N-myc is a novel regulator of PI3K-mediated VEGF expression in neuroblastoma

J. Kang, P. G. Rychahou, T. A. Ishola, J. M. Mourot, B. M. Evers, D. H. Chung

Research output: Contribution to journalArticlepeer-review

85 Scopus citations


Angiogenesis in neuroblastoma (NB) correlates with increased expression of vascular endothelial growth factor (VEGF) and a worse clinical outcome. Other cellular markers, such as Akt activation and MYCN amplification, are also associated with poor prognosis in NB; therefore, we sought to determine the role of N-myc in the regulation of the phosphatidylinositol 3-kinase (PI3K)/Akt/VEGF pathway. PI3K inhibition, using small-molecule inhibitors or phosphatase and tensin homolog adenovirus, led to decreased levels of VEGF mRNA and/or protein by reducing phosphorylation of Akt and mammalian target of rapamycin (mTOR), and attenuating hypoxia-inducible factor 1α expression. Moreover, PI3K inhibition decreased levels of N-myc expression in MYCN-amplified cells. To further clarify the importance of N-myc as a target of PI3K in VEGF regulation, we inhibited N-myc expression by siRNA transfection. MYCN siRNA significantly blocked VEGF secretion, irrespective of serum conditions, in MYCN-amplified NB cells; this effect was enhanced when combined with rapamycin, an mTOR inhibitor. Interestingly, in cells with low-N-myc expression, MYCN siRNA reduction of VEGF secretion was only effective with MYCN overexpression or insulin-like growth factor-1 stimulation. Our results show that N-myc plays an important role in the PI3K-mediated VEGF regulation in NB cells. Targeting MYCN, as a novel effector of PI3K-mediated angiogenesis, has significant potential for the treatment of highly vascularized, malignant NB.

Original languageEnglish
Pages (from-to)3999-4007
Number of pages9
Issue number28
StatePublished - Jun 26 2008

Bibliographical note

Funding Information:
We thank Dr Mark R Hellmich for helpful advice on PECAM-1 experiments, Karen K Martin for manuscript preparation and Tatsuo Uchida for statistical analysis. This work was supported by grants RO1 DK61470, RO1 DK48498, RO1 CA104748 and PO1 DK35608 from the National Institutes of Health.


  • Angiogenesis
  • MYCN
  • Neuroblastoma
  • PI3K/Akt
  • VEGF

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Cancer Research


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