Investigating T Cell Egress via Lymphatic Vessels in Melanoma

项目摘要 免疫检查点阻断(ICB)治疗部分转移性黑色素瘤患者的临床疗效 催化了癌症护理方面的革命，导致其应用于各种其他类型的肿瘤。这个 然而，在肿瘤类型之间，甚至在肿瘤类型内部，对ICB的反应差异表明，另外 必须针对抑制机制来扩大这些疗法的应用。最近的生物标记物研究， 表明肿瘤微环境中细胞毒性T细胞(CTL)的存在对符合以下条件的患者来说是丰富的 可能会有反应，这表明改善肿瘤特异性CTL在肿瘤内积累的努力可能 增强对治疗的反应。目前的提案将检查调节T细胞从 黑色素瘤，并提出抑制出口作为一种新的策略，以改善T细胞保留率和反应 致ICB。我们将检验肿瘤相关淋巴管影响肿瘤内CTL池的假设 通过引导他们的出口。表达光可转换蛋白的转基因小鼠将被用于原位标记 并在体内跟踪肿瘤常驻淋巴细胞的数量。将该模型系统与转基因T细胞配对 细胞和改变的抗原配体，我们将确定抗原相遇在确定哪些细胞 从黑色素瘤微环境中的出口来描绘肿瘤中的T细胞出口如何对 肿瘤内T细胞谱系的多样性。我们的初步数据表明，肿瘤特异性T细胞 从肿瘤中排出的抗原表明，抑制肿瘤退出，以保留这些T细胞，可能会得到改善 对免疫治疗的反应。为了测试这一点，我们将确定候选趋化因子的功能意义 我们预测，CXCR4和CXCR6受体分别调节T细胞的外流和滞留。我们会 确定针对这些通路的联合药物与免疫检查点的治疗协同作用 封锁。最后，我们已经证明，在干扰素γ的介导下，用CTL干扰淋巴管串扰， 改善肿瘤控制。我们将探讨干扰素γ介导的双向串扰在调节T细胞中的作用 T细胞通过淋巴管排出，从而提示T细胞排出是一种免疫分解机制 被肿瘤微环境所吸引，以调节免疫逃避。总而言之，我们建议CTL 在黑色素瘤微环境中整合多种信号，协调它们的积累和功能 淋巴管系统。我们预测，抑制CTL出口代表了一种易于处理的临床策略 可以与针对额外免疫抑制机制的治疗协同作用(例如新陈代谢和 在此描述的机械论研究将为未来的临床翻译提供理论基础。

Project Summary The clinical efficacy of immune checkpoint blockade (ICB) in a subset of metastatic melanoma patients has catalyzed a revolution in cancer care leading to its application to a variety of other tumor types. The discrepancy in response to ICB between, and even within, tumor types, however, indicates that additional mechanisms of suppression must be targeted to expand utility of these therapies. Recent biomarker studies, indicate that presence of cytotoxic T cells (CTLs) within tumor microenvironments enriches for patients who are likely to respond, suggesting that efforts to improve intratumoral accumulation of tumor-specific CTLs might enhance response to therapy. The current proposal will examine mechanisms regulating T cell exit from melanoma and propose inhibition of egress as a novel strategy to improve T cell retention and thus response to ICB. We will test the hypothesis that tumor-associated lymphatic vessels influence intratumoral CTL pools by directing their egress. Transgenic mice expressing a photoconvertible protein will be used to in situ label and in vivo track tumor resident lymphocyte populations. Using this model system paired with transgenic T cells and altered antigen ligands, we will determine the role antigen encounter plays in determining which cells egress from melanoma microenvironments to delineate how T cell egress from tumors contributes to the diversity of the intratumoral T cell repertoire. Our preliminary data indicates that T cells specific for tumor antigens egress from tumors indicating that inhibition of tumor exit, to retain these T cells, might improve response to immunotherapy. To test this, we will determine the functional significance of candidate chemokine receptors, CXCR4 and CXCR6, which we predict regulate T cell egress and retention respectively. We will determine the therapeutic synergy of combining agents targeting these pathways with immune checkpoint blockade. Finally, we have shown that disrupting lymphatic vessel crosstalk with CTLs, mediated by IFNγ, improves tumor control. We will explore the role of IFNγ-mediated bidirectional crosstalk in regulating T cell egress through lymphatic vessels and thus propose T cell egress as a mechanism of immune resolution coopted by tumor microenvironments to mediate immune evasion. Taken all together, we propose that CTLs integrate multiple signals in melanoma microenvironments that tune their accumulation and function in concert with the lymphatic vasculature. We predict that inhibition of CTL egress represents a tractable clinical strategy that can synergize with therapies targeting additional immunosuppressive mechanisms (e.g. metabolism and exhaustion), and mechanistic studies described herein will provide the rationale for future clinical translation.