Mechanism and therapeutic potential of microglia regulation in glioblastoma

项目摘要 胶质母细胞瘤(GBM)是成年人中最致命的脑癌形式。GBM患者的中位生存期为 仅在首次诊断后约14-16个月。基因组图谱将GBM分成不同的亚群， 这是由核心信号通路的特定遗传变化驱动的。然而，靶向治疗，如 作为针对受体酪氨酸激酶信号转导的治疗，在临床上都失败了。肿瘤细胞遗传异质性 是这次失败的主要原因之一。相反，基底膜的肿瘤微环境(TME)是遗传的 稳定，被认为是有希望的治疗靶点。肿瘤相关的小胶质细胞和巨噬细胞 (TAMs)是TME中最丰富的细胞群，占GBM细胞总数的50% 肿瘤肿块。我们最近的研究表明，昼夜节律调节基因Clock/BMAL1是一种致癌基因。 GBM和胶质瘤干细胞(GSCs)高表达，GSCs通过促进GSC自我更新 代谢效应，并通过上调趋化因子类分子3(OLFML3)将小胶质细胞招募到TME中 表达(Chen等人，癌症发现，2020年)。然而，OLFML3的潜在分子基础是 触发小胶质细胞的渗透，进而影响免疫抑制和免疫治疗 尚未确定。因此，我们在这项研究中的总体目标是解决这种知识差距，并在这样做的过程中 将开发针对小胶质细胞的潜在治疗策略来治疗GBM。为了实现这些目标，我们 提出三个具体目标。在目标1中，我们将在小胶质细胞中鉴定OLFML3传感器/受体或结合蛋白， 并确定其在介导OLFML3诱导的Clock/BMAL1高GBM小胶质细胞浸润中的作用。在AIM 2，我们将确定OLFML1诱导的小胶质细胞的关键细胞内通路 迁移和GBM进展。在目标3中，我们将研究抑制小胶质细胞渗透是否可以 逆转GBM对免疫治疗的原发耐药性，从而开发新的治疗策略 免疫检查点抑制剂抑制小胶质细胞的渗透。我们建议采用综合战略 结合功能获得和功能丧失的方法，体外和体内系统，以及蛋白质组和 转录分析，以测试每个目标。总之，这个项目将揭示小胶质细胞的新机制 并揭示了GBM免疫治疗的新策略。

Project Summary Glioblastoma (GBM) is the most lethal form of brain cancer in adults. The median survival of GBM patients is only about 14-16 months after initial diagnosis. Genomic profiling has stratified GBM into various subgroups, which are driven by specific genetic alternations of core signaling pathways. However, targeted therapies, such as therapies against receptor tyrosine kinase signaling, have failed in the clinic. Tumor-cell genetic heterogeneity is one of the main reasons for this failure. In contrast, the tumor microenvironment (TME) of GBM is genetically stable, and are considering as the promising therapeutic targets. Tumor-associated microglia and macrophages (TAMs) are the most abundant cell population in the TME, which account for up to 50% of total cells in the GBM tumor mass. Our recent studies have demonstrated that circadian regulator CLOCK/BMAL1 is an oncogene in GBM and highly expressed in glioma stem cells (GSCs), which acts to increase GSC self-renewal through metabolic effects, and recruit microglia into the TME by upregulating chemokine olfactomedin-like 3 (OLFML3) expression (Chen et al., Cancer Discovery, 2020). However, the underlying molecular basis for how OLFML3 triggers microglial infiltration and subsequently how microglia affect immunosuppression and immunotherapy has yet to be determined. Thus, our overall goal in this study is to address this knowledge gap, and in so doing will develop potential therapeutic strategies targeting microglia for treating GBM. To achieve these goals, we propose three specific Aims. In Aim 1, we will identify OLFML3 sensor/receptor or binding protein in microglia, and determine its role in mediating OLFML3-induced microglial infiltration in CLOCK/BMAL1-high GBM. In Aim 2, we will determine the key microglial intracellular pathways that are responsible for OLFML1-induced microglial migration and GBM progression. In Aim 3, we will investigate whether inhibition of microglial infiltration can reverse primary resistance to immunotherapy in GBM, thus developing novel therapeutic strategies combining inhibition of microglia infiltration with immune checkpoint inhibitors. We propose to employ integrated strategies combining gain- and loss-of-function approaches, in vitro and in vivo systems, as well as proteomic and transcriptomic analysis to test each Aim. Together, this project will uncover novel mechanisms for microglial infiltration and reveal new immunotherapeutic strategies for GBM.