MDRI的siRNA干扰口腔Tca8ll3/DDP细胞表达的研究

目的探讨小干扰RNA(small interfering RNA,si RNA)对口腔鳞癌多药耐药基因mdr1(MDRI)及其表达产物P-糖蛋白(permeability-glyco-protein,P-gp)的干扰作用。方法体外构建针对MDR1的小干扰RNA,将其转染至人舌癌耐药细胞系Tca8113/DDP,采用RT-PCR法检测转染前后MDR1 m RNA的表达;采用免疫细胞化学技术比较转染前后P-gp的表达;采用MTT法检测转染前后肿瘤耐药细胞对顺铂的敏感性。结果 Tca8113/DDP细胞经MDR1-si RNA转染后48 h的转染率达最高,为71.3%;转染后mdr1 m RNA表达较对照组显著降低,降低率为68.32%,转染48 h后P-gp的表达较对照组明显降低;si RNA可显著提高Tca8113/DDP细胞对DDP的敏感性,逆转其耐药性,耐药倍数为2.05。结论 si RNA可以明显干扰口腔鳞癌MDR1及相应蛋白P-gp的表达。     

外排型转运体介导的抗肿瘤药物多药耐药的研究进展

多药耐药（MDR）是指肿瘤细胞接触一种抗肿瘤药物后,也对其他多种结构不同、功能不同的抗肿瘤药物产生耐药性,其中外排型转运体所介导的MDR是其中至关重要的一部分。外排型转运体是指位于肿瘤细胞生物膜上的具有将抗肿瘤药物从细胞内外排到细胞外的转运体。已知的具有外排作用的转运体有P糖蛋白（P-gp）、多药耐药相关蛋白（MRP）、乳腺癌耐药蛋白（BCRP）和肺耐药蛋白（LRP）。综述这几种外排型转运体的一般性质并着重于阐述逆转这些转运体介导的多药耐药的药物及方法。     

金丝桃苷对小鼠S180肿瘤细胞获得性多药耐药相关因子表达的影响

目的:探讨金丝桃苷干预化疗诱导的肿瘤多药耐药(MDR)的分子机制,以指导临床应用金丝桃苷来逆转肿瘤多药耐药的产生.方法:建立小鼠S₁₈₀肿瘤细胞多药耐药模型,随机分为模型组、环磷酰胺(CTX)组、CTX+金丝桃苷组、金丝桃苷组,连续给药2周,观察各组瘤体大小,计算抑瘤率.流式细胞仪观察各组细胞凋亡率、P-糖蛋白(P-gp)、肺耐药相关蛋白(LRP)、凋亡促进因子Fas及抗凋亡因子bcl-2的表达.结果:CTX+金丝桃苷组抑瘤率、细胞凋亡率、Fas表达率均较CTX组显著增高,而P-gp、LRP、bcl-2表达率均较CTX组显著降低,差异均有统计学意义(P <0.01).结论:金丝桃苷有逆转小鼠S₁₈₀肿瘤获得性多药耐药的作用与降低P-gp、LRP、bcl-2表达,提高Fas表达有关.     

温下方逆转A549/DDP细胞的多药耐药及对膜表面蛋白表达的影响

目的运用血清药理学方法,体外研究温下方对A549/DDP细胞多药耐药的逆转作用及机制。方法正常血清及不同浓度的温下方含药血清作用于A549/DDP细胞,四甲基偶氮唑蓝(MTT)法检测温下方含药血清对A549/DDP细胞的逆转作用;运用免疫荧光技术,激光共聚焦显微镜及流式细胞仪检测肺耐药相关蛋白(LRP)、多药耐药相关蛋白(MRP)和P-糖蛋白(P-gp)的表达。结果温下方含药血清能明显逆转A549/DDP细胞的多药耐药,增敏倍数为2～2.5倍。并可明显降低P-gp、LRP、MRP蛋白表达。结论温下方通过降低P-gp、LRP、MRP的表达以增强A549/DDP对化疗药的敏感性,逆转肺腺癌细胞的多药耐药。     

ATP结合盒转运蛋白介导的MDR逆转剂的实验研究现况

多药耐药性(mu ltidrug resistance,MDR)是指人肿瘤细胞对结构各异的化疗药物产生交叉耐药,是肿瘤化疗失败的主要原因之一。为了增强肿瘤细胞对化疗药物的敏感性,积极寻求有效逆转MDR的药物已成为研究重点。体外被证实具有逆转耐药活性的化合物很多,但由于体内要达到体外逆转试验的有效浓度所需剂量过大,毒副作用大,因此限制了临床应用。ATP结合盒转运蛋白家族(ATP-b ind ing cassette,ABC)介导的药物外排机制是目前MDR的主要机制,ABC转运蛋白家族中与多药耐药性相关的转运蛋有P-糖蛋白(P-gp)、多药耐药相关蛋白(MRP)和乳腺癌耐药蛋白(BCRP)。本文对ABC转运蛋白介导的MDR逆转剂的研究进展做一综述。     

P糖蛋白介导的多药耐药及其逆转的研究进展

多药耐药(multidrug resistance,MDR)[1]是指肿瘤细胞对一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。MDR由多种途径诱导,可分为经典和非经典MDR两大机制。其中有P糖蛋白(P-gp)介导的MDR及其逆转是目前研究最为广泛和深入的课题之一。本文通过对近几年来有关P-gp介导的多药耐药及其逆转的研究进展的综合描述得出以下结论:通过化疗药物合用P-gp抑制剂、增加化疗药物脂溶性使药物迅速被吸收及调节信号通路抑制P-gp表达可以逆转肿瘤细胞的耐药性。1P-糖蛋白在人类基因组中,MDR基因含…     

骨肉瘤组织中P-qp及LRP的表达与临床病理特点关系的研究

目的 研究P-糖蛋白(P-gp)及肺耐药相关蛋白(LRP)在骨肉瘤(OS)中的表达及与临床病理特点的关系.方法 38例OS及10例正常骨组织的石蜡切片,以P-gp单克隆抗体C219及LRP单克隆抗体LRP56用SABC法进行免疫组化染色,并对有关临床及病理指标综合分析.结果 OS中P-gp及LRP阳性表达率分别为55.26%和42.11%,而正常骨组织均为阴性表达,两组间比较差异有显著意义(P＜0.05).此外,P-gp在转移组及外科分期较高组中的表达率高于未转移组及外科分期较低的病例组(P＜O.05);LRP在＜12岁或＞30岁年龄组中明显高于12～30岁病例组(P＜O.05).崧?1)P-gp与LRP均介导OS的多药耐药(MDR).(2)人OS对化疗不敏感、预后差与OS组织中存在P-gp及LRP有关.(3)P-gp与LRP的表达不相关,分别以独立机制介导OS的MDR.(4)用免疫组化法检测OS的P-gp和LRP,可作为临床常规筛选检测,并为指导制定合理的治疗方案和预后评估提供依据.     

纳米载体药物逆转P-gp介导的肿瘤多药耐药研究进展

纳米载药系统不但可提高抗肿瘤治疗的指数,而且有降低肿瘤耐药性的产生及逆转MDR的作用。因此,研究纳米载体药物用于逆转P-gp介导的肿瘤多药耐药具有广泛和重要的实际意义。     

纳米载药系统逆转肿瘤多药耐药的研究进展

目的:介绍纳米载药系统在逆转肿瘤多药耐药(MDR)方面的研究进展。方法:查阅近年来的相关文献,对纳米载体的特点,逆转MDR的机制及其在此领域的应用进行综述。结果:纳米技术可以使药物通过主动或被动靶向作用,更多地被肿瘤细胞摄取而逆转MDR。纳米载药系统还可以作为RNA的载体,通过基因干扰技术逆转肿瘤的MDR。结论:与单一功能和组成的载药系统相比,多功能或药物联用的纳米载药系统在逆转MDR方面更具优势。     

雷公藤甲素对肺癌A549/DDP细胞多药耐药的逆转作用及机制

目的：探讨雷公藤甲素对肺癌A549/DDP多药耐药的逆转作用及机制。方法：雷公藤甲素作用于肺癌A549/DDP细胞后,应用MTS法检测细胞生长抑制率,流式细胞术检测细胞内罗丹明-123（Rhodamine-123,Rh-123）及细胞表面P-糖蛋白（P-glycoprotein,P-gp）表达,应用Western blot法和real time PCR检测肿瘤细胞多药耐药蛋白 （MDR1）和肺耐药相关蛋白（LRP）表达变化,应用报告基因技术检测细胞NF-κB启动子活性,应用Western blot法检测肿瘤细胞Akt磷酸化。结果：雷公藤甲素可提高肺癌A549/DDP细胞药物敏感性,经2μM和10μM雷公藤甲素作用后,顺铂逆转倍数（RF）分别为2.09倍和2.93倍,肿瘤细胞中Rh-123含量分别提高了1.38倍和2.88倍,P-gp表达分别是对照组的57.1%和32.1%,MDR1和LRP蛋白表达水平显著下降,MDR1 mRNA表达分别是对照组的64.2%和22.6%,LRP mRNA表达分别是对照组的54.8%和34.7%, NF-κB启动子活性分别是对照组的55.6%和23.6%,Akt磷酸化水平显著下降。结论：雷公藤甲素可逆转肺癌A549/DDP细胞多药耐药性,提高肿瘤细胞药物敏感性,抑制药物外排,降低细胞MDR1和LRP表达,其机制可能与抑制Akt磷酸化水平,下调NF-κB启动子活性有关。     

Mitochondrial localization and activity of P-glycoprotein in doxorubicin-resistant K562 cells

It is now well-established that P-glycoprotein 170 (P-gp), an efflux pump involved in multidrug resistance (MDR) is overexpressed at the plasma membrane of doxorubicin-resistant K562 leukemia cells. Nevertheless, several results suggested: (i) that P-gp-mediated drug efflux was not the only mechanism involved in resistance; (ii) that intracellular compartments could accumulate the drug, preventing it from reaching its nuclear targets; (iii) that agents able to reverse multidrug resistance may lead to intracellular drug redistribution. We have studied the localization of P-gp in mitochondria as well as its functional properties in this compartment. Using several monoclonal antibodies (MoAbs) directed against different P-gp epitopes, a protein was detected in the cytoplasm of two doxorubicin-resistant K562 sublines and, by confocal laser scanning microscopy, this protein was shown to co-localize in the Golgi apparatus and in mitochondria, in equivalent proportions. Purified mitochondria were isolated from K562 cell variants; the presence of a protein of about 170 kDa and reacting with several anti-P-gp antibodies was assessed in MDR cells by Western blotting and flow cytometry. Functional assays have shown that mitochondrial P-gp was involved in doxorubicin accumulation inside the organelle but not in its efflux, suggesting an orientation of P-gp in the mitochondrial membrane inverse to that observed in the plasma membrane. A potential role for mitochondrial P-gp in MDR cells would be to protect the nucleus from doxorubicin. This is the first demonstration of the presence and functional activity of P-gp in mitochondria of MDR cells.     

多药耐药基因在大肠癌组织中的表达和临床研究

目的探讨大肠癌组织中7种多药耐药因子的表达、共表达及与患者临床病理特征的相关性。方法采用微波EnVision免疫组织化学法联合检测63例大肠癌患者癌组织中P-糖蛋白(P-gp)、谷胱甘肽-S转移酶-π(GST-π)、DNA拓扑异构酶(TopoⅡ)、胸苷酸合成酶(TS)、甲基鸟嘌呤甲基转移酶(MGMT)、肺耐药蛋白(LRP)及多药耐药相关蛋白(MRP)的表达水平。结果P-gp、GST-π、TopoⅡ、TS、MGMT、LRP和MRP在大肠癌组织中的阳性表达率分别为54%(34例)、71%(34例)、62%(39例)、67%(42例)、57%(36例)、79%(50例)和30%(19例)。所有的多药耐药因子表达均与患者的年龄、性别无相关。MGMT、LRP的表达与淋巴结转移相关;P-gp、GST-π、TopoⅡ、MRP的表达与组织学分级相关;TS、MGMT、LRP的表达与临床分期相关;P-gp、MGMT的表达与生存期明显相关。结论大肠癌组织表达多种耐药因子,各耐药因子间共表达具有明显相关性。大肠癌耐药由多种耐药基因共同参与,联合检测多项耐药因子有重要的临床意义。     

Establishment and characterization of adriamycin-resistant human colorectal adenocarcinoma HCT-15 cell lines with multidrug resistance

The multidrug resistance (MDR) phenotype, either intrinsic and/or acquired, is discussed in relation to several MDR-associated markers such as P-glycoprotein (P-gp) encoded by mdr1, multidrug-resistance-associated protein (MRP) encoded by MRP and lung-resistance-associated protein (LRP) encoded by LRP. Well-characterized in vitro models are required to elucidate the mechanisms of MDR. The aim of the present study is the establishment of a drug-resistant subline from human colorectal adenocarcinoma HCT-15 that intrinsically expresses moderate levels of P-gp, MRP and LRP. Three adriamycin-resistant sublines (HCT-15/ADM1, HCT-15/ADM2 and HCT-15/ADM2-2) were established by stepwise exposure in growth medium that was supplemented with 25-200 ng/ml adriamycin-resulting in a 2.2- to 7.8-fold increase in IC(50) values by using the XTT assay. They were cross-resistant to MDR-related drugs, epirubicin, mitoxantrone, vincristine, etoposide and taxol, but not the MDR-unrelated drug, mytomycin C. The resistance to adriamycin was confirmed in vivo by a lack of sensitivity in athymic nude mice. Gene expression data for mdr1/P-gp, MRP/MRP and LRP/LRP on both mRNA and protein levels demonstrated that the molecules contributing to MDR in resistant sublines are mainly P-gp and partially MRP. The newly established adriamycin-resistant sublines of HCT-15 will provide clinically relevant tools to investigate how to overcome drug resistance and elucidate possible mechanisms of acquired MDR in human colon cancer.     

姜黄素衍生物C15对白血病K562/A02细胞多药耐药的逆转作用

目的: 探讨姜黄素衍生物C15对人白血病K562/A02细胞多药耐药(multidrug resistance,MOR)的逆转作用及其作用机制。方法: 四甲基偶氮唑蓝(MTT)法检测细胞增殖;流式细胞术检测P-糖蛋白(P-gp)外排泵功能和细胞周期;免疫印迹法检测蛋白表达;P-gp-Glo^TM Assay System试剂盒检测P-gp ATP水解酶(ATPase)活性。结果: C15对K562/A02细胞半数抑制浓度(IC₅₀)大于50 μmol·L^-1。对K562/A02细胞无明显细胞毒的浓度为2.5,5.0,10.0 μmol·L^-1的C15逆转对K562/A02细胞对阿霉素(ADR)耐药的倍数分别为2.60,5.39,11.39,对长春新碱(vincristine, VCR)耐药的倍数分别为4.50,18.07,124.35,但是对非P-gp底物的化疗药物顺铂(cisplatin, CIS)和敏感细胞K562基本无逆转效果。2.5,5.0,10.0 μmol·L^-1 C15可以增加耐药细胞K562/A02胞内罗丹明123(Rh-123)的蓄积量分别为1.93,2.30,2.47倍。C15增加阿霉素(adriamycin, ADR)在K562/A02细胞中的蓄积水平,降低P-gp介导的Rh-123外排速率。2.5,10.0 μmol·L^-1 C15与300 nmol·L^-1VCR联合作用后,可使K562/A02细胞的G2/M期比例从9.36%增加到67.57%和69.38%。C15对P-gp蛋白和ATPase的活性没有抑制作用。结论: C15可能是P-gp的非衣物型抑制剂,且具有逆转K562/A02细胞MDR的作用,该作用与其抑制细胞P-gp的外排泵功能有关。     

Increase in doxorubicin cytotoxicity by inhibition of P-glycoprotein activity with lomerizine

Acquired resistance to chemotherapy is a major problem during cancer treatment. One mechanism for drug resistance is overexpression of the MDR (multidrug resistance)1 gene encoding the transmembrane efflux pump, P-glycoprotein (P-gp). Calcium channel blockers such as verapamil, nifedipine and nicardipine have been shown to reverse cellular drug resistance by inhibiting P-gp drug efflux. This study evaluated whether a new calcium channel blocker, lomerizine, influenced doxorubicin (Dox) cytotoxicity and P-gp activity in a P-gp-expressing cell line compared to a non-expressing subline. Verapamil, and even more markedly, lomerizine, increased cellular uptake of calcein transported by P-gp in a P-gp-expressing erythroleukemia cell line, K562-Dox. Ten microM of lomerizine reduced the IC50 of doxorubicin in the K562-Dox from 60000 ng/ml to 800 ng/ml, whereas the IC50 of doxorubicin in the K562 subline was only marginally affected by these drugs. Lomerizine showed greater reduction in P-gp efflux than verapamil at an equimolar concentration. These results suggest that lomerizine has the clinical potential to reverse tumor MDR involving the efflux protein P-gp.     

肺癌组织及外周血多药耐药基因相关蛋白的表达及其相关性研究

目的 检测多药耐药相关蛋白(MRP)和肺耐药蛋白(LRP)在肺癌组织及外周血中的表达及其相关性,探讨其临床意义.方法 采用逆转录一聚合酶链反应(RT-PCR)检测47例患者肺癌组织及外周血的MRP、LRP mRNA的表达水平.结果 肺癌组织及外周血,MRP mRNA的阳性表达率分别为74.5％(35/47)和70.2％...     

P糖蛋白与细胞凋亡及肿瘤多药耐药的关系

综述P糖蛋白与细胞凋亡及肿瘤多药耐药的内在联系及其可能机制。许多抗肿瘤药物可通过诱导细胞凋亡，杀伤肿瘤细胞，而细胞膜上P糖蛋白具有多重生理功能，可通过其药物外排功能和直接或间接参与细胞凋亡的调控，导致多药耐药性的产生。