Preliminary Investigation Of The Function Of Has_circ₀008797 In Cisplatin Resistance In Gastric Cancer

Purpose: This study aimed to investigate the relationship between circRNA（hsa_circ₀008797）and cisplatin resistance in gastric cancer,to predict the molecular mechanism and signaling pathway of circRNA involved in the regulation of tumor through biological information,and to predict the binding of miRNA and mRNA to hsa_circ₀008797.Its cisplatin resistance mechanism in gastric cancer cells was preliminarily explored.Method: Serum was collected from patients with advanced gastric cancer at the time of initial diagnosis and after chemotherapy（based on platinum drugs）.Then RNA microarrays were used to screen the differentially expressed circRNAs in patients with advanced gastric cancer before and after chemotherapy,and the differential expression profiles of circRNAs were constructed.PCR and agarose gel electrophoresis were used to detect the expression of circRNAs in cisplatin sensitive and drug-resistant cell lines of gastric cancer.The cisplatin-sensitive and drug-resistant cells were transfected with shRNA and over-expression plasmid,and the expression level of hsa_circ₀008797 in each cell was changed.The cell viability was determined by CCK-8 method and the apoptosis rate was detected by flow cytometry,which was to verify the relationship between hsa_circ₀008797 and cisplatin resistance in gastric cancer cells.Furthermore,bioinformatics was used to predict the relationship between hsa_circ₀008797 and miRNA.GO enrichment and KEGG pathway analysis of circRNA regulate tumor pathogenesis and involved cellular signal transduction pathways.Results: The circRNA microarray showed that after chemotherapy,there were significant differences in 11 circRNAs in the serum of patients with gastric cancer,and the expression of hsa_circ₀008797 was decreased.The results of PCR and agarose gel electrophoresis showed that only 3 circRNAs（hsa_circ₀008797,hsa_circ₀017377,hsa_circ₀069376）were expressed in gastric cancer cell lines SGC7901 and SGC7901/DDP.The qRT-PCR results showed that the expression level of hsa_circ₀008797 in cisplatin-sensitive gastric cancer cell lines was higher than that in cisplatin-resistant gastric cancer cell lines.Besides,after transfecting shRNA,it could effectively knock down the expression level of hsa_circ₀008797 in SGC7901 cells;after expression,it can effectively increase the expression level of hsa_circ₀008797 in SGC7901/DDP cells.The CCK-8 method showed that after treatment of SGC7901 cells with the same concentration of cisplatin,the cell viability of the hsa_circ₀008797 expression knockdown group was higher than that of the control group,and meanwhile the apoptosis rate decreased through flow cytometry analysis,so the cisplatin resistance of the cells increased.Similarly,after treatment of SGC7901/DDP cells with the same concentration of cisplatin,the cell viability of the hsa_circ₀008797 over-expression group was higher than that of the control group,with the apoptosis rate increased and thus the cisplatin resistance of the cells decreased.In addition,after removing the stimulation of cisplatin on SGC7901/DDP cells,it was found that the expression level of hsa_circ₀008797 increased gradually.After cisplatin was re-treated,the expression level of hsa_circ₀008797 decreased rapidly.CircRNAs may be involved in the regulation of the pathogenesis of a variety of diseases and in multiple cellular signaling pathways.Hsa_circ₀008797 can be used as a plurality of miRNA sponges,thus acting on target genes.Cisplatin inhibited the expression of hsa_circ₀008797 in gastric cancer cells.Bioinformatics analysis revealed that circRNA was involved in the regulation of multiple signaling pathways and regulated target genes in combination with multiple microRNAs.Conclusion: The expression level of hsa_circ₀008797 is correlated with the resistance of SGC7901 cells and SGC7901 / DDP cells to cisplatin.Cisplatin inhibits the expression of hsa_circ₀008797 in gastric cancer cells.Biological information analysis reveals that circRNA is involved in the regulation of multiple signaling pathways and could regulate target genes in combination with multiple microRNAs.