Mechanistic Role of circRNAs in Malignant Characterizations of Cancer Stem Cells

Cancer stem cells (CSCs) are a type of cancer cells in tumor tissues with highly malignant characterizations, including self-renewal, migration, invasion, metastasis and drug/radio therapy resistance. Numerous regulatory RNAs such as circular RNAs (circRNAs) are deregulated in CSCs and involved in stemness properties of these types of cancer cells. Due to the high stability and the half-life, circRNAs provide a significant clinical benefit for their use as diagnostic and therapeutic biomarkers. CircRNAs interact with specific miRNAs, proteins, and DNA regions, and thus can regulate various cellular functions and signaling pathways involved in the diverse biological, physiological, cellular, and pathophysiological processes. This review introduces CSCs and their associated markers. Also, it provides an overview of the biogenesis of circRNAs and emphasizes on the oncogenic and suppressive roles of circRNAs in different types of CSCs. Also, it highlights the mechanistic roles of circRNAs as miRNA sponger or/and protein decoy in this type of cancer cells. Understanding how circRNAs affect cellular processes at a molecular level holds significant potential for both diagnostic and therapeutic approaches in cancer treatment.