Antitumor Mechanisms of anti-CD40/CpG-activated Macrophages

描述(由申请人提供)：通过连接免疫系统细胞表面的CD40分子来激活免疫细胞，可以在荷瘤小鼠中诱导T细胞依赖和独立的抗肿瘤效应。我们最近发现，CD40和Toll样受体-9(TLR9)在抗CD40单抗(1CD40)和CpG两种免疫调节剂的联合作用下，即使在缺乏T、B和细胞溶解NK细胞的小鼠中也能诱导巨噬细胞的协同激活，并导致强大的抗肿瘤反应。由于巨噬细胞对化疗有相对的抵抗力，我们假设在体内用1CD40联合CpG治疗激活巨噬细胞将增强先前化疗在荷瘤宿主中的抗肿瘤效果。最近的初步数据支持这一假设。我们还假设，使用与CCL16趋化因子连接的肿瘤反应性单抗组成的融合蛋白将巨噬细胞靶向肿瘤微环境，将进一步增强其在已有肿瘤的小鼠中的抗肿瘤效果。我们还假设，在1CD40和CpG治疗后，已知的干扰肿瘤诱导的免疫抑制的策略将使巨噬细胞介导的抗肿瘤活性更强。本课题的目的是研究1CD40 CpG激活的巨噬细胞的抗肿瘤机制和治疗作用。具体地说，我们将通过以下四个目标来实现这一目标，包括体外和体内分析小鼠巨噬细胞及其对小鼠肿瘤，特别是B16黑色素瘤的影响：1.利用1CD40 CpG来克服肿瘤诱导的MF抑制。2.确定特异性化疗药物预处理与1CD40 CpG激活的MF的抗肿瘤作用有何协同作用。3.确定用chTNT-3/LEC FP定位1CD40 CpG-MF是否具有更好的抗肿瘤作用。4.评价1CD40 CpG联合治疗的临床前策略。这项研究将确定如何通过干扰体内肿瘤诱导的免疫抑制来增强1CD40和CpG激活的巨噬细胞的抗肿瘤反应。然后，它将确定在已有肿瘤的小鼠中进一步增强这些抗肿瘤效果的联合方案。由于小鼠和人的巨噬细胞都可以通过CD40和TLR9被激活，这些基础和临床前研究应该为未来的临床试验提供一个框架，利用这一结合化疗和巨噬细胞激活和定位方式的新策略。与公共健康相关：巨噬细胞是白细胞的重要衍生细胞，在我们防御感染和激活保护性免疫反应方面至关重要。这一建议是基于巨噬细胞也可以被激活来介导直接的抗癌作用的概念；我们假设在癌症患者中适当地激活巨噬细胞具有巨大的治疗潜力，特别是与包括常规化疗在内的其他抗癌治疗相结合。这项建议的总体目标是表征并进一步开发这一在癌症小鼠中激活巨噬细胞的新策略，其中有益的抗癌效果已经被显示出来，以确定如何最好地将其用作未来治疗人类癌症的策略。

DESCRIPTION (provided by applicant): Activation of immune system cells via ligation of their cell surface CD40 molecules can induce both T cell- dependent and independent antitumor effects in tumor-bearing mice. We have recently shown that CD40 and Toll-like receptor-9 (TLR9) ligation by the combination of two immunomodulators, anti-CD40 monoclonal antibody (1CD40) and CpG, induces synergistic activation of macrophages and results in potent antitumor responses even in mice lacking T, B and cytolytic NK cells. As macrophages can be relatively resistant to chemotherapy, we hypothesize that in vivo macrophage activation with 1CD40 plus CpG therapy will augment the antitumor effect of prior chemotherapy in tumor-bearing hosts. Recent preliminary data support this hypothesis. We also hypothesize that targeting macrophages to the tumor microenvironment using a fusion protein consisting of a tumor reactive monoclonal antibody linked to the CCL16 chemokine will further enhance their antitumor effects in mice with established tumors. We also hypothesize that strategies known to interfere with tumor induced immune-suppression will enable even greater macrophage mediated antitumor activity following 1CD40 and CpG treatment. The purpose of this project is to characterize the antitumor mechanisms and therapeutic utility of 1CD40+CpG-activated macrophages. Specifically we will accomplish this objective through the following 4 aims, which include in vitro and in vivo analyses of murine macrophages and their effects on murine tumors, particularly the B16 melanoma: 1. Utilize 1CD40+CpG to overcome tumor-induced suppression of MF. 2. Determine how pretreatment with specific chemotherapy agents synergizes with the antitumor effects of MF activated with 1CD40+CpG. 3. Determine if localizing of 1CD40+CpG-MF in the tumor using chTNT-3/LEC FP will result in better antitumor effects. 4. Evaluate preclinical strategies of combinatory 1CD40+CpG therapy. This research will determine how to augment antitumor reactivity by macrophages activated with 1CD40 and CpG by interfering with tumor induced immune suppression in vivo. It will then identify combined regimens that further enhance these antitumor effects in mice with established tumors. As both murine and human macrophages can be activated through CD40 and TLR9, these basic and preclinical studies should provide a framework for future clinical trials utilizing this novel strategy of combining chemotherapy with macrophage- activating and localizing modalities. PUBLIC HEALH RELEVANCE: Macrophages are important derivatives of white blood cells that are critical in our defense against infections and in activating protective immune responses. This proposal is based on the concept that macrophages can also be activated to mediate direct anticancer effects; we hypothesize that proper activation of macrophages in patients with cancer has great therapeutic potential, especially in combination with other anti-cancer therapies, including conventional chemotherapy. The overall goal of this proposal is to characterize and further develop this novel strategy for macrophage activation in cancerous mice, where beneficial anti-cancer effects have already been shown, in order to determine how best to use this as a future strategy for treating human cancers.