The Regulatory Function Analysis For CircTNFRSF11A/let-7g-5p/CDK2 Axis In Gastric Cancer

Gastric cancer is one of the most common malignancy in digestive system.Exceptionally in China,gastric cancer still takes away over half a million peoples’ life,although after decades’years’ efforts.Gastric cancer is also a kind of complex human disease.During the generation of gastric cancer,multi-kinds of molecules are involved,including transcription factors as well as non-coding RNAs.The complicated interactions among these functional molecules totally together construct a molecular function regulatory network,which would help a lot in underling the molecular mechanism of gastric cancer generation.Circular RNAs(circRNAs)is one of the most recently identified endogenous functional molecules,the expression of which is tissue specific,condition specific and disease specific.At transcript level and post-transcript level,circRNAs can control the cell life by function as miRNA sponges,transcription regulators and so far as to coding special functional proteins.With a view to the expression of circRNAs is significantly aberrant regulated before the occurrence of disease,the circRNAs expression patterns can accurately represent the condition of cell and even the whole body.So systemically analyze the gastric caner specific circRNAs expression profiles,analysis the interaction among circRNAs,miRNAs,mRNAs,proteins and any other functional molecules,would not only build the foundation of underlining the molecular mechanism of gastric cancer generation,but would also bring us great benefits in the field of gastric caner early diagnosis,clinical individualized treatments and related researches.In this study,we have detected the circRNAs expression profiles via high-throughput ArrayStar Human Circular RNA Microarray.Through integrating the transcriptome data,we obtained in this work and genomics data we detected in previous studies,we predicted the interaction relationships among circRNAs,miRNAs and mRNAs by biostatistic and bio informatics methods.Following which,we have constructed a circRNAs-centric functional regulatory network.Through GO annotation and KEGG enrichment analysis,we analyzed the regulatory function of the circRNAs-centric functional regulatory network we built.Focused on cancer associated pathways and biological processes,we have also extracted the function guided circRNAs regulatory modules,and identified a pro-tumorigenic module"circTNFRSF11A/let-7g/CDK2".Further molecular function analysis showed that the high expression level of circTNFRSF11A significantly trigger the proliferation,migration,invasion of gastric cancer cells,and promote the cell stage transition from G1 stage to S stage.Part One Construction and Analysis of CircRNAs Centric Molecular Function Regulatory Networks in Gastric Cancer.Through circRNAs expression profiles analysis,we have identified 197 differentially expressed circRNAs in gastric cancer tissues,among which 161 were up-regulated and 36 were down-regulated.Utilizing bio-statistic and bioinformatics methods,we have predicted the interactions among circRNAs as well as any other functional molecules,and constructed a circRNAs centric molecular function regulatory network in gastric cancer.Based on the GO annotation and KEGG pathway enrichment analysis,we have found that the circRNAs regulatory network was involved in the regulation of cancer related signaling pathway and biological processes,such as "CELL CYCLE","P53 SIGNALING PATHWAY","CENTRAL CARBON METABOLISM IN CANCER" as well as“ECM-RECEPTOR INTERACTION".Then,we have exacted the functions specific circRNAs regulatory modules,and we identified the "circTNFRSF11A/let7g/CDK2" module would play an important role in regulation of gastric cancer cell proliferation,migration,invasion and cell cycle stage transition.Part Two Molecular Function Analysis for circTNFRSF11A in Generation and Deterioration of Gastric Cancer.Following the results in first part of this study,we verified the high expression level of circTNFRSF11A in gastric cancer tissues and cell lines and identified the interaction between circTNFRSF11A and let-7 family members.Through knockdown the expression level in gastric cancer cell line SGC-7901 and MGC-803 by shRNA,we demonstrated that the knockdown of circTNFRSF11A significantly reduced the proliferation,migration,invasion activities and xenografted tumor formation abiliity of gastric cancer cells,and significantly repressed the cell cycle in Gl/S transition.Let-7g mimic was transfected into SGC-7901 and MGC-803 cell lines,the over-expression of let-7g significantly reduced the expression of CDK2 at mRNA level and protein level.Meanwhile,the luciferase reporter gene experiment also proved that let-7g would directly bind to the position 412-435 in 3’UTR region of CDK2.And all in all,we think that circTNFRSF11A would control the generation and deterioration of gastric cancer by circTNFRSF11A/let7g/CDK2 axis.