中文摘要：

在建立乳腺癌细胞MCF-7高转移倾向亚克隆LM-MCF-7细胞株的基础上，为阐明LM-MCF-7细胞具有更强增殖和迁移能力的分子机制，对其相关分子及其信号转导途径进行了探讨．免疫印迹结果显示，与MCF-7细胞相比，LM-MCF-7细胞中P-ERK1／2水平显著升高．流式细胞术和“伤口愈合”实验结果表明，ERK1／2的特异性抑制剂PD98059可明显抑制LM-MCF-7细胞的高增殖和高迁移能力．免疫印迹检测发现，与MCF-7细胞相比，LM-MCF-7细胞中与增殖和迁移相关的因子，如β-catenin、细胞周期蛋白D1、磷酸化肌球蛋白轻链（p-MLC）和肌球蛋白轻链激酶（MLCK）的水平呈明显增高，PD98059对这些因子水平的增高具有抑制作用．免疫荧光染色显示，LM-MCF-7细胞中β-catenin分布在细胞核中，应用PD98059处理后，β-catenin主要分布在胞浆中．上述研究结果表明，在LM-MCF-7细胞中活化的ERK1／2水平升高，是导致该细胞增殖和迁移能力增强的重要原因之一．与ERK1／2-MLCK-p-MLC和ERK1／2-β-catenin-细胞周期蛋白D1等信号转导途径有密切的关系．

英文摘要：

Based on the establishment of a high metastasis potential breast cancer cell line LM-MCF-7, derived from MCF-7 cell line, the related factors and their signal transduction pathways were investigated to demonstrate the molecular mechanism of enhanced proliferation and migration of LM-MCf-7 cells. Western blot analysis showed that p-ERK1/2 evidently increased in LM-MCf-7 cells by comparing with MCF-7 cells. Flow cytometry analysis and wound healing assay showed that the enhanced proliferation and migration of LM-MCF- 7 cells could be abolished by PD98059, a specific inhibitor of ERK1/2. The levels of the factors related to proliferation and migration, such as β-catenin, cyclinD1, p-MLC and myosin light chain kinasis （MLCK）, were higher in LM-MCF-7 cells than MCF-7 cells. However, the enhancement can be inhibited by PD98059. Immunofluorescence staining demonstrated that β-catenin mainly located in the nucleus of LM-MCF-7 cells. The β-catenin mainly showed in the cytoplasm after treatment with PD98059. The findings showed that high level of activated ERK1/2 was found in LM-MCF-7 cells, which was one of important reasons that proliferation and migration were enhanced in the cells. Furthermore, the signal transduction pathways, such as ERK1/2- MLCK-p-MLC and ERK1/2- β-catenin- cyclinD1, were involved in the evens.