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BACKGROUND: Medicines for the treatment of 2019-novel coronavirus (2019-nCoV) infections are urgently needed. However, drug screening using live 2019-nCoV requires high-level biosafety facilities, which imposes an obstacle for those institutions without such facilities or 2019-nCoV. This study aims to repurpose the clinically approved drugs for the treatment of coronavirus disease 2019 (COVID-19) in a 2019-nCoV-related coronavirus model. METHODS: A 2019-nCoV-related pangolin coronavirus GXP2V/pangolin/2017/Guangxi was described. Whether GXP2V uses angiotensin-converting enzyme 2 (ACE2) as the cell receptor was investigated by using small interfering RNA (siRNA) -mediated silencing of ACE2. The pangolin coronavirus model was used to identify drug candidates for treating 2019-nCoV infection. Two libraries of 2406 clinically approved drugs were screened for their ability to inhibit cytopathic effects on Vero E6 cells by GXP2V infection. The anti-viral activities and anti-viral mechanisms of potential drugs were further investigated. Viral yields of RNAs and infectious particles were quantified by quantitative real-time polymerase chain reaction (qRT-PCR) and plaque assay, respectively. RESULTS: The spike protein of coronavirus GXP2V shares 92. 2% amino acid identity with that of 2019-nCoV isolate Wuhan-hu-1, and uses ACE2 as the receptor for infection just like 2019-nCoV. Three drugs, including cepharanthine (CEP), selamectin, and mefloquine hydrochloride, exhibited complete inhibition of cytopathic effects in cell culture at 10 μmol/L. CEP demonstrated the most potent inhibition of GXP2V infection, with a concentration for 50% of maximal effect EC50 of 0. 98 μmol/L. The viral RNA yield in cells treated with 10 μmol/L CEP was 15, 393-fold lower than in cells without CEP treatment (6. 48 ± 0. 02 × 10vs. 1. 00 ± 0. 12, t = 150. 38, P < 0. 001) at 72 h post-infection (p. i. ). Plaque assays found no production of live viruses in media containing 10 μmol/L CEP at 48 h p. i. Furthermore, we found CEP had potent anti-viral activities against both viral entry (0. 46 ± 0. 12, vs. 1. 00 ± 0. 37, t = 2. 42, P < 0. 05) and viral replication (6. 18 ± 0. 95 × 10vs. 1. 00 ± 0. 43, t = 3. 98, P < 0. 05). CONCLUSIONS: Our pangolin coronavirus GXP2V is a workable model for 2019-nCoV research. CEP, selamectin, and mefloquine hydrochloride are potential drugs for treating 2019-nCoV infection. Our results strongly suggest that CEP is a wide-spectrum inhibitor of pan-betacoronavirus, and further study of CEP for treatment of 2019-nCoV infection is warranted.
Fan et al. (Fri,) studied this question.