ECM1通过SPHK1/S1P/S1PR1通路促进乳腺癌淋巴管生成的机制研究

肿瘤进展伴随血管和淋巴管的新生，并且新生的淋巴管更有利于肿瘤细胞浸润进而形成远处播散和转移。细胞外基质蛋白1（ECM1）在多种肿瘤组织及其淋巴结转移部位中高表达，但其作用机制尚未阐明。我们前期研究发现ECM1蛋白可促进体外培养的淋巴管内皮细胞增殖，影响共培养的淋巴管内皮细胞表达1-磷酸鞘氨醇受体1（S1PR1），乳腺癌细胞中鞘氨醇激酶1（SPHK1）的表达水平与ECM1具有高度的相关性，免疫共沉淀证实ECM1可结合SPHK1；临床组织样品检测结果也表明，乳腺癌组织和转移淋巴结中淋巴管数量的增加与ECM1蛋白高表达呈正相关。本项目拟利用基因转染技术，通过细胞培养、动物体内实验以及临床组织样品的检测，系统研究ECM1与SPHK1的相互作用对1-磷酸鞘氨醇（S1P）/S1PR1通路的影响及其在乳腺癌淋巴管生成中的作用和分子机制，为乳腺癌淋巴转移的分子诊断和治疗寻找新的靶点。

Tumor progresses accompanying with angiogenesis and lymphangiogenesis. The newly born lymphatic vessels are more conducive for tumor cells to disseminate and establish distance metastases. Extracellular matrix protein 1 (ECM1) is over-expressed in various kinds of tumor tissue and their corresponding metastases in lymph nodes; while the mechanism has not yet been clarified. Our previous finding showed that ECM1 could promote proliferation in lymphatic endothelial cells, and activate the expression level of sphingosine-1-phosphate receptor 1 (S1PR1) in co-cultured lymphatic endothelial cells. Besides, the expression level of sphingosine kinase 1 (SPHK1) in breast cancer cells was closely related to ECM1; and co-immunoprecipitation assay confirmed that ECM1 could combine to SPHK1. The research results from clinical tissue samples also indicated that the elevated number of lymph vessels was positively correlated with ECM1 over-expression in breast cancer tissue and its metastases in lymph node. In this proposal, we will systematically study the functions and molecular mechanism of the combination between ECM1 and SPHK1 and their roles in the sphingosine-1-phosphate (S1P)/S1PR1 signaling pathway, and in lymphangiogenesis of breast cancer from cell culture in-vitro, animal experiment in-vivo, and clinical tissue sample examination. Our study will reveal a possibility that ECM1 may act as a novel target for diagnosis and treatment of lymphatic metastasis in breast cancer.