Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the coronavirus disease 2019 (COVID-19) pandemic. The virus still spreads globally through human-to-human transmission. Nevertheless, there are no specific treatments clinically approved. This study aimed to compare antiviral activity of gemcitabine and its analogue 2′-fluoro-2′-deoxycytidine (2FdC) against SARS-CoV-2 as well as cytotoxicity in vitro. Fluorescent image-based antiviral assays revealed that gemcitabine was highly potent, with a 50% effective concentration (EC 50 ) of 1.2 μM, more active than the well-known nucleoside monophosphate remdesivir (EC 50 = 35.4 μM). In contrast, 2FdC was marginally active (EC 50 = 175.2 μM). For all three compounds, the 50% cytotoxic concentration (CC 50 ) values were over 300 μM toward Vero CCL-81 cells. Western blot and quantitative reverse-transcription polymerase chain reaction analyses verified that gemcitabine blocked viral protein expression in virus-infected cells, not only Vero CCL-81 cells but also Calu-3 human lung epithelial cells in a dose-dependent manner. It was found that gemcitabine has a synergistic effect when combined with remdesivir. This report suggests that the difluoro group of gemcitabine is critical for the antiviral activity and that its combination with other evaluated antiviral drugs, such as remdesivir, could be a desirable option to treat SARS-CoV-2 infection.
【저자키워드】 SARS-CoV-2, antiviral activity, gemcitabine, 2′-fluoro-2′-deoxycytidine, 【초록키워드】 COVID-19, coronavirus disease, severe acute respiratory syndrome coronavirus 2, Coronavirus disease 2019, coronavirus, pandemic, SARS-COV-2 infection, antiviral drugs, Remdesivir, cytotoxicity, in vitro, antiviral activity, severe acute respiratory syndrome Coronavirus, virus, Spread, polymerase chain reaction, Viral, western blot, human lung, Antiviral assays, epithelial cells, gemcitabine, respiratory, expression, Quantitative, Critical, Calu-3, compounds, antiviral assay, Combination, Concentration, Analysis, epithelial cell, causative agent, Chain Reaction, synergistic effect, acute respiratory syndrome, Viral protein, deoxycytidine, acute respiratory syndrome coronavirus, infected cells, virus-infected cells, dose-dependent manner, treat, human-to-human transmission, Calu, specific treatment, Vero CCL-81 cells, human lung epithelial cells, monophosphate, 50% effective concentration, synergistic, polymerase chain, blocked, clinically, evaluated, approved, Vero CCL-81 cell, 【제목키워드】 Remdesivir, antiviral activity, activity, gemcitabine,