MicroRNAs: novel mediators of resistance to microtubule-targeting agents.

MicroRNAs (miRNAs) are small, non-coding RNAs that act as expression regulators of genes involved in diverse cellular processes, including cell proliferation, differentiation, and apoptosis. Abnormal expression of miRNAs can have profound effects on cellular function, and miRNAs are implicated in tumourigenesis either as oncogenes or tumour suppressors. Deregulated miRNAs have been shown to have a role in the resistance of cancer cells to microtubule-targeting agents (MTAs). Here, we discuss how altered expression of miRNAs mediates resistance to clinically useful MTAs, such as paclitaxel and vincristine. Understanding the molecular role of miRNAs in drug resistance would help improve therapeutic efficacy of these agents by helping circumvent the problem of drug resistance.