Cyclooxygenase (COX) inhibitors induce apoptosis in non-small cell lung cancer through cyclooxygenase independent pathways

• Published in: Lung cancer (Amsterdam, Netherlands) Netherlands), 2003-04, Vol.40 (1), p.33-44
• Main Authors: Sánchez-Alcázar, José A, Bradbury, Dawn A, Pang, Linhua, Knox, Alan J
• Format: Article
• Language: English
• Subjects: Apoptosis; Apoptosis - drug effects; Apoptosis Inducing Factor; Biological and medical sciences; Blotting, Western; Carcinoma, Non-Small-Cell Lung - enzymology; Carcinoma, Non-Small-Cell Lung - pathology; Caspases - metabolism; Cell Survival - drug effects; Cyclooxygenase; Cyclooxygenase 2; Cyclooxygenase 2 Inhibitors; Cyclooxygenase Inhibitors - pharmacology; Cytochrome c Group - metabolism; Dinoprostone - metabolism; Flavoproteins - metabolism; Humans; Immunoenzyme Techniques; Indomethacin; Indomethacin - pharmacology; Isoenzymes - antagonists & inhibitors; Lung cancer; Lung Neoplasms - enzymology; Lung Neoplasms - pathology; Medical sciences; Membrane Proteins - metabolism; Microscopy, Fluorescence; Nitrobenzenes - pharmacology; Pneumology; Prostaglandin-Endoperoxide Synthases; Proteins - metabolism; Proto-Oncogene Proteins c-bcl-2 - metabolism; Signal Transduction; Sulfonamides - pharmacology; Tumor Cells, Cultured; Tumors of the respiratory system and mediastinum
• ISSN: 0169-5002; 1872-8332
• DOI: 10.1016/S0169-5002(02)00530-5

Cyclooxygenase (COX) inhibitors are chemopreventive in many tumours but the role of COX inhibition in their effects is contentious. Here we determined if COX inhibitors influenced apoptosis in two non-small cell lung cancer cells one which over expresses COX-2 (MOR-P) and one which expresses neither isoform (H-460). NS398, a selective COX inhibitor, and indomethacin, a non-selective COX inhibitor, were cytotoxic in both cell lines, independently of their COX-2 expression. Furthermore, the cytotoxic concentrations were far greater than the concentrations required to inhibit COX. As indomethacin was more effective we used it in mechanistic studies. Indomethacin induced apoptotic cell death assessed as cytochrome c and apoptotic inducing factor (AIF) release, caspase activation, PARP, lamin B and gelsolin cleavage, chromatin condensation and nuclear fragmentation. The pan-caspase inhibitor, z-VAD, attenuated cell death, and blocked caspase activation, PARP cleavage and nuclear fragmentation without preventing cytochrome c release, suggesting that cytochrome c release is upstream of caspase activation. These observations suggest that COX inhibitors induce apoptosis in non-small lung cancer cells through cytochrome c and AIF release, and subsequent caspase activation, independently of COX-2 expression and prostaglandin production.