Distinct spatiotemporal dynamics of CD8+ T cell-derived cytokines in the tumor microenvironment (5892). Distinct spatiotemporal dynamics of CD8+ T cell-derived cytokines in the tumor microenvironment (5892)

Tumors consist of a dynamic collection of interacting tumor cells, stromal cells and immune cells. In addition to the direct cell-cell interactions that are mediated by receptor-ligand interactions, cells in the tumor microenvironment (TME) influence each other through the secretion and sensing of soluble mediators, such as cytokines and chemokines. While signaling of the interferon γ (IFNγ) and tumor necrosis factor α (TNFα) cytokines has been shown to be critical in anti-tumor immune responses in a number of settings, our understanding of the spatiotemporal behavior of these cytokines in the TME is limited. Here, we describe a single cell transcriptome-based approach to infer which single or combined signals an individual cell has received and estimate the timing of such exposure. Using this technology, we demonstrate that, contrary to expectations, CD8+ T cell-derived IFNγ is the dominant modifier of the TME relative to TNFα. Furthermore, we demonstrate that cell pools that show abundant IFNγ sensing are characterized by decreased TGFβ signaling, consistent with IFNγ-mediated remodeling of the TME. Collectively, these data provide evidence that CD8+ T cell-secreted cytokines should be distinguished into local and more global modifiers of tumor tissue, and describe a broadly applicable approach to dissect cytokine and chemokine modulation of the tumor microenvironment. Overall design: Murine NRAS mutated melanoma-cells (NMM) exposed to various (combinations of) cytokines (TNFa, IFNy, tumor-cell T-cell co-culture supernatant) for 4 different durations (2, 6, 12, 24 hours of continuous stimulation)

肿瘤是由相互作用的肿瘤细胞、基质细胞与免疫细胞共同组成的动态复合体。除受体-配体相互作用介导的直接细胞间互作外，肿瘤微环境（TME）内的细胞还可通过分泌与感知细胞因子、趋化因子等可溶性介质实现相互调控。尽管多项研究已证实，干扰素γ（IFNγ）与肿瘤坏死因子α（TNFα）的信号转导在多种场景下的抗肿瘤免疫应答中发挥关键作用，但目前学界对这两种细胞因子在肿瘤微环境中的时空动态行为仍了解有限。本研究开发了一种基于单细胞转录组的分析方法，可推断单个细胞所接收的单一或组合信号，并估算该细胞暴露于这些信号的时间节点。借助该方法，我们的研究结果与预期相悖：相较于TNFα，CD8+ T细胞分泌的IFNγ是肿瘤微环境的主要调控因子。此外，我们发现呈现高水平IFNγ感知的细胞群，其转化生长因子β（TGFβ）信号转导水平显著降低，这与IFNγ介导的肿瘤微环境重塑过程相符。综上，本研究数据表明，CD8+ T细胞分泌的细胞因子可分为肿瘤组织的局部调控因子与全局调控因子两类；同时本研究也提供了一种可广泛应用的分析框架，用于解析细胞因子与趋化因子对肿瘤微环境的调控作用。实验设计：将携带NRAS突变的小鼠黑色素瘤细胞（NMM）分别暴露于多种细胞因子（TNFα、IFNγ、肿瘤细胞-T细胞共培养上清液）及其组合中，并设置4种不同的刺激时长（持续刺激2、6、12、24小时）。