Mitochondrial Regulation of Interferon Response in Melanoma

项目摘要 干扰素（IFN）是肿瘤免疫的中心环节，可以诱导肿瘤细胞产生促肿瘤免疫和抗肿瘤免疫 取决于癌细胞类型、产生的IFN类型（例如a、B或g）、信号持续时间 以及肿瘤微环境（TME）中的其他因素。在它们的抗肿瘤作用中，IFN诱导主要的 肿瘤细胞表面的组织相容性复合物I（MHC-I）介导CD 8 + T细胞识别， 杀人特别地，IFN还上调CD 8 + T细胞抑制性表面分子的表达， 程序性死亡配体1（PD-L1），以缓和免疫反应并避免自身免疫反应。因此，在本发明中， IFN在癌症发展中起着双重和相反的作用，使人们对IFN的作用有了更全面的了解。 它们的促肿瘤或抗肿瘤功能占主导地位的背景对于有效的癌症治疗是重要的 发展当恶性细胞失去MHC-I和抗原加工， 在一些实施方案中，IFN-γ抑制了IFN-γ呈递（APP）机制或以其他方式变得对IFN信号转导不敏感。因此，找到方法 重新激活这些通路具有显著的治疗潜力。有趣的是，赞助商最近的工作 实验室和其他人已经表明，IFN诱导的MHC-I需要线粒体电子传递链活性 表情此外，初步数据显示，体外慢性IFN刺激可降低线粒体 氧化磷酸化（OXPHOS）在黑色素瘤细胞，表明IFN信号也可以影响肿瘤 线粒体代谢为了探索肿瘤细胞的代谢状态和肿瘤细胞的生长之间的这种新的调节联系， 在小鼠黑素瘤中进行代谢靶向CRISPR敲除筛选， 细胞该筛选的结果不仅证实了在调节IFN-γ中需要线粒体OXPHOS， 信号，但也涉及脂肪酸代谢和ROS。根据这些初步数据，建议 线粒体OXPHOS，特别是线粒体燃料利用和ROS产生，可以直接调节 关键的IFN信号步骤，以及慢性IFN暴露导致线粒体代谢的变化， 促进黑色素瘤的免疫逃避。这一总体假设将通过完成两个具体的 目标。目的1是确定IFN信号通路中的哪些步骤受到线粒体OXPHOS-1的影响。 介导的调节和涉及的精确线粒体代谢信号。目标2是确定如何减少 线粒体OXPHOS和/或增加的线粒体ROS产生抑制性肿瘤 如果慢性I型IFN信号传导引起与慢性II型IFN信号传导类似的免疫抑制作用， IFN暴露。该项目将提供重要的新的见解线粒体之间的关系， 在肿瘤进展过程中的代谢和IFN反应，可能被利用来改善或重新激活抗- 肿瘤免疫应答，用于更好的癌症治疗和增强癌症免疫治疗。

PROJECT SUMMARY Interferons (IFNs) are central orchestrators of tumor immunity and can elicit both pro-tumor and anti-tumor responses depending on the cancer cell type, the type of IFN produced (e.g. a, b or g), duration of the signal, and other factors in the tumor microenvironment (TME). In their anti-tumor role, IFNs induce expression of major histocompatibility complex I (MHC-I) on the surface of tumor cells that mediates CD8+ T cell recognition and killing. Paradoxically, IFNs also upregulate expression of CD8+ T cell inhibitory surface molecules such as programmed death ligand 1 (PD-L1) to temper the immune response and avoid an autoimmune reaction. Thus, IFNs play a dual and opposing role in cancer development, making a more complete understanding of the contexts in which their pro- or anti-tumor functions predominate important for effective cancer therapy development. Immune evasion can occur when malignant cells lose MHC-I and antigen processing and presentation (APP) machinery or otherwise become desensitized to IFN signaling. Thus, finding ways to reinvigorate these pathways has significant therapeutic potential. Interestingly, recent work from the sponsor’s lab and others has shown that mitochondrial electron transport chain activity is required for IFN-induced MHC-I expression. In addition, preliminary data show that chronic IFN stimulation in vitro reduces mitochondrial oxidative phosphorylation (OXPHOS) in melanoma cells, suggesting that IFN signaling can also influence tumor mitochondrial metabolism. To probe this novel regulatory link between the metabolic state of tumor cells and their responses to IFN, a metabolism-targeted CRISPR knock-out screen was performed in mouse melanoma cells. Results from this screen not only confirmed a requirement for mitochondrial OXPHOS in regulating IFN signaling, but also implicated fatty acid metabolism and ROS. Based on these preliminary data, it is proposed that mitochondrial OXPHOS, specifically mitochondrial fuel utilization and ROS production, can directly regulate key IFN signaling steps, and that chronic IFN exposure leads to changes in mitochondrial metabolism that facilitate immune evasion in melanoma. This overall hypothesis will be tested through completion of two specific aims. Aim 1 is to determine which steps in the IFN signaling pathway are subject to mitochondrial OXPHOS- mediated regulation and the precise mitochondrial metabolic signals involved. Aim 2 is to determine how reduced mitochondrial OXPHOS and/or increased mitochondrial ROS are generating a suppressive tumor microenvironment and if chronic type I IFN signaling elicits similar immunosuppressive effects as chronic type II IFN exposure. This project will provide important new insights into the relationship between mitochondrial metabolism and IFN responses during tumor progression that might be exploited to improve or reactivate anti- tumor immune responses for better cancer treatment and augment cancer immunotherapy.