Localization and Function of NKT Cells in Neuroblastoma

描述(由申请人提供)：CD1d限制的V124不变自然杀伤T细胞(NKT)在抗肿瘤免疫和免疫治疗中的潜在重要性已在多种癌症模型和最近的肿瘤学临床试验中得到证明。我们自己和其他实验室的最新发现表明，尽管NKT在大多数实体肿瘤中对肿瘤细胞没有直接作用，但它们通过与CD1d阳性的骨髓单核细胞亚群的特异性相互作用来介导抗肿瘤免疫反应。我们最近已经证明，NKT控制肿瘤生长的一种方式是通过特异性识别和杀伤肿瘤相关巨噬细胞(TAMs)，从而从肿瘤细胞中去除必要的IL-6-STAT3介导的生长支持。我们的初步数据表明，存在CCL2和CCL20介导的NKT细胞在肿瘤部位的分步定位，其中NKT与肿瘤微环境中的CD1d TAMs和未成熟树突状细胞(IDCs)相互作用。我们已经发现，单核细胞强烈上调CCL20的表达，以响应来自神经母细胞瘤(NB)细胞的低氧介导信号(S)，使我们假设肿瘤低氧调节NKT细胞的定位和天然的抗肿瘤活性。由于CCL20对IDCs也是一种有效的趋化因子，NKT细胞与肿瘤部位CD1d IDCs的相互作用可能导致保护性适应性免疫反应的产生。1)研究肿瘤缺氧调节NKT细胞定位和天然抗肿瘤活性的机制；2)研究NKT细胞与肿瘤部位CD1d髓系细胞的相互作用在针对NB的适应性抗肿瘤免疫反应机制中的作用。利用我们实验室建立的人源化NB/模型和人体外扩增的NKT，我们将评估低氧信号在CCL20依赖的NKT细胞与TAMS共定位中的作用，以及NKT细胞与TAMS的相互作用在先天NKT细胞介导的抗肿瘤活性机制中的作用。然后，利用NB9464-OVA小鼠NB模型，我们将研究NKT细胞与肿瘤部位的CD1d髓系细胞相互作用如何导致IDCs的激活和成熟，进而改善肿瘤来源的抗原呈递给CD8T细胞，并产生保护性适应性免疫。这项拟议的研究结果有望揭示NKT细胞定位于肿瘤部位的新机制及其在抗肿瘤免疫中的作用。 公共卫生相关性：拟议的调查将继续调查神经母细胞瘤中NKT细胞归巢到肿瘤部位的机制，神经母细胞瘤是儿童最常见和最致命的癌症之一。我们将在肿瘤微环境的背景下研究NKT细胞如何调节先天和适应性抗肿瘤免疫反应。这一结果可能会导致新的免疫治疗策略和临床试验，用于儿童和成人的神经母细胞瘤和其他类型的癌症。

DESCRIPTION (provided by applicant): The potential importance of CD1d-restricted V124-invariant Natural Killer T cells (NKTs) for antitumor immunity and immunotherapy has been demonstrated in multiple models of cancer as well as in recent oncology clinical trials. Recent findings by our own and other labs suggest that while NKTs lack direct effect on tumor cells in the majority of solid tumors, they mediate antitumor immune responses via specific interactions with CD1d- positive subsets of myelomonocytic cells. We have recently demonstrated that one way by which NKTs may control tumor growth is by specific recognition and killing of tumor-associated macrophages (TAMs), thereby removing essential IL-6-STAT3-mediated growth support from tumor cells. Our preliminary data suggests that there is a stepwise CCL2- and CCL20-mediated NKT-cell localization to the tumor site, in which NKTs interact with CD1d+ TAMs and immature dendritic cells (iDCs) in the context of the tumor microenvironment. We have found that monocytic cells strongly up-regulate CCL20 expression in response to hypoxia-mediated signal(s) from neuroblastoma (NB) cells, leading us to hypothesize that tumor hypoxia regulates NKT cell localization and innate antitumor activity in NB. Because CCL20 is also a potent chemoattractant for iDCs, NKT cell interaction with CD1d+ iDCs at the tumor site may lead to the generation of protective adaptive immune response. The following specific aims will test these hypotheses: 1) to examine the mechanism by which tumor hypoxia regulates NKT cell localization and innate anti-tumor activity in NB; 2) to examine the role of NKT cell interaction with CD1d+ myeloid cells at the tumor site in the mechanism of adaptive anti-tumor immune response against NB. Using established in our lab humanized NB/TAM model and human ex vivo expanded NKTs, we will evaluate the role of hypoxic signaling in CCL20-dependent NKT-cell co-localization with TAMs and the role of NKT cell interaction with TAMs in the mechanism of innate NKT cell-mediated antitumor activity. Then, using NB9464-OVA murine NB model, we will study how NKT-cell interaction with CD1d+ myeloid cells at the tumor site may lead to activation and maturation of iDCs, followed by improved presentation of tumor-derived antigens to CD8 T cells and generation of protective adaptive immunity. The results of the proposed investigation are expected to reveal novel mechanisms that govern NKT-cell localization to the tumor site and their function in the antitumor immunity. PUBLIC HEALTH RELEVANCE: The proposed investigation will continue to investigate the mechanism of NKT cell homing to the tumor site in neuroblastoma, one of the most common and deadly type of cancer in children. We will examine how NKT cells regulate innate and adaptive antitumor immune responses in the context of the tumor microenvironment. The results may lead to new immunotherapeutic strategies and clinical trials in neuroblastoma and other types of cancer in children and adults.