Growth inhibition and induction of apoptosis by 2-methoxyestradiol in rat osteosarcoma and malignant fibrous histiocytoma cell lines.

Methoxyestradiol (2-ME) has been found to possess antitumor activity in vivo and in vitro. It has been suggested that 2-ME induces apoptosis resulting in G2/M arrest of tumor cells. In this study, the effect of 2-ME was evaluated in rat osteosarcoma and malignant fibrous histiocytoma (MFH) cell lines. 2-ME was used at final concentrations of 100 nM to 2 IM. The effect of 2-ME on cell growth was measured by the MTS assay. Induction of apoptosis and activation of caspase-3 were investigated along with apoptosis-related gene expression. The data showed that 2-ME significantly inhibited cell growth, inducing apoptosis. The activity of caspase-3 was increased at 20 h and 40 h in both cell lines. 2-ME induced p16 expression, which was possibly involved in the apoptotic process. These results suggested that the 2-ME-induced apoptosis of rat osteosarcoma and rat MFH cells was accompanied by caspase- 3 activation through p16 induction. 2-Methoxyestradiol (2-ME) is a natural estrogenic