IN VIVO INDUCTION AND REPAIR OF GENOMIC INSTABILITY

基因组不稳定性的体内诱导和修复

• 批准号: 2683706
• 负责人: Antone L Brooks
• 金额: $ 13.34万
• 依托单位: WASHINGTON STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-09-30 至 2000-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2683706
• 关键词: DNA damage; DNA repair; X ray; animal genetic material tag; carcinogen testing; chromosome translocation; high energy particle; laboratory rat; micronucleus; mutagen testing; mutagens; radiation carcinogen; radiation carcinogenesis; radiation genetics; respiratory epithelium; respiratory neoplasm; tissue /cell culture

DESCRIPTION: (Applicant's Description) For genomic instability to be of importance in radiation biology, it has to be induced in vivo in epithelial cells that are at risk for radiation-induced cancer. Genomic instability could provide a great marker for cancer risk if cells with high radiation-induced cancer rates are also sensitive to the induction of genomic instability. This application will use an in vivo/in vitro approach to determine the relationship between cancer risk and genomic instability and will help understand the role of cytogenetic damage as a potential mechanisms for induction and repair of genomic instability. This application will address three hypotheses: (1) Genomic instability is related to the amount or type of initial chromosome damage. (2) Genomic instability can be induced in vivo in respiratory epithelial cells and is directly related to cell sensitivity for the induction of cancer. (3) Lesions which are responsible for genomic instability are lost as a function of time after the radiation exposure. Wistar rats will be exposed to graded doses of both low LET X-rays and HZE particles (10000 MeV/Amu). The high energy iron particles are similar to those encountered in space flight and will be generated by the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory. Cells from regions of the respiratory tract that are known to be sensitive to the induction of cancer from high LET particles, deep lung epithelial cells; areas where no radiation-induced cancers have been observed, tracheal epithelial cells; and cells known to show genomic instability, bone marrow, will be isolated and evaluated for genomic instability using cytogenetic end-points. The frequency of micronuclei provides an indicator of the relative biological effect (RBE) for initial cytogenetic damage as a function of radiation type. The induction of chromatid type aberrations after several cell generations in tissue culture will be evaluated as an indicator of radiation-induced genomic instability. In cell types and populations that show genomic instability, the relationship between stable chromosome aberrations and the induction of genomic instability will be evaluated using fluorescence in situ hybridization techniques (FISH). The repair of the lesions responsible for the induction of genomic instability will be evaluated by serial sacrifice of animals exposed to both high and low LET radiation and the culture of the cells over extended periods of time. This protocol will address the stated hypotheses and provide radiobiological understanding of the relationships that exist between cell types, clastogenic change, genomic instability, and cancer risk from exposure in vivo to low doses of HZE particles.

描述：（申请人的描述） 为了使基因组不稳定在辐射生物学中很重要，它必须 在有风险的上皮细胞中诱导 辐射诱导的癌症。 基因组不稳定性可以提供一个很好的标记 如果癌症诱发的癌症发生率高也是癌症风险 对诱导基因组不稳定性敏感。 此应用程序将 使用体内/体外方法来确定 癌症风险和基因组不稳定，将有助于了解 细胞遗传学损害作为诱导和修复的潜在机制 基因组不稳定性。 该应用程序将解决三个假设：（1） 基因组不稳定性与初始染色体的数量或类型有关 损害。 （2）可以在呼吸道体内诱导基因组不稳定性 上皮细胞，与细胞灵敏度直接相关 癌症的诱导。 （3）负责基因组的病变 辐射暴露后的时间的函数丢失了不稳定。 Wistar大鼠将暴露于低亮X射线和HZE的分级剂量 颗粒（10000 MEV/AMU）。 高能铁颗粒与 那些在太空飞行中遇到的人，将由交替产生 布鲁克黑文国家实验室的梯度同步器（AGS）。 来自 呼吸道区域已知对 从高分颗粒，深肺上皮细胞中诱导癌症； 未观察到没有辐射引起的癌症的区域，气管 上皮细胞；和已知显示基因组不稳定性的细胞，骨髓， 将使用细胞遗传学分离并评估基因组不稳定性 终点。 微核的频率提供了指标 初始细胞遗传学损伤的相对生物学作用（RBE）作为一个 辐射类型的功能。 染色单体类型的诱导 在组织培养的几代细胞后期将被评估为 辐射诱导的基因组不稳定性的指标。 在细胞类型中 显示基因组不稳定性的种群，稳定之间的关系 染色体畸变和基因组不稳定性的诱导将是 使用荧光原位杂交技术（FISH）评估。 这 修复负责诱导基因组不稳定性的病变 将通过对暴露于高高和高的动物的连续牺牲来评估 低点放射线和细胞的培养 时间。 该协议将解决陈述的假设，并提供 对细胞之间存在的关系的放射生物学理解 类型，那种层变化，基因组不稳定性和癌症风险 体内暴露于低剂量的HZE颗粒。