Dual-luciferase assays were performed using 1 × 104 BCap37 cells per well in a 96-well plate (Corning/Costar, 3499, Acton, MA, USA). After the cells attached for 8 h, they were co-transfected with 50 ng of respective reporter constructs with either 50 nM of miRNA mimics or control miRNA. After 48 h, a Reporter Assay System Kit (Promega, 017319, Beijing, China) was used to measure the luciferase activity. There were three replicates for each transfectant. Firefly luciferase activity was normalized to constitutive Renilla luciferase activity.