Overproduction of vascular endothelial growth factor related to von Hippel-Lindau tumor suppressor gene mutations and hypoxia-inducible factor-1α expression in renal cell carcinomas
Overproduction of vascular endothelial growth factor related to von Hippel-Lindau tumor suppressor gene mutations and hypoxia-inducible factor-1α expression in renal cell carcinomas
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DOI：
10.1097/01.ju.0000074870.54671.98
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发表时间：
2003-08-01
影响因子：
6.6
通讯作者：
Messing, EM
中科院分区：
文献类型：
--
作者：
Na, X;Wu, G;Messing, EM
目的：von Hippel-Lindau （VHL）肿瘤抑制基因在常见的散发性透明细胞肾细胞癌（RCC）以及与VHL疾病相关的RCC中经常失活。VHL蛋白靶向缺氧诱导因子-1 α (hif -1 α)，一种可以诱导血管内皮生长因子（VEGF）表达的转录因子，用于泛素化和降解。突变的VHL蛋白引起肿瘤细胞中hif -1 α的积累可能导致VEGF过表达，这被用来解释RCC的血管性增加。然而，缺乏对RCC患者真实组织中VEGF生成及其与VHL突变和hif -1 α表达相关性的定量分析。材料和方法：我们通过直接DNA测序和甲基化特异性聚合酶链反应分析了31对RCC组织样本的VHL基因突变。采用免疫印迹法和免疫组化染色检测hif -1 α蛋白的表达，采用酶联免疫吸附法和免疫组化染色检测VEGF蛋白的表达。结果：在44%的透明细胞rcc中检测到VHL基因突变，但在启动子或外显子1的甲基化模式上没有发现差异。VHL基因突变或晚期rcc的VEGF浓度显著升高（p < 0.0001）。在40%的透明细胞rcc中发现hif -1 α蛋白表达，但其中80%有VHL突变（p < 0.006）。hif -1 α表达与VEGF生成水平升高直接相关（p < 0.0001）。结论：我们的研究结果表明，VHL基因改变和HIF-1a蛋白表达与RCC中VEGF产生的显著增加相关。反过来，它与更具侵袭性的肿瘤表型相关。
Purpose: The von Hippel-Lindau (VHL) tumor suppressor gene is frequently inactivated in the common type of sporadic clear cell renal cell carcinoma (RCC) as well as RCCs associated with VHL disease. The VHL protein targets hypoxia-inducible factor-1alpha (HIF-1alpha), a transcription factor that can induce vascular endothelial growth factor (VEGF) expression, for ubiquitination and degradation. Accumulation of HIF-1alpha caused by mutant VHL protein in tumor cells may result in VEGF over expression, which has been used to explain the increased vascularity of RCC. However, quantitative analyses of VEGF production and its correlation with VHL mutations and HIF-1alpha expression in authentic tissues from patients with RCC are lacking.Materials and Methods: We analyzed VHL gene mutations by direct DNA sequencing and methylation specific polymerase chain reaction in 31 paired RCC tissue samples. HIF-1alpha protein expression detected by immunoblotting and immunohistochemical staining, and VEGF protein measured by enzyme-linked immunosorbent assay and immunohistochemical staining were performed using tumor and corresponding normal tissues.Results: VHL gene mutations were detected in 44% of clear cell RCCs but no differences in methylation patterns in the promoter or exon 1 were found. RCCs with VHL gene mutations or of advanced grade produced significantly higher concentrations of VEGF (p < 0.0001). HIF-1alpha protein expression was found in 40% of clear cell RCCs but 80% of them had VHL mutations (p < 0.006). HIF-1alpha expression correlated directly with higher levels of VEGF production (p < 0.0001).Conclusions: Our findings indicate that VHL gene alterations and HIF-1a protein expression correlate with a significant increase in VEGF production by RCC. In turn it is associated with a more aggressive tumor phenotype.