Targeting an unrecognized checkpoint on T cell function in tumors

项目 总结/摘要 浸润性免疫细胞的多样性积累是几乎所有癌症的突出特征1。通过引导 由于癌症杀伤T细胞的效应子功能，免疫系统具有特异性靶向和介导癌症杀伤T细胞的能力。 清除已建立的大肿瘤2 -5.然而，T细胞效应子功能通常被限制在 肿瘤，导致疾病进展。最近关于肿瘤如何限制T细胞功能的见解已经转化为 新的癌症治疗方法，如免疫检查点阻断（αCTLA-4和PD-1）和过继免疫治疗， 大量自体肿瘤特异性T细胞的转移6，7.虽然基于免疫的疗法 在很短的时间内改变了肿瘤学的实践，这种治疗方法只在小范围内起作用。 癌症患者的百分比，因为癌症采用多种非冗余手段来逃避免疫系统。作为 我们对肿瘤诱导的T细胞功能障碍的生物驱动因素的了解仍然有限， 免疫疗法仍然不确定。 在许多肿瘤中发现大量的细胞死亡，并且与不良预后相关。细胞死亡 导致细胞内钾（K+）的释放，从而增加细胞外钾（[K+]e）， 肿瘤微环境我们首先认识到高[K+]e抑制T细胞抗肿瘤功能， 细胞因子产生，限制抗肿瘤免疫（Eil R等人，Nature 2016 & Science 2019）。机械地，K+ 介导的T细胞信号传导抑制需要PP 2A的磷酸酶活性。基因 T细胞K+转运的重编程在体外和体内转化为改善的功能。虽然这些 研究结果指出了一个未被识别的离子检查点，该检查点是由癌细胞死亡的副产品引起的，其他研究结果表明， 提出细胞死亡和组织损伤增加免疫活性是由于释放损伤相关 分子模式（DAMPs）和骨髓细胞中的炎性小体激活。然而，炎性小体信号 也被高[K+]e抑制。因此，我们的中心假设是，细胞内K+是一个中央调节器， 免疫生物学，可以利用增强T细胞抗肿瘤功能。 肝内胆管细胞癌（ICC）是原发性肝癌的第二大常见病因，并且是致命的 在几乎所有的情况下，除非手术切除，由于耐细胞毒性和靶向治疗19，20。国际刑院是 其特征是高度的基因组瘤内异质性和坏死，以及最近的 对基于T细胞的免疫疗法的反应性受到赞赏，为寻求免疫疗法提供了理想的背景。 在此提出的研究。如果成功的话，本申请中提出的研究将：1）确定 在人肝内移植背景下由细胞死亡副产物强制的免疫抑制 胆管癌; 2）测试基于增强T细胞离子转运的新型癌症治疗方法3）阐明 细胞内K+浓度控制的细胞生物学的以前未被认识的方面。

PROJECT SUMMARY/ABSTRACT A diverse accumulation of infiltrating immune cells is a prominent feature of nearly all cancers1. By directing the effector functions of cancer-killing T cells, the immune system has the ability to specifically target and mediate clearance of large established tumors2–5. However, T cell effector function is typically constrained within tumors, allowing disease progression. Recent insights into how tumors limit T cell function have translated into new classes of cancer treatments such as immune checkpoint blockade (αCTLA-4 and PD-1) and the adoptive transfer of large numbers of autologous tumor specific T cells6,7. While immune based therapies have transformed the practice of oncology over a short period of time, such treatments only work in a small percentage of patients, as cancers deploy multiple and non-redundant means to evade the immune system. As our knowledge of the biologic drivers of tumor induced T cell dysfunction remains limited, the bounds of cancer immunotherapy remain undefined. A high abundance of cell death is found in many tumors and is associated with poor prognosis. Cell death results in the release of intracellular potassium (K+), thereby increasing the extracellular potassium ([K+]e) the tumor microenvironment. We first recognized that this that high [K+]e suppresses T cell antitumor function and cytokine production, limiting antitumor immunity (Eil R et al, Nature 2016 & Science 2019). Mechanistically, K+ mediated suppression of T cell signaling required the phosphatase activity of PP2A. Genetically reprogramming of T cell K+ transport translated into improved functionality in vitro and in vivo. While these findings point to an unrecognized ionic checkpoint resulting from cancer cell death byproducts, others have proposed cell death and tissue damage to increase immune activity due to the release of damage associated molecular patterns (DAMPs) and inflammasome activation in myeloid cells. However, inflammasome signaling is also suppressed by high [K+]e. Thus,our central hypothesis is thatintracellular K+ is a central regulator of immunobiology that can be leveraged to augment T cell antitumor function. Intrahepatic Cholangiocarcinoma (ICC) is the second most common cause of primary liver cancer and is fatal in nearly all cases unless surgically resected owing to resistance to cytotoxic and targeted therapies19,20. ICC is characterized by a high degree of genomic intratumoral heterogeneity and necrosis as well as a recently appreciated responsiveness to T cell-based immunotherapy, providing an ideal context in which to pursue the research proposed herein. If successful, the research proposed in this submission will, 1) define the degree of immune suppression enforced by cell death byproducts in the context of human intrahepatic cholangiocarcinoma; 2) test novel cancer treatments based on augmenting T cell ion transport 3) clarify previously unrecognized aspects of cellular biology controlled by intracellular K+ concentration.