三氧化二砷对人肝癌多药耐药细胞Bel-7402作用相关机制的研究

目的研究As2O3诱导多药耐药人肝癌细胞Bel-7402/VCR凋亡及相关基因表达的情况。方法MTT法观察细胞生长和对VCR敏感性,应用形态学手段和流式细胞术检测细胞凋亡,应用免疫组织化学研究多药耐药相关基因表达的影响。结果As2O3对Bel-7402/VCR及Bel-7402细胞的生长抑制均呈明显的量效关系;Bel-7402/VCR及Bel-7402凋亡细胞百分比随着As2O3作用时间延长和作用浓度的增加明显增加;As2O3对Bel-7402/VCR及Bel-7402MDR1阳性表达率为81.6%和80.2%。结论As2O3在体外表现出较强的逆转肝癌多药耐药性作用。     

三氧化二砷对人肝癌多药耐药细胞Bel-7402作用相关机制的研究

目的研究As2O3诱导多药耐药人肝癌细胞Bel-7402／VCR凋亡及相关基因表达的情况。方法MTT法观察细胞生长和对VCR敏感性,应用形态学手段和流式细胞术检测细胞凋亡,应用免疫组织化学研究多药耐药相关基因表达的影响。结果As2O3对Bel-7402／VCR及Bel-7402细胞的生长抑制均呈明显的量效关系;Bel-7402／VCR及Bel-7402凋亡细胞百分比随着As2O3作用时间延长和作用浓度的增加明显增加;As2O3对Bel-7402／VCR及Bel-7402MDR1阳性表达率为81．6％和80．2％。结论As2O3在体外表现出较强的逆转肝癌多药耐药性作用。     

Xpert MTB/RIF检测技术用于耐多药结核分枝杆菌利福平耐药检测分析

目的了解利福平耐药实时荧光定量核酸扩增检测技术(Xpert MTB/RIF)用于福建省耐多药结核病(MDRTB)利福平耐药检测的可行性。方法对来源于福建省结核病耐药性监测30个监测点纳入的79株耐多药和40株全敏感结核分枝杆菌分离菌株进行Xpert MTB/RIF检测,同时用PCR测序验证是否存在利福平耐药位点突变。结果119株菌Xpert MTB/RIF检测结果均为结核分枝杆菌。以比例法药物敏感试验结果作为对照,Xpert MTB/RIF检测MDR结核分枝杆菌利福平耐药的敏感度为97.47%(77/79),特异度为100.00%(40/40),Xpert MTB/RIF检测结果与PCR测序结果的一致性达到100%。结论 Xpert MTB/RIF方法用于耐多药结核分枝杆菌利福平耐药检测的意义较大,可用于福建省MDR-TB的快速筛查。     

姜黄素对HL60/ADR细胞多药耐药逆转作用的研究

目的:研究姜黄素对白血病耐药细胞HL60/ADR多药耐药的逆转作用.方法:用不同浓度姜黄素联合阿霉素处理HL60/ADR细胞,MTT法检测药物对细胞的生长抑制作用;流式细胞仪检测细胞内阿霉素的浓度及bcl-2表达水平.结果:HL60/ADR细胞经0.4,0.8μg/rml姜黄素作用24 h后,阿霉素的IC50分别为3.79、2.58 μg/ml,耐药逆转倍数为1.37、2.02,细胞内ADR浓度增加,bcl-2蛋白的表达下降.结论:姜黄素能部分逆转HL60/ADR细胞的多药耐药.     

EGCG对人肝癌HepG2细胞增殖和侵袭的影响

目的探讨表没食子儿茶素没食子酸酯(EGCG)对肝癌HepG2细胞增殖和侵袭的影响及可能的分子机制。方法不同浓度EGCG对HepG2细胞进行干预后,CCK-8法检测EGCG对肝癌HepG2细胞增殖的影响;荧光显微镜及流式细胞术(FCM)Annexin V-FITC/PI双染法检测EGCG对HepG2细胞的凋亡诱导作用;Transwell侵袭实验检测EGCG对HepG2细胞侵袭的影响;ELISA法检测HepG2细胞中基质金属蛋白酶-2(MMP-2)和血管内皮生长因子(VEGF)的表达水平。结果EGCG各浓度组干预HepG2细胞24、48h后,细胞的生长增殖均明显受到抑制,其24h IC25值和IC50值分别为58.19和133.90mg/L。以60、135mg/L EGCG干预肝癌HepG2细胞24h后,FCM结果显示药物组细胞凋亡率明显高于对照组(P<0.05),荧光显微镜观察显示随着药物浓度的增加,细胞凋亡程度加重。Transwell侵袭实验显示,60、135mg/L EGCG对HepG2细胞侵袭力抑制率分别为69.47%和100%(P<0.05)。ELISA检测结果显示,EGCG干预后HepG2细胞上清液中MMP-2和VEGF表达水平下降(P<0.05)。结论 EGCG对人肝癌HepG2细胞具有抑制增殖和侵袭作用,其机制可能与EGCG诱导HepG2细胞凋亡和抑制肿瘤细胞中MMP-2及VEGF表达水平有关。     

汉中地区耐亚胺培南铜绿假单胞菌耐药机制及脉冲场凝胶电泳分型

目的 探讨汉中地区耐亚胺培南铜绿假单胞菌的耐药机制,为有效控制多药耐药铜绿假单胞菌感染提供依据.方法 采用琼脂稀释和Etest法对汉中地区3201医院2006年1月-2008年3月临床分离的70株耐亚胺培南铜绿假单胞菌进行耐药性分析;双纸片协同法和Etest法检测金属酶;聚合酶链反应(PCR)检测β-内酰胺酶基因和oprD2基因;用实时定量PCR方法(qRT-PCR)检测oprD2、ampC基因的表达;脉冲场凝胶电泳(PFGE)分析菌株同源性.结果 70株耐亚胺培南铜绿假单胞菌对多黏菌素、氨曲南、头孢他啶的有较高的敏感性;仅1株产IMP-9型金属酶;65株菌未表达oprD2;4株菌过表达ampC基因;基因测序分析62株菌的oprD2基因均在同一位点正向插入序列ISpa1328;PFGE分型显示,耐亚胺培南铜绿假单胞菌在院内以单克隆流行为主.结论 70株耐亚胺培南铜绿假单胞菌在同一所医院多个科室的单克隆播散,是汉中地区近两年来铜绿假单胞菌对亚胺培南耐药的主要原因,插入序列ISpa1328引起的OprD2的缺失,是汉中地区铜绿假单胞菌对亚胺培南耐药的主要机制.     

子宫内膜样癌孕激素耐药细胞和组织中β-catenin的表达

目的拟明确β-catenin在子宫内膜样癌孕激素耐药中的作用。方法采用实时定量PCR方法检测Ishikawa细胞株和耐醋酸甲羟孕酮(Ishikawa-MPA)细胞株中β-catenin的表达差异;采用免疫组织化学和实时定量PCR方法检测孕激素治疗敏感与耐药组织中β-catenin的表达差异。结果 Ishikawa-MPA细胞株中β-catenin的表达高于Ishikawa(P=0.007),重度非典型增生和Ia1期子宫内膜样癌患者中,β-catenin的mRNA和蛋白水平的表达在孕激素治疗耐药组均高于敏感组(P=0.000,P=0.003)。结论孕激素耐药的发生与Wnt/β-catenin信号通路密切相关,孕激素治疗时Wnt/β-catenin信号通路抑制剂有助于耐药性的逆转。     

乌鲁木齐市耐多药结核分枝杆菌基因突变特征分析

目的 了解耐四种一线抗结核药物结核分枝杆菌的有关基因突变特征。方法 对19例耐多药结核病患者和254例全敏结核病患者痰液标本中分离的结核分枝杆菌进行药物敏感性试验,提取其DNA进行PCR扩增,对扩增产物测序并与标准株H37Rv进行比对。结果 19株耐多药结核杆菌和254株全敏结核杆菌均未检测到耐异烟肼基因inhA突变;耐多药组突变率最高的为耐异烟肼katG基因,突变位点为315;耐利福平的突变基因是rpoB,耐药位点为526和531,531位点突变率高于526位点;耐乙胺丁醇的突变基因是embB,耐药位点为206;耐链霉素的突变基因是rpsL和rrs,耐药位点分别为43和1401,rpsL基因的突变率高于rrs基因。结论 耐多药结核分枝杆菌耐异烟肼、利福平、乙胺丁醇、链霉素的突变基因分别为katG、rpoB、embB、rpsL和rrs,这对今后乌鲁木齐市耐多药结核病的快速诊断和控制提供了理论依据。     

志贺菌敏感株诱导耐药与marOR基因突变关系

目的对志贺菌敏感株进行诱导使其耐多药,研究其诱导耐药前后marOR基因的差异。方法用4类抗生素的次抑菌浓度对临床分离鉴定的志贺菌敏感株进行诱导耐多药试验。对志贺菌敏感株及诱导耐多药株的marOR基因进行聚合酶链反应(PCR)扩增后,测序比较其诱导耐药前后marOR基因序列的差异。结果成功获得志贺菌诱导耐多药株,命名为YD株;其最小抑菌浓度(MIC)分别为初始菌株的6～8倍;该诱导耐药株对庆大霉素、诺氟沙星、磺胺甲基异恶唑、头孢噻吩等均耐药;测序结果发现诱导耐药株marOR基因YD株有6个位点出现突变,其中5个为同义突变,1个为错义突变(1630位点A→G,赖氨酸→精氨酸)。结论 marOR基因的突变可能是志贺菌诱导耐药的调控机制之一。     

多药耐药鲍氏不动杆菌外排泵基因表达的研究

目的探讨鲍氏不动杆菌对常用抗菌药物的耐药性及与外排泵adeA基因表达水平之间的关系。方法琼脂两倍稀释法检测鲍氏不动杆菌对17种常用抗菌药物的最低抑菌浓度(MIC);PCR法扩增外排泵编码基因adeA;实时荧光定量RT-PCR法检测adeA基因的mRNA表达水平。结果药敏结果显示,耐药率最高的是亚胺培南,其次是头孢哌酮/舒巴坦,耐药率分别为92.9%、78.8%,临床常用的氨苄西林/舒巴坦、头孢吡肟、阿米卡星、氧氟沙星及环丙沙星耐药率均>50.0%;氨曲南、哌拉西林、头孢噻肟、头孢曲松等抗菌药耐药率相对较低;85株鲍氏不动杆菌中有多药耐药株52株,占61.2%;adeA基因的检出阳性率为81.2%,实时定量RT-PCR结果显示,多药耐药菌株adeA基因的mRNA相对表达量均高于敏感菌株,其中3株相对表达量为敏感菌株平均表达水平>20倍。结论临床分离的鲍氏不动杆菌株耐药情况严重,其主动外排系统adeA基因表达增强在多药耐药性形成中起重要作用。     

人参皂苷Rg3对人肺腺癌细胞株A549/DDP抑制转移及逆转耐药作用的研究

目的:探讨人参皂苷Rg3抑制人肺腺癌细胞株A549/DDP的浸润及转移和逆转其耐药作用及机制。方法:应用MTT法检测Rg3对A549/DDP细胞逆转耐药的作用;用细胞膜流动性实验检测Rg3对A549/DDP细胞膜流动性的改变用穿膜实验检测Rg3对A549/DDP细胞侵袭和转移的影响;用Western blotting实验检测Rg3对转移和耐药相关蛋白表达的影响。结果:Rg3作用后,A549/DDP细胞对顺铂的耐药性下降I,C50明显降低(P<0.05),细胞膜的流动性明显降低(P<0.05),细胞的穿膜能力明显降低(P<0.05),Rg3作用后,nm23及caspase-3的表达明显上调,LRP的表达无明显改变。结论:Rg3可通过上调nm23的表达抑制A549/DDP细胞的侵袭和转移能力,还可通过上调caspas-3的表达,降低细胞膜的流动性达到逆转耐药的作用。     

Modulation of the multidrug resistance (MDR) phenotype in CEM MDR cells simultaneously exposed to anti HIV-1 protease inhibitors (PI's) and cytotoxic drugs

Vinblastine, vincristine and doxorubicyn are currently used in chemotherapeutic treatments of several malignancies including HIV-1 associated tumours Kaposi's sarcoma (KS) and non-Hodgkin lymphoma (NHL). Hence, AIDS patients also affected by KS and NHL may be simultaneously subjected to highly active antiretroviral therapy (HAART) and cytotoxic drugs to combat HIV-1 infection and cancer aggressiveness. In order to assess if the combination of these therapies may affect cell growth and survival of P-glycoprotein expressing MDR variants of the human CD4+ T-lymphoblastoid CEM cell line, the protease inhibitors (PI's) ritonavir, saquinavir and indinavir were tested in an in vitro assay for their ability to potentiate the vinblastine, vincristine and doxorubicyn cytotoxicity. The results we obtained demonstrated that at the concentration of 10 micrograms/ml, ritonavir and in a lesser extent saquinavir act as MDR reversing agents. By contrast, the PI indinavir at least in the CEM cell system, does not affect the patterns of drug resistance. The level of chemosensitization exerted by ritonavir and saquinavir suggests that these PI's may render P-glycoprotein expressing MDR cells de novo susceptible to the antineoplastic drugs vinblastine, vincristine and doxorubicyn.     

Reversal of drug-resistant falciparum malaria by calcium antagonists: potential for host cell toxicity

Agents capable of reversing multidrug resistance (mdr) in falciparum malaria were investigated for potentiation of chloroquine accumulation and toxicity in a cell culture system. Verapamil, its analog RO11-2933, and desipramine caused a dose-dependent increase in the accumulation of chloroquine (CQ) within human and mouse hepatocytes but not human lung cells. Only those cells in which drug accumulation was enhanced by reversing agents reacted positively for P-glycoprotein (PgP)--the putative mediator of the enhanced drug efflux characteristic of mdr. Clinically achievable concentrations of verapamil (0.4 microM) and desipramine (1 microM) increased CQ accumulation within primary mouse hepatocytes by more than 50%. A well-differentiated normal human cell line (Hep-G2) was killed in media containing a combination of supraphysiological concentrations of CQ and verapamil but survived the same concentrations of either drug alone. Reversing agents may block PgP-mediated drug export from normal tissues as well as from MDR cells. Iatrogenic toxicity resulting from this accumulation of potentially toxic drugs such as CQ within normal cells could complicate the reversal of mdr in vivo.     

Genotoxic effects of green tea extract on human laryngeal carcinoma cells in vitro

Green tea (Camellia sinensis) contains several bioactive compounds which protect the cell and prevent tumour development. Phytochemicals in green tea extract (mostly flavonoids) scavenge free radicals, but also induce pro-oxidative reactions in the cell. In this study, we evaluated the potential cytotoxic and prooxidative effects of green tea extract and its two main flavonoid constituents epigallocatechin gallate (EGCG) and epicatechin gallate (ECG) on human laryngeal carcinoma cell line (HEp2) and its cross-resistant cell line CK2. The aim was to see if the extract and its two flavonoids could increase the sensitivity of the cisplatin-resistant cell line CK2 in comparison to the parental cell line. The results show that EGCG and green tea extract increased the DNA damage in the CK2 cell line during short exposure. The cytotoxicity of EGCG and ECG increased with the time of incubation. Green tea extract induced lipid peroxidation in the CK2 cell line. The pro-oxidant effect of green tea was determined at concentrations higher than those found in traditionally prepared green tea infusions.     

The Effect of Different Treatments of (–)-Epigallocatechin-3-Gallate on Colorectal Carcinoma Cell Lines

Backgroud: (-)-Epigallocatechin-3-gallate (EGCG), the major component of green tea, is well documented to induce apoptosis and cell cycle arrest in cancer by targeting multiple signal transduction pathways. However, EGCG is extremely unstable in general culture conditions and rapidly degraded. So, to what extent EGCG or which degradation products of EGCG play a role in anti-tumor is still unknown. In this study, we evaluated the effect of different treatments of EGCG on HCT116 cells.

Design: MTT assay was applied to evaluated the inhibitory effect of different treatments of EGCG on HCT116 cells. Cell cycle and apoptosis were performed by flow cytometry. Finally, western blot analysis was used to elucidate the molecular mechanism associated with cell cycle arrest and apoptosis.

Results: Compared with control, both EGCG and O-EGCG (i.e., EGCG being pre-incubated at 37°C for 3 h) significantly inhibited HCT116 cells growth. Surprisingly, we found that the inhibitory effect of O-EGCG was stronger than that of EGCG. The IC₅₀ values of EGCG and O-EGCG were 8.75 and 5.40 μM, respectively. Cell cycle analysis showed that 20 μM of EGCG simultaneously caused cell cycle arrest at G1 and G2 phase in HCT116 cells, differing from O-EGCG which exclusively caused cell cycle arrest at G2. This result suggested that parent EGCG at the early treatment might cause cell cycle arrest at G1. As time went on, EGCG disappeared and degraded products of EGCG were formed which might cause cell cycle arrest at G2. Further studies revealed that EGCG induced cell cycle arrest at G1 by downregulation of cyclin E and cyclin D1 and upregulation of p21. On the other hand, O-EGCG induced HCT116 cells apoptosis mainly by increasing the expression of p53 and cleaved caspase-3, which might be the underlying reason why O-EGCG had stronger inhibitory effect on HCT116 cells line than EGCG.

Conclusions: The pretreatment of EGCG may be an effective way to enhance its antitumor effect.     

多药耐药相关蛋白及谷胱甘肽-S-转移酶π与人肺癌多药耐药细胞系SPC-A1/TAX耐药性关系研究

目的研究多药耐药相关蛋白(MRP)、谷胱甘肽-S-转移酶π(GST-π)与人肺腺癌多药耐药细胞系SPC-A1/TAX多药耐药性之间的关系。方法采用S-P免疫组化法检测细胞MRP、GST-π的表达;采用MTS法分别检测并比较SPC-A1、SPC-A1/TAX细胞对6种不同化疗药物的敏感性。结果耐药组MRP、GST-π表达均为阳性,亲本组MRP、GST-π表达均为阴性,耐药组与亲本组间差异有统计学意义(P<0.05,P<0.01);SPC-A1/TAX较SPC-A1除对原诱导药物TAX具有耐受性外,对其他5种抗肿瘤药物也表现出不同程度的耐药性。结论MRP、GST-π在SPC-A1/TAX细胞系中表达与该人肺腺癌多药耐药细胞系的MDR具有相关性,是其MDR产生的可能机制。     

Evaluation of Hydro-Alcoholic Extract of Eclipta alba for its Multidrug Resistance Reversal Potential: An In Vitro Study

The development of multidrug resistance (MDR) causes problems in the chemotherapy of human cancer. The present study was designed to evaluate and establish the role of Eclipta alba as MDR reversal agent using multidrug resistant hepatocellular carcinoma cell line (DR-HepG2). To develop DR-HepG2, hepatocellular carcinoma cell line (HepG2) was transfected with 2-Acetylaminofluorene (AAF) and Aflatoxin B1 (AFB). Cytotoxic effects of the Eclipta alba hydroalcoholic extract (EAE) and standard anti-ancer drug Doxorubicin (DOX) were determined in DR-HepG2 and the parental cells HepG2 using MTT assay. The expression level of MDR1 gene and P-glycoprotein (P-gp) level was analyzed by RT-PCR and western blotting. From the present investigation, it was found that EAE (10 and 20 μg/ml) could significantly inhibit cell proliferation in DR-HepG2 whereas DOX (0.5 μg/ml) could not because of enhancement effect of MDR1/P-gp. This study demonstrated for the first time the antiproliferative activities of EAE in multidrug resistant DR-HepG2 cells. The findings revealed that Eclipta alba components are effective inhibitors of MDR1/P-gp.     

表没食子儿茶素没食子酸酯体外诱导HL-60细胞凋亡

目的 为研发天然抗白血病新药，研究茶多酚主要活性成分表没食子儿茶素没食子酸酯(EGCG)体外诱导细胞凋亡的作用。方法 采用体视显微镜、DNA凝胶电泳及透射电镜技术，观察EGCG对体外诱导人急性早幼粒白血病细胞(HL-60)凋亡的影响及其诱导凋亡的最佳作用时间和最佳作用浓度。结果 发现EGCG实验组中，HL—60细胞生长被显著抑制，DNA凝胶电泳中可见DNA条带，其细胞超微结构明显改变。当250ug／m1 EGCG作用细胞6h时，其诱导细胞凋亡的作用最明显。结论 EGCG可体外诱导HL-60细胞凋亡．可能是抗白血病的侯选药。     

儿茶素对LoVo细胞生长周期的影响和诱导凋亡的作用

目的 探讨表没食子儿茶素没食子酸酯（ＥＧＣＧ）、表没食子儿茶素（ＥＧＣ）、表儿茶素没食子酸酯（ＥＣＧ）和表儿茶素（ＥＣ）对大肠癌ＬｏＶｏ细胞生长周期的影响和它们诱导ＬｏＶｏ细胞凋亡作用及其差异性。方法 用ＭＴＴ法、琼脂糖凝胶电泳、透射电镜和流式细胞术观察４种儿茶素处理ＬｏＶｏ细胞后,它们对ＬｏＶｏ细胞的生长抑制作用、细胞生长周期的改变以及诱导其凋亡形态学和生化方面的改变。结果 ＥＧＣＧ和ＥＧＣ对Ｌ