Objective To explore the effect of long non-coding RNA CASC11(lncRNA CASC11)on the proliferation and invasion of colon cancer cells by targeting and regulating miR-146a-3p and its possible mechanism.Methods The expressions of lncRNA CASC11 and miR-146a-3p in three different human colon cancer cell lines HCT116,SW620 and SW480 were detected by real-time fluorescence quantitative PCR(qRT-PCR),and SW620 cells cultured in vitro were randomly divided into control group(untreated group),lncRNA CASC11 siRNA group,lncRNA CASC11 siRNA negative control group and lncRNA CASC11 siRNA+miR-146a-3p inhibitor co-transfection group.After corresponding treatment,the proliferation activity of SW620 cells in each group was detected by MTT and EdU staining;the invasion ability of SW620 cells was detected by Transwell chamber test;immunofluorescence staining(ICF)was used to detected the expression of apoptosis proteins Bax and Bcl-2 in each group;mRNA levels of miR-146a-3p and epithelial-mesenchymal transition marker proteins Vimentin and E-cadherin were detected by qRT-PCR and Western blotting;dual luciferase reporter assay was used to detect the targeting regulation effect of lncRNA CASC11 on miR-146a-3p in SW620 cells.Results Compared with human colonic mucosal epithelial cells,the expressions of ln-cRNA CASC11 in HCT116,SW480,and SW620 were significantly increased,while the expression of miR-146a-3p was signifi-cantly decreased(P＜0.05).Compared with the control group,the cell viability,EdU positive rate,invasive cell number and Vi-mentin mRNA expression in the lncRNA CASC11 siRNA group were decreased(P＜0.05),while the cell Bax/Bcl-2 ratio,miR-146a-3p and E-cadherin mRNA expression were increased(P＜0.05).There was no significant difference in the results between the control group and lncRNA CASC11 siRNA negative control group(P＞0.05);compared with the lncRNA CASC11 siRNA group,the cell viability and EdU positive rate,the number of invasive cells,and the expression of Vimentin mRNA were in-creased in co-transfection group(P＜0.05),while the ratio of Bax/Bcl-2,miR-146a-3p and E-cadherin mRNA expression were decreased(P＜0.05).In SW620 cells,lncRNA CASC11 could target miR-146a-3p and upregulate the expression of downstream c-Met gene.Conclusion lncRNA CASC11 mediates the biological behavior of colon cancer cells by targeting downregulation of miR-146a-3p.Knockdown of lncRNA CASC11 can promote the expression of miR-146a-3p and inhibit the proliferation and in-vasion of colon cancer cells.