The Role of ING4 in Modulating the Tumorigenic Contribution of NF-kB in Gliomas

描述（由申请人提供）：恶性神经胶质瘤是一种侵袭性、高度侵袭性、神经破坏性和致命的脑肿瘤。神经胶质瘤的扩散浸润性质是患有这种癌症的患者死亡的主要原因之一。最近，神经胶质瘤的病理生物学中已经涉及到炎症反应的失调。转录因子的NF-κ B家族负责介导免疫/炎症反应，并且NF-κ B的组成性激活与胶质瘤形成相关。NF-κ B的激活通常是短暂的，并受多种机制的调节，包括与其他蛋白质的相互作用。一种这样的蛋白质，ING 4，最近已显示抑制神经胶质瘤细胞中NF-κ B介导的IL-8、IL-6和考克斯-2的表达。这种抑制可能通过ING 4和p65 NF-κ B亚型之间的相互作用发生。因此，NF-κ B途径和ING 4蛋白代表了治疗神经胶质瘤的潜在治疗靶点。我们发现ING 4对人胶质瘤细胞中NF-κ B介导的基因诱导有不同的影响，抑制IL-8的表达，但增强基质金属蛋白酶-9（MMP-9）的表达。这些结果表明ING 4对NF-κ B介导的基因的影响是复杂的，即，ING 4可以对基因表达具有积极或消极的影响，这取决于启动子环境、辅因子组成、染色质可及性和基因表达的动力学。我们认为，研究ING 4介导的调节神经胶质瘤中NF-κ B活性的分子机制是必要的，重点是ING 4调节IL-8，IL-6，MMP-9和CXCR 4的表达，所有基因都依赖于NF-κ B的活化，并参与胶质瘤的生长，侵袭和血管生成。我们将检查人类胶质瘤组织中ING 4基因的状态和完整性以及NF-κ B的激活状态，并确定是否存在相关性。将在诱导表达ING 4的人神经胶质瘤细胞中分析ING 4对NF-κ B易位到细胞核中、在体外和体内结合DNA以及调节IL-8、IL-6、MMP-9和CXCR 4的表达的能力的影响（Aim 1）。在目标2中，翻译研究将验证ING 4对体内NF-κ B介导的基因表达的影响。将诱导表达ING 4的人胶质瘤细胞移植到scid小鼠的脑中，并在体内评估ING 4表达的变化对NF-κ B活性、基因表达、胶质瘤生长、侵袭和血管生成的影响。这种基础科学实验和转化研究的结合代表了NF-KB和ING 4在胶质瘤发生中的功能参与的第一个系统性研究，并将导致对NF-KB通路和/或ING 4在恶性胶质瘤中的治疗干预潜力的更深入理解。

DESCRIPTION (provided by applicant): Malignant gliomas are an aggressive, highly invasive, neurologically destructive and deadly tumors of the brain. The diffusively infiltrative nature of gliomas is one of the major causes of mortality in patients afflicted with this cancer. Recently, dysregulation of the inflammatory response has been implicated in the pathobiology of gliomas. The NF-KB family of transcription factors are responsible for mediating immune/inflammatory responses, and constitutive activation of NF-KB has been correlated with gliomagenesis. NF-KB activation is normally transient and regulated by a variety of mechanisms, including interactions with other proteins. One such protein, ING4, has recently been shown to inhibit NF-KB-mediated expression of IL-8, IL-6 and COX-2 in glioma cells. This inhibition may occur through interactions between ING4 and the p65 NF-KB isoform. Thus, the NF-KB pathway and ING4 protein represent potential therapeutic targets for the treatment of gliomas. We have made the novel observation that ING4 differentially affects NF-KB-mediated gene induction in human glioma cells, inhibiting IL-8 expression, yet enhancing expression of matrix metalloproteinase-9 (MMP-9). These results suggest that the influence of ING4 on NF-KB-mediated genes is complex, i.e., ING4 may have either a positive or negative effect on gene expression that is dependent on promoter context, co- factor composition, chromatin accessibility, and kinetics of gene expression. We believe that studies to investigate the molecular mechanisms of ING4-mediated regulation of NF-KB activity in gliomas are warranted, focusing on ING4 regulation of expression of IL-8, IL-6, MMP-9 and CXCR4, all genes dependent on NF-KB for activation, and involved in glioma growth, invasion and angiogenesis. We will examine the status and integrity of the ING4 gene and the activation status of NF-KB in human glioma tissues, and determine if correlates exist. The effect of ING4 on NF-KB's ability to translocate into the nucleus, bind DNA in vitro and in vivo, and regulate expression of IL-8, IL-6, MMP-9 and CXCR4 will be analyzed in human glioma cells that inducibly express ING4 (Aim 1). In Aim 2, translational studies will validate the influence of ING4 on NF-KB-mediated gene expression in vivo. Human glioma cells inducibly expressing ING4 will be transplanted into the brains of scid mice, and the effects of changes in ING4 expression on NF-KB activity, gene expression, glioma growth, invasion and angiogenesis assessed in vivo. This combination of basic science experimentation and translational studies represent the first systematic study of the functional involvement of NF-KB and ING4 in gliomagenesis, and will lead to a greater understanding of the potential for therapeutic intervention of the NF-KB pathway and/or ING4 in malignant gliomas.