Alectinib for COVID-19

Background and purpose In the past two decades, three pathogenic coronaviruses, including SARS‐CoV‐2, spilled over from natural animal reservoirs into the human population. Upon entry into infected cells, the nucleocapsid (N) protein of coronavirus becomes heavily phosphorylated within its central Ser‐Arg domain by host kinase GSK‐3, which triggers genomic RNA unpackaging and facilitates its recruitment to the replication transcription complex. Although initially considered a promising antiviral strategy, inhibiting N hyperphosphorylation requires high concentrations of kinase inhibitor and is impractical to achieve by conventional pharmacological means. Experimental approach We investigated the effect of GSK‐3 inhibition on SARS‐CoV‐2 replication in Calu‐3 and Vero E6 cells. The dose‐dependent effect of the GSK‐3 inhibitor to block N hyperphosphorylation was examined in 293T cells heterologously expressing the viral protein. Liquid chromatography–tandem mass spectrometry analysis was performed to evaluate the phosphorylation profile of the purified N protein. Key results GSK‐3 inhibition delays the release of progeny virus from infected cells. N hyperphosphorylation relies on a complex, redundant priming mechanism and exhibits strong cooperativity, which together contribute to resistance against GSK‐3 inhibitors. The N R203M and N R203K/G204R mutations—present in the delta and omicron variants of concern (VOCs), respectively—reduce the efficiency of GSK‐3‐mediated phosphorylation. We discovered a novel pharmacological tool combining niclosamide and alectinib that partially degrades GSK‐3 and restores the sensitivity of N hyperphosphorylation to the clinically tested GSK‐3 inhibitor, enzastaurin. Conclusions and implications This work provides the biochemical basis for a novel approach to treat COVID‐19 by synergistically repositioning two FDA‐approved drugs.

Recently the E protein of SARS-CoV-2 has become a very important target in the potential treatment of COVID-19 since it is known to regulate different stages of the viral cycle. There is biochemical evidence that E protein exists in two forms, as monomer and homopentamer. An in silico screening analysis was carried out employing 5852 ligands (from Zinc databases), and performing an ADMET analysis, remaining a set of 2155 compounds. Furthermore, docking analysis was performed on specific sites and different forms of the E protein. From this study we could identify that the following ligands showed the highest binding affinity: nilotinib, dutasteride, irinotecan, saquinavir and alectinib. We carried out some molecular dynamics simulations and free energy MM–PBSA calculations of the protein–ligand complexes (with the mentioned ligands). Of worthy interest is that saquinavir, nilotinib and alectinib are also considered as a promising multitarget ligand because it seems to inhibit three targets, which play an important role in the viral cycle. On the other side, saquinavir was shown to be able to bind to E protein both in its monomeric as well as pentameric forms. Finally, further experimental assays are needed to probe our hypothesis derived from in silico studies.