LRP16基因通过雌激素受体α介导抑制Ishikawa细胞中E-钙黏着素的转录活性

LRP16 Gene Suppresses the Transcriptional Activity of E-Cadherin Through Estrogen Receptor α Mediation in Ishikawa Cells

目的:既往研究表明LRP16基因过表达通过下调E-钙黏着素促进子宫内膜癌Ishikawa细胞的侵袭生长,本研究目的在于探讨LRP16基因下调E-钙黏着素的分子途径。方法:用免疫组化方法检测LRP16基因过表达的Ishikawa细胞中E-钙黏着素的表达;用共转染与荧光素酶实验检测LRP16基因对E-钙黏着素启动子转录活性的影响;用染色质免疫共沉淀实验检测雌激素受体α(ERα)与LRP16蛋白在E-钙黏着素启动子区的招募状况。结果:E-钙黏着素在LRP16过表达的Ishikawa细胞中的表达水平明显下调;LRP16抑制了E-钙黏着素启动子的转录活性,该效应呈现对雌激素(E2)存在的依赖性特征;LRP16本身没有与E-钙黏着素启动子区结合,但明显抑制了ERα与E-钙黏着素启动子区的结合。结论:LRP16通过抑制ERα对E-钙黏着素基因的转录激活活性,下调E-钙黏着素在Ishikawa细胞中的表达水平。

Objective： It has been previously demonstrated that the ectopic expression of LRP16 gene in Ishikawa human endometrial cancer cells promoted the invasive ability of the cells through down-regulation of E-cahderin. In this study, the involved molecular pathway was investigated. Methods： The expression of E-cadherin protein in LRP16-overexpressed Ishikawa cells was measured by immunohistological staining. Cotransfection and luciferase assays were used to determine the effect of LRP16 on the transcriptional activity of E-cadherin promoter. The recruitment of both estrogen receptor a（ERα） and LRP16 proteins was detected by chromatin immunoprecipitation（ChIP） assay. Results： E-cadherin was significantly down-regulated in Ishikawa cells with LRP16 overexpression. LRP16 inhibited the transactivation of E-cadherin promoter in an estrogen dependent manner. The recruitment of ERa at the E-cadherin promoter was inhibited by LRP16. Conclusion： LRP16 suppressed the transcriptional activity of E-cadherin in Ishikawa cells through blocking the recruitment of ERa to its promoter region.