Targeting MED8 enhances sorafenib sensitivity in hepatocellular carcinoma by disrupting epithelial–mesenchymal transition mechanisms

HCC is a highly lethal cancer characterised by significant sorafenib resistance, leading to poor patient outcomes. Recent studies have suggested that MED8 plays a role in enhancing tumour resistance to drugs, but its role in drug resistance in HCC has not yet been reported. This study found significantly higher MED8 expression in HCC tissues compared to adjacent noncancerous tissues. Increased MED8 expression in HCC correlates with poorer overall survival. Functional assays demonstrated that reduced MED8 expression inhibited HCC cell proliferation and epithelial–mesenchymal transition, promoted apoptosis, and increased sensitivity to sorafenib. Overexpression of MED8 elevated TRIP4 protein levels. TRIP4 overexpression negated the effects of MED8 knockdown, whereas TRIP4 suppression inhibited MED8-driven EMT. Mechanistically, MED8 interacts with TRIP4, reducing its ubiquitination and stabilising TRIP4 protein levels. Our findings indicate that the MED8–TRIP4 axis plays a role in sorafenib resistance in HCC and could serve as a therapeutic target for HCC treatment. Elevated MED8 is closely associated with sorafenib resistance in HCC cells. MED8 contributes to sorafenib resistance of HCC by enhancing TRIP4-mediated EMT. MED8 interacts with TRIP4’s N-terminal (aa 1–150) and C-terminal (aa 301–581) domains.