Growth inhibition of clonal osteosarcoma cell-lines by low concentrations of glucocorticoid hormones

Clonal osteosarcoma cell line, ROS $\text{2}\text{3}$, showed marked inhibition of [³H]thymidine incorporation in response to low concentrations (10^?10 M) of triamcinolone acetonide and dexamethasone. Hydrocortisone and corticosterone induced inhibition at somewhat higher concentrations. The osteosarcoma cell line ROS $\text{17}\text{2}$ responded similarly to triamcinolone acetonide and dexamethasone but at higher concentrations of the hormones. In ROS $\text{2}\text{3}$ the inhibitory effects of triamcinolone acetonide were accompanied by only slight elevation in the amount of intracellular exchangeable Ca²⁺. In contrast, in primary cultures of normal rat-calvarian bone cells, [³H]thymidine incorporation was inhibited to a much lesser extent only at higher concentrations of triamcinolone acetonide (10^?7 M). The difference in the susceptibility of normal and malignant bone cells to the inhibitory effects of glucocorticoids may have potential therapeutic importance.