巨噬细胞AEG-1在下咽癌血管生成拟态形成中的作用研究

Vasculary mimicry (VM) is a new-branded type of tumor blood supply independent of angiogenesis and associated with tumor invasion, metastasis and poor prognosis in patients. We found that AEG-1, an oncogene, expressed in macrophages promotes the invasion of hypopharyngeal cancer cells and up-regulated the expression of MMP-9 which is closely related to VM, which point out that macrophage AEG-1 may participate in the process of VM. Relevant researches in this field and our priliminary studies also support this hypothesis. The aim of this study is to reveal the effect of macrophage AEG-1 on VM formation in hypopharyngeal cancer. First, we will detect the expression of macrophage AEG-1 and VM by immunohistochemical assays in hypopharyngeal cancer. Then, in vitro and in vivo test systems will be used to investigate the effect of macrophage AEG-1 on VM formation in hypopharyngeal cancer cells. Finally, we will explore the underlying mechanism. We believe that this study will provide a novel insight into the molecular mechanism of VM, and macrophage AEG-1 will be a target to develop a new treatment designed to cut off the tumor's blood supply in the future.

血管生成拟态是一种独立于血管生成的全新的肿瘤供血模式，与肿瘤侵袭、转移及患者预后密切相关。AEG-1是一个与肿瘤的侵袭转移密切相关的癌基因，申请者发现巨噬细胞AEG-1显著促进下咽癌细胞的侵袭，上调与血管生成拟态形成密切相关的MMP-9蛋白的表达，很可能参与下咽癌血管生成拟态的形成；国内外文献报道和我们前期的预实验结果也支持巨噬细胞AEG-1影响血管生成拟态形成的设想。为揭示巨噬细胞AEG-1在血管生成拟态形成中的作用，本课题拟采用免疫组化检测下咽癌标本中巨噬细胞AEG-1及血管生成拟态的表达；利用体外和体内实验分析巨噬细胞AEG-1在血管生成拟态中的作用；最后探索巨噬细胞AEG-1影响下咽癌细胞血管生成拟态的作用机制。相信我们的研究成果，对于解释血管生成拟态形成的分子机制具有重要的理论价值，同时为未来以巨噬细胞为入手点阻断肿瘤血供提供新的靶点，促成新的治疗方法。

血管生成拟态是指由侵袭性肿瘤细胞形成的血管样结构，与癌症的侵袭和转移密切相关。我们研究了巨噬细胞来源的MTDH对头颈鳞状细胞癌血管生成拟态形成的影响及其潜在机制。体外实验结果显示过表达MTDH的巨噬细胞显著促进头颈鳞状细胞癌的血管生成拟态形成，迁移和侵袭。同时过表达MTDH诱导巨噬细胞分化为M2型肿瘤相关巨噬细胞。头颈鳞状细胞癌的临床标本检测结果显示，MTDH +巨噬细胞主要位于血管生成拟态附近的肿瘤间质区域，并与淋巴结转移相关。进一步机制研究揭示，过表达MTDH的巨噬细胞通过β-catenin上调了VEGFA-165的表达和分泌，而不是其他VEGFA亚型。VEGFA-165/Flt-1轴通过p-STAT3/Twist1/VE-cadherin信号通路介导过表达MTDH的巨噬细胞在头颈鳞状细胞癌中的作用。小鼠模型结果进一步证实过表达MTDH的巨噬细胞在体内增加了血管生成拟态的形成和癌症转移。在皮下异种移植小鼠模型中，与对照组相比，HN6与过表达MTDH的巨噬细胞共同接种鼠的肿瘤免疫组化结果显示p-STAT3和Twist1表达水平升高。这项研究表明，过表达MTDH的巨噬细胞通过VEGFA-165/Flt-1轴促进了头颈鳞状细胞癌的血管生成拟态的形成，迁移、侵袭以及远处转移，并且巨噬细胞来源的MTDH可以作为头颈鳞状细胞癌的潜在治疗靶点。