microRNA-21 is a very popular study target these days, which is not surprising given its overexpression in many human tumors, and was profiled on the miRNA blog back in February as the “microRNA of the week”.
Researchers at Yale have now demonstrated what they call ‘oncomiR addiction’ (the dependence of some cancer types on certain microRNAs for maintenance of the malignant phenotype) for miR-21 by pre-B-cell lymphoma. They show for the first time in vitro that overexpression of miR-21 leads to a pre-B malignant lymphoid-like phenotype and that when miR-21 is inactivated, the tumors regress completely in a few days. Their research not only demonstrates that mir-21 is a genuine oncogene but that tumors can also become addicted to oncomiRs. This and other work supports miR-21 as a drug target for treatment of human cancers.
Medina PP, Nolde M, Slack FJ (2010) OncomiR addiction in an in vivo model of microRNA-21-induced pre-B-cell lymphoma. Nature [Epub ahead of print]. [abstract]