Cyclooxygenase (COX) inhibitors induce apoptosis in non-small cell lung cancer through cyclooxygenase independent pathways.
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.
Sánchez-Alcázar
José A
JA
Division of Respiratory Medicine, Clinical Sciences Building, City Hospital, Hucknall Road, Nottingham, NG5 1PB, UK.
Bradbury
Dawn A
DA
Pang
Linhua
L
Knox
Alan J
AJ
D017209:Apoptosis / Q000187:drug effects*; D051033:Apoptosis Inducing Factor; D015153:Blotting, Western; D002289:Carcinoma, Non-Small-Cell Lung / Q000201:enzymology / Q000473:pathology*; D020169:Caspases / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology*; D003574:Cytochrome c Group / Q000378:metabolism*; D015232:Dinoprostone / Q000378:metabolism; D005420:Flavoproteins / Q000378:metabolism; D006801:Humans; D007124:Immunoenzyme Techniques; D007213:Indomethacin / Q000494:pharmacology*; D007527:Isoenzymes / Q000037:antagonists & inhibitors*; D008175:Lung Neoplasms / Q000201:enzymology / Q000473:pathology*; D008565:Membrane Proteins / Q000378:metabolism; D008856:Microscopy, Fluorescence; D009578:Nitrobenzenes / Q000494:pharmacology*; D011451:Prostaglandin-Endoperoxide Synthases; D011506:Proteins / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D015398:Signal Transduction; D013449:Sulfonamides / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
C494829:AIFM1 protein, human; D051033:Apoptosis Inducing Factor; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D003574:Cytochrome c Group; D005420:Flavoproteins; D007527:Isoenzymes; D008565:Membrane Proteins; D009578:Nitrobenzenes; D011506:Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D013449:Sulfonamides; C080955:N-(2-cyclohexyloxy-4-nitrophenyl)methanesulfonamide; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D020169:Caspases; D015232:Dinoprostone; D007213:Indomethacin