microRNAs (miRNAs) are non coding RNAs with different biological functions and pathological implications. Given their role as post-transcriptional gene expression regulators, they are involved in several important physiological processes like development, cell differentiation and cell signaling. miRNAs act as modulators of gene expression programs in different diseases, particularly in cancer, where they act through the repression of genes which are critical for carcinogenesis. The expression level of mature miRNAs is the result of a fine mechanism of biogenesis, carried out by different enzymatic complexes that exert their function at transcriptional and post-transcriptional levels. In this review, we will focus our discussion on the alterations in the miRNA biogenesis machinery, and its impact on the establishment and development of cancer programs.
Keywords: Ago2, Argonaute 2 protein; Ars2, Arsenic Resistance protein 2; DGCR8, DiGeorge syndrome Critical Region 8 protein; EMT, epithelial–mesenchymal transition; KSRP, KH-type splicing regulatory protein; MK2, MAPK-activated protein kinase 2; PABP, poly(A)-binding protein; PACT, kinase R–activating protein; PRC2, Polycomb repressor complex; RISC, RNA-induced silencing complex; TRBP, TAR RNA binding protein; TUT4, terminal uridine transferase-4; XPO5, exportin 5; cancer; cellular signaling; circRNA, circular RNA; hnRNPs, heterogeneous nuclear ribonucleoproteins; miRNA biogenesis; miRNAs, microRNAs.