The Role of CD147 in Glioblastoma Invasiveness

胶质母细胞瘤是中枢神经系统的原发性癌症。不幸的是，目前的治疗方法 无法控制肿瘤的侵袭性，导致95%的复发率。虽然辐射 治疗对这些患者的生存率产生了最大的改善，它也与 肿瘤侵袭性增加，可能导致高复发率。我们的初步工作表明 CD147是一种在胶质母细胞瘤中通常过表达的蛋白质，可能有助于这种侵袭， 特别是辐射暴露后增加的侵袭。有趣的是，CD147可以促进细胞的侵袭， 癌细胞通过细胞间通讯：癌细胞分泌CD147诱导邻近的成纤维细胞， 产生降解细胞外基质的基质金属蛋白酶（MMP）。在胶质母细胞瘤中， 发现胶质母细胞瘤细胞的细胞外囊泡不仅含有CD 147，而且它们的CD 147水平也是 如果细胞受到辐射，同样，我们发现胶质母细胞瘤细胞释放细胞外囊泡， 增加星形胶质细胞中MMP产生，且如果细胞外 囊泡来自辐射的胶质母细胞瘤细胞。总之，这些研究表明，CD147可能发挥关键作用， 在胶质母细胞瘤肿瘤的侵袭性和照射后观察到的侵袭增加中起作用。 因此，本研究提出了两个具体的目标，以测试中心假设，胶质母细胞瘤细胞使用 含有CD147的细胞外囊泡介导促侵入环境。我们进一步假设， 辐射增加了细胞外囊泡中CD 147的水平，导致侵袭性增加。 在目标1中，我们将在体外研究胶质母细胞瘤细胞的细胞外囊泡中的CD147是否可以 诱导星形胶质细胞和小胶质细胞通过MMP产生促进侵袭，以及辐射是否增强 这个过程通过敲低CD147，我们将研究CD147如何通过以下途径控制入侵驱动因素： 分析MMP蛋白和mRNA水平，分泌的MMP的量和活性，以及信号传导， 导致MMP产生的途径。我们还将测试CD 147对功能终点的影响， 侵袭和迁移测定。在目标2中，我们将证明在体内，CD147是一个重要的调解人， 肿瘤侵袭性，特别是辐射暴露后。我们将使用原位胶质瘤小鼠模型 由野生型和CD147敲低的肿瘤细胞组成。使用最先进的系统模拟临床 治疗时，我们将对肿瘤进行特定的CT图像引导的X射线照射。我们将研究差异 存活率、脑内转移灶数量和免疫组织学终点。辐射预计将 相对于未照射的对照，增加了CD147野生型肿瘤的侵袭。然而，我们预测， 辐射和CD147敲低的组合将协同作用以产生最低水平的 群体之间的入侵。这些结果可能表明，CD147抑制剂作为一种重要的辅助辐射 治疗，有助于减少侵袭，从而提高患者的生存率。

Glioblastoma is a primary cancer of the central nervous system. Unfortunately, current treatments are unable to control the invasiveness of the tumor, leading to a 95% recurrence rate. Moreover, although radiation therapy has produced the largest improvement in survival for these patients, it is also associated with increased tumor invasiveness, perhaps contributing to the high recurrence rate. Our preliminary work suggests that CD147, a protein which is commonly overexpressed in glioblastoma, may contribute to this invasion, in particular the increased invasion after radiation exposure. Interestingly, CD147 works to promote invasion in cancer cells via intercellular communication: carcinomas secrete CD147 to induce neighboring fibroblasts to produce matrix metalloproteinases (MMPs), which degrade the extracellular matrix. In glioblastoma, we have found that extracellular vesicles from glioblastoma cells not only contain CD147, but their CD147 levels are higher if the cells are irradiated. Similarly, we found that glioblastoma cells release extracellular vesicles that increase MMP production in astrocytes, and that MMP production is further increased if the extracellular vesicles are from irradiated glioblastoma cells. Together, these studies suggest that CD147 may play a key role in both the invasiveness of glioblastoma tumors and the increased invasion observed following irradiation. Therefore, this study proposes two specific aims to test the central hypothesis that glioblastoma cells use extracellular vesicles containing CD147 to mediate a pro-invasive environment. We further hypothesize that radiation increases the levels of CD147 in extracellular vesicles, resulting in increased invasiveness. In Aim 1, we will examine in vitro whether CD147 in the extracellular vesicles of glioblastoma cells can induce astrocytes and microglia to promote invasion through MMP production, and whether radiation enhances this process. Through knockdown of CD147, we will examine how CD147 controls drivers of invasion by analyzing the MMP protein and mRNA levels, the amount and activity of secreted MMPs, and the signaling pathways leading to MMP production. We will also test the effects of CD147 on functional endpoints using invasion and migration assays. In Aim 2, we will demonstrate in vivo that CD147 is an important mediator of tumor invasiveness, in particular after radiation exposure. We will use an orthotopic mouse model of glioma consisting of wild-type and CD147-knockdown tumor cells. Using a state-of-the-art system that mimics clinical therapy, we will perform specific CT-image guided X-ray irradiation of the tumors. We will examine differences in survival, number of metastases in the brain, and immunohistological endpoints. Radiation is expected to increase invasion in the CD147 wild-type tumors, relative to non-irradiated controls. However, we predict that the combination of radiation and CD147 knockdown will act synergistically to generate the lowest level of invasion among the groups. These results may suggest CD147 inhibitors as an important adjuvant to radiation therapy, contributing to reduced invasion and thus improved patient survival.