KU70/80, DNA-PKcs, and Artemis are essential for the rapid induction of apoptosis after massive DSB formation
KU70/80, DNA-PKcs, and Artemis are essential for the rapid induction of apoptosis after massive DSB formation
复制标题
DOI：
10.1016/j.cellsig.2008.07.006
复制
发表时间：
2008-11-01
影响因子：
4.8
通讯作者：
Seki, Masayuki
中科院分区：
文献类型：
--
作者：
Abe, Takuya;Ishiai, Masamichi;Seki, Masayuki
据报道，KU70（-/-）和DNA- pkcs（-/-/-）鸡DT40细胞对DNA拓扑异构酶II抑制剂依托泊苷高度敏感。在这里，我们报道了KU70和DNA-PKcs在暴露于高水平依托泊苷后诱导细胞凋亡过程中意外地共同起作用。在100 μ M石蜡皂苷的作用下，野生型DT40细胞在1 h内诱导凋亡，而KU70（-/-）和DNA-PKcs（-/-/-）细胞未诱导凋亡。此外，DNA-PK抑制剂NU7026和wortmannin以及caspase抑制剂Z-VAD-FMK可抑制依托泊苷诱导的野生型细胞凋亡。虽然Artemis（-/-）细胞在etoposide诱导的凋亡中也表现出缺陷，但其他在非同源末端连接（NHEJ）、LIG4（-/-）、XRCC4（-）和XLF-/-细胞中存在缺陷的突变体能够诱导细胞凋亡。当细胞被高剂量依托opo苷处理时，KU70缺失而Artemis未缺失，破坏了DNA-PKcs的染色质结合，提示KU70在凋亡通路中与NHEJ通路一样作用于DNA-PKcs的上游，而Artemis则作用于DNA-PKcs的下游。这些结果表明，参与NHEJ通路早期的蛋白包括Artemis，而不是下游因子根据DNA损伤程度选择凋亡或DNA修复来决定细胞命运。(c) 2008爱思唯尔公司版权所有。
KU70(-/-) and DNA-PKcs(-/-/-)chicken DT40 cells are reportedly highly sensitive to the DNA topoisomerase II inhibitor etoposide. Here we report that KU70 and DNA-PKcs unexpectedly function together during the induction of apoptosis after exposure to high levels of etoposide. in the presence of 100 mu M etoposide, apoptosis was induced within 1 h in wild type DT40 cells but not in KU70(-/-) and DNA-PKcs(-/-/-) cells. In addition, the DNA-PK inhibitors NU7026 and wortmannin, as well as the caspase inhibitor Z-VAD-FMK, inhibited etoposide-induced apoptosis in wild type cells. Although Artemis(-/-) cells also showed defects in the etoposide-induced apoptosis, the other mutants defective in nonhomologous end-joining (NHEJ), LIG4(-/-), XRCC4(-), and XLF-/- cells were capable to induce apoptosis. When cells Were treated with high doses of etoposide, the chromatin binding of DNA-PKcs was impaired by deletion of KU70 but not of Artemis, suggesting that KU70 acts upstream of DNA-PKcs and Artemis acts downstream of DNA-PKcs in the apoptotic pathway like the NHEJ pathway. These results suggest that the proteins involved in the early stage of NHEJ pathway including Artemis but not the downstream factors decide the cell fate by selecting apoptosis or DNA repair according to the degree of DNA damage. (c) 2008 Elsevier Inc. All rights reserved.