Combined Effect of Sodium Selenite and Ginsenoside Rh2 on HCT116 Human Colorectal Carcinoma Cells

BACKGROUND: Sodium selenite and ginsenoside Rh2 (G-Rh2) are well known for their anticancer properties and have been exploited as a new therapeutic approach. In this study, we are interested to evaluate if sodium selenite and G-Rh2 combination results in a synergistic anticancer effect that could contribute to lower systemic toxicity. METHODS: We observed the synergistic antitumor effect by combination of sodium selenite and G-Rh2 on HCT-116 human colorectal carcinoma cells in vitro. Cell growth, viability, cell cycle progression and cell apoptosis, Bax/Bcl2 ratio, caspase-3 expression, reactive oxygen species (ROS) production and autophagy were evaluated. RESULTS: The results showed that sodium selenite and G-Rh2 combination have a synergistic effect on cell growth inhibition (57%) compared with sodium selenite (25%) and G-Rh2 alone (28%) after 24hours of treatment. This combination also induced G1 and S phase arrest simultaneously and increased apoptosis rate. The results also indicated that Bax/Bcl2 ratio and caspase-3 expression, known as proapoptotic factors, were increased in the presence of sodium selenite and G-Rh2 alone. However, combined drug treatment results in a more significant increase in Bax/Bcl2 ratio and caspase-3 expression (P < 0.05). In addition, this combination significantly induces a depletion of ROS production and autophagy, compared to control, sodium selenite and G-Rh2 alone (P < 0.05). CONCLUSION: Sodium selenite and ginsenoside Rh2 combination may be a more effective treatment for human colorectal carcinoma and is a promising chemotherapeutic approach for malignant tumors.