Characterization of Reference Materials for CYP3A4 and CYP3A5

Gaedigk, Andrea; Boone, Erin C.; Turner, Amy J.; van Schaik, Ron H.N.; Chernova, Dilyara; Wang, Wendy Y.; Broeckel, Ulrich; Granfield, Caitlin A.; Hodge, Jennelle C.; Ly, Reynold C.; Lynnes, Ty C.; Mitchell, Matthew W.; Moyer, Ann M.; Oliva, Jason; Kalman, Lisa V.

doi:10.1016/j.jmoldx.2023.06.005

Cited by 8 publications

(2 citation statements)

References 37 publications

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“…A role, if any, of this isoform in M8OI metabolism therefore cannot currently be determined. CYP3A4 is generally considered the major expressed human liver CYP and proposed to be involved in the metabolism of between 30 and 64% of clinically prescribed drugs [ 33 ]. Given these facts and that supersomes containing CYP3A4 are the most active in the metabolism of M8OI, it is likely that in adult humans, CYP3A4 would make a major contribution to the metabolism of M8OI.…”

Section: Discussionmentioning

confidence: 99%

Ionic Liquid 1-Octyl-3-Methylimidazolium (M8OI) Is Mono-Oxygenated by CYP3A4 and CYP3A5 in Adult Human Liver

Leitch,

Abdelghany,

Charlton

et al. 2024

JoX

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Environmental sampling around a landfill site in the UK previously identified the methylimidazolium ionic liquid, 1-octyl-3-methylimidazolium (M8OI), in the soil. More recently, M8OI was shown to be detectable in sera from 5/20 PBC patients and 1/10 controls and to be oxidised on the alkyl chain in the human liver. The objective of this study was to examine the metabolism of M8OI in humans in more detail. In human hepatocytes, M8OI was mono-oxygenated to 1-(8-Hydroxyoctyl)-3-methyl-imidazolium (HO8IM) then further oxidised to 1-(7-carboxyheptyl)-3-methyl-1H-imidazol-3-ium (COOH7IM). The addition of ketoconazole—in contrast to a range of other cytochrome P450 inhibitors—blocked M8OI metabolism, suggesting primarily CYP3A-dependent mono-oxygenation of M8OI. Hepatocytes from one donor produced negligible and low levels of HO8IM and COOH7IM, respectively, on incubation with M8OI, when compared to hepatocytes from other donors. This donor had undetectable levels of CYP3A4 protein and low CYP3A enzyme activity. Transcript expression levels for other adult CYP3A isoforms—CYP3A5 and CYP3A43—suggest that a lack of CYP3A4 accounted primarily for this donor’s low rate of M8OI oxidation. Insect cell (supersome) expression of various human CYPs identified CYP3A4 as the most active CYP mediating M8OI mono-oxygenation, followed by CYP3A5. HO8IM and COOH7IM were not toxic to human hepatocytes, in contrast to M8OI, and using a pooled preparation of human hepatocytes from five donors, ketoconazole potentiated M8OI toxicity. These data demonstrate that CYP3A initiates the mono-oxygenation and detoxification of M8OI in adult human livers and that CYP3A4 likely plays a major role in this process.

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Section: Discussionmentioning

confidence: 99%

Ionic Liquid 1-Octyl-3-Methylimidazolium (M8OI) Is Mono-Oxygenated by CYP3A4 and CYP3A5 in Adult Human Liver

Leitch,

Abdelghany,

Charlton

et al. 2024

JoX

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“…Clinical genotyping was performed using the PharmacoScan Assay Kit and analyzed with the Axiom Analysis Suite 5.1.1.1 (Thermo Fisher Scientific) as previously described. 10 The assay interrogates 53 DPYD variants, including c.1129‐5923C>G and c.1236G>A. DPYD genotype calls were made using the commercially released allele translation table (r9; Thermo Fisher Scientific; Table S1 ).…”

Section: Methodsmentioning

confidence: 99%

Updated DPYDHapB3 haplotype structure and implications for pharmacogenomic testing

Turner,

Haidar,

Yang

et al. 2024

Clinical Translational Sci

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The DPYD gene encodes dihydropyrimidine dehydrogenase, the rate‐limiting enzyme for the metabolism of fluoropyrimidines 5‐fluorouracil and capecitabine. Genetic variants in DPYD have been associated with altered enzyme activity, therefore accurate detection and interpretation is critical to predict metabolizer status for individualized fluoropyrimidine therapy. The most commonly observed deleterious variation is the causal variant linked to the previously described HapB3 haplotype, c.1129‐5923C>G (rs75017182) in intron 10, which introduces a cryptic splice site. A benign synonymous variant in exon 11, c.1236G>A (rs56038477) is also linked to HapB3 and is commonly used for testing. Previously, these SNPs have been reported to be in perfect linkage disequilibrium (LD); therefore, c.1236G>A is often utilized as a proxy for the function‐altering intronic variant. Clinical genotyping of DPYD identified a patient who had c.1236G>A, but not c.1129‐5923C>G, suggesting that these two SNPs may not be in perfect LD as previously assumed. Additional individuals with c.1236G>A, but not c.1129‐5923C>G, were identified in the Children's Mercy Data Warehouse and the All of Us v7 cohort substantiating incomplete SNP linkage. Consequently, testing only c.1236G>A can generate false‐positive results in some cases and lead to suboptimal dosing that may negatively impact patient therapy and prospect of survival. Our data shows that DPYD genotyping should include the functional variant c.1129‐5923C>G, and not the c.1236G>A proxy, to accurately predict DPD activity.

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