Silencing of the HER2eu Gene by siRNA Inhibits Proliferation and Induces Apoptosis in HER2eu-Overexpressing Breast Cancer Cells

摘要

In eukaryotes, double-stranded (ds) RNA induces sequence-specific inhibition of gene expression referred to as RNA interference (RNAi). We exploited RNAi to define the role of HER2eu in the neoplastic proliferation of human breast cancer cells. We transfected SK-BR-3, BT-474, MCF-7, and MDA-MB-468 breast cancer cells with short interfering RNA (siRNA) targeted against human HER2eu and analyzed the specific inhibition of HER2eu expression by Northern and Western blots. Transfection with HER2eu-specific siRNA resulted in a sequence-specific decrease in HER2eu mRNA and protein levels. Moreover, transfection with HER2eu siRNA caused cell cycle arrest at G0/G1 in the breast cancer cell lines SKBR-3 and BT-474, consistent with a powerful RNA silencing effect. siRNA treatment resulted in an antiproliferative and apoptotic response in cells overexpressing HER2eu, but had no influence in cells with almost no expression of HER2eu proteins like MDA-MB-468 cells. These data indicate that HER2eu function is essential for the proliferation of HER2eu-overexpressing breast cancer cells. Our observations suggest that siRNA targeted against human HER2eu may be valuable tools as antiproliferative agents that display activity against neoplastic cells at very low doses.