NF-kB mediated induction of VEGFR-3 and new lymphatic vessels in breast cancer

描述（由申请人提供）：长期以来，肿瘤相关慢性炎症与血行和淋巴转移有关，两者均与癌症患者生存率降低直接相关。 除了这种相关性之外，对炎症相关转移的分子基础知之甚少。 旨在询问这一问题的研究可以促进有效疗法的开发，以改善患者的预后。 这项研究将为研究促进转移的炎症机制提供分子基础。 核因子κ B（NF-？B），由于肿瘤细胞以及肿瘤微环境中的宿主细胞过度产生炎性细胞因子，在上皮肿瘤中经常过度活跃。 我们的初步研究表明，激活NF-？B途径增加血管内皮生长因子受体-3（VEGFR-3）的表达，VEGFR-3是驱动淋巴管生成和淋巴转移的主要受体。 也有证据表明，在淋巴管内皮细胞（LECs）VEGFR-3的表达可能是由NF-？B和细胞特异性转录因子Prox 1。 与过度活跃的NF-相符？B信号，我们发现NF-？B-诱导因子IL-1？MIF和KC/CXCL 1在促淋巴管生成乳腺肿瘤细胞系中过表达，并与VEGFR-3特异性配体VEGF-C156 S协同作用，协同诱导LEC增殖。 总的来说，我们的研究结果意味着NF-？B和Prox 1激活VEGFR-3启动子，可能导致VEGFR-3表达增加和LEC表面受体密度增加。 因为密度的VEGFR-3受体是一个可能的限速步骤，在淋巴管生成，我们假设NF-？B和Prox 1介导的VEGFR-3转录增加对于诱导肿瘤淋巴管生成至关重要。 为了验证这一假设，我们提出了以下具体目标：（1）阐明NF-？B依赖性炎症介质 IL-1、MIF和KC/CXCL 1对VEGFR-3表达、VEGFR-3信号通路激活和LEC刺激的影响; B介导的VEGFR-3表达调节;（3）确定宿主和肿瘤来源的IL-1、MIF和KC/CXCL 1细胞因子在体内诱导乳腺癌相关淋巴管生成和淋巴转移中的作用。 预期这些目标的成功完成将为设计特异性靶向肿瘤淋巴管生成和转移的疗法提供必要的分子基础，从而推进我们提高癌症患者生存率的总体目标。

DESCRIPTION (provided by applicant): Tumor-associated chronic inflammation has long been linked to both hematogenous and lymphatic metastases, both of which directly correlated with reduced cancer patient survival. Beyond this correlation, little is known about the molecular basis of inflammation-associated metastasis. Studies designed to interrogate this question could advance development of effective therapies to improve patient outcomes. The proposed investigation will provide molecular insight into central mechanisms of inflammation that promote metastasis. The main pathway controlling inflammatory responses, Nuclear Factor kappa B (NF-?B), is frequently hyperactive in epithelial tumors due to over-production of inflammatory cytokines by neoplastic cells as well as by host cells within the tumor microenvironment. Our preliminary studies demonstrate that activation of the NF-?B pathway increases expression of vascular endothelial growth factor receptor-3 (VEGFR-3), the main receptor driving lymphangiogenesis and lymphatic metastasis. Evidence is also presented that in lymphatic endothelial cells (LECs) VEGFR-3 expression might be regulated by both the p50 subunit of NF-?B and the lymphatic-specific transcription factor, Prox1. Consistent with hyperactive NF-?B signaling, we found that NF-?B-inducing factors IL-1¿, MIF and KC/CXCL1 are overexpressed in pro-lymphangiogenic breast tumor lines and act in concert with a VEGFR-3 specific ligand, VEGF-C156S, to synergistically induce LECs proliferation. Collectively, our findings imply that NF-?B and Prox1 activate the VEGFR-3 promoter, likely leading to increased VEGFR-3 expression and higher receptor density on the surface of LECs. Because the density of VEGFR-3 receptors is a likely rate-limiting step during lymphangiogenesis, we hypothesize that NF-?B and Prox1 mediated increase of VEGFR-3 transcription is crucial for induction of tumor lymphangiogenesis. To test this hypothesis, we propose the following Specific Aims: (1) Delineate the effects of NF-?B dependent inflammatory mediators IL-1¿, MIF and KC/CXCL1 on VEGFR-3 expression, activation of VEGFR-3 signaling and LEC stimulation in vitro; (2) Delineate the role of Prox1 in NF-?B-mediated regulation of VEGFR-3 expression; (3) Define the role of host and tumor-derived IL-1¿, MIF and KC/CXCL1 cytokines in induction of breast cancer-associated lymphangiogenesis and lymphatic metastasis in vivo. Successful completion of these aims is anticipated to provide the molecular basis imperative for the design of therapies specifically targeting tumor lymphangiogenesis and metastasis, thus advancing our overall goal of improving cancer patient survival.