RNA-binding protein PCBP2 modulates glioma growth by regulating FHL3
Wei Han, … , Boqin Qiang, Xiaozhong Peng
Wei Han, … , Boqin Qiang, Xiaozhong Peng
Published April 15, 2013
Citation Information: J Clin Invest. 2013;123(5):2103-2118. https://doi.org/10.1172/JCI61820.
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Research Article Oncology

RNA-binding protein PCBP2 modulates glioma growth by regulating FHL3

Abstract

PCBP2 is a member of the poly(C)-binding protein (PCBP) family, which plays an important role in posttranscriptional and translational regulation by interacting with single-stranded poly(C) motifs in target mRNAs. Several PCBP family members have been reported to be involved in human malignancies. Here, we show that PCBP2 is upregulated in human glioma tissues and cell lines. Knockdown of PCBP2 inhibited glioma growth in vitro and in vivo through inhibition of cell-cycle progression and induction of caspase-3–mediated apoptosis. Thirty-five mRNAs were identified as putative PCBP2 targets/interactors using RIP-ChIP protein-RNA interaction arrays in a human glioma cell line, T98G. Four-and-a-half LIM domain 3 (FHL3) mRNA was downregulated in human gliomas and was identified as a PCBP2 target. Knockdown of PCBP2 enhanced the expression of FHL3 by stabilizing its mRNA. Overexpression of FHL3 attenuated cell growth and induced apoptosis. This study establishes a link between PCBP2 and FHL3 proteins and identifies a new pathway for regulating glioma progression.

Authors

Wei Han, Zhongshuai Xin, Zhiqiang Zhao, Wen Bao, Xihua Lin, Bin Yin, Jizong Zhao, Jiangang Yuan, Boqin Qiang, Xiaozhong Peng

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Figure 5

Binding of biotin-labeled candidate mRNAs to PCBP2.

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Binding of biotin-labeled candidate mRNAs to PCBP2. (A) Schematic of the...
(A) Schematic of the 8 indicated candidate mRNAs. The specific fragments used as templates for the synthesis of biotin-labeled RNAs are indicated with underlines, and the nucleotide positions amplified by PCR are shown. (B) Biotin pull-down analysis of complexes formed in vitro using biotin-labeled candidate mRNA segments (shown in A) and T98G whole-cell lysates. The α-globin-3′ UTR and a nonsense sequence were included as the positive and negative controls, respectively. (C) A specific association between PCBP2 and its candidate target mRNAs (identified in B) was confirmed by a competition assay. Five- or 10-fold excess of unlabeled RNA was added to compete with the biotin-labeled RNA for interaction with PCBP2, and 2- or 3-fold excess of cell lysates was incubated with biotin-labeled RNA. (D) Detection of the binding affinities of the target mRNAs to PCBP2 by biotin pull-down analysis using all of the biotin-labeled RNAs identified above.