CircEVI5 acts as a miR-4793-3p sponge to suppress the proliferation of gastric cancer

Meinan Yan,Hui Li,Yuan Yao,Jing Liu,Liling Niu

doi:10.1038/s41419-021-04061-4

Abstract

Circular RNAs (circRNAs) are a novel class of endogenous noncoding RNAs (ncRNAs) with a covalently closed loop structure. Accumulating evidence shows that circRNAs play vital roles in the growth, metastasis, treatment and prognosis of various cancers. However, the detailed functions and underlying mechanisms of circEVI5 (hsa_circ_0013162) in gastric cancer (GC) remain undocumented. In this study, the expression levels and prognostic value of circEVI5 were validated in GC tissue samples by using qRT-PCR. circEVI5 was significantly downregulated in GC tissues and cells, and low circEVI5 expression was correlated with poor prognosis. Next, in vitro CCK-8 assay, EdU incorporation assay, PI staining cell cycle assay, and in vivo xenograft mouse models were conducted to assess the functions of circEVI5. Gain of function experiments indicated that circEVI5 could inhibit GC cell proliferation and retard the cell cycle. Moreover, bioinformatics prediction showed that circEVI5 binds to miR-4793-3p, while FOXO1 may be a target of miR-4793-3p. Pull-down assays, RNA immunoprecipitation (RIP) assays, luciferase assays, and western blot were used to confirm the interactions between circEVI5, miR-4793-3p, and FOXO1. Functional assays demonstrated that circEVI5 suppressed the proliferation of GC by sponging miR-4793-3p and increasing FOXO1 expression levels. In conclusion, our study demonstrated that circEVI5 can bind miR-4793-3p as a ceRNA to eliminate the negative regulation of FOXO1, therefore suppressing GC proliferation.

Highlights

Gastric cancer is still a major threat to human health [1]
We explored the role of circEVI5 in the development and progression of gastric cancer (GC). circEVI5 was significantly downregulated in GC tissues as well as GC cell lines, and low circEVI5 expression was correlated with poor prognosis. circEVI5 could act as a sponge of miR-4793-3p to regulate the
RESULTS circEVI5 is downregulated in gastric cancer, and low circEVI5 expression correlates with poor prognosis circEVI5 is derived from exon 2, 3, and 4 regions within the EVi5 locus, which is located on chromosome 1p22, and the spliced length is 339 bp

Summary

Introduction

Gastric cancer is still a major threat to human health [1]. Based on global cancer statistics [2], GC is the fifth most diagnosed malignancy and the fourth most common cause of cancerrelated death in the world, and it is necessary to explore GCspecific biomarkers and underlying molecular mechanisms to improve diagnosis and therapies.CircRNAs are a new subgroup of ncRNAs. C qRT-PCR analysis of circEVI5 expression in SNU-1 and MKN-45 cells treated with or without RNase R. As indicated by the functional experimental results, the viability of SNU-1 and MKN-45 cells with overexpressed circEVI5 was significantly inhibited (Fig. 2C).

Results

Conclusion