RADIATION SENSITIVITY OF QUIESCENT TUMOR CELLS

静止肿瘤细胞的辐射敏感性

• 批准号: 3187462
• 负责人: PETER C KENG
• 金额: $ 11.2万
• 依托单位: UNIVERSITY OF ROCHESTER
• 依托单位国家: 美国
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-08-05 至 1990-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3187462
• 关键词: DNA directed DNA polymerase; DNA repair; cell growth regulation; cellular oncology; chromosome disorders; clone cells; colony stimulating factor; flow cytometry; ionizing radiation; neoplasm /cancer chemotherapy; neoplasm /cancer radiation therapy; neoplastic cell; radiation genetics; radiation recovery; radiation sensitivity; radiobiology; radiotracer

The overall objective of this proposal is to investigate the basic cellular and molecular mechanisms of radiation responsiveness of quiescent cells. Quiescent cells exist in plateau phase monolayer cultures as well as multicellular spheroids and solid tumors and they have been implicated to be preferentially capable of repairing potentially lethal radiation damage (PLD). However, these cells have until recently been extremely difficult to identify and quantify, and the inherent radiation sensitivity of quiescent cells still remains unresolved especially for human tumor cells. Using the centrifugal elutriation and flow cytometry techniques recently developed in our laboratory to significantly enrich the quiescent cells, we propose to assess from plateau phase cultures and spheroids for: a) the radiation sensitivity of isolated quiescent tumor cells; b) radiation-induced alterations in the dynamics of recruitment from quiescent to proliferating compartments; c) the possible differential capacity of quiescent tumor cells for the repair of radiation-induced PLD; and d) the role of specific DNA- related ezymes (including one newly discovered enzyme) in the molecular mechanism(s) of repair. Relationships between cellular and molecular repair in quiescent cells will be studied by comparing the repair kinetics of DNA (strand breaks, DNA- protein crosslinks, DNA-DNA crosslinks) and chromosome damage to cell recovery at the same radiobiologically relevant doses. These studies will be performed with alkaline elution, DNA unwinding and premature chromosome condensation techniques. The results using these assays will be interrelated to determine which types of damage can be measured and related to radiation sensitivity of quiescent cells. Subsequent studies using inhibitors of DNA replication and repair will be performed on quiescent and proliferating cells and the effect of these inhibitors on the kinetics of the repair of radiation-induced PLD will be evaluated. Inhibitors are chosen to specifically inhibit DNA polymerases alpha, beta, delta I, delta II, topoisomerase I and II. A greater understanding of the mechanisms of quiescent cell radiation responsiveness, the kinetics of recruitment of quiescent to proliferating status, and the role of quiescent cells in the recovery of PLD, may provide basic information relevant to both radiation therapy and chemotherapy.

该提案的总体目标是调查基本 辐射反应的细胞和分子机制 静止细胞。 静止细胞存在于平台期单层中 培养物以及多细胞球体和实体瘤 他们被暗示优先有能力 修复潜在致命的辐射损伤（PLD）。 然而， 直到最近这些细胞还极其难以识别 并量化，以及静态的固有辐射敏感性 细胞的问题仍然悬而未决，特别是对于人类肿瘤细胞。 使用离心淘析和流式细胞术技术 我们实验室最近开发的产品显着丰富了 静止细胞，我们建议从平台期培养物进行评估 和球体：a) 孤立静态的辐射敏感性 肿瘤细胞； b) 辐射引起的动力学变化 从静止区室向增殖区室的募集； c) 的 静息肿瘤细胞可能具有不同的能力 辐射诱导PLD的修复； d) 特定 DNA 的作用- 相关酶（包括一种新发现的酶） 修复的分子机制。 细胞之间的关系 静止细胞中的分子修复将被研究 比较 DNA 的修复动力学（链断裂、DNA- 蛋白质交联、DNA-DNA 交联）和染色体损伤 在相同的放射生物学相关剂量下细胞恢复。 这些研究将通过碱性洗脱、DNA 解旋和过早染色体浓缩技术。 使用这些测定的结果将相互关联以确定 哪些类型的损伤可以测量并与辐射相关 静止细胞的敏感性。 使用抑制剂的后续研究 DNA复制和修复将在静态和 增殖细胞以及这些抑制剂对增殖细胞的影响 将评估辐射诱导 PLD 修复的动力学。 选择抑制剂来特异性抑制 DNA 聚合酶 α、β、δ I、δ II、拓扑异构酶 I 和 II。 一个更大的 了解静态细胞辐射的机制 反应性，招募静态的动力学 增殖状态以及静止细胞在增殖中的作用 PLD 的恢复，可以提供与两者相关的基本信息 放射治疗和化学治疗。