MicroRNA-202-3p Inhibits Cell Proliferation by Targeting ADP-Ribosylation Factor-like 5A in Human Colorectal Carcinoma

Qifeng Wang,Qinghua Xu,Dan Huang,Weijie Guo,Shujuan Ni,Lisha Wang,Cong Tan,Ruopeng Zha,Xianghuo He,Xiang Du,Zhaohui Huang,Weiqi Sheng,Xiuying Xiao,Jiwei Zhang

doi:10.1158/1078-0432.ccr-13-1023

Abstract

MicroRNAs (miRNA) that are strongly implicated in carcinogenesis have recently reshaped our understanding of the role of non-protein-coding RNAs. Here, we focused on the function and molecular mechanism of miR-202-3p and its potential clinical application in colorectal cancer. miR-202-3p expression was determined by quantitative reverse transcriptase PCR (qRT-PCR) in 94 colorectal cancer tissues and corresponding noncancerous tissues (NCT). Cell proliferation and colony formation assays in vitro and xenograft experiments in vivo were used to evaluate the effect of miR-202-3p on colorectal cancer cell proliferation. Luciferase assay and Western blot analysis were performed to validate the potential targets of miR-202-3p after the preliminary screening by online prediction and microarray analysis. The mRNA and protein levels of target genes were detected by qRT-PCR and immunohistochemical staining. The copy number of pre-miR-202 was measured by quantitative PCR. First, miR-202-3p was significantly downregulated in 46.7% colorectal cancer samples compared with NCTs. The overexpression of miR-202-3p inhibited colorectal cancer cell growth in vitro and repressed tumorigenesis in nude mice. Then, miR-202-3p downregulated ADP-ribosylation factor-like 5A (ARL5A) protein level by binding to its 3' untranslated region, and knockdown of ARL5A phenocopied the proliferation inhibition effect of miR-202-3p. Furthermore, both of ARL5A mRNA and protein levels were upregulated in colorectal cancer samples compared with NCTs and high ARL5A protein levels predicted a poor prognosis. miR-202-3p might function as a tumor suppressor in colorectal cancer, and ARL5A, the functional target of miR-202-3p in colorectal cancer, is a potential prognostic factor for colorectal cancer.

Highlights

MicroRNAs are small noncoding RNAs (18–22 nt in length) that regulate the expression of target genes at Authors' Affiliations: 1Department of Pathology; 2bioMerieux Laboratory, Fudan University Shanghai Cancer Center; 3Department of Oncology, Shanghai Medical College; 4Institute of Pathology; 5Institutes of Biomedical Sciences, Fudan University, Shanghai; 6Wuxi Oncology Institute, the Affiliated Hospital of Jiangnan University, Wuxi; 7State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Shanghai Jiao Tong University School of Medicine; and 8Department of Oncology, Ren Ji Hospital, Shanghai Jiao Tong University, Shanghai, ChinaNote: Supplementary data for this article are available at Clinical Cancer Research Online.Q
First, miR-202-3p was significantly downregulated in 46.7% colorectal cancer samples compared with noncancerous tissues (NCT)
MiR-202-3p downregulated ADP-ribosylation factor-like 5A (ARL5A) protein level by binding to its 30 untranslated region, and knockdown of ARL5A phenocopied the proliferation inhibition effect of miR-202-3p. Both of ARL5A mRNA and protein levels were upregulated in colorectal cancer samples compared with NCTs and high ARL5A protein levels predicted a poor prognosis

Summary

Introduction

MicroRNAs (miRNA) are small noncoding RNAs (18–22 nt in length) that regulate the expression of target genes at Authors' Affiliations: 1Department of Pathology; 2bioMerieux Laboratory, Fudan University Shanghai Cancer Center; 3Department of Oncology, Shanghai Medical College; 4Institute of Pathology; 5Institutes of Biomedical Sciences, Fudan University, Shanghai; 6Wuxi Oncology Institute, the Affiliated Hospital of Jiangnan University, Wuxi; 7State Key Laboratory of Oncogenes and Related Genes, Shanghai Cancer Institute, Shanghai Jiao Tong University School of Medicine; and 8Department of Oncology, Ren Ji Hospital, Shanghai Jiao Tong University, Shanghai, ChinaNote: Supplementary data for this article are available at Clinical Cancer Research Online (http://clincancerres.aacrjournals.org/).Q. Note: Supplementary data for this article are available at Clinical Cancer Research Online (http://clincancerres.aacrjournals.org/). The posttranscriptional level by binding to their target mRNAs [1, 2]. Since their discovery in 1993, the number of verified miRNAs has grown rapidly, and the latest version of miRBase Org/) has annotated 2,578 mature miRNA sequences in the human genome. MiRNAs are estimated to regulate up to one third of human genes at the posttranscriptional level [3]. MiRNAs have been reported to be involved in human cancers, their biologic functions and molecular mechanisms remain largely unknown

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