oHA-LYVE1-S1P3通路调节淋巴内皮细胞孔隙改变在肿瘤淋巴转移中的作用及机制研究

The increasing of lymphatic vessel permeability is the initial step on tumor lymphatic metastasis, but specific regulatory mechanism is unknown. It has been reported that hyaluronic acid(HA) and its degradation fragments(oHA), the main component of extracellular matrix in tumor microenvironment, could play an important role in regulating vascular permeability through its receptor CD44,but whether oHA could adjust the permeability of lymphatic vessel need to be proved. Based on our previously and others study, it was found that the oHA in tumor tissue fluid and serum were positive related with tumor lymph metastasis. Our preliminary experimental results found that oHA stimulation significantly increased melanoma lymphatic metastasis. The lymphatic vessels spaces in metastases group were clearly dilated compared with metastasis negative group. These results could help for clarifing the role, the mode and the mechanism on tumor lymphatic metastasis by oHA. LYVE1 is the only HA receptor on lymphatic vessels. LYVE1 is homology with CD44, the difference is distribution different. S1P3 is the subtype of sphingosine-1-phosphate receptors. It could bind CD44 to regulate the permeability of vasular. There is no related research on regulating the permeability of lymph vessel by binding SP3 to LYVE1. According to this characteristic, our study proposed to explore the function and the mechanism of oHA on regulating tumor lymphatic metastasis through LYVE1-S1P3 pathways by vivo and vitro experiments.

淋巴管腔通透性增加是肿瘤淋巴转移过程中的初始步骤，具体调控机制不明。据报道，肿瘤微环境中细胞外基质主要成分透明质酸HA及其降解片段oHA，通过其受体CD44在调节血管通透性中发挥重要作用，但是其是否可调节淋巴管壁通透性，尚需验证。综合本课题前期及他人研究发现，肿瘤组织液及血清中oHA与淋巴转移正相关；我们预实验结果发现，oHA能够促进黑色素瘤细胞的淋巴转移，并且转移组淋巴管腔间隙较未转移组明显扩大。这些结果对阐明oHA在肿瘤淋巴转移中的作用、方式及机制，有重要的提示性。LYVE1是淋巴管壁上HA的唯一受体，与CD44同源，差别为分布不同。S1P3是内皮细胞1-磷酸鞘氨醇受体亚型，与CD44共作用调控血管渗透性。但S1P3是否与LYVE-1共作用调控淋巴管通透性，尚无相关研究。根据这一特点，本课题拟通过体内外实验研究，探索oHA是否通过LYVE1-S1P3途径调控肿瘤淋巴转移的作用及机制。

淋巴管腔通透性增加是肿瘤淋巴转移过程中的初始步骤，具体调控机制不明。据报道，肿.瘤微环境中细胞外基质主要成分透明质酸HA及其降解片段oHA，通过其受体CD44在调节血管通透性中发挥重要作用，但是其是否可调节淋巴管壁通透性，尚需验证。综合本课题前期及他人研究发现，肿瘤组织液及血清中oHA与淋巴转移正相关；我们预实验结果发现，oHA能够促进黑色素瘤细胞的淋巴转移，并且转移组淋巴管腔间隙较未转移组明显扩大。这些结果对阐明oHA在肿瘤淋巴转移中的作用、方式及机制，有重要的提示性。LYVE1是淋巴管壁上HA的唯一受体，与CD44同源，差别为分布不同。S1P3是内皮细胞1-磷酸鞘氨醇受体亚型，与CD44共作用调控血管渗透性。但S1P3是否与LYVE-1共作用调控淋巴管通透性，尚无相关研究。根据这一特点，本课题拟通过体内外实验研究，探索oHA是否通过LYVE1-S1P3途径调控肿瘤淋巴转移的作用及机制。.研究内容包括：①体内实验研究LMW-HA通过扩张淋巴管调控肿瘤细胞淋巴转移；②体外实验探索LMW-HA对肿瘤细胞跨淋巴内皮运动的影响；③细胞水平观测LMW-HA调控淋巴内皮细胞屏障功能；④分子水平探究LMW-HA调控淋巴管内皮细胞屏障功能的机理。本课题证实①肿瘤微环境异常代谢的LMW-HA能够通过破坏淋巴管内皮屏障加速肿瘤转移；②LMW-HA通过LYVE-1-S1P3通路破坏淋巴管内皮细胞间连接从而加速肿瘤淋巴转移。.本课题首次阐明LMW-HA在调控肿瘤细胞淋巴转移中的作用——打开淋巴管内皮细胞间黏附连接、紧密连接，破坏淋巴管屏障功能，为临床肿瘤淋巴转移寻找新的治疗靶点提供依据。