From Genotype to Phenotype: Cytochrome P450 2D6-Mediated Drug Clearance in Humans

Gao, Jie; Tian, Xin; Zhou, Jun; Cui, Minghua; Zhang, Haifeng; Gao, Na; Wen, Qiang; Qiao, Huan

doi:10.1021/acs.molpharmaceut.6b00920

Cited by 13 publications

(10 citation statements)

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“…It is well recognized that interindividual variations in drug response, including a lack of efficacy and adverse drug reactions represent the major challenges for personalized medicine. Although a drug effect is complex and depends on many factors, some human gene polymorphisms already have been associated with substantial differences in the metabolism or effects of drugs [28], and some are now being used to predict toxic metabolite-related disease or a clinical response [29][30][31][32][33][34][35]_ENREF_1. _ENREF_1However, as the principal electron donor for the drug metabolizing CYPs, little is known about the effect of POR gene polymorphisms on the activities of CYPs with different genotypes.…”

Section: Discussionmentioning

confidence: 99%

Effect of P450 Oxidoreductase Polymorphisms on the Metabolic Activities of Ten Cytochrome P450s Varied by Polymorphic CYP Genotypes in Human Liver Microsomes

Fang¹,

Gao²,

Tian³

et al. 2018

Cell Physiol Biochem

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Background/ Aims: Little is known about the effect of P450 oxidoreductase (POR) gene polymorphisms on the activities of CYPs with multiple genotypes. Methods: We genotyped 102 human livers for 18 known POR single nucleotide polymorphisms (SNPs) with allelic frequencies greater than 1% as well as for 27 known SNPs in 10 CYPs. CYP enzyme activities in microsomes prepared from these livers were determined by measuring probe substrate metabolism by high performance liquid chromatograph. Results: We found that the effects of the 18 POR SNPs on 10 CYP activities were CYP genotype-dependent. The POR mutations were significantly associated with decreased overall K_m for CYP2B6 and 2E1, and specific genotypes within CYP1A2, 2A6, 2B6, 2C8, 2D6 and 2E1 were identified as being affected by these POR SNPs. Notably, the effect of a specific POR mutation on the activity of a CYP genotype could not be predicted from other CYP genotypes of even the same CYP. When combining one POR SNP with other POR SNPs, a hitherto unrecognized effect of multiple-site POR gene polymorphisms (MSGP) on CYP activity was uncovered, which was not necessarily consistent with the effect of either single POR SNP. Conclusions: The effects of POR SNPs on CYP activities were not only CYP-dependent, but more importantly, CYP genotype-dependent. Moreover, the effect of a POR SNP alone and in combination with other POR SNPs (MSGP) was not always consistent, nor predictable. Understanding the impact of POR gene polymorphisms on drug metabolism necessitates knowing the complete SNP complement of POR and the genotype of the relevant CYPs.

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Section: Discussionmentioning

confidence: 99%

Effect of P450 Oxidoreductase Polymorphisms on the Metabolic Activities of Ten Cytochrome P450s Varied by Polymorphic CYP Genotypes in Human Liver Microsomes

Fang¹,

Gao²,

Tian³

et al. 2018

Cell Physiol Biochem

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“…, and CL -L were obtained by multiplying each individual liver weight (LW)/body weight (BW) by the individual tissue phenotype parameter, also known as Content -LT, V max-LT , and CL -LT, respectively. Detailed values of LW and BW were previously reported (Gao et al, 2017a). BW is the actual body weight for each individual, and LW is the liver weight, which is calculated by multiplying the liver volume (LV) by the liver density, wherein LV (ml) 5 12.5 Â BW (kg) 1 536.4 (Wang et al, 2008), and the liver density is 1.001 g/ml (Yuan et al, 2008).…”

Section: Determination Of Phenotype At Different Levelsmentioning

confidence: 99%

“…With regard to the characterization of CYP2A6 phenotypes, as mentioned in a previous study (Gao et al, 2017a), they can be divided into content phenotypes and metabolic phenotypes, as evidenced by CYP2A6 protein expression and activity from the molecular level to the cellular level and then to organismal level.…”

Section: Introductionmentioning

confidence: 99%

From Genotype to Phenotype: Content and Activities of Cytochromes P450 2A6 in Human Liver In Vitro and Predicted In Vivo

Fang

Wang

Guo

et al. 2019

J Pharmacol Exp Ther

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Unraveling the molecular mechanisms by which genetic variants of cytochrome P450 2A6 lead to different metabolic phenotypes remains a long-standing but important challenge. CYP2A6 is an enzyme involved in the metabolism of several clinical drugs as well as the metabolic activation of carcinogenic nitrosamines. Herein, CYP2A6 genotypes and phenotypes, as indicated by protein content [by liquid chromatography-mass spectrometry (MS)/MS] and metabolic activities [V max , clearance (CL)], were determined for 90 human liver samples. We determined the median, range, and interindividual and intraindividual variation of CYP2A6 content and activity at the microsomal, liver tissue, and whole liver level and predicted hepatic in vivo clearance by in vitro-in vivo extrapolation based on CYP2A6-mediated coumarin metabolism by each CYP2A6 genotype. These results reveal how different CYP2A6 genotypes yield different phenotypic traits in protein content and enzyme activity. For relative V max , CL, and protein content, the intraindividual percentage coefficients of variation (ICVs) were 41.0% (18.8%-125.1%), 28.5% (2.39%-133.5%), and 27.8% (2.68%-88.0%), respectively. The high ICVs implied large intraindividual variation at different levels, sometimes in a genotype-dependent manner. Intergenotype analysis revealed that the CYP2A6*4 allele demonstrated the most obvious effect on phenotypic outcomes, both in protein content and in metabolic activity. Indeed, decreased CYP2A6 protein content with the CYP2A6*4 genotype might explain the decreased metabolic activity from the molecular to the organismal level. These findings may allow useful predictions for CYP2A6-mediated drug metabolism on an individual patient basis in accord with the goal of achieving personalized medicine. SIGNIFICANCE STATEMENT We provide the median, range, and interindividual and intraindividual variation in CYP2A6 content at the microsomal, liver tissue, and whole liver level by liquid chromatography-mass spectrometry (MS)/MS as well as activities at the protein, microsomal, liver tissue, and whole liver level both in vitro and at the organismal level based on CYP2A6-mediated coumarin metabolism with each CYP2A6 genotype, thereby allowing us to elucidate how different CYP2A6 genotypes yield differing phenotypic traits (protein content and enzyme activity), facilitating the development of personalized medicine.

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“…UGT2B7 is considered to be polymorphic ( Coli c et al, 2015). We previously analyzed the effects of genetic polymorphisms on P450s (Gao et al, 2016b(Gao et al, , 2017a, but UGT2B7 has not been similarly characterized. In addition, UGT2B7 has the highest expression in liver, indicating that some liver-specific factors are needed for physiologic transcriptional responses (Yueh et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Content and Activities of UGT2B7 in Human Liver In Vitro and Predicted In Vivo: A Bottom-Up Approach

Gao

Zhang

et al. 2018

Drug Metab Dispos

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UDP-glucuronosyltransferase 2B7 (UGT2B7) is one of the most significant isoforms of UGTs in human liver. This research measured UGT2B7 protein content and activities, including maximum velocity (V) and intrinsic clearance (CL), in human liver at isoform, microsomal, liver tissue, and liver levels and identified the factors that influence expression. We determined absolute protein content by liquid chromatography-tandem mass spectroscopy and activities using the probe drug zidovudine in 82 normal human liver microsomes. Using a bottom-up method for derivation, we showed UGT2B7 content at the microsomal, liver tissue, and liver levels, as well as activities at the isoform, microsomal, liver tissue, and liver levels in vitro, and predicted hepatic clearance in vivo, with median, range, variation, and 95% and 50% prediction intervals. With regard to the intrinsic activities, the maximum velocity (V) had a median (range) of 7.5 (2-24) pmol/min per picomole of 2B7, and the CL was 0.08 (0.02-0.31) l/min per picomole of 2B7. Determinations at liver level showed larger variations than at microsomal level, so it was more suitable for evaluating individual differences. By analyzing factors that affect UGT2B7, we found that: 1) The content at the liver tissue and liver levels correlated positively with activities; 2) the mutant heterozygotes of, , may lead to decreased protein content and increased intrinsic CL; and 3) the transcription factor pregnane X receptor mRNA expression level was positively associated with the measured protein content. In all, we showed that protein content and activities at different levels and the factors that influence content provide valuable information for UGT2B7 research and clinically individualized medication.

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From Genotype to Phenotype: Cytochrome P450 2D6-Mediated Drug Clearance in Humans

Cited by 13 publications

References 58 publications

Effect of P450 Oxidoreductase Polymorphisms on the Metabolic Activities of Ten Cytochrome P450s Varied by Polymorphic CYP Genotypes in Human Liver Microsomes

Effect of P450 Oxidoreductase Polymorphisms on the Metabolic Activities of Ten Cytochrome P450s Varied by Polymorphic CYP Genotypes in Human Liver Microsomes

From Genotype to Phenotype: Content and Activities of Cytochromes P450 2A6 in Human Liver In Vitro and Predicted In Vivo

Content and Activities of UGT2B7 in Human Liver In Vitro and Predicted In Vivo: A Bottom-Up Approach

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