The effects of combined selenium nanoparticles and radiation therapy on breast cancer cells in vitro.

Radiosensitizers that increase cancer cell radio-sensitivity can enhance the effectiveness of irradiation and minimize collateral damage. Nanomaterial has been employed in conjunction with radiotherapy as radiosensitizers, due to its unique physicochemical properties. In this article, we evaluated selenium nanoparticles (Nano-Se) as a new radiosensitizer. Nano-Se was used in conjunction with irradiation on MCF-7 breast cancer cells, and efficacy and mechanisms of this combined treatment approach were evaluated. Nano-Se reinforced the toxic effects of irradiation, leading to a higher mortality rate than either treatment used alone, inducing cell cycle arrest at the G2/M phase and the activation of autophagy, and increasing both endogenous and irradiation-induced reactive oxygen species formation. These results suggest that Nano-Se can be used as an adjuvant drug to improve cancer cell sensitivity to the toxic effects of irradiation and thereby reduce damage to normal tissue nearby.