The effect of gold nanoparticles on dose enhancement factor of human intestinal colon cancer HT-29 cells

Introduction: Radiation therapy is an important procedure for treatment of more than half of tumors. One way to increase the efficiency of radiation therapy is application of radiosensitizer at the site of tumor. gold nanoparticles (GNPs) have several characteristics that make them attractive for using with radiation therapy including small size (1–100 nm), biocompatibility, preferentially passive accumulation in tumor and the feasibility to surface modification to actively target cancerous cells. The aim of this paper was investigating the radiosensitizing effect of GNPs in human intestinal colon cancer HT-29 cells as a less radiosensitive tumor cell. Materials and Methods: Radiosensitizing effects of GNPs were comparatively evaluated in vitro for intestinal colon cancer (HT-29) cell line by colony formation assay at 6 MV photon energy. Cells were treated with only ionizing irradiation (IR) as control group or combination of GNPs and ionizing irradiation (GNPs+IR). GNPs had average size of 15 nm and were used at concentration of 0.1 mM. Results: The survival curve was obtained using MATLAB software and dose enhancement factor (DEF) was calculated by dividing of LD50 (50% lethal dose) of IR group with combination treatment group (GNPs+IR). GNPs could enhance treatment response by factor of 1.47(DEF=1.47). Conclusion: Our results showed that GNPs can sensitize HT-29 tumor cells and thus can be used to enhance the radiation therapy efficiency.