Regulation of a DNA damage response network in glioblastoma

描述（由申请人提供）：\最近对癌症基因组的分析表明，DNA损伤抗性等复杂表型可能是由生物网络的扰动引起的。多形性胶质母细胞瘤（GBM）是最常见和致命的原发性成人脑癌。不幸的是，大多数GBM对放射（RT）和化疗（chemo）表现出极强的耐药性。因此，预后仍然是所有肿瘤中最低的，中位生存期约为一年。尽管如此，5-10%的GBM患者是相对长期的幸存者，中位生存期为3-4年。通过全基因组分析，我们发现这些患者缺乏与RT/化疗耐药相关的生物网络。该网络主要由干扰素刺激基因（ISGs）组成，并作为DNA损伤反应（DDR）的一部分被诱导。我们专注于描述网络中关键基因的功能，这些基因与患者生存密切相关，被预测调节网络，和/或在GBM肿瘤中长期幸存者中遗传或表观遗传失活。我们特别关注DNA损伤后参与网络的信号通路。特异性目标1探讨了干扰素相关信号通路如何激活该网络。为此，我们结合了无偏倚的全基因组方法和体外功能分析。特异性目标2研究网络基因ISG15（一种泛素样分子）如何作用于网络上的负反馈以限制DDR。我们描述了ISG15如何影响染色质环境以影响信号事件，并研究了这对DDR的重要性。在Specific Aim 3中，使用GBM小鼠模型检查了这些途径的生物学相关性。在这里，我们研究了网络对GBM肿瘤体内生长和RT反应的影响。通过这些目标，我们将获得重要的见解，了解DDR如何与抗病毒反应交叉，以及isg网络的失活如何有助于延长GBM患者的生存期。

DESCRIPTION (provided by applicant): \Recent analysis of cancer genomes suggests that complex phenotypes such as DNA damage resistance may result from perturbations of a biological network. Glioblastoma multiforme (GBM) is the most common and deadly primary adult brain cancer. Unfortunately, the majority of GBM show extreme resistance to radiation (RT) and chemotherapy (chemo). Accordingly, prognosis remains among the lowest of all tumors with a median survival of about one year. Despite this, 5-10% of GBM patients are relative long-term survivors with a median survival of 3-4 years. Through genome-wide analysis, we have discovered that these patients lack a biological network associated with RT/chemo resistance. This network is largely comprised of interferon- stimulated genes (ISGs) and is induced as part of the DNA damage response (DDR). We focus on characterizing the function of key genes in the network that strongly associate with patient survival, are predicted to regulate the network, and/or are genetically or epigenetically inactivated in GBM tumors from long- term survivors. In particular, we focus on signaling pathways that engage the network after DNA damage. Specific Aim 1 explores how the network is activated by interferon-related signaling pathways. For this, we combine unbiased genome-wide approaches and in vitro functional assays. Specific Aim 2 investigates how the network gene ISG15, an ubiquitin-like molecule, acts to negatively feedback on the network to limit the DDR. We characterize how ISG15 influences the chromatin environment to affect signaling events and investigate the importance of this on the DDR. In Specific Aim 3, the biological relevance of the pathways is examined using a GBM mouse model. Here, we investigate the impact of the network on growth and RT response of GBM tumors in vivo. Through these aims, we will gain important insight into how the DDR intersects with the anti-viral response, and how the inactivation of a network of ISGs might contribute to prolonged survival of a subset of GBM patients.