Nutlin-3, an Hdm2 antagonist, inhibits tumor adaptation to hypoxia by stimulating the FIH-mediated inactivation of HIF-1α
Nutlin-3, an Hdm2 antagonist, inhibits tumor adaptation to hypoxia by stimulating the FIH-mediated inactivation of HIF-1α
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DOI：
10.1093/carcin/bgp196
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发表时间：
2009-10-01
期刊：
影响因子：
4.7
通讯作者：
Park, Jong-Wan
中科院分区：
文献类型：
--
作者：
Lee, Yoon-Mi;Lim, Ji-Hong;Park, Jong-Wan
低氧诱导因子1-α(HIF-1α)、p53和人小鼠双分钟2(Hdm2)的同源基因之间的相互作用已被认为是肿瘤促进和血管生成的关键事件。最近，Hdm2的小分子拮抗剂Nutlin-3被证明可以抑制HIF-1介导的血管内皮生长因子的产生和肿瘤血管生成。然而，Nutlin-3抑制HIF-1的机制仍是一个悬而未决的问题。我们在这里讨论了Nutlin-3在HIF-1α-P53-Hdm2相互作用中的作用模式。采用报告分析、免疫沉淀和免疫印迹等方法检测Nutlin-3对HIF-1α功能的影响。Nutlin-3下调HIF-1α的表达，而HIF-1α的表达依赖于P53，但非依赖于von Hippel-Lindau。相反，Nutlin-3通过失活HIF-1来钝化缺氧诱导的血管内皮生长因子，即使在p53缺失的细胞中也是如此。Nutlin-3使HIF-1α的C末端反式激活域(CAD)失活，并且需要Asn803的因子抑制低氧诱导因子(FIH)羟化才能发挥作用。在蛋白质相互作用方面，Hdm2在CAD结合上与FIH竞争，并在体内和体外抑制Asn803羟化，从而促进p300的募集。此外，Nutlin-3通过抑制Hdm2而增强FIH结合和Ans803羟化。总之，Hdm2通过抑制FIH与CAD的相互作用而功能性地激活HIF-1，而Nutlin-3抑制Hdm2导致HIF-1失活和血管内皮生长因子抑制。HIF-1α、Hdm2、FIH和p300之间的相互作用可能成为治疗HIF-1α过表达肿瘤的潜在靶点。
The interplay among hypoxia-inducible factor 1-alpha (HIF-1 alpha), p53 and human orthologue of murine double minute 2 (Hdm2) has been introduced as a key event in tumor promotion and angiogenesis. Recently, nutlin-3, a small-molecule antagonist of Hdm2, was demonstrated to inhibit the HIF-1-mediated vascular endothelial growth factor production and tumor angiogenesis. Yet, the mechanism by which nutlin-3 inhibits HIF-1 is an open question. We here addressed the mode-of-action of nutlin-3 with respect to the HIF-1 alpha-p53-Hdm2 interplay. The effect of nutlin-3 on HIF-1 alpha function was examined by reporter analyses, immunoprecipitation and immunoblotting. Nutlin-3 downregulated HIF-1 alpha, which occurred p53-dependently but von Hippel-Lindau-independently. On the contrary, nutlin-3 blunted the hypoxic induction of vascular endothelial growth factor by inactivating HIF-1 even in p53-null cells. The C-terminal transactivation domain (CAD) of HIF-1 alpha was inactivated by nutlin-3, and furthermore, the factor-inhibiting hypoxia-inducible factor (FIH) hydroxylation of Asn803 was required for the nutlin-3 action. In terms of protein interactions, Hdm2 competed with FIH in CAD binding and inhibited the Asn803 hydroxylation both in vivo and in vitro, which facilitated p300 recruitment. Moreover, nutlin-3 reinforced the FIH binding and Ans803 hydroxylation by inhibiting Hdm2. In conclusion, Hdm2 functionally activates HIF-1 by inhibiting the FIH interaction with CAD, and the Hdm2 inhibition by nutlin-3 results in HIF-1 inactivation and vascular endothelial growth factor suppression. The interplays among HIF-1 alpha, Hdm2, FIH and p300 could be potential targets for treating tumors overexpressing HIF-1 alpha.