目的： 构建miRNA-126的重组真核表达载体，研究其对小鼠乳腺癌4T1细胞增殖和迁移的影响。 方法: 设计合成miRNA-126的正义和反义寡核苷酸，构建真核表达载体pcDNA6.2-miR-126，体外瞬时转染至4T1细胞，荧光显微镜下观测转染效率。Real-time PCR检测4T1细胞中miRNA-126的表达，MTT法和克隆形成实验检测4T1细胞的增殖和克隆形成能力，划痕法观察4T1细胞的体外迁移。 结果： 成功构建pcDNA6.2-miR-126真核表达载体，其可在4T1细胞中有效表达miR-126。与转染空质粒组（pcDNA6.2-Ctrl）相比，瞬时转染72 h后，pcDNA6.2-miR-126转染组4T1细胞的体外增殖能力受到明显抑制\[(030±0.03) vs (0.51±0.04)，P<0.05\]；瞬时转染48 h后，pcDNA6.2-miR-126组4T1细胞迁移能力也受到明显抑制\[(817±2.30) vs (28.33±2.16)个，P<0.05\]。 结论： miRNA-126过表达可抑制乳腺癌4T1细胞的增殖及迁移。

Objective:To construct a recombinant eukaryotic expression vector encoding miRNA-126 and to explore its effect on proliferation and migration of mouse breast cancer 4T1 cells. Methods: Sense and antisense oligonucleotides of miRNA-126 were designed and synthesized respectively. The eukaryotic expression vector pcDNA6.2-miR-126 was constructed and transiently transfected into 4T1 cells in vitro. The transfection efficiency was observed under a fluorescent microscope. The expression level of miRNA-126 in 4T1 cells was determined by real-time PCR. The proliferation and colony formation ability of 4T1 cells were detected by MTT assay and colony formation assay. The migration of 4T1 cells in vitro  was determined by scratch assay. Results: pcDNA62-miR-126 eukaryotic expression vector was successfully constructed and miRNA-126 was effectively expressed in 4T1 cells. Compared with that in empty plasmid transfected group (pcDNA6.2-Ctrl) , the proliferation capacity of 4T1 cells in vitro was obviously decreased in pcDNA6.2-miR-126 transfected group after transient transfection for 72 hours （\[0.30±0.03\] vs \[0.51±0.04\], P<0.05). The migration capacity of 4T1 cells in pcDNA6.2-miR-126 transfected group was also significantly inhibited after transfection for 48 hours (\[8.17±2.30\] vs \[28.33±2.16\], P<0.05). Conclusion:Overexpression of miRNA-126 may inhibit the proliferation and migration of breast cancer 4T1 cells.

国家自然科学基金资助项目（No. 81260398）；贵州省国际合作项目（No.10C315）；贵州省联合基金资助项目（No. 2011-51）