Studies On The Correlation Between GART And Human Hepatocellular Carcinoma

Objective1. To investigate the expression of GART in human hepatocellular carcinoma(HCC), and analyze the correlation of abnormal GART expression and the occurrence and development of HCC.2. To investigate the expression variation of GART during the proliferation process of hepatocellular carcinoma cell line Hep G2 and BEL-7404 cells by serum starvation and release experiment,and investigate the role of GART during the process. To futher reveal the molecular pathogenesis of HCC, and hope to provide the new target for therapy of HCC.Methods1. In tissue level, the expression of GART in 8 cases of fresh frozen specimens from HCC and the adjacent liver tissue were detected by Western blot. The expressions of GART and Ki-67(the proliferation index) were detected immunohistochemically in 96 samples of HCC tissues and adjacent non-tumor tissues. The correlation between GART and clinicopathologic datas of HCC was analyzed, including age, gender, histological grade, metastasis,tumor size, serum AFP levels, cirrhosis and vassel invasion.Ninty-six cases of HCC patients were followed up and the survivalcurve was calculated using the Kaplan-Meier method. The prognosis was analyzed with the univariate and multivariate Cox proportional hazards regression analysis.2. Hep G2 and BEL-7404 cells were treated with serum sarvationa and release for synchronization and the cell cycles were detected by flow cytometer. Western blot was performed to detect the expression variation of GART, cyclin A and cyclin D1 in Hep G2 and BEL-7404 cells during serum starvation and release process. After GART expression was down-regulated by transfected with si GART,cell cycle was detected by cytometer and Western blot was used to detect the expressions of GART and PCNA.Results1. Immunohistochemistry and Western blot analysis showed that GART expression in HCC were higher than that in non-tumor liver tissues. GART expression was correlated with histological grade(P=0.001), tumor size(P=0.043), No.of tumor nodes(P=0.020)and metastasis( P=0.031). Correlation analysis showed GART expression was positively associated with Ki-67(γ2=0.443; P<0.01).The Kaplan-Meier survival curves showed that high GART expression related to a poor survival with statistical significance(P=0.002). Univariate analysis showed that GART expression was associated with poor prognosis of HCC(P=0.001). Multivariate Cox proportional hazards regression analysis indicated that GART expression was an independent prognostic marker for HCC(P=0.002).2. The cell cycle of Hep G2 and BEL-7404 was blocked by serum starvation with the down-expression of GART. Meanwhile, the expressions of cyclin A and cyclin D1 were simultaneously down-regulated. The Hep G2 and BEL-7404 cells reentered the cell cycle after serum release and the reverse changes of these proteins were observed. We found that down-expression of GART bytransfected with si GART inhibited proliferation in Hep G2 and BEL-7404 cells.Conclusions1. The expression of GART was upregulated significantly in HCC.GART serve as an independent prognostic marker for HCC. These datas suggested that GART may play a role in the oncogenesis and development of HCC.2. During the proliferation process of Hep G2 and BEL-7404 cells,the expression of GART was up-regulated. After GART was down-regulated the growth of hapatoma cells was inhibited,suggesting that GART may influence the HCC cell cycle progress and proliferation.