title: Glut-1 and hexokinase expression: relationship with 2-fluoro-2-deoxy-D-glucose uptake in A431 and T47D cells in culture.
abstract: Uptake of 2-[18F]-2-deoxy-D-glucose (FDG) has been used as a marker of increased glucose metabolism to visualize, stage, and monitor progression of human cancers with positron emission tomography. Many human tumors have been shown to overexpress the Glut-1 glucose transport protein. The aim of this study is to define whether a quantitative relationship exists between the amount of Glut-1 expressed by cells and their ability to accumulate FDG. We characterized the expression of the known facilitative and sodium-dependent glucose transporter isoforms in six different cancer cell lines used in our laboratory (A431, MDA-MB-231, T47D, CaCo II, MCF7, and HepG2). A431 and T47D cells express, respectively, the highest and lowest amount of Glut-1 mRNA by Northern blot of all of the cells analyzed, and no other glucose transporter isoforms were detectable by this method in both cell lines. Both total and plasma membrane-associated Glut-1 protein levels were higher in A431 than in T47D cells, consistent with the higher Glut-1 mRNA levels. However, T47D cells accumulate FDG more rapidly than do A431 cells. 3-O-Methylglucose transport is higher in A431 cells. Although hexokinase I and II mRNA levels are higher in A431 cells than in T47D cells, the ability of mitochondrial preparations to phosphorylate FDG is higher in T47D cells. Our data indicate that in these cultured cells, FDG uptake correlates better with FDG phosphorylating activity of mitochondrial preparations rather than the level of expression of the Glut-1 or hexokinase I and II genes.
authors.affiliation: Nuclear Medicine Department, Clinical Center, NIH, Bethesda, Maryland 20892-1180, USA.
authors.forename: L
authors.initials: L
authors.lastname: Aloj
authors.forename: C
authors.initials: C
authors.lastname: Caracó
authors.forename: E
authors.initials: E
authors.lastname: Jagoda
authors.forename: W C
authors.initials: WC
authors.lastname: Eckelman
authors.forename: R D
authors.initials: RD
authors.lastname: Neumann
mesh_terms: D001692:Biological Transport; D001943:Breast Neoplasms; D006528:Carcinoma, Hepatocellular; D002294:Carcinoma, Squamous Cell; D002462:Cell Membrane / Q000378:metabolism; D003110:Colonic Neoplasms; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics*; D015971:Gene Expression Regulation, Enzymologic; D051272:Glucose Transporter Type 1; D006593:Hexokinase / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D008113:Liver Neoplasms; D009004:Monosaccharide Transport Proteins / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
chemical_list: D051272:Glucose Transporter Type 1; D007527:Isoenzymes; D009004:Monosaccharide Transport Proteins; D012333:RNA, Messenger; D019275:Radiopharmaceuticals; C495677:SLC2A1 protein, human; D019788:Fluorodeoxyglucose F18; D006593:Hexokinase