The composition of glycosphingolipids and the effect of neuraminidase on cultured glioma cell lines

The composition of glycosphingolipid on human cultured glioma cell line U 251 and rat glioma cell line C6 was analysed by high performance thin layer chromatography. As a result, the major gangliosides were simple gangliosides such as GM3 (U 251: 7.7%, C6: 84.3%), GM2 (U 251: 32.6%) and SPG (U 251: 30.0%) on glioma cells whereas the major neutral glycosphingolipids were CDH, CTH and globoside. After treatment with neuraminidase 2.92 nmol/mg dry weight and 3.73 nmol/mg dry weight of sialic acid were freed from U 251 cells and C6 cell, but only 8.11% (U 251 cell) and 11.24% (C 6 cell) of these sialic acids originated from glycolipid, and thus the major part of sialic acid might be released from glycoprotein of the cells. The gangliosides that react to neuraminidase are SPG, GD1a and GD1b in U 251 cells and are GM1a and little GM3 in C 6 cells. The biolabelling study using N-acetyl-14C-mannosamine as a precursor of sialic acid demonstrated that the precursor was mainly incorporated into both or either of GM3 and SPG in the acidic glycolipid fraction. In addition, no significant change on proliferation and morphology of glioma cells after neuraminidase treatment was observed in this study.