Centrosome Over-duplication and Blood Vessel Function

描述（由申请人提供）：肿瘤血管具有影响肿瘤发病机制的形态发生缺陷，主要通过启动缺氧相关信号传导。肿瘤中的血管迂曲、扩张、渗漏。有限的证据表明，肿瘤内皮细胞（ECs）有多余的中心体，这可能解释其异常表型。然而，负责这些细胞变化的机制在很大程度上是不确定的。我们的研究小组最近证实，过量的VEGF信号增加了发育中的血管和人类EC中中心体过度复制的频率。不相等的中心体数目（>2）会破坏细胞的微管组织中心，从而产生有害的细胞后果。在血管生成发芽过程中，“缺陷”EC的繁殖和同化可以部分解释肿瘤组织中常见的曲折、渗漏和/或化学抗性血管表型。该提议旨在检验肿瘤血管EC在中心体数量失调下游异常的假设，并且这种失调有助于肿瘤血管的异常结构和功能。因此，我们将在两个目标中检验这一假设。目的#1将确定中心体失调对EC行为的机制和后果。将遗传扰动引入人原代EC中以引起中心体过度复制，而不依赖于多效性促血管生成信号传导。将在迁移测定和3D-血管生成测定中挑战修饰的EC，其中它们将在体外增殖、发芽和分支，以确定中心体失调对血管生成的影响。目标#2将确定肿瘤进展与肿瘤血管EC中中心体复制之间的联系。使用一种新的转基因方法来标记EC DNA，我将分析中心体异常与肿瘤分期和侵袭性相关的小鼠乳腺肿瘤的内皮隔室，以确定中心体复制失调对肿瘤进展的影响。此外，将离体分离和培养肿瘤和正常EC，并在目标1中进行相同的功能测定。这项研究的信息将阐明肿瘤血管生成中的关键早期事件（中心体复制失调），并显示这些事件如何与异常血管发育和肿瘤进展联系起来。

DESCRIPTION (provided by applicant): Tumor blood vessels have morphogenetic defects that impact tumor pathogenesis, primarily through the initiation of hypoxia-related signaling. Vessels found in tumors are tortuous, dilated and leaky. Limited evidence has indicated that tumor endothelial cells (ECs) have excess centrosomes, which may explain their abnormal phenotype. However, the mechanisms responsible for these cellular alterations are largely undefined. Our group recently demonstrated that excess VEGF signaling increases the frequency of centrosome over-duplication in developing blood vessels and in human ECs. Unequal centrosome numbers (>2) can have deleterious cellular consequences due to disruption of the cells microtubule-organizing center. Propagation and assimilation of "defective" ECs during angiogenic sprouting may explain, in part, the tortuous, leaky and/or chemoresistant blood vessel phenotype commonly observed in tumor tissue. This proposal aims to test the hypothesis that tumor vessel ECs are abnormal downstream of centrosome number dysregulation, and that this dysregulation contributes to the abnormal structure and function of tumor vessels. Accordingly, we will test this hypothesis in two aims. Aim #1 will determine the mechanisms and consequences of centrosome dysregulation on EC behaviors. Genetic perturbations will be introduced into human primary ECs to cause centrosome over-duplication, independent of pleiotropic proangiogenic signaling. Modified ECs will be challenged in a migratory assay and a 3D-angiogenesis assay in which they will proliferate, sprout and branch in vitro to determine the effects of centrosome dysregulation on angiogenesis. Aim #2 will determine the linkage between tumor progression and centrosome duplication in ECs of tumor vessels. Using a novel transgenic approach to mark EC DNA, I will analyze the endothelial compartment in mouse mammary tumors for centrosome abnormalities to be correlated with tumor stage and invasiveness to determine the effects of dysregulation of centrosome duplication on tumor progression. Additionally, tumor and normal ECs will be isolated and cultured ex vivo and challenged to the same functional assays in aim #1. Information from this investigation will illuminate key early events (dysregulation of centrosome duplication) in tumor blood vessel angiogenesis, and show how these events link to abnormal vessel development and tumor progression.