Protein-coding cancer genes as targets of solid cancer miRNA signature components. (A) The 3′ UTR of different cancer protein coding genes enable cancer miRNA regulation. The data present the relative repression of firefly luciferase expression standardized to a transfection control, renilla luciferase. The miRNAs were selected from those differentially regulated in solid cancers as shown in and . PLAG1, pleiomorphic adenoma gene 1; TGFBR2, transforming growth factor, beta receptor II, Rb, retinoblastoma gene. pGL-3 (Promega) was used as the empty vector. miR-20a, miR-26a-1, and miR-106 oligoRNAs (sense and scrambled) were used for transfections. A second experiment using as control a mutated version of each target mRNA lacking the 5′ miRNA-end complementarity site (MUT) is shown at Right. All of the experiments were performed twice in triplicate (n = 6). (B) In cancer patients, the levels of RB1 protein correspond to an inversely correlation with miR-106a expression. For normalization, we used β actin.