Non-coding RNAs in Cancer and Cancer Stem Cells

Abstract

Cancer stem cells (CSCs) have been identified in various types of human tumors. CSCs share a variety of signaling pathways with normal somatic stem cells, including those involved in self-renewal, differentiation, and the regulation of specific gene expression. Although the properties of CSCs, such as tumorigenicity and resistance to conventional therapeutics, have been the focus of intensive research in the field of cancer, the molecular mechanisms underlying the regulation of CSC properties remain incompletely understood. Therefore, many cancer researchers have investigated protein-coding genes and products, including surface markers that are involved in the acquisition of CSC properties. Recently, in addition to alterations in protein-coding genes, aberrant expression of non-coding RNAs such as microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) that play an important role in cellular, physiological, and developmental processes have been observed in various diseases including cancers. These non-coding RNAs also play important roles in the regulation of CSC properties. Several non-coding RNAs that regulate CSC properties have been identified; therefore, a better understanding of the mechanisms underlying such regulation could contribute to the identification of promising biomarkers and therapeutic targets. In this chapter, we discuss the general features of CSCs and the roles of non-coding RNAs, especially miRNAs and lncRNAs, in the regulation of CSC properties, and we summarize the current therapeutic strategies aimed at regulating non-coding RNAs for the purpose of CSC therapy.