About this Research Topic
Circular RNAs (circRNAs) were found a decade ago as a new class of non-coding RNAs. CircRNAs are generally generated by alternative splicing of pre-mRNA, in which the ends of a single or several adjacent exons are jointed in a covalently closed and circular way in a process known as “backsplicing or circular splicing.” CircRNAs exist in the cytoplasm with remarkable stability (due to the lack of 5’ and 3’ ends), exhibit cell type-specific expression and conservation between different species (mouse vs. human). CircRNAs vary across a variety of human tissues and are not correlated with the expression of linear canonical mRNA. However, the ratio between circular and linear mRNA is cell-specific.
Comparing with the genes coding for proteins, non-coding RNAs may regulate gene expression during transcription, post-transcription, translation, and post-translation, protein binding, and microRNA sponging. CircRNAs have been reported to be significantly dysregulated in cancer tissues versus the adjacent tissues. CircRNAs have been revealed to recruit and reprogram key components involved in the tumor microenvironment (TME), and mediate various signaling pathways, thus affecting tumorigenesis, angiogenesis, immune response, and metastatic progression. CircRNAs play a role in various tumors, including breast cancer, lung adenocarcinoma, esophageal squamous cell carcinoma, gastric cancer, hepatocellular carcinoma, colorectal cancer, osteosarcoma, renal cancer, bladder cancer, and glioma. CircRNAs regulate cancer via both protein binding and microRNA sponging. Most of the CircRNAs are not translated, while certain endogenous circRNAs appear to code for proteins to regulated cancer cells. The abundance of circRNAs than linear mRNA due to its high stability indicates that it may serve as novel biomarkers for cancer diagnosis and prognosis and potential therapeutic targets.
This Research Topic aims to gather Original Research, Brief Research Report, Methods, Reviews/Mini-Reviews articles discussing the biological function of circRNAs in cancer. The following topics are welcome:
• Techniques to identify and characterize circRNAs
• CircRNAs expression and regulation
• Different pathways regulated by circRNAs/circRNAs as regulators of tumor progression
• The relationship among circRNAs and other non-coding RNA, such as microRNA (miRNA) and Linear long non-coding RNA (lncRNA)
• The evidence for certain endogenous circRNAs coding for proteins
Keywords: Circular RNA, Splicing, Cancer, Non-coding RNA, Gene Regulation
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