5-Aza-2'-deoxycytidine stimulates inducible nitric oxide synthase induction in C6 astrocytoma cells

Brain Res. 2004 Feb 13;998(1):83-90. doi: 10.1016/j.brainres.2003.11.014.

Abstract

The influence of a nucleoside analog 5-aza-2'-deoxycytidine (5-AzadC) on inducible nitric oxide synthase (iNOS)-dependent nitric oxide (NO) production in various rat cell types was investigated. In C6 astrocytoma cell line and primary astrocytes, 5-AzadC enhanced proinflammatory cytokine (IFN-gamma, TNF-alpha, IL-1)-triggered NO synthesis in a time- and dose-dependent manner. In contrast, 5-AzadC did not potentiate NO production in IFN-gamma-stimulated macrophages, fibroblasts, or endothelial cells. Blockade of transcription or translation in C6 cells abolished the observed effect, suggesting the iNOS gene expression, rather than its catalytic activity, as a target for the drug action. Accordingly, 5-AzadC upregulated IFN-gamma-induced expression of iNOS mRNA in C6 astrocytes. The effect of 5-AzadC on astrocyte NO release was blocked by the inhibitor of p44/42 mitogen activated protein kinase-dependent signaling. Finally, the observed stimulatory effect of 5-AzadC on iNOS expression was apparently independent of DNA demethylation, as DNA digestion with methylation-sensitive restriction enzyme HpaII showed that 5-AzadC failed to demethylate cellular DNA in conditions used for iNOS induction.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Newborn
  • Antimetabolites, Antineoplastic / pharmacology*
  • Astrocytes / drug effects*
  • Astrocytoma / pathology
  • Azacitidine / analogs & derivatives*
  • Azacitidine / pharmacology*
  • Blotting, Northern
  • Cells, Cultured
  • DNA Methylation / drug effects
  • DNA Modification Methylases / antagonists & inhibitors*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Decitabine
  • Dose-Response Relationship, Drug
  • Drug Interactions
  • Enzyme Induction / drug effects
  • Gene Expression / drug effects
  • Interferon Regulatory Factor-1
  • Interferons / pharmacology
  • Interleukin-1 / pharmacology
  • Mitogen-Activated Protein Kinase 1 / metabolism
  • Mitogen-Activated Protein Kinase 3
  • Mitogen-Activated Protein Kinases / metabolism
  • Nitric Oxide Synthase / biosynthesis*
  • Phosphoproteins / genetics
  • Phosphoproteins / metabolism
  • RNA, Messenger / biosynthesis
  • Rats
  • Reverse Transcriptase Polymerase Chain Reaction / methods
  • Time Factors
  • Tumor Necrosis Factor-alpha / pharmacology

Substances

  • Antimetabolites, Antineoplastic
  • DNA-Binding Proteins
  • Interferon Regulatory Factor-1
  • Interleukin-1
  • Irf1 protein, rat
  • Phosphoproteins
  • RNA, Messenger
  • Tumor Necrosis Factor-alpha
  • Decitabine
  • Interferons
  • Nitric Oxide Synthase
  • DNA Modification Methylases
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase 3
  • Mitogen-Activated Protein Kinases
  • Azacitidine