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%，迫切需要了解其生物学。这一提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肿瘤内积累与卵巢癌临床结局的显著改善相关。我们的工作表明，内皮屏障机制存在于缺乏瘤内T细胞的预后不良肿瘤中，而趋化机制在预后良好的肿瘤中被激活，这些肿瘤被T细胞成功浸润。因此，该提案旨在了解防止肿瘤内T细胞积聚的内皮途径，并阐明这些途径如何被免疫机制规避，从而允许编排有效的T细胞抗肿瘤攻击。我们推测，在预后不良的肿瘤中，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），诱导凋亡并限制粘附T细胞的外渗。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）诱导型趋化因子中和，这些趋化因子在其促炎/抗血管生成因子的作用中向内皮传递有效信号，抑制FasL并允许T细胞的存活、外渗和瘤内积累。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T细胞归巢的内皮屏障中的作用，并研究VEGF和雌激素对其的旁分泌调节。我们将展示肿瘤微血管内皮细胞如何通过诱导细胞凋亡控制T细胞运输和防止效应T细胞外渗。我们将检测FasL在介导卵巢癌T细胞外渗的内皮屏障中的作用，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。具体目标-2：评估IFN-γ诱导型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CXCR 3发挥作用，在体外对抗VEGF和雌激素，抑制NO的产生并抑制FasL在人肿瘤微血管内皮细胞中的表达。具体目标3。检测阻断内皮细胞NO -1-FasL通路对体内T细胞归巢的影响。使用我们生成的同基因卵巢癌小鼠模型，我们将（i）确定内皮处Fas-FasL相互作用的抑制如何增强卵巢癌中的T细胞归巢，以及（ii）研究VEGF和IFN-γ诱导的趋化因子靶向如何破坏小鼠肿瘤内皮中的NO和FasL。这项工作将阐明淋巴细胞-内皮细胞合作的新的和基本的途径，调节肿瘤的免疫攻击和严重影响卵巢癌的结果。从拟议的研究中获得的结果将为开发分子工具以规避肿瘤免疫治疗的障碍产生新的想法。

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.