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

描述（申请人提供）：长期以来，肿瘤相关的慢性炎症与血液和淋巴转移有关，两者都与癌症患者生存率降低直接相关。除此之外，人们对炎症相关转移的分子基础知之甚少。旨在探究这一问题的研究可以促进有效疗法的发展，以改善患者的预后。提出的研究将为炎症促进转移的核心机制提供分子洞察力。控制炎症反应的主要途径核因子κ B (NF-？B)，由于肿瘤细胞和肿瘤微环境中的宿主细胞过度产生炎症细胞因子，在上皮性肿瘤中经常过度活跃。我们的初步研究表明，NF-？B通路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，在淋巴内皮细胞（LECs）中，VEGFR-3的表达可能受到NF-？B和淋巴特异性转录因子Prox1。符合过度活跃的NF-？B信号，我们发现NF-？b诱导因子IL-1¿、MIF和KC/CXCL1在促淋巴管生成的乳腺肿瘤细胞系中过表达，并与VEGFR-3特异性配体VEGF-C156S协同作用，协同诱导LECs增殖。总的来说，我们的发现表明NF-？B和Prox1激活VEGFR-3启动子，可能导致内皮细胞表面VEGFR-3表达增加和受体密度增加。由于VEGFR-3受体的密度可能是淋巴管生成过程中的限速步骤，我们假设NF-？B和Prox1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，我们提出以下具体目标：(1)描述NF-？B依赖性炎症介质

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. PUBLIC HEALTH RELEVANCE: Epithelial malignancies frequently have an inflammatory component that has long been linked to increased vessel formation and incidence of metastasis. We propose to delineate the molecular events that associate tumor inflammation, the formation of new lymphatic vessels and lymphatic metastasis. This information will help to identify novel targets for inhibition of lymphatic metastasis. Because metastasis is the primary cause of mortality from cancer, these studies have the potential to significantly improve health outcomes in a large number of cancer patients.