| Gastric cancer,the malignant tumor,has an extremely high incidence,whose mortality rate is second only to lung cancer in the world since twentieth Century.It is estimated that more than 70% of patients with gastric cancer are from developing countries up to 2016,which suggests that incidence of gastric cancer is associated with the air,pollution,water,population and other living environments.The five-year survival rate of patients with advanced gastric cancer remains low,so a further study of gastric cancer on cell invasion and growth pattern as well as the precise molecular mechanism of gastric cancer metastasis is necessary,screening a key target which is easily detected in the diagnosis of gastric cancer plays a significance role on prevention and treatment of gastric cancer.Transcription factor E2F3 plays a very important part on promoting the process of cancer metastasis.The precise construction of regulatory network of E2F3 can provide insight into the mechanism of the development of gastric cancer.The regulation of gene expression by micro RNA has an important role in the process of tumor metastasis,apoptosis and so on.In this study,differentially expressed genes and micro RNA in gastric cancer were screened by c DNA microarray.Combining with bioinformatics software,we also predicted the regulation of E2 F family-related micro RNA,transcription factors and target genes and constructed the transcriptional regulatory network of E2F3 family of gastric cancer which is related to the gene E2F3-centered,enrichment analysis with a large number of literature of regulatory were used to discover the relationships between genes E2F3 and micro RNA.Bioinformatics analysis showed that E2F3 is a direct target gene of miR-320 a and let-7d.Therefore,we hypothesized that miR-320 a and let-7d may regulate tumor progression and prognosis by targeting the expression of E2F3.Part one construction of TF-miRNA transcriptional regulatory network in gastric carcinomaBy using the gene difference analysis in 10 pairs of gastric cancer tissues and normal tissue expression and 10 pairs of micro RNA,we screened 809 up-regulated and 92 down-regulated differentially expressed genes,the expression of micro RNA 58 up-regulated and 8 down-regulated.A total of 32 differentially expressed genes were related to the regulation of E2 F family by TRED database,GO analysis and Pathway analysis was applied to analyze the main function of the differential expression genes.This study provides data information and theoretical for the detection of gastric cancer genes.Combined with the prediction of micro RNA database such as Targetscan,10 micro RNA conclude miR-320 a,miR-200,miR-150,miR-125a-5p,miR-92 a,miR-31,miR-30,miR-17,let-7d,let-7i were found have a relationship with E2F3.After a large number of literature enrichment analysis,we screened miR-320 a,let-7d is likely to affect the process of gastric cancer metastasis by regulating E2F3.Part two the study on the regulation of miR-320 a by E2F3 and let-7dWestern blot and qRT-PCR detection were used to detect the expression level of transcription factor E2F3 and miR-320 a and let-7d in gastric cancer tissues,we found that the E2F3 is highly expressed,which showed a significant negative correlation between its high expression and low differentiation and T stage in gastric cancer.Mi R-320 a,let-7d in gastric cancer tissues and cells showed low expression,which was associated with the expression level of E2F3.SGC-7901 and MGC-803 cell lines were transfected using miR-320 a and let-7d mimics to validate the affection of overexpression of miR-320 a and let-7d on gene E2F3.The results showed that the expression of E2F3 was significantly decreased while the miR-320 a and let-7d were over expressed.it showed that the expression level of E2F3 was negatively related to let-7d and miR-320 a.Therefore,we can found that miR-320 a and let-7d may directly regulate tumor progression and prognosis by targeting the expression of E2F3. |
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