胃癌侵袭转移的分子机制尚不清楚。研究表明肿瘤来源的exosome（EXO)介导了肿瘤细胞与微环境间相互作用，本课题组前期研究发现胃癌细胞源性EXO能促进胃癌细胞增殖和迁移，并证实EXO中含有丰富的miRNA。miRNA是TLRs的配体，为阐明胃癌细胞源性EXO的miRNA通过TLRs途径促进胃癌侵袭转移，本项目将从胃癌细胞中分离纯化EXO并鉴定其中的miRNA，建立TLR8-GFP-HEK-293、荧光素酶阳性的MKN-45/luc及LNA-anti-miRNA-MKN45细胞株，围绕胃癌细胞分泌的EXO通过miRNA-TLR相互作用继而传递细胞间信息，通过“旁分泌”方式活化肿瘤微环境中的成纤维细胞、淋巴细胞和血管内皮细胞，使其分泌细胞因子等，反过来促进肿瘤细胞侵袭转移；通过“自分泌”方式，作用于肿瘤细胞本身，使其获得更强的侵袭转移能力，有助于进一步理解胃癌侵袭转移分子机制。

The morbidity and mortality of gastric cancer remains high. Tumor metastasis is a major cause of death in patients with gastric cancer. The mechanism of tumor invasion and metastasis has not been fully elucidated. It has been proved that tumor-derived exosome (EXO) mediates the interactions between tumor cell and microenvironment. In the previously experiment we found that gastric cancer cell-derived EXO can promote gastric cancer cell proliferation and migration, and confirmed that EXO is enrich in miRNA. MiRNA is ligand of TLRs. To investigate miRNA of EXO-derived from gastric cancer cell promote tumor invasion and metastasis by TLRs pathway. We will isolate EXO and miRNA from gastric cancer cells, setup TLR8-GFP-HEK-293 cell line, luciferase positive MKN-45/luc and LNA-anti-miRNA-MKN45 cells, and then we will adopt molecular biology method, Confocal microscopy scanning, 3D cell culture technology to clarify miRNA of EXO activity TLR8 pathway via auto-secretion and paracrine , which construct microenvironment to enhance tumor invasion and metastasis, promote tumor angiogenesis. This project will elucidate the molecular mechanisms of invasion and metastasis of gastric cancer from a new perspective, and provide new targets for prevention and treatment of gastric cancer.