Species differences in metabolism of EPZ015666, an oxetane-containing protein arginine methyltransferase-5 (PRMT5) inhibitor

Rioux, Nathalie; Duncan, Kenneth W.; Lantz, Ronald J; Miao, Xiaofei; Chan-Penebre, Elayne; Moyer, Mikel P.; Munchhof, Michael J.; Copeland, Robert A.; Chesworth, Richard; Waters, Nigel J.

doi:10.3109/00498254.2015.1072253

Cited by 16 publications

(15 citation statements)

References 17 publications

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“…AZD1979 is a melanin-concentrating hormone receptor 1 antagonist containing a spiro oxetanylazetidinyl moiety as a building block. Contrary to the reported P450-mediated oxidative ring scission of oxetanes (Stepan et al, 2011;Rioux et al, 2016), our studies have shown that the net addition of water to AZD1979 to form M1 is a non-P450 enzyme-catalyzed reaction. Although the final diol products from these oxetanes are analogous, the mechanisms that lead to their formation are clearly different.…”

Section: Discussioncontrasting

confidence: 46%

See 1 more Smart Citation

Discovery of a Novel Microsomal Epoxide Hydrolase-Catalyzed Hydration of a Spiro Oxetane

Hayes

Grönberg

et al. 2016

Drug Metabolism and Disposition

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Oxetane moieties are increasingly being used by the pharmaceutical industry as building blocks in drug candidates because of their pronounced ability to improve physicochemical parameters and metabolic stability of drug candidates. The enzymes that catalyze the biotransformation of the oxetane moiety are, however, not well studied. The in vitro metabolism of a spiro oxetane-containing compound AZD1979 [(3-(4-(2-oxa-6-azaspiro[3.3]heptan-6-ylmethyl)phenoxy)azetidin-1-yl)(5-(4-ethoxyphenyl)-1,3,4-oxadiazol-2-yl)methanone] was studied and one of its metabolites, M1, attracted our interest because its formation was NAD(P)H independent. The focus of this work was to elucidate the structure of M1 and to understand the mechanism(s) of its formation. We established that M1 was formed via hydration and ring opening of the oxetanyl moiety of AZD1979. Incubations of AZD1979 using various human liver subcellular fractions revealed that the hydration reaction leading to M1 occurred mainly in the microsomal fraction. The underlying mechanism as a hydration, rather than an oxidation reaction, was supported by the incorporation of 18 O from H 2 18O into M1. Enzyme kinetics were performed probing the formation of M1 in human liver microsomes. The formation of M1 was substantially inhibited by progabide, a microsomal epoxide hydrolase inhibitor, but not by trans-4-[4-(1-adamantylcarbamoylamino)cyclohexyloxy]-benzoic acid, a soluble epoxide hydrolase inhibitor. On the basis of these results, we propose that microsomal epoxide hydrolase catalyzes the formation of M1. The substrate specificity of microsomal epoxide hydrolase should therefore be expanded to include not only epoxides but also the oxetanyl ring system present in AZD1979.

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Section: Discussioncontrasting

confidence: 46%

“…However, only a limited number of studies have been published on the metabolism of oxetanes. Rioux et al (2016) reported a CYP2D-and CYP3A-mediated oxidative ring scission pathway of a 3-substituted dx.doi.org/10.1124/dmd.116.071142. s This article has supplemental material available at dmd.aspetjournals.org.…”

Section: Introductionmentioning

confidence: 99%

Discovery of a Novel Microsomal Epoxide Hydrolase-Catalyzed Hydration of a Spiro Oxetane

Hayes

Grönberg

et al. 2016

Drug Metabolism and Disposition

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“…Further PK studies revealed that at 100 mg/kg in mouse, the unbound plasma concentration was equivalent to or above, the methyl mark IC 90 for a period of 12 h, thus suggesting that BID dosing of EPZ015666 could effectively inhibit PRMT5 in vivo (Figure 4). Additional species PK and ADME characterization data on EPZ015666 were reported by Rioux et al 17 In summary, we have outlined the medicinal chemistry strategies employed in the optimization of a submicromolar HTS hit (1) to the selection of a potent in vivo tool compound to evaluate the pharmacology of PRMT5 inhibition. Early SAR exploration around the THIQ motif confirmed the contribution of the cation−π interaction with cofactor SAM and was thus retained within the series as a key binding interaction.…”

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confidence: 99%

Structure and Property Guided Design in the Identification of PRMT5 Tool Compound EPZ015666

Duncan

Rioux

Boriack-Sjodin

et al. 2015

ACS Med. Chem. Lett.

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120

108

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ABSTRACT:The recent publication of a potent and selective inhibitor of protein methyltransferase 5 (PRMT5) provides the scientific community with in vivo-active tool compound EPZ015666 (GSK3235025) to probe the underlying pharmacology of this key enzyme. Herein, we report the design and optimization strategies employed on an initial hit compound with poor in vitro clearance to yield in vivo tool compound EPZ015666 and an additional potent in vitro tool molecule EPZ015866 (GSK3203591). KEYWORDS:Methyltransferase, PRMT5, property based optimization, structure guided design T he mammalian protein arginine methyltransferases are a group of nine enzymes that perform N G -mono methylation-, asymmetric-, or symmetric dimethylation of arginine residues on a range of nuclear and cytoplasmic protein substrates.1 One member of this group, PRMT5, is capable of performing methylation of up to two methyl groups and is currently believed to be the predominant enzyme for symmetric dimethylation. PRMT5 may play an important role in tumorigenesis and is upregulated in several human malignancies.2−8 The mechanism behind the cell-transforming capabilities of PRMT5 has been postulated to have roles in cell death, cell-cycle progression and cell growth, and proliferation and is still under investigation.9 Whether PRMT5 drives tumorigenesis by direct signal transduction, regulating gene expression, or by some other mechanism is generally unknown, although recent studies highlight a dependency on PRMT5 as part of the spliceosomal machinery with Sm proteins, particularly for MYC-driven tumors. 10EPZ015666 has recently been characterized as a potent inhibitor and in vivo tool compound of PRMT5.11 This compound is the first inhibitor to be described with a well characterized correlation between inhibition of PRMT5 enzyme and reduction of known substrate products including symmetric-dimethylated SmD3, coupled with a corresponding effect on tumor growth inhibition. In addition, structural biology studies highlighted a unique cation−π binding mode involving the tetrahydroisoquinoline (THIQ) containing chemical series as exemplified in the EPZ015666:PRMT5:-MEP50 cocrystal complex (PDB Codes: 4X60, 4X61). Herein we describe the medicinal chemistry optimization (Figure 1) in the development of tool compound EPZ015666.Compound 1 was recently described 11 as a hit identified from a 370 K member diversity high throughput screening (HTS) campaign, with modest inhibitory activity against PRMT5. Scheme 1 shows the synthetic route employed for the optimization of 1, as it enabled identification of SAR around the THIQ group at the penultimate step. Retaining the cyclopentylamino motif, a range of amines were used to open epoxide intermediate 5, providing the amino alcohol derivatives shown after boc-deprotection. No increase in activity was observed from this set, however, in comparison with the original hit compound (Scheme 1B). The contribution of the THIQ mediated cation−π interaction is apparent from this early data set with a number of non-THIQ co...

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“…Accordingly, the symmetric methylation level in the xenograft tumors was decreased in a dose-dependent manner. A following study [109] reports that EPZ015666 exhibits low clearance in human, mouse and rat liver microsomes and higher clearance in dog liver microsomes as well as hepatocytes. This study provides important information about similarity of the metabolism profiles between different organisms and human, which may facilitate the transition from preclinical models to human test.…”

Section: Prmt5-specific Inhibitorsmentioning

confidence: 99%

Small Molecule Inhibitors of Protein Arginine Methyltransferases

Qian

et al. 2016

Expert Opinion on Investigational Drugs

106

115

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Introduction Arginine methylation is an abundant posttranslational modification occurring in mammalian cells and catalyzed by protein arginine methyltransferases (PRMTs). Misregulation and aberrant expression of PRMTs are associated with various disease states, notably cancer. PRMTs are prominent therapeutic targets in drug discovery. Areas covered The authors provide an updated review of the research on the development of chemical modulators for PRMTs. Great efforts are seen in screening and designing potent and selective PRMT inhibitors, and a number of micromolar and submicromolar inhibitors have been obtained for key PRMT enzymes such as PRMT1, CARM1, and PRMT5. The authors provide a focus on their chemical structures, mechanism of action, and pharmacological activities. Pros and cons of each type of inhibitors are also discussed. Expert opinion Several key challenging issues exist in PRMT inhibitor discovery. Structural mechanisms of many PRMT inhibitors remain unclear. There lacks consistency in potency data due to divergence of assay methods and conditions. Physiologically relevant cellular assays are warranted. Substantial engagements are needed to investigate pharmacodynamics and pharmacokinetics of the new PRMT inhibitors in pertinent disease models. Discovery and evaluation of potent, isoform-selective, cell-permeable and in vivo-active PRMT modulators will continue to be an active arena of research in years ahead.

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Species differences in metabolism of EPZ015666, an oxetane-containing protein arginine methyltransferase-5 (PRMT5) inhibitor

Cited by 16 publications

References 17 publications

Discovery of a Novel Microsomal Epoxide Hydrolase-Catalyzed Hydration of a Spiro Oxetane

Discovery of a Novel Microsomal Epoxide Hydrolase-Catalyzed Hydration of a Spiro Oxetane

Structure and Property Guided Design in the Identification of PRMT5 Tool Compound EPZ015666

Small Molecule Inhibitors of Protein Arginine Methyltransferases

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