The potential value of the neutral comet assay and γH2AX foci assay in assessing the radiosensitivity of carbon beam in human tumor cell lines

Authors

  • Jin Zhao Northwest University for Nationalities
  • Zhong Guo Northwest University for Nationalities
  • Hong Zhang Chinese Academy of Science
  • Zhen-Hua Wang Yantai University
  • Lei Song Northwest University for Nationalities
  • Jian-Xiu Ma
  • Shu-Yan Pei
  • Chen-Jing Wang

Abstract

Background. Carbon ions (12C6+) are high linear energy transfer (LET) radiation characterized by higher relative biological effectiveness than low LET radiation. The assessment of tumour radiosensitivity would be particularly useful in optimizing the radiation dose during radiotherapy. The aim of the current study was to evaluate the potential value of the neutral comet assay and γH2AX foci assay in assessing 12C6+ radiosensitivity of tumour cells.

Materials and methods. The doses of 12C6+ and X-rays used in the present study were 2 and 4 Gy. The survival fraction, DNA double-strand breaks (DSB) and repair kinetics of DSB were assayed with clonogenic survival, neutral comet assay and γH2AX foci assay in human cervical carcinoma HeLa cells, hepatoma HepG2 cells, and mucoepidermoid carcinoma MEC-1 cells at the time points of 0.5, 4, 16 and 24 h after 12C6+ and X-rays irradiation.

Results. The survival fraction for 12C6+ irradiation was much more inhibited than for X-rays (p < 0.05) in all three tumour cell lines tested. Substantial amounts of residual damage, assessed by the neutral comet assay, were present after irradiation (p < 0.05). The highest residual damage was observed at 0.5 or 4 h, both for 12C6+ and X-ray irradiation. However, the residual damage in HeLa and MEC-1 cells was higher for 12C6+ than X-rays (p < 0.05). The strongest induction of γH2AX foci was observed after 30 min, for all three tumour cell lines (p < 0.01). The franction of γH2AX foci persisted for at least 24 h after 12C6+ irradiation; in HeLa cells and MEC-1 was higher than after X-ray irradiation (p < 0.05). The correlation coefficients between the clonogenic survival, neutral comet assay and γH2AX foci assay were not statistically significant, except for some tumour cells at individual irradiation doses and types.

Conclusions. Our study demonstrated that the neutral comet assay and γ-H2AX foci assay could be used to assess the radiosensitivity of 12C6+ in human tumour cells.

Author Biographies

Jin Zhao, Northwest University for Nationalities

Medical College

Zhong Guo, Northwest University for Nationalities

Medical College

Hong Zhang, Chinese Academy of Science

Institution of Modern Physics

Zhen-Hua Wang, Yantai University

School of Life Sciences

Lei Song, Northwest University for Nationalities

Medical College

Jian-Xiu Ma

Shu-Yan Pei

Chen-Jing Wang

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Published

2013-08-27

How to Cite

Zhao, J., Guo, Z., Zhang, H., Wang, Z.-H., Song, L., Ma, J.-X., Pei, S.-Y., & Wang, C.-J. (2013). The potential value of the neutral comet assay and γH2AX foci assay in assessing the radiosensitivity of carbon beam in human tumor cell lines. Radiology and Oncology, 47(3). Retrieved from https://www.radioloncol.com/index.php/ro/article/view/1101

Issue

Section

Experimental oncology