MiR-181b targets related CLL genes. (A) Putative binding site of miR-181b in MCL1 3′-UTRs (TargetScan5.1 Database). Asterisks indicate the nucleotides substituted in miR-181b–predicted target site to perform luciferase assay. (B) MCL1 3′-UTRs regulated by luciferase activity dependent on miR-181b in HeLa cell lines (WT, wild-type; MUT, mutant; P value t test). Error bars indicate SD (mean ± SD), n = 3. Firefly luciferase activity was normalized on Renilla luciferase activity of the gene included in the same vector. (C) Western blot analysis of MCL1 after either scrambled sequence or precursor-miR-181b transfection in HeLa cell line; β-actin has been used as loading control. Cells were collected after 48 and 72 hours of miRNA transfection. (D) Densitometric display of the TCL1, MCL1, and BCL2 Western blot analyses (supplemental Figure 2) normalized on β-actin on samples from patients with CLL with either progressive or stable disease. Asterisks indicate patients in which the protein expression of the miR-181b target genes increase. R indicates correlation factor by Pearson test; and In. time point, intermediate time point.