Increased expression of miR-146a, miR-10b, and miR-21 in cancer stem-like gastro-spheres.

BACKGROUND: Gastric cancer remains one of the leading causes of cancer-associated mortalities globally. Accumulating evidence support the presence of gastric cancer stem cells (CSCs) and their role in the pathogenesis and therapeutic challenges of gastric cancer. MicroRNAs (miRNAs) may be influenced by the cellular differentiative state and as critical regulators of the cellular fate in development and cancer, can modulate the behavior of CSCs too. Here, we aimed to investigate the expression relevance of three prognostic miRNAs (miR-21, miR-10b, and miR-146a) in CSCs of AGS and MKN-45 gastric cancer cell lines. METHODS: Serial sphere-forming assay in serum-free culture medium was used to enrich the cellular population with stem-like properties. Gastro-spheres were characterized by evaluating the stemness gene expression, clonogenicity, and resistance to docetaxel and cisplatin in comparison with their parental cells. The expression level of miRNAs in gastro-spheres and their parental cells was measured using quantitative reverse transcription polymerase chain reaction. RESULTS: Gastro-spheres from both cell lines exhibit stem-like properties: upregulated stemness associated genes (P < 0.05), more colonogenicity and more resistance to docetaxel (P < 0.05). MKN-45 gastro-spheres exhibited upregulated expression of miR-21 (1.8-folds), miR-10b (1.34-folds) and miR-146a (4.8-folds; P < 0.05) compared with the parental cells. AGS-derived gastro-spheres showed upregulation of miR-21 (4.7-folds; P < 0.01), miR-10b (15.2-folds; P < 0.001) and miR-146a (39.3-folds; P < 0.05). CONCLUSION: Our data exhibited upregulation of miR-21, miR-10b, and miR-146a in the stem-like gastro-spheres; however; their function in gastric CSCs remains to be verified by further experiments.

Epidemiology of Shigella-associated diarrhea in Gorgan, north of Iran.

OBJECTIVE: Shigella is an important etiological agent for diarrhea and especially dysentery. Shigellosis is an intestinal infection that is a major public health problem in many developing countries. The aim of this study was to evaluate the prevalence of Shigella and its various species in diarrheal samples in Gorgan located in the north of Iran. MATERIALS AND METHODS: Between January-December 2005, the epidemiology of Shigella- associated diarrhea was studied among 634 patients in Gorgan. The diarrheal samples accompanied with a questionnaire, which contained the demographic and main symptoms of the patients, were transported to the laboratory and inoculated in different culture media. Colonies suspected to be of Shigella were detected using differential biochemical tests and subsequently, the serotype of Shigella was defined using antisera. RESULTS: Shigella was isolated from 56/634 diarrheal samples) (8.8%) of which S. sonnei was the predominant species (55%). Occurrence of Shigella was highest in the 2-5 years' age group (70.9%) and highest in summer (73.2%) with the most frequent clinical manifestation being abdominal pain (67.8%). The prevalence of Shigella in males and females was 8 and 9.8% respectively, but this difference was not statistically significant. CONCLUSION: It has been shown that Shigella sonnei is the most common Shigella serogroup among 2-5 year-old children in Gorgan. It is therefore suggested that hygienic training be given to childcare attendants and the children themselves.