Understanding suppression of T effector memory cells by mediators of the ovarian carcinoma microenvironment

尽管CD8+ T细胞对卵巢癌的存活有有益的影响，但肿瘤微环境，包括恶性肿瘤相关的腹膜积液（腹水），通过很大程度上未知的机制抑制了它们的功能。我们最近发现，腹水中CD8+ T效应记忆（TEM）的特异性积累与患者延长无复发生存期（RFS）有关。然而，在TEM细胞中，对T细胞活化至关重要的细胞内信号分子被卵巢癌微环境抑制，从而导致其功能障碍。本合作项目在此基础上，旨在阐明卵巢癌腹水抑制TEM的介质、机制和分子标记。为了实现这一目标，我们设计了一种基于流式细胞术、生化、遗传学、组学和生物信息学工具相结合的系统方法。我们的工作计划包括三个具体目标。(i)我们的目标是确定腹水中影响TEM信号和功能的特异性可溶性介质，以正常的外周TEM细胞为实验系统。我们将重点关注与RFS不良相关的腹水介质，以及在TATs上有受体的介质。我们将通过将特定介质的腹水水平与TEM信号的抑制相关联来寻找进一步的候选物质，这已经导致PD-L2被确定为候选物质。（ii）我们计划通过转录组学和蛋白质组学方法，描述原发性TEM细胞中传导PD-L2和腹水中其他特定介质对TEM信号传导抑制作用的信号分子和途径。我们将把获得的数据与来自腹水的TEM细胞的RNA和蛋白质谱进行比较，目的是确定临床相关的诊断标记，指示患者的T细胞“适合度”。（iii）基于这项工作，我们将致力于挽救TEM功能，从而描述新的治疗相关靶点，包括在腹水中对介质反应上调的负信号转导的敲除或药理抑制。我们期望本研究能够改善对卵巢癌患者CD8+ T细胞功能的评估，从而为新的诊断和个性化治疗方法提供基础。

Although CD8+ T cells have a beneficial impact on ovarian carcinoma survival, the tumor microenvironment, including the malignancy-associated peritoneal effusion (ascites), suppresses their function by largely unknown mechanisms. We recently identified a specific accumulation of CD8+ T effector memory (TEM) in ascites associated with a prolonged relapse-free survival (RFS) of patients. However, intracellular signaling molecules that are functionally crucial for T cell activation were suppressed by the ovarian carcinoma microenvironment in TEM cells, thereby leading to their dysfunction. The present cooperation project is based on this work and aims to elucidate the mediators, mechanisms and molecular markers of TEM suppression by ovarian carcinoma ascites. Toward this goal we have designed a systematic approach based on a combination of flow cytometric, biochemical, genetic, omics-based and bioinformatic tools. Our work program encompasses three specific objectives. (i) We aim to identify the specific soluble mediators in ascites that impinge on TEM signaling and function, using normal peripheral TEM cells as the experimental system. We will focus on mediators in ascites that are associated with poor RFS and have receptors on TATs. We will seek to identify further candidates by correlating ascites levels of specific mediators with the inhibition of TEM signaling, which already led to the identification of PD-L2 as a candidate. (ii) We plan to delineate the signaling molecules and pathways in primary TEM cells that transduce the inhibitory effect of PD-L2 and other specific mediators in ascites on TEM signaling by transcriptomic and proteomic approaches. We will compare the obtained data with the RNA and protein profiles of TEM cells from ascites with the goal to define clinically relevant diagnostic markers indicative of T cell “fitness” in patients. (iii) Based on this work, we will aim at rescuing TEM function and thus the delineation of novel therapeutically relevant targets, including the knock-down or pharmacological inhibition of negative signal transducers upregulated in response to mediators in ascites.We anticipate that this study will lead to an improved assessment of the functionality of CD8+ T cell in ovarian cancer patients, thereby providing a basis for novel diagnostic and individualized therapeutic approaches.