New Molecular Approaches to Inhibit Glioma Angiogenesis

描述：（申请人的摘要）胶质母细胞瘤（GBM）是最常见的恶性肿瘤之一。 化疗耐药和血管生成类型的肿瘤。几种治疗方法 未能改变超过12个月的诊断存活率。其广泛目标 这项提议的一个重要方面是研究抑制血管生成的新方法 在GBM中使用不同的动物模型。缺氧诱导因子1 α 在缺氧条件下上调，并通过 血管内皮生长因子（VEGF）表达。正常野生型p53 促进MDM 2介导的HIF-la的泛素化和蛋白体降解 蛋白，从而限制VEGF诱导的血管生成。野生型p53功能丧失 与裸鼠异种移植物的新血管形成和生长有关 小鼠我们假设MDM 2的过度表达（在超过50%的人中观察到）， GBM），一个直接受p53调控的基因，也与对 在人GBM细胞系中的化疗，可能导致p53在细胞中的隔离。 p53-MDM 2复合物阻止正常的p53 MDM 2介导的 HIF-1a。在这里，我们显示flavopiridol，一种新的蛋白激酶抑制剂， 报告的抗血管生成活性，下调胶质瘤中HIF-1a的表达 细胞系，从而提供了一种机制，其抗血管生成 活动拟议的研究将评估MDM 2反义治疗， 无flavopiridol促进胶质瘤中MDM 2表达下调 细胞系和异种移植物，上调p53介导的反应和下调 调节HIF-1a/VEGF表达以减少血管生成信号。这 将通过1）使用体外研究来优化MDM 2反义寡核苷酸， 以及促进p53功能和/或降低p53活性的药物治疗条件 HIF-1 α/VEGF表达。2)使用 的小鼠胶质瘤GL 261颅内血管生成模型，以确定 Flavopiridol降低HIF-1a/VEGF表达和抗血管生成的能力 在缺氧条件下的活动。3，4）使用裸鼠异种移植物， 以测定MDM 2的体内活性 用或不用夫拉吡啶醇进行反义处理以抑制血管生成， 肿瘤在缺氧条件下生长。

DESCRIPTION: (Applicant's Abstract) Glioblastoma (GBM) is one of the most chemoresistant and angiogenic types of tumors known. Several treatments have failed in altering survivals beyond 12 months of diagnosis. The broad objective of this proposal will be to investigate new approaches to inhibit angiogenesis in GBM using different animal models. Hypoxia-inducible factor l alpha (HIF-1a) becomes up regulated in hypoxic conditions and leads to angiogenesis via vascular endothelial growth factor (VEGF) expression. Normally wildtype p53 promotes MDM2-mediated ubiquitination and proteosomal degradation of the HIF-la protein, thus limiting VEGF-induced angiogenesis. Loss of wildtype p53 function has been associated with neovascularization and growth of xenografts in nude mice. We hypothesize that overexpression of MDM2 (seen in more than 50 percent of GBM), a gene directly regulated by p53 and also linked with resistance to chemotherapy in human GBM cell lines, could lead to the sequestration of p53 in p53-MDM2 complexes preventing the normal p53 MDM2-mediated degradation of HIF-1a. Here we show flavopiridol, a novel protein kinase inhibitor with reported antiangiogenic activity, down regulates HIF-1a expression in glioma cell lines in vitro, thus providing one mechanism for its antiangiogenic activity. The proposed studies will evaluate MDM2 antisense treatment with and without flavopiridol to promote down regulation of MDM2 expression in glioma cell lines and xenografts, up regulation of p53-mediated responses and down regulation of HIF-1a/VEGF expression to decrease angiogenic-signaling. This will be accomplished by 1) Use of in vitro studies to optimize MDM2 antisense and drug treatment conditions that promote p53 function and/or decrease HIF-la/VEGF expression, respectively, under hypoxic growth conditions. 2) Use of the murine glioma GL261 intracranial model of angiogenesis to determine the capacity of flavopiridol to decrease HIF-1a/VEGF expression and antiangiogenic activity in hypoxic conditions. 3,4) Use of nude mice xenografts both subcutaneously and intracranially to determine the in vivo activity of MDM2 antisense treatment with and without flavopiridol to inhibit angiogenesis and tumor growth in hypoxic conditions.