siRNA targeting NBS1 or XIAP increases radiation sensitivity of human cancer cells independent of TP53 status
siRNA targeting NBS1 or XIAP increases radiation sensitivity of human cancer cells independent of TP53 status
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DOI：
10.1667/rr3606.1
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发表时间：
2006-09-01
影响因子：
3.4
通讯作者：
Ohnishi, Takeo
中科院分区：
文献类型：
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作者：
Ohnishi, Ken;Scuric, Zorica;Ohnishi, Takeo
NBS 1是酵母和高等脊椎动物细胞中辐射诱导的DNA双链断裂（DSB）修复所必需的。在这项研究中，我们研究了通过小干扰RNA（siRNA）抑制NBS 1表达是否可以增强具有不同TP 53状态的癌细胞的辐射敏感性。我们使用TP 53基因状态不同的人非小细胞肺癌细胞（携带野生型TP 53的H1299/wtp 53细胞或携带突变型TP 53的H1299/mp53细胞）。将表达靶向NBS 1基因的siRNA的DNA盒转染到这些细胞系中，并用集落形成测定法检查辐射敏感性。使用蛋白质印迹法分析NBS 1和其他蛋白质的细胞水平。我们发现，通过转染DNA盒，H1299/wtp 53和H1299/mp53细胞的辐射敏感性增强。在NBS 1-siRNA转染的细胞中，我们观察到NBS 1蛋白的组成性表达减少，并且减少了辐射诱导的磷酸化NBS 1蛋白的积累。此外，辐射诱导的转录因子NF-κ B（NF κ B）和XIAP（X染色体连锁凋亡抑制蛋白）的表达被NBS 1-siRNA抑制。NBS 1-siRNA转染后，在TP 53野生型细胞中实现了增强的X射线敏感性，并且在TP 53突变细胞中的敏感性甚至更明显。与TP 53野生型细胞相比，靶向XIAP的siRNA的转染也增强了TP 53突变细胞的X射线敏感性。我们的数据表明，对辐射的敏感性是由NBS 1-siRNA介导的DNA修复抑制和/或X射线诱导的细胞存活信号通路通过NF κ B和XIAP引起的。siRNA靶向似乎是一种新的辐射增敏剂，特别是在人TP 53突变癌细胞中。(c)2006年，辐射研究协会。
NBS1 is essential for the repair of radiation-induced DNA double-strand breaks (DSBs) in yeast and higher vertebrate cells. In this study, we examined whether suppressed NBS1 expression by small interference RNA (siRNA) could enhance radiation sensitivity in cancer cells with different TP53 status. We used human non-small cell lung cancer cells differing in TP53 gene status (H1299/wtp53 cells bearing wild-type TP53 or H1299/mp53 cells bearing mutant TP53). A DNA cassette expressing siRNA targeted for the NBS1 gene was transfected into those cell lines, and radiation sensitivity was examined with a colony-forming assay. Cellular levels of NBS1 and other proteins were analyzed using Western blotting. We found that the radiation sensitivity of H1299/wtp53 and H1299/mp53 cells was enhanced by transfection of the DNA cassette. In the NBS1-siRNA-transfected cells, we observed decreased constitutive expression of NBS1 protein and decreased radiation-induced accumulation of phosphorylated NBS1 protein. In addition, radiation-induced expression of the transcription factor NF-kappa B (NFKB) and XIAP (X-chromosome-linked inhibitor of apoptosis protein) was suppressed by NBS1-siRNA. Enhanced X-ray sensitivity after NBS1-siRNA transfection was achieved in TP53 wild-type cells and sensitivity was even more pronounced in TP53 mutant cells. The transfection of siRNA targeted for XIAP also enhanced X-ray sensitivity even more for TP53 mutant cells compared to TP53 wild-type cells. Our data suggest that the sensitization to radiation results from NBS1-siRNA-mediated suppression of DNA repair and/or X-ray-induced cell survival signaling pathways through NFKB and XIAP. siRNA targeting appears to be a novel radiation-sensitizing agent, particularly in human TP53 mutant cancer cells. (c) 2006 by Radiation Research Society.