ABSTRACT
OBJECTIVE: This study aims to investigate the effect of different concentrations of docosahexaenoic acid (DHA) on proliferation and apoptosis in HepG2 cell lines, and to research the possible molecular mechanisms. METHODS: DHA concentration was 0 g/mL in the negative control group, and 15, 30, 45, 60 and 75 ug/mL, respectively, in the experimental groups. CCK-8 and flow cytometry methods were used to observe the growth inhibition and apoptosis rates of HepG2 cells cultured in vitro, which were treated with different concentrations of DHA. The level of ß-catenin and c-myc mRNA and protein were measured by real-time PCR and western blot, respectively. RESULTS: In the concentration range of 0-45 ug/mL, the action time was 24 hours. DHA could inhibit the growth of HepG2 cells, and there were significant differences between the experimental and control groups (P<0.01). The same was observed in each of the two groups in experimental groups. As drug concentration or action time increased, results revealed no statistical differences. Furthermore, flow cytometric analysis indicated that DHA could promote HepG2 cell apoptosis; and the apoptosis rate was greatly different between the experimental and control groups (P<0.01). The same was observed in each of the two groups in the experimental groups. Real-time PCR could detect low c-myc expression in HepG2 cells disposed by DHA, and c-myc expression was significantly different between the experimental and control groups (P<0.01). The same was observed in each of the two groups in the experimental groups. There was no obvious difference in ß-catenin expression between the experimental and control groups, and the experimental groups were all identical. Western blot demonstrated that DHA could decrease ß-catenin and c-myc protein expression in HepG2 cells. CONCLUSION: DHA could promote apoptosis and inhibit the proliferation of HepG2 cells. The possible mechanism was related with the down-regulated protein expression of ß-catenin and the mRNA expression of c-myc.
