Figure 7. mTOR inhibitors nearly abolish human coronavirus OC43 transcription, protein synthesis and generation of infectious progeny virus. A549 cells were infected with human coronavirus (HCoV) OC43 for 1.5 h and subsequently treated with different mTOR inhibitors, AZD-8055, Torin-1, or Torkinib, at varying concentrations. Protein (m.o.i = 1), and viral RNA (m.o.i = 0.3) analyses were measured at 24 h post infection. Asterisk ( * ) or non-significant (ns) is compared to vehicle (Veh) control. ( A ) Western blot of cellular and viral proteins at presence of AZD-8055. ( B ) Quantification of viral protein spike S displayed in A (n = 3). (C ) Western blot of cellular and viral proteins at presence of Torin-1. ( D ) Quantification of viral protein spike S displayed in C (n = 3). (E ) Western blot of cellular and viral proteins at presence of Torkinib. ( F ) Quantification of viral protein spike S displayed in E (n = 3). ( G – M ) Quantification of viral RNA expression at presence of indicated concentration of mTOR inhibitors (n = 3). ( G ) non-structural protein 2 NS2; ( H ) hemagglutinin-esterase HE; ( I ) spike surface glycoprotein S; ( J ) envelope protein E; ( K ) membrane protein M; ( L ) nucleocapsid protein N; ( M ) replicase polyprotein ORF1ab. ( N ) TCID 50 quantification of virus progeny at presence of indicated concentration of mTOR inhibitors (n = 2). Error bars, SEM; *, p < 0.05; **, p < 0.01; ***, p < 0.001; ****, p < 0.0001; n.s.