Altered metabolism and cell surface expression of glycosphingolipids caused by vitamin E in cultured murine (K3T3) reticulum sarcoma cells.

Vitamin E caused a generalized reduction in the metabolism and cell surface expression of glycosphingolipids (GSL) in cultured Kirsten murine sarcoma virus-transformed nonproducer (K3T3) cells. Metabolism of gangliosides was decreased two- to fourfold in cells treated for 72 hr with 1 and 2 micrograms/ml but not with 12 micrograms/ml vitamin E compared to control cultures. This was demonstrated by a quantitative reduction in precursor 3H-galactose label incorporated in ganglioside fraction and further substantiated by thin layer chromatography of colorimetrically and radiochemically detected GSL homologues. The composition of neutral GSL homologues was only slightly changed. The cell surface expressions of sialoglycoconjugates, analyzed by selective periodate-borotritide labeling, were also diminished quantitatively. These results are discussed in light of a previously demonstrated increase in antigenicity of K3T3 cells treated with vitamin E and the reduced tumorigenicity of these cells when transplanted into mice fed vitamin E-supplemented diets.