INTRODUCTION: In this study, a structurally modified phosphoramidate scaffold, with improved prostate-specific membrane antigen (PSMA) avidity, stability and in vivo characteristics, as a PET imaging agent for prostate cancer (PCa), was prepared and evaluated. METHODS: p-Fluorobenzoyl-aminohexanoate and 2-(3-hydroxypropyl)glycine were introduced into the PSMA-targeting scaffold yielding phosphoramidate 5. X-ray crystallography was performed on the PSMA/5 complex. [(18)F]5 was synthesized, and cell uptake and internalization studies were conducted in PSMA(+) LNCaP and CWR22Rv1 cells and PSMA(-) PC-3 cells. In vivo PET imaging and biodistribution studies were performed at 1 and 4 h post injection in mice bearing CWR22Rv1 tumor, with or without blocking agent. RESULTS: The crystallographic data showed interaction of the p-fluorobenzoyl group with an arene-binding cleft on the PSMA surface. In vitro studies revealed elevated uptake of [(18)F]5 in PSMA(+) cells (2.2% in CWR22Rv1 and 12.1% in LNCaP) compared to PSMA(-) cells (0.08%) at 4 h. In vivo tumor uptake of 2.33% ID/g and tumor-to-blood ratio of 265:1 was observed at 4 h. CONCLUSIONS: We have successfully synthesized, radiolabeled and evaluated a new PSMA-targeted PET agent. The crystal structure of the PSMA/5 complex highlighted the interactions within the arene-binding cleft contributing to the overall complex stability. The high target uptake and rapid non-target clearance exhibited by [(18)F]5 in PSMA(+) xenografts substantiates its potential use for PET imaging of PCa. ADVANCES IN KNOWLEDGE: The only FDA-approved imaging agent for PCa, Prostascint®, targets PSMA but suffers from inherent shortcomings. The data acquired in this manuscript confirmed that our new generation of [(18)F]-labeled PSMA inhibitor exhibited promising in vivo performance as a PET imaging agent for PCa and is well-positioned for subsequent clinical trials. Implications for Patient Care Our preliminary data demonstrate that this tracer possesses the required imaging characteristics to be sensitive and specific for PCa imaging in patients at all stages of the disease.

• MeSH
• amidy chemie   MeSH
• antigeny povrchové chemie   MeSH
• biologický transport MeSH
• glutamátkarboxypeptidasa II antagonisté a inhibitory   chemie   MeSH
• inhibiční koncentrace 50 MeSH
• inhibitory proteas chemie   metabolismus   farmakokinetika   farmakologie   MeSH
• izotopové značení MeSH
• konformace proteinů MeSH
• kyseliny fosforečné chemie   MeSH
• lidé MeSH
• molekulární modely MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• nádory prostaty patologie   MeSH
• peptidomimetika chemie   metabolismus   farmakokinetika   farmakologie   MeSH
• pozitronová emisní tomografie metody   MeSH
• radioizotopy fluoru * MeSH
• stabilita léku MeSH
• tkáňová distribuce MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

A series of O-phenyl methyl-, ethyl- and benzylalanyl phosphoramidate pronucleotides derived from cytostatic 6-aryl-7-deazapurine ribonucleosides were prepared by the cross-coupling reactions of the 2',3'-isopropylidene protected 6-chloro-7-deazapurine ribonucleoside phosphoramidates with (het)arylboronic acids or -stannanes followed by deprotection. Most of the prepared prodrugs exerted in vitro cytostatic effects against both solid tumor and lymphoid cancer cells within low micromolar range of concentrations. These activities were in general weaker or comparable to the activities of the parent nucleosides. Additional testing of selected prodrugs suggests that the lack of activity improvement over parent nucleosides is not due to the lack of permeability or inefficient catabolism of alanyl-ester by intracellular hydrolases. More likely, active efflux of prodrugs may play a role in their weak cytotoxic activity.

• MeSH
• hmotnostní spektrometrie s elektrosprejovou ionizací MeSH
• lidé MeSH
• magnetická rezonanční spektroskopie MeSH
• nádorové buněčné linie MeSH
• protinádorové látky chemie   farmakologie   MeSH
• purinové nukleosidy chemie   farmakologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

We have developed a robust solid-phase protocol which allowed the synthesis of chimeric oligonucleotides modified with phosphodiester and O-methylphosphonate linkages as well as their P-S and P-N variants. The novel O-methylphosphonate-derived modifications were obtained by oxidation, sulfurization, and amidation of the O-methyl-(H)-phosphinate internucleotide linkage introduced into the oligonucleotide chain by H-phosphonate chemistry using nucleoside-O-methyl-(H)-phosphinates as monomers. The H-phosphonate coupling followed by oxidation after each cycle enabled us to successfully combine H-phosphonate and phosphoramidite chemistries to synthesize diversely modified oligonucleotide strands.

• MeSH
• amidy chemie   MeSH
• dimerizace MeSH
• fosfáty chemie   MeSH
• fosforothioátové oligonukleotidy chemická syntéza   MeSH
• kyseliny fosforečné chemie   MeSH
• molekulární struktura MeSH
• oligonukleotidy chemická syntéza   chemie   MeSH
• techniky syntézy na pevné fázi * MeSH
• Publikační typ
• časopisecké články MeSH

A series of phosphoramidate-based prostate specific membrane antigen (PSMA) inhibitors of increasing lipophilicity were synthesized (4, 5, and 6), and their fluorine-18 analogs were evaluated for use as positron emission tomography (PET) imaging agents for prostate cancer. To gain insight into their modes of binding, they were also cocrystallized with the extracellular domain of PSMA. All analogs exhibited irreversible binding to PSMA with IC50 values ranging from 0.4 to 1.3 nM. In vitro assays showed binding and rapid internalization (80-95%, 2 h) of the radiolabeled ligands in PSMA(+) cells. In vivo distribution demonstrated significant uptake in CWR22Rv1 (PSMA(+)) tumor, with tumor to blood ratios of 25.6:1, 63.6:1, and 69.6:1 for [(18)F]4, [(18)F]5, and [(18)F]6, respectively, at 2 h postinjection. Installation of aminohexanoic acid (AH) linkers in the phosphoramidate scaffold improved their PSMA binding and inhibition and was critical for achieving suitable in vivo imaging properties, positioning [(18)F]5 and [(18)F]6 as favorable candidates for future prostate cancer imaging clinical trials.

• MeSH
• amidy chemická syntéza   chemie   farmakologie   MeSH
• antigeny povrchové MeSH
• experimentální nádory diagnostické zobrazování   MeSH
• glutamátkarboxypeptidasa II antagonisté a inhibitory   MeSH
• kyseliny fosforečné chemická syntéza   chemie   farmakologie   MeSH
• lidé MeSH
• molekulární modely MeSH
• molekulární struktura MeSH
• myši nahé MeSH
• myši MeSH
• nádorové buňky kultivované MeSH
• nádory prostaty diagnostické zobrazování   MeSH
• peptidomimetika chemická syntéza   chemie   farmakologie   MeSH
• pozitronová emisní tomografie * MeSH
• radioizotopy fluoru MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

• Publikační typ
• abstrakty MeSH

• MeSH
• aminopterin farmakologie   MeSH
• DNA chemie   MeSH
• protinádorové látky farmakologie   MeSH
• thymus chemie   MeSH

Parasites of the Plasmodium genus are unable to produce purine nucleotides de novo and depend completely on the salvage pathway. This fact makes plasmodial hypoxanthine-guanine-(xanthine) phosphoribosyltransferase [HG(X)PRT] a valuable target for development of antimalarial agents. A series of nucleotide analogues was designed, synthesized and evaluated as potential inhibitors of Plasmodium falciparum HGXPRT, P. vivax HGPRT and human HGPRT. These novel nucleoside phosphonates have a pyrrolidine, piperidine or piperazine ring incorporated into the linker connecting the purine base to a phosphonate group(s) and exhibited a broad range of Ki values between 0.15 and 72 μM. The corresponding phosphoramidate prodrugs, able to cross cell membranes, have been synthesized and evaluated in a P. falciparum infected human erythrocyte assay. Of the eight prodrugs evaluated seven exhibited in vitro antimalarial activity with IC50 values within the range of 2.5-12.1 μM. The bis-phosphoramidate prodrug 13a with a mean (SD) IC50 of 2.5 ± 0.7 μM against the chloroquine-resistant P. falciparum W2 strain exhibited low cytotoxicity in the human hepatocellular liver carcinoma (HepG2) and normal human dermal fibroblasts (NHDF) cell lines at a concentration of 100 μM suggesting good selectivity for further structure-activity relationship investigations.

• MeSH
• antimalarika chemická syntéza   metabolismus   farmakologie   MeSH
• buněčné linie MeSH
• erytrocyty cytologie   metabolismus   parazitologie   MeSH
• inhibitory enzymů chemie   metabolismus   MeSH
• léková rezistence účinky léků   MeSH
• lidé MeSH
• nukleotidy chemie   metabolismus   MeSH
• pentosyltransferasy antagonisté a inhibitory   metabolismus   MeSH
• piperazin chemie   MeSH
• piperidiny chemie   MeSH
• Plasmodium falciparum účinky léků   enzymologie   MeSH
• Plasmodium vivax enzymologie   MeSH
• preklinické hodnocení léčiv MeSH
• prekurzory léčiv chemická syntéza   chemie   metabolismus   farmakologie   MeSH
• protozoální proteiny antagonisté a inhibitory   metabolismus   MeSH
• pyrrolidiny chemie   MeSH
• viabilita buněk účinky léků   MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

UNLABELLED: Inhibitors targeting human glutamate carboxypeptidase II (GCPII) typically consist of a P1' glutamate-derived binding module, which warrants the high affinity and specificity, linked to an effector function that is positioned within the entrance funnel of the enzyme. Here we present a comprehensive structural and computational study aimed at dissecting the importance of the effector function for GCPII binding and affinity. To this end we determined crystal structures of human GCPII in complex with a series of phosphoramidate-based inhibitors harboring effector functions of diverse physicochemical characteristics. Our data show that higher binding affinities of phosphoramidates, compared to matching phosphonates, are linked to the presence of additional hydrogen bonds between Glu424 and Gly518 of the enzyme and the amide group of the phosphoramidate. While the positioning of the P1' glutamate-derived module within the S1' pocket of GCPII is invariant, interaction interfaces between effector functions and residues lining the entrance funnel are highly varied, with the positively charged arginine patch defined by Arg463, Arg534 and Arg536 being the only 'hot-spot' common to several studied complexes. This variability stems in part from the fact that the effector/GCPII interfaces generally encompass isolated areas of nonpolar residues within the entrance funnel and resulting van der Waals contacts lack the directionality typical for hydrogen bonding interactions. The presented data unravel a complexity of binding modes of inhibitors within non-prime site(s) of GCPII and can be exploited for the design of novel GCPII-specific compounds. PDB ID CODES: Atomic coordinates of the present structures together with the experimental structure factor amplitudes were deposited at the RCSB Protein Data Bank under accession codes 4P44 (complex with JRB-4-81), 4P45 (complex with JRB-4-73), 4P4B (complex with CTT54), 4P4D (complex with MP1C), 4P4E (complex with MP1D), 4P4F (complex with NC-2-40), 4P4I (complex with T33) and 4P4J (complex with T33D).

• MeSH
• amidy chemická syntéza   chemie   farmakologie   MeSH
• antigeny povrchové metabolismus   MeSH
• glutamátkarboxypeptidasa II antagonisté a inhibitory   metabolismus   MeSH
• inhibitory enzymů chemická syntéza   chemie   farmakologie   MeSH
• krystalografie rentgenová MeSH
• kyseliny fosforečné chemická syntéza   chemie   farmakologie   MeSH
• lidé MeSH
• molekulární modely MeSH
• molekulární struktura MeSH
• racionální návrh léčiv * MeSH
• vodíková vazba MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

We report on the synthesis of novel conformationally locked nucleoside and nucleotide derivatives, which are structurally closely related to clinically used antivirals such as didanosine and abacavir. As a suitable conformationally rigid substitute of the sugar/pseudosugar ring allowing a permanent stabilization of the nucleoside in North conformation we employed bicyclo[2.2.1]heptane (norbornane) substituted in the bridgehead position with a hydroxymethyl group and in the C-3 position with a nucleobase. Prepared nucleoside derivatives were also converted into appropriate phosphoramidate prodrugs (ProTides) in order to increase delivery of the compounds in the cells. All target compounds were evaluated in a broad antiviral and cytostatic assay panel.

• MeSH
• antivirové látky chemická syntéza   MeSH
• konformace nukleové kyseliny MeSH
• lidé MeSH
• norbornany chemická syntéza   chemie   MeSH
• nukleosidy chemická syntéza   chemie   MeSH
• nukleotidy chemická syntéza   chemie   MeSH
• stereoizomerie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The synthesis and biological activity profiling of a large series of diverse pyrrolo[2,3-d]pyrimidine 4'-C-methylribonucleosides bearing an (het)aryl group at position 4 or 5 is reported as well as the synthesis of several phosphoramidate prodrugs. These compounds are 4'-C-methyl derivatives of previously reported cytostatic hetaryl-7-deazapurine ribonucleosides. The synthesis is based on glycosylation of halogenated 7-deazapurine bases with 1,2-di-O-acetyl-3,5-di-O-benzyl-4-C-methyl-β-d-ribofuranose followed by cross-coupling and nucleophilic substitution reactions. The final compounds showed low cytotoxicity and several derivatives exerted antiviral activity against HCV or Dengue viruses at micromolar concentrations.

• MeSH
• antivirové látky chemická syntéza   farmakologie   MeSH
• Hepacivirus účinky léků   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• prekurzory léčiv chemická syntéza   farmakologie   MeSH
• protinádorové látky chemická syntéza   farmakologie   MeSH
• purinové nukleosidy chemická syntéza   farmakologie   MeSH
• purinové nukleotidy chemická syntéza   farmakologie   MeSH
• virus dengue účinky léků   MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH