The Effects of Dexamethasone, 6 alpha-Methylprednisolone, and Retinoic Acid on the Growth and Morphology of a Rat Glioma Cell Line, C6

ABSTRACT

Glucocorticoids, dexamethasone, 6 alpha-methylprednisolone are routinely administered to brain tumor patients to reduce peritumoral edema before surgical removal of the tumor. In addition, the glucocorticoids can inhibit growth of several cell lines. Retinoic acid, a derivative of vitamin A is also known to inhibit growth of several cell lines. Sometimes inhibition of growth accompany morphological changes. In the present study, we compared the effects of dexamethasone, 6 alpha-methylprednisolone, and retinoic acid on the growth and on the morphology of a rat glioma cell line, C6. We found that all of them can maximally inhibit the growth of C6 by approximately 30%(p<0.0025) in the presence of 10 microM of either dexamethasone, 6 alpha-methylprednisolone or retinoic acid under our experimental conditions. However, only retinoic acid could induce the morphological changes of C6 at the concentrations over 1 microM concentration, which was elongation of the cells. The morphological changes were observed both at the subconfluent and confluent cell population. When mixture of 10 microM of dexamethasone and 10 microM of retinoic acid was added, no further increase in the inhibition of growth was observed compared with the inhibition obtained by adding 10 microM of dexamethasone only. The results suggest that the glucocorticoids might have effedts of growth inhibition of the glial tumor in vivo.