Combating the Immunosuppressive Tumor Microenvironment in Triple Negative Breast Cancer: The Role of Mitochondrial Dynamics in the Polarization of Tumor-Associated Macrophages

项目总结/摘要 三阴性乳腺癌（TNBC）是一种具有侵袭性生长和频繁转移的毁灭性疾病。 不到30%的转移性TNBC患者在诊断后存活超过5年。而其他 乳腺癌亚型具有明确的内分泌标志物，TNBC肿瘤缺乏这种特异性治疗， 目标，使循环化疗的治疗的支柱。免疫检查点阻断疗法旨在 利用TNBC固有但有限的免疫原性，尽管成功受到其他因素的限制， 肿瘤环境中的免疫抑制元素。总体目标是找到替代方案和/或 因此，本发明提供了增强TNBC肿瘤微环境中免疫介导的细胞毒性的协同方法。整体 该提案的目的是通过使巨噬细胞复极化来增强肿瘤微环境的免疫原性 从促肿瘤状态转变为具有细胞毒性的抗肿瘤状态。核心假设是线粒体融合 控制肿瘤微环境中的肿瘤相关巨噬细胞（TAM）促肿瘤功能。的 该项目的基本原理是巨噬细胞代谢决定极化命运。特别是抗肿瘤 巨噬细胞上调糖酵解，而促肿瘤巨噬细胞依赖于氧化磷酸化。作为 线粒体房子氧化磷酸化相关的途径，并作为线粒体结构的影响 氧化磷酸化效率，操纵线粒体结构可以决定极化命运。这 该提案包括原理验证研究，以证明巨噬细胞具有灵活性并且复极化 可以通过在体外和体内操纵线粒体结构来实现。沿着这条轨迹， 将通过追求两个具体目标来检验假设。目的1将确定线粒体动力学的作用 在巨噬细胞极化中。为此，我们将体外培养TNBC肿瘤巨噬细胞， 线粒体动力学，然后评估极化。目的2将确定TAM是否具有促肿瘤功能 在肿瘤微环境中的作用依赖于线粒体融合。为此，我们将评估 线粒体动力学改变的巨噬细胞对T细胞毒性、转移和血管生成的影响。的 提出的研究是创新的，因为他们将评估线粒体动力学之间的直接因果关系 和巨噬细胞极化，并且还将定义相关的体内巨噬细胞表型。该项目 重要的是因为它为操纵巨噬细胞线粒体作为治疗策略奠定了基础 以增强TNBC的肿瘤微环境免疫原性。总的来说，这些研究将有助于深入了解 控制巨噬细胞命运的机制，并在TNBC的新型免疫疗法方面取得进展。

Project Summary/Abstract Triple Negative Breast Cancer (TNBC) is a devastating disease with aggressive growth and frequent metastases. Less than 30% of patients with metastatic TNBC survive beyond five years after their diagnosis. While other breast cancer subtypes have well-defined endocrine markers, TNBC tumors lack such specific therapeutic targets, making cyclic chemotherapy the mainstay of treatment. Immune checkpoint blockade therapy aims to leverage TNBC’s inherent yet limited immunogenicity, though success has been restricted by other immunosuppressive elements in the tumor environment. The overarching goal is to find alternative and/or synergistic methods to enhance immune-mediated cytotoxicity in the TNBC tumor microenvironment. The overall objective of this proposal is to enhance tumor microenvironment immunogenicity by repolarizing macrophages out of a pro-tumor state and into a cytotoxic, anti-tumor state. The central hypothesis is that mitochondrial fusion governs tumor associated macrophages’ (TAM) pro-tumor functions within the tumor microenvironment. The rationale for this project is that macrophage metabolism defines polarization fate. Particularly, anti-tumor macrophages upregulate glycolysis while pro-tumor macrophages depend on oxidative phosphorylation. As mitochondria house oxidative phosphorylation-associated pathways, and as mitochondrial structure impacts oxidative phosphorylation efficiency, manipulating mitochondrial structure could determine polarization fate. This proposal consists of proof-of-principle studies to demonstrate macrophages are flexible and that repolarization can be achieved by manipulating mitochondrial structure in vitro and in vivo. Along this trajectory, the central hypothesis will be tested by pursuing two specific aims. Aim 1 will determine the role of mitochondrial dynamics in macrophage polarization. For this aim, we will culture TNBC tumor macrophages in vitro, manipulate mitochondrial dynamics, and then evaluate polarization. Aim 2 will determine whether TAM pro-tumor functions within the tumor microenvironment are dependent on mitochondrial fusion. In this aim, we will evaluate the effect of macrophages with altered mitochondrial dynamics on T cell cytotoxicity, metastasis, and angiogenesis. The proposed studies are innovative because they will evaluate direct causation between mitochondrial dynamics and macrophage polarization and will also define a relevant in vivo macrophage phenotype. The project is significant because it sets the foundation for manipulation of macrophage mitochondria as a therapeutic strategy to enhance tumor microenvironment immunogenicity for TNBC. Collectively, these studies will lend insight into the mechanisms that govern macrophage fate and make progress towards novel immune therapies for TNBC.