Investigating T Cell Egress via Lymphatic Vessels in Melanoma

项目摘要 免疫检查点阻断（ICB）在转移性黑色素瘤患者亚组中的临床疗效 催化了癌症护理的革命，导致其应用于各种其他肿瘤类型。的 然而，肿瘤类型之间甚至肿瘤类型内部对ICB反应的差异表明， 必须针对抑制机制以扩大这些疗法的效用。最近的生物标志物研究， 表明肿瘤微环境中细胞毒性T细胞（CTL）的存在富集了 可能会有反应，这表明改善肿瘤特异性CTL的肿瘤内积累的努力可能 增强对治疗的反应。目前的提案将研究调节T细胞退出的机制， 黑色素瘤，并提出抑制出口作为一种新的策略，以改善T细胞的保留，从而响应 到ICB。我们将检验肿瘤相关淋巴管影响肿瘤内CTL库的假设 引导他们离开表达光转化蛋白的转基因小鼠将用于原位标记 并在体内追踪肿瘤驻留淋巴细胞群。利用该模型系统与转基因T 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排出，以描述T细胞从肿瘤中排出如何有助于 肿瘤内T细胞库的多样性。我们的初步数据表明，肿瘤特异性T细胞 抗原从肿瘤中排出，这表明抑制肿瘤排出以保留这些T细胞， 对免疫疗法的反应。为了验证这一点，我们将确定候选趋化因子的功能意义， 受体CXCR4和CXCR6，我们预测它们分别调节T细胞的排出和滞留。我们将 确定靶向这些通路的组合药剂与免疫检查点的治疗协同作用 封锁最后，我们已经证明，干扰IFNγ介导的CTL与淋巴管的串扰， 改善肿瘤控制。我们将探讨IFNγ介导的双向串扰在调节T细胞增殖中的作用， 通过淋巴管排出，从而提出T细胞排出作为免疫消退的机制 被肿瘤微环境吸收以介导免疫逃避。综上所述，我们建议CTL 在黑色素瘤微环境中整合多个信号，协调它们的积累和功能 淋巴管系统我们预测，抑制CTL的出口代表了一个易于处理的临床策略 其可以与靶向另外的免疫抑制机制（例如代谢和免疫抑制）的疗法协同作用。 衰竭），并且本文所述的机制研究将为未来的临床转化提供基本原理。

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.