Mechanism and therapeutic potential of macrophage regulation in glioblastoma

项目摘要/摘要 胶质母细胞瘤(GBM)是成人最致命的脑癌，中位生存期为一年。 诊断。不幸的是，常规治疗和靶向治疗都未能提高GBM患者的存活率。 在过去的40年里。肿瘤微环境(TME)中的免疫细胞在遗传上是稳定的，并具有 成为很有希望的治疗靶点。肿瘤相关巨噬细胞/小胶质细胞(TAMs)是最多的 大量免疫细胞渗入GBM TME(可占活细胞总数的50%)，在那里它们 在促进肿瘤进展和诱导免疫治疗抵抗方面发挥重要作用。然而， 靶向治疗或免疫治疗的承诺在GBM尚未实现，部分原因是 对行为和功能的分子机制认识有限。 我在DePinho实验室的博士后工作揭示了管理巨噬细胞招募的新机制 和小胶质细胞进入GBM TME。值得注意的是，我确定靶向巨噬细胞/小胶质细胞通过 抑制赖氨酰氧化酶(LOX)或昼夜节律时钟是一种有希望的治疗方法 GBM(Chen等人，癌症细胞2019；Chen at等人，癌症发现，正在修订中)。在招募时， 巨噬细胞/小胶质细胞表现出一系列的表型，包括免疫刺激的M1表型和 免疫抑制的M2表型。众所周知，GBM中的TAM通常偏振于M2 表型，并将TAMS从M2表型重新编程为M1表型，可能是一种有前途的治疗策略 GBM。我的初步研究表明，TAMS在GBM中统一表达TANK结合蛋白1(TBK1 这种可药物的激酶可以控制巨噬细胞在M1和M2表型之间的极化切换。 巨噬细胞TBK1的遗传和药物抑制均损害M2极化和抑制GBM 多个GBM小鼠模型的进展(Chen等人，手稿正在准备中)。在K99阶段，这是 提案将进一步研究巨噬细胞TBK1在GBM中是如何调节/激活的，以及TBK1是如何控制的 巨噬细胞M2极化。由于TAM是免疫抑制细胞，在R00阶段，该提案将 研究渗透抑制(LOX或CLOCK抑制)和/或M2极化(抑制LOX或CLOCK抑制 TBK1及其相关信号通路)可改变免疫检查点阻断的抗肿瘤反应性 (ICB)，即我将测试针对TAM和免疫检查点的潜在组合治疗策略 GBM。最后，拟议的研究将确定TBK1调节的TAM中可能起作用的关键因素 GBM进展。我建议采用一种综合策略，结合增益型和损失型方法， 体外和体内系统，以及蛋白质组和转录组分析，以鉴定和表征这些 各种因素。总而言之，该项目将揭示基底膜进展的新机制，并提供新的治疗方法 GBM的目标。

Project Summary/Abstract Glioblastoma (GBM) is the most lethal form of brain cancer in adults, with a median survival of one year following diagnosis. Unfortunately, both conventional and targeted therapies have failed to improve GBM patient survival over the last 40 years. Immune cells in the tumor microenvironment (TME) are genetically stable, and have emerged as promising therapeutic targets. Tumor-associated macrophages/microglia (TAMs) are the most abundant immune cells infiltrating the GBM TME (which can account for up to 50% of total live cells), where they exhibit an important role in promoting tumor progression and inducing immunotherapy resistance. However, the promise of TAM-targeted therapy or immunotherapy in general has not yet been realized in GBM, due in part to a limited understanding of the molecular mechanisms underlying TAM behavior and function in GBM. My postdoctoral work in the DePinho lab revealed novel mechanisms governing the recruitment of macrophages and microglia into the GBM TME. Notably, I determined that targeting macrophage/microglia infiltration via inhibition of lysyl oxidase (LOX) or circadian regulator CLOCK represents a promising therapeutic approach for GBM (Chen et al., Cancer Cell 2019; Chen at al., Cancer Discovery, under revision). Upon recruitment, macrophages/microglia exhibit a spectrum of phenotypes, including the immunostimulatory M1 phenotype and immunosuppressive M2 phenotype. It is well known that TAMs in GBM are usually polarized toward an M2 phenotype, and reprogramming TAMs from M2 to M1 phenotype could be a promising therapeutic strategy for GBM. My preliminary studies show that TANK binding kinase 1 (TBK1) is uniformly expressed by TAMs in GBM and that this druggable kinase can control macrophage polarization switch between M1 and M2 phenotypes. Both genetic and pharmacological inhibition of macrophage TBK1 impaired M2 polarization and inhibited GBM progression in multiple GBM mouse models (Chen et al., manuscript in preparation). In the K99 phase, this proposal will further investigate how macrophage TBK1 is regulated/activated in GBM and how TBK1 controls macrophage M2 polarization. Since TAMs are immune suppressive cells, in the R00 phase this proposal will investigate whether inhibition of TAM infiltration (LOX or CLOCK inhibition) and/or M2 polarization (inhibition of TBK1 and its related signaling pathways) can alter anti-tumor responsiveness to immune checkpoint blockade (ICB), i.e., I will test potential combination therapeutic strategies targeting TAMs and immune checkpoints in GBM. Finally, the proposed studies will identify the key factors from TBK1-regulated TAMs which might contribute GBM progression. I propose to employ an integrated strategy combining gain- and loss-of-function approaches, in vitro and in vivo systems, as well as proteomic and transcriptomic analysis to identify and characterize these factors. Together, this project will uncover novel mechanisms of GBM progression and offer new therapeutic targets for GBM.