The MSX1 homeobox transcription factor is a downstream target of PHOX2B and activates the Delta-Notch pathway in neuroblastoma

Exp Cell Res. 2008 Feb 15;314(4):707-19. doi: 10.1016/j.yexcr.2007.12.008. Epub 2008 Jan 16.

Abstract

Neuroblastoma is an embryonal tumour of the peripheral sympathetic nervous system (SNS). One of the master regulator genes for peripheral SNS differentiation, the homeobox transcription factor PHOX2B, is mutated in familiar and sporadic neuroblastomas. Here we report that inducible expression of PHOX2B in the neuroblastoma cell line SJNB-8 down-regulates MSX1, a homeobox gene important for embryonic neural crest development. Inducible expression of MSX1 in SJNB-8 caused inhibition of both cell proliferation and colony formation in soft agar. Affymetrix micro-array and Northern blot analysis demonstrated that MSX1 strongly up-regulated the Delta-Notch pathway genes DLK1, NOTCH3, and HEY1. In addition, the proneural gene NEUROD1 was down-regulated. Western blot analysis showed that MSX1 induction caused cleavage of the NOTCH3 protein to its activated form, further confirming activation of the Delta-Notch pathway. These experiments describe for the first time regulation of the Delta-Notch pathway by MSX1, and connect these genes to the PHOX2B oncogene, indicative of a role in neuroblastoma biology. Affymetrix micro-array analysis of a neuroblastic tumour series consisting of neuroblastomas and the more benign ganglioneuromas showed that MSX1, NOTCH3 and HEY1 are more highly expressed in ganglioneuromas. This suggests a block in differentiation of these tumours at distinct developmental stages or lineages.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Basic Helix-Loop-Helix Transcription Factors / biosynthesis
  • Basic Helix-Loop-Helix Transcription Factors / genetics
  • Basic Helix-Loop-Helix Transcription Factors / metabolism
  • Calcium-Binding Proteins
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism
  • Cell Line, Tumor
  • Cell Proliferation
  • Down-Regulation
  • Gene Expression Regulation, Neoplastic
  • Homeodomain Proteins / metabolism*
  • Humans
  • Intercellular Signaling Peptides and Proteins / genetics
  • Intercellular Signaling Peptides and Proteins / metabolism
  • Intracellular Signaling Peptides and Proteins
  • MSX1 Transcription Factor / genetics*
  • MSX1 Transcription Factor / metabolism
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Nerve Tissue Proteins / biosynthesis
  • Nerve Tissue Proteins / genetics
  • Neuroblastoma / genetics
  • Neuroblastoma / metabolism*
  • Neuroblastoma / pathology
  • Receptor, Notch3
  • Receptors, Notch / genetics
  • Receptors, Notch / metabolism*
  • Signal Transduction
  • Transcription Factors / metabolism*
  • Tumor Stem Cell Assay

Substances

  • Basic Helix-Loop-Helix Transcription Factors
  • Calcium-Binding Proteins
  • Cell Cycle Proteins
  • DLK1 protein, human
  • HEY1 protein, human
  • Homeodomain Proteins
  • Intercellular Signaling Peptides and Proteins
  • Intracellular Signaling Peptides and Proteins
  • MSX1 Transcription Factor
  • Membrane Proteins
  • NBPhox protein
  • NOTCH3 protein, human
  • Nerve Tissue Proteins
  • Receptor, Notch3
  • Receptors, Notch
  • Transcription Factors
  • delta protein
  • NeuroD protein