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

Publisher Website
Google Scholar
Abstract
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.