Rapid repurposing of existing drugs as new therapeutics for COVID-19 has been an important strategy in the management of disease severity during the ongoing SARS-CoV-2 pandemic. Here, we used high-throughput docking to screen 6000 compounds within the DrugBank library for their potential to bind and inhibit the SARS-CoV-2 3 CL main protease, a chymotrypsin-like enzyme that is essential for viral replication. For 19 candidate hits, parallel in vitro fluorescence-based protease-inhibition assays and Vero-CCL81 cell-based SARS-CoV-2 replication-inhibition assays were performed. One hit, diclazuril (an investigational anti-protozoal compound), was validated as a SARS-CoV-2 3 CL main protease inhibitor in vitro (IC 50 value of 29 µM) and modestly inhibited SARS-CoV-2 replication in Vero-CCL81 cells. Another hit, lenvatinib (approved for use in humans as an anti-cancer treatment), could not be validated as a SARS-CoV-2 3 CL main protease inhibitor in vitro , but serendipitously exhibited a striking functional synergy with the approved nucleoside analogue remdesivir to inhibit SARS-CoV-2 replication, albeit this was specific to Vero-CCL81 cells. Lenvatinib is a broadly-acting host receptor tyrosine kinase (RTK) inhibitor, but the synergistic effect with remdesivir was not observed with other approved RTK inhibitors (such as pazopanib or sunitinib), suggesting that the mechanism-of-action is independent of host RTKs. Furthermore, time-of-addition studies revealed that lenvatinib/remdesivir synergy probably targets SARS-CoV-2 replication subsequent to host-cell entry. Our work shows that combining computational and cellular screening is a means to identify existing drugs with repurposing potential as antiviral compounds. Future studies could be aimed at understanding and optimizing the lenvatinib/remdesivir synergistic mechanism as a therapeutic option.
【저자키워드】 SARS-CoV-2, antiviral drug, drug synergy, 【초록키워드】 COVID-19, SARS-CoV-2 pandemic, disease severity, Human, Antiviral compounds, Remdesivir, drug, docking, protease, in vitro, Replication, Protease inhibitor, Viral, viral replication, management, Rapid, target, DrugBank, inhibitor, anti-cancer treatment, synergy, SARS-CoV-2 replication, mechanism, cellular, therapeutic option, independent of, tyrosine, Pazopanib, synergistic effect, lenvatinib, enzyme, host receptor, Compound, Vero-CCL81 cells, nucleoside, Inhibition assays, diclazuril, sunitinib, Host, Future, synergistic, independent, identify, performed, subsequent, inhibit, inhibited, approved, exhibited, functional, inhibit SARS-CoV-2, the SARS-CoV-2, Vero-CCL81, 【제목키워드】 cellular, synergistic, Combined, identify,