CaCO3/CaIP6 composite nanoparticles effectively deliver AKT1 small interfering RNA to inhibit human breast cancer growth

BACKGROUND Small interfering RNA (siRNA)-mediated gene therapy is a promising strategy to temporarily inhibit the expression of genes involved in development of breast cancer. The lack of a safe and efficient gene delivery system has become a major hurdle for siRNA-mediated gene therapy in breast cancer. Our previous studies have demonstrated that inorganic amorphous calcium carbonate (ACC) hybrid nanospheres functionalized with CaIP6 (ACC/CaIP6) nanoparticles are an efficient nucleic acid delivery tool. The present study aimed to evaluate the safety and efficiency of ACC/CaIP6 in delivering siRNA targeting AKT1 (siAKT1) for the treatment of breast cancer. METHODS The cytotoxicity of the ACC/CaIP6 nanoparticles was evaluated using a tetrazolium assay. The transfection efficiency and intracellular distribution of ACC/siAKT1 were analyzed by flow cytometry and confocal laser scanning microscopy, respectively. A series of in vitro and in vivo assays was performed to evaluate the effects of ACC/CaIP6/siAKT1 on growth of breast cancer cells. RESULTS ACC/CaIP6 nanoparticles effectively transfected cells with little or no toxicity. AKT1 knockdown by ACC/CaIP6/siAKT1 inhibited cell cycle progression and promoted apoptosis of MCF-7 cells. Intratumoral injection of ACC/CaIP6/siAKT1 significantly suppressed the growth of breast cancer in mice. CONCLUSION ACC/CaIP6 nanoparticles are a safe and efficient method of delivering siRNA for gene therapy in breast cancer.