The GPI-linked Ly-6 antigen E48 regulates expression levels of the FX enzyme and of E-selectin ligands on head and neck squamous carcinoma cells.

Abstract

By differential display we demonstrated that antibody-mediated ligation of the GPI-linked protein product of E48, a newly discovered human Ly-6 gene, up-regulates the expression of the FX enzyme in 3 lines of head and neck squamous carcinoma cells. FX is responsible for the last step in the synthesis of GDP-L-fucose. The up-regulation of FX was E48 ligand-specific. 22AWT head and neck squamous carcinoma cells expressing high levels of E48 expressed significantly higher levels of FX than the E48 antisense transfected 22AWT cells (8-3 cells). The former cells also expressed higher levels of two major fucosylated glycans (the selectin ligand, Sialyl Lewis a, and VIM-2) than the E48 antisense transfectants. Conversely, transfection of cells from the 14CWT line expressing very low levels of E48 with E48 cDNA caused an up-regulated expression of FX and of the two fucosylated glycans in the 14C-CMV16 transfectants. Moreover, the expression levels of Sialyl Lewis a was significantly up-regulated on HNSCC upon ligation of E48 by anti-E48 antibodies. The functional significance of the E48-mediated up-regulation of Sialyl Lewis a was demonstrated in rolling experiments on E-selectin bearing surfaces under physiological conditions of shear flow and on tumor necrosis factor alpha-activated human umbilical venous endothelial cells. Only high E48/FX/Sialyl Lewis a expressing 14C-CMV16 cells could roll on purified E-selectin or establish E-selectin dependent rolling on the activated human umbilical venous endothelial cells. Low E48/FX/Sialyl Lewis a expressing 14CWT cells did not roll. These results show that E48 controls the expression of the FX enzyme and of certain fucosylated E-selectin ligands by HNSCC. E48 may thus function as a key regulator of the adhesiveness of these tumor cells to inflamed vessel walls expressing E-selectin.

• Authors: R Eshel, A Zanin, O Sagi-Assif, T Meshel, N I Smorodinsky, O Dwir, R Alon, R Brakenhoff, G van Dongen, I P Witz
• Journal: The Journal of biological chemistry (J Biol Chem) Vol. 275 Issue 17 Pg. 12833-40 (Apr 28 2000) ISSN: 0021-9258 [Print] United States
• PMID: 10777581 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antigens, Ly
• CA-19-9 Antigen
• DNA, Complementary
• E-Selectin
• Escherichia coli Proteins
• Glycosylphosphatidylinositols
• Ligands
• Multienzyme Complexes
• Oligosaccharides
• wcaG protein, E coli
• Ketone Oxidoreductases
• Carbohydrate Epimerases

Topics

• Antigens, Ly (metabolism, physiology)
• CA-19-9 Antigen
• Carbohydrate Epimerases (metabolism)
• Carcinoma, Squamous Cell (metabolism)
• Cell Line
• DNA, Complementary (metabolism)
• Down-Regulation
• E-Selectin (metabolism)
• Electrophoresis, Polyacrylamide Gel
• Endothelium, Vascular (metabolism)
• Escherichia coli Proteins
• Flow Cytometry
• Glycosylphosphatidylinositols (metabolism, physiology)
• Head and Neck Neoplasms (metabolism)
• Humans
• Ketone Oxidoreductases (metabolism)
• Ligands
• Multienzyme Complexes (metabolism)
• Oligosaccharides (metabolism)
• Stress, Mechanical
• Time Factors
• Transfection
• Tumor Cells, Cultured
• Umbilical Cord (metabolism)
• Up-Regulation