ALTERED MEMBRANE LIPID-COMPOSITION IN A HUMAN MENINGOSARCOMA

In a sample of meningosarcoma, obtained at the time of surgery, the am ount of total gangliosides and phospholipids was examined, together wi th the cholesterol content and the distribution of different gangliosi de and phospholipid species. The phosphatidylinositol, phosphatidylino sitol-4-phosphate, phosphatidylinositol-4, 5-bisphosphate and phosphat idylcholine fatty acid composition was also analyzed. The ganglioside pattern in the meningosarcoma was different from the previously report ed pattern in meningiomas of different histological origin, showing a higher concentration of GD3, indicating that the so-called b pathway o f ganglioside biosynthesis was the preferred one in this type of tumor ; moreover the percentage content of polysialylated gangliosides was v ery low. Cholesterol and phospholipid content was lower than in mening iomas; the phosphatidylcholine increase and the sphingomyelin decrease would indicate a lower membrane microviscosity, a characteristic of t umor cells. Phosphoinositide and phosphatidylcholine fatty acid analys is revealed a considerable amount of docosahexaenoic acid. This abnorm al presence of this fatty acid could lead to the production, after rec eptor stimulation, of a diacylglycerol containing docosahexaenoic acid , which, in turn, could be responsible for an altered activation patte rn of protein kinase C, in this way promoting carcinogenesis.