Cytoskeleton-Associated Membrane Protein4as A Tumor Suppressor Highly Expressed In Hepatocellular Carcinoma And Predicted Patients Outcome After Surgery Resection

BACKGROUND AND AIMS: CKAP4, also known as P63with molecular weight63KD,one kind of type II trans-membrane protein, located in the endoplasmic reticulum. Earlystudies have shown that CKAP4plays an important role to maintain endoplasmic reticulumstructure. Recently, it has been shown the functions of CKAP4are related to theprogression of carcinoma. So, in this study, we investigated its expression, clinicalsignificance and role in hepatocellular carcinoma (HCC).METHODS: we analyzed the expression of CKAP4by quantitative real-time polymerasechain reaction (RT-PCR), western blot and immunohistochemistry (IHC) in286HCC tissuesamples. The correlation between CKAP4expression and clinicopathological factors wereinvestigated. Survival curves were calculated using the Kaplan-Meier method andcompared by the log-rank test. The Cox proportional-hazard regression model was used foranalyses to explore the effect of the clinicopathological variables and CKAP4expressionon survival. The effects of high expression levels of CKAP4on HCC cells were determinedusing CCK-8, transwell, pharmacologic approaches and mice model. And then weexamined the CKAP4serum concentration in the healthy, hepatitis, cirrhosis and livecancer by enzyme linked immunosorbent assay (ELISA).RESULTS: The CKAP4mRNA and protein levels were much higher in HCC tumor tissues than that in para-tumors or normal liver specimens. IHC in TMA assay showed that theexpression of CKAP4was significantly correlated with tumor size (p=0.001), intra-hepaticmetastases (p=0.005), portal venous invasion (p=0.007) and BCLC stage (p=0.037). Insurvival analysis, HCC patients with high CKAP4expression have a favorable overallsurvival (OS) prognosis and a longer Disease-free survival (DFS) than those with lowerexpression. In multivariate analysis, CKAP4expression was found to be an independentprognostic factor of OS. HCC cells with high CKAP4levels were associated with lowproliferation capability as well as low invasion potential, whose mechanism could berelated to the wnt signaling pathway and epithelial-mesenchymal transition (EMT).Furthermore, we confirmed that the expression of CKAP4could repress the growth oftumor in mice models. The ELISA results shown that CKAP4concentration was higher inthe serum of HCC patients compared with healthy.CONCLUSION: CKAP4expression were up-regulated in HCC and the high level ofCKAP4correlated with favorable prognosis of patients with HCC. Overexpression ofCKAP4represses the proliferation and invasion of HCC cells in vitro and in vivo. Thus, ourresults suggest CKAP4correlated with progression and metastasis of HCC and it serve as anovel prognostic and serum diagnostic marker for patients with HCC.