Mechanism of Action at the Molecular Level of the Antiviral Drug 3(2H)-Isoflavene against Type 2 Poliovirus

Salvati, Anna; Dominicis, A. De; Tait, Sabrina; Canitano, Andrea; Lahm, Armin; Fiore, Lucia

doi:10.1128/aac.48.6.2233-2243.2004

Cited by 39 publications

(33 citation statements)

References 53 publications

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“…These findings were supported by the analysis of drug-resistant viruses, that were shown to carry mutations in VP1. 153 K. Rhodanine 2-thio-4-oxothiazolidine, also known as rhodanine (Fig. 12), is a selective inhibitor of echovirus 12 at a concentration of 12.5 mg/mL, showing no inhibitory effect against other viruses.…”

Section: Jmentioning

confidence: 99%

Selective inhibitors of picornavirus replication

Palma

Vliegen

Clercq

et al. 2008

Medicinal Research Reviews

229

217

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Picornaviruses cover a large family of pathogens that have a major impact on human but also on veterinary health. Although most infections in man subside mildly or asymptomatically, picornaviruses can also be responsible for severe, potentially life-threatening disease. To date, no therapy has been approved for the treatment of picornavirus infections. However, efforts to develop an antiviral that is effective in treating picornavirus-associated diseases are ongoing. In 2007, Schering-Plough, under license of ViroPharma, completed a phase II clinical trial with Pleconaril, a drug that was originally rejected by the FDA after a New Drug Application in 2001. Rupintrivir, a rhinovirus protease inhibitor developed at Pfizer, reached clinical trials but was recently halted from further development. Finally, Biota's HRV drug BTA-798 is scheduled for phase II trials in 2008. Several key steps in the picornaviral replication cycle, involving structural as well as non-structural proteins, have been identified as valuable targets for inhibition. The current review aims to highlight the most important developments during the past decades in the search for antivirals against picornaviruses.

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Section: Jmentioning

confidence: 99%

Selective inhibitors of picornavirus replication

Palma

Vliegen

Clercq

et al. 2008

Medicinal Research Reviews

229

217

View full text Add to dashboard Cite

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“…Other antipolioviral compounds, like 3(2H)-isoflavene and pirodavir, were demonstrated to exert their activity through binding to the capsid and, in the case of pirodavir, stabilizing the native virion (21,22). Some antipicornaviral compounds were found to interfere with a later stage of replication and target nonstructural proteins.…”

Section: Importancementioning

confidence: 99%

Mechanism of Action and Capsid-Stabilizing Properties of VHHs with an In Vitro Antipolioviral Activity

Schotte

Strauß

Thys

et al. 2014

J Virol

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Previously, we reported on the in vitro antiviral activity of single-domain antibody fragments (VHHs) directed against poliovirus type 1. Five VHHs were found to neutralize poliovirus type 1 in an in vitro setting and showed 50% effective concentrations (EC 50 s) in the nanomolar range. In the present study, we further investigated the mechanism of action of these VHHs. All five VHHs interfere at multiple levels of the viral replication cycle, as they interfere both with attachment of the virus to cells and with viral uncoating. The latter effect is consistent with their ability to stabilize the poliovirus capsid, as observed in a ThermoFluor thermal shift assay, in which the virus is gradually heated and the temperature causing 50% of the RNA to be released from the capsid is determined, either in the presence or in the absence of the VHHs. The VHH-capsid interactions were also seen to induce aggregation of the virus-VHH complexes. However, this observation cannot yet be linked to their mechanism of action. Cryo-electron microscopy (cryo-EM) reconstructions of two VHHs in complex with poliovirus type 1 show no conformational changes of the capsid to explain this aggregation. On the other hand, these reconstructions do show that the binding sites of VHHs PVSP6A and PVSP29F overlap the binding site for the poliovirus receptor (CD155/PVR) and span interfaces that are altered during receptor-induced conformational changes associated with cell entry. This may explain the interference at the level of cell attachment of the virus as well as their effect on uncoating. IMPORTANCEThe study describes the mechanism of neutralization and the capsid-stabilizing activity of five single-domain antibody fragments (VHHs) that have an in vitro neutralizing activity against poliovirus type 1. The results show that the VHHs interfere at multiple levels of the viral replication cycle (cell attachment and viral uncoating). These mechanisms are possibly shared by some conventional antibodies and may therefore provide some insight into the natural immune responses. Since the binding sites of two VHHs studied by cryo-EM are very similar to that of the receptor, the VHHs can be used as probes to study the authentic virus-cell interaction. The structures and conclusions in this study are original and raise interesting findings regarding virus-receptor interactions and the order of key events early in infection.

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“…The acquisition of compensatory mutations occasionally restores replication capacity (7), and coselection for dependence on the antiviral chemical compounds has been documented (1,19). However, to the best of our knowledge this represents the first documentation of a virus's evolving a mechanism to productively utilize an antiviral agent to stimulate its fitness at a level substantially higher than the uninhibited wild-type level.…”

Section: Discussionmentioning

confidence: 99%

“…While viruses often acquire resistance to antiviral agents, resistance mutants generally exhibit lower fitness than the wildtype strain in the absence of the inhibitor (6,16,17,25) and can develop a dependency on the antiviral agent (1,19). However, the molecular mechanism of dependency rarely, if ever, involves the productive use of the antiviral agent to elevate fitness above the uninhibited wild-type level.…”

mentioning

confidence: 99%

Viral Adaptation to an Antiviral Protein Enhances the Fitness Level to Above That of the Uninhibited Wild Type

Cherwa

Sanchez-Soria

Wichman

et al. 2009

J Virol

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Viruses often evolve resistance to antiviral agents. While resistant strains are able to replicate in the presence of the agent, they generally exhibit lower fitness than the wild-type strain in the absence of the inhibitor. In some cases, resistant strains become dependent on the antiviral agent. However, the agent rarely, if ever, elevates dependent strain fitness above the uninhibited wild-type level. This would require an adaptive mechanism to convert the antiviral agent into a beneficial growth factor. Using an inhibitory scaffolding protein that specifically blocks X174 capsid assembly, we demonstrate that such mechanisms are possible. To obtain the quintuple-mutant resistant strain, the wild-type virus was propagated for approximately 150 viral life cycles in the presence of increasing concentrations of the inhibitory protein. The expression of the inhibitory protein elevated the strain's fitness significantly above the uninhibited wild-type level. Thus, selecting for resistance coselected for dependency, which was characterized and found to operate on the level of capsid nucleation. To the best of our knowledge, this is the first report of a virus evolving a mechanism to productively utilize an antiviral agent to stimulate its fitness above the uninhibited wild-type level. The results of this study may be predictive of the types of resistant phenotypes that could be selected by antiviral agents that specifically target capsid assembly.While viruses often acquire resistance to antiviral agents, resistance mutants generally exhibit lower fitness than the wildtype strain in the absence of the inhibitor (6,16,17,25) and can develop a dependency on the antiviral agent (1, 19). However, the molecular mechanism of dependency rarely, if ever, involves the productive use of the antiviral agent to elevate fitness above the uninhibited wild-type level. Many studies are conducted with animal viruses, often in clinical settings, which can impose restraints on the experimental durations. Thus, prolonged exposure to antiviral agents may be required for the emergence of a multiply mutant strain that has evolved mechanisms to productively utilize inhibitors.Due to its rapid replication, bacteriophage X174 has become an attractive model system for evolutionary studies (2,3,23,24). Selective pressures can be applied for hundreds of infection cycles in a relatively short period of time. Using the atomic structure of assembly intermediates as a guide (8, 9, 15), viral scaffolding proteins that inhibit virion assembly have been designed (4). The molecular mechanism of inhibition was characterized, and resistance mutants were isolated via onestep genetic selections (4). In this study we report the isolation of a more robust resistant mutant. The quintuple mutant was generated by propagating X174 for approximately 150 life cycles in the presence of increasing concentrations of the inhibitory protein, which was derived from the external scaffolding D protein. This protein forms asymmetric dimers that direct procapsid assembly. A...

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Mechanism of Action at the Molecular Level of the Antiviral Drug 3(2H)-Isoflavene against Type 2 Poliovirus

Cited by 39 publications

References 53 publications

Selective inhibitors of picornavirus replication

Selective inhibitors of picornavirus replication

Mechanism of Action and Capsid-Stabilizing Properties of VHHs with an In Vitro Antipolioviral Activity

Viral Adaptation to an Antiviral Protein Enhances the Fitness Level to Above That of the Uninhibited Wild Type

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