Melissa Manser, Mohamad R. Abdul Sater, Christoph D. Schmid, Faiza Noreen, Manuel Murbach, Niels Kuster, David Schuermann, and Primo Schär, Scientific Reports 2017, Volume 7, Article number: 43345, online: 07 March 2017, DOI: 10.1038/srep43345.
Extremely-low-frequency magnetic fields (ELF-MF) have been classified as “possibly carcinogenic” to humans on the grounds of an epidemiological association of ELF-MF exposure with an increased risk of childhood leukemia. Yet, underlying mechanisms have remained obscure. Genome instability seems an unlikely reason, as the energy transmitted by ELF-MF is too low to damage DNA and induce cancer-promoting mutations. ELF-MF, however, may perturb the epigenetic code of genomes, which is well-known to be sensitive to environmental conditions and generally disrupted in cancers, including leukemia. We examined the potential of ELF-MF to influence key epigenetic modifications in leukemic Jurkat cells and in human CD34+ hematopoietic stem cells undergoing in vitro differentiation into the neutrophilic lineage. During granulopoiesis, sensitive genome-wide profiling of multiple replicate experiments did not reveal any statistically significant, ELF-MF-dependent alterations in the patterns of active (H3K4me2) and repressive (H3K27me3) histone markers or in DNA methylation. However, ELF-MF exposure showed consistent effects on the reproducibility of these histone and DNA modification profiles, which appear to be of a stochastic nature but show preferences for the genomic context. The data indicate that ELF-MF exposure stabilizes active chromatin, particularly during the transition from a repressive to an active state during cell differentiation.
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