Low level of CENP‐E promotes growth of hepatocellular carcinoma and is associated with adverse clinical features

Background: Human kinesin centromere-associated protein E (CENP-E), a spindle checkpoint protein, has been identified as a tumor suppressor. Although reduced CENP-E expression has been reported in human hepatocellular carcinoma (HCC) tissues, its role in hepatocarcinogenesis is unknown. To-date, there is no evidence linking reduced CENP-E expression to HCC initiation and development or if low CENP-E in HCC has any clinical relevance. In this study, we investigated the contribution of reduced CENP-E on HCC development and the clinical relevance of low CENP-E in HCC patients. Methods: HCC cell lines (SMMC7721 and QGY7701), xenograft animals, and 90 human HCC tissues were used to investigate the importance of CENP-E as a tumour suppressor. CENP-E-was silenced using-shRNAs and validated by western blotting and Immunohistochemistry (IHC). In vitro effects were studied using cell proliferation, migration, colony forming and wound closure assays. Cell cycle and cell apoptosis was analysed by flow cytometry. The in vivo effect of down-regulated CENP-E on tumor growth was examined in a xenograft tumor model. CENP-E expression in HCC tissues was analysed by IHC. Analysis of patient survival was performed using Kaplan–Meier analysis and Cox regression analysis (SPSS). Results: We demonstrated that down-regulation of CENP-E by CENP-E-silencing shRNAs significantly promoted HCC proliferation/growth both in vitro and in vivo. CENP-E suppressed the proliferation of HCC cells by halting cell cycle progression at the G1-S phase and accelerated cell apoptosis. Analyses of HCC patient samples/clinical data revealed that CENP-E was significantly down-regulated in HCC tissues and low CENP-E expression was significantly associated with patient’s adverse clinicopathological features: poor prognosis, advanced TNM stage, metastasis, and larger tumor size. Multivariate analysis indicated that CENP-E was an independent prognostic factor predicting outcomes of advanced HCC patients. Conclusions: Our data suggests that loss of CENP-E contributes to HCC development and is strongly associated with the adverse clinical pathology of HCC. Thus CENP-E could be a novel target for new treatments and a useful prognostic biomarker for HCC patients. Keywords: hepatocellular carcinoma, CENP-E, tumor suppressor, cell cycle, biomarke