All medically important unicellular protozoans cannot synthesize purines de novo and they entirely rely on the purine salvage pathway (PSP) for their nucleotide generation. Therefore, purine derivatives have been considered as a promising source of anti-parasitic compounds since they can act as inhibitors of the PSP enzymes or as toxic products upon their activation inside of the cell. Here, we characterized a Trypanosoma brucei enzyme involved in the salvage of adenine, the adenine phosphoribosyl transferase (APRT). We showed that its two isoforms (APRT1 and APRT2) localize partly in the cytosol and partly in the glycosomes of the bloodstream form (BSF) of the parasite. RNAi silencing of both APRT enzymes showed no major effect on the growth of BSF parasites unless grown in artificial medium with adenine as sole purine source. To add into the portfolio of inhibitors for various PSP enzymes, we designed three types of acyclic nucleotide analogs as potential APRT inhibitors. Out of fifteen inhibitors, four compounds inhibited the activity of the recombinant APRT1 with Ki in single µM values. The ANP phosphoramidate membrane-permeable prodrugs showed pronounced anti-trypanosomal activity in a cell-based assay, despite the fact that APRT enzymes are dispensable for T. brucei growth in vitro. While this suggests that the tested ANP prodrugs exert their toxicity by other means in T. brucei, the newly designed inhibitors can be further improved and explored to identify their actual target(s).

• MeSH
• adeninfosforibosyltransferasa metabolismus   MeSH
• adeninnukleotidy metabolismus   MeSH
• buněčné linie MeSH
• HeLa buňky MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• nukleosidy metabolismus   MeSH
• organofosfonáty metabolismus   MeSH
• puriny metabolismus   MeSH
• Trypanosoma brucei brucei metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• adeninfosforibosyltransferasa MeSH
• adeninnukleotidy MeSH
• nukleosidy MeSH
• organofosfonáty MeSH
• purine MeSH Prohlížeč
• puriny MeSH

Helicobacter pylori (Hp) is a human pathogen that lives in the gastric mucosa of approximately 50% of the world's population causing gastritis, peptic ulcers, and gastric cancer. An increase in resistance to current drugs has sparked the search for new Hp drug targets and therapeutics. One target is the disruption of nucleic acid production, which can be achieved by impeding the synthesis of 6-oxopurine nucleoside monophosphates, the precursors of DNA and RNA. These metabolites are synthesized by Hp xanthine-guanine-hypoxanthine phosphoribosyltransferase (XGHPRT). Here, nucleoside phosphonates have been evaluated, which inhibit the activity of this enzyme with Ki values as low as 200 nM. The prodrugs of these compounds arrest the growth of Hp at a concentration of 50 μM in cell-based assays. The kinetic properties of HpXGHPRT have been determined together with its X-ray crystal structure in the absence and presence of 9-[(N-3-phosphonopropyl)-aminomethyl-9-deazahypoxanthine, providing a basis for new antibiotic development.

• MeSH
• antibakteriální látky chemie   metabolismus   farmakologie   terapeutické užití   MeSH
• bakteriální proteiny chemie   metabolismus   MeSH
• gastrointestinální nemoci farmakoterapie   mikrobiologie   patologie   MeSH
• Helicobacter pylori účinky léků   enzymologie   MeSH
• hypoxanthinfosforibosyltransferasa chemie   metabolismus   MeSH
• hypoxanthiny chemie   metabolismus   farmakologie   terapeutické užití   MeSH
• infekce vyvolané Helicobacter pylori farmakoterapie   patologie   MeSH
• kinetika MeSH
• krystalografie rentgenová MeSH
• lidé MeSH
• organofosfonáty chemie   metabolismus   farmakologie   terapeutické užití   MeSH
• pentosyltransferasy chemie   metabolismus   MeSH
• prekurzory léčiv chemie   metabolismus   farmakologie   terapeutické užití   MeSH
• sekvence aminokyselin MeSH
• sekvenční seřazení MeSH
• simulace molekulární dynamiky MeSH
• vazebná místa MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 9-deazahypoxanthine MeSH Prohlížeč
• antibakteriální látky MeSH
• bakteriální proteiny MeSH
• hypoxanthine-guanine-xanthine phosphoribosyltransferase MeSH Prohlížeč
• hypoxanthinfosforibosyltransferasa MeSH
• hypoxanthiny MeSH
• organofosfonáty MeSH
• pentosyltransferasy MeSH
• prekurzory léčiv MeSH

PURPOSE: Skin permeation/penetration enhancers are substances that enable drug delivery through or into the skin. METHODS: To search for new enhancers with high but reversible activity and acceptable toxicity, we synthesized a series of D-glucose derivatives, both hydrophilic and amphiphilic. RESULTS: Initial evaluation of the ability of these sugar derivatives to increase permeation and penetration of theophylline through/into human skin compared with a control (no enhancer) or sorbitan monolaurate (Span 20; positive control) revealed dodecyl 6-amino-6-deoxy-α-D-glucopyranoside 5 as a promising enhancer. Furthermore, this amino sugar 5 increased epidermal concentration of a highly hydrophilic antiviral cidofovir by a factor of 7. The effect of compound 5 on skin electrical impedance suggested its direct interaction with the skin barrier. Infrared spectroscopy of isolated stratum corneum revealed no effect of enhancer 5 on the stratum corneum proteins but an overall decrease in the lipid chain order. The enhancer showed acceptable toxicity on HaCaT keratinocyte and 3T3 fibroblast cell lines. Finally, transepidermal water loss returned to baseline values after enhancer 5 had been removed from the skin. CONCLUSIONS: Compound 5, a dodecyl amino glucoside, is a promising enhancer that acts through a reversible interaction with the stratum corneum lipids.

• Klíčová slova
• penetration enhancers, sugar, topical drug delivery, transdermal drug delivery,
• MeSH
• antivirové látky aplikace a dávkování   metabolismus   MeSH
• aplikace kožní MeSH
• aplikace lokální MeSH
• buněčné linie MeSH
• cidofovir MeSH
• cytosin aplikace a dávkování   analogy a deriváty   metabolismus   MeSH
• epidermis účinky léků   metabolismus   MeSH
• farmaceutická chemie MeSH
• glukosidy chemická syntéza   farmakologie   MeSH
• hexosy farmakologie   MeSH
• hydrofobní a hydrofilní interakce MeSH
• keratinocyty účinky léků   metabolismus   MeSH
• kožní absorpce MeSH
• kůže účinky léků   metabolismus   MeSH
• lékové transportní systémy MeSH
• lidé MeSH
• lipidy fyziologie   MeSH
• organofosfonáty aplikace a dávkování   metabolismus   MeSH
• permeabilita MeSH
• theofylin aplikace a dávkování   metabolismus   MeSH
• viabilita buněk MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antivirové látky MeSH
• cidofovir MeSH
• cytosin MeSH
• glukosidy MeSH
• hexosy MeSH
• lipidy MeSH
• organofosfonáty MeSH
• sorbitan monolaurate MeSH Prohlížeč
• theofylin MeSH

Human tuberculosis is a chronic infectious disease affecting millions of lives. Because of emerging resistance to current medications, new therapeutic drugs are needed. One potential new target is hypoxanthine-guanine phosphoribosyltransferase (MtHGPRT), a key enzyme of the purine salvage pathway. Here, newly synthesized acyclic nucleoside phosphonates (ANPs) have been shown to be competitive inhibitors of MtHGPRT with Ki values as low as 0.69 μM. Prodrugs of these compounds arrest the growth of a virulent strain of M. tuberculosis with MIC50 values as low as 4.5 μM and possess low cytotoxicity in mammalian cells (CC50 values as high as >300 μM). In addition, the first crystal structures of MtHGPRT (2.03-2.76 Å resolution) have been determined, three of these in complex with novel ANPs and one with GMP and pyrophosphate. These data provide a solid foundation for the further development of ANPs as selective inhibitors of MtHGPRT and as antituberculosis agents.

• MeSH
• antituberkulotika chemie   farmakologie   MeSH
• difosfáty chemie   metabolismus   MeSH
• hypoxanthinfosforibosyltransferasa chemie   metabolismus   MeSH
• inhibitory enzymů chemie   farmakologie   MeSH
• katalytická doména MeSH
• konformace proteinů MeSH
• krystalografie rentgenová MeSH
• kyselina 5'-guanylová chemie   metabolismus   MeSH
• lidé MeSH
• molekulární modely MeSH
• molekulární sekvence - údaje MeSH
• molekulární struktura MeSH
• Mycobacterium tuberculosis účinky léků   enzymologie   MeSH
• nádorové buňky kultivované MeSH
• nádory plic farmakoterapie   patologie   MeSH
• organofosfonáty chemie   metabolismus   MeSH
• prekurzory léčiv chemie   farmakologie   MeSH
• proliferace buněk účinky léků   MeSH
• protinádorové látky chemie   farmakologie   MeSH
• sekvence aminokyselin MeSH
• sekvenční homologie aminokyselin MeSH
• tuberkulóza farmakoterapie   mikrobiologie   MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antituberkulotika MeSH
• difosfáty MeSH
• diphosphoric acid MeSH Prohlížeč
• hypoxanthinfosforibosyltransferasa MeSH
• inhibitory enzymů MeSH
• kyselina 5'-guanylová MeSH
• organofosfonáty MeSH
• prekurzory léčiv MeSH
• protinádorové látky MeSH

1. Nucleotide analogues comprise an important class of drugs used in treatment of viral infections but also cancer. These drugs affect the structural integrity of DNA and activate different pathways and processes in the cell and may directly or indirectly influence the drug metabolizing system. Adefovir dipivoxil (AD) and tenofovir disoproxil (TD) are nucleotide analogues approved for the treatment of chronic hepatitis B and/or HIV/AIDS infection. 2. To evaluate the risk of their drug-drug interactions on the level of drug metabolism, an effect of both compounds on cytochromes P450 expression was studied using cDNA microarrays, real-time RT-PCR and immunoblotting. Mice were given intraperitoneally 25 mg/kg of AD or TD, respectively. As a positive control, a combination of prototypic cytochromes P450 (CYP) inducers, phenobarbital and β-naphthoflavone was chosen. 3. The data obtained showed a significant CYP induction in the positive control group, but no clinically significant induction of CYP genes by AD or TD was observed. Our results support the evidence of safety of AD and TD with respect to drug-drug interactions based on enzyme induction. These findings are important as a plethora of new antivirals of different types are being tested and introduced to clinical practice, mostly to be used in combinations.

• Klíčová slova
• Adefovir, CYP, PMEA, PMPA, antiviral, drug metabolism, induction, tenofovir,
• MeSH
• adenin analogy a deriváty   metabolismus   MeSH
• kvantitativní polymerázová řetězová reakce MeSH
• myši inbrední C57BL MeSH
• organofosfonáty chemie   metabolismus   MeSH
• regulace genové exprese enzymů * MeSH
• sekvenční analýza hybridizací s uspořádaným souborem oligonukleotidů MeSH
• stanovení celkové genové exprese MeSH
• systém (enzymů) cytochromů P-450 genetika   metabolismus   MeSH
• tenofovir MeSH
• western blotting MeSH
• zvířata MeSH
• Check Tag
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• adefovir dipivoxil MeSH Prohlížeč
• adenin MeSH
• organofosfonáty MeSH
• systém (enzymů) cytochromů P-450 MeSH
• tenofovir MeSH

OBJECTIVE AND DESIGN: Tenofovir (TFV) is used in pregnant women as a part of combination antiretroviral treatment to prevent mother-to-child transmission of HIV infection. We aimed to detect whether TFV and/or its prodrug, tenofovir disoproxil fumarate (TDF), are substrates of ATP-binding cassette (ABC) transporters that are functionally expressed in the placenta, namely P-glycoprotein (ABCB1/MDR1), Breast Cancer Resistance Protein (ABCG2/BCRP) and Multidrug Resistance-Associated Protein 2 (ABCC2/MRP2). We employed in-vitro cell-based assays and in-situ animal model to assess possible role of the efflux transporters in transplacental pharmacokinetics of TFV and TDF. METHODS: In-vitro transport assays were performed in MDCKII cells transduced with human ABCB1, ABCG2 or ABCC2. To quantify the effect of these transporters on TFV/TDF transplacental passage, we employed the in-situ model of dually perfused rat term placenta in open and closed setup. RESULTS: In-vitro assays revealed that TDF is a dual substrate of ABCB1 and ABCG2 but not of ABCC2. In contrast, TFV transport was not influenced by any of these transporters. Applying concentration-dependent studies and selective inhibitors, we further confirmed these findings in situ on the organ level; both ABCB1 and ABCG2 limited mother-to-fetus transfer of TDF whereas TFV transplacental passage was not affected by these ABC transporters. CONCLUSION: We propose limited mother-to-fetus transport of both TFV and TDF. While placental transport of TFV is restricted passively, by physical-chemical properties of the molecule, mother-to-fetus passage of TDF is actively hindered by placental ABCB1 and ABCG2 transporters, pumping this compound from trophoblast back to maternal circulation.

• MeSH
• ABC transportér z rodiny G, člen 2 MeSH
• ABC transportéry metabolismus   MeSH
• adenin analogy a deriváty   metabolismus   farmakokinetika   MeSH
• buněčné linie MeSH
• krysa rodu Rattus MeSH
• látky proti HIV metabolismus   farmakokinetika   MeSH
• lidé MeSH
• nádorové proteiny metabolismus   MeSH
• organofosfonáty metabolismus   farmakokinetika   MeSH
• P-glykoprotein metabolismus   MeSH
• P-glykoproteiny MeSH
• potkani Wistar MeSH
• protein spojený s mnohočetnou rezistencí k lékům 2 MeSH
• proteiny spojené s mnohočetnou rezistencí k lékům metabolismus   MeSH
• tenofovir MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• lidé MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• ABC transportér z rodiny G, člen 2 MeSH
• ABC transportéry MeSH
• ABCB1 protein, human MeSH Prohlížeč
• ABCC2 protein, human MeSH Prohlížeč
• ABCG2 protein, human MeSH Prohlížeč
• adenin MeSH
• látky proti HIV MeSH
• nádorové proteiny MeSH
• organofosfonáty MeSH
• P-glykoprotein MeSH
• P-glykoproteiny MeSH
• protein spojený s mnohočetnou rezistencí k lékům 2 MeSH
• proteiny spojené s mnohočetnou rezistencí k lékům MeSH
• tenofovir MeSH

A series of new monophosphates of 1-[2-(phosphonomethoxy)alkyl]thymines, such as PMPTp(,) 3-MeO-PMPTp, HPMPTp, and FPMPTp, were synthesized and tested for their ability to inhibit human thymidine phosphorylase. Kinetic measurements of enzyme activity were performed using thymidine and inorganic phosphate as the substrates. The data show that some monophosphates provide a considerable increase of the multisubstrate inhibitory effect. The highest inhibitory potency was found with (R)-FPMPTp 4c (K (i) (dT) = 4.09 ± 0.47 μM, K (i)(P(i)) = 2.13 ± 0.29 μM) and (R) 3-MeO-PMPTp 4d (K (i) (dT) = 5.78 ± 0.71 μM, K (i)(P(i)) = 2.71 ± 0.37 μM).

• MeSH
• Cricetulus MeSH
• fosfáty MeSH
• fosforylace MeSH
• kinetika MeSH
• křečci praví MeSH
• lidé MeSH
• molekulární struktura MeSH
• organofosfonáty chemická syntéza   chemie   metabolismus   farmakologie   MeSH
• thymidin MeSH
• thymidinfosforylasa antagonisté a inhibitory   MeSH
• thymin analogy a deriváty   chemická syntéza   chemie   metabolismus   farmakologie   MeSH
• zvířata MeSH
• Check Tag
• křečci praví MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• 1-(3-fluoro-2-(phosphonomethoxy)propyl)thymine MeSH Prohlížeč
• fosfáty MeSH
• organofosfonáty MeSH
• thymidin MeSH
• thymidinfosforylasa MeSH
• thymin MeSH

Hexadecyloxypropyl esters of acyclic nucleoside phosphonates containing guanine (G) or hypoxanthine (Hx) and a (S)-[3-hydroxy-2-(phosphonomethoxy)propyl] [(S)-HPMP] or 2-(2-phosphonoethoxy)ethyl (PEE) acyclic moiety have been prepared. The activity of the prodrugs was evaluated in vitro against different virus families. Whereas ester derivatives of PEEHx and (S)-HPMPHx were antivirally inactive, monoesters of PEEG, and mono- and diesters of (S)-HPMPG showed pronounced antiviral activity against vaccinia virus and/or herpesviruses. Monoesters of (S)-HPMPG emerged as the most potent and selective derivatives against these DNA viruses. None of the compounds were inhibitory against RNA viruses and retroviruses.

• MeSH
• antivirové látky chemická syntéza   chemie   metabolismus   farmakologie   MeSH
• buněčné linie MeSH
• DNA viry účinky léků   MeSH
• guanin analogy a deriváty   chemie   MeSH
• hypoxanthin chemie   MeSH
• hypoxanthiny chemie   MeSH
• kyseliny fosforité chemie   MeSH
• lidé MeSH
• nukleosidy chemie   MeSH
• organofosfonáty chemická syntéza   chemie   metabolismus   farmakologie   MeSH
• prekurzory léčiv metabolismus   MeSH
• techniky syntetické chemie MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antivirové látky MeSH
• guanin MeSH
• hypoxanthin MeSH
• hypoxanthiny MeSH
• kyseliny fosforité MeSH
• nukleosidy MeSH
• organofosfonáty MeSH
• prekurzory léčiv MeSH

The antiviral effect of the acyclic nucleoside phosphonate tenofovir (R)-PMPA on double-stranded DNA Cauliflower mosaic virus (CaMV) in Brassica pekinensis plants grown in vitro on liquid medium was evaluated. Double antibody sandwich ELISA and PCR were used for relative quantification of viral protein and detecting nucleic acid in plants. (R)-PMPA at concentrations of 25 and 50 mg/l significantly reduced CaMV titers in plants within 6-9 weeks to levels detectable neither by ELISA nor by PCR. Virus-free plants were obtained after 3-month cultivation of meristem tips on semisolid medium containing 50 mg/l (R)-PMPA and their regeneration to whole plants in the greenhouse. Studying the metabolism of (R)-PMPA in B. pekinensis revealed that mono- and diphosphate, structural analogs of NDP and/or NTP, are the only metabolites formed. The data indicate very low substrate activity of the enzymes toward (R)-PMPA as substrate. The extent of phosphorylation in the plant's leaves represents only 4.5% of applied labeled (R)-PMPA. In roots, we detected no radioactive peaks of phosphorylated metabolites of (R)-PMPAp or (R)-PMPApp.

• MeSH
• adenin analogy a deriváty   metabolismus   farmakologie   MeSH
• antivirové látky metabolismus   farmakologie   MeSH
• biotransformace MeSH
• Brassica metabolismus   virologie   MeSH
• Caulimovirus účinky léků   růst a vývoj   MeSH
• DNA virů analýza   MeSH
• ELISA metody   MeSH
• organofosfonáty metabolismus   farmakologie   MeSH
• polymerázová řetězová reakce metody   MeSH
• tenofovir MeSH
• virová nálož MeSH
• virové proteiny analýza   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• adenin MeSH
• antivirové látky MeSH
• DNA virů MeSH
• organofosfonáty MeSH
• tenofovir MeSH
• virové proteiny MeSH

Solid phase synthesis of phosphonate-modified oligoribonucleotides using 2'-O-benzoyloxymethoxymethyl protected monomers is presented in both 3'→5' and 5'→3' directions. Hybridisation properties and enzymatic stability of oligoribonucleotides modified by regioisomeric 3'- and 5'-phosphonate linkages are evaluated. The introduction of the 5'-phosphonate units resulted in moderate destabilisation of the RNA/RNA duplexes (ΔT(m)-1.8 °C/mod.), whereas the introduction of the 3'-phosphonate units resulted in considerable destabilisation of the duplexes (ΔT(m)-5.7 °C/mod.). Molecular dynamics simulations have been used to explain this behaviour. Both types of phosphonate linkages exhibited remarkable resistance in the presence of ribonuclease A, phosphodiesterase I and phosphodiesterase II.

• MeSH
• exonukleasy metabolismus   MeSH
• fosfodiesterasa I metabolismus   MeSH
• oligoribonukleotidy chemická syntéza   chemie   metabolismus   MeSH
• organofosfonáty chemická syntéza   chemie   metabolismus   MeSH
• pankreatická ribonukleasa metabolismus   MeSH
• simulace molekulární dynamiky MeSH
• techniky syntézy na pevné fázi * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• exonukleasy MeSH
• fosfodiesterasa I MeSH
• oligoribonukleotidy MeSH
• organofosfonáty MeSH
• pankreatická ribonukleasa MeSH
• spleen exonuclease MeSH Prohlížeč