BACKGROUND Ectopic expression of miRNAs promotes tumor development and progression.miRNA(miR)-320a is downregulated in many cancers,including gastric cancer(GC).However,the mechanism underlying its downregulation and ...BACKGROUND Ectopic expression of miRNAs promotes tumor development and progression.miRNA(miR)-320a is downregulated in many cancers,including gastric cancer(GC).However,the mechanism underlying its downregulation and the role of miR-320a in GC are unknown.AIM To determine expression and biological functions of miR-320a in GC and investigate the underlying molecular mechanisms.METHODS Quantitative real-time polymerase chain reaction(PCR)was used to determine expression of miR-320a in GC cell lines and tissues.TargetScanHuman7.1,miRDB,and microRNA.org were used to predict the possible targets of miR-320a,and a dual luciferase assay was used to confirm the findings.Western blotting was used to detect the protein levels of pre-B-cell leukemia homeobox 3(PBX3)in GC cells and tissue samples.Cell Counting Kit-8 proliferation,Transwell,wound healing,and apoptosis assays were performed to analyze the biological functions of miR-320a in GC cells.Methylation-specific PCR was used to analyze the methylation level of the miR-320a promoter CpG islands.5-Aza-2’-deoxycytidine(5-Aza-CdR)and trichostatin A(TSA)were used to treat GC cells.RESULTS miR-320a expression was lower in GC cell lines and tissues than in the normal gastric mucosa cell line GES-1 and matched adjacent normal tissues.miR-320a overexpression suppressed GC cell proliferation,invasion and migration,and induced apoptosis.PBX3 was a target of miR-320a in GC.The methylation level of the miR-320a promoter CpG islands was elevated and this was partly reversed by 5-Aza-CdR and TSA.CONCLUSION miR-320a acts as a tumor suppressor and inhibits malignant behavior of GC cells,partly by targeting PBX3.DNA methylation is an important mechanism associated with low expression of miR-320a.展开更多
基金Supported by the Natural Science Foundation of Liaoning Province,No.201602817
文摘BACKGROUND Ectopic expression of miRNAs promotes tumor development and progression.miRNA(miR)-320a is downregulated in many cancers,including gastric cancer(GC).However,the mechanism underlying its downregulation and the role of miR-320a in GC are unknown.AIM To determine expression and biological functions of miR-320a in GC and investigate the underlying molecular mechanisms.METHODS Quantitative real-time polymerase chain reaction(PCR)was used to determine expression of miR-320a in GC cell lines and tissues.TargetScanHuman7.1,miRDB,and microRNA.org were used to predict the possible targets of miR-320a,and a dual luciferase assay was used to confirm the findings.Western blotting was used to detect the protein levels of pre-B-cell leukemia homeobox 3(PBX3)in GC cells and tissue samples.Cell Counting Kit-8 proliferation,Transwell,wound healing,and apoptosis assays were performed to analyze the biological functions of miR-320a in GC cells.Methylation-specific PCR was used to analyze the methylation level of the miR-320a promoter CpG islands.5-Aza-2’-deoxycytidine(5-Aza-CdR)and trichostatin A(TSA)were used to treat GC cells.RESULTS miR-320a expression was lower in GC cell lines and tissues than in the normal gastric mucosa cell line GES-1 and matched adjacent normal tissues.miR-320a overexpression suppressed GC cell proliferation,invasion and migration,and induced apoptosis.PBX3 was a target of miR-320a in GC.The methylation level of the miR-320a promoter CpG islands was elevated and this was partly reversed by 5-Aza-CdR and TSA.CONCLUSION miR-320a acts as a tumor suppressor and inhibits malignant behavior of GC cells,partly by targeting PBX3.DNA methylation is an important mechanism associated with low expression of miR-320a.
