Abstract: OBJECTIVE: To separate and extract Arca subcrenata Lischke protein component and investigate its anticancer mechanisms on human breast carcinoma MCF-7 cells in vitro. METHODS: Fresh Arca subcrenata Lischke was used as the raw material to extract its anticancer protein component which was named as NS. The growing changes of cultured MCF-7 cells treated with different concentrations of NS(50,100,200,400μg/mL) were observed under the inverted phase-contrast microscope. The cell and nucleus changes of MCF-7 cells treated with NS 200μg/mL were analyzed by Giemsa staining. Flow cytometry was used to evaluate apoptosis and cell cycle of MCF-7 cells treated with NS. The expressions of apoptosis-and cell cycle-related proteins were analyzed by Western blot. RESULTS: Comparing with negative control group,obvious growth inhibition effects were found in MCF-7 cells treated with different concentrations of NS(50,100,200,400μg/mL)(P<0.05 or P<0.01). The appearance of cultured MCF-7 cells treated with NS 200μg/mL for 12,24 and 48 h were shrinking and falling off from the tissue culture flask in a time-dependent manner after treated with NS for 12 h. The percentage of MCF-7 cells in mitosis phase and the multinuclear or nuclear fragmentation cells were obviously increased. Flow cytometry analysis indicated that apoptotic cell increased and G2-M phase cells accumulated significantly with NS(P<0.01). The apoptosis rate of MCF-7 cells increased in a time-dependent manner. The expression of apoptotic protein procaspase-3 and p53 protein were up-regulated after NS treatment for 6 h. CONCLUSION: Inducing apoptosis and cell cycle arrest in G2-M phase were main mechanisms of Arca subcrenata Lischke anticancer protein component NS cytotoxic activity, and procaspase-3 and p53 signal pathways were upregulated in MCF-7 cells.

Key words: Arca subcrenata Lischke, breast carcinoma, MCF-7 cells, G2-M phase arrest, cell apoptosis