中文摘要：

目的探讨乳腺癌细胞Hs578T中缝隙连接蛋白43（connexin43,Cx43）的表达,以及由其形成的缝隙连接（gapjunction,GJ）对阿霉素（adriamycin,ADM）细胞毒性的影响。方法采用Western blot检测Hs578T细胞中Cx43表达水平;细胞免疫荧光法观察Hs578T细胞膜Cx43蛋白的表达;细胞接种荧光示踪法测定Hs578T细胞荧光传递功能;MTT法检测缝隙连接功能对ADM细胞毒性的影响。结果Hs578T细胞中天然表达Cx43,10μmol·L-1维甲酸（ratinoicacid,RA）处理细胞24 h后,细胞中Cx43蛋白表达水平增高,25μmol·L-1 oleamide和10μmol·L-118-α-GA分别处理细胞24 h后,细胞中Cx43蛋白表达水平降低;Hs578T细胞膜表面有Cx43蛋白表达;10μmol·L-1RA预处理细胞24 h,细胞间荧光传递功能增强（P〈0.01）,25μmol·L-1oleamide和10μmol·L-118-α-GA预处理细胞1 h,细胞间荧光传递功能降低（P〈0.01）;在高密度接种细胞（生长融合,有GJ形成）,10μmol·L-1RA增强细胞GJ功能,6μmol·L-1ADM对细胞增殖抑制率明显增加（P〈0.01）,25μmol·L-1 oleamide或10μmol·L-1 18-α-GA抑制细胞GJ功能,6μmol·L-1ADM对细胞增殖抑制率降低（P〈0.01）,而在低密度接种细胞（生长未融合,无GJ形成）细胞增殖抑制率没有改变（P〉0.05）。结论 Hs578T细胞天然表达Cx43蛋白,并且增强细胞间由Cx43形成的GJ功能,ADM的细胞毒性也增加;而抑制细胞GJ功能时,ADM的细胞毒性也相应降低。

英文摘要：

Aim To investigate the expression of Cx43 in breast cancer cell Hs578T,and the influence of gap junction composed of Cx43 on the cytotoxicity of ADM.Methods Immunofluorescence assay was used to detect the expression of Cx43 in Hs578T.Parachute assay was used to detect the function of gap junctions in Hs578T cell lines.MTT assay was used to dectect the surviving fraction of Hs578T cells treated with ADM.Results Western blot confirmed that Cx43 was expressed in breast cancer cells Hs578T naturally.Compared with control group,the Cx43 expression was increased in cells treated with 10 μmol·L-1 RA for 24 h, while the Cx43 expression was decreased in different levels in cells treated with 25 μmol·L-1 oleamide and 10 μmol·L-1 18-α-GA for 24 h respectively.The intercellular dye coupling through gap junction composed of Cx43 was increased when the cells were exposed to 10 μmol·L-1 RA（P0.01） and were obviously decreased when exposed to 25 μmol·L-1 oleamide and 10 μmol·L-1 18-α-GA（P0.01）.The results of MTT showed that at high density（confluent,GJ formed）,pretreated cells with RA,the cytotoxicity of ADM was increased（P0.01）;when pretreated cells with oleamide and 18-α-GA,the cytotoxicity of ADM was decreased.However,at low density（preconfluent,no GJ formed）,RA,oleamide and 18-α-GA had no effect on the surviving fracion treated with ADM,compared with ADM only（P0.05）.Conclusions Cx43 is expressed in breast cancer cell Hs578T naturally.The enhancement of gap junction function increases ADM cytotoxicity on Hs578T cells,while the inhibition of gap junction composed of Cx43 reduces ADM cytotoxicity on Hs578T cells.