MicroRNA-182-5p targets a network of genes involved in DNA repair

MicroRNAs are non-coding regulators of gene expression, which act by repressing protein translation and/or degrading mRNA. Many have been shown to drive tumorigenesis in cancer, but functional studies to understand their mode of action are typically limited to single target genes. In this study we use synthetic biotinylated miRNA to pull down endogenous targets of miR-182. We identified over 1000 genes as potential targets of miR-182, most of which have a known function in pathways underlying tumour biology. Specifically, functional enrichment analysis identified components of both the DNA damage response pathway and cell cycle to be highly represented in this target cohort. Experimental validation confirmed that miR-182 mediated disruption of the homologous recombination (HR) pathway is a consequence of its ability to target multiple components in that pathway. Although there is a strong enrichment for the cell cycle ontology, we do not see a direct biological effect as a consequence of miR-182 over expression. We highlight targets which could be responsible for miR-182 mediated disruption of other biological processes attributed in the literature so far. Finally we show that miR-182 is highly expressed in a panel of human breast cancer samples highlighting its role as a potential oncomir in breast cancer. HEK293T cells were transfected with biotinylated miR-182 or a mock control. The miRNAs and target mRNA were pulled down with streptavidin and compared to the control.