CircCDYL Acts as a Tumor Suppressor in Wilms' Tumor by Targeting miR-145-5p.

Rui Zhou,Tianxin Zhao,Xiaofeng Gao,Wen Fu,Fuming Deng,Zhongmin Li,Kai Fu,Wei Jia,Guochang Liu

doi:10.3389/fcell.2021.668947

Rui Zhou, Tianxin Zhao + Show 7 more

Open Access

https://doi.org/10.3389/fcell.2021.668947

Copy DOI

Abstract

Circular RNAs (circRNA) have been reported to exert evident functions in many human carcinomas. However, the possible mechanisms concerning the circRNA in various tumors are still elusive. In this research, we analyzed the expression profile and biological functions of circular RNA CDYL (circCDYL, circBase ID: hsa_circ_0008285) in Wilms’ tumor. Here, miRNA and gene expression were examined by real-time PCR in Wilms’ tumor tissues and cell lines. The functions of circCDYL and its potential targets to influence cell proliferation, migration, and invasion in Wilms’ tumor cells were determined by biological functional experiments in vitro and in vivo. We predicted and analyzed potential miRNA targets through online bioinformatic tools. To validate the interactions between circCDYL and its targets, we performed RNA fluorescence in situ hybridization, biotin-coupled miRNA capture assay, and biotin-coupled probe pull-down assay. Tight junction protein l (TJP1) was proved to be the target gene of the predicted miRNA by dual-luciferase reporter assay. The expression level of TJP1 in Wilms’ tumor cells was identified via Western blot. We showed that circCDYL was downregulated in WT tissue compared with adjacent non-tumor tissue. Upregulation of circCDYL could reduce cell proliferation, migration, and invasion. Mechanically, circCDYL, functioning as a miRNA sponge, decreased the expression level of miR-145-5p and TJP1 3′UTR was validated as the target of miR-145-5p, facilitating the circCDYL/miR-145-5p/TJP1 axis. In conclusion, our study suggested circCDYL as a novel biomarker and therapeutic target for WT treatment.

Highlights

Wilms’ tumor (WT, nephroblastoma) accounts for about 6% of childhood tumors and for 95% of pediatric kidney tumors, ranking the fifth in childhood malignancy
The circCDYL expression was significantly downregulated in five WT samples compared with adjacent non-tumor tissues from the results of circular RNA (circRNA) deep sequencing (Figure 1A)
By using the separation of nuclear and cytoplasmic RNA isolation, we demonstrated that circCDYL predominately localized in the cytoplasm in both SK-NEP-1 and G401 cell lines (Figures 1D,E)

Summary

Introduction

Wilms’ tumor (WT, nephroblastoma) accounts for about 6% of childhood tumors and for 95% of pediatric kidney tumors, ranking the fifth in childhood malignancy. Most WT develop before the age of 3 years (Wang et al, 2012). With the improvement of comprehensive therapy combining surgery, chemotherapy, and radiotherapy, Abbreviations: circRNA, circular RNA; miRNA, microRNA; RIP, RNA immunoprecipitation; TJP1, tight junction protein 1; FISH, fluorescence in situ hybridization; WT, Wilms’ tumor. CircCDYL Suppressed Wilms’ Tumor nearly 85% of WT children were cured, a few children still died because of recurrence, metastasis, resistance to chemotherapy, and other complicated factors. Due to continuous research of WT in recent years, people have gained a better understanding of the pathogenesis of WT, but there are still many issues that deserve further discussion

Methods

Results

Conclusion