Suppression of proliferation and neurite extension of human neuroblastoma SH‐SY5Y cells on immobilized Psathyrella velutina lectin

Glycoproteins from mammalian brain tissues contain unique N‐linked oligosaccharides terminating with β‐ N ‐acetylglucosamine residues. Lectin blot analysis of membrane glycoprotein samples from human neuroblastoma SH‐SY5Y cells showed that several protein bands bind to Psathylera velutina lectin (PVL), which interacts with β‐ N ‐acetylglucosamine‐terminating oligosaccharides. No lectin positive bands were detected by digestion with jack bean β‐ N ‐acetyl‐hexosaminidase or N ‐glycanase before incubation with the lectin, indicating that the cells contain β‐ N ‐acetylglucosamine‐terminating N‐linked oligosaccharides. When cells were cultured in dishes with different concentrations of PVL, the cell proliferation was inhibited in a dose‐dependent manner. Similarly, the neurite extension, which was stimulated with nerve growth factor, was also inhibited in a manner dependent on the lectin dose. Cell proliferation and neurite extension were recovered by the addition of 10 mM N ‐acetylglucosamine into the medium. Immunoblot analysis of the activation of mitogen‐activated protein (MAP) kinases and protein kinase C revealed that phosphorylation of 42‐kDa and 44‐kDa MAP kinases and 80‐kDa protein kinase C are inhibited when SH‐SY5Y cells are cultured in PVL‐coated dishes, but are restored by the addition of the haptenic sugar into the medium, indicating that MAP kinase and protein kinase C pathways are inhibited by interaction with immobilized PVL. These results indicate that β‐ N ‐acetylglucosamine‐terminating N‐linked oligosaccharides expressed on neural cells can induce intracellular signals upon binding to extracellular receptors, and are important for growth regulation of neural cells. © 2003 Wiley‐Liss, Inc.