Naotaka Ogasawara

Expression of Cdx2 and the phenotype of advanced gastric cancers: relationship with prognosis

PurposeThe clinicopathologic significance of the phenotype and Cdx2 expression has hitherto remained unclear in gastric cancers. In the present study, we therefore examined the correlation between prognosis, phenotype, and Cdx2 expression in advanced cases.MethodsWe evaluated 177 advanced gastric carcinomas histologically and phenotypically. The expression of Cdx2 was also assessed by immunohistochemistry.ResultsThe lesions were phenotypically divided into 32 gastric (G type), 36 gastric and intestinal mixed (GI type), 53 intestinal (I type), and 56 null (N type) types, independent of the histological classification. Cdx2 nuclear staining demonstrated a close relation to intestinal phenotypic expression, not with the histological classification. Kaplan-Meier analysis of Cdx2 expression and the phenotype showed that the Cdx2 positive groups had a significantly better outcome than the negative ones (P =0.0013), and the patients with GI type cancers had significant better survival than those with N type (P =0.0052).ConclusionsOur results suggest that Cdx2 is a useful prognostic marker. In addition, advanced gastric cancers with both intestinal and gastric phenotypic expression have a relatively good prognosis. Combined evaluation of gastric and intestinal epithelial cell markers, including Cdx2, is clinically useful to predict outcome in patients with advanced neoplasm of the stomach.

Changes in 12-Year First-Line Eradication Rate of Helicobacter pylori Based on Triple Therapy with Proton Pump Inhibitor, Amoxicillin and Clarithromycin

A triple therapy based on a proton pump inhibitor (PPI), amoxicillin (AMPC), and clarithromycin (CAM) is recommended as a first-line therapy for Helicobacter pylori (H. pylori) eradication and is widely used in Japan. However, a decline in eradication rate associated with an increase in prevalence of CAM resistance is viewed as a problem. We investigated CAM resistance and eradication rates over time retrospectively in 750 patients who had undergone the triple therapy as first-line eradication therapy at Nagoya City University Hospital from 1995 to 2008, divided into four terms (Term 1: 1997–2000, Term 2: 2001–2003, Term 3: 2004–2006, Term 4: 2007–2008). Primary resistance to CAM rose significantly over time from 8.7% to 23.5%, 26.7% and 34.5% while the eradication rate decreased significantly from 90.6% to 80.2%, 76.0% and 74.8%. Based on the PPI type, significant declines in eradication rates were observed with omeprazole or lansoprazole, but not with rabeprazole. A decrease in the H. pylori eradication rate after triple therapy using a PPI + AMPC + CAM has been acknowledged, and an increase in CAM resistance is considered to be a factor. From now on, a first-line eradication regimen that results in a higher eradication rate ought to be investigated.

G protein-coupled receptor 43 moderates gut inflammation through cytokine regulation from mononuclear cells.

Background:Short-chain fatty acids (SCFAs), which are produced by the fermentation of dietary fiber by intestinal microbiota, may positively influence immune responses and protect against gut inflammation. SCFAs bind to G protein-coupled receptor 43 (GPR43). Here, we show that SCFA–GPR43 interactions profoundly affect the gut inflammatory response. Methods:Colitis was induced by adding dextran sulfate sodium to the drinking water of GPR43 knockout (−/−) and wild-type mice. Results:Dextran sulfate sodium–treated GPR43−/− mice exhibited weight loss, increased disease activity index (a combined measure of weight loss, rectal bleeding, and stool consistency), decreased hematocrit, and colon shortening, resulting in significantly worse colonic inflammation than in wild-type mice. Tumor necrosis factor alpha and interleukin 17 protein levels in the colonic mucosa of GPR43−/− mice were significantly higher than in wild-type mice. Treatment of wild-type mice with 150 mM acetate in their drinking water markedly improved these disease indices, with an increase in colon length and decrease in the disease activity index; however, it had no effect on GPR43−/− mice. Mononuclear cell production of tumor necrosis factor alpha after lipopolysaccharide stimulation was suppressed by acetate. This effect was inhibited by anti-GPR43 antibody. Conclusions:SCFA–GPR43 interactions modulate colitis by regulating inflammatory cytokine production in mononuclear cells.

Advantages of endoscopic submucosal dissection over conventional endoscopic mucosal resection

Background:  Endoscopic mucosal resection is an established method for treating intramucosal gastric neoplasms. Conventional endoscopic mucosal resection has predominantly been performed using strip biopsy, but local recurrence sometimes occurs due to such piecemeal resection. Endoscopic submucosal dissection has recently been performed in Japan using new devices such as an insulation‐tip diathermic knife. The efficacy and problems associated with endoscopic submucosal dissection were evaluated by comparison with conventional endoscopic mucosal resection.

Immunohistochemically detectable Cdx2 is present in intestinal phenotypic elements in early gastric cancers of both differentiated and undifferentiated types, with no correlation to non-neoplastic surrounding mucosa

It has previously been reported that Cdx2 is the useful prognostic and intestinal phenotypic marker in advanced gastric cancers (GC). In this study, Cdx2 expression and phenotype in early GC and non‐neoplastic surrounding mucosa were examined. A total of 130 early GC (70 intramucosal and 60 submucosally invasive cancers) histologically and phenotypically were evaluated. The expression of Cdx2 was assessed by immunohistochemistry. The lesions were phenotypically divided into 44 gastric (G), 42 gastric and intestinal mixed (GI), 30 intestinal (I), and 14 null (N) types, independent of the histological classification. Most of the early GC were Cdx2‐positive, nuclear staining being strongly associated with intestinal phenotypic expression. Early differentiated cancers tended to feature both Cdx2 and intestinal phenotypic expression, while their undifferentiated counterparts were more likely to demonstrate only gastric phenotypic expression (P < 0.05). The phenotypes of six intramucosal microcarcinomas did not correlate with those of adjacent normal glands. These data suggest that Cdx2 is expressed in the very early stage of gastric carcinogenesis in association with the shift from gastric to intestinal phenotypic expression. This appears to occur in differentiated cancers at an earlier stage than in undifferentiated ones, and may be linked to suppression of expansion of malignant cells.

Mutations and nuclear accumulation of β-catenin correlate with intestinal phenotypic expression in human gastric cancer

Aims:  Abnormal localization of β‐catenin is frequently observed in human gastric cancers. The aim of the present study was to evaluate relationships among gastrointestinal differentiation phenotypes, β‐catenin localization and mutations of Wnt signalling genes.

Impaired gastric motility and its relationship to reflux symptoms in patients with nonerosive gastroesophageal reflux disease

BackgroundMore than half of patients with refluxrelated symptoms have no endoscopic evidence of mucosal breaks. These patients are considered to have nonerosive gastroesophageal reflux disease (NERD). The pathogenesis of NERD may be multifactorial, but the role played by gastric motility in symptom generation in patients with NERD has not been examined. In this study, we elucidate gastric motility in patients with NERD and the efficacy of a prokinetic agent in the treatment of NERD.MethodsGastric motility was evaluated with electrogastrography (EGG) and by measurement of gastric emptying using the acetaminophen method in 26 patients with NERD and in 11 matched healthy controls. NERD patients were treated with a prokinetic agent (mosapride 15 mg, orally three times daily) for a period of 4 weeks, after which gastric motility was measured again.ResultsCompared with the healthy controls, the NERD patients showed a significantly lower percentage of normogastria, a lower power ratio in EGG, and delayed gastric emptying. Ten patients had normal gastric motor function (group A), and 16 showed abnormalities of either gastric myoelectrical activity or gastric emptying (group B). After treatment with mosapride, gastric motility improved significantly in both groups of patients compared with pretreatment values. The subjective assessment by the patient after the treatment was improved in 20.0% of group A versus 62.5% of group B patients (P < 0.05).ConclusionsGastric hypomotility appears to be an important factor in reflux symptom generation in some NERD patients.

Suppression of proHB-EGF Carboxy-Terminal Fragment Nuclear Translocation: A New Molecular Target Therapy for Gastric Cancer

Purpose: Inactivation of epidermal growth factor (EGF) receptor (EGFR) represents a promising strategy for the development of selective therapies against epithelial cancers and has been extensively studied as a molecular target for cancer therapy. However, little attention has been paid to remnant cell-associated domains created by cleavage of EGFR ligands. The present study focused on recent findings that cleavage of membrane-anchored heparin-binding EGF-like growth factor (proHB-EGF), an EGFR ligand, induces translocation of the carboxyl-terminal fragment (CTF) of HB-EGF from the plasma membrane to the nucleus and regulates cell cycle. Experimental Design: Two gastric cancer cell lines, MKN28 and NUGC4, were used. KB-R7785, an inhibitor of proHB-EGF shedding, was used to suppress HB-EGF-CTF nuclear translocation with cetuximab, which inhibits EGFR phosphorylation. Cell growth was analyzed using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt assay, apoptosis was evaluated by assay of caspase-3 and caspase-7, and cell cycle was investigated by flow cytometry. Results: Immunofluorescence study confirmed that KB-R7785 inhibited HB-EGF-CTF nuclear translocation under conditions of proHB-EGF shedding induction by 12-O-tetradecanoylphorbol-13-acetate in gastric cancer cells. KB-R7785 inhibited cell growth in a dose-dependent manner and high-dose KB-R7785 induced apoptosis. Moreover, KB-R7785 induced cell cycle arrest and increased sub-G1 DNA content. KB-R7785 suppressed cyclin A and c-Myc expression. All effects of KB-R7785 were reinforced by combination with cetuximab. Conclusions: These results suggest that both inhibition of EGFR phosphorylation and inhibition of HB-EGF-CTF nuclear translocation play crucial roles in inhibitory regulation of cancer cell growth. Suppression of HB-EGF-CTF nuclear translocation might offer a new strategy for treating gastric cancer.

β-Catenin mutations and nuclear accumulation during progression of rat stomach adenocarcinomas

Aberrant Wnt/β‐catenin signaling caused by mutations in exon 3 of the β‐catenin gene has been identified in a number of human malignancies, including stomach cancer. However, studies of mutation frequency have yielded conflicting results, and timing during progression remains largely unknown. In this study, we utilized an animal model to address this question. A total of 20 ACI male rats were treated with N‐methyl‐N′‐nitro‐N‐nitrosoguanidine (MNNG) in the drinking water and 22 induced differentiated adenocarcinomas were histopathologically and immunohistochemically evaluated for β‐catenin localization. Fourteen tumors (63.6%) that showed homogeneous low‐grade morphology, preserving cell polarity, were found to harbor β‐catenin protein on the cell membranes (M). Eight tumors exhibited regions of high‐grade morphology among areas with low‐grade morphology, and they were characterized by denser cell growth and loss of cell polarity. Among these 8 tumors, 4 (18.2%) showed cytoplasmic localization (C) of β‐catenin in small regions. The remaining 4 tumors (18.2%) contained more dysplastic regions that displayed nuclear (N) β‐catenin staining. Analysis of DNA obtained by microdissection demonstrated that all of 4 regions with C staining and 20 with M staining, as well as 17 samples of surrounding normal mucosa (S) had wild‐type β‐catenin. In contrast all of 3 regions with N staining featured mutations (3 of 3=100%; N vs. C, P<0.05; N vs. M and N vs. S, P<0.001, Fishers exact test) in exon 3, at glycine 34, threonine 41, and serine 45, which affected phosphorylation sites. In conclusion, β‐catenin mutations appear to be associated with the late progression stage of adenocarcinoma development in rat stomach carcinogenesis, in contrast to the case of colorectal cancers, in which mutations appear to occur in the early stages.

Blockage of angiotensin II type 1 receptor regulates TNF-α-induced MAdCAM-1 expression via inhibition of NF-κB translocation to the nucleus and ameliorates colitis

Mucosal vascular addressin cell adhesion molecule 1 (MAdCAM-1) is an important target in the treatment of inflammatory bowel disease (IBD). Recently, treatment of IBD with an antibody to alpha4beta7-integrin, a ligand for MAdCAM-1, has been an intense focus of research. Our aim was to clarify the mechanism by which MAdCAM-1 is regulated via angiotensin II type 1 receptor (AT1R), and to verify if AT1R might be a novel target for IBD treatment. The role of AT1R in the expression of MAdCAM-1 in SVEC (a murine high endothelial venule cell) and MJC-1 (a mouse colonic endothelial cell) was examined following cytokine stimulation. We further evaluated the effect of AT1R on the pathogenesis of immune-mediated colitis using AT1R-deficient (AT1R-/-) mice and a selective AT1R blocker. AT1R blocker significantly suppressed MAdCAM-1 expression induced by TNF-alpha, but did not inhibit phosphorylation of p38 MAPK or of IkappaB that modulate MAdCAM-1 expression. However, NF-kappaB translocation into the nucleus was inhibited by these treatments. In a murine colitis model induced by dextran sulfate sodium, the degree of colitis, judged by body weight loss, histological damage, and the disease activity index, was much milder in AT1R-/- than in wild-type mice. The expression of MAdCAM-1 was also significantly lower in AT1R-/- than in wild-type mice. These results suggest that AT1R regulates the expression of MAdCAM-1 under colonic inflammatory conditions through regulation of the translocation of NF-kappaB into the nucleus. Furthermore, inhibition of AT1R ameliorates colitis in a mouse colitis model. Therefore, AT1R might be one of new therapeutic target of IBD via regulation of MAdCAM-1.