The microRNA-302b-inhibited insulin-like growth factor-binding protein 2 signaling pathway induces glioma cell apoptosis by targeting nuclear factor IA

PLoS One. 2017 Mar 21;12(3):e0173890. doi: 10.1371/journal.pone.0173890. eCollection 2017.

Abstract

MicroRNAs are small noncoding RNAs that post-transcriptionally control the expression of genes involved in glioblastoma multiforme (GBM) development. Although miR-302b functions as a tumor suppressor, its role in GBM is still unclear. Therefore, this study comprehensively explored the roles of miR-302b-mediated gene networks in GBM cell death. We found that miR-302b levels were significantly higher in primary astrocytes than in GBM cell lines. miR-302b overexpression dose dependently reduced U87-MG cell viability and induced apoptosis through caspase-3 activation and poly(ADP ribose) polymerase degradation. A transcriptome microarray revealed 150 downregulated genes and 380 upregulated genes in miR-302b-overexpressing cells. Nuclear factor IA (NFIA), higher levels of which were significantly related to poor survival, was identified as a direct target gene of miR-302b and was involved in miR-302b-induced glioma cell death. Higher NFIA levels were observed in GBM cell lines and human tumor sections compared with astrocytes and non-tumor tissues, respectively. NFIA knockdown significantly enhanced apoptosis. We found high levels of insulin-like growth factor-binding protein 2 (IGFBP2), another miR-302b-downregulated gene, in patients with poor survival. We verified that NFIA binds to the IGFBP2 promoter and transcriptionally enhances IGFBP2 expression levels. We identified that NFIA-mediated IGFBP2 signaling pathways are involved in miR-302b-induced glioma cell death. The identification of a regulatory loop whereby miR-302b inhibits NFIA, leading to a decrease in expression of IGFBP-2, may provide novel directions for developing therapies to target glioblastoma tumorigenesis.

MeSH terms

  • Apoptosis / genetics
  • Apoptosis / physiology
  • Astrocytes / cytology
  • Astrocytes / metabolism
  • Cell Line, Tumor
  • Cell Survival / genetics
  • Down-Regulation
  • Gene Knockdown Techniques
  • Gene Regulatory Networks
  • Glioblastoma / genetics
  • Glioblastoma / metabolism
  • Glioblastoma / pathology
  • Glioma / genetics*
  • Glioma / metabolism*
  • Glioma / pathology
  • Humans
  • Insulin-Like Growth Factor Binding Protein 2 / antagonists & inhibitors
  • Insulin-Like Growth Factor Binding Protein 2 / genetics*
  • Insulin-Like Growth Factor Binding Protein 2 / metabolism
  • MicroRNAs / genetics*
  • MicroRNAs / metabolism*
  • NFI Transcription Factors / antagonists & inhibitors*
  • NFI Transcription Factors / genetics*
  • NFI Transcription Factors / metabolism
  • Promoter Regions, Genetic
  • Signal Transduction
  • Transcriptome

Substances

  • IGFBP2 protein, human
  • Insulin-Like Growth Factor Binding Protein 2
  • MIRN302A microRNA, human
  • MicroRNAs
  • NFI Transcription Factors

Grants and funding

This work was supported by the Ministry of Science and Technology, Taiwan [MOST 104-2320-B-038-046 and MOST 105-2320-B-038-019] and Shin Kong Wu Ho-Su Memorial Hospital, Taiwan (intramural grant no. SKH-8302-105-DR-26). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.