Novel PD-L1-Targeted Phenyl-Pyrazolone Derivatives with Antioxidant Properties

• Published in: Molecules (Basel, Switzerland) Switzerland), 2023-04, Vol.28 (8), p.3491
• Main Authors: Regnault, Romain, Klupsch, Frédérique, El-Bouazzati, Hassiba, Magnez, Romain, Le Biannic, Raphaël, Leleu-Chavain, Natascha, Ahouari, Hania, Vezin, Hervé, Millet, Régis, Goossens, Jean-François, Thuru, Xavier, Bailly, Christian
• Format: Article
• Language: English
• Subjects: 4-Hydroxynonenal; Adducts; aldehyde reactivity; Aldehydes; antioxidant; Antioxidants; Antioxidants - metabolism; Antioxidants - pharmacology; cancer; Cancer therapies; Cell growth; Cell proliferation; Chemical properties; Chemical Sciences; Dimerization; Drug dosages; Electron paramagnetic resonance; Electron spin resonance; Free radicals; Free radicals (Chemistry); immune checkpoint; Immune checkpoint inhibitors; Immunotherapy; Ligands; Lipid peroxidation; Lipids; Mass spectrometry; Mass spectroscopy; or physical chemistry; PD-1 protein; PD-L1 binding; PD-L1 protein; Peroxidation; Phosphatase; Programmed Cell Death 1 Receptor - metabolism; Proteins; pyrazolone; Pyrazolones; Scavenging; SHP-2 protein; Signal Transduction; Theoretical and
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules28083491

Orally-active anticancer small molecules targeting the PD-1/PD-L1 immune checkpoint are actively searched. Phenyl-pyrazolone derivatives with a high affinity for PD-L1 have been designed and characterized. In addition, the phenyl-pyrazolone unit acts as a scavenger of oxygen free radicals, providing antioxidant effects. The mechanism is known for the drug edaravone ( ) which is also an aldehyde-reactive molecule. The present study reports the synthesis and functional characterization of new molecules ( - ) with an improved anti-PD-L1 activity. The leading fluorinated molecule emerges as a potent checkpoint inhibitor, avidly binding to PD-L1, inducing its dimerization, blocking PD-1/PD-L1 signaling mediated by phosphatase SHP-2 and reactivating the proliferation of CTLL-2 cells in the presence of PD-L1. In parallel, the compound maintains a significant antioxidant activity, characterized using electron paramagnetic resonance (EPR)-based free radical scavenging assays with the probes DPPH and DMPO. The aldehyde reactivity of the molecules was investigated using 4-hydroxynonenal (4-HNE), which is a major lipid peroxidation product. The formation of drug-HNE adducts, monitored by high resolution mass spectrometry (HRMS), was clearly identified and compared for each compound. The study leads to the selection of compound and the dichlorophenyl-pyrazolone unit as a scaffold for the design of small molecule PD-L1 inhibitors endowed with antioxidant properties.