Localization and Function of NKT Cells in Neuroblastoma

描述（由申请人提供）：CD 1d限制性V124不变自然杀伤T细胞（NKT）对于抗肿瘤免疫和免疫治疗的潜在重要性已在多种癌症模型以及最近的肿瘤学临床试验中得到证实。我们自己和其他实验室的最新发现表明，虽然NKT对大多数实体瘤中的肿瘤细胞缺乏直接作用，但它们通过与骨髓单核细胞的CD 1d阳性亚群的特异性相互作用介导抗肿瘤免疫应答。我们最近已经证明，NKT可以控制肿瘤生长的一种方式是通过特异性识别和杀死肿瘤相关巨噬细胞（TAM），从而从肿瘤细胞中去除必需的IL-6-STAT 3介导的生长支持。我们的初步数据表明，有一个逐步的CCL 2和CCL 20介导的NKT细胞定位到肿瘤部位，其中NKT与CD 1d + TAM和未成熟树突状细胞（iDC）在肿瘤微环境的背景下相互作用。我们已经发现单核细胞强烈上调CCL 20表达以响应来自神经母细胞瘤（NB）细胞的缺氧介导的信号，这使我们假设肿瘤缺氧调节NB中的NKT细胞定位和先天抗肿瘤活性。由于CCL 20也是iDC的有效化学引诱物，NKT细胞与肿瘤部位的CD 1d + iDC相互作用可能导致产生保护性适应性免疫应答。以下具体目标将检验这些假设：1）检查肿瘤缺氧调节NB中NKT细胞定位和先天性抗肿瘤活性的机制; 2）检查NKT细胞与肿瘤部位CD 1d+髓样细胞相互作用在针对NB的适应性抗肿瘤免疫应答机制中的作用。使用我们实验室建立的人源化NB/TAM模型和人离体扩增的NKT，我们将评估低氧信号传导在CCL 20依赖性NKT细胞与TAM共定位中的作用以及NKT细胞与TAM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，使用NB 9464-OVA小鼠NB模型，我们将研究NKT细胞与肿瘤部位的CD 1d+骨髓细胞的相互作用如何导致iDC的活化和成熟，随后改善肿瘤衍生抗原向CD 8 T细胞的呈递并产生保护性适应性免疫。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：拟议的研究将继续研究NKT细胞归巢到神经母细胞瘤肿瘤部位的机制，神经母细胞瘤是儿童最常见和最致命的癌症之一。我们将研究NKT细胞如何在肿瘤微环境中调节先天性和适应性抗肿瘤免疫反应。这些结果可能会导致新的免疫策略和儿童和成人神经母细胞瘤和其他类型癌症的临床试验。

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.