BACKGROUND: Prostate specific membrane antigen (PSMA), also called glutamate carboxypeptidase II (GCPII), is a target enzyme for diagnosis and treatment of prostate cancer. Moreover, it is upregulated in the vasculature of most solid tumors and is therefore a potential target for the generation of novel antineoplastics. In this context, we analyze the possibility of using rat and pig as animal models for enzymologic and in vivo studies. METHODS: We prepared the recombinant extracellular part of human, rat, and pig GCPII in S2 cell media and characterized the activity and inhibition profiles of the three orthologs by radioenzymatic assay. We performed Western blot analysis of GCPII expression in human, rat, and pig tissues using the monoclonal antibody GCP-04 and confirmed these findings by activity measurements and immunohistochemistry. RESULTS: The three recombinant proteins show similar specific enzymatic activities and inhibition profiles. Tissue expression analysis revealed that most of the pig and human tissues show at least some GCPII-positivity, while the expression pattern in rat is more restricted. Moreover, tissues such as prostate and testes exhibit different GCPII expression levels among the species studied. CONCLUSIONS: The rat and pig orthologs of GCPII seem to be suitable to approximate human GCPII in enzymologic studies. However, the diffuse expression pattern of GCPII in animal and human tissues could be a caveat for the potential utilization of GCPII-targeted anticancer drugs. Furthermore, variations in GCPII tissue distribution among the species studied should be considered when using rat or pig as models for antineoplastic drug discovery.

Gilead Sciences and IOCB Research Centre Institute of Organic Chemistry and Biochemistry Academy of Sciences of the Czech Republic Prague 6 Czech Republic

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Uncovering the essential roles of glutamate carboxypeptidase 2 orthologs in Caenorhabditis elegans

Characterization of glutamate carboxypeptidase 2 orthologs in trematodes

Glycoforms of human prostate-specific membrane antigen (PSMA) in human cells and prostate tissue

Structural basis of prostate-specific membrane antigen recognition by the A9g RNA aptamer

Mouse glutamate carboxypeptidase II (GCPII) has a similar enzyme activity and inhibition profile but a different tissue distribution to human GCPII

Novel Monoclonal Antibodies Recognizing Human Prostate-Specific Membrane Antigen (PSMA) as Research and Theranostic Tools

Structural and biochemical characterization of a novel aminopeptidase from human intestine

Development of a high-throughput fluorescence polarization assay to identify novel ligands of glutamate carboxypeptidase II

Glutamate carboxypeptidase II in diagnosis and treatment of neurologic disorders and prostate cancer