Enhancement of radiation effect and increase of apoptosis in lung cancer cells by thio-glucose-bound gold nanoparticles at megavoltage radiation energies

摘要

Gold nanoparticles (GNPs) (1-1,000 nm) modified by glucose have been considered to increase the toxicity of radiotherapy in human malignant cells. We report on the effect on lung-cancer cells, A549, of thio-glucose-bound gold nanoparticles (Glu-GNPs) with a size of 13 nm, combined with megavoltage (MV) X-ray. Viewed by transmission electron microscopy, Glu-GNPs were mainly distributed in the membrane-coated vesicles of A549 cells. The combination of Glu-GNPs with radiation resulted in a significant growth inhibition, compared with radiation alone (P < 0.05). Glu-GNPs enhanced radiation effect by increasing the ratio of A549 cells in the G2/M phase, and inducing more apoptosis. Furthermore, when combined with radiation, Glu-GNPs resulted in deregulation of Bcl-2 and upregulation of Bax and active caspase 3. Our results suggest that Glu-GNPs, as a new radiosensitizer, combined with radiation, can increase cytotoxicity on A549 cells not only by arresting the G2/M phase, but also by increasing apoptosis - probably via regulating the expression of Bcl-2 family of proteins and mitochondrial apoptotic pathway.