Functionalized Selenium Nanosystem as Radiation Sensitizer of 125I Seeds for Precise Cancer Therapy

Although radiotherapy has been extensively applied in cancer treatment, external beam radiation therapy is still unable to avoid damage to adjacent normal tissues in the process of delivering a sufficient radiation dose to the tumor sites of patients. To overcome this limitation, chemoradiotherapy, as a combination of chemotherapy and radiotherapy of a radioactive seed, has been proposed to decrease the damage to tumor-surrounding tissues and enhance the radiosensitivity of solid tumors. In this study, we designed and synthesized folic acid-conjugated selenium nanoparticles (FA@SeNPs) as a cancer-targeting agent that could be synergistically enhanced by radioactive 125I seeds to realize anticancer efficacy and inhibited colony formation ability. Interestingly, when compared with X-ray irradiation, 125I seeds demonstrate a larger synergistic effect with the FA@SeNPs, drastically increasing reactive oxygen species overproduction to trigger apoptosis and influencing the cell cycle distribution in human breas...