Gold nanoparticle cellular uptake, toxicity and radiosensitisation in hypoxic conditions.

Abstract Background and purpose Gold nanoparticles (GNPs) are novel agents that have been shown to cause radiosensitisation in vitro and in vivo . Tumour hypoxia is associated with radiation resistance and reduced survival in cancer patients. The interaction of GNPs with cells in hypoxia is explored. Materials and methods GNP uptake, localization, toxicity and radiosensitisation were assessed in vitro under oxic and hypoxic conditions. Results GNP cellular uptake was significantly lower under hypoxic than oxic conditions. A significant reduction in cell proliferation in hypoxic MDA-MB-231 breast cancer cells exposed to GNPs was observed. In these cells significant radiosensitisation occurred in normoxia and moderate hypoxia. However, in near anoxia no significant sensitisation occurred. Conclusions GNP uptake occurred in hypoxic conditions, causing radiosensitisation in moderate, but not extreme hypoxia in a breast cancer cell line. These findings may be important for the development of GNPs for cancer therapy.