多药耐药相关蛋白及其在肿瘤耐药中的作用

多药耐药(multidrug resistance,MDR)是导致肿瘤患者化疗失败的主要原因。介导多药耐药的重要机制之一是多药耐药相关蛋白(multidrug resistance-associated proteins,MRPs)的表达增加。MRPs是一类ATP能量依赖型跨膜转运蛋白,是具有选择性和特异性的药物外排泵。本文主要针对MRPs的生理特征、结构特点、耐药谱特征及其逆转进行综述。     

基于多药耐药相关蛋白2(Abcc2/Mrp2)在大鼠肾脏表达性别差异的氧氟沙星药动学变化(英文)

本研究旨在探讨基于多药耐药相关蛋白2(Abcc2/Mrp2)在大鼠肾脏表达性别差异的氧氟沙星的药代动力学变化。采用高效液相色谱法(HPLC)分别测定经尾静脉注射给予氧氟沙星(30 mg.kg1)后大鼠血浆和尿液中氧氟沙星的浓度;通过免疫组化法和流式细胞术分别对雄性和雌性大鼠肾脏Mrp2的表达进行定性和定量分析。结果表明在雄性大鼠体内,氧氟沙星药时曲线下面积(AUC)明显小于雌性大鼠,而尿排总量明显大于雌性大鼠;Mrp2在雄性大鼠肾脏中的表达显著高于雌性大鼠。因此,氧氟沙星药动学性别差异可能是由Mrp2在雄性和雌性大鼠肾脏中的表达差异所引起的。     

多药耐药相关蛋白与药物耐受性

药物耐受性是导致多种疾病治疗失败的主要原因,而多药耐药(MDR)的产生是发生耐药的主要形式,MDR包括三种形式:(1)典型MDR,即多药耐药基因(MDRI)及其编码的细胞膜P-糖蛋白(PgP)表达增强所致;(2)非典型MDR,由谷胱甘肽解毒酶系统(GST)活性增高,DNA拓扑异构酶Ⅱ(TOPOⅡ)活性降低或结构异常,DNA操作修复能力增强组成;(3)多药耐药相关蛋白(MRP)基因的扩增或过度表达。近年来,对多药耐药相关蛋白的研究较多,获得了大量成功,综述如下:     

不同剂量亚砷酸钠染毒大鼠多药耐药相关蛋白2表达水平的变化

目的 观察不同剂量亚砷酸钠染毒大鼠肝细胞膜转运蛋白-多药耐药相关蛋白2（multidrug resistance associated protein2，MRP2）表达水平的变化及与砷代谢的关系。     

酚红外排水平评价肺上皮细胞多药耐药相关蛋白1的功能

目的：以酚红为多药耐药相关蛋白1（MRP1）的底物,丙磺舒为其抑制剂,通过酚红的外排水平建立评价肺上皮细胞MRP1的功能的方法。方法：小鼠静脉注射酚红（250mg/kg）,30min后进行肺泡灌洗,测定灌洗液中酚红的浓度,并以雾化吸入MRP1特异性抑制剂丙磺舒（150mg/kg）作为对照,观察给予抑制剂前后灌洗液中酚红浓度及灌洗液中酚红浓度/血浆中酚红浓度比值的变化,来评价小鼠肺上皮细胞MRP1功能的改变。结果：与未给予抑制剂相比,给予MRP1抑制剂丙磺舒后,血浆中酚红浓度无显著性差异,但与未给予抑制剂相比,给予MRP1抑制剂丙磺舒60min后,其肺泡灌洗液中酚红浓度、灌洗液中酚红浓度/血浆中酚红浓度比值显著性降低。结论：肺泡灌洗液中酚红的外排水平反映小鼠肺上皮细胞MRP1功能的改变。     

转运蛋白与药物代谢动力学、多药耐药关系的研究进展

目的介绍近年来转运蛋白与药物代谢动力学、多药耐药关系的最新进展。方法依据文献对转运蛋白与药物代谢动力学、多药耐药关系的研究进展进行综述。结果转运蛋白影响药代过程,反复接触同一药物则可能产生多药耐药,如何有效利用转运蛋白的各种特性研发药物成为热点。结论深入地分析转运蛋白的理化特性、药物代谢动力学过程和多药耐药,从而设计出更安全有效的药物。     

多药耐药相关蛋白1及其与肿瘤关系的研究进展

多药耐药（MDR）是导致临床肿瘤化疗失败的重要原因。多药耐药相关蛋白1（MRP1/ABCC1）被认为是介导肿瘤多药耐药的主要跨膜转运蛋白之一。 探究MRP1/ABCC1的结构、功能,以及与肿瘤的关系,有利于指导临床合理用药和肿瘤预后的评估。     

c—jun氨基末端激酶与多药耐药相关蛋白1在结直肠癌组织中的表达

目的研究磷酸化c-jun氨基末端激酶（JNK）与多药耐药相关蛋白1（MRP1）在结直肠癌组织中的表达及JNK在结直肠癌耐药中的可能机制。方法通过免疫组织化学方法研究72例结直肠癌和4JD例正常大肠组织中JNK和MRP1蛋白表达及其关系。结果JNK和MRP1蛋白在结直肠癌组织中的阳性表达率分别为47．22％和51．39％,均明显高于在正常大肠组织中的表达。JNK蛋白阳性表达与结直肠癌患者的性别、年龄、肿瘤大小、部位均无明显相关性（P〉0．05）,而与肿瘤分化、淋巴结转移、远处转移及Dukes分期显著相关（P〈0．05）。MRP1蛋白阳性表达与结直肠癌患者的性别、年龄、肿瘤大小、部位及肿瘤分化均无明显相关性（P〉0．05）,而与淋巴结转移、远处转移及Dukes分期显著相关（P〈0．05）。结论JNK高表达与结直肠癌的发生及其恶性生物学行为相关,其可能通过上调MRP1的表达参与大肠癌化疗耐药的形成。     

外排型转运体与肿瘤多药耐药

肿瘤多药耐药（MDR）是导致肿瘤化疗失败的主要原因之一。肿瘤MDR的机制有多种,其中外排型转运体的过表达是导致MDR的主要机制,因此研究外排型转运体介导的肿瘤MDR机制和发现可以逆转肿瘤MDR的抑制剂成为国内外研究的热点。就目前研究的3种三磷酸腺苷结合盒转运体：P-糖蛋白、多药耐药相关蛋白、乳腺癌耐药蛋白介导的MDR及逆转MDR的机制进行综述,以期为提高肿瘤治疗疗效提供依据。     

多药耐药相关蛋白1和CD34在大肠癌组织中的表达及其意义

目的 探讨多药耐药相关蛋白1(MRP1)和小血管内皮细胞标志物CD34在大肠癌组织中的表达及其与临床病理指标的关系.方法 应用免疫组织化学法对53例大肠癌患者的癌组织、正常组织中MRP1和CD34表达进行检测,将结果与临床病理指标进行分析.结果 MRP1在大肠癌及正常组织的阳性表达率分别为49.1％和15.1％,差异有统计学意义(x2=14.029,P＜0.01).MRP1的表达与分化程度、浸润深度、淋巴结转移等病理特征均无关.CD34在大肠癌及正常组织的表达分别为(35.63±12.23) MVD/HP和(6.12 ±0.97) MVD/HP,差异有统计学意义(t=17.565,P＜0.01).CD34的表达与年龄、性别、肿瘤大小、生长部位均无关,与Dukes分期、淋巴结转移、分化程度、肠壁浸润深度均有关(均P＜0.05).结论 MRP1和CD34在大肠癌组织中高表达,可能与大肠癌的发生有关;MRP1可能与原发性多药耐药性有关,CD34可能参与了大肠癌的侵袭和转移,联合检测可为大肠癌的诊治和预后评估提供新的参考指标.     

Multidrug resistance-associated proteins and implications in drug development

1.  The multidrug resistance-associated proteins (MRPs) belong to the ATP-binding cassette superfamily (ABCC family) of transporters that are expressed differentially in the liver, kidney, intestine and blood–brain barrier. There are nine human MRPs that transport a structurally diverse array of endo- and xenobiotics as well as their conjugates.
2.  Multidrug resistance-associated protein 1 can be distinguished from MRP2 and MRP3 by its higher affinity for leukotriene C₄. Unlike MRP1, MRP2 functions in the extrusion of endogenous organic anions, such as bilirubin glucuronide and certain anticancer agents. In addition to the transport of glutathione and glucuronate conjugates, MRP3 has the additional capability of mediating the transport of monoanionic bile acids.
3.  Both MRP4 and MRP5 are able to mediate the transport of cyclic nucleotides and confer resistance to certain antiviral and anticancer nucleotide analogues. Hereditary deficiency of MRP6 results in pseudoxanthoma elasticum. In the body, MRP6 is involved in the transport of glutathione conjugates and the cyclic pentapeptide BQ123.
4.  Various MRPs show considerable differences in tissue distribution, substrate specificity and proposed physiological function. These proteins play a role in drug disposition and excretion and thus are implicated in drug toxicity and drug interactions. Increased efflux of natural product anticancer drugs and other anticancer agents mediated by MRPs from cancer cells is associated with tumour resistance.
5.  A better understanding of the function and regulating mechanisms of MRPs could help minimize and avoid drug toxicity and unfavourable drug–drug interactions, as well as help overcome drug resistance.     

西替利嗪肠吸收机制研究

目的:考察西替利嗪在小肠的吸收特征.方法:采用离体肠外翻法,以HPLC法测定不同浓度西替利嗪在大鼠各肠段的吸收量,并分别计算吸收速率常数(Ka)和表观渗透系数.考察P-糖蛋白(P-gp)抑制剂地高辛和多药耐药相关蛋白-2(Mrp-2)抑制剂丙磺舒对西替利嗪肠吸收的影响.结果:西替利嗪在各肠段均有较好的吸收,Ka和表观渗透系数按空肠、十二指肠、结肠和回肠依次下降.各肠段累积吸收量与浓度呈非线性关系,高浓度时吸收加快.P-gp抑制剂地高辛使西替利嗪的吸收明显增加,而Mrp-2抑制剂丙磺舒对西替利嗪的肠吸收没有明显影响.结论:西替利嗪的转运受P-gp介导,临床应用中需注意P-gp及其底物对西替利嗪体内过程的影响.     

Multidrug resistance-associated protein 2 (MRP2) affects hepatobiliary elimination but not the intestinal disposition of tenofovir disoproxil fumarate and its metabolites

The role of multidrug resistance-associated protein 2 (MRP2) on the intestinal disposition and hepatobiliary elimination of tenofovir disoproxil fumarate (DF) and its metabolites [tenofovir (mono)ester and tenofovir] was studied in the Caco-2 system, Ussing chambers and rat in-situ efflux experiments. In the Caco-2 model and Ussing chambers, no statistically significant differences in transport could be observed when the MRP inhibitor probenecid was included. In Ussing chambers, transport was also similar when using intestinal tissue from MRP2-deficient rats. After intravenous administration of tenofovir DF, the excretion of tenofovir [(mono)ester] in bile was significantly decreased in MRP2-deficient rats and in rats treated with probenecid. The area under the blood concentration–time curve was increased in MRP2-deficient rats [1.0?±?0.1 and 0.36?±?0.03?µM.min^?1 for tenofovir and tenofovir (mono)ester, respectively] and rats treated with probenecid (1.42?±?0.04 and 0.36?±?0.02?µM.min^?1) compared with control rats (0.64?±?0.05 and 0.15?±?0.06?µM.min^?1). The appearance of tenofovir [(mono)ester] in intestinal perfusate was similar in control rats upon co-administering probenecid or when using MRP2-deficient rats. In conclusion, MRP2 appeared to have no modulatory effect on the intestinal disposition of tenofovir and tenofovir (mono)ester. However, inhibition (probenecid) or the total absence of MRP2 (MRP2-deficient rats) significantly reduced hepatobiliary elimination, which was accompanied by increased systemic exposure.     

药物的肠吸收与处置研究进展

对近几年药物肠吸收与处置方面的研究进展进行了综述。包括:特定部位吸收、代谢的认识和利用,与药物首过效应有关的肠壁外泌及代谢作用的介绍,促进药物肠道吸收的方法及常用研究模型的比较。     

肠道转运蛋白在药物吸收中的重要作用

1引言 分子生物学和遗传基因学的发展使得对载体介导膜转运的认识提高到了分子基因水平.转运蛋白的存在在很大程度上决定了某些药物向靶部位及非靶部位的分布特征.     

Multidrug resistance-associated protein 1 decreases the concentrations of antiepileptic drugs in cortical extracellular fluid in amygdale kindling rats

Aim:

To investigate whether multidrug resistance-associated protein 1 (MRP1) was responsible for drug resistence in refractory epilepsy in amygdale kindling rats.

Methods:

Rat amygdale kindling was used as a model of refractory epilepsy. The expression of MRP1 mRNA and protein in the brains was examined using RT-PCR and Western blot. MRP1-positive cells in the cortex and hippocampus were studied with immunohistochemical staining. The rats were intraperitoneally injected with phenytoin (50 mg/kg) or carbamazepine (20 mg/kg), and their concentrations in the cortical extracellular fluid were measured using microdialysis and HPLC. Probenecid, a MRP1 inhibitor (40 mmol/L, 50 μL) was administered through an inflow tube into the cortex 30 min before injection of the antiepileptic drugs.

Results:

The expression of MRP1 mRNA and protein was significantly up-regulated in the cortex and hippocampus in amygdale kindling rats compared with the control group. Furthermore, the number of MRP1-positive cells in the cortex and hippocampus was also significantly increased in amygdale kindling rats. Microdialysis studies showed that the concentrations of phenytoin and carbamazepine in the cortical extracellular fluid were significantly decreased in amygdale kindling rats. Pre-administration of probenecid could restore the concentrations back to their control levels.

Conclusion:

Up-regulation of MRP1 is responsible for the resistance of brain cells to antiepileptic drugs in the amygdale kindling rats.     

MRP1在上皮性卵巢癌中的表达及临床意义

目的:探讨多药耐药相关蛋白1(MRP1)在上皮性卵巢癌中的表达及临床意义。方法:以免疫组化法检测34例原发性上皮性卵巢癌(POEC)、12例临界恶性上皮性卵巢瘤和14例良性上皮性卵巢瘤组织中的MRP1,并对POEC组中17例经顺铂化疗后二次手术癌组织进行MRP1检测。结果:(1)POEC组织中MRP1的表达高于良性卵巢瘤(P<0.05),与临界恶性瘤相比,差别无统计学意义(P>0.05);临界恶性瘤与良性瘤相比,表达明显增强,但差别无统计学意义(P=0.11)。(2)MRP1的表达与患者年龄、组织类型、临床分期、腹水和残余灶均无关,只与细胞分级有关(P=0.006)。(3)化疗后MRP1阳性表达率显著高于化疗前(P=0.008);MRP1阳性患者近期化疗有效率显著低于阴性表达者(P=0.017),其3年、5年生存率也较后者降低,但差异无统计学意义(P=0.07,P=0.17)。结论:顺铂可诱导POEC组织中MRP1表达,检测MRP1可预测近期化疗疗效,指导临床化疗方案的选择。     

Almitrine bismesylate disposition in the human digestive tract

Summary The absorption of almitrine from the upper gastrointestinal tract has been evaluated in 6 healthy volunteers by an intubation technique. Almitrine bismesylate dissolved in malic acid was introduced into the stomach after homogenization with a meal containing the marker¹⁴C-polyethylene glycol (PEG) 4000. Unlabeled PEG 4000 was infused into the second part of duodenum throughout the experiment. Samples of the luminal content were collected every 15 min for four hours from the stomach and at the ligament of Treitz. Blood was also collected.Almitrine was neither absorbed from nor metabolized in the stomach. About 37% of the quantity of drug emptied from the stomach was absorbed from the duodenum. Almitrine was detected in plasma 50 min after ingestion of the meal and its plasma concentration-time profile reflected the cumulative gastric emptying rate. The metabolite tetrahydroxy almitrine was found in intestinal samples as soon as unchanged drug was detected in plasma. The intraluminal rate of formation of the metabolite increased with time.The results suggest hepatic metabolism of almitrine followed by rapid excretion of the metabolite in the bile.