Inhibition of NF-kappa B with proteasome inhibitors enhances apoptosis in human lung adenocarcinoma cells in vitro.
BACKGROUND
Nuclear factor-kappa B (NF-kappa B) nuclear translocation has an important role in preventing apoptotic cell death in some cancers. However, little is known about the role of NF-kB in non-small cell carcinoma.


METHODS
Human lung adenocarcinoma cells were stimulated with tumor necrosis factor (TNF) alone or TNF with proteasome inhibitors to block NF-kappa B translocation. Cytotoxicity assays, histone-associated DNA-fragmentation ELISA, immunoblots of poly-(ADP ribose)-polymerase (PARP) and electron microscopy were used to evaluate apoptosis.


RESULTS
TNF induced I kappa B proteolysis and NF-kappa B nuclear translocation; however, this was blocked by pretreatment with proteasome inhibitors. TNF alone was not cytotoxic, but when NF-kappa B was blocked TNF induced cell death. Specifically, the cytotoxicity was due to apoptosis as noted by increased DNA-fragmentation, degradation of PARP and characteristic morphology.


CONCLUSIONS
Proteasome inhibition was an effective method to inhibit NF-kappa B activation in lung adenocarcinoma cells. TNF in conjunction with. NF-kappa B inhibition was a potent stimulus for apoptosis.
Milligan
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Section of Pulmonary Medicine, Medical Service (111P), VA Medical Center, 510 East Stoner Avenue, Shreveport, LA 71101, USA. shawn.milligan@med.va.gov
Nopajaroonsri
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C
D000111:Acetylcysteine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000230:Adenocarcinoma / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D003546:Cysteine Endopeptidases; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology*; D053938:DNA Fragmentation / Q000187:drug effects; D004268:DNA-Binding Proteins / Q000378:metabolism; D006801:Humans; D020672:I-kappa B Proteins; D007976:Leupeptins / Q000494:pharmacology; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D009097:Multienzyme Complexes / Q000037:antagonists & inhibitors; D016328:NF-kappa B / Q000378:metabolism*; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; D046988:Proteasome Endopeptidase Complex; D011506:Proteins / Q000378:metabolism; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D000970:Antineoplastic Agents; D015853:Cysteine Proteinase Inhibitors; D004268:DNA-Binding Proteins; C083487:I kappa B beta protein; D020672:I-kappa B Proteins; D007976:Leupeptins; D009097:Multienzyme Complexes; D016328:NF-kappa B; D011506:Proteins; D014409:Tumor Necrosis Factor-alpha; C067713:lactacystin; C499320:PARP1 protein, human; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde; D000111:Acetylcysteine