Liposome-mediated Functional Expression of Multiple Drug Resistance Gene in Human Bone Marrow CD34^+ Cells

Summary: The expression and functional activity of multiple drug resistance (MDR1) gene in human normal bone marrow CD34+ cells was observed. Human normal bone marrow CD34+ cells were enriched with magnetic cell sorting (MACS) system, and then liposome-mediated MDR1 gene was transferred into bone marrow CD34+ cells. Fluorescence-activated cell sorter was used to evaluate the expression and functional activity of P-glycoprotein (P-gp) encoded by MDR1 gene. It was found that the purity of bone marrow CD34+ cells was approximately (91±4.56) % and recovery rate was (72.3±2.36) % by MACS. The expression of P-gp in the transfected CD34+cells was obviously higher than that in non-transfected CD34+ cells. The amount of P-gp in non-transfected CD34+ cells was (11.2±2.2) %, but increased to (23.6±2.34) % 48 h after gene transfection (P<0.0l). The amount of P-gp was gradually decreased to the basic level one week later. The accumulation and extrusion assays showed that the overexpression of P-gp could efflux Rh-123 out of cells and there was low fluorescence within the transfected cells. The functional activity of P-gp could be inhibited by 10 μg/ml verapamil. It was suggested that the transient and highly effective expression and functional activity of P-gp could be obtained by liposome-mediated MRD1 transferring into human normal bone marrow CD34+ cells.

Suppression of P-gp induced multiple drug resistance in a drug resistant gastric cancer cell line by overexpression of Fas

AIM To observe the drug sensitizing effect andrelated mechanisms of fas gene transduction onhuman drug-resistant gastric cancer cellSGC7901/VCR(resistant to Vincristine).METHODS The cell cycle alteration wasobserved by FACS.The sensitivity of gastriccancer cells to apoptosis was determined by invitro apoptosis assay.The drug sensitization ofcells to several anti-tumor drugs was observedby MTT assay.Immunochemical method wasused to show expression of P-gp and Topo Ⅱ ingastric cancer cells.RESULTS Comparing to SGC7901 and pBK-SGC7901/VCR,fas-SGC7901/VCR showeddecreasing G2 cells and increasing S cells,theG2 phase fraction of pBK-SGC7901/VCR wasabout 3.0 times that of fas-SGC7901/VCR,but Sphase fraction of fas-SGC7901/VCR was about1.9 times that of pBK-SGC7901/VCR,indicatingS phase arrest of fas-SGC7901/VCR.FACS alsosuggested apoptosis of fas-SGC7901/VCR,fas-SGC7901/VCR was more sensitive to apoptosisinducing agent VM-26 than pBK-SGC7901/VCR.MTT assay showed increased sensitization offas-SGC7901/VCR to DDP,MMC and 5-FU,butsame sensitization to VCR according to pBK-SGC7901/VCR.SGC7901,pBK-SGC7901/ VCRand fas-SGC7901/VCR had positively stainedTopo Ⅱ equally.P-gp staining in pBK- SGC7901/VCR was stronger than in SG07901,but there was little staining of P-gp in fas.SGC7901/VCR.CONCLUSION fas gene transduction couldreverse the MDR of human drug-resistant gastriccancer cell SGC7901/VCR to a degree,possiblybecause of higher sensitization to apoptosis anddecreased expression of P-gp.

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.

Transduction of Fas gene or Bcl-2 antisense RNA sensitizes cultured drug resistant gastric cancer cells to chemotherapeutic drugs

AIM To compare the expression level of Fas gene and Bcl-2 gene in gastric cancer cells SGC7901 and gastric cancer MDR (multidrug resistant) cells SGC7901/VCR, to transduce Fas cDNA and Bcl-2 antisense nucleic acid into SGC7901/VCR cells respectively, and to observe the expression of two genes in transfectants and non-transfectants as well as their drug sensitivity.METHODS Eukaryotic expression vector pBK-Fas cDNA and pDOR-anti Bcl-2 were constructed and transfected into SGC7901/VCR cells by lipofectamine, respectively. Northern blot and Western blot were used to detect the expression of mRNA and protein in SGC7901/VCR and SGC7901 cells and transfectants, and drug sensitivity of transfectants for VCR, CDDP and 5-FU was analyzed with MTT assay.RESULTS After gene transfection, 80 for Fas and 120 for antisense Bcl-2 drug-resistant clones were selected from 2×105 cells, transfection rate being 0.04% and 0.06%. Two clones of SGC7901 Fas/VCR cells and SGC7901 anti Bcl-2/VCR cells were randomly selected for further incubation. Hybridization results showed that the expression level of Fas mRNA and protein in SGC7901/VCR cells was much lower, but that of Bcl-2 mRNA and protein was higher than that in SGC7901 cells. The expression of Fas mRNA and protein in SGC7901 Fas/VCR cells was higher, and of Bcl-2 mRNA and protein was lower in SGC7901 anti Bcl-2/VCR cells than that in non-transfectants. MTT assay showed that transfectants were more sensitive to VCR, CDDP, 5-FU than non-transfectants.CONCLUSION Bcl-2 gene displayed high expression while Fas gene had low expression in drug resistant gastric cancer cells. Expression of Bcl-2 protein was effectively blocked in SGC7901 anti Bcl-2/VCR cells by gene transfection. In contrast, the expression of Fas mRNA and protein in SGC7901 Fas/VCR cells increased. Fas gene and Bcl-2 antisense nucleic acid transfection sensitized drug resistant gastric cancer cells to chemotherapeutic drugs. These results suggest cell apoptosis plays an important role in the mechanism of MDR, and enhancing apoptosis might reverse MDR.

Enhanced anticancer effect of doxorubicin by TPGS-coated liposomes with Bcl-2 siRNA-corona for dual suppression of drug resistance

Multiple drug resistance(MDR)is a tough problem in developing hepatocellular carcinoma(HCC)therapy.Here,we developed TPGS-coated cationic liposomes with Bcl-2 siRNA corona to load doxorubicin(Dox)i.e.,Bcl-2 siRNA/Dox-TPGS-LPs,to enhance anticancer effect of Dox in HCC-MDR.TPGS i.e.,d-α-tocopheryl polyethylene glycol 1000 succinate,inhibited Pglycoprotein(P-gp)efflux pump and Bcl-2 siRNA suppressed anti-apoptotic Bcl-2 protein.The Bcl-2 siRNA loaded in the liposomal corona was observed under transmission electron microscopy.The stability and hemolysis evaluation demonstrated Bcl-2 siRNA/Dox-TPGSLPs had good biocompatibility and siRNA-corona could protect the liposomal core to avoid the attachment of fetal bovine serum.In drug-resistant cells,TPGS effectively prolonged intracellular Dox retention time and siRNA-corona did improve the internalization of Dox from liposomes.In vitro and in vivo anticancer effect of this dual-functional nanostructure was examined in HCC-MDR Bel7402/5-FU tumor model.MTT assay confirmed the IC50 value of Dox was 20–50 fold higher in Bel7402/5-FU MDR cells than that in sensitive Bel7402 cells.Bcl-2 siRNA corona successfully entered the cytosol of Bel7402/5-FU MDR cells to downregulate Bcl-2 protein levels in vitro and in vivo.Bcl-2 siRNA/Dox-TPGS-LPs showed superior to TPGS-(or siRNA-)linked Dox liposomes in cell apoptosis and cytotoxicity assay in Bel7402/5-FU MDR cells,and 7-fold greater effect than free Dox in tumor growth inhibition of Bel7402/5-FU xenograft nude mice.In conclusion,TPGS-coated cationic liposomes with Bcl-2 siRNA corona had the capacity to inhibit MDR dual-pathways and subsequently improved the anti-tumor activity of the chemotherapeutic agent co-delivered to a level that cannot be achieved by inhibiting a MDR single way.

Comparison of extended spectrum β-lactamasesproducing Escherichia coli with non-ESBLsproducing E.coli:drug-resistance and virulence

The virulent factors of Escherichia coil （E.cofi） play an important role in the process of pathopoiesis. The study aimed to compare drug-resistant genes and virulence genes between extended spectrum β-1actamases （ESBLs）-producing E.coli and non-ESBLs-producing E.cofi to provide a reference for physicians in management of hospital infection. From October 2010 to August 2011,96 drug-resistant strains of E. coli isolated were collected from the specimens in Qingdao Municipal Hospital, Qingdao, China. These bacteria strains were divided into a ESBLs-producing group and a non-ESBLs-producing group. Drug sensitivity tests were performed using the Kirby-Bauer （K-B） method. Disinfectant gene, qacEAl-sull and 8 virulence genes （CNF2, hlyA, eaeA, VT1, est, bfpA, elt, and CNF1） were tested by polymerase chain reaction （PCR）. Among the 96 E.coli isolates, the ESBLs-producing E.coli comprised 46 （47.9%） strains and the non-ESBLs-producing E.cofi consisted of 50 （52.1%） strains. The detection rates of multiple drug-resistant strain, qacEAl-sull, CNF2, hlyA, eaeA,VT1, est, bfpA, elt, and CNF1 in 46 ESBLs-producing E.coli isolates were 89.1%, 76.1%, 6.5%, 69.6%, 69.6%, 89.1%, 10.9%, 26.1%, 8.7%, and 19.6%, respectively. In the non-ESBLs-producing E.cofi strains, the positive rates of multiple drug-resistant strain, qacEAl-sull, CNF2, hlyA, eaeA, VT1, est, bfpA, elt, and CNF1 were 62.0%, 80.0%, 16.0%, 28.0%, 64.0%, 38.0%, 6.0%, 34.0%, 10.0%, and 24.0%, respectively. The difference in the detection rates of multiple drug-resistant strain, hlyA and VT1 between the ESBLs-producing E.cofi strains and the non-ESBLs-producing E.cofi strains was statistically significant （P〈0.05）. The positive rate of multiple drug-resistant strains is higher in the ESBLs-producing strains than in the non-ESBLs-producing strains. The expression of some virulence genes hlyA and VT1 varies between the ESBLs-producing strains and the non-ESBLs-producing strains. Increased awareness of clinicians and enhanced testing by laboratories are required to reduce treatment failures and prevent the spread of multiple drug-resistant strains.

Clinical relationship between MDR1 gene and gallbladder cancer

BACKGROUND: The most common mechanisms of mul- tidrug resistance (MDR) in cancer cells is the expression of an energy-dependent exfflux pump. P-glycoprotein (P-gp) encoded by MDR1 gene and multidrug associated protein (MRP) are well known proteins associated with MDR. In human cancers, the MDR1 gene expression is common in patients with intrinsic and acquired MDR. It is a major therapeutic problem in cancer chemotherapy. Previously we found that the MDR of HCC is related to MRP gene ex- pression and initiates the intrinsic MDR. The aim of this study is to study the expression of MDR1 gene encoding P-gp and MDR1 mRNA in primary gallbladder carcinoma, and analyze its clinical significance. METHODS: Immunohistochemistry (IHC) S-P method and in situ polymerase chain reaction (ISPCR) were used to detect the expression of P-gp and MDR1 mRNA in 53 cases of untreated primary gallbladder carcinoma and 12 ca- ses of cholecystitis (archival paraffin-embedded tissues). RESULTS: The positive expression rates of P-gp and MDR1 mRNA in the 53 cases and 12 cases were 60.38%, 71.69% and 25.00%, 33.33%, respectively. There was a significant difference between the two groups (P<0.05). The positive expression rate of P-gp and MDRlmRNA were 69.44%, 83.33% and 41.18%, 47.06% respectively in tissues in stage of Nevin against Nevin , (P<0.05). In well, moderately differentiated gallbladder carcinoma tissues, their expressions were 79.49%, 69.23% against 50.00%, 35.71% in low, undifferentiated tissues (P<0.05). CONCLUSIONS: MDR to gallbladder carcinoma is closely related to the intrinsic MDR and it provides an important evidence to reverse the MDR by detection of the MDR1gene. Meanwhile, MDR1 gene expression in gallbladder carcinoma is correlated with some biological characteris- tics , takes part in the carcinogenesis of gallbladder tissues, and acts as a valuable biomarker of prognosis.

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.

Antiboitic Resistance of Uropathogenic Eshcherichia coli in Pateints of Hargeisa Group Hospital, Hargeisa, Somaliand

Background: Urinary tract infection is a common disease in Somaliland society. The predominant causative organism of Urinary tract infection is Escherichia coli. This research studies antibiotic resistance of uropathogenic E. coli in patients of Hargeisa Group Hospital. The study selected commonly prescribed antibiotics for urinary tract infection treatment. Methodology: Urine samples of patients were cultured to isolate causative organisms of the urinary tract infection. Chromo-agar media, CLED, and biochemical tests are applied to identify the type of bacteria. Antibiotic reactions to E. coli bacteria are measured to differentiate between sensitive and resistant drugs with the guidance of the Clinical and Laboratories Standard Institute (CLSI). Kirby Bauer disc diffusion method is applied to assess antimicrobial activity against E. coli. Data of patients such as age, sex, symptoms of UTI, previous UTI infection, and history of antibiotic use were recorded. SPSS and Microsoft Excel are applied to analyze and interpret data. Results: The predominant organism that caused urinary tract infection was Escherichia coli (55%), Klebsiella spp (15%), Candida spp (15%), Enterococcus spp (10%), Staph spp 2.5%, and Pseudomonas spp 2.5% while other 55% were negative. The study assessed antibiotic resistance of E. coli, which reported resistance to Tetracycline at (70%), Ampicillin (64%), and Cotrimoxazole (61%). The bacteria showed moderate resistance to Ceftriaxone (43.5%), Nalidixic acid (43%), and Ciprofloxacin (36%). The bacteria are sensitive to Amikacin (100%), Nitrofurantoin (96%), Levofloxacin (73%) and gentamicin (74%). Conclusion: The overall incidence of antibiotic resistance to E. coli is high because the bacteria show a percentage of resistance to each antibiotic except Amikacin which gives (100%) sensitivity. The research recommends public awareness of the risks associated with antibiotic use and periodic evaluation of antibiotic resistance to accomplish better managing urinary tract infections.

Reversal of MDR1 gene-dependent multidrug resistance using short hairpin RNA expression vectors

Background RNA interference using short hairpin RNA (shRNA) can mediate sequence-specific inhibition of gene expression in mammalian cells. A vector-based approach for synthesizing shRNA has been developed recently. Overexpression of P-glycoprotein (P-gp), the MDR1 gene product, confers multidrug resistance (MDR) to cancer cells. In this study, we reversed MDR using shRNA expression vectors in a multidrug-resistant human breast cancer cell line (MCF-7/AdrR). Methods The two shRNA expression vectors were constructed and introduced into MCF-7/AdrR cells. Expression of MDR1 mRNA was assessed by RT-PCR, and P-gp expression was determined by Western Blot and immunocytochemistry. Apoptosis and sensitization of the breast cancer cells to doxorubicin were quantified by flow cytometry and methyl thiazolyl tetrazolium (MTT) assays, respectively. Cellular daunorubicin accumulation was assayed by laser confocal scanning microscopy (LCSM). Statistical significance of differences in mean values was evaluated by Student’s t tests. P<0.05 was considered statistically significant.Results In MCF-7/AdrA cells transfected with MDR1-A and MDR1-B shRNA expression vectors, RT-PCR showed that MDR1 mRNA expression was reduced by 40.9% (P<0.05), 30.1% (P<0.01) (transient transfection) and 37.6 % (P<0.05), 28.0% (P<0.01) (stable transfection), respectively. Western Blot and immunocytochemistry showed that P-gp expression was significantly and specifically inhibited. Resistance against doxorubicin was decreased from 162-fold to 109-fold (P<0.05), 54-fold (P<0.01) (transient transfection) and to 108-fold (P<0.05), 50-fold (P<0.01) (stable transfection). Furthermore, shRNA vectors significantly enhanced the cellular daunorubicin accumulation. The combination of shRNA vectors and doxorubicin significantly induced apoptosis in MCF-7/AdrR cells. Conclusions shRNA expression vectors effectively reduce MDR expression in a sustained fashion and can restore the sensitivity of drug-resistant cancer cells to conventional chemotherapeutic agents.

Selective reversal of drug resistance in drug-resistant lung adenocarcinoma cells by tumor-specific expression of MDR1 ribozyme gene mediated by retrovirus

According to the fact that CEA gene expressed only in lung adenocarcinoma and not in normal lung cells, a retroviral vector (pCEAMR) was constructed which carried the CEA promoter coupled to MDR1 ribozyme gene. pCEAMR was introduced into drug-resistant lung adenocarcinoma cells GAOK with CEA expression and HeLaK without CEA expression; the expression of pCEAMR and drug resistance in the infected cells were analyzed in vitro and in vivo ; pCEAMR expressed only in CEA-producing GAOK cells and not in non-CEA-producing HeLa cells. The drug resistance to doxorubicin (DOX) decreased 91.5% in the infected GAOK cells and did not change in the infected HeLa cells. In nude mice, DOX could obviously inhibit the growth of the infected GAOK tumors, and had no effect on the growth of the infected HeLa cells. These results indicated that MDR1 ribozyme gene regulated by CEA promoter expressed only in human adenocarcinoma cells and reversed their drug resistance selectively. This gene-drug therapy might serve as an effective treatment method for patients with CEA-producing lung cancers which was usually refractory to conventional chemotherapy.

MDR基因及MDR基因编码产物在咽喉部恶性黑色素瘤中表达及其意义

目的 :研究多药耐药 (mnlti-drugresistance ,MDR)基因胎盘型谷胱甘肽 -S -转移酶 (GST -π)和DNA拓朴酶Ⅱ (TopoⅡ )以及MDR基因编码产物P -糖蛋白 (Pgp)、在咽喉部恶性黑色素瘤中的表达及其意义。方法 :应用链霉素亲生物素 -过氧化物酶标S -P法检测 2 8例咽喉部恶性黑色素瘤中Pgp、GST -π和TopoⅡ的表达 ,分析MDR基因及MDR基因编码产物阳性表达率与肿瘤主要临床病理特征的关系。结果 :2 8例标本中Pgp、GST -π和TopoⅡ的表达率分别为 35 .7%、5 7.1%和 4 6 .4 % ,相互间差异无显著性 (P >0 .0 5 )。Pgp、GST -π和TopoⅡ的表达与性别、年龄、肿瘤大小无明显相关 (P >0 .0 5 ) ,与AJC分级显著相关 (P <0 .0 5 )。结论 :Pgp、GST -π和TopoⅡ等多因素联合作用是咽喉部恶性黑色素瘤多药耐药的主要作用机理 ,其表达在化疗敏感性预测中具有必要性和可行性。

基因mdr1高表达多药耐药肿瘤细胞对力达霉素的药物敏感性

目的利用经药物诱导获得的mdr1基因高表达细胞株以及通过mdr1基因转染建立的稳定高表达细胞株,研究多药耐药肿瘤细胞对力达霉素(C-1027)的药物敏感性。方法构建mdr1重组真核表达质粒pcDNA3.1/mdr1,利用脂质体转染技术,获得mdr1高表达HepG2肝癌细胞。经RT-PCR、细胞荧光免疫化学及罗丹明外排实验,鉴定了细胞的mdr1表达水平和药物外排活性。MTT方法测定敏感细胞及相对应的多药耐药细胞对力达霉素等多种抗肿瘤药物的药物敏感性。结果mdr1稳定转染细胞株HepG2/mdr1、多药耐药KBv200细胞和MCF-7/ADR细胞对力达霉素的IC50值分别为(0.020±0.011)nmol.L-1,(0.24±0.20)nmol.L-1和(0.028±0.011)nmol.L-1。相对于各自的敏感细胞,多药耐药细胞HepG2/mdr1,KBv200和MCF-7/ADR对力达霉素的抗药倍数分别是1.3,6.8和1.6倍,对阿霉素的抗药倍数分别是8.8,37.2和181.3倍,对紫杉醇的抗药倍数分别是40.3,336.8和49.2倍。结论mdr1高表达的多药耐药肿瘤细胞对力达霉素仍高度敏感,未表现出抗药性。

RNA干扰技术抑制耐药细胞MDR1基因表达的研究

目的:探讨载体表达的小干扰RNA(siRNA)抑制MDR1基因的表达,并逆转卵巢癌耐药细胞多药耐药的可行性。方法:浓度梯度诱导法和人MDR1基因载体转染法建立阿霉素耐药细胞株OVCAR/AR和多药耐药亚株OVCAR/MDR细胞。脂质体介导将MDR1特异性siRNA的表达载体(pSN/mdr1a和pSN/mdr1b)转染耐药细胞,实时定量RT-PCR方法检测MDRl mRNA的表达,流式细胞术检测P-gp的表达,MTT法检测耐药细胞对化疗药的抵抗性。结果:耐药细胞OVCAR/MDR细胞MDR1 mRNA的表达高于OVCAR/AR细胞,两者均高于其亲代细胞OV-CAR-3;转染pSN/mdr1a和pSN/mdr1b可显著抑制两株耐药细胞MDR1 mRNA和P-gp的表达,OVCAR/MDR和OV-CAR/AR细胞对阿霉素抗药性的逆转率分别为79.5%和93.9%。结论:载体表达的MDR1特异性siRNA可抑制卵巢癌耐药细胞亚株MDR1基因的表达,因而增加耐药细胞对化疗药物的敏感性。

左乙拉西坦对难治性癫痫患儿外周血单个核细胞MDR1 mRNA和P-gp表达的影响

目的观察左乙拉西坦对难治性癫痫患儿外周血单个核细胞多药耐药基因1(MDR1)mRNA和P-糖蛋白(P-gp)表达的影响,并探讨其临床意义。方法选取难治性癫痫患儿50例,在原抗癫痫方案基础上添加左乙拉西坦治疗,分别于添加左乙拉西坦治疗前及治疗6、12个月,采集外周静脉血,提取单个核细胞,采用RT-PCR法检测MDR1 mRNA表达,采用Western blotting法检测P-gp表达。结果难治性癫痫患儿在添加左乙拉西坦治疗6、12个月外周血单个核细胞MDR1 mRNA与P-gp相对表达量均较添加左乙拉西坦治疗前明显降低(P均<0.05);添加左乙拉西坦治疗6、12个月外周血单个核细胞MDR1 mRNA与P-gp相对表达量比较虽无统计学差异(P均>0.05),但随着治疗时间延长,二者相对表达量有下降趋势。结论难治性癫痫患儿添加左乙拉西坦治疗能明显下调外周血单个核细胞MDR1 mRNA与P-gp表达,这为难治性癫痫治疗提供了新的思路。

Reversing drug resistance in the ovarian carcinoma cell line SKOV3/mdr1 in vitro by antisense oligodeoxynucleotides

Objective To investigate the effect of multidrug resistance gene 1 (mdr1) antisense oligodeoxynucleotides (ODNs) on reversing multidrug resistance in the drug resistant ovarian carcinoma cell line SKOV3/mdr1. Methods The ovarian carcinoma cell line SKOV3 transducted with a human multidrug resistance gene (mdr1) served as the drug resistant model (SKOV3/mdr1). The mdr1 antisense ODNs was transfected into SKOV3/mdr1 cells while mediated by lipofectamine. Reverse transcription-polymerase chain reaction (RT-PCR) was used to measure the expression and the amount of the mdr1 mRNA in the cells. The positive rate and function of the mdr1 gene product P-glycoprotein (Pgp) in the mdr1 antisense ODNs treated SKOV3/mdr1 cells were determined by flow cytometry and rhodamine 123 efflux. Drug resistance in the SKOV3/mdr1 cell line was observed by MTT assay and cell colony culture. Results The mdr1 mRNA level was decreased to about 60% of that of β-actin after mdr1 antisense ODNs treatment. The Pgp positive rate of mdr1 antisense ODNs treated SKOV3/mdr1 cells decreased from 100% to 52.6% (P<0.01). The intracellular rhodamine 123 retention was increased from 9.1% to 33.8% (P<0.01). The chemoresistance to taxol decreased to 58% of SKOV3/mdr1 with mdr1 antisense ODN treatment. Compared with SKOV3/mdr1 cells in the control group, under a certain range of drug concentrations, the number of drug resistance colonies in mdr1 antisense ODNs treated SKOV3/mdr1 cells for taxol and doxorubicin decreased by 8.6±0.8 fold and 3.1±0.6 fold, respectively. Some non-specific functions during oligodeoxyncleotide treatment was also detected. Conclusion mdr1 expression in the SKOV1/mdr1 cell line was partially inhibited after mdr1 antisense ODNs treatment at the mRNA and protein level, increasing the chemotherapy sensitivity of this drug resistant ovarian carcinoma cell line.

胃癌组织中MDR和MGMT基因表达及其相关意义

目的:检测胃癌组织多药耐药(multidrugresistance,MDR)基因和O6-甲基鸟嘌呤-DNA-甲基转移酶(O6-methylguanin-e-DNA-meyhyltransferase,MGMT)基因的表达,探讨MDR、MGMT基因表达的相关性及其在胃癌组织中的临床病理学意义。方法:应用加强型原位杂交技术通过核酸探针对76例胃癌组织进行MDR、MGMT基因检测,同时应用自动图像分析系统进行定量分析。结果:76例胃癌组织中MDR基因阳性表达率为68·4%,积分吸光度为351·5±121·4,分别高于正常组织(40·0%,168·4±68·8);MGMT阳性表达率为40·8%,积分吸光度为161·4±78·84,分别低于正常组织(60·4%,332·9±118·2)。生存时间5年以下组MDR和MGMT基因表达分别高于5年以上组,rs分别为0·250和0·287,P值分别为0·010和0·008;白细胞计数>3×109L-1组MGMT基因表达高于<3×109L-1组,rs=0·354,P=0·001;有淋巴结转移组MDR基因表达高于无淋巴结转移组,rs=0·280,P=0·004;术前化疗组MDR表达明显高于未化疗组,rs=0·300,P=0·002。结论:胃癌组织存在原发性和获得性MDR基因耐药的双重性,而MGMT基因主要是原发性,两种基因表达可能是2个相互独立的事件,在胃癌预后和骨髓抑制的判断上有一定意义。

儿童急性白血病Bcl-2基因MDR1基因表达及意义(英文)

目的 研究Bcl 2 ,MDR1基因与儿童急性白血病耐药的关系及其临床意义。方法 采用逆转录多聚酶链式反应 (RT PCR)技术 ,对 36例急性白血病患儿及 10例血小板减少性紫癜患儿 (对照 )骨髓单个核细胞中Bcl 2和MDR1基因的表达进行检测。结果 ①初治组、复发组Bcl 2基因表达明显高于对照组 ,差异均有显著性(P <0 .0 5 )。初治组、完全缓解组Bcl 2基因表达明显低于复发组 ,差异均有显著性 (P <0 .0 1)。复发组MDR1基因的表达明显高于对照组、初治组、完全缓解组 (P <0 .0 1或 0 .0 5 )。初治组与对照组间及完全缓解组与对照组间的MDR1表达差异无显著性 (P >0 .0 5 )。②Bcl 2和MDR1基因的表达与白血病临床特征如性别、年龄、初诊时白细胞数、骨髓中幼稚细胞百分数及肝、脾、淋巴结肿大程度均无显著相关性 (P >0 .0 5 )。③Bcl 2与MDR1基因之间无显著相关性 (rs=0 .30 8,P>0 .0 5 )。结论 Bcl 2和MDR1基因可能通过不同的机制导致白血病的耐药。

中药柴贝止痫汤对难治性癫痫大鼠多药耐药基因MDR1表达的研究

[目的]通过比较不同药物干预对多药耐药基因1(MDR1)的影响,观察难治性癫痫大鼠脑内MDR1mRNA的表达和分布,探讨难治性癫痫多药耐药可能的分子病理机制,及中药复方柴贝止痫汤对其表达的影响。[方法]以不同药物干预下,观察癫痫发作的平均持续时间、癫痫发作级别,以判定、分析药物的疗效。采用荧光实时定量聚合敏链反应(PCR)的方法,分析、比较多药耐药基因MDR1在各组大鼠海马和皮质部位的表达和分布。[结果]与正常组大鼠比较,各致痫组MDR1mRNA表达含量均有明显增高,具有统计学意义(P<0.05)。[结论]癫痫的反复发作可以诱导慢性难治性癫痫大鼠海马和皮质MDR1mRNA的表达,中药复方柴贝止痫汤具有一定抑制MDR1药物转运体功能。

胃癌组织mdr1基因表达的临床意义

目的探讨多药耐药基因（ｍｄｒ１基因）在人胃癌组织中的表达及其与临床病理的关系．方法应用ＲＴＰＣＲ法检测了２９例手术切除人胃癌组织中的ｍｄｒ１ｍＲＮＡ．术前未用过化疗．结果ｍｄｒ１ｍＲＮＡ的阳性率为４８３％（１４／２９），ｍｄｒ１ｍＲＮＡ的表达在肿瘤浸润浆膜者为３３３％（７／２１），明显低于未浸润浆膜者（７／８），基因的表达与年龄、性别、肿瘤大小、组织学类型、淋巴结转移及ＴＮＭ分期等无关．结论化疗前胃癌组织中ｍｄｒ１基因即存在较高的表达率，这为选用化疗药物和ＭＤＲ逆转剂提供了参考指标．ｍｄｒ１ｍＲＮＡ表达减少似与肿瘤进展相关．