Development of double strand RNA mPEI nanoparticles and application in treating invasive breast cancer.

Triple negative breast cancer (TNBC) has been characterized as a very heterogeneous subtype, and is more invasive and non-expressing of the genes for the estrogen receptor (ER), progesterone receptor (PR) and HER2/neu, with poor prognosis, and hence the efficacy of regular chemotherapy is very limited. Here, we report a kind of double strand RNA (dsRNA) mPEI nanoparticle for treatment of invasive TNBC. The studies were performed on TNBC cells and in TNBC cancer-bearing mice. The results showed that dsRNA mPEI nanoparticles were able to effectively transfect cells, and demonstrated a strong capability in knocking-down the Fra-1 gene and down-stream MMP-1 and MMP-9 genes in TNBC cells and TNBC cancer-bearing mice, thereby inhibiting the invasion and migration of cells. After intratumoral injection, dsRNA mPEI nanoparticles exhibited a robust anticancer efficacy in TNBC cancer-bearing mice, and the anticancer efficacy was superior to that of paclitaxel. In conclusion, dsRNA mPEI nanoparticles are able to effectively treat aggressive TNBC, and the mechanism studies reveal that they take effect by knocking-down Fra-1 relevant genes, hence interfering in transcription and translation of the genes, which are necessary for growth and metastasis of TNBC. Therefore, the present study offers a new and promising formulation and strategy for effective treatment of TNBC.