质粒介导靶向c-myc的siRNA对MCF-7乳腺癌细胞增殖的影响

目的观察靶向原癌基因c-myc的siRNA对MCF-7人乳腺癌细胞c-myc/c-Myc表达及细胞增殖的影响。方法以原癌基因c-myc mRNA 589-609位碱基为靶序列构建靶向c-myc的siRNA真核表达质粒p-Mat01-1及其错配质粒p-Mis09-1,空质粒pEGFP-C1为对照,用脂质体Lipo2000包裹转染MCF-7细胞。采用RT-PCR、Western blot检测c-myc mRNA及蛋白表达,MTT法检测MCF-7细胞增殖。结果与pEGFP-C1及p-Mis09-1比较,转染p-Mat01-1能够特异性抑制MCF-7细胞c-myc mRNA(24h:P<0.01)及蛋白(5d:P<0.01)表达,显著降低MCF-7细胞增殖能力(3d:P<0.05,5、7d:P<0.01)。结论采用siRNA表达质粒技术能够有效抑制MCF-7乳腺癌细胞c-myc/c-Myc表达,初步证实下调c-myc/c-Myc表达能够抑制MCF-7细胞增殖,为RNA干扰技术在乳腺癌生物治疗中的应用打下一定实验基础。

Inhibition of Proliferation in MCF-7 Breast Cancer Cells by Plasmid-based siRNA Targeting to Oncogene c-myc

Objective To investigate the effects of plasmid-based siRNA targeting to oncogene c-myc on c-myc/c-Myc expressions and cells proliferation in MCF-7 breast cancer cells. Methods siRNA eukaryotic expression plasmid p-Mat01-1 targeting to the sequence 589-609 of oncogene c-myc and its mismatch plasmid p-Mis09-1 were constructed, and transiently transfected MCF-7 cells using Lipo2000. Semi-quantitative RT-PCR and Western blot were used to analyze the expressions of c-myc/c-Myc in MCF-7 cells, and cells proliferation was detected by MTT assay. Results p-Mat01-1 inhibited the expressions of c-myc mRNA (24 h: P<0.01) and c-Myc protein (5 d: P<0.01) in MCF-7 cells as compared with pEGFP-C1 and p-Mis09-1 controls, and suppressed the proliferation of MCF-7 cells significantly (3 d: P<0.05, 5,7 d: P<0.01). Conclusion Plasmid-based siRNA targeting to oncogene c-myc could inhibit the expressions of c-myc/c-Myc in MCF-7 breast cancer cells efficiently, suggesting that the downregulation of c-myc/c-Myc could suppress the proliferation of MCF-7 cells in vitro.