Interruption of oncornavirus replication by modified rifamycin antibiotics

Area of Science:

• Virology
• Molecular Biology
• Drug Discovery

Background:

• Rifamycin SV derivatives are explored for antiviral properties.
• Oncornaviruses, like murine sarcoma virus (MSV), pose significant health challenges.
• Understanding viral polymerase inhibition is crucial for antiviral development.

Purpose of the Study:

• To evaluate thirteen novel rifamycin SV derivatives for antiviral activity.
• To assess the compounds' effects on viral and cellular polymerases.
• To determine the efficacy of these derivatives in inhibiting oncornavirus-induced cell transformation.

Main Methods:

• Synthesis and testing of thirteen 3'-alkylaminomethyl rifamycin SV derivatives.
• Assays for inhibition of simian sarcoma virus Type 1 DNA polymerase and cellular DNA, RNA, and poly(A) polymerases.
• Cytotoxicity assessment in NIH Swiss mouse 3T3 cells.
• Focus inhibition assays using murine sarcoma virus (MSV).

Main Results:

• None of the thirteen derivatives inhibited viral or cellular polymerase activities.
• Three specific derivatives (N-methyl-N-hydroxyethylaminomethyl, N,N-dimethyl-aminomethyl, and N4-methylpiperazinomethyl rifamycin) demonstrated significant focus inhibition.
• These three compounds exhibited comparable cytotoxicity to existing antivirals like adenine arabinoside and ribavirin but superior focus inhibition.
• Oncornavirus production was inhibited, seemingly by prolonging a growth delay induced by MSV infection.

Conclusions:

• Certain rifamycin SV derivatives can effectively inhibit oncornavirus production.
• The mechanism of inhibition involves exacerbating a delay in viral-induced cell growth, not direct polymerase inhibition.
• These findings suggest potential for developing novel antiviral agents targeting oncornavirus replication.