The study of sclareol in inhibiting proliferation of osteosarcoma cells by apoptotic induction and loss of mitochondrial membrane potential.

Sclareol (sclarcol) is an organic compound extracted from sage clary plants. Recent study has showed its anti-tumor effects against breast cancer, gastric carcinoma, osteosarcoma and colorectal cancer. However, its exact mechanisms in inhibiting tumor growth remain unknown. This study thus observed the effect of sclareol on the proliferation of osteosarcoma cells, in an attempt to investigate the role of sclarcol on osteosarcoma growth. MG63 osteosarcoma cell was treated with different concentrations of sclarcol. CCK8 assay was used to test its effect on cell proliferation. LC50 value was then determined to obtain optimal treatment dose. MG63 cells were then divided into control and drug treated group, for measuring apoptosis and mitochondrial membrane potential by flow cytometry, and the expression of cytochrome c, Bax and Bcl-2 by western blot. CCK8 analysis showed that sclareol inhibited MG63 cell proliferation, with an LC50 value at 11.0 μM. Flow cytometry results showed the apoptotic cell ratio was 13.8%, 24.1% and 37.3% after treated with 2.0 μM, 4.0 μM and 8.0 μM sclareol respectively. Compared to control group, sclareol significantly depressed mitochondrial membrane potential of MG63 cells, increased the expression of cytochrome c and Bax, but decreased Bcl-2 expression. In conclusion, Sclareol can inhibit the proliferation of MG63 cells, and induce cell apoptosis and decrease mitochondrial membrane potential suggesting the inhibition of osteosarcoma cells by sclareol might be via both apoptosis induction and decreasing mitochondrial membrane potential.