Studies On The Correlation Between Kinesin Superfamily Protein KIF3B And Hepatocellular Carcinoma

Objective To investigate the expression of KIF3 B in the hepatocellular carcinoma(HCC), and analyze the role of KIF3 B during the cell proliferation process, as well as the molecular mechanism of proliferation.Methods 1. The expression of KIF3 B in 8 cases of fresh frozen specimens from HCC and the adjacent non-tumorous tissues were detected by Western blot. Immunohistochemistry were used to measure the expression of KIF3 B and Ki67(the proliferation index) protein in HCC and adjacent non-tumorous tissues in 57 patients. To analyze the connection between KIF3 B and clinicopathologic datas of HCC patients, such as age、gender、histological differentiation、tumor size、metastasis、the level of AFP and so on. 57 cases of HCC patients were followed up, the 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. HepG2 cells were treated with serum starvation and release for synchronization purpose, the distribution of Hep G2 cell cycle was detected by flow cytometer, then detect the expression variation of KIF3 B during the proliferation of HepG2 cell by western blot.DNA-based small interfering RNA(siRNA) targeting KIF3 B wastransiently transfected, detected the proliferation and cell cycle distribution of HepG2 cells by the Cell Counting Kit-8(CCK8) and FACS and analyzed the expression of cell cycle proteins by Western blotting.Results 1. Western blot and Immunohistochemistry analysis showed that KIF3 B protein level was increased in HCC tissues compared with the adjacent non-tumorous tissues. KIF3 B expression was significantly associated with histological differentiation(p<0.001), tumor size(p=0.002), the level of alpha fetal protein(AFP)(p=0.041). Correlation analysis showed that KIF3 B expression was positively associated with Ki67(r2=0.436;p<0.001).The Kaplan-Meier survival curves showed that the high expression of KIF3 B related to a poor survival with statistical significance(p<0.01). Unvaried analysis showed that KIF3 B expression was associated with the poor prognosis of HCC( p<0.010). Multivariate Cox proportional hazards regression analysis showed that KIF3 B expression was an independent prognostic marker for HCC( p<0.001).2. The cell cycle of HepG2 was blocked by serum starvation.The expression of KIF3 B, cyclinA and CDK2 were down-regulated.The expression of p27Kip1 was increased. siRNA analysis suggeseted that suppression of KIF3 B could inhibit cell proliferation and cell cycle arrest, and the expression of cyclinA, PCNA, CDK2 were down-regulated, the expression of p27Kip1 was up-regulated.Furthermore, suppression of KIF3 B not only decreased cancer cell growth but also induced apoptosis of cells.Conclusions 1. The expression of KIF3 B was upregulated significantly in HCC tumor tissues, and an increased KIF3 B expression was associated with poor overall survival. KIF3 B over-expression is involved in the pathogenesis of hepatocellular carcinoma and may serve as a potential therapeutic target for humanHCC.2. During the proliferation process of HepG2 cells, the expression of KIF3 B was up-regulated. KIF3 B may affected the expression of cyclinA、CDK2 and p27Kip1 in HCC cells, and then the cell cycle was put forward.