Repurposing Screens of FDA-Approved Drugs Identify 29 Inhibitors of SARS-CoV-2

Abstract

Materials and Methods Viruses and Cells SARS-CoV-2 (BetaCoV/Korea/KCDC03/2020) was provided by the Korea Centers for Disease Control and Prevention (NCCP43326). Vero cells (CCL-81) were purchased from the American Type Culture Collection (ATCC) and maintained in Dulbecco's modified Eagle medium (DMEM) supplemented with 10% fetal bovine serum (both HyClone, USA). SARS-CoV-2 was expanded in the Vero cells and titers were determined by plaque assay. All experiments were performed in a Biosafety Level 3 (BSL3) facility. Chemical Library and Antibodies The FDA-approved drug library of 1,473 drugs and remdesivir were provided by the Korea Chemical Bank at the Korea Research Institute of Chemical Technology (KRICT). The J2 anti-double-stranded RNA (dsRNA) antibody was purchased from English and Scientific Consulting Kft. (Szirák, Hungary, catalog no.10010200). Alexa Fluor 488-conjugated goat anti-mouse antibody was obtained from Life Technologies (USA, catalog no. A11001). Antiviral Screen One day before infection, Vero cells were seeded in 96-well plates at a density of 1 × 10 4 cells per well. Each compound was added at 20 μM final concentration. Cells were then infected with SARS-CoV-2 at an MOI of 0.5. Three days after infection, the cytopathic effects (CPE) of the virus were determined by microscopic examination. COVID-19, caused by the novel coronavirus SARS-CoV-2, has spread globally and caused serious social and economic problems. The WHO has declared this outbreak a pandemic. Currently, there are no approved vaccines or antiviral drugs that prevent SARS-CoV-2 infection. Drugs already approved for clinical use would be ideal candidates for rapid development as COVID-19 treatments. In this work, we screened 1,473 FDA-approved drugs to identify inhibitors of SARS-CoV-2 infection using cell-based assays. The antiviral activity of each compound was measured based on the immunofluorescent staining of infected cells using anti-dsRNA antibody. Twenty-nine drugs among those tested showed antiviral activity against SARS-CoV-2. We report this new list of inhibitors to quickly provide basic information for consideration in developing potential therapies.

The Petasites hybridus CO2-extract (Ze 339) blocks SARS-CoV-2 replication in vitro

“…Similar IC 50 values ranging between 1-11 µM for remdesivir have been reported in the literature [51,52,54]. Compared to remdesivir, isopetasin and neopetasin also exerted potent antiviral activities with IC 50 values ranging from 0.79 µM -1.2 µM (Figure 3).…”

“…Vero E6 cells are stable cell lines expressing a high level of the ACE2 receptor [49]. They were recently employed in studies to assess SARS-CoV-2 infection and replication by quantifying the virally induced CPE leading to the formation of cytolytic plaques [50][51][52][53]. Prior to antiviral testing the cytotoxicity of all samples towards Vero E6 cells was assessed, and the 50% cytotoxic concentration (CC 50 ) of the test compounds was determined.…”

The Petasites hybridus CO2 Extract (Ze 339) Blocks SARS-CoV-2 Replication In Vitro

“…Vero E6 cells are stable cell lines that express a high level of the ACE2 receptor [49]. They were recently employed in studies to assess SARS-CoV-2 infection and replication by quantifying the virally induced CPE, leading to the formation of cytolytic plaques [50][51][52][53]. Prior to antiviral testing the cytotoxicity of all samples towards Vero E6 cells, 50% cytotoxic concentration (CC 50 ) of the test compounds was determined.…”

Phytochemicals for the treatment of COVID-19

“…Berberine, another alkaloid, was observed to reduce infectious virus production but not viral RNA levels in Vero E6 cells, indicating that berberine affects stages later than genome replication (Pizzorno et al, 2020;Varghese et al, 2021). An immunofluorescence-based screening for FDA-approved drugs that inhibit viral genome replication, as indicated by dsRNA production, revealed bromhexine and reserpine, and two antiarrhythmic drugs with antimalarial activity, hydroquinidine and quinidine, as potential anti-SARS-CoV-2 agents (Ku et al, 2020). Other antimalarial alkaloids (quinacrine and quinine) have also been reported to inhibit SARS-CoV-2 infection in vitro (Große et al, 2021;Salas Rojas et al, 2021).…”