Salicylates inhibit NF-kappaB activation and enhance TNF-alpha-induced apoptosis in human pancreatic cancer cells

J Surg Res. 1999 May 1;83(1):56-61. doi: 10.1006/jsre.1998.5560.


Introduction: Tumor necrosis factor (TNF-alpha)-induced apoptosis is limited by its coactivation of nuclear factor kappa B (NF-kappaB)-dependent anti-apoptotic genes. Sodium salicylate (NaSal) inhibits NF-kappaB activation by limiting phosphorylation and degradation of its bound inhibitor protein, IkappaB-alpha. We examined whether NaSal enhances TNF-alpha-induced apoptosis in cultured human pancreatic cancer cell lines.

Methods: Two cultured human pancreatic cancer cell lines were studied. PANC-1 and BxPC-3 cells were serum-starved for 12 h, pretreated or not for 1 h with NaSal (5-20 mM), and then stimulated with recombinant human TNF-alpha (400 units/ml). Western blots of cytoplasmic lysates were performed to demonstrate IkappaB-alpha phosphorylation and degradation. Western blots of nuclear extracts were performed to assess nuclear translocation of NF-kappaB. In separate cultures, apoptosis was measured 4.5 h after TNF-alpha stimulation by both ELISA detection of interhistone DNA fragments and flow cytometry with propidium iodide staining.

Results: TNF-alpha induced IkappaB-alpha phosphorylation and degradation, which was inhibited by NaSal in both cell lines. TNF-alpha-induced apoptosis (DNA fragmentation) increased significantly when BxPC-3 cells were pretreated with NaSal. Flow cytometry confirmed this, demonstrating increases in apoptotic cell fractions: 8.5% (untreated), 9.3% (TNF-alpha alone), 14.9% (15 mM NaSal), and 22.9% (NaSal and TNF-alpha). In contrast, no increases in apoptosis were measured in the PANC-1 cell line among the various treatment groups.

Conclusions: NaSal enhances TNF-alpha-induced apoptosis while inhibiting IkappaB-alpha phosphorylation and degradation in BxPC-3 human pancreatic cancer cells.

MeSH terms

  • Adenocarcinoma / metabolism*
  • Adenocarcinoma / pathology
  • Apoptosis / drug effects*
  • Blotting, Western
  • Cell Nucleus / metabolism
  • DNA Fragmentation
  • DNA-Binding Proteins / metabolism
  • Enzyme-Linked Immunosorbent Assay
  • Humans
  • I-kappa B Proteins*
  • NF-KappaB Inhibitor alpha
  • NF-kappa B / antagonists & inhibitors
  • NF-kappa B / metabolism*
  • Pancreatic Neoplasms / metabolism*
  • Pancreatic Neoplasms / pathology
  • Phosphorylation
  • Sodium Salicylate / pharmacology*
  • Tumor Cells, Cultured
  • Tumor Necrosis Factor-alpha / pharmacology*


  • DNA-Binding Proteins
  • I-kappa B Proteins
  • NF-kappa B
  • NFKBIA protein, human
  • Tumor Necrosis Factor-alpha
  • NF-KappaB Inhibitor alpha
  • Sodium Salicylate