Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0376358 (prostate cancer)
 59,338 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Imaging of glutamate carboxypeptidase II (GCP II), also known as N-acetylated alpha-linked L-amino dipeptidase (NAALADase), may enable study of glutamatergic transmission, prostate cancer, and tumor neovasculature in vivo. Our goal was to develop a probe for GCP II for use with positron emission tomography (PET). Radiosynthesis of 11C-MeCys-C(O)-Glu or 11C-(S)-2-[3-((R)-1-carboxy-2-methylsulfanyl-ethyl)-ureido]-pentanedioic acid (11C-MCG), an asymmetric urea and potent (Ki = 1.9 nM) inhibitor of GCP II, was performed by C-11 methylation of the free thiol. Biodistribution of 11C-MCG was assayed in mice, and quantitative PET was performed in a baboon. 11C-MCG was obtained in 16% radiochemical yield at the end of synthesis with specific radioactivities over 167 GBq/mmol (4000 Ci/mmol) within 30 min after the end of bombardment. At 30 min postinjection, 11C-MCG showed 33.0 +/- 5.1%, 0.4 +/- 0.1%, and 1.1 +/- 0.2% ID/g in mouse kidney (target tissue), muscle, and blood, respectively. Little radioactivity gained access to the brain. Blockade with unlabeled MCG or 2-(phosphonomethyl)pentanedioic acid (PMPA), another potent inhibitor of GCP II, provided sevenfold and threefold reductions, respectively, in binding to target tissue. For PET, distribution volumes (DVs) were 1.38 then 0.87 pre- and postblocker (PMPA). Little metabolism of 11C-MCG occurred in the mouse or baboon. These results suggest that 11C-MCG may be useful for imaging GCP II in the periphery.
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PMID:11C-MCG: synthesis, uptake selectivity, and primate PET of a probe for glutamate carboxypeptidase II (NAALADase). 1292 Aug 50

Prostate-Specific Membrane Antigen (PSMA) is a glutamate carboxypeptidase II that is highly expressed by both normal and malignant prostate epithelial cells and by the neovasculature of many tumor types but is not expressed by endothelial cells in normal tissue. PSMA possesses the hydrolytic properties of an N-acetylated alpha-linked acidic dipeptidase (NAALADase) and also functions as a pteroyl poly-gamma-glutamyl carboxypeptidase (i.e., folate hydrolase). Therefore, PSMA can be targeted for activation of peptide-based prodrugs within the extracellular fluid of prostate cancers. In this study, methotrexate-based peptide analogs were evaluated to identify PSMA selective substrates that are also stable to nonspecific hydrolysis in human and mouse plasma. These methotrexate analogs were also characterized for in vitro toxicity against PSMA and nonPSMA producing human cancer cell lines. Analogs containing gamma-linked glutamate residues were most efficiently hydrolyzed by PSMA, but were unstable in plasma. Analogs containing both alpha- and gamma-linked acidic amino acids were less efficiently hydrolyzed by PSMA but were most stable in plasma. Analogs were 5-10 fold more selectively toxic in vitro in the presence of active PSMA. These studies have identified PSMA selective, plasma stable peptide substrates that can be incorporated into prodrugs targeted for activation by PSMA within prostate cancer sites.
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PMID:Use of methotrexate-based peptide substrates to characterize the substrate specificity of prostate-specific membrane antigen (PSMA). 1515 2

Human glutamate carboxypeptidase II (GCPII) is a co-catalytic metallopeptidase and its putative catalytic domain is homologous to the aminopeptidases from Vibrio proteolyticus and Streptomyces griseus. In humans, the enzyme is expressed predominantly in the nervous system and the prostate. The prostate form, termed prostate-specific membrane antigen, is overexpressed in prostate cancer and is used as a diagnostic marker of the disease. Inhibition of the form of GCPII expressed in the central nervous system has been shown to protect against ischemic injury in experimental animal models. Human GCPII consists of 750 amino acids, and six individual domains were predicted to constitute the protein structure. Here, we report the analysis of the contribution of these putative domains to the structure/function of recombinant human GCPII. We cloned 13 mutants of human GCPII that are truncated or extended at one or both the N- and C-termini of the GCPII sequence. The clones were used to generate stably transfected Drosophila Schneider's cells, and the expression and carboxypeptidase activities of the individual protein products were determined. The extreme C-terminal region of human GCPII was found to be critical for the hydrolytic activity of the enzyme. The deletion of as few as 15 amino acids from the C-terminus was shown to completely abolish the enzymatic activity of GCPII. Furthermore, the GCPII carboxypeptidase activity was abrogated upon removal of more than 60 amino acid residues from the N-terminus of the protein. Overall, these results clearly show that amino acid segments at the N- and C-termini of the ectodomain of GCPII are essential for its carboxypeptidase activity and/or proper folding.
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PMID:Amino acids at the N- and C-termini of human glutamate carboxypeptidase II are required for enzymatic activity and proper folding. 1520 43

Membrane-bound glutamate carboxypeptidase II (GCPII) is a zinc metalloenzyme that catalyzes the hydrolysis of the neurotransmitter N-acetyl-L-aspartyl-L-glutamate (NAAG) to N-acetyl-L-aspartate and L-glutamate (which is itself a neurotransmitter). Potent and selective GCPII inhibitors have been shown to decrease brain glutamate and provide neuroprotection in preclinical models of stroke, amyotrophic lateral sclerosis, and neuropathic pain. Here, we report crystal structures of the extracellular part of GCPII in complex with both potent and weak inhibitors and with glutamate, the product of the enzyme's hydrolysis reaction, at 2.0, 2.4, and 2.2 A resolution, respectively. GCPII folds into three domains: protease-like, apical, and C-terminal. All three participate in substrate binding, with two of them directly involved in C-terminal glutamate recognition. One of the carbohydrate moieties of the enzyme is essential for homodimer formation of GCPII. The three-dimensional structures presented here reveal an induced-fit substrate-binding mode of this key enzyme and provide essential information for the design of GCPII inhibitors useful in the treatment of neuronal diseases and prostate cancer.
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PMID:Structure of glutamate carboxypeptidase II, a drug target in neuronal damage and prostate cancer. 1646 55

Human glutamate carboxypeptidase II (GCPII) occurs in the central nervous system as well as in human prostate (where it is called prostate-specific membrane antigen; PSMA). Inhibitors of the enzyme have been shown to provide neuroprotection, but may also be useful for the detection, imaging and treatment of prostate cancer. Crystal structures were determined of the extracellular part of GCPII (amino-acid residues 44-750) in complex with two potent inhibitors, quisqualate and 2-PMPA (the strongest GCPII inhibitor to date), at resolutions of 3.0 and 2.2 A, respectively. In addition, models were constructed for binding of the inhibitors willardiine, homoibotenate, L-2-amino-4-phosphonobutanoic acid and L-serine-O-sulfate to the S1' site of the enzyme. The common denominator for high-affinity binding to the S1' site is the formation of two strong salt bridges.
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PMID:Human glutamate carboxypeptidase II inhibition: structures of GCPII in complex with two potent inhibitors, quisqualate and 2-PMPA. 1737 56

Human glutamate carboxypeptidase II [GCPII (EC 3.4.17.21)] is recognized as a promising pharmacological target for the treatment and imaging of various pathologies, including neurological disorders and prostate cancer. Recently reported crystal structures of GCPII provide structural insight into the organization of the substrate binding cavity and highlight residues implicated in substrate/inhibitor binding in the S1' site of the enzyme. To complement and extend the structural studies, we constructed a model of GCPII in complex with its substrate, N-acetyl-l-aspartyl-l-glutamate, which enabled us to predict additional amino acid residues interacting with the bound substrate, and used site-directed mutagenesis to assess the contribution of individual residues for substrate/inhibitor binding and enzymatic activity of GCPII. We prepared and characterized 12 GCPII mutants targeting the amino acids in the vicinity of substrate/inhibitor binding pockets. The experimental results, together with the molecular modeling, suggest that the amino acid residues delineating the S1' pocket of the enzyme (namely Arg210) contribute primarily to the high affinity binding of GCPII substrates/inhibitors, whereas the residues forming the S1 pocket might be more important for the 'fine-tuning' of GCPII substrate specificity.
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PMID:Mapping of the active site of glutamate carboxypeptidase II by site-directed mutagenesis. 1771 8

Urea-based, low molecular weight ligands of glutamate carboxypeptidase II (GCPII) have demonstrated efficacy in various models of neurological disorders and can serve as imaging agents for prostate cancer. To enhance further development of such compounds, we determined X-ray structures of four complexes between human GCPII and urea-based inhibitors at high resolution. All ligands demonstrate an invariant glutarate moiety within the S1' pocket of the enzyme. The ureido linkage between P1 and P1' inhibitor sites interacts with the active-site Zn(1)(2+) ion and the side chains of Tyr552 and His553. Interactions within the S1 pocket are defined primarily by a network of hydrogen bonds between the P1 carboxylate group of the inhibitors and the side chains of Arg534, Arg536, and Asn519. Importantly, we have identified a hydrophobic pocket accessory to the S1 site that can be exploited for structure-based design of novel GCPII inhibitors with increased lipophilicity.
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PMID:Interactions between human glutamate carboxypeptidase II and urea-based inhibitors: structural characterization. 1905 59

Glutamate carboxypeptidase III (GCPIII) is a metalloenzyme that belongs to the transferrin receptor/glutamate carboxypeptidase II (GCPII; EC 3.4.17.21) superfamily. GCPIII has been studied mainly because of its evolutionary relationship to GCPII, an enzyme involved in a variety of neuropathologies and malignancies, such as glutamatergic neurotoxicity and prostate cancer. Given the potential functional and pharmacological overlap between GCPIII and GCPII, studies addressing the structural and physiological properties of GCPIII are crucial for obtaining a deeper understanding of the GCPII/GCPIII system. In the present study, we report high-resolution crystal structures of the human GCPIII ectodomain in a 'pseudo-unliganded' state and in a complex with: (a) L-glutamate (a product of hydrolysis); (b) a phosphapeptide transition state mimetic, namely (2S,3'S)-{[(3'-amino-3'-carboxy-propyl)-hydroxyphosphinoyl]methyl}-pentanedioic acid; and (c) quisqualic acid, a glutamate biostere. Our data reveal the overall fold and quaternary arrangement of the GCPIII molecule, define the architecture of the GCPIII substrate-binding cavity, and offer an experimental evidence for the presence of Zn(2+) ions in the bimetallic active site. Furthermore, the structures allow us to detail interactions between the enzyme and its ligands and to characterize the functional flexibility of GCPIII, which is essential for substrate recognition. A comparison of these GCPIII structures with the equivalent GCPII complexes reveals differences in the organization of specificity pockets, in surface charge distribution, and in the occupancy of the co-catalytic zinc sites. The data presented here provide information that should prove to be essential for the structurally-aided design of GCPIII-specific inhibitors and might comprise guidelines for future comparative GCPII/GCPIII studies.
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PMID:Structural insight into the evolutionary and pharmacologic homology of glutamate carboxypeptidases II and III. 1967 40

In view of the pivotal role of glutamate carboxypeptidase II (GCPII) in carcinogenesis, its expression as prostate specific membrane antigen (PSMA) and folate hydrolase (FOLH1) may be influenced by its haplotypes, contributing to the etiology of prostate and breast cancer. To test this hypothesis, breast and prostate cancer cases and controls were subjected to whole gene screening of GCPII and correlated with plasma folate levels and PSMA expression. The impact of variants on a 3-dimensional structure of GCPII was explored by in silico studies. Six novel variations i.e. V108A, P160S, Y176H, D191V, G206R and G245S; and two known variations i.e. R190W and H475Y were identified in GCPII. All-wild haplotype and a haplotype harbouring D191V showed association with breast cancer risk while haplotypes harbouring V108A and P160S reduced the risk. Haplotypes with V108A and G245S variants showed increased risk for prostate cancer due to high PSMA expression while P160S conferred protection against prostate cancer. In silico studies suggests that P160S and R190W variants result in relaxed substrate binding facilitating either rapid catalysis or exchange of substrates and products in the active site which was substantiated by high plasma folate levels associated with these variants. On the contrary, D191V was associated with very low plasma folate levels despite having a high PSMA expression. This is the first comprehensive study examining variations in GCPII in relation to breast and prostate cancer risk. Changes in the plasma folate levels and changes in PSMA expression are associated with breast and prostate cancer risk respectively.
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PMID:Association of glutamate carboxypeptidase II (GCPII) haplotypes with breast and prostate cancer risk. 2326 99

N-acetyl-L-aspartyl-L-glutamate peptidase-like 2 (NAALADL2) is a member of the glutamate carboxypeptidase II family, best characterized by prostate-specific membrane antigen (PSMA/NAALAD1). Using immunohistochemistry (IHC), we have shown overexpression of NAALADL2 in colon and prostate tumours when compared with benign tissue. In prostate cancer, NAALADL2 expression was associated with stage and Grade, as well as circulating mRNA levels of the NAALADL2 gene. Overexpression of NAALADL2 was shown to predict poor survival following radical prostatectomy. In contrast to PSMA/NAALAD1, NAALADL2 was localized at the basal cell surface where it promotes adhesion to extracellular matrix proteins. Using stable knockdown and overexpression cell lines, we have demonstrated NAALADL2-dependent changes in cell migration, invasion and colony-forming potential. Expression arrays of the knockdown and overexpression cell lines have identified nine genes that co-expressed with NAALADL2, which included membrane proteins and genes known to be androgen regulated, including the prostate cancer biomarkers AGR2 and SPON2. Androgen regulation was confirmed in a number of these genes, although NAALADL2 itself was not found to be androgen regulated. NAALADL2 was also found to regulate levels of Ser133 phosphorylated C-AMP-binding protein (CREB), a master regulator of a number of cellular processes involved in cancer development and progression. In combination, these data suggest that changes in expression of NAALADL2 can impact upon a number of pro-oncogenic pathways and processes, making it a useful biomarker for both diagnosis and prognosis.
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PMID:N-acetyl-L-aspartyl-L-glutamate peptidase-like 2 is overexpressed in cancer and promotes a pro-migratory and pro-metastatic phenotype. 2424 Jun 87


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