Cancer Stem Cells and Regulatory RNAs Crosstalk: Fostering Possibilities for Cancer Therapies

Cancer stem cells (CSCs) have been reported to be responsible for tumor initiation, therapy resistance, progression, relapse, and metastasis. Despite their potential clinical importance, their mode of regulation at the molecular level is poorly understood. This is somewhat because of substantial variation of the CSC phenotype between patients and functional heterogeneity in tumors harboring genetically distinct CSCs. Regulatory noncoding RNAs (rncRNAs) are emerging as new players in the CSC paradigm. They contribute to maintaining the CSC niche. Here, we discuss rncRNAs that are associated or likely to have an association with CSCs and that control the genetic program that specifies CSC identity and properties. These rncRNAs are also involved in the epigenetic modification of these cells. Moreover, CSC-specific oncogenic and tumor suppressor rncRNAs may serve as novel therapeutic targets, which suggest their potential importance in clinical decisionmaking. Their study will further facilitate the discovery of RNA-based novel therapies and therapeutic targets specific to CSCs.