title: Preclinical evaluation of a recombinant anti-prostate specific membrane antigen single-chain immunotoxin against prostate cancer.
abstract: The prostate-specific membrane antigen (PSMA) is abundantly expressed on prostate cancer epithelial cells and its expression correlates with tumor progression. Therefore, a specific immunotherapy against this antigen may be a novel therapeutic option for the management of prostate cancer. We generated an anti-PSMA single-chain antibody fragment (scFv), called D7, by phage display from the monoclonal antibody 3/F11. By C-terminal ligation of the toxic domain of Pseudomonas Exotoxin A (PE40) to the genes of D7, the immunotoxin D7-PE40 was generated. D7 and D7-PE40 specifically bound to PSMA transfectants and to the PSMA expressing prostate cancer cell line C4-2. In addition, D7-PE40 showed a high serum stability and induced a 50% reduction of viability (IC50) in C4-2 cells at a concentration of 140 pM. In vivo, D7-PE40 was well tolerated in SCID mice up to a single dose of 20 microg, whereas higher doses induced severe hepatotoxicity with deaths of the animals. Immunotoxin treatment of mice bearing C4-2 tumor xenografts caused a significant inhibition of tumor growth, whereas mice with PSMA-negative DU 145 tumors remained unaffected. Owing to its high and specific cytotoxicity and its capability to inhibit prostate tumor growth in vivo the immunotoxin D7-PE40 represents a promising candidate for the immunotherapy of prostate cancer.
authors.affiliation: Department of Urology, University Hospital Freiburg, Germany. philipp.wolf@uniklinik-freiburg.de
authors.forename: Philipp
authors.initials: P
authors.lastname: Wolf
authors.forename: Karen
authors.initials: K
authors.lastname: Alt
authors.forename: David
authors.initials: D
authors.lastname: Wetterauer
authors.forename: Patrick
authors.initials: P
authors.lastname: Bühler
authors.forename: Dorothee
authors.initials: D
authors.lastname: Gierschner
authors.forename: Arndt
authors.initials: A
authors.lastname: Katzenwadel
authors.forename: Ulrich
authors.initials: U
authors.lastname: Wetterauer
authors.forename: Ursula
authors.initials: U
authors.lastname: Elsässer-Beile
mesh_terms: D036002:ADP Ribose Transferases / Q000235:genetics / Q000276:immunology; D000818:Animals; D000954:Antigens, Surface / Q000235:genetics / Q000276:immunology*; D001427:Bacterial Toxins / Q000235:genetics / Q000276:immunology; D002460:Cell Line; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000276:immunology; D004354:Drug Screening Assays, Antitumor; D005098:Exotoxins / Q000235:genetics / Q000276:immunology; D043425:Glutamate Carboxypeptidase II / Q000235:genetics / Q000276:immunology*; D006801:Humans; D000922:Immunotoxins / Q000235:genetics / Q000276:immunology* / Q000494:pharmacology; D008297:Male; D051379:Mice; D016513:Mice, SCID; D011471:Prostatic Neoplasms / Q000276:immunology* / Q000473:pathology / Q000517:prevention & control; D011994:Recombinant Proteins / Q000276:immunology; D057127:Single-Chain Antibodies / Q000235:genetics / Q000276:immunology*; D047368:Tumor Burden / Q000187:drug effects; D037521:Virulence Factors / Q000235:genetics / Q000276:immunology; D023041:Xenograft Model Antitumor Assays; D000097668:Pseudomonas aeruginosa Exotoxin A
chemical_list: D036002:ADP Ribose Transferases; D000954:Antigens, Surface; D001427:Bacterial Toxins; D005098:Exotoxins; D043425:Glutamate Carboxypeptidase II; D000922:Immunotoxins; D011994:Recombinant Proteins; D057127:Single-Chain Antibodies; D037521:Virulence Factors; D000097668:Pseudomonas aeruginosa Exotoxin A; C473848:FOLH1 protein, human