Hydroxychloroquine sulphate

DMSO, dexamethasone (D4902), ribavirin (R9644), lopinavir (SML0491), ritonavir (SML1222), hydroxychloroquine sulphate (HO915), chloroquine diphosphate (C6628), and azithromycin dihydrate (A9834) were supplied by Sigma-Aldrich (Overijse, Belgium). In the case of the latter 3 drugs, the salt forms were purchased to avoid limitations due to the low solubility of the drugs. Remdesivir (30354-10) was purchased from Sanbio (Uden, The Netherlands), and favipiravir (FF29069) was obtained from Biosynth Carbosynth (Compton, United Kingdom). The peptide mimetic ¹⁰Panx1 was synthesised in-house by means of solid-phase peptide synthesis with a purity of >98%. Lanthanum trichloride was supplied by Merck Chemical n.v./s.a. (Overijse, Belgium). All other reagents were obtained from various suppliers at the highest analytical grade possible. Each drug was dissolved in the respective solvent (Table 1).

For autophagy modulation, FaDu cells were treated for 24 h with 5 nM bafilomycin A1 (Sigma-Aldrich, B1793), 50 µM of hydroxychloroquine sulphate (Sigma-Aldrich, H0915), 100 µM of CPD18 (Calbiochem), 50 nM of autophinib (Sigma, SML2632), 10 µM of EACC (MedChemExpress), 200 nM of rapamycin (Sigma-Aldrich, R0395), 3 nM of Torin-1 (MedChemExpress), or 30 nM of NVP-BEZ235 (MedChemExpress). To induce starvation, cells were cultured in DMEM F12 without glutamine and without FBS (Biosera). Modulation of autophagy did not reduce the viability of FaDu cells (the viability ranged 98.1 to 99.9% across treatments).