Role of N-acetyl-N-nitroso-tryptophan as nitric oxide donor in the modulation of HIF-1-dependent signaling

Biol Chem. 2010 May;391(5):533-40. doi: 10.1515/BC.2010.054.


N-Acetyl-N-nitroso-tryptophan (NANT) is well known for its capacity to generate nitric oxide (NO)-releasing compounds. It is unknown, however, whether NANT can be successfully applied as a precursor of NO in a complex biological environment such as a cell culture system. NO donors can be useful to induce the transcription factor hypoxia-inducible factor 1 (HIF-1) that coordinates the protection of cells and tissues from the lack of oxygen, termed hypoxia. HIF-1 degradation is controlled by prolyl hydroxylase 2 (PHD2) which needs to be inhibited for HIF-1 accumulation. Here, the effects of NANT in inhibiting recombinant PHD2 and up-regulating of HIF-1 and HIF-1-mediated carboanhydrase-9 (CA9) mRNA expression were compared in living cells with the NO donors N-nitrosomelatonin (NOMela) and S-nitrosoglutathione (GSNO) under normoxic and hypoxic conditions. In contrast to GSNO, NANT was similar to NOMela being highly effective in inhibiting recombinant PHD2. NANT-mediated activation of HIF-1 in oxygenated cells was comparable to hypoxic activation of HIF-1 in all cases. In contrast, under hypoxia NANT was able to boost hypoxic cellular HIF-1 levels by further reducing the activity of cellular PHD2. The strong increase of HIF-dependent CA9 mRNA expression demonstrated that NANT-induced HIF-1 was transcriptionally active. Finally, the efficacy of NANT to increase both HIF-1 and CA9 mRNA did not depend on the absolute conformation of the tryptophan moiety. In conclusion, NANT appears to be an excellent NO donor for cells in culture and l-NANT should be useful for in vivo animal studies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line, Tumor
  • Humans
  • Hypoxia-Inducible Factor 1 / physiology*
  • Nitric Oxide Donors / pharmacology*
  • Nitrosamines / pharmacology*
  • Osteosarcoma / metabolism
  • Procollagen-Proline Dioxygenase / antagonists & inhibitors
  • Signal Transduction / drug effects*
  • Tryptophan / analogs & derivatives*
  • Tryptophan / pharmacology


  • Hypoxia-Inducible Factor 1
  • N-acetyl-N-nitrosotryptophan
  • Nitric Oxide Donors
  • Nitrosamines
  • Tryptophan
  • Procollagen-Proline Dioxygenase