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Anthony Carruthers - One of the best experts on this subject based on the ideXlab platform.

  • red wine and green tea flavonoids are cis allosteric activators and competitive inhibitors of glucose transporter 1 glut1 mediated sugar uptake
    Journal of Biological Chemistry, 2018
    Co-Authors: Ogooluwa A Ojelabi, Julie K De Zutter, Kenneth P Lloyd, Anthony Carruthers
    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.

  • wzb117 2 fluoro 6 m hydroxybenzoyloxy phenyl m hydroxybenzoate inhibits glut1 mediated sugar transport by binding reversibly at the exofacial sugar binding site
    Journal of Biological Chemistry, 2016
    Co-Authors: Ogooluwa A Ojelabi, Julie K De Zutter, Kenneth P Lloyd, Andrew H Simon, Anthony Carruthers
    Abstract:

    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.

  • sequence determinants of glut1 oligomerization analysis by homology scanning mutagenesis
    Journal of Biological Chemistry, 2013
    Co-Authors: Julie K De Zutter, Kara B Levine, Di Deng, Anthony Carruthers
    Abstract:

    Abstract The human blood-brain barrier glucose transport protein (GLUT1) forms homodimers and homotetramers in detergent micelles and in cell membranes, where the GLUT1 oligomeric state determines GLUT1 transport behavior. GLUT1 and the neuronal glucose transporter GLUT3 do not form heterocomplexes in human embryonic kidney 293 (HEK293) cells as judged by co-immunoprecipitation assays. Using homology-scanning mutagenesis in which GLUT1 domains are substituted with equivalent GLUT3 domains and vice versa, we show that GLUT1 transmembrane helix 9 (TM9) is necessary for optimal association of GLUT1-GLUT3 chimeras with parental GLUT1 in HEK cells. GLUT1 TMs 2, 5, 8, and 11 also contribute to a less abundant heterocomplex. Cell surface GLUT1 and GLUT3 containing GLUT1 TM9 are 4-fold more catalytically active than GLUT3 and GLUT1 containing GLUT3 TM9. GLUT1 and GLUT3 display allosteric transport behavior. Size exclusion chromatography of detergent solubilized, purified GLUT1 resolves GLUT1/lipid/detergent micelles as 6- and 10-nm Stokes radius particles, which correspond to GLUT1 dimers and tetramers, respectively. Studies with GLUTs expressed in and solubilized from HEK cells show that HEK cell GLUT1 resolves as 6- and 10-nm Stokes radius particles, whereas GLUT3 resolves as a 6-nm particle. Substitution of GLUT3 TM9 with GLUT1 TM9 causes chimeric GLUT3 to resolve as 6- and 10-nm Stokes radius particles. Substitution of GLUT1 TM9 with GLUT3 TM9 causes chimeric GLUT1 to resolve as a mixture of 6- and 4-nm particles. We discuss these findings in the context of determinants of GLUT oligomeric structure and transport function.

  • role of monosaccharide transport proteins in carbohydrate assimilation distribution metabolism and homeostasis
    Comprehensive Physiology, 2012
    Co-Authors: Anthony J Cura, Anthony Carruthers
    Abstract:

    The facilitated diffusion of glucose, galactose, fructose, urate, myoinositol, and dehydroascorbic acid in mammals is catalyzed by a family of 14 monosaccharide transport proteins called GLUTs. These transporters may be divided into three classes according to sequence similarity and function/substrate specificity. GLUT1 appears to be highly expressed in glycolytically active cells and has been coopted in vitamin C auxotrophs to maintain the redox state of the blood through transport of dehydroascorbate. Several GLUTs are definitive glucose/galactose transporters, GLUT2 and GLUT5 are physiologically important fructose transporters, GLUT9 appears to be a urate transporter while GLUT13 is a proton/myoinositol cotransporter. The physiologic substrates of some GLUTs remain to be established. The GLUTs are expressed in a tissue specific manner where affinity, specificity, and capacity for substrate transport are paramount for tissue function. Although great strides have been made in characterizing GLUT-catalyzed monosaccharide transport and mapping GLUT membrane topography and determinants of substrate specificity, a unifying model for GLUT structure and function remains elusive. The GLUTs play a major role in carbohydrate homeostasis and the redistribution of sugar-derived carbons among the various organ systems. This is accomplished through a multiplicity of GLUT-dependent glucose sensing and effector mechanisms that regulate monosaccharide ingestion, absorption, distribution, cellular transport and metabolism, and recovery/retention. Glucose transport and metabolism have coevolved in mammals to support cerebral glucose utilization. © 2012 American Physiological Society. Compr Physiol 2:863-914, 2012.

  • role of monosaccharide transport proteins in carbohydrate assimilation distribution metabolism and homeostasis
    Comprehensive Physiology, 2012
    Co-Authors: Anthony J Cura, Anthony Carruthers
    Abstract:

    The facilitated diffusion of glucose, galactose, fructose, urate, myoinositol, and dehydroascorbicacid in mammals is catalyzed by a family of 14 monosaccharide transport proteins called GLUTs. These transporters may be divided into three classes according to sequence similarity and function/substrate specificity. GLUT1 appears to be highly expressed in glycolytically active cells and has been coopted in vitamin C auxotrophs to maintain the redox state of the blood through transport of dehydroascorbate. Several GLUTs are definitive glucose/galactose transporters, GLUT2 and GLUT5 are physiologically important fructose transporters, GLUT9 appears to be a urate transporter while GLUT13 is a proton/myoinositol cotransporter. The physiologic substrates of some GLUTs remain to be established. The GLUTs are expressed in a tissue specific manner where affinity, specificity, and capacity for substrate transport are paramount for tissue function. Although great strides have been made in characterizing GLUT-catalyzed monosaccharide transport and mapping GLUT membrane topography and determinants of substrate specificity, a unifying model for GLUT structure and function remains elusive. The GLUTs play a major role in carbohydrate homeostasis and the redistribution of sugar-derived carbons among the various organ systems. This is accomplished through a multiplicity of GLUT-dependent glucose sensing and effector mechanisms that regulate monosaccharide ingestion, absorption,distribution, cellular transport and metabolism, and recovery/retention. Glucose transport and metabolism have coevolved in mammals to support cerebral glucose utilization.

Chris I Cheeseman - One of the best experts on this subject based on the ideXlab platform.

  • molecular imaging of glut1 and GLUT5 in breast cancer a multitracer positron emission tomography imaging study in mice
    Molecular Pharmacology, 2018
    Co-Authors: Melinda Wuest, Olivier-mohamad Soueidan, Ingrit Hamann, Daniel Krys, Darryl D Glubrecht, Vincent Bouvet, Alison Marshall, Brendan J Trayner, Michael Wagner, Chris I Cheeseman
    Abstract:

    Use of [18F]FDG-positron emission tomography (PET) in clinical breast cancer (BC) imaging is limited mainly by insufficient expression levels of facilitative glucose transporter (GLUT)1 in up to 50% of all patients. Fructose-specific facilitative hexose transporter GLUT5 represents an alternative biomarker for PET imaging of hexose metabolism in BC. The goal of the present study was to compare the uptake characteristics of selected hexose-based PET radiotracers in murine BC model EMT6. Uptake of 1-deoxy-1-[18F]fluoro-d-fructose (1-[18F]FDF), 6-deoxy-6-[18F]fluoro-d-fructose (6-[18F]FDF), 1-deoxy-1-[18F]fluoro-2,5-anhydro-mannitol (1-[18F]FDAM), 2-deoxy-2-[18F]fluoro-d-glucose (2-[18F]FDG), and 6-deoxy-6-[18F]fluoro-d-glucose (6-[18F]FDG) was studied in EMT6 cells, tumors, and muscle and correlated to GLUT1 and GLUT5 expression levels. Fructose-derivative 6-[18F]FDF revealed greater tumor uptake than did structural analog 1-[18F]FDF, whereas 1-[18F]FDAM with locked anomeric configuration showed similar low tumor uptake to that of 1-[18F]FDF. Glucose-derivative 6-[18F]FDG reached maximum tumor uptake at 20 minutes, with no further accumulation over time. Uptake of 2-[18F]FDG was greatest and continuously increasing owing to metabolic trapping through phosphorylation by hexokinase II. In EMT6 tumors, GLUT5 mRNA expression was 20,000-fold lower compared with GLUT1. Whereas the latter was much greater in tumor than in muscle tissue (GLUT1 50:1), the opposite was found for GLUT5 mRNA expression (GLUT5 1:6). GLUT5 protein levels were higher in tumor versus muscle tissue as determined by Western blot and immunohistochemistry. Our data suggest that tumor uptake of fructose metabolism-targeting radiotracers 1-[18F]FDF, 6-[18F]FDF, and 1-[18F]FDAM does not correlate with GLUT5 mRNA levels but is linked to GLUT5 protein levels. In conclusion, our results highlight the importance of detailed biochemical studies on GLUT protein expression levels in combination with PET imaging studies for functional characterization of GLUTs in BC.

  • fluorescent hexose conjugates establish stringent stereochemical requirement by GLUT5 for recognition and transport of monosaccharides
    ACS Chemical Biology, 2017
    Co-Authors: Olivier-mohamad Soueidan, Thomas W. Scully, Jatinder Kaur, Rashmi Panigrahi, Alexandr Belovodskiy, Carson D. Matier, Joanne M. Lemieux, Frank Wuest, Chris I Cheeseman, F G West
    Abstract:

    The specificity characteristics of transporters can be exploited for the development of novel diagnostic therapeutic probes. The facilitated hexose transporter family (GLUTs) has a distinct set of preferences for monosaccharide substrates, and while some are expressed ubiquitously (e.g., GLUT1), others are quite tissue specific (e.g., GLUT5, which is overexpressed in some breast cancer tissues). While these differences have enabled the development of new molecular probes based upon hexose- and tissue-selective uptake, substrate design for compounds targeting these GLUT transporters has been encumbered by a limited understanding of the molecular interactions at play in hexose binding and transport. Four new fluorescently labeled hexose derivatives have been prepared, and their transport characteristics were examined in two breast cancer cell lines expressing mainly GLUTs 1, 2, and 5. Our results demonstrate, for the first time, a stringent stereochemical requirement for recognition and transport by GLUT5. ...

  • new fluorinated fructose analogs as selective probes of the hexose transporter protein GLUT5
    Organic and Biomolecular Chemistry, 2015
    Co-Authors: Olivier-mohamad Soueidan, Frank Wuest, F G West, Brendan J Trayner, Tina N Grant, Jeff R Henderson, Chris I Cheeseman
    Abstract:

    Facilitated hexose transporters (GLUTs) mediate the transport of hexoses and other substrates across the membranes of numerous cell types, and while some are expressed ubiquitously (e.g., GLUT1), others are more tissue specific (e.g., GLUT5). These properties have been exploited for the imaging of cancer cells by the use of hexose based probes, including fluorinated hexose derivatives for use with positron emission tomography (PET). However, design of new probes has been hampered by a limited understanding of how GLUT transporters interact with their substrates at the molecular level. Two fluorinated fructose surrogates designed for uptake by the GLUT5 transporter are described here: 3-deoxy-3-fluoro-D-fructose (3-FDF) and 1-deoxy-1-fluoro-2,5-anhydromannitol (1-FDAM). Synthesis (both cold and radiolabeled) and in vitro analysis of their transport characteristics in two breast cancer cell lines (EMT-6 and MCF-7) expressing GLUT5 are detailed. Both analogues are readily taken up into both cancer cell lines, with uptake mediated primarily by GLUT5. They also have low IC50 values, indicating a high affinity for the transporter, suggesting that the uptake of these probes would be unaffected by endogenously circulating fructose. Selective uptake by GLUT5 was also demonstrated in Xenopus oocytes. Finally, these results are the first demonstration that a hexose existing predominantly in the pyranose ring structure (3-FDF) is transported by GLUT5, strongly suggesting that this transporter can handle both furanose and pyranose forms of fructose.

  • identification of a hydrophobic residue as a key determinant of fructose transport by the facilitative hexose transporter slc2a7 glut7
    Journal of Biological Chemistry, 2005
    Co-Authors: Andrei Manolescu, Jorge Fischbarg, Alexis Salasburgos, Chris I Cheeseman
    Abstract:

    Until recently, the only facilitated hexose transporter GLUT proteins (SLC2A) known to transport fructose were GLUTs 2 and 5. However, the recently cloned GLUT7 can also transport fructose as well as glucose. Comparison of sequence alignments indicated that GLUTs 2, 5, and 7 all had an isoleucine residue at position "314" (GLUT7), whereas the non-fructose-transporting isoforms, GLUTs 1, 3, and 4, had a valine at this position. Mutation of Ile-314 to a valine in GLUT7 resulted in a loss of fructose transport, whereas glucose transport remained completely unaffected. Similar results were obtained with GLUTs 2 and 5. Energy minimization modeling of GLUT7 indicated that Ile-314 projects from transmembrane domain 7 (TM7) into the lumen of the aqueous pore, where it could form a hydrophobic interaction with tryptophan 89 from TM2. A valine residue at 314 appeared to produce a narrowing of the vestibule when compared with the isoleucine. It is proposed that this hydrophobic interaction across the pore forms a selectivity filter restricting the access of some hexoses to the substrate binding site(s) within the aqueous channel. The presence of a selectivity filter in the extracellular vestibule of GLUT proteins would allow for subtle changes in substrate specificity without changing the kinetic parameters of the protein.

Yoshitomo Oka - One of the best experts on this subject based on the ideXlab platform.

  • targeting of glut1 GLUT5 chimeric proteins in the polarized cell line caco 2
    Molecular Endocrinology, 1997
    Co-Authors: Kouichi Inukai, Hideki Katagiri, Kuniaki Takata, Tomoichiro Asano, Hisamitsu Ishihara, Mitsuhiro Nakazaki, Masatoshi Kikuchi, Yoshio Yazaki, Yasushi Fukushima, Yoshitomo Oka
    Abstract:

    Caco-2, a human differentiated intestinal epithelial cell line, is a promising model for investigating the mechanism of polarized targeting of apical and basolateral membrane proteins. We stably transfected rat GLUT5 cDNA and rabbit GLUT1 cDNA into Caco-2 cells with an expression vector. Immunohistochemical study revealed that the GLUT5 protein expressed was localized at apical membranes and that the GLUT1 expressed was present primarily in the basolateral membranes of cells grown on permeable support. Next, to investigate the domain responsible for determining apical vs. basolateral sorting in glucose transporters, we prepared several GLUT1-GLUT5 chimeric cDNAs and transfected them into Caco-2 cells. A GLUT1 [N terminus∼sixth transmembrane domain (TM6)]-GLUT5 [intracellular loop (IL)∼C terminus] chimera was observed exclusively at the apical membrane, while GLUT1 (N terminus∼IL)-GLUT5 (TM7∼C terminus) and GLUT1 (N terminus∼TM12)-GLUT5 (C-terminal domain) chimeras were observed mainly at the basolateral m...

  • characterization of rat GLUT5 and functional analysis of chimeric proteins of glut1 glucose transporter and GLUT5 fructose transporter
    Endocrinology, 1995
    Co-Authors: Kouichi Inukai, Hideki Katagiri, Kuniaki Takata, Tomoichiro Asano, Motonobu Anai, Hisamitsu Ishihara, Mitsuhiro Nakazaki, Masatoshi Kikuchi, Yoshio Yazaki, Yoshitomo Oka
    Abstract:

    To investigate the biological and biochemical properties of GLUT5, rat GLUT5 complementary DNA was transfected into Chinese hamster ovary cells. Rat GLUT5 was exclusively targeted to the plasma membrane and exhibited a transport activity, not for glucose, but for fructose. The affinity for fructose (Km = 11.6mM) was much higher than that of GLUT2, the other glucose transporter with fructose transport activity. Interestingly, rat GLUT5 was not photolabeled with 0.5 microM cytochalasin B, whereas a similar amount of GLUT1 was adequately photolabeled under the same experimental conditions. Next, to investigate the domains required for transport of glucose/fructose in GLUT1 and/or GLUT5, several chimeric GLUT1/GLUT5 proteins were expressed, and their glucose and/or fructose transport activities were studied. The intracellular middle loop and the region encompassing the membrane spanning domains 7-12 were observed to have crucial roles in GLUT1 glucose transport, whereas replacement of the N-terminal half or the intracellular C-terminal region with the corresponding region of GLUT5 produced no marked effects on glucose transport activity. In contrast, both the N-terminal half encompassing the region from the N-terminus through the 6th membrane spanning domain and the intracellular C-terminal region were mandatory for GLUT5 fructose transport. In conclusion, GLUT5 is a transporter exclusively for fructose and the structural requirements for fructose transport are more stringent than those for glucose transport among hexose transporter proteins.

  • of rat GLUT5 and functional analysis of chime proteins of glut1 glucose transporter and GLUT5 fructose transporter
    1995
    Co-Authors: Kouichi Inukai, Hideki Katagiri, Kuniaki Takata, Tomoichiro Asano, Motonobu Anai, Hisamitsu Ishihara, Mitsuhiro Nakazaki, Masatoshi Kikuchi, Yoshio Yazaki, Yoshitomo Oka
    Abstract:

    To investigate the biological and biochemical properties of GLUT5, rat GLUT5 complementary DNA was transfected into Chinese ham- ster ovary cells. Rat GLUT5 was exclusively targeted to the plasma membrane and exhibited a transport activity, not for glucose, but for fructose. The affinity for fructose (K,,, = 11.6mM) was much higher than that of GLUTP, the other glucose transporter with fructose transport activity. Interestingly, rat GLUT5 was not photolabeled with 0.5 pM cytochalasin B, whereas a similar amount of GLUT1 was adequately photolabeled under the same experimental conditions. Next, to investigate the domains required for transport of glucose/ fructose in GLUT1 and/or GLUTS, several chimeric GLUTVGLUTS proteins were expressed, and their glucose and/or fructose transport activities were studied. The intracellular middle loop and the region encompassing the membrane spanning domains 7-12 were observed to have crucial roles in GLUT1 glucose transport, whereas replace- ment of the N-terminal half or the intracellular C-terminal region with the corresponding region of GLUT5 produced no marked effects on glucose transport activity. In contrast, both the N-terminal half encompassing the region from the N-terminus through the 6th mem- brane span&g domain and the intracellular C-term&al region were mandatorv for GLUT5 fructose transnort. In conclusion. GLUT5 is a transport& exclusively for fructose and the structural requirements for fructose transport are more stringent than those for glucose trans- port among hexose transporter proteins.

Frank Wuest - One of the best experts on this subject based on the ideXlab platform.

  • expression and function of hexose transporters glut1 glut2 and GLUT5 in breast cancer effects of hypoxia
    The FASEB Journal, 2018
    Co-Authors: Ingrit Hamann, Daniel Krys, Darryl D Glubrecht, Vincent Bouvet, Alison Marshall, Larissa Vos, John R Mackey, Melinda Wuest, Frank Wuest
    Abstract:

    Elevated growth in breast cancer (BC) activates hypoxia-inducible factor (HIF1α) and downstream, facilitative glucose transporter 1 (GLUT1), which can be visualized with 2-deoxy-2-[18F]fluoro-d-glucose ([18F]FDG). GLUT5 (fructose) and GLUT2 (glucose/fructose) might provide alternative targets for BC imaging as to why effects of hypoxia on GLUT1/2/5 levels and function were examined in human BC models. GLUT1/2/5 and HIF1α mRNA was analyzed in BC patient biopsies. In MCF10A, MCF7, and MDA-MB231 cells, [18F]FDG, 6-deoxy-6-[18F]fluoro-d-fructose (6-[18F]FDF) and [18F]-fluoroazomycin arabinoside were used in radiotracer experiments, whereas GLUT1/2/5 mRNA was analyzed with real-time PCR and protein levels determined via Western blot/immunohistochemistry. Positron emission tomography imaging was performed in MCF7 and MDA-MB231 tumor-bearing mice. Glucose/fructose/cytochalasin B reduced cellular 6-[18F]FDF uptake by 50%, indicating functional involvement of GLUT2. With GLUT5 staining lower than GLUT1, 6-[18F]FDF revealed lower uptake than [18F]FDG [standardized uptake value (SUV)6-[18F]FDF, 120 min 0.77 ± 0.06 vs. SUV[18F]FDG, 120 min 1.08 ± 0.07] in MDA-MB231 tumors and was blocked by 20% with cytochalasin B after 10 min. Whereas correspondence between 6-[18F]FDF uptake and GLUT5 protein was low, high GLUT2 levels were detected in all cell lines and tumor models. Besides GLUT1, GLUT5 seems to be regulated under hypoxia on the molecular and functional level. Additionally, results strongly support a functional involvement of GLUT2 in fructose metabolism, possibly by compensating for the weaker expression and function of GLUT5 in BC.-Hamann, I., Krys, D., Glubrecht, D., Bouvet, V., Marshall, A., Vos, L., Mackey, J. R., Wuest, M., Wuest, F. Expression and function of hexose transporters GLUT1, GLUT2, and GLUT5 in breast cancer-effects of hypoxia.

  • fluorescent hexose conjugates establish stringent stereochemical requirement by GLUT5 for recognition and transport of monosaccharides
    ACS Chemical Biology, 2017
    Co-Authors: Olivier-mohamad Soueidan, Thomas W. Scully, Jatinder Kaur, Rashmi Panigrahi, Alexandr Belovodskiy, Carson D. Matier, Joanne M. Lemieux, Frank Wuest, Chris I Cheeseman, F G West
    Abstract:

    The specificity characteristics of transporters can be exploited for the development of novel diagnostic therapeutic probes. The facilitated hexose transporter family (GLUTs) has a distinct set of preferences for monosaccharide substrates, and while some are expressed ubiquitously (e.g., GLUT1), others are quite tissue specific (e.g., GLUT5, which is overexpressed in some breast cancer tissues). While these differences have enabled the development of new molecular probes based upon hexose- and tissue-selective uptake, substrate design for compounds targeting these GLUT transporters has been encumbered by a limited understanding of the molecular interactions at play in hexose binding and transport. Four new fluorescently labeled hexose derivatives have been prepared, and their transport characteristics were examined in two breast cancer cell lines expressing mainly GLUTs 1, 2, and 5. Our results demonstrate, for the first time, a stringent stereochemical requirement for recognition and transport by GLUT5. ...

  • Fluorescent Hexose Conjugates Establish Stringent Stereochemical Requirement by GLUT5 for Recognition and Transport of Monosaccharides
    2017
    Co-Authors: Olivier-mohamad Soueidan, Thomas W. Scully, Jatinder Kaur, Rashmi Panigrahi, Alexandr Belovodskiy, Carson D. Matier, Joanne M. Lemieux, Frank Wuest, Chris Cheeseman
    Abstract:

    The specificity characteristics of transporters can be exploited for the development of novel diagnostic therapeutic probes. The facilitated hexose transporter family (GLUTs) has a distinct set of preferences for monosaccharide substrates, and while some are expressed ubiquitously (e.g., GLUT1), others are quite tissue specific (e.g., GLUT5, which is overexpressed in some breast cancer tissues). While these differences have enabled the development of new molecular probes based upon hexose- and tissue-selective uptake, substrate design for compounds targeting these GLUT transporters has been encumbered by a limited understanding of the molecular interactions at play in hexose binding and transport. Four new fluorescently labeled hexose derivatives have been prepared, and their transport characteristics were examined in two breast cancer cell lines expressing mainly GLUTs 1, 2, and 5. Our results demonstrate, for the first time, a stringent stereochemical requirement for recognition and transport by GLUT5. 6-NBDF, in which all substituents are in the d-fructose configuration, is taken up rapidly into both cell lines via GLUT5. On the other hand, inversion of a single stereocenter at C-3 (6-NBDP), C-4 (6-NBDT), or C-5 (6-NDBS) results in selective transport via GLUT1. An in silico docking study employing the recently published GLUT5 crystal structure confirms this stereochemical dependence. This work provides insight into hexose-GLUT interactions at the molecular level and will facilitate structure-based design of novel substrates targeting individual members of the GLUT family and forms the basis of new cancer imaging or therapeutic agents

  • new fluorinated fructose analogs as selective probes of the hexose transporter protein GLUT5
    Organic and Biomolecular Chemistry, 2015
    Co-Authors: Olivier-mohamad Soueidan, Frank Wuest, F G West, Brendan J Trayner, Tina N Grant, Jeff R Henderson, Chris I Cheeseman
    Abstract:

    Facilitated hexose transporters (GLUTs) mediate the transport of hexoses and other substrates across the membranes of numerous cell types, and while some are expressed ubiquitously (e.g., GLUT1), others are more tissue specific (e.g., GLUT5). These properties have been exploited for the imaging of cancer cells by the use of hexose based probes, including fluorinated hexose derivatives for use with positron emission tomography (PET). However, design of new probes has been hampered by a limited understanding of how GLUT transporters interact with their substrates at the molecular level. Two fluorinated fructose surrogates designed for uptake by the GLUT5 transporter are described here: 3-deoxy-3-fluoro-D-fructose (3-FDF) and 1-deoxy-1-fluoro-2,5-anhydromannitol (1-FDAM). Synthesis (both cold and radiolabeled) and in vitro analysis of their transport characteristics in two breast cancer cell lines (EMT-6 and MCF-7) expressing GLUT5 are detailed. Both analogues are readily taken up into both cancer cell lines, with uptake mediated primarily by GLUT5. They also have low IC50 values, indicating a high affinity for the transporter, suggesting that the uptake of these probes would be unaffected by endogenously circulating fructose. Selective uptake by GLUT5 was also demonstrated in Xenopus oocytes. Finally, these results are the first demonstration that a hexose existing predominantly in the pyranose ring structure (3-FDF) is transported by GLUT5, strongly suggesting that this transporter can handle both furanose and pyranose forms of fructose.

Olivier-mohamad Soueidan - One of the best experts on this subject based on the ideXlab platform.

  • molecular imaging of glut1 and GLUT5 in breast cancer a multitracer positron emission tomography imaging study in mice
    Molecular Pharmacology, 2018
    Co-Authors: Melinda Wuest, Olivier-mohamad Soueidan, Ingrit Hamann, Daniel Krys, Darryl D Glubrecht, Vincent Bouvet, Alison Marshall, Brendan J Trayner, Michael Wagner, Chris I Cheeseman
    Abstract:

    Use of [18F]FDG-positron emission tomography (PET) in clinical breast cancer (BC) imaging is limited mainly by insufficient expression levels of facilitative glucose transporter (GLUT)1 in up to 50% of all patients. Fructose-specific facilitative hexose transporter GLUT5 represents an alternative biomarker for PET imaging of hexose metabolism in BC. The goal of the present study was to compare the uptake characteristics of selected hexose-based PET radiotracers in murine BC model EMT6. Uptake of 1-deoxy-1-[18F]fluoro-d-fructose (1-[18F]FDF), 6-deoxy-6-[18F]fluoro-d-fructose (6-[18F]FDF), 1-deoxy-1-[18F]fluoro-2,5-anhydro-mannitol (1-[18F]FDAM), 2-deoxy-2-[18F]fluoro-d-glucose (2-[18F]FDG), and 6-deoxy-6-[18F]fluoro-d-glucose (6-[18F]FDG) was studied in EMT6 cells, tumors, and muscle and correlated to GLUT1 and GLUT5 expression levels. Fructose-derivative 6-[18F]FDF revealed greater tumor uptake than did structural analog 1-[18F]FDF, whereas 1-[18F]FDAM with locked anomeric configuration showed similar low tumor uptake to that of 1-[18F]FDF. Glucose-derivative 6-[18F]FDG reached maximum tumor uptake at 20 minutes, with no further accumulation over time. Uptake of 2-[18F]FDG was greatest and continuously increasing owing to metabolic trapping through phosphorylation by hexokinase II. In EMT6 tumors, GLUT5 mRNA expression was 20,000-fold lower compared with GLUT1. Whereas the latter was much greater in tumor than in muscle tissue (GLUT1 50:1), the opposite was found for GLUT5 mRNA expression (GLUT5 1:6). GLUT5 protein levels were higher in tumor versus muscle tissue as determined by Western blot and immunohistochemistry. Our data suggest that tumor uptake of fructose metabolism-targeting radiotracers 1-[18F]FDF, 6-[18F]FDF, and 1-[18F]FDAM does not correlate with GLUT5 mRNA levels but is linked to GLUT5 protein levels. In conclusion, our results highlight the importance of detailed biochemical studies on GLUT protein expression levels in combination with PET imaging studies for functional characterization of GLUTs in BC.

  • fluorescent hexose conjugates establish stringent stereochemical requirement by GLUT5 for recognition and transport of monosaccharides
    ACS Chemical Biology, 2017
    Co-Authors: Olivier-mohamad Soueidan, Thomas W. Scully, Jatinder Kaur, Rashmi Panigrahi, Alexandr Belovodskiy, Carson D. Matier, Joanne M. Lemieux, Frank Wuest, Chris I Cheeseman, F G West
    Abstract:

    The specificity characteristics of transporters can be exploited for the development of novel diagnostic therapeutic probes. The facilitated hexose transporter family (GLUTs) has a distinct set of preferences for monosaccharide substrates, and while some are expressed ubiquitously (e.g., GLUT1), others are quite tissue specific (e.g., GLUT5, which is overexpressed in some breast cancer tissues). While these differences have enabled the development of new molecular probes based upon hexose- and tissue-selective uptake, substrate design for compounds targeting these GLUT transporters has been encumbered by a limited understanding of the molecular interactions at play in hexose binding and transport. Four new fluorescently labeled hexose derivatives have been prepared, and their transport characteristics were examined in two breast cancer cell lines expressing mainly GLUTs 1, 2, and 5. Our results demonstrate, for the first time, a stringent stereochemical requirement for recognition and transport by GLUT5. ...

  • Fluorescent Hexose Conjugates Establish Stringent Stereochemical Requirement by GLUT5 for Recognition and Transport of Monosaccharides
    2017
    Co-Authors: Olivier-mohamad Soueidan, Thomas W. Scully, Jatinder Kaur, Rashmi Panigrahi, Alexandr Belovodskiy, Carson D. Matier, Joanne M. Lemieux, Frank Wuest, Chris Cheeseman
    Abstract:

    The specificity characteristics of transporters can be exploited for the development of novel diagnostic therapeutic probes. The facilitated hexose transporter family (GLUTs) has a distinct set of preferences for monosaccharide substrates, and while some are expressed ubiquitously (e.g., GLUT1), others are quite tissue specific (e.g., GLUT5, which is overexpressed in some breast cancer tissues). While these differences have enabled the development of new molecular probes based upon hexose- and tissue-selective uptake, substrate design for compounds targeting these GLUT transporters has been encumbered by a limited understanding of the molecular interactions at play in hexose binding and transport. Four new fluorescently labeled hexose derivatives have been prepared, and their transport characteristics were examined in two breast cancer cell lines expressing mainly GLUTs 1, 2, and 5. Our results demonstrate, for the first time, a stringent stereochemical requirement for recognition and transport by GLUT5. 6-NBDF, in which all substituents are in the d-fructose configuration, is taken up rapidly into both cell lines via GLUT5. On the other hand, inversion of a single stereocenter at C-3 (6-NBDP), C-4 (6-NBDT), or C-5 (6-NDBS) results in selective transport via GLUT1. An in silico docking study employing the recently published GLUT5 crystal structure confirms this stereochemical dependence. This work provides insight into hexose-GLUT interactions at the molecular level and will facilitate structure-based design of novel substrates targeting individual members of the GLUT family and forms the basis of new cancer imaging or therapeutic agents

  • new fluorinated fructose analogs as selective probes of the hexose transporter protein GLUT5
    Organic and Biomolecular Chemistry, 2015
    Co-Authors: Olivier-mohamad Soueidan, Frank Wuest, F G West, Brendan J Trayner, Tina N Grant, Jeff R Henderson, Chris I Cheeseman
    Abstract:

    Facilitated hexose transporters (GLUTs) mediate the transport of hexoses and other substrates across the membranes of numerous cell types, and while some are expressed ubiquitously (e.g., GLUT1), others are more tissue specific (e.g., GLUT5). These properties have been exploited for the imaging of cancer cells by the use of hexose based probes, including fluorinated hexose derivatives for use with positron emission tomography (PET). However, design of new probes has been hampered by a limited understanding of how GLUT transporters interact with their substrates at the molecular level. Two fluorinated fructose surrogates designed for uptake by the GLUT5 transporter are described here: 3-deoxy-3-fluoro-D-fructose (3-FDF) and 1-deoxy-1-fluoro-2,5-anhydromannitol (1-FDAM). Synthesis (both cold and radiolabeled) and in vitro analysis of their transport characteristics in two breast cancer cell lines (EMT-6 and MCF-7) expressing GLUT5 are detailed. Both analogues are readily taken up into both cancer cell lines, with uptake mediated primarily by GLUT5. They also have low IC50 values, indicating a high affinity for the transporter, suggesting that the uptake of these probes would be unaffected by endogenously circulating fructose. Selective uptake by GLUT5 was also demonstrated in Xenopus oocytes. Finally, these results are the first demonstration that a hexose existing predominantly in the pyranose ring structure (3-FDF) is transported by GLUT5, strongly suggesting that this transporter can handle both furanose and pyranose forms of fructose.