The Effect of Licorice Protein Fractions on Proliferation and Apoptosis of Gastrointestinal Cancer Cell Lines

Abstract

Background: Several methods for the treatment of colon cancer have been introduced, but none of them are safe and effective. We planned to evaluate the inhibitory effect of protein extract of licorice root on HT-29 and CT26 cell lines proliferation and apoptosis. Methods: Protein extract of licorice root was prepared in phosphate-buffered solution, and SDS-PAGE was used to isolate its fractions. HT-29, CT-26, and HEK293 cell lines were treated with various concentrations of the fractions and full extract of licorice. Cytotoxicity of licorice at various concentrations was assessed using MTT assay. Flow cytometry analysis was applied to evaluate the apoptosis. Results: Our results demonstrated that the concentrations of 5g/mL from 25 to 33kDa fraction and concentration of 8g/mL from 62kDa fraction had a significant inhibitory effect on both cancerous cell lines (P < 0.05), with no significant effect on the noncancerous cell line. The concentrations of 50 and 100g/mL from full extracts significantly increased apoptosis in CT26 cells 35.52 +/- 7.5 (P = 0.048*) and 47.72 +/- 8 (P 0.026*), respectively, but not in HT29 and noncancerous cell lines. Conclusions: Protein compounds of licorice showed anticancer properties and were able to induce apoptosis in both human colon cancer and mouse colon carcinoma cell lines.