Gold Nanoparticles Increase PLK1-Specific Small Interfering RNA Transfection and Induce Apoptosis of Drug Resistance Breast Cancer Cells

Drug resistance is a major barrier that limits the effectiveness of chemotherapies against breast cancer. Here, gold nanoparticles (GNPs) characterized by good dispersivity, high stability, low cytotoxicity, and simple synthesis were developed to deliver small interfering RNA (siRNA) against PLK1 (PLK1-siRNA) and overcome the drug resistance of breast cancer cells. Compared with the commonly used Lipofectamine 2000, GNPs showed higher PLK1-siRNA delivery efficiency and resulted in the remarkable gene silencing of PLK1 in drug resistance breast cancer cells MCF-7/MDR1 with low cytotoxicity in vitro. Moreover, delivery of PLK1-siRNA by GNPs could cause 14.23% apoptosis of MCF-7/MDR1 cells, which was apparently higher than 11.01% apoptosis conducted by Lipofectamine 2000. In addition, GNPs showed strong X-ray attenuation coefficient, indicating the potential theranostic application of this system. Therefore, this study disclosed an important step in the use of GNPs as transfection vector of siRNA that will be of great benefit to gene therapy against drug resistant cancer