Matrix stiffness mediated biglycan expression in the tumor vasculature

项目总结 血管生成指的是新血管从原有血管长出的过程。过份 血管生成是许多癌症的标志，并有助于癌症的进展。在肿瘤期间 生长时，血管生成开关被解除调节，导致异常的血管系统，其特征是 高渗透、曲折和未成熟的血管。不规则肿瘤的后果 血管系统包括肿瘤血流灌注不良导致缺氧和治疗药物受阻 送货。虽然众所周知，化学信号在调节肿瘤方面有很大的作用 血管生成，机械信号的影响正变得越来越明显。值得注意的是，细胞外 在许多癌症中，基质明显比正常组织僵硬，而且基质硬度升高 证明能促进血管生成并破坏屏障的完整性。我们实验室先前的工作表明，在 在体外和体内，增加基质交联度(导致更坚硬的基质)会增加内皮细胞 发芽并导致形成更多可渗透的血管。然而，管理 基质僵硬对内皮细胞功能的影响仍然知之甚少。揭开 驱动僵硬介导的内皮细胞效应的机制是开发新的 使肿瘤血管正常化和促进正常血管生长的方法。有趣的是，我们的 通过RNA测序获得的初步数据表明，内皮二聚糖的表达是 在体外和体内均受基质硬度的调节。此前，Biglycan已被确认为一种肿瘤 内皮细胞标志物和Biglycan的过度表达与几种癌症的预后不良有关。 值得注意的是，作为一种自分泌剂，Biglycan可以促进血管生成。虽然已经确定了Biglycan 在疾病中上调，并有助于病理性内皮细胞信号和行为，我们的数据 表明ECM的刚性可能会驱动这些效应。鉴于这些发现，我们将使用定制的 生物材料、转基因小鼠和最先进的生化分析，以调查这一假设 基质僵硬增加细胞收缩能力以驱动内皮细胞Biglycan表达升高和 促进异常血管生成和高通透性。在目标1中，支配的分子机制 将确定基质刚性驱动的内皮细胞Biglycan的表达。在目标2中，基质的作用 刚性介导的内皮二聚糖表达促进血管生成增加 将对高渗透表型进行研究。这项工作将提供关键的洞察力，让我们了解 肿瘤的机械特性调节血管系统的结构和完整性，并揭示 血管正常化的潜在治疗靶点，重点是内皮二聚糖 监管。

PROJECT SUMMARY Angiogenesis refers to the process by which new blood vessels grow from pre-existing ones. Excessive angiogenesis is a hallmark of many cancers and contributes to cancer progression. During tumor growth, the angiogenic switch is deregulated resulting in an abnormal vasculature characterized by hyperpermeable, tortuous, and immature blood vessels. Consequences of the irregular tumor vasculature include poor tumor perfusion resulting in hypoxia and hindrance to therapeutic drug delivery. While it is well established that chemical cues are heavily involved in regulating tumor angiogenesis, the influence of mechanical cues are becoming more apparent. Notably, the extracellular matrix is significantly stiffer than normal tissue in many cancers, and elevated matrix stiffness has been shown to promote angiogenesis and disrupt barrier integrity. Prior work in our lab has shown both in vitro and in vivo that increased matrix crosslinking (resulting in a stiffer matrix) increases endothelial sprouting and causes more permeable blood vessels to form. However, the mechanisms governing the effects of matrix stiffness on endothelial cell function are still poorly understood. Uncovering the mechanisms driving stiffness-mediated effects on endothelial cells is critical for developing novel approaches to normalize tumor vasculature and promote normal vessel growth. Interestingly, our preliminary data obtained through RNA-sequencing indicate that endothelial biglycan expression is regulated by matrix stiffness in vitro and in vivo. Previously, biglycan has been identified as a tumor endothelial cell marker and biglycan overexpression is correlated to poor prognosis in several cancers. Notably, biglycan can promote angiogenesis as an autocrine agent. While it is established that biglycan is upregulated in disease and contributes to pathological endothelial signaling and behavior, our data indicates that ECM stiffness may drive these effects. Given these findings, we will use tailored biomaterials, transgenic mice, and state of the art biochemical assays to investigate the hypothesis that matrix stiffness increases cellular contractility to drive elevated endothelial biglycan expression and promote aberrant angiogenesis and hyperpermeability. In aim 1, the molecular mechanism governing matrix stiffness driven endothelial biglycan expression will be determined. In aim 2, the effects of matrix stiffness-mediated endothelial biglycan expression in promoting increased angiogenesis and a hyperpermeable phenotype will be investigated. This work will provide critical insight into how the mechanical properties of tumors regulate the structure and integrity of vasculature and uncover potential therapeutic targets for vasculature normalization with a focus on endothelial biglycan regulation.