Abstract: Objective：To investigate the effect of miR711 on the characteristics of stemness in gastric cancer stem cells(GCSCs) and its targeted regulation on CD44.ethods：We examined the expression of miR711 in gastric cancer tissues and normal gastric tissues using TCGA database.Human gastric cancer stem cell CSCG and human gastric cancer cell line MKN45 were selected.CSCG were transfected and divided into miRNC group(transfected with miRNC),miR711 group(transfected with miR711mimics) and CSCG group(no transfected).qRTPCR was used to detect the expression of miR711,Bmi1,Sox2,Oct4 and CD44 mRNA.Western blot was used to detect the protein expression of Bmi1,Sox2,Oct4,and CD44.Tumor ball formation test was used to detect the cell stemness.The target effect of miR711 and CD44 was confirmed by bioinformatics methods and the luciferase reporter assay.Results：The expression of miR711 was significantly lower in the gastric cancer tissues than in the normal gastric tissues(P＜0.01).The expression of miR711 in miR711 group was higher than that in miRNC group,CSCG group and MKN45 group(P＜0.01).The mRNA level of Bmi1,Sox2,Oct4 and CD44 in miR711 group were lower than those in miRNC group and CSCG group(P＜0.01).The expression level of Bmi1,Sox2,Oct4,CD44 in miR711 group were lower than those in miRNC group and CSCG group(P＜0.01).At 7 and 14 days,the percentage of suspended cell ball in miR711 group was lower than that in miRNC group and CSCG group(P＜0.01).Compared with WTCD44 group,the luciferase activity of miR711+WTCD44 group significantly decreased(P＜0.01).Conclusion：The overexpression of miR711 can inhibit the stemness of the GCSCs,which may be achieved by downregulating the expression of CD44 gene.

Key words: miR711, CD44, gastric cancer stem cells, stem