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Combined IFN-gamma and retinoic acid treatment targets the N-Myc/Max/Mad1 network resulting in repression of N-Myc target genes in MYCN-amplified neuroblastoma cells

Author:
  • Cihan Cetinkaya
  • Anne Hultquist
  • Yingtao Su
  • Siqin Wu
  • Fuad Bahram
  • Sven Påhlman
  • Irina Guzhova
  • Lars-Gunnar Larsson
Publishing year: 2007
Language: English
Pages: 2634-2641
Publication/Series: Molecular Cancer Therapeutics
Volume: 6
Issue: 10
Document type: Journal article
Publisher: American Association for Cancer Research

Abstract english

The MYCN protooncogene is involved in the control of cell proliferation, differentiation, and survival of neuroblasts. Deregulation of MYCN by gene amplification contributes to neuroblastoma development and is strongly correlated to advanced disease and poor outcome, emphasizing the urge for new therapeutic strategies targeting MYCN function. The transcription factor N-Myc, encoded by MYCN, regulates numerous genes together with its partner Max, which also functions as a cofactor for the Mad/Mnt family of Myc antagonists/transcriptional repressors. We and others have previously reported that IFN-gamma synergistically potentiates retinoic acid (RA)induced sympathetic differentiation and growth inhibition in neuroblastoma cells. This study shows that combined treatment of MYCN-amplified neuroblastorna cells with RA+IFN-gamma down-regulates N-Myc protein expression through increased protein turnover, up-regulates Mad1 mRNA and protein, and reduces N-Myc/Max heteroclimerization. This results in a shift of occupancy at the ornithine decarboxylase N-Myc/Mad1 target promoter in vivo from N-Myc/Max to Madl/Max predominance, correlating with histone H4 deacetylation, indicative of a chromatin structure typical of a transcriptionally repressed state. This is further supported by data showing that RA + IFN-gamma treatment strongly represses expression of N-Myc/Mad1 target genes ornithine decarboxylase and hTERT. Our results suggest that combined IFN-gamma and RA signaling can form a basis for new therapeutic strategies targeting N-Myc function for patients with high-risk, MYCN-amplified neuroblastoma.

Keywords

  • Cancer and Oncology

Other

Published
  • ISSN: 1538-8514
Sven Påhlman
E-mail: sven.pahlman [at] med.lu.se

Professor

Division of Translational Cancer Research

+46 46 222 64 21

MV406 312K1

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