胃癌中连接蛋白32和43的表达及细胞间隙连接通讯功能的研究

目的探讨细胞间隙连接蛋白(Cx)表达及细胞间隙连接通讯(GJIC)功能状况与胃癌发生、发展的关系。方法采用免疫组化和间接免疫荧光法分别检测胃癌组织和不同分化程度的胃癌细胞系中Cx32和Cx43的表达;应用Western blot法检测Cx43在胃癌组织、癌旁组织及不同分化胃癌细胞系中的表达;应用划痕染料示踪技术检测不同细胞系中细胞GJIC功能。结果在正常胃组织中,Cx32和Cx43的阳性表达率均为100.0%,在胃癌组织中Cx32和Cx43的阳性表达率分别为49.5%(55/111)和39.6%(44/111)。Cx32的表达与组织类型、分化程度、远处转移及临床分期有关(P<0.05),而与侵袭程度、年龄无关(P>0.05);Cx43的表达与组织类型、分化程度、远处转移、侵袭程度及临床分期有关(P<0.05),而与年龄无关。Cx32和Cx43在转化的人胃黏膜细胞系GES-1中的阳性表达率均为100.0%;在胃高分化腺癌细胞系N87中的阳性表达率分别为49.0%和55.0%;在胃低分化腺癌细胞系BGG-823中均无表达。GES-1细胞具有强GJIC功能,N87和BGC-823细胞均无GJIC功能。Cx43在胃癌组织中的表达量明显低于癌旁正常组织,在GES-1和N87细胞中的表达水平依次递减,在BGC-823细胞中几乎无表达。结论Cx32和Cx43表达下降与胃癌的发生、发展有关。

Decreased expression of Cx32 and Cx43 and their function of gap junction intercellular communication in gastric cancer

Objective The aim of this study was to investigate the expression of connexin( Cx) and the function of gap junction intercellular communication ( GJIC) in the carcinogenesis, progression and metastasis of gastric cancers. Methods Immunohistochemistry was used to detect the expression of Cx32 and Cx43 proteins in tissue samples. Indirect immunofluorescence assay was used to investigate the expression of Cx32 and Cx43 proteins in several gastric cancer lines of various differentiation grades. The expression of Cx43 in samples of gastric cancer tissue, adjacent normal tissue and in the gastric cancer cell lines of various differentiation grades was detected by Western blot. Scrape-loading dye transfer ( SLDT) technique was used to detect the function of gap junction intercellular communication ( GJIC) in the various cell lines. Results In the normal gastric mucosa the expression rates of both Cx32 and Cx43 were 100%. In gastric cancers, the expression rates of Cx32 andCx43 were 49. 5% (55/111) and 39. 6% (44/111 ) , respectively. There was a significant difference between their expression in normal and cancer tissues (P< 0.05). Age of the patients was not significantly correlated with the expression level of Cx32 and Cx43 ( P > 0.05). Cx43 expression was significantly associated with the TMN stage, histological type, depth of infiltration and distant metastasis (P<0. 05) ,but Cx32 expression was not significantly correlated with depth of infiltration(P>0. 05). In the cancer cell lines, a positive expression of Cx32 and Cx43 was detected in transfected human stomach mucosal cell line(GES-1)and human well differentiated stomach cancer cell line (N87) , but negative in the poorly differentiated stomach cancer cell line ( BGC-823) at all. Both Cx32 and Cx43 expression rates were 100% in the cell line GES-1. Cx32 expression rate was 49. 0% and Cx43 expression rate was 55.0% in the cell line N87. But in the poorly differentiated cancer cell line BGC-823 both Cx32 and Cx43 expression was negative. GJIC function detection showed; GES-1 showed well GIJC function but no GIJC function in the cell lines N87 and BGC-823. The intensity of fluorescence was gradually decreasing from GES-1 cells to N87 cells and almost no fluorescence in BGC-823 cells. Western blotting showed that Cx 43 expression in normal tissue was higher than that in gastric cancer tissue, and in the cell lines GES-1, N87 and BGC-823, the bands seemed decreasing progressively. There was very low expression in BGC-823 cells. Conclusion The decreasing expression of connexin Cx32 and Cx43 is obviously correlated with the occurrence, development and metastatic potential of stomach cancers.