Cancer cells utilize self-inflicted DNA breaks to evade growth limits imposed by exogenous genotoxic stress. Cancer cells utilize self-inflicted DNA breaks to evade growth limits imposed by exogenous genotoxic stress

Exposure to genotoxic challenge activates cell cycle checkpoints to prevent progression and propagation of deleterious DNA damage. We identify the activity of a nuclease, Caspase-activated DNase (CAD), in promoting G2 checkpoint control in cancer cells via the infliction of DNA breaks. To appreciate the genomic context of these breaks, we performed (genome wide ligation of 3’-hydroxy (OH) ends followed by sequencing), to map the endogenously inflicted DNA breaks following irradiation. Overall design: GLOE-seq on HCT116 wildtype and CAD-/- cells: Untreated (UT), 20 min post-IR and 24 h post-IR. IR dosage: total of 8Gy given at a dosage rate of 1Gy/min.

暴露于遗传毒性应激可激活细胞周期检验点，以阻断有害DNA损伤的进展与扩散。我们鉴定出一种核酸酶——半胱天冬酶激活的脱氧核糖核酸酶（Caspase-activated DNase, CAD），可通过诱导DNA断裂在癌细胞中促进G2期检验点调控。为解析此类断裂的基因组背景，我们采用3’羟基末端全基因组连接后测序（Genome-wide ligation of 3’-hydroxy ends followed by sequencing）的方法，对辐照后内源产生的DNA断裂进行定位。实验整体设计：对HCT116野生型与CAD基因敲除（CAD-/-）细胞开展GLOE-seq实验，设置未处理组（Untreated, UT）、辐照后20分钟组及辐照后24小时组三个组别。辐照总剂量为8Gy，剂量率为1Gy/分钟。