癌周LEC表达CXCL1促进胃癌淋巴道转移的分子机制

Gastric cancer spreads mainly through lymphatic vessels, of which the mechanism necessitates further study.Our previous studies showed a novel finding that expression of CXCL1 in the afferent lymphatic endothelial cells (LEC) was increased after gastric cancer cell arrived at the sentinel lymph node, and further found that its receptor CXCR2 was up-regulated in gastric cancer and positively related to lymphangiogenesis. However, the precise molecular mechanism by which CXCL1 signal promotes lymph node metastasis in gastric cancer remains unclear. This project will firstly confirm up-regulation of CXCL1 in peritumoral LEC in clinical specimens, followed by detecting the effects of CXCL1 on gastric cancer cell adhesion, migration and invasion.And then we will investigate whether LEC can release CXCL1 and promote gastric cancer cell adhesion in an integrin β1-dependent way in the flow chamber adhesion experiments.Furthermore, we will test whether CXCL1 can enhance the invasion and metastasis of gastric cancer cells by activating the integrin β1-FAK-MAPK pathway. Finally, we will prove that CXCL1 from LEC promotes lymphatic metastasis in animal models.This project aims to explore the molecular mechanisms by which CXCL1 expressed by peritumoral LEC promotes the lymphatic metastasis of gastric cancer, which may provide a potential treatment target for gastric cancer.

胃癌主要经淋巴道转移，阐明其机理意义重大。我们前期从一个全新的角度发现，胃癌细胞转移到前哨淋巴结后，输入淋巴管内皮细胞（LEC）CXCL1表达升高，其受体CXCR2在胃癌中表达上调，并与淋巴管新生成正相关，但CXCL1 促进胃癌淋巴道转移的机制仍需进一步明确。本项目拟在前期研究的基础上，首先在临床标本中证实癌周LEC的CXCL1 表达升高；进一步从细胞水平分析CXCL1对胃癌细胞粘附、迁移和侵袭等生物学功能的影响；然后通过流动腔实验证明LEC释放CXCL1，并通过β1-integrin介导胃癌细胞粘附；继而证明CXCL1通过Integrin-FAK-MAPK信号通路促进胃癌细胞的侵袭和迁移；最后采用动物模型验证LEC来源的CXCL1促进胃癌淋巴结转移。本项目旨在阐明癌周LEC表达CXCL1促进胃癌淋巴道转移的分子机制，为抑制胃癌淋巴道转移的治疗提供新的干预靶点。

胃癌主要通过淋巴道转移，阐述清楚胃癌发生淋巴道转移的分子机制对于理解胃癌进展和研究新的治疗方法至关重要；我们前期研究发现胃癌细胞与淋巴管内皮细胞（LEC）之间的相互作用在影响胃癌淋巴管转移方面有着重要作用；但是，淋巴管内皮细胞促进胃癌转移的具体分子机制还不清楚；首先，本研究证实胃癌组织中CXCL1的表达明显上调，CXCL1表达水平与T分期和N分期密切相关；阳性表达CXCL1预示着更短的总的五年生存率；其次，胃癌细胞过表达CXCL1后，细胞的迁移和成瘤能力得到明显增强；此外，过表达的CXCL1可以通过上调胃癌细胞的VEGF促进肿瘤间质内的血管新生；同时，本研究还探讨了淋巴管内皮细胞来源的CXCL1对胃癌淋巴道转移的影响；运用荧光双标记技术和磁珠分选技术精确地检测了淋巴管内皮细胞中CXCL1的表达，发现胃癌相关淋巴管内皮细胞（T-LEC）中CXCL1的表达较正常淋巴管内皮细胞中的表达明显升高；体内和体外实验证实淋巴管内皮细胞来源的CXCL1通过激活integrin β1/FAK/AKT通路促进胃癌细胞侵袭、迁移、黏附和淋巴道的转移。总之，我们的结果显示肿瘤细胞来源的和淋巴管内皮细胞来源的CXCL1在促进胃癌进展方面发挥重要作用；本实验结果为CXCL1作为胃癌靶向治疗的靶点提供了理论的基础和依据。