Radiotherapy is one of the most widely used treatments for therapy of malignant tumors, but resistance to radiation of hypoxic cells in tumor tissues is still a serious concern. Previous studies have demonstrated that silver nanoparticles (AgNPs) enhance the radiosensitivity of human glioma cells in vitro, but the effect of AgNPs on hypoxic glioma cells has not been investigated in detail. The main purpose of this study is to evaluate the radiosensitizing efficacy of AgNPs on hypoxic glioma cells. The half maximal inhibitory concentration (IC50) values of AgNPs for the hypoxic U251 cells and C6 cells were 30.32 μg/mL and 27.53 μg/mL, respectively. The sensitization enhancement ratio (SER) demonstrated that AgNPs exhibit higher capacity in radiosensitization in hypoxic cells (U251: 1.78; C6: 1.84) than that in normoxic cells (U251: 1.34; C6: 1.45). The underlying mechanism of AgNPs’ radiosensitization in hypoxic cells is through the promotion of apoptosis and enhanced destructive autophagy. There is evidence of crosstalk between apoptosis and autophagy in AgNPs-radiosensitized hypoxic cells where inhibition of autophagy results in decreased apoptosis. These findings suggest that AgNPs can be used as a highly effective nano-radiosensitizer for the treatment of hypoxic glioma.

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.

Radiotherapy is one of the main strategies for cancer treatment but has significant challenges, such as cancer cell resistance and radiation damage to normal tissue. Radiosensitizers that selectively increase the susceptibility of cancer cells to radiation can enhance the effectiveness of radiotherapy. We report here the development of a novel radiosensitizer consisting of monodispersed ceria nanoparticles (CNPs) covered with the anticancer drug neogambogic acid (NGA-CNPs). These were used in conjunction with radiation in MCF-7 breast cancer cells, and the efficacy and mechanisms of action of this combined treatment approach were evaluated. NGA-CNPs potentiated the toxic effects of radiation, leading to a higher rate of cell death than either treatment used alone and inducing the activation of autophagy and cell cycle arrest at the G2/M phase, while pretreatment with NGA or CNPs did not improve the rate of radiation-induced cancer cells death. However, NGA-CNPs decreased both endogenous and radiation-induced reactive oxygen species formation, unlike other nanomaterials. These results suggest that the adjunctive use of NGA-CNPs can increase the effectiveness of radiotherapy in breast cancer treatment by lowering the radiation doses required to kill cancer cells and thereby minimizing collateral damage to healthy adjacent tissue.

Radiotherapy is one of the main therapeutic methods for cancers, but radiation resistance of cancer cells still remains a serious concern. Searching for radiosensitizers to overcome such resistance is therefore urgently required. The goal of this study is to evaluate and compare the radiosensitizing efficacy of Fe₃O₄-OA, Ag and Fe₃O₄@Ag nanoparticles on U251 cells. The results show that Fe₃O₄@Ag nanoparticles have the highest ability of radiosensitization among the three nanoparticles. The underlying mechanism of Fe₃O₄@Ag nanoparticles' radiosensitivity enhancement is through decrease of the cytoprotective autophagy at the early stage, and increase of the calcium-dependent apoptosis at the later stage. These findings suggest the potential application of Fe₃O₄@Ag nanoparticles as a highly effective nano-radiosensitizer for the treatment of glioblastoma cells.

Even though serum iron is a commonly used parameter in iron metabolism, it has not yet been applied for biological dosimetry purpose. A new biological dosimeter based on serum iron has been developed in this work. Serum iron levels in mice subjected to gamma rays from a 60Co source were detected with the use of ferrous. The doses are from 0.2–7 Gy with a dose rate of 0.2 Gy/min. The results demonstrate that serum iron level increases with increasing dose. The detection limit based on serum iron has a lower limit of dose detection of about 0.5 Gy and the maximal increase of serum iron observed is maintained 4 h after γ irradiation. Therefore the best suggested time for blood collection is within 4 h after γ irradiation. Two dose-response relationships were observed with both according to degrees of the increase of serum iron levels and different intervals after γ irradiation. The first is a linear relationship of y = 0.98x + 6.76 (r = 0.98) obtained 10 min after γ irradiation; the second is the linear quad...