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Kitel R, Rodríguez I, del Corte X, Atmaj J, Żarnik M, Surmiak E, Muszak D, Magiera-Mularz K, Popowicz GM, Holak TA, Musielak B. Exploring the Surface of the Ectodomain of the PD-L1 Immune Checkpoint with Small-Molecule Fragments. ACS Chem Biol 2022; 17:2655-2663. [PMID: 36073782 PMCID: PMC9486809 DOI: 10.1021/acschembio.2c00583] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Development of small molecules targeting the PD-L1/PD-1 interface is advancing both in industry and academia, but only a few have reached early-stage clinical trials. Here, we take a closer look at the general druggability of PD-L1 using in silico hot spot mapping and nuclear magnetic resonance (NMR)-based characterization. We found that the conformational elasticity of the PD-L1 surface strongly influences the formation of hot spots. We deconstructed several generations of known inhibitors into fragments and examined their binding properties using differential scanning fluorimetry (DSF) and protein-based nuclear magnetic resonance (NMR). These biophysical analyses showed that not all fragments bind to the PD-L1 ectodomain despite having the biphenyl scaffold. Although most of the binding fragments induced PD-L1 oligomerization, two compounds, TAH35 and TAH36, retain the monomeric state of proteins upon binding. Additionally, the presence of the entire ectodomain did not affect the binding of the hit compounds and dimerization of PD-L1. The data demonstrated here provide important information on the PD-L1 druggability and the structure-activity relationship of the biphenyl core moiety and therefore may aid in the design of novel inhibitors and focused fragment libraries for PD-L1.
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Affiliation(s)
- Radoslaw Kitel
- Faculty
of Chemistry, Organic Chemistry Department, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland
| | - Ismael Rodríguez
- Faculty
of Chemistry, Organic Chemistry Department, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland
| | - Xabier del Corte
- Departamento
de Química Orgánica I, Centro de Investigación
y Estudios Avanzados “Lucio Lascaray” − Facultad
de Farmacia, University of the Basque Country, UPV/EHU Paseo de la Universidad
7, 01006 Vitoria-Gasteiz, Spain
| | - Jack Atmaj
- Faculty
of Chemistry, Organic Chemistry Department, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland
| | - Magdalena Żarnik
- Faculty
of Chemistry, Organic Chemistry Department, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland
| | - Ewa Surmiak
- Faculty
of Chemistry, Organic Chemistry Department, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland
| | - Damian Muszak
- Faculty
of Chemistry, Organic Chemistry Department, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland
| | - Katarzyna Magiera-Mularz
- Faculty
of Chemistry, Organic Chemistry Department, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland
| | - Grzegorz M. Popowicz
- Institute
of Structural Biology, Helmholtz Zentrum
München, Ingolstädter
Landstrasse 1, 85764 Neuherberg, Germany
| | - Tad A. Holak
- Faculty
of Chemistry, Organic Chemistry Department, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland
| | - Bogdan Musielak
- Faculty
of Chemistry, Organic Chemistry Department, Jagiellonian University, Gronostajowa 2, 30-387 Krakow, Poland,
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