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Human Gastric Cancer Cell Line (human + gastric_cancer_cell_line)
Selected AbstractsMechanism of Action of Low Recurrence of Gastritis Caused by Helicobacter pylori with the Type II Urease B GeneHELICOBACTER, Issue 2 2004Md. Badruzzaman ABSTRACT Background., Low recurrence of gastritis is seen in patients infected with Helicobacter pylori carrying the type II urease B gene, compared with H. pylori carrying types I and III. The underlying mechanism has been studied in terms of the urease activity and interleukin (IL)-8 production capacity of different strains of H. pylori. Materials and Methods., Forty-five patients infected with different strains of H. pylori (type I; 15, type II; 15 and type III; 15) were enrolled in the study. H. pylori was isolated from gastric mucosa and cultured in the presence of urea at pH 5.5 to evaluate urease activity. The capacity of different strains of H. pylori to induce IL-8 mRNA and IL-8 from a human gastric cancer cell line and human peripheral blood mononuclear cells was evaluated. Results., The urease activity of type II H. pylori[523 ± 228 µg of ammonia/dl/108 colony-forming units (CFU)/ml] was significantly lower than that of type I (1355 ± 1369 µg of ammonia/dl/108 CFU/ml) and type III (1442 ± 2229 µg of ammonia/dl/108 CFU/ml) (p < .05). Gastric cancer cells cocultured with type II H. pylori produced lower levels of IL-8 mRNA compared with type I and type III H. pylori. The levels of IL-8 were also significantly lower in cultures induced by type II H. pylori compared with those induced by type I and type III H. pylori. Peripheral blood mononuclear cells also produced lower levels of IL-8 when cocultured with type II compared with type I H. pylori. Conclusions., These results indicate that both the lower level of urease activity and the low IL-8-inducing capacity of type II H. pylori might underlie the lower recurrence rate of gastritis caused by type II H. pylori. [source] Bmi-1 is critical for the proliferation and invasiveness of gastric carcinoma cellsJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 3 2010Wei Li Abstract Background and Aim:, Bmi-1 is a transcriptional repressor belonging to the Polycomb group and is associated with the cell proliferation and carcinogenesis of a variety of human cancers. The level of Bmi-1 expression correlates with the aggressiveness of many cancers, and is considered an important marker for cancer diagnosis. However, its role in gastric carcinoma is unknown. Methods:, We used lentiviral mediated interfering short hairpin RNA to knockdown Bmi-1 expression in gastric carcinoma human gastric cancer cell line (AGS cells), then tested the cell proliferation by MTT assay, rate of colony formation by colony formation assay, cell cycle distribution by fluorescence-activated cell sorting and cell invasiveness by cell invasion assay. To analyze the expression and localization of Bmi-1 in gastric tumor tissues, we further performed the immunohistochemistry analysis on a gastric cancer tissue array. Results:, We found that knocking down Bmi-1 led to slower cell growth, lesser cell invasiveness, decelerated colony formation, and altered cell cycle progression. In addition, a positive relationship between nuclear expression of Bmi-1 and gastric cancer was observed, suggesting that nucleus localization of Bmi-1 in the cells may be a novel marker of gastric cancer. Conclusions:, Our study highlights critical roles for Bmi-1 in gastric cancer, and suggests that Bmi-1 nuclear localization could be an important marker for the diagnosis of gastric cancer. [source] Mammalian target of rapamycin is activated in human gastric cancer and serves as a target for therapy in an experimental modelINTERNATIONAL JOURNAL OF CANCER, Issue 8 2007Sven A. Lang Abstract The mammalian target of rapamycin (mTOR) has become an interesting target for cancer therapy through its influence on oncogenic signals, which involve phosphatidylinositol-3-kinase and hypoxia-inducible factor-1, (HIF-1,). Since mTOR is an upstream regulator of HIF-1,, a key mediator of gastric cancer growth and angiogenesis, we investigated mTOR activation in human gastric adenocarcinoma specimens and determined whether rapamycin could inhibit gastric cancer growth in mice. Expression of phospho-mTOR was assessed by immunohistochemical analyses of human tissues. For in vitro studies, human gastric cancer cell lines were used to determine S6K1, 4E-BP-1 and HIF-1, activation and cancer cell motility upon rapamycin treatment. Effects of rapamycin on tumor growth and angiogenesis in vivo were assessed in both a subcutaneous tumor model and in an experimental model with orthotopically grown tumors. Mice received either rapamycin (0.5 mg/kg/day or 1.5 mg/kg/day) or diluent per intra-peritoneal injections. In addition, antiangiogenic effects were monitored in vivo using a dorsal-skin-fold chamber model. Immunohistochemical analyses showed strong expression of phospho-mTOR in 60% of intestinal- and 64% of diffuse-type human gastric adenocarcinomas. In vitro, rapamycin-treatment effectively blocked S6K1, 4E-BP-1 and HIF-1, activation, and significantly impaired tumor cell migration. In vivo, rapamycin-treatment led to significant inhibition of subcutaneous tumor growth, decreased CD31-positive vessel area and reduced tumor cell proliferation. Similar significant results were obtained in an orthotopic model of gastric cancer. In the dorsal-skin-fold chamber model, rapamycin-treatment significantly inhibited tumor vascularization in vivo. In conclusion, mTOR is frequently activated in human gastric cancer and represents a promising new molecular target for therapy. © 2007 Wiley-Liss, Inc. [source] Expression and subcellular location of COX-2 in human gastric cancer cellsJOURNAL OF DIGESTIVE DISEASES, Issue 2 2001Li Ling OBJECTIVE: To detect the expression of cyclooxygenase (COX) in human gastric cancer cell lines and determine the subcellular location of its isoforms. METHODS: Immunohistochemistry, reverse transcription,polymerase chain reaction (RT-PCR), and laser scanning confocal microscopy (LSCM) were used to investigate the expression and distribution of COX. RESULTS: Positive staining for COX-2 and COX-1 protein was seen in human gastric cancer cell lines MKN45, SGC7901 and AGS. However, COX-2 staining was absent and COX-1 staining was weak in the MGC803 cell line, although COX-2 mRNA was present in all four cell lines. When compared with COX-1, COX-2 was more strongly expressed at both protein and mRNA levels in the gastric cancer cell lines, which was confirmed by double labeling and LSCM. A quantitative analysis of fluorescein intensity indicated that the pixel intensity peak of COX-2 had a gray scale value of 50,70, while COX-1 was only 10. The LSCM technique also revealed the presence of COX-2 in the cytoplasm and nuclear envelope and COX-1 in the cytoplasm only. CONCLUSIONS: In human gastric cancer cells, COX-2 is expressed at higher levels than COX-1 and the different distributions of the two isoforms suggest that their roles in cell function are distinct. [source] | ||||||||||