Figure EV6. Antiviral activity of compounds in cells.

• A
  Vero cells were tested for compatibility with DMSO concentrations, revealing low toxicity at concentrations < 0.1% (v/v) but more substantial cytotoxicity at higher concentrations (0.3% and above). This limited the range of compound concentrations useable for infection studies; at concentrations up to 11 μM, 0.1% (v/v) DMSO was used as vehicle, at 33 μM compound concentration, 0.3% (v/v) DMSO was used. Higher concentrations of compound could not be tested due to this limitation. Data represent mean values ± SD from n = 12 technical replicates pooled from n = 2 independent experiments.
• B
  Toxicity titration of compounds rac3j, rac3k and rac5c on Vero cells. At 33 μM compound concentration, cellular toxicity is ˜ 25%. ABT‐199 and S63845 are death‐inducing compounds (Souers et al, 2013; Kotschy et al, 2016) used as a control. Data are shown as mean ± SD with n = 12 technical replicates pooled from n = 2 independent experiments for rac3j, rac3k and the controls (ABT‐199 and S63845) and n = 18 technical replicates pooled from n = 3 independent experiments for rac5c.
• C, D
  CPE assays to assess cell killing activity of SARS‐CoV-2 in Vero cells left untreated (DMSO control) or treated with compounds rac3j (C) and rac3k (D). One experiment with 6 biological replicates is shown (black line, mean), and compared to HCQ‐treated cells (10 μM) with pooled data from 2 experiments with n = 6, as in Fig 6B. The 33 μM compound concentration was performed at 0.3% (v/v) DMSO and significantly rescued infected cells despite underlying cytotoxicity in Vero cells (see A, B).
• E, F
  TCID50 analysis of infectious virus for rac3j, rac3k, from the experiments performed in (C) and (D), respectively. Data are representative of 1 experiment out of 2, with n = 6 per experiment, bars represent the mean TCID50 value with error bars showing SD. HCQ control was performed within the same experiment.