CYP450氧化还原酶的遗传多态对药物代谢的影响

CYP450氧化还原酶(cytochrome P450 oxidoreductase,POR)是所有肝微粒体的细胞色素P450氧化酶(cytochrome P450 monooxygenases,CYP)的唯一电子供体,其中一些CYP是I相药物代谢酶,负责临床上超过80%药物的氧化代谢。另外,POR直接介导了一些抗肿瘤前体药物的代谢。因此,POR的遗传多态引起其活性的改变,对临床药物代谢具有非常重要的临床意义。该文总结了近年来POR的遗传多态影响药物代谢的最新研究进展。     

CYP450氧化还原酶遗传多态性对CYP酶影响的研究进展

细胞色素P450氧化还原酶(Cytochrome P450 0xidoreductase,POR)是将电子从NADPH转运至所有肝微粒体的细胞色素P450氧化酶(Cytochrome P450 monooxygenases,CYP)中的唯一供体.药物、类固醇激素等物质的代谢和转化需要CYP参与.POR基因具有遗传多态性,遗传变异可以改变CYP活性,引起P450氧化还原酶缺陷(P450 0xidoreductase deficiency,PORD)、临床药物代谢和反应差异.本文将从POR的结构功能、基因突变引起的疾病及其对酶活性影响三个方面进行论述,总结近年来POR遗传多态性对CYP酶影响的最新研究进展.     

CYP450氧化还原酶基因多态性的临床研究进展

CYP450氧化还原酶（POR）是所有肝微粒体的细胞色素P450氧化酶（CYP450）的唯一电子供体,负责甾醇激素、胆固醇、胆酸、维生素以及临床上超过80％药物的氧化代谢。POR本身具有高度的多态性,国内外报道显示POR基因的突变可使其本身活性或它与CYP450酶之间的相互作用发生改变,致使它与临床某些疾病的发生及某些药物体内代谢活性的改变密切相关。而POR基因多态性与CYP介导的药物代谢之间存在着CYP酶种类及底物的特异性,且国内相关研究相对较少。因此,我们通过对近年来POR基因多态性的临床研究进展进行综述,为今后相关研究及临床药物的个体化治疗提供参考。     

细胞色素P450基因多态性与药物代谢研究进展

细胞色素P450酶(cytochrome P450,CYP450)是参与人类药物代谢过程的重要酶,在肝细胞和小肠上皮细胞的光滑内质网中含量丰富,其主要功能是氧化还原各种内源性物质和外源性物质。CYP450酶参与80%目前应用药物的I相代谢,参与各种激素合成,影响与激素相关的肿瘤疾病发展。CYP450基因和表型存在高度多态性,体现在个体对于各种物质的代谢存在明显差异。本文综述了CYP450的基因多态性、与药物代谢相关的CYP450各亚型特点和临床意义,对发展以指导个体化用药为基础的精准医学具有重要意义。     

细胞色素P450 氧化还原酶缺陷症研究进展

细胞色素P450氧化还原酶缺陷症(cytochrome P450 oxidoreductase deficiency,PORD)是一种较罕见的常染色体隐性遗传病,典型表现包括类固醇合成异常、两性畸形及Antley-Bixler综合征(Antley-Bixler syndrome,ABS)样骨骼畸形等[1-4]。细胞色素P450氧化还原酶(cytochrome P450 oxidoreductase,POR)可作为细胞色素P450酶(cytochrome P450,CYP)的电子转运体,参与类固醇激素的合成等[2-3]。PORD可导致性激素和糖皮质激素合成障碍,因此它属于先天性肾上腺皮质增生症(congenital adrenal hyperplasia,CAH)的一种亚型[1-3]。Flück C E等[1]于2004年首次描述了PORD病例,至今已报道了140余例。本文汇总了常见POR基因突变类型、体外功能研究及临床病例,并从分子水平到疾病诊疗等方面介绍PORD的研究进展。     

Cocktail法研究CYP450酶活性影响因素的探讨

细胞色素P450酶(cytochrome P450, CYP450)是药物代谢的重要酶系,研究CYP450对阐明药物代谢通路、相互作用、代谢多态性、指导临床合理用药等方面具有重要意义.混合探针底物法(Cocktail法)在研究CYP450亚型酶活性应用广泛,具有高效、准确、灵敏、高通量的特点.但CYP450亚型酶存在种属差异、性别差异、探针药物的特异性等方面的问题.查阅国内外相关文献,探讨Cocktail法研究CYP450酶活性的影响因素.     

细胞色素P450酶参与动物体内代谢的研究与展望

细胞色素P450酶(Cytochrome P450 enzymes,CYP450)通过其活性部位的Fe3+使底物得到O2 中的一个氧原子并伴随着得失电子来进一步实现化合物的氧化过程.其家族成员CYP3A4 在治疗抗COVID-19 的化学药物中能介导利托那韦(Ritonvir)与洛匹那韦(Lopinavir)的代谢来达...     

细胞色素P450的基因多态性与药物代谢

细胞色素P450（cytochrome P450，CYP）是重要的药物代谢酶，参与催化多种内源和外源化合物，特别是多种临床药物的生物转化。CYP存在广泛的基因多态性和表型多态性，使其对于各种化合物的代谢存在统计学个体差异。核受体是配体依赖性转录因子超家族，与药物代谢过程中的基因表达调控密切相关，被外源物质活化后诱导或抑制CYP基因的表达。现综述CYP与药物代谢、CYP的基因多态性、CYP表达的诱导机制、核受体及其配体诱导CYP表达及近年研究CYP450的各种实验方法。     

细胞色素P450酶基因多态性的研究进展及临床意义

细胞色素P450（cytochrome P450,CYP）是重要的药物代谢酶,参与催化多种内源和外源化合物,特别是多种临床药物的生物转化。CYP存在广泛的基因多态性和表型多态性,体现在个体对于各种化合物的代谢存在明显差异。本文综述了CYP的基因多态性、与药物代谢相关的CYP各亚型的特点和临床意义,主要目的是合理解释和预测临床上药物间相互作用和药物不良反应等,为实现临床个体化给药提供科学依据。     

CYP2A6多态性对尼古丁代谢及烟草依赖行为的影响

细胞色素P450(cytochrome P450,CYP)超基因家族是人体内最重要的药物代谢酶,其中的一些亚型所具有的基因多态性表现出人体对药物和/或环境化合物毒性、敏感性存在差异,CYP2A6为其一例。     

Altered hepatic drug-metabolizing activity in rats suffering from hypoxemia with experimentally induced acute lung impairment

1.?Hepatic drug-metabolizing activity was investigated in vitro with liver microsomes prepared from rats suffering from hypoxemia with experimentally induced acute lung impairment (ALI).

2.?Male Wistar rats received an intrabronchial administration of dilute hydrochloride solution for ALI induction. Pooled liver microsomes were prepared for the normal and ALI rats, and the hepatic drug metabolism mediated by cytochrome P450 (CYP) 3?A was examined in an incubation study with the microsomes.

3.?The NADPH-dependent metabolism of midazolam significantly increases in ALI rats as compared with that in normal rats. Testosterone 6β-hydroxylation was also observed to significantly increase in ALI rats.

4.?When the hepatic expression of CYP3A proteins was examined, the protein expression of CYP3A1 was shown to significantly increase and that of CYP3A2 remained unaltered in ALI rats. The hepatic expression of NADPH-cytochrome P450 reductase (POR), a protein mediating electron transfer in CYP-mediated drug metabolism, was also revealed to significantly increases in ALI rats.

5.?With the findings regarding the midazolam elimination, the hepatic drug-metabolizing activity seems to increase in response to acute hypoxemia, partly due to an altered expression of the CYP3A enzymes, and an augmented electron transfer with an increased POR expression is probably involved in the increase.     

细胞色素P450活性与癌症治疗

本文通过总结影响细胞色素P450活性的因素和抗肿瘤药的生物转化途径,以期探索细胞色素P450同工酶介导的代谢在抗癌药物体内生物转化中的作用,进而探索该酶活性与癌症患者的疗效之间的相关性。发现化疗药物的个体间药代动力学差异会引起治疗的疗效和安全性的不同结果。年龄、性别、单个基因多态性等单一因素并不能阐明个体间对药物反应的差异性,化疗方案中多个药物的相互作用在临床上非常重要。为了更好地评估细胞色素P450酶类对机体代谢的作用,药物的吸收、排泄、活化,以及代谢整个药代动力学途径涉及的酶的多态性都应进行研究。     

细胞色素P450和医学

细胞色素P450(CYP,P450)是一个血红蛋白家族的通用名称.这是一个非常巨大、种类丰富的酶家族,广泛存在于进化谱系所有生物体中(从细菌到人).已经发现和命名的不同CYP蛋白超过11500个(截止至2009年2月),但只有少数进行了详细研究.该家族参与到生命进程中众多的新陈代谢反应,包括羟基化、N-,O-,和S-脱烷基化、磺化氧化、环氧化、脱氨、脱硫、脱卤、过氧化和N-氧化还原作用.本文介绍了细胞色素P450的研究历史、结构、命名法、分类及功能.人类和动物细胞色素P450酶类与诸多疾病相关,尤其是肝病和癌症.三个细胞色素P450基因家族(CYP 1,CYP2和CYP3)似乎参与大量抗生素代谢反应.人们正在深入研究CYP450的功能,为不久的将来能战胜肝病、癌症和其他疾病提供可能性.     

Metabolism of CJ-036878, N-(3-phenethoxybenzyl)-4-hydroxybenzamide,in liver microsomes and recombinant cytochrome P450 enzymes: metabolite identification by LC-UV/MSn and 1H-NMR

The identification of metabolites in the early stages of drug discovery is important not only for guiding structure–activity relationships (SAR) and structure–metabolism relationships (SMR) strategies, but also for predicting the potential for adverse events. The present study investigated the phase I metabolism of CJ-036878 (N-(3-phenethoxybenzyl)-4-hydroxybenzamide), a potent antagonist of the N-methyl-D-asparatate (NMDA) receptor, using liver microsomes and representative recombinant cytochrome P450 enzymes. The structures of the oxidative metabolites M1–M11 were confirmed by LC-UV/MSⁿ and/or ¹H-nuclear magnetic resonance (NMR). It was found that CJ-036878 is metabolized through three routes: (1) aliphatic hydroxylation that generates M1 and M2; (2) aromatic hydroxylation that produces M3–M5, M7 and M8; and (3) dimerization through an oxidative phenol coupling reaction that yields M10 and M11. The use of recombinant human cytochrome P450 enzymes suggested that CYP3A4 is the major enzyme involved in the oxidative metabolism of CJ-036878, with minor contributions from CYP1A2, CYP2C19, and CYP2D6.     

P450 oxidoreductase: genetic polymorphisms and implications for drug metabolism and toxicity

BACKGROUND: Cytochrome P450 oxidoreductase (POR) is the only electron donor for all microsomal cytochrome P450 monooxygenases (CYP), some of which are phase I drug-metabolizing enzymes, responsible for oxidation of more than 80% of drugs. OBJECTIVES: To provide a more thorough understanding of the genetic factors influencing drug metabolism, we address the role of genetic polymorphisms in the POR gene, and their implications for drug metabolism and cytotoxicity. METHODS: The scope of this review is intended to cover polymorphisms currently identified in the POR gene, assess their functional significance on POR activity, and address their impact on CYP-mediated drug metabolism. POR is also responsible for directly metabolizing several anticancer prodrugs via a 1-electron reduction reaction, so the effect of POR polymorphisms on the direct bioactivation of drugs is also considered. RESULTS/CONCLUSION: POR is a polymorphic enzyme that can affect CYP-mediated drug metabolism as well as direct bioactivation of prodrugs. Genetic polymorphisms in the POR gene may help to explain altered drug-metabolizing phenotypes.     

Pharmacogenetics of P450 oxidoreductase: effect of sequence variants on activities of CYP1A2 and CYP2C19

OBJECTIVES: All microsomal cytochrome P450s enzymes, including those that metabolize the majority of clinically used drugs, require electron transfer through P450 oxidoreductase (POR). Mutations in human POR cause altered steroidogenesis and congenital malformations, but the clinical effects on drug metabolism are unclear. We examined the effects of POR sequence variants on two drug-metabolizing P450 enzymes, CYP1A2 and CYP2C19. METHODS: Our previous sequencing of the human POR gene in POR-deficient patients and in 842 normal individuals identified 35 sequence variants. We expressed these 35 POR sequence variants in bacteria, reconstituted them with the CYP enzymes in vitro, and assayed their activities with human CYP1A2 and CYP2C19. RESULTS: POR variants affected the activities of these enzymes to different extents. Disease-causing POR mutations A287P and R457H diminished catalysis by CYP1A2 and CYP2C19 to barely detectable levels. POR A503V, a polymorphism found in 28% of alleles in the normal population, had 85% of wild-type activity with CYP1A2 and 113% of wild-type activity with CYP2C19. Q153R, a disease-causing mutation that severely impaired steroidogenic activity and cytochrome c reduction, increased the activity of CYP1A2 to 144% and CYP2C19 activity to 284% of control. CONCLUSION: The activity of individual POR mutants may vary greatly depending on the electron recipient used to assay activity. Thus, the activity of a POR mutant to support catalysis by a particular P450 enzyme cannot be predicted by the activity of that POR mutant in an assay with a different P450 or with cytochrome c.     

Cytochrome P450 reductase dependent inhibition of cytochrome P450 2B1 activity: Implications for gene directed enzyme prodrug therapy

Cytochrome P450 (P450) enzymes are often used in suicide gene cancer therapy strategies to convert an inactive prodrug into its therapeutic active metabolites. However, P450 activity is dependent on electrons supplied by cytochrome P450 reductase (CPR). Since endogenous CPR activity may not be sufficient for optimal P450 activity, the overexpression of additional CPR has been considered to be a valuable approach in gene directed enzyme prodrug therapy (GDEPT). We have analysed a set of cell lines for the effects of CPR on cytochrome P450 isoform 2B1 (CYP2B1) activity. CPR transfected human embryonic kidney 293 (HEK293) cells showed both strong CPR expression in Western blot analysis and 30-fold higher activity in cytochrome c assays as compared to parental HEK293 cells. In contrast, resorufin and 4-hydroxy-ifosfamide assays revealed that CYP2B1 activity was up to 10-fold reduced in CPR/CYP2B1 cotransfected HEK293 cells as compared to cells transfected with the CYP2B1 expression plasmid alone. Determination of ifosfamide-mediated effects on cell viability allowed independent confirmation of the reduction in CYP2B1 activity upon CPR coexpression. Inhibition of CYP2B1 activity by CPR was also observed in CYP2B1/CPR transfected or infected pancreatic tumour cell lines Panc-1 and Pan02, the human breast tumour cell line T47D and the murine embryo fibroblast cell line NIH3T3. A CPR mediated increase in CYP2B1 activity was only observed in the human breast tumour cell line Hs578T. Thus, our data reveal an effect of CPR on CYP2B1 activity dependent on the cell type used and therefore demand a careful evaluation of the therapeutic benefit of combining cytochrome P450 and CPR in respective in vivo models in each individual target tissue to be treated.     

Inhibition of Cytochrome P450 Enzymes by Drugs—Molecular Basis and Practical Applications

Drug-drug interactions are a major cause of hospitalization and deaths related to drug use. A large fraction of these is due to inhibition of enzymes involved in drug metabolism and transport, particularly cytochrome P450 (P450) enzymes. Understanding basic mechanisms of enzyme inhibition is important, particularly in terms of reversibility and the use of the appropriate parameters. In addition to drug-drug interactions, issues have involved interactions of drugs with foods and natural products related to P450 enzymes. Predicting drug-drug interactions is a major effort in drug development in the pharmaceutical industry and regulatory agencies. With appropriate in vitro experiments, it is possible to stratify clinical drug-drug interaction studies. A better understanding of drug interactions and training of physicians and pharmacists has developed. Finally, some P450s have been the targets of drugs in some cancers and other disease states.