miR-625-5p overexpression is associated with cholesterol metabolism-related signaling and doxorubicin response in HepG2 cells

Hepatocellular carcinoma (HCC) remains a leading cause of cancer-related mortality, in part because of therapeutic resistance and tumor recurrence. Dysregulated cholesterol metabolism has been linked to cancer stemness, epithelial-mesenchymal transition (EMT), and reduced chemotherapeutic responsiveness in HCC. The role of miR-625-5p in cholesterol metabolism-associated signaling and doxorubicin (DOX) sensitivity remains incompletely defined. This study therefore evaluated the effects of miR-625-5p overexpression on lipid metabolism-associated pathways and DOX responsiveness in the HepG2 cell model. HepG2 cells were transfected with a miR-625-5p expression construct using polyethyleneimine-mediated delivery. Cell viability was assessed by MTT assay, and gene and protein expression were evaluated using quantitative real-time PCR and western blotting. Inflammatory cytokines, oxidative stress markers, apoptosis, and colony-forming ability were also examined after treatment with miR-625-5p and/or DOX. In HepG2 cells, miR-625-5p overexpression was associated with lower transcript levels of cholesterol metabolism-associated and oncogenic regulators, including SOX2, YAP, SREBP2, LDLR, HMGCR, and HDLBP. It was also associated with reduced expression of stemness- and EMT-related markers and with enhanced apoptotic responses. Combined miR-625-5p and DOX treatment altered oxidative stress and NLRP3-associated inflammatory markers and produced the lowest observed mean cell viability and clonogenic survival among the tested groups, although formal pharmacologic synergy was not established. Within the limits of this single-cell-line model, these findings suggest that miR-625-5p overexpression is associated with altered cholesterol metabolism-related and oncogenic signaling and increased DOX responsiveness in HepG2 cells. The study does not establish direct miRNA-target binding, cancer specificity, or generalizability to other HCC models.