Killing Action of Cuprous Oxide Nanoparticles on Breast Cancer Cells

Breast cancer (BC), a common malignancy, is intractable at present. Cuprous oxide nanoparticles (Conps) are new nanoparticles crucial in inhibiting tumor progression according to early studies, but their role in BC remains unclear. Field emission-scanning electron microscopy (FESEM) and field emission–transmission electron microscopy (FETEM) were used for the morphological observation of Conps, and energy-dispersive X-ray spectroscopy was used for their elemental composition analysis. Multipoint nitrogen adsorption was used to determine the Brunauer–Emmet–Teller of Conps, and their mean hydrodynamic size and zeta potential in water and intact cell medium were determined by dynamic light scattering (DLS). 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, Cell Counting Kit-8, Transwell assay, and flow cytometry were used to determine the effects of Conps on the biological function of BC cells. Western blotting was used to determine the changes in apoptosis-related proteins. Using FESEM and FETEM based on DLS and zeta potential determination, Conps was successfully constructed. Conps significantly lowered the viability of BC cells in a dose-dependent manner, significantly inhibited cell proliferation, invasion, and migration activities, and induced cell apoptosis. Western blotting demonstrated that Conps up-regulated Bax and caspase-3 proteins and down-regulated Bcl-2 protein. The results suggest that Conps can suppress the proliferation, invasion, and migration of BC cells and accelerate their apoptosis. This is a new potential strategy for the clinical treatment of BC.