title: Expression of NF-κB-related proteins and their modulation during TNF-α-provoked apoptosis in prostate cancer cells.
abstract: BACKGROUND
  The involvement of TNF-α in cancer development is controversial, since this cytokine was reported to act either as tumor promoter or suppressor. TNF-α may activate signaling pathways critical for life/death decisions, such as mitogen-activated protein kinases (MAPKs) and the anti-apoptotic NF-κB pathway. In this work, we investigate the activation status of NF-κB-related proteins in human prostate cancerous versus normal epithelium, and the alterations in the NF-κB pathway in relation to cell death in TNF-α-treated LNCaP (androgen-independent cells) and PC3 (androgen-independent) prostate cancer cell lines.
  
  
  METHODS
  The expression of phospho-p38-MAPK, phospho-IKK-α/β and phospho-IκB-α, total IκB-α, and p65- and p50-NF-κB, were analyzed by immunohistochemistry in cancerous and normal prostate samples. The toxicity of TNF-α in LNCaP and PC3 cells, with or without kinase and NF-κB inhibitors, was assessed by changes on viability (MTT assay) and apoptosis (loss of DNA, annexin-V binding, and caspase cleavage/activation). Expression of NF-κB-related proteins in these cell lines was measured by Western blot.
  
  
  RESULTS
  Phospho-IκB-α, phospho-IKK-α/β and phospho-p38 levels, cytoplasmic p50 to IκB-α ratio, and nuclear p50 and p65, levels, were increased in cancerous epithelium, suggesting activation of the NF-κB pathway in prostatic malignance. TNF-α caused apoptosis with higher efficacy in LNCaP cells, and this response was potentiated by p38-MAPK inhibitor (LNCaP cells) and IKK-β inhibitor (both cell lines). However, the protective action of IKK-β was mediated by NF-κB only in LNCaP cells.
  
  
  CONCLUSIONS
  IKK-β mediates both NF-κB-dependent and -independent anti-apoptotic functions in prostate cancerous epithelium. IKK-β and p38-MAPK may represent useful therapeutic targets against prostate cancer.
authors.affiliation: Departamento de Biología Celular y Genética, Universidad de Alcalá, Madrid, Spain. gonzalo.rodriguezb@uah.es
authors.forename: Gonzalo
authors.initials: G
authors.lastname: Rodríguez-Berriguete
authors.forename: Benito
authors.initials: B
authors.lastname: Fraile
authors.forename: Ricardo
authors.initials: R
authors.lastname: Paniagua
authors.forename: Patricio
authors.initials: P
authors.lastname: Aller
authors.forename: Mar
authors.initials: M
authors.lastname: Royuela
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism*; D000368:Aged; D017209:Apoptosis / Q000187:drug effects*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D051550:I-kappa B Kinase / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects / Q000502:physiology; D011471:Prostatic Neoplasms / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism / Q000494:pharmacology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D016328:NF-kappa B; D014409:Tumor Necrosis Factor-alpha; D051550:I-kappa B Kinase; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases