Positive auto-regulation of MYCN in human neuroblastoma

Yusuke Suenaga, Yoshiki Kaneko, Daisuke Matsumoto, Mohammad Shamim Hossain, Toshinori Ozaki, Akira Nakagawara

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

MYCN oncogene is one of the most important regulators affecting the prognosis of neuroblastoma and is frequently amplified in the high-risk subsets. Despite its clinical significance, it remains unclear how the MYCN expression is regulated in human neuroblastomas. Here, we found the presence of a positive auto-regulatory mechanism of MYCN. Enforced expression of MYCN induced endogenous MYCN mRNA expression in SK-N-AS neuroblastoma cells with a single copy of MYCN gene. Luciferase reporter assay revealed that MYCN protein activates its own promoter activity in a dose-dependent manner and the downstream region relative to the transcription start sites is responsible for the activation. Furthermore, ChIP analysis showed that MYCN is directly recruited onto the intron 1 region of MYCN gene which contains two putative E-box sites. Intriguingly, in response to all-trans-retinoic acid (ATRA), MYCN was down-regulated in MYCN-amplified SK-N-BE neuroblastoma cells, and the recruitment of MYCN protein onto its own intron 1 region was reduced in association with an induction of neuronal differentiation. Collectively, our present results suggest that MYCN contributes to its own expression by forming a positive auto-regulatory loop in neuroblastoma cells.

Original languageEnglish
Pages (from-to)21-26
Number of pages6
JournalBiochemical and Biophysical Research Communications
Volume390
Issue number1
DOIs
Publication statusPublished - Dec 4 2009
Externally publishedYes

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All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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