Suppression of CUGBP1 inhibits growth of hepatocellular carcinoma cells.

ABSTRACT

PURPOSE: The multifunctional RNA-binding protein, CUGBP1, regulates splicing, stability and translation of mRNAs. Previous studies have shown that CUGBP1 is expressed at high levels in the liver, although its role in hepatocellular carcinoma is unknown. Our aim was to determine if CUGBP1 could regulate hepatocellular carcinoma growth. METHODS: Expression levels of CUGBP1 were analyzed in 70 hepatic carcinoma and 20 normal hepatic tissue samples by immunohistochemistry (IHC). Using lentivirus-mediated short hairpin RNA (shRNA), CUGBP1 expression in human hepatocellular carcinoma HepG2 cells was knocked-down. The effect of CUGBP1 on hepatic cancer cell growth was investigated. RESULTS: CUGBP1 was expressed in 85.7% hepatocellular carcinoma specimens compared with 50% in normal liver specimens. CUGBP1 silencing remarkably decreased the proliferation of HepG2 cells, as determined by MTT assay. Flow cytometry analysis showed that knock-down of CUGBP1 led to G0/G1 phase cell cycle arrest, accompanied by sub-G1 accumulation. Moreover, depletion of CUGBP1 resulted in downregulation of cyclin B1 and upregulation of cyclin D1. CONCLUSION: These results suggest that CUGBP1 is essential for the growth of hepatocellular carcinoma cells. Knockdown of CUGBP1 might be a potential therapeutic approach for human hepatocellular carcinoma.