title: Identification of transmembrane protein in prostate cancer by the Escherichia coli ampicillin secretion trap: expression of CDON is involved in tumor cell growth and invasion.
abstract: OBJECTIVE
  Prostate cancer (PCa) is one of the most common malignancies worldwide. Genes expressed only in cancer tissue, and especially related to proteins located on the cell membrane, will be useful molecular markers for diagnosis and may also be good therapeutic targets. The aim of this study was to identify genes that encode transmembrane proteins present in PCa.
  
  
  RESULTS
  We generated Escherichia coli ampicillin secretion trap (CAST) libraries from 2 PCa cell lines and normal prostate tissues. By sequencing 3,264 colonies from CAST libraries, we identified 18 candidate genes that encode transmembrane proteins present in PCa. Quantitative RT-PCR analysis of these candidates revealed that STEAP1, ADAM9 and CDON were expressed much more highly in PCa than in 15 kinds of normal tissues. Among the candidates, CDON encodes the CDO protein, which is an orphan cell surface receptor of the immunoglobulin superfamily. Additional quantitative RT-PCR revealed that 83% of PCa tissues showed CDON overexpression. Knockdown of CDON in DU145 cells induced 5-fluorouracil-induced apoptosis and inhibited invasion ability.
  
  
  CONCLUSIONS
  These results suggest that CDON has a high potential as a therapeutic target for PCa.
authors.affiliation: Department of Molecular Pathology, Hiroshima University Graduate School of Biomedical Sciences, Hiroshima, Japan.
authors.forename: Tetsutaro
authors.initials: T
authors.lastname: Hayashi
authors.forename: Naohide
authors.initials: N
authors.lastname: Oue
authors.forename: Naoya
authors.initials: N
authors.lastname: Sakamoto
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Anami
authors.forename: Htoo Zarni
authors.initials: HZ
authors.lastname: Oo
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Sentani
authors.forename: Shinya
authors.initials: S
authors.lastname: Ohara
authors.forename: Jun
authors.initials: J
authors.lastname: Teishima
authors.forename: Akio
authors.initials: A
authors.lastname: Matsubara
authors.forename: Wataru
authors.initials: W
authors.lastname: Yasui
mesh_terms: D000667:Ampicillin; D000900:Anti-Bacterial Agents; D014408:Biomarkers, Tumor / Q000032:analysis*; D015153:Blotting, Western; D015815:Cell Adhesion Molecules / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli; D020869:Gene Expression Profiling; D015723:Gene Library; D005821:Genetic Techniques; D006801:Humans; D008297:Male; D009361:Neoplasm Invasiveness / Q000235:genetics* / Q000473:pathology; D011471:Prostatic Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D060888:Real-Time Polymerase Chain Reaction; D025521:Tumor Suppressor Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D014408:Biomarkers, Tumor; C107286:CDON protein, human; D015815:Cell Adhesion Molecules; D025521:Tumor Suppressor Proteins; D000667:Ampicillin