Activation of Bmp2-Smad1 signal and its regulation by coordinated alteration of H3K27 trimethylation in Ras-induced senescence.
Activation of Bmp2-Smad1 signal and its regulation by coordinated alteration of H3K27 trimethylation in Ras-induced senescence.
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DOI：
10.1371/journal.pgen.1002359
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发表时间：
2011-11
期刊：
影响因子：
4.5
通讯作者：
Aburatani H
中科院分区：
文献类型：
--
作者：
Kaneda A;Fujita T;Anai M;Yamamoto S;Nagae G;Morikawa M;Tsuji S;Oshima M;Miyazono K;Aburatani H
细胞衰老涉及表观遗传改变，例如Ink 4a-Arf基因座中H3 K27 me 3的丢失。使用小鼠胚胎成纤维细胞（MEF），我们在这里分析了转录和表观遗传学的改变在Ras诱导的衰老在全基因组范围内的染色质免疫沉淀（ChIP）测序和微阵列。Bmp 2是最活跃的分泌因子，H3 K4 me 3获得和H3 K27 me 3丢失，而H3 K4 me 3丢失和H3 K27 me 3的从头形成在9个基因的抑制中相反地发生，包括两个BMP-SMAD抑制剂Smad 6和Noggin。不太可能发生DNA甲基化改变。Ras激活的细胞衰老，磷酸化SMAD 1/5/8的核积累。当Bmp 2/Smad 1信号被Bmp 2敲低、Smad 6诱导或Noggin诱导阻断时，Ras激活的细胞中的衰老被绕过。当将重组BMP 2蛋白加入Bmp 2敲低Ras活化的细胞中时，诱导衰老。然后在暴露于BMP 2的MEF中使用抗Smad 1抗体通过ChIP测序对下游Bmp 2-Smad 1靶基因进行全基因组分析。Smad 1靶位点在基因转录起始位点附近富集，这与BMP 2刺激的上调显著相关。虽然Smad 6是通过BMP 2暴露上调的Smad 1靶基因之一，但Ras活化细胞中的Smad 6抑制增加了Ezh 2的富集和H3 K27 me 3的获得，表明Polycomb对负反馈的表观遗传破坏。在Ras激活的细胞中上调的Smad 1靶基因中，没有增加的抑制标记，发现Parvb有助于生长抑制，因为Parvb敲低导致逃避衰老。本研究通过全基因组分析揭示了Bmp 2-Smad 1信号及其通过协调表观基因组改变的调节在Ras诱导的衰老中起重要作用。为了避免成为癌细胞，细胞有一个屏障系统，通过陷入不可逆的生长停滞来阻止细胞增殖，即所谓的细胞衰老。对于未来的癌症治疗策略，重要的是要了解癌症是如何发生的，而衰老的潜在机制的研究可以导致癌症发生机制的澄清。DNA甲基化和组蛋白修饰等表观遗传机制可能对衰老过程中基因表达的调节起重要作用。在这里，利用最新的技术和方法进步的全基因组分析，我们研究表观基因组和基因表达的Ras癌基因诱导的衰老改变。我们确定Bmp 2-Smad 1信号是关键的。我们进一步在全基因组范围内研究了这一关键信号的下游靶基因。我们显示了动态和协调的H3 K27 me 3改变，例如通过H3 K27 me 3的丢失激活Bmp 2，通过H3 K27 me 3的获得抑制信号抑制剂和负反馈环，以及选择性激活可能有助于生长停滞的下游靶基因。我们的研究结果有助于理解表观遗传调控的重要性，以及BMP-SMAD信号在癌症中的重要性，以及Ras突变的癌症如何发生。
Cellular senescence involves epigenetic alteration, e.g. loss of H3K27me3 in Ink4a-Arf locus. Using mouse embryonic fibroblast (MEF), we here analyzed transcription and epigenetic alteration during Ras-induced senescence on genome-wide scale by chromatin immunoprecipitation (ChIP)-sequencing and microarray. Bmp2 was the most activated secreted factor with H3K4me3 gain and H3K27me3 loss, whereas H3K4me3 loss and de novo formation of H3K27me3 occurred inversely in repression of nine genes, including two BMP-SMAD inhibitors Smad6 and Noggin. DNA methylation alteration unlikely occurred. Ras-activated cells senesced with nuclear accumulation of phosphorylated SMAD1/5/8. Senescence was bypassed in Ras-activated cells when Bmp2/Smad1 signal was blocked by Bmp2 knockdown, Smad6 induction, or Noggin induction. Senescence was induced when recombinant BMP2 protein was added to Bmp2-knocked-down Ras-activated cells. Downstream Bmp2-Smad1 target genes were then analyzed genome-wide by ChIP-sequencing using anti-Smad1 antibody in MEF that was exposed to BMP2. Smad1 target sites were enriched nearby transcription start sites of genes, which significantly correlated to upregulation by BMP2 stimulation. While Smad6 was one of Smad1 target genes to be upregulated by BMP2 exposure, Smad6 repression in Ras-activated cells with increased enrichment of Ezh2 and gain of H3K27me3 suggested epigenetic disruption of negative feedback by Polycomb. Among Smad1 target genes that were upregulated in Ras-activated cells without increased repressive mark, Parvb was found to contribute to growth inhibition as Parvb knockdown lead to escape from senescence. It was revealed through genome-wide analyses in this study that Bmp2-Smad1 signal and its regulation by harmonized epigenomic alteration play an important role in Ras-induced senescence. To avoid becoming cancer cells, cells have a barrier system to block cellular proliferation by falling into irreversible growth arrest, so-called cellular senescence. For future strategy of cancer treatment, it is important to understand how cancer occurs, and investigation of underlying mechanism in senescence can lead to clarification of carcinogenesis mechanism. Epigenetic mechanism including DNA methylation and histone modification may be important to regulate gene expressions properly in senescence. Here, taking advantage of recent technical and methodological advance of genome-wide analyses, we examine epigenome and gene expression alteration in senescence induced by Ras oncogene. We identify that Bmp2-Smad1 signal is critical. We further examine downstream target genes of this critical signal on a genome-wide scale. We show dynamic and coordinated H3K27me3 alteration, e.g. activation of Bmp2 by loss of H3K27me3, repression of the signal inhibitors and the negative feedback loop by gain of H3K27me3, and selective activation of downstream target genes that may contribute to growth arrest. Our findings are helpful in understanding the importance of epigenetic regulation and a critical signal in the physiological barrier system against oncogenic transformation and the importance of disruption of BMP-SMAD signal in cancer, and they may provide an idea how cancer with Ras mutation occurs.
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影响因子：
10.5
作者：
Barradas, Marta;Anderton, Emma;Gil, Jesus
通讯作者：
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影响因子：
10.5
作者：
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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：
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5.7
作者：
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通讯作者：
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癌基因诱导的DNA损伤反应与衰老和癌症异染色质之间的相互作用。
影响因子：
21.3
作者：
Di Micco R;Sulli G;Dobreva M;Liontos M;Botrugno OA;Gargiulo G;dal Zuffo R;Matti V;d'Ario G;Montani E;Mercurio C;Hahn WC;Gorgoulis V;Minucci S;d'Adda di Fagagna F
通讯作者：
d'Adda di Fagagna F