[Influence of membrane-active polyanions on various stages of the human cytomegalovirus life cycle in vitro].

Human cytomegalovirus (CMV), an agent of infection (CMVI), lethally dangerous for immune deficient neonates and adults was investigated in vitro as a target for a therapeutic effect of new membrane-active polyanionic compounds (MPC). Previous studies on the alicycle- and sulfate-modified carboxy-MPCs revealed a well-defined tendency of the anti-CMV activity amplification in parallel with increasing of the content of sulfate groups, enhancing the negative charge of the macromolecule. The dominating role of the electrostatic factor was confirmed by the highest activity of AS-688, compound with maximum sulfation among the tested MPCs. Its selectivity index (SI) of the CMVI inhibition in human diploid fibroblast cells reached 5450, 7500, 250 and 4286 in the microbicidal, viricidal, prophylactic and therapeutic schemes of the experiment respectively. The antiviral activity at the first, second and third schemes was explained by the polyanion-typical potential of electrostatic neutralization of the countercharged virions and prevention of the virus adsorption on the cell membranes (in competition with heparin sulfate, a cellular receptor of CMV), whereas the therapeutic effect required the ability of MPC to influence the intracellular stages of the CMV life cycle. The PCR and immunochemical assays revealed an inhibitory action of AS-688 on replication of the viral DNA and the following synthesis of the late viral protein gB with efficiency similar to that of gancyclovir (GCV). However, in contrast to GCV, acting as inhibitor of enzyme (viral RNA-polymerase) factor of the biosynthesis, the therapeutic activity of MPC could be interpreted by competition with viral RNA/DNA due to the specific character of the MPC molecular basis, initially constructed on the principle of nucleic acids backbone and charge adjustable imitation. This mechanism assuming reduction of the cytotoxicity risks, explained the experimentally observed fact of low cytotoxicity of MPCs and possible achievement of high SI. The MPC ability to penetrate into the cells without disruption of cellular membrane permeability was confirmed in experiments with the fluorescent-labeled derivate AS-679, structurally and functionally related to AS-688. In the light of the previously described HIV inhibiting properties of AS-688, AS-679 and MPC analogous, the results could be considered prospective in development of new highly effective agents for combined antiviral protection.

[Antiviral activity of polycarboxylic substances modified by cage hydrocarbon and sulfoacid pharmacophors against cytomegalovirus infection in vitro].

Human cytomegalovirus (CMV) infection (CMVI) results in lethal risks at the immunodeficiency status, including the HIV co-infection. Carboxy-mimickers of the polymeric backbone of nucleic acids, potential agonists and antagonists of the virus genome were developed as promising candidates for the antiviral protective agents. In parallel with stimulation of antiviral immunity the mimickers derived membrane potent compounds (MPC), were shown to be able to prevent directly and efficiently the cell infection by various strains of the human immunodeficiency virus (HIV) [Antibiotics and Chemother 2003; 48: 2:29-41; 5:7-15]. The paper presents new data and discussion of the results on investigation of the MPC, modified by the previously designed adamantane or norbornene and by the recently applied sulfoacidic pharmacophores in the experimental model of CMVI in vitro (human diploid fibroblast cells). Eight substances with various ratios of theabove mentioned cage-hydrocarbon and/or anion pharmacophores in the macromolecule were tested and active MPC modifications were detected which efficiently inhibited the CMVI with high indexes of selectivity up to 250, 4286 and 7500 in prophylactic, therapeutic and viricidal experimental schemes respectively. Modulating influence of the lipotropic (cage-hydrocarbon) pharmacophores on the anti-CMV activity was observed only in the viricidal and prophylactic experimental schemes, in which the lipid membranes of the cells and/or virus envelopes were involved. Still, the dominant role in the antiviral activity of MPC in all the experimental schemes was played by the sulfoacid-anionic chemical structure modulation. By increasing the density of the negative charge of the macromolecules to the levels comparable with the charge of the genome molecules, theanionic modification evidently amplified the potential of the antagonistic competition of the synthetic MPC with the virus genome, thus impairing the virus-specific interactions. The most promising compounds AS-688 and AS-678/-679 were selected for further investigation of the mechanisms of the anti-CMV and anti-HIV activity.

[Carboxy mimetic derivatives of nucleic acid polymeric backbones inhibiting human cytomegalovirus. 1. In vitro microbicidal effect].

The artificial polycarboxyacidic compounds (PC), imitating the principle of furan-derived and negatively charged structures alternating in the polymeric backbone of nucleic acids, previously explored as interferon inductors and stimulators of antiviral immunity in vivo, were modified by the side groups to amplify the direct antiviral potency in vitro and investigated in the cell culture model of human diploid fibroblasts infected with human cytomegalovirus (CMV) in a microbicidal scheme. Reconstruction from the PC to membrane potent compounds (MPC) was carried out by covalent modification with lipotropic pharmacophores (of cage-hydrocarbon structures similar to rimantadine or camphor-like terpenoids), as well as by conversion of the carboxy groups to sulfate-anionic derivates, related to the CMV sensitive heparansulfate receptor (HSR) of the cells. Both the factors of the MPC structure-functional modulation (lipotropic and anionic) were found to be effective tools for amplification of the microbicidal activity. The maximum inhibitory effect against CMV and minimum cytotoxicity (with the best selectivity, the chemotherapeutic index of > or = 3000-5000) were achieved mainly through increasing the anionic groups content, elevating the MPC negative charge to the level comparable with one of the like charged viral genome and HSR. In relation with the previously found anti-HIV efficacy of the same MPCs in analogous experimental models and in view of the fact that CMV is one of the most dangerous opportunistic co-factors of HIV/AIDS pathogenesis, the obtained data can be used as a basis for further development of new generation microbicides, promising for combined prevention of sexually transmitted infections.