The role and mechanism of necrosis in glioblastoma

项目摘要 胶质瘤是主要的原发性脑肿瘤，其中胶质母细胞瘤（GBM）是最常见和最具侵袭性的 forms.这些肿瘤的传统治疗效果不佳，需要基于以下方面的靶向治疗： 确定了驱动肿瘤发展的机制。分子病理学将GBM分为亚型， 其中间充质（MES）组是最恶性的。目前还不清楚GBM如何 实现了差异化。最近基于解剖学的转录组研究发现， 与坏死区有较高的MES标志基因表达，这表明坏死肿瘤 微环境可能有助于MES分化，并可用作治疗靶点。目标 本项目的主要目的是从机制和功能上研究GBM坏死，并识别GBM MES的脆弱性 治疗进展。我们为拟议的研究建立了以下前提。首先我们得 开发了新的病理学相关的GBM小鼠模型，显示MES分化和广泛坏死。 其次，我们确定了铁凋亡作为GBM坏死的一种新机制。第三，在两个患者GBM样品中， 在小鼠模型中，我们发现坏死的肿瘤区域被中性粒细胞浸润。我们的研究表明 这些肿瘤相关中性粒细胞（TAN）是诱导肿瘤细胞铁凋亡的必要和充分条件。 此外，我们发现铁凋亡和TAN与缺氧肿瘤微环境相关。我们 假设GBM坏死是通过嗜铁蛋白触发的铁凋亡发生的，并且这一过程是精心策划的， 缺氧的肿瘤微环境。我们进一步假设，铁下垂可以促进肿瘤 进展并被靶向用于治疗目的。我们提出以下三个具体目标： 探讨TANs诱导肿瘤细胞铁凋亡的机制; 2）探讨缺氧对肿瘤细胞铁凋亡的影响 肿瘤细胞铁凋亡的微环境; 3）证明铁凋亡在GBM进展中的作用， 评价铁下垂阻滞剂的治疗效果。我们将使用一组已建立的人GBM细胞系， 新分离的人GBM细胞和小鼠GBM模型。GBM坏死是一个诊断标志，预测 肿瘤侵袭性，并且对治疗具有有害影响。细胞死亡的本质和机制 与这种坏死相关的疾病仍不清楚。此外，肿瘤坏死阻断是否会受益于 治疗方法仍然未知。通过建立如实再现坏死范围的GBM模型， 在GBM患者中观察到，并将铁凋亡鉴定为肿瘤坏死的潜在机制， 该提案将揭示GBM MES进展的漏洞，这可能是GBM的新途径 治疗学

Project Summary Gliomas are major primary brain tumors, of which glioblastomas (GBM) are the most common and aggressive forms. The poor outcome of traditional treatment for these tumors demands targeted therapies based on identified mechanisms that drive tumor development. Molecular pathology has classified GBM into subtypes, among which the mesenchymal (MES) group is the most malignant. It is still unclear how GBM MES differentiation is achieved. Recent anatomically based transcriptome studies found that tumor cells associated with the necrotic region have higher expression of the MES signature genes, suggesting that the necrotic tumor microenvironment may contribute to MES differentiation and could be exploited as a therapeutic target. The goal of this project is to mechanistically and functionally study GBM necrosis, and identify vulnerabilities of GBM MES progression for therapeutics. We have established the follow premise for the proposed studies. First, we have developed novel pathologically relevant GBM mouse models showing MES differentiation and extensive necrosis. Second, we identified ferroptosis as a novel mechanism for GBM necrosis. Third, in both patient GBM samples and mouse models, we found that the necrotic tumor areas are infiltrated by neutrophils. Our studies suggested that these tumor-associated neutrophils (TANs) are necessary and sufficient to induce tumor cell ferroptosis. Furthermore, we found that ferroptosis and TANs are associated with the hypoxic tumor microenvironment. We hypothesize that GBM necrosis occurs through neutrophil-triggered ferroptosis, and this process is orchestrated by the hypoxic tumor microenvironment. We further hypothesize that ferroptosis could promote tumor progression and be targeted for therapeutic purposes. We propose the following three specific aims: 1) to determine the mechanism of tumor cell ferroptosis induced by TANs; 2) to determine the role of hypoxic tumor microenvironment in tumor cell ferroptosis; 3) to demonstrate the role of ferroptosis in GBM progression and evaluate therapeutic effects of ferroptosis blockade. We will employ a panel of established human GBM cell lines, newly isolated human GBM cells, and mouse GBM models. GBM necrosis is a diagnostic hallmark, predicts tumor aggressiveness, and has deleterious effects on treatments. The nature and mechanism of cell death associated with this necrosis remain obscure. In addition, whether tumor necrosis blockade could benefit therapies is still unknown. By establishing the GBM models faithfully recapitulating the extent of necrosis observed in GBM patients and identification of ferroptosis as the underlying mechanism of tumor necrosis, this proposal will reveal vulnerabilities of GBM MES progression, which could be a novel avenue for GBM therapeutics.