Potentiating activities of chrysin in the therapeutic efficacy of 5-fluorouracil in gastric cancer cells

The incidence and mortality rates of gastric cancer rank among the highest five of all cancer types worldwide. The chemotherapeutic agent 5-fluorouracil (5-FU) is the gold standard for treating gastric cancer, but its efficacy is limited due to high rates of resistance. To improve the therapeutic efficacy of 5-FU and overcome its resistance, the synergistic effect of chrysin with 5-FU was investigated and its mechanism was elucidated. Chrysin was co-administered with 5-FU in AGS cells and 5-FU-resistant AGS cells (AGS/FR). Cytotoxicity was investigated using MTT assay, followed by calculating the combination index (CI). Several biomarkers were detected using western blotting analysis. Apoptosis and cell cycle distribution were measured by flow cytometry. The combination of chrysin and 5-FU significantly increased cytotoxicity more than chrysin or 5-FU alone. 5-FU induced apoptosis through p53-p21 activity, while chrysin arrested the cell cycle in the G2/M phase. The combination of chrysin and 5-FU showed an anticancer effect via S phase arrest. The results indicated that chrysin and 5-FU exhibited anticancer properties via different pathways. Furthermore, the present study found that chrysin enhanced the chemotherapeutic effect of 5-FU in AGS/FR cells. In the resistant cells, the combination of chrysin and 5-FU improved the anticancer effect via G2/M phase arrest. These findings indicated that chrysin potentiated the chemotherapeutic effect of 5-FU in gastric cancer AGS and AGS/FR cells via cell cycle arrest. Therefore, chrysin may be used to treat gastric cancers that have become resistant to 5-FU.