下调Beclin1 抑制卵巢癌A2780/DDP细胞对顺铂的耐药性

目的：探究敲减Beclin1 表达对卵巢癌细胞A2780 对顺铂耐药的影响及其相关机制。方法：以Western blotting 及qPCR 检测卵巢癌细胞株A2780 及耐药细胞株A2780/DDP 中Beclin1 的表达情况；A2780/DDP 细胞转染Beclin1 siRNA 后，用MTT法检测细胞对顺铂敏感性的变化，克隆形成实验检测各组细胞的克隆形成情况，流式细胞术检测各组细胞的凋亡，MDC荧光染色检测细胞的自噬情况，Western blotting 检测自噬相关蛋白、溶酶体相关膜蛋白Lamp-2 以及组织蛋白酶Cathepsin B的表达情况。结果：顺铂耐药细胞株A2780/DDP 中Beclin1 mRNA及蛋白的表达水平均明显高于A2780 细胞株（均P<0.05），在A2780细胞中加入顺铂刺激后Beclin1 蛋白的表达水平显著升高（P<0.05）。敲减Beclin1 表达可促进顺铂诱导的A2780/DDP 细胞的凋亡（P<0.05）、抑制细胞自噬的发生（P<0.05）、减少细胞克隆形成（P<0.05）和增加细胞对顺铂的敏感性（P<0.05）；Western blotting结果显示，敲减Beclin1 可上调A2780/DDP 细胞中cleaved-caspase 3 和Cathepsin B的蛋白水平，下调Atg3、Atg7、LC3Ⅱ/Ⅰ、Lamp-2的表达水平（均P<0.05）。结论：敲减Beclin1 表达可提高A2780/DDP细胞对顺铂的敏感性，其机制可能与调节自噬相关蛋白表达抑制细胞保护性自噬和影响溶酶体功能，从而促进顺铂诱导耐药细胞凋亡有关。     

凋亡相关蛋白的表达及Caspase-3活性改变与人卵巢癌细胞顺铂耐药的关系

背景与目的:以顺铂为基础的化疗是卵巢癌治疗的重要组成部分,对顺铂的耐药是卵巢癌治疗失败的原因之一。本研究探讨人卵巢癌顺铂耐药细胞株中凋亡相关蛋白表达及caspase-3活性与人卵巢癌细胞顺铂耐药的关系。方法:采用Westernblot法分析人卵巢癌顺铂敏感细胞株COC1和顺铂耐药株COC1/DDP中凋亡相关蛋白bcl-2、bcl-xL、bax、bcl-xS的表达,caspase-3活性和其底物多聚ADP核糖聚合酶(PARP)的变化,并应用流式细胞仪检查不同浓度顺铂作用COC1和COC1/DDP细胞后的细胞凋亡率。结果:在COC1/DDP细胞中,bcl-2和bcl-xL的表达明显高于COC1细胞,bax的表达无明显改变,bcl-xS在COC1和COC1/DDP细胞中均无表达。用顺铂处理后,COC1/DDP细胞中caspase-3活性、PARP裂解片段和凋亡率较COC1细胞均明显降低(P<0.05),且呈浓度依赖性。结论:人卵巢癌细胞对顺铂产生耐药可能与肿瘤细胞内凋亡抑制蛋白过度表达、caspase-3活性下降有关,而与凋亡诱导蛋白的表达无关。     

紫杉醇诱导的卵巢癌耐药细胞株的生物学特性及其保存

目的 研究紫杉醇诱导的卵巢癌耐药细胞株的生物学特性,探索耐药细胞的长期保存条件,以建立稳定的体外实验模型。方法 选用卵巢癌化疗敏感细胞株SKOV3,分别采用大剂量冲击和小剂量浓度递增诱导建立耐药的卵巢癌细胞株SKOV3/TAX300、SKOV3/TAX30。四甲基偶氮唑盐（MTT）法检测耐药细胞对化疗药物紫杉醇的IC50;比较耐药细胞和敏感细胞的细胞平板克隆形成、生长曲线倍增时间的差异;荧光定量PCR检测敏感细胞和耐药细胞中耐药相关基因的表达;比较无药冻存和加药冻存的方式对耐药细胞的保存效果。结果 耐药细胞SKOV3/TAX300,耐药指数为4.60,耐药细胞SKOV3/TAX30,耐药指数为51.31;与敏感细胞相比,耐药细胞体积增大,形态不规则,倍增时间延长。多药耐药基因1（MDR1）在两种耐药细胞中高表达,肺耐药相关蛋白（LRP）、蛋白激酶Cα（PRKCA）基因仅在SKOV3/TAX300中的表达增高,BCL-2样1基因（BCL2L1）在SKOV3/TAX30中低表达。耐药细胞冻存在含有药物的条件下,有利于耐药性的保持。结论 大剂量冲击和小剂量浓度递增两种方法诱导的耐药细胞为研究紫杉醇耐药机制建立了良好的体外模型,两种耐药细胞SKOV3/TAX300和SKOV3/TAX30具有不同的生物学特性。     

人类卵巢癌顺铂耐药细胞株OV1228／cDDP的建立及其生物学特性

 目的　建立人类卵巢癌细胞顺铂耐药细胞株OV1228／cDDP,并对其生物学特性进行检测。方法　采用顺铂浓度梯度递增法,建立人类卵巢癌顺铂耐药细胞株。通过细胞形态学观察、生长曲线和群体倍增时间测定、药物敏感试验、mdr-1和PKC-α基因及蛋白表达水平的测定,来评价OV1228／cDDP的生物学特性。结果　成功建立了OV1228／cDDP耐药细胞株,耐药指数（RI）为5.97,对多柔比星和5-氟尿嘧啶具有一定的交叉耐药性。与OV1228相比,OV1228／cDDP细胞异型性增加、细胞倍增时间延长;mdr-1和PKC-α在基因和蛋白表达水平均明显增高。结论　OV1228／cDDP细胞对顺铂耐药性稳定,并呈现一定的多药耐药特性,为进一步研究耐药逆转途径提供了实验基础。     

Neu RNAi对卵巢癌细胞生长、凋亡及药物敏感性的作用

目的探讨nenRNAi对卵巢癌耐药细胞株SKOV3／DDP细胞生长、凋亡及药物敏感性的作用,寻找下调基因表达并逆转化疗耐药的方法,为卵巢癌的基因治疗探索新途径。方法应用含有u6启动子的pSilencer 1．0-U6表达载体构建neu基因的小干扰RNA（siRNA）表达载体（pSilencer—neu）,用脂质体方法将pSilencer—neu转染卵巢癌顺铂耐药细胞株SKOV3／DDP,另设未转染组及转染pSilencer—control组为对照。显微镜下观察转染前后细胞的变化;用RT—PCR及Western Blot检测neu基因mRNA及蛋白的表达;MTT法检测细胞生长情况;流式细胞仪检测细胞凋亡及周期的变化;加入顺铂后检测RNAi对SKOV3／DDP顺铂药物敏感性的影响。结果neuRNAi可明显下调卵巢癌耐药细胞株SKOV3／DDP中neu的基因表达;使其细胞生长受到抑制,生长速度减慢,生长曲线低平;细胞凋亡增加且细胞周期发生变化,G1／G0期细胞增多,S期细胞则减少;顺铂耐药实验显示,转染RNAi的SKOV3／DDP细胞IC50明显下调,细胞凋亡率显著增加。结论应用RNAi可以部分阻抑neu基因在卵巢癌顺铂耐药细胞株SKOV3／DDP中的表达,使SKOV3／DDP细胞生长减慢、凋亡增加,而且对顺铂的敏感性增强。     

重组凋亡素诱导人卵巢癌细胞顺铂耐药株凋亡

[目的]探讨凋亡素基因（VP3）在卵巢癌细胞株CoC1及CoC1细胞耐药亚株CoC1/DDP中的诱导凋亡情况。[方法]构建重组凋亡素真核表达载体pcDNA3.1-VP3。在体外将pcDNA3.1-VP3转染入卵巢癌细胞株CoC1及CoC1细胞耐药亚株CoC1/DDP中,RT-PCR检测凋亡素在细胞中的表达,用流式细胞仪检测细胞凋亡。[结果]RT-PCR证实VP3基因在CoC1及CoC1/DDP中存在并在转录水平表达。转染pcDNA3.1-VP3细胞凋亡率明显高于转染空质粒组（P〈0.01）,转染pcDNA3.1-VP3细胞凋亡率CoC1/DDP细胞明显高于CoC1细胞（P〈0.01）。[结论]凋亡素诱导人卵巢癌细胞CoC1和CoC1顺铂耐药亚株CoC1/DDP凋亡,且更易诱导CoC1顺铂耐药亚株CoC1/DDP细胞的凋亡。     

A2M介导Fas信号传导途径提高卵巢癌对铂类化疗的敏感性研究

目的 探讨A2M基因的表达与卵巢癌患者耐药及预后的关系及其对Fas信号传导通路的影响。方法 利用癌症基因图集（The Cancer  Genome Atlas,TCGA）数据库中铂类敏感和耐药的卵巢癌患者的基因表达谱,分析A2M基因在铂类敏感和耐药患者中的表达差异。利用已构建的带有绿色荧光标记的卵巢癌SKOV3敏感细胞（SKOV3-GFP）和顺铂耐药细胞（SKOV3-GFP/DDPⅡ）进行裸鼠皮下种植,成瘤后分次予以顺铂体内干预,以实时荧光定量PCR（real-time quantitative PCR,qRT-PCR）技术检测不同次数顺铂干预后的肿瘤组织中A2M mRNA与Fas信号传导通路上重要节点基因的表达水平。用双变量线性回归分析A2M mRNA与所检测基因的表达量的相关性。结果 相对于铂类敏感病例,A2M mRNA在铂类耐药患者中的表达下降（P<0.05）,A2M mRNA的表达与耐药相关（P=0.02）,与卵巢癌患者总生存期、化疗间隔生存期和无疾病进展生存期高度相关（P均<0.001）,其表达量越高,患者生存期越长。A2M mRNA以及细胞凋亡相关的Fas信号传导通路上重要节点基因Fas、FADD、caspase10、caspase9 和caspase3随顺铂注射次数的增加,在耐药的移植瘤组织中相对低表达（P<0.001）;而其下游与DNA修复相关的基因PARP1随顺铂注射次数的增加,在耐药的移植瘤组织中相对高表达（P<0.05）。A2M mRNA的表达与Fas信号传导通路上节点基因的表达存在线性相关（P<0.05）。结论 A2M可能是卵巢癌顺铂耐药的潜在信号分子,它可能维持肿瘤细胞对铂类药物的敏感性。其在耐药细胞中的低表达可能通过某种机制抑制下游的Fas信号传导通路,使其传导失调,最终引起PARP1的表达上调,促进DNA修复,抑制细胞凋亡,诱发卵巢癌细胞对顺铂的耐药。     

拓扑替康促人卵巢癌顺铂耐药细胞株凋亡机制的初步研究

目的探讨拓扑替康(TPT)对人卵巢癌顺铂耐药细胞株A2780/DDP和COC1/DDP的杀伤和诱导凋亡活性及其作用机制.方法用MTT比色法测定TPT对人卵巢癌顺铂耐药细胞株A2780/DDP和COC1/DDP的杀伤效应;透射电镜和DNA凝胶电泳研究TPT对靶细胞的凋亡诱导活性;Western blot检测凋亡相关蛋白bcl-2和bax的表达.结果TPT对A2780/DDP和COC1/DDP细胞均有较强的体外杀伤作用,其IC50值分别为102.91 ng/ml和111.75 ng/ml;TPT能诱导A2780/DDP和COC1/DDP细胞产生凋亡,DNA凝胶电泳呈现典型的凋亡梯度,透射电镜观察到细胞核染色质固缩、边集,胞质浓缩,出现空泡等典型的凋亡超微结构改变;TPT不影响bcl-2蛋白表达,却能上调bax蛋白表达,增大bax/bcl-2比值,且呈剂量依赖性.结论TPT对人卵巢癌顺铂耐药细胞株A2780/DDP和COC1/DDP均有明显的杀伤和促凋亡作用,其机制可能与bax基因表达上调而提高bax/bcl-2比值有关.     

脑胶质瘤细胞顺铂耐药分子标志物筛选

背景与目的：顺铂是神经肿瘤化疗常用药物之一,耐药是疗效不佳原因之一。遗传学改变可以影响肿瘤细胞对化疗的敏感性。本研究旨在利用芯片-基因组杂交技术筛选胶质瘤细胞中与顺铂耐药相关的分子标志物。方法：用芯片-基因组杂交技术对我们先前采用顺铂剂量梯度爬升诱导的对顺铂高度耐药的U251/CP2细胞（IC50为76.5μg/mL）和亲代细胞U251细胞（IC50为1.2μg/ml）筛选与顺铂耐药相关的分子标志物。RT-PCR和实时荧光定量PCR用来对结果进行验证。结果：补体因子H相关蛋白1基因（CFHR1）和补体因子H相关蛋白3基因（CFHR3）在U251细胞中至少各自缺失了一个拷贝,在U251/CP2细胞中完全缺失。IL-7基因在U251/CP2细胞中的拷贝数为U251细胞的2～3倍。结论：CFHR1、CFHR3和IL-7基因可能与胶质瘤对顺铂耐药有关。     

重组改构人TNF逆转卵巢癌耐药细胞株SKOV3/DDP的耐药性及其机制

目的: 探讨重组改构人肿瘤坏死因子（recombinant mutant human tumor necrosis factor, rmhTNF）体外逆转人卵巢癌多药耐药细胞株SKOV3/DDP的耐顺铂（cisplatin,又称DDP）效应及其可能存在的作用机制。方法: 体外培养人卵巢癌多药耐药细胞株SKOV3/DDP，以MTT法检测rmhTNF对此耐药株的细胞毒作用，确定其对此细胞株的无毒剂量;同法测定无毒剂量rmhTNF干预后SKOV3/DDP对顺铂耐药性的变化，通过流式细胞术检测rmhTNF干预不同时间段SKOV3/DDP细胞株中GSTπ蛋白的表达，RTPCR方法分析rmhTNF处理SKOV3/DDP细胞前后MDR1基因的表达水平。结果: （1）50～12234 U/ml rmhTNF对SKOV3/DDP细胞增殖无明显抑制作用（细胞存活率均﹥90%），因此选用100 U/ml 作为逆转剂量（无毒剂量）;（2）单用DDP 24、48、72 h 的IC50为(23.29±0.43)、(8.97±0.69)、(6.43±0.79)μg/ml，联合100 U/ml rmhTNF和DDP用药使SKOV3/DDP的IC50分别降至（19.50±0.50）、（4.34±0.43）、（2.44±0.02）μg/ml，逆转倍数分别为1.19、206、2.64倍;（3）100 U/ml rmhTNF干预0、24、48、72 h后SKOV3/DDP细胞内GSTπ蛋白的表达随作用时间延长降低，MDR1基因的表达随作用时间延长降低。结论: rmhTNF对SKOV3/DDP有逆转耐药作用，其机制可能与下调GSTπ蛋白及MDR1基因表达有关。     

Biological comparison of ovarian cancer resistant cell lines to cisplatin and Taxol by two different administrations

Drug resistance is one of the major obstacles to chemotherapy of ovarian cancer. Studies with cell lines can serve as an initial screen for agents that might modulate drug resistance. To establish more appropriate models of drug resistance and explore whether the differences exist in the different drug resistant sublines selected by different treatments, we induced SKOV3 cell line using cisplatin (CDDP) and Taxol over a period of 16 months by the pulse (SKOV3/CDDP-P and SKOV3/Taxol-P) and intermittent incremental (SKOV3/CDDP-80 and SKOV3/Taxol-25) method, respectively. The resistant phenotype of the four resistant sublines, SKOV3/CDDP-P, SKOV3/CDDP-80, SKOV3/Taxol-P and SKOV3/Taxol-25, was very stable and the resistance index was 4.12, 11.50, 261.98 and 622.76, respectively. In cell morphology, the cells from pulse treatment had remarkable changes compared with the cells from intermittent incremental treatment. SKOV3/CDDP-80 and SKOV3/Taxol-P grew more slowly than SKOV3/CDDP-P and SKOV3/Taxol-25. Multidrug resistance gene 1, multidrug resistance protein 1, lung resistance protein and glutathione S-transferase pi mRNA expression of SKOV3/CDDP-P and SKOV3/Taxol-25 had greater changes than that of SKOV3/CDDP-80 and SKOV3/Taxol-P. The results suggest there are great differences between the resistant cell lines resulting from pulse and intermittent incremental method. The resistant cells selected by the intermittent method were more resistant than the cells selected by the pulse method. The two resistant sublines selected by the pulse method may serve as appropriate models for the study of mechanisms of drug resistance in ovarian cancer.     

耐顺铂相关基因MDR1、MRP、LRP及GST-π在非小细胞肺癌中的表达及与生存相关的Meta分析

目的:采用循证医学系统分析方法了解肿瘤耐顺铂相关基因与非小细胞肺癌的相关性,为科学制定化疗方案提供理论依据.方法:检索中国学术期刊网(CNKI)全文数据库、维普科技期刊、美国国立图书馆PUBMED;检索时间段为1979 - 2011年;获得符合纳入标准的关于非小细胞肺癌耐药相关基因MDR1、MRP、LRP及GST -π的文献研究27篇;采用Stata11.0进行统计分析.结果:非小细胞肺癌组织与正常肺组织耐药基因表达合并效应显示,非小细胞肺癌组织耐顺铂相关基因表达水平明显高于正常肺组织.4种基因合并OR值并计算95％可信区间,各基因表达结果按照OR值大小顺序,OR值及95％可信区间依次为GST -π30.86(16.03,59.40)、LRP 13.96(9.27,21.01)、MRP 12.69(8.36,19.26)、MDR1 8.03 (4.45,14.48),其中LRP及MRP基因3年死亡人数明显高于3年生存人数,OR值及95％可信区间分别为LRP 4.75(2.11,10.67)、MRP 4.61(2.28,9.32).结论:耐顺铂相关基因MRP、LRP、GST -π及MDR1在非小细胞肺癌组织中呈高表达,尤以GST -π基因为著,其余依次是LRP、MRP、MDR1基因.各基因在非小细胞肺癌组织中表达的高低直接影响化疗效果和预后,是非小细胞肺癌化疗耐药中的重要基因.     

HL-60/VCR多药耐药细胞株耐药机制的研究

背景与目的：白血病细胞对化疗药物的耐药是白血病治疗失败的主要原因,多药耐药细胞株为白血病多药耐药机制和逆转多药耐药性的研究提供了良好的模型。为探讨药物诱导产生多药耐药机制,我们对HL-60/VCR细胞的耐药机制进行了研究。方法：应用流式细胞术和一组抗体,对药物敏感细胞株HL-60和多药耐药细胞株HL-60/VCR细胞的耐药相关蛋白P-gp、MRP、LRP、BCRP、GST-π,以及凋亡调节蛋白bcl-2、bax、bcl-x、bad的表达进行分析。结果：在HL-60/VCR细胞株中,耐药相关蛋白P-gp、MRP、BCRP、GST-π分别是其在HL-60细胞株中的18.62、1.19、1.50、1.32倍,而LRP无变化。凋亡抑制蛋白bcl-2、bcl-x分别是其在HL-60细胞株中的2.48、1.25倍,凋亡调节蛋白bad是HL-60细胞株中的1.08倍;而凋亡诱导蛋白bax反而降低,是HL-60细胞株中的0.88倍。结论：多种机制参与HL-60/VCR的多药耐药,涉及耐药蛋白P-gp、MRP、BCRP和GST-π的表达增强,而且凋亡调节蛋白bcl-2、bax、bcl-x、bad均可能参与其耐药机制的形成。     

Induction of MRP5 and SMRP mRNA by adriamycin exposure and its overexpression in human lung cancer cells resistant to adriamycin.

Acquired anticancer drug resistance in cancer cells is often a result of an increase in levels of the ATP binding cassette (ABC) transporters that export anticancer drugs from cancer cells, suggesting that anticancer drugs may induce genes that mediate drug resistance in cancer cells. In this study, the induction of anticancer drug transporter gene expression by Adriamycin was examined in human lung cancer cell lines. Increased expression of MDR1, MRP5 and SMRP mRNA was observed 48 hr after the initiation of Adriamycin exposure in human lung cancer PC-14 cells and cisplatin-resistant PC-14/CDDP cells, in a dose-dependent manner as measured by TaqMan real-time RT-PCR. The levels of MRP-1, MRP2 and LRP mRNA were not altered by Adriamycin exposure. The biologic functions of the MRP5 and SMRP genes have not been fully clarified. To elucidate the relationship between Adriamycin resistance and MRP5 and SMRP, mRNA levels of MRP5 and SMRP in Adriamycin-resistant cell lines were compared with the parental cells. Increased expression of MRP5 and SMRP mRNA was observed in all 3 cell lines (SBC-3/ADM, AdR MCF7 and K562/ADM) by Northern blot analysis and RNase protection assay. These results suggest that subacute exposure of lung cancer cells to Adriamycin induced MRP5 and SMRP and that long-term exposure with Adriamycin selected the MRP5- and SMRP-overexpressing lung cancer cells. MRP5 and SMRP is a candidate molecule for acquired Adriamycin resistance in addition to MDR1.     

透明质酸寡糖调节A549/DDP多药耐药作用的研究

目的:通过研究透明质酸寡糖对人肺腺癌细胞系A549/DDP的P糖蛋白和多药耐药相关蛋白(MRP)、肺耐药蛋白(LRP)表达的影响,探讨透明质酸在引起肿瘤细胞多药耐药中的作用.方法: 将CD44单抗或透明质酸寡糖与A549/DDP细胞共培养48小时,放免法检测培养基中细胞所分泌透明质酸的含量,流式细胞仪检测经上述处理的A549/DDP表面MDR1 、MRP、LRP的表达率,MTT法检测在不同浓度顺铂作用下,各组细胞的存活率.结果: 经透明质酸寡糖处理后A549/DDP,分泌透明质酸较未处理组明显减少(P<0.05);且细胞表面与多药耐药相关的MDR1 、MRP、LRP的表达率均降低(P<0.05).另外,处理后的细胞,在不同浓度顺铂作用时,细胞凋亡率明显增加.结论: 体外条件下,透明质酸寡糖能逆转A549/DDP的耐药.     

Multiple gene expression analysis reveals distinct differences between G2 and G3 stage breast cancers, and correlations of PKC eta with MDR1, MRP and LRP gene expression.

A possible link between protein kinase C (PKC) and P-glycoprotein (P-gp)-mediated-multidrug resistance (MDR) was assumed from studies on MDR cell lines selected in vitro. The functional relevance of PKC for the MDR phenotype remains unclear, and the involvement of a particular PKC isozyme in clinically occurring drug resistance is not known. Recently, we have demonstrated significant correlations between the expression levels of the PKC eta isozyme and the MDR1 or MRP (multidrug resistance-associated protein) genes in blasts from patients with acute myelogenous leukaemia (AML) and in ascites cell aspirates from ovarian cancer patients. To extend these findings to further types of human tumours we analysed specimens from 64 patients with primary breast cancer for their individual expression levels of several MDR-associated genes (MDR1, MRP, LRP (lung cancer resistance-related protein), topoisomerase (Topo) II alpha/IIbeta, cyclin A and the PKC isozyme genes (alpha, beta1, beta2, eta, theta, and mu) by a cDNA-PCR approach. We found significantly enhanced mean values for MRP, LRP and PKC eta gene expression, but significantly decreased Topo II alpha and cyclin A gene expression levels in G2 tumours compared with G3. Remarkably, significant positive correlations between the MDR1, MRP or LRP gene expression levels and PKC eta were determined: MDR1/PKC eta (rs = +0.6451, P < 0.0001) n = 62; MRP/PKC eta (rs = +0.5454, P < 0.0001) n = 63; LRP/PKC eta (rs = +0.5436, P < 0.0001) n = 62; MRP/LRP (rs = +0.7703, P < 0.0001) and n = 62, MDR1/MRP (rs = +0.5042, P < 0.0001) n = 62. Our findings point to the occurrence of a multifactorial MDR in the clinics and to PKC eta as a possible key regulatory factor for up-regulation of a series of MDR-associated genes in different types of tumours.     

Drug resistance features and S-phase fraction as possible determinants for drug response in a panel of human ovarian cancer xenografts

Multidrug resistance (MDR) and more specifically the expression of P-glycoprotein (Pgp) have been studied extensively in vitro. Unfortunately, it appears that the predictive value of MDR recognized in vitro is mostly an incorrect measure to determine the responsiveness of a particular tumour in the clinic. This misunderstood or overvalued role of MDR might explain the failure of strategies to reverse Pgp function by the use of modulators in solid tumours. To obtain more insight in in vivo drug resistance we investigated a panel of 15 human ovarian cancer xenografts consisting of the most common histological subtypes known in ovarian cancer patients. The response rate to cisplatin, cyclophosphamide and doxorubicin in the xenografts resembled the results of phase II trials with these agents in ovarian cancer patients. This resemblance justifies drug resistance studies in this experimental in vivo human tumour system. We determined the expression levels of MDR 1, MRP 1, LRP and topoisomerase IIalpha mRNA by the RNase protection assay and the presence of MRP1 and LRP proteins by immunohistochemistry. The S-phase fraction was investigated as a separate parameter by flow cytometry. In none of the 15 ovarian cancer xenografts was MDR 1 expression detectable. The expression levels of MRP 1 and LRP were low to moderate and resembled the presence of the MRP1 and LRP proteins. There was a weak, inverse relationship between the expression levels of LRP and sensitivity to cisplatin and cyclophosphamide (r = -0.44 and -0.45), but not to doxorubicin. The levels of topoisomerase IIalpha varied among the xenografts (0.73-2.66) and failed to correlate with doxorubicin resistance (r = 0.14). The S-phase fraction, however, showed a relation with the sensitivity to cisplatin (r = 0.66). Among the determinants studied in ovarian cancer in vivo, LRP mRNA and the S-phase fraction were the best predictive factors for drug response and most specifically for the activity of cisplatin.     

Overexpression of multidrug resistance genes MDR1 and cMOAT in human hepatocellular carcinoma and hepatoblastoma cell lines.

Overexpression of either of the multidrug resistance genes MDR1 and MRP is associated with resistance of tumors to multiple chemotherapeutic agents. Overexpression of MDR1 has been reported in some cell lines derived from human hepatocellular carcinomas (HCC) and hepatoblastomas (HB). The human gene for cMOAT (), a homologue of MRP, is thought to mediate hepatobiliary excretion of organic anions and to be associated with cisplatin resistance. In this study, expression levels of MDR1 and cMOAT were examined in 9 human HCC and HB cell lines and 10 other human cancer cell lines. Overexpression of the cMOAT gene was observed in all 9 HCC and HB cell lines and 3 of 10 other cancer cell lines. Co-overexpression of the cMOAT and MDR1 genes was observed in 7 of 9 HCC and HB cell lines, but in none of the 10 other cancer cell lines. Seven of the HCC and HB cell lines that had overexpression of the cMOAT gene were shown to be highly resistant to cisplatin compared to 2 HCC cell lines with low levels of cMOAT expression. These findings suggest that overexpression of cMOAT could contribute to cisplatin resistance in HCC and HB.     

Increased LRP mRNA expression is associated with the MDR phenotype in intrinsically resistant human cancer cell lines

Multidrug resistance (MDR) in human cancer cells is multifactorial. Previously, we reported on the association between expression of P-glycoprotein (Pgp), the multidrug resistance-associated protein (MRP), and the lung resistance protein (LRP) with the MDR phenotype in the NCI panel of 60 human cancer cell lines used for in vitro anticancer drug screening. Eight cell lines from this panel, manifesting widely divergent levels of in vitro drug resistance were chosen to investigate the role of MRP and LRP expression at the molecular level. LRP mRNA levels, as determined by ribonuclease protection assay, varied significantly among the 8 cell lines, and correlated closely with in vitro drug resistance to both MDR and non-MDR related drugs. LRP mRNA expression was determined to be a stronger correlate of drug sensitivity than protein expression. In contrast, MRP mRNA levels were not significantly correlated with drug sensitivity. The rates of newly transcribed LRP or MRP mRNA did not correlate with mRNA levels, indicating that mRNA stability or other features of processing may be important in regulation of LRP and MRP mRNA levels. Using Southern blot analysis, LRP gene amplification was shown not to be associated with LRP overexpression. These data suggest that LRP expression may be an important determinant of the MDR phenotype in cell lines intrinsically resistant to cancer chemotherapeutic agents. Int. J. Cancer 72:1021–1026, 1997. © 1997 Wiley-Liss, Inc.     

MRP、GST-π、TopoⅡα和LRP在胃癌组织中的表达及意义

背景与目的:多药耐药相关蛋白(multidrugresistance-associatedprotein,MRP)、肺耐药蛋白(lungresistanceprotein,LRP)、谷胱甘肽转移酶(glutathione-S-transferase-π,GST-π)和拓扑异构酶Ⅱα(topoisomeraseⅡα,TopoⅡα)均在多药耐药中发挥重要作用。联合检测它们在胃癌组织中的表达,目前国内外报道极少。本研究旨在探讨联合检测MRP、GST-π、TopoⅡα、LRP在胃癌组织中的表达及意义。方法:应用免疫组化SP法检测MRP、GST-π、TopoⅡα、LRP在90例胃癌标本中的表达,采用χ2检验和Fisher精确检验分析它们表达的意义。结果:(1)MRP、GST-π、TopoⅡα、LRP在胃癌组织中的阳性表达率分别为88.9%、91.1%、74.4%和87.7%,均高于在正常胃粘膜组织中的表达(P<0.05)。(2)MRP、GST-π、LRP在高、中分化腺癌中的表达均高于低分化腺癌,而TopoⅡα在高、中分化腺癌中的表达低于低分化腺癌(P<0.05);此四者的表达情况在不同浸润程度及有/无淋巴结转移的胃癌组织之间均无统计学差异(P>0.05)。(3)MRP、GST-π、TopoⅡα、LRP两两间均无相关性。结论:MRP、GST-π、TopoⅡα和LRP均在胃癌原发性多药耐药中起重要作用,它们在胃癌组织中的表达与肿瘤分化程度有关,而与肿瘤浸润程度及是否有淋巴结转移无关。