CDCA2 triggers in vivo and in vitro proliferation of hepatocellular carcinoma by activating the AKT/CCND1 signaling

Purpose This study aims to elucidate the biological functions of CDCA2 (cell division cycle associated 2) in hepatocellular carcinoma (HCC) progression and the potential mechanism. Methods CDCA2 levels in HCC tissues and cell lines were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The relationship between CDCA2 and clinical characteristics in HCC patients was analyzed. Cox proportional-hazards model was applied for assessing the potential factors influencing overall survival in HCC. Three CDCA2 siRNAs were generated and the most effective one was used in the following experiments. After knockdown of CDCA2 in HCC-LM3 cells, clonality and viability were examined. Meanwhile, cell cycle progression was detected by flow cytometry. Relative levels of CDCA2, p21, p27, CDK2, CCND1, CCNE1 and CCNB1 in HCC-LM3 cells were determined by qRT-PCR. The activation of the protein kinase B (Akt) signaling was examined by Western blot. Subsequently, we constructed HCC xenograft model in nude mice. Tumor volume and tumor weight of xenografted HCC were recorded. Results CDCA2 was upregulated in HCC tissues than that of para-tumor ones, especially HCC tissues with larger than 5 cm in tumor size or vascular invasion. CDCA2 level was related to tumor size, vascular invasion and tumor differentiation in HCC. Knockdown of CDCA2 inhibited clonality and viability in HCC-LM3 cells, and arrested cell cycle progression in G1 phase via downregulating CCND1. The phosphatidilinositol 3-kinase (PI3K)/Akt was activated by CDCA2 during the progression of HCC. Tumor volume and tumor weight of xenografted HCC decreased in nude mice with in vivo knockdown of CDCA2. Conclusions CDCA2 triggers proliferative potential in HCC by targeting CCND1 via activating the PI3K/Akt signaling.