title: The p75(NTR) tumor suppressor induces cell cycle arrest facilitating caspase mediated apoptosis in prostate tumor cells.
abstract: The p75 neurotrophin receptor (p75(NTR)) is a death receptor which belongs to the tumor necrosis factor receptor super-family of membrane proteins. This study shows that p75(NTR) retarded cell cycle progression by induced accumulation of cells in G0/G1 and a reduction in the S phase of the cell cycle. The rescue of tumor cells from cell cycle progression by a death domain deleted (DeltaDD) dominant-negative antagonist of p75(NTR) showed that the death domain transduced anti-proliferative activity in a ligand-independent manner. Conversely, addition of NGF ligand rescued retardation of cell cycle progression with commensurate changes in components of the cyclin/cdk holoenzyme complex. In the absence of ligand, p75(NTR)-dependent cell cycle arrest facilitated an increase in apoptotic nuclear fragmentation of the prostate cancer cells. Apoptosis of p75(NTR) expressing cells occurred via the intrinsic mitochondrial pathway leading to a sequential caspase-9 and -7 cascade. Since the death domain deleted dominant-negative antagonist of p75(NTR) rescued intrinsic caspase associated apoptosis in PC-3 cells, this shows p75(NTR) was integral to ligand independent induction of apoptosis. Moreover, the ability of ligand to ameliorate the p75(NTR)-dependent intrinsic apoptotic cascade indicates that NGF functioned as a survival factor for p75(NTR) expressing prostate cancer cells.
authors.affiliation: Department of Biochemistry and Molecular and Cellular Biology, Georgetown University Medical Center, Washington, DC 20057-1436, USA.
authors.forename: Fatima
authors.initials: F
authors.lastname: Khwaja
authors.forename: Arshia
authors.initials: A
authors.lastname: Tabassum
authors.forename: Jeff
authors.initials: J
authors.lastname: Allen
authors.forename: Daniel
authors.initials: D
authors.lastname: Djakiew
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D020169:Caspases / Q000502:physiology*; D002453:Cell Cycle / Q000187:drug effects*; D045744:Cell Line, Tumor; D006801:Humans; D020287:In Situ Nick-End Labeling; D008297:Male; D020932:Nerve Growth Factor / Q000494:pharmacology; D009419:Nerve Tissue Proteins / Q000502:physiology*; D011471:Prostatic Neoplasms / Q000503:physiopathology*; D017475:Receptors, Nerve Growth Factor / Q000502:physiology*
chemical_list: C484065:NGFR protein, human; D009419:Nerve Tissue Proteins; D017475:Receptors, Nerve Growth Factor; D020932:Nerve Growth Factor; D020169:Caspases