Radiosensitization by the ATR Inhibitor AZD6738 through Generation of Acentric Micronuclei.
Radiosensitization by the ATR Inhibitor AZD6738 through Generation of Acentric Micronuclei.
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DOI：
10.1158/1535-7163.mct-16-0239
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发表时间：
2017-01
影响因子：
5.7
通讯作者：
Harrington KJ
中科院分区：
文献类型：
--
作者：
Dillon MT;Barker HE;Pedersen M;Hafsi H;Bhide SA;Newbold KL;Nutting CM;McLaughlin M;Harrington KJ
AZD6738是一种口服活性ATR抑制剂（ATRi），目前处于I期临床试验。我们在一组人类癌细胞系中发现了该ATRi的体外生长抑制活性。我们通过克隆实验证明AZD6738对多种癌细胞系的单一辐射组分具有放射增敏作用，这些癌细胞系与p53和BRCA2状态无关。AZD6738在体外通过三维肿瘤球体模型证明了对临床相关剂量的分次辐射的放射致敏性，在体内，AZD6738通过取消辐射诱导的G2细胞周期检查点和抑制同源重组来实现放射致敏。DNA受损的有丝分裂导致有丝分裂灾难，通过活细胞荧光-泛素化的微核形成来测量细胞周期进程和核形态的细胞周期成像。与单独抑制下游激酶CHK1相比，AZD6738在等有效剂量下对微核的诱导作用更为显著。微核的特征是染色体片段无中心，与初代核相比，微核表现出DNA损伤增加和细胞周期不同步的特征。
AZD6738 is an orally active ATR inhibitor (ATRi) currently in phase I clinical trials. We found in vitro growth inhibitory activity of this ATRi in a panel of human cancer cell lines. We demonstrated radiosensitization by AZD6738 to single radiation fractions in multiple cancer cell lines independent of both p53 and BRCA2 status by the clonogenic assay. Radiosensitization by AZD6738 to clinically relevant doses of fractionated radiation was demonstrated in vitro using a 3D tumor spheroid model and, in vivo, AZD6738 radiosensitized by abrogating the radiation-induced G2 cell-cycle checkpoint and inhibiting homologous recombination. Mitosis with damaged DNA resulted in mitotic catastrophe as measured by micronucleus formation by live-cell fluorescent-ubiquitination cell-cycle imaging of cell-cycle progression and nuclear morphology. Induction of micronuclei was significantly more prominent for AZD6738 compared with inhibition of the downstream kinase CHK1 alone at isoeffective doses. Micronuclei were characterized as acentric chromosomal fragments, which displayed characteristics of increased DNA damage and cell-cycle dyssynchrony when compared with the primary nucleus.