| Genomic imprinting is the epigenetic marking of a gene based on its parental origin, which results in monoallelic expression. Those genes with this feature are classified as imprinted genes. The roles that the abnormal changes in genetic imprinting and its supervising mechanism play in the pathogenesis of human genetic disorders, especially in the carcinogenesis is getting more and more attention. The PEG10 gene, which was found by Ono in 2001, are located on chromosome 7q21 as an oncogene. There are no correlated articles about the expression and effect of PEG10 in human gastric carcinoma nowadays. We investigated the expression of PEG10 in human gastric carcinoma, the relationship of PEG10 expression with Hp infection and the effect of PEG10 on cell growth and proliferation of gastric cancer cells in this article.Carcinoma of the stomach is the most common peptic cancer in the world. The incidence of gastric cancer is extremely high in Asia, especially in China. It is a major cause of cancer mortality in China. There is no sensitive biomarker of gastric carcinoma. Symptoms are minimal in early stage gastric cancer. In early gastric cancer, 5-year survival approaches 90% after operation; with advanced stage, survival is about 50%. Nowadays, the hot area of gastric carcinoma research is to investigate the pathogenesis and treatment in molecular level for early diagnosis and therapy. Objective To investigate the expression of PEG10 in human gastric carcinoma, and the relationship between PEG10 expression and helicobacter pylori infection; the effect of PEG10 on cell growth and proliferation of gastric cancer cells.Methods (1) PEG10 protein expression and the infection of Hp in 42 human gastric carcinoma, and the corresponding adjacent normal tissues and 6 normal gastric tissues was detected by immunohistochemistry and Warthin-Starry stain. (2)PEG10 mRNA expression in 20 human gastric carcinoma, the corresponding adjacent normal tissues and 6 normal gastric tissues was detected by RT-PCR. (3)The cDNA of PEG10 was cloned and the expression vectors of PEG10 (pcDNA3.1 and pEGFP) were constructed. (4) The expression of PEG10 in MKN45 cells and HepG2 cells was detected by RT-PCR. PEG10 gene was transfected into gastric cancer cell line MKN45 which had no endogenetic PEG10 expression. Cell growth ability was measured by MTT assay. The cell cycle of PEG10 transfected MKN45 cells was measured by flow cytometry; the apoptosis of PEG10 transfected MKN45 cells was detected by agarose electrophoresis and Annexin V fluos staining.Results (1)High PEG10 mRNA and PEG10 protein were detected in human gastric carcinoma which was significantly higher than those of the matched normal tissues . No expression of PEG10 in normal gastric tissues. The positive correlation between the expression of PEG10 and Hp infection was observed in gastric carcinoma tissues(P<0.01). (2)High PEG10 mRNA were detected in human gastric carcinoma which was significantly higher than those of the matched normal tissues (P<0.05). (3) The cDNA of PEG10 was cloned and the expression vectors of PEG10 (pcDNA3.1 and pEGFP) were constructed successfully. (4)There was no endogenetic PEG10 expression in gastric cancer cell line MKN45. The growth ability of PEG10 transfected MKN45 cells was increased. No influence on cell cycle was observed in PEG10 transfected MKN45 cells. There were typical ladder straps-DNA ladders in agarose electrophoresis and decreased apoptosis percentage was found in Annexin V staining.Conclusion PEG10 over expresses in human gastric carcinoma and correlated with Hp infection positively. The expression of PEG10 closely correlates with the tumor depth and surrounding organs invasion. The survival time of PEG10 positive group is shorter than PEG10 negative group. PEG10 increase the growth of gastric cells which has no influence on cell cycle. PEG10 inhibit the rate of cell apoptosis. |
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