Increased NF-kappaB DNA binding but not transcriptional activity during apoptosis induced by the COX-2-selective inhibitor NS-398 in colorectal carcinoma cells.
Nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit colorectal neoplasia, an effect that is associated with their ability to induce apoptosis. Although NSAIDs have been reported to inhibit NF-kappaB, more recent studies show activation of NF-kappaB by NSAIDs. NF-kappaB commonly shows antiapoptotic activity and is implicated in the therapeutic resistance of cancer cells. The effects of highly COX-2-selective NSAIDs such as NS-398 on NF-kappaB in colorectal tumour cells have not been reported. Therefore, we addressed whether NF-kappaB has a role in NS-398-induced apoptosis of colorectal cancer cells. Treatment of HT-29 colorectal carcinoma cells with doses of NS-398 (50-75 microM) known to induce apoptosis had no effect on NF-kappaB for up to 48 h. However after 72 and 96 h NF-kappaB DNA-binding activity was increased by NS-398, in parallel with apoptosis induction. NS-398-treated HT-29 cells showed increased p50 homodimer binding and an induction of p50/p65 heterodimers, as demonstrated by supershift assay. However, although NS-398 increased NF-kappaB DNA binding it did not increase NF-kappaB-dependent reporter activity and inhibition of NF-kappaB DNA binding did not enhance NS-398-induced apoptosis. This indicates that NF-kappaB activated by NS-398 is transcriptionally inactive and is an encouraging result for the use of COX-2-selective NSAIDs not only in chemoprevention but also as novel therapies for colon cancer.
Smartt
H J M
HJ
Cancer Research UK Colorectal Tumour Biology Research Group, Department of Pathology and Microbiology, School of Medical Sciences, University of Bristol, University Walk, Bristol BS8 1TD, UK.
Elder
D J E
DJ
Hicks
D J
DJ
Williams
N A
NA
Paraskeva
C
C
D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D015179:Colorectal Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology*; D004273:DNA, Neoplasm / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D019073:HT29 Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007527:Isoenzymes / Q000037:antagonists & inhibitors*; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D009578:Nitrobenzenes / Q000494:pharmacology*; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D011451:Prostaglandin-Endoperoxide Synthases; D011485:Protein Binding; D013449:Sulfonamides / Q000494:pharmacology*; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014162:Transfection
D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D004273:DNA, Neoplasm; D007527:Isoenzymes; D008565:Membrane Proteins; D016328:NF-kappa B; D009578:Nitrobenzenes; D013449:Sulfonamides; C080955:N-(2-cyclohexyloxy-4-nitrophenyl)methanesulfonamide; D008156:Luciferases; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D011065:Poly(ADP-ribose) Polymerases