目的

应用短发夹RNA（short hairpin RNA，shRNA）抑制乳腺癌MDA-MB-231细胞胰岛素样生长因子1型受体（type Ⅰ insulin-like growth factor receptor，IGF-1R）的表达，探讨IGF-1R对乳腺癌体外增殖和迁移的作用。

方法

构建携带有绿色荧光蛋白报告基因的IGF-1R shRNA质粒载体，脂质体介导转染MDA-MB-231细胞，通过倒置荧光显微镜检测转染效率，CCK-8法检测细胞增殖能力，体外迁移实验检测细胞迁移能力。细胞增殖实验结果的组间比较采用重复测量方差分析和多元方差分析，RT-PCR定量结果和迁移实验结果的组间比较采用单因素方差分析。

结果

成功构建IGF-1R shRNA质粒载体，转染效率为55%～60%。IGF-1R shRNA转染MDA-MB-231细胞后，MDA-MB-231细胞IGF-1R mRNA与蛋白表达水平显著下降；细胞体外增殖和迁移能力受到显著抑制（P均＜0.05）。

结论

IGF-1R shRNA表达质粒可以有效抑制MDA-MB-231细胞IGF-1R的表达，显著抑制乳腺癌细胞的体外增殖和迁移能力。

Objective

To investigate the effect of short hairpin RNA（shRNA）-mediated inhibition of type I insulin-like growth factor receptor（IGF-1R）on breast cancer cell MDA-MB-231.

Methods

Breast cancer cell MDA-MB-231 was transfected with an IGF-1R shRNA plasmid vector labled with green fluorescent protein.The transfected cells were visualized by fluorescent microscope.The expression levels of IGF-1R mRNA and protein were detected respectively by RT-PCR and Western blot.The cell proliferation was evaluated by CCK-8 assay，and cell migration capacity was evaluated by transwell migration assay.Repeated measures ANOVA and multivariate analysis of variance were carried out for comparison of cell proliferation between groups，and analysis of variance was used for comparison of cell migration and the results by RT-PCR between groups.

Results

IGF-1R shRNA plasmid vector was successfully established.The transfection efficiency was 55%—60%.IGF-1R shRNA effectively down-regulated IGF-1R mRNA and protein expression.The proliferation and migration capacity of MDA-MB-231 cells were also effectively inhibited when compared to control shRNA（all P＜0.05）.

Conclusion

IGF-1R shRNA expression plasmid can effectively decrease IGF-1R gene expression，and inhibit the proliferation and migration capacity of MDA-MB-231 cell in vitro.