Effects of selected miRNAs on TWIST 3′-untranslated region (UTR). Twelve miRNAs potentially able to regulate TWIST 3′-UTR were selected based on TargetScan prediction software and individually co-transfected with a TWIST-3′UTR-luciferase reporter in MG-63 cells. Among the selected miRNAs, miR-33a, miR-25 and miR-363 were differentially expressed between chemoresistant and control osteosarcoma tissues based on results of the microarray analysis. miRNAs that significantly reduced renilla luciferase activity compared to the control miR-Vec (hTR) (designated as 1, cut off value: 0.8) were selected for validation (light bars). *p < 0.05 vs 0.8 (cut off value).