MRNA/miRNA correlations in colorectal cancer: Novel mechanisms in cancer initiation and progression

摘要

miRNAs are small noncoding RNA which are cleaved from 70 to 100 nt endogenous double-stranded precursors. Although their biological role is not fully understood, miRNAs are found in diverse organisms and epigenetically function as negative regulators of gene expression. They are complementary to genomic regions, and one of their modes of action is to bind three prime untranslated region (3'-UTR) and inhibit gene translation. Moreover, they can also function by cleaving and degrading a target mRNA, in which case the miRNA may target sequences outside the 3'-UTR. Functional characterisation of miRNAs will depend heavily on the identification of their specific gene targets. In addition, a number of studies have shown that more than one miRNA can potentially bind to a single targeted gene; hence, multiple miRNAs may cooperatively control the expression of target genes. Numerous bio-informatic methods were developed to high-throughput prediction of miRNA target genes, although it is understood that the presumed targets have to be validated experimentally.