Shh (Sonic Hedgehog) is a morphogen involved in gastric fundic gland differentiation in the adult. Shh expression is reduced in Helicobacter pylori-associated intestinal metaplastic change of the gastric epithelium and mice that lack Shh show intestinal transformation of the gastric mucosa. Similarly, in the stomach of Cdx2 (caudal-type homeobox 2)-transgenic mice, the gastric mucosa is replaced by intestinal metaplastic mucosa. The aim of the present study was to use Cdx2-transgenic mice to investigate: (i) Shh expression in the intestinal metaplastic mucosa of the Cdx2-transgenic mouse stomach; and (ii) the relationship between Shh and Cdx2. We determined that Shh mRNA levels were dramatically reduced in the intestinal metaplastic mucosa of the Cdx2-transgenic mouse stomach compared with the normal (wild-type) mouse stomach. This was not due to hypermethylation of the Shh promoter, but instead we showed that Cdx2 directly bound to the TATA box region of the Shh promoter. Cdx2 also down-regulated transcription of the Shh gene in the human gastric carcinoma cell lines AGS, MKN45 and MKN74. In conclusion, Cdx2 reduced Shh expression by binding to the unmethylated Shh promoter in the intestinal metaplastic mucosa of Cdx2-transgenic mouse stomach.

Cdx1 and Cdx2, which are transcription factors regulating normal intestinal development, have been studied as potential key molecules in the pathogenesis of the precancerous intestinal metaplasia of the human stomach. However, the regulation of Cdx1 expression in the intestinal metaplasia is poorly understood. Cdx2‐expressing gastric mucosa of Cdx2‐transgenic mouse stomach was replaced by intestinal metaplastic mucosa. The aim of this study was to investigate the following: (a) Cdx1 expression in the intestinal metaplastic mucosa of the Cdx2‐transgenic mouse stomach; and (b) the relationship between Cdx1 and Cdx2. A mouse model of intestinal metaplasia, the Cdx2‐transgenic mouse, was used to investigate Cdx1 gene expression by RT‐PCR. DNA methylation profile analysis was performed by bisulfite sequencing, and the interaction of Cdx2 with the Cdx1 promoter was examined by chromatin immunoprecipitation assay, electrophoretic mobility shift assay, and luciferase reporter assays. Cdx2 mRNA was expressed in the Cdx2‐transgenic mouse stomach. However, endogenous Cdx2 mRNA was not expressed in the intestinal metaplasia of the Cdx2‐transgenic mouse stomach. On the other hand, endogenous Cdx1 mRNA and protein were expressed in the intestinal metaplasia of the Cdx2‐transgenic mouse stomach. The Cdx1 promoter was unmethylated in the intestinal metaplasia of the Cdx2‐transgenic mouse stomach. Chromatin immunoprecipitation assay and electrophoretic mobility shift assay showed that Cdx2 was bound to the Cdx1 promoter region in the intestinal metaplasia and the normal intestine. Cdx2 upregulated and siRNA‐Cdx2 downregulated the transcriptional activity of the Cdx1 gene in the human gastric carcinoma cell lines AGS, MKN45, and MKN74. In conclusion, transgenic Cdx2 induced endogenous Cdx1 through the binding of Cdx2 to the unmethylated Cdx1 promoter region in the intestinal metaplasia of the Cdx2‐transgenic mouse stomach.

Helicobacter pylori (H. pylori) stimulates secretion of monocyte chemoattractant protein 1 (MCP-1) from gastric mucosa. Monocyte chemoattractant protein-1 (MCP-1) expression and macrophage infiltration are recognized in human gastric carcinoma. We have previously generated Cdx2-transgenic mice as model mice for intestinal metaplasia. Both chronic H. pylori-associated gastritis and Cdx2-transgenic mouse stomach develop intestinal metaplasia and finally gastric carcinoma. In this study we have directed our attention to MCP-1 expression in the intestinal metaplastic mucosa and the gastric carcinoma of Cdx2-transgenic mouse stomach. Quantitative real-time PCR was performed to determine MCP-1 and transforming growth factor-b1 (TGF-b1) mRNA expression levels and single-or double-label immunohistochemistry was used to evaluate the localization of MCP-1, TGF-b type I receptor, and a-smooth muscle actin (aSMA). We determined that MCP-1 mRNA dramatically increased in the intestinal metaplastic mucosa and the gastric carcinoma of Cdx2-transgenic mouse stomach, compared with normal mouse stomach. Both MCP-1 and TGF-b type I receptor were co-expressed in the aSMA-positive myofibroblasts of intestinal metaplastic mucosa and gastric carcinoma. Exogenous application of TGF-b1 increased MCP-1 mRNA expression levels in the intestinal metaplastic tissue. Furthermore, TGF-b1 was overexpressed and macrophage was strongly infiltrated in the gastric carcinoma. In conclusion, MCP-1 expression, which was stimulated by TGF-b1, was recognized in the TGF-b type I receptor-expressing myofibroblasts of the intestinal metaplastic mucosa and the gastric carcinoma of Cdx2-transgenic mouse stomach. The present results suggest that intestinal metaplasia and gastric carcinoma themselves induce MCP-1 expression independently of H. pylori infection. (Cancer Sci 2010; 101: 1783-1789 V arious inflammatory mediators have been detected in higher concentrations in Helicobacter pylori (H. pylori)-infected gastric mucosa. Furthermore, gastric carcinoma secretes a variety of chemoattractants that attract macrophages and cause them to accumulate in the tumor tissue, wherein the macrophage becomes a tumor-associated macrophage (TAM). Chemoattractant cytokines (chemokines) form a superfamily of closely related secreted proteins that specialize in mobilizing leukocytes to areas of infected tissues.(1) Monocyte chemoattractant protein-1 (MCP-1) is a CC chemokine that has functional action on monocytes and lymphocytes and plays a major role in regulating monocytes and lymphocytes migrating into tissues. Patients infected with H. pylori have significantly greater mRNA expression of MCP-1 in the gastric mucosa than patients without H. pylori infection.(2) Chronic H. pylori-associated gastritis is accompanied by monocyte and lymphocyte infiltration, in addition to neutrophil infiltration. (3,4) Significant correlation is seen between MCP-1 mRNA expression and mononuclear cell infiltration. Helicobacter pylori (H. pylori) infection of gastric epithelial cell lines al...

No abstract

Background/AimsSOX9 is a marker for stem cells in the intestine, and overexpression of SOX9 is found in gastric and colon cancer; however, the expression of SOX9 in nonampullary duodenal adenoma and adenocarcinoma has not yet been evaluated. This study aimed to investigate SOX9 expression in nonampullary duodenal adenoma and adenocarcinoma by immunohistochemistry.MethodsWe evaluated SOX9 expression in 43 clinical samples (nonampullary duodenal adenoma in 22 lesions and nonampullary duodenal adenocarcinoma in 21 lesions) resected under endoscopic mucosal resection or endoscopic submucosal dissection.ResultsSOX9 was expressed in part of the base of the normal duodenal mucosa surrounding adenomas and adenocarcinomas. In contrast, SOX9-positive cells were found in more than half of the crypts from the bottom part of the crypt in all of the 43 samples. Moreover, in 15 adenoma samples (68.2%) and 19 carcinoma samples (90.5%), SOX9 was expressed in more than three-quarters of the crypts from the bottom part of the crypt.ConclusionsSOX9 is overexpressed in nonampullary duodenal adenoma and adenocarcinoma in humans.