title: Identification of DU 145 prostate cancer cell proteins that bind to the carboxy-terminal peptide of human PTHrP in vitro.
abstract: Peptides spanning the range of human parathyroid hormone-related protein (PTHrP) have been shown to bind heat shock protein-70 expressed on the surface of cancer cells with cytoprotective consequences in vitro. The present study focused on identification of intracellular proteins that interact with the carboxy-terminal peptide of human PTHrP. Using affinity chromatography, we applied extracts of DU 145 prostate cancer cells over PTHrP (140-173)-Sepharose and eluted with 8 M urea. After concentration and electrophoresis, protein bands were excised and subjected to mass spectroscopy analyses. Proteins identified included those associated with protection from oxidative stress, DNA repair, protection from apoptosis, and proteins involved in membrane trafficking and cytoskeletal rearrangement. These novel protein-protein interactions further support the hypothesis that the carboxy-terminus of PTHrP plays a role in cell survival.
authors.affiliation: Department of Surgery, University of California, San Diego and Veterans Affairs San Diego Healthcare System, San Diego, CA 92161, USA.
authors.forename: John J
authors.initials: JJ
authors.lastname: Grzesiak
authors.forename: Douglas W
authors.initials: DW
authors.lastname: Burton
authors.forename: Leonard J
authors.initials: LJ
authors.lastname: Deftos
authors.forename: Michael
authors.initials: M
authors.lastname: Bouvet
mesh_terms: D019921:Biotinylation; D045744:Cell Line, Tumor; D002846:Chromatography, Affinity; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D044162:Parathyroid Hormone-Related Protein / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry; D011471:Prostatic Neoplasms / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D018840:HSP70 Heat-Shock Proteins; D044162:Parathyroid Hormone-Related Protein; D010455:Peptides