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Identification of druggable small molecule antagonists of the Plasmodium falciparum hexose transporter PfHT and assessment of ligand access to the glucose permeation pathway via FLAG-mediated protein engineering.
Heitmeier, Monique R; Hresko, Richard C; Edwards, Rachel L; Prinsen, Michael J; Ilagan, Ma Xenia G; Odom John, Audrey R; Hruz, Paul W.
Afiliación
  • Heitmeier MR; Department of Pediatrics, Washington University School of Medicine, St Louis, MO, United States of America.
  • Hresko RC; Department of Pediatrics, Washington University School of Medicine, St Louis, MO, United States of America.
  • Edwards RL; Department of Pediatrics, Washington University School of Medicine, St Louis, MO, United States of America.
  • Prinsen MJ; High Throughput Screening Center, Washington University School of Medicine, St Louis, MO, United States of America.
  • Ilagan MXG; High Throughput Screening Center, Washington University School of Medicine, St Louis, MO, United States of America.
  • Odom John AR; Department of Pediatrics, Washington University School of Medicine, St Louis, MO, United States of America.
  • Hruz PW; Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO, United States of America.
PLoS One ; 14(5): e0216457, 2019.
Article en En | MEDLINE | ID: mdl-31071153
Although the Plasmodium falciparum hexose transporter PfHT has emerged as a promising target for anti-malarial therapy, previously identified small-molecule inhibitors have lacked promising drug-like structural features necessary for development as clinical therapeutics. Taking advantage of emerging insight into structure/function relationships in homologous facilitative hexose transporters and our novel high throughput screening platform, we investigated the ability of compounds satisfying Lipinksi rules for drug likeness to directly interact and inhibit PfHT. The Maybridge HitFinder chemical library was interrogated by searching for compounds that reduce intracellular glucose by >40% at 10 µM. Testing of initial hits via measurement of 2-deoxyglucose (2-DG) uptake in PfHT over-expressing cell lines identified 6 structurally unique glucose transport inhibitors. WU-1 (3-(2,6-dichlorophenyl)-5-methyl-N-[2-(4-methylbenzenesulfonyl)ethyl]-1,2-oxazole-4-carboxamide) blocked 2-DG uptake (IC50 = 5.8 ± 0.6 µM) with minimal effect on the human orthologue class I (GLUTs 1-4), class II (GLUT8) and class III (GLUT5) facilitative glucose transporters. WU-1 showed comparable potency in blocking 2-DG uptake in freed parasites and inhibiting parasite growth, with an IC50 of 6.1 ± 0.8 µM and EC50 of 5.5 ± 0.6 µM, respectively. WU-1 also directly competed for N-[2-[2-[2-[(N-biotinylcaproylamino)ethoxy)ethoxyl]-4-[2-(trifluoromethyl)-3H-diazirin-3-yl]benzoyl]-1,3-bis(mannopyranosyl-4-yloxy)-2-propylamine (ATB-BMPA) binding and inhibited the transport of D-glucose with an IC50 of 5.9 ± 0.8 µM in liposomes containing purified PfHT. Kinetic analysis revealed that WU-1 acts as a non-competitive inhibitor of zero-trans D-fructose uptake. Decreased potency for WU-1 and the known endofacial ligand cytochalasin B was observed when PfHT was engineered to contain an N-terminal FLAG tag. This modification resulted in a concomitant increase in affinity for 4,6-O-ethylidene-α-D-glucose, an exofacially directed transport antagonist, but did not alter the Km for 2-DG. Taken together, these data are consistent with a model in which WU-1 binds preferentially to the transporter in an inward open conformation and support the feasibility of developing potent and selective PfHT antagonists as a novel class of anti-malarial drugs.
Asunto(s)

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Plasmodium falciparum / Proteínas de Transporte de Monosacáridos / Proteínas Protozoarias / Antimaláricos Tipo de estudio: Diagnostic_studies Límite: Humans Idioma: En Revista: PLoS One Asunto de la revista: CIENCIA / MEDICINA Año: 2019 Tipo del documento: Article País de afiliación: Estados Unidos Pais de publicación: Estados Unidos

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Plasmodium falciparum / Proteínas de Transporte de Monosacáridos / Proteínas Protozoarias / Antimaláricos Tipo de estudio: Diagnostic_studies Límite: Humans Idioma: En Revista: PLoS One Asunto de la revista: CIENCIA / MEDICINA Año: 2019 Tipo del documento: Article País de afiliación: Estados Unidos Pais de publicación: Estados Unidos