title: DBCCR1 mediates death in cultured bladder tumor cells.
abstract: Chromosome 9, which is often partially or fully reduced to homozygosity in bladder cancer cells, harbors several tumor suppressor loci including deleted in bladder cancer chromosome region 1 (DBCCR1) at 9q32-33. To study DBCCR1 function, stable cell lines, inducible for DBCCR1 expression by tetracycline, were made, but the DBCCR1 protein was not expressed at detectable levels. To understand the fate of DBCCR1-expressing cells, human bladder tumor cells were transiently transfected with an expression vector containing DBCCR1 fused to enhanced green fluorescent protein (EGFP). Initially, DBCCR1-EGFP-expressing cells demonstrated diffuse cytoplasmic green fluorescence with nuclear exclusion patterns. After time, the intensity level of green fluorescence increased and a granular distribution of protein became visible in the cells. At this point, cells rounded up and detached from the tissue culture dish. Cells transfected with a control vector, containing only EGFP, and partial DBCCR1-EGFP fusion constructs did not demonstrate this behavior. DBCCR1-mediated cell death in cultured tumor cells was independent of caspase-3 activation and did not result in detectable DNA strand breaks by TUNEL staining that are hallmarks of the classical apoptotic pathway.
authors.affiliation: Department of Pathology, University of Rochester, Rochester, New York, USA.
authors.forename: Kate O
authors.initials: KO
authors.lastname: Wright
authors.forename: Edward M
authors.initials: EM
authors.lastname: Messing
authors.forename: Jay E
authors.initials: JE
authors.lastname: Reeder
mesh_terms: D000818:Animals; D017209:Apoptosis; D053148:Caspase 3; D020169:Caspases / Q000502:physiology; D018797:Cell Cycle Proteins; D045744:Cell Line, Tumor; D020287:In Situ Nick-End Labeling; D051379:Mice; D041681:NIH 3T3 Cells; D009419:Nerve Tissue Proteins; D025521:Tumor Suppressor Proteins / Q000032:analysis / Q000502:physiology*; D001749:Urinary Bladder Neoplasms / Q000473:pathology*
chemical_list: C112308:BRINP1 protein, human; D018797:Cell Cycle Proteins; D009419:Nerve Tissue Proteins; D025521:Tumor Suppressor Proteins; C505407:CASP3 protein, human; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases