Identification of ATIC as a Novel Target for Chemoradiosensitization.
Identification of ATIC as a Novel Target for Chemoradiosensitization.
复制标题
DOI：
10.1016/j.ijrobp.2017.08.033
复制
发表时间：
2018-01-01
期刊：
影响因子：
--
通讯作者：
Concannon P
中科院分区：
文献类型：
--
作者：
Liu X;Paila UD;Teraoka SN;Wright JA;Huang X;Quinlan AR;Gatti RA;Concannon P
在一名接受辐射敏感性测试的受试者中，发现了编码 5-氨基咪唑-4-甲酰胺核糖核苷酸甲酰基转移酶/IMP 环水解酶 (ATIC) 的基因突变，ATIC 是一种双功能酶，催化嘌呤从头生物合成途径的最后两个步骤。进行功能研究以确定 ATIC 抑制是否具有放射增敏作用，如果是，则阐明该作用的机制并确定 ATIC 的小分子抑制剂是否可以充当有效的放射增敏剂。 siRNA 敲低和小分子抑制剂均用于灭活细胞培养物中的 ATIC。使用克隆形成存活测定、中性彗星测定和γH2AX染色来评估ATIC抑制或消除对细胞DNA损伤反应的影响。在多种癌细胞系的克隆存活测定中，ATIC 的消耗或其转化酰酶活性的抑制显着降低了细胞的存活分数。在没有电离辐射暴露的情况下，ATIC 敲低或化学抑制会激活细胞周期检查点，将细胞转移到细胞周期对辐射更敏感的 G2/M 期，并耗尽细胞 ATP，但不会导致可检测到的 DNA 损伤。与经过辐射但未经其他处理的对照相比，敲低或抑制 ATIC 然后用电离辐射处理的细胞显示出 DNA 双链断裂 (DSB) 数量增加，并且这些断裂的修复延迟。培养基中添加外源 ATP 可改善 DNA 修复表型。这些发现表明 ATIC 是一种有效且之前未被认识的放化疗增敏靶标，更广泛地表明细胞中的嘌呤水平在调节 DNA 损伤反应效率方面可能具有未被充分认识的作用，而这种作用可用于放疗增敏策略。
Mutations in the gene encoding 5-aminoimidazole-4-carboxamide ribonucleotide formyltransferase/IMP cyclohydrolase (ATIC), a bifunctional enzyme that catalyzes the final two steps of the purine de novo biosynthetic pathway, were identified in a subject referred for radiation sensitivity testing. Functional studies were carried out to determine if ATIC inhibition was radiosensitizing, and if so, to elucidate the mechanism of this effect and to determine if small molecule inhibitors of ATIC could act as effective radiosensitizing agents. Both siRNA knockdown and small molecule inhibitors were used to inactivate ATIC in cell culture. Clonogenic survival assays, the neutral comet assay, and γH2AX staining were used to assess the effects of ATIC inhibition or depletion on cellular DNA damage responses. Depletion of ATIC or inhibition of its transformylase activity significantly reduced the surviving fraction of cells in clonogenic survival assays in multiple cancer cell lines. In the absence of ionizing radiation exposure, ATIC knockdown or chemical inhibition activated cell cycle checkpoints, shifting cells to the more radiosensitive G2/M phase of the cell cycle, and depleted cellular ATP, but did not result in detectable DNA damage. Cells in which ATIC was knocked down or inhibited and then treated with ionizing radiation displayed increased numbers of DNA double-strand breaks (DSBs), and a delay in the repair of those breaks relative to irradiated, but otherwise untreated, controls. Supplementation of culture media with exogenous ATP ameliorated the DNA repair phenotypes. These findings implicate ATIC as an effective, and previously unrecognized, target for chemoradiosensitization and more broadly suggest that purine levels in cells may have an underappreciated role in modulating the efficiency of DNA damage responses that could be exploited in radiosensitizing strategies.
登录
查看更多内容
DOI：
10.1186/1748-717x-6-144
发表时间：
2011-10-26
期刊：
Radiation oncology (London, England)
影响因子：
--
作者：
Rashid A;Liu C;Sanli T;Tsiani E;Singh G;Bristow RG;Dayes I;Lukka H;Wright J;Tsakiridis T
通讯作者：
Tsakiridis T
DOI：
10.1016/j.ijrobp.2011.06.1964
发表时间：
2011-12-01
影响因子：
7
作者：
Isebaert, Sofie F.;Swinnen, Johannes V.;Haustermans, Karin M.
通讯作者：
Haustermans, Karin M.
影响因子：
9
作者：
通讯作者：
--
DOI：
10.1016/j.ijrobp.2009.02.057
发表时间：
2009-08-01
影响因子：
7
作者：
Pollard, Julianne M.;Gatti, Richard A.
通讯作者：
Gatti, Richard A.
DOI：
10.1016/0304-4165(96)00021-9
发表时间：
1996-06-04
影响因子：
3
作者：
Henin, N;Vincent, MF;VandenBerghe, G
通讯作者：
VandenBerghe, G