Mechanism and therapeutic potential of macrophage regulation in glioblastoma

项目总结/摘要 胶质母细胞瘤（GBM）是成人中最致命的脑癌形式， 诊断.不幸的是，常规和靶向治疗均未能改善GBM患者的生存率 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， 成为有前途的治疗靶点。肿瘤相关巨噬细胞/小胶质细胞（TAM）是最常见的肿瘤相关细胞。 大量免疫细胞浸润GBM TME（可占总活细胞的50%）， 在促进肿瘤进展和诱导免疫治疗抗性中显示出重要作用。但 TAM靶向治疗或免疫治疗的前景一般尚未在GBM中实现，部分原因是 对TAM在GBM中的行为和功能的分子机制的理解有限。 我在DePinho实验室的博士后工作揭示了控制巨噬细胞募集的新机制 和小胶质细胞进入GBM TME。值得注意的是，我确定通过靶向巨噬细胞/小胶质细胞浸润， 赖氨酰氧化酶（LOX）或昼夜节律调节剂CLOCK的抑制代表了一种有前景的治疗方法， GBM（Chen等人，Cancer Cell 2019; Chen等人，Cancer Discovery，under revision）.在招募时， 巨噬细胞/小胶质细胞表现出一系列表型，包括免疫刺激性M1表型， 免疫抑制M2表型。众所周知，GBM中的TAM通常朝向M2极化 表型，并且将TAM从M2重编程为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，TANK结合激酶1（TBK 1）在GBM中由TAM均匀表达 并且这种可药用激酶可以控制巨噬细胞在M1和M2表型之间的极化转换。 巨噬细胞TBK 1的遗传和药理学抑制均损害M2极化并抑制GBM 在多种GBM小鼠模型中的进展（Chen等，手稿正在准备中）。在K99阶段， 该提案将进一步研究巨噬细胞TBK 1如何在GBM中调节/激活，以及TBK 1如何控制 巨噬细胞M2极化。由于TAM是免疫抑制细胞，因此在R 00阶段，该提案将 研究抑制TAM浸润（LOX或CLOCK抑制）和/或M2极化（抑制 TBK 1及其相关信号通路）可以改变对免疫检查点阻断的抗肿瘤反应性 (ICB)，也就是，我将测试针对TAM和免疫检查点的潜在联合治疗策略， GBM。最后，拟议的研究将从TBK 1调节的TAM中确定可能有助于 GBM进展。我建议采用一种综合策略，将功能获得和功能丧失方法结合起来， 体外和体内系统，以及蛋白质组学和转录组学分析，以确定和表征这些 因素总之，该项目将揭示GBM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.