Department of Ophthalmology, Leiden University Medical Center, Leiden, The Netherlands.
Invest Ophthalmol Vis Sci. 2010 May;51(5):2329-37. doi: 10.1167/iovs.09-4739. Epub 2009 Dec 30.
Blood vessels are important constituents of intraocular uveal melanoma (UM), but whether angiogenesis is regulated by environmental factors such as ischemia or by genetic mechanisms is not known. This study was undertaken to examine the regulation of the proangiogenic factor vascular endothelial growth factor (VEGF-A).
Cell lines and primary tumors were tested for expression of VEGF-A, under normoxic and hypoxic conditions, using quantitative PCR, ELISA, WST-1 viability, and in-cell Western experiments. VEGF-A serum levels were determined by ELISA.
Hypoxia induced expression of HIF-1alpha and VEGF-A in UM cell lines and primary tumor cultures, but it did not influence proliferation. VEGF-A expression in primary tumors was variable, demonstrating no correlation with specific histologic markers or prognosis. However, VEGF-A levels were significantly raised in UM patients with metastases compared with those without metastases (P < 0.001).
VEGF-A expression by UM cells is mainly controlled by hypoxia and involves the HIF-1alpha pathway, thus indicating an important role for the tumor cell environment. Metastases led to increased serum VEGF-A levels, indicating that VEGF-A may be involved in the growth of metastases.
血管是眼内葡萄膜黑色素瘤（UM）的重要组成部分，但血管生成是受环境因素（如缺血）还是遗传机制调节尚不清楚。本研究旨在研究促血管生成因子血管内皮生长因子（VEGF-A）的调节。
使用定量 PCR、ELISA、WST-1 活力和细胞内 Western 实验，在常氧和低氧条件下检测细胞系和原代肿瘤中 VEGF-A 的表达。通过 ELISA 测定 VEGF-A 血清水平。
低氧诱导 UM 细胞系和原代肿瘤培养物中 HIF-1alpha 和 VEGF-A 的表达，但不影响增殖。原代肿瘤中的 VEGF-A 表达具有可变性，与特定的组织学标志物或预后无相关性。然而，与无转移的患者相比，有转移的 UM 患者的 VEGF-A 水平显著升高（P<0.001）。
UM 细胞的 VEGF-A 表达主要受低氧调控，并涉及 HIF-1alpha 途径，因此表明肿瘤细胞环境的重要作用。转移导致血清 VEGF-A 水平升高，表明 VEGF-A 可能参与转移的生长。
