P14
High-throughput drug screening allowed identification of entry inhibitors specifically targeting different routes of SARS-CoV-2 Delta and Omicron
M Kuzikov¹ ² ³ J Woens⁴ A Zaliani¹ ² J Hambach⁵ T Eden⁵ B Fehse⁴ B Ellinger*¹ ² K Riecken*⁴
1:Fraunhofer Institute for Translational Medicine and Pharmacology ITMP, Schnackenburgallee 114, 22525 Hamburg, Germany; 2:Fraunhofer Cluster of Excellence for Immune-Mediated Diseases CIMD, Theodor-Stern-Kai 7, 60596 Frankfurt am Main, Germany; 3:Department of Life Sciences and Chemistry, Jacobs University Bremen, Bremen, Germany; 4:Research Department Cell and Gene Therapy, Department of Stem Cell Transplantation, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany; 5:Institute of Immunology, University Medical Center Hamburg-Eppendorf, 25462 Hamburg, Germany
*Contributed equally; correspondence to bernhard.ellinger@itmp.fraunhofer.de, k.riecken@uke.uni-hamburg.de
The Severe Acute Respiratory Syndrome Coronavirus type 2 (SARS-CoV-2) pandemic is a global health threat. The virus has continuously evolved, resulting in the manifestation of several variants of concern (VOCs) that are repeatedly burdening societies and health care systems worldwide. To study mechanisms of viral entry and potentially identify specific inhibitors, we pseudotyped lentiviral vectors with different SARS-CoV-2 VOC spike variants (D614G, Alpha, Beta, Delta, Omicron), responsible for receptor binding and membrane fusion. These SARS-CoV-2 lentiviral pseudoviruses were used to screen a repurposing library containing 774 FDA-approved drugs. For the assay we decided to use CaCo2 cells that equally allow cell entry through both the direct membrane fusion pathway mediated by TMPRSS2 and the endocytosis pathway mediated by cathepsin-L. Accordingly, we included TMPRSS2 inhibitor camostat and cathepsin-L inhibitor E64d as positive controls. Our data showed that the various VOCs differ in their preferences for cell entry. Notably, Omicron singled out by relying primarily on the endocytosis pathway. Some of the active molecules we identified belong to the class of microtubule binders, but the group which showed stronger differences in their potency to inhibit certain SARS-CoV-2 VOCs included antagonists of G-protein coupled receptors, such as Chlorpromazine, with highest activity against the Omicron pseudovirus. In conclusion, our data provide new insights in different entry preferences of SARS-CoV-2 VOCs, which might help to identify new drug targets.