Compound C stimulates heme oxygenase-1 gene expression via the Nrf2-ARE pathway to preserve human endothelial cell survival

Biochem Pharmacol. 2011 Aug 15;82(4):371-9. doi: 10.1016/j.bcp.2011.05.016. Epub 2011 May 24.


We recently identified adenosine monophosphate-activated protein kinase (AMPK) as a novel inducer of heme oxygenase-1 (HO-1) and surprisingly found that compound C (6-[4-(2-piperidin-1-yl-ethoxy)-phenyl]-3-pyridin-4-yl-pyrazolo[1,5-a] pyrimidine), a cell-permeable inhibitor of AMPK, could also elevate HO-1 suggesting other AMPK-independent actions for this agent. In this study, we investigated the biochemical mechanism by which compound C stimulates HO-1 expression in human endothelial cells (ECs) and determined the biological significance of the induction of HO-1 by compound C in these cells. Compound C stimulated a concentration- and time-dependent increase in HO-1 expression and an increase in HO-1 promoter activity that was abrogated by mutating the antioxidant responsive elements (AREs) in the HO-1 promoter or by overexpressing a dominant negative mutant of NF-E2-related factor 2 (Nrf2). Compound C also stimulated Nrf2 expression this was associated with an increase in the production of reactive oxygen species and with a decline in intracellular glutathione levels. Interestingly, the glutathione donor N-acetyl-l-cysteine or the NADPH oxidase inhibitor apocynin blocked the induction of HO-1 by compound C. Finally, compound C stimulated EC death and this was potentiated by silencing HO-1 expression and reversed by the administration of CO, biliverdin, or bilirubin. In conclusion, this study demonstrates that compound C stimulates HO-1 gene expression in human vascular endothelium via the activation of the Nrf2/ARE signaling pathway to counteract compound C-mediated cell death. The ability of compound C to induce HO-1 expression may contribute to the pleiotropic actions of this agent and suggest caution when using compound C to probe for AMPK functions.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • AMP-Activated Protein Kinases / antagonists & inhibitors
  • AMP-Activated Protein Kinases / metabolism
  • Antioxidants / metabolism
  • Cell Survival / drug effects
  • Cell Survival / physiology
  • Cells, Cultured
  • Endothelium, Vascular / cytology*
  • Endothelium, Vascular / drug effects
  • Endothelium, Vascular / enzymology*
  • Gene Expression Regulation, Enzymologic*
  • Heme Oxygenase-1 / biosynthesis*
  • Humans
  • NF-E2-Related Factor 2 / biosynthesis*
  • Pyrazoles / pharmacology*
  • Pyrimidines / pharmacology*
  • Response Elements / drug effects
  • Response Elements / physiology*
  • Signal Transduction / drug effects
  • Signal Transduction / physiology


  • Antioxidants
  • NF-E2-Related Factor 2
  • Pyrazoles
  • Pyrimidines
  • dorsomorphin
  • Heme Oxygenase-1
  • AMP-Activated Protein Kinases