尿苷二磷酸葡醛酸转移酶的研究进展

尿苷二磷酸葡醛酸转移酶(UGT)是体内最重要的Ⅱ相代谢酶,它可以参与许多内源性物质如胆红素、甾体激素、甲状腺激素、胆汁酸和脂溶性维生素等的代谢,在许多药物如阿片类药物、镇痛药、非甾体抗炎药和抗惊厥药等的代谢中也发挥着重要的作用。UGT在药物的吸收、分布、代谢和排泄中发挥重要作用。研究UGT特别是其基因多态性及其介导的药物-药物相互作用不仅可以指导临床用药,也可以揭示内源性物质代谢紊乱的机制。本文就UGT的分类、组织分布、对药物吸收的影响、基因多态性及其所介导的药物-药物相互作用进行综述。     

尿苷二磷酸葡萄糖醛酸转移酶的研究进展

目的:介绍尿苷二磷酸葡萄糖醛酸转移酶(UGT)的最近研究进展;方法:查阅了大量相关文献,总结了UGT的功能、诱导、底物及其基因研究等内容;结果:UGT是一种最重要的Ⅱ相代谢酶,对它的研究已经深入到基因水平,且可从分子水平上去解释它的作用机理;结论:人们对UGT有了更深更全面的了解。     

尿苷二磷酸葡萄糖醛酸转移酶的研究进展

目的：介绍尿苷二磷酸葡萄糖醛酸转移酶（UGT）的最近研究进展;方法：查阅了大量相关文献,总结了UGT的功能、诱导、底物及其基因研究等内容;结果：UGT是一种最重要的Ⅱ相代谢酶,对它的研究已经深入到基因水平,且可从分子水平上去解释它的作用机理;结论：人们对UGT有了更深更全面的了解。     

尿苷二磷酸葡醛酸转移酶介导的胆汁酸代谢过程及其内源和外源影响因素研究进展

尿苷二磷酸葡萄糖醛酸转移酶(UDP-glucuronosyltransferases, UGTs)作为人体中一种非常重要的II相代谢酶,不仅参与外源性化合物代谢清除,也在胆汁酸等内源性物质的代谢调控中扮演重要角色。解析尿苷二磷酸葡萄糖醛酸转移酶介导的胆汁酸代谢过程及其内源和外源影响因素有助于增强对相关疾病的治疗和预防。尿苷二磷酸葡萄糖醛酸转移酶对胆汁酸代谢调控作用受到多种内源性和外源性因素影响。本文将重点探讨核受体、遗传因素、外源化合物及肝脏相关疾病等因素对UGT酶作用的影响,讨论体内潜在的胆汁酸动态平衡干预机制。     

尿苷二磷酸葡萄糖醛酸转移酶基因多态性对药物代谢影响的研究进展

由尿苷二磷酸葡萄糖醛酸转移酶(UDP-glucuronosyltransferase,UGT)催化完成的葡萄糖醛酸结合反应是生物体内重要的Ⅱ相代谢途径,它与毒性或活性物质结合形成葡萄糖醛酸苷,将内源性、外源性化合物通过胆汁或肾脏排出体外。UGT是一个超家族酶,因主要利用UDP-尿苷二磷酸葡糖醛酸为糖基供体而得名。人类UCT广泛分布于体内的各种组织,包括肾、脑、皮肤、肠、脾、胸腺、心脏等,其中以     

尿苷二磷酸葡萄糖醛酸转移酶与内源性物质的相互作用

尿苷二磷酸葡萄糖醛酸转移酶(UGT)是人体重要的II相代谢酶,代谢药物的同时也代谢许多重要的内源性物质,如胆红素、甲状腺激素、雌激素、雄激素、胆汁酸和5-羟色胺等。该酶对许多内源性物质的代谢是灭活和清除这些内源性物质的关键步骤,能够防止内源性物质累积引发的毒性反应,或及时终止内源性激素的信号防止肿瘤的发生。然而,内源性物质对UGT酶也会产生影响,特别是在一些生理病理条件下,某些内源性物质能够抑制UGT酶活性,影响其参与的代谢反应。将就内源性物质和UGT酶的相互作用做一综述,以引起人们对UGT酶和内源性物质相互作用的关注。关键词:药物代谢;尿苷二磷酸葡萄糖醛酸转移酶;内源性物质     

腺苷蛋氨酸对L02细胞尿苷二磷酸葡萄糖醛酸转移酶表达的影响

目的 探讨腺苷蛋氯酸( S-adenosyl-L-methionine,SAMe)对尿苷二磷酸葡萄糖醛酸转移酶(Uridine Diphosphate Glucuronsyltransferase,UGT)表达的调节作用.方法 体外培养102细胞加入药物分别处理0～72 h后应用RT-PCR法观察SAMe对UGT mRNA的作用.结果 0.5 mmol/L的SAMe在24～ 72 h可上调UGTmRNA的表达,0.1～l mmol/L的SAMe都能上调UGTmRNA的表达,但0.5mmol/L的作用最强,强于苯巴比妥.结论 SAMe可以上调UGTmRNA的表达,从而促进胆红素代谢.     

人尿苷二磷酸葡萄糖醛酸转移酶基因多态性与相关疾病易感性

尿苷二磷酸葡萄糖醛酸转移酶(UGT)是体内重要的药物代谢Ⅱ相酶,具有明显的基因多态性。评价基因多态性对疾病易感性影响的重要性,建立基因多态性数据库并进行致病基因-疾病易感性的种群研究具有深远意义。本文拟就人UGT基因多态性及相关疾病易感性进行简述。     

尿苷二磷酸葡萄糖醛酸转移酶的转录调节与疾病相关性的研究进展

葡萄糖醛酸结合反应是体内重要的Ⅱ相代谢途径,主要由尿苷二磷酸葡萄糖醛酸转移酶（ UGT ）催化。尿苷二磷酸葡萄糖醛酸转移酶能参与多种内源性物质如胆红素、胆汁酸、甲状腺激素等的代谢,也能参与多种药物如阿片类镇痛药、非甾体抗炎药等药物的代谢,在代谢解毒方面起着重要作用。近年来对尿苷二磷酸葡萄糖醛酸转移酶的研究越来越深入,尿苷二磷酸葡萄糖醛酸转移酶与不同疾病的研究受到普遍关注。本文就转录因子介导的尿苷二磷酸葡萄糖醛酸转移酶的分子调节机制及其与不同疾病的相关性研究进行综述。     

尿苷二磷酸葡醛酸转移酶介导的酪氨酸激酶抑制剂药物相互作用研究进展

近年来由代谢酶和转运体介导的酪氨酸激酶抑制剂(TKIs)的药物相互作用(DDI)已成为临床治疗的一个重要问题。除CYP450酶,尿苷二磷酸葡醛酸转移酶(UGTs)是参与TKIs代谢的另一类代谢酶,而且在体外多数TKI对UGTs呈抑制作用。TKIs与UGTs底物或抑制剂联合用药可能发生潜在的有临床意义的DDI。本文将重点研究UGTs介导的TKIs的药物-药物相互作用以及UGT1A基因型对TKIs的药物相互作用的影响,并探讨解决策略,以期为临床医师和药师对TKIs的安全合理应用提供参考。     

人尿苷二磷酸葡醛酸转移酶1A6重组酶对酚类和羧酸类化合物与葡醛酸结合的催化活性

目的利用杆状病毒系统表达的人尿苷二磷酸葡醛酸转移酶(UGT)1A6重组酶对一些化合物进行葡醛酸结合研究,以筛选或验证UGT1A6重组酶的底物。方法采用HPLC法对底物或代谢物进行检测,并根据底物的减少来计算该酶对各底物的酶动力学参数。结果人UGT1A6重组酶能很好地催化α-萘酚、β-萘酚和儿茶酚的葡醛酸结合,但对托特罗定、对乙酰氨基酚、水杨酸、对氨基水杨酸、槲皮素、山奈酚、异鼠李素、扁桃酸、布洛芬和萘普生无明显催化活性。结论人UGT1A6重组酶对平面的简单酚类化合物有明显的催化活性,但对结构复杂的酚类或羧酸类化合物活性不明显。     

Effect of Uridine Diphosphoglucose on Levels of 5-Phosphoribosyl Pyrophosphate and Uridine Triphosphate in Murine Tissues

The purpose of the present investigation was to determine whether a single bolus intravenous injection (2000 mg/kg) of uridine diphosphoglucose (UDPG) could affect levels of PRPP in a transplanted mammary adenocarcinoma and in liver of CD8FI mice. Six hours following a single intravenous injection of UDPG, 2000 mg/kg, tumor PRPP was lowered to 80 pmol/mg protein, a 53% decrease compared to saline control tumors. Liver was more sensitive than tumor to the 5-phosphoribosyl pyrophosphate (PRPP)-depleting effects of a single bolus intravenous injection of UDPG, since significantly lower levels of PRPP were found in liver, but not in tumor, at doses of 500–1000 mg/kg of UDPG. Maximal depression (30% of saline control) or PRPP occurred in liver 6 hr after intravenous UDPG at 1000–2000 mg/kg. Enhanced levels of UDPG in plasma (half-life less than 10 min) and tumor was detected at 30 min after intravenous UDPG at 2000 mg/kg. There was no detectable increase in endogenous levels of UDPG in liver at this time, probably as a result of rapid metabolism of UDPG by liver. At this same time, a twofold increase in uridine triphosphate (UTP) was measured in liver after intravenously administered UDPG. In contrast, the level of UTP was not increased significantly above control values in tumor. These data suggest the potential use of UDPG to elevate UTP pools in normal tissues in the delayed rescue of cancer chemotherapeutic drugs such as 5-fluorouracil which function as a uridine analogue in these tissues.     

Uridine diphosphate glucose dehydrogenase of calf liver. Properties and inhibition characteristics with uridine diphosphate xylose analogues

UDP-glucose dehydrogenase of calf liver dissociated in guanidine-HCl into six subunits. The number of reactive sulfhydrylgroups of native and guanidine-HCl-treated enzyme was found to be 20 ± 1 and 46 ± 1, respectively, per mole of native enzyme. A crude preparation of UDP-glucose pyrophosphorylase from yeast was used for the preparation of 5-hydroxyuridine diphosphate xylose and 5-aminouridine diphosphate xylose. 5,6-Dihydrouridine diphosphate xylose was prepared by catalytic reduction of UDP-xylose. The nature of the inhibition produced by UDP-xylose or its analogues was similar with respect to either UDP-glucose or NAD⁺, the two substrates for the enzyme. Hydrogenation of the 5,6-double bond or substitution of a hydroxyl group at the C-5 position of the pyrimidine portion of UDP-xylose decreased its inhibitory activity. Substitution of an amino group at the C-5 position, however, did not alter the activity of the allosteric inhibitor.     

Early‐Onset 5‐Fluorouracil Toxicity in a Patient Negative for Dihydropyrimidine Dehydrogenase Mutations: The Clinical Course of Reversal with Uridine Triacetate

An antimetabolite pyridine analog, 5‐fluorouracil (5‐FU), is used to treat solid tumors. Early toxicities may occur at standard doses of 5‐FU due to dihydropyrimidine dehydrogenase (DPD) deficiency. Uridine triacetate, approved by the Food and Drug Administration in 2015, is an oral prodrug of uridine, a pharmacologic antidote for 5‐FU toxicity. To our knowledge, this is the first case report that documents the clinical course of a patient treated with uridine triacetate to reverse early‐onset 5‐FU toxicity negative for DPD mutations. We describe the case of a 73‐year‐old man with anal cancer treated with standard‐of‐care chemotherapy and radiation. Two days after completion of his initial 5‐FU infusion, the patient developed severe mucositis and extreme fatigue, followed by a rapid decline in his blood cell counts and fevers. The patient was initiated on uridine triacetate 86 hours after completion of his 5‐FU infusion. Over a 10‐day hospital length of stay, the patient's absolute neutrophil count recovered to within normal limits, and his mucositis significantly improved. At follow‐up visits, the patient denied any residual symptoms of 5‐FU toxicity. We describe the patient's clinical course from hospital presentation to 31 days after initiation of uridine triacetate.     

Effect of de novo purine synthesis inhibitors on 5-fluorouracil metabolism and cytotoxicity

Methotrexate pretreatment of L1210 cells had been shown previously by us to cause an enhancement of the intracellular accumulation of 5-fluorouracil and of the formation of 5-fluorouracil nucleotides which was correlated with synergistic cytotoxicity. This effect of methotrexate was associated with increases in 5-phosphoribosyl-1-pyrophosphate, the cofactor required for the conversion of 5-fluorouracil to 5-fluorouridine-5'-monophosphate (FUMP). Because these influences on 5-fluorouracil metabolism were most likely mediated by the activity of methotrexate as an inhibitor of purine synthesis, the effects of other agents that inhibit purine synthesis were examined. An inhibitor of amidophosphoribosyltransferase, 6-methylmercaptopurine ribonucleoside, the glutamine antagonists, azaserine and 6-diazo-5-oxo-L-norleucine (DON), and the L-aspartate analogue inhibitor of adenylsuccinate synthetase, L-alanosine, all reduced the incorporation of [1-14C]glycine into adenine and guanine bases isolated from nucleic acids. Each drug also resulted in intracellular elevations of 5-phosphoribosyl-1-pyrophosphate that were 15- to 25-fold greater than control levels. These alterations in de novo purine nucleotide synthesis were associated with enhanced intracellular 5-fluorouracil accumulation and synergistic cytotoxicity.     

Schedule-dependency of in vivo modulation of 5-fluorouracil by leucovorin and uridine in murine colon carcinoma

Summary The effect of leucovorin (LV) given in various doses and schedules on the in vivo antitumor activity and toxicity of 5-fluorouracil (5FU) was studied in two murine colon cancer lines, i.e., Colon 26 (relatively resistant to 5FU) and Colon 38 (5FU sensitive), maintained in Balb-c and C57B1/6 mice, respectively. Mice were treated weekly with 5FU at the maximum tolerated dose, alone and in combination with LV. In Colon 26, neither simultaneous administration of 5FU and LV nor 5FU combined with delayed administration of LV potentiated the antitumor activity of 5FU. LV given twice — 1 hr before (50 mg/kg) and then together (50 mg/kg) with 5FU (100 mg/kg) — gave significantly better delay of tumor growth of both tumor lines than 5FU did alone (100 mg/kg). No differences were found after a total LV dose of 100 or 200 mg/kg. Delayed administration of uridine (3500 mg/kg) allowed the use of higher 5FU doses, which improved the antitumor effect on Colon 26. Systemic toxicity led to moderate weight loss in treated mice, but was comparable for mice treated with 5FU alone or combined with LV. Hematological toxicity consisted of moderate leukopenia (nadir 40%), which was observed with the most active schedule and was less severe than with 5FU alone. This schedule did not cause thrombocytopenia, but after discontinuation the thrombocyte count showed an overshoot. Addition of uridine to this schedule reduced hematological toxicity only slightly. It is concluded that LV potentiated the antitumor activity of 5FU against two solid tumor lines, i.e., a relatively resistant and a sensitive murine colon carcinoma, and that toxicity was moderate.Abbreviations 5FU 5-fluorouracil - LV leucovorin (folinic acid, 5-formyl-tetrahydrofolate) - FdUMP 5-fluoro 2-deoxyuridine 5monophosphate - TS thymidylate synthase - CH2-THF 5-10 methylenetetrahydrofolate - UR uridine - GDF growth delay factor - TD tumor doubling time - MTD maximum tolerated dose - T/C mean tumor volume of treated mice divided by mean tumor volume of control mice     

Characterizing the effect of UDP-glucuronosyltransferase (UGT) 2B7 and UGT1A9 genetic polymorphisms on enantioselective glucuronidation of flurbiprofen

Flurbiprofen (FPF), available commercially as a racemic mixture, is a propionic acid derivative of non-steroidal anti-inflammatory drugs (NSAIDs) with known stereoselective glucuronidation. The major enzyme catalyzing this conjugation reaction is UDP-glucuronosyltransferase (UGT) 2B7, with minor contributions by UGT1A9. This study examines the role of the genetic variants of UGT2B7 and 1A9 enzymes involved in the formation of acyl glucuronides (FPFGs). Variants caused by three single nucleotide polymorphisms (SNPs) (A71S, 211G>T; H268Y, 802C>T; and D398N, 1192G>A) in UGT2B7 and three SNPs (C3Y, 8G>A; M33T, 98T>C; D256N, 766G>A) in UGT1A9 showed activity changes toward different substrates. However the functional impacts of these SNPs on chiral substrates were not examined. Upon stable expression in Bac-to-Bac system, UGT2B7*71S (A⁷¹S), UGT2B7*2 (H²⁶⁸Y) and UGT2B7*5 (D³⁹⁸N) were all associated with a decrease in the formation of FPFGs. Compared with UGT2B7*1 (wild-type), UGT2B7*71S exhibited a >2-fold lower intrinsic clearance mainly by altered capacities (V_max). Furthermore, a >14-fold decreased intrinsic clearance of the *1 protein was produced by UGT2B7*2 and UGT2B7*5. However, no significantly stereoselective difference for the formation of (R)- and (S)-FPFG was found among these UGT2B7 allozymes. UGT1A9*2 (C³Y) exhibited a higher V_max (3.2-fold), K_m (2.1-fold) and intrinsic clearance (1.6-fold) toward (S)-FPF than UGT1A9*1 (wild-type). UGT1A9*3 (M³³T) almost lost the catalytic activity to FPF. A significantly stereoselective difference on the glucuronidation of rac-FPF was seen between the two variants compared with the wild type of UGT1A9.     

Identification of human cytochrome P450 enzymes involved in the metabolism of IN-1130, a novel activin receptor-like kinase-5 (ALK5) inhibitor

1.?The in vitro metabolism of 3-((5-(6-methylpyridin-2-yl)-4-(quinoxalin-6-yl)-1H-imidazol-2-yl)methyl)benzamide (IN-1130), a selective activin receptor-like kinase-5 (ALK5) inhibitor and a candidate drug for fibrotic disease, was studied.

2.?The cytochrome P450s (CYPs) responsible for metabolism of IN-1130 in liver microsomes of rat, mouse, dog, monkey and human, and in human CYP supersomes?, were identified using specific CYP inhibitors. The order of disappearance of IN-1130 in various liver microsomal systems studied was as follows: monkey, mouse, rat, human, and dog.

3.?Five distinct metabolites (M1–M5) were identified in all the above microsomes and their production was substantially inhibited by CYP inhibitors such as SKF-525A and ketoconazole. Among nine human CYP supersomes? examined, CYP3A4, CYP2C8, CYP2D6*1, and CYP2C19 were involved in the metabolism of IN-1130, and the production of metabolites were significantly inhibited by specific CYP inhibitors. IN-1130 disappeared fastest in CYP2C8 supersomes. CYP3A4 produced four metabolites of IN-1130 (M1–M4), whereas supersomes expressing human FMO cDNAs, such as FMO1, FMO3, and FMO5, produced no metabolites.

4.?Hence, it is concluded that metabolism of IN-1130 is mediated by CYP3A4, CYP2C8, CYP2D6*1, and CYP2C19.     

CXCL5表达强度与不同类型乳腺癌关系

目的 本研究探讨CXCL5与乳腺癌恶性度的关系,观察与临床分期、病情进展的意义.方法 免疫组化(SABC法)确定乳腺癌CXCL5表达的水平.结果 病理Ⅲ+IV期CXCL5表达阳性率显著增高,与病理I+II期比较差异显著(P<0.01).发生淋巴结转移的病例CXCL5表达增高,与未发生转移病例比较具有显著性(P<0.01);比较不同组织类型乳腺癌表达CXCL5的差异,可发现乳腺癌组明显高于纤维腺瘤组,具有显著性(P<0.01).结论 CXCL5是乳腺癌发生、发展过程中的重要成分,与乳腺癌的新生血管形成、基因调节通路以及乳腺癌的转移密切相关.