Connexin43在肝细胞癌组织中的表达

目的 探讨缝隙连接蛋白（connexin, Cx）43在肝细胞癌（hepatocellular carcinoma, HCC）中的表达和功能。方法 采用免疫组织化学法检测Cx43在20例正常肝脏组织及76例HCC组织中的表达及分布。采用RT-PCR和Western blot法检测正常肝细胞LO2和肝癌细胞SMMC-7721中Cx43的表达,免疫荧光法观察Cx43的分布,细胞接种荧光示踪法测定细胞缝隙连接（gap junction, GJ）功能。结果 Cx43在HCC组织中的阳性表达率较正常肝脏组织明显下调,且从细胞膜向细胞质定位的“内化”现象明显。体外实验进一步证实与LO2细胞相比,Cx43在SMMC-7721细胞上存在表达及分布的异常,并且功能性GJ明显下调。结论 Cx43蛋白数量改变及分布异常与HCC发生密切相关,Cx43有望成为治疗HCC新靶点。

Expression of Connexin43 in Human Hepatocellular Carcinoma Tissues

Objective To investigate the expression and function of connexin 43 (Cx43) in hepatocellular carcinoma (HCC) tissues. Methods The expression and distribution of Cx43 in 20 cases of normal liver tissues and 76 cases of HCC tissues were detected by immunohistochemical method. RT-PCR and Western blot analysis were conducted to detect the expression of Cx43 in normal hepatic cell line LO2 and HCCcell line SMMC-7721, immunofluorescence was further performed to determine the distribution of Cx43,and dye transfer assay was finally used to measure the gap junction (GJ) function between adjacent cells. Results The positive expression rate of Cx43 in HCC tissues was significantly lower than that in normal liver tissues, and a marked "internalization" phenomenon characterized by a distinct Cx43 removal from cell membrane to cytoplasm was also observed. In vitro experiments, an aberrant expression of both amount and distribution of Cx43 in SMMC-7721 cell line was confirmed when compared with those in LO2 cell line. The remnant small amount of Cx43 on the cell membrane of SMMC-7721 cell line formed decreased functional GJs, which was evidenced by dye transfer assay. Conclusion The aberrant expression and localization of Cx43 protein are closely associated with hepatocarcinogenesis, thus Cx43 might be used as a potent and novel therapeutic target for the treatment of HCC.