MicroRNA regulation of epithelial plasticity in cancer

MicroRNAs (miRNAs) are small non-coding RNA molecules capable of regulating multiple target genes through repression of mRNA stability or translation. miRNAs regulate a wide variety of developmental and pathological processes, and many have oncogenic or tumor suppressor activity. Carcinoma cells can undergo changes resembling a partial or transient epithelial–mesenchymal transition (EMT) as part of the metastatic cascade. Numerous miRNAs regulate EMT by targeting genes that control epithelial or mesenchymal characteristics. The involvement of miRNAs in feedback loops with EMT-regulating transcription factors reveals a critical role in governing epithelial plasticity. In this review we summarize miRNAs involved in carcinoma cell plasticity.

► miRNA expression levels may induce or permit carcinoma cells to undergo EMT or MET in response to microenvironmental stimuli.
► Numerous miRNAs are involved in feedback loops with important regulators of normal and pathological EMT.
► miR-200 family members are important regulators of plasticity with targets involved in mesenchymal and stem cell phenotypes.