Genomic Instability Group, Spanish National Cancer Research Centre, Madrid, Spain.
Nat Struct Mol Biol. 2011 Jun;18(6):721-7. doi: 10.1038/nsmb.2076. Epub 2011 May 8.
Oncogene activation has been shown to generate replication-born DNA damage, also known as replicative stress. The primary responder to replicative stress is not Ataxia-Telangiectasia Mutated (ATM) but rather the kinase ATM and Rad3-related (ATR). One limitation for the study of ATR is the lack of potent inhibitors. We here describe a cell-based screening strategy that has allowed us to identify compounds with ATR inhibitory activity in the nanomolar range. Pharmacological inhibition of ATR generates replicative stress, leading to chromosomal breakage in the presence of conditions that stall replication forks. Moreover, ATR inhibition is particularly toxic for p53-deficient cells, this toxicity being exacerbated by replicative stress-generating conditions such as the overexpression of cyclin E. Notably, one of the compounds we identified is NVP-BEZ235, a dual phosphatidylinositol-3-OH kinase (PI3K) and mTOR inhibitor that is being tested for cancer chemotherapy but that we now show is also very potent against ATM, ATR and the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs).
癌基因激活已被证明会产生复制起源的 DNA 损伤，也称为复制应激。对复制应激的主要反应不是共济失调毛细血管扩张突变（ATM），而是 ATM 和 Rad3 相关激酶（ATR）。ATR 研究的一个限制因素是缺乏有效的抑制剂。我们在这里描述了一种基于细胞的筛选策略，该策略使我们能够在纳摩尔范围内识别具有 ATR 抑制活性的化合物。ATR 的药理学抑制会产生复制应激，导致在复制叉停滞的情况下产生染色体断裂。此外，ATR 抑制对 p53 缺陷细胞特别有毒，这种毒性会因复制应激产生条件（如 cyclin E 的过表达）而加剧。值得注意的是，我们鉴定出的一种化合物是 NVP-BEZ235，一种双重磷脂酰肌醇-3-羟激酶（PI3K）和 mTOR 抑制剂，目前正在进行癌症化疗测试，但我们现在发现它对 ATM、ATR 和 DNA 依赖性蛋白激酶（DNA-PKcs）的催化亚基也非常有效。
