The mechanism of expression of gastric and intestinal character in epithelium of alimentary tract, and influence to prognosis of gastric cancer

本实验建立了小鼠腺胃上皮细胞系和小鼠食管、前胃、腺胃、空肠、结肠成纤维细胞系。通过免疫荧光研究，上皮细胞的紧密连接蛋白ZO-1和细胞角蛋白18呈阳性，仅在单层（非复层）上皮中表达，但不表达胃的特异性标记物，如MUC 5AC、MUC 6、胃蛋白酶原和H-K ATP酶。所有成纤维细胞均表达波形蛋白和α-SMA。当与成纤维细胞共培养时，上皮细胞形成粗的分支索，其经历进行性多灶性空化1周。这与MontesanoR等在肾细胞系（MDCK）中观察到的现象相同（1991 Cell 66：697-711），但是，即使与另一种类型的成纤维细胞共培养，上皮细胞的形成也没有不同。我们推测成纤维细胞在传代过程中失去了其特异性，Hox是机体发育分化所必需的同源盒基因，但Hox基因在胃肠道中的作用尚不清楚。本实验观察了HoxC 8、HoxA 5 mRNA在大鼠胃、小肠、结肠、胃黏膜中的表达。肠和结肠。RT-PCR分析显示Hox基因仅在小肠和结肠中表达，在胃中不表达。分离空肠上皮细胞和间充质细胞，分别检测Hox基因的表达，HoxC 8仅在空肠间充质细胞中表达。HoxC 8对空肠间充质的发育具有特异性和必需性。

We established epithelial cell line from mouse glanduar stomach, and some fibroblast cell lines from mouse esophagus, forstomach, glandular stomach, jejunum and colon. By the immunofluorescence study epithelial cells were positive for tight junction protein zo-1 and cytokeratin-18 that is expressed only within simple (nonstratified) epithelium, but were not expressed specific markers for the stomach, such as MUC5AC, MUC6, pepsinogen, and H-K ATPase. All fibroblasts expressed vimentin filaments and α-SMA.To examine epithelial-mesenchymal interactions, we developed 3-dimensional coculture system using type I collagen gel. The epithelial cells formed thick branching cords that underwent progressive multifocal cavitation for 1 week when they cocultured with fibroblasts. That was the same phenomena as MontesanoR etc. observed in the renal cell line (MDCK) (1991 Cell 66: 697-711) But, formation of epithelial cells were not different even when coculture with another types of fibroblast. We speculated that fibroblasts lost their specificity during passage of culture.Hox is the homeobox gene which is necessary for development and differentiation of body, but the role of Hox gene in GI tract has not been elucidate. We investigated expression of HoxC8, HoxA5 mRNA in stomach, small. intestine and colon. RT PCR analysis revealed that Hox gene expressed only in small intestine and colon but not in stomach. We separated epithelium from mesenchyme of jejunum and investigate the expression of Hox gene separately, HoxC8 is express only in the mesenchyme of jejunum. HoxC8 must be specific and necessary for development of mesenchyme of jejunum.