Radiation-induced alterations of histone post-translational modification levels in lymphoblastoid cell lines

Abstract

BackgroundRadiation-induced alterations in posttranslational histone modifications (PTMs) may affect the cellular response to radiation damage in the DNA. If not reverted appropriately, altered PTM patterns may cause long-term alterations in gene expression regulation and thus lead to cancer. It is therefore important to characterize radiation-induced alterations in PTM patterns and the factors affecting them.MethodsA lymphoblastoid cell line established from a normal donor was used to screen for alterations in methylation levels at H3K4, H3K9, H3K27, and H4K20, as well as acetylation at H3K9, H3K56, H4K5, and H4K16, by quantitative Western Blot analysis at 15 min, 1 h and 24 h after irradiation with 2 Gy and 10 Gy. The variability of alterations in acetylation marks was in addition investigated in a panel of lymphoblastoid cell lines with differing radiosensitivity established from lung cancer patients.ResultsThe screening procedure demonstrated consistent hypomethylation at H3K4me3 and hypoacetylation at all acetylation marks tested. In the panel of lymphoblastoid cell lines, however, a high degree of inter-individual variability became apparent. Radiosensitive cell lines showed more pronounced and longer lasting H4K16 hypoacetylation than radioresistant lines, which correlates with higher levels of residual γ-H2AX foci after 24 h.ConclusionSo far, the factors affecting extent and duration of radiation-induced histone alterations are poorly defined. The present work hints at a high degree of inter-individual variability and a potential correlation of DNA damage repair capacity and alterations in PTM levels.

Metabolomic Analysis of Mice Exposed to Gamma Radiation Reveals a Systemic Understanding of Total-Body Exposure

“…Concentrations of deoxyinosine and cytosine were evidence of DNA and RNA damage that occurred at the tissue level (26). Exposure to gamma radiation induces changes in histone post-translational (27, 28) modifications including γ-H2AX formation (27) and O -GlcNAc modification (28) that in turn affect DNA damage response and genome stability. Radiation exposure is known to affect all critical purine, pyrimidine, bile acid biosynthesis, glutathione metabolic pathways, and elevated UDP-GlcNAc (substrate for O -GlcNAc transferases) could be a sign of nutrient sensor for radiation injury to the ileum and leads to gastrointestinal syndrome (25).…”

Histone modifications predispose genome regions to breakage and translocation

“…In addition, increased γ-H2AX foci formation occurs at a defined region of transcribed genes relative to a gene-poor region after irradiation (Falk et al 2008). Changes in histone modifications may also affect the progression of the DNA damage response (DDR) by interfering with the restoration of baseline chromatin structure after repair (Ayrapetov et al 2014;Burgess et al 2014;Khurana et al 2014), since, in ASH2L-expressing cells, recondensation at the site of DNA damage as well as upstream DDR signaling is dampened (Burgess et al 2014), and γ-H2AX foci formation after irradiation is associated with loss of H3K4me3 (Seiler et al 2011;Lafon-Hughes et al 2013;Maroschik et al 2014). These observations suggest that H3K4 hypermethylation may impair DDR progression by counteracting condensation and signaling required for efficient DDR, thus resulting in persistent DSBs and enhancing the likelihood of formation of translocations.…”

The inter-individual variability outperforms the intra-individual variability of differentially expressed proteins prior and post irradiation in lymphoblastoid cell lines

“…GM03189 is commercially available (Coriell Institute, NJ, USA) and represents a radiosensitive LCL of an AT-patient. The LCLs 4060-200 (radio-sensitive) and 20037-200 (normal) are EBV immortalized B-lymphocytes from patients of the nationwide, multicentre LUCY-study (www.helmholtz-muenchen/epi/) and their individual radiation response was characterized (Guertler et al, 2009;Maroschik et al, 2014). All cell lines were grown at 37 C in a humified atmosphere of 5% CO 2 .…”

“…The other two cell lines derived from lung cancer patients of the LUCY study (Rosenberger et al, 2011). The LCL 4060-200 shows a radio-sensitive phenotype, whereas the second LUCY-cell line 20037-200 reacts normal or radioresistant in contrast to the other cell lines in the different endpoints that were tested (Guertler et al, 2009;Maroschik et al, 2014).…”