ANALYSIS OF HISTONE DEMETHYLASE ACTIVITY IN HYPOXIC CANCER CELLS

这个子项目是利用资源的许多研究子项目之一。 由NIH/NCRR资助的中心拨款提供。对子项目的主要支持 子项目的首席调查员可能是由其他来源提供的， 包括美国国立卫生研究院的其他来源。为子项目列出的总成本可能 表示该子项目使用的中心基础设施的估计数量， 不是由NCRR赠款提供给次级项目或次级项目工作人员的直接资金。 肿瘤内不受控制的细胞生长会导致缺氧，因为细胞的新陈代谢需求超过了肿瘤血管提供氧气和营养的能力。作为对低氧微环境的反应，细胞经历了大规模的转录重新编程以促进生存。低氧诱导转录因子(HIF)是低氧反应的主要调节因子，可诱导多种转录-垂体调节因子的表达，包括几种组蛋白去甲基酶，为低氧细胞延长或固定有利于生存的基因的表达提供了机制。其中一个组蛋白去甲基酶JMJD2B(KDM4B)去甲基化了组蛋白H3赖氨酸9(H3K9me3)，这是抑制染色质结构的关键标志。KDM4B的低氧诱导可能在激活基因表达以促进肿瘤生长方面发挥重要作用，因此成为新化疗药物开发的一个有吸引力的靶点。在这项提案中，JMJD2B调节肿瘤生长的程度将通过以下方式进行测试： 1.体内使用肿瘤异种移植实验(特异靶1、亚靶1) 2.体外检测JMJD2B表达对细胞增殖、侵袭和血管生成的影响(特异靶1、亚靶2)。 3.表达谱芯片实验将发现JMJD2B在低氧条件下调控的新基因。 4.染色质免疫沉淀将表征对肿瘤形成表型重要的基因的关键通路的调节(特定目标2)。 该提案中描述的实验将建立JMJD2B用来调控肿瘤发生的机制，同时确定以增强肿瘤治疗为靶点的新途径。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Uncontrolled cell growth within a tumor results in hypoxia as the metabolic needs of the cells exceed the ability of the tumor vasculature to provide oxygen and nutrients. In response to the hypoxic microenvironment, cells undergo a massive reprogramming of transcription to promote survival. The Hypoxia Inducible Transcription Factors (HIFs) are primary regulators of the hypoxic response and induce expression of several transcripitonal regulators, including several histone demethylases, providing a mechanism for the hypoxic cell to extend or fix the expression of pro-survival genes. One of these histone demethylases, JMJD2B (KDM4B), demethylates tri-methylated histone H3 lysine 9 (H3K9me3) a key marker of repressed chromatin structure. Hypoxic induction of KDM4B may play an important role in activating gene expression to promote tumor growth, and therefore makes an attractive target for the development of new chemotherapeutic agents. In this proposal, the extent to which JMJD2B regulates tumor growth will be tested in the following manner: 1. In vivo using tumor xenograft experiments (Specific Aim 1, Sub-aim 1) 2. In vitro by assaying for cell proliferation, invasion, and angiogenesis as a result of JMJD2B expression (Specific Aim 1, sub-aim 2). 3. Expression microarray experiments will identify new genes regulated by JMJD2B in hypoxia. 4. Chromatin immunoprecipitation will characterize the regulation of key pathways of genes important for the tumorigenic phenotype (Specific Aim 2). The experiments described in this proposal will establish the mechanisms utilized by JMJD2B to regulate tumorigenesis, while identifying new pathways to target for enhanced tumor therapies.