title: p53 is involved in tumor necrosis factor-alpha-induced apoptosis in the human prostatic carcinoma cell line LNCaP.
abstract: The human prostatic carcinoma cell line LNCaP is sensitive to TNF-alpha treatment and expresses wild-type p53. To analyse the possible role of p53 in TNF-alpha-mediated apoptosis, we generated a derivative of LNCaP, LN-56, expressing a dominant-negative element of p53, GSE56. P53 inactivation in LN-56 was associated with an increased resistance to apoptosis induced by TNF-alpha. Surface expression of TNF-alpha receptors was unchanged in LN-56 compared to LNCaP. TNF-alpha treatment resulted in accumulation of p53 in LNCaP and upregulation of p21/WAF1. Activation of caspase-7 and PARP proteolysis were delayed in LN-56 under TNF-alpha treatment. TNF-alpha-induced apoptosis in LNCaP cells was accompanied by caspase-dependent proteolysis of p21/WAF1 and Rb, which was significantly attenuated in LN-56. Cytochrome c release was induced by TNF-alpha treatment in both cell lines, but caspase-9 was not activated. LNCaP and LN-56 were injected s.c. in nude mice and tumors were identified in all LN-56, but not LNCaP, bearing mice indicating that p53 plays an important role in growth control of prostatic neoplasms. Interestingly, accumulation of p53 in TNF-alpha-treated LNCaP cells was decreased in the presence of the caspase inhibitor Z-VAD-FMK, suggesting a new role of activated caspases in acceleration of p53 response. In summary, these results indicate that p53 is involved in TNF-alpha-mediated apoptosis in LNCaP.
authors.affiliation: Department of Pathology, The University of Iowa, Iowa City, Iowa, IA 52242, USA.
authors.forename: O W
authors.initials: OW
authors.lastname: Rokhlin
authors.forename: A V
authors.initials: AV
authors.lastname: Gudkov
authors.forename: S
authors.initials: S
authors.lastname: Kwek
authors.forename: R A
authors.initials: RA
authors.lastname: Glover
authors.forename: A S
authors.initials: AS
authors.lastname: Gewies
authors.forename: M B
authors.initials: MB
authors.lastname: Cohen
mesh_terms: D000818:Animals; D017209:Apoptosis; D020169:Caspases / Q000378:metabolism; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000378:metabolism; D003574:Cytochrome c Group / Q000378:metabolism; D006801:Humans; D008297:Male; D051379:Mice; D008819:Mice, Nude; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; D011471:Prostatic Neoplasms / Q000378:metabolism / Q000473:pathology*; D011506:Proteins / Q000378:metabolism; D016160:Retinoblastoma Protein / Q000378:metabolism; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D016159:Tumor Suppressor Protein p53 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: C493956:CDKN1A protein, human; C493957:Cdkn1a protein, mouse; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D003574:Cytochrome c Group; D011506:Proteins; D016160:Retinoblastoma Protein; D014409:Tumor Necrosis Factor-alpha; D016159:Tumor Suppressor Protein p53; C499321:Parp1 protein, mouse; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; D020169:Caspases