靶向逆转P糖-蛋白介导肿瘤多药耐药的研究进展

P-糖蛋白(P-gp)的过度表达与肿瘤细胞的多药耐药性(MDR)密切相关,被认为是导致肿瘤化疗失败的主要原因之一.综述近年在P-gp的结构与功能、影响mdr-1表达调控因素、逆转P-gp介导MDR的潜在靶点等方面的研究进展.     

中草药在促进西药吸收和提高血药浓度方面的作用

分类综述近年来有关利用中草药及其活性成分促进西药吸收和提高血药浓度及其作用机制的研究报道。某些中草药的活性成分可以通过提高吸收性上皮细胞膜的通透性、抑制外排蛋白和代谢酶，增加西药的体内吸收和血药浓度。     

P-糖蛋白介导的肿瘤多药耐药与逆转

最近数十年,一些ATP依赖的药物外排泵被证实与肿瘤的多药耐药（MDR）有关。ATP结合盒（ATP—binding cassette,ABC）蛋白是一个结合蛋白大家族,由ABC基因编码,在真核生物和原核生物中都有表达。     

重视中药作用于肠道CYP3A4、P-gp后对口服药物生物利用度的影响

目的:提高中西药品联合使用的合理性。方法:归纳中药或中药化学成分对肠道细胞色素P450酶3A4(CYP3A4)及P-糖蛋白(P-gp)的抑制或诱导作用而改变口服底物药物生物利用度参数的机制,并结合文献资料分析说明。结果:五味子、当归、吴茱萸次碱、银杏内酯A等对CYP3A4有抑制或诱导作用;黄芩、贯叶连翘、柚皮素、金丝桃素等对P-gp有抑制或诱导作用。中药及中药化学成分作用肠道CYP3A4、P-gp对底物药物生物利用度参数的改变作用,可影响药品使用的安全性和有效性。结论:临床医药专业技术人员应重视中西药联合使用中存在的药物相互作用,才能促进用药合理性的提高。     

P-糖蛋白抑制药逆转肿瘤多药耐药的研究进展

P-糖蛋白（permeability glycoprotein，P-gp）过度表达是多药耐药（multidrug resistance，MDR）产生的主要原因，P-糖蛋白抑制药可以抑制P-糖蛋白对肿瘤药物的外排作用，使肿瘤细胞内的药物浓度提高，从而逆转肿瘤MDR，第3代P-糖蛋白抑制药具有高效、低毒、选择性高等特点，中药可以通过多种途径抑制P-糖蛋白的表达和功能，从而逆转MDR。     

P-gp及对抗P-gp介导多药耐药的研究现状

P-糖蛋白在多药耐药中起着重要的作用。本文就P-gp的蛋白结构、作用机制及其与多药耐药的关系以及对抗P-gp介导的MDR的现状做了简要介绍。总之，一方面要继续开发高效的P-gp抑制剂，同时，又要考虑过度抑制P-gp可能会带来不良影响；在抑制P-gp的同时，还要兼顾对其它耐药机制的抑制，只有这样，才能在临床上充分解决多药耐药的问题。     

CYP3A4和P糖蛋白与药物的肠道处置

肠CYP3A4介导的生物转化和P糖蛋白介导的药物主动泵出肠细胞是决定口服药物生物利用度的主要因素。有证据显示CYP3A4和P糖蛋白在小肠不是共同调节的,但两者在药物肠道处置中的协同作用已得到体外试验和动物体内试验的证实。进一步了解两者的相互作用有助于改善CYP3A4/P糖蛋白底物的生物利用度。     

P-糖蛋白介导的多药耐药及其逆转剂的研究进展

多药耐药(multidrug resistance,MDR)[1]是指肿瘤细胞对1种抗肿瘤药物产生耐药性的同时,对结构和作用机制完全不同的其他多种抗肿瘤药物产生交叉耐药性,是一种独特的广谱耐药现象[2]。MDR由多种途径诱导,可分为经典和非经典MDR     

P-糖蛋白介导的多药耐药及其逆转剂的研究进展

多药耐药(multidrug resistance,MDR)[1]是指肿瘤细胞对1种抗肿瘤药物产生耐药性的同时,对结构和作用机制完全不同的其他多种抗肿瘤药物产生交叉耐药性,是一种独特的广谱耐药现象[2].MDR由多种途径诱导,可分为经典和非经典MDR两大机制.MDR是肿瘤化疗的一个主要的障碍.抗肿瘤药物在肿瘤细胞积累的下降,可被几种膜蛋白质调节,这些膜蛋白质属于ATP结合的盒式(ATP binding cassette,ABC)运输蛋白家族成员,P-糖蛋白(P-gp)属于这个蛋白家族.P-gp是一种ATP依赖性的跨膜外流泵,它可通过细胞膜转运多种抗肿瘤药,从而限制这些抗肿瘤药进入细胞而导致肿瘤细胞耐药.据此,研究学者着力于寻找抑制P-gp的分子,以逆转肿瘤化疗药的耐药性.近年来由于中药资源丰富,作用靶点多,可针对MDR机制复杂的特点,有学者开始开发逆转肿瘤MDR的中药.     

卵巢癌多药耐药治疗的研究进展

卵巢癌化疗多药耐药(multidrug resistance,MDR)的发生和发展是多基因参与的极其复杂的过程,其发生机制目前尚不十分明确.既往的研究着重在开发小分子抑制剂靶向多药耐药基因编码的P-糖蛋白逆转多药耐药,但效果不佳.本文总结了近年来对卵巢癌多药耐药发生机制的研究进展以及克服卵巢癌治疗中MDR问题的新方案,包括新型的P-糖蛋白抑制剂,靶向肿瘤干细胞和微小核糖核酸(miRNAs),自噬信号通路调节等,为临床卵巢癌多药耐药的治疗提供参考.     

Comparative analysis of substrate and inhibitor interactions with CYP3A4 and CYP3A5

To evaluate the role that cytochrome (CYP) 3A5 plays in hepatic drug metabolism, the substrate selectivity and inhibitory potential of over 60 compounds towards CYP3A4 and CYP3A5 were assessed using Escherichia coli recombinant cell lines. CYP3A4-mediated metabolism predominated for many of the compounds studied. However, a number of drugs gave similar CL_int estimates using CYP3A5 compared with CYP3A4 including midazolam (CL_int?=?3.4 versus 3.3?µl?min^–1?pmol^–1). Significant CYP3A5-mediated metabolism was also observed for several drugs including mifepristone (CL_int?=?10.3 versus 2.4?µl?min^–1?pmol^–1), and ritonavir (CL_int?=?0.76 versus 0.47?µl?min^–1?pmol^–1). The majority of compounds studied showed a greater inhibitory potential (IC₅₀) towards CYP3A4 compared with CYP3A5 (eightfold lower on average). A greater degree of time-dependent inhibition was also observed with CYP3A4 compared with CYP3A5. The range of compounds investigated in the present study extends significantly previous work and suggests that CYP3A5 may have a significant role in drug metabolism particularly in populations expressing high levels of CYP3A5 and/or on co-medications known to inhibit CYP3A4.     

MDR- and CYP3A4-Mediated Drug–Drug Interactions

P-glycoprotein (P-gp), multiple drug resistance associated proteins (MRPs), and cytochrome P450 3A4 together constitute a highly efficient barrier for many orally absorbed drugs. Multidrug regimens and corresponding drug–drug interactions are known to cause many adverse drug reactions and treatment failures. Available literature, clinical reports, and in vitro studies from our laboratory indicate that many drugs are substrates for both P-gp and CYP3A4. Our primary hypothesis is that transport and metabolism of protease inhibitors (PIs) and NNRTIs will be altered when administered in combination with azole antifungals, macrolide, fluroquinolone antibiotics, statins, cardiovascular agents, immune modulators, and recreational drugs [benzodiazepines, cocaine, lysergic acid dithylamide (LSD), marijuana, amphetamine (Meth), 3,4-methylenedioxymethamphetamine (MDMA), and opiates] due to efflux, and/or metabolism at cellular targets. Therefore, such drug combinations could be a reason for the unexpected and unexplainable therapeutic outcomes. A number of clinical reports on drug interaction between PIs and other classes (macrolide antibiotics, azole antifungals, cholesterol lowering statins, cardiovascular medicines, and immunomodulators) are discussed in this article. MDCKII-MDR1 was employed as an in vitro model to evaluate the effects of antiretrovirals, azole antifungals, macrolide, and fluroquinolone antibiotics on efflux transporters. Ketoconazole (50 μM) enhanced the intracellular concentration of ³H ritonavir. The inhibitory effects of ketoconazole and MK 571 on the efflux of ³H ritonavir were comparable. An additive effect was observed with simultaneous incorporation of ketoconazole and MK 571. Results of ³H ritonavir uptake studies were confirmed with transcellular transport studies. Several fluroquinolones were also evaluated on P-gp-mediated efflux of ³H cyclosporin and 14C erythromycin. These in vitro studies indicate that grepafloxacin, levofloxacin, and sparfloxacin are potent inhibitors of P-gp-mediated efflux of 14C erythromycin and ³H cyclosporin. Simultaneous administration of fluoroquinolones and macrolides could minimize the efflux and metabolism of both of the drugs. Effects of erythromycin and ketoconazole on carbamazepine metabolism were examined. Formation of 10,11-epoxy carbamazepine, a major CBZ metabolite, was significantly inhibited by these agents. Therefore, drug efflux proteins (P-gp, MRPs) and metabolizing enzyme (CYP450) are major factors in drug interactions. Overlapping substrate specificities of these proteins result in complex and sometimes perplexing pharmacokinetic profiles of multidrug regimens. Drug–drug interactions with PIs and other coadministered agents for human immunodeficiency virus (HIV) positive population have been discussed in light of efflux transporters and metabolizing enzymes. This article provides an insight into low and variable oral bioavailability and related complications leading to loss of therapeutic activity of MDR and CYP 450 substrates.     

Pharmacokinetics of midazolam in CYP3A4- and CYP3A5-genotyped subjects

Objective We investigated whether differences in pharmacokinetics of midazolam, a CYP3A probe, could be demonstrated between subjects with different CYP3A4 and CYP3A5 genotypes.Methods Plasma concentrations of midazolam, and of total (conjugated + unconjugated) 1OH-midazolam, and 4OH-midazolam were measured after the oral administration of 7.5 mg or of 75 µg of midazolam in 21 healthy subjects.Results CYP3A5*7, CYP3A4*1E, CYP3A4*2, CYP3A4*4, CYP3A4*5, CYP3A4*6, CYP3A4*8, CYP3A4*11, CYP3A4*12, CYP3A4*13, CYP3A4*17 and CYP3A4*18 alleles were not identified in the 21 subjects. CYP3A5*3, CYP3A5*6, CYP3A4*1B and CYP3A4*1F alleles were identified in 20, 1, 4 and 2 subjects, respectively. No statistically significant differences were observed for the AUC_inf values between the different genotypes after the 75-µg or the 7.5-mg dose.Conclusion Presently, CYP3A4 and CYP3A5 genotyping methods do not sufficiently reflect the inter-individual variability of CYP3A activity.     

中药止咳橘红颗粒对CYP3A4和CYP1A2抑制作用的研究

目的：在人体内研究止咳橘红对CYP3A4和CYP1A2的抑制作用，以预测止咳橘红与常用临床药物的相互作用。方法：咪哒唑仑和咖啡因分别作为CYP3A4和A2的探针药物，采取交叉设计，10名受试者在服用3d止咳橘红的前后均服用7.5mg咪哒唑仑和100mg咖啡因，服药后采血测定两者及代谢产物的代谢动力学参数，探讨针药物及代谢物的浓度用HPLC-MS法测定，Cmax,tmax从药时曲线中直接读出，AUC用梯形法计算，Ke用3P87程序进行拟合计算，分析服药前后CYP3A4和CYP1A2被抑制的情况，结果 服用止咳橘红后，咪哒唑仑的代谢受到了轻微的抑制，它的血药浓度，达峰时间和药时曲线下面积都有了升高趋势，但无显著差异。而咖啡因的代谢未受到影响。结论 止咳橘红对CYP3A4的活性有较弱的抑制作用，能够导致CYP3A4底物咪哒唑仑代谢的轻微抑制，而对CYP1A2的活性没有影响。止咳橘红长期使用或超过治疗剂量使用时是否会对CYP3A4产生显著性影响。尚需进一步的研究证明。     

CYP3A5~*3和CYP3A4~*18B基因多态性对肾移植患者环孢素药代动力学的影响

目的回顾性研究肾脏移植后1mon,CYP3A5*3和CYP3A4*18B基因多态性对CsA药代动力学参数的影响。方法采用PCR-RFLP方法分析了63名肾脏移植患者CYP3A5*3和CYP3A4*18B基因型;荧光偏正免疫法用于检测肾移植患者静脉全血中的CsA浓度。结果在63名肾移植患者中,CYP3A5*3和CYP3A4*18B突变等位基因发生频率分别为0.770(95CI:0.767～0.773),0.235(95CI:0.235～0.241),而且这些等位基因表现出完全连锁不平衡。在移植术后1mon内,携带CYP3A4*1/*1野生型纯合子患者的C0以及剂量校正谷血浓度(C0/D)均明显高于携带CYP3A4*1/*18B杂合子或CYP3A4*18B/*18B突变型纯合子患者(P<0.05,Mann-WhitneyUtest);CYP3A5*1/*1基因型组的给药剂量明显高于CYP3A5*1/*3或CYP3A5*3/*3基因型组(P=0.004<0.01,Kruakal-Wallistest);CYP34*18B和CYP3A5*3联合考虑,对于CYP3A5表达组,同样发现C0、C0/D在CYP3A4*1/*1组C0以及C0/D均明显高于CYP3A4*1/*18B或CYP3A4*18B/*18B组(P<0.05,Mann-WhitneyUtest);而其他药动学参数在CYP3A5*3及CYP3A4*18B各组间相比差异则没有统计学意义。结论CYP3A5*3和(或)CYP3A4*18B基因多态性对肾移植后1monCsA药代动力学有一定影响,移植前CYP3A5*3基因型的分析仍需进一步研究。     

CYP3A4,CYP3A5和MDR1基因多态性对环孢素处置的影响

环孢素是一个广泛用于器官移植患者的免疫抑制剂,具有治疗指数窄,不同个体间药代动力学差异较大的特点。它主要通过肝脏和小肠的CYP3A4和CYP3A5代谢;同时它又是药物转运体的底物。不同个体间药物代谢酶和转运体活性的差异可能是造成不同器官移植患者环孢素药代动力学差异的主要原因。而遗传因素即编码药物代谢酶和转运体基因序列的差异可能是其产生活性差异的分子机制。因此,从编码药物代谢酶和转运体的基因入手,可能会为器官移植患者提供最优的治疗方案。     

候选新药对大鼠肝细胞色素P4503A4影响的研究

目的研究候选新药(HSH)对大鼠肝细胞色素P4503A4是否有抑制或诱导作用,以及这种作用是否具有性别差异。方法取大鼠雌雄各半,随机分为4个组:雄性对照组(Ⅰ)、雄性给药组(Ⅱ)、雌性对照组(Ⅲ)、雌性给药组(Ⅳ),均采用钙离子沉淀法制备肝微粒体。在各组肝微粒体中同时给予一定剂量的探针药物及目标药物,进行孵育,于不同时间点取样,测定该探针药物的剩余浓度并计算其体外半衰期。结果HSH对肝细胞色素P4503A4无影响。结论就大鼠而言,药物对肝细胞色素P4503A4无影响,HSH在同各种与CYP3A4代谢有关的药物合用时,相对安全。     

Development of template systems for ligand interactions of CYP3A5 and CYP3A7 and their distinctions from CYP3A4 template

Starting from established CYP3A4 Template (DMPK. 2019, and 2020), CYP3A5 and CYP3A7 Templates have been constructed to be reliable tools for verification of their distinct catalytic properties. A distinct occupancy was observed on CYP3A4-selective ligands, but not on the non-selective ligands, in simulation experiments. These ligands often invade into Bay-1 region during the migration from Entrance to Site of oxidation in simulation experiments. These results offered an idea of the distinct localization of Bay-1 residue on CYP3A5 Template, in which the Bay-1 residue stayed closely to Template border. The idea also accounted for the higher oxidation rates of CYP3A5, than of CYP3A4, of noscapine and schisantherin E through their enhanced sitting-stabilization. Typical CYP3A7 substrates such as zonisamide and retinoic acids took their placements without occupying a left side region of Template for their metabolisms. In turn, the occupancies of the left-side region were inevitably observed among poor ligands of CYP3A7. Altered extent of IJK-Interaction or localization of a specific residue at the left-side would thus explain distinct catalytic properties of CYP3A7 on Template. These data suggest the alteration of each one of Template region, from CYP3A4 Template, led to the distinct catalytic properties of CYP3A5 and CYP3A7 forms.     

重组肝CYP3A4与CYP3A29细胞微粒体药物代谢动力学比较

目的 比较巴马小型猪CYP3A29和人CYP3 A4稳定表达重组肝癌细胞株微粒体的药物代谢特征,在分子水平为巴马小型猪作为临床前药物代谢实验动物提供科学依据.方法 以CYP3A特异性代谢底物硝苯地平、睾酮及其抑制药酮康唑为探针药物,将探针药物与重组CYP3A4、CYP3A29细胞微粒体在优化的微粒体浓度、药物浓度、孵育时间等条件下进行体外孵育,高效液相色谱法检测其药物代谢(抑制)动力学参数,并将二者进行比较分析.结果 巴马小型猪CYP3A29与CYP3A4在硝苯地平和睾酮代谢差异无统计学意义(P＞0.05).酮康唑的抑制活性为:当代谢底物为硝苯地平时,酮康唑对CYP3A29和CYP3A4的半数抑制浓度分别为0.090,0.132 μmol·L-1(P＜0.05);当代谢底物为睾酮时,酮康唑对CYP3A29和CYP3A4的半数抑制浓度分别为0.056,0.032 μmol·L-1(P＜0.05).结论 重组CYP3A29与CYP3 A4细胞微粒体对硝苯地平和睾酮活性差异不显著;酮康唑对重组CYP3A29与CYP3A4细胞微粒体硝苯地平和睾酮代谢活性有差异.