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The impact of N- and O-glycosylation on the functions of Glut-1 transporter in human thyroid anaplastic cells

2003; Elsevier BV; Volume: 1621; Issue: 1 Linguagem: Inglês

10.1016/s0304-4165(03)00050-3

1872-8006

Nezha Samih, Sonia Hovsépian, Frédéric Notel, Maëlle Prorok, Hélène Zattara‐Cannoni, Sylvie Mathieu, Dominique Lombardo, Guy Fayet, Assou El‐Battari,

Cancer-related Molecular Pathways

It has been previously shown that glucose transporter Glut-1 expression was detectable by immunostaining in tissue sections from anaplastic carcinoma, but not in normal thyroid tissue. Using human thyroid anaplastic carcinoma cells, we studied the mechanism by which Glut-1 molecules are translocated from the endoplasmic reticulum to the cell surface. The contribution of N- and O-linked glycans for the translocation and activity of Glut-1 transporter is emphasized. The inhibition of N-glycosylation with tunicamycin (TM) led to a 50% decrease in glucose transport while glycosylated and unglycosylated forms of Glut-1 were found at the cell surface. However, the inhibition of N-linked oligosaccharide processing with deoxymannojirimycin (dMJ) and swainsonine (SW) influenced neither the intracellular trafficking nor the activity of the transporter. On the other hand, Glut-1 bound to the O-linked glycan-specific lectin jacalin and the O-glycosylation inhibitor benzyl-N-acetylgalactosamine dramatically inhibited glucose transport. These results show that O- and N-linked oligosaccharides arbored by Glut-1 are essential for glucose transport in anaplastic carcinoma cells. The quantitative and qualitative alterations of Glut-1 glycosylation and the increase in glucose transport are associated with the anaplastic phenotype of human thyroid cells.