Sp. Zamoraleon et al., EXPRESSION OF THE FRUCTOSE TRANSPORTER GLUT5 IN HUMAN BREAST-CANCER, Proceedings of the National Academy of Sciences of the United Statesof America, 93(5), 1996, pp. 1847-1852
The primary metabolic characteristic of malignant cells is an increase
d uptake of glucose and its anaerobic metabolism. We studied the expre
ssion and function of the glucose transporters in human breast cancer
cell lines and analyzed their expression in normal and neoplastic prim
ary human breast tissue. Hexose uptake assays and immunoblotting exper
iments revealed that the breast carcinoma cell lines MCF-7 and MDA-468
express the glucose transporters GLUT1 and GLUT2, isoforms expressed
in both normal and neoplastic breast tissue. We also found that the br
east cancer cell lines transport fructose and express the fructose tra
nsporter GLUT5. Immunolocalization studies revealed that GLUT5 is high
ly expressed in vivo in human breast cancer but is absent in normal hu
man breast tissue. These findings indicate that human breast cancer ce
lls have a specialized capacity to transport fructose, a metabolic sub
strate believed to be used by few human tissues. Identification of a h
igh-affinity fructose transporter on human breast cancer cells opens o
pportunities to develop novel strategies for early diagnosis and treat
ment of breast cancer.