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.
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.
Eshel
R
R
Department of Cell Research and Immunology and Ela Kodesz Institute for Research on Cancer Development and Prevention, Tel Aviv University, 69978 Tel Aviv, Israel.
Zanin
A
A
Sagi-Assif
O
O
Meshel
T
T
Smorodinsky
N I
NI
Dwir
O
O
Alon
R
R
Brakenhoff
R
R
van Dongen
G
G
Witz
I P
IP
D000950:Antigens, Ly / Q000378:metabolism / Q000502:physiology*; D018395:CA-19-9 Antigen; D002238:Carbohydrate Epimerases / Q000378:metabolism*; D002294:Carcinoma, Squamous Cell / Q000378:metabolism*; D002460:Cell Line; D018076:DNA, Complementary / Q000378:metabolism; D015536:Down-Regulation; D019040:E-Selectin / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004730:Endothelium, Vascular / Q000378:metabolism; D029968:Escherichia coli Proteins; D005434:Flow Cytometry; D017261:Glycosylphosphatidylinositols / Q000378:metabolism / Q000502:physiology*; D006258:Head and Neck Neoplasms / Q000378:metabolism*; D006801:Humans; D007658:Ketone Oxidoreductases / Q000378:metabolism*; D008024:Ligands; D009097:Multienzyme Complexes / Q000378:metabolism*; D009844:Oligosaccharides / Q000378:metabolism; D013314:Stress, Mechanical; D013997:Time Factors; D014162:Transfection; D014407:Tumor Cells, Cultured; D014470:Umbilical Cord / Q000378:metabolism; D015854:Up-Regulation
D000950:Antigens, Ly; D018395:CA-19-9 Antigen; D018076:DNA, Complementary; D019040:E-Selectin; D029968:Escherichia coli Proteins; D017261:Glycosylphosphatidylinositols; D008024:Ligands; D009097:Multienzyme Complexes; D009844:Oligosaccharides; C110682:wcaG protein, E coli; D007658:Ketone Oxidoreductases; D002238:Carbohydrate Epimerases