Circular RNAs and their roles in head and neck cancers

Abstract

Circular RNAs are abundant endogenous non-coding RNA with no 5′ cap and 3′ polyadenylation tail that modify liner mRNAs and have no terminal structures. Our knowledge of the biogenesis of circular RNAs has been expanded, and circular RNAs were shown to be key regulators of various diseases, especially cancers. Head and neck cancers are the sixth most popular cancers worldwide, and the overall survival rates remain unsatisfactory. Recent studies have indicated that circular RNAs are involved in the tumorigenesis, progression, invasion and chemosensitivity of head and neck cancers and that some circular RNAs could serve as diagnostic and prognostic biomarkers. In this study, we summarize research advances in the regulation of circular RNA biogenesis, their characteristics and functions, the involvement of circular RNAs in the pathophysiology of head and neck cancers and their potential clinical utilization, as well as the likely directions of future studies.

<p>Diagnostic Significance of Downregulated circMORC3 as a Molecular Biomarker of Hypopharyngeal Squamous Cell Carcinoma: A Pilot Study</p>

“…CircRNAs exist widely in various tissues and in saliva and plasma, which allows for non-invasive diagnosis with dysregulated circRNAs. 12 Here, we validated the downregulation of circMORC3 in HSCC tissues compared to paired normal tissues, which was consistent with the previous microarray results. 32 Further analyses of the relationships between circMORC3 expression levels and clinicopathological features illustrated that the expression levels of circMORC3 were more significantly decreased in HSCC with higher T stages and bigger tumor sizes than those with lower T stages and smaller tumor sizes.…”

“…31 CircRNAs could also affect physiopathologic processes by binding to RNA binding proteins or regulating transcription and splicing. 12 CircRNAs are extremely stable compared to linear RNAs because they lack free 3′ or 5′ ends. CircRNAs exist widely in various tissues and in saliva and plasma, which allows for non-invasive diagnosis with dysregulated circRNAs.…”

“…[9][10][11] Thus, circRNAs are ideal molecular biomarkers for various diseases, including diverse cancers of the aerodigestive tract. [12][13][14] For example, hsa_circ_00001649, hsa_circ_0000745 and hsa_circ_0000140 were suggested to be novel biomarkers for gastric cancer, [15][16][17] and hsa_-circ_0001946, hsa_circ_0043603 18 and hsa_circ_0067934 19 could serve as biomarkers for esophageal squamous cell carcinoma. At the same time, the clinical application potential of hsa_circ_0000711 and hsa_circ_0004585 as biomarkers for colorectal cancer was demonstrated.…”

circIGHG-Induced Epithelial-to-Mesenchymal Transition Promotes Oral Squamous Cell Carcinoma Progression via miR-142-5p/IGF2BP3 Signaling

“…Thanks to advance in RNA profiling, floras of circRNAs have been identified in multiple cancers (28)(29)(30). To date, nonetheless, rare circRNAs have been associated to OSCC, the most commonly occurring malignancy in head and neck tumors (31,32). Besides, how circRNAs influence the development and metastasis of OSCC still needs to be further detailed.…”

circRNA_0000140 suppresses oral squamous cell carcinoma growth and metastasis by targeting miR-31 to inhibit Hippo signaling pathway

“…Recent studies showed great potential of circRNAs as promising clinical biomarkers and therapeutic targets for cancers. Moreover, the involvement of the circRNA-miRNA-mRNA signaling axis in OSCC development and progression has been established 16 . Of note, hsa_-circ_0008309 inhibits miR-136-5p and miR-382-5p expression and augments ATXN1 expression in OSCC 17 .…”