Screening And Analysis Of Circulating RNA Related To Gastric Cancer

Background : Gastric cancer?GC?is one of the most common malignant gastrointestinal tumors with high morbidity and mortality,which affects the public health of the people.Although great progress has been made in the diagnosis and treatment of gastric cancer since the rapid development of medical and health care in the 21 st century,due to the lack of specific symptoms in the early stage of gastric cancer and the underdevelopment of our economy,Most patients are already in the middle or late stages of diagnosis,with a 5-year survival rate of only 30% to 50%.Therefore,it is urgent to develop molecular markers for early sensitive and specific diagnosis of gastric cancer.CircularRNA?circRNAs?is a research hotspot in the field of non-coding RNA in recent years,and it has been proved to play an important role in many diseases,including cancers.The aim of this experiment was to find and verify the different circular RNAs,by screening the gastric cancer tissues and matched paracancerous tissues of 5 patients with gastric cancer,and to provide the basic research for establishing the "diagnosis and treatment mode of gastric cancer associated ring RNAs".Method:In this study,the differential expression of circRNAs was detected by screening 5 gastric cancer tissues and matched adjacent normal tissues by gene chip technique,and the circular RNA expression profile in gastric cancer was established.Furthermore,the predicted target genes of circular RNA were analyzed by GO and KEGG pathway,and the possible function of them was elucidated.We selected 4 cases of circular RNAs,with the highest up-regulation or down-regulation in 36 pairs of gastric cancer and paired tissues by qRT-PCR technique,and predicted their microRNA sites,so as to reveal the possible mechanism of action.We selected 4 circular RNAs with up-regulation and down-regulation,and verified them in 36 pairs of gastric cancer and matched tissues by qRT-PCR,and predicted their microRNA action sites to reveal the possible mechanism.Results:The microarray results showed that there were 99 differentially expressed circular RNAs compared with matched normal gastric mucosa tissue samples.Among them,44 CircRNAs were up-regulated and 55 CircRNAs were down-regulated in gastric cancer.In order to analyze the role of these circularRNAs in the carcinogenesis and progression of gastric cancer,the target genes were analyzed by GO and KEGG pathway.The results showed that these genes were mainly involved in the biological processes?BP?such as active regulation of cell metabolism?GO:0048518?,systemic development?GO:0048731?and multicellular development?GO:0007275?in the three major parts of GO analysis.Cellular components?CC?such as cell link?GO:0030054?,intimal system?GO:0012505?and membrane-binding organelle?GO:0043227?,protein binding function?GO:0005515?,transcriptional activation activity,RNA polymerase ? transcriptional regulation?GO:0001228?and other molecular functions?MF?.In the KEGG Pathway,these differential genes mainly relate to the protein-polysaccharide pathway and MAPK pathway in the cancer.From these differentially expressed circular RNA,the four circular RNA with the most significant up-and down-regulation differences were further selected for the verification of large clinical samples,namely circ₀004104?up-regulated 4.408 times?,circ₀005615?up-regulated 2.651 times?,Circ₀004789?down 5.510 times?and circ₀023736?down 4.769 times?.The expression of circ₀004104,circ₀005615,circ₀004789 and circ₀023736 was further verified by qRT-PCR in 36 gastric cancer tissues and matched paracancerous tissues.The results showed that there was no significant difference in the expression of four cyclic RNA molecules in the microarray and the expression of qRT-PCR?P values of circ₀004104,circ₀005615,circ₀004789 and circ₀023736 were 0.374,0.147,0.51 and 0.087,respectively?.The use of circular RNA as a microRNA sponge to regulate gene expression is one of the most important roles of circular RNA.In cancer,participation in cancer pathways through interaction with cancer-associated circular RNA is also considered to be the most worthy of research.Therefore,based on TargetScan and miRanda algorithms,our group used Arraystar's microRNA target prediction software to predict a variety of microRNAs that can interact with circ₀004104,circ₀005615,circ₀004789,and circ₀023736.Conclusion:In this study,we screened and constructed the circular RNAs expression profile of gastric cancer based on gene chip,and verified the microarray results by qRT-PCR.Circ₀004104,circ₀005615,circ₀004789 and circ₀023736 may play an important role in the carcinogenesis and development of gastric cancer by using bioinformatics methods to predict the presence of multiple microRNA binding sites.