Gao YE, Wang Y, Chen FQ, Feng JY, Yang G, Feng GX, Yang Z, Ye LH, Zhang XD. Post-transcriptional modulation of protein phosphatase PPP2CA and tumor suppressor PTEN by endogenous siRNA cleaved from hairpin within PTEN mRNA 3'UTR in human liver cells.
Acta Pharmacol Sin 2016;
37:898-907. [PMID:
27133296 PMCID:
PMC4933753 DOI:
10.1038/aps.2016.18]
[Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 03/03/2016] [Indexed: 01/08/2023] Open
Abstract
Aim:
Increasing evidence shows that mRNAs exert regulatory function along with coding proteins. Recently we report that a hairpin within YAP mRNA 3′UTR can modulate the Hippo signaling pathway. PTEN is a tumor suppressor, and is mutated in human cancers. In this study we examined whether PTEN mRNA 3′UTR contained a hairpin structure that could regulate gene regulation at the post-transcriptional level.
Methods:
The secondary structure of PTEN mRNA 3′UTR was analyzed using RNAdraw and RNAstructure. Function of hairpin structure derived from the PTEN mRNA 3′UTR was examined using luciferase reporter assay, RT-PCR and Western blotting. RNA-immunoprecipitation (RIP) assay was used to analyze the interaction between PTEN mRNA and microprocessor Drosha and DGCR8. Endogenous siRNA (esiRNA) derived from PTEN mRNA 3′UTR was identified by RT-PCR and rt-PCR, and its target genes were predicted using RNAhybrid.
Results:
A bioinformatics analysis revealed that PTEN mRNA contained a hairpin structure (termed PTEN-sh) within 3′UTR, which markedly increased the reporter activities of AP-1 and NF-κB in 293T cells. Moreover, treatment with PTEN-sh (1 and 2 μg) dose-dependently inhibited the expression of PTEN in human liver L-O2 cells. RIP assay demonstrated that the microprocessor Drosha and DGCR8 was bound to PTEN-sh in L-O2 cells, leading to the cleavage of PTEN-sh from PTEN mRNA 3′UTR. In addition, microprocessor Dicer was involved in the processing of PTEN-sh. Interestingly, esiRNA (termed PTEN-sh-3p21) cleaved from PTEN-sh was identified in 293T cells and human liver tissues, which was found to target the mRNA 3′UTRs of protein phosphatase PPP2CA and PTEN in L-O2 cells. Treatment of L-O2 or Chang liver cells with PTEN-sh-3p21 (50, 100 nmol/L) promoted the cell proliferation in dose- and time-dependent manners.
Conclusion:
The endogenous siRNA (PTEN-sh-3p21) cleaved from PTEN-sh within PTEN mRNA 3′UTR modulates PPP2CA and PTEN at the post-transcriptional level in liver cells.
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