HDM2 antagonist Nutlin-3 disrupts p73-HDM2 binding and enhances p73 function
HDM2 antagonist Nutlin-3 disrupts p73-HDM2 binding and enhances p73 function
复制标题
DOI：
10.1038/sj.onc.1210707
复制
发表时间：
2008-02-07
期刊：
影响因子：
8
通讯作者：
Irwin, M. S.
中科院分区：
文献类型：
--
作者：
Lau, L. M. S.;Nugent, J. K.;Irwin, M. S.
Nutlin-3是一种小分子抑制剂，通过破坏p53-HDM 2结合来激活p53。在这项研究中，我们发现，Nutlin-3抑制细胞生长，诱导细胞凋亡的野生型p53的情况下，提示p53的非依赖性机制Nutlin-3诱导的细胞死亡。与p53类似，其同系物p73反式激活促凋亡基因并诱导细胞死亡。由于HDM 2是p53的关键负调节因子，也结合并抑制p73，我们询问p73是否可以介导Nutlin-3诱导的细胞凋亡。我们证明Nutlin-3抑制p53缺失细胞中促凋亡p73亚型TAp 73 α和HDM 2之间的内源性结合。p73和HDM 2的解离导致p73转录活性增加，p73靶基因noxa、puma和p21上调，以及细胞凋亡增强。通过siRNA敲低p73导致拯救Nutlin-3处理的细胞，表明Nutlin-3诱导的细胞凋亡至少部分是p73依赖性的。此外，Nutlin-3治疗增加了TAp 73 α蛋白水平，延长了p73半衰期。这些结果提供了Nutlin-3破坏内源性p73-HDM 2相互作用并增强p73的稳定性和促凋亡活性的第一个证据，从而为Nutlin-3在其中p53失活的大量人类肿瘤中的应用提供了理论基础。
Nutlin-3, a small molecule inhibitor, activates p53 by disrupting p53-HDM2 association. In this study, we found that Nutlin-3 suppressed cell growth and induced apoptosis in the absence of wild-type p53, suggesting a p53-independent mechanism for Nutlin-3-induced cell death. Like p53, its homolog p73 transactivates proapoptotic genes and induces cell death. Since HDM2, a key negative regulator of p53, also binds to and inhibits p73, we asked whether p73 could mediate Nutlin-3-induced apoptosis. We demonstrate that Nutlin-3 inhibits endogenous binding between the proapoptotic p73 isoform TAp73 alpha and HDM2 in p53-null cells. Dissociation of p73 and HDM2 leads to increased p73 transcriptional activity with up regulation of p73 target genes noxa, puma and p21,as well as enhanced apoptosis. p73 knockdown by siRNA results in rescue of Nutlin-3-treated cells, indicating that Nutlin-3-induced apoptosis is, at least in part, p73 dependent. In addition, Nutlin-3 treatment increases TAp73 alpha protein levels with prolongation of p73 half-life. These results provide the first evidence that Nutlin-3 disrupts endogenous p73-HDM2 interaction and enhances the stability and proapoptotic activities of p73 and thus, provides a rationale for the use of Nutlin-3 in the large number of human tumors in which p53 is inactivated.