Tumor cell responses to a novel glutathione S-transferase-activated nitric oxide-releasing prodrug.

Abstract

We have used structure-based design techniques to introduce the drug O(2)-[2,4-dinitro-5-(N-methyl-N-4-carboxyphenylamino) phenyl] 1-N,N-dimethylamino)diazen-1-ium-1,2-diolate (PABA/NO), which is efficiently metabolized to potentially cytolytic nitric oxide by the pi isoform of glutathione S-transferase, an enzyme expressed at high levels in many tumors. We have used mouse embryo fibroblasts (MEFs) null for GSTpi (GSTpi(-/-)) to show that the absence of GSTpi results in a decreased sensitivity to PABA/NO. Cytotoxicity of PABA/NO was also examined in a mouse skin fibroblast (NIH3T3) cell line that was stably transfected with GSTpi and/or various combinations of gamma-glutamyl cysteine synthetase and the ATP-binding cassette transporter MRP1. Overexpression of MRP1 conferred the most significant degree of resistance, and in vitro transport studies confirmed that a GSTpi-activated metabolite of PABA/NO was effluxed by MRP1 in a GSH-dependent manner. Additional studies showed that in the absence of MRP1, PABA/NO activated the extracellular-regulated and stress-activated protein kinases ERK, c-Jun NH(2)-terminal kinase (JNK), and p38. Selective inhibition studies showed that the activation of JNK and p38 were critical to the cytotoxic effects of PABA/NO. Finally, PABA/NO produced antitumor effects in a human ovarian cancer model grown in SCID mice.

• Authors: Victoria J Findlay, Danyelle M Townsend, Joseph E Saavedra, Gregory S Buzard, Michael L Citro, Larry K Keefer, Xinhua Ji, Kenneth D Tew
• Journal: Molecular pharmacology (Mol Pharmacol) Vol. 65 Issue 5 Pg. 1070-9 (May 2004) ISSN: 0026-895X [Print] United States
• PMID: 15102935 (Publication Type: Journal Article, Research Support, U.S. Gov't, P.H.S.)

Chemical References

• Azo Compounds
• Isoenzymes
• Multidrug Resistance-Associated Proteins
• Nitric Oxide Donors
• O(2)-(2,4-dinitro-5-(N-methyl-N-4-carboxyphenylamino)phenyl 1-N,N-dimethylamino)diazen-1-ium-1,2-diolate
• O(2)-(2,4-dinitrophenyl) 1-((4-ethoxycarbonyl)piperazin-1-yl)diazen-1-ium-1,2-diolate
• Piperazines
• Prodrugs
• para-Aminobenzoates
• Leukotriene C4
• Nitric Oxide
• Glutathione S-Transferase pi
• Glutathione Transferase
• Gstp1 protein, mouse
• JNK Mitogen-Activated Protein Kinases
• Mitogen-Activated Protein Kinases
• p38 Mitogen-Activated Protein Kinases
• 4-Aminobenzoic Acid

Topics

• 3T3 Cells
• 4-Aminobenzoic Acid (chemical synthesis, chemistry, pharmacology)
• Animals
• Azo Compounds (chemical synthesis, chemistry, pharmacology)
• Cell Division (drug effects)
• Enzyme Activation (drug effects)
• Glutathione S-Transferase pi
• Glutathione Transferase (metabolism)
• Isoenzymes (metabolism)
• JNK Mitogen-Activated Protein Kinases
• Leukotriene C4 (metabolism)
• Mice
• Mice, SCID
• Mitogen-Activated Protein Kinases (metabolism)
• Multidrug Resistance-Associated Proteins (metabolism)
• Nitric Oxide (metabolism)
• Nitric Oxide Donors (pharmacology)
• Piperazines (pharmacology)
• Prodrugs (pharmacology)
• Tumor Cells, Cultured
• p38 Mitogen-Activated Protein Kinases
• para-Aminobenzoates