Alkoxylalkyl Esters of Nucleotide Analogs Inhibit Polyomavirus DNA Replication and Large T Antigen Activities

Area of Science:

• Virology
• Drug Discovery
• Molecular Biology

Background:

• Polyomavirus infections are typically benign but can be fatal in immunocompromised individuals.
• Currently, no approved drugs specifically treat polyomavirus infections.
• Cidofovir, an antiviral drug, is repurposed for polyomavirus treatment, but its mechanisms are not fully understood.

Purpose of the Study:

• To identify the viral targets of cidofovir derivatives in polyomavirus infections.
• To investigate the mechanism by which cidofovir derivatives inhibit polyomavirus DNA replication.
• To evaluate the efficacy of alkoxyalkyl ester derivatives of cidofovir as direct antiviral agents.

Main Methods:

• Utilized cell-free human extracts and an in vitro viral replication system with purified proteins.
• Assessed the impact of alkoxyalkyl ester derivatives of cidofovir on polyomavirus DNA replication.
• Measured the DNA helicase and DNA binding activities of polyomavirus large tumor antigen (Tag) in the presence of the drug derivatives.

Main Results:

• Alkoxyalkyl ester derivatives of cidofovir demonstrated efficient inhibition of polyomavirus DNA replication in vitro.
• Low concentrations of these derivatives significantly reduced the DNA helicase and DNA binding activities of polyomavirus Tags.
• Inhibition of Tag DNA binding (ssDNA and dsDNA) appears to be a key mechanism for blocking viral replication.

Conclusions:

• Polyomavirus large tumor antigen (Tag) activities are identified as a direct viral target for cidofovir derivatives.
• Alkoxyalkyl ester derivatives of cidofovir are effective antiviral agents in vitro without requiring intracellular conversion.
• The study suggests that the antiviral mechanisms of nucleotide analog-based drugs are more complex than previously assumed.