Radiosynthesis of [ 18 F]brequinar for in vivo PET imaging of hDHODH for potential studies of acute myeloid leukemia and cancers

• Published in: MedChemComm Vol. 15; no. 9; pp. 3147 - 3161
• Main Authors: Banka, Vinay Kumar, Sainas, Stefano, Martino, Elena, Wang, Jiacheng, Lolli, Marco Lucio, Ding, Yu-Shin
• Format: Journal Article
• Language: English
• Published: CAMBRIDGE Royal Soc Chemistry 22.07.2024; Royal Society of Chemistry; RSC
• Subjects: Acute myeloid leukemia; Autoimmune diseases; Biochemistry & Molecular Biology; Biosynthesis; Cancer; Chemistry; Chemistry, Medicinal; Clinical trials; Dihydroorotate dehydrogenase; Drug development; Fluorine isotopes; Health services; In vivo methods and tests; Leukemia; Life Sciences & Biomedicine; Medical imaging; Medical treatment; Pharmacology & Pharmacy; Positron emission; Precision medicine; Radioactive tracers; Radiolabelling; Science & Technology; DESIGN; ACID; RADIOFLUORINATION; SCAFFOLD SAR; MEDIATED F-18-FLUORINATION; DHODH INHIBITORS; DIFFERENTIATION; FLUORINATION; DIHYDROOROTATE
• ISSN: 2632-8682; 2040-2503; 2632-8682; 2040-2511
• DOI: 10.1039/D4MD00433G

Dihydroorotate dehydrogenase (DHODH), an enzyme that plays a critical role in the de novo pyrimidine biosynthesis, has been recognized as a promising target for the treatment of diseases that involve cellular proliferation, such as autoimmune diseases and cancers. Pharmacological inhibition of human DHODH (hDHODH) that offers a potential therapeutic strategy for the treatment in adult subjects with acute myeloid leukemia (AML) has recently been supported by phase I/II clinical trials for the treatment of patients with relapsed/refractory AML. To facilitate the development of optimized hDHODH inhibitors, the presence of an in vivo imaging probe that is able to demonstrate in vivo target engagement is critical and desirable. Brequinar is one of the most potent hDHODH inhibitors so far discovered. In this work, we use a copper-mediated radiofluorination (CMRF) strategy and compare the chemical design and radiosynthesis starting from either pinacole boronate p -nitrobenzyl ester (4) or tributylstannate (tin) p -nitrobenzyl ester (5), chosen for their suitability as a precursor to [ 18 F]brequinar. We report here the design, synthesis, radiolabeling and characterization of [ 18 F]brequinar, and a preliminary PET imaging study of DHODH in vivo . This study provides the strategies to create [ 18 F]brequinar, the first hDHODH inhibitor PET radiotracer, which will facilitate its use as a tool (theranostics) for hDHODH drug development and for diagnosis and monitoring therapeutic efficacy in AML and cancers.