Regulation of p53 and Rb links the alternative NF-κB pathway to EZH2 expression and cell senescence.
Regulation of p53 and Rb links the alternative NF-κB pathway to EZH2 expression and cell senescence.
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DOI：
10.1371/journal.pgen.1004642
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发表时间：
2014-09
期刊：
影响因子：
4.5
通讯作者：
Perkins ND
中科院分区：
文献类型：
--
作者：
Iannetti A;Ledoux AC;Tudhope SJ;Sellier H;Zhao B;Mowla S;Moore A;Hummerich H;Gewurz BE;Cockell SJ;Jat PS;Willmore E;Perkins ND
诱导NF-κB亚基的途径主要有两种。经典（或规范）途径通常导致RelA或含c-Rel复合物的诱导，并以依赖于IκB激酶(IKK) β和IKK调控亚基NEMO的方式涉及IκBα的降解。另一种（或非典型）途径包括p100到p52的诱导加工，导致NF-κB2(p52)/RelB复合物的诱导，并依赖于IKKα和NF-κB诱导激酶（NIK）。本研究表明，在原代人成纤维细胞中，可选择的NF-κB途径亚基NF-κB2和RelB对细胞周期、活性氧（ROS）生成和蛋白质稳定性的关键调节因子的表达具有多种但不同的影响。具体来说，在siRNA敲除后，定量PCR、western blot分析和染色质免疫沉淀（ChIP）显示NF-κB2调控CDK4和CDK6的表达，而RelB通过调控PSMA5和ANAPC1等基因调控p21WAF1和肿瘤抑制因子p53的稳定性。这些结合起来调节视网膜母细胞瘤蛋白Rb的活性，导致诱导多梳蛋白EZH2的表达。此外，我们的ChIP分析表明EZH2也是NF-κB的直接靶基因。微阵列分析显示，在成纤维细胞中，EZH2拮抗先前与衰老细胞表型相关的p53靶基因亚群，包括DEK和RacGAP1。我们发现这条通路提供了NF-κB通路和p53之间的主要串扰途径，其结果是抑制细胞衰老。重要的是，我们发现NF-κB的激活也诱导了慢性淋巴细胞白血病患者CD40L刺激细胞中EZH2的表达。因此，我们认为这一途径提供了微环境诱导的NF-κB抑制肿瘤抑制功能并促进肿瘤发生的机制。尽管经典的NF-κB通路经常与细胞衰老和衰老相关分泌表型（senescence associated secretory phenotype， SASP）的诱导有关，但在血液系统恶性肿瘤和一些实体肿瘤中经常被激活的另一种NF-κB通路的作用尚未明确。因此，我们研究了NF-κB通路在这一过程中的作用。在这里，我们报道NF-κB2和RelB， NF-κB替代途径的效应物，通过抑制p53活性来抑制衰老。使用原代人成纤维细胞，我们证明这是通过NF-κB2/RelB依赖性控制先前未知的途径实现的，包括调节CDK4和6的表达以及调节p21WAF1和p53蛋白的稳定性。NF-κB2/RelB的缺失导致视网膜母细胞瘤（Rb）肿瘤抑制因子磷酸化的抑制，进而导致EZH2表达的抑制和p53活性的去抑制。有趣的是，我们发现CD40配体刺激慢性淋巴细胞白血病患者细胞，强烈诱导NF-κB替代通路，也诱导EZH2表达。我们认为NF-κB通路可以通过抑制p53依赖性衰老来促进肿瘤发生，这一过程可能与癌细胞保留野生型p53有关。
There are two major pathways leading to induction of NF-κB subunits. The classical (or canonical) pathway typically leads to the induction of RelA or c-Rel containing complexes, and involves the degradation of IκBα in a manner dependent on IκB kinase (IKK) β and the IKK regulatory subunit NEMO. The alternative (or non-canonical) pathway, involves the inducible processing of p100 to p52, leading to the induction of NF-κB2(p52)/RelB containing complexes, and is dependent on IKKα and NF-κB inducing kinase (NIK). Here we demonstrate that in primary human fibroblasts, the alternative NF-κB pathway subunits NF-κB2 and RelB have multiple, but distinct, effects on the expression of key regulators of the cell cycle, reactive oxygen species (ROS) generation and protein stability. Specifically, following siRNA knockdown, quantitative PCR, western blot analyses and chromatin immunoprecipitation (ChIP) show that NF-κB2 regulates the expression of CDK4 and CDK6, while RelB, through the regulation of genes such as PSMA5 and ANAPC1, regulates the stability of p21WAF1 and the tumour suppressor p53. These combine to regulate the activity of the retinoblastoma protein, Rb, leading to induction of polycomb protein EZH2 expression. Moreover, our ChIP analysis demonstrates that EZH2 is also a direct NF-κB target gene. Microarray analysis revealed that in fibroblasts, EZH2 antagonizes a subset of p53 target genes previously associated with the senescent cell phenotype, including DEK and RacGAP1. We show that this pathway provides the major route of crosstalk between the alternative NF-κB pathway and p53, a consequence of which is to suppress cell senescence. Importantly, we find that activation of NF-κB also induces EZH2 expression in CD40L stimulated cells from Chronic Lymphocytic Leukemia patients. We therefore propose that this pathway provides a mechanism through which microenvironment induced NF-κB can inhibit tumor suppressor function and promote tumorigenesis. Although the classical NF-κB pathway is frequently associated with the induction of cellular senescence and the senescence associated secretory phenotype (SASP), the role of the alternative NF-κB pathway, which is frequently activated in hematological malignancies as well as some solid tumors, has not been defined. We therefore investigated the role of the alternative NF-κB pathway in this process. Here we report that NF-κB2 and RelB, the effectors of the alternative NF-κB pathway, suppress senescence through inhibition of p53 activity. Using primary human fibroblasts, we demonstrate that this is accomplished through NF-κB2/RelB dependent control of a previously unknown pathway, incorporating regulation of CDK4 and 6 expression as well as regulators of p21WAF1 and p53 protein stability. Loss of NF-κB2/RelB results in suppression of retinoblastoma (Rb) tumour suppressor phosphorylation, which in turn leads to inhibition of EZH2 expression and de-repression of p53 activity. Interestingly, we find that CD40 ligand stimulation of cells from Chronic Lymphocytic Leukemia patients, which strongly induces the alternative NF-κB pathway, also induces EZH2 expression. We propose that the alternative NF-κB pathway can promote tumorigenesis through suppression of p53 dependent senescence, a process that may have relevance to cancer cells retaining wild type p53.
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影响因子：
14.9
作者：
Kavanaugh GM;Wise-Draper TM;Morreale RJ;Morrison MA;Gole B;Schwemberger S;Tichy ED;Lu L;Babcock GF;Wells JM;Drissi R;Bissler JJ;Stambrook PJ;Andreassen PR;Wiesmüller L;Wells SI
通讯作者：
Wells SI
影响因子：
3.3
作者：
Freund A;Laberge RM;Demaria M;Campisi J
通讯作者：
Campisi J
影响因子：
12.3
作者：
Gentleman RC;Carey VJ;Bates DM;Bolstad B;Dettling M;Dudoit S;Ellis B;Gautier L;Ge Y;Gentry J;Hornik K;Hothorn T;Huber W;Iacus S;Irizarry R;Leisch F;Li C;Maechler M;Rossini AJ;Sawitzki G;Smith C;Smyth G;Tierney L;Yang JY;Zhang J
通讯作者：
Zhang J
影响因子：
5.8
作者：
Keutgens, Aurore;Robert, Isabelle;Chariot, Alain
通讯作者：
Chariot, Alain
DOI：
10.1073/pnas.92.20.9363
发表时间：
1995-09-26
影响因子：
11.1
作者：
DIMRI, GP;LEE, XH;CAMPISI, J
通讯作者：
CAMPISI, J