| Objective:The pathogenesis of gastric cancer is more complicated.Circular RNA(circRNA)plays an important role in the pathogenesis of gastric cancer.It can act as a competitive RNA(ceRNA)for microRNA(miRNA),and then participate in the regulation of the expression of miRNA target genes,thereby regulating cellular malignant organisms.However,whether circDONSON can participate in the occurrence,development and cisplatin resistance process of gastric cancer by regulating the miR-802/BMI1 molecular axis is still unknown.Therefore,this study mainly explored the effects of circDONSON on gastric cancer cell proliferation,migration,invasion,apoptosis and cisplatin resistance,and its regulation of miR-802/BMI1 molecular axis.Methods:qRT-PCR and Western blot were used to detect gastric cancer and corresponding adjacent tissues,cisplatin-sensitive gastric cancer tissue,cisplatin-resistant gastric cancer tissue,gastric cancer cell lines(AGS,HGC-27),and gastric epithelial cells(GES-1)The expression levels of circDONSON,miR-802 and BMI1 in cisplatin-resistant gastric cancer cells(AGS/DDP,HGC-27/DDP);Pearson method was used to analyze the correlation of circDONSON,miR-802 and BMI1 expression in gastric cancer tissues;Taking AGS/DDP and HGC-27/DDP cells as the research object,si-NC,si-circDONSON,miR-NC mimic,miR-802 mimic,anti-miR-NC,anti-miR-802,si-circDONSON,anti-miR-NC,si-circDONSON and anti-miR-802,pcDNA-NC,pcDNA-BMI1,miR-802 mimic and pcDNA-NC,miR-802 mimic and pcDNA-BMI1 were transfected to AGS/DDP,HGC-27/DDP cells.qRT-PCR and Western blot were used to detect the expression levels of circDONSON,miR-802,and BMI1.Actinomycin D and RNase R experiments were used to verify the stability of circDONSON.The thiazole blue colorimetric method(MTT),plate clone formation experiment,flow cytometry and Transwell experiment were used to detect cell viability,cisplatin IC50 value,clone formation ability,apoptosis rate,migration and invasion ability;dual luciferase report The system detects the targeting relationship between circDONSON and miR-802 and miR-802 and BMI1;Western blot is used to detect the expression of cell proliferation-related proteins Cyclin D1 and p27;Cisplatin(3 mg/kg)is injected into the abdominal cavity every 3 days after subcutaneous injection One injection,27 days after treatment,the mice were sacrificed to take the transplanted tumors,and they were divided into sh-NC+PBS group,sh-NC+DDP group,sh-circDONSON+PBS group,sh-circDONSON+DDP group;the volume and weight of the transplanted tumor were measured;QRT-PCR and Western blot to detect the expression levels of circDONSON,miR-802 and BMI1 in transplanted tumors.Results:Compared with adjacent tissues,the expression of circDONSON and BMI1 in gastric cancer tissue was significantly increased(P<0.05),and the expression of miR-802 was significantly reduced(P<0.05);compared with cisplatin-sensitive gastric cancer tissue,cisplatin was resistant to The expression of circDONSON and BMI1 in drug-induced gastric cancer tissues was significantly increased(P<0.05),and the expression of miR-802 was significantly reduced(P<0.05);compared with gastric epithelial cells GES-1,gastric cancer cells AGS,HGC-27 and gastric cancer The expression of circDONSON and BMI1 in cisplatin-resistant cells AGS/DDP and HGC-27/DDP were significantly increased(P<0.05),and the expression of miR-802 was significantly decreased(P<0.05);Actinomycin D and RNase The R experiment confirmed the stability of the structure of circDONSON;circDONSON was negatively correlated with miR-802(r=-0.8581,P<0.0001),miR-802 was negatively correlated with BMI1(r=-0.8192,P<0.0001),and circDONSON was negatively correlated with BMI1 Positive correlation(r=0.8619,P<0.0001);Compared with the si-NC group,the cell viability,IC50 value,Cyclin D1 expression of the si-circDONSON group decreased(P<0.05),and the number of clone formation,migration and invasion cells decreased(P<0.05),the apoptosis rate and the expression of p27 increased(P<0.05);the dual luciferase detection system confirmed that circDONSON can target miR-802 and negatively regulate the expression of miR-802;and Compared with the si-circDONSON+anti-miR-NC group,the cell viability,IC50 value and Cyclin D1 protein level of the si-circDONSON+anti-miR-802 group were significantly increased(P<0.05),the number of clone-forming cells,the number of migration and invasion cells Increased(P<0.05),cell apoptosis rate and expression of p27 decreased(P<0.05);dual luciferase detection system confirmed that miR-802 can target BMI1 and can negatively regulate the expression of BMI1;and miRCompared with NC mimic group,the cell viability,IC50 value,Cyclin D1 expression of miR-802 mimic group decreased(P<0.05),the number of clone formation,migration and invasion cells was significantly reduced(P<0.05),apoptosis rate and p27 The expression increased(P<0.05);compared with the miR-802 mimic+pcDNA-NC group,the cell viability,IC50 value and Cyclin D1 expression of the miR-802 mimic+pcDNA-BMI1 group increased(P<0.05),and the clone was formed The number of cells,the number of migrating cells,and the number of invasive cells increased significantly(P<0.05),and the apoptosis rate and expression of p27 decreased(P<0.05);and Compared with the sh-NC+PBS group,the volume and weight of the transplanted tumor,the expression of circDONSON and BMI1 in the sh-NC+DDP group were reduced(P<0.05),and the expression of miR-802 increased(P<0.05);-Compared with the circDONSON+PBS group,the volume and weight of the transplanted tumor,the expression level of circDONSON and BMI1 in the sh-circDONSON+DDP group were reduced(P<0.05),and the expression level of miR-802 was significantly increased(P<0.05).Conclusions:The expression levels of circDONSON and BMI1 in gastric cancer tissues,cell lines,and cisplatin-resistant tissues and cell lines increase,while the expression levels of miR-802 decrease.Silencing circDONSON can promote the expression of miR-802 and inhibit the expression of BMI1.Inhibit the proliferation,migration and invasion of cisplatin-resistant gastric cancer cells,induce cell apoptosis,and enhance the sensitivity of cells to cisplatin. |
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