Niclosamide and Hydroxychloroquine affect Spike-pseudovirus transduction in a dose-dependent manner.

A: Quantification in A shows the normalized percentage transduction of Spike-pseudo virus across different concentrations of Niclosamide for incubation times of 8hours(i) and 4hours(ii) in AGS cells. Both the inhibitor and the virus were removed beyond the indicated times and cells were incubated with the continued presence of 100nM Niclosamide or 0.005% DMSO until termination. Images shown in Fig 7E and dose-response curve depicted in Fig 7F are related to the experiment in S9A(i). Number of repeats = 3 for each concentration of Niclosamide except 2 and 4 for 0.1μM and 0.2μM, respectively for the 8 hours set and 1 for 0.1μM Niclosamide in the 4 hours set. For the experiment in Fig 7G in AGS-ACE2 cells, number of repeats = 3 for each concentration of Niclosamide. p-value table is indicated in S1 Table. B, C: AGS cells pulsed with pH-sensitive (FITC) dextran for 2 hours and chased for 1 hour with Control or 50μM HCQ and imaged live. HCQ increases pH only slightly. pH maps are shown in B and quantification in C. Numbers of repeats: Control = 22, HCQ = 2. D, E: Images of AGS cells expressing the reporter mCherry protein upon transduction with Spike-pseudovirus in D and quantification in E show a dose-dependent reduction in transduction efficiency upon treatment with HCQ at the two concentrations tested compared to control (p-value < e-66 for HCQ 25μM, p-value < e-96 for HCQ 50μM). Number of repeats = 4 for control (0% DMSO) and 3 each for each concentration of HCQ. F: For the experiment described in Fig 7H, Quantification in S9F shows the normalized percentage transduction across indicated concentrations of Niclosamide in combination with indicated Hydroxychloroquine concentration of 2μM(i), 5μM(ii) and 10μM(iii). The percentage of cell viability for each condition is also indicated. Number of repeats = 2 for HCQ 5μM + Niclosamide 1μM combination and 3 each for all other combinations. p-value table is indicated in S1 Table. Data representation in A, E and F are as described in Fig 3 and C as described in Fig 2. Scale bar: 100μm (B).

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