Microrna editing detection and function: A combined in silico and experimental approach for the identification and validation of putative oncogenic targets

MicroRNAs (miRNAs) are a class of ~22 nt noncoding RNAs playing essential roles in the post-transcriptional regulation of gene expression, cell proliferation, and cell differentiation and are often found deregulated in several diseases including cancer. The A-to-I RNA editing, mediated by ADAR enzymes, is a diffuse post-transcriptional mechanism that converts the genetically coded adenosine (A) into inosine (I) at the RNA level. Among different RNA targets, the ADAR enzymes can also edit miRNA precursors. Specifically, a single nucleotide change (A/I) lying within the mature miRNA can alter the miRNA binding specificity and redirect the edited miRNA to a different mRNA target. In several cancer types a consistent deregulation of A-to-I RNA editing machinery also involves important miRNAs (either oncomiRs or tumor-suppressor miRNAs). Herein we describe a combined in silico and experimental approach for the detection of edited miRNAs and the identification and validation of their target genes potentially involved in cancer progression or invasion.