Targeting of IGF1R by let-7d-5p as shown in luciferase assays. (A) The seed sequences (boxed) of the three putative let-7d-5p-targeted sequences in IGF1R (see also Figure 3 for the designations and locations of IGF1R-1, -2 and -3). The mutated nucleotides are indicated by arrows and lowercase letters. The nucleotide positions of the sequences harboring the targeted site are shown above the sequences in reference to NM_000875. (B) Luciferase assays of transfection of the wild-type (WT) and mutant (Mut) luciferase constructs alone, or in the presence of a let-7d-5p mimic (5p) or a negative control (NC). Relative luciferase activity (RLA) values were calculated relative to the wild-type or mutant construct only, which were arbitrarily set as 1.0. The data were obtained from three independent experiments. **p < 0.001.