Screening Of Gastric Cancer Differentiation-related MiRNAs And Bioinformatics Analysis Of Their Functions

Background:Gastric cancer is one of the most common malignant tumors of the digestive tract in the world and the second leading cause of cancer-related deaths in china.China is a country with a high incidence of gastric cancer,accounting for about 50% of the world ’s morbidity and mortality.There are an estimated 679,000 diagnosed cases and488,000 deaths each year.Although the overall incidenceand mortality of gastric cancer are showing a downward trend,due to the large population base and aging population in China the trend is increasing,and the burden of gastric cancer is still very serious.Due to the lack of effective early diagnostic markers,low tumor differentiation and high recurrence and metastasis rates,the 5-year survival rate of gastric cancer patients is only20%.The degree of differentiation of tumor cells is an important factor affecting the prognosis of gastric cancer.Gastric cancer cells with different degrees of differentiation have significant differences in growth rate and metastatic invasion ability.At present,the molecular mechanism related to gastric cancer differentiation is not clear.mi RNA is a type of endogenous non-coding RNA that has been studied in depth.It is involved in regulating various pathophysiological processes of the body and mediates the occurrence and development of tumors such as gastric cancer.Gastric cancer cell proliferation,invasion and metastasis,and changes in biological characteristics are related to the misregulation of mi RNAs.However,the current research on the function of mi RNA in gastric cancer differentiation is very rare.Objective:In this paper,differentially expressed mi RNAs related to gastric cancer differentiation were screened out by mi RNA chips.The functional role of differentially expressed mi RNAs and their target genes in gastric cancer was initially explored using bioinformatics methods.In order to reveal molecular mechanisms related to gastriccancer differentiation and find new diagnosis markers and molecular therapeutic targets provide theoretical basis.Methods:1.In this study,differential mi RNA expression profiles of human undifferentiated gastric cancer cell line HGC-27 and medium differentiated gastric cancer cell line SGC-7901 cultured in vitro were analyzed by mi RNA chips.2.Use the Target Scan7.1,mi RDB,and micro T-CDS three mi RNA target prediction websites and the experimentally verified micro RNA-target interaction database mi RTar Base to screen out the target genes set of mi RNA.Using DAVID’s online bioinformation resource gaze to visualize the gene ontology analysis and KEGG pathway enrichment analysis of target genes.The target gene-coding protein interaction network is constructed on the STRING website.The MCODE and Cytohubba plug-ins in Cytoscape were used to identify the significant modules and central genes of mi RNA target genes.3.Extract the gastric cancer-related gene expression profile chip GSE54129 data from the GEO database,use the GEO2 R data processor to screen genes that are differentially expressed between gastric cancer samples and normal samples,and obtain the intersection of the differential genes and the mi RNA center target genes through the Veen online cross-intersection tool As a key target gene of mi RNA in gastric cancer.4.The prognostic analysis of key target genes in gastric cancer is derived from the Kaplan Meier-plotter platform.Results:1.The mi RNA chip screened 28 mi RNAs for differential expression in human undifferentiated gastric cancer cell line HGC-27 and moderately differentiated gastric cancer cell line SGC-7901.Based on the previous research of this group,the sensitivity of these two cells to cyclin dependent kinase inhibitor(CDKI)is significantly different(see the graduate thesis of the last post).Based on related literature,it is speculated that some differentially expressed mi RNAs may be involved in regulating cell cycle Signaling Pathways and Sensitivity to CDKI Treatment.2.Select mi R-503-5p related to the differentiation of gastric cancer cells to verify the results of the chip.The results showed that the expression of mi R-503-5p in HGC-27 was significantly lower than that of SGC-7901,which was consistent with the results of the chip.The expressions were lower than those in gastric mucosa epithelial cells(P <0.05).3.Four mi RNA target databases have screened 109 target genes for mi R-503-5p,which are mainly present in cell components such as cytoskeleton,cyclin-dependent kinase,centrosome,and are enriched in cell cycle,focal adhesions,m TOR And other tumor-related signaling pathways.The protein-protein interaction network encoded by the target genes of mi R-503-5p was constructed to obtain significant modules and central genes,and subsequent KEGG pathway enrichment analysis results showed that p53 and the cell cycle signal transduction pathway were mi R-503-5p and the target genes The key signaling pathways at work.4.After processing the GSE54129 chip data,a total of 3746 genes were differentially expressed in gastric cancer,including 1760 genes up-regulated in gastric cancer tissues and 1986 genes down-regulated in gastric cancer tissues.Seven intervening genes belonging to the differentially expressed genes of gastric cancer and the central target gene of mi R-503-5p were obtained using the venn online website,which are the key target genes of mi R-503-5p in gastric cancer.The key target genes of mi R-503-5p: RNF144 B,PIK3R1,IGF1 R,FGFR1,E2F3,AKT3,and AGO1 are all highly expressed in gastric cancer tissues.Among them,IGF1 R,E2F3,AKT3,and AGO1 are associated with poor survival of gastric cancer and may be related to the occurrence of gastric cancer Play an important role in development.Conclusion:1.Preliminary screening of differential mi RNAs related to gastric cancer differentiation.It is speculated that they may be related to gastric cancer differentiation and cell cycle molecular regulation mechanisms.It provides a theoretical basis for revealing molecular mechanisms related to gastric cancer differentiation and may be sensitive for regulating CDKI treatment.To be confirmed by follow-up studies.2.The expression of mi R-503-5p in human gastric cancer cells is significantly lower than that of gastric mucosal epithelial cells,and the down-regulation is more significant in poorly differentiated gastric cancer cell lines.It is speculated that it may be used as a tumor suppressor to participate in gastric cancer cells.Differentiation and morphological maintenance.3.mi R-503-5p and target genes related to gastric cancer differentiation are mainly involved in signal pathways closely related to gastric cancer such as P53 and cell cycle.4.RNF144 B,PIK3R1,IGF1 R,FGFR1,E2F3,AKT3,and AGO1 are the key target genes of mi R-503-5p in gastric cancer.Among them,IGF1 R,E2F3,AKT3,and AGO1 are highly expressed in gastric cancer and are associated with poor prognosis of patients.The differentially expressed mi RNA and target genes obtained in this paper may be used as potential biomarkers for predicting accurate diagnosis and treatment of gastric cancer.