ABCB1基因C3435T多态性与耐药性癫痫的关系

目的:探讨中国粤西地区汉族人群ABCB1基因C3435T (rs1045642)的单核苷酸多态性与耐药性癫痫的关系.方法:研究对象128例,包括正常对照组60例和癫痫组68例.根据患者对抗癫痫药物的反应性将癫痫组分为耐药组(30例)和药物敏感组(38例).提取所有研究对象外周血基因组DNA,采用PCR扩增后基因测序鉴定ABCB1基因C3435T多态性.测定该位点基因型频率和等位基因频率,并进行统计学分析.结果:各组ABCB1基因C3435T基因型频率的分布符合Hardy-Weinburg平衡,提示其来自同一孟德尔群体.正常对照组与药物敏感组及耐药组,药物敏感组与耐药组间基因型频率比较,差异均无统计学意义(P＞0.05).正常对照组与药物敏感组及耐药组,药物敏感组与耐药组间等位基因型频率比较,差异亦无统计学意义(P＞0.05).结论:本研究结果初步证实ABCB1基因C3435T位点多态性分布与耐药性癫痫之间无相关性.     

ABCB_1基因C3435T多态性与耐药性癫痫的关系

目的：探讨中国粤西地区汉族人群ABCB1基因C3435T（rs1045642）的单核苷酸多态性与耐药性癫痫的关系。方法：研究对象128例,包括正常对照组60例和癫痫组68例。根据患者对抗癫痫药物的反应性将癫痫组分为耐药组（30例）和药物敏感组（38例）。提取所有研究对象外周血基因组DNA,采用PCR扩增后基因测序鉴定ABCB1基因C3435T多态性。测定该位点基因型频率和等位基因频率,并进行统计学分析。结果：各组ABCB1基因C3435T基因型频率的分布符合Hardy-Weinburg平衡,提示其来自同一孟德尔群体。正常对照组与药物敏感组及耐药组,药物敏感组与耐药组间基因型频率比较,差异均无统计学意义（P〉0.05）。正常对照组与药物敏感组及耐药组,药物敏感组与耐药组间等位基因型频率比较,差异亦无统计学意义（P〉0.05）。结论：本研究结果初步证实ABCB1基因C3435T位点多态性分布与耐药性癫痫之间无相关性。     

多药耐药基因1C3435T多态性与癫痫耐药的关联性研究

目的：探讨我国癫痫患者P-糖蛋白基因多态性（C3435T）与抗癫痫药物反应性的关联性。方法：采用PCR--RFLP（聚合酶链反应--限制性片段长度多态性分析）的方法对156例癫痫患者外周血进行分型。其中,耐药组癫痫患者85例,有效组癫痫患者71例。结果：耐药组癫痫患者CC基因型21例,占24.70%;有效组癫痫患者CC基因型19例,占26.76%。两组比较无显著差异性。结论：本研究未发现P-gp C3435T基因型与癫痫耐药的关联性。     

多药耐药基因1 C3435T 多态性与癫痫耐药的关联性研究

目的:探讨我国癫痫患者P-糖蛋白基因多态性(C3435T)与抗癫痫药物反应性的关联性.方法:采用PCR-RFLP(聚合酶链反应-限制性片段长度多态性分析)的方法对156例癫痫患者外周血进行分型.其中,耐药组癫痫患者85例,有效组癫痫患者71例.结果:耐药组癫痫患者CC基因型21例,占24.70%;有效组癫痫患者CC基因型19例,占26.76%.两组比较无显著差异性.结论:本研究未发现P-gpC3435T基因型与癫痫耐药的关联性.     

中国人胎盘组织ABCB1基因多态性与P-gp表达水平的相关性

为了探讨中国人群胎盘组织中ABCB1基因单核苷酸多态性与其mRNA及蛋白表达水平的相关性,为妊娠期安全用药提供理论依据,本研究选取2016年6月至2018年5月于昆明医科大学第一附属医院正常分娩的200例中国汉族妇女的胎盘组织为研究对象,剪取母体侧胎盘组织,用于DNA、RNA和蛋白质的提取.通过测序确定ABCB1基因rs1045642、rs1128503及rs2032582多态性位点的基因型;采用实时荧光定量PCR和Western blot法测定组织中P-gp的mRNA和蛋白表达水平;对ABCB1基因多态性与P-gp的mRNA及蛋白表达水平的相关性进行分析.研究发现,对于rs1045642、rs1128503及rs2032582多态性位点,各基因型之间P-gp的mRNA及蛋白表达水平差异均无统计学意义(F=0.813,0.219,P＞0.05;F=0.132,0.086,P＞0.05;F=1.617,0.794,P＞0.05).本研究表明ABCB1 rs1045642、rs1128503及rs2032582基因多态性与中国汉族人群胎盘组织P-gp mRNA及蛋白表达水平可能无关.     

ABCB1、CES1 和 CYP2C19 基因多态性与 氯吡格雷抵抗的相关性研究进展

氯吡格雷是目前全球临床使用最为广泛的血小板受体抑制剂,但其抗血小板效应存在明显个体差异,部分病人服用常规剂量氯吡格 雷后存在抵抗现象,甚至发生不良临床事件。多项研究表明,ABCB1、CES1 和 CYP2C19 基因多态性对氯吡格雷抵抗的产生发挥重要作用。 简介氯吡格雷体内吸收与代谢机制和氯吡格雷抵抗的定义,综述 ABCB1、CES1 和 CYP2C19 基因多态性对氯吡格雷抵抗的影响。     

冬凌草活性部位逆转SGC7901/ADR细胞多药耐药性的体外研究

以SGC7901和SGC7901/ADR为细胞模型,检测了冬凌草活性部位与化疗药物联用后,对SGC7901/ADR耐药性的逆转效应;冬凌草活性部位处理细胞后,检测耐药细胞内阿霉素的蓄积变化、耐药细胞P-糖蛋白(P-gp)的表达水平以及mdr1基因的表达变化。结果显示,冬凌草氯仿部位和乙酸乙酯部位可以有效提高化疗药物阿霉素在SGC7901/ADR细胞内的蓄积,降低P-gp的表达,降低mdr1基因的转录。冬凌草逆转胃癌耐药细胞SGC7901/ADR多药耐药性的活性部位是冬凌草氯仿部位和乙酸乙酯部位,其逆转作用与抑制P-gp的表达相关。     

冬凌草活性部位逆转SGC7901/ADR细胞多药耐药性的体外研究北大核心CSCD

以SGC7901和SGC7901/ADR为细胞模型,检测了冬凌草活性部位与化疗药物联用后,对SGC7901/ADR耐药性的逆转效应;冬凌草活性部位处理细胞后,检测耐药细胞内阿霉素的蓄积变化、耐药细胞P-糖蛋白(P-gp)的表达水平以及mdr1基因的表达变化。结果显示,冬凌草氯仿部位和乙酸乙酯部位可以有效提高化疗药物阿霉素在SGC7901/ADR细胞内的蓄积,降低P-gp的表达,降低mdr1基因的转录。冬凌草逆转胃癌耐药细胞SGC7901/ADR多药耐药性的活性部位是冬凌草氯仿部位和乙酸乙酯部位,其逆转作用与抑制P-gp的表达相关。     

多药耐药基因产物在宫颈癌中的研究进展

化疗多药耐药是影响宫颈癌化疗疗效的重要因素.目前关于多药耐药(multidmgresistance,MDR)产生机制的研究报道很多,主要包括以下几个方面:(1)典型性多药耐药:如多药耐药基因1(multidrug resistance gene 1,MDRI)及其编码的蛋白P糖蛋白(P-glycoprotein,P-gp)、多药耐药相关蛋白(multidrug resistance-associated protein,MRP)和肺耐药蛋白(lung resistance-related protein,LRP)基因及其编码的蛋白的过度表达;(2)谷胱苷肤-S-转移酶-π的表达;(3)非典型性多药耐药:由拓扑异构酶Ⅱ(Topo Ⅱ)介导的耐药机制;(4)细胞凋亡抑制(例如:突变型P53和癌基因Her-2/neu/C-erbB-2表达增加)等.这些因素之问还可以相互影响、共同作用,造成宫颈癌对多种抗肿瘤药物的耐药[2].本文就多药耐药基因产物在宫颈癌中的研究进展进行综述.     

肿瘤MDR1基因表观遗传调控及其对宫颈癌的启示

多药耐药是肿瘤细胞化疗失败的重要原因,多药耐药基因1过度表达P-gP是产生耐药的主要机制,表观遗传通过对DNA的甲基化和组蛋白脱乙酰化的修饰来调节MDR1基因的转录.应用化学物质可以逆转MDR1基因的过度表达,提高化疗敏感性,这将为癌症治疗提供新策略,也为宫颈癌的治疗提供新思路.     

MDR1基因多态性及其临床相关性研究进展

体内外研究证明,人体中P—gP在药物的吸收、分布、代谢和排泄（ADME）过程中发挥了非常重要的作用。多药耐药基因MDR1（ABCB1）是P-gP的编码基因。药物基因组学和遗传药理学研究发现在不同个体中MDR1基因多态性与P—gP表达和功能的改变密切相关,而且这些多态位点存在基因型分布和等位基因频率的种族差异性。近几年,已陆续发现在MDR1基因中有50处单核苷酸多态性（SNPs）和3处插入与缺失多态性。随后,大量文献报道某些位点的SNPs如C3435T会使个体患病的易感性增加。因此人们相信,深入研究MDR1基因多态性与P—gP的生理和生化方面的相关性将对个体医疗有着非常深远的意义。文章总结了国外最新的研究进展并结合本实验室的工作着重讨论了4个方面：1）P—gP对药代动力学性质的影响：2）MDR1基因多态性及其对遗传药理学性质的影响;3）MDR1^C3435T的单核苷酸多态性与P-gP表达和功能之间的相关性：4）MDR1基因多态性与人类某些疾病之间的相关性。     

Association of MDR1 C3435T polymorphism with bipolar disorder in patients treated with valproic acid

P-glycoprotein (P-gp), an efflux transporter protein, is an ABC transporter encoded by the multidrug resistance 1 gene (MDR1, ABCB1). The common synonymous C3435T polymorphism in exon 26 is reported to associate with lower P-gp functional expression and drug uptake. Many extended pharmacogenomics, functional, and complex disease association studies focused mainly on this polymorphism. We investigated the association of exon 26 C3435T genetic variants of MDR1 gene with susceptibility to bipolar disorder and serum valproic acid concentration. Totally, 104 patients meeting DSM-IV criteria for bipolar disorder and 169 controls were admitted to the study. There was statistically significant difference between the genotypes of bipolar patients (CT 91.2%, TT 6.8%, and CC 2%) and controls (CT 52.7%, TT 26%, CC 21.3%) although their allelic distribution was similar. The serum valproic acid concentrations of the patients with CT, TT and CC genotypes were 72.92 ± 20.55, 80.47 ± 14.01 and 68.29 ± 12.17 μg/ml, respectively, and there was no significant difference between the C3435T genotypes.     

Absence of a general association between ABCB1 genetic variants and response to antiepileptic drugs in epilepsy patients

Over-expression of efflux transporter P-glycoprotein (PgP) encoded by ABCB1 gene has been implicated in poor responsive epilepsy. Several genetic variants have been shown to influence the expression levels of P-glycoprotein. The aim of the present study was to investigate the role of ABCB1 polymorphisms: C1236T, G2677T/A and C3435T in determining drug response to first line antiepileptic drugs (AEDs) namely phenobarbitone, phenytoin, carbamazepine and valproate in North Indian cohort of epilepsy patients. DNA samples were obtained from 392 consecutive epilepsy patients, out of which 228 had completed follow-up evaluation at 12 months. After attaining steady state of the AEDs in the first two months of study, 133 patients showed complete freedom from seizures (no-seizure group) and 95 patients continued to have seizures (recurrent-seizures group) in the remaining period of study. Comparison of “no-seizure” and “recurrent-seizures” groups revealed no significant differences in allelic, genotypic and haplotypic frequencies for all the studied variants. In conclusion, our finding disproves a general association between ABCB1 polymorphisms and drug response in epilepsy patients.     

MDR1 gene polymorphisms may be associated with Behçet's disease and its colchicum treatment response

Behçet's disease (BD) is a chronic multisystem disorder. Infectious agents, immune system mechanisms, and genetic factors are implicated in the etiopathogenesis of BD, which remains to be explained. The human MDR1 (ABCB1) gene encoder P-glycoprotein (P-gp) plays a key role in drug disposition, serves as a protective mechanism against xenobiotics, and provides additional protection for the brain, testis, and fetus. We investigated the genotype and haplotype distributions of three MDR1 gene polymorphisms (C1236T, G2677T/A, and C3435T) in 104 BD patients and 130 control subjects. The genotyping analysis was performed by using PCR–RFLP methods.     

The stabilisation of purified, reconstituted P-glycoprotein by freeze drying with disaccharides

The drug efflux pump P-glycoprotein (P-gp) (ABCB1) confers multidrug resistance, a major cause of failure in the chemotherapy of tumours, exacerbated by a shortage of potent and selective inhibitors. A high throughput assay using purified P-gp to screen and characterise potential inhibitors would greatly accelerate their development. However, long-term stability of purified reconstituted ABCB1 can only be reliably achieved with storage at −80 °C. For example, at 20 °C, the activity of ABCB1 was abrogated with a half-life of <1 day. The aim of this investigation was to stabilise purified, reconstituted ABCB1 to enable storage at higher temperatures and thereby enable design of a high throughput assay system. The ABCB1 purification procedure was optimised to allow successful freeze drying by substitution of glycerol with the disaccharides trehalose or maltose. Addition of disaccharides resulted in ATPase activity being retained immediately following lyophilisation with no significant difference between the two disaccharides. However, during storage trehalose preserved ATPase activity for several months regardless of the temperature (e.g. 60% retention at 150 days), whereas ATPase activity in maltose purified P-gp was affected by both storage time and temperature. The data provide an effective mechanism for the production of resilient purified, reconstituted ABCB1.     

Up-Regulation of Epithelial Membrane Protein-1 in the Temporal Neocortex of Patients with Intractable Epilepsy

Epithelial membrane protein-1 (EMP-1), called Tumor-associated membrane protein, is the marker of a drug-resistant tumor and take part in the drug-resistant mechanism of tumor, with the relationship of epidermal growth factor receptor (EGFR). Because there are some similarities between the pathogenesis and the drug resistance mechanism of tumor and the drug resistance mechanisms in epilepsy. EMP1 expression may be connected with the drug-resistance mechanism of epilepsy. We detected EMP-1 by gene scanning and immunohistochemistry staining, comparing the IE group and the control group, and we investigated the relationship between EMP-1 and EGFR by double-label immunofluorescence staining in the IE group. We found expression of EMP-1 mRNA was higher in IE per the gene scanning, EMP-1 immunoreactivity was apparent in neurons of IE patients but not in the control group, and the expression of EMP-1 and EGFR occurred in the same neuron. We confirm EMP-1 is abnormally expressed in IE and suggest the interaction of EGFR and EMP-1 plays a role in the mechanism of drug resistance in epilepsy and may be a new gene for drug resistance.     

MDR1 Gene Polymorphisms and Clinical Relevance

In vivo and in vitro studies have demonstrated that P-glycoprotein (P-gp) plays a very significant role in the ADME processes (absorption, distribution, metabolism, excretion) and drug-drug interaction (DDI) of drugs in humans. P-gp is the product of multidrug resistance gene (MDR1/ABCB1). Pharmacogenomics and pharmacogenetics studies have revealed that genetic polymorphisms of MDR1 are associated with alteration in P-gp expression and function in different ethnicities and subjects. By now, 50 single nucleotide polymorphisms (SNPs) and 3 insertion/deletion polymorphisms have been found in the MDR1 gene. Some of them, such as C3435T, have been identified to be a risk factor for numerous diseases. It is believed that further understanding of the physiology and biochemistry of P-gp with respect to its genetic variations may be important for individualized pharmacotherapy. Therefore, based on the latest public information and our studies, this review focuses on the following four aspects: 1) the impact of P-gp on pharmacokinetics; 2) MDR1 genetic polymorphisms and their impacts on pharmacogenetics; 3) relationship between altered P-gp expression and function and the MDR1^C3435T SNP, and 4) relevance of MDR1 polymorphisms to certain human diseases.     

Drug resistance in epilepsy and the ABCB1 gene: The clinical perspective

Multidrug resistance is one of the most serious problems in the treatment of epilepsy that is likely to have a complex genetic and acquired basis. Various experimental data support the hypothesis that over-expression of antiepileptic drug (AED) transporters may play a pivotal role in drug resistance. Hyyt 6however, key questions concerning their functionality remain unanswered. The idea that P-glycoprotein, encoded by the ABCB1 gene, might mediate at least part of the drug resistance was met with both enthusiasm and skepticism. As in oncology, initial optimism has been clouded subsequently by conflicting results. The first study reporting a positive association between genetic variation in the P-glycoprotein and multidrug-resistant epilepsy was published in 2003. Since then, several other genetic association studies have attempted to verify this result. However, taken overall, the role of P-glycoprotein in drug resistance in epilepsy still remains uncertain. We intend to critically review the inherent problems associated with epilepsy pharmacogenetic studies in general and with ABCB1 polymorphisms studies in particular. The lessons learnt from the ABCB1 studies can help us to guide future association genetics studies to investigate AED resistance, and thereby taking us closer to the cherished dream of personalized AED therapy.     

Effect of Stemona curtisii root extract on P-glycoprotein and MRP-1 function in multidrug-resistant cancer cells

Multidrug resistance (MDR) is the result of overexpression of membrane bound proteins that efflux chemotherapeutic drugs from the cells. Two proteins, P-glycoprotein (P-gp) and multidrug-resistance associated protein-1 (MRP-1) efflux chemotherapeutic agents out of the cancer cell that decrease intracellular drug accumulation, thereby decreasing the effectiveness of many chemotherapeutic agents. In the present study, the ethanolic extract of the roots of Stemona curtisii Hook. was tested for the potential ability to modulate the MDR phenotype and function of P-gp and MRP-1. The S. curtisii extract reversed the resistance to putative chemotherapeutic agents, including vinblastine, paclitaxel and colchicine of KB-V1 cells (MDR human cervical carcinoma with high P-gp expression) in a dose-dependent manner, but not in KB-3-1 cells (drug sensitive human cervical carcinoma, which lack P-gp expression). The root extract also increased the intracellular uptake and retention of (3)[H]-vinblastine in KB-V1 cells dose dependently. The extract did not influence MDR phenotype-mediated MRP-1 in MRP1-HEK293 (human embryonic kidney cells stably transfected with pcDNA3.1-MRP1-H10 which show high MRP-1 expression) and pcDNA3.1-HEK293 (wild type). In summary, the S. curtisii root extract modulated P-gp activity but not MRP-1 activity. The result obtained from this study strongly indicated that S. curtisii extract may play an important role as a P-gp modulator as used in vitro and may be effective in the treatment of multidrug-resistant cancers. The purified form of the active components of S. curtisii extract should be investigated in more details in order to explain the molecular mechanisms involved in P-gp modulation. This is the first report of new biological activity in this plant, which could be a potential source of a new chemosensitizer.     

Effects of plant sterols on human multidrug transporters ABCB1 and ABCC1

The effects of dietary plant sterols on human drug efflux transporters P-glycoprotein (P-gp, ABCB1) and multidrug resistance protein 1 (MRP1, ABCC1) were investigated using P-gp-overexpressing human carcinoma KB-C2 cells and human MRP1 gene-transfected KB/MRP cells. The effects of natural phytosterols found in foods, herbs, and dietary supplements such as β-sitosterol, campesterol, stigmasterol, fucosterol, and z-guggulsterone were investigated. The accumulation of daunorubicin or rhodamine 123, fluorescent substrates of P-gp, increased in the presence of guggulsterone in KB-C2 cells. The efflux of rhodamine 123 from KB-C2 cells was inhibited by guggulsterone. Guggulsterone also increased the accumulation of calcein, a fluorescent substrate of MRP1, in KB/MRP cells. The ATPase activities of P-gp and MRP1 were stimulated by guggulsterone. These results suggest that guggulsterone, a natural dietary hypolipidemic agent have dual inhibitory effects on P-gp and MRP1 and the potencies to cause food-drug interactions.