Endothelial Regulation of T Cell Homing

描述（由申请人提供）：上皮性卵巢癌是女性妇科癌症相关死亡的最常见原因，在美国每年约有15,000例死亡。卵巢癌的总体5年生存率低于30%，因此迫切需要了解其生物学。这一建议是基于我们实验室的新证据，该证据表明淋巴细胞的跨内皮运输和瘤内积聚与卵巢癌临床结果的显着改善有关。我们的研究表明，在缺乏肿瘤内T细胞的不良预后肿瘤中存在内皮屏障机制，而在T细胞成功浸润的良好预后肿瘤中，化疗策略机制被激活。因此，本研究旨在了解阻止肿瘤内T细胞积聚的内皮途径，并阐明免疫机制如何绕过这些途径，从而实现有效的T细胞抗肿瘤攻击。我们推测，在不良预后肿瘤中，在促血管生成/抗炎旁分泌因子，包括血管内皮生长因子（VEGF）的影响下，微血管内皮上调Fas配体（FasL），诱导细胞凋亡，限制黏附T细胞外渗。我们进一步假设，在预后良好的肿瘤中，这种内皮屏障机制被干扰素- γ (ifn - γ)诱导的趋化因子中和，这些趋化因子在促炎/抗血管生成因子的作用下，向内皮传递有效的信号，抑制FasL，并允许T细胞的存活、外渗和瘤内积聚。我们建议通过以下具体目的来验证上述假设：具体目的1：确定FasL在内皮细胞屏障中对T细胞归巢的作用，并研究VEGF和雌激素对其旁分泌的调节。我们将展示肿瘤微血管内皮如何通过诱导细胞凋亡来控制T细胞运输和防止效应T细胞外溢。我们将测试FasL在卵巢癌中介导内皮细胞对T细胞外渗屏障的作用，以及VEGF和雌激素通过一氧化氮（NO）在人肿瘤内皮中的调节作用。特异性目的2：评估ifn - γ诱导趋化因子在抑制内皮细胞FasL中的作用。我们将展示ifn - γ诱导的趋化因子如何通过CXCR3作用，抵消VEGF和雌激素，抑制NO的产生，抑制体外人肿瘤微血管内皮细胞中FasL的表达。具体目标3。研究破坏内皮细胞NO - FasL通路对体内T细胞归巢的影响。利用我们建立的同基因卵巢癌小鼠模型，我们将(i)确定抑制内皮细胞中FasL -FasL相互作用如何增强卵巢癌中T细胞的归巢，以及（ii）研究靶向VEGF和ifn - γ诱导的趋化因子如何破坏小鼠肿瘤内皮中的NO和FasL。这项工作将阐明新的和基本的淋巴细胞内皮合作的途径，调节肿瘤免疫攻击和严重影响卵巢癌的结局。所提出的研究结果将为开发分子工具以规避肿瘤免疫治疗障碍提供新的思路。

DESCRIPTION (provided by applicant): Epithelial ovarian cancer is the most frequent cause of gynecologic cancer-related mortality in women, accounting for approximately 15,000 deaths in the United States yearly. The overall 5-year survival of ovarian carcinoma is less than 30%, creating a pressing need to understand its biology. This proposal is based on novel evidence from our laboratory, which suggests that transendothelial trafficking and intratumoral accumulation of lymphocytes is associated with dramatically improved clinical outcome in ovarian cancer. Our work shows that endothelial barrier mechanisms are present in poor prognosis tumors lacking intratumoral T cells, while chemo tactic mechanisms are activated in good prognosis tumors, which are successfully infiltrated by T cells. Therefore, this proposal seeks to understand the endothelial pathways preventing intratumoral T cell accumulation and elucidate how such pathways are circumvented by immune mechanisms allowing for the orchestration of an efficient T cell antitumor attack. We postulate that in poor prognosis tumors, under the influence of pro-angiogenic/anti-inflammatory paracrine factors, including vascular endothelial growth factor (VEGF), microvascular endothelium up regulates Fas ligand (FasL), inducing apoptosis and limiting the extravasations of adhering T cells. We further hypothesize that, in good prognosis tumors, this endothelial barrier mechanism is neutralized by interferon-gamma (IFN-gamma)- inducible chemokines, which, in their role of pro-inflammatory/anti-angiogenic factors, deliver potent signals to the endothelium, suppressing FasL and allowing for the survival, extravasations and intratumoral accumulation of T cells. We are proposing to test the above hypotheses through the following Specific Aims: Specific Aim 1: To determine the role of FasL in the endothelial barrier to T cell homing, and investigate its paracrine regulation by VEGF and estrogens. We will show how tumor microvascular endothelium controls T cell trafficking and prevents extravasations of effectors T cells through induction of apoptosis. We will test the role of FasL in mediating the endothelial barrier to T cell extravasations in ovarian carcinoma and its regulation by VEGF and estrogen via nitric oxide (NO) in human tumor endothelium. Specific Aim-2: To assess the role of IFN-gamma-inducible chemokines in suppressing endothelial FasL. We will show how IFN-gamma-inducible chemokines, acting through CXCR3, counteract VEGF and estrogens, suppressing NO production and inhibiting the expression of FasL in human tumor microvascular endothelial cells in vitro. Specific Aim 3. To test the effect of disrupting the endothelial NO --) FasL pathway on T cell homing in vivo. Using a syngeneic ovarian cancer mouse model that we generated, we will (i) determine how suppression of Fas-FasL interactions at the endothelium can enhance T cell homing in ovarian carcinoma, and (ii) investigate how targeting of VEGF and IFN-gamma-inducible chemokines disrupts NO and FasL in tumor endothelium in the mouse. This work will elucidate novel and fundamental pathways of lymphocyte-endothelial co-operation, which regulate tumor immune attack and critically affect the outcome of ovarian carcinoma. Results obtained from the proposed studies will generate novel ideas for the development of molecular tools to circumvent impediments to tumor immunotherapy.