Role of the Fractalkine Signaling in EOC

描述（由申请人提供）：上皮性卵巢癌（EOC）是妇科恶性肿瘤死亡的主要原因。腹膜转移是腹膜癌治疗中尚未解决的临床难题。目前使用的治疗方法不是针对EOC转移的，并且在保持患者缓解方面效率低下。因此，靶向促转移途径可以提供更好的机会来提高生存率。在我们寻找新靶点的方法中，我们在满足以下标准的通路中进行了搜索：1)在EOC进展中起主要作用；2)已被证明是治疗其他疾病的有效靶点。趋化因子信号传导对癌细胞迁移、增殖、粘附和侵袭至关重要，也就是说，这些特性是成功发展转移所必需的。在本应用中，我们将描述fractalkine通路在EOC转移发展中的关键作用，并确定其主要参与者趋化因子fractalkine （CX3CL1）及其受体fractalkine CX3CR1作为未来治疗旨在预防和延缓转移扩散的新靶点的潜在用途。我们的初步数据显示，原发和转移的人类EOC标本中CX3CR1呈高度阳性，而未患病对照者的正常卵巢表面上皮中CX3CR1呈阴性。此外，我们发现EOC细胞可以依赖cx3cr1的方式迁移到CX3CL1。此外，在我们的先导实验中，在EOC细胞中CX3CR1表达的增加导致异种移植EOC小鼠模型中形成更多更大尺寸的肿瘤。趋化因子是很有希望的药物靶点。此外，趋化因子受体是G蛋白偶联受体，这一类蛋白质是有效的药物靶点，约占FDA批准药物的30%。这些药物已经在临床中被证明是有效的，针对CX3CL1和CX3CR1的新药目前正在开发中。CX3CL1/CX3CR1是一个独特的合适的药物靶点，因为趋化因子与其受体之间的相互作用是非常特异性的，并且没有其他趋化因子配体激活CX3CR1，而其他趋化因子/受体对表现出高交叉反应性。因此，针对CX3CR1或CX3CL1的药物可能只影响CX3CL1/CX3CR1轴。根据我们的初步数据和已发表的文献，我们的假设是CX3CL1/CX3CR1轴是转移性EOC细胞归巢到腹膜和通过支持细胞粘附和迁移促进转移扩散所必需的。为了验证这一假设，我们提出了两个目标。在Aim 1中，我们将使用细胞培养模型和我们先前开发的EOC转移特异性培养条件，确定CX3CL1/CX3CR1在腹膜间皮细胞和潜在的细胞外基质粘附中的需求。粘连是腹膜转移定殖的主要初始步骤之一。在目的2中，我们将使用异种移植小鼠模型来描述EOC在体内转移发展中对CX3CL1/CX3CR1的需求。

DESCRIPTION (provided by applicant): Epithelial ovarian carcinoma (EOC) is a leading cause of death from gynecologic malignancies. Peritoneal metastasis is an unsolved clinical problem in treatment of EOC. Currently used therapeutic approaches are not specific to EOC metastasis and are inefficient at keeping patients in remission. Thus, targeting the pro-metastatic pathways could provide improved opportunities to increase survival. In our approach to find new targets we searched among pathways that satisfy the following criteria: 1) play a major role in EOC progression; 2) have proven to be effective targets for treatments of other diseases. Chemokine signaling is essential for cancer cell migration, proliferation, adhesion, and invasion, i.e., properties that are necessary for a successful development of metastasis. In this application we will characterize fractalkine pathway as crucial for the development of metastasis in EOC and determine potential usefulness of its main players, chemokine fractalkine (CX3CL1) and its receptor, fractalkine CX3CR1, as novel targets for future therapies aimed at prevention and retardation of metastatic spread. Our preliminary data show that primary and metastatic specimens of human EOC are highly positive for CX3CR1, while normal ovarian surface epithelium in non-diseased control subjects is CX3CR1-negative. Moreover, we show that EOC cells can migrate in CX3CR1-dependent manner to CX3CL1. Furthermore, in our pilot experiments increase of CX3CR1 expression in EOC cells led to formation of more tumors of larger size in a xenograft EOC mouse model. Chemokines are promising drug targets. Moreover, chemokine receptors are the G protein coupled receptors, a class of proteins that are effective drug targets covering an estimated 30% of FDA approved drugs. Such drugs have been proven to work in the clinic, and new drugs against CX3CL1 and CX3CR1 are currently under development. CX3CL1/CX3CR1 is a uniquely suitable drug target because the interaction between the chemokine and its receptor is very specific, and there are no other chemokine ligands activating CX3CR1, in contrast to other chemokine/receptor pairs that display high cross-reactivity. Thus, drugs directed at either CX3CR1 or CX3CL1 will likely to affect only the CX3CL1/CX3CR1 axis. Based on our preliminary data and published literature our hypothesis is that CX3CL1/CX3CR1 axis is required for homing metastatic EOC cells to the peritoneum and facilitation of metastatic spread by supporting cell adhesion and migration. To test this hypothesis we propose two aims. In Aim 1 we will determine the requirement of CX3CL1/CX3CR1 in adhesion to peritoneal mesothelial cells and underlying extracellular matrix using cell culture models and previously developed by us EOC metastasis-specific culture conditions. Adhesion is one of the main initial steps of the metastatic colonization of the peritoneum. In Aim 2 we will characterize the requirement for CX3CL1/CX3CR1 in development of EOC metastasis in vivo using a xenograft mouse model.