Tripartite motif protein 25 (TRIM25) expression was altered in various human cancers. Herein, we found that the expression of TRIM25 was elevated in hepatocellular carcinoma (HCC) tissues and cell lines. Knockdown of TRIM25 increased the sensitivity of HCC HepG2 cells to epirubicin (EPI), as indicated by reduced cell viability, enhanced cell apoptosis, and downregulated P-glycoprotein (P-gp) and multiple drug-resistance protein 1 (MRP1). Moreover, TRIM25 knockdown strengthened the effects of EPI on phosphatase and tensin homolog (PTEN) and phosphorylated (p)-AKT. However, overexpression of TRIM25 exerted an opposite effect, weakening the sensitivity of Huh7 to EPI, and obviously increasing PTEN and reducing p-AKT. Most important, all the changes induced by TRIM25 overexpression in Huh7 were reversed with additional treatment of LY294002 (an AKT pathway inhibitor). Notably, coimmunoprecipitation experiments confirmed the interaction between TRIM25 and PTEN. Knockdown of TRIM25 resulted in reduced ubiquitination of PTEN protein. Collectively, our data suggested that TRIM25 enhanced EPI resistance via modulating PTEN/AKT pathway, and targeting TRIM25 may enhance the sensitivity of HCC cells toward chemotherapy drugs.
KEYWORDS: AKT pathway, TRIM25, epirubicin, hepatocellular carcinoma