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Huber AD, Poudel S, Wu J, Miller DJ, Lin W, Yang L, Bwayi MN, Rimmer MA, Gee RRF, Seetharaman J, Chai SC, Chen T. A bromodomain-independent mechanism of gene regulation by the BET inhibitor JQ1: direct activation of nuclear receptor PXR. Nucleic Acids Res 2024; 52:1661-1676. [PMID: 38084912 PMCID: PMC10899790 DOI: 10.1093/nar/gkad1175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 11/17/2023] [Accepted: 11/23/2023] [Indexed: 02/29/2024] Open
Abstract
Bromodomain and extraterminal (BET) proteins are extensively studied in multiple pathologies, including cancer. BET proteins modulate transcription of various genes, including those synonymous with cancer, such as MYC. Thus, BET inhibitors are a major area of drug development efforts. (+)-JQ1 (JQ1) is the prototype inhibitor and is a common tool to probe BET functions. While showing therapeutic promise, JQ1 is not clinically usable, partly due to metabolic instability. Here, we show that JQ1 and the BET-inactive (-)-JQ1 are agonists of pregnane X receptor (PXR), a nuclear receptor that transcriptionally regulates genes encoding drug-metabolizing enzymes such as CYP3A4, which was previously shown to oxidize JQ1. A PXR-JQ1 co-crystal structure identified JQ1's tert-butyl moiety as a PXR anchor and explains binding by (-)-JQ1. Analogs differing at the tert-butyl lost PXR binding, validating our structural findings. Evaluation in liver cell models revealed both PXR-dependent and PXR-independent modulation of CYP3A4 expression by BET inhibitors. We have characterized a non-BET JQ1 target, a mechanism of physiological JQ1 instability, a biological function of (-)-JQ1, and BET-dependent transcriptional regulation of drug metabolism genes.
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Affiliation(s)
- Andrew D Huber
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Shyaron Poudel
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Jing Wu
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Darcie J Miller
- Department of Structural Biology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Wenwei Lin
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Lei Yang
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Monicah N Bwayi
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Mary Ashley Rimmer
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Rebecca R Florke Gee
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
- Graduate School of Biomedical Sciences, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Jayaraman Seetharaman
- Department of Structural Biology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Sergio C Chai
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Taosheng Chen
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
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Florke Gee RR, Huber AD, Chen T. Regulation of PXR in drug metabolism: chemical and structural perspectives. Expert Opin Drug Metab Toxicol 2024; 20:9-23. [PMID: 38251638 PMCID: PMC10939797 DOI: 10.1080/17425255.2024.2309212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 01/19/2024] [Indexed: 01/23/2024]
Abstract
INTRODUCTION Pregnane X receptor (PXR) is a master xenobiotic sensor that transcriptionally controls drug metabolism and disposition pathways. PXR activation by pharmaceutical drugs, natural products, environmental toxins, etc. may decrease drug efficacy and increase drug-drug interactions and drug toxicity, indicating a therapeutic value for PXR antagonists. However, PXR's functions in physiological events, such as intestinal inflammation, indicate that PXR activators may be useful in certain disease contexts. AREAS COVERED We review the reported roles of PXR in various physiological and pathological processes including drug metabolism, cancer, inflammation, energy metabolism, and endobiotic homeostasis. We then highlight specific cellular and chemical routes that modulate PXR activity and discuss the functional consequences. Databases searched and inclusive dates: PubMed, 1 January 1980 to 10 January 2024. EXPERT OPINION Knowledge of PXR's drug metabolism function has helped drug developers produce small molecules without PXR-mediated metabolic liabilities, and further understanding of PXR's cellular functions may offer drug development opportunities in multiple disease settings.
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Affiliation(s)
- Rebecca R. Florke Gee
- Graduate School of Biomedical Sciences, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
- Department of Chemical Biology and Therapeutics, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Andrew D. Huber
- Department of Chemical Biology and Therapeutics, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Taosheng Chen
- Department of Chemical Biology and Therapeutics, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
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Yu X, Kojetin DJ. Go big and go home: A bulky extension makes promiscuous ligands settle down. Structure 2023; 31:1520-1522. [PMID: 38065074 DOI: 10.1016/j.str.2023.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 11/04/2023] [Accepted: 11/05/2023] [Indexed: 12/18/2023]
Abstract
Synthetic ligands often show undesired polypharmacology, affecting the function of multiple targets. In this issue of Structure, Huber et al. developed a PXR-specific agonist based on a promiscuous ligand. Their structure-guided approach exploited the malleability of the PXR ligand-binding pocket, which unlike other nuclear receptors could accommodate bulkier ligands.
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Affiliation(s)
- Xiaoyu Yu
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA
| | - Douglas J Kojetin
- Department of Biochemistry, Vanderbilt University, Nashville, TN 37232, USA; Center for Structural Biology; Institute of Chemical Biology; Vanderbilt-Ingram Cancer Center; Vanderbilt Brain Institute; Center for Applied AI in Protein Dynamics; Vanderbilt University, Nashville, TN 37232, USA.
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