Tumor-expressed wnts and dendritic cell tolerance in cancer immune evasion

描述（由申请人提供）：树突状细胞（DC）耐受与肿瘤免疫逃避之间的关系已经建立；然而，在肿瘤环境中控制耐受原性与免疫刺激DC功能平衡的效应分子和机制尚不完全清楚。在这个提议中，我假设在许多人类癌症中上调的wnt蛋白可以直接作用于DC以促进耐受性，并且wnt依赖的DC耐受性反应有助于肿瘤免疫逃避。为了解决这些假设，我将确定肿瘤表达的wnt如何影响DC表型和免疫功能，并将测试DC特异性wnt信号在肿瘤免疫逃避中的作用。首先，将从小鼠淋巴结分离的DC用重组规范化（wnt3a）或非规范化wnt5a处理，并评估DC成熟标记物表达、细胞因子产生和Treg表型诱导。将阐明DC中的Wnt信号事件，以确定参与Wnt诱导DC耐受性的关键效应分子。其次，具有典型wnt信号（DC特异性¿-catenin缺失）靶向树突状细胞特异性缺陷的小鼠将被用来确定肿瘤表达的wnt在抗肿瘤反应中DC编程的作用。将使用wnt编码或控制载体转导的肿瘤。将比较dc特异性¿-catenin缺陷小鼠与对照小鼠的肿瘤浸润淋巴细胞群、肿瘤免疫的诱导以及对肿瘤生长的免疫效应。本研究的发现将明确wnt调控DC耐受性表型的作用和机制，并将批判性地验证肿瘤表达的wnt对树突状细胞的耐受性作用可能是肿瘤免疫逃避的重要机制的假设。这些发现表明，靶向肿瘤表达的wnt蛋白可能有助于肿瘤治疗的免疫方法。

DESCRIPTION (provided by applicant): A relationship between dendritic cell (DC) tolerance and tumor immune evasion has been established; however, the effector molecules and mechanisms that control the balance of tolerogenic vs immune stimulatory DC function in the tumor environment are incompletely understood. In this proposal I hypothesize that wnt proteins, which are upregulated in many human cancers, can act directly on DCs to promote tolerance, and that the wnt-dependent DC tolerogenic responses contribute to tumor immune evasion. In an effort to address these hypotheses I will determine how tumor-expressed wnts influence DC phenotype and immune function, and will test the role of DC-specific wnt signaling in tumor immune evasion. First, DCs isolated from mouse lymph nodes will be treated with recombinant canonical (wnt3a) or non-canonical wnts (wnt5a), and DC maturation marker expression, cytokine production, and Treg phenotype induction will be assessed. Wnt signaling events in DCs will be elucidated to determine key effector molecules involved in wnt-induced DC tolerance. Second, mice with a targeted dendritic cell-specific deficiency in canonical wnt signaling (DC-specific ¿-catenin deletion) will be used to determine the role of DC programming by tumor-expressed wnts in the anti- tumor response. Tumors transduced with wnt-encoding or control vectors will be used. Tumor infiltrating lymphocyte populations, induction of tumor immunity, and immune effects on tumor growth will be compared in the DC-specific ¿-catenin deficient vs control mice. The findings from this proposal will define the role and elucidate mechanisms of wnt regulation of the DC tolerogenic phenotype, and will critically test the hypothesis that the tolerogenic effect of tumor-expressed wnts on dendritic cells can be a significant mechanism for tumor immune evasion. Such insights would suggest that targeting tumor-expressed wnt proteins could contribute to immunologic approaches to tumor therapy.