Cell metabolism of acyclovir phosphonate derivatives and antiherpesvirus activity of their combinations with alpha2-interferon

MODERN ETHIOTROPIC CHEMOTHERAPY OF HERPESVIRUS INFECTIONS: ADVANCES, NEW TRENDS AND PERSPECTIVES. ALPHAHERPESVIRINAE (part I)

Modern therapy of infections caused by alpha-herpesviruses is based on drugs belonging to the class of modified nucleosides (acyclovir) and their metabolic progenitors - valine ester of acyclovir and famciclovir (prodrug of penciclovir). The biological activity of these compounds is determined by the similarity of their structure to natural nucleosides: modified nucleosides compete with natural nucleosides for binding to DNA-polymerase and, due to their structural features, inhibit its activity. However, the emergence of variants of viruses resistant to the antiviral drugs available in the arsenal of modern medicine necessitates the search for new compounds able of effectively inhibiting the reproduction of viruses. These compounds should be harmless to the macroorganisms, convenient to use, and overcoming the drug resistance barrier in viruses. The search for literature in international databases (PubMed, MedLine, RINC, etc.) in order to obtain information on promising developments that open new possibilities for treating herpesvirus infection and subsequent analysis of the collected data made it possible to determine not only the main trends in the search for new antiviral agents, but also to provide information on the compounds most promising for the development of anti-herpesvirus drugs.

Phosphoramidate derivatives of acyclovir: synthesis and antiviral activity in HIV-1 and HSV-1 models in vitro

The antiviral activity against HIV and HSV and the chemical stability of ACV phosphoramidate derivatives were studied. The phosphoramidates of ACV demonstrated moderate activity. The best compound appeared to be 9-(2-hydroxymethyl)guanine phosphoromonomorpholidate (7), which inhibited virus replication in pseudo-HIV-1 particles by 50% at 50 μM. It also inhibited replication of wild-type HSV-1 (9.7 μM) as well as an acyclovir-resistant strain (25 μM). None of the synthesised compounds showed any cytotoxicity.

[Enzymatic activity of thymidine kinase of herpes simlex virus strain resistant to H-phosphonates of Acv]

Cloned laboratory mutants of herpes simplex virus type I resistant to acycloguanosine H-phosphonate have been investigated. For all clones were shown that mutations resulted to increasing of sensitivity to acting of sidofovir. Thymidine kinase of mutant viruses partially preserves the ability to phosphorilate thymidine, but loses the ability to phosphorilate BVDU.

[Cloning, expression, isolation and properties of thymidine kinase herpes simplex virus, strain L2]

A thymidine kinase UL23 gene (EC 2.7.1.145) from an acyclovir-sensitive strain L2 of herpes simplex virus type 1 was cloned and expressed in E. coli. Enzyme was purified by chromatography to a homogeneous state controlled by PAG electrophoresis. The Michaelis constants for the reactions with thymidine and an acyclovir were determined. It was found that enzyme phosphorilate some modified nucleosides such as d2T, d4T, d2C, 3TC, FLT, BVDU, GCV. A comparison of the purified enzyme properties and properties ofthymidine kinase of other strains of herpes simplex virus, previously published was carried out. It is shown that enzyme is inhibited by acyclovir H-phosphonate.

[Liver cirrhosis patogenetics: polymorphism of glutation S-transferase genes]

Association of deletion polymorphism in GSTT1 and GSTM1 genes and polymorphic variant A313G of GSTP1 gene with cirrhosis diseases and 4-year survival rate for the Tomsk region (West Siberia) patients were tested. Homozygous deletion of GSTM1 gene (null genotype) was a protective factor for alcoholic and mixed (HCV, HBV and alcohol) liver cirrhosis development. The patients from the joint group (all etiology forms) as well as having alcoholic and mixed cirrhosis had lower frequency of GSTM1 null genotype (39.2, 39.0, and 34.2%, respectively) in comparison with the control group (64.6%). The GSTM1 null genotype and GSTP1 gene A313G polymorphic variant correlated with the patients' survival rate. The patients survived in comparison with the dead had higher frequency of a GSTM1 null genotype (46.6 vs. 30.2%) and GSTP1 AA genotype (63.1 vs. 40.5%), and lower frequency of GSTP1 AG (A313G) genotype (31.1 vs. 51.2%). A survival rate was 2.5 times higher for patients having GSTP1 AA genotype in comparison with the GG and AG genotype carriers and 2 times higher for patients having GSTM1 null genotype than the gene carriers. A 4-year fatal case probability was 2.3 times higher among the patients having heterozygous AG GSTP1 genotype in comparison with homozygous AA and GG genotype carriers.