Role of Src family kinases in endothelial cell biology

描述（由申请方提供）：脑内皮屏障的特征在于具有低细胞旁通透性的特化内皮细胞。沿着基底膜和其他细胞类型，血脑屏障（BBB）是正常脑代谢的重要调节器。VEGF是由肿瘤分泌的生长因子，其可诱导血管通透性（VP）并破坏BBB的完整性。我们以前的研究已经证明了Src的要求，在宿主室VEGF诱导的血管通透性（VP），特别是在肺和脑。我们利用Src基因敲除小鼠的“渗漏抗性”表型来研究肿瘤生长和转移的特征。这些研究表明，Src的缺乏导致VEGF诱导的血管VP减少，从而提供对肺转移的保护。在脑中，VEGF诱导的VP减少也与Src介导的FAK磷酸化变化有关。最近的数据表明，FAK是丰富的脑血管相比，周围的细胞类型，是Src介导的VP的目标。我们假设FAK是维持BBB完整性的关键中间体。在目的1中，我们将描述Src在调节VEGF诱导的FAK活化和脑血管VP中的作用。这些研究将检查VP表型的分子基础，并将包括BMK 1和eNOS的表征。在目标2中，我们将确定Src是否在VEGF刺激的脑血管中调节BMK 1。在目的3中，我们将研究eNOS在Src与BMK 1介导的VEGF诱导的VP中的作用。虽然这些研究将为BBB的调节提供新的和重要的见解，但相对较少的研究已经检查了BBB在肿瘤转移中的作用。因此，我们将使用动物模型来确定FAK、BMK 1和eNOS在乳腺肿瘤向脑转移过程中在宿主隔室中的功能。这些研究将建立在我们以前的研究Src介导的转移到肺的Src在宿主隔室的作用，并提供了一个比较颅内肿瘤的生长和侵袭的特点。一组人星形细胞瘤可用于人胶质瘤生长和浸润的异种移植小鼠模型。这些研究的结果将在不同恶性程度的人脑肿瘤样本中进行验证，以确定VP和BBB在肿瘤生长和侵袭的各个阶段的临床病理学相关性。

DESCRIPTION (provided by applicant): The endothelial barrier of the brain is characterized by specialized endothelial cells with low paracellular permeability. Along with the basement membrane and other cell types, the blood brain barrier (BBB) is an important regulator of normal brain metabolism. VEGF is a growth factor secreted by tumors that can induce vascular permeability (VP) and disrupt the integrity of the BBB. Our previous studies have demonstrated a Src requirement in the host compartment for VEGF-induced vascular permeability (VP), particularly in the lung and brain. We have exploited the 'leakage-resistant1 phenotype of Src-knockout mice to examine the characteristics of tumor growth and metastasis. These studies have revealed that an absence of Src leads to reduced VEGF-induced VP of blood vessels providing protection from lung metastases. In the brain, a reduction in VEGF-induced VP has also been associated with Src-mediated changes in FAK phosphorylation. Recent data indicate that FAK is enriched in brain blood vessels compared to surrounding cell types, and is a target of Src-mediated VP. We hypothesize that FAK is a key intermediate in the maintenance of the integrity of the BBB. In Aim 1 we will characterize the role of Src in regulating VEGF- induced FAK activation and VP of brain blood vessels. These studies will examine the molecular basis for the VP phenotype and will include the characterization of BMK1 and eNOS. In Aim 2 we will determine whether Src regulates BMK1 in VEGF-stimulated brain blood vessels. In Aim 3 we will examine the role of eNOS in Src- vs. BMK1-mediated VEGF-induced VP. While these studies will provide novel and important insights into the regulation of the BBB, relatively few studies have examined the role of the BBB in tumor metastasis. Therefore, we will use animal models to determine the function of FAK, BMK1 and eNOS in the host compartment during breast tumor metastasis to the brain. These studies will build upon our previous studies of the role of Src in the host compartment in Src-mediated metastases to the lung and provide a comparison for the characterization of the growth and invasion of intracranial tumors. A panel of human astrocytomas is available for xenograft mouse models of human glioma growth and infiltration. The results of these studies will be validated in human brain tumor samples of varying malignancy to determine the clinicopathological relevance of VP and the BBB in various stages of tumor growth and invasion.