FLASH-RT不会影响染色体转位和结结构,超出CONV-RT剂量率的影响
Paul G Barghouth1, Stavros Melemenidis1, Pierre Montay-Gruel2
1Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA 94305, USA.
概括
超高剂量速率放射治疗 (FLASH-RT) 与传统剂量速率放射治疗 (CONV-RT) 相比,没有减少染色体转位. 在FLASH-RT和CONV-RT之间,无论氧气水平如何,DNA双链断裂修复和转位形成是相似的.
科学领域:
- 辐射瘤学 辐射瘤学
- 分子生物学分子生物学
- 遗传学 遗传学 是一个
背景情况:
- 放射治疗 (RT) 使用高能辐射来杀死癌细胞.
- 研究超高剂量速率 (FLASH) 与常规剂量速率 (CONV) RT 对DNA损伤的影响至关重要.
- 产生和修复DNA双链断裂 (DSB) 是RT的关键结果.
研究的目的:
- 为了测试FLASH-RT产生的染色体转位比CONV-RT少的假设.
- 为了比较FLASH-RT和CONV-RT之间的DNA双链断裂修复和转位形成.
- 评估不同氧气压力对这些过程的影响.
主要方法:
- 在HEK293T细胞中利用FLASH验证的电子束和高通量全基因组转位序列 (HTGTS-JoinT-seq).
- 引入了Cas9"诱"DSB来测量诱近端修复和全基因组转移到"猎物"DSB.
- 照射细胞在CONV (0.08-0.13Gy/s) 和FLASH (1x10^2-5x10^6Gy/s) 剂量速率下在常态,物理和低氧条件下进行照射.
- 在293T和U87质母细胞瘤细胞中评估了克隆原性存活率和γH2AX点.
主要成果:
- 诺莫西克和物理氧辐射增加了转位和减少了诱近位修复,CONV-RT和FLASH-RT之间没有差异.
- 缺氧并没有增加染色体转位,而在缺氧下剂量调节速度也没有显示出转位水平或结节结构的显著差异.
- FLASH-RT与CONV-RT并没有改变γH2AX焦点数或293T克隆原性存活率.
结论:
- FLASH-RT产生了与CONV-RT无法区分的染色体转位和结结构.
- 氧张力不会改变FLASH-RT和CONV-RT之间的可比转位结果.
- 在不同条件下,FLASH-RT和CONV-RT之间的DNA损伤和修复概况是相似的.
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