The role of NKG2D ligands in myeloid cell-NK cell crosstalk in cancer patients

描述(申请人提供)：长期以来，肿瘤微环境一直被认为是免疫抑制的。许多特定的蛋白质已经被鉴定出来，它们可以阻止渗透的免疫细胞的充分激活。然而，目前尚不清楚肿瘤细胞如何启动一种环境，允许在存在效应细胞的情况下存活，而效应细胞已经进化来消除它们。自然杀伤(NK)细胞是抗肿瘤反应中的一种这样的效应细胞，它分泌炎性细胞因子并直接杀死转化的细胞。有重要证据支持NK细胞在肿瘤发展的早期阶段参与消除转化细胞。在某种程度上，通过一种未知的机制，转化的细胞建立了一种方法来逃避这些细胞的识别，从而形成了实体肿瘤。一旦肿瘤形成，细胞毒性免疫细胞清除肿瘤靶点的能力就会严重减弱，从而导致肿瘤生长，并进一步抑制局部和系统免疫。髓系细胞也有广泛的募集，据信可以促进血管生成和转移，并防止免疫细胞激活。利用细胞和分子生物学技术，我们将研究胶质母细胞瘤患者肿瘤细胞、其招募的髓系细胞和NK细胞之间的复杂相互作用。我们推测，髓系细胞被招募来保护肿瘤细胞免受免疫识别，并可能成为癌症患者NK细胞的诱饵靶点。 我的研究计划详细说明了我近期和长期的职业目标，即了解控制肿瘤抑制局部和系统免疫的细胞和分子机制。我的近期目标是确定肿瘤对髓系细胞表达NKG2D配体的影响，以及这些髓系细胞如何反过来调节NK细胞的功能。我们推测，通过诱导髓系细胞表面的NKG2D配体，NK细胞杀伤从肿瘤细胞转向大量的髓系细胞的渗透。如果这些NKG2D配体阳性的髓系细胞作为NK细胞的诱饵靶点，肿瘤将创造一种物理屏障，促进生存、血管生成和转移，免受免疫系统的细胞毒细胞的影响。我们已经证明NKG2D配体阳性的髓系细胞可以作为NK细胞的靶点，肿瘤来源的可溶性蛋白可以诱导髓系细胞上NKG2D配体的表达。在这项建议中，我们将首先评估NK细胞功能对患者表达髓系细胞的NKG2D配体的反应(目标1)。接下来，我们将确定癌症患者髓系细胞中NKG2D配体的表达是否可以用作诊断或预后工具(目标2)。此外，我们将分离和鉴定肿瘤来源的可溶性蛋白或诱导髓系细胞上NKG2D配体的蛋白(目标3)。总之，这项研究工作将具有重要的临床意义，并将影响脑癌、肝细胞癌、前列腺癌和乳腺癌患者的临床治疗。 成为助理教授后，我的长期目标包括形成一个跨学科的基础和临床研究计划，以探索肿瘤如何影响患者的先天和获得性免疫反应。利用动物模型和患者样本，我的目标是发现肿瘤免疫抑制的机制，并改进目前癌症患者的免疫治疗。我将在安德鲁·帕尔萨博士和刘易斯·拉尼尔博士的指导下完成这项提案的指导阶段，并期待着作为另一所大学的助理教授完成这一项目的独立阶段。 公共卫生相关性：我的研究重点一直是确定肿瘤负担对胶质母细胞瘤患者细胞毒性免疫细胞功能的影响。这项工作将对开发利用Natural Killer和CD8+T细胞功能改进的新型患者治疗方法具有广泛的意义。在这项申请中提出的工作将确定胶质母细胞瘤免疫逃避的潜在机制。该项目还可能广泛适用于使用一种新的癌症生物标记物来监测高危患者群体。最后，该项目将确定一种新的可溶性蛋白靶点，用于胶质母细胞瘤的免疫治疗，并可能用于其他癌症患者。通过更好地了解肿瘤如何在系统和局部影响免疫系统的细胞，以及肿瘤逃避免疫识别的机制，我们希望改进抗癌斗争中的预防和治疗方法。

DESCRIPTION (provided by applicant): The tumor microenvironment has long-been known to be immunosuppressive. Many specific proteins have been identified that prevent adequate activation of infiltrating immune cells. It is not known, however, how tumor cells initiate an environment that allows survival in the presence of effector cells that have evolved to eliminate them. One such effector cell in the antitumor response is the natural killer (NK) cell, which secretes inflammatory cytokines and directly kills transformed cells. There is significant evidence to support the involvement of NK cells in the elimination of transformed cells in the early stages of tumor development. At some point, through an unknown mechanism, transformed cells establish a method to escape recognition by these cells and a solid tumor develops. Once a tumor is established, the ability of cytotoxic immune cells to eliminate tumor targets is severely diminished, allowing tumor growth and further suppression of local and systemic immunity. There is also extensive recruitment of myeloid cells, believed to promote angiogenesis and metastasis, and prevent immune cell activation. Using cellular and molecular biological techniques, we will study the complex interactions between tumor cells, the myeloid cells that they recruit and NK cells in patients with glioblastoma. We hypothesize that myeloid cells are recruited to protect tumor cells from immune recognition, and may serve as decoy targets for NK cells in patients with cancer. My research plan details my immediate and long-term career goals in understanding the cellular and molecular mechanisms that govern tumor suppression of local and systemic immunity. My immediate goals are to define the impact of a tumor on NKG2D-ligand expression by myeloid cells and how these myeloid cells can, in turn, regulate the function of NK cells. We hypothesize that through induction of NKG2D ligands on the surface of myeloid cells, NK cell killing is redirected from tumor cells to the massive infiltration of myeloid cells. If these NKG2D ligand positive myeloid cells serve as decoy targets for NK cells, a tumor will have created a physical barrier and promote survival, angiogenesis and metastasis shielded from the cytotoxic cells of the immune system. We have shown that NKG2D ligand-positive myeloid cells can be targets for NK cells, and that tumor- derived soluble proteins induce NKG2D ligand expression on myeloid cells. In this proposal, we will first evaluate NK cell function in response to NKG2D ligand expressing myeloid cells from patients (Aim 1). We will next determine if NKG2D ligand expression by myeloid cells in patients with cancer can be used as a diagnostic or prognostic tool (Aim 2). Furthermore, we will isolate and identify the tumor-derived soluble protein or proteins that induce NKG2D ligands on myeloid cells (Aim 3). Altogether, this research effort will have important clinical relevance and will influence clinical management of patients with brain, hepatocellular, prostate, and breast cancer. My long-term goals after becoming an assistant professor include forming an interdisciplinary basic and clinical research program to explore how a tumor influences innate and adaptive immune responses in patients. Using animal models and patient samples, I aim to discover mechanisms of tumor immunosuppression and develop improvements to current immunotherapy for patients with cancer. I will complete the mentored phase of this proposal under the guidance of Drs. Andrew Parsa and Lewis Lanier and look forward to completing the independent phase of this project as an assistant professor at another university. PUBLIC HEALTH RELEVANCE: The focus of my research has been aimed at defining the impact of tumor burden on the function of cytotoxic immune cells in patients with glioblastoma. This work will have broad implications in the development of novel patient therapies that capitalize on improvements of Natural Killer and CD8+ T cell function. The work proposed in this application will identify a potential mechanism of immune evasion by glioblastoma. This project may also be widely applicable to monitoring at risk patient populations using a novel biomarker for cancer. Finally, this project will identify a novel soluble protein target for immune therapy in glioblastoma and possibly in other cancer patients. By gaining a better understanding of how tumors can systemically and locally impact cells of the immune system, and mechanisms for tumor escape of immune recognition, we hope to improve preventative and therapeutic approaches in the battle against cancer.