Characterization of an NBS1C-terminal peptide that can inhibit ataxia telangiectasia mutated (ATM)-mediated DNA damage responses and enhance radiosensitivity
Characterization of an NBS1C-terminal peptide that can inhibit ataxia telangiectasia mutated (ATM)-mediated DNA damage responses and enhance radiosensitivity
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DOI：
10.1124/mol.107.036681
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发表时间：
2007-08-01
影响因子：
3.6
通讯作者：
Xu, Bo
中科院分区：
文献类型：
--
作者：
Cariveau, Mickael J.;Tang, Xi;Xu, Bo
ATM 和 NBS1 的突变分别导致人类常染色体隐性遗传疾病毛细血管扩张性共济失调和奈梅亨断裂综合征 (NBS)，它们是细胞对电离辐射 (IR) 诱导的 DNA 损伤反应的重要元素。 ATM 是磷脂酰肌醇 3 激酶家族的成员，并以 NBS1 依赖性方式被 IR 激活。 NBS1 的极端 C 末端包含一个进化上保守的序列基序，该基序对于 IR 后 ATM 的结合和激活至关重要。 ATM 磷酸化一系列靶标以启动细胞周期停滞并促进细胞存活以应对 DNA 损伤。因此，针对NBS1-ATM相互作用可能会带来一种特异性ATM抑制和放射增敏的新方法。我们开发了含有 NBS1 保守 C 端序列的小肽，以研究这些肽是否可以干扰 DNA 损伤途径。我们发现野生型 NBS1 抑制肽 (wtNIP) 可以在存在或不存在 IR 的情况下消除 NBS1-ATM 关联。我们还发现，与用对照肽处理的细胞相比，暴露于 wtNIP 的细胞表现出辐射诱导的 γ-H2AX 和 NBS1 病灶形成显着减少，表明 wtNIP 对 ATM 具有很强的抑制作用。 wtNIP 的抑制作用还会导致响应 IR 的克隆形成存活率显着下降。此外，wtNIP 不会使 ATM 有缺陷的细胞放射敏感，这表明 ATM 具有特异性抑制作用。总之，这些数据为使用 NBS1 C 端小肽作为特异性 ATM 抑制剂和放射增敏剂提供了原理证明。
ATM and NBS1, mutation of which lead to the human autosomal recessive diseases ataxia telangiectasia and Nijmegen breakage syndrome (NBS), respectively, are essential elements in the cellular response to DNA damage induced by ionizing radiation (IR). ATM is a member of the phosphatidylinositol 3-kinase family and is activated by IR in an NBS1-dependent manner. The extreme C terminus of NBS1 contains an evolutionarily conserved sequence motif that is critical for binding to and activation of ATM after IR. ATM phosphorylates a series of targets to initiate cell cycle arrest and promote cell survival in response to DNA damage. Therefore, targeting the NBS1-ATM interaction may lead to a novel approach for specific ATM inhibition and radiosensitization. We developed small peptides containing the conserved C-terminal sequence of NBS1 to investigate whether these peptides can interfere with the DNA damage pathway. We found that wild-type NBS1 inhibitory peptides (wtNIP) can abrogate NBS1-ATM association in the presence or absence of IR. We also found that cells exposed to wtNIP displayed a significant reduction in radiation-induced gamma-H2AX and NBS1 focus formation compared with cells treated with control peptides, demonstrating that wtNIP possesses a strong inhibitory effect on ATM. The inhibitory effect of wtNIP also leads to a significant decrease in clonogenic survival in response to IR. Furthermore, wtNIP does not radiosensitize cells with defective ATM, suggesting a specific inhibition of ATM. Together, these data provide a proof of principle for the use of NBS1 C-terminal small peptides as specific ATM inhibitors and radiosensitizers.