A combined gene expression and functional study reveals the crosstalk between N-Myc and differentiation-inducing microRNAs in neuroblastoma cells

Oncotarget. 2016 Nov 29;7(48):79372-79387. doi: 10.18632/oncotarget.12676.

Abstract

MYCN amplification is the most common genetic alteration in neuroblastoma and plays a critical role in neuroblastoma tumorigenesis. MYCN regulates neuroblastoma cell differentiation, which is one of the mechanisms underlying its oncogenic function. We recently identified a group of differentiation-inducing microRNAs. Given the demonstrated inter-regulation between MYCN and microRNAs, we speculated that MYCN and the differentiation-inducing microRNAs might form an interaction network to control the differentiation of neuroblastoma cells. In this study, we found that eight of the thirteen differentiation-inducing microRNAs, miR-506-3p, miR-124-3p, miR-449a, miR-34a-5p, miR-449b-5p, miR-103a-3p, miR-2110 and miR-34b-5p, inhibit N-Myc expression by either directly targeting the MYCN 3'UTR or through indirect regulations. Further investigation showed that both MYCN-dependent and MYCN-independent pathways play roles in mediating the differentiation-inducing function of miR-506-3p and miR-449a, two microRNAs that dramatically down-regulate MYCN expression. On the other hand, we found that N-Myc inhibits the expression of multiple differentiation-inducing microRNAs, suggesting that these miRNAs play a role in mediating the function of MYCN. In examining the published dataset collected from clinical neuroblastoma specimens, we found that expressions of two miRNAs, miR-137 and miR-2110, were significantly anti-correlated with MYCN mRNA levels, suggesting their interactions with MYCN play a clinically-relevant role in maintaining the MYCN and miRNA expression levels in neuroblastoma. Our findings altogether suggest that MYCN and differentiation-inducing miRNAs form an interaction network that play an important role in neuroblastoma tumorigenesis through regulating cell differentiation.

Keywords: MYCN; differentiation; microRNA; neuroblastoma.

MeSH terms

  • 3' Untranslated Regions
  • Cell Differentiation
  • Cell Line, Tumor
  • Down-Regulation
  • Gene Expression Profiling / methods*
  • Gene Expression Regulation, Neoplastic
  • Gene Regulatory Networks
  • Humans
  • MicroRNAs / genetics*
  • N-Myc Proto-Oncogene Protein / genetics*
  • Neuroblastoma / genetics*

Substances

  • 3' Untranslated Regions
  • MYCN protein, human
  • MicroRNAs
  • N-Myc Proto-Oncogene Protein