大多数DNA修复缺陷不会改变CRISPR编辑细胞中相对生物有效性和线性能量转移之间的关系
Francisco D C Guerra Liberal1, Jason L Parsons2, Stephen J McMahon1
1The Patrick G Johnston Centre for Cancer Research, Queen's University Belfast, Belfast, UK.
Medical physics
|September 27, 2023
概括
DNA双链断裂 (DSB) 修复缺陷,特别是在非同源端结合 (NHEJ) 中,无论辐射类型如何,都显著增加了癌细胞的放射敏感性. 这凸显了DNA修复途径在确定辐射反应中的重要性.
科学领域:
- 辐射瘤学 辐射瘤学
- 分子生物学分子生物学
- 癌症遗传学 癌症遗传学
背景情况:
- 癌症辐射敏感性受到遗传变化的影响,但标准放射治疗剂量无法解释个体患者的变化.
- 质子和碳离子疗法由于较高的相对生物有效性 (RBE) 和线性能量转移 (LET) 提供了优势,但RBE的遗传依赖性尚未完全理解.
研究的目的:
- 通过研究具有特定DNA双链断裂 (DSB) 修复通路缺陷的细胞系来澄清RBE-LET关系.
- 孤立DSB修复通路对放射敏感性的影响,独立于其他遗传因素.
主要方法:
- 使用了基因改造的人类RPE1细胞,其ATM,BRCA1,DCLRE1C,LIG4,PRKDC和TP53有缺陷.
- 在暴露于光子,质子 (LET 1 和 12 keV/μm) 和α粒子 (129 keV/μm) 后,细胞存活率使用克隆基因分析进行评估.
- 计算了相对生物有效性 (RBE) 和敏感剂增强比率 (SER),并使用53BP1焦点量化了DNA双链断裂 (DSB) 修复.
主要成果:
- 非同源端结合 (NHEJ) 基因缺陷对光子产生了最高的敏感性 (SER 1.8-2.0),而同源重组 (HR) 基因缺陷的影响较小 (BRCA1-/- SER 1.2).
- 野生型细胞的RBE分别为1.1,1.3和5.0的低LET质子,高LET质子和α粒子.
- 在所有LET中,NHEJ缺陷细胞过敏,减少高LET的影响;HR缺陷细胞独立于LET表现出中度敏感性. 具有NHEJ缺陷的细胞表现出最小的DSB修复,特别是在高LET暴露后.
结论:
- 在DSB修复路径,特别是NHEJ中的缺陷,无论辐射线性能量转移 (LET) 是否,都会产生显著的辐射敏感性.
- 不同的DNA修复途径对细胞存活的贡献似乎独立于辐射质量 (LET).
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