The emerging role of noncoding RNAs in colorectal cancer chemoresistance.

Background: Colorectal cancer (CRC) is the third most prevalent cancer in the world and one of the most lethal human malignancies. Chemotherapy with 5-fluorouracil, platinum, hydroxycamptothecin, vincristine, methotrexate, irinotecan, paclitaxel and/or cetuximab has significantly improved the survival of CRC patients. However, most CRC patients eventually develop chemoresistance, resulting in a poor prognosis. The mechanisms involved in CRC chemoresistance are complex and, as yet, inconclusive. Noncoding RNAs (ncRNAs), such as small nucleolar RNAs (snoRNAs), microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), represent transcripts without protein-coding potential. Accumulating evidence indicates that multiple deregulated ncRNAs, including miRNAs and lncRNAs, play pivotal roles in the development of chemoresistance in CRC. This notion has potential clinical implications.

Conclusions: In this review, we highlight the emerging roles and the regulatory mechanisms by which miRNAs and lncRNAs affect CRC chemoresistance. Tumor-specific miRNAs and lncRNAs may serve as novel therapeutic targets and prognostic biomarkers for CRC.