Cordyceps militaris polysaccharide triggers apoptosis and G0/G1 cell arrest in cancer cells

Although many studies have shown the antitumor properties of Cordyceps militaris (artificial cultivated from Bombyx mori pupa) polysaccharides, little is known regarding the mechanism of its effects. This study was conducted to determine the mechanism of antitumor effects of C. militaris polysaccharide extract by evaluating apoptosis rate and cell cycle progression status in human liver cancer cell SMMC-7721, stomach cancer cell BGC-823 and breast cancer cell MCF-7. Results showed that C. militaris polysaccharides inhibited proliferation of SMMC-7721, BGC-823 and MCF-7 cells with an IC50 of 192 ± 23.2 μg/mL, 237 ± 12.7 μg/mL and 165 ± 16.3 μg/mL, respectively. We also found that C. militaris polysaccharides at increasing concentrations induced apoptosis dose dependently in those cancer cells: apoptosis rates were 48.3%, 59.4% and 70.9% for SMMC-7721, 41.3% and 57.0%, 72.2% for BGC-823 and 61.3%, 66.9% and 80.6% for MCF-7 at 110, 156 and 323 mg/mL of C. militaris polysaccharides, respectively. C. militaris polysaccharides arrested SMMC-7721, BGC-823 and MCF-7 cells at G0/G1 and G2/M phases with corresponding decrease in S-phase. This study suggests that C. militaris polysaccharides may exert its antitumor effects in those cancer cells by suppressing its growth, arresting the G0/G1-phase, reducing DNA synthesis and inducing apoptosis.