Development and validation of CYP26A1 inhibition assay for high‐throughput screening

• Published in: Biotechnology journal Vol. 19; no. 6; pp. e2300659 - n/a
• Main Authors: Sakamuru, Srilatha, Ma, Dongping, Pierro, Jocylin D., Baker, Nancy C., Kleinstreuer, Nicole, Cali, James J., Knudsen, Thomas B., Xia, Menghang
• Format: Journal Article
• Language: English
• Published: Germany 01.06.2024
• Subjects: all‐trans retinoic acid (atRA); CYP26; Cytochrome P-450 Enzyme Inhibitors - pharmacology; cytochrome P450 (CYP); High-Throughput Screening Assays - methods; Humans; Reproducibility of Results; Retinoic Acid 4-Hydroxylase - genetics; Retinoic Acid 4-Hydroxylase - metabolism; retinoic acid receptor (RAR); Tretinoin - metabolism; Tretinoin - pharmacology; retinoic acid receptor (RAR); all‐trans retinoic acid (atRA); cytochrome P450 (CYP); CYP26
• ISSN: 1860-6768; 1860-7314
• DOI: 10.1002/biot.202300659

All‐trans retinoic acid (atRA) is an endogenous ligand of the retinoic acid receptors, which heterodimerize with retinoid X receptors. AtRA is generated in tissues from vitamin A (retinol) metabolism to form a paracrine signal and is locally degraded by cytochrome P450 family 26 (CYP26) enzymes. The CYP26 family consists of three subtypes: A1, B1, and C1, which are differentially expressed during development. This study aims to develop and validate a high throughput screening assay to identify CYP26A1 inhibitors in a cell‐free system using a luminescent P450‐Glo assay technology. The assay performed well with a signal to background ratio of 25.7, a coefficient of variation of 8.9%, and a Z‐factor of 0.7. To validate the assay, we tested a subset of 39 compounds that included known CYP26 inhibitors and retinoids, as well as positive and negative control compounds selected from the literature and/or the ToxCast/Tox21 portfolio. Known CYP26A1 inhibitors were confirmed, and predicted CYP26A1 inhibitors, such as chlorothalonil, prochloraz, and SSR126768, were identified, demonstrating the reliability and robustness of the assay. Given the general importance of atRA as a morphogenetic signal and the localized expression of Cyp26a1 in embryonic tissues, a validated CYP26A1 assay has important implications for evaluating the potential developmental toxicity of chemicals. Graphical and Lay Summary All‐trans retinoic acid (atRA) is essential for embryonic development and tissue homeostasis in adults. The atRA is locally generated from retinol metabolism and primarily degraded by cytochrome p450 family 26 (CYP26) enzymes. Here, we developed and validated an enzyme‐based CYP26A1 high‐throughput assay that can be used to identify CYP26A1 inhibitors by screening the chemical libraries.