EXPRESSION OF MULTIDRUG RESISTANCE-ASSOCIATED PROTEIN IN HUMAN GASTRIC AND RENAL CARCINOMAS

Objective The clinical signilicance of exPression of multidrug resistance- associated protein (MRP) in gastric and renal carcinoma was investigated. Methods LSAB immunohistochemistry was performed to detect eopression of MRP in the carcinoma tissues of 52 patients with gastric carcinoma and 20 cases with renal cell carcinoma. Results The positive expression rate of MRP was 38.5% (20/52) in gastric carcinoma tissues, and 60% (12/20) in renal carcinoma tissues. The expression of MRP both on cellular membrane and in cytoplasm was observed, but the expression in cytoplasm (thick granule) was more obvious. The positive expression rates of MRP in advanced gastric and renal carcinoma (Ⅲ orⅣ stage) were 60% (15/25) and 88.90% (8/9) reSPectively, which were higher than those in early lesion (Ⅰ or Ⅱ stage, 18.5% and 36.4% respectively). Furthermore, the patients with positive expression of MRP in gastric carcinoma tissues had shorter mean survival time and lower 5-year survival rate than that with negative eopression of MRP. Conclusion MRP plays an important role in the infiltration and metastasis of gastric and renal carcinoma and might contribute to the intrinsic drug - resistance in both carcinomas.

EXPRESSION AND CLINICAL SIGNIFICANCE OF MULTIDRUG RESISTANCE GENE AND MULTIDRUG RESISTANCE-ASSOCIATEDPROTEIN GENE IN ACUTE LEUKEMIA

Objective: To evaluate the expression and clinical significance of multidrug resistance gene (mdr1) and multidrug resistance-associated protein (MRP) gene in acute leukemia. Methods: The expression of mdr1 and MRP assay in 55 patients with acute leukemia (AL) by reverse transcription polymerase chain reaction (RT-PCR). Results: The mdr1 and MRP gene expression levels in the relapsed AL and the blastic plastic phases of CML were significantly higher than those in the newly diagnostic AL and controls. The mdr1 and MRP gene expression levels in the clinical drug-resistant group were significantly higher than those in the non-drug-resistant group. The complete remission (CR) rate in patients with high mdr1 expression (14.3%) was significantly lower than that with low mdr1 expression (57.5%); similarly the CR rate in patients with high MRP level was also lower than that with low MRP level. Using both high expression of mdr1 and MRP gene as the indicator for evaluating multidrug resistance (MDR), the positive predictive value and accuracy increased in comparison with single gene high expression. Conclusion: Elevated level of mdr1 or MRP gene expression might be unfavorable prognostic factors for AL patient and may be used as an important index for predicting drug-resistance and relapse in AL patient. Measuring both mdr1 and MRP gene expression would increase accuracy and sensibility of evaluating MDR in acute leukemia.

EXPRESSION OF MULTIDRUG RESISTANCE-ASSOCIATED PROTEIN (MRP) AND ITS RELATIONSHIP WITH CLINICOPATHOLOGICAL FACTORS IN NON-SMALL CELL LUNG CANCER

Objective: To investigate the relationship between the expression of multidrug resistance-associated protein (MRP) and clinicopathological factors and prognosis. Methods: The expression of MRP in 62 cases with non-small cell lung cancer (NSCLC) was detected using immunohistochemistry method. The expression of MRP in 30 cases of NSCLC and corresponding normal lung tissues were detected using immunohistochemistry and Western Blot. Results: this study of tumor tissues confirmed the plasma membrane and/or cytoplasm locations of MRP. There was apparent difference between normal lung tissues and NSCLC in MRP. The survival analysis of 62 NSCLC showed that the mean survival time of the patients with negative MRP expression was 69.8117.41 months and that of patients with positive MRP expression, 25.384.46 months. Log-rank test suggested that the difference between them was significant (P=0.0156). It was also found that in squamous cell lung cancer the statistically significant difference between the mean survival time of patients with positive MRP expression and those with negative MRP expression (P=0.0153). Multivariate Cox model analysis suggested that the survival time was significantly related to expression of MRP (P=0.035) and lymphatic metastasis (P=0.038). Conclusion: MRP expression in NSCLC is significantly higher compared with normal lung tissues. The mean survival time of patients with negative MRP was relative longer and expression of MRP was an independent factor for prognosis.

JNK1,JNK2,and JNK3 are involved in P-glycoprotein-mediated multidrug resistance of hepatocellular carcinoma cells

BACKGROUND:Multidrug resistance(MDR)is extremely common in hepatocellular carcinoma(HCC)and is a major problem in cancer eradication by limiting the efficacy of chemotherapy.Modulation of c-Jun NH2-terminal kinase(JNK)activation could be a new method to reverse MDR.However,the relationship between JNK activity and MDR in HCC cells is unknown.This study aimed to explore the relationship between MDR and JNK in HCC cell lines with different degrees of MDR.METHODS:A MDR human HCC cell line,SMMC-7721/ ADM,was developed by exposing parental cells to gradually increasing concentrations of adriamycin.The MTT assay was used to determine drug sensitivity.Flow cytometry was used to analyze the cell cycle distribution and to measure the expression levels of P-glycoprotein(P-gp)and MDR-related protein(MRP)-1 in these cells.JNK1,JNK2 and JNK3 mRNA expression levels were quantified by real-time PCR.Expression and phosphorylation of JNK1,JNK2,and JNK3 were analyzed by Western blotting.RESULTS:The MDR of SMMC-7721/ADM cells resistant to 0.05 mg/L adriamycin was mainly attributed to the overexpression of P-gp but not MRP1.In addition,these cells had a significant increase in percentage in the S phase,accompanied by a decrease in percentage in the G0/G1 phase,which is likely associated with a reduced ability for cell proliferation and MDR generation.We found that JNK1,JNK2,and JNK3 activities were negatively correlated with the degree of MDR in HCC cells.CONCLUSION:This study suggests that JNK1,JNK2,and JNK3 activities are negatively correlated with the degree of MDR in HCC cells.

Expression of multidrug resistance proteins in retinoblastoma

AIM： To elucidate the mechanism of multidrug resistance in retinoblastoma, and to acquire more insights into in vivo drug resistance.METHODS： Three anticancer drug resistant Y79 human RB cells were generated against vincristine, etoposide or carboplatin, which are used for conventional chemotherapy in RB. Primary cultures from enucleated eyes after chemotherapy（PCNC） were also prepared. Their chemosensitivity to chemotherapeutic agents（vincristine, etoposide and carboplatin） were measured using MTT assay. Western blot analysis was performed to evaluate the expression of p53, Bcl-2 and various multidrug resistant proteins in retinoblastoma cells.RESULTS： Following exposure to chemotherapeutic drugs, PCNC showed less sensitivity to drugs. No significant changes observed in the p53 expression, whereas Bcl-2 expression was found to be increased in the drug resistant cells as well as in PCNC. Increased expression of P-glycoprotein（P-gp） was observed in drug resistant Y79 cells; however there was no significant change in the expression of P-gp found between primary cultures of primarily enucleated eyes and PCNC. Multidrug resistance protein 1（Mrp-1） expression was found to be elevated in the drug resistant Y79 cells as well as in PCNC. No significant change in the expression of lung resistance associatedprotein（Lrp） was observed in the drug resistant Y79 cells as well as in PCNC.CONCLUSION： Our results suggest that multidrug resistant proteins are intrinsically present in retinoblastoma which causes treatment failure in managing retinoblastoma with chemotherapy.

Expression and significance of multi-drug resistance-associated protein 3 in different tumor cell lines

Objective To investigate the expression and meaning of MRP3 in different tumor cells. MethodsThe monoclonal antibody against MRP3 was used to identify the expression of MRP3 by flow cytometer in seven tumor cells and human embryo kidney cell lines 293T.And RT-PCR was used to detect the mRNA of MRP3 in eight cell lines. ResultsThe mRNA of MRP3 was expressed in three pancreatic carcinoma cell lines.MRP3 protein was observed in BxPC-3 and AsPC-1 cells. ConclusionMRP3 may express in different tumor in tissue-specific manner.BxPC-3 and AsPC-1 may serve as cellular models for in vitro studies on multidrug resistance of pancreatic carcinoma.

Down-regulation of extracellular signal-regulated kinase 1/2 activity in P-glycoprotein-mediated multidrug resistant hepatocellular carcinoma cells

AIM:To study the expression and phosphorylation of extracellular signal-regulated kinase(ERK)1 and ERK2 in multidrug resistant(MDR)hepatocellular carcinoma(HCC)cells.METHODS:MDR HCC cell lines,HepG2/adriamycin(ADM)and SMMC7721/ADM,were developed by exposing parental cells to stepwise increasing concentrations of ADM.MTT assay was used to determine drug sensitivity.Flow cytometry was employed to analyze cell cycle distribution and measure cell P-glycoprotein(P-gp)and multidrug resistant protein 1(MRP1)expression levels.ERK1 and ERK2 mRNA expression levels were measured by quantitative real-time PCR(QRTPCR).Expression and phosphorylation of ERK1 and ERK2 were analyzed by Western blot.SMMC7721/ADM were resistant not only to ADM,but also to multiple anticancer drugs.The P-gp expression was over 10-fold higher in HepG2/ADM cells than in HepG2 cells(8.92%±0.22%vs 0.88%±0.05%,P<0.001)and over 4-fold higher in SMMC7721/ADM cells than in SMMC7721 cells(7.37%±0.26%vs 1.74%±0.25%,P<0.001).However,the MRP1 expression was not significantly higher in HepG2/ADM and SMMC7721/ADM cells than in parental cells.In addition,the percentage of MDR HepG2/ADM and SMMC7721/ADM cells was significantly decreased in the G0/G1 phase and increased in the the S phase or G2/M phase.QRT-PCR analysis demonstrated that the ERK1 and ERK2 mRNA expression increased apparently in HepG2/ADM cells and decreased significantly in SMMC7721/ADM cells.Compared with the expression of parental cells,ERK1 and ERK2 protein expressions were markedly decreased in SMMC7721/ADM cells.However,ERK2 protein expression was markedly increased while ERK1 protein expression had no significant change in HepG2/ADM cells.Phosphorylation of ERK1 and ERK2 was markedly decreased in both HepG2/ADM and SMMC7721/ADM MDR cells.CONCLUSION:ERK1 and ERK2 activities are downregulated in P-gp-mediated MDR HCC cells.ERK1 or ERK2 might be a potential drug target for circumventing MDR HCC cells.

Effects of Hypoxia on Expression of P-gp and Mutltidrug Resistance Protein in Human Lung Adenocarcinoma A549 Cell Line

To study the effects of hypoxia on the expression of P-gp and mutltidrug resistance protein in human lung adenocarcinoma A549 cell line, and to explore the probable mechanism of hypoxia in tumor cell of MDR. The expression of hypoxia inducible factor-1α, P-gp and mutltidrug resistance protein was immunohistochemically detected by culturing human lung adenocarcinoma A549 cell under hypoxia (2 % O_2) for 24 h. After interaction with adriamycin or cisplatin under hypoxia (2 % O_2) for 24 h, the cell survival rate was detected by MTT. Our results showed that the expression of hypoxia inducible factor-1α, P-gp and mutltidrug resistance protein under hypoxia were higher than the expression under normoxia, and correlations between the expression of HIF-1α and P-gp or multidrug resistance-associated protein was observed (P<0.05). The resistance of adriamycin of A549 cell was enhanced under hypoxia. It is concluded that the resistance of tumor chemotherapy is enhanced in hypoxia. The expression of HIF-1α is obviously correlated with the expression of P-gp and mutltidrug resistance protein.

乙型肝炎肝硬化并发急性肾损伤患者血清和尿液NGAL、IGFBP7和TIMP-2水平变化及其临床意义探讨

目的 探讨乙型肝炎肝硬化并发急性肾损伤(AKI)患者血清和尿液中性粒细胞明胶酶原相关蛋白(NGAL)、胰岛素样生长因子结合蛋白7(IGFBP7)和金属蛋白酶组织抑制剂-2(TIMP-2)变化及其临床意义。方法 2020年3月~2022年12月我院收治的119例乙型肝炎肝硬化患者(并发AKI者38例,其中1期15例、2期14例和3期9例)和54例健康体检者,采用ELISA法检测血清NGAL水平及尿液NGAL、IGFBP7和TIMP-2水平。应用Cox单因素和多因素Logistic回归分析影响乙型肝炎肝硬化并发AKI的危险因素。结果 AKI组血清NGAL水平及尿液NGAL、尿液TIMP-2和IGFBP7水平分别为(371.7±60.2)μg/L、(59.7±7.3)μg/L、(3.3±0.6)ng/mL和(98.3±19.5)ng/mL,显著高于肝硬化组【分别为(82.3±15.7)μg/L、(10.7±2.5)μg/L、(2.4±0.5)ng/mL和(85.0±18.2)ng/mL,P<0.05】或健康人【分别为(46.5±10.9)μg/L、(7.9±1.2)μg/L、(0.7±0.1)ng/mL和(16.1±3.7)ng/mL,P<0.05】;AKI 3期患者血清NGAL水平及尿液NGAL、尿液TIMP-2和IGFBP7水平分别为(552.7±63.5)μg/L、(81.9±13.7)μg/L、(4.0±0.7)ng/mL和(110.4±15.1)ng/mL,显著高于1期患者【分别为(249.5±50.7)μg/L、(45.7±11.9)μg/L、(2.8±0.6)ng/mL和(90.3±10.9)ng/mL,P<0.05】或2期患者【分别为(386.3±59.8)μg/L、(60.4±9.5)μg/L、(3.4±0.7)ng/mL和(99.1±12.7)ng/mL,P<0.05】;本组并发AKI患者90 d生存率为57.9%;死亡组Child-Pugh C级、AKI 3期、肝性脑病、感染和上消化道出血患者占比显著高于生存组,血清NGAL水平及尿液NGAL、尿液TIMP-2和IGFBP7水平也显著高于生存组(P<0.05);多因素分析发现,Child-Pugh C级、AKI 3期、肝性脑病和上消化道出血及尿液NGAL和IGFBP7水平升高为乙型肝炎肝硬化并发AKI患者死亡的危险因素(P<0.05)。结论 乙型肝炎肝硬化并发AKI患者血清NGAL水平及尿液NGAL、TIMP-2和IGFBP7水平变化与病情严重程度有关,且尿液NGAL和IGFBP7水平显著升高为短期死亡的危险因素。

FTO调控FBXW7的m6A甲基化修饰促进宫颈癌放化疗抵抗的机制研究

目的探讨肥胖相关蛋白(obesity-associated protein,FTO)和F框/WD-40域蛋白7(F-box and WD-40 domain protein 7,FBXW7)在宫颈鳞状细胞癌(cervical squamous cell carcinoma,CSCC)放化疗抵抗中的作用.方法实时荧光聚合酶链反应(real-time polymerase chain reaction,RT-PCR)和Western印迹检测CSCC细胞中FTO和FBXW7表达.TCGA(The Cancer Genome Atlas)数据分析FTO和FBXW7表达及相关性.在CSCC细胞中过表达FTO,免疫沉淀检测FBXW7的mRNA的m6A表达变化.四甲基偶氮唑盐比色法[3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide,MTT]检测FTO和FBXW7在CSCC细胞放化疗抵抗中的作用.结果与人正常宫颈上皮细胞(HUCEC)比较,FTO和FBXW7在CSCC细胞(SiHa,c-33a)中弱表达(P<0.05);FTO调控FBXW7的mRNA的m6A甲基化水平.过表达FTO的CSCC细胞在经过照射和顺铂处理后,细胞存活比例下降,放化疗抵抗减轻(P<0.05);而在此基础上抑制FBXW7,治疗后的细胞存活比例增加,诱导了CSCC放化疗抵抗(P<0.05).结论FTO可以去除FBXW7的m6A甲基化修饰,上调FBXW7的表达,抑制CSCC对放化疗的抵抗.FTO对CSCC恶性表型的影响是通过FBXW7实现的.

多药耐药相关蛋白转运体在药物性肝损伤中的作用研究进展

肝脏是人体新陈代谢最旺盛的器官,也是体内多种药物的解毒器官。当长期或过量使用药物时会增加药物性肝损伤(DILI)的风险。多药耐药相关蛋白(MRPs)是位于细胞膜上的功能蛋白,可转运多种药物,在DILI中发挥重要作用。MRPs功能的抑制、缺失是药物肝毒性产生的重要原因。本文对MRPs的结构、表达部位及功能进行归纳,并对MRPs与DILI的关系及其改善DILI的机制进行总结,期望更好地了解MRPs转运体与DILI的关系,为后续防治DILI提供参考。

mrp反义RNA逆转胃癌细胞系SGC7901对VCR的耐受性

目的 :探讨以多药耐药相关蛋白 (MRP)作为靶分子进行胃癌多药耐药基因治疗的可行性。方法 :采用已构建成功的mrp反义RNA真核载体pcDNA Amrp转染胃癌细胞系SGC790 1,用G418抗性筛选出稳定细胞克隆 ,命名为M SGC790 1;用32 P标记的寡核苷酸探针打点杂交检测M SGC790 1细胞中mrpmRNA表达的变化 ;从细胞生长曲线中 ,观察M SGC790 1细胞生长速度的变化 ;经 0 .0 0 5 μg/ml的长春新碱 (VCR)处理 1月后 ,行流式细胞术检测M SGC790 1细胞周期的改变 ;同时 ,行MTT法检测M SGC790 1对VCR的IC50 值 ;最后 ,行Habit法检测M SGC790 1中谷胱苷肽S 转移酶 (GST)活性。结果 :①M SGC790 1细胞的mrpmRNA表达的阳性信号明显较对照组弱。②M SGC790 1细胞生长速度与对照组无明显差异 (P >0 .0 5 )。③M SGC790 1生长明显阻滞于S期 (P <0 .0 5 )。④M SGC790 1对VCR的IC50 值显著降低 (P <0 .0 5 )。⑤M SGC790 1中GST活性与对照组相比无明显差异 (P >0 .0 5 )。结论

汉防己甲素与5-溴汉防己甲素逆转耐药机制与降低MRP7表达水平有关(英文)

本研究的目的是探索汉防己甲素(Tet)与5-溴汉防己甲素(BrTet)逆转耐药的机制是否与调节多药耐药相关蛋白7(MRP7)表达水平有关。采用MTT法检测柔红霉素(DNR)对人白血病敏感细胞株K562与人白血病耐药细胞株K562/A02细胞增殖的抑制作用,计算半数抑制浓度(IC50)及耐药倍数。将细胞分组,加入BrTet、Tet,用实时PCR法检测细胞MRP7 mRNA表达,Western bolt法检测细胞MRP7蛋白和P-糖蛋白(P-gp)的表达,流式细胞术检测细胞内DNR蓄积。结果表明:K562/A02对DNR的耐药倍数为23.65倍。分别加入1μmol/L Tet与2.0μmol/L BrTet后,K562/A02细胞的MRP7 mRNA相对表达水平分别降低至2%和12%,MRP7蛋白表达降低了53.2%与83.7%,P-gp表达分别下调58.47%与52.20%;1.0μmol/L Tet与2.0μmol/L BrTet分别使K562/A02细胞内DNR提高了94.32%与271%。结论:BrTet与Tet均可逆转耐药,其逆转机制除了抑制P-gp的表达之外,还可能与抑制MRP7的表达,增加肿瘤细胞内抗肿瘤药物浓度有关。在相同摩尔浓度下,Tet与BrTet对MRP7表达的下调作用无显著性差异。

多药耐药相关蛋白在阿霉素诱导人肝癌细胞SMMC-7721耐药性产生中的作用及机理

目的 动态观察阿霉素 (ADM )诱导肝癌细胞SMMC 772 1耐药性的产生 ,了解多药耐药相关蛋白 (MRP)在其耐药机理中的作用。方法 分别用逐步提高培养基中ADM的浓度诱导SMMC 772 1细胞和用含不同ADM浓度的培养基直接短期培养SMMC 772 1细胞的方法 ,诱导细胞产生耐药性 ,绘制剂量反应曲线 ,确定细胞耐药倍数 ,RT PCR法测定细胞MRPmRNA的表达水平 ,流式细胞仪检测细胞内柔红霉素 (DNR)的浓度。结果 随着培养基中ADM浓度的逐步提高 ,MRPmRNA的表达也逐渐增强 ,细胞内DNR浓度明显下降 ,SMMC 772 1细胞的耐药性逐渐增加 ;用含不同ADM浓度的培养基直接培养亲代细胞后 ,虽然MRPmRNA表达明显升高 ,但细胞内DNR浓度仍维持较高水平 ,并且绝大部分细胞短期内死亡。结论 ADM可以逐步诱导肝癌细胞产生耐药性 ,其机理主要是由于MRP基因过度表达 ,其蛋白产物能明显降低细胞内化疗药物浓度 ,从而细胞获得耐药性。

粉防己碱抗人乳腺癌细胞MCF-7/TAM对三苯氧胺的耐药性研究

目的探讨粉防己碱(Tet)对耐三苯氧胺(TAM)的人乳腺癌细胞MCF-7/TAM逆转耐药效应及其机制。方法采用四甲基偶氮唑蓝(MTT)法测定Tet对MCF-7/TAM细胞的药物毒性及其逆转耐药效果;采用实时荧光定量PCR法检测Tet对MCF-7/TAM细胞多药耐药相关蛋白1(MRP1)基因影响;采用Western blot法检测MCF-7/TAM细胞MRP1蛋白变化。结果 Tet对MCF-7/TAM细胞有明显逆转耐药作用,非细胞毒性剂量(0.625μg/mL)的Tet逆转耐药倍数为2.0。Tet作用于MCF-7/TAM细胞后,能够下调MRP1基因(P<0.05)和蛋白表达水平。结论 Tet可逆转MCF-7/TAM细胞的耐药性,逆转机制可能与下调细胞的MRP1表达有关。

MCF-7/BCRP细胞系的建立及其生物学特征

目的:建立表达乳腺癌耐药蛋白(BCRP)的耐药细胞系MCF-7/BCRP。方法:提取MCF-7细胞的总RNA,设计BCRP基因上下游引物,用RT-PCR法克隆出BCRP基因全长并连接到真核表达载体pcDNA3.1穴-雪上,转染MCF-7细胞后以G418筛选细胞。采用米托蒽醌外排实验、细胞毒性实验、细胞群体倍增时间、免疫荧光法鉴定构建的耐药细胞系。结果:MCF-7/BCRP对米托蒽醌耐药指数增加至14.72;外排米托蒽醌的作用增强;细胞群体倍增时间较亲代细胞延长;MCF-7/BCRP细胞能表达一定量的BCRP。结论:MCF-7/BCRP细胞能够表达BCRP并具有BCRP的耐药表型。

急性白血病患者MRP、p170与多药耐药关系的分析

目的 :评价 p糖蛋白 ( p170 )和多药耐药相关蛋白 ( m ultidrug resistance- associated protein,MRP)表达与急性白血病患者多药耐药的关系。方法 :将急性白血病患者按治疗效果分为初治敏感组、完全缓解组和复发难治组三组 ,用免疫细胞化学结合流式细胞仪测定 p170和 MRP。结果 :p170在各型白血病中完全缓解组均低于初治和复发难治组 ,MRP在 AML 中复发难治组明显高于完全缓解组 ;复发难治组 3 5人中 2 7例有上述两或一种蛋白表达增高 ,两者均与临床耐药相关。综合分析敏感性、特异性和准确性 ,以 p170和 MRP联合评价效果最佳。结论 :急性白血病多药耐药的发生是多因素的 ,p170和

细胞外基质金属蛋白酶诱导因子在肝癌细胞7721中对多药耐药的调节作用

目的采用2种方法构建人肝癌多药耐药细胞模型,封闭其细胞外基质金属蛋白酶诱导因子(EMMPRIN)(CD147)的表达,研究其生物学特性。探讨EMMPRIN在肝癌细胞中对多药耐药的作用。方法应用人肝癌细胞株7721,采用浓度梯度诱导法和高浓度阿霉素间接诱导法构建人肝癌多药耐药细胞模型(7721/Adm1和7721/Adm2细胞),应用RNAi技术封闭7721/Adm1和7721/Adm2细胞EMMPRIN的表达,构建封闭EMMPRIN的人肝癌多药耐药细胞7721/Adm1/RNAi和7721/Adm2/RNAi细胞。用反转录-聚合酶链反应(RT-PCR)、流式细胞技术检测EMMPRIN、细胞表面多药耐药基因(MDR-1)mRNA及其表达产物的表达水平。噻唑蓝(MTT)法检测上述各细胞的多药耐药性。结果 2种多药耐药模型可用于肝癌多药耐药研究。多药耐药细胞7721/Adm1和7721/Adm2中EMMPRIN,MDR-1的表达水平较7721细胞均升高,且增加了其对多种化疗药物的耐药性。而利用RNAi封闭EMMPRIN的7721/Adm1和7721/Adm2细胞可致MDR-1表达降低,增加了其对化疗药物的敏感性。结论 EMMPRIN是参与肝癌细胞7721多药耐药且为调节多药耐药的重要分子。

蛇毒精氨酸酯酶Agkihpin抑制人肝癌SMMC-7721细胞株MRP1表达

目的:探讨蛇毒精氨酸酯酶Agkihpin对人肝癌细胞株SMMC-7721中多药耐药相关蛋白1(multidrug resistance associated protein 1,MRP1)表达的影响,并阐明Agkihpin抑制人肝癌SMMC-7721细胞活力的机制。方法:采用不同浓度的Agkihpin处理SMMC-7721细胞72 h后,应用免疫细胞化学、Western blot和RT-PCR等方法检测MRP1在SMMC-7721细胞中的转录和表达。结果:不同浓度Agkihpin作用SMMC-7721细胞72 h后MRP1表达均降低,显示Agkihpin可显著下调SMMC-7721细胞中MRP1转录和表达(P<0.05),并呈现出一定的浓度依赖效应。结论:Agkibpin能抑制人低分化肝癌细胞株SMMC-7721中MRP1的表达,并呈一定程度的浓度依赖效应,提示Agkihpin在一定程度上可用于提高肝癌细胞对化疗药物的敏感性。

T790M突变所致吉非替尼耐药肺腺癌细胞放射敏感性变化及耐药性逆转的研究

目的探讨T790M突变所致吉非替尼耐药肺腺癌细胞株PC-9/GR放射敏感性的变化情况及经射线照射后PC-9/GR吉非替尼耐药的逆转情况。方法选取吉非替尼敏感肺腺癌细胞株PC-9及T790M突变所致吉非替尼继发性耐药肺腺癌细胞株PC-9/GR。应用液相芯片法检测这两种细胞中人第10号染色体缺失的磷酸酶及张力蛋白同源的基因(PTEN)mRNA表达水平;应用免疫印迹法检测这两种细胞中磷酸化哺乳动物雷帕霉素靶蛋白(p-mTOR)、磷酸化蛋白激酶B(p-Akt)、PTEN蛋白表达水平;采用集落形成实验观察射线照射细胞的存活情况;应用四甲基偶氮唑盐(MTT)比色法检测细胞的生长抑制情况。结果 (1)PC-9/GR的PTEN mRNA及其蛋白表达水平均高于PC-9(P<0.05),而p-mTOR、p-Akt蛋白表达水平则低于PC-9(P<0.05)。(2)在不同剂量6 MV X线作用下,PC-9/GR的细胞存活分数(SF)均低于PC-9(P<0.05)。(3)在不同浓度吉非替尼作用下,射线照射的PC-9/GR的生长抑制率均高于未照射的PC-9/GR(P<0.05),半数抑制浓度(IC50)则低于未照射的PC-9/GR(P<0.05)。射线照射的PC-9/GR每一吉非替尼浓度的生长抑制率均高于未经照射的PC-9/GR(P<0.05)。结论在体外实验条件下,肺腺癌细胞株PC-9/GR的放射敏感性较其亲代PC-9升高,射线照射后的PC-9/GR在一定程度上能逆转吉非替尼的耐药。