1. Anti-tumor effects of toxins targeted to the prostate specific membrane antigen.
- Author
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Fracasso G, Bellisola G, Cingarlini S, Castelletti D, Prayer-Galetti T, Pagano F, Tridente G, and Colombatti M
- Subjects
- Antibodies, Monoclonal therapeutic use, Bone Neoplasms secondary, Carboxypeptidases immunology, Glutamate Carboxypeptidase II, Humans, Immunotoxins immunology, Male, Ricin administration & dosage, Tumor Cells, Cultured, Antigens, Surface, Carboxypeptidases pharmacology, Carcinoma pathology, Immunotoxins pharmacology, Prostatic Neoplasms pathology, Ricin pharmacology
- Abstract
Background: There is presently no effective therapy for relapsing, metastatic, androgen-independent prostate cancer. Immunotherapy with monoclonal antibody-vehicled toxins (Immunotoxins, ITs) may be a promising novel treatment option for the management of prostate cancer in these cases., Methods: Three anti-prostate specific membrane antigen (anti-PSMA) monoclonals (J591, PEQ226.5, and PM2P079.1) were cross-linked to ricin A-chain (RTA; native or recombinant), and their cytotoxic effects were investigated in monolayer and three-dimensional (3-D) cell cultures of prostate carcinoma cells (LNCaP)., Results: The various Immunotoxins showed effects in the nanomolar range (IC(50s) of 1.6-99 ng/ml) against PSMA+ cells (IC(50) being the concentration inhibiting 50% cell proliferation or protein synthesis). PSMA(-) cell lines were 62- to 277-fold less sensitive to anti-PSMA ITs, evidencing an appreciable therapeutic window. Treatment with J591-smpt-nRTA (0.35-31.7ng/ml) resulted in complete eradication of 3-D tumor micromasses or in 1.46- to 0.35-log reduction of target cells number, depending on the dose., Conclusion: Anti-PSMA ITs appear to be promising for use in the eradication of small prostate tumor cell aggregates present in tissues and in the bone marrow., (Copyright 2002 Wiley-Liss, Inc.)
- Published
- 2002
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