中文摘要：

目的：观察乳腺癌多药耐药细胞MCF-7／ADR中Twist表达及上皮-间质转化现象．探讨其与MCF-7／ADR侵袭转移能力增强的相关性。方法：分别以RT-PCR法、链霉亲和素-生物素酶复合物（Strept avidin biotin complex，SABC）免疫组织化学方法和Western blot法检测乳腺癌细胞系MCF-7及其多药耐药株MCF-7／ADR中介导EMT发生的转录因子Twist、上皮性标记基因E-钙粘素（E—cadherin）和间质性标记基因N-钙粘素（N—cadherin）表达的改变情况。结果：亲本细胞MCF-7中E—cadherin mRNA的表达和蛋白水平的表达均为阳性，Twist和N—cadherin表达阴性；多药耐药株MCF-7／ADR中E—cadherin mRNA和蛋白表达缺失，而在亲本细胞MCF-7中不表达的Twist和N—cadherin表达阳性。结论：在多药耐药乳腺癌细胞MCF-7／ADR中．其侵袭力增强可能与Twist介导的EMT发生有关。

英文摘要：

Objective： To study the epithelial to mesenchymal transition and expression level of Twist in MCF-7/ADR multidrug resistant breast cancer cells and to determine the relationship between multidrug resistance （MDR） and metastatic behavior. Methods： RT-PCR, immunohistochemical staining and western blotting were used to detect the changes in expression levels of the transcription factor Twist, E-cadherin and N-cadherin in the breast cancer cell line MCF-7 and its multidrug resistant variant MCF-7/ADR. Results： In MCF-7 cells, the expression of E-cadherin can be detected, but that of Twist and N-cadherin cannot be detected. The expression of E-cadherin in MCF-7/ADR cells was absent and the other two genes were significantly expressed. Conclusions： During the development of MDR, epithelial to mesenchymal transition induced by Twist may be related to the enhanced invasion and metastatic potential of multidrug resistant breast cancer cells MCF-7/ADR.