The role of Nrf2 in the tumour microenvironment of IDH wild-type glioma

高级别IDH野生型神经胶质瘤是复杂和破坏性的脑肿瘤，尽管有多种治疗模式，包括手术，化疗和放疗，但生存时间仍然很短，平均约为14个月。大胶质细胞和小胶质细胞是已被证明与胶质瘤肿瘤相关并积极促进胶质瘤生长的免疫细胞类型。然而，它们如何实现其促肿瘤活性尚不清楚。核因子红细胞2相关因子2（Nrf2）是一种蛋白质，被称为细胞氧化还原稳态的主调节剂。Nrf2被衣康酸激活，衣康酸是一种当巨噬细胞受到各种病原体刺激或巨噬细胞与肿瘤细胞接触时在线粒体中产生的化合物。活化的Nrf2然后抑制促进炎症的过多因子（称为细胞因子和趋化因子）的产生，因此Nrf2活化在炎症的解决和预防慢性炎症中起着至关重要的作用，否则可能导致细胞死亡和组织损伤。在这里，我们提出与胶质瘤细胞的关联增加了巨噬细胞和小胶质细胞中衣康酸的水平，这反过来又激活了Nrf2，创造了一个有利于肿瘤生长的抗炎环境。我们旨在回答以下研究问题：1.在与胶质瘤细胞结合后，激活脑巨噬细胞和小胶质细胞中的Nrf2的分子机制是什么？Nrf2如何影响胶质瘤细胞与脑巨噬细胞和小胶质细胞之间的相互作用？2.在斑马鱼模型中，与神经胶质瘤细胞的关联是否激活了巨噬细胞和小胶质细胞中的Nrf2？怎么做？在肿瘤发展的哪个阶段会发生这种情况？为了实现这些目标，我们将使用具有不同水平的Nrf2活性的巨噬细胞和小胶质细胞。我们将这些免疫细胞暴露于神经胶质瘤细胞的培养基中，或与神经胶质瘤细胞一起生长，并定量测定促炎因子和抗炎因子的表达。然后，我们将评估具有不同Nrf2水平的巨噬细胞和小胶质细胞对胶质瘤细胞生长、迁移和侵袭的影响。使用斑马鱼神经胶质瘤模型，结合实时成像，我们将分析神经胶质瘤的发展，并确定Nrf2（激活或抑制）对巨噬细胞和肿瘤细胞之间的相互作用以及对肿瘤细胞生长的影响。这些知识将为抑制巨噬细胞和小胶质细胞的促肿瘤活性，并设计有效的抗癌治疗方法提供可能性。如果如假设的那样，Nrf2在巨噬细胞和小胶质细胞中的活化是促进胶质瘤发展的原因，那么抑制Nrf2活性的化合物的可用性提供了一个令人兴奋的机会来测试它们在临床前模型中以及最终在临床试验中对胶质瘤发展的作用。

High-grade IDH wild-type gliomas are complex and devastating brain tumours, for which in spite of multiple modes of treatment, including surgery, chemotherapy and radiation therapy, survival times remain very short, on average of ~14 months. Macrophages and microglia are types of immune cells that have been shown to associate with glioma tumours and actively promote glioma growth. However, how they achieve their tumour-promoting activity is not clear. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a protein that is known as the master regulator of the cellular redox homeostasis. Nrf2 is activated by itaconate, a compound produced in mitochondria when macrophages are stimulated by various pathogens, or when macrophages come in contact with tumours cells. The activated Nrf2 then suppresses production of a plethora of factors (known as cytokines and chemokines) that promote inflammation, and thus Nrf2 activation plays a crucial role in the resolution of inflammation and in preventing chronic inflammation, which could otherwise lead to cell death and tissue damage. Here, we propose that association with glioma cells increases the levels of itaconate in macrophages and microglia, which in turn activates Nrf2, creating an anti-inflammatory environment that favours tumour growth.We aim to answer the following research questions:1. What are the molecular mechanisms that, upon association with glioma cells activate Nrf2 in brain macrophages and microglia? How does Nrf2 affect the interactions between glioma cells and brain macrophages and microglia?2. Does association with glioma cells activate Nrf2 in macrophages and microglia in a zebrafish model? How? At which stages during tumour development does this occur?To achieve these aims, we will use macrophage and microglia cells with different levels of Nrf2 activity. We will expose these immune cells to media from glioma cells, or grow them together with glioma cells, and quantitatively determine the expression of pro- and anti-inflammatory factors. We will then assess the effect of macrophage and microglia cells with different levels of Nrf2 on glioma cell growth, migration and invasion. Using zebrafish glioma models, combined with live imaging, we will analyse glioma development and determine the effect of Nrf2 (activation or suppression) on the interactions between macrophages and tumour cells, and on the growth of the tumour cells. This knowledge will open possibilities to suppress the pro-tumoural activity of macrophages and microglia, and design effective anti-cancer treatments. If as hypothesized, Nrf2 activation in macrophage and microglia cells is responsible for promoting glioma development, the availability of compounds that inhibit the activity of Nrf2, provides an exciting opportunity to test their effect on glioma development in preclinical models and ultimately, in clinical trials.