非小细胞肺癌组织ABCC10的表达及其与耐药相关性的研究

目的:检测ABCC10在非小细胞肺癌(NSCLC)组织中的表达,探讨其与组织学类型、分级和TNM分期的关系,检测相应癌组织对化疗药物的敏感性.方法:采用免疫组化EnVinsion法检测ABCC10在75例NSCLC组织中的表达,进行统计学分析.采用MTT法检测相应癌组织对化疗药物的敏感性,分析其与ABCC10表达的相关性.结果:ABCC10主要定位于胞膜上和胞质中.鳞癌、腺癌阳性率分别为77.5%和85.7%,两者差异有统计学意义,P=0.007.鳞癌、腺癌不同病理分级、TNM分期间ABCC10表达差异均有统计学意义(P=0.000、0.003、0.009和0.032).NSCLC组织的耐药性试验结果与其相应组织中ABCC10的表达做相关性检验,多西他赛、紫杉醇、长春瑞滨、长春新碱、顺铂差异有统计学意义(P=0.000),相关系数分别为0.674、0.633、0.610、0.565和0.532.结论:ABCC10在NSCLC组织中高表达,其中腺癌表达高于鳞癌,表达的高低与组织学类型、分级,TNM分期有关,很可能与NSCLC化疗药物耐药有关.     

非小细胞肺癌中SLC22A18的表达及其临床意义

背景与目的已有的研究证明:多药耐药(multidrug resistance,MDR)是肺癌化疗失败的主要原因,研究MDR的产生机制对于提高肺癌的化疗疗效有着重要的临床意义。SLC22A18基因编码蛋白与跨膜转运体相似,影响药物敏感性、细胞代谢和生长,可能在肺癌MDR的产生中发挥一定作用。本研究旨在检测SLC22A18在非小细胞肺癌(non-small cell lung cancer,NSCLC)及相应正常组织中的表达,并分析其与组织学类型、分级和TNM分期的关系。方法应用免疫组化EnVinsion法检测SLC22A18在96例NSCLC及正常组织中的表达,结果用统计学软件SPSS17.0进行分析。结果 SLC22A18主要定位于胞膜和胞质中。SLC22A18在NSCLC中的表达高于正常组织,差异明显(P<0.01),鳞癌、腺癌阳性率分别为68.0%和78.2%,差异性有统计学意义(P<0.05)。鳞癌、腺癌不同病理分级、TNM分期间SLC22A18表达差异性均有统计学意义,癌组织分化越差、分期越晚,SLC22A18表达越高(P<0.05)。结论 SLC22A18在NSCLC组织中高表达,表达的高低与组织学类型、分级、TNM分期有关,本研究为进一步探讨SLC22A18在肿瘤中的表达及可能的耐药作用提供了实验依据。     

非小细胞肺癌患者MDR1、FLK-1和LRP的表达及其临床意义

目的:研究多药耐药基因(MDR1)、血管内皮生长因子受体(Flk-1)、肺耐药蛋白(LRP)基因在非小细胞肺癌(NSCLC)中的表达及其临床意义.方法:用免组化技术(ABC法)对38例术前未进行化疗及放疗的NSCLC组织中MDR1、Flk-1、LRP表达进行检测.结果:在38例非小细胞肺癌组织中,MDR1、Flk-1、LRP基因阳性表达率分别为42.1%(16/38)、57.9%(22/38)和44.7%(17/38),其共同表达率(MDR1+LRP)为13(34.2%),(Flk-1+LRP)为12(31.6%),(Flk-1+MDR1+LRP)为10(26.3%);MDR1蛋白阳性的肺癌患者出现肺门淋巴结转移率较高,与TNM分期和有无淋巴结转移等各项病理因素无明显相关(P>0.05);LRP的表达与肺癌的组织学类型有关,腺癌中LRP的表达明显高于鳞癌(P<0.05),高分化高表达,而与TNM分期、有无淋巴结转移无明显相关(P>0.05);Flk-1与TNM分期相关,(P<0.05),Flk-1、LRP蛋白表达阳性的肺癌患者出现肺门淋巴结转移率较高,但无统计学意义(P>0.05);MDR1+LRP、Flk-1+LRP和Flk-1+MDR1+LRP基因的表达率在NSCLC的不同病理类型及组织分化程度的表达差异无统计学意义(P>0.05);MDR1+LRP、复发与患者的预后有关(P<0.05).结论:MDR1、FLK-l和LRP基因蛋白产物的检测对肺癌患者的诊治和预后评估有积极意义.     

ABCG2与空泡型ATP酶在非小细胞肺癌中的表达及其相关性

目的分析ABCG2和空泡型ATP酶（V—ATPase）在非小细胞肺癌（NSCLC）病理分类、TNM分期、病理分级中表达的差异性以及相关性。方法对92例NSCLC组织样本采用免疫组织化学EnVision法检测ABCG2和V—ATPase的表达。结果ABCG2、V—ATPase在腺癌和鳞癌中有表达,差异有统计学意义（P=0．003、P=0．000）。ABCG2在腺癌TNM分期中的表达差异有统计学意义（P=0．004）,在鳞癌TNM分期中差异无统计学意义;在腺癌和鳞癌病理分级的表达差异有统计学意义（P=0．028、P=0．000）。V—ATPase在腺癌TNM分期、鳞癌病理分级间的表达差异有统计学意义（P=0．026、P=0．002）,在鳞癌的TNM分期、腺癌病理分级组间的表达差异无统计学意义。在总体样本及腺癌、鳞癌中ABCG2和V—ATPase的表达有相关性。结论V—ATPase可能与ABCG2共同参与NSCLC的多药耐药机制。     

肺癌患者FLK-1、LRP和MDR1的表达与临床研究

目的:探讨血管内皮生长因子受体 (Flk 1),肺耐药蛋白 (LRP)基因以及多药耐药基因 (MDR1)蛋白与肺癌患者临床及病理指标的关系。方法:用免疫组化技术(ABC法)对原发性肺癌组织中三种基因的表达进行检测。结果: 70例肺癌中,非小细胞肺癌MDR1阳性率 49. 2% (29 /59),明显高于小细胞肺癌 (SCLC) 18. 2% (2 /11)(P<0. 05);非小细胞肺癌LRP阳性率 69. 5% (41 /59),明显高于小细胞肺癌 27. 3% (3 /11) (P<0. 05)。腺癌中MDR1与LRP的表达明显高于鳞癌(P<0. 05)。LRP与Flk 1在NSCLCs中共同表达 49. 2% (29 /59),LRP的表达与肺癌的组织学分级相关,MDR1和LRP的表达与肺癌的组织学类型有关,Flk 1与TNM分期相关,均有统计学意义(P<0. 05)。Flk 1 LRP均阳性、FLK 1 LRP MDR1均阳性、中药治疗、复发与患者的生存率有关(P<0. 05)。结论:FLK 1、LRP和MDR1基因蛋白产物的检测对肺癌患者的诊治和预后评估有积极意义。     

ABCG4和V-ATPase在非小细胞肺癌中的表达及相关性临床意义

背景与目的多药耐药是肺癌化疗治疗失败的重要原因,ABC介导药物外排是耐药的主要因素,寻找该家族中新的耐药蛋白并阐明其耐药机制十分重要。ABCG4有望成为耐药候选基因;耐药性与细胞内外pH值可能有关,而V-ATPase在调节pH值起主要作用。本研究通过检测ABCG4和V-ATPase在非小细胞肺癌中的表达,分析其与病理分级和TNM分期间的关系以及两蛋白表达的相关性,为研究ABCG4、V-ATPase在肿瘤表达及耐药相关性提供基础。方法采用免疫组化EnVinsion法、免疫荧光法检测在肺鳞癌、腺癌中的表达,激光共聚焦显微镜观察其定位和共定位,用统计学分析表达差异性和相关性。结果ABCG4在肺鳞癌、腺癌中高表达,两者差异性显著(P=0.001);鳞癌Ⅱ和Ⅱ-Ⅲ组间、腺癌不同分化组间差异性显著;鳞癌和腺癌TNM分期秩和检验差异性显著。V-ATPase在鳞癌、腺癌中也为高表达,两者差异性非常显著;鳞癌Ⅱ和Ⅱ-Ⅲ组间、腺癌不同分化组间差异性显著;在鳞癌和腺癌TNM分期秩和检验差异性均不显著。ABCG4和V-ATPase蛋白在鳞癌、腺癌、鳞癌Ⅱ和Ⅱ-Ⅲ、中分化腺癌各组中的表达相关性检验P<0.01,相关系数rs分别为0.771、0.765、0.714、0.777、0.865;而低分化腺癌组中的相关性检验P值为0.048,相关系数rs为0.350。ABCG4主要定位在胞膜上和胞质中,两蛋白有共定位现象。结论ABCG4和V-ATPase在非小细胞肺癌中高表达,表达的高低与病理分级、TNM分期有关;两蛋白在鳞癌、腺癌及其分级间表达都存在相关性,可能存在相互作用的现象。这为研究ABCG4和V-ATPase在肿瘤中的表达及可能耐药作用提供了实验依据。     

NOK与FGFR2在非小细胞肺癌中的表达及临床意义

目的 检测含激酶结构域新原癌基因（NOK）与成纤维细胞生长因子受体2（FGFR2）在非小细胞肺癌（NSCLC）中的表达,分析其在不同病理类型、病理分级及临床TNM分期之间的表达差异及相关性。方法 应用免疫组化En Vision法检测NOK与FGFR2在163例NSCLC组织中的表达,分析其表达与病理类型、临床TNM分期、病理分级之间的关系,以及NOK与FGFR2表达的相关性。结果 NOK、FGFR2在163例NSCLC组织中的阳性表达率分别为66.7％和85.2％。NOK在肺鳞癌和肺腺癌中的阳性表达率分别为64.5％和72.6％,差异无统计学意义（P＞0.05）;NOK在不同TNM分期之间及在不同病理分级之间的表达差异均有统计学意义（P=0.000）。FGFR2在肺鳞癌和肺腺癌中的阳性表达率分别为88.6％和85.7％,差异无统计学意义（P＞0.05）;FGFR2在不同TNM分期之间及在不同病理分级之间的表达差异均有统计学意义（P＜0.05）。NOK与FGFR2蛋白表达在NSCLC（r=0.640,P=0.000）、肺鳞癌（r=0.684,P=0.000）、肺腺癌（r=0.597,P=0.000）组织中均呈正相关。结论NOK与FGFR2在NSCLC中高表达,其表达与病理类型、病理分级及TNM分期有关,提示二者可能与NSCLC的发生和发展有关。     

ABCG4种V-ATPase在非小细胞肺癌中的表达及相关性临床意义

背景与目的 多药耐药是肺癌化疗治疗失败的重要原因.ABC介导药物外排是耐药的主要因素,寻找该家族中新的耐药蛋白并阐明其耐药机制十分重要.ABCG4有望成为耐药候选基因;耐药性与细胞内外pH值可能有关,而V-ATPase在调节pH值起主要作用.本研究通过检测ABCG4和V-ATPase在非小细胞肺癌中的表达,分析其与病理分级和TNM分期间的关系以及两蛋白表达的相关性,为研究ABCG4、V-ATPase在肿瘤表达及耐药相关性提供基础.方法 采用免疫组化EnVinsion法、免疫荧光法检测在肺鳞癌、腺癌中的表达,激光共聚焦显微镜观察其定位和共定位,用统计学分析表达差异性和相关性.结果 ABCG4在肺鳞癌、腺癌中高表达,两者差异性显著(P=0.001);鳞癌Ⅱ和Ⅱ-Ⅲ组间、腺癌不同分化组间差异性显著;鳞癌和腺癌TNM分期秩和检验差异性显著.V-ATPase在鳞癌、腺癌中也为高表达,两者差异性非常显著;鳞癌Ⅱ和Ⅱ-Ⅲ组间、腺癌不同分化组间差异性显著;在鳞癌和腺癌TNM分期秩和检验差异性均不显著.ABCG4和V-ATPase蛋自在鳞癌、腺癌、鳞癌Ⅱ和Ⅱ-Ⅲ、中分化腺癌各组中的表达相关性检验P<0.01.相关系数rs分别为0.771、0.765、0.714、0.777、0.865;而低分化腺癌组中的相关性检验p值为0.048,相关系数rs为0.350.ABCG4主要定位在胞膜上和胞质中,两蛋白有共定位现象.结论 ABCG4和V-ATPase在非小细胞肺癌中高表达.表达的高低与病理分级、TNM分期有关;两蛋白在鳞癌、腺癌及其分级间表达都存在相关性,可能存在相互作用的现象.这为研究ABCG4和V-ATPase在肿瘤中的表达及可能耐药作用提供了实验依据.     

Stat5与CyclinB1在非小细胞肺癌组织中的表达及相关性

目的 探讨信号转导与转录激活因子5(Stats)与细胞周期素CyclinB1在非小细胞肺癌和正常肺组织中的表达及关系,进一步探讨Stat5、CyclinB1与非小细胞肺癌发生发展的关系.方法 利用SABC免疫组织化学技术检测35例非小细胞肺癌(NSCLC)组织及10例肺正常组织中Stat5和CyclinB1的表达.结果 Stats、CyclinB1在非小细胞肺癌组织中的表达水平明显高于肺正常组织(P<0.01).Stat5蛋白和CyclinB1蛋白在NSCLC组织中的表达与患者的性别、年龄、组织分化程度无关.Stat5蛋白与组织学类型有关,在腺癌组织中的表达强度明显高于鳞癌,差异有统计学意义(P<0.01).CyclinB1蛋白与TNM分期有关,在Ⅲ、Ⅳ期癌组织中的表达强度明显高于Ⅰ、Ⅱ期,差异有统计学意义(P<0.05).Stat5与CyclinB1的表达呈显著相关性(P<0.01).结论 Stat5、CyclinB1可能在肺癌的发生发展中发挥重要作用,CyclinB1的表达可能由Stat5调控.     

多聚免疫球蛋白受体(pIgR/SC)在肺癌组织的表达及其临床意义

背景与目的:探讨多聚免疫球蛋白受体(polymeric immunoglobulin receptor/secretory component,pIgR/SC)在肺癌组织中的表达情况及其临床意义.材料与方法:采用大样本石蜡包埋组织(包含344例肺鳞癌、93例肺腺癌、47例小细胞肺癌以及30例同组患者的正常肺组织)构建的组织微阵列,进行免疫组织化学(SP法)染色,分析pIgR/SC蛋白表达情况及其与肺癌临床分期和病理分级间的关系.结果:pIgR/SC蛋白在肿瘤组织(尤其是非小细胞肺癌)中的表达水平(54.1%)显著高于正常对照组织(6.7%),其差异具有统计学意义(P＜0.001);在肺癌组织不同病理类型之间的差异具有统计学意义(P＜0.001),其表达的阳性率从高到低依次为:鳞癌66.3%＞腺癌34.4%＞小细胞肺癌4.3%.而pIgR/SC蛋白表达水平在肺癌的临床分期和组织分级间的差异均无统计学意义(P＞0.05).结论:pIgR/SC蛋白的异常表达反应了肺癌细胞组织学来源的差异,其过表达可能出现在肺癌(尤其是鳞癌)发生发展的早期阶段.     

Recent advances regarding the role of ABC subfamily C member 10 （ABCCIO） in the efflux of antitumor drugs

ABCC10, also known as multidrug-resistant protein 7 （MRP7）, is the tenth member of the C subfamily of the ATP-binding cassette （ABC） superfamily. ABCC10 mediates multidrug resistance （MDR） in cancer cells by preventing the intracellular accumulation of certain antitumor drugs. The ABCC10 transporter is a 171-kDa protein that is localized on the basolateral cell membrane. ABCC10 is a broad-specificity transporter of xenobiotics, including antitumor drugs, such as taxanes, epothilone B, vinca alkaloids, and cytarabine, as well as modulators of the estrogen pathway, such as tamoxifen. In recent years, ABCC10 inhibitors, including cepharanthine, lapatinib, erlotinib, nilotinib, imatinib, sildenafil, and vardenafil, have been reported to overcome ABCC10-mediated MDR. This review discusses some recent and clinically relevant aspects of the ABCC10 drug efflux transporter from the perspective of current chemotherapy, particularly its inhibition by tyrosine kinase inhibitors and phosphodiesterase type 5 inhibitors.     

Expression and promoter methylation analysis of ATP-binding cassette genes in pancreatic cancer

We investigated the relationship of ABCB1/MDR1, ABCC1/MRP1 and ABCG2/BCRP expression and promoter methylation with pancreatic cancer tumorigenesis and drug resistance. Gemcitabine-resistant pancreatic cancer cells, SW1990/GZ (33.3-fold increased resistance), were obtained by treating SW1990 cells with gemcitabine. The expression of ABCB1/MDR1, ABCC1/MRP1 and ABCG2/BCRP was determined by quantitative real-time RT-PCR in the cell lines, 3 normal pancreatic tissues, 15 human pancreatic cancer samples and 15 adjacent tissues. Promoter methylation was determined in cell lines by bisulfite genomic sequencing. ABCB1/MDR1, ABCC1/MRP1 and ABCG2/BCRP were upregulated in SW1990 and SW1990/GZ compared with normal pancreatic tissue, and expression in SW1990/GZ was significantly higher than in SW1990 cells. ABCB1/MDR1, ABCC1/MRP1 and ABCG2/BCRP were upregulated in pancreatic cancer tissues, compared to adjacent tissues. The ABCB1/MDR1, ABCC1/MRP1 and ABCG2/BCRP promoter were hypomethylated in all the cell lines. ABCB1/MDR1, ABCC1/MRP1 and ABCG2/BCRP expression correlated with pancreatic cancer tumorigenesis and drug resistance in a mechanism that is independent of promoter methylation.     

药物转运蛋白和多药耐药性的研究进展

多药耐药性(MDR)是肿瘤化疗失败的最常见原因，药物转运蛋白在肿瘤多药耐药性中产生了重要的作用。这些属于ATP结合盒式转运蛋白的药泵激活导致药物经由细胞膜外排，ABC转运蛋白3个亚家族涉及到细胞毒性药物的转运，这些转运蛋白包括ABCB亚家族、ABCC亚家族和ABCG亚家族。本文就几年来在药物转运蛋白与MDR方面的研究进展作一综述。     

A molecular understanding of ATP-dependent solute transport by multidrug resistance-associated protein MRP1

Over a million new cases of cancers are diagnosed each year in the United States and over half of these patients die from these devastating diseases. Thus, cancers cause a major public health problem in the United States and worldwide. Chemotherapy remains the principal mode to treat many metastatic cancers. However, occurrence of cellular multidrug resistance (MDR) prevents efficient killing of cancer cells, leading to chemotherapeutic treatment failure. Numerous mechanisms of MDR exist in cancer cells, such as intrinsic or acquired MDR. Overexpression of ATP-binding cassette (ABC) drug transporters, such as P-glycoprotein (P-gp or ABCB1), breast cancer resistance protein (BCRP or ABCG2) and/or multidrug resistance-associated protein (MRP1 or ABCC1), confers an acquired MDR due to their capabilities of transporting a broad range of chemically diverse anticancer drugs. In addition to their roles in MDR, there is substantial evidence suggesting that these drug transporters have functions in tissue defense. Basically, these drug transporters are expressed in tissues important for absorption, such as in lung and gut, and for metabolism and elimination, such as in liver and kidney. In addition, these drug transporters play an important role in maintaining the barrier function of many tissues including blood-brain barrier, blood-cerebral spinal fluid barrier, blood-testis barrier and the maternal-fetal barrier. Thus, these ATP-dependent drug transporters play an important role in the absorption, disposition and elimination of the structurally diverse array of the endobiotics and xenobiotics. In this review, the molecular mechanism of ATP-dependent solute transport by MRP1 will be addressed.     

Binding and inhibition of drug transport proteins by heparin: A potential drug transporter modulator capable of reducing multidrug resistance in human cancer cells

A major problem in cancer treatment is the development of resistance to chemotherapeutic agents, multidrug resistance (MDR), associated with increased activity of transmembrane drug transporter proteins which impair cytotoxic treatment by rapidly removing the drugs from the targeted cells. Previously, it has been shown that heparin treatment of cancer patients undergoing chemotherapy increases survival. In order to determine whether heparin is capable reducing MDR and increasing the potency of chemotherapeutic drugs, the cytoxicity of a number of agents toward four cancer cell lines (a human enriched breast cancer stem cell line, two human breast cancer cell lines, MCF-7 and MDA-MB-231, and a human lung cancer cell line A549) was tested in the presence or absence of heparin. Results demonstrated that heparin increased the cytotoxicity of a range of chemotherapeutic agents. This effect was associated with the ability of heparin to bind to several of the drug transport proteins of the ABC and non ABC transporter systems. Among the ABC system, heparin treatment caused significant inhibition of the ATPase activity of ABCG2 and ABCC1, and of the efflux function observed as enhanced intracellular accumulation of specific substrates. Doxorubicin cytoxicity, which was enhanced by heparin treatment of MCF-7 cells, was found to be under the control of one of the major non-ABC transporter proteins, lung resistance protein (LRP). LRP was also shown to be a heparin-binding protein. These findings indicate that heparin has a potential role in the clinic as a drug transporter modulator to reduce multidrug resistance in cancer patients.     

UMMS-4 enhanced sensitivity of chemotherapeutic agents to ABCB1-overexpressing cells via inhibiting function of ABCB1 transporter

Multidrug resistance (MDR) mediated by ATP-binding cassette (ABC) transporters through efflux of antineoplastic agents from cancer cells is a major obstacle to successful cancer chemotherapy. The inhibition of these ABC transporters is thus a logical approach to circumvent MDR. There has been intensive research effort to design and develop novel inhibitors for the ABC transporters to achieve this goal. In the present study, we evaluated the ability of UMMS-4 to modulate P-glycoprotein (P-gp/ABCB1)-, breast cancer resistance protein (BCRP/ABCG2)- and multidrug resistance protein (MRP1/ABCC1)-mediated MDR in cancer cells. Our findings showed that UMMS-4, at non-cytotoxic concentrations, apparently circumvents resistance to ABCB1 substrate anticancer drugs in ABCB1-overexpressing cells. When used at a concentration of 20 μmol/L, UMMS-4 produced a 17.53-fold reversal of MDR, but showed no effect on the sensitivity of drug-sensitive parental cells. UMMS-4, however, did not significantly alter the sensitivity of non-ABCB1 substrates in all cells and was unable to reverse ABCG2- and ABCC1-mediated MDR. Additionally, UMMS-4 profoundly inhibited the transport of rhodamine 123 (Rho 123) and doxorubicin (Dox) by the ABCB1 transporter. Furthermore, UMMS-4 did not alter the expression of ABCB1 at the mRNA and protein levels. In addition, the results of ATPase assays showed that UMMS-4 stimulated the ATPase activity of ABCB1. Taken together, we conclude that UMMS-4 antagonizes ABCB1-mediated MDR in cancer cells through direct inhibition of the drug efflux function of ABCB1. These findings may be useful for the development of safer and more effective MDR modulator.     

Cetuximab enhanced the efficacy of chemotherapeutic agent in ABCB1/P-glycoprotein-overexpressing cancer cells

The overexpression of ATP-binding cassette (ABC) transporters is closely associated with the development of multidrug resistance (MDR) in certain types of cancer, which represents a formidable obstacle to the successful cancer chemotherapy. Here, we investigated that cetuximab, an EGFR monoclonal antibody, reversed the chemoresistance mediated by ABCB1, ABCG2 or ABCC1. Our results showed that cetuximab significantly enhanced the cytotoxicity of ABCB1 substrate agent in ABCB1-overexpressing MDR cells but had no effect in their parental drug sensitive cells and ABCC1, ABCG2 overexpressing cells. Furthermore, cetuximab markedly increased intracellular accumulation of doxorubicin (DOX) and rhodamine 123 (Rho 123) in ABCB1-overexpressing MDR cancer cells in a concentration-dependent manner. Cetuximab stimulated the ATPase activity but did not alter the expression level of ABCB1 or block phosphorylation of AKT and ERK. Interestingly, cetuximab decreased the cell membrane fluidity which was known to decrease the function of ABCB1. Our findings advocate further clinical investigation of combination chemotherapy of cetuximab and conventional chemotherapeutic drugs in ABCB1 overexpressing cancer patients.     

外源MDR-1基因对小鼠肺腺癌细胞耐药性产生的影响及机理研究

目的 了解ＭＤＲ－１基因表达中细胞药性的关系。方法 用ＦＵＧＥＮ＾ＴＭ６转染试剂将ＭＤＲ－１基因导入小鼠Ｌｅｗｉｓ肺腺癌细胞株（３ＬＬ）,建立池耐药细胞株（３ＬＬ－ＭＤＲ－１）．用ＭＴＴ方法测定和划搏定对药的逆转效应,ＭＤＲ－１基因表达产物ｐ－ｇｐ采用免疫组化方法观察,应用流式细胞仪分析其对示踪剂罗丹明１２３的摄取与排泄。结果 建立了一株能稳定表达ｐ－ｇｐ和对长春生物碱类、鬼白纱类具有显著耐药性的     

Celastraceae sesquiterpenes as a new class of modulators that bind specifically to human P-glycoprotein and reverse cellular multidrug resistance

Overexpression of ABCB1 (MDR1) P-glycoprotein, a multidrug efflux pump, is one mechanism by which tumor cells may develop multidrug resistance (MDR), preventing the successful chemotherapeutic treatment of cancer. Sesquiterpenes from Celastraceae family are natural compounds shown previously to reverse MDR in several human cancer cell lines and Leishmania strains. However, their molecular mechanism of reversion has not been characterized. In the present work, we have studied the ability of 28 dihydro-beta-agarofuran sesquiterpenes to reverse the P-glycoprotein-dependent MDR phenotype and elucidated their molecular mechanism of action. Cytotoxicity assays using human MDR1-transfected NIH-3T3 cells allowed us to select the most potent sesquiterpenes reversing the in vitro resistance to daunomycin and vinblastine. Flow cytometry experiments showed that the above active compounds specifically inhibited drug transport activity of P-glycoprotein in a saturable, concentration-dependent manner (K(i) down to 0.24 +/- 0.01 micromol/L) but not that of ABCC1 (multidrug resistance protein 1; MRP1), ABCC2 (MRP2), and ABCG2 (breast cancer resistance protein; BCRP) transporters. Moreover, sesquiterpenes inhibited at submicromolar concentrations the P-glycoprotein-mediated transport of [(3)H]colchicine and tetramethylrosamine in plasma membrane from CH(R)B30 cells and P-glycoprotein-enriched proteoliposomes, supporting that P-glycoprotein is their molecular target. Photoaffinity labeling in plasma membrane and fluorescence spectroscopy experiments with purified protein suggested that sesquiterpenes interact with transmembrane domains of P-glycoprotein. Finally, sesquiterpenes modulated P-glycoprotein ATPase-activity in a biphasic, concentration-dependent manner: they stimulated at very low concentrations but inhibited ATPase activity as noncompetitive inhibitors at higher concentrations. Sesquiterpenes from Celastraceae are promising P-glycoprotein modulators with potential applications in cancer chemotherapy because of their MDR reversal potency and specificity for P-glycoprotein.