BRD4蛋白对乳腺癌细胞上皮-间充质转化的影响及其与患者术后预后的关系

摘要

目的 探讨BRD4蛋白对乳腺癌上皮-间充质转化的影响以及与患者术后预后的关系.方法 采用BRD4短发卡RNA(shRNA)和对照慢病毒感染MCF-7乳腺癌细胞,建立BRD4敲降细胞株(实验组)和对照组细胞株(对照组).采用Western blot分析两组细胞E-钙黏蛋白(E-cad-herin)和波形蛋白(Vimentin)蛋白的表达水平,采用Transwell实验分析对照组和观察组细胞的侵袭能力.收集乳腺癌术后样本,采用免疫组织化学分析肿瘤组织BRD4、E-Cadherin和Vimentin蛋白表达,分析蛋白之间表达的关系与BRD4和患者术后复发的关系.结果 成功建立BRD4敲降细胞株.Western blot分析显示对照组细胞中E-cadherin和Vimentin表达水平(0.57±0.12、0.64±0.18)较观察组(0.26±0.09、0.31±0.08)显著下调,差异有统计学意义(t=3.990、4.109,P＜0.01).对照组细胞侵袭能力(128.43±15.32)明显高于实验组乳腺癌细胞(39.76±9.12),差异有统计学意义(t=3.132,P＜0.01).138例患者其中BRD4高表达高51例,高表达率为36.96％,低表达87例,低表达率为63.04％.BRD4蛋白的表达与E-Cadherin和Vimentin蛋白表达呈正相关(r=0.591、0.981,P＜0.05).BRD4高表达组患者3年复发率(45.10％)明显低于低表达组患者(19.54％),差异有统计学意义(LogRank=3.011,P＜0.01).结论 BRD4蛋白参与了乳腺癌细胞上皮间充质转化,与乳腺癌患者术后复发密切相关.%Objective To investigate the effect of Bromodomain 4 (BRD4) protein on epithelial-mesenchymal transition of breast cancer cells and its relationship with prognosis after operation.Methods BRD4 knockdown cell lines (experimental group) and control group were established by BRD4 short hairpin RNA (shRNA) lentivirus and vector lentivirus in MCF-7 breast cancer cells,respectively.The expression levels of E-cadherin and Vimentin were analyzed by Western blotting and the invasive ability of cells in control group and observation group was analyzed by Transwell.The expression of BRD4,E-Cadherin and Vimentin in breast cancer tissues was analyzed by immunohistochemistry.The relationship between the expression of BRD4 and recurrence was analyzed.Results BRD4 knockdown cell lines were successfully established in this study.Western blotting analysis showed that the expression levels of E-Cadherin and Vimentin in the control group (0.57 ±0.12 and 0.64 ±0.18) were significantly higher than those in the observation group (0.26 ±0.09 and 0.31 ±0.08,t =3.990,P ＜0.01;t =4.109,P ＜0.01).The invasive ability of the control group (128.43 ± 15.32) was significantly higher than that in the experimental group (39.76 ± 9.12) (t =3.132,P ＜ 0.01).Among 138 patients,51 had high expression of BRD4 (36.96％),and 87 had low expression (63.04％).The expression of BRD4 protein was positively correlated with the expression of E-Cadherin and Vimentin (r=0.591 and 0.981 respectively,P＜0.05).The 3-year recurrence rate (45.10％) in the BRD4 overexpression group was significantly lower than that in the low expression group (19.54％) (LogRank =3.011,P ＜ 0.01).Conclusion BRD4 protein is involved in the epithelial-mesenchymal transition of breast cancer cells and is closely related to the recurrence of breast cancer after operation.