CELL SITE SPECIFIC MICROBEAM IRRADIATION AND RESPONSE

描述（由申请人提供）：研究目标是针对 了解识别和处理辐射引起的 已知辐射击中和已知非击中旁观者细胞中的损伤。核DNA 变化显著影响人类健康，与细胞 死亡、突变和致癌变化。基本的范式是， 受损的细胞核是唯一重要的辐射目标 质疑这一问题引起了关于 低剂量辐射对人体照射危害的外推依据 区域，并且还影响放射治疗中的适当靶体积。一个 理解群体中命中细胞的分数的作用， 辐射响应中的亚细胞成分可以通过以下方式有效地获得： 使用MicroBeam。高LET带电粒子的定向束可以引发 在亚细胞微体积中的显著损伤水平。单细胞 显微镜检查可以将基因产物定位于亚细胞区域。 已知命中细胞和已知旁观者细胞的单细胞基因表达分析 补充这一做法。在本提案中，我们将使用最近建立的 细胞位点特异性微束照射的方案， 系统评价细胞间距离的作用，包括细胞 接触，在人成纤维细胞和人上皮细胞群体中， 单独和混合。据推测，细胞间隙连接 沟通是旁观者效应的一个次要组成部分。

DESCRIPTION (PROVIDED BY APPLICANT):Research objectives are directed toward understanding the basis for the recognition and processing of radiation induced lesions in known radiation hit and known non-hit bystander cells. Nuclear DNA changes significantly impact human health with clear relationships to cell death, mutation and oncogenic change. The basic paradigm that the directly damaged cell nucleus is the only important radiation target has been brought into question. This questioning arouses significant uncertainties about the basis for extrapolation of hazard to human radiation exposure in the low dose region, and also impacts on appropriate target volume in radiation therapy. An understanding of the role of the fraction of hit cells in a population and of sub-cellular components in radiation responses can efficiently be obtained by use of a microbeam. A directed beam of high LET charged particles can initiate significant levels of damage in sub-cellular micro-volumes. Single cell microscopic examination can localize gene product/s to sub-cellular regions. Single cell gene expression analyses of known hit and known bystander cells complement this approach. In this proposal we will use recently established protocols for cell site specific microbeam irradiation to undertake a systematic evaluation of the role of intercellular distance, including cell contact, in both human fibroblast and human epithelial cell populations, individually and mixed. It is hypothesized that gap junction intercellular communication is a minor component of the bystander effect.