miRNA analysis of HBMVECs exposed or unexposed to U87 glioma cells

A key step in angiogenesis is the upregulation of growth factor receptors on endothelial cells. Here we demonstrate that a small regulatory microRNA, miR-296 has a major role in this process. Glioma cells and angiogenic growth factors elevate the level of miR-296 in primary human brain microvascular endothelial cells in culture. The miR-296 level is also elevated in primary tumor endothelial cells isolated from human brain tumors compared to normal brain endothelial cells. Growth factor-induced miR-296 contributes significantly to angiogenesis by directly targeting the hepatocyte growth factor-regulated tyrosine kinase substrate (HGS) mRNA, leading to decreased levels of HGS and thereby reducing HGS-mediated degradation of the growth factor receptors VEGFR2 and PDGFR-β. Furthermore, inhibition of miR-296 with antagomirs reduces angiogenesis in tumor xenografts in vivo. Keywords: comparitive miRNA analysis 3 biological replicates (HBMVECs) are compared to 3 biological replicates (HBMVECs exposed to U87 glioma cells)

血管生成（angiogenesis）的关键步骤之一是内皮细胞表面生长因子受体的表达上调。本研究证实，小型调控型微RNA（microRNA, miRNA）miR-296在该过程中发挥核心作用。胶质瘤细胞与促血管生成生长因子可在体外培养的原代人脑微血管内皮细胞（primary human brain microvascular endothelial cells, HBMVECs）中上调miR-296的表达水平。与正常脑内皮细胞相比，从人脑肿瘤中分离得到的原代肿瘤内皮细胞内的miR-296水平同样显著升高。生长因子诱导的miR-296可通过直接靶向肝细胞生长因子调控的酪氨酸激酶底物（hepatocyte growth factor-regulated tyrosine kinase substrate, HGS）的信使RNA（messenger RNA, mRNA），显著促进血管生成：该过程会降低HGS的蛋白表达水平，进而削弱HGS介导的血管内皮生长因子受体2（VEGFR2）与血小板衍生生长因子受体β（PDGFR-β）的降解。此外，使用antagomirs（miRNA拮抗寡核苷酸）抑制miR-296的功能，可在体内减少异种移植肿瘤中的血管生成。
关键词：比较性miRNA分析；将3份生物学重复的原代人脑微血管内皮细胞（HBMVECs）与3份经U87胶质瘤细胞处理的原代人脑微血管内皮细胞进行对比分析。