title: Overexpression of BAD potentiates sensitivity to tumor necrosis factor-related apoptosis-inducing ligand treatment in the prostatic carcinoma cell line LNCaP.
abstract: Here we show that LNCaP, which is resistant to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis, becomes sensitive to TRAIL after overexpression of full-length, wild-type BAD (BAD WT). TRAIL induces caspase-dependent cleavage of BAD WT that results in generation of a M(r) 15,000 protein. LNCaP stably expressing truncated BAD (tBAD) and cells expressing mutated BAD at the caspase cleavage site were less sensitive to TRAIL treatment when compared to LNCaP expressing BAD WT. Cytochrome c and Smac/DIABLO release from mitochondria into cytosol was found after TRAIL treatment only in cells overexpressing BAD WT. Furthermore, differences in phosphorylation of serine residues for BAD WT and tBAD were identified. BAD WT was phosphorylated at positions S136 and S155, whereas tBAD was phosphorylated at positions S112, S136, and S155. LNCaP stably expressing BAD mutated at serine 112 to alanine was less sensitive to TRAIL treatment when compared to LNCaP expressing BAD WT. Lastly, recombinant BAD cleaved by caspase-3 is a more potent inducer of cytochrome c and Smac/DIABLO release than BAD WT. In summary, BAD-mediated sensitivity of LNCaP to TRAIL depends on the phosphorylation status of BAD WT and tBAD.
authors.affiliation: Department of Pathology, The University of Iowa, 200 Hawkins Drive, Iowa City, IA 52242-1087, USA.
authors.forename: Agshin F
authors.initials: AF
authors.lastname: Taghiyev
authors.forename: Natalya V
authors.initials: NV
authors.lastname: Guseva
authors.forename: Hisashi
authors.initials: H
authors.lastname: Harada
authors.forename: C Michael
authors.initials: CM
authors.lastname: Knudson
authors.forename: Oskar W
authors.initials: OW
authors.lastname: Rokhlin
authors.forename: Michael B
authors.initials: MB
authors.lastname: Cohen
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins; D002352:Carrier Proteins / Q000235:genetics*; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002470:Cell Survival; D003600:Cytosol / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000494:pharmacology*; D051379:Mice; D008928:Mitochondria / Q000378:metabolism; D010766:Phosphorylation; D011471:Prostatic Neoplasms / Q000473:pathology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics; D053221:TNF-Related Apoptosis-Inducing Ligand; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D051025:bcl-Associated Death Protein
chemical_list: D051017:Apoptosis Regulatory Proteins; C494819:BAD protein, human; C494820:Bad protein, mouse; D002352:Carrier Proteins; D008562:Membrane Glycoproteins; D019253:Proto-Oncogene Proteins c-bcl-2; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; C505654:Tnfsf10 protein, mouse; D014409:Tumor Necrosis Factor-alpha; D051025:bcl-Associated Death Protein; C505407:CASP3 protein, human; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases