Silencing of HER2 Receptor and Growth Inhibition of SKBR3 Breast Cancer Cells by Lentiviral-mediated RNAi

HER2, a member of epidermal growth factor receptor family proteins, is overexpressed in about 30% of human breast cancer. Increased levels of HER2 are associated with poor patient prognosis and enhanced metastasis. RNA interference (RNAi) is developed recently as a new technique which can inhibit gene expression specifically in mammalian cells. On the basis of previous study,in which two target sequences with favorable RNAi effect on HER2 were identified, a series of dual promoter siRNA-expressing vectors containing two opposing U6 and H1 promoters were constructed. After transfection of HER2-overexpressing SKBR3 breast cancer cells with the siRNA-expressing vectors, downregulation of HER2 was identified quantitatively. Subsequently, the siRNA-expressing cassettes were subcloned into lentiviral vectors by LR recombination reaction and lentivirus was prepared successfully. The results from infection of SKBR3 cells with siRNA-expressing lentivirus demonstrated that lentiviral-mediated RNAi could downregulate HER2 expression efficiently through fluorescent quantitative PCR (FQ-PCR), western blot, and FACS analysis. Furthermore, cell growth was inhibited in cell proliferation assay after treatment with siRNA lentivirus.A new tool for clarifying the function of HER2 in cancer metastasis and developing the gene therapy drug was offered.