肝细胞肝癌和正常肝细胞间隙连接蛋白ConneXin32,ConneXin43蛋白质酪氨酸磷酸化分析

目的：研究肝细胞肝癌和正常肝细胞间隙连接蛋白Cx32,Cx43酪氨酸磷酸化作用的信号转导机制，及其对肝癌的重要意义。方法：应用细胞培养，Western blot分析技术，研究肝癌细胞系HHCC，SMMC－7721和正常肝细胞系QZG中，间隙连接蛋白Cx32,Cx43的表达及酪氨酸磷酸化作用。结果：Western blot分析表明，Cx32蛋白在正常肝细胞系QZG细胞中高表达，但未出现酪化作用。结果：Western blot分析表明，Cx32蛋白在正常肝细胞系QZG细胞中高表达，但未出现酪氨酸磷酸化作用，Cx32蛋白在HHCC，SMMC－7721无明显表达及酪氨酸磷酸化作用，Cx43蛋白在QZG，SMMC－7721细胞一定水平的表达仅在SMMC－7721细胞表现出酪氨酸磷酸化现象，在QZG细胞中无酪氨酸磷酸化作用，Cx43蛋白在HHCC细胞中无明显表达及酪氨酸酸化现象，结论：肝癌细胞Cx32,Cx43蛋白翻译后水平酪氨酸位点磷酸化修饰作用，是调控间隙连接通讯功能的关键，间隙连接基因connexin32,connexin43翻译后水平调节和信号转导机制异常可能与肝癌的发生密切相关。

Phosphorylation on tyrosine of gap junction proteins Cx32 and Cx43 in human hepatocellular carcinoma cell lines

Objective To investigate phosphorylation on tyrosine of gap junction proteins Cx32 and Cx43 and their roles in signal transduction in human HCC cell lines. Methods Human HCC cell lines HHCC, SMMC 7721 and normal liver cell line QZG were cultured. Western blot was employed to analyze phosporylation on tyrosine of Cx32 and Cx43 proteins. Results Western blot showed that gap junction protein Cx32 had high level expressions in normal liver cell line QZG with unphosphorylated tyrosine. Cx32 had very low expression in HCC cell lines of HHCC, SMMC 7721 without phosphorylated tyrosine of Cx32. Both QZG and SMMC 7221 cell lines expressed Cx43 and only SMMC 7221 cells showed phosphorylated tyrosine of Cx43. Conclusions The carcinogenesis of human HCC might be closely related to the abnormal expression of gap junction genes Cx32 and Cx43 as well as disorder of signal transduction.