Circular RNAs: A novel type of biomarker and genetic tools in cancer.

Yi-Neng Han,Jun-Hua Zheng,Yuan-Yuan Zhang,Wei Li,Sheng-Qiang Xia

doi:10.18632/oncotarget.18350

Abstract

Circular RNAs (circRNAs) are a novel type of universal and diverse endogenous noncoding RNAs (ncRNAs) and they form a covalently closed continuous loop without 5′ or 3′ tails unlike linear RNAs. Most circRNAs are presented with characteristics of abundance, stability, conservatism, and often exhibiting tissue/developmental-stage-specific expression. CircRNAs are generated either from exons or introns by back splicing or lariat introns. CircRNAs play important roles as miRNA sponges, gene transcription and expression regulators, RNA-binding protein (RBP) sponges and protein/peptide translators. Emerging evidence revealed the function of circRNAs in cancer and may potentially serve as a required novel biomarker and therapeutic target for cancer treatment. In this review, we discuss about the origins, characteristics and functions of circRNA and how they work as miRNA sponges, gene transcription and expression regulators, RBP sponges in cancer as well as current research methods of circRNAs, providing evidence for the significance of circRNAs in cancer diagnosis and clinical treatment.

Highlights

Over 70% of the human genome is found actively transcribed, but protein-coding genes only account for 1~2% of the human genome, whereas the vast majority of transcripts are noncoding RNAs [1]. ncRNA can be divided into two major groups, including housekeeper ncRNAs, namely ribosomal RNA, transfer RNA, small nuclear RNA and small nucleolar RNA, as well as regulatory ncRNAs
Based on the function as miRNA sponges, translation and expression regulators and RNA-binding protein (RBP) sponges, circRNAs play an important role in cancer and we talk about current research methods of circRNAs in cancer, providing evidence for the significance of circRNAs in cancer diagnosis and clinical treatment
The functions of circRNAs as miRNA sponges, transcriptional regulators and RBP sponges are increasingly recognized and the roles of circRNAs in biogenesis and functional mechanisms in numerous diseases including cancers are becoming the focus of study

Summary

Introduction

Over 70% of the human genome is found actively transcribed, but protein-coding genes only account for 1~2% of the human genome, whereas the vast majority of transcripts are noncoding RNAs (ncRNAs) [1]. ncRNA can be divided into two major groups, including housekeeper ncRNAs, namely ribosomal RNA (rRNA), transfer RNA (tRNA), small nuclear RNA (snRNA) and small nucleolar RNA (snoRNA), as well as regulatory ncRNAs. CircRNAs play important roles as miRNA sponges, gene transcription and expression regulators, RNA-binding protein (RBP) sponges and protein/peptide translators.

Results

Conclusion