DNMT1 and DNMT3A drive hepatocellular carcinoma progression via epigenetic regulation and are inhibited by 5-azacytidine.

Hepatocellular carcinoma (HCC) is a major global health challenge with limited therapeutic options. This study investigates the roles of DNA (deoxyribonucleic acid) methyltransferase 1 (DNMT1) and DNA methyltransferase 3 alpha (DNMT3A) in the advancement of HCC and evaluates their therapeutic potential. Bioinformatics interrogation using Gene Expression Profiling Interactive Analysis 2 (GEPIA2), Kaplan-Meier Plotter, and cBioPortal revealed pronounced upregulation of DNMT1 and DNMT3A in HCC tissues and cell lines, which was tightly associated with unfavorable clinical outcomes. In vitro assays demonstrated that DNMT1 and DNMT3A regulate cell cycle progression and proliferation, with silencing inducing G0/G1 arrest and reducing cell viability, while overexpression reversed these effects. In vivo, 5-azacytidine (5-AZA), a DNMT inhibitor, significantly suppressed tumor growth in a mouse orthotopic liver tumor model, as evidenced by reduced tumor volume and proliferation markers (Ki67) and increased apoptosis (caspase-3). These findings indicate that DNMT1 and DNMT3A drive hepatocellular carcinoma through epigenetic regulation and are viable prognostic biomarkers. Targeting these enzymes with 5-azacytidine offers a promising therapeutic strategy for hepatocellular carcinoma management.