miR-21 targets gene and cell transfection efficiency were determined.

<p><b>A.</b> The 3′-UTR of <i>PTEN</i>-mRNA, <i>RECK</i>-mRNA and <i>Bcl-2</i>-mRNA are targets for miR-21 and the seed matching sequences were marked in red. The miRNA targets were predicted by Target Scan Human Release 6.2 (<a href="http://www.targetscan.org" target="_blank">http://www.targetscan.org</a>). <b>B.</b> The expression of green fluorescent protein (GFP) transfected with pGCMV/EGFP-hsa-miR-21 or pGCMV/EGFP-hsa-miR-NC for 48 h was observed using a fluorescent inverted microscope (40×). <b>C.</b> The expression level of miR-21 was analyzed by quantitative real-time PCR at 48 h post-transfection shown in the bar graphs. miRNA abundance was normalized to <i>U6</i> as a reference gene (n = 3, **p<0.01 versus corresponding control). NC means negative control (transfected with pGCMV/EGFP-hsa-miR-NC plasmid), RQ means relative quantitation.