Synergistic anti-proliferation effect of aspirin and 5-fluorouracil on colon cancer cells and its mechanism

AIM：To investigate the synergistic anti-proliferation effect of aspirin and 5-fluorouracil on the colon cancer cells and its mechanism. METHODS：Colon cancer cells were divided into 4 groups: control group, aspirin group, 5-fluorouracil group and aspirin+5-fluorouracil group. Synergistic anti-proliferation effect of aspirin and 5-fluorouracil on the colon cancer cells was observed by MTT assay. Apoptosis-inducing effect and mechanism were detected by Hoechst 33258 staining, caspase activity assay and flow cytometry analysis. The mRNA and protein levels of apoptosis-related proteins were evaluated by real-time PCR and Western blotting. RESULTS：5-Fluorouracil inhibited proliferation of HCT116 and SW620 colon cancer cells effectively, and low concentration of aspirin exerted synergistic inhibitory effect. 5-Fluorouracil induced apoptotic morphology and increased caspase activity and sub-G1 phase in HCT116 cells. The synergistic effect of aspirin obviously enhanced apoptotic ratio and caspase activity. Moreover, 5-fluorouracil inhibited the mRNA and protein expression of Bcl-2, which was amplified by low concentration of aspirin. CONCLUSION：Aspirin and 5-fluorouracil had a synergistic anti-proliferation effect on the colon cancer cells through apoptosis pathway.