Effect of radiotherapy on dendritic cell subsets: implications for immunotherapy

项目总结 在回答NCI的挑衅性问题#11时，我们建议调查 放射治疗(RT)对树突状细胞(DC)和其他髓系细胞功能的影响 影响免疫疗法的疗效。鉴于它们在激活和调节新抗原方面的独特作用- 对于特异性T细胞免疫反应，我们的长期目标是利用DC进行免疫治疗。目前，有 我们理解RT对DC亚群和其他髓系细胞影响的根本机制差距 定位于肿瘤微环境(TME)。这一差距对理性的人来说是一个重要的问题 RT与免疫治疗相结合。在无肿瘤小鼠中的最新数据表明，电离辐射 (IR)不同地影响DC亚群，导致免疫原性但不耐受原性DC迅速死亡。 此外，IR改变了DC亚群的基因签名，从而改变了它们促进 抗原特异性调节性T细胞(Tregs)。因此，皮肤暴露在红外线下会促进肿瘤的生长 移植的IR后一天暴露通过依赖于耐受性DC亚群和 特雷格斯。基于这些发现，我们假设肿瘤定位的RT将导致 通过促进耐受性DC的存活和功能定位于TME中的DC亚群，这反过来将 诱导T细胞介导的耐受。我们进一步假设，这一未研究的IR对DC子集和 其他髓系细胞将显著影响RT/免疫联合治疗策略的结果。在三年内 为了达到特定的目的，我们建议对定位于TME的髓系细胞进行无偏见的描述 在使用新技术进行肿瘤靶向RT和RT/免疫治疗组合后， 和RNA-seq.我们将使用类似于患者黑色素瘤驱动突变的小鼠模型，并成像- 指导放射治疗，允许分割和立体定向给药方案，类似于临床使用的方案 练习一下。我们将把这些特征与肿瘤特异性T细胞反应的产生联系起来。我们 预计从这项提案中获得的发现将增强我们目前对DC生物学和 应对RT的功能，并对组合策略的合理设计产生积极影响。

PROJECT SUMMARY In response to NCI’s Provocative Question #11, we propose to investigate the mechanisms of action of radiotherapy (RT) on the function of dendritic cells (DCs) and other myeloid cells, and how these mechanisms affect the efficacy of immunotherapies. Given their unique role in activating and modulating new antigen- specific T cell immune responses, our long-term goal is to harness DCs for immunotherapy. Currently, there is a fundamental mechanistic gap in our understanding of the effect of RT on DC subsets and other myeloid cells localized in the tumor microenvironment (TME). This gap represents an important problem for the rational combination of RT with immunotherapies. Recent data in tumor-free mice demonstrated that ionizing radiation (IR) differentially affects DC subsets, causing the rapid death of immunogenic but not tolerogenic DCs. Furthermore, IR changes the gene signature of DC subsets and, consequently, their capacity to promote antigen-specific regulatory T cells (Tregs). Therefore, exposure of skin to IR promotes the growth of tumors transplanted one-day post-IR exposure through a mechanism dependent on tolerogenic DC subsets and Tregs. Based on these findings, we hypothesize that tumor-localized RT will induce a shift in the proportion of DC subsets localized in the TME by promoting the survival and function of tolerogenic DCs, which in turn will induce T cell-mediated tolerance. We further hypothesize that this unstudied effect of IR on DC subsets and other myeloid cells will significantly impact the outcome of RT/immunotherapy combination strategies. In three specific aims, we propose to perform an unbiased characterization of myeloid cells localized in the TME following tumor-targeted RT and RT/immunotherapy combinations using newly available technology, CyTOF, and RNA-seq. We will use mouse models that resemble melanoma-driving mutations in patients, and image- guided RT that allows for fractionation and stereotactic delivery schemes similar to those used in clinical practice. We will correlate these characterizations with the generation of tumor-specific T cell responses. We anticipate that findings obtained from this proposal will enhance our current understanding of DC biology and function in response to RT, and positively impact the rational design of combination strategies.