Effects of calcitriol and its analogue calcipotriol on proliferation and differentiation of human osteosarcoma cells.

The effects of steroid hormone calcitriol (Cal) and its analogue calcipotriol on human osteosarcoma cell line HOS-8603 were determined. When cells grew in monolayer culture in the presence of hormones, their proliferations were inhibited both in dose- and time-dependent manners. The cells showed marked morphologic changes after a 4-d treatment to apparently less transformed fibroblast-like ones. Anchorage-independent growth studies indicated that both Cal and calcipotriol at 10 nmol.L-1 inhibited colony formation by HOS-8603 cells. As a marker enzyme of the osteoblastic phenotype, alkaline phosphatase activity was induced in response to Cal or calcipotriol 100 nmol.L-1. These results suggested that Cal and calcipotriol play an important role in regulating growth and differentiation of HOS-8603 cells.