肝癌组织中gp78蛋白与KAI1蛋白的相互关系研究

Relationship between gp78 and KAI1 protein in hepatocellular carcinoma

目的探讨gp78蛋白与肝癌组织中的肿瘤转移抑制基因KAI1蛋白可能存在的相互关系。方法收集肝癌组织30例及与其相对应的癌旁组织标本30例。用MHCC-97肝癌细胞接种裸鼠肝脏,产生肝脏原位肿瘤9例及肿瘤转移灶14例,收集肿瘤组织和正常肝脏组织。采用免疫组织化学和蛋白质印迹技术检测相关组织中gp78蛋白及KAI1蛋白的表达。结果蛋白质印迹结果表明,人肝癌组织中gp78蛋白的表达水平(0.350±0.143)明显高于人癌旁组织(0.036±0.003,P=0.016),而KAI1蛋白的表达水平(0.036±0.008)则明显低于人癌旁组织(1.173±0.124,P=0.003)。与癌旁组织相比,30例肝癌组织中24例(80%)gp78水平升高,20例(66.7%)KAI1水平降低;9例裸鼠肝癌组织中8例(88.9%)gp78水平升高,6例(66.7%)KAI1水平降低;14例肝癌转移灶样本中,12例(85.7%)gp78水平升高,13例(92.8%)KAI1水平降低。免疫组织化学结果显示,30例人肝癌组织中,有22例(73.3%)gp78呈强阳性表达(分值≥5分),19例(63.3%)KAI1阳性表达较低(分值≤2分);9例裸鼠原位肝癌组织gp78阳性表达率均较高(分值≥5分),有7例(77.8%)KAI1阳性表达率较低(分值≤1分);14例裸鼠肝癌转移灶中,有12例(85.7%)gp78阳性率表达增高,11例(78.6%)则表现为KAI1表达降低。结论gp78蛋白和肿瘤转移抑制基因KAI1蛋白在肝癌的发生发展,尤其是肝癌的转移过程中发挥了重要作用。与正常肝癌组织相比,原位肝癌和肝癌转移灶的gp78表达水平升高,而KAI1表达水平降低。gp78的过表达导致肿瘤转移抑制因子KAI1表达水平降低,可能是肝癌转移浸润的机制之一。

Objective To investigate the relationship between ubiquitin ligase gp78 and anti-metastasis gene KAI1 in human and athymic mouse bearing hepatocellular carcinoma.Methods Thirty cases of hepatocellular carcinoma tissues and the corresponding normal liver tissues were collected.The livers of athymic mice were inoculated with MHCC-97 cells to produce 9 hepatocellular carcinoma tissues in situ and 14 metastases of liver cancer.Specimens of both tumor tissues and normal tissue were collected.The levels of gp78 and KAI1 protein were detected with Western blotting and immunohistochemistry.Results The expression of gp78 was remarkably higher in human liver cancer tissues （0.350±0.143） than in the matched normal tissues （0.036±0.003,P=0.016）,while the KAI1 was much lower in human liver cancer tissues （0.036±0.008） than in the matched normal tissues （1.173±0.124,P=0.003）.Compared with the matched normal tissues,24（80.0%）,8（88.9%）,12（85.7%） cases with up-regulated gp78 level,20（66.7%）,6（66.7%）,13（92.8%） cases with down-regulated KAI1 level were found in human liver cancer tissues,the liver cancer tissues of athymic mice and the metastases of liver cancer,respectively.In human liver cancer tissues,there were 22 cases （73.3%） with high positive gp78 expression （value≥5）;19（63.3%） with lower positive KAI1 expression （value≤2）.The positive expression rate was higher in gp78 in all the liver cancer tissues of 9 athymic mice （value≥5）,and lower in KAI1 in 7 cases （77.8%,value≤1）.In 14 metastasis of liver cancer,positive expression rate of gp78 was up-regulated in 12 （85.7%） cases （value≥5）,and KAI1 down-regulated in 11 cases （78.6%,value≤1）.Conclusions gp78 and KAI1 play an important role in the carcinogenesis,development,and metastasis of hepatocellular carcinoma.Detection of the expression of gp78 and KAI1 protein may be useful to predicting the occurrence and development of hepatocellular carcinoma.