Drug repurposing screen identifies masitinib as a 3CLpro inhibitor that blocks replication of SARS-CoV-2in vitro

Abstract

There is an urgent need for anti-viral agents that treat SARS-CoV-2 infection. The shortest path to clinical use is repurposing of drugs that have an established safety profile in humans. Here, we first screened a library of 1,900 clinically safe drugs for inhibiting replication of OC43, a human beta-coronavirus that causes the common-cold and is a relative of SARS-CoV-2, and identified 108 effective drugs. We further evaluated the top 26 hits and determined their ability to inhibit SARS-CoV-2, as well as other pathogenic RNA viruses. 20 of the 26 drugs significantly inhibited SARS-CoV-2 replication in human lung cells (A549 epithelial cell line), with EC50 values ranging from 0.1 to 8 micromolar. We investigated the mechanism of action for these and found that masitinib, a drug originally developed as a tyrosine-kinase inhibitor for cancer treatment, strongly inhibited the activity of the SARS-CoV-2 main protease 3CLpro. X-ray crystallography revealed that masitinib directly binds to the active site of 3CLpro, thereby blocking its enzymatic activity. Mastinib also inhibited the related viral protease of picornaviruses and blocked picornaviruses replication. Thus, our results show that masitinib has broad anti-viral activity against two distinct beta-coronaviruses and multiple picornaviruses that cause human disease and is a strong candidate for clinical trials to treat SARS-CoV-2 infection.

Characterisation of protease activity during SARS-CoV-2 infection identifies novel viral cleavage sites and cellular targets with therapeutic potential

“…In the case of Bafetinib, a Lyn/Bcr-Abl inhibitor which has off-target activity against SRC the IC 50 was in the nanomolar range ( IC 50 : 0.79 µM, 95% confidence interval 0.23-1.35 µM). Bafetinib has recently been independently identified as an inhibitor of the coronaviruses OC43 and SARS-COV-2 in a large-scale drug-repurposing screen (35). Inhibition with Sorafenib which was included as a positive control and does not directly target any of the protease substrates was in the low micromolar range (Fig.…”

Fixed single-cell RNA sequencing for understanding virus infection and host response

“…research. Drug screening studies showed that many drugs that inhibit replication of OC43 also inhibit SARS-CoV-2 in vitro 17 . First, we infected human lung epithelial A549 cells with coronavirus OC43 at a multiplicity of infection (MOI) of 1 and fixed the cells with PFA, along with a fixed mock infected sample, and performed FD-seq.…”

“…OC43, like SARS-CoV-2, belongs to the family of betacoronaviruses, and is a major human pathogen that causes the common cold. OC43 has been successfully used to discover drugs that inhibit SARS-CoV-2 replication in vitro 17 . We found that human lung cells infected by OC43 were composed of two subpopulations with either low or high viral gene expression.…”

Detecting SARS-CoV-2 3CLpro expression and activity using a polyclonal antiserum and a luciferase-based biosensor

“…We have already begun to share the biosensor and other related reagents with laboratories around the world. Indeed, the biosensor assay was recently used to verify that an antiviral drug that inhibits replication of SARS-CoV-2 targets 3CLpro ( Drayman et al, 2020 ).…”