Identification of a compound series by high throughput screening capable of reversing the antiviral effect of Ribavirin in tissue culture

摘要

A compound series capable of reversing the antiviral effect of Ribavirin (RBV) against H1N1 wasudidentified from a high throughput screen designed to discover compounds capable of increasing theudfidelity of the RNA-dependent RNA polymerase (RDRP) n ribovirus quasispecies. Two lead compounds,udRIC-1 (EC50 of 78.4 nM) and RIC-2 (EC50 of 217 nM), returned viral growth to control levels byudcompletely inhibiting the antiviral activity of RBV. Both compounds demonstrated a loss of activityudwhen incubated at 37°C in media only, losing functionality within 3 hours. Incubation of RIC-1 or RIC-2udwith cells for only 2.5 minutes, however, was able to maintain viral growth by inhibiting RBV for theudfull 72 hour growth period. Subsequent testing showed the RIC series was not effective against a secondudmutagen, 5-fluorouracil, and RIC-2 did not prevent or slow the development of antiviral resistance whenudviral populations were grown in the presence of Zanamivir. Furthermore, RIC-1 was ineffective inudalleviating inhibition of the inosine 5’-monophosphate dehydrogenase (IMPDH) pathway by theudinhibitor mycophenolic acid (MPA). Anti-RBV activity was relieved by increasing the concentration ofudRBV, suggesting the RIC series acts to competitively inhibit RBV. The mechanism of action associatedudwith the RIC compound series is still unclear; however, it appears to act independent of the intendedudfunction of RDRP fidelity modification.