Hypoxia VHL nad HIF in Renal Tumor Development

缺氧 VHL 和 HIF 在肾肿瘤发展中的作用

• 批准号: 7046046
• 负责人: Volker Hans Haase
• 金额: $ 25.38万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-01 至 2009-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7046046
• 关键词: RNase protection assay; apoptosis; cell growth regulation; embryonic stem cell; gene expression; gene induction /repression; gene mutation; gene targeting; genetically modified animals; hypoxia; hypoxia inducible factor 1; in situ hybridization; laboratory mouse; microarray technology; neoplastic transformation; northern blottings; nucleic acid probes; protein isoforms; protein structure function; renal cell carcinoma; tissue /cell culture; tumor suppressor genes; urinary bladder epithelium; western blottings

DESCRIPTION (provided by applicant): Clear cell carcinoma of the kidney (RCC), the most common form of kidney cancer, is associated with the inactivation of the von HippeI-Lindau (VHL) tumor suppressor. Mutations in the VHL gene can be found in approximately 70% of sporadic RCCs. One of the major functions of the VHL gene product, pVHL, is the targeting of the oxygen sensitive alpha-subunit of hypoxia-inducible factor (HIF) for ubiquitination and subsequent proteasomal degradation. Inactivation of VHL is felt to be an early event during RCC tumorigenesis and results in constitutive expression of two major HIF isoforms, HIF-1 and HIF-2. This results in increased transcription of genes that regulate glycolysis, angiogenesis and erythropoiesis. HIF-1 has furthermore been shown to up-regulate factors that promote growth arrest and apoptosis. The role of increased HIF expression in VHL associated tumorigenesis remains controversial. The hypothesis that the ratio of HIF-1 to HIF-2 levels is important for VHL associated renal tumor development will be investigated. Conditional gene targeting technology based on Cre-loxP mediated recombination as well as targeted transgenesis will be used to manipulate the expression levels of both pVHL and HIF in vivo and in vitro. This system enables the study of the functional relationship between VHL deficiency and HIF activation in regard to renal cell growth and viability in primary renal epithelial cells of different histogenetic origin. Specifically, the proposed investigations will examine the effects of increased or absent HIF-1 and increased HIF-2 expression in VHL deficient and wild type backgrounds. Studies will be performed in primary cell culture and in vivo with kidney specific conditional knock out mice. Gene expression studies will provide information regarding differential HIF-1 and HIF-2 target gene expression in different nephron segments with a special emphasis on genes involved in the regulation of cell survival. Taken all together, the proposed in vivo and in vitro studies will not only provide novel insights into the early events of renal oncogenesis and the histogenetic origin of RCC, but also examine fundamental aspects of HIF-1 and HIF-2 function in different nephron segments. Ultimately they have the potential to create a murine model of VHL associated renal tumors.

描述（由申请人提供）：肾透明细胞癌（RCC）是最常见的肾癌形式，与von HippeI-Lindau（VHL）肿瘤抑制因子的失活有关。VHL基因突变可在大约70%的散发性RCC中发现。VHL基因产物pVHL的主要功能之一是靶向低氧诱导因子（HIF）的氧敏感α亚基，用于泛素化和随后的蛋白酶体降解。VHL的失活被认为是RCC肿瘤发生过程中的早期事件，并导致两种主要HIF亚型HIF-1和HIF-2的组成型表达。这导致调节糖酵解、血管生成和红细胞生成的基因的转录增加。此外，HIF-1还显示上调促进生长停滞和凋亡的因子。HIF表达增加在VHL相关肿瘤发生中的作用仍有争议。将研究HIF-1与HIF-2水平的比率对于VHL相关的肾肿瘤发展是重要的这一假设。基于Cre-loxP介导的重组以及靶向转基因的条件基因靶向技术将用于操纵体内和体外pVHL和HIF的表达水平。该系统能够研究VHL缺陷和HIF激活在不同组织发生起源的原代肾上皮细胞中的肾细胞生长和活力方面之间的功能关系。具体而言，拟议的调查将检查VHL缺陷和野生型背景中HIF-1表达增加或缺失以及HIF-2表达增加的影响。研究将在原代细胞培养物中进行，并使用肾特异性条件性敲除小鼠进行体内研究。基因表达研究将提供有关差异HIF-1和HIF-2的靶基因表达在不同的肾单位节段，特别强调参与细胞存活的调节基因的信息。总之，在体内和体外的研究，不仅提供了新的见解肾肿瘤发生的早期事件和RCC的组织起源，但也检查HIF-1和HIF-2的功能在不同的肾单位段的基本方面。最终，他们有潜力创建VHL相关肾肿瘤的小鼠模型。