Increased γ-H2AX by exposure to a 60-Hz magnetic fields combined with ionizing radiation, but not hydrogen peroxide, in non-tumorigenic human cell lines

Abstract

Purpose: Genotoxic effects have been considered the gold standard to determine if an environmental factor is a carcinogen, but the currently available data for extremely low frequency time-varying magnetic fields (ELF-MF) remain controversial. As an environmental stimulus, the effect of ELF-MF on cellular DNA may be subtle. Therefore, a more sensitive method and systematic research strategy are warranted to evaluate genotoxicity.

Materials and methods: We investigated the effect of ELF-MF in combination with ionizing radiation (IR) or H₂O₂ on the DNA damage response of expression of phosphorylated H2AX (γ-H2AX) and production of γ-H2AX foci in non-tumorigenic human cell systems consisting of human lung fibroblast WI-38 cells and human lung epithelial L132 cells.

Results: Exposure to a 60-Hz, 2 mT ELF-MF for 6 h produced increased γ-H2AX expression, as well as γ-H2AX foci production, a common DNA double-strand break (DSB) marker. However, exposure to a 1 mT ELF-MF did not have the same effect. Moreover, 2 mT ELF-MF exposure potentiated the expression of γ-H2AX and γ-H2AX foci production when combined with IR, but not when combined with H₂O₂.

Conclusions: ELF-MF could affect the DNA damage response and, in combination with different stimuli, provide different effects on γ-H2AX.

Keywords::

• Extremely low frequency
• combined treatment
• γ-H2AX
• ionizing radiation
• H₂O₂

Acknowledgements

This work was supported by a Power Generation & Electricity Delivery of the Korea Institute of Energy Technology, Evaluation, and Planning (KETEP) grant, funded by the Korean Ministry of Knowledge Economy, with additional support from the Ewha Global Top 5 Grant 2011 of Ewha Womans University.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.