Downregulation of PRAME Suppresses Proliferation and Promotes Apoptosis in Hepatocellular Carcinoma Through the Activation of P53 Mediated Pathway.

BACKGROUND/AIMS: The expression of PRAME and its role in hepatocellular carcinoma (HCC) remain unknown. The aim of this study was to examine the functional role of PRAME in HCC development and exploring the molecular mechanism.

METHODS

We first detected PRAME expression in 96 human HCC tissue samples and correlated with clinicopathological characteristics and prognosis of the patients. We then established stable HCC cell lines with PRAME overexpression and knockdown followed by functional analysis in vitro. Further, we examined the relationship between PRAME and p53 pathway in vitro by using Western blotting. Finally, PRAME expression was detected to evaluate its correlation with p-p53 and p53 pathway related apoptotic proteins in xenograft tumor mouse model using immunohistochemistry.

RESULTS

PRAME expression was significantly higher in HCC tissues than in adjacent non-tumor tissues and their expression was positively correlated with alpha fetoprotein levels and tumor size. In addition, PRAME expression was associated with AJCC stage and is a potential biomarker of poor prognosis regarding 5-year overall survival in HCC. In vitro studies, we found that PRAME expression was higher in HCC cell lines than in normal hepatic cell line. Inhibited cell proliferation and increased cell apoptosis was observed in PRAME knockdown HCC cells. Futher, increased cell apoptosis was correlated with the proportion of cells in G0/G1 stage, activated p53 mediated apoptosis, and increased cyclin p21 expression. Xenograft analysis in nude mice also found that PRAME knockdown inhibited tumorigenesis while PRAME overexpression had opposite effect.

CONCLUSIONS

In HCC, PRAME serves as a potential biomarker for poor prognosis and novel therapeutic target in treating this cancer. PRAME is a potential biomarker of poor prognosis in HCC. PRAME surpresses HCC cell death in vitro and in vivo by regulating p53 apoptotic signaling and may serve as a potential therapeutic target in HCC.