Neutral and
acidic glycosphingolipids of Friend cells were characterized in 1) undifferentiated Friend cells (745A), 2) differentiated Friend cells induced with
dimethyl-sulfoxide, and 3) solid
tumors grown in mice after subcutaneous implantation of Friend cells. The structures of the isolated
glycosphingolipids were determined by means of compositional analysis, methylation analysis and
enzyme treatment.
Gangliosides GD1a and N-acetylgalactosaminyl-GD1a, followed by GM1a and GM2, were the main
gangliosides in undifferentiated Friend cells. GD1a and N-acetylgalactosaminyl-GD1a accounted for 45 and 25% of the total
gangliosides, respectively. On differentiation,
ganglioside GM2 decreased significantly, from 10% to a trace amount. In solid
tumors, GD1a was the major
ganglioside, whereas in contrast to the situation in the cultured cells, N-acetylgalactosaminyl-GD1a was almost completely absent, and
ganglioside GM1b, but not GM1a, was detected. In addition,
ganglioside GD1 alpha was detected in the solid
tumors.
Galactosylceramide,
glucosylceramide, and
lactosylceramide were the main neutral components in both types of cells, while
globotetraosylceramide (globoside), IV3-N-acetyl-galactosaminyl
globotetraosylceramide (
Forssman glycolipid) and
gangliotetraosylceramide (GA1) were major in solid
tumors grown in vivo.