To develop an efficient animal model for colitis-related carcinogenesis, male Crj: CD-1 (ICR) mice were given a single intraperitoneal administration (10 mg/kg body weight) of a genotoxic colonic carcinogen, azoxymethane (AOM), and a 1-week oral exposure (2% in drinking water) to a non-genotoxic carcinogen, dextran sodium sulfate (DSS), under various protocols. At week 20, colonic neoplasms (adenocarcinomas, 100% incidence with 5.60 ± ± ± ±2.42 multiplicity; and adenomas, 38% incidence with 0.20 ± ± ± ±0.40 multiplicity) with dysplastic lesions developed in mice treated with AOM followed by DSS. Protocols in which AOM was given during or after DSS administration induced a few tubular adenomas or no tumors in the colon. Immunohistochemical investigation of such dysplasias and neoplasms revealed that all lesions were positive for β β β β-catenin, cyclooxygenase-2 and inducible nitric oxide synthase, but did not show p53 immunoreactivity. The results indicate that 1-week administration of 2% DSS after initiation with a low dose of AOM exerts a powerful tumor-promoting activity in colon carcinogenesis in male ICR mice, and may provide a novel mouse model for investigating colitis-related colon carcinogenesis and for identifying xenobiotics with modifying effects. (Cancer Sci 2003; 94: 965-973) n the developed world, colorectal cancer (CRC) is one of the commonest non-smoking related cancers. This malignancy is one of the most serious complications of inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), 1,2) and the risk of CRC increases with increasing extent and duration of the disease.Animal experiments are assumed to simulate or at least provide plausible pathophysiological mechanisms in various diseases including cancer and inflammatory disorders. For IBD and IBD-related CRC, several animal models have been reported. The most widely used is a mouse model with dextran sodium sulfate (DSS).3) There are a number of reports on modifying effects of xenobiotics on CRC-related colon carcinogenesis in this model 4,5) : folic acid, short chain fatty acid (butyrate), ursodeoxycholic acid, nonsteroidal anti-inflammatory drugs (NSAIDs)/cyclooxygenase (COX)-2 inhibitors, and 5-aminosalicylic acid (5-ASA) were found to inhibit the occurrence of UC-related CRC. However, this colitis model using DSS with or without carcinogen needs a long period or repeated administration of DSS to induce colitis and colitis-related CRC, and the incidence and/or multiplicity of induced tumors are relatively low.6) Many studies have suggested that chronic or repeated mucosal inflammation may result in carcinogenesis through mechanisms such as induction of genetic mutations, increased cryptal cell proliferation, changes in crypt cell metabolism, changes in bile acid enterohepatic circulation, and alterations in bacteria flora. 7,8) These ideas are consistent with the hypothesis that chronic inflammation could be associated with epithelial malignant neoplasia in the large bowel. 8) We recently reported c...

Recent studies suggest that metformin, which is commonly used as an oral anti-hyperglycemic agent of the biguanide family, may reduce cancer risk and improve prognosis, but the mechanisms by which metformin affects various cancers, including gastric cancer, remains unknown. The goal of the present study was to evaluate the effects of metformin on human gastric cancer cell proliferation in vitro and in vivo and to study microRNAs (miRNA) associated with antitumor effect of metformin. We used MKN1, MKN45, and MKN74 human gastric cancer cell lines to study the effects of metformin on human gastric cancer cells. Athymic nude mice bearing xenograft tumors were treated with or without metformin. Tumor growth was recorded after 4 weeks, and the expression of cell-cycle-related proteins was determined. In addition, we used miRNA array tips to explore the differences among miRNAs in MKN74 cells bearing xenograft tumors treated with or without metformin in vitro and in vivo. Metformin inhibited the proliferation of MKN1, MKN45, and MKN74 in vitro. Metformin blocked the cell cycle in G 0 -G 1 in vitro and in vivo. This blockade was accompanied by a strong decrease of G 1 cyclins, especially in cyclin D1, cyclin-dependent kinase (Cdk) 4, Cdk6 and by a decrease in retinoblastoma protein (Rb) phosphorylation. In addition, metformin reduced the phosphorylation of epidermal growth factor receptor and insulin-like growth factor-1 receptor in vitro and in vivo. The miRNA expression was markedly altered with the treatment of metformin in vitro and in vivo. Various miRNAs altered by metformin also may contribute to tumor growth in vitro and in vivo. Mol Cancer Ther; 11(3); 549-60. Ó2012 AACR.

Rescue therapy for gastrointestinal (GI) refractory bleeding, perforation, and fistula has traditionally required surgical interventions owing to the limited performance of conventional endoscopic instruments and techniques. An innovative clipping system, the over-the-scope clip (OTSC), may play an important role in rescue therapy. This innovative device is proposed as the final option in endoscopic treatment. The device presents several advantages including having a powerful sewing force for closure of GI defects using a simple mechanism and also having an innovative feature, whereby a large defect and fistula can be sealed using accessory forceps. Consequently, it is able to provide outstanding clinical effects for rescue therapy. This review clarifies the current status and limitations of OTSC according to different indications of GI refractory disease, including refractory bleeding, perforation, fistula, and anastomotic dehiscence. An extensive literature search identified studies reported 10 or more cases in which the OTSC system was applied. A total of 1517 cases described in 30 articles between 2010 and 2018 were retrieved. The clinical success rates and complications were calculated overall and for each indication. The average clinical success rate was 78% (n = 1517) overall, 85% for bleeding (n = 559), 85% (n = 351) for perforation, 52% (n = 388) for fistula, 66% (n = 97) for anastomotic dehiscence, and 95% (n = 122) for other conditions, respectively. The overall and severe OTSC-associated complications were 1.7% (n = 23) and 0.59% (n = 9), respectively. This review concludes that the OTSC system may serve as a safe and productive device for GI refractory diseases, albeit with limited success for fistula.

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