Downregulation of Brf1 Induces Liver Failure and Inhibits Hepatocellular Carcinoma Progression by Promoting Apoptosis

The occurrence and development of hepatocellular carcinoma (HCC) are closely related to abnormal apoptosis. Brf1 is highly expressed in HCC and has clinical prognostic value. Here, attenuation of Brf1-induced apoptosis was found, and the related mechanism was explored. In the study, general bioinformatics data for Brf1 were obtained from The Human Protein Atlas (HPA). Analyses of the clinical prognostic value of Brf1 in HCC were performed with the Xiantao Academic web server using R software. The basic data were obtained from the GTEx database and TCGA database. Brf1 conditional knockout mice were obtained by repeated mating of C57BL/6 Brf1LoxP/LoxP and C57BL/6 NS5A-alb-Cre-ERT2 mice and verified by genotyping. Liver function measurements, hematoxylin and eosin staining (HE), and immunohistochemistry (IHC) were performed to explore the cause of mouse death after Brf1 knockout. The Brf1 knockdown HCC cell model was generated using lentiviral vector-based shRNA transduction. Cell proliferation assays, plate colony formation assays, anchorage-independent colony formation assays and mouse subcutaneous tumor models were used to evaluate the progression of HCC. Western blot (WB) analysis, flow cytometry, and TUNEL assays were used to detect apoptosis. DNA sequencing, transcriptomics, and proteomics analyses were carried out to explore the antiapoptotic mechanism of Brf1. We found that Brf1 was highly expressed in HCC and had clinical prognostic value. Brf1 knockout led to liver failure and hepatocyte apoptosis in mice. Downregulation of Brf1 slowed HCC cell proliferation, colony growth, and mouse subcutaneous tumor growth and increased the sensitivity of HCC cells to apoptosis induced by chemotherapy drugs. The expression of Brf1 was positively related to that of the apoptosis gene Bcl-2. The sequencing, transcriptomics and proteomics analyses consistently showed that energy metabolism played an important role in Brf1 function, that protein-protein interaction was the primary mode, and that organelles such as mitochondria were the main sites. In Conclusions, downregulation of Brf1 inhibits HCC development by inducing apoptosis. Energy metabolism plays an important role in Brf1 function. These results provide a scientific basis for combating HCC.