大黄素对人胆管癌多药耐药细胞QBC_（939）/ADM的耐药逆转作用

目的探讨大黄素（Emodin,EM）对人胆管癌多药耐药细胞QBC939/ADM的耐药逆转作用。方法细胞生长周期、凋亡率采用流式细胞术（FCM）,多药耐药P糖蛋白（P-gP）以免疫组织化学（SP）法检测。结果阿霉素（ADM）、紫杉醇分别与EM联合作用于人胆管癌多药耐药细胞QBC939/ADM的凋亡率比单独作用有显著提高。细胞周期分布显示：ADM、紫杉醇分别与EM联合作用于人胆管癌多药耐药细胞QBC939/ADM,使QBC939/ADM阻滞于G2/M期的细胞数明显增加。EM和紫杉醇联合作用后,人胆管癌多药耐药细胞QBC939/ADM中多药耐药P糖蛋白（P-gP）的表达由72.00%降低到46.00%（P〈0.01）。结论EM对QBC939/ADM细胞的多药耐药性有逆转作用。其作用机理可能与人胆管癌细胞P-gP的表达有关,通过与化疗药物竞争性结合P-gP的结合位点发挥疗效。     

Reversal effect of a macrocyclic bisbibenzyl plagiochin E on multidrug resistance in adriamycin-resistant K562/A02 cells

Plagiochin E is a new macrocyclic bisbibenzyl compound isolated from Marchantia polymorpha. In the previous studies, we reported that when combined with fluconazole, plagiochin E had synergetic effects against the resistant strain of Candida albicans. Herein, we examined the reversal effect of plagiochin E on multidrug resistance in adriamycin-induced resistant K562/A02 cells and the parental K562 cells. Its cytotoxicity and reversal effects on multidrug resistance were assessed by MTT (3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl-tetrazolium bromide) assay. Apoptosis percentage of cells was obtained from Annexin V/fluorescein isothiocyanate (FITC) and propridium iodide (PI) double-staining. The effects of plagiochin E on P-glycoprotein activity were evaluated by measuring rhodamine 123 (Rh123)-associated mean fluorescence intensity and P-glycoprotein expression on the basis of the flow cytometric technology, respectively. The results showed that plagiochin E ranging from 2 to 12 mug/ml had little cytotoxicity against K562/A02 cells. When combined with adriamycin, it significantly promoted the sensitivity of K562/A02 cells toward adriamycin through increasing intracellular accumulation of adriamycin in a dose-dependent manner. Further study demonstrated that the inhibitory effect of plagiochin E on P-glycoprotein activity was the major cause of increased stagnation of adriamycin inside K562/A02 cells, indicating that plagiochin E, as a new class of mutidrug resistance inhibitor, may effectively reverse the multidrug resistance in K562/A02 cells via inhibiting expression and drug-transport function of P-glycoprotein.     

冬凌草甲素逆转SGC7901/ADR细胞的多药耐药性及其机制

目的 观察冬凌草甲素(Ori)对胃癌细胞株SGC7901/ADR多药耐药性的逆转及其作用机制.方法 用MTT法检测Ori的非细胞毒浓度及对SGC7901/ADR细胞株阿霉素敏感性的影响;免疫荧光法检测Ori对SGC7901/ADR细胞p-糖蛋白(P-gp)活性及表达的影响;RT-PCR法检测Ori对细胞MDR1基因转录的影响.结果 用Ori无毒剂量处理细胞后,细胞对阿霉素的逆转倍数为4.53,MDR1基因的转录降低了0.78,P-gp的表达率降低了18.83％.结论 Ori能逆转SGC7901/ADR细胞的多药耐药性,其机制为降低MDR1基因的转录和下调P-gp的表达.     

洛美利嗪对人白血病细胞K562/ADM多药耐药的逆转作用

目的：研究洛美利嗪(lomerizine，Lom)对人白血病细胞K562／ADM多药耐药逆转作用及机制。方法：使用MTT法检测Lom对K562／ADM多药耐药细胞柔红霉素(DNR)细胞毒性的影响，使用荧光分光光度计和流式细胞术分析Lom对K562／ADM多药耐药细胞胞内P—糖蛋白(P—glycoprotein，P—gp)底物—罗丹明123(rhodamine 123，Rh123)的累积情况。结果：Lom能明显提高DNR对K562／ADM多药耐药细胞的细胞毒作用，并可使胞内Rh123的浓度增加。K562敏感细胞株则不受影响。结论：Lom能显地抑制：K562／ADM多药耐药细胞上P—gp的活性，提高P—gp底物的胞内浓度，并增强其他抗癌药的细胞毒作用。     

洛美利嗪逆转K562/ADM细胞多药耐药性

目的研究洛美利嗪(lomerizine,Lom)逆转K562/ADM细胞多药耐药性的作用及机制。方法MTT法检测细胞毒作用,流式细胞仪研究Lom对ADM和长春新碱(vincristine,VCR)的K562/ADM细胞凋亡诱导作用的影响及对罗丹明123(rhodamine 123,Rh123)外排和P-糖蛋白(P-glycoprotein,P-gp)表达的作用。结果Lom明显提高ADM对K562/ADM多药耐药细胞的细胞毒作用及ADM和VCR的凋亡诱导作用,3,10和30 μmol·L^-1 Lom使K562/ADM对ADM的IC₅₀值由79.03 μmol·L^-1分别降至28.14,8.16和3.16 μmol·L^-1。Lom增加胞内ADM的蓄积浓度并抑制Rh123外排;但作用72 h后对K562/ADM细胞P-gp表达无影响。结论Lom通过抑制P-gp的活性逆转K562/ADM细胞的多药耐药性。     

三苯氧胺对晚期大肠癌多药耐药逆转作用研究

目的 探讨三苯氧胺对多药耐药大肠癌患者外周血淋巴细胞膜P-糖蛋白含量的影响及对FOLFOX4方案化疗效果的影响.方法 选择淋巴细胞膜 P-gp表达阳性大肠癌患者62 例,随机分为三苯氧胺组 (33 例) 和单纯化疗组 (29 例).应用流式细胞免疫学方法对两组患者治疗前后淋巴细胞膜 P-gp含量进行定量研究,观察化疗效果.结果 三苯氧胺能显著降低外周血淋巴细胞膜P-gp 含量(P< 0.01),提高P -g p 转阴率(P< 0.01),显著提高化疗总有效率(P< 0.01)、中位生存期(P< 0.05)和1年生存率(P< 0.01).结论 三苯氧胺能有效逆转晚期大肠癌多药耐药,提高化疗效果.     

Reversal of P-glycoprotein-mediated multidrug resistance in human hepatoma cells by hedyotiscone A,a compound isolated from Hedyotis corymbosa

1. Multidrug resistance is a major problem in hepatocellular carcinoma. Hedyotiscone A, a compound isolated from Chinese herbal medicine Hedyotis corymbosa (HC, family Rubiaceae), was used as the chemical marker to distinguish between HC and an anticancer herb Hedyotis diffusa (HD) in our previous study.

2. The present study aimed to investigate whether HA exhibited antiproliferative activities in multidrug-resistant hepatocellular carcinoma cells R-HepG2 and the parental cells HepG2 using MTT assay and [³H]-thymidine incorporation assay.

3. Our results showed that HA could significantly inhibit cell proliferation in R-HepG2 and HepG2 (IC₅₀?=?43.7 and 56.3 µg/mL, respectively), but not in normal human liver cells WRL-68 (IC₅₀ > 100 µg/mL) cells, suggesting its selective cytotoxic effects. Besides, HA induced apoptosis in R-HepG2 cells, as confirmed by annexin-V & propidium iodide staining, and DNA fragmentation assay. The caspase cascade was activated as shown by a significant increase of cleaved caspases-3, -7 and -9 in HA-treated R-HepG2 cells. The activities and protein expression of P-glycoprotein as well as mRNA expression of MDR1 were also decreased in HA-treated R-HepG2 cells.

4. Our study demonstrated for the first time the antiproliferative activities of hedyotiscone A in multidrug-resistant R-HepG2 cells. The findings revealed the potential of this compound in treating multidrug-resistant tumor.

     

Reversal of multidrug resistance in murine fibrosarcoma cells by thioxanthene flupentixol

Summary The purpose of this study was to identify calcium channel and calmodulin antagonists effective in increasing the cytotoxic effects of several chemotherapeutic drugs against UV-2237 murine fibrosarcoma MDR cells. Among 8 compounds tested at nontoxic concentrations, flupentixol, a piperazine-substituted thioxanthene, was the most potent in enhancing the cytotoxicity of anticancer drugs commonly associated with the multidrug resistant (MDR) phenotype, such as Adriamycin, actinomycin D, vinblastine, and vincristine, but not 5-fluorouracil, a drug usually unaffected by MDR. The chemosensitizing effects of flupentixol were produced by increasing intracellular drug accumulation via a mechanism unrelated to the binding of the plasma membrane P-glycoprotein.     

木香烃内酯对K562/A02细胞阿霉素耐药的逆转作用研究

目的探索木香烃内酯对白血病耐药细胞系K562/A02阿霉素耐药的逆转作用。方法将木香烃内酯与K562/A02细胞共培养72 h后,采用MTT法检测木香烃内酯对细胞生长的抑制作用。不同浓度木香烃内酯处理K562/A02细胞24 h后,采用Annexin V和PI双染法检测木香烃内酯对细胞的凋亡。不同浓度木香烃内酯与阿霉素共培养72 h后采用MTT法检测木香烃内酯对K562/A02细胞的耐药逆转情况。采用流式细胞仪检测木香烃内酯处理24 h之后K562/A02细胞阿霉素蓄积以及细胞膜表面P-糖蛋白(P-gp)的表达。结果木香烃内酯对K562/A02细胞的生长具有明显抑制作用,呈显著的剂量相关性。与对照组比较,2.5~50μmol/L木香烃内酯组K562/A02细胞存活率显著降低(P0.05、0.01、0.001)。随着木香烃内酯浓度的增加,凋亡细胞的比例明显增加。与对照组比较,不同浓度木香烃内酯组细胞凋亡比例显著升高(P0.05、0.01、0.001)。加入5μmol/L木香烃内酯后,使K562/A02细胞对阿霉素的敏感性提高12倍。木香烃内酯处理后K562/A02细胞内部阿霉素的蓄积明显增加,呈浓度相关性。与对照组比较,5、10μmol/L木香烃内酯组K562/A02细胞内部阿霉素的蓄积增加显著升高(P0.05)。细胞表面的P-gp的表达并无显著影响。结论木香烃内酯能够抑制K562/A02细胞增殖,诱导K562/A02细胞凋亡,增强阿霉素的化疗敏感性,逆转阿霉素耐药。     

Reversal of multidrug resistance by co-delivery of tariquidar (XR9576) and paclitaxel using long-circulating liposomes

One of the major obstacles to the success of cancer chemotherapy is the multidrug resistance (MDR) often resulting due to the overexpression of drug efflux transporter pumps such as P-glycoprotein (P-gp). Highly efficacious third generation P-gp inhibitors, like tariquidar, have shown promising results in overcoming the MDR. However, P-gp is also expressed in normal tissues like blood brain barrier, gastrointestinal track, liver, spleen and kidney. To maximize the efficacy of P-gp inhibitor and reduce the systemic toxicity, it is important to limit the exposure of P-gp inhibitors and the anticancer drugs to normal tissues and increase their co-localization with tumor cells. In this study, we have investigated the co-delivery of the P-gp inhibitor, tariquidar, and cytotoxic drug, paclitaxel, into tumor cells to reverse the MDR using long-circulating liposomes. Tariquidar- and paclitaxel-loaded long-circulating liposomes showed significant resensitization of the resistant variant for paclitaxel, which could be correlated with an increased accumulation of paclitaxel in tumor cells. These results suggest that the co-delivery of the P-gp inhibitor, tariquidar, and the cytotoxicity inducer, paclitaxel, looks like a promising approach to overcome the MDR.     

维拉帕米逆转肿瘤多药耐药性的研究进展

肿瘤细胞对化疗药物产生的多药耐药（MDR）已成为当前影响肿瘤化学治疗疗效的主要障碍，寻找低毒有效的MDR逆转剂是提高化疗疗效的关键。MDR产生机制复杂，由mdrl基因编码的P-糖蛋白（P-glycoprotein P-gp）的过表达是产生MDR的主要原因。维拉帕米是应用最早的MDR逆转剂之一，但其毒副作用大大限制了临床应用。从维拉帕米分离出的光学异构体R-型维拉帕米，在逆转肿瘤MDR时，更加高效安全，具有良好的临床应用前景。     

新的四氢异喹啉类化合物CPUE1逆转K562/A02细胞的多药耐药性

目的 :研究新的四氢异喹啉类化合物CPUE1逆转K5 6 2 A0 2细胞多药耐药性的作用及机制。方法 :在CPUE1的作用下 ,用MTT法检测长春新碱(vincristine ,VCR)对K5 6 2 A0 2多药耐药细胞的细胞毒作用的变化 ,使用DNA分析和Annexin Ⅴ PI双染法研究CPUE1对VCR诱导K5 6 2 A0 2细胞凋亡的影响 ,流式细胞仪检测CPUE1对P 糖蛋白 (P glycop rotein ,P gp)外排罗丹明 12 3(rhodamine12 3,Rh12 3)的作用。结果 :CPUE1能明显提高VCR对K5 6 2 A0 2多药耐药细胞的细胞毒作用以及凋亡诱导作用 ,10 μmol·L-1的CPUE1能使K5 6 2 A0 2对VCR的IC50值由 6 0 .5 4μmol·L-1降至 4 .17μmol·L-1。CPUE1还能抑制Rh12 3外排从而增加细胞内Rh12 3的蓄积浓度。结论 :CPUE1通过抑制P gp的活性逆转K5 6 2 A0 2细胞的多药耐药性。     

蛇床子素对耐阿霉素人乳腺癌细胞耐药的逆转作用

目的:研究蛇床子素(Ost)对人乳腺癌细胞阿霉素耐药株多药耐药(MDR)的逆转作用及其机制。方法:采用MTT比色法测定药物的细胞毒性,高效液相-紫外检测法检测细胞内ADR浓度。结果:Ost对MCF-7及MCF-7/ADR细胞均有增殖抑制作用,IC50值分别为(58.1±2.3)μmol.L-1和(59±5)μmol.L-1;在5~15μmol.L-1范围内,Ost可以不同程度地增强ADR对MCF-7细胞杀伤作用,与ADR联合用药降低ADR对MCF-7/ADR的IC50值,显著增加MCF-7/ADR细胞内ADR的积累。结论:Ost对人乳腺癌细胞株MCF-7及其阿霉素耐药株MCF-7/ADR细胞均有增殖抑制作用,而且Ost通过明显增加MCF-7/ADR细胞内ADR的浓度,逆转其阿霉素耐药性。     

补骨脂素逆转多药耐药细胞系K562/ADR耐药性研究

目的　研究补骨脂素对白血病细胞阿霉素耐药株(K5 6 2 /ADR)多药耐药 (multidrugresistance,MDR)性的逆转作用及其机制。方法　采用MTT法检测药物细胞毒性作用 ,高效液相色谱法检测细胞内阿霉素 (ADR)的浓度 ,流式细胞术测定细胞P 糖蛋白 (P gp)的表达。 结果　补骨脂素 (1～ 2 0 μmol·L-1)能不同程度地降低ADR对K5 6 2 /ADR细胞的IC50 。 2 0 μmol·L-1能显著提高ADR在K5 6 2 /ADR细胞内的浓度 ,降低K5 6 2 /ADR细胞P gp的表达。 结论　补骨脂素能逆转K5 6 2 /ADR细胞的MDR ,其机制与抑制P gp的功能及其表达 ,增加细胞内ADR的积累有关     

Effects of chemopreventive citrus phytochemicals on human P-glycoprotein and multidrug resistance protein 1

The effects of dietary chemopreventive citrus phytochemicals on the drug efflux transporters P-glycoprotein (ABCB1) and multidrug resistance protein 1 (MRP1, ABCC1) were investigated using P-glycoprotein-overexpressing human carcinoma KB-C2 cells and human MRP1 gene-transfected KB/MRP cells. The effects of natural chemopreventive citrus phytochemicals, such as auraptene, nobiletin, citral, citronellal, limonene, limonin, and synephrine were examined. The accumulation of daunorubicin, a fluorescent substrate of P-glycoprotein, increased in the presence of auraptene and nobiletin in KB-C2 cells. Nobiletin also increased the accumulation of calcein, a fluorescent substrate of MRP1, in KB/MRP cells. The ATPase activity of P-glycoprotein was stimulated by auraptene and nobiletin. The ATPase activity of MRP1 was stimulated by nobiletin. These results suggest that chemopreventive citrus phytochemicals, such as nobiletin found in oranges, have inhibitory effects on P-glycoprotein and/or MRP1, and may cause food–drug interactions.     

野木瓜果实总皂苷对BEL-7402/5 FU细胞多药耐药性的逆转作用

目的 研究野木瓜果实总皂苷对人肝癌耐药细胞BEL-7402/5 FU多药耐药(MDR)的逆转作用,并初步探讨其耐药逆转机制.方法 采用MTT法测定5-氟尿嘧啶(5-FU)、阿霉素(ADM)、丝裂霉素(MMC)和野木瓜果实总皂苷对BEL-7402细胞、BEL-7402/5 FU细胞的毒性及野木瓜果实总皂苷逆转MDR的效果;利用蛋白质印迹法检测P-糖蛋白(P-gp)的表达情况.结果 BEL-7402/5 FU细胞对5-FU、ADM、MMC的耐药指数分别为21.71,2.73,2.11;野木瓜果实总皂苷能有效抑制BEL-7402/5 FU细胞增殖,无细胞毒性剂量为5,10 μg/mL,逆转耐药倍数分别为1.36、1.93;野木瓜果实总皂苷联合5-FU作用BEL-7402/5 FU细胞,可降低P-gp蛋白表达.结论 野木瓜果实总皂苷能部分逆转BEL-7402/5 FU细胞MDR,其机制可能是通过下调P-gp的表达而实现的.     

Marine sponge-derived sipholane triterpenoids reverse P-glycoprotein (ABCB1)-mediated multidrug resistance in cancer cells

Previously, we reported sipholenol A, a sipholane triterpenoid from the Red Sea sponge Callyspongia siphonella, as a potent reversal of multidrug resistance (MDR) in cancer cells that overexpressed P-glycoprotein (P-gp). Through extensive screening of several related sipholane triterpenoids that have been isolated from the same sponge, we identified sipholenone E, sipholenol L and siphonellinol D as potent reversals of MDR in cancer cells. These compounds enhanced the cytotoxicity of several P-gp substrate anticancer drugs, including colchicine, vinblastine and paclitaxel, and significantly reversed the MDR-phenotype in P-gp-overexpressing MDR cancer cells KB-C2 in a dose-dependent manner. Moreover, these three sipholanes had no effect on the response to cytotoxic agents in cells lacking P-gp expression or expressing MRP1 (ABCC1) or MRP7 (ABCC10) or breast cancer resistance protein (BCRP/ABCG2). All three sipholanes (IC₅₀ >50 μM) were not toxic to all the cell lines that were used. [³H]-Paclitaxel accumulation and efflux studies demonstrated that all three triterpenoids time-dependently increased the intracellular accumulation of [³H]-paclitaxel by directly inhibiting P-gp-mediated drug efflux. Sipholanes also inhibited calcein-AM transport from P-gp-overexpressing cells. The Western blot analysis revealed that these three triterpenoids did not alter the expression of P-gp. However, they stimulated P-gp ATPase activity in a concentration-dependent manner and inhibited the photolabeling of this transporter with its transport substrate [¹²⁵I]-iodoarylazidoprazosin. In silico molecular docking aided the virtual identification of ligand binding sites of these compounds. In conclusion, sipholane triterpenoids efficiently inhibit the function of P-gp through direct interactions and may represent potential reversal agents for the treatment of MDR.     

L1210 cells cultivated under the selection pressure of doxorubicin or vincristine express common mechanisms of multidrug resistance based on the overexpression of P-glycoprotein

Multidrug resistance of neoplastic tissue is often associated with the overexpression and increased drug transport activity of plasma membrane transporters like P-glycoprotein (P-gp), multidrug resistance associated proteins (MRPs) or breast cancer resistance protein, as well as with the elevation of the glutathione detoxification pathway. We have already described the overexpression of P-gp under the selection pressure of vincristine in L1210 mouse leukemia cells. In the present study, mechanisms of multidrug resistance induced in L1210 cells cultivated in the presence of doxorubicin were analyzed. The selection pressure of both vincristine (yielding a resistant subline of L1210 cells, R_V) and doxorubicin (yielding a resistant subline of L1210 cells, R_D) induced a dramatic depression of cell sensitivity to both drugs. Both R_V and R_D cells demonstrated a lack of ability to accumulate calcein/AM and fluo-3/AM as fluorescent substrates of P-gp and MRP. The retention of dyes could be reached in both cell sublines by the application of inhibitors of P-gp (like verapamil) but not by probenecid – an inhibitor of anion transporters, including MRPs. Massive protein bands, at a M_r range of 130–180 kDa that interact with c219 antibody against P-gp, were detected in the crude membrane fraction isolated from both R_V and R_D (but not from L1210) cells by Western blot. The cytosolic activity of glutathione S-transferase was found to be similar in R_V and R_D cells and did not differ significantly from the activity ascertained in parental L1210 cells. Neither the R_V nor R_D cell sublines differed considerably, as measured by cell ultrastructure. In conclusion, based on P-gp overexpression, both doxorubicin and vincristine induce a common multidrug resistance phenotype in L1210 cells.     

N-糖基取代的邻苯二甲酰亚胺新衍生物的合成与肿瘤多药耐药逆转作用研究

沙利度胺（α-N-phthalimido-glutarimide，TLD）是一种具有抗血管生成和抗炎作用的药物，对多种实体瘤有效。本文研究了N-糖基取代的沙利度胺新衍生物（STA-35）对阿霉素（doxorubicin，ADR）引起的多药耐药（multidurg resistance，MDR）的调节作用。采用SRB法检测化合物对癌细胞的增殖抑制作用，应用流式细胞术测定P-糖蛋白（P-glycoprotein，P—gp）的功能，以免疫印迹方法考察P—gP的蛋白表达。实验结果表明，STA-35能够抑制人乳腺癌细胞MCF-7及其ADR耐药细胞MCF-7／ADR生长，耐药指数仅为1．19；并能增强MCF-7／ADR细胞对ADR的敏感性。此外，STA-35可以增加MCF-7／ADR细胞内罗丹明123（rhodamine 123，RH123）的聚积，减弱P—gP的功能，抑制P-gp的蛋白表达。该化合物具有多药耐药逆转作用，其分子机制可能与抑制P—gp的功能和蛋白表达相关。