From Virtual Screens to Cellular Target Engagement: New Small Molecule Ligands for the Immune Checkpoint LAG‑3

• Published in: ACS medicinal chemistry letters 2024-11, Vol.15 (11), p.1884-1890
• Main Authors: Fuchs, Natalie, Calvo-Barreiro, Laura, Talagayev, Valerij, Pach, Szymon, Wolber, Gerhard, Gabr, Moustafa T.
• Format: Article
• Language: English
• ISSN: 1948-5875; 1948-5875
• DOI: 10.1021/acsmedchemlett.4c00350

Herein, we performed a virtual screening study to discover new scaffolds for small molecule-based ligands of the immune checkpoint lymphocyte-activation gene 3 (LAG-3). Molecular dynamics (MD) simulations using the LAG-3 structure revealed two putative binding sites for small molecules: the antibody interface and the lipophilic canyon. A 3D pharmacophore screening resulted in the identification of potential ligands for these binding sites and afforded a library of 25 compounds. We then evaluated the screening hits for LAG-3 binding via microscale thermophoresis (MST) and surface plasmon resonance (SPR). Our biophysical screening identified two binders with K D values in the low micromolar range, compounds 3 (antibody interface) and 25 (lipophilic canyon). Furthermore, we investigated the ability of LAG-3 hits to engage LAG-3 on a cellular level using a cellular thermal shift assay (CETSA). In summary, compound 3 shows potential as a lead but is not yet a development candidate.