The anti‐HIV drug nelfinavir mesylate (Viracept) is a potent inhibitor of cell fusion caused by the SARSCoV‐2 spike (S) glycoprotein warranting further evaluation as an antiviral against COVID‐19 infections

Abstract

Severe acute respiratory syndrome coronavirus-2 (SARS CoV-2) is the causative agent of the coronavirus disease-2019 (COVID-19) pandemic. Coronaviruses enter cells via fusion of the viral envelope with the plasma membrane and/or via fusion of the viral envelope with endosomal membranes after virion endocytosis. The spike (S) glycoprotein is a major determinant of virus infectivity. Herein, we show that the transient expression of the SARS CoV-2 S glycoprotein in Vero cells caused extensive cell fusion (formation of syncytia) in comparison to limited cell fusion caused by the SARS S glycoprotein. Both S glycoproteins were detected intracellularly and on transfected Vero cell surfaces. These results are in agreement with published pathology observations of extensive syncytia formation in lung tissues of patientswith COVID-19. These results suggest that SARS CoV-2 is able to spread from cellto-cell much more efficiently than SARS effectively avoiding extracellular neutralizing antibodies. A systematic screening of several drugs including cardiac glycosides and kinase inhibitors and inhibitors of human immunodeficiency virus (HIV) entry revealed that only the FDA-approved HIV protease inhibitor, nelfinavir mesylate (Viracept) drastically inhibited S-n-and S-o-mediated cell fusion with complete inhibition at a 10-μM concentration. In-silico docking experiments suggested the possibility that nelfinavir may bind inside the S trimer structure, proximal to the S2 amino terminus directly inhibiting S-n-and S-o-mediated membrane fusion. Also, it is possible that nelfinavir may act to inhibit S proteolytic processing within cells.These results warrant further investigations of the potential of nelfinavir mesylate to inhibit virus spread at early times after SARS CoV-2 symptoms appear.

Structural insights into spike protein and its natural variants of SARS-CoV-2 found on Mexican population.

“…Nel navir in WT spike protein was placed in the HR1 region and formed hydrogens bond with K310, I312, and Q314, and hydrophobic interactions with L303, E309, G311, Y313, I664, P665 and I666 as previously reported (Fig. 7L) 31 . While Nel navir with D614 mutant was also placed on the HR1 region but interacted with some different residues than in the wild type, formed a hydrogen bond with N317, S596, K947 and Q1010 and hydrophobic interactions with Q314, F592, G593, I1013 (Fig.…”

“…Finally, to explore how these punctual mutations affect the protein-ligand binding, a molecular docking with Cepharenthine, Hydroxychloroquine, and Nel navir which are experimental reported spike ligands were performed [29][30][31] Cepharanthine showed potent antiviral activity In vitro against SARS-CoV-2, and by molecular docking, spike protein was suggested as its target. It is suggested that cepharanthine is bound to RBD, and might interfere with human ACE2 binding avoiding the anchorage of the virus to the cell 30,35 .…”

“…Nel navir is currently marketed as an anti-HIV drug, and recently it was demonstrated that inhibit the cell fusion mediated by spike protein of SARS-CoV-2, by molecular docking, it was identi ed that nel navir is placed between fusion peptide and HR1 helix near the S1/S2 cleavage site 31 . Therefore, nel navir was assayed by molecular docking against WT and mutants forms of the spike protein.…”

“…For Nelphinavir grid box was focused on residues L303, Y313, Q314, between HR1 and FP region. With a grid box size of 80 Å x 82 Å x 80 Å31 and a grid spacing of 0.375Å. Compounds and S protein were prepared using AutoDock Tools 1.5.628 .…”

Bepridil is potent against SARS-CoV-2 In Vitro

“…A cell-based study in inhibiting the SARS-CoV-2 entry indicated a 1 µM EC50 value. 26,27 However, our IC50 determination against M Pro resulted in a value of 234 ± 5 µM, highlighting that nelfivavir likely inhibits another key SARS-CoV-2 enzyme or protein or interferes with key cellular processes that are required for the SARS-CoV-2 entry into host cells. These possibilities need to be studied further.…”