Project description:Focused on the cytochromes P450 (CYPs), we studied gene expression changes in mice treated with acyclic nucleoside antivirals adefovir and tenofovir. Positive control group was treated by prototypic CYP inducers phenobarbital and beta-naphthoflavone. Expression profiling with Steroltalk cDNA arrays revealed major changes in CYP mRNA expression in the inducers-treated group but only minor changes in CYP expression in the adefovir and tenofovir groups.
Project description:Focused on the cytochromes P450 (CYPs), we studied gene expression changes in mice treated with acyclic nucleoside antivirals adefovir and tenofovir. Positive control group was treated by prototypic CYP inducers phenobarbital and beta-naphthoflavone. Expression profiling with Steroltalk cDNA arrays revealed major changes in CYP mRNA expression in the inducers-treated group but only minor changes in CYP expression in the adefovir and tenofovir groups. 3 groups representing treatments with adefovir, tenofovir and phenobarbital + beta-naphthoflavone. 4-5 animals in each group + a dye swap. Pooled samples from 10 animals treated with saline was used as a reference. Daily application of antivirals for three days, samples were collected after 24 hours from the last treatment.
Project description:With respect to the strong antiviral activity of (S)-1-[3-hydroxy-2-(phosphonomethoxy)propyl]-5-azacytosine various types of its side chain fluorinated analogues were prepared. The title compound, (S)-1-[3-fluoro-2-(phosphonomethoxy)propyl]-5-azacytosine (FPMP-5-azaC) was synthesised by the condensation reaction of (S)-2-[(diisopropoxyphosphoryl)methoxy)-3-fluoropropyl p-toluenesulfonate with a sodium salt of 5-azacytosine followed by separation of appropriate N 1 and O 2 regioisomers and ester hydrolysis. Transformations of FPMP-5-azaC to its 5,6-dihydro-5-azacytosine counterpart, amino acid phosphoramidate prodrugs and systems with an annelated five-membered imidazole ring, i.e. imidazo [1,2-a][1,3,5]triazine derivatives were also carried out. 1-(2-Phosphonomethoxy-3,3,3-trifluoropropyl)-5-azacytosine was prepared from 5-azacytosine and trifluoromethyloxirane to form 1-(3,3,3-trifluoro-2-hydroxypropyl)-5-azacytosine which was treated with diisopropyl bromomethanephosphonate followed by deprotection of esters. Antiviral activity of all newly prepared compounds was studied. FPMP-5-azaC diisopropyl ester inhibited the replication of herpes viruses with EC50 values that were about three times higher than that of the reference anti-HCMV drug ganciclovir without displaying cytotoxicity.
Project description: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).
Project description:A convenient and efficient synthesis of a novel class of acyclic nucleoside phosphonates derived from 2-(phosphonomethoxy)propanoic acid has been developed. The key step of the synthesis is the optimized oxidation of the 3-hydroxy-2-(phosphonomethoxy)propyl (HPMP) analogues to the corresponding 2'-carboxy-PME (CPME) derivatives using the TEMPO/NaClO2/NaClO oxidizing system. Although (S)-3-(adenin-9-yl)-2-(phosphonomethoxy)propanoic acid ((S)-CPMEA) has been designed as a compound with potential anti-HIV activity, none of the newly prepared CPME analogues exhibited any antiviral activity.
Project description:Bordetella pertussis adenylate cyclase toxin (ACT) and Bacillus anthracis edema factor (EF) are key virulence factors with adenylate cyclase (AC) activity that substantially contribute to the pathogenesis of whooping cough and anthrax, respectively. There is an urgent need to develop potent and selective inhibitors of bacterial ACs with prospects for the development of potential antibacterial therapeutics and to study their molecular interactions with the target enzymes. Novel fluorescent 5-chloroanthraniloyl-substituted acyclic nucleoside phosphonates (Cl-ANT-ANPs) were designed and synthesized in the form of their diphosphates (Cl-ANT-ANPpp) as competitive ACT and EF inhibitors with sub-micromolar potency (IC50 values: 11-622 nm). Fluorescence experiments indicated that Cl-ANT-ANPpp analogues bind to the ACT active site, and docking studies suggested that the Cl-ANT group interacts with Phe306 and Leu60. Interestingly, the increase in direct fluorescence with Cl-ANT-ANPpp having an ester linker was strictly calmodulin (CaM)-dependent, whereas Cl-ANT-ANPpp analogues with an amide linker, upon binding to ACT, increased the fluorescence even in the absence of CaM. Such a dependence of binding on structural modification could be exploited in the future design of potent inhibitors of bacterial ACs. Furthermore, one Cl-ANT-ANP in the form of a bisamidate prodrug was able to inhibit B. pertussis ACT activity in macrophage cells with IC50 =12 μm.
Project description:A series of novel acyclic nucleoside phosphonates (ANPs) was synthesized as potential adenylate cyclase inhibitors, where the adenine nucleobase of adefovir (PMEA) was replaced with a 5-substituted 2-aminothiazole moiety. The design was based on the structure of MB05032, a potent and selective inhibitor of fructose 1,6-bisphosphatase and a good mimic of adenosine monophosphate (AMP). From the series of eighteen novel ANPs, which were prepared as phosphoroamidate prodrugs, fourteen compounds were potent (single digit micromolar or submicromolar) inhibitors of Bordetella pertussis adenylate cyclase toxin (ACT), mostly without observed cytotoxicity in J774A.1 macrophage cells. Selected phosphono diphosphates (nucleoside triphosphate analogues) were potent inhibitors of ACT (IC50 as low as 37 nM) and B. anthracis edema factor (IC50 as low as 235 nM) in enzymatic assays. Furthermore, several ANPs were found to be selective mammalian AC1 inhibitors in HEK293 cell-based assays (although with some associated cytotoxicity) and one compound exhibited selective inhibition of mammalian AC2 (only 12% of remaining adenylate cyclase activity) but no observed cytotoxicity. The mammalian AC1 inhibitors may represent potential leads in development of agents for treatment of human inflammatory and neuropathic pain.
Project description:A series of the novel C-5 alkynyl pyrimidine nucleoside analogues (1-14) in which the sugar moiety was replaced by the conformationally restricted Z- and E-2-butenyl spacer between the phthalimido and pyrimidine ring were synthesized by using Sonogashira cross-coupling reaction. Cytostatic activity evaluation of the novel compounds showed that E-isomers exhibited, in general, better cytostatic activities than the corresponding Z-isomers. E-isomer 14 exhibited the best cytostatic effect against all evaluated malignant cell lines, particularly against hepatocellular carcinoma (Hep G2, IC(50)=4.3microM). However, this compound was also cytotoxic to human normal fibroblasts (WI 38). Its Z-isomer 7 showed highly specific antiproliferative activity against Hep G2 (IC(50)=18microM) and no cytotoxicity to WI 38. Moreover, compounds 3, 4 and 14 expressed some marginal inhibitory activity against HIV-1 and HIV-2.
Project description:Although the acyclic nucleoside phosphonates cidofovir, adefovir and tenofovir are approved for treating human cytomegalovirus, hepatitis B and HIV infections, respectively, their utility is limited by low oral bioavailability, renal toxicity and poor cell penetration. Research over the past decade has shown that these undesirable features can be eliminated by esterifying the compounds with an alkoxyalkyl group, in effect disguising them as lysophospholipids. In this modified form, the drugs are readily taken up in the gastrointestinal tract and have a prolonged circulation time in plasma. The active metabolite also has a long half life within cells, permitting infrequent dosing. Because these modified drugs are not recognized by the transport mechanisms that cause the accumulation of acyclic nucleoside phosphonates in renal tubular cells, they lack nephrotoxicity. Alkoxyalkyl esterification also markedly increases the in vitro antiviral activity of acyclic nucleoside phosphonates by improving their delivery into cells. For example, an alkoxyalkyl ester of cyclic-cidofovir, a less soluble compound, retains anti-CMV activity for 3 months following a single intravitreal injection. Two of these novel compounds, hexadecyloxypropyl-cidofovir (CMX001) and hexadecyloxypropyl-tenofovir (CMX157) are now in clinical development. This article focuses on the hexadecyloxypropyl and octadecyloxyethyl esters of cidofovir and (S)-HPMPA, describing their synthesis and the evaluation of their in vitro and in vivo activity against a range of orthopoxviruses, herpesviruses, adenoviruses and other double-stranded DNA viruses. The extension to other nucleoside phosphonate antivirals is highlighted, demonstrating that this novel approach can markedly improve the medicinal properties of these drugs.
Project description:A new class of acyclic nucleoside phosphonates, the 5-phosphono-pent-2-en-1-yl nucleosides and their hexadecyloxypropyl esters, were synthesized from butyn-1-ol. Only the hexadecyloxypropyl esters showed antiviral activity against herpes simplex virus type 1, in vitro. Hexadecyloxypropyl 1-(5-phosphono-pent-2-en-1-yl)-thymine was the most active and selective compound among the synthesized nucleotides with an EC50 value of 0.90 microM.