CircRNAs in hepatocellular carcinoma: characteristic, functions and clinical significance

Abstract

Hepatocellular carcinoma (HCC) is one of the most common and serious types of cancer worldwide, with high incidence and mortality rates. Circular RNAs (circRNAs) are a novel class of non-coding RNA with important biological functions. In recent years, multiple circRNAs have been found to be involved in the biological processes of tumorigenesis and tumor development. Increasing evidence has shown that circRNAs also play a crucial role in the occurrence and development of HCC. However, the specific molecular mechanism of circRNAs in HCC has not been fully elucidated. The present review systematically summarized the classification and basic characteristics of circRNAs, their biological functions and their role in the occurrence and development of HCC. By summarizing the previous studies on circRNAs in HCC, this study aimed to indicate potential approaches to improving the early diagnosis and treatment of HCC.

Keywords: circRNA-miRNA-mRNA axis; circRNAs; hepatocellular carcinoma; molecular sponge.

Figure 1

Formation of circRNA and linear RNA. (A) Exon-circRNA (EcircRNA): EcircRNAs are only derived from exons; (B) Circular intron RNA (CiRNA): CiRNAs are derived from intron lariats; (C) Exon-intron circRNA (EIciRNA): EIciRNA are derived from both exons and intron lariats; (D) Traditional linear mRNA comes from pre-mRNA classic splicing.

Figure 2

The functional mechanisms of circRNAs. (A) Acting as miRNA sponge; (B) Regulating transcription; (C) Regulating splicing of pre-mRNA; (D) Interacting with RBP; (E) Translated into protein/polypeptide.