TWEAK-Fn14 Signaling in the Tumor Microenvironment

描述(申请人提供)：实体肿瘤是包含肿瘤细胞和非肿瘤细胞类型(如血管内皮细胞、成纤维细胞和巨噬细胞)的复杂组织，这些细胞之间的相互作用可以调节肿瘤的进展。例如，肿瘤细胞产生多种蛋白质，这些蛋白质以旁分泌的方式影响邻近的EC。其中一些蛋白质诱导血管生成，这对原发肿瘤的生长和转移至关重要，而另一些蛋白质则触发免疫系统细胞渗透，具有促肿瘤和抗肿瘤作用。在这项建议中，我们描述了研究细胞因子肿瘤坏死因子样弱凋亡诱导因子(TWEEP)是否在肿瘤微环境中发挥多功能作用的实验。已在人类肿瘤细胞和肿瘤相关巨噬细胞中检测到TWEAM的表达，这些细胞可能是肿瘤组织中这种细胞因子的主要来源。TWAGE通过与成纤维细胞生长因子诱导的14(Fn14)细胞表面受体结合发挥作用，是体内的血管生成因子。此外，由于TWINE治疗EC激活了核因子-B(NF-B)信号通路，并促进了促炎分子的产生，这种细胞因子在体内也可能是促炎因子。考虑到这些和其他发现，我们假设TWEEP-Fn14信号系统可能在肿瘤血管生成和炎症中发挥重要作用。具体地说，我们认为TWINE在肿瘤发展的两个阶段起作用。在第一阶段，肿瘤细胞衍生的TWINE主要作为EC激活的旁分泌调节因子，触发肿瘤血管生成和免疫细胞的渗透。在第二阶段，肿瘤间质中的免疫系统细胞，特别是血液中单核细胞来源的巨噬细胞，成为这种细胞因子的重要二级来源。这种微调蛋白还可以作用于EC，从而进一步促进肿瘤血管生成和持续的单核细胞浸润。从这两种细胞来源释放的TWEK也可能作用于肿瘤细胞本身，所有这些相互作用最终都将有助于肿瘤的生长和转移。为了检验我们的假设，我们制定了四个具体目标。这些目的是：(1)确定TWEE是否能在体外诱导促血管生成和促炎细胞反应，并研究TWEEP的活性是否依赖于核因子？B途径的激活；(2)确定TWEE进入肿瘤微环境是否能刺激血管生成、炎症和肿瘤生长，并研究这些作用是否依赖于核因子？B的激活；(3)确定肿瘤微环境中存在的TWEE是否至少部分地通过作用于非肿瘤宿主细胞而促进肿瘤生长，并确定宿主免疫细胞产生的TWEK是否有助于肿瘤生长。(4)在自发性乳腺癌模型中确定TWEAM活性是否有助于肿瘤的发生，并研究TWEKE拮抗剂是否能抑制体内肿瘤的生长。拟议的研究将为TWEE和Fn14在肿瘤微环境中的作用提供重要的、新的信息，并将为TWEE是否为人类癌症的潜在治疗靶点提供洞察力。公共卫生相关性：癌症是美国第二大死亡原因。实体肿瘤是一种复杂的组织，它既包含“转化”的肿瘤细胞，也包含“正常”的细胞类型，如排列血管的血管内皮细胞和渗入肿瘤组织的血源性免疫系统细胞。以前的研究表明，这些不同类型的细胞之间的相互作用可以调节肿瘤的进展。在这一应用中，我们建议研究一种名为TWEEP的特定细胞因子是否由肿瘤微环境中的多种细胞类型产生，并作为一种重要的刺激分子促进血管形成、肿瘤炎症，并最终导致肿瘤生长。

DESCRIPTION (provided by applicant): Solid tumors are complex tissues containing both neoplastic tumor cells and non-neoplastic cell types (e.g., vascular endothelial cells (EC), fibroblasts and macrophages) and the interactions between these cells can regulate tumor progression. For example, tumor cells produce multiple proteins that act in a paracrine manner to influence neighboring EC. Some of the proteins induce angiogenesis, which is crucial for primary tumor growth and metastasis, while others trigger immune system cell infiltration, which has both pro- and anti-tumorigenic effects. In this proposal, we describe experiments to investigate whether the cytokine tumor necrosis factor-like weak inducer of apoptosis (TWEAK) may play a multifunctional role in the tumor microenvironment. TWEAK expression has been detected in human tumor cells and tumor-associated macrophages, and these cells are likely the predominant sources of this cytokine in tumor tissue. TWEAK, acting via binding to the fibroblast growth factor-inducible 14 (Fn14) cell surface receptor, is an angiogenic factor in vivo. Additionally, since TWEAK treatment of EC activates the nuclear factor-?B (NF-?B) signaling pathway and promotes pro-inflammatory molecule production, this cytokine may also be a pro-inflammatory factor in vivo. In consideration of these and other findings, we hypothesize that the TWEAK-Fn14 signaling system may play an important role in both tumor angiogenesis and inflammation. Specifically, we propose that TWEAK acts at two phases of tumor development. In phase 1, tumor cell-derived TWEAK functions primarily as a paracrine regulator of EC activation, triggering both tumor angiogenesis and immune cell infiltration. In phase 2, immune system cells within the tumor stroma, in particular blood monocyte-derived macrophages, become an important secondary source of this cytokine. This TWEAK protein can also act on EC, thereby further contributing to tumor angiogenesis and persistent monocyte infiltration. TWEAK released from both cellular sources may also act on the tumor cells themselves, and all of these interactions will ultimately contribute to tumor growth and metastasis. Four Specific Aims have been formulated to test our hypothesis. These Aims are: (1) To determine if TWEAK can induce pro-angiogenic and pro-inflammatory cellular responses in vitro, and to investigate if TWEAK activity is dependent on NF-?B pathway activation, (2) To determine whether TWEAK delivered into the tumor microenvironment can stimulate angiogenesis, inflammation, and tumor growth, and to investigate if these effects are dependent on NF-?B activation, (3) To determine whether TWEAK present in the tumor microenvironment promotes tumor growth, at least in part, by acting on non-neoplastic host cells and to determine if TWEAK produced by host immune cells contributes to tumor growth, and (4) To determine if TWEAK activity contributes to tumorigenesis in a spontaneous mammary cancer model and to investigate whether TWEAK antagonist administration can inhibit tumor growth in vivo. The proposed studies should provide important, novel information on the role of TWEAK and Fn14 in the tumor microenvironment and will provide insight into whether TWEAK is a potential therapeutic target for human cancer. PUBLIC HEALTH RELEVANCE: Cancer is the second leading cause of mortality in the USA. Solid tumors are complex tissues containing both "transformed" tumor cells and "normal" cell types such as the vascular endothelial cells that line blood vessels and blood-derived immune system cells that infiltrate the tumor tissue. Previous studies have revealed that interactions between these different cell types can regulate tumor progression. In this application, we propose to investigate whether a particular cytokine, named TWEAK, is produced by multiple cell types in the tumor microenvironment and acts as an important stimulatory molecule contributing to blood vessel formation, tumor inflammation, and ultimately tumor growth.