J Exp Clin Cancer Res. 2016 Sep 17;35(1):145. doi: 10.1186/s13046-016-0423-y.

Demystifying the mechanistic and functional aspects of p21 gene activation with double-stranded RNAs in human cancer cells.

Wu HL1, Li SM2,3, Hu J4,5, Yu X2,3, Xu H2,3, Chen Z2,3, Ye ZQ2,3.

Author information

1Department of Geriatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People’s Republic of China.2Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Liberalization Avenue, No. 1095, Wuhan, 430030, People’s Republic of China.3Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People’s Republic of China.4Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Liberalization Avenue, No. 1095, Wuhan, 430030, People’s Republic of China. jiahutjm@163.com.5Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, People’s Republic of China. jiahutjm@163.com.

Abstract

BACKGROUND:

The recently identified phenomenon of double-stranded RNA (dsRNA)-mediated gene activation (RNAa) has been studied extensively, as it is present in humans, mice, and Caenorhabditis elegans, suggesting that dsRNA-mediated RNAa is an evolutionarily conserved mechanism. Previous studies have shown that dsP21-322 can induce tumor suppressor gene p21 expression in several human cancer cells. Nonetheless, the role of dsRNAs in the activation of gene expression, including their target molecules and associated key factors, remains poorly understood.

METHODS:

Oligonucleotides were used to overexpress dsRNAs and dsControl. Real-time PCR and Western blotting were used to detect corresponding mRNA and protein expression, respectively. Fluorescence microscopy was used to examine the kinetics of dsRNA subcellular distribution. Luciferase reporter assays were performed to verify dsRNA target molecules. Chromatin immunoprecipitation (ChIP) assays were carried out to determine whether histone modification and other associated key factors are involved in saRNA-mediated p21 expression.

RESULTS:

We demonstrated that dsRNA-mediated p21 induction in human cell lines is a common phenomenon. This process occurs at the transcriptional level, and the complementary p21 promoter is the intended dsRNA target. Additionally, ChIP assays indicated that p21 activation was accompanied by an increased enrichment of AGO1 and the trimethylation of histone H3K4 at dsRNA-targeted genomic sites.

CONCLUSION:

These data systematically reveal the mechanistic and functional aspects of ncRNA-mediated p21 activation in human cancer cells, which may be a useful tool to analyze gene function and aid in the development of novel drug targets for cancer therapeutics.

KEYWORDS:

Functional features; Promoter-targeted; RNAa; p21; saRNA

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