CELL SITE SPECIFIC MICROBEAM IRRADIATION AND RESPONSE

描述(由申请者提供)：研究目标是 理解辐射诱发的识别和处理的基础 病变位于已知辐射击中和已知未击中的旁观者细胞中。核DNA 与细胞有明确关系的变化显著影响人类健康 死亡、突变和致癌变化。基本的范式是直接 细胞核受损是唯一已带来的重要辐射靶点 值得商榷。这一质疑引发了关于 低剂量人体辐射危害外推的依据 区域，以及对放射治疗中合适的靶区体积的影响。一个 对命中细胞比例在人群中的作用的理解 辐射响应中的亚细胞成分可以通过以下方式有效地获得 微束的使用。高LET带电粒子的定向光束可以引发 亚细胞微体积的损伤程度显著。单细胞 显微镜检查可将基因产物/S定位于亚细胞区域。 已知HIT和已知旁观者细胞的单细胞基因表达分析 对这一方法进行补充。在这份提案中，我们将使用最近建立的 用于细胞部位特定微束照射的协议 系统评价细胞间距离的作用，包括细胞 接触，在人类成纤维细胞和人类上皮细胞群体中， 单独的和混合的。假设细胞间的缝隙连接 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.