Gold nanoparticles as a potent radiosensitizer in neutron therapy

// Eun Ho Kim 1 , Mi-Sook Kim 2 , Hyo Sook Song 3 , Seung Hoon Yoo 1 , Sei Sai 4 , Kwangzoo Chung 5 , Jiwon Sung 3 , Youn Kyoung Jeong 6 , YunHui Jo 3 and Myonggeun Yoon 3 1 Division of Heavy Ion Clinical Research, Korea Institute of Radiological and Medical Sciences, Seoul, Korea 2 Department of Radiation Oncology, Korea Institute of Radiological and Medical Sciences, Seoul, Korea 3 Department of Bio-convergence Engineering, Korea University, Seoul, Korea 4 Department of Basic Medical Sciences for Radiation Damages, National Institute of Radiological Sciences, Chiba, Japan 5 Department of Radiation Oncology, Samsung Medical Center, Seoul, Korea 6 Research Center for Radiotherapy, Korea Institute of Radiological and Medical Sciences, Seoul, Korea Correspondence to: Myonggeun Yoon, email: radioyoon@korea.ac.kr Mi-Sook Kim, email: mskim@kirams.re.kr Keywords: gold nanoparticles, neutron therapy, radiosensitizer, cancer, γ-ray Received: May 23, 2017      Accepted: July 25, 2017      Published: August 03, 2017 ABSTRACT The purpose of this study was to investigate the potential of gold nanoparticles as radiosensitizer for use in neutron therapy against hepatocellular carcinoma. The hepatocellular carcinoma cells lines Huh7 and HepG2 were irradiated with γ and neutron radiation in the presence or absence of gold nanoparticles. Effects were evaluated by transmission electron microscopy, cell survival, cell cycle, DNA damage, migration, and invasiveness. Gold nanoparticles significantly enhanced the radiosensitivity of Huh7 and HepG2 cells to γ-rays by 1.41- and 1.16-fold, respectively, and by 1.80- and 1.35-fold to neutron radiation, which has high linear energy transfer. Accordingly, exposure to neutron radiation in the presence of gold nanoparticles induced cell cycle arrest, DNA damage, and cell death to a significantly higher extent, and suppressed cell migration and invasiveness more robustly. These effects are presumably due to the ability of gold nanoparticles to amplify the effective dose from neutron radiation more efficiently. The data suggest that gold nanoparticles may be clinically useful in combination therapy against hepatocellular carcinoma by enhancing the toxicity of radiation with high linear energy transfer.