重组人信号素3A抑制胃癌血管生成及其机制

目的 探讨信号素3A（Sema3A）及其受体神经激-1（NRP-1）在胃癌中的表达及其与微血管密度（MVD）的相关性；并探讨重组人Sema3A对胃癌血管生成的影响及其相关的机制。方法 选取40例手术切除胃癌组织及其癌旁正常组织，免疫组织化学法检测组织中Sema3A、NRP-1的表达及MVD。ELISA检测胃癌患者组及正常对照组血清Sema3A的表达水平。Western blotting检测5株胃癌细胞系（MGC-803、HGC-27、MKN-28、SGC-7901、MKN-45）、人正常胃黏膜细胞（GES-1）中Sema3A和NRP-1的表达。应用Transwell小室构建非接触式体外共培养体系，小管形成实验初步研究不同浓度重组人Sema3A对胃癌血管生成的影响；Western blotting检测共培养体系中血管内皮生长因子受体2（VEGFR2）、NRP-1的表达水平。结果 胃癌组织、细胞和患者血清中Sema3A的表达显著低于对照组（P<0.05），胃癌组织和MKN 28细胞中的NRP-1表达明显升高（P<0.05），两者均与胃癌TNM分期相关（P<0.05），且Sema3A与微血管密度存在负相关（P<0.05）。在体外共培养体系中，重组人Sema3A处理组人脐静脉内皮细胞（HUVEC）小管形成能力下降，且具有浓度依赖性；重组人Sema3A可下调VEGFR2蛋白的表达。结论 Sema3A在胃癌组织、细胞和患者血清中均表达降低，与微血管密度成负相关，重组人Sema3A具有体外抑制胃癌血管生成的作用，可能与下调VEGFR2蛋白表达有关。

Inhibitory effect of recombinant human semaphorin 3A on angiogenesis of gastric cancer and the associated mechanisms#br#

Objective To investigate the expression of semaphorin 3A (Sema3A) and its receptor neuropilin-1 (NRP-1) in gastric cancer and its correlation with microvessel density (MVD)，and then to explore the effect of recombinant human Sema3A on angiogenesis of gastric cancer and the associated mechanisms.Methods Forty cases of gastric cancer tissues and its corresponding adjacent normal tissues were used to detecte the expression of Sema3A, NRP-1 and MVD in tissues by immunohistochemistry method . The expression level of Sema3A in serum of gastric cancer patient group and normal control group were measured by Enzyme-linked immuno-sorbent assay (ELISA). Western blotting was used to detect the expression of Sema3A and NRP-1 in five gastric cancer cell lines (MGC-803,HGC-27,MKN-28,SGC-7901,MKN-45) and human gastric mucosal epithelial cell (GES-1). Transwell chamber was used to construct non-contact in vitro co-culture system, in which the effects of different concentrations of recombinant human Sema3A on angiogenesis in gastric cancer were analyzed by tube formation assay preliminarily. The expression levels of vascular endothelial growth factor receptor 2 (VEGFR2) and NRP-1 in co-culture system were detected by Western blotting.Results The expression levels of Sema3A in gastric cancer tissues, cell lines and patient serum were significantly lower than that in the control group（P<0.05）, while the expression of NRP-1 in gastric cancer tissues and MKN-28 cells was significantly increased, and both of them were associated with TNM staging of gastric cancer（P<0.05）. In vitro co-culture system, The tube forming abilities of human umbilical vein endothelial cell (HUVEC) were decreased in recombinant human Sema3A treated group, and this phenomenon was concentration dependent. The expression of VEGFR2 protein was down-regulated by recombinant human Sema3A. Conclusion The expression of Sema3A was decreased in gastric cancer tissues, cell lines and patient serum, and negatively correlated with microvessel density. The recombinant human Sema3A could inhibit the angiogenesis of gastric cancer in vitro, which may be related to down-regulation of VEGFR2 protein expression.