title: A highly conserved protein secreted by the prostate cancer cell line PC-3 is expressed in benign and malignant prostate tissue.
abstract: In this study we characterize a novel gene on human chromosome 9 and its translation product, PC3-secreted microprotein (PSMP). The gene contains three exons that encode a protein of 139 amino acid residues, including a predicted signal peptide of 36 residues. The molecule is homologous to beta-microseminoprotein (MSP), a protein of unknown function, secreted at high concentration by the prostate gland. These two proteins have only 23% sequence identity, but their common origin is revealed by a preserved pattern of Cys residues. In contrast to MSP, which shows poor conservation between species, PSMP is very conserved. High transcript levels were detected in the prostate cancer cell line PC-3. Antiserum raised against PSMP detected a protein with an apparent molecular mass of 18 kDa in culture medium conditioned by PC-3 cells, but in cell lysates the antiserum also recognized a molecular species of 16 kDa, suggesting that PSMP undergoes post-translational modification. Xenografted PC-3 cell tumors in athymic nude mice showed strong staining for both PSMP protein and mRNA. Studies on human prostate cancer specimens showed immunohistochemical staining of both tumor and benign glandular cells. Our results suggest that PSMP is an important protein with significance in prostate cancer.
authors.affiliation: Lund University, Division of Clinical Chemistry, Department of Laboratory Medicine, University Hospital MAS, S-205 02 Malmö, Sweden.
authors.forename: Camilla
authors.initials: C
authors.lastname: Valtonen-André
authors.forename: Anders
authors.initials: A
authors.lastname: Bjartell
authors.forename: Rebecka
authors.initials: R
authors.lastname: Hellsten
authors.forename: Hans
authors.initials: H
authors.lastname: Lilja
authors.forename: Pirkko
authors.initials: P
authors.lastname: Härkönen
authors.forename: Ake
authors.initials: A
authors.lastname: Lundwall
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D006801:Humans; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000235:genetics* / Q000378:metabolism; D011467:Prostate / Q000166:cytology / Q000378:metabolism*; D011471:Prostatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D029584:Prostatic Secretory Proteins / Q000737:chemistry*; D051381:Rats; D017386:Sequence Homology, Amino Acid; D014407:Tumor Cells, Cultured
chemical_list: D009363:Neoplasm Proteins; D029584:Prostatic Secretory Proteins; C519082:MSMP protein, human; C043076:beta-microseminoprotein