侵袭转移是胃癌预后差的主要因素，但其机制尚未阐明。课题组前期在胃癌组织中发现NPRA与EMT和侵袭转移相关。但细胞学实验未发现其相关性。进一步研究发现趋化因子CCL2在NPRA高表达的胃癌细胞培养上清中明显升高，沉默NPRA可抑制CCL2表达。CCL2通过招募肿瘤相关巨噬细胞（TAMs）促进肿瘤EMT和侵袭转移。这提示NPRA通过调控CCL2招募TAMs促进胃癌EMT和侵袭转移。本研究拟应用体外胃癌细胞与TAMs共培养、裸鼠原位胃癌模型等手段模拟肿瘤微环境，运用激光共聚焦、qRT-PCR、Western blot、小动物成像等方法进行体内外实验研究，通过双向调节NPRA表达水平、阻断CCL2通路、加入外源性CCL2及清除体内巨噬细胞，探讨NPRA促进胃癌EMT和侵袭转移的机制。本课题将从炎症角度阐明胃癌侵袭转移的机制，为以NPRA/CCL2/TAMs为靶点的胃癌治疗提供可靠的实验基础。

Metastasis is a major factor of poor prognosis of gastric cancer (GC), but the mechanism has not been elucidated. Our previous study indicated NPRA promote EMT and metastasis in GC tissue. But the relationship did not find in GC cells. Further study showed that chemokine CCL2 increased significantly in culture supernatant of high NPRA expression GC cells, silence of NPRA inhibit CCL2 expression. CCL2 promotes tumor EMT and metastasis via tumor-associated macrophages (TAMs) recruitment. This suggests NPRA promote GC EMT and metastasis via CCL2-dependent macrophage recruitment. In this study, we will use GC cells and TAMs in vitro co-culture and model of orthotopic GC simulate tumor microenvironment, using laser scanning confocal, qRT-PCR, Western blot, small animal imaging methods and other methods, by adjusting NPRA expression, blocking CCL2 pathway, adding exogenous CCL2 and depleting macrophages, to investigate the mechanism of NPRA in EMT and metastasis of GC cells. Our study will elucidate the mechanism of GC metastasis in inflammation aspect, and provide reliable experimental basis for the treatment of GC by targeting NPRA/CCL2/TAMs.