Tumor-Promoting Effects of Microrna-421/4-Aminobutyrate Aminotransferase Axis in Hepatocellular Carcinoma.

Background: MicroRNA-421 (miR-421) has been implicated in hepatocellular carcinoma (HCC), but its potential mechanism in HCC remains unclear. Objectives: The study aimed to study the potential mechanism of miR-421 in HCC which is necessary. Methods: The downstream target genes of miR-421 were screened in HCC tissues and cells using miDIP, Targetscan, and starBase databases. Differential analysis, survival analysis, and Pearson correlation analysis were performed between miR-421 and its downstream target genes. Quantitative reverse transcription polymerase chain reaction and western blot were used to assay RNA and protein levels of 4-aminobutyrate aminotransferase (ABAT) and epithelial-mesenchymal transition (EMT)-related proteins. Cell-based assays, including CCK-8, wound healing, transwell, flow cytometry, and metabolic measurements, were implemented to assess proliferation, migration, invasion, cell cycle, and apoptosis of HCC cells with different treatments. Dual-luciferase assay was utilized to detect the targeting relationship between miR-421 and ABAT. Results: miR-421 level was elevated in HCC tissues and cells, and low miR-421 expression hindered phenotype progression of HCC cells. ABAT was identified as a direct target of miR-421 in HCC cells, and miR-421 could inhibit ABAT expression. Rescue assay revealed that miR-421 promoted HCC cell tumorigenesis progress and affected cell metabolic remodeling through down-regulating ABAT. Conclusion: The miR-421/ABAT regulatory axis promoted HCC cell tumorigenesis progress, highlighting its potential as a therapeutic target for HCC. (REV INVEST CLIN. 2023;75(5):233-48).