The Function And Mechanism Of MicroRNA-4310 In Lipid Metabolism And Liver Cancer

Hepatocellular carcinoma(HCC)is one of the most malignant tumors with high incidence and mortality.Although great progress has been made in the treatment and diagnosis of HCC,the prognosis of HCC patients is still poor due to the high incidence of recurrence and metastasis.Therefore,it is urgent to develop novel therapeutic targets and strategies for HCC.HCC is usually characterized by reprogrammed lipid metabolism.Compared with normal cells,HCC cells develop increased fatty acid(FA)biosynthesis.Excessive lipids provide material and energy for the rapid proliferation and migration of cancer cells.Abnormal lipid metabolism in tumors is accompanied by the abnormal expression of a series of lipid metabolism enzymes.Therefore,reprogrammed lipid metabolism has been targets for cancer therapy.In this study,we screened the factors regulating lipid metabolism with CRISPR/Cas9 library in HCC cells,and identified micro RNA-4310(mi R-4310)inhibiting lipid synthesis in HCC cell.Further investigation indicated that mi R-4310 was significantly down-regulated in HCC patients,while the key enzymes of lipid sysnthesis SCD1 and FASN were significantly up-regulated in HCC patients.Moreover,the expression of mi R-4310 was negatively correlated with the expression of SCD1 and FASN.Importantly,HCC patients with high expression of mi R-4310 in have longer overall survival,in contrast,HCC patients with high expression of FASN and SCD1 have shorter overall survival.Flow cytometry results showed that mi R-4310 mimics reduced the synthesis of lipid droplets in HCC cells,while inhibiting mi R-4310 increased the synthesis of lipid droplets in HCC cells.mi R-4310 mimics reduced the content of triglycerides and cholesterol in HCC cells,while inhibiting the expression of mi R-4310 increased the content of triglycerides and cholesterol in HCC cells.q RT-PCR assay and Western blot indicated that inhibition of mi R-4310 promoted FASN and SCD1 m RNA and protein levels,and mi R-4310 mimics inhibited FASN and SCD1 m RNA and protein levels.Dual luciferase reporter assay demonstrated that mi R-4310 mimic reduced the activity of SCD1 and FASN wild-type 3’-UTR(untranslated region)dual luciferase reporter activity,but did not affect SCD1 and FASN mutant 3’-UTR dual luciferase activity.mi R-4310 regulated lipid droplet synthesis,triglyceride and cholesterol content of HCC cells by targeting SCD1 and FASN.Furthermore,we found that mi R-4310 regulates the proliferation,migration and invasion of HCC cells by targeting SCD1 and FASN in vitro.With xenograft mouse models and metastatic mouse models,we found that mi R-4310 regulated tumor growth and metastasis in vivo.In summary,our data demonstrated that mi R-4310-FASN/SCD1 axis plays an important role in the development and progression of HCC,and may become potential targets for HCC treatment.