E-cadherin Gene Demethylation Induced By5-aza-2'-Deoxycytidine On The Influence Of Gastric Cancer Cell Proliferation And Invasion Ability

Background：Cadherin encoded by E-cadherin gene between the epithelial cells, which mediatehomogeneity adhesion and maintain the tissue structural integrity. E-cadherin is animportant tumor suppressor gene, it can inhibit the proliferation of tumor cells and theinvasion and metastasis of cast-off tumor cells.E-Cad gene inactivation result inreduction of the expression of the protein and prompte the development of tumors. Itis a very important reason of recurrent and death in patients after operation that theinvasion and metastasis of gastric carcinoma. The present study found that except forthe mechanism of gene mutations and loss of heterozygosity, CpG island methylation ofthe E-cad gene promoter is also a more important mechanism of the gene inactivation,.However, it's different from the former two mechanisms, gene promoter methylationdoes not involve DNA sequence change, this kind of change is reversible.The closed E-cadherin gene could obtain expression again by eliminating the gene promotermethylation, which can suppress tumor invasion, metastasis growth, to achieve thepurpose of treatment of tumor, therefore it may be the new target for tumor therapy.Objective：we aimed to observe E-cardherin gene promoter methylation state whetherreverse and re-expression,and to understand the change of invasion and metastasisof gastric carcinoma after demethylation, through E-cardherin gene of gastriccarcinoma demethylation with5-nitrogen miscellaneous-2'a nucleoside deoxidizationcell.we maybe provide basic research for demethylation treatment of cancer in thefuture.Methods：1. Purchase MKN-45cell of gastric carcinoma,and Recovery,freeze-preserving, change solution,digestion and passage, then collect cells,set aside.2. The experiment was separated into three groups: A:5-Aza-CdR treatmentgroup, B: DMSO+medium treatment group, C: blank control group. collecting thecells after processing training72hours.3. Detection the expression level of mRNA of E-cadherin gene deal with semi-quantitative pcr.4. testing the change of invasion of gastric carcinoma MKN-45cell that wasprocess by5-Aza-CdR.5. testing apoptosis of each cell by TUNEL6.Test5'-CpG island methylation levels of E-cadherin gene bymethylation-specific PCR(MSP)Results：1.The growth of gastric carcinoma MKN-45cells that process by5-Aza-CdRwas slow compared with the control group2.The E-cadherin gene mRNA of gastric carcinoma MKN-45cells was restoreand up-regulate even by semi-quantitative pcr,which demethylation by5-Aza-CdR.3.A part of E-cadherin gene of gastric carcinoma MKN-45cells wasmethylation,and E-cadherin gene can be induce to demethylation that in the state ofmethylation.4.The invasion of gastric carcinoma MKN-45cells that process by5-Aza-CdRwas drop,and the count of transmembrane cells was reduced compared to controlgroup.5.The number of apoptosis gastric carcinoma MKN-45cells was increased,andthe apoptosis index was higher than control groupConclusions：1.E-cadherin gene expression level related to DNA methylation in gastriccarcinoma MKN-45cells,and E-cadherin gene promoter abnormal methylation maybe the major reason of gene inactivation.2.5-Aza-CdR can induce the E-cad herin genes of less differentiation gastriccarcinoma MKN-45to methylation and make its expression enhanced. 3. The invasion dropping and the number of apoptotic cells increasing aftergastric carcinoma MKN-45cells was processed by5-Aza-CdR4. Demethylation treatment can reverse the methylation of gene promoter,andprovide a new management for gastric carcinoma.It's valuable to study further.