title: Regulation of GLUT3 and glucose uptake by the cAMP signalling pathway in the breast cancer cell line ZR-75.
abstract: Increased glucose uptake as a principal energy source is a requirement for the continued survival of tumour cells. Facilitative glucose transporter-1 (GLUT1) and -3 (GLUT3) have been previously shown to be present and regulated in breast cancer cells and are associated with poor patient prognosis. In cancer cells, the cAMP secondary messenger pathway is known to potentiate described glucose transporter activators and regulate cell fate. However, no regulation of the glucose transporters in breast cancer cells by cAMP has previously been examined. Herein, we determined in the well-characterized breast cancer cell line ZR-75, if the cAMP analogue 8-br-cAMP was capable of regulating GLUT1 and GLUT3 expression and thus glucose uptake. We demonstrated that 8-br-cAMP transiently up-regulates GLUT3 mRNA levels. The use of actinomycin-D and the cloning of 1,200 bp upstream of the human GLUT3 promoter demonstrated that this regulation was transcriptional. Immunocytochemistry and Western blotting confirmed that the increase in mRNA was reflected by an increase in protein levels. No notable regulation of GLUT1 in the presence of 8-br-cAMP was detected. Finally, we determined using the non-metabolizable glucose analogue 2-DOG if this up-regulation in GLUT3 increased glucose uptake. We observed the presence of two uptake components, one corresponding to the Km of GLUT1/4 and the other to GLUT3. A doubling in the uptake velocity was observed only at the Km corresponding to GLUT3. In conclusion, we demonstrate and characterize for the first time, an up-regulation of GLUT3 mRNA, protein and glucose uptake by the cAMP pathway in breast cancer cells.
authors.affiliation: Laboratorio de Biología Celular y Molecular, MIFAB, Universidad Nacional Andrés Bello, Santiago, Chile.
authors.forename: Ana Maria
authors.initials: AM
authors.lastname: Meneses
authors.forename: Rodolfo A
authors.initials: RA
authors.lastname: Medina
authors.forename: Sumie
authors.initials: S
authors.lastname: Kato
authors.forename: Mauricio
authors.initials: M
authors.lastname: Pinto
authors.forename: Maria Paz
authors.initials: MP
authors.lastname: Jaque
authors.forename: Isabel
authors.initials: I
authors.lastname: Lizama
authors.forename: María de los Angeles
authors.initials: Mde L
authors.lastname: García
authors.forename: Francisco
authors.initials: F
authors.lastname: Nualart
authors.forename: Gareth I
authors.initials: GI
authors.lastname: Owen
mesh_terms: D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D000242:Cyclic AMP / Q000378:metabolism*; D003847:Deoxyglucose / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D015972:Gene Expression Regulation, Neoplastic; D005947:Glucose / Q000378:metabolism*; D051274:Glucose Transporter Type 3 / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D011374:Progesterone / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction
chemical_list: D051274:Glucose Transporter Type 3; D012333:RNA, Messenger; C495687:SLC2A3 protein, human; D015124:8-Bromo Cyclic Adenosine Monophosphate; D011374:Progesterone; D003847:Deoxyglucose; D000242:Cyclic AMP; D005947:Glucose