The role of circRNAs in cancers.

Ling-Ping Zhu,Xiu Chen,He-Da Zhang,Jia-Hua Hu,Jin-Hai Tang,Su-Jin Yang,Yun-Jie He,Jun-Chen Hou,Si-Ying Zhou,Jian-Hua Zhao,Shan-Liang Zhong,Jian Li

doi:10.1042/bsr20170750

Abstract

Circular RNAs (circRNAs) are recently regarded as a naturally forming family of widespread and diverse endogenous noncoding RNAs (ncRNAs) that may regulate gene expression in mammals. At present, above 30000 circRNAs have already been found, with their unique structures to maintain stability more easily than linear RNAs. Several previous literatures stressed on the important role of circRNAs, whose expression was relatively correlated with patients’ clinical characteristics and grade, in the carcinogenesis of cancer. CircRNAs are involved in many regulatory bioprocesses of malignance, including cell cycle, tumorigenesis, invasion, metastasis, apoptosis, vascularization, through adsorbing RNA as a sponge, binding to RNA-binding protein (RBP), modulating transcription, or influencing translation. Therefore, it is inevitable to further study the interactions between circRNAs and tumors and to develop novel circRNAs as molecular markers or potential targets, which will provide promising applications in early diagnosis, therapeutic evaluation, prognosis prediction of tumors and even gene therapy for tumors.

Highlights

Besides the conventional coding mRNA, tRNA, and rRNAs, there is a tremendous diversity of noncoding attached RNA genres which exist in the cells, such as miRNAs, lncRNAs, piRNAs, siRNAs, tmRNAs, sRNAs, tiRNAs, eRNAs, snoRNAs, snRNAs, and other noncoding RNAs
We hypothesized that hsa circ 0067934 could promote the proliferation of ECSS cells by regulating the cell cycle [60]. Another circular RNA (circRNA) named cir-itchy E3 ubiquitin protein ligase (ITCH), acquired from a total of 684 esophageal squamous cell carcinoma (ESCC) and paired adjacent nontumor tissue samples via RT-PCR, which could act as a sponge for miR-7, miR-17, and miR-214, had an inhibitory effect on ESCC by stimulating ITCH levels to promote an ubiquitin-mediated dishevelled segment polarity protein 2 (Dvl2) degradation, suppressing the canonical Wnt/β-catenin [61]. These results indicate that hsa circ 0067934 may work as an emerging potential tumor marker and therapeutic target of ESCC and cir-ITCH can inhibit the evolution of ESCC by regulating the Wnt pathway
The functions of most circRNAs are largely unclear, existing evidence has shown that circRNAs function in multiple biological processes, such as miRNA binding, RNA-binding protein (RBP) binding, and regulation of transcription or splicing

Summary

Introduction

Besides the conventional coding mRNA, tRNA, and rRNAs, there is a tremendous diversity of noncoding attached RNA genres which exist in the cells, such as miRNAs, lncRNAs, piRNAs, siRNAs, tmRNAs, sRNAs, tiRNAs, eRNAs, snoRNAs, snRNAs, and other noncoding RNAs (ncRNAs). The exonic circRNAs predominantly remain in c 2017 The Author(s) CircRNAs are involved in transcription, translation, splicing, c 2017 The Author(s) Some studies have reported that circRNAs were concerned with many kinds of human diseases, and were widely involved in numerous physiological and pathological processes, for instance promoting insulin biosynthesis c 2017 The Author(s)

Conclusion and perspective

Ethical approval