The Significance Of The Abnormal Expression Of β-catenin In The Development And Differentiation Of Primary Hepatocellular Carcinoma

Background:The primary hepatocellular carcinoma (HCC) is one of the most common tumors threatening human health. Recently, more and more researches focused on the pathogenesis of HCC. Several studies have showed that abnormal activation of the Wnt pathway was involved in carcinogenesis of several human cancers including HCC. So, the abnormal expression ofβ-catenin, the main factor of the Wnt pathway, may play an important role in the development, differentiation and metastasis of HCC, as well as the development of posthepatitic cirrhosis and HCC origin from liver stem cell. However, the mechanisms involved remained unclear. The abnormal expression ofβ-catenin in HCC had been reported, but it still difficult to explain its relationship with HCC and cirrhosis. The contrasting research among normal liver tissues, cirrhosis and primary hepatocellular carcinoma tissues have not been reported, as well as the relationship of the abnormal expression ofβ-catenin and the especially hepatic construction and mini-environment. For a long time, we believe liver cirrhosis is the precancer of HCC, but there is no direct evidence. In resent years, based on the discovery of liver stem cell (HOC), a kind of unstable and reproducible cell, in HCC and cirrhosis tissues , it is predicated that this kind of cells maybe cause HCC. Several studies focused on histological individual character of HOC, but few on the abnormal expression ofβ-catenin in HOC to reveal the mechanisms of HOC causing HCC. So we tried to demonstrate the mechanisms of the development, differentiation of HCC and the relationship between HCC and HOC, liver cirrhosis through studying the abnormal expression ofβ-catenin in HCC. This study may be useful to the prevention and therapy of HCC.Objective:1. To investigate the abnormal expression of theβ-catenin and its role in the development and differentiation of the primary hepatocellular carcinoma. 2. To explore the mechanisms that the hepatic stem cell causes the primary liver carcinoma.3. To reveal the relationship between the primary liver carcinoma and the cirrhosis.4. To investigate the relationship between the abnormal expression of theβ-catenin and the especially hepatic construction and mini-environment.Materials and Methods:1. Forty samples of primary hepatocellular carcinoma tissues, twenty samples of normal hepatocellular tissues and twenty samples of cirrhosis tissues obtained from patients who underwent liver resection in Daping hospital were analyzed. The tissues were stored at -80℃for immunohistochemistry.2. Immunohistochemistry and Western-blotting technique were used to detect the expression ofβ-catenin in the hepatocellular carcinoma, normal liver and cirrhosis .3. The SMCC,HepG2,L2,WB were bought from The Academy of Military Medical Sciences.4. SMCC,HepG2,L2,WB were cultured in vitro.5. Immunofluorescence technique was carried out to detect WB.6. Immunocytochemistry and Western-blotting technique were performed to detect the expression ofβ-catenin in the SMCC,HepG2,L2 and WB .7. All the data analysis was accomplished using SPSS 10.0 software. Significance was defined as P<0.05.Results1. In normal hepatic tissues,β-catenin was detected in the cell membrane. Neither cytoplasm nor nuclear expression could be observed. The overexpression rate ofβ-catenin in the cytoplasm was 65 % (26/40) in primary hepatocellular cancer tissues while 45 % (9/20) in hepatitis cirrhosis tissues. The reduced membranous expression rate was 77.5% (31/40) in primary hepatocellular cancer tissues while 20 %( 4/20) in hepatitis cirrhosis tissues. This study showed that there isβ-catenin relocation from the membrane to the cytoplasm. Western-blotting technique revealed thatβ-catenin accumulated in the cytoplasm and nuclear of hepatic carcinoma tissues.2.The degree ofβ-catenin relocation from the membrane to the cytoplasm in the poorly differentiated HCC is greater than in the moderately and well-differentiated HCC. The degree ofβ-catenin relocation is greater in the moderately HCC than in the well- differentiated HCC.3. WB with c-kit antibody was found using Immunofluorescence technique.4.The degree ofβ-catenin relocation from the membrane to the cytoplasm in HepG2 and SMCC is greater than in WB and L2 cell lines.β-catenin was found to be accumulated in cytoplasm and in nuclear of HCC, HepG2 and SMCC, but not in L2 and normal liver tissues, and its degree is greater than that in WB and hepatitis cirrhosis tissues.Conclusion1.The abnormal expression ofβ-catenin in the cell membrane , cytoplasm and nuclear were found in the primary hepatocellular carcinoma. And this abnormal expression might play a pivotal role in development of primary hepatocellular carcinoma.2.The liver cirrhosis may be the precancer of HCC3.The abnormal expression ofβ-catenin may be involved in the differentiation of HCC.4.The abnormal expression ofβ-catenin may be independence with especially hepatic construction and mini-environment.5.This investigation would support the primary hepatocellular carcinoma to originate from HOC.