title: Modulation of the unfolded protein response in prostate cancer cells by antibody-directed against the carboxyl-terminal domain of GRP78.
abstract: Receptor-recognized forms of alpha(2)-macroglobulin (alpha(2)M*) bind to cancer cell surface GRP78, which functions as a signaling receptor promoting proliferation and survival. Patients with prostate, ovary, and skin cancer may develop auto-antibodies to the alpha(2)M* binding site which are receptor agonists whose presence indicates a poor prognosis. By contrast, antibodies directed against the COOH-terminal domain of GPR78 (anti-CTD antibody), are antagonists which down regulate pro-proliferative signaling and upregulate p53. Unfolded protein response (UPR) signaling plays an important role in cell survival and proliferation as well as apoptosis. We, therefore, studied the effect of anti-CTD antibody on UPR signaling in 1-LN and DU-145 prostate cancer cells. Treatment of these cells, which express GRP78 on their cell surface, with this antibody significantly downregulated IRE1-alpha, PERK, and ATF6alpha-dependent UPR signaling. By contrast, the pro-apoptotic protein GADD153 was elevated. Anti-CTD antibody treatment also elevated apoptotic components, cleaved PARP-1, and Erdj5. In general, a two to threefold effect was observed for the parameters which were studied. These studies suggest that anti-CTD antibody induces growth inhibitory and pro-apoptotic effects by modulating UPR signaling in human prostate cancer cells.
authors.affiliation: Department of Pathology, Duke University Medical Center, Box 3712, Durham, NC 27710, USA.
authors.forename: U K
authors.initials: UK
authors.lastname: Misra
authors.forename: S V
authors.initials: SV
authors.lastname: Pizzo
mesh_terms: D000906:Antibodies / Q000276:immunology* / Q000494:pharmacology*; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D000072224:Bcl-2-Like Protein 11; D020169:Caspases / Q000378:metabolism; D045744:Cell Line, Tumor; D015536:Down-Regulation / Q000187:drug effects; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000473:pathology; D000091342:Endoplasmic Reticulum Chaperone BiP; D004789:Enzyme Activation / Q000187:drug effects; D015852:Eukaryotic Initiation Factor-2 / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000737:chemistry* / Q000276:immunology*; D006801:Humans; D015151:Immunoblotting; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D009363:Neoplasm Proteins / Q000378:metabolism; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051742:Transcription Factor CHOP / Q000378:metabolism; D056811:Unfolded Protein Response / Q000187:drug effects*; D015854:Up-Regulation / Q000187:drug effects; D019892:eIF-2 Kinase / Q000378:metabolism
chemical_list: D000906:Antibodies; D051017:Apoptosis Regulatory Proteins; D000072224:Bcl-2-Like Protein 11; D020169:Caspases; D000091342:Endoplasmic Reticulum Chaperone BiP; D015852:Eukaryotic Initiation Factor-2; D006360:Heat-Shock Proteins; D008565:Membrane Proteins; D009363:Neoplasm Proteins; D011065:Poly(ADP-ribose) Polymerases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D051742:Transcription Factor CHOP; D019892:eIF-2 Kinase; C000606775:BCL2L11 protein, human; C497249:DDIT3 protein, human; C000717247:HSPA5 protein, human