DDR1 is a target gene of miR-199a-5p. (A) Cells were cotransfected with 200 ng of each vector (pMIR-DDR1-3'-UTR construct or empty pMIR-REPORT firefly luciferase reporter vector, together with beta-galactosidase (β-gal) expression construct pMIR-REPORT β-gal and miR-199a-5p precursor or control miRNA precursor using lipofectamine 2000. Luciferase assays and β-gal enzyme assays were performed 24 hours after transfection in triplicate. Firefly luciferase activity was normalized to β-gal expression for each sample. Data are shown as mean ± SD from 3 independent experiments. *p < 0.05 vs. respective control. (B) HepG2 or (C) SNU-182 cells were transfected with 10 nM miR-199a-5p precursor or 100 nM DDR1-siRNA. DDR1 mRNA expression was assessed by qRT-PCR and normalized to the expression of HPRT1 and SDHA. Cells transfected with control miRNA precursor or control siRNA were used as controls. Data are shown from 3 independent experiments each performed in triplicate as mean ± SD. *p < 0.05 vs. respective controls.