Functional Roles and Biological Mechanisms of Circular RNAs and Their Encoded Peptides in Glioma: A Narrative Review

Circular RNAs (circRNAs) are a complicated class of non-coding RNAs that have a covalently closed loop structure and are very stable and cautious. Multiple biological processes of malignancy, including tumorigenesis, development, invasion, metastasis, apoptosis, and vascularization, are disrupted by an increased number of circRNAs. Recent research has showed that circRNAs, functioning as microRNA (miRNA) sponges or protein scaffolds, interacting with RNA-binding proteins (RBPs), and autophagy regulators, affect the transcription and splicing regulation. Many circRNAs have tissue-specific expression patterns and are heavily conserved. CircRNA levels in neurons are dynamically modulated. Growing evidence suggests that circRNAs are highly abundant in neural tissues, perhaps owing to the proliferation of particular genes that promote circularization, implying that circRNA dysregulation is linked to nervous system disorders including glioma. The most widespread and deadly primary malignant brain tumor is glioma. CircRNA has a close connection to glioma, according to reported research. Here, the current knowledge about the properties of circRNAs is introduced and the biological and molecular functions of circRNAs are described. Then, the clinical association of circRNAs with glioma/glioblastoma and their level of expression and their regulatory mechanisms in tumorigenesis are discussed. Moreover, the potential of circRNAs as diagnostic biomarkers and predictors of brain cancer risk and possible therapeutic targets in medicine is examined.