Antitumor activity of cynanauriculoside A and its effect of apoptosis induction in tumor cells

Objective To investigate the antitumor effect of cynanauriculoside A(CA) isolated from the root of Cynanchum auriculatum and its effect of apoptosis induction in tumor cells.Methods CA was evaluated for its cytotoxicity in vitro against MCF-7,BEL-7402,and HO-8910 cells by determining MTT assay and its antitumor effects in vivo on S180 tumor-bearing mice by calculating tumor-inhibited rate.Measures of apoptosis including Wright′s-Giemsa staining and flow cytometry(FCM) assay were involved to explore the mechanism.And the toxcity of CA on normal cells was also evaluated on in vitro cultured rat cortical neurons.Results CA showed a definite cytotoxicity to three tumor cell lines with IC50 in the range of 35.68—39.78 mg/L.And it significantly inhibited the tumor growth of S180 tumor-bearing mice at the dose of 40,50,and 160 mg/kg by ig administrated,the inhibitory rates were 20.0%,28.0%,and 48.1%,respectively.At the concentration of 80 mg/L,CA induced obvious apoptosis in MCF-7 cells(P0.01) associated with marked morphological changes such as cytoplasm contraction and nuclear chromatin condensation,while it showed no toxcity to rat cortical neurons cultured 8 d in vitro at the concentration of 100 mg/L.Conclusion CA has significant antitumor effect in vitro[WTBZ] and in vivo,and has moderate effect of inducing tumor cells apoptosis,which may be one of the mechanisms of CA antitumor activity.