Insulin-like growth factor I receptor regulates the radiation-induced G2/M checkpoint in HeLa cells
Insulin-like growth factor I receptor regulates the radiation-induced G2/M checkpoint in HeLa cells
复制标题
DOI：
10.1016/j.bbrc.2018.08.080
复制
发表时间：
2018-09-18
影响因子：
3.1
通讯作者：
Miura, Masahiko
中科院分区：
文献类型：
--
作者：
Manila, Nisha Gowri;Kaida, Atsushi;Miura, Masahiko
胰岛素样生长因子I受体（IGF-IR）在细胞生长、转化、存活和DNA修复等生物学过程中起着关键作用。在这项研究中，我们探讨了它可能参与细胞周期检查点，使用HeLa细胞表达荧光泛素化为基础的细胞周期指标（Fucci）。我们发现，IGF-IR抑制剂延迟释放辐射诱导的G2期阻滞，如Fucci荧光的FACS和谱系分析所示。延长的G2期阻滞也被磷脂酰肌醇-3激酶（P13 K）和AKT的抑制剂诱导，但不是由MEK的抑制剂，这是两个主要的IGF-IR下游信号通路。双链断裂（DSB）修复动力学不受IGF-IR抑制剂的影响。CHK 1抑制剂消除了辐射诱导的G2期阻滞，而IGF-IR抑制剂降低了辐射诱导的CHK 1在Ser 345或Ser 296的磷酸化。然而，辐射诱导的CHK 1的核定位在IGF-IR抑制剂处理的细胞中与单独接受辐射的细胞相比延长;在后者中，CHK 1返回到原始的弥漫性分布，并从G2期阻滞释放。我们的结论是，IGF-IR直接调节G2/M检查点通过PI 3 K/AKT通路，而不影响DSB修复，部分通过控制CHK 1定位在细胞核和细胞质之间。(C)2018爱思唯尔公司All rights reserved.
Insulin-like growth factor I receptor (IGF-IR) plays pivotal roles in various biological events, including cell growth, transformation, survival, and DNA repair. In this study, we explored its possible involvement in cell cycle checkpoints, using HeLa cells expressing the fluorescent ubiquitination-based cell cycle indicator (Fucci). We found that IGF-IR inhibitor delayed release from radiation-induced G2 arrest, as demonstrated by FACS and pedigree analysis of Fucci fluorescence. Elongated G2 arrest was also induced by inhibitors of phosphatidylinositol-3 kinase (P13K) and AKT, but not by inhibitor of MEK, which are two major IGF-IR downstream signaling pathways. Double-strand break (DSB) repair kinetics were not affected by IGF-IR inhibitor. CHK1 inhibitor abrogated radiation-induced G2 arrest, whereas radiation induced phosphorylation of CHK1 at Ser 345 or Ser 296 was decreased by the IGF-IR inhibitor. However, radiation-induced nuclear localization of CHK1 was prolonged in IGF-IR inhibitor treated cells in comparison with cells that received radiation alone; in the latter, CHK1 returned to the original diffuse distribution in conjunction with release from G2 arrest. We conclude that IGF-IR directly regulates the G2/M checkpoint via the PI3K/AKT pathway without influencing DSB repair, in part by controlling CHK1 localization between the nucleus and cytoplasm. (C) 2018 Elsevier Inc. All rights reserved.