LncRNA RPSAP52 Promotes Progression Via Modulating MiR-665/STAT3 In Gastric Carcinoma Cells

Objective:The purpose of this study was to investigate the biological function and mechanism of lncRNA RPSAP52 in gastric cancer.Methods:the differential expression of lncRNA RPSAP52 was detected by RT qPCR between gastric cancer cells and normal gastric tissue cells.By transfecting RPSAP52 shRNA into gastric cancer cells,RT-qPCR,CCK-8,clone formation experiment,flow cytometry to detect the apoptosis rate and cell cycle,and analyze the phenotype and biological function of lncRNA RPSAP52 in gastric cancer cells.The expression site of lncRNA RPSAP52 in cells was determined by subcellular localization.The expression of miRNA-665 was detected by RT qPCR by transfecting RPSAP52 shRNA.The interaction between RPSAP52 and miRNA-665 was verified by double luciferase reporter gene detection system and RNA pull down.By transfecting miRNA-665 mimics into gastric cancer cells,RT qPCR,CCK8,clone formation experiment,flow cytometry to detect the apoptosis rate and cell cycle,and analyze the phenotype and biological function of mir-665 in gastric cancer cells.The interaction between miRNA-665 and STAT3 was verified by double luciferase reporter gene detection system and RNA pull down.After STAT3 shRNA in gastric cancer cells,WB,CCK8,clone formation experiment and flow cytometry were used to detect the apoptosis rate and cell cycle,so as to analyze the phenotype and biological function of STAT3 in gastric cancer cells.RT qPCR was used to detect the expression of mir-665,STAT3 and lncRNA RPSAP52 in transfected gastric cancer cells to verify the regulatory relationship between lncRNA RPSAP52/mir-665/STAT3.Western blot was used to detect the expression of STAT3,Bcl-xl,VEGF,c-MYC,MMP-2,MMP-9 in gastric cancer cells to analyze the effect of lncRNA RPSAP52 on STAT3 signaling pathway.The phenotype and biological function of lncRNA RPSAP52 in tumor were analyzed by establishing tumor bearing mouse model,counting tumor size and weight,HE staining,IHC staining and western blot.Results:lncRNA RPSAP52 increased significantly in gastric cancer cells.Down regulating the expression of lncRNA RPSAP52 can inhibit the proliferation of gastric cancer cells,induce G0-G1 arrest and accelerate the apoptosis of gastric cancer cells.The double luciferase reporter gene detection system and RNA pull down showed that miRNA-665 interacted with lncRNA RPSAP52,and miRNA-665 interacted with STAT3.MiRNA-665 overexpression and STAT3 deletion have the same function as lncRNA RPSAP52 deletion in gastric cancer cells.LncRNA RPSAP52 can affect the expression of multiple targets downstream of STAT3 pathway.Down regulate the expression of lncRNA RPSAP52,inhibit tumor growth in vivo and accelerate tumor apoptosis.Conclusion:lncRNA RPSAP52 negatively regulates miRNA-665 in gastric cancer cells;MiRNA-665 negatively regulates STAT3 in gastric cancer cells;STAT3 and lncRNA RPSAP52 is a oncogene and miRNA-665 is a tumor suppressor gene;LncRNA RPSAP52 plays an anticancer role in gastric cancer by regulating miRNA-665/STAT3.The regulation between lncRNA RPSAP52/miR-665/STAT3 conforms to the regulation mechanism of ceRNA.