分裂电离辐射后细胞再生长过程中的 DNA 甲基化变化。

DNA methylation changes in cells regrowing after fractioned ionizing radiation.

机构信息

Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center, Heidelberg, Germany.

出版信息

Radiother Oncol. 2011 Oct;101(1):116-21. doi: 10.1016/j.radonc.2011.05.048. Epub 2011 Jun 23.

DOI:10.1016/j.radonc.2011.05.048

PMID:21704414

Abstract

BACKGROUND AND PURPOSE

Repeated exposure to ionizing radiation (IR) can result in adaptive reactions. While DNA methylation changes in adaption to repeated stress exposure are established for a variety of drugs, their role in fractioned ionizing radiation is largely unknown.

MATERIAL AND METHODS

MCF7 breast cancer cells were treated 5 times a week with IR in fractions of 2 Gy, resulting in total doses of 10 and 20 Gy. Cells were harvested 48 and 72 h after the last irradiation, as well as after a recovery period of at least 14 d. To identify genes differentially methylated in irradiated versus non-irradiated cells, we used methyl-CpG immunoprecipitation (MCIp) followed by global methylation profiling on CpG island microarrays.

RESULTS

MCIp profiling revealed methylation changes in several CpG islands 48 h after FIR with 10 and 20 Gy. Cells receiving a total dose of 10 Gy started regrowing after 14 d and exhibited similar radioresistance as mock-treated cells. Differential methylation of the CpG units associated with FOXC1 (p<0.001) and TRAPPC9 (p<0.001) could be confirmed by time-of-flight mass spectrometry (Sequenom).

CONCLUSIONS

In summary, these data indicate that regrowth of MCF7 cells after 10 Gy FIR is associated with locus-specific alterations in DNA methylation.

摘要

背景与目的

反复暴露于电离辐射（IR）会导致适应性反应。虽然各种药物的应激暴露适应过程中的 DNA 甲基化变化已得到证实，但在分次电离辐射中其作用尚不清楚。

材料与方法

MCF7 乳腺癌细胞每周接受 5 次 IR 照射，每次 2 Gy，总剂量分别为 10 和 20 Gy。末次照射后 48 和 72 h 以及至少 14 d 的恢复期后收获细胞。为了鉴定在照射和非照射细胞中差异甲基化的基因，我们使用甲基化 CpG 免疫沉淀（MCIp），然后在 CpG 岛微阵列上进行全局甲基化谱分析。

结果

MCIp 谱分析显示，10 和 20 Gy FIR 后 48 h 时几个 CpG 岛的甲基化发生了变化。接受 10 Gy 总剂量的细胞在 14 d 后开始重新生长，并表现出与 mock 处理细胞相似的放射抗性。FOXC1（p<0.001）和 TRAPPC9（p<0.001）相关的 CpG 单位的差异甲基化可以通过飞行时间质谱（Sequenom）得到证实。