Résumé
ABSTRACT Antiviral drug resistance is the most important factor contributing to treatment failure using nucleos(t)ide analogs such as lamivudine for chronic infection with hepatitis B virus (HBV). Development of a system supporting efficient replication of clinically resistant HBV strains is imperative, and new antiviral drugs are needed urgently to prevent selection of drug-resistant HBV mutants. A novel fluorinated cytidine analog, NCC (N-cyclopropyl-4′-azido-2′-deoxy-2′-fluoro-β-d-cytidine), was recently shown to strongly inhibit human HBV in vitro and in vivo. This study was designed to evaluate the antiviral activity of NCC against lamivudine-resistant HBV. We generated a stable cell line encoding the major pattern of lamivudine-resistant mutations rtL180M/M204V and designated it "HepG2.RL1". Immuno-transmission electron microscopic examination and enzyme-linked immunosorbent assay were used to detect secretion of HBV-specific particles and antigens. Quantification of extracellular DNA and intracellular DNA of HepG2.RL1 cells by quantitative real-time polymerase chain reaction revealed >625-fold and >5556-fold increases in the 50% inhibitory concentration of lamivudine, respectively, compared with that for the wild-type virus. The results showed that NCC inhibited DNA replication and HBeAg production in wild-type or lamivudine-resistant HBV in a dose-dependent manner. In conclusion, screening for antiviral compounds active against lamivudine-resistant HBV can be carried out with relative ease using hepG2.RL1 cells. NCC is a potential antiviral agent against wild-type HBV and clinical lamivudine-resistant HBV and deserves evaluation for the treatment of HBV infection.
Sujets)
Humains , Femelle , Adulte d'âge moyen , Antiviraux/pharmacologie , Réplication virale/effets des médicaments et des substances chimiques , Virus de l'hépatite B/effets des médicaments et des substances chimiques , Lamivudine/pharmacologie , Cytidine/analogues et dérivés , ADN viral/composition chimique , Tests de sensibilité microbienne , Lignée cellulaire , Virus de l'hépatite B/isolement et purification , Virus de l'hépatite B/physiologie , Hépatocytes/virologie , Résistance virale aux médicaments/effets des médicaments et des substances chimiques , MutationRésumé
Some modified nucleosides were prepared from 5,6-disubstituted uridine, 5-substituted cytidine and cytidine. Different nucleophilic substitution reactions were carried out in alkaline or neutral medium. Some of these reactions describe ring formation
Sujets)
Uridine/analogues et dérivés , Uridine/composition chimique , Cytidine/composition chimique , Cytidine/analogues et dérivésRésumé
Synthesis of some cytidine derivatives involving 4,5 cyclisation are performed by the individual reactions of both of 5-hydroxy, 5-mercapto and 5-amino cytidines with chloroethyl formate, thionyl chloride and thiophosgene successively. On the other hand, reactions of cytidine with chloroacetone or chloropropionaldehyde give 3,4-cyclized cytidine products