Desmosterol in human and experimental brain tumors in tissue culture

Desmosterol, a possible chemical indicator of brain tumors, was detected in cells of neurogenic, nitrosourea-induced rat tumors (neurinomas and gliomas, C6 cell line) and in human astrocytomas grown in lipid-poor media. A further increase in the amount of cell desmosterol was obtained when triparanol was added to media containing delipidized serum. Cholesterol was replaced almost completely by desmosterol in tumor cells grown in media containing nontoxic levels of 20,25-diazacholesterol. Desmosterol did not accumulate when these inhibitors of desmosterol-reductase were added to culture media containing cholesterol and other lipids (whole fetal calf serum). The results demonstrate that tumors of the nervous system grown in tissue culture are capable of sterol synthesis, and indicate that a central mechanism of cholesterol synthesis is operative in these cells, which may be related to the availability of exogenous cholesterol. It is concluded that these findings are relevant to clinical studies on the use of cholesterol inhibitors as tools for the detection of brain tumor activity.