Reversing multidrug resistance by RNA interference through the suppression of MDR1 gene in human hepatoma cells

AIM： To reverse the multidrug resistance （MDR） by RNA interference （RNAi）-mediated MDRI suppression in heparoma cells.METHODS： For reversing MDR by RNAi technology, two different short hairpin RNAs （shRNAs） were designed and constructed into pGenSil-1 plasmid, respectively. They were then transfected into a highly adriarnycin-resistant HepG2 hepatorna cell line （HepG2/ADM）. The RNAi effect on MDR was evaluated by real-time PCR, cell cytotoxicity assay and rhodarnine 123 （Rh123） efflux assy. RESULTS： The stably-transfected clones showed various degrees of reversal of MDR phenotype. Surprisingly, the MDR phenotype was completely reversed in two transfected clones. CONCLUSION： MDR can be reversed by the shRNAmediated MDRI suppression in HepG2/ADM cells, which provides a valuable clue to make multidrug-resistant hepatoma cells sensitive to anti-cancer drugs.

Congenital expression of mdr-1 gene in tissues of carcinoma and its relation with patho morphology and prognosis

AIM To detect the congenital expression patterns of mdr 1 gene in commonly encountered malignant tumors in clinic, and the relationship between the expression of mdr 1 gene and the prognostic morphology in esophageal carcinomas. METHODS A total of 151 resected samples of malignant tumors without preoperative treatment were taken from Anyang City Tumor Hospital. The congenital expression of their mdr 1 gene was detected with reverse transcription polymerase chain reaction (RT PCR) and was compared with each other. The positive incidence of mdr 1 gene in 46 samples of esophageal carcinoma was compared with their differentiated grades, TNM stages and macroscopic types, and the precautions and advantages of RT PCR were evaluated. RESULTS All the 151 samples were confirmed to be malignant histopathologically, including cancers of stomach and gastric cardia (n =51), esophagus ( n =46), colorectum ( n =16), breast ( n =15), thyroid ( n =10), lung ( n =9), uterine cervix ( n =24). The positive expression rate of their mdr 1 gene was 33 3%, 37%, 31 3%, 13 2%, 40%, 55%, and 0% respectively. All the 46 samples of esophageal carcinoma were pathologically confirmed to be squamous cell carcinoma. The total expression rate of their mdr 1 gene was 37% (17/46), 35% (6/17), 40% (8/20), and 33% (3/9) for differentiation grade Ⅰ, Ⅱ and Ⅲ respectively. The expression rate of TNM classification was 33% (6/18), 40% (5/12) and 37% (6/16) in stage Ⅱa, Ⅱb and Ⅲ. The expression rate was 33% (3/9) in ulcerous type, 37% (3/8) in constrictive one, 33% (5/15) in fungoid one, and 40% (6/14) in medullary one. No statistically significant difference was found. CONCLUSION Compared with other methods, RT PCR is more simple, reliable and accurate in detecting mdr 1 gene expression in tissues of tumor. The overexpression of mdr 1 gene in these neoplasms suggested that cases should be handled differently for chemotherapy with rational use of drugs. Excision is the chief treatment for carcinoma of esophagus. The expression of mdr 1 gene in tissues of esophageal cancer is correlated with the parameters of tumor molecular biology which are independent of histopathological morphology.

Association of single nucleotide polymorphisms of brain-derived neurotrophic factor gene and multidrug resistance 1 gene to refractory epilepsy in Chinese Han children

BACKGROUND： There are two hypotheses for the underlying cause of refractory epilepsy： ＂target＂ and ＂transport＂. Studies have shown that brain-derived neurotrophic factor （BDNF） is over-expressed in refractory epilepsy. Multidrug resistance 1 （MDR1） gene encodes for P-glycoprotein, the primary ATP-binding cassette transporter in the human body. Some single nucleotide polymorphisms of the MDR1 gene have been associated with refractory epilepsy. OBJECTIVE： To investigate the association between BDNF gene C270T polymorphism and MDR1 T-129C polymorphism with refractory epilepsy in Chinese Han children through the use of polymerase chain reaction （PCR）-restriction fragment length polymorphism analysis. DESIGN, TIME AND SETTING： A case-control, genetic association study was performed at the Central Laboratory, Third Xiangya Hospital of Central South University from June 2005 to November 2007. PARTICIPANTS： A total of 84 cases of unrelated children with epilepsy, including 41 cases of refractory epilepsy and 43 cases of drug-responsive epilepsy, were enrolled. An additional 30 healthy, Chinese Han children, whose ages and gender matched the refractory epilepsy patients, were selected as normal controls. METHODS： Venous blood was collected and genomic DNA was extracted from the blood specimens. C270T polymorphism in BDNF gene and T-129C polymorphism in MDR1 gene were genotyped using PCR-restriction fragment length polymorphism analysis. Association analysis using the Ftest and Chi-square test was statistically performed between C270T polymorphism in BDNF gene and T-129C polymorphism in MDR1 gene and refractory epilepsy. MAIN OUTCOME MEASURES： The distribution of genotypes and allele frequencies of C270T polymorphism in BDNF gene and T-129C polymorphism in MDR1 gene. RESULTS： The distribution of CC, CT, and TT genotypes, as well as C and T allele frequencies, in the BDNF gene was not significantly different between the refractory epilepsy group, drug-responsive epilepsy group, or the normal control group （P 〉 0.05）. The distribution of TT genotype and T allele frequencies of the MDR1 gene was significantly different in the refractory epilepsy group compared with the drug-responsive epilepsy and normal control groups （P 〈 0.05）. Comparison of haplotype combinations demonstrated that there were no significant differences in combinations of TT＋CC, -FI-＋CT, TC＋CC, and TC＋CT among the three groups （P 〉 0.05）. CONCLUSION： C270T polymorphism of the BDNF gene was not associated with refractory epilepsy in Chinese Han children, but T-129C polymorphism in the MDR1 gene was associated with refractory epilepsy in Chinese Han children. The TT genotype and T allele frequencies could serve as susceptibility loci for refractory epilepsy. Interactions between C270T in BDNF gene and T-129C in MDR1 gene were not observed in refractory epilepsy in Chinese Han children.

EXPRESSION OF mdr-1 GENE IN CANCER TISSUE AND ITS ASSOCIATION WITH MORPHOLOGICAL INDEXES OF ESOPHAGEAL CARCINOMA IN ANYANG

Objective: Overexpression of mdr-1 gene is associated with multidrug resistance (MDR) and aggressive characteristics of malignance. Our purposewas to detect the levels of P-gp expression in fresh untreated esophageal carcinomas, and to correlate these levels to current prognostic indicators of morphology.Methods: Reverse transcription polymerase chain reaction (RT-PCR) was used to investigate mdr-1 gene expression of 46 samples from untreated esophageal carcinoma, and compared the positive incidences among differentiated grades, TNM stages and macroscopic types.Results: All 46 samples were pathologically squamous cell carcinoma. The positive' incidences of mdr-1 gene expression were 37% (17/46) in whole group,35% (6/17), 40% (8/20), 33% (3/9), for Ⅰ,Ⅱ and Ⅲdifferentiated grades, respectively. The expression rates of 33% (6/18), 40% (5/12), and 37% (6/16), were found in Ⅱa, Ⅱ, and Ⅲ stage of TNM, respectively. In macroscopic type view, the positive incidence was 37%(3/8) in constrictive, 33% (5/15) in fungating, 40% (6/14)in marrowlike, 33% (319) in ulcerative type. There were no statistically significant differences among each category system of morphology.Conclusion: The result, high level expression of mdr-1 gene in untreated esophageal carcinoma, suggested the poor efficacy of chemotherapy for some esophageal carcinoma patients. And we should cautiously choose cases who will receive chemotherapy. Surgery is still the best treatment for carcinoma of esophagus. Besides, the data also revealed that the expression of mdr-1 gene in untreated esophageal cancer was independent of morphologic prognostic indexes, and that there were no correlation between mdr-1 gene expression and morphological indexes.

Expression of multidrug resistance 1 gene and C3435T genetic polymorphism in peripheral blood of patients with intractable epilepsy

BACKGROUND： Increased expression of multidrug resistance 1 （MDR1） mRNA in peripheral blood of patients with intractable epilepsy is not due to epilepsy drugs, but epilepsy behavior. Monitoring MDR1 expression in peripheral blood is a target for MDR1 gene evaluation. OBJECTIVE： To investigate the influence of antiepileptic drugs and seizures on MDR expression in intractable epilepsy, and to analyze the genetic polymorphisms of C3435T in the MDRl gene. DESIGN, TIME AND SETTING： Factorial designs and comparative observations at the experimental center of the Affiliated Hospital of Qingdao Medical College, Qingdao University between October 2003 and October 2004. PARTICIPANTS： A total of 120 subjects were recruited from the epilepsy clinical department of the Affiliated Hospital of Qingdao Medical College. Four groups （n = 30） were classified according to statistical factorial design： intractable epilepsy, treatment response, no treatment, and normal control groups. METHODS： One-step semi-quantitative reverse-transcription polymerase chain reaction technology was used to test expressions of the MDR1 gene in 120 subjects. C3435T polymorphisms in intractable epilepsy group and normal control groups were analyzed by polymerase chain reaction-restriction fragment length polymorphism. MAIN OUTCOME MEASURES： Expression of MDR1 mRNA in the four groups, and C3435T genetic polymorphisms in intractable epilepsy and normal control groups. RESULTS： MDRl gene expression was increased in the intractable epilepsy group, due to the factor seizures, but not the antiepileptic drugs. However, the interaction between the two factors was not statistically significant. Of the 30 subjects in the intractable epilepsy group, the following genotypes were exhibited： 3 （10%） C/C genotype, 9 （30%） C/T genotype, and 18 （60%） T/T genotype at the site of C3435T, while 4 （13%）, 10 （33%）, and 16 （53%） subjects were determined to express these genotypes in the normal control group, respectively. C and T allele frequency were 25% and 75% in the intractable epilepsy group, and 30% and 70% in the normal control group, respectively. However, there was no statistical difference between the groups. CONCLUSION： Results demonstrated that seizures, not antiepileptic drugs, induced MDR1 gene expression in intractable epilepsy. Genetic polymorphisms of C3435T in the MDR1 gene did not contribute to the development of multidrug resistance in patients with intractable epilepsy.

PRELIMINARY STUDY OF RETROVIRAL MEDIATED TRANSFER OF THE HUMAN mdr-1 GENE INTO MURINE AND HUMAN HEMATOPOIETIC STEM/PROGENITOR CELLS

To investigate the characteristics of multidrugresistance and transplantation of modified stem/ progenitor cells by multidrugresistant gene (mdr1 gene), we established PA317/MDR1 cell line which producing retroviruses by transfecting the retroviral vector PHaMDR1/A into packging cell line PA317 by Lipofectin. The virus titer of the supernatants was 1.2×105 cfu/ml. We transfected the murine hematopietic cells collected from 5FU pretreated mice and they showed the ability to reconstitute the longterm hematopoiesis of preirradiated mice. After 4 months, both of bone marrow cells and peripheral blood cells of transplanted mice still contained mdr1 gene. We also transfered mdr1 gene into human bone marrow CD34+ cells selected by using magnetic cell sorting system. PCR analysis showed that transduced CD34+ cells maintained the mdr1 cDNA. A fraction of CFUGM originated from transfected CD34+ cells had the charactor of resistance to Taxol. It is indicated that mdr1 gene can be transduced into murine and human stem/proginitor cells through retroviral mediated gene transfer and it protects the transfected cells from cytotoxic drugs.

Chitosan/pshRNA Plasmid Nanoparticles Targeting MDR1 Gene Reverse Paclitaxel Resistance in Ovarian Cancer Cells

In order to investigate the effect of chitosan/pshRNA plasmid nanoparticles targeting MDR1 genes on the resistance of A2780/TS cells to paclitaxel, chitosan/pshRNA plasmid nanoparti- cles were synthesized by means of a complex coacervation technique and transfected into A2780/TS cells. The cells transfected with MDRl-targeted chitosan/pshRNA plasmid nanoparticles were experimental cells and the cells transfected with chitosan/pGPU6/GFP/Neo no-load plasmid nanoparticles served as negative control cells. Morphological features of the nanoparticles were observed under transmission electron microscope （TEM）. MDR1 mRNA expression was assessed by RT-PCR. Half-inhibitory concentration （IC50） ofpaclitaxel for A2780/TS cells was determined by MTT method. TEM showed that the nanoparticles were round-shaped, smooth in surface and the diameters varied from 80 to 120 nm. The MDR1 mRNA in the transfected cells was significantly decreased by 17.6%, 27.8% and 52.6% on the post-transfection day 2, 4 and 7 when compared with that in A2780/TS cells control （P〈0.05）. MTT assay revealed that the relative reversal efficiency was increased over time and was 29.6%, 51.2% and 61.3% respectively in the transfected cells 2, 4, 7 days after transfection and IC_50 （0.197±0.003, 0.144±0.001, 0.120±0.004） were decreased with difference being significant when compared with that in A2780/TS （0.269±0.003） cells control （P〈0.05）. It was concluded that chitosan/pshRNA plasmid nanoparticles targeting MDR1 can effectively reverse the paclitaxel resistance in A2780/TS cells in a time-dependent manner.

CONGENITAL EXPRESSION OF mdr-1 GENE IN FRESH CANCER TISSUES FROM SEVERAL HIGH-INCIDENCE NEOPLASMS WITHOUT PREOPERATIVE CHEMOTHERAPY

Objective: The purpose of the present study is to detect characteristics of primary expression of mdr 1 gene in several neoplasms which has high morbidity in clinic. Methods: 151 resected samples, which are pathologically malignant and clinically untreated before operation, were obtained from Anyang Cancer Hospital. All of them were investigated with RT PCR for the expression of mdr 1 gene and correlated each other. Besides, we evaluated the advantages of RT PCR in this study. Results: The mdr 1 gene expression rate of these 151 samples, including cancers of stomach and gastric cardia (n=51), esophagus (n=46), colorectum (n=16), breast (n=15), thyroid (n=10), lung (n=9), uterine cervix (n=4), was 33.3%, 37%, 31.3%, 13.2%, 40%, 55%, 0%, respectively. Conclusion: Compared with other methods, RT PCR for studying mdr 1 gene expression had certain advantages in simplicity, reliability, and accuracy. Overexpression of mdr 1 gene in these neoplasms suggested that cases should be distinguished before treatment according to MDR of tumor and to choose effective drugs for individual cancer patient.

EFFECTS OF NEOADJUVANT CHEMOTHERAPY ON MDR1 AND MRP GENE EXPRESSION IN PRIMARY BREAST CANCER

Objective: To investigate the effects of neoadjuvant chemotherapy on the expression of drug resistance genes, multidrug resistance-1 (MDR1) and multidrug resistance-associated protein (MRP), in patients with primary breast cancer. Methods: MDR1 and MRP expression were detected by semi-quantitative RT-PCR in 20 patients with primary breast cancer, before and after chemotherapy. Results: Before chemotherapy, MDR1 and MRP expression can be detected in 15 cases (75%) and 18 cases (90%) respectively. After chemotherapy, expression of MDR1 is not significantly different from that before chemotherapy, but expression of MRP is significantly different from that before chemotherapy. Conclusion: Expression of drug resistance gene MRP, but not MDR1, is enhanced in patients with primary breast cancer submitted to neoadjuvant chemotherapy.

荧光定量RT-PCR检测mdr-1基因表达

目的 :建立荧光定量RT PCR检测肿瘤细胞mdr 1基因表达的方法 ,了解肺癌组织中mdr 1的表达水平。方法 :建立荧光定量RT PCR方法 ,在PE770 0型检测仪上定量检测K5 6 2 /ADM耐药株和K5 6 2不耐药株细胞mdr 1基因表达水平 ,同时检测 45例初治肺部肿瘤病人组织标本。结果 :荧光定量RT PCR检测K5 6 2 /ADM耐药株和K5 6 2不耐药株细胞mdr 1基因表达 ,重复 10次实验所得结果平均分别为 (6 86± 0 6 5 )× 10 7拷贝 /μgRNA和 (8 49± 0 6 7)× 10 5拷贝 /μgRNA ,两者相差 80 8倍 ,变异系数分别为 9 5 %和 7 9%。 45例肺部肿瘤中 ,有 12例检出有mdr 1基因不同程度的表达。结论 :荧光定量RT PCR检测mdr 1基因表达方法 ,检测结果用绝对拷贝数来表示 ,定量准确可靠 ,并有利于标准的统一。有 1/4未经化疗的肺癌病人有一定水平mdr

非M3型急性白血病患者中MUC1基因和MDR1基因表达及其与临床疗效的关系

背景与目的:MUC1基因在胃癌、卵巢癌、多发性骨髓瘤、恶性淋巴瘤等肿瘤中有表达,在急性白血病患者中有较高的表达。但MUC1基因和多药耐药基因(MDR1)相互关系以及两者的表达与急性白血病治疗效果的关系尚有待探讨。本研究拟探讨MUC1基因与MDR1基因表达及其与非M3型急性白血病患者治疗效果的关系。方法:应用逆转录鄄聚合酶链反应(RT鄄PCR)法检测34例初治非M3型急性白血病患者MUC1和MDR1的表达,并观察两种基因表达及其与临床疗效的关系。结果:34例初治非M3型急性白血病患者中MUC1基因阳性率为50%,MDR1基因阳性率为29.4%。MUC1基因阳性患者的MDR1阳性率为52.9%,明显高于MUC1阴性者的5.9%(P=0.003)。MUC1基因阴性者完全缓解(CR)率达94.1%,阳性患者CR率52.9%,两组有显著性差异(P<0.05);MDR1基因阴性者CR率为91.7%,明显高于阳性患者的50.0%(P<0.05)。MUC1基因和MDR1基因均阳性者CR率为55.6%,MUC1基因和MDR1基因均阴性者16例,全部获得CR。结论:非M3型急性白血病MUC1基因阳性者MDR1基因表达率较高,MUC1基因及MDR1基因均为阴性者治疗缓解率高。提示联合检测MUC1基因和MDR1基因对判断初治非M3型急性白血病的疗效有良好的预测作用,可作为临床判断疗效的一项有意义的指标。

RNAi对白血病细胞mdr-1基因和多药耐药表型的影响

目的:探讨RNA干扰技术(RNAi)对慢性粒细胞白血病急变细胞系K562/AO2细胞mdr1基因的抑制和耐药表型的逆转作用。方法:选择合成封闭mdr-1基因的小干扰序列(si-MDR1),以1个碱基突变的si-MDR1-mut为对照序列,在脂质体介导下转染至K562/AO2细胞系。RT-PCR和Western blot检测mdr1 mRNA及P-gp蛋白水平,流式细胞术分析细胞内柔红霉素(daunorubicin,DNR)积累量,并以四甲基唑蓝快速比色法(MTT)反映K562/AO2对阿霉素、长春新碱、足叶乙甙药物敏感性的变化。结果:实验证实该序列能高效封闭K562/AO2细胞内mdr-1基因表达,增加细胞内化疗药物DNR积累量,增强K562/AO2细胞对阿霉素、长春新碱、足叶乙甙的敏感性。结论:RNAi可以通过抑制mdr1基因表达,逆转K562/AO2细胞耐药表型。

初发及复发转移大肠癌患者外周血MDR-1基因表达的研究

目的 :检测初发及复发转移大肠癌患者外周血中多药耐药基因 (MDR 1)的表达 ,探讨其与病理类型及化疗疗效的关系。方法 :应用逆转录多聚酶链反应 (RT -PCR)法对 5 6例初发大肠癌及 4 0例经术后辅助化疗后复发、转移大肠癌患者的外周血进行检测 ,并与其病理类型及化疗疗效作对比研究。结果 :5 6例初发大肠癌患者外周血中MDR 1阳性表达率为2 7 2 % ,与病理类型无显著相关 (P >0 0 5 ) ;但与肠系膜淋巴结转移密切相关 ,有淋巴结转移者阳性表达率显著高于无淋巴结转移者 (P <0 0 5 ) ;4 0例化疗后复发、转移患者外周血MDR 1阳性表达率为 72 5 % ,与初发大肠癌患者的MDR 1阳性表达率相比差异有显著性 (P <0 0 5 ) ,且MDR 1的表达与化疗疗效呈负相关 ,MDR 1阳性表达者化疗疗效明显低于阴性表达者(P <0 0 5 )。结论 :大肠癌存在先天性和获得性多药耐药性 ;检测外周血MDR 1表达情况可以帮助预测化疗疗效 ,对制定临床化疗方案有指导意义。

急性白血病患者bcl-2和bax基因表达的临床意义及其与mdr-1基因表达的关系

细胞凋亡受抑作为肿瘤细胞的耐药机制 ,是急性白血病 (AL)预后不良的原因之一。bcl 2家族是目前最受重视的调控细胞凋亡的基因家族 ,本研究为探讨bcl 2和bax基因在急性白血病表达的意义 ,应用逆转录 聚合酶链反应 (RT PCR)方法测定 70例初治AL患者及 2 0例正常人的bcl 2 ,bax ,mdr 1基因mRNA水平的表达 ,用流式细胞术检测其蛋白表达。结果表明 ,bcl 2和bax基因在AL患者广泛表达 ,bcl 2mRNA平均表达水平明显高于正常对照 (1.4 6vs 0 .71,P <0 .0 5 )。bcl 2和bax基因表达及bax bcl 2比值与AL患者的年龄、性别、血小板计数、血红蛋白水平、骨髓原始细胞百分率、FAB分型和S +G2 M %均未发现相关。Bcl 2蛋白表达 (34.6 %vs 6 9.2 %,P <0 .0 5 ) ,bax bcl 2mRNA比值 (37.1%vs 82 .9%,P <0 .0 1)决定AL对化疗的敏感性 ,与ALCR率密切相关。bax bcl 2mRNA比值还是影响总生存期的因素。bcl 2与bax基因表达和mdr 1表达两者无相关关系。

选择性COX-2抑制剂塞来昔布抑制B细胞淋巴瘤细胞株MDR-1及Bcl-2的mRNA表达并增强表柔比星的抗肿瘤作用

背景与目的:部分非霍奇金淋巴瘤(non-Hodgkin’s lymphoma,NHL)具有高表达环氧合酶-2(cyclooxygenase-2,COX-2)的特征,而后者与P-糖蛋白及Bcl-2表达相关,可能导致NHL对化疗耐药。本研究旨在探讨B细胞淋巴瘤细胞株中COX-2的表达以及选择性COX-2抑制剂塞来昔布增强淋巴瘤细胞对表柔比星抗肿瘤效应的敏感性及其可能机制。方法:用荧光定量PCR(q RT-PCR)及蛋白[质]印迹法(Western blot)分别检测Raji、Jeko-1和Namalwa等淋巴瘤细胞株以及正常人外周血B细胞的COX-2表达;以梯度浓度的塞来昔布作用于淋巴瘤细胞株,CCK-8方法检测细胞增殖的抑制程度,q RT-PCR检测各细胞株MDR-1 mRNA及Bcl-2 mRNA表达的变化;表柔比星单独或联合不同浓度的塞来昔布处理Raji细胞株72 h后,CCK-8方法分析塞来昔布对表柔比星的增敏作用。结果:各淋巴瘤细胞株及正常对照外周血B细胞均不表达COX-2。塞来昔布单药即可对各淋巴瘤细胞株产生程度不同的抗增殖效应;随着塞来昔布作用浓度的增加,除Jeko-1细胞不表达MDR-1外,其余细胞株MDR-1 mRNA及Bcl-2 mRNA表达水平逐渐下降;塞来昔布明显增强表柔比星对Raji细胞的抗肿瘤活性,两者之间具有协同作用。结论:选择性COX-2抑制剂塞来昔布下调B细胞淋巴瘤细胞株的MDR-1 mRNA及Bcl-2 mRNA水平,并且增强表柔比星对淋巴瘤细胞的抗肿瘤效应。

初发及复发转移大肠癌组织与外周血MDR-1基因表达相关性研究

目的 探讨初发及复发转移大肠癌组织与外周血MDR 1基因表达的相关性。方法 采用RT PCR方法分别检测了 5 6例初发大肠癌组织及外周血和 4 0例术后化疗的复发转移大肠癌病灶组织及外周血的MDR 1表达情况。结果 无论是组织中 ,还是外周血中经过化疗的大肠癌患者MDR 1的阳性表达率均明显高于初发大肠癌患者 ,统计学上有显著性差异 (P <0 .0 5 )。结论 可以用外周血代替癌组织来检测MDR

RNAi抑制NANOG表达对肝癌细胞HepG2中MDR1表达及阿霉素敏感性的影响

目的探讨抑制NANOG表达对肝癌细胞HepG2中多药耐药基因1(multidrug resistance gene 1,MDR1)表达及阿霉素敏感性的影响。方法将靶向NANOG基因的特异性siRNA转染肝癌细胞HepG2,Real-time PCR和Western blot检测siRNA沉默NANOG基因后NANOG、MDR1 mRNA和蛋白的表达,平板克隆形成实验检测沉默NANOG基因后对细胞增殖能力的影响,流式细胞术检测沉默NANOG基因后对细胞周期的影响,CCK-8法检测沉默NANOG基因后HepG2细胞对阿霉素的敏感性情况。结果靶向NANOG基因特异性siRNA转染肝癌细胞HepG2后,能有效抑制NANOG mRNA和蛋白表达,与Mock组比值分别为(0.32±0.05)和(0.38±0.08);与Mock组比较,沉默NANOG基因后,细胞克隆形成率下降[(8.51±3.63)%vs(17.13±2.24)%,P<0.05],进入G0/G1期的细胞比例增多[(75.33±8.21)%vs(57.81±5.05)%,P<0.05],HepG2细胞对阿霉素的敏感性增强(P<0.05),HepG2细胞内MDR1 mRNA和蛋白表达下降,与Mock组比值分别为(0.35±0.06)和(0.41±0.08)。结论抑制NANOG表达可引起肝癌细胞HepG2中MDR1的表达下调并增强细胞对阿霉素的敏感性。

MDR1 C1236T、G2677T/A、C3435T的基因多态性对中国汉族肾移植患者环孢素药动学的影响(英文)

目的探讨中国汉族人中肾移植患者的多药耐药基因（MDR1）外显子exon12 C1236T、exon21 G2677T／A、exon26 C3435T的单核苷酸多态性对免疫抑制剂环孢素（CsA）药动学的影响。方法采用聚合酶联反应和限制性内切片段长度多态性（PCRRFLP）的方法对89例肾移植术后的患者进行MDR1基因分型。单克隆抗体荧光免疫偏振法测定患者术后CsA的谷浓度（c0）及服药后2h浓度（c2）。比较不同基因型之间CsA浓度剂量比值的差异。结果在89例肾移植患者中，等位基因1236T、2677T、2677A、3435T突变频率分别为66％、43％、18％和37％。肾移植术后1mo内，G2677T／A基因多态性与CsA的药动学有相关性，2个等位基因都发生突变的患者，其剂量校正c0，在术后1～7d、8～15d和16～30d比野生型分别提高51％（P=0．005）、32％（P=0．002）和63％（P〈0．001）。在术后16～30d，无论携带有1个或2个突变等位基因的患者，剂量校正c2都要比野生型患者高26％（P=0．007）和19％（P=0．041）。C1236T的剂量校正c0在术后8～15d和16～30d各基因型之间差异显著，但以CC型与CT型差异最为显著，而CC型与TT型在16—30d，则差异无统计学意义（P〉0．05）。C3435T的不同基因型之间，剂量校正c0、c2差异无统计学意义（P〉0．05）。结论在中国汉族肾移植患者中，MDRI的exon12 C1236T和exon21 G26771A的单核苷酸多态性与移植术后1mo内CsA的药动学有相关性。但把这种相关性应用在在临床上，对MDR1进行遗传学检测，以优化CsA的剂量，尚待进一步的研究。

人多药耐药基因1(mdr1)的克隆及重组腺病毒制备

目的:构建表达多药耐药基因1(MDR1)的重组腺病毒表达系统。方法:用基因工程技术将多药耐药基因1的cDNA亚克隆至穿梭质粒pAdTrack-CMV上,然后在细菌内与pAdEasy同源重组,经脂质体转染293细胞包装、扩增腺病毒颗粒。将重组腺病毒Ad5-mdr1感染小鼠单个核细胞,通过荧光显微镜及流式细胞仪进行检测。结果:酶切鉴定及PCR结果证明多药耐药基因重组腺病毒载体构建成功,构建的人多药耐药基因1(mdr1)重组腺病毒载体的效价达到8.3×1011pfu/ml。对小鼠单个核细胞的感染效率可达10%～15%,转染小鼠单个核细胞细胞48h后,可检测到mdr1基因的表达。结论:成功构建了表达多药耐药基因1的重组腺病毒载体,为后续对mdr1的相关研究创造了条件。

mdr1基因在多药耐药相关的几种人胃癌细胞系的表达

目的探讨mdr1在多药耐药相关的几种人胃癌细胞系中的转录、翻译、P-gp功能变动趋势。方法培养SGC7901/VCR(人胃癌多药耐药细胞亚系)、SGC7901和BGC823(人胃腺癌细胞系)于RPMI1640,用RT-PCR和原位杂交检测mdr1mRNA的表达,用免疫印迹和免疫组化检测P-gp的表达,用流式细胞仪检测阿霉素在细胞内的蓄积。结果半定量RT-PCR显示,SGC7901/VCRmdr1和β-actin吸收峰面积之比为5.63,SGC7901为0.61,BGC823为0.85。杂交信号呈紫蓝色颗粒,分布于胞质。免疫印迹显示SGC7901/VCRP-gp的表达最强,SGC7901最弱。P-gp阳性呈棕黄色颗粒,位于细胞膜上。SGC7901中,少数细胞P-gp表达极强。SGC7901/VCR平均光密度为(1.8310±0.8401),SGC7901为(0.3590±0.2512),BGC823为(0.6260±0.4996)(P<0.05)。SGC7901/VCR阿霉素特异荧光强度为(6.59±50.30),SGC7901为(35.88±14.55),BGC823为(27.44±7.06)(P<0.001)。结论在多药耐药相关的人胃癌细胞系SGC7901/VCR、SGC7901和BGC823中,mdr1基因均表达,P-gp具有药物外排功能,SGC7901/VCR的mdr1表达最强,SGC7901最弱,BGC823居中。