T cell expressed miR-155 promotes antitumor immunity and immune checkpoint blockade responses in colon cancer through repression of Ship1

项目摘要/摘要 结直肠癌(CRC)是全球第二大致死性癌症，发病率和死亡率居第三位 美国所有癌症的比率。50岁以下的患者越来越多地出现晚期- CRC期，在目前的治疗标准下，五年存活率为14%。因此，新的治疗方法 目前正在探索免疫检查点封锁(ICB)等选项。T细胞失活通常发生在 肿瘤，导致免疫反应差。ICB常常通过阻断诱导强大的抗肿瘤免疫反应 微卫星不稳定性高转移性结直肠癌患者T细胞失活的研究如此高的响应率 是由于免疫细胞介导的炎症性肿瘤微环境(TME)在这些患者。然而，a 大多数结直肠癌患者存在免疫抑制的TME，导致ICB无效。因此，从长远来看， 本项目的目标是了解和调节T细胞亚群以改善结直肠癌患者的ICB反应 通过非编码RNA对ICB治疗通常无反应的患者。这项提议的目的是 通过操纵T细胞microRNA将免疫细胞耗竭的结肠肿瘤转变为免疫细胞丰富的肿瘤- 155(miR-155)，一种经典的促炎microRNA(MiRNA)，及其靶点。中心假设是 T细胞microRNA-155通过以下途径促进结肠癌中Th1和细胞毒性T淋巴细胞(CTL)丰富的TME 抑制Th2细胞极化，促进ICB应答。我们还假设Ship1，一个典型的MIR- 155靶点，通过增加Th1细胞和CTL产生干扰素γ来促进促炎TME 肿瘤生长。这一假设是基于与人类结直肠癌T细胞基因特征相关的初步数据 MiR-155，这是小鼠抗肿瘤免疫和ICB抗结肠癌所必需的 模特们。这项工作的基本原理是，通过改变T细胞miRNAs或其下游靶标，我们可以促进 炎性免疫细胞渗入结肠TME。随后，可以在冒号中引发ICB响应 癌症患者，无论MSI状态如何。 根据我们的初步数据，中心假设将通过两个具体目标进行检验：1)确定 在结肠癌小鼠模型中，T细胞miR-155是否抑制Th2细胞极化，促进ICB反应， 以及2)确定抑制T细胞miR-155靶点SHIP-1是否促进抗肿瘤免疫，增强 ICB反应，并限制肿瘤生长。本研究具有创新性，旨在研究MSI-H相关的miR- 155和Ship-1在T细胞背景下的表达，这是ICB治疗的主要靶点。拟议的研究 具有重要意义，因为它解决了对新的治疗靶点的需求，以增强非ICB反应 有反应的结直肠癌患者。

PROJECT SUMMARY/ABSTRACT Colorectal cancer (CRC) is the second deadliest cancerglobally and has the third-highest incidenceand mortality rate of all cancers in the United States. Patients under 50 years old are increasingly presenting with advanced- stage CRC, which has a five-year survival rate of 14% with the current standard of care. Thus, new treatment options, such as immune checkpoint blockade (ICB), are being explored. T cell inactivation often occurs in tumors, leading to a poor immune response. ICB often induces a robust antitumor immune response by blocking T cell inactivation in patients with microsatellite instability-high (MSI-H) metastatic CRC. This high response rate is due to an immune cell-mediated inflammatory tumor microenvironment (TME) in these patients. However, a majority of CRC patients have an immune-suppressive TME, rendering ICB ineffective. As such, the long-term goal of this project is to understand and to modulate the T cell compartment to improve ICB responses in CRC patients that are typically non-responders to ICB therapy via non-coding RNAs. The objective of the proposal is to convert immune cell-depleted colon tumors into immune cell-enriched ones by manipulating T cell microRNA- 155 (miR-155), a classically proinflammatory microRNA (miRNA), and its targets. The central hypothesis is that T cell microRNA-155 promotes a Th1 and cytotoxic T lymphocyte (CTL)-enriched TME in colon cancer by inhibiting Th2 cell polarization and promoting ICB response. We also hypothesize that Ship1, a canonical miR- 155 target, promotes the proinflammatory TME by increasing IFNγ production fromTh1 cells and CTLs to reduce tumor growth. This hypothesis is based on preliminary data that correlate T cell gene signatures in human CRC with miR-155, which is necessary for antitumor immunity and ICB responses against colon cancer in our mouse models. The rationale for this work is that by altering T cell miRNAs or their downstreamtargets, we can promote inflammatory immune cell infiltration into the colon TME. Subsequently, an ICB response can be elicited in colon cancer patients regardless of MSI status. Based on our preliminary data, the central hypothesis will be tested through two specific aims: 1) determine whether T cell miR-155 inhibits Th2 cell polarization, promoting ICB responses in a mouse model of colon cancer, and 2) determine whether inhibiting SHIP-1, a T cell miR-155 target, promotes antitumor immunity, enhances ICB responses, and restricts tumor growth. This study is innovative as it aims to study MSI-H associated miR- 155 and SHIP-1 expression in the context of T cells, the primary target of ICB therapy. The proposed research is significant because it addresses the need for new therapeutic targets to potentiate ICB responses in non- responsive CRC patients.