期刊
ONCOGENE
卷 22, 期 36, 页码 5545-5553出版社
NATURE PUBLISHING GROUP
DOI: 10.1038/sj.onc.1206788
关键词
radiation; EGFRvIII; EGFR; MAP kinase; PI3 kinase; AKT
资金
- NCI NIH HHS [P01 CA72955, R01 CA65896] Funding Source: Medline
The constitutively active, truncated epidermal growth factor receptor EGFRvII lacks the ability of EGF binding due to a deletion of the NH2-terminal domain. EGFRvIII confers increased tumorigenicity, is coexpressed with EGFR wild type (wt) in human carcinoma and malignant glioma cells when grown as xenografts, but is not expressed in vitro. The effects of EGFRvIII expression on cellular radiation responses were studied in Chinese hamster ovary (CHO) cells transfected with plasmids expressing EGFRvIII (CHO.EGFRvIII) or EGFRwt (CHO.EGFRwt). CHO cells expressing similar levels of either receptor were employed to define their roles in response to EGF and ionizing radiation. EGF activated EGFRwt with no effect on EGFRvIII. In contrast, a single radiation exposure of 2 Gy resulted in a 2.8- and 4.3-fold increase in Tyr phosphorylation of EGFRwt and EGFRvIII, respectively. Downstream consequences of this radiation-induced activation were examined by inhibiting EGFRwt and EGFRvIII with AG1478 (kinase inhibitor). The radiation-induced 8.5-fold activation of the pro-proliferative mitogen-activated protein kinase and the 3.2-fold stimulation of the antiapoptotic AKT/phosphatidylinositol-3-kinase pathways by EGFRvII far exceeded that in CHO.EGFR wt cells. Thus, based on colony formation and apoptosis assays, EGFRvIII expression conferred a stronger cytoprotective response to radiation than EGFRwt, resulting in relative radioresistance. Therefore, disabling EGFRvIII in addition to EGFRwt needs to be considered in any therapeutic approach aimed at targeting EGFR for tumor cell radiosensitization.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据