| MicroRNAs (miRNAs) are an important class of regulative smallnon-coding RNAs in eukaryotic cells, which are about22nt, can regulatevarious gene expression at post transcriptional level in multicellular througheither perfect or imperfect binding to3’-untranslated regions (3’-UTR) oftarget mRNA and result in translation repression or degradation of the targetmRNA. In recent years, studies of miRNAs have been found in growingnumber and clarify further in function. Existing evidence state clearly thatmiRNAs can target about60%of total genes and each of miRNA caninhibit hundreds of target genes. While the disturbance of miRNAsexpression will lead to their target genes up-regulation or down-regulation.Also miRNAs can function significantly as potential oncogenes or tumorsuppressor genes during the initiation and progression of cancer. Therefore,studies of miRNAs lay a solid foundation for clinical diagnosis andtreatment of cancer.Gastric carcinoma is malignant tumor originated from gastric mucosalepithelium and glandular epithelium, which is one of the most common cancers of digestive system and high incidence of malignant tumor in Asia.In our country, gastric carcinoma is ranking first place in all types ofcancers and the incidence rate is increasing with the age. But the etiologyof gastric carcinoma is not very clear, which may have to do with regionalenvironment, eating habits, Helicobacter pylori infection, precancerouslesions, heredity and gene. Currently, with the width of researches onmiRNAs, a number of which are found to be close associated with gastriccarcinoma.In this study, real-time PCR analysis was used to identify theexpression of miR-125b in40gastric cancer tissues and pairedcancer-adjacent tissues. The synthesized miR-125b mimic was transfectedinto cultured gastric cancer cell lines HGC-27and MGC-803. After48h,the expression of transfection efficiency was measured by real-time PCR.After the accomplishment of ectopic expression was confirmed, the cellproliferation and apoptosis were detected by CCK-8and flow cytometryrespectively. The results show that miR-125b was significantlyup-regulated in gastric cancer tissues compared with cancer-adjacentcontrols（P<0.01）. Ectopic expression of miR-125b in HGC-27andMGC-803cells increased cell proliferation, whereas decreased cellapoptosis. Cells transfected for72h, HGC-27（scramble：1.632±0.09，mimic：2.473±0.08），MGC-803（scramble：1.603±0.05，mimic：2.554±0.07）. From the above, miR-125b may act as an oncogene in gastric carcinoma via interfering with cell proliferation and apoptosis, which laythe groundwork to discover the possible target genes of miR-125bsubsequently and then dig into the function and mechanisms of miR-125b. |
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