Role of EGFR in DNA Repair and Radiation Response in Non Small Cell Lung Cancer

EGFR 在非小细胞肺癌 DNA 修复和放射反应中的作用

• 批准号: 8265309
• 负责人: Chaitanya Suresh Nirodi
• 金额: $ 6.04万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-07-01 至 2012-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8265309
• 关键词: Address; Binding; Cell Line; Cell Nucleus; DNA; DNA Damage; DNA Double Strand Break; DNA Repair; DNA Repair Pathway; DNA-PKcs; DNA-dependent protein kinase; Defect; Diagnosis; Dose; Double Strand Break Repair; Ectopic Expression; Employee Strikes; Enzymes; Epidermal Growth Factor Receptor; Erlotinib; Exhibits; Gefitinib; Genetic; Goals; Ionizing radiation; KRAS2 gene; Kinetics; Link; Malignant Epithelial Cell; Malignant neoplasm of lung; Mediating; Molecular; Mutate; Mutation; Neoplasms; Non-Small-Cell Lung Carcinoma; Nonhomologous DNA End Joining; Nuclear Import; Nuclear Localization Signal; Nuclear Translocation; Pathway interactions; Patients; Phenotype; Preparation; Protein Kinase Interaction; Radiation; Radiation Induced DNA Damage; Radiation Tolerance; Radiation therapy; Radioprotection; Reagent; Reporting; Resistance; Role; Simulate; Site; Survival Rate; Testing; Tyrosine Kinase Domain; Tyrosine Kinase Inhibitor; abstracting; chemotherapy; lung Carcinoma; mutant; nucleocytoplasmic transport; prevent; receptor; receptor binding; repaired; response; small molecule; tool; tumor

Abstract Radiotherapy, either alone, or in combination with chemotherapy, is frequently used in the treatment of patients with non-small cell lung carcinoma. However, tumor responses to ionizing radiation vary considerably and radiotherapy is not always effective in NSCLC patients. The epidermal growth factor receptor is an important determinant of radioresponse, whose elevated expression and activity frequently correlates with radioresistance in NSCLC tumors. We recently identified a subset of patient- derived NSCLC cell lines that exhibit marked sensitivity to radiation. A consistent feature among these NSCLCs is that they all harbor somatic, activating mutations in the tyrosine kinase domain (TKD) of the EGFR, that have also been linked to tumor sensitivity to small molecule tyrosine kinase inhibitors, gefitinib and erlotinib. We have assembled multiple lines of evidence that support a potential mechanism underlying mutant EGFR-associated radiosensitivity. The evidence reveals that, unlike the wild type EGFR, receptors with activating mutations in the TKD are not only defective in radiation- induced translocation to the nucleus but also fail to bind the catalytic and regulatory subunits of the DNA-dependent protein kinase (DNA-PK). Consequently, NSCLCs with TKD-mutated EGFR exhibit significant delays in the repair of DNA double strand break repair and poor clonogenic survival in response to radiation. A crucial finding is that ectopic expression of TKD-mutated forms of EGFR can radiosensitize different cell lines with diverse genetic backgrounds, including radioprotective mutations in KRAS and p53. Our study has identified a subset of naturally occurring EGFR mutations that abrogate a critical radioprotective function of EGFR. We will use these as tools to address three specific aims of our proposal: (1) To confirm that NSCLCs with mutations in the tyrosine kinase domain of EGFR are defective in repair of radiation-induced DNA damage (2) To test the hypothesis that mutations in the tyrosine kinase domain of EGFR block radiation-induced nuclear translocation of EGFR and compromise DSB repair and clonogenic survival (3) To test the hypothesis that mutations in the tyrosine kinase domain of EGFR prevent radiation-induced EGFR-DNA-PK interactions and compromise DSB repair and clonogenic survival. The long term goal is to develop a molecular rationale for a radiotherapeutic strategy in NSCLC patients that simulates the radiosensitizing effects of TKD- mutated EGFR. Relevance Statement Nearly 75% of all lung cancers manifest as non-small lung carcinoma. The median five-year survival rate for patients diagnosed with non-small lung cancer (NSCLC) is estimated at barely 14%. Radiotherapy is the first and sometimes only line of treatment for patients with NSCLCs. However, tumor resistance to ionizing radiation presents a major challenge to radiotherapeutic control of NSCLCs. Efficient DNA repair pathways in radioresistant tumors are frequently augmented by molecular determinants of radioresponse such as the epidermal growth factor receptor (EGFR). One of the critical radioprotective functions of EGFR involves radiation induced nuclear transport and interactions with key enzymes in DNA repair pathways. The immediate objective is to elucidate mechanisms underlying the radiosensitivity associated with a biologically distinct class of NSCLCs that harbor mutations in the tyrosine kinase domain (TKD) of EGFR. The long term goal is to develop a radiotherapeutic strategy that simulates the radiosensitizing effects of TKD-mutated EGFR in NSCLC patients.

抽象的 放射疗法，无论是单独使用，还是与化疗联合使用，通常用于治疗以下疾病： 非小细胞肺癌患者。然而，肿瘤对电离辐射的反应各不相同 且放疗对 NSCLC 患者并不总是有效。表皮生长因子 受体是放射反应的重要决定因素，其表达和活性升高 通常与 NSCLC 肿瘤的放射抗性相关。我们最近确定了一部分患者 衍生的 NSCLC 细胞系对辐射表现出明显的敏感性。其中有一个一致的特征 非小细胞肺癌 (NSCLC) 的一个特点是，它们都含有体细胞的酪氨酸激酶结构域 (TKD) 激活突变 EGFR，也与肿瘤对小分子酪氨酸激酶抑制剂的敏感性有关， 吉非替尼和厄洛替尼。我们收集了多条证据来支持潜在的 EGFR 突变相关放射敏感性的潜在机制。证据表明，与 野生型 EGFR、TKD 中具有激活突变的受体不仅在辐射方面存在缺陷， 诱导易位到细胞核，但也无法结合催化和调节亚基 DNA 依赖性蛋白激酶 (DNA-PK)。因此，具有 TKD 突变 EGFR 的 NSCLC 表现出 DNA双链断裂修复的修复显着延迟且克隆存活率低 对辐射的反应。一个重要的发现是 TKD 突变形式的 EGFR 异位表达可以 对具有不同遗传背景的不同细胞系进行放射增敏，包括放射防护突变 在 KRAS 和 p53 中。我们的研究已经确定了自然发生的 EGFR 突变的一个子集 废除 EGFR 的重要放射防护功能。我们将使用这些作为工具来解决三个问题 我们提案的具体目标：（1）确认酪氨酸激酶结构域发生突变的非小细胞肺癌（NSCLC） EGFR 在修复辐射引起的 DNA 损伤方面有缺陷 (2) 检验以下假设 EGFR 酪氨酸激酶结构域的突变可阻断辐射诱导的核易位 EGFR 并损害 DSB 修复和克隆生存 (3) 检验以下假设： EGFR 的酪氨酸激酶结构域可防止辐射诱导的 EGFR-DNA-PK 相互作用， 损害 DSB 修复和克隆存活。长期目标是开发分子原理 用于 NSCLC 患者的放射治疗策略，模拟 TKD 的放射增敏作用 EGFR 突变。相关性声明 近 75% 的肺癌表现为非小细胞肺癌。中位五年生存率 据估计，诊断为非小细胞肺癌 (NSCLC) 的患者比例仅为 14%。 放射治疗是非小细胞肺癌患者的首选治疗方法，有时也是唯一的治疗方法。然而， 肿瘤对电离辐射的抵抗力对放射治疗控制提出了重大挑战 非小细胞肺癌。放射抗性肿瘤中有效的 DNA 修复途径经常通过以下方法得到增强： 放射反应的分子决定因素，例如表皮生长因子受体（EGFR）。之一 EGFR 的关键辐射防护功能涉及辐射诱导的核转运和 与 DNA 修复途径中关键酶的相互作用。近期目标是阐明 与一类生物学上不同的 NSCLC 相关的放射敏感性的潜在机制 EGFR 酪氨酸激酶结构域 (TKD) 存在突变。长期目标是开发一个 模拟 TKD 突变 EGFR 在 NSCLC 中的放射增敏作用的放射治疗策略 患者。