多源耐药基因表达水平的检测在儿童白血病中的临床意义

应用逆转录ＰＣＲ结合同位素定量分析，对３２例儿童白血病患者的多源耐药基因表达水平进行了研究。结果显示，初发病人的表达均较低，复发病人表达较高，缓解期病人表达程度介于两者之间，为探讨多源耐药基因表达水平与临床化疗之间的相关性及逆转克隆多源耐药性药物的应用，提供了一定的理论依据。     

原发性肝细胞癌肺耐药蛋白LRP基因表达及其意义(英文)

目的研究肺耐药蛋白 LRP 基因在原发性肝细胞癌(HCC)中产生的多药耐药机制及其表达与 HCC 的临床病理关系,对甲胎蛋白(AFP)的影响和术后预后的意义。方法采用 S-P 免疫组织化学法和原位 PCR 技术对54例未化疗的 HCC,24例 HCC 癌旁和12例肝炎后肝硬化存档石蜡包埋组织中 LRP 基因编码的 LRP 和 mRNA LRP 的表达进行检测,对术后24例2周 AFP 阳性的 HCC 病人进行术后化疗,分析 LRP 基因表达与 AFP 变化关系。所有术后病人进行化疗和随访。结果 LRP 和 mRNA LRP 在三种组织中的阳性表达率分别为61.1%,33.3%,25.0%和75.9%,37.5%,33.3%,HCC 组织中 LRP基因表达显著高于其他组织(P<0.05)。LRP 基因表达与 HCC 的分化程度有关(P<0.05),与 HCC 病人的年龄、性别、肿瘤的大小等临床病理资料无关(P>0.05)。LRP 基因表达阳性组病人术后化疗 AFP 有效率显著低于 LRP 基因表达阴性组病人(P<0.05)术后随访 LRP 基因表达阴性组病人平均生存时间长于阳性组病人,但无显著性关异(P<0.05)。结论 HCC 多药耐药(MDR)与 LRP 基因表达有关,HCC 耐药起源于内源性 MDR,LRP 基因可作为临床化疗耐药指标,检测 LRP 基因表达对化疗耐药具有指导意义,有助于 HCC 个体化疗方案制订,并为 MDR 逆转提供依据。LRP 基因表达与 PHC 的分化程度有关(P<0.05),但 LRP 基因表达可能与病人的预后无关。     

急性白血病多药耐药相关蛋白基因的表达

为研究急性白血病（ＡＬ）多药耐药相关蛋白（ＭＲＰ）基因表达与临床耐药的关系，应用半定量的逆转录多聚酶链反应，检测了６５例ＡＬ患者骨髓细胞和１５例正常人外周血单个核细胞中ＭＲＰ基因的表达。以ＭＲＰ／β２Ｍ评价ＭＲＰ的表达水平，将ＭＲＰ／β２Ｍ≥０．３表达为ＭＲＰ＾＋。结果发现复发难治组ＭＲＰ的平均表达水平及阳性率最高，与正常对照组、初治组、长期生存组的ＭＲＰ平均表达水平及阳性率均有显著性差异（Ｐ〈０     

急性非淋巴细胞性白血病患者乳腺癌耐药蛋白基因表达及其临床意义

目的：探讨急性非淋巴细胞性白血病(ANLL)患者乳腺癌耐药蛋白(BCRP)基因表达与临床耐药的关系。方法：应用半定量反转录—聚合酶链反应(RT-PCR)并以β2微球蛋白(β2-MG)作内对照，检测了36例ANLL患者及10例非恶性血液病对照组患者BCRP基因的表达，将BCRP／β2-MG≥0.5定为BCRP阳性。结果：BCRP基因在急性白血病中，阳性表达高，表达水平差别较大，由低到高依次为：对照组、完全缓解组、初治敏感组和临床耐药组。其中临床耐药组BCRP基因表达水平显著高于对照组、完全缓解组(P值分别为＜0.025，P＜0.05)；初治敏感组高于对照组(P＜0.05)。ANLL BCRP基因表达似与FAB分型无关，但与常用髓系单抗有关(P＜0.05)。结论：BCRP基因在急性白血病中阳性表达率较高，BCRP基因过度表达可能导致ANLL临床耐药，是ANLL患者预后的重要不利因素。     

肝癌多药耐药细胞株的建立及其多药耐药机理的研究

 为建立人肝癌多药耐药细胞株并研究其多药耐药的机理，本文应用BEL－7402细胞株，通过不断提高培养液中阿霉素（Doxorubicin）的浓度，长期筛选培养，得到肝癌多药耐药株BEL7402/DoX。经MTT法检测BEL－7402对长春新碱（VCR）等8种抗癌药的抗性提高了27－1100倍不等。以流式细胞技术检测了此细胞株表面MDR1蛋白P－gp、多药耐药相关蛋白MRP及谷胱甘肽硫转移系统（GSH/GST）的表达；用RT－PCR方法检测了MDR及MRP基因表达水平。发现BEL7402/Dox细胞表面P－gp表达为93.5～97.4％；MRP的表达为84.7～90.2％；RT－PCR证实此细胞株中有MDR及MRPmRNA的高表达；未发现GSH/GST的表达升高。     

多药耐药基因在大肠癌中的检测及其临床意义

我们利用逆转录聚合酶链反应技术定量分析了５４例大肠癌患者多药耐药基因表达水平，探讨其与临床化疗的相关性。初步检测结果表明：大肠癌化疗疗效与ＭＤＲＩ的表达水平有关，未经化疗的患者ＭＤＲＩ呈低水平表达；化部后的患者ＭＤＲＩ均呈高水平表达，而且随着化疗疗程的增加ＭＤＲＩ的表达水平有增加的趋势。     

MDRI基因在卵巢癌组织中的表达及其临床意义

目的 检测多药耐药基因MDR1 mRNA在卵巢癌组织中的表达及其临床应用价值。方法 选择卵巢癌组织30例、卵巢良性肿瘤组织30例、正常卵巢组织30例。采用RP－PCR复合定量技术检测卵巢癌组织中的耐药相关基因MDR1 mRNA的表达水平及分析其表达与临床化疗的相关性。结果 正常卵巢组织不表达MDR1基因;卵巢良性肿瘤组织MDR1基因表达率为10．0％;卵巢癌组织表达率为73．3％,其中高表达率占77．3％。卵巢癌组织中MDR1基因表达与卵巢良性肿瘤的比较,有非常显著性差异（P＜0．01）。卵巢癌术前化疗组MDR1基因表达率为83．3％;术前末化疗组MDR1基因表达率为58．3％,2组比较无显著性差异（P＞0．05）。定量分析表明化疗可以诱导MDR1基因表达水平增高,与非化疗组比较有非常显著性差异（P＜0．01）。结论 MDR1基因表达与卵巢癌有关。MDR1表达与卵巢癌化疗与否无关,但化疗可诱导MDR1基因表达水平增高。因此检测MDR1基因表达水平的变化可以预测继发耐药性。在判断卵巢癌临床用药时,检测MDR1耐药相关基因的表达情况可得到一定的耐药信息,对临床化疗方案的制定有较大的应用价值。     

加热能明显抑制肿瘤细胞多药耐药基因的表达

加热能明显抑制肿瘤细胞多药耐药基因的表达宋燕爽，刘洪隐，王立梅，杨毅，赵文华天津市肿瘤研究所放射生物室（天津市３０００６０）热疗在肿瘤治疗上的应用已有较长的历史，然而加热对细胞耐药性改变的分子生物学机理方面的研究报道甚少。作者用抗多药耐药基因表达蛋白...     

Expression of multidrug resistance-associated protein (MRP), MDR1 and DNA topoisomerase II in human multidrug-resistant bladder cancer cell lines.

The acquisition of the multidrug resistance phenotype in human tumours is associated with an overexpression of the 170 kDa P-glycoprotein encoded by the multidrug resistance 1 (MDR1) gene, and also with a 190 kDa membrane ATP-binding protein encoded by a multidrug resistance-associated protein (MRP) gene. Human bladder cancer is a highly malignant neoplasm which is refractory to anti-cancer chemotherapy. In order to understand the mechanism underlying multidrug resistance in bladder cancer, we established three doxorubicin-resistant cell lines, T24/ADM-1, T24/ADM-2 and KK47/ADM, and one vincristine-resistant cell line, T24/VCR, from human bladder cancer T24 and KK47 cells respectively. Both T24/ADM-1 and T24/ADM-2 cells which had elevated MRP mRNA levels showed both a cross-resistance to etoposide and a decreased intracellular accumulation of etoposide. T24/VCR cells which had elevated levels of MDR1 mRNA and P-glycoprotein but not of MRP mRNA, showed cross-resistance to doxorubicin. On the other hand, KK47/ADM cells, which had elevated levels of both MRP and MDR1 mRNA and a decreased level of topoisomerase II mRNA, were found to be cross-resistant to etoposide, vincristine and a camptothecin derivative, CPT-11. Our present study demonstrates a concomitant induction of increased levels of MRP mRNA, decreased levels of topoisomerase II mRNA and decreased drug accumulation during development of multidrug resistance in human bladder cancer cells. The enhanced expression of the MRP gene is herein discussed in a possible correlation with the decreased expression of the topoisomerase II gene.     

Expression and clinical significance of multidrug resistance gene and multidrug resistance-associated protein gene in acute leukemia

Multidrugresistance(MDR)remainsamaj0rcauseoffailureinthechemotherapeutictreatment0facuteleukemia(AL).ClassicalMDRphenotypeisduet0overexpressionofmembrane-b0undglycoprotein(Pl7O)encodedbymultidrugresistancegene(mdrl).However,lowP-glycoproteinlevelswerefrequentlyfoundinc1inicallydrug-resistantleukemia,andl0r2indicatedthatoverexpression0fthemdrlgenecann0tbeacc0untedforallcasesofdrugresistanceinleukenda.Recently,multidrugresistance-ass0ciatedprotein(MRP)genewasfoundt0beassociatedwithdrug-res…     

Reversal effect of Raf-1/Mdr-1 siRNAs co-transfection on multidrug resistance in KBv200 cell line

Multidrug resistance (MDR) is a major barrier for chemotherapy of many cancers. Mdr-1 plays a key role in the development of MDR as extensively verified. However, the role of Raf-1 overexpression in the development of multidrug resistance in human squamous carcinoma (KBv200) cells remains largely unknown. The aim of this study was to investigate the correlation of Raf-1 overexpression with the development of multidrug resistance in KBv200 cells. Furthermore, we explored the reversal effect of Raf-1 siRNA transfection and Raf-1/Mdr-1 siRNAs co-transfection on the multidrug resistance of KBv200 cells and potential mechanism of reversing the multidrug resistance. MTT and flow cytometry assay were used to investigate the reversal effect of single transfection with either Raf-1 or Mdr-1 siRNA and double transfection with Raf-1/Mdr-1 siRNAs to vincristine of KBv200 cells. RT-PCR, immunofluorescence and Western Blot were used to detect mRNA and protein expression of Raf-1 and multidrug-resistant gene Mdr-1. The results of gene detection showed that the expression levels of both Raf-1 and Mdr-1 were greatly decreased upon Raf-1 silencing alone or in combination with Mdr-1 silencing. Raf-1 or Mdr-1 siRNA single transfection could reverse the multidrug resistance of KBv200 cells effectively. Compared with single transfection, Raf-1/Mdr-1 siRNAs co-transfection can significantly reduce IC₅₀ values and increase the apoptotic rates of KBv200 cells. The above results suggested that Raf-1 gene may be a novel target for reversing the multidrug resistance of human squamous carcinoma cells. Raf-1/Mdr-1 siRNAs co-transfection might be a promising approach to abrogate the multidrug resistance of cancer cells. The potential mechanism may be via inhibiting the multidrug-resistant gene Mdr-1 expression efficiently.     

MDR1 gene overexpression and altered degree of methylation at the promoter region in bladder cancer during chemotherapeutic treatment.

Overexpression of the multidrug resistance 1 (MDR1) gene is closely associated with the clinical outcome of hematopoietic malignancies, but the alteration of its expression during chemotherapeutic treatment and the precise mechanism underlying MDR1 gene overexpression in solid tumors remains unclear. We determined the expression and degree of methylation at the promoter of the MDR1 gene in bladder cancer. The mRNA levels of the MDR1 gene were found to be markedly enhanced, 3.5- to 5.7-fold higher in bladder cancers after chemotherapeutic treatment than those in untreated primary tumors. The MDR1 gene was overexpressed in recurrent tumors in 89% of patients who showed rerecurrence, whereas overexpression was observed in 25% of the patients without re-recurrence. A statistically significant inverse correlation existed between MDR1 expression and the methylation of 5'CpG sites at the promoter in patients with bladder cancer after chemotherapeutic treatment, with the degree of methylation at several CpG sites, rather than other specific sites, involved in this regulation. Consistent with the increase in MDR1 expression, the frequency of patients with a hypermethylated promoter decreased to 50 and 17% after intravesical and systemic chemotherapy, respectively. Thus, overexpression of the MDR1 gene might be a prognostic marker for intravesical recurrence, whereas methylation of the promoter region negatively regulates MDR1 expression and the appearance of multidrug resistance mediated by P-glycoprotein in bladder cancers.     

Intrinsic drug resistance in human kidney cancer is associated with expression of a human multidrug-resistance gene

The cloning of the cDNA for the mdr1 gene, whose expression is associated with the development of multidrug-resistance in cultured cells, has made it possible to explore the mechanism of multidrug resistance in human tumors. We have found that normal human kidney, six of eight adenocarcinomas of the kidney, and four cell lines derived from kidney adenocarcinomas express high levels of mdr1 mRNA. Two criteria suggest that primary multidrug resistance in human adenocarcinomas of the kidney results, at least in part, from expression of the mdr1 gene: (1) mdr1 mRNA levels are elevated in four unselected kidney adenocarcinoma cell lines that show a multidrug-resistant phenotype; and (2) multidrug resistance in these kidney cancer cell lines is reversed by verapamil and quinidine, agents known to reverse mdr1-associated drug resistance in cell lines selected for multidrug resistance in vitro. These results suggest that appropriate pharmacological intervention to reverse multidrug resistance might make adenocarcinomas of the kidney more sensitive to chemotherapy with agents such as Adriamycin (Adria Laboratories, Columbus, OH) and the vinca alkaloids.     

Analysis of mdr-1 Gene Expression in Human Leukemic Cells by Quantitative Competitive PCR

The ability to recognize the acquisition of multidrug resistance (MDR) in leukemia patients would improve our ability to predict the responsiveness of patients to chemotherapy. To quantitate the degree of MDR acquisition, we determined the amount of mdr-1 mRNA in leukemic cells from patients by competitive polymerase chain reaction (PCR) analysis. Twenty-one patients including 12 patients prior to treatment and nine relapsed patients with acute myelogenous or lymphoblastic leukemia were examined. The amount of mdr-1 gene expression in K562, K562/ADR₅₀₀ cells and their mixtures showed a proportional correlation between the ratio of resistant to non-resistant cells and the amount of the mdr-1 gene. Mean mdr-1 gene expression in relapsed patients was greater than that in pretreatment patients. Patients refractory to chemotherapy (NR) showed higher levels of mdr-1 gene expression than the patients who achieved complete remission (CR). Because of the wide variations in values, no statistical differences were observed between pretreatment and relapsed patients, or CR and NR patients. These results suggest that the competitive PCR technique is a reliable method to quantitatively determine mdr-1 gene expression, but it may be difficult to predict responsiveness to chemotherapy by using this technique alone.