Nuclear epidermal growth factor receptor modulates cellular radio-sensitivity by regulation of chromatin access
Nuclear epidermal growth factor receptor modulates cellular radio-sensitivity by regulation of chromatin access
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DOI：
10.1016/j.radonc.2011.06.001
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发表时间：
2011-06-01
影响因子：
5.7
通讯作者：
Rodemann, H. Peter
中科院分区：
文献类型：
--
作者：
Dittmann, Klaus;Mayer, Claus;Rodemann, H. Peter
目的：核EGFR参与细胞应激管理和细胞放射敏感性调节。本研究的目的是阐明细胞核EGFR作用的分子模式。方法：用免疫组织化学和共聚焦显微镜分析辐射诱导的细胞核EGFR穿梭和EGFR灶形成。免疫沉淀后，通过蛋白质印迹法分析γ H（2）AX-蛋白质复合物的组成。在siRNA介导的EGFR耗竭后，分析了与ATM活化、组蛋白H3乙酰化、残留DNA损伤和照射后细胞存活有关的核EGFR功能相关性。EGFR共定位于γ H（2）AX病灶的亚部分。γ-H（2）AX复合物的组成分析表明，辐射反应中存在埃格、ATM、早幼粒细胞白血病蛋白（PML）、组蛋白H3和异染色质结合蛋白（HP 1）。EGFR蛋白的耗尽抑制ATM活化，由于抑制乙酰化酶TIP 60活性照射后。因此，组蛋白H3乙酰化和磷酸化被阻断，染色质不能打开进行修复。因此，照射后24小时，残留的DNA损伤增加，细胞被放射增敏。当细胞用EGFR-NLS-肽，阻断EGFR核shuttling specific.Conclusions：细胞核EGFR是DNA损伤修复复合物的一部分，并参与调节TIP 60-乙酰化酶的活性。TIP 60是ATM激活和染色质松弛所必需的，这是异染色质DNA中DNA修复的先决条件。因此，肿瘤治疗期间的干预性EGFR策略也可能通过阻断受损DNA的通路与DNA修复相互作用。(C)2011爱思唯尔爱尔兰有限公司保留所有权利。放射治疗和肿瘤学99（2011）317-322
Purpose: Nuclear EGFR is involved in cellular stress management and regulation of cellular radiosensitivity. The aim cif this study was to elucidate the molecular mode of nuclear EGFR action.Methods: Radiation induced nuclear EGFR-shuttling and EGFR-foci formation was analyzed with immunohistochemistry and confocal microscopy. Composition of gamma H(2)AX-protein complexes was analyzed by western-blotting after immuno-precipitation. Functional relevance of nuclear EGFR was analyzed after siRNA mediated depletion of EGFR with respect to activation of ATM, histone H3 acetylation, residual DNA-damage and cell survival after irradiation.Results: Following radiation nuclear EGFR was localized in foci similar to gamma H(2)AX. EGFR co-localized in a sub-fraction of gamma H(2)AX-foci. Analysis of composition of gamma H(2)AX-complexes revealed presence of EGER, ATM, promyelocytic leukemia protein (PML), histone H3 and hetero-chromatin binding protein (HP1) in response to radiation. Depletion of EGFR protein inhibited ATM activation due to inhibition of acetylase TIP60 activity following irradiation. Consequently, histone H3 acetylation and phosphorylation was blocked and chromatin could not be opened for repair. Thus, residual DNA-damage was increased 24 h after irradiation and cells were radio-sensitized. Comparable results were obtained when cells were treated with EGFR-NLS-peptide, which blocks EGFR nuclear shuttling specifically.Conclusions: Nuclear EGFR is part of DNA-damage repair complex and is involved in regulation of TIP60-acetylase activity. TIP60 is essential for ATM activation and chromatin relaxation which is a prerequisite for DNA-repair in heterochromatic DNA. Thus interventional EGFR strategies during tumor treatment may also interact with DNA-repair by blocking access to damaged DNA. (C) 2011 Elsevier Ireland Ltd. All rights reserved. Radiotherapy and Oncology 99 (2011) 317-322