Long non-coding RNA urothelial carcinoma associated1 induces cell replication by inhibiting BRG1 in 5637 cells.

YANBING GONG,LE WANG,BO JIN,JIANMING YANG,ZEBIN MAO,ZHENG ZHANG,XIUJUAN WANG,CHENGLIN WU

doi:10.3892/or.2014.3309

Abstract

Long non-coding RNA urothelial carcinoma associated 1 (UCA1) was first identified in bladder cancer tissues. High expression of UCA1 in bladder cancer has suggested it may serve as a potential diagnostic molecular marker for bladder cancer. Subsequent research in bladder cancer cell lines showed that UCA1 can promote cell proliferation, but the underlying mechanism remains unknown. In the present study, we identified BRG1 as a UCA1 binding partner using an in vitro RNA pull-down assay, and RNA-binding protein immunoprecipitation assay confirmed UCA1-BRG binding in bladder cancer cells in vivo. BRG1 is a chromatin remodeling factor with reported tumor suppressor activities that directly upregulates levels of the p21 cell cycle inhibitor by binding sequences in the p21 promoter. Depletion of UCA1 by RNAi resulted in upregulated p21 levels and inhibition of cell replication, while overexpressed UCA1 reduced p21 protein and promoted cell growth. Notably, UCA1 downregulation of p21 and induction of cell proliferation antagonized the function of BRG1. UCA1 highly expressed tissue samples are often with BRG1 high expression. Furthermore, we found that UCA1 impairs both binding of BRG1 to the p21 promoter and chromatin remodeling activity of BRG1. Collectively, these results demonstrate that UCA1 promotes bladder cancer cell proliferation by inhibiting BRG1.

Highlights

Over the last decade, genome-wide transcriptome studies have shown that the mammalian genome is abundantly transcribed and that at least 80% of this transcription is exclusively associated with long non-coding RNAs, which map to intronic and intergenic regions [1,2]
Based on previous studies indicating that urothelial carcinoma associated 1 (UCA1) exhibits tumorigenic activities, we first examined whether UCA1 promotes proliferation of 5637 cells
Cells were infected with lentiviruses harboring UCA1-shRNA or control‐shRNA under G418 selection for >1 week, and knockdown of UCA1 in UCA1-shRNA-transfected cells was confirmed by realtime PCR (Fig. 1A)

Summary

Introduction

Genome-wide transcriptome studies have shown that the mammalian genome is abundantly transcribed and that at least 80% of this transcription is exclusively associated with long non-coding RNAs (lncRNAs; >200 bp), which map to intronic and intergenic regions [1,2]. A growing body of evidence indicates that lncRNAs are important players in a wide range of biological processes, including chromatin remodeling, gene transcription, mRNA translation and protein function [4,5,6]. Previous studies have found that the mechanisms underlying gene regulation involve non-coding RNAs, including lncRNAs [7,8,9]. The study of lncRNA is still in its infancy [10,11], as only a small portion of lncRNAs has been examined for its biological activities and the molecular mechanisms of action have been characterized for very few lncRNAs

Methods

Results

Conclusion