutical Sciences, Peking University , Beijing 100191, People's Republic of China
| | - Sufang Zhang
- The State Key Laboratory of Natural and Biomimetic Drugs and School of Pharmaceutical Sciences, Peking University , Beijing 100191, People's Republic of China
| | - Yanmeng Liu
- The State Key Laboratory of Natural and Biomimetic Drugs and School of Pharmaceutical Sciences, Peking University , Beijing 100191, People's Republic of China
| | - Jinyu Ren
- The State Key Laboratory of Natural and Biomimetic Drugs and School of Pharmaceutical Sciences, Peking University , Beijing 100191, People's Republic of China
| | - Cong Li
- The State Key Laboratory of Natural and Biomimetic Drugs and School of Pharmaceutical Sciences, Peking University , Beijing 100191, People's Republic of China
| | - Min Ye
- The State Key Laboratory of Natural and Biomimetic Drugs and School of Pharmaceutical Sciences, Peking University , Beijing 100191, People's Republic of China
| | - Xiaomei Ling
- The State Key Laboratory of Natural and Biomimetic Drugs and School of Pharmaceutical Sciences, Peking University , Beijing 100191, People's Republic of China
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11
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Peluso I, Serafini M. Antioxidants from black and green tea: from dietary modulation of oxidative stress to pharmacological mechanisms. Br J Pharmacol 2017; 174:1195-1208. [PMID: 27747873 PMCID: PMC5429329 DOI: 10.1111/bph.13649] [Citation(s) in RCA: 130] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 09/12/2016] [Accepted: 09/29/2016] [Indexed: 12/15/2022] Open
Abstract
The consumption of tea (Camellia sinensis) has been correlated with a low incidence of chronic pathologies, such as cardiovascular disease and cancer, in which oxidative stress plays a critical role. Tea catechins and theaflavins are, respectively, the bioactive phytochemicals responsible for the antioxidant activity of green tea (GT) and black tea (BT). In addition to their redox properties, tea catechins and theaflavins could have also pharmacological activities, such as the ability to lower glucose, lipid and uric acid (UA) levels. These activities are mediated by pharmacological mechanisms such as enzymatic inhibition and interaction with transporters. Epigallocatechin gallate is the most active compound at inhibiting the enzymes involved in cholesterol and UA metabolism (hydroxy-3-methyl-glutaryl-CoA reductase and xanthine oxidase respectively) and affecting glucose transporters. The structural features of catechins that significantly contribute to their pharmacological effect are the presence/absence of the galloyl moiety and the number and positions of the hydroxyl groups on the rings. Although the inhibitory effects on α-glucosidase, maltase, amylase and lipase, multidrug resistance 1, organic anion transporters and proton-coupled folate transport occur at higher concentrations than those apparent in the circulation, these effects could be relevant in the gut. In conclusion, despite the urgent need for further research in humans, the regular consumption of moderate quantities of GT and BT can effectively modulate their antioxidant capacity, mainly in people subjected to oxidative stress, and could improve the metabolism of glucose, lipid and UA. LINKED ARTICLES This article is part of a themed section on Principles of Pharmacological Research of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.11/issuetoc.
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Affiliation(s)
- Ilaria Peluso
- Functional Foods and Metabolic Stress Prevention Laboratory, Centre for Food and NutritionCouncil for Agricultural Research and EconomicsRomeItaly
| | - Mauro Serafini
- Functional Foods and Metabolic Stress Prevention Laboratory, Centre for Food and NutritionCouncil for Agricultural Research and EconomicsRomeItaly
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12
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Filippopoulou K, Papaevgeniou N, Lefaki M, Paraskevopoulou A, Biedermann D, Křen V, Chondrogianni N. 2,3-Dehydrosilybin A/B as a pro-longevity and anti-aggregation compound. Free Radic Biol Med 2017; 103:256-267. [PMID: 28039083 DOI: 10.1016/j.freeradbiomed.2016.12.042] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 12/12/2016] [Accepted: 12/27/2016] [Indexed: 02/08/2023]
Abstract
Aging is an unavoidable process characterized by gradual failure of homeostasis that constitutes a critical risk factor for several age-related disorders. It has been unveiled that manipulation of various key pathways may decelerate the aging progression and the triggering of age-related diseases. As a consequence, the identification of compounds, preferably natural-occurring, administered through diet, with lifespan-extending, anti-aggregation and anti-oxidation properties that in parallel exhibit negligible side-effects is the main goal in the battle against aging. Here we analyze the role of 2,3-dehydrosilybin A/B (DHS A/B), a minor component of silymarin used in a plethora of dietary supplements. This flavonolignan is well-known for its anti-oxidative and neuroprotective properties, among others. We demonstrate that DHS A/B confers oxidative stress resistance not only in human primary cells but also in the context of a multi-cellular aging model, namely Caenorhabditis elegans (C. elegans) where it also promotes lifespan extension. We reveal that these DHS A/B outcomes are FGT-1 and DAF-16 dependent. We additionally demonstrate the anti-aggregation properties of DHS A/B in human cells of nervous origin but also in nematode models of Alzheimer's disease (AD), eventually leading to decelerated progression of AD phenotype. Our results identify DHS A/B as the active component of silymarin extract and propose DHS A/B as a candidate anti-aging and anti-aggregation compound.
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Affiliation(s)
- Konstantina Filippopoulou
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., Athens 11635, Greece
| | - Nikoletta Papaevgeniou
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., Athens 11635, Greece; Institute of Nutrition, Faculty of Biology and Pharmacy, Friedrich Schiller University of Jena, 25 Dornburger Str., 07743 Jena , Germany
| | - Maria Lefaki
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., Athens 11635, Greece
| | - Anna Paraskevopoulou
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., Athens 11635, Greece
| | - David Biedermann
- Institute of Microbiology, Laboratory of Biotransformation, Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague, Czech Republic
| | - Vladimír Křen
- Institute of Microbiology, Laboratory of Biotransformation, Czech Academy of Sciences, Vídeňská 1083, 142 20 Prague, Czech Republic
| | - Niki Chondrogianni
- Institute of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., Athens 11635, Greece.
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13
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Gao X, Liu S, Shi Y, Huang Z, Mi Y, Mi Q, Yang J, Gao Q. Mechanistic and biological characteristics of different sugar conjugated 2-methyl malonatoplatinum(II) complexes as new tumor targeting agents. Eur J Med Chem 2017; 125:372-384. [DOI: 10.1016/j.ejmech.2016.09.047] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 09/03/2016] [Accepted: 09/06/2016] [Indexed: 10/21/2022]
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14
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Ojelabi OA, Lloyd KP, Simon AH, De Zutter JK, Carruthers A. WZB117 (2-Fluoro-6-(m-hydroxybenzoyloxy) Phenyl m-Hydroxybenzoate) Inhibits GLUT1-mediated Sugar Transport by Binding Reversibly at the Exofacial Sugar Binding Site. J Biol Chem 2016; 291:26762-26772. [PMID: 27836974 DOI: 10.1074/jbc.m116.759175] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 11/10/2016] [Indexed: 01/26/2023] Open
Abstract
WZB117 (2-fluoro-6-(m-hydroxybenzoyloxy) phenyl m-hydroxybenzoate) inhibits passive sugar transport in human erythrocytes and cancer cell lines and, by limiting glycolysis, inhibits tumor growth in mice. This study explores how WZB117 inhibits the erythrocyte sugar transporter glucose transport protein 1 (GLUT1) and examines the transporter isoform specificity of inhibition. WZB117 reversibly and competitively inhibits erythrocyte 3-O-methylglucose (3MG) uptake with Ki(app) = 6 μm but is a noncompetitive inhibitor of sugar exit. Cytochalasin B (CB) is a reversible, noncompetitive inhibitor of 3MG uptake with Ki(app) = 0.3 μm but is a competitive inhibitor of sugar exit indicating that WZB117 and CB bind at exofacial and endofacial sugar binding sites, respectively. WZB117 inhibition of GLUTs expressed in HEK293 cells follows the order of potency: insulin-regulated GLUT4 ≫ GLUT1 ≈ neuronal GLUT3. This may explain WZB117-induced murine lipodystrophy. Molecular docking suggests the following. 1) The WZB117 binding envelopes of exofacial GLUT1 and GLUT4 conformers differ significantly. 2) GLUT1 and GLUT4 exofacial conformers present multiple, adjacent glucose binding sites that overlap with WZB117 binding envelopes. 3) The GLUT1 exofacial conformer lacks a CB binding site. 4) The inward GLUT1 conformer presents overlapping endofacial WZB117, d-glucose, and CB binding envelopes. Interrogating the GLUT1 mechanism using WZB117 reveals that subsaturating WZB117 and CB stimulate erythrocyte 3MG uptake. Extracellular WZB117 does not affect CB binding to GLUT1, but intracellular WZB117 inhibits CB binding. These findings are incompatible with the alternating conformer carrier for glucose transport but are consistent with either a multisubunit, allosteric transporter, or a transporter in which each subunit presents multiple, interacting ligand binding sites.
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Affiliation(s)
- Ogooluwa A Ojelabi
- From the Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Kenneth P Lloyd
- From the Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Andrew H Simon
- From the Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Julie K De Zutter
- From the Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605
| | - Anthony Carruthers
- From the Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts 01605
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15
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Fluorescent 6-amino-6-deoxyglycoconjugates for glucose transporter mediated bioimaging. Biochem Biophys Res Commun 2016; 480:341-347. [DOI: 10.1016/j.bbrc.2016.10.045] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 10/15/2016] [Indexed: 11/19/2022]
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16
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Ung PMU, Song W, Cheng L, Zhao X, Hu H, Chen L, Schlessinger A. Inhibitor Discovery for the Human GLUT1 from Homology Modeling and Virtual Screening. ACS Chem Biol 2016; 11:1908-16. [PMID: 27128978 DOI: 10.1021/acschembio.6b00304] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The human Glucose Transporter 1 (hGLUT1 or SLC2A1) is a facilitative membrane transporter found in the liver, intestines, kidney, and brain, where it transports sugars such as d-glucose and d-galactose. Genetic variations in hGLUT1 are associated with a broad range of diseases and metabolic disorders. For example, hGLUT1 is upregulated in various cancer types (e.g., breast carcinoma) to support the increased anaerobic glycolysis and the Warburg effect. Thus, hGLUT1 is an emerging therapeutic target, which also transports commonly used cancer biomarkers (e.g., (18)F-DG). In this study, we use computational prediction followed by experimental testing, to characterize hGLUT1. We construct homology models of hGLUT1 in a partially occluded outward open ("occluded") conformation based on the X-ray structure of the E. coli xylose transporter, XylE. Comparison of the binding site of the occluded models to experimentally determined hGLUT structures revealed a hydrophobic pocket adjacent to the sugar-binding site, which was tested experimentally via site-directed mutagenesis. Virtual screening of various libraries of purchasable compounds against the occluded models, followed by experimental testing with cellular assays revealed seven previously unknown hGLUT1 ligands with IC50 values ranging from 0.45 μM to 59 μM. These ligands represent three unique chemotypes that are chemically different from any other known hGLUT1 ligands. The newly characterized hydrophobic pocket can potentially be utilized by the new ligands for increased affinity. Furthermore, the previously unknown hGLUT1 ligands can serve as chemical tools to further characterize hGLUT1 function or lead molecules for future drug development.
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Affiliation(s)
- Peter Man-Un Ung
- Department
of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
| | - Wenxin Song
- School
of Pharmaceutical Sciences, Tsinghua University, Beijing, China 100084
| | - Lili Cheng
- School
of Pharmaceutical Sciences, Tsinghua University, Beijing, China 100084
| | - Xinbin Zhao
- School
of Pharmaceutical Sciences, Tsinghua University, Beijing, China 100084
| | - Hailin Hu
- School
of Pharmaceutical Sciences, Tsinghua University, Beijing, China 100084
| | - Ligong Chen
- School
of Pharmaceutical Sciences, Tsinghua University, Beijing, China 100084
| | - Avner Schlessinger
- Department
of Pharmacology and Systems Therapeutics, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
- Department
of Structural and Chemical Biology, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
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17
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Li T, Gao X, Yang L, Shi Y, Gao Q. Methyl 6-Amino-6-deoxy-d-pyranoside-Conjugated Platinum(II) Complexes for Glucose Transporter (GLUT)-Mediated Tumor Targeting: Synthesis, Cytotoxicity, and Cellular Uptake Mechanism. ChemMedChem 2016; 11:1069-77. [DOI: 10.1002/cmdc.201600079] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Indexed: 01/28/2023]
Affiliation(s)
- Taoli Li
- Tianjin Key Laboratory for Modern Drug Delivery & High Efficiency; Collaborative Innovation Center of Chemical Science and Engineering; School of Pharmaceutical Science and Technology; Tianjin University; 92 Weijin Road, Nankai District Tianjin 300072 P.R. China
| | - Xiangqian Gao
- Tianjin Key Laboratory for Modern Drug Delivery & High Efficiency; Collaborative Innovation Center of Chemical Science and Engineering; School of Pharmaceutical Science and Technology; Tianjin University; 92 Weijin Road, Nankai District Tianjin 300072 P.R. China
| | - Liu Yang
- Department of Biochemistry; Gudui BioPharma Technology Inc.; 5 Lanyuan Road, Huayuan Industrial Park Tianjin 300384 P.R. China
| | - Yunli Shi
- Tianjin Key Laboratory for Modern Drug Delivery & High Efficiency; Collaborative Innovation Center of Chemical Science and Engineering; School of Pharmaceutical Science and Technology; Tianjin University; 92 Weijin Road, Nankai District Tianjin 300072 P.R. China
| | - Qingzhi Gao
- Tianjin Key Laboratory for Modern Drug Delivery & High Efficiency; Collaborative Innovation Center of Chemical Science and Engineering; School of Pharmaceutical Science and Technology; Tianjin University; 92 Weijin Road, Nankai District Tianjin 300072 P.R. China
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18
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Cyanine-based 1-amino-1-deoxyglucose as fluorescent probes for glucose transporter mediated bioimaging. Biochem Biophys Res Commun 2016; 474:240-246. [DOI: 10.1016/j.bbrc.2016.03.133] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Accepted: 03/27/2016] [Indexed: 02/04/2023]
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19
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Galactose conjugated platinum(II) complex targeting the Warburg effect for treatment of non-small cell lung cancer and colon cancer. Eur J Med Chem 2016; 110:32-42. [PMID: 26807543 DOI: 10.1016/j.ejmech.2016.01.016] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Revised: 01/11/2016] [Accepted: 01/11/2016] [Indexed: 11/23/2022]
Abstract
Malignant neoplasms exhibit a higher rate of glycolysis than normal cells; this is known as the Warburg effect. To target it, a galactose-conjugated (trans-R,R-cyclohexane-1,2-diamine)-2-chloromalonato-platinum(II) complex (Gal-Pt) was designed, synthesized, and evaluated in five human cancer cell lines and against two different xenograft tumour models. Gal-Pt exhibits much higher aqueous solubility (over 25 times) and improved cytotoxicity than oxaliplatin, especially in human colon (HT29) and lung (H460) cancer cell lines. The safety profile of Gal-Pt was investigated in vivo by exploring the maximum tolerated dose (MTD) and animal mortality rate. The ratios of the animal lethal dosage values to the cytotoxicity in HT29 (LD50/IC50) showed that Gal-Pt was associated with an increased therapeutic index by over 30-fold compared to cisplatin and oxaliplatin. We evaluated in vivo antitumor activity by single agent intravenous treatment comparison studies of Gal-Pt (50 mg/kg as 65% MTD) and cisplatin (3 mg/kg, as 80% MTD) in a H460 lung cancer xenograft model, and with oxaliplatin (7 mg/kg, as 90% MTD) in a HT29 colon cancer xenograft model. The results show that Gal-Pt was more efficacious against H460 than cisplatin, and had superior potency in HT29 cells compared to oxaliplatin under nontoxic dosage conditions. The dependency between cytotoxicity of Gal-Pt and glucose transporters (GLUTs) was investigated by using quercetin as an inhibitor of GLUTs in HT29 cells. The cytotoxic potency of Gal-Pt was highly reduced by the inhibitor, suggesting that the uptake of Gal-Pt was regulated by glucose transporters. The GLUT mediated transportability and cellular uptake of Gal-Pt was also demonstrated using a fluorescent glucose bioprobe in HT29 competition assay.
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20
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Sage JM, Cura AJ, Lloyd KP, Carruthers A. Caffeine inhibits glucose transport by binding at the GLUT1 nucleotide-binding site. Am J Physiol Cell Physiol 2015; 308:C827-34. [PMID: 25715702 DOI: 10.1152/ajpcell.00001.2015] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 02/23/2015] [Indexed: 11/22/2022]
Abstract
Glucose transporter 1 (GLUT1) is the primary glucose transport protein of the cardiovascular system and astroglia. A recent study proposes that caffeine uncompetitive inhibition of GLUT1 results from interactions at an exofacial GLUT1 site. Intracellular ATP is also an uncompetitive GLUT1 inhibitor and shares structural similarities with caffeine, suggesting that caffeine acts at the previously characterized endofacial GLUT1 nucleotide-binding site. We tested this by confirming that caffeine uncompetitively inhibits GLUT1-mediated 3-O-methylglucose uptake in human erythrocytes [Vmax and Km for transport are reduced fourfold; Ki(app) = 3.5 mM caffeine]. ATP and AMP antagonize caffeine inhibition of 3-O-methylglucose uptake in erythrocyte ghosts by increasing Ki(app) for caffeine inhibition of transport from 0.9 ± 0.3 mM in the absence of intracellular nucleotides to 2.6 ± 0.6 and 2.4 ± 0.5 mM in the presence of 5 mM intracellular ATP or AMP, respectively. Extracellular ATP has no effect on sugar uptake or its inhibition by caffeine. Caffeine and ATP displace the fluorescent ATP derivative, trinitrophenyl-ATP, from the GLUT1 nucleotide-binding site, but d-glucose and the transport inhibitor cytochalasin B do not. Caffeine, but not ATP, inhibits cytochalasin B binding to GLUT1. Like ATP, caffeine renders the GLUT1 carboxy-terminus less accessible to peptide-directed antibodies, but cytochalasin B and d-glucose do not. These results suggest that the caffeine-binding site bridges two nonoverlapping GLUT1 endofacial sites-the regulatory, nucleotide-binding site and the cytochalasin B-binding site. Caffeine binding to GLUT1 mimics the action of ATP but not cytochalasin B on sugar transport. Molecular docking studies support this hypothesis.
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Affiliation(s)
- Jay M Sage
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts; and
| | - Anthony J Cura
- Diabetes Center For Excellence, University of Massachusetts Medical School, Worcester, Massachusetts
| | - Kenneth P Lloyd
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts; and
| | - Anthony Carruthers
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, Massachusetts; and
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21
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Gao F, Li M, Liu WB, Zhou ZS, Zhang R, Li JL, Zhou KC. Epigallocatechin gallate inhibits human tongue carcinoma cells via HK2‑mediated glycolysis. Oncol Rep 2015; 33:1533-9. [PMID: 25591943 DOI: 10.3892/or.2015.3727] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Accepted: 12/04/2014] [Indexed: 11/05/2022] Open
Abstract
Epigallocatechin gallate (EGCG), one of the major catechins found in green tea, was suggested to play a role as a chemopreventive agent in various human cancer models. In this study, we reported that EGCG has a profound antitumor effect on human tongue carcinoma cells by directly regulating glycolysis. EGCG dose-dependently inhibited anchorage-independent growth and short-term EGCG exposure substantially decreased EGF-induced EGF receptor (EGFR), Akt and ERK1/2 activation, as well as the downregulation of hexokinase 2 (HK2). Furthermore, inhibition of EGCG‑mediated HK2 expression was involved in Akt, but not in ERK1/2 signaling pathway suppression. Overexpression of constitutively activated Akt1 rescued inhibition of EGCG‑induced glycolysis. Moreover, EGCG inhibited HK2 expression on mitochondrial outer membrane and induced apoptosis. In summary, the results suggested that EGCG or a related analogue, may have a role in the management of human tongue carcinoma.
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Affiliation(s)
- Feng Gao
- Powder Metallurgy Research Institute of Central South University, Changsha, Hunan, P.R. China
| | - Ming Li
- Changsha Stomatological Hospital, Changsha, Hunan, P.R. China
| | - Wen-Bin Liu
- Department of Pathology, The Affiliated Cancer Hospital of Xiangya School of Medicine, Central South University, Hunan Cancer Hospital, Changsha, Hunan, P.R. China
| | - Zhong-Su Zhou
- Changsha Stomatological Hospital, Changsha, Hunan, P.R. China
| | - Rui Zhang
- Changsha Stomatological Hospital, Changsha, Hunan, P.R. China
| | - Jun-Ling Li
- Department of Ultrasonography, The Third Xiangya Hospital of Central South University, Changsha, Hunan, P.R. China
| | - Ke-Chao Zhou
- Powder Metallurgy Research Institute of Central South University, Changsha, Hunan, P.R. China
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22
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Legendre A, Jacques S, Dumont F, Cotton J, Paullier P, Fleury MJ, Leclerc E. Investigation of the hepatotoxicity of flutamide: Pro-survival/apoptotic and necrotic switch in primary rat hepatocytes characterized by metabolic and transcriptomic profiles in microfluidic liver biochips. Toxicol In Vitro 2014; 28:1075-87. [DOI: 10.1016/j.tiv.2014.04.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 04/03/2014] [Accepted: 04/09/2014] [Indexed: 02/08/2023]
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23
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Abstract
Caenorhabditis elegans is widely used as a model for investigation of the relationships between aging, nutrient restriction and signalling via the DAF-2 (abnormal dauer formation 2) receptor for insulin-like peptides and AGE-1 [ageing alteration 1; orthologue of PI3K (phosphoinositide 3-kinase)], but the identity of the glucose transporters that may link these processes is unknown. We unexpectedly find that of the eight putative GLUT (glucose transporter)-like genes only the two splice variants of one gene have a glucose transport function in an oocyte expression system. We have named this gene fgt-1 (facilitated glucose transporter, isoform 1). We show that knockdown of fgt-1 RNA leads to loss of glucose transport and reduced glucose metabolism in wild-type worms. The FGT-1 glucose transporters of C. elegans thus play a key role in glucose energy supply to C. elegans. Importantly, knockdown of fgt-1 leads to an extension of lifespan equivalent, but not additive, to that observed in daf-2 and age-1 mutant worms. The results of the present study are consistent with DAF-2 and AGE-1 signalling stimulating glucose transport in C. elegans and this process being associated with the longevity phenotype in daf-2 and age-1 mutant worms. We propose that fgt-1 constitutes a common axis for the lifespan extending effects of nutrient restriction and reduced insulin-like peptide signalling.
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24
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Park JH, Bae JH, Im SS, Song DK. Green tea and type 2 diabetes. Integr Med Res 2013; 3:4-10. [PMID: 28664072 PMCID: PMC5481694 DOI: 10.1016/j.imr.2013.12.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2013] [Revised: 12/02/2013] [Accepted: 12/06/2013] [Indexed: 12/27/2022] Open
Abstract
Green tea and coffee consumption have been widely popular worldwide. These beverages contain caffeine to activate the central nervous system by adenosine receptor blockade, and due to the caffeine, addiction or tolerance may occur. In addition to this caffeine effect, green tea and coffee consumption have always been at the center of discussions about human health, disease, and longevity. In particular, green tea catechins are involved in many biological activities such as antioxidation and modulation of various cellular lipid and proteins. Thus, they are beneficial against degenerative diseases, including obesity, cancer, cardiovascular diseases, and various inflammatory diseases. Some reports also suggest that daily consumption of tea catechins may help in controlling type 2 diabetes. However, other studies have reported that chronic consumption of green tea may result in hepatic failure, neuronal damage, and exacerbation of diabetes, suggesting that interindividual variations in the green tea effect are large. This review will focus on the effect of green tea catechins extracted from the Camellia sinensis plant on type 2 diabetes and obesity, and the possible mechanistic explanation for the experimental results mainly from our laboratory. It is hoped that green tea can be consumed in a suitable manner as a supplement to prevent the development of type 2 diabetes and obesity.
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Affiliation(s)
- Jae-Hyung Park
- Department of Physiology, Keimyung University School of Medicine, Daegu, Korea
| | - Jae-Hoon Bae
- Department of Physiology, Keimyung University School of Medicine, Daegu, Korea
| | - Sung-Soon Im
- Department of Physiology, Keimyung University School of Medicine, Daegu, Korea
| | - Dae-Kyu Song
- Department of Physiology, Keimyung University School of Medicine, Daegu, Korea
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25
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Bae KC, Park JH, Na AY, Kim SJ, Ahn S, Kim SP, Oh BC, Cho HC, Kim YW, Song DK. Effect of Green Tea Extract/Poly-γ-Glutamic Acid Complex in Obese Type 2 Diabetic Mice. Diabetes Metab J 2013; 37:196-206. [PMID: 23807923 PMCID: PMC3689017 DOI: 10.4093/dmj.2013.37.3.196] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 03/05/2013] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND The increasing prevalence of type 2 diabetes mellitus (T2DM) is associated with the rapid spread of obesity. Obesity induces insulin resistance, resulting in β-cell dysfunction and thus T2DM. Green tea extract (GTE) has been known to prevent obesity and T2DM, but this effect is still being debated. Our previous results suggested that circulating green tea gallated catechins (GCs) hinders postprandial blood glucose lowering, regardless of reducing glucose and cholesterol absorption when GCs are present in the intestinal lumen. This study aimed to compare the effect of GTE with that of GTE coadministered with poly-γ-glutamic acid (γ-PGA), which is likely to inhibit the intestinal absorption of GCs. METHODS The db/db mice and age-matched nondiabetic mice were provided with normal chow diet containing GTE (1%), γ-PGA (0.1%), or GTE+γ-PGA (1%:0.1%) for 4 weeks. RESULTS In nondiabetic mice, none of the drugs showed any effects after 4 weeks. In db/db mice, however, weight gain and body fat gain were significantly reduced in the GTE+γ-PGA group compared to nondrug-treated db/db control mice without the corresponding changes in food intake and appetite. Glucose intolerance was also ameliorated in the GTE+γ-PGA group. Histopathological analyses showed that GTE+γ-PGA-treated db/db mice had a significantly reduced incidence of fatty liver and decreased pancreatic islet size. Neither GTE nor γ-PGA treatment showed any significant results. CONCLUSION These results suggest that GTE+γ-PGA treatment than GTE or γ-PGA alone may be a useful tool for preventing both obesity and obesity-induced T2DM.
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Affiliation(s)
- Ki-Cheor Bae
- Department of Physiology, Keimyung University School of Medicine, Daegu, Korea
| | - Jae-Hyung Park
- Department of Physiology, Keimyung University School of Medicine, Daegu, Korea
| | - Ann-Yae Na
- Department of Physiology, Keimyung University School of Medicine, Daegu, Korea
| | - Sun-Joo Kim
- Department of Physiology, Keimyung University School of Medicine, Daegu, Korea
| | | | - Sang-Pyo Kim
- Department of Pathology, Keimyung University School of Medicine, Daegu, Korea
| | - Byung-Chul Oh
- Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, Korea
| | - Ho-Chan Cho
- Department of Internal Medicine, Keimyung University School of Medicine, Daegu, Korea
| | - Yong Woon Kim
- Department of Physiology, Yeungnam University College of Medicine, Daegu, Korea
| | - Dae-Kyu Song
- Department of Physiology, Keimyung University School of Medicine, Daegu, Korea
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26
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Park JH, Choi YJ, Kim YW, Kim SP, Cho HC, Ahn S, Bae KC, Im SS, Bae JH, Song DK. Green tea extract with polyethylene glycol-3350 reduces body weight and improves glucose tolerance in db/db and high-fat diet mice. Naunyn Schmiedebergs Arch Pharmacol 2013; 386:733-45. [PMID: 23620335 DOI: 10.1007/s00210-013-0869-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2012] [Accepted: 04/02/2013] [Indexed: 02/08/2023]
Abstract
Green tea extract (GTE) is regarded to be effective against obesity and type 2 diabetes, but definitive evidences have not been proven. Based on the assumption that the gallated catechins (GCs) in GTE attenuate intestinal glucose and lipid absorption, while enhancing insulin resistance when GCs are present in the circulation through inhibiting cellular glucose uptake in various tissues, this study attempted to block the intestinal absorption of GCs and prolong their residence time in the lumen. We then observed whether GTE containing the nonabsorbable GCs could ameliorate body weight (BW) gain and glucose intolerance in db/db and high-fat diet mice. Inhibition of the intestinal absorption of GCs was accomplished by co-administering the nontoxic polymer polyethylene glycol-3350 (PEG). C57BLKS/J db/db and high-fat diet C57BL/6 mice were treated for 4 weeks with drugs as follows: GTE, PEG, GTE+PEG, voglibose, or pioglitazone. GTE mixed with meals did not have any ameliorating effects on BW gain and glucose intolerance. However, the administration of GTE plus PEG significantly reduced BW gain, insulin resistance, and glucose intolerance, without affecting food intake and appetite. The effect was comparable to the effects of an α-glucosidase inhibitor and a peroxisome proliferator-activated receptor-γ/α agonist. These results indicate that prolonging the action of GCs of GTE in the intestinal lumen and blocking their entry into the circulation may allow GTE to be used as a prevention and treatment for both obesity and obesity-induced type 2 diabetes.
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Affiliation(s)
- Jae-Hyung Park
- Department of Physiology and Endocrinology, Keimyung University School of Medicine, 1095 Dalgubeoldae-Ro, Dalseo-Gu, Daegu, 704-701, South Korea
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Tagashira T, Choshi T, Hibino S, Kamishikiryou J, Sugihara N. Influence of Gallate and Pyrogallol Moieties on the Intestinal Absorption of (−)-Epicatechin and (−)-Epicatechin Gallate. J Food Sci 2012; 77:H208-15. [DOI: 10.1111/j.1750-3841.2012.02902.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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28
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Choucha Snouber L, Bunescu A, Naudot M, Legallais C, Brochot C, Dumas ME, Elena-Herrmann B, Leclerc E. Metabolomics-on-a-chip of hepatotoxicity induced by anticancer drug flutamide and Its active metabolite hydroxyflutamide using HepG2/C3a microfluidic biochips. Toxicol Sci 2012; 132:8-20. [PMID: 22843567 DOI: 10.1093/toxsci/kfs230] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We used the recently introduced "metabolomics-on-a-chip" approach to test secondary drug toxicity in bioartificial organs. Bioartificial organs cultivated in microfluidic culture conditions provide a beneficial environment, in which the cellular cytoprotective mechanisms are enhanced, compared with Petri dish culture conditions. We investigated the metabolic response of HepG2/C3a cells exposed to flutamide, an anticancer prodrug, and hydroxyflutamide (HF), its active metabolite, in a microfluidic biochip. The cellular response was analyzed by (1)H nuclear magnetic resonance spectroscopy to identify cell-specific molecule-response markers. The metabolic response to flutamide results in a disruption of glucose homeostasis and in mitochondrial dysfunctions. This flutamide-specific metabolic response was illustrated by a reduction of the extracellular glucose and fructose consumptions and a general reduction of the tricarboxylic acid cycle activity leading to the reduction of the consumption of several amino acids. We also found a higher production of 3-hydroxybutyrate and lactate, and the reduction of the albumin production compared with controls. The toxic metabolic signature associated with the active metabolite HF was illustrated by a high-energy demand and an increase in several amino acid metabolism. Finally, for both molecules, the hepatotoxicity was correlated to the glutathione (GSH) metabolism illustrated by the levels of the 2-hydroxybutyrate and pyroglutamate productions and the increase of the glutamate and glycine productions. Thus, the entire set of results contributed to extract specific mechanistic toxic signatures and their relation to hepatotoxicity, which appeared consistent with literature reports. As new finding of HepG2/C3a cells hepatotoxicity, we propose a metabolic network with a related list of metabolite variations to describe the GSH depletion when followed by a cell death for the HepG2/C3a cells cultivated in our polydimethylsiloxane microfluidic biochips. Our findings illustrate the potential of metabolomics-on-a-chip as an in vitro alternative method for predictive toxicology.
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Affiliation(s)
- Leila Choucha Snouber
- Université de Technologie de Compiègne, Centre de Recherche de Royallieu, Compiègne Cedex, France
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29
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The ability of gallate and pyrogallol moieties of catechins to inhibit P-glycoprotein function. J Funct Foods 2011. [DOI: 10.1016/j.jff.2011.05.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
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30
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Slavic K, Krishna S, Derbyshire ET, Staines HM. Plasmodial sugar transporters as anti-malarial drug targets and comparisons with other protozoa. Malar J 2011; 10:165. [PMID: 21676209 PMCID: PMC3135577 DOI: 10.1186/1475-2875-10-165] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2011] [Accepted: 06/15/2011] [Indexed: 01/28/2023] Open
Abstract
Glucose is the primary source of energy and a key substrate for most cells. Inhibition of cellular glucose uptake (the first step in its utilization) has, therefore, received attention as a potential therapeutic strategy to treat various unrelated diseases including malaria and cancers. For malaria, blood forms of parasites rely almost entirely on glycolysis for energy production and, without energy stores, they are dependent on the constant uptake of glucose. Plasmodium falciparum is the most dangerous human malarial parasite and its hexose transporter has been identified as being the major glucose transporter. In this review, recent progress regarding the validation and development of the P. falciparum hexose transporter as a drug target is described, highlighting the importance of robust target validation through both chemical and genetic methods. Therapeutic targeting potential of hexose transporters of other protozoan pathogens is also reviewed and discussed.
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Affiliation(s)
- Ksenija Slavic
- Centre for Infection, Division of Cellular and Molecular Medicine, St. George's, University of London, Cranmer Terrace, London SW17 0RE, UK.
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Vlachodimitropoulou E, Sharp PA, Naftalin RJ. Quercetin-iron chelates are transported via glucose transporters. Free Radic Biol Med 2011; 50:934-44. [PMID: 21238582 DOI: 10.1016/j.freeradbiomed.2011.01.005] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Revised: 12/31/2010] [Accepted: 01/06/2011] [Indexed: 10/18/2022]
Abstract
Flavonoids are well-known antioxidants and free radical scavengers. Their metal-binding activity suggests that they could be effective protective agents in pathological conditions caused by both extracellular and intracellular oxidative stress linked to metal overload. Quercetin is both a permeant ligand via glucose transport proteins (GLUTs) and a high-affinity inhibitor of GLUT-mediated glucose transport. Chelatable "free iron" at micromolar concentrations in body fluids is a catalyst of hydroxyl radical (OH(•)) production from hydrogen peroxide. A number of flavonoids, e.g., quercetin, luteolin, chrysin, and 3,6-dihydroxyflavone, have been demonstrated to chelate intracellular iron and suppress OH(•) radical production in Madin Darby canine kidney cells. The most effective chelation comes from the flavonone B ring catechol found in both quercetin and luteolin. We show here that quercetin concentrations of <1μM can facilitate chelatable iron shuttling via GLUT1 in either direction across the cell membrane. These siderophoric effects are inhibited by raised quercetin concentrations (>1μM) or GLUT inhibitors, e.g., phloretin or cytochalasin B, and iron efflux is enhanced by impermeant extracellular iron chelators, either desferrioxamine or rutin. This iron shuttling property of quercetin might be usefully harnessed in chelotherapy of iron-overload conditions.
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Robichaud T, Appleyard AN, Herbert RB, Henderson PJF, Carruthers A. Determinants of ligand binding affinity and cooperativity at the GLUT1 endofacial site. Biochemistry 2011; 50:3137-48. [PMID: 21384913 DOI: 10.1021/bi1020327] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Cytochalasin B (CB) and forskolin (FSK) inhibit GLUT1-mediated sugar transport in red cells by binding at or close to the GLUT1 endofacial sugar binding site. Paradoxically, very low concentrations of each of these inhibitors produce a modest stimulation of sugar transport [ Cloherty, E. K., Levine, K. B., and Carruthers, A. ((2001)) The red blood cell glucose transporter presents multiple, nucleotide-sensitive sugar exit sites. Biochemistry 40 ((51)) 15549-15561]. This result is consistent with the hypothesis that the glucose transporter contains multiple, interacting, endofacial binding sites for CB and FSK. The present study tests this hypothesis directly and, by screening a library of cytochalasin and forskolin analogues, asks what structural features of endofacial site ligands determine binding site affinity and cooperativity. Like CB, FSK competitively inhibits exchange 3-O-methylglucose transport (sugar uptake in cells containing intracellular sugar) but noncompetitively inhibits sugar uptake into cells lacking sugar at 4 °C. This refutes the hypothesis that FSK binds at GLUT1 endofacial and exofacial sugar binding sites. Some forskolin derivatives and cytochalasins inhibit equilibrium [(3)H]-CB binding to red cell membranes depleted of peripheral proteins at 4 °C. Others produce a moderate stimulation of [(3)H]-CB binding when introduced at low concentrations but inhibit binding as their concentration is increased. Yet other analogues modestly stimulate [(3)H]-CB binding at all inhibitor concentrations applied. These findings are explained by a carrier that presents at least two interacting endofacial binding sites for CB or FSK. We discuss this result within the context of models for GLUT1-mediated sugar transport and GLUT1 quaternary structure, and we evaluate the major determinants of ligand binding affinity and cooperativity.
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Affiliation(s)
- Trista Robichaud
- Department of Biochemistry & Molecular Pharmacology, University of Massachusetts Medical School, 364 Plantation Street Worcester, Massachusetts 01605, United States
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Siddiqui IA, Asim M, Hafeez BB, Adhami VM, Tarapore RS, Mukhtar H. Green tea polyphenol EGCG blunts androgen receptor function in prostate cancer. FASEB J 2010; 25:1198-207. [PMID: 21177307 DOI: 10.1096/fj.10-167924] [Citation(s) in RCA: 153] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Androgen deprivation therapy is the major treatment for advanced prostate cancer (PCa). However, it is a temporary remission, and the patients almost inevitably develop hormone refractory prostate cancer (HRPC). HRPC is almost incurable, although most HRPC cells still express androgen receptor (AR) and depend on the AR for growth, making AR a prime drug target. Here, we provide evidence that epigallocatechin-3-gallate (EGCG), the major polyphenol in green tea, is a direct antagonist of androgen action. In silico modeling and FRET-based competition assay showed that EGCG physically interacts with the ligand-binding domain of AR by replacing a high-affinity labeled ligand (IC(50) 0.4 μM). The functional consequence of this interaction was a decrease in AR-mediated transcriptional activation, which was due to EGCG mediated inhibition of interdomain N-C termini interaction of AR. Treatment with EGCG also repressed the transcriptional activation by a hotspot mutant AR (T877A) expressed ectopically as well as the endogenous AR mutant. As the physiological consequence of AR antagonism, EGCG repressed R1881-induced PCa cell growth. In a xenograft model, EGCG was found to inhibit AR nuclear translocation and protein expression. We also observed a significant down-regulation of androgen-regulated miRNA-21 and up-regulation of a tumor suppressor, miRNA-330, in tumors of mice treated with EGCG. Taken together, we provide evidence that EGCG functionally antagonizes androgen action at multiple levels, resulting in inhibition of PCa growth.
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Affiliation(s)
- Imtiaz A Siddiqui
- Department of Dermatology, University of Wisconsin, Madison, Wisconsin 53706, USA
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Levy R, Khokhlov A, Kopenkin S, Bart B, Ermolova T, Kantemirova R, Mazurov V, Bell M, Caldron P, Pillai L, Burnett B. Efficacy and safety of flavocoxid compared with naproxen in subjects with osteoarthritis of the knee- a subset analysis. Adv Ther 2010; 27:953-62. [PMID: 20972845 DOI: 10.1007/s12325-010-0083-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Indexed: 12/20/2022]
Abstract
OBJECTIVE twice-daily flavocoxid, a cyclooxygenase and 5-lipoxygenase inhibitor with potent antioxidant activity of botanical origin, was evaluated for 12 weeks in a randomized, double-blind, active-comparator study against naproxen in 220 subjects with moderate-severe osteoarthritis (OA) of the knee. As previously reported, both groups noted a significant reduction in the signs and symptoms of OA with no detectable differences in efficacy between the groups when the entire intent-to-treat population was considered. This post-hoc analysis compares the efficacy of flavocoxid to naproxen in different subsets of patients, specifically those related to age, gender, and disease severity as reported at baseline for individual response parameters. METHODS in the original randomized, double-blind study, 220 subjects were assigned to receive either flavocoxid (500 mg twice daily) or naproxen (500 mg twice daily) for 12 weeks. In this subgroup analysis, primary outcome measures including the Western Ontario and McMaster Universities OA index and subscales, timed walk, and secondary efficacy variables, including investigator global assessment for disease and global response to treatment, subject visual analog scale for discomfort, overall disease activity, global response to treatment, index joint tenderness and mobility, were evaluated for differing trends between the study groups. RESULTS subset analyses revealed some statistically significant differences and some notable trends in favor of the flavocoxid group. These trends became stronger the longer the subjects continued on therapy. These observations were specifically noted in older subjects (>60 years), males and in subjects with milder disease, particularly those with lower subject global assessment of disease activity and investigator global assessment for disease and faster walking times at baseline. CONCLUSIONS initial analysis of the entire intent-to-treat population revealed that flavocoxid was as effective as naproxen in managing the signs and symptoms of OA of the knee. Detailed analyses of subject subsets demonstrated distinct trends in favor of flavocoxid for specific groups of subjects.
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Affiliation(s)
- Robert Levy
- Primus Pharmaceuticals, 4725 N. Scottsdale Road, Scottsdale, AZ 85251, USA.
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Levy RM, Khokhlov A, Kopenkin S, Bart B, Ermolova T, Kantemirova R, Mazurov V, Bell M, Caldron P, Pillai L, Burnett BP. Efficacy and safety of flavocoxid, a novel therapeutic, compared with naproxen: a randomized multicenter controlled trial in subjects with osteoarthritis of the knee. Adv Ther 2010; 27:731-42. [PMID: 20845002 DOI: 10.1007/s12325-010-0064-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Indexed: 12/18/2022]
Abstract
INTRODUCTION Flavocoxid is a novel flavonoid-based "dual inhibitor" of the 5-lipoxygenase (5-LOX) enzyme and the cyclooxygenase (COX) enzymes. This study was designed to compare the effectiveness and safety of flavocoxid to naproxen in subjects with moderate to severe osteoarthritis (OA) of the knee. METHODS In this randomized, multicenter, double-blind study, 220 subjects were assigned to receive either flavocoxid (500 mg twice daily) or naproxen (500 mg twice daily) for 12 weeks. The trial was structured to show noninferiority of flavocoxid to naproxen. Primary outcome measures included the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and subscales and a timed walk. RESULTS More than 90% of the subjects in both groups noted significant reduction in the signs and symptoms of knee OA. There were no statistically significant differences in efficacy between the flavocoxid and naproxen groups when the entire intent-to-treat population was analyzed. The flavocoxid group had significantly fewer upper gastrointestinal (UGI) and renal (edema) adverse events (AEs) as well as a strong trend toward fewer respiratory AEs. CONCLUSION Flavocoxid, a first-in-class flavonoid-based therapeutic that inhibits COX-1 and COX-2 as well as 5-LOX, was as effective as naproxen in managing the signs and symptoms of OA of the knee. Flavocoxid demonstrated better UGI, renal (edema), and respiratory safety profiles than naproxen.
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Affiliation(s)
- Robert M Levy
- Primus Pharmaceuticals, Inc., Scottsdale, AZ 85251, USA.
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Role of (-)-epigallocatechin-3-gallate in cell viability, lipogenesis, and retinol-binding protein 4 expression in adipocytes. Naunyn Schmiedebergs Arch Pharmacol 2010; 382:303-10. [PMID: 20711765 DOI: 10.1007/s00210-010-0547-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Accepted: 07/31/2010] [Indexed: 10/19/2022]
Abstract
(-)-Epigallocatechin-3-gallate (EGCG), a bioactive compound of green tea, is known to combat obesity by reducing the viability and lipid accumulation of adipocytes. In this study, we evaluated the mechanism and clinical relevance on those actions of EGCG. We measured the viability of 3T3-L1 preadipocytes and adipocytes by the 3-(4, 5-dimethylthiazol-2yl)-2, 5-diphenyltetrazolium bromide assay. Lipid accumulation was measured by Oil Red O staining. Intracellular accumulation of reactive oxygen species (ROS) was determined using a flow cytometer. Cellular glucose uptake was determined with 2-deoxy-[(3)H]-glucose. The protein levels of peroxisome proliferator-activated receptor (PPAR)-γ and adiponectin in 3T3-L1 adipocytes, as well as the protein level and secretion of plasma retinol-binding protein (RBP4) in human adipocytes, were measured by western blot. EGCG at concentrations higher than 10 μM induced ROS generation and decreased the viability and lipid accumulation of adipocytes. It also decreased the expression of PPAR-γ and adiponectin. At concentrations readily achievable in human plasma via green tea intake (≤10 μM), EGCG inhibited cellular glucose uptake and enhanced the expression and secretion of RBP4 in adipocytes. Pharmacological doses of EGCG showed cytotoxic effects in preadipocytes and adipocytes. EGCG-mediated glucose uptake inhibition in adipocytes may be clinically relevant and is probably linked to the increase in the expression and secretion of RBP4. Because secreted RBP4 from adipocytes inhibits muscular glucose uptake and enhance hepatic glucose output, the systemic effect of EGCG associated with its effect on RBP4 secretion should be further determined, as it may negatively regulate whole-body insulin sensitivity, contrary to general belief.
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Amann T, Hellerbrand C. GLUT1 as a therapeutic target in hepatocellular carcinoma. Expert Opin Ther Targets 2010; 13:1411-27. [PMID: 19874261 DOI: 10.1517/14728220903307509] [Citation(s) in RCA: 149] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Primary hepatocellular carcinoma (HCC) is one of the most fatal cancers in humans with rising incidence in many regions around the world. Currently, no satisfactory curative pharmacological treatment is available, and the outcome is mostly poor. Recently, we have shown that the glucose transporter GLUT1 is increased in a subset of patients with HCC and functionally affects tumorigenicity. GLUT1 is a rate-limiting transporter for glucose uptake, and its expression correlates with anaerobic glycolysis. This phenomenon is also known as the Warburg effect and recently became of great interest, since it affects not only glucose uptake and utilization but also has an influence on tumorigenic features like metastasis, chemoresistance and escape from immune surveillance. Consistent with this, RNA-interference-mediated inhibition of GLUT1 expression in HCC cells resulted in reduced tumorigenicity. Together, these findings indicate that GLUT1 is a novel and attractive therapeutic target for HCC. This review summarizes our current knowledge on the expression and function of GLUT1 in HCC, available drugs/strategies to inhibit GLUT1 expression or function, and potential side effects of such therapeutic strategies.
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Affiliation(s)
- Thomas Amann
- University Hospital Regensburg, Department of Internal Medicine I, D-93042 Regensburg, Germany
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Slavic K, Derbyshire ET, Naftalin RJ, Krishna S, Staines HM. Comparison of effects of green tea catechins on apicomplexan hexose transporters and mammalian orthologues. Mol Biochem Parasitol 2009; 168:113-6. [PMID: 19577593 PMCID: PMC2791876 DOI: 10.1016/j.molbiopara.2009.06.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2009] [Revised: 05/17/2009] [Accepted: 06/25/2009] [Indexed: 12/01/2022]
Abstract
Here we have investigated the inhibitory properties of green tea catechins on the Plasmodium falciparum hexose transporter (PfHT), the Babesia bovis hexose transporter 1 (BboHT1) and the mammalian facilitative glucose transporters, GLUT1 and GLUT5, expressed in Xenopus laevis oocytes. (-)-Epicatechin-gallate (ECG) and (-)-epigallocatechin-gallate (EGCG) inhibited D-glucose transport by GLUT1 and PfHT, and D-fructose transport by GLUT5, with apparent K(i) values between 45 and 117 microM. BboHT1 was more potently inhibited by the ungallated catechins (-)-epicatechin (EC) and (-)-epigallocatechin (EGC), with apparent K(i) values of 108 and 168 microM, respectively. Site-directed mutagenesis experiments provided little further support for previously reported models of catechin binding to hexose transporters. Furthermore, P. falciparum growth inhibition by catechins was not affected by the external D-glucose concentration. Our results provide new data on the inhibitory action of catechins against sugar transporters but were unable to elucidate the antimalarial mechanism of action of these agents.
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Affiliation(s)
- Ksenija Slavic
- Centre for Infection, Division of Cellular and Molecular Medicine, St. George's, University of London, Cranmer Terrace, London SW17 0RE, UK
| | - Elvira T. Derbyshire
- Centre for Infection, Division of Cellular and Molecular Medicine, St. George's, University of London, Cranmer Terrace, London SW17 0RE, UK
| | - Richard J. Naftalin
- Physiology, Franklin Wilkins Building, King's College London, Waterloo Campus, London SE1 9HN, UK
| | - Sanjeev Krishna
- Centre for Infection, Division of Cellular and Molecular Medicine, St. George's, University of London, Cranmer Terrace, London SW17 0RE, UK
| | - Henry M. Staines
- Centre for Infection, Division of Cellular and Molecular Medicine, St. George's, University of London, Cranmer Terrace, London SW17 0RE, UK
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Peroxynitrite signaling in human erythrocytes: Synergistic role of hemoglobin oxidation and band 3 tyrosine phosphorylation. Arch Biochem Biophys 2009; 484:173-82. [DOI: 10.1016/j.abb.2008.10.025] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2008] [Revised: 10/16/2008] [Accepted: 10/20/2008] [Indexed: 11/18/2022]
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Kuzuhara T, Suganuma M, Fujiki H. Green tea catechin as a chemical chaperone in cancer prevention. Cancer Lett 2008; 261:12-20. [PMID: 18068893 DOI: 10.1016/j.canlet.2007.10.037] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2007] [Accepted: 10/30/2007] [Indexed: 11/18/2022]
Abstract
Green tea catechins have recently gained significant acceptance as a cancer preventive, and one of the important features of catechins is their interactions with various target molecules. We recently found a functional and structural similarity between catechins and chaperones: Stochastic conformational analysis in silico revealed numerous conformations of (-)-epigallocatechin gallate, (-)-epicatechin gallate and (-)-epigallocatechin, showing a unique flexibility and mobility of the catechin molecules and suggesting the significance of a galloyl group in conformational variation. Since these conformations result in interaction with various types of molecules, we think that green tea catechin induces cancer preventive activity mediated through a chaperone-like property.
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Affiliation(s)
- Takashi Kuzuhara
- Laboratory of Biochemistry, Faculty of Pharmaceutical Sciences, Tokushima Bunri University, Yamashiro-cho, Tokushima 770-8514, Japan.
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41
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Araujo JR, Goncalves P, Martel F. Modulation of Glucose Uptake in a Human Choriocarcinoma Cell Line (BeWo) by Dietary Bioactive Compounds and Drugs of Abuse. J Biochem 2008; 144:177-86. [DOI: 10.1093/jb/mvn054] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
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Abstract
PURPOSE OF REVIEW The burden of androgen deficiency in men with diabetes and the metabolic syndrome has become increasingly apparent in population-based studies. This article focuses on the mechanisms underlying the interdependent relationship between these conditions. RECENT FINDINGS Various definitions of hypogonadism, the metabolic syndrome and diabetes have been proposed and are used in the literature. Cross-sectional studies have found that between 20 and 64% of men with diabetes have hypogonadism, with higher prevalence rates found in the elderly. Hypogonadism can be a risk factor for the development of diabetes and the metabolic syndrome through various mechanisms including changes in body composition; androgen receptor polymorphisms; glucose transport; and reduced antioxidant effect. Conversely, diabetes and the metabolic syndrome can be risk factors for hypogonadism through some similar but mostly distinct mechanisms, such as increased body weight; decreased sex hormone binding globulin levels; suppression of gonadotrophin release or Leydig cell testosterone production; cytokine-mediated inhibition of testicular steroid production; and increased aromatase activity contributing to relative estrogen excess. SUMMARY The relationship between diabetes, the metabolic syndrome and androgen deficiency is complex. Testosterone supplementation, by either oral or intramuscular routes and through exogenous or endogenous delivery, has a promising role in this population although further clinical trials are needed.
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Affiliation(s)
- Rita R Kalyani
- Division of Endocrinology and Metabolism, Johns Hopkins School of Medicine, Baltimore, Maryland 21287, USA
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Cunningham P, Afzal-Ahmed I, Naftalin RJ. Docking studies show that D-glucose and quercetin slide through the transporter GLUT1. J Biol Chem 2005; 281:5797-803. [PMID: 16407180 DOI: 10.1074/jbc.m509422200] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
On a three-dimensional templated model of GLUT1 (Protein Data Bank code 1SUK), a molecular recognition program, AUTODOCK 3, reveals nine hexose-binding clusters spanning the entire "hydrophilic" channel. Five of these cluster sites are within 3-5 A of 10 glucose transporter deficiency syndrome missense mutations. Another three sites are within 8 A of two other missense mutations. D-glucose binds to five sites in the external channel opening, with increasing affinity toward the pore center and then passes via a narrow channel into an internal vestibule containing four lower affinity sites. An external site, not adjacent to any mutation, also binding phloretin but recognizing neither D-fructose nor L-glucose, may be the main threading site for glucose uptake. Glucose exit from human erythrocytes is inhibited by quercetin (K(i) = 2.4 mum) but not anionic quercetin-semiquinone. Quercetin influx is retarded by extracellular D-glucose (50 mm) but not by phloretin and accelerated by intracellular D-glucose. Quercetin docking sites are absent from the external opening but fill the entire pore center. In the inner vestibule, Glu(254) and Lys(256) hydrogen-bond quercetin (K(i) approximately 10 microm) but not quercetin-semiquinone. Consistent with the kinetics, this site also binds D-glucose, so quercetin displacement by glucose could accelerate quercetin influx, whereas quercetin binding here will competitively inhibit glucose efflux. Beta-D-hexoses dock twice as frequently as their alpha-anomers to the 23 aromatic residues in the transport pathway, suggesting that endocyclic hexose hydrogens, as with maltosaccharides in maltoporins, form pi-bonds with aromatic rings and slide between sites instead of being translocated via a single alternating site.
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Affiliation(s)
- Philip Cunningham
- Bioinformatics, Franklin-Wilkins Building, King's College London, London SE1 9NH, United Kingdom
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Strobel P, Allard C, Perez-Acle T, Calderon R, Aldunate R, Leighton F. Myricetin, quercetin and catechin-gallate inhibit glucose uptake in isolated rat adipocytes. Biochem J 2005; 386:471-8. [PMID: 15469417 PMCID: PMC1134865 DOI: 10.1042/bj20040703] [Citation(s) in RCA: 151] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2004] [Revised: 09/27/2004] [Accepted: 10/07/2004] [Indexed: 12/15/2022]
Abstract
The facilitative glucose transporter, GLUT4, mediates insulin-stimulated glucose uptake in adipocytes and muscles, and the participation of GLUT4 in the pathogenesis of various clinical conditions associated with obesity, visceral fat accumulation and insulin resistance has been proposed. Glucose uptake by some members of the GLUT family, mainly GLUT1, is inhibited by flavonoids, the natural polyphenols present in fruits, vegetables and wine. Therefore it is of interest to establish if these polyphenolic compounds present in the diet, known to be effective antioxidants but also endowed with several other biological activities such as protein-tyrosine kinase inhibition, interfere with GLUT4 function. In the present study, we show that three flavonoids, quercetin, myricetin and catechin-gallate, inhibit the uptake of methylglucose by adipocytes over the concentration range of 10-100 microM. These three flavonoids show a competitive pattern of inhibition, with K(i)=16, 33.5 and 90 microM respectively. In contrast, neither catechin nor gallic acid inhibit methylglucose uptake. To obtain a better understanding of the interaction among GLUT4 and flavonoids, we have derived a GLUT4 three-dimensional molecular comparative model, using structural co-ordinates from a GLUT3 comparative model and a mechanosensitive ion channel [PDB (Protein Data Bank) code 1MSL] solved by X-ray diffraction. On the whole, the experimental evidence and computer simulation data favour a transport inhibition mechanism in which flavonoids and GLUT4 interact directly, rather than by a mechanism related to protein-tyrosine kinase and insulin signalling inhibition. Furthermore, the results suggest that GLUT transporters are involved in flavonoid incorporation into cells.
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Affiliation(s)
- Pablo Strobel
- Molecular Nutrition Laboratory, Faculty of Biological Sciences, Universidad Católica de Chile, Casilla 114-D, Santiago, Chile.
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Kitagawa S, Nabekura T, Kamiyama S. Inhibition of P-glycoprotein function by tea catechins in KB-C2 cells. J Pharm Pharmacol 2004; 56:1001-5. [PMID: 15285844 DOI: 10.1211/0022357044003] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
We studied the effects of tea catechins, (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECG), and (-)-epigallocatechin gallate (EGCG) on the P-glycoprotein (P-gp) function in multidrug-resistant P-gp over-expressing KB-C2 cells. EC did not have any effects on cellular accumulation of P-gp substrates, rhodamine-123 and daunorubicin, but the other catechins increased the accumulation in the order of EGC < ECG < EGCG. The effects of EGCG were larger than those of verapamil and quercetin. Since these catechins inhibited the efflux of P-gp substrates, the elevation of substrate accumulation seemed to be induced by the inhibition of the efflux transporter. The results showed that the inhibitory effects of the catechins did not depend on their total hydrophobicity, but significantly depended on their chemical structure. The presence of the galloyl moiety on the C-ring markedly increased the n-octanol/PBS partition coefficients of the catechins and their activity on P-gp. On the other hand, the presence of the trihydric pyrogallol group as the B-ring decreased the partition coefficients but increased the activity on P-gp, compared with the action of the corresponding catechins with a dihydric catechol B-ring.
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Affiliation(s)
- Shuji Kitagawa
- Niigata University of Pharmacy and Applied Life Sciences, Kamishin'ei-cho 5-13-2, 950-2081, Japan.
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Salas-Burgos A, Iserovich P, Zuniga F, Vera JC, Fischbarg J. Predicting the three-dimensional structure of the human facilitative glucose transporter glut1 by a novel evolutionary homology strategy: insights on the molecular mechanism of substrate migration, and binding sites for glucose and inhibitory molecules. Biophys J 2004; 87:2990-9. [PMID: 15326030 PMCID: PMC1304772 DOI: 10.1529/biophysj.104.047886] [Citation(s) in RCA: 147] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2004] [Accepted: 08/09/2004] [Indexed: 12/13/2022] Open
Abstract
The glucose transporters (GLUT/SLC2A) are members of the major facilitator superfamily. Here, we generated a three-dimensional model for Glut1 using a two-step strategy: 1), GlpT structure as an initial homology template and 2), evolutionary homology using glucose-6-phosphate translocase as a template. The resulting structure (PDB No. 1SUK) exhibits a water-filled passageway communicating the extracellular and intracellular domains, with a funnel-like exofacial vestibule (infundibulum), followed by a 15 A-long x 8 A-wide channel, and a horn-shaped endofacial vestibule. Most residues which, by mutagenesis, are crucial for transport delimit the channel, and putative sugar recognition motifs (QLS, QLG) border both ends of the channel. On the outside of the structure there are two positively charged cavities (one exofacial, one endofacial) delimited by ATP-binding Walker motifs, and an exofacial large side cavity of yet unknown function. Docking sites were found for the glucose substrate and its inhibitors: glucose, forskolin, and phloretin at the exofacial infundibulum; forskolin, and phloretin at an endofacial site next to the channel opening; and cytochalasin B at a positively charged endofacial pocket 3 A away from the channel. Thus, 1SUK accounts for practically all biochemical and mutagenesis evidence, and provides clues for the transport process.
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Affiliation(s)
- Alexis Salas-Burgos
- Department of Ophthalmology, College of Physicians & Surgeons, Columbia University, New York, New York 10032, USA
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Naftalin RJ, Cunningham P, Afzal-Ahmed I. Piracetam and TRH analogues antagonise inhibition by barbiturates, diazepam, melatonin and galanin of human erythrocyte D-glucose transport. Br J Pharmacol 2004; 142:594-608. [PMID: 15148255 PMCID: PMC1574967 DOI: 10.1038/sj.bjp.0705798] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
1 Nootropic drugs increase glucose uptake into anaesthetised brain and into Alzheimer's diseased brain. Thyrotropin-releasing hormone, TRH, which has a chemical structure similar to nootropics increases cerebellar uptake of glucose in murine rolling ataxia. This paper shows that nootropic drugs like piracetam (2-oxo 1 pyrrolidine acetamide) and levetiracetam and neuropeptides like TRH antagonise the inhibition of glucose transport by barbiturates, diazepam, melatonin and endogenous neuropeptide galanin in human erythrocytes in vitro. 2 The potencies of nootropic drugs in opposing scopolamine-induced memory loss correlate with their potencies in antagonising pentobarbital inhibition of erythrocyte glucose transport in vitro (P<0.01). Less potent nootropics, D-levetiracetam and D-pyroglutamate, have higher antagonist Ki's against pentobarbital inhibition of glucose transport than more potent L-stereoisomers (P<0.001). 3 Piracetam and TRH have no direct effects on net glucose transport, but competitively antagonise hypnotic drug inhibition of glucose transport. Other nootropics, like aniracetam and levetiracetam, while antagonising pentobarbital action, also inhibit glucose transport. Analeptics like bemigride and methamphetamine are more potent inhibitors of glucose transport than antagonists of hypnotic action on glucose transport. 4 There are similarities between amino-acid sequences in human glucose transport protein isoform 1 (GLUT1) and the benzodiazepine-binding domains of GABAA (gamma amino butyric acid) receptor subunits. Mapped on a 3D template of GLUT1, these homologies suggest that the site of diazepam and piracetam interaction is a pocket outside the central hydrophilic pore region. 5 Nootropic pyrrolidone antagonism of hypnotic drug inhibition of glucose transport in vitro may be an analogue of TRH antagonism of galanin-induced narcosis.
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Affiliation(s)
- Richard J Naftalin
- Physiology Division, Centre for Vascular Biology and Medicine, King's College London, Guy's Campus, New Hunt's House, London SE1 1UL.
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Klepper J. Impaired glucose transport into the brain: the expanding spectrum of glucose transporter type 1 deficiency syndrome. Curr Opin Neurol 2004; 17:193-6. [PMID: 15021248 DOI: 10.1097/00019052-200404000-00018] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW Glucose transporter type 1 deficiency syndrome (OMIM 606777) is a treatable epileptic encephalopathy resulting from impaired glucose transport into the brain. In recent years, the increasing number of patients has generated substantial insights into the manifestations and mechanisms of this disease. Current understanding of this novel disorder is reviewed, and recent advances in diagnosis and treatment are highlighted. RECENT FINDINGS The syndrome is now understood to be a complex neurological disorder. The clinical spectrum has recently been extended by infants with 'benign' transient hypoglycorrhachia, glucose transporter type 1 deficiency syndrome without seizures, and by adult cases. Other key findings in the last couple of years include (1) the description of electroencephalogram abnormalities, (2) a characteristic cerebral metabolic footprint in positron emission tomography imaging, and (3) the definition of molecular mechanisms and functional domains within the glucose transporter type 1 protein by in-vitro mutagenesis. The disease has also shed a new light on the mechanisms and the effectiveness of the ketogenic diet for seizure control. SUMMARY The syndrome is now well characterized in children and should be considered in any patient with intractable epilepsy. An effective therapy is available. The clinical spectrum and the molecular basis of the disease are increasingly heterogeneous and indicate complex pathogenic mechanisms that will ultimately lead to a classification on clinical, biochemical, and molecular grounds.
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Affiliation(s)
- Jörg Klepper
- Department of Pediatrics and Pediatric Neurology, University of Essen, Essen, Germany.
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