6-(7-Nitro-2,1,3-benzoxadiazol-4-ylthio)hexanol, a specific glutathione S-transferase inhibitor, overcomes the multidrug resistance (MDR)-associated protein 1-mediated MDR in small cell lung cancer.

Abstract

In the present work, we have investigated the antitumor activity of 6-(7-nitro-2,1,3-benzoxadiazol-4-ylthio)hexanol (NBDHEX) on aggressive small cell lung cancer. NBDHEX not only is cytotoxic toward the parental small cell lung cancer H69 cell line (LC(50) of 2.3 +/- 0.6 micromol/L) but also overcomes the multidrug resistance of its variant, H69AR, which overexpresses the ATP-binding cassette transporter multidrug resistance-associated protein 1 (MRP1; LC(50) of 4.5 +/- 0.9 micromol/L). Drug efflux experiments, done in the presence of a specific inhibitor of MRP1, confirmed that NBDHEX is not a substrate for this export pump. Interestingly, NBDHEX triggers two different types of cell death: a caspase-dependent apoptosis in the H69AR cells and a necrotic phenotype in the parental H69 cells. The apoptotic pathway triggered by NBDHEX in H69AR cells is associated with c-Jun NH(2)-terminal kinase and c-Jun activation, whereas glutathione oxidation and activation of p38(MAPK) is observed in the NBDHEX-treated H69 cells. In contrast to the parental cells, the higher propensity to die through apoptosis of the H69AR cell line may be related to the lower expression of the antiapoptotic protein Bcl-2. Therefore, down-regulation of a factor crucial for cell survival makes H69AR cells more sensitive to the cytotoxic action of NBDHEX, which is not a MRP1 substrate. We have previously shown that NBDHEX is cytotoxic toward P-glycoprotein-overexpressing tumor cell lines. Therefore, NBDHEX seems a very promising compound in the search for new molecules able to overcome the ATP-binding cassette family of proteins, one of the major mechanisms of multidrug resistance in cancer cells.

• Authors: Giuseppe Filomeni, Paola Turella, Maria Luisa Dupuis, Olindo Forini, Maria Rosa Ciriolo, Maurizio Cianfriglia, Silvia Pezzola, Giorgio Federici, Anna Maria Caccuri
• Journal: Molecular cancer therapeutics (Mol Cancer Ther) Vol. 7 Issue 2 Pg. 371-9 (Feb 2008) ISSN: 1535-7163 [Print] United States
• PMID: 18281520 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• 6-(7-nitro-2,1,3-benzoxadiazol-4-ylthio)hexanol
• ATP Binding Cassette Transporter, Subfamily B, Member 1
• Antineoplastic Agents
• Hexanols
• Oxadiazoles
• Proto-Oncogene Proteins c-jun
• Glutathione Transferase
• JNK Mitogen-Activated Protein Kinases
• p38 Mitogen-Activated Protein Kinases
• Glutathione

Topics

• ATP Binding Cassette Transporter, Subfamily B, Member 1 (genetics, metabolism, physiology)
• Antineoplastic Agents (pharmacology)
• Apoptosis (drug effects)
• Carcinoma, Small Cell (enzymology, pathology)
• Cell Line, Tumor
• Dose-Response Relationship, Drug
• Drug Evaluation, Preclinical
• Drug Resistance, Multiple (drug effects, genetics)
• Drug Resistance, Neoplasm (drug effects, genetics)
• Enzyme Activation (drug effects)
• Glutathione (metabolism)
• Glutathione Transferase (antagonists & inhibitors)
• Hexanols (pharmacology)
• Humans
• JNK Mitogen-Activated Protein Kinases (metabolism)
• Lung Neoplasms (enzymology, pathology)
• Necrosis (chemically induced)
• Oxadiazoles (pharmacology)
• Oxidation-Reduction (drug effects)
• Proto-Oncogene Proteins c-jun (metabolism)
• Substrate Specificity
• p38 Mitogen-Activated Protein Kinases (metabolism)