Identification of tyrphostin AG879 and A9 inhibiting replication of chikungunya virus by screening of a kinase inhibitor library

Chikungunya virus (CHIKV) is a globally public health threat. There are currently no medications available to treat CHIKV infection. High-throughput screening of 419 kinase inhibitors was performed based on the cyto-pathic effect method, and six kinase inhibitors with reduced cytopathic effects, including tyrphostin AG879 (AG879), tyrphostin 9 (A9), sorafenib, sorafenib tosylate, regorafenib, and TAK-632, were identified. The anti- CHIKV activities of two receptor tyrosine kinase inhibitors, AG879 and A9, that have not been previously re-ported, were selected for further evaluation. The results indicated that 50% cytotoxic concentration (CC50) of AG879 and A9 in Vero cells were greater than 30 mu M and 6.50 mu M, respectively and 50% effective concentration (EC50) were 0.84 mu M and 0.36 mu M, respectively. The time-of-addition and time-of-removal assays illustrated that both AG879 and A9 function in the middle stage of CHIKV life cycle. Further, AG879 and A9 do not affect viral attachment; however, they inhibit viral RNA replication, and exhibit antiviral activity against CHIKV Eastern/ Central/South African and Asian strains, Ross River virus and Sindbis virus in vitro.