Restricted heterochromatin formation links NFATc2 repressor activity with growth promotion in pancreatic cancer.
Restricted heterochromatin formation links NFATc2 repressor activity with growth promotion in pancreatic cancer.
复制标题
DOI：
10.1053/j.gastro.2011.11.001
复制
发表时间：
2012-02
期刊：
影响因子：
29.4
通讯作者：
Ellenrieder V
中科院分区：
文献类型：
--
作者：
Baumgart S;Glesel E;Singh G;Chen NM;Reutlinger K;Zhang J;Billadeau DD;Fernandez-Zapico ME;Gress TM;Singh SK;Ellenrieder V
p15INK4b肿瘤抑制通路的转录沉默克服了细胞对癌症无限制增殖的保护。在这里，我们展示了一种涉及致癌转录因子活化T细胞核因子（NFAT） c2的新途径，靶向p15ink4b介导的failsafe机制，促进胰腺癌肿瘤生长。免疫组织化学、实时聚合酶链反应、免疫印迹和免疫荧光显微镜用于表达研究。通过[3H]胸腺嘧啶结合、集落形成试验和体内异种移植肿瘤模型来评估肿瘤生长。通过免疫沉淀、DNA拉下、报告基因和染色质免疫沉淀分析蛋白质-蛋白质相互作用、启动子调控和局部组蛋白修饰。我们的研究揭示了NFATc2在晚期胰腺上皮内瘤变病变中的诱导作用，并在晚期癌症的肿瘤细胞核中表达增加。在细胞核中，NFATc2靶向p15INK4b启动子诱导异染色质形成和沉默。NFATc2与其同源启动子位点的结合诱导组蛋白甲基转移酶Suv39H1的逐步募集，导致局部H3K9三甲基化，并允许异染色质蛋白HP1γ与抑制因子复合物对接。相反，NFATc2的失活会破坏这种抑制因子复合物的组装和局部异染色质的形成，导致p15INK4b表达的恢复，并抑制胰腺癌在体外和体内的生长。在这里，我们描述了nfatc2介导的基因调控的新机制，并确定了其抑制因子活性、抑制因子途径p15INK4b的沉默及其胰腺癌生长调节功能之间的功能联系。因此，我们提供的证据表明，致癌性NFATc2的失活可能是治疗胰腺癌的一种有吸引力的策略。
Transcriptional silencing of the p15INK4b tumor suppressor pathway overcomes cellular protection against unrestrained proliferation in cancer. Here we show a novel pathway involving the oncogenic transcription factor nuclear factor of activated T cells (NFAT) c2 targeting a p15INK4b-mediated failsafe mechanism to promote pancreatic cancer tumor growth. Immunohistochemistry, real-time polymerase chain reaction, immunoblotting, and immunofluorescence microscopy were used for expression studies. Cancer growth was assessed in vitro by [3H]thymidine incorporation, colony formation assays, and in vivo using xenograft tumor models. Protein-protein interactions, promoter regulation, and local histone modifications were analyzed by immunoprecipitation, DNA pull-down, reporter, and chromatin immunoprecipitation assays. Our study uncovered induction of NFATc2 in late-stage pancreatic intraepithelial neoplasia lesions with increased expression in tumor cell nuclei of advanced cancers. In the nucleus, NFATc2 targets the p15INK4b promoter for inducible heterochromatin formation and silencing. NFATc2 binding to its cognate promoter site induces stepwise recruitment of the histone methyltransferase Suv39H1, causes local H3K9 trimethylation, and allows docking of heterochromatin protein HP1γ to the repressor complex. Conversely, inactivation of NFATc2 disrupts this repressor complex assembly and local heterochromatin formation, resulting in restoration of p15INK4b expression and inhibition of pancreatic cancer growth in vitro and in vivo. Here we describe a novel mechanism for NFATc2-mediated gene regulation and identify a functional link among its repressor activity, the silencing of the suppressor pathway p15INK4b, and its pancreatic cancer growth regulatory functions. Thus, we provide evidence that inactivation of oncogenic NFATc2 might be an attractive strategy in treatment of pancreatic cancer.
登录
查看更多内容
影响因子：
4.8
作者：
Singh, Shiv K.;Baumgart, Sandra;Ellenrieder, Volker
通讯作者：
Ellenrieder, Volker
影响因子：
16
作者：
Nielsen, AL;Oulad-Abdelghani, M;Losson, R
通讯作者：
Losson, R
影响因子：
64.8
作者：
Nielsen, SJ;Schneider, R;Kouzarides, T
通讯作者：
Kouzarides, T
影响因子：
3.7
作者：
Geyer, C. Ronald
通讯作者：
Geyer, C. Ronald
影响因子：
3.6
作者：
Koenig, Alexander;Fernandez-Zapico, Martin E.;Ellenrieder, Volker
通讯作者：
Ellenrieder, Volker