The Role of CD147 in Glioblastoma Invasiveness

胶质母细胞瘤是中枢神经系统的一种原发癌症。不幸的是，目前的治疗方法是 无法控制肿瘤的侵袭性，导致95%的复发率。此外，尽管辐射 治疗对这些患者的生存率产生了最大的改善，它还与 肿瘤侵袭性增加，可能是导致复发率高的原因之一。我们的初步工作表明 CD147，一种在胶质母细胞瘤中普遍过度表达的蛋白质，可能与这种侵袭有关，在 特别是辐射暴露后侵袭性的增加。有趣的是，CD147促进了人类的侵袭 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 产生基质金属蛋白酶(MMPs)，降解细胞外基质。在胶质母细胞瘤中，我们有 发现胶质母细胞瘤细胞外小泡不仅含有CD147，而且它们的CD147水平 如果细胞受到辐射，则会更高。同样，我们发现胶质母细胞瘤细胞释放细胞外小泡， 增加星形胶质细胞中基质金属蛋白酶的产生，如果细胞外基质的产生进一步增加 小泡来自受辐射的胶质母细胞瘤细胞。综上所述，这些研究表明CD147可能起着关键作用 在胶质母细胞瘤肿瘤的侵袭性和放射后侵袭性增加中的作用。 因此，这项研究提出了两个具体的目标来检验胶质母细胞瘤细胞使用的中心假设 含有CD147的胞外小泡可调节支持侵袭的环境。我们进一步假设 辐射增加了细胞外小泡中CD147的水平，导致侵袭性增加。 在目标1中，我们将在体外检测胶质母细胞瘤细胞胞外小泡中的CD147是否可以 诱导星形胶质细胞和小胶质细胞通过产生基质金属蛋白酶促进侵袭，以及辐射是否增强 这一过程。通过敲除CD147，我们将研究CD147是如何通过 分析基质金属蛋白酶蛋白和信使核糖核酸水平、分泌基质金属蛋白酶的数量和活性以及信号转导途径。 导致基质金属蛋白酶产生的途径。我们还将使用以下工具测试CD147对功能端点的影响 侵袭和迁移分析。在目标2中，我们将在体内证明CD147是一种重要的 肿瘤侵袭性，尤其是在辐射暴露后。我们将使用一种原位小鼠脑胶质瘤模型 由野生型和CD147基因敲除的肿瘤细胞组成。使用最先进的系统模拟临床 治疗时，我们将在CT图像引导下对肿瘤进行特定的X射线照射。我们将研究差异 在生存方面，脑内转移的数量，以及免疫组织学终点。预计辐射将 CD147野生型肿瘤与未照射对照相比，侵袭性增加。然而，我们预测， 辐射和CD147基因敲除的结合将协同作用，产生最低水平的 团体之间的入侵。这些结果可能表明CD147抑制剂是辐射的重要佐剂。 治疗，有助于减少侵袭性，从而提高患者的存活率。

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.