ABSTRACT
AIM:To explore the effect of microRNA-221 (miR-221) on the proliferation of lung cancer A549 cells, and to investigate its mechanism .METHODS: The A549 cells were transfected with miR-221 mimics by Lipo-fectamine 2000.The expression of miR-221 was detected by RT-qPCR.The expression of PTEN at mRNA and protein le-vels was detected by RT-qPCR and Western blot , respectively .The cell proliferation was examined by CCK-8 assay and colony formation assay.The 3'-UTR of PTEN was cloned into luciferase reporter vector and its enzymatic activity was detec-ted to verify whether miR-221 targeted to PTEN.RESULTS:The expression level of miR-221 in the A549 cells was sig-nificantly increased after transfection with miR-221 mimics as compared with negative control group and blank group ( P<0.01).The mRNA and protein levels of PTEN were significantly down-regulated compared with control group and blank group ( P <0.05 ) .In addition , miR-221 over-expression significantly promoted the proliferation of A 549 cells ( P <0.05).Moreover, miR-221 inhibited the enzymatic activity of luciferase reporter vector of PTEN.CONCLUSION:Over-expression of miR-221 significantly promotes the proliferation ability of human lung cancer A 549 cells by down-regulation of PTEN.