Functional analysis on EphB and ephrin-B expressing in gastric mucosa and their expression behavior in gastric ulcer and cancer

用RT-PCR方法在成年啮齿动物胃粘膜中检测到EphB受体和ephrin-Bs。免疫染色显示互补的表达模式，EphB受体优先表达在胃单位的较深区域，肝配蛋白B优先表达在胃单位的较浅区域。在小鼠溃疡模型中，EphB 2表达在再生上皮中上调。原代胃上皮细胞中的EphB信号传导至少部分地通过RhoA活化促进细胞收缩和排斥。基于这些发现，作者提出，EphB阳性后代的胃干细胞迁移从峡部向底部的胃腺由于排斥信号所产生的接触ephrin-Bs，这是优先表达在更浅的区域的峡部和胃小凹。在大鼠胃癌模型中，EphB 2和肝配蛋白-B共定位于Ki 67阳性增殖细胞中，形成异常胃单位，并且胃癌细胞同时表达EphB受体和肝配蛋白-B配体。这些发现表明EphB受体和ephrin-B的同时表达指示胃癌细胞的特征。

Several EphB receptors and ephrin-Bs were detected in the gastric mucosa of the adult rodent stomach by RT-PCR amplification. Immunostaining showed complementary expression patterns, with EphB receptors preferentially expressed in the deeper regions and ephrin-Bs in the superficial regions of the gastric units. In a mouse ulcer model EphB2 expression was upregulated in the regenerating epithelium. EphB signaling in primary gastric epithelial cells promoted cell retraction and repulsion at least in part through RhoA activation. Based on these findings the author propose that the EphB-positive progeny of gastric stem cells migrates from the isthmus towards the bottom of the gastric glands due to repulsive signals arising from contact with ephrin-Bs, which are preferentially expressed in the more superficial regions of the isthmus and gastric pits. In a rat gastric cancer model EphB2 and ephrin-B were co-localized in Ki67-positive proliferative cells forming aberrant gastric units and gastric cancer cells were simultaneously expressed EphB receptors and ephrin-B ligands. These findings suggest that simultaneous expressions of both EphB receptors and ephrin-B indicates an characteristic of gastric cancer cells.