Studies On The Correlation Between Early Mitotic Inhibitor1and Hepatocellular Carcinoma

ObjectiveTo investigate the expression of Early mitotic inhibitor-1(Emil) as cell cycle protein in the hepatocellular carcinoma (HCC), and investigate the role of Emil during the cell proliferation process, as well as the molecular mechanism of proliferation.Methods1. The expression of Emil in8cases of fresh frozen specimens from HCC and the adjacent liver tissue were detected by western blot. Immunohistochemical to detect the expression of Emil and Ki-67(the proliferation index) in114samples of HCC tissue and adjacent non-tumor tissue. To analyze the connection between Emil and clinicopathologic datas of HCC patients, such as age, gender, histological grade, metastasis, the serum of AFP and so on.114cases of HCC patients were followed up, survival curve was calculated using the Kaplan-Meier method, and the prognosis was analyzed with the univariate and multivariate Cox proportional hazards regression analysis.2. HuH7、SMMC-7721cells were treated with serum starvation and release for synchronization purpose, the distribution of HuH7, SMMC-7721cell cycle was detected by flow cytometer, then detect the expression variation of Emil during the proliferation of HuH7, SMMC-7721cell by western blot. HepG2, SMMC-7721 cells were treated with siRNA and overexpression respectively, the distribution of HepG2, SMMC-7721cell cycle was detected by flow cytometer, cell proliferation was detected by CCK-8, then detect the expression variation of Emil and related proteins by western blot.Results1. Immunohistochemistry and western blot analysis showed that Emil expression in HCC were higher than that in non-tumor liver tissue. Emil expression was correlated with histological grade (p=0.001, tumor stage (p=0.002). Correlation analysis showed Emil expression was positively associated with Ki-67(r=0.22; p<0.01).The Kaplan-Meier survival curves showed that high Emil expression related to a poor survival with statistical significance (p<0.01). Unvaried analysis showed that Emil expression was associated with poor prognosis of HCC (p=0.000). Multivariate Cox proportional hazards regression analysis indicated that Emil expression was an independent prognostic marker for HCC (p=0.030).2. The cell cycle of HuH7, SMMC-7721were blocked by serum starvation. The HuH7, SMMC-7721cells were reentering the cell cycle after serum release and the reverse changes of these proteins were happened. The expression of Emil was up-regulated. siRNA analysis showed that knock down of Emil could inhibit cell proliferation and cell cycle arrest, and the expression of cyclinA, cyclinB, Skp2were down-regulated, the albumen amount of p27kip1was up-regulated. Furthermore, Emil overexpression can promote the S-phase entry and increase SMMC-7721cell proliferation, and the expression of cyclinA, cyclinB, Skp2were up-regulated, the albumen amount of p27kip1was down-regulated.Conclusions1. The expression of Emil was up-regulated significantly in HCC. Emil serve as an independent prognostic marker for HCC. These datas revealed that Emil may play a role in the oncogenesis and development of HCC.2. During the proliferation process of HCC cells, the expression of Emil was up-regulated. Emil may inhibit APC/C activity to contributing to substrates cyclinA, cyclinB, Skp2increase, and then the cell cycle was put forward.