Protein nitration and nitrosylation by NO-donating aspirin in colon cancer cells: Relevance to its mechanism of action.

Abstract

Nitric oxide-donating aspirin (NO-ASA) is a promising agent for cancer prevention. Although studied extensively, its molecular targets and mechanism of action are still unclear. S-nitrosylation of signaling proteins is emerging as an important regulatory mechanism by NO. Here, we examined whether S-nitrosylation of the NF-κB, p53, and Wnt signaling proteins by NO-ASA might explain, in part, its mechanism of action in colon cancer. NO-ASA releases significant amounts of NO detected intracellularly in HCT116 and HT-29 colon cells. Using a modified biotin switch assay we demonstrated that NO-ASA S-nitrosylates the signaling proteins p53, β-catenin, and NF-κB, in colon cancer cells in a time- and concentration-dependent manner. NO-ASA suppresses NF-κB binding to its cognate DNA oligonucleotide, which occurs without changes in the nuclear levels of the NF-κB subunits p65 and p50 and is reversed by dithiothreitol that reduces -S-NO to -SH. In addition to S-nitrosylation, we documented both in vitro and in vivo widespread nitration of tyrosine residues of cellular proteins in response to NO-ASA. Our results suggest that the increased intracellular NO levels following treatment with NO-ASA modulate cell signaling by chemically modifying key protein members of signaling cascades. We speculate that S-nitrosylation and tyrosine nitration are responsible, at least in part, for the inhibitory growth effect of NO-ASA on cancer cell growth and that this may represent a general mechanism of action of NO-releasing agents.

• Authors: Jennie L Williams, Ping Ji, Nengtai Ouyang, Levy Kopelovich, Basil Rigas
• Journal: Experimental cell research (Exp Cell Res) Vol. 317 Issue 10 Pg. 1359-67 (Jun 10 2011) ISSN: 1090-2422 [Electronic] United States
• PMID: 21406194 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)
• Copyright: Copyright © 2011 Elsevier Inc. All rights reserved.

Chemical References

• NF-kappa B
• Nitric Oxide Donors
• beta Catenin
• nitroxy-butyl-acetylsalicylic acid
• Nitric Oxide
• Tyrosine
• Aspirin

Topics

• Animals
• Aspirin (analogs & derivatives, pharmacology)
• Colonic Neoplasms (drug therapy, metabolism)
• Electrophoretic Mobility Shift Assay
• Humans
• Immunoenzyme Techniques
• Male
• Mice
• Mice, Nude
• NF-kappa B (metabolism)
• Nitric Oxide (metabolism)
• Nitric Oxide Donors (pharmacology)
• Tyrosine (metabolism)
• Xenograft Model Antitumor Assays
• beta Catenin (metabolism)