Cellular nucleic acid binding protein suppresses tumor cell metastasis and induces tumor cell death by downregulating heterogeneous ribonucleoprotein K in fibrosarcoma cells.

Abstract

BACKGROUND:

Cellular nucleic acid binding protein (CNBP) has been implicated in vertebrate craniofacial development and in myotonic dystrophy type 2 (DM2) and sporadic inclusion body myositis (sIBM) human diseases by controlling cell proliferation and survival to mediate neural crest expansion. CNBP has been found to bind single-stranded nucleic acid and promote rearrangements of nucleic acid secondary structure in an ATP-independent manner, acting as a nucleic acid chaperone.

METHODS:

A variety of methods were used, including cell viability assays, wound-scratch assays, chemotaxis assays, invasion assays, circular dichroic (CD) spectroscopy, NMR spectroscopy, chromatin immunoprecipitation, expression and purification of recombinant human CNBP, electrophoretic mobility shift assay (EMSA), surface plasmon resonance (SPR), fluorescence resonance energy transfer (FRET) analyses, luciferase reporter assay, Western blotting, and isothermal titration calorimetry (ITC).

RESULTS:

Up-regulation of CNBP induced human fibrosarcoma cell death and suppressed fibrosarcoma cell motility and invasiveness. It was found that CNBP transcriptionally down-regulated the expression of heterogeneous ribonucleoprotein K (hnRNP K) through its conversion of a G-rich sequence into G-quadruplex in the promoter of hnRNP K. G-quadruplex stabilizing ligand tetra-(N-methyl-4-pyridyl) porphyrin (TMPyP4) could interact with and stabilize the G-quadruplex, resulting in downregulation of hnRNP K transcription.

CONCLUSIONS:

CNBP overexpression caused increase of cell death and suppression of cell metastasis through its induction of G-quadruplex formation in the promoter of hnRNP K resulting in hnRNP K down-regulation.

GENERAL SIGNIFICANCE:

The present result provided a new solution for controlling hnRNP K expression, which should shed light on new anticancer drug design and development.

• Authors: Jun Qiu, Siqi Chen, Lijuan Su, Jinggong Liu, Nannan Xiao, Tian-Miao Ou, Jia-Heng Tan, Lian-Quan Gu, Zhi-Shu Huang, Ding Li
• Journal: Biochimica et biophysica acta (Biochim Biophys Acta) Vol. 1840 Issue 7 Pg. 2244-52 (Jul 2014) ISSN: 0006-3002 [Print] Netherlands
• PMID: 24594223 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2014 Elsevier B.V. All rights reserved.

Chemical References

• CNBP protein, human
• Heterogeneous-Nuclear Ribonucleoprotein K
• Nucleic Acids
• RNA-Binding Proteins

Topics

• Cell Death (genetics)
• Cell Line, Tumor
• Cell Survival (genetics)
• Chromatin Immunoprecipitation
• Fibrosarcoma (genetics, pathology)
• Fluorescence Resonance Energy Transfer
• G-Quadruplexes
• Gene Expression Regulation, Neoplastic (genetics)
• Heterogeneous-Nuclear Ribonucleoprotein K (biosynthesis, genetics)
• Humans
• Neoplasm Metastasis
• Nucleic Acids (genetics)
• Promoter Regions, Genetic
• RNA-Binding Proteins (genetics, metabolism)