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Sample records for abcb1 mdr1 expression

  1. A synonymous polymorphism in a common MDR1 (ABCB1) haplotype shapes protein function

    Fung, King Leung; Gottesman, Michael M.

    2009-01-01

    The MDR1 (ABCB1) gene encodes a membrane-bound transporter that actively effluxes a wide range of compounds from cells. The overexpression of MDR1 by multidrug-resistant cancer cells is a serious impediment to chemotherapy. MDR1 is expressed in various tissues to protect them from the adverse effect of toxins. The pharmacokinetics of drugs that are also MDR1 substrates also influence disease outcome and treatment efficacy. Although MDR1 is a well conserved gene, there is increasing evidence t...

  2. Expression of multidrug resistance markers ABCB1 (MDR-1/P-gp) and ABCC1 (MRP-1) in renal cell carcinoma.

    Walsh, Naomi

    2009-01-01

    BACKGROUND: Renal cell carcinoma patients respond poorly to conventional chemotherapy, this unresponsiveness may be attributable to multidrug resistance (MDR). The mechanisms of MDR in renal cancer are not fully understood and the specific contribution of ABC transporter proteins which have been implicated in the chemoresistance of various cancers has not been fully defined in this disease. METHODS: In this retrospective study the expression of two of these transporter efflux pumps, namely MDR-1 P-gp (ABCB1) and MRP-1 (ABCC1) were studied by immunohistochemistry in archival material from 95 renal cell carcinoma patients. RESULTS: In the first study investigating MDR-1 P-gp and MRP-1 protein expression patterns in renal cell carcinoma patients, high levels of expression of both efflux pumps are observed with 100% of tumours studied showing MDR-1 P-gp and MRP-1 positivity. CONCLUSION: Although these findings do not prove a causal role, the high frequency of tumours expressing these efflux pumps suggests that they may be important contributors to the chemoresistance of this tumour type.

  3. Beta-Amyloid Downregulates MDR1-P-Glycoprotein (Abcb1 Expression at the Blood-Brain Barrier in Mice

    Anja Brenn

    2011-01-01

    Full Text Available Neurovascular dysfunction is an important component of Alzheimer's disease, leading to reduced clearance across the blood-brain barrier and accumulation of neurotoxic β-amyloid (Aβ peptides in the brain. It has been shown that the ABC transport protein P-glycoprotein (P-gp, ABCB1 is involved in the export of Aβ from the brain into the blood. To determine whether Aβ influences the expression of key Aβ transporters, we studied the effects of 1-day subcutaneous Aβ1-40 and Aβ1-42 administration via Alzet mini-osmotic pumps on P-gp, BCRP, LRP1, and RAGE expression in the brain of 90-day-old male FVB mice. Our results demonstrate significantly reduced P-gp, LRP1, and RAGE mRNA expression in mice treated with Aβ1-42 compared to controls, while BCRP expression was not affected. The expression of the four proteins was unchanged in mice treated with Aβ1-40 or reverse-sequence peptides. These findings indicate that, in addition to the age-related decrease of P-gp expression, Aβ1-42 itself downregulates the expression of P-gp and other Aβ-transporters, which could exacerbate the intracerebral accumulation of Aβ and thereby accelerate neurodegeneration in Alzheimer's disease and cerebral β-amyloid angiopathy.

  4. Inhibition of ABCB1 (MDR1 expression by an siRNA nanoparticulate delivery system to overcome drug resistance in osteosarcoma.

    Michiro Susa

    Full Text Available BACKGROUND: The use of neo-adjuvant chemotherapy in treating osteosarcoma has improved patients' average 5 year survival rate from 20% to 70% in the past 30 years. However, for patients who progress after chemotherapy, its effectiveness diminishes due to the emergence of multi-drug resistance (MDR after prolonged therapy. METHODOLOGY/PRINCIPAL FINDINGS: In order to overcome both the dose-limiting side effects of conventional chemotherapeutic agents and the therapeutic failure resulting from MDR, we designed and evaluated a novel drug delivery system for MDR1 siRNA delivery. Novel biocompatible, lipid-modified dextran-based polymeric nanoparticles were used as the platform for MDR1 siRNA delivery; and the efficacy of combination therapy with this system was evaluated. In this study, multi-drug resistant osteosarcoma cell lines (KHOS(R2 and U-2OS(R2 were treated with the MDR1 siRNA nanocarriers and MDR1 protein (P-gp expression, drug retention, and immunofluoresence were analyzed. Combination therapy of the MDR1 siRNA loaded nanocarriers with increasing concentrations of doxorubicin was also analyzed. We observed that MDR1 siRNA loaded dextran nanoparticles efficiently suppresses P-gp expression in the drug resistant osteosarcoma cell lines. The results also demonstrated that this approach may be capable of reversing drug resistance by increasing the amount of drug accumulation in MDR cell lines. CONCLUSIONS/SIGNIFICANCE: Lipid-modified dextran-based polymeric nanoparticles are a promising platform for siRNA delivery. Nanocarriers loaded with MDR1 siRNA are a potential treatment strategy for reversing MDR in osteosarcoma.

  5. Low ABCB1 gene expression is an early event in colorectal carcinogenesis

    Andersen, Vibeke; Vogel, Ulla Birgitte; Godiksen, Sine; Frenzel, Franz B; Sæbø, Mona; Hamfjord, Julian; Kure, Elin; Vogel, Lotte K

    2013-01-01

    risk and interactions between the ABCB1 C-rs3789243-T and C3435T polymorphisms and meat intake in relation to CRC risk (Andersen, BMC Cancer, 2009, 9, 407). ABCB1 and NFKB1 mRNA levels were assessed in intestinal tissue from 122 CRC cases, 101 adenoma cases (12 with severe dysplasia, 89 with mild......The ABCB1/MDR1 gene product ABCB1/P-glycoprotein is implicated in the development of colorectal cancer (CRC). NFKB1 encodes transcription factors regulating expression of a number of genes including ABCB1. We have previously found association between the ABCB1 C-rs3789243-T polymorphism and CRC...

  6. ABCB1 (MDR1) polymorphisms and ovarian cancer progression and survival

    Johnatty, Sharon E; Beesley, Jonathan; Gao, Bo;

    2013-01-01

    ABCB1 encodes the multi-drug efflux pump P-glycoprotein (P-gp) and has been implicated in multi-drug resistance. We comprehensively evaluated this gene and flanking regions for an association with clinical outcome in epithelial ovarian cancer (EOC).......ABCB1 encodes the multi-drug efflux pump P-glycoprotein (P-gp) and has been implicated in multi-drug resistance. We comprehensively evaluated this gene and flanking regions for an association with clinical outcome in epithelial ovarian cancer (EOC)....

  7. Rapid genotyping assays for the 4-base pair deletion of canine MDR1/ABCB1 gene and low frequency of the mutant allele in Border Collie dogs.

    Mizukami, Keijiro; Chang, Hye-Sook; Yabuki, Akira; Kawamichi, Takuji; Hossain, Mohammad A; Rahman, Mohammad M; Uddin, Mohammad M; Yamato, Osamu

    2012-01-01

    P-glycoprotein, encoded by the MDR1 or ABCB1 gene, is an integral component of the blood-brain barrier as an efflux pump for xenobiotics crucial in limiting drug uptake into the central nervous system. Dogs homozygous for a 4-base pair deletion of the canine MDR1 gene show altered expression or function of P-glycoprotein, resulting in neurotoxicosis after administration of the substrate drugs. In the present study, the usefulness of microchip electrophoresis for genotyping assays detecting this deletion mutation was evaluated. Mutagenically separated polymerase chain reaction (MS-PCR) and real-time PCR assays were newly developed and evaluated. Furthermore, a genotyping survey was carried out in a population of Border Collies dogs in Japan to determine the allele frequency in this breed. Microchip electrophoresis showed advantages in detection sensitivity and time saving over other modes of electrophoresis. The MS-PCR assay clearly discriminated all genotypes. Real-time PCR assay was most suitable for a large-scale survey due to its high throughput and rapidity. The genotyping survey demonstrated that the carrier and mutant allele frequencies were 0.49% and 0.25%, respectively, suggesting that the mutant allele frequency in Border Collies is markedly low compared to that in the susceptible dog breeds such as rough and smooth Collies. PMID:22362942

  8. Analysis of genotype and haplotype effects of ABCB1 (MDR1) polymorphisms in the risk of medically refractory epilepsy in an Indian population.

    Vahab, Saadi Abdul; Sen, Supratim; Ravindran, Nivedita; Mony, Sridevi; Mathew, Anila; Vijayan, Neetha; Nayak, Geetha; Bhaskaranand, Nalini; Banerjee, Moinak; Satyamoorthy, Kapaettu

    2009-01-01

    The transmembrane P-glycoprotein that functions as a drug-efflux transporter coded by ATP-binding cassette, subfamily B, member 1/Multidrug Resistance 1 (ABCB1/MDR1) gene is considered relevant to drug absorption and elimination, with access to the central nervous system. Effects of three ABCB1 single nucleotide polymorphisms (SNPs) in genotypic and haplotypic combination have been evaluated in a south Indian population for risk of pediatric medically refractory epilepsy. The study included age and sex matched medically refractory (N=113) cases and drug responsive epilepsy patients (N=129) as controls, belonging to the same ethnic population recruited from a tertiary referral centre, of Karnataka, Southern India. The genotype frequencies of SNPs c.1236C>T, c.2677G>T/A, and c.3435C>T were determined from genomic DNA of the cases and controls by PCR- RFLP and confirmatory DNA sequencing. 256 normal population samples of the same ethnicity were genotyped for the three loci to check for population stratification. Results indicate that there was no statistically significant difference between allele and genotype frequencies of refractory and drug responsive epilepsy patients. The predicted haplotype frequencies of the three polymorphisms did not show significant difference between cases and controls. The results confirm earlier observations on absence of association of ABCB1 polymorphisms with medically refractory epilepsy. PMID:19571437

  9. MDR1 gene expression in primary colorectal carcinomas.

    Pirker, R; Wallner, J.; Gsur, A; Götzl, M.; Zöchbauer, S; Scheithauer, W.; Depisch, D

    1993-01-01

    The expression of the MDR1 gene, a multidrug resistance gene, was prospectively determined in 113 primary colorectal carcinoma specimens and correlated with clinical data including survival durations of the patients. MDR1 RNA was detected in 65% of the carcinomas. No expression of the MDR2 gene was seen, MDR1 gene expression was independent of age and sex of the patients, size and histologic grading of the tumour, lymph node involvement and distant metastasis. Kaplan-Meier analysis revealed t...

  10. Functional expression of mouse mdr1 in Escherichia coli.

    Bibi, E; Gros, P.; Kaback, H R

    1993-01-01

    We describe functional expression of the mouse multidrug-resistance protein (P-glycoprotein; P-gp) in an Escherichia coli mutant defective in the outer membrane protease ompT. Heterologously expressed mdr1 appears as an unglycosylated species with an apparent molecular mass of 140 kDa in the membrane of the mutant. Unglycosylated mdr1 retains the ability to bind the photoactivatable drug analog [125I]iodoarylazidoprazosin and confers resistance to tetraphenylphosphonium (TPP+) and tetraphenyl...

  11. High frequency of a single nucleotide substitution (c.-6-180T>G) of the canine MDR1/ABCB1 gene associated with phenobarbital-resistant idiopathic epilepsy in Border Collie dogs.

    Mizukami, Keijiro; Yabuki, Akira; Chang, Hye-Sook; Uddin, Mohammad Mejbah; Rahman, Mohammad Mahbubur; Kushida, Kazuya; Kohyama, Moeko; Yamato, Osamu

    2013-01-01

    A single nucleotide substitution (c.-6-180T>G) associated with resistance to phenobarbital therapy has been found in the canine MDR1/ABCB1 gene in Border Collies with idiopathic epilepsy. In the present study, a PCR-restriction fragment length polymorphism assay was developed for genotyping this mutation, and a genotyping survey was carried out in a population of 472 Border Collies in Japan to determine the current allele frequency. The survey demonstrated the frequencies of the T/T wild type, T/G heterozygote, and G/G mutant homozygote to be 60.0%, 30.3%, and 9.8%, respectively, indicating that the frequency of the mutant G allele is extremely high (24.9%) in Border Collies. The results suggest that this high mutation frequency of the mutation is likely to cause a high prevalence of phenobarbital-resistant epilepsy in Border Collies. PMID:24302812

  12. High Frequency of a Single Nucleotide Substitution (c.-6-180T>G of the Canine MDR1/ABCB1 Gene Associated with Phenobarbital-Resistant Idiopathic Epilepsy in Border Collie Dogs

    Keijiro Mizukami

    2013-01-01

    Full Text Available A single nucleotide substitution (c.-6-180T>G associated with resistance to phenobarbital therapy has been found in the canine MDR1/ABCB1 gene in Border Collies with idiopathic epilepsy. In the present study, a PCR-restriction fragment length polymorphism assay was developed for genotyping this mutation, and a genotyping survey was carried out in a population of 472 Border Collies in Japan to determine the current allele frequency. The survey demonstrated the frequencies of the T/T wild type, T/G heterozygote, and G/G mutant homozygote to be 60.0%, 30.3%, and 9.8%, respectively, indicating that the frequency of the mutant G allele is extremely high (24.9% in Border Collies. The results suggest that this high mutation frequency of the mutation is likely to cause a high prevalence of phenobarbital-resistant epilepsy in Border Collies.

  13. Quantitative analysis of MDR1 (multidrug resistance) gene expression in human tumors by polymerase chain reaction

    Noonan, K.E.; Beck, C.; Holzmayer, T.A.; Chin, J.E.; Roninson, I.B. (Univ. of Illinois, Chicago (USA)); Wunder, J.S.; Andrulis, I.L. (Mount Sinai Hospital, Toronto, Ontario (Canada)); Gazdar, A.F. (National Cancer Inst., Bethesda, MD (USA)); Willman, C.L.; Griffith, B. (Univ. of New Mexico, Albuquerque (USA)); Von Hoff, D.D. (Univ. of Texas, San Antonio (USA))

    1990-09-01

    The resistance of tumor cells ot chemotheraprutic drugs is a major obstacle to successful cancer chemotherapy. In human cells, expression of the MDR1 gene, encoding a transmembrane efflux pump (P-glycoprotein), leads to decreased intracellular accumulation and resistance to a variety of lipophilic drugs (multidrug resistance; MDR). The levels of MDR in cell lines selected in bitro have been shown to correlate with the steady-state levels of MDR1 mRNA and P-glycoprotein. In cells with a severalfold increase in cellular drug resistance, MDR1 expression levels are close to the limits of detection by conventional assays. MDR1 expression has been frequently observed in human tumors after chemotherapy and in some but not all types of clinically refactory tumors untreated with chemotherapeutic drugs. The authors have devised a highly sensitive, specific, and quantitative protocol for measuring the levels of MDR1 mRNA in clincal samples, based on the polymerase chain reaction. They have used this assay to measure MDR1 gene expression in MDR cell lines and >300 normal tissues, tumor-derived cell lines, and clinical specimens of untreated tumors of the types in which MDR1 expression was rarely observed by standard assays. Low levels of MDR1 expression were found by polymerase chain reaction in most solid tumors and leukemias tested. The frequency of samples without detectable MDR1 expression varied among different types of tumors; MDR1-negative samples were ost common among tumor types known to be relatively responsive to chemotherapy.

  14. Detection of MDR1 mRNA expression with optimized gold nanoparticle beacon

    Zhou, Qiumei; Qian, Zhiyu; Gu, Yueqing

    2016-03-01

    MDR1 (multidrug resistance gene) mRNA expression is a promising biomarker for the prediction of doxorubicin resistance in clinic. However, the traditional technical process in clinic is complicated and cannot perform the real-time detection mRNA in living single cells. In this study, the expression of MDR1 mRNA was analyzed based on optimized gold nanoparticle beacon in tumor cells. Firstly, gold nanoparticle (AuNP) was modified by thiol-PEG, and the MDR1 beacon sequence was screened and optimized using a BLAST bioinformatics strategy. Then, optimized MDR1 molecular beacons were characterized by transmission electron microscope, UV-vis and fluorescence spectroscopies. The cytotoxicity of MDR1 molecular beacon on L-02, K562 and K562/Adr cells were investigated by MTT assay, suggesting that MDR1 molecular beacon was low inherent cytotoxicity. Dark field microscope was used to investigate the cellular uptake of hDAuNP beacon assisted with ultrasound. Finally, laser scanning confocal microscope images showed that there was a significant difference in MDR1 mRNA expression in K562 and K562/Adr cells, which was consistent with the results of q-PCR measurement. In summary, optimized MDR1 molecular beacon designed in this study is a reliable strategy for detection MDR1 mRNA expression in living tumor cells, and will be a promising strategy for in guiding patient treatment and management in individualized medication.

  15. Prognostic significance of MDR-1 P-glycoprotein expression in breast cancer

    Huilin Zhang; Wandong Zhang; Fengshan Li

    2008-01-01

    Objective: To investigate the expression of MDR-1 P-glycoprotein(MDR-1 Pgp) in breast cancer and analyze its correlation to the biological behavior and prognosis of the disease. Methods:The expression of MDR-1 Pgp was examined in 75 cases of breast cancer patients by using three different monoclonal antibodies0SBl, C219 and C494) with S-P immunohistochemisty. These patients were followed up for 5 years, and the correlation between MDR-1 Pgp expression, survival rate and lymph metastasis was analyzed. Results:Positive detection of MDR-1 Pgp by JSB 1, C219 and C494 in 75 cases of breast cancer was 86.7%, 48% and 85.3%, respectively.MDR-1 Pgp expression was not related to ages of patients (P>0.05). JSB 1-detected expression of MDR-1 Pgp was related to lymph node metastasis(P<0.05); while C219 and (2494 were not(P>0.05). The patients with MDR-1 Pgp expression positively detected by either two of the three antibodies, had five-year survival rate that was significantly higher than those positively detected by all the three antibodies(P<0.05). Conclusion:Three antibodies should be used simultaneously to detect MDR-1 Pgp expression in breast cancer.Positive MDR-1 Pgp expression in breast cancer detected by all the three antibodies may represent a poor prognosis; while positive MDR-1 Pgp detection by JSB1 and C494 is associated with lymph metastasis.

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

    刘杏娥; 孙晓东; 吴金民

    2004-01-01

    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.

  17. Novel understanding of ABC transporters ABCB1/MDR/P-glycoprotein, ABCC2/MRP2, and ABCG2/BCRP in colorectal pathophysiology

    Andersen, Vibeke; Svenningsen, Katrine; Knudsen, Lina Almind;

    2015-01-01

    transporter proteins, inflammatory bowel disease, ulcerative, colitis, Crohns disease, colorectal cancer, colitis, intestinal inflammation, intestinal carcinogenesis, ABCB1/P-glycoprotein (P-gp/CD243/MDR1), ABCC2/multidrug resistance protein 2 (MRP2) and ABCG2/breast cancer resistance protein (BCRP), Abcb1....../Mdr1a, abcc2/Mrp2, abcg2/Bcrp, knock-out mice, tight junction, membrane lipid function. RESULTS: Recently, human studies reported that changes in the levels of ABC transporters were early events in the adenoma-carcinoma sequence leading to CRC. A link between ABCB1, high fat diet and gut microbes in...... which may additionally affect ABC transporter function through nuclear receptors and transcriptional regulation. Another critical role of ABCB1 was suggested by the finding that ABCB1 expression identifies a subpopulation of pro-inflammatory Th17 cells which were resistant to treatment with...

  18. A new model for studying tissue-specific mdr1a gene expression in vivo by live imaging

    Gu, Long; Tsark, Walter M.; Brown, Donna A.; Blanchard, Suzette; Synold, Timothy W.; Kane, Susan E

    2009-01-01

    Multidrug resistance continues to be a major impediment to successful chemotherapy in cancer patients. One cause of multidrug resistance is enhanced expression of the mdr1 gene, but the precise factors and physiological conditions controlling mdr1 expression are not entirely known. To gain a better understanding of mdr1 transcriptional regulation, we created a unique mouse model that allows noninvasive bioimaging of mdr1 gene expression in vivo and in real time. The model uses a firefly lucif...

  19. Paclitaxel sensitivity in relation to ABCB1 expression, efflux and single nucleotide polymorphisms in ovarian cancer

    Gao, Bo; Russell, Amanda; Beesley, Jonathan; Chen, Xiao Qing; Healey, Sue; Henderson, Michelle; Wong, Mark; Emmanuel, Catherine; Johnatty, Sharon E.; ,; Bowtell, David; Gertig, Dorota; Green, Adle; Webb, Penelope; Hung, Jillian

    2014-01-01

    ABCB1 (adenosine triphosphate-binding cassette transporter B1) mediates cellular elimination of many chemotherapeutic agents including paclitaxel, which is commonly used to treat ovarian cancer. A significant association between common single nucleotide polymorphisms (SNPs) in ABCB1 and progression-free survival has been reported in patients with ovarian cancer. Variable paclitaxel clearance due to genotype specific differences in ABCB1 activity in cancer cells and/or normal tissues may under...

  20. Osimertinib (AZD9291) Attenuates the Function of Multidrug Resistance-Linked ATP-Binding Cassette Transporter ABCB1 in Vitro.

    Hsiao, Sung-Han; Lu, Yu-Jen; Li, Yan-Qing; Huang, Yang-Hui; Hsieh, Chia-Hung; Wu, Chung-Pu

    2016-06-01

    The effectiveness of cancer chemotherapy is often circumvented by multidrug resistance (MDR) caused by the overexpression of ATP-binding cassette (ABC) drug transporter ABCB1 (MDR1, P-glycoprotein). Several epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have been shown previously capable of modulating the function of ABCB1 and reversing ABCB1-mediated MDR in human cancer cells. Furthermore, some TKIs are transported by ABCB1, which results in low oral bioavailability, reduced distribution, and the development of acquired resistance to these TKIs. In this study, we investigated the interaction between ABCB1 and osimertinib, a novel selective, irreversible third-generation EGFR TKI that has recently been approved by the U.S. Food and Drug Administration. We also evaluated the potential impact of ABCB1 on the efficacy of osimertinib in cancer cells, which can present a therapeutic challenge to clinicians in the future. We revealed that although osimertinib stimulates the ATPase activity of ABCB1, overexpression of ABCB1 does not confer resistance to osimertinib. Our results suggest that it is unlikely that the overexpression of ABCB1 can be a major contributor to the development of osimertinib resistance in cancer patients. More significantly, we revealed an additional action of osimertinib that directly inhibits the function of ABCB1 without affecting the expression level of ABCB1, enhances drug-induced apoptosis, and reverses the MDR phenotype in ABCB1-overexpressing cancer cells. Considering that osimertinib is a clinically approved third-generation EGFR TKI, our findings suggest that a combination therapy with osimertinib and conventional anticancer drugs may be beneficial to patients with MDR tumors. PMID:27169328

  1. Quantitative analysis of MDR1 (multidrug resistance) gene expression in human tumors by polymerase chain reaction.

    Noonan, K E; Beck, C.; Holzmayer, T A; Chin, J E; Wunder, J.S.; Andrulis, I.L.; Gazdar, A F; Willman, C.L.; Griffith, B.; Von Hoff, D. D.

    1990-01-01

    The resistance of tumor cells to chemotherapeutic drugs is a major obstacle to successful cancer chemotherapy. In human cells, expression of the MDR1 gene, encoding a transmembrane efflux pump (P-glycoprotein), leads to decreased intracellular accumulation and resistance to a variety of lipophilic drugs (multidrug resistance; MDR). The levels of MDR in cell lines selected in vitro have been shown to correlate with the steady-state levels of MDR1 mRNA and P-glycoprotein. In cells with a severa...

  2. Significant activity of ecdysteroids on the resistance to doxorubicin in mammalian cancer cells expressing the human ABCB1 transporter.

    Martins, Ana; Tóth, Noémi; Ványolós, Attila; Béni, Zoltán; Zupkó, István; Molnár, József; Báthori, Mária; Hunyadi, Attila

    2012-06-14

    Multidrug resistance (MDR) is a major cause of failure of cancer chemotherapy. Fifty-eight ecdysteroids, herbal analogues of the insect molting hormone and their semisynthetic derivatives, were tested for their activity against L5178 mouse T-cell lymphoma cells (non-MDR) and their subcell line transfected with pHa MDR1/A retrovirus overexpressing the human ABCB1 efflux pump (MDR cell line). The compounds showed very low antiproliferative activities but modulated the efflux of rhodamine 123 mediated by the ABCB1 transporter. Roughly depending on the polarity, mild to strong synergism or antagonism was observed by combining ecdysteroids with doxorubicin, and specific structure-activity relationships were also found. Our results show the effect of ecdysteroids on MDR cancer cells for the first time. Less polar derivatives may serve as valuable leads toward a potent and safe resistance modulator. Biological significance of the resistance-increasing activity of the most abundant phytoecdysteroids including 20-hydroxyecdysone is yet to be clarified. PMID:22578055

  3. OCT-1, ABCB1, and ABCG2 Expression in Imatinib-Resistant Chronic Myeloid Leukemia Treated with Dasatinib or Nilotinib

    Kim, Yeo-Kyeoung; Lee, Seung-Shin; Jeong, Sung-Hoon; Ahn, Jae-Sook; Yang, Deok-Hwan; Lee, Je-Jung; Shin, Myung-Geun; Kim, Hyeoung-Joon

    2014-01-01

    This study explored drug transporter expression levels and their impact on clinical response to imatinib and second-generation tyrosine kinase inhibitors (TKIs) in imatinib- resistant chronic myeloid leukemia (CML). Imatinib-resistant chronic phase CML patients treated with dasatinib (n=10) and nilotinib (n=12) were enrolled. The mRNA expression of the OCT-1, ABCG2, and ABCB1 genes was quantified by using paired bone marrow samples obtained before administering imatinib and at the point of de...

  4. ESTABLISHMENT OF CRITERIA FOR MEASURING MDR-1 GENE EXPRESSION LEVEL IN BREAST CANCER BY RT-PCR

    Liu Xiaoqing; Song Santai; Shi Chenghua; Xu Jianming; Tang Zhongming; Jiang Zefei

    1998-01-01

    Objective: To formulate criteria of multidrug resistance (mdr-1) gene expression for predicting chemotherapy response and prognosis. Methods: Using reverse transcription-polymerase chain reaction (RTPCR) assay, the expression of mdr-1 gene in 82 breast cancer samples were detected. Results: The data were treated by statistic analysis system (SAS)-singlevariate analysis. It showed that the level of mdr-1 gene expression clearly deviated from normal to right distribution (P<0.0001), and thus might be divided by quantiles P50(mdr-1/β 2-MG=0.2) and P75 (mdr-1/β 2-MG=0.6), which were taken as the preliminary criteria for analyzing 56 patients' chemosensitivity to ADM、 VDS and VCR in vitro and 32 relapsed metastatic patients' chemotherapy response in vivo, seperately. When mdr-1/β 2-MG<0.2, the ratios of resistance gradually escalated, but there were about 30%~50% of the cases who showed sensitive to the drugs in vitro and effective to chemotherapy in vivo. When mdr-1/β 2-MG≥0.6, the most of patients showed drug resistance both in vitro and in vivo. Conclusion:According to the above-mentioned results, criteria of evaluating mdr-1 gene expression level was formulated:the mdr-1/β 2-MG<0.2 (P50) was considered as negative expression, the ratio≥0.2~<0.6 (P75) was weakly positive expression, ≥0.6 was strongly positive expression. This indicated that different levels of mdr-1 gene expression may reflect objectively drug resistance in vitro and chemotherapy response in vivo.

  5. Experimental coccidiosis influences the expression of the ABCB1 gene, a physiological important functional marker of intestinal integrity in chickens.

    Haritova, Aneliya; Koinarski, Vencislav; Stanilova, Spaska

    2013-01-01

    Efflux transporters belonging to the family of ABC transporters have an important functional role in the maintenance of the intestinal barrier. As efflux transporters they prevent the absorption of toxic substances from feed, while at the same time facilitating the excretion of metabolic waste products as well as drugs from the circulation into the intestinal lumen. As Eimeria tenella infection significantly affects the integrity of caecum, the effects of experimental E. tenella infection on the levels of expression of ABCB1 mRNAs in the intestines and livers of broilers were evaluated. ABCB1 mRNA expression was quantified by qRT-PCR. Its expression levels were significantly down-regulated in the caecum of infected animals. The levels of ABCB1 mRNA were not changed in the duodenum and the liver. After treatment of the animals with sulfapyrazine for three days, not only a significant improvement of the clinical appearance but also a normalization of the P-gp expression was noticed. Although the current study cannot distinguish between the direct effect of the drug on the host and the drug action on the parasite, these results suggest that the treatment of coccidiosis with sulfachlorpyrazine also restored the expression of the investigated efflux transporter in the caecum. This is of clinical significance as P-glycoproteins contribute to the integrity of intestines and their function as important biological barriers, protecting poultry from pathogens and toxic compounds in animal feeds. PMID:23758033

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

    GAN Hui-zhu; ZHENG De-ming; ZHANG Gui-zhen; ZHAO Ji-sheng; ZHANG Feng-chun; BU Li-sha; YANG Shao-juan; PIAO Song-lan; DU Zhen-wu; GAO Shen

    2005-01-01

    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

  7. Validation of a P-Glycoprotein (P-gp Humanized Mouse Model by Integrating Selective Absolute Quantification of Human MDR1, Mouse Mdr1a and Mdr1b Protein Expressions with In Vivo Functional Analysis for Blood-Brain Barrier Transport.

    Muhammad Waqas Sadiq

    Full Text Available It is essential to establish a useful validation method for newly generated humanized mouse models. The novel approach of combining our established species-specific protein quantification method combined with in vivo functional studies is evaluated to validate a humanized mouse model of P-gp/MDR1 efflux transporter. The P-gp substrates digoxin, verapamil and docetaxel were administered to male FVB Mdr1a/1b(+/+ (FVB WT, FVB Mdr1a/1b(-/- (Mdr1a/1b(-/-, C57BL/6 Mdr1a/1b(+/+ (C57BL/6 WT and humanized C57BL (hMDR1 mice. Brain-to-plasma total concentration ratios (Kp were measured. Quantitative targeted absolute proteomic (QTAP analysis was used to selectively quantify the protein expression levels of hMDR1, Mdr1a and Mdr1b in the isolated brain capillaries. The protein expressions of other transporters, receptors and claudin-5 were also quantified. The Kp for digoxin, verapamil, and docetaxel were 20, 30 and 4 times higher in the Mdr1a/1b(-/- mice than in the FVB WT controls, as expected. The Kp for digoxin, verapamil and docetaxel were 2, 16 and 2-times higher in the hMDR1 compared to the C57BL/6 WT mice. The hMDR1 mice had 63- and 9.1-fold lower expressions of the hMDR1 and Mdr1a proteins than the corresponding expression of Mdr1a in C57BL/6 WT mice, respectively. The protein expression levels of other molecules were almost consistent between C57BL/6 WT and hMDR1 mice. The P-gp function at the BBB in the hMDR1 mice was smaller than that in WT mice due to lower protein expression levels of hMDR1 and Mdr1a. The combination of QTAP and in vivo functional analyses was successfully applied to validate the humanized animal model and evaluates its suitability for further studies.

  8. Expression of GST-pi and MDR1 genes in operative specimens of ovarian cancer%卵巢癌组织中GST-π和MDR1基因的表达及其意义

    卞丽红; 黄长江; 陈高明; 孙丽娅; 李春海; 傅才英; 李亚里

    2001-01-01

    Objectives:To study the expression of GST-pi and MDR1 genes in operative specimens of ovarian cancer,and to analyze the possible clinical role of GST-pi and MDR1. Methods:Eighteen frozen specimens of ovarian carcinoma and ten specimens of normal ovarian tissues from patients were examined for the expression of GST-pi and MDR1 genes by means of RT-PCR, and quantitative analysis was performed using β-actin as internal contrast.Results: Positive expression rate of GST-pi and MDR1 in ovarian carcinoma were 61.1% and 33.3%,respectively,and in contrast, 20% and 10% in normal ovarian tissues respectively. The level of GST-pi gene expression in ovarian carcinoma was obviously higher than that in normal ovarian tissue (P<0.05)and MDR1 gene also had high level expression in ovarian carcinoma, but had no statistical significantance. Four patients with ovarian carcinoma had GST-pi and MDR1 coexpression. Expression levels of GST-pi mRNA were lower than that of protein. Conclusions: (1) GST-pi and MDR1 had higher level expression in ovarian carcinoma than in normal ovarian tissues. (2) GST-pi and MDR1 may have same regulating factors but different mechanisms of action. (3)Processing after transcription and/or regulation of translation level may exist in GST-pi expression.%目的:观察两种耐药基因谷胱甘肽S-转移酶-pi(GST-π)和MDR1在卵巢癌组织中mRNA水平的表达情况,探讨其表达的意义及应用价值.方法:采用逆转录PCR方法检测了18例卵巢癌和10例正常卵巢组织中GST-π和MDR1的表达,应用β-肌动蛋白作为内对照进行定量分析比较.结果:GST-π和MDR1在正常卵巢组织中表达的阳性率分别是20%和10%,在卵巢癌中的阳性表达率分别是61.1%和33.3%.GST-π在癌组织表达高于正常组织,两者比较P<0.05;而MDR1在癌组织表达虽高于正常组织但无统计学意义;在癌组织中有4例同时出现了GST-π和MDR1的共表达;GST-π mRNA水平的表达低于蛋白水平的表达.结论:(1

  9. Tissue Distribution, Gender-Divergent Expression, Ontogeny, and Chemical Induction of Multidrug Resistance Transporter Genes (Mdr1a, Mdr1b, Mdr2) in Mice

    Cui, Yue Julia; Cheng, Xingguo; Weaver, Yi Miao; Klaassen, Curtis D.

    2008-01-01

    Multidrug resistance (Mdr) transporters are ATP-binding cassette transporters that efflux amphipathic cations from cells and protect tissues from xenobiotics. Unfortunately, Mdr transporters also efflux anticancer drugs from some tumor cells, resulting in multidrug resistance. There are two groups of Mdrs in mice: group I includes Mdr1a and Mdr1b that transport xenobiotics, whereas group II is Mdr2, a flipase that facilitates phospholipid excretion into bile. Little is...

  10. Comparison of mdr1, ERCC2,and MGMT Expression in Human Glioma%人脑胶质瘤耐药基因mdr1、ERCC2、MGMT的表达及相关性分析

    王爱东; 黄强; 罗良生; 陈忠平

    2001-01-01

    目的:探讨人脑胶质瘤组织中三种耐药基因mdr1、ERCC2和MGMTmRNA表达之间的相关性。方法:采用双管RT-PCR方法检测14例正常脑组织和56例人脑胶质瘤组织中mdr1、ERCC2和MGMTmRNA水平,并分析其相关性。结果:正常脑组织中mdr1、ERCC2和MGMT的表达量分别为(0.75±0.36),(1.43±0.92)和(2.48±1.83),mdr1和ERCC2、ERCC2和MGMT之间具相关性(P<0.01和P<0.001);胶质瘤组织中三种基因表达量分别为(0.53±0.42),(1.75±1.16)和(2.88±1.92),ERCC2和MGMT之间具极显著相关性(P<0.001)。结论:ERCC2和MGMT基因的表达之间可能具有内在的联系,共同参与细胞对DNA损伤的修复,并形成耐药;而mdr1与上述两者之间不具有这种关系。%Objective: This study was designed to evaluate the relationship among mdr1, ERCC2,and MGMT expression in human glioma. Methods: RT-PCR method was used to determine the mRNA levels of mdr1, ERCC2, and MGMT gene in 14 normal brain tissues and 56 human gliomas,and the relationship between these gene expression was analyzed. Results: In normal brain tissues, there was significant concordance between ERCC2 expression and mdr1 (P<0.01) expression or MGMT (P<0.001) expression. A significant correlation was also found between the expression of ERCC2 and MGMT in glioma specimens (P<0.001). Conclusion: The results suggest that there may be intrinsic relationship between ERCC2 and MGMT expression in human gliomas which affect DNA repair resulting in drug resistance.

  11. P-Glycoprotein/MDR1 Regulates Pokemon Gene Transcription Through p53 Expression in Human Breast Cancer Cells

    Wei Xu; Yuyang Jiang; Xuyu Zu; Shengnan He; Zhenhua Xie; Feng Liu

    2010-01-01

    P-glycoprotein (Pgp), encoded by the multidrug resistance 1 (MDR1) gene, is an efflux transporter and plays an important role in pharmacokinetics. In this study, we demonstrated that the pokemon promoter activity, the pokemon mRNA and protein expression can be significantly inhibited by Pgp. Chromatin immunoprecipitation assay showed that Pgp can bind the pokemon prompter to repress pokemon transcription activity. Furthermore, Pgp regulated pokemon transcription activity through expression of...

  12. MDR1 P-glycoprotein is expressed by endothelial cells of newly formed capillaries in human gliomas but is not expressed in the neovasculature of other primary tumors.

    Tóth, K.; Vaughan, M. M.; Peress, N. S.; Slocum, H. K.; Rustum, Y M

    1996-01-01

    The expression of human MDR1 P-glycoprotein (Pgp) in the capillary endothelial cells of the central nervous system has been demonstrated. The brain capillary endothelial cells maintain the structure and function of the blood-brain barrier. Recently, the human MDR1 Pgp (and its mouse homologue MDR1a Pgp) has been shown to function as an important part of this barrier, pumping out xenobiotics from endothelial cells into the lumen of capillaries resulting in the protection of the brain parenchym...

  13. Preferential cytotoxicity of bortezomib toward highly malignant human liposarcoma cells via suppression of MDR1 expression and function

    Hu, Yamei; Wang, Lingxian; Wang, Lu; Wu, Xuefeng; Wu, Xudong [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093 (China); Gu, Yanhong; Shu, Yongqian [Department of Clinical Oncology, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029 (China); Sun, Yang [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093 (China); Shen, Yan, E-mail: shenyan@nju.edu.cn [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093 (China); Xu, Qiang, E-mail: molpharm@163.com [State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing 210093 (China)

    2015-02-15

    Liposarcoma is the most common soft tissue sarcoma with a high risk of relapse. Few therapeutic options are available for the aggressive local or metastatic disease. Here, we report that the clinically used proteasome inhibitor bortezomib exhibits significantly stronger cytotoxicity toward highly malignant human liposarcoma SW872-S cells compared with its parental SW872 cells, which is accompanied by enhanced activation of apoptotic signaling both in vitro and in vivo. Treatment of cells with Jun-N-terminal kinase (JNK) inhibitor SP60015 or the translation inhibitor cycloheximide ameliorated this enhanced apoptosis. Bortezomib inhibited MDR1 expression and function more effectively in SW872-S cells than in SW872 cells, indicating that the increased cytotoxicity relies on the degree of proteasome inhibition. Furthermore, the pharmacological or genetic inhibition of sarco/endoplasmic reticulum calcium-ATPase (SERCA) 2, which is highly expressed in SW872-S cells, resulted in partial reversal of cell growth inhibition and increase of MDR1 expression in bortezomib-treated SW872-S cells. These results show that bortezomib exhibits preferential cytotoxicity toward SW872-S cells possibly via highly expressed SERCA2-associated MDR1 suppression and suggest that bortezomib may serve as a potent agent for treating advanced liposarcoma. - Highlights: • We compare the cytotoxicity of different drugs between SW872-S and SW872 cells. • Highly malignant liposarcoma cells SW872-S show hypersensitivity to bortezomib. • Apoptotic signaling is robustly enhanced in bortezomib-treated SW872-S cells. • Bortezomib has strong suppression on MDR1 expression and function in SW872-S cells. • Inhibition of SERCA2 protects SW872-S cells from bortezomib.

  14. Effects of Momordica charantia Extract on the Expression of MDR 1 Gene in Human Lung Cancer Cells

    T Yuan

    2014-10-01

    Full Text Available Objectives: Multi-drug resistance (MDR is a major hurdle in treatment of cancer, contributing to the failure of chemotherapy. Drug resistance is found to be linked to the overexpression of ATP-binding cassette (ABC drug transporter proteins that include P-glycoprotein (P-gp, causing a reduction in drug accretion inside the cancer cells. In the present study, the effect of the extracts from the fruit peel and pulp of Momordica charantia (MCFPE fruit in modulating the function of P-gp in human small-cell lung cancer (SCLC cell lines was assessed. Methods: The effects of MCFPE were tested on drug-sensitive (H69 and multi-drug resistant (H69/LX4 human SCLC cells. The cell survival percentage was assessed by MTT cytotoxicity assay. The percentage of drug accumulation and drug efflux were assessed by using [3H]-paclitaxel. The expression of MDR1 gene was analysed by reverse transcription polymerase chain reaction (RT-PCR, and P-gp by western blot analysis. Results: The extract was able to induce death of cancer cells as measured by cell survival percentage as well as improve drug accumulation, as evidenced by intracellular paclitaxel retention. Prior exposure of cells to MCFPE reversed resistance to paclitaxel. Treatment with MCFPE was found to have a significant impact on MDR 1 gene expression in H69/LX4 cell line by decreasing its expression. The extract had no influence on expression of MDR 1 gene in the drug-sensitive SCLC cell lines. Western blot analysis of P-gp protein in H69 and H69/LX4 cells revealed that the treatment with the extract modulates the expression of MDR 1 in H69/LX4 and had negligible effect on H69 cells. Conclusion: The results indicate that MCFPE was able to effectively reverse multi-drug resistance and improve cancer chemotherapy.

  15. Sinomenine sensitizes multidrug-resistant colon cancer cells (Caco-2 to doxorubicin by downregulation of MDR-1 expression.

    Zhen Liu

    Full Text Available Chemoresistance in multidrug-resistant (MDR cells over expressing P-glycoprotein (P-gp encoded by the MDR1 gene, is a major obstacle to successful chemotherapy for colorectal cancer. Previous studies have indicated that sinomenine can enhance the absorption of various P-gp substrates. In the present study, we investigated the effect of sinomenine on the chemoresistance in colon cancer cells and explored the underlying mechanism. We developed multidrug-resistant Caco-2 (MDR-Caco-2 cells by exposure of Caco-2 cells to increasing concentrations of doxorubicin. We identified overexpression of COX-2 and MDR-1 genes as well as activation of the NF-κB signal pathway in MDR-Caco-2 cells. Importantly, we found that sinomenine enhances the sensitivity of MDR-Caco-2 cells towards doxorubicin by downregulating MDR-1 and COX-2 expression through inhibition of the NF-κB signaling pathway. These findings provide a new potential strategy for the reversal of P-gp-mediated anticancer drug resistance.

  16. Prognostic Significance of Multidrug Resistance Gene 1 (MDR1), Multidrug Resistance-related Protein (MRP) and Lung Resistance Protein (LRP) mRNA Expression in Acute Leukemia

    Huh, Hee Jin; Park, Chan-Jeoung; Jang, Seongsoo; Seo, Eul-Ju; Chi, Hyun-Sook; Lee, Je-Hwan; Lee, Kyoo-Hyung; Seo, Jong Jin; Moon, Hyung Nam; Ghim, Thad

    2006-01-01

    The prognostic significance of multidrug resistance (MDR) gene expression is controversial. We investigated whether multidrug resistance gene 1 (MDR1), multidrug resistance-related protein (MRP) and lung resistance protein (LRP) mRNA expression are associated with outcomes in acute leukemia patients. At diagnosis we examined MDR1, MRP and LRP mRNA expression in bone marrow samples from 71 acute leukemia patients (39 myeloid, 32 lymphoblastic) using nested RT-PCR. The expression of each of the...

  17. Involvement of CtBP1 in the Transcriptional Activation of the MDR1 Gene in Human Multidrug Resistant Cancer Cells

    Jin, Wei; Scotto, Kathleen W.; Hait, William N.; Yang, Jin-Ming

    2007-01-01

    Drug resistance caused by overexpression of P-glycoprotein (P-gp), the MDR1 (ABCB1) gene product, limits the therapeutic outcome. Expression of MDR1 can be induced by divergent stimuli, and involves a number of transcriptional factors. We found that the expression of CtBP1 (C-terminal-binding protein 1), a transcriptional co-regulator, was increased (~4 – fold) in human multidrug resistant (MDR) cancer cell lines, NCI/ADR-RES and A2780/DX, as compared to their sensitive counterparts. Silencin...

  18. Wallichinine reverses ABCB1-mediated cancer multidrug resistance.

    Lv, Min; Qiu, Jian-Ge; Zhang, Wen-Ji; Jiang, Qi-Wei; Qin, Wu-Ming; Yang, Yang; Zheng, Di-Wei; Chen, Yao; Huang, Jia-Rong; Wang, Kun; Wei, Meng-Ning; Cheng, Ke-Jun; Shi, Zhi

    2016-01-01

    Overexpression of ABCB1 in cancer cells is one of the main reasons of cancer multidrug resistance (MDR). Wallichinine is a compound isolated from piper wallichii and works as an antagonist of platelet activiating factor receptor to inhibit the gathering of blood platelet. In this study, we investigate the effect of wallichinine on cancer MDR mediated by ABCB1 transporter. Wallichinine significantly potentiates the effects of two ABCB1 substrates vincristine and doxorubicin on inhibition of growth, arrest of cell cycle and induction of apoptosis in ABCB1 overexpressing cancer cells. Furthermore, wallichinine do not alter the sensitivity of non-ABCB1 substrate cisplatin. Mechanistically, wallichinine blocks the drug-efflux activity of ABCB1 to increase the intracellular accumulation of rhodamine 123 and doxorubicin and stimulates the ATPase of ABCB1 without alteration of the expression of ABCB1. The predicted binding mode shows the hydrophobic interactions of wallichinine within the large drug binding cavity of ABCB1. At all, our study of the interaction of wallichinine with ABCB1 presented herein provides valuable clues for the development of novel MDR reversal reagents from natural products. PMID:27508017

  19. Decreased expression of the amplified mdr1 gene in revertants of multidrug-resistant human myelogenous leukemia K562 occurs without loss of amplified DNA.

    Sugimoto, Y.; Roninson, I B; Tsuruo, T.

    1987-01-01

    Amplification and increased expression of the mdr1 gene associated with multidrug resistance in human tumors were found in multidrug-resistant sublines of human myelogenous leukemia K562 selected with vincristine (K562/VCR) or adriamycin (K562/ADM). In two revertant cell lines of K562/ADM, amplification of the mdr1 gene was maintained at the same level as in K562/ADM, but expression of the 4.5-kilobase mdr1 mRNA was greatly decreased, indicating that amplified genes may be inactivated at the ...

  20. MDR1 Gene Polymorphisms and Clinical Relevance%MDR1基因多态性及其临床相关性研究进展

    李艳红; 王永华; 李燕; 杨凌

    2006-01-01

    体内外研究证明,人体中P-gp在药物的吸收、分布、代谢和排泄(ADME)过程中发挥了非常重要的作用.多药耐药基因MDR1(ABCB1)是P-gp的编码基因.药物基因组学和遗传药理学研究发现在不同个体中MDR1基因多态性与P-gp表达和功能的改变密切相关,而且这些多态位点存在基因型分布和等位基因频率的种族差异性.近几年,已陆续发现在MDR1基因中有50处单核苷酸多态性(SNPs)和3处插入与缺失多态性.随后,大量文献报道某些位点的SNPs如C3435T会使个体患病的易感性增加.因此人们相信,深入研究MDR1基因多态性与P-gp的生理和生化方面的相关性将对个体医疗有着非常深远的意义.文章总结了国外最新的研究进展并结合本实验室的工作着重讨论了4个方面:1)P-gp对药代动力学性质的影响;2)MDR1基因多态性及其对遗传药理学性质的影响;3)MDR1C3435T的单核苷酸多态性与P-gp表达和功能之间的相关性;4)MDR1基因多态性与人类某些疾病之间的相关性.%In vivo and in vitro studies have demonstrated that P-glycoprotein (P-gp) plays a very significant role in the ADME processes (absorption, distribution, metabolism, excretion) and drug-drug interaction (DDI) of drugs in humans. P-gp is the product of multidrug resistance gene (MDR1/ABCB1). Pharmacogenomics and pharmacogenetics studies have revealed that genetic polymorphisms of MDR1 are associated with alteration in P-gp expression and function in different ethnicities and subjects. By now, 50single nucleotide polymorphisms (SNPs) and 3 insertion/deletion polymorphisms have been found in the MDR1 gene. Some of them, such as C3435T, have been identified to be a risk factor for numerous diseases. It is believed that further understanding of the physiology and biochemistry of P-gp with respect to its genetic variations may be important for individualized pharmacotherapy.Therefore, based on the latest public information

  1. Sestamibi is a substrate for MDR1 and MDR2 P-glycoprotein genes

    Joseph, Brigid; Malhi, Harmeet; Gupta, Sanjeev [Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Ullmann 625, 1300 Morris Park Avenue, NY 10461, Bronx (United States); Bhargava, Kuldeep K.; Palestro, Christopher J. [Division of Nuclear Medicine, Long Island Jewish Medical Center, New York (United States); Schilsky, Michael L. [Division of Liver Diseases, Mount Sinai School of Medicine, New York (United States); Jain, Diwakar [Division of Nuclear Cardiology, MCP-Hahnemann University School of Medicine, Philadephia (United States)

    2003-07-01

    Technetium-99m sestamibi has attracted interest for assessment of the function of P-glycoproteins, which are well expressed in the liver and have roles in biliary transport and the removal of chemotherapeutic drugs. To further examine the cross-reactivity of {sup 99m}Tc-sestamibi for P-glycoprotein family members, we conducted studies in animals. Hepatobiliary secretion of {sup 99m}Tc-sestamibi was determined in normal FVB/N mice, mutant mice with specific P-glycoprotein deficiencies in the FVB/N background, normal Long-Evans Agouti (LEA) rats, and Long-Evans Cinnamon (LEC) rats with abnormal copper transport and liver disease but intact P-glycoprotein expression. After intrasplenic injection, {sup 99m}Tc-sestamibi was rapidly incorporated in the mouse and rat liver, with maximal accumulation after 102{+-}31 and 109{+-}16 s, respectively (P=NS). In normal mice and rats, 55%{+-}11% and 55%{+-}6%, respectively, of the maximal sestamibi activity was retained in the liver after 1 h (P=NS). In double knockout mice lacking both mdr1a and mdr1b homologs of the human MDR1 (ABCB1) gene, 88%{+-}11% of maximal sestamibi activity was retained in the liver after 1 h (P<0.001). In knockout mice deficient in either mdr1a gene or mdr2 (ABCB4) gene, biliary sestamibi excretion was also impaired, although this impairment was relatively less pronounced in ABCB4-deficient mice than in double knockout mice lacking both ABCB1 gene homologs (P<0.03). Hepatobiliary sestamibi excretion in LEC rats was not different from that in control normal rats, despite the presence of significant liver disease in the former. Hepatobiliary sestamibi excretion requires P-glycoproteins and is unperturbed in chronic liver disease. Sestamibi appears to be a substrate for both ABCB1 and ABCB4 genes, although the former utilizes it far more efficiently. Assessment of P-glycoprotein activity with sestamibi should consider how regulation of ABCB1 and related family members might modulate sestamibi incorporation

  2. The Transcription Factor Mrr1p Controls Expression of the MDR1 Efflux Pump and Mediates Multidrug Resistance in Candida albicans

    Joachim Morschhäuser; Katherine S. Barker; Liu, Teresa T.; Julia BlaB-Warmuth; Ramin Homayouni; P David Rogers

    2007-01-01

    Constitutive overexpression of the MDR1 (multidrug resistance) gene, which encodes a multidrug efflux pump of the major facilitator superfamily, is a frequent cause of resistance to fluconazole and other toxic compounds in clinical Candida albicans strains, but the mechanism of MDR1 upregulation has not been resolved. By genome-wide gene expression analysis we have identified a zinc cluster transcription factor, designated as MRR1 (multidrug resistance regulator), that was coordinately upregu...

  3. Epigenetic mechanisms involved in differential MDR1 mRNA expression between gastric and colon cancer cell lines and rationales for clinical chemotherapy

    Kim Kyung-Jong

    2008-08-01

    Full Text Available Abstract Background The membrane transporters such as P-glycoprotein (Pgp, the MDR1 gene product, are one of causes of treatment failure in cancer patients. In this study, the epigenetic mechanisms involved in differential MDR1 mRNA expression were compared between 10 gastric and 9 colon cancer cell lines. Methods The MDR1 mRNA levels were determined using PCR and real-time PCR assays after reverse transcription. Cytotoxicity was performed using the MTT assay. Methylation status was explored by quantification PCR-based methylation and bisulfite DNA sequencing analyses. Results The MDR1 mRNA levels obtained by 35 cycles of RT-PCR in gastric cancer cells were just comparable to those obtained by 22 cycles of RT-PCR in colon cancer cells. Real-time RT-PCR analysis revealed that MDR1 mRNA was not detected in the 10 gastric cancer cell lines but variable MDR1 mRNA levels in 7 of 9 colon cancer cell lines except the SNU-C5 and HT-29 cells. MTT assay showed that Pgp inhibitors such as cyclosporine A, verapamil and PSC833 sensitized Colo320HSR (colon, highest MDR1 expression but not SNU-668 (gastric, highest and SNU-C5 (gastric, no expression to paclitaxel. Quantification PCR-based methylation analysis revealed that 90% of gastric cancer cells, and 33% of colon cancer cells were methylated, which were completely matched with the results obtained by bisulfite DNA sequencing analysis. 5-aza-2'-deoxcytidine (5AC, a DNA methyltransferase inhibitor increased the MDR1 mRNA levels in 60% of gastric cells, and in 11% of colon cancer cells. Trichostatin A (TSA, histone deacetylase inhibitor increased the MDR1 mRNA levels in 70% of gastric cancer cells and 55% of colon cancer cells. The combined treatment of 5AC with TSA increased the MDR1 mRNA levels additively in 20% of gastric cancer cells, but synergistically in 40% of gastric and 11% of colon cancer cells. Conclusion These results indicate that the MDR1 mRNA levels in gastric cancer cells are significantly

  4. P-Glycoprotein/MDR1 regulates pokemon gene transcription through p53 expression in human breast cancer cells.

    He, Shengnan; Liu, Feng; Xie, Zhenhua; Zu, Xuyu; Xu, Wei; Jiang, Yuyang

    2010-01-01

    P-glycoprotein (Pgp), encoded by the multidrug resistance 1 (MDR1) gene, is an efflux transporter and plays an important role in pharmacokinetics. In this study, we demonstrated that the pokemon promoter activity, the pokemon mRNA and protein expression can be significantly inhibited by Pgp. Chromatin immunoprecipitation assay showed that Pgp can bind the pokemon prompter to repress pokemon transcription activity. Furthermore, Pgp regulated pokemon transcription activity through expression of p53 as seen by use of p53 siRNA transfected MCF-7 cells or p53 mutated MDA-MB-231 cells. Moreover, p53 was detected to bind with Pgp in vivo using immunoprecipitation assay. Taken together, we conclude that Pgp can regulate the expression of pokemon through the presence of p53, suggesting that Pgp is a potent regulator and may offer an effective novel target for cancer therapy. PMID:20957096

  5. P-Glycoprotein/MDR1 Regulates Pokemon Gene Transcription Through p53 Expression in Human Breast Cancer Cells

    Wei Xu

    2010-08-01

    Full Text Available P-glycoprotein (Pgp, encoded by the multidrug resistance 1 (MDR1 gene, is an efflux transporter and plays an important role in pharmacokinetics. In this study, we demonstrated that the pokemon promoter activity, the pokemon mRNA and protein expression can be significantly inhibited by Pgp. Chromatin immunoprecipitation assay showed that Pgp can bind the pokemon prompter to repress pokemon transcription activity. Furthermore, Pgp regulated pokemon transcription activity through expression of p53 as seen by use of p53 siRNA transfected MCF-7 cells or p53 mutated MDA-MB-231 cells. Moreover, p53 was detected to bind with Pgp in vivo using immunoprecipitation assay. Taken together, we conclude that Pgp can regulate the expression of pokemon through the presence of p53, suggesting that Pgp is a potent regulator and may offer an effective novel target for cancer therapy.

  6. ABCB1 gene polymorphisms is not associated with drug-resistant epilepsy in Romanian children

    Butila Anamaria Todoran

    2015-12-01

    Full Text Available Background: P-glycoprotein (P-gp, a drug efflux transporter, encoded by the gene MDR1 ABCB1 multidrug resistant, reduces the penetration through the brain by the AEDs. Overexpression of Pgp in blood-brain barrier in epileptic patients play an important rol in pharmacoresistance. The aim of this study was to evaluate a possible association between C1236T and G2677T ABCB1 gene polymorphisms and drug-resistant epilepsy in Romanian children.

  7. Using PCR to Compare the Expression of CDR1, CDR2, and MDR1 in Candida Albicans Isolates Resistant and Susceptible to Fluconazole

    Nahid Ariana (MSc

    2015-10-01

    Full Text Available Background and objectives: More Candida albicans strains are reported resistant to fluconazole in patients with AIDS, cancer and organ recipients. Fluconazole resistance can be attributed to changes in pathways of sterol biosynthesis, mutation in or overexpression of ERG11 and the expression of CDR1, CDR2, and MDR1. This study aimed to compare the expression of CDR1, CDR2, and MDR1 in C. albicans resistant and susceptible to fluconazole. Methods: MIC testing for fluconazole was performed on C. albicans isolates isolated from patients with oral and vaginal candidiasis to determine resistant and susceptible strains. Then real time PCR was performed on the resistant and susceptible isolates and the expression of CDR1, CDR2, and MDR1 was compared in C. albicans. Results: Of 46 Candida albicans isolates, 20 susceptible isolates, 12 semi-susceptible isolates and 14 resistant isolates were identified by MIC. After real time PCR was performed, Candida albicans isolates susceptible to fluconazole showed moderate expression of CDR1, CDR2, and MDR1 genes, while resistant isolates showed slight or no expression. Conclusion: Increased expression of CDR1, CDR2, and MDR1 had less and insignificant role in resistance to fluconazole. Keywords: Candida Albicans, Gene Expression, Real time PCR method

  8. Opioid-induced respiratory depression: ABCB1 transporter pharmacogenetics.

    Sadhasivam, S; Chidambaran, V; Zhang, X; Meller, J; Esslinger, H; Zhang, K; Martin, L J; McAuliffe, J

    2015-04-01

    Opioid-related respiratory depression (RD) is a serious clinical problem as it causes multiple deaths and anoxic brain injuries. Morphine is subject to efflux via P-glycoprotein transporter encoded by ABCB1, also known as MDR1. ABCB1 polymorphisms may affect blood-brain barrier transport of morphine and therefore individual response to its central analgesic and adverse effects. This study aimed to determine specific associations between common ABCB1 genetic variants and clinically important outcomes including RD and RD resulting in prolonged stay in hospital with intravenous morphine in a homogenous pediatric surgical pain population of 263 children undergoing tonsillectomy. Children with GG and GA genotypes of ABCB1 polymorphism rs9282564 had higher risks of RD resulting in prolonged hospital stays; adding one copy of the minor allele (G) increased the odds of prolonged hospital stay due to postoperative RD by 4.7-fold (95% confidence interval: 2.1-10.8, P=0.0002). PMID:25311385

  9. Expression of a full-length cDNA for the human MDR1 gene confers resistance to colchicine, doxorubicin, and vinblastine

    Intrinsic and acquired multidrug resistance (MDR) is an important problem in cancer therapy. MDR in human KB carcinoma cells selected for resistance to colchicine, vinblastine, or doxorubicin (former generic name adriamycin) is associated with overexpression of the MDR1 gene, which encodes P-glycoprotein. The authors previously have isolated an overlapping set of cDNA clones for the human MDR1 gene from multidrug-resistant KB cells. Here they report the construction of a full-length cDNA for the human MDR1 gene and show that this reconstructed cDNA, when inserted into a retroviral expression vector containing the long terminal repeats of Moloney leukemia virus or Harvey sarcoma virus, functions in mouse NIH 3T3 and human KB cells to confer the complete multidrug-resistance phenotype. These results suggest that the human MDR1 gene may be used as a positive selectable marker to introduce genes into human cells and to transform human cells to multidrug resistance without introducing nonhuman antigens

  10. UMMS-4 enhanced sensitivity of chemotherapeutic agents to ABCB1-overexpressing cells via inhibiting function of ABCB1 transporter.

    Qiao, Dongjuan; Tang, Shangjun; Aslam, Sana; Ahmad, Matloob; To, Kenneth Kin Wah; Wang, Fang; Huang, Zhencong; Cai, Jiye; Fu, Liwu

    2014-01-01

    Multidrug resistance (MDR) mediated by ATP-binding cassette (ABC) transporters through efflux of antineoplastic agents from cancer cells is a major obstacle to successful cancer chemotherapy. The inhibition of these ABC transporters is thus a logical approach to circumvent MDR. There has been intensive research effort to design and develop novel inhibitors for the ABC transporters to achieve this goal. In the present study, we evaluated the ability of UMMS-4 to modulate P-glycoprotein (P-gp/ABCB1)-, breast cancer resistance protein (BCRP/ABCG2)- and multidrug resistance protein (MRP1/ABCC1)-mediated MDR in cancer cells. Our findings showed that UMMS-4, at non-cytotoxic concentrations, apparently circumvents resistance to ABCB1 substrate anticancer drugs in ABCB1-overexpressing cells. When used at a concentration of 20 μmol/L, UMMS-4 produced a 17.53-fold reversal of MDR, but showed no effect on the sensitivity of drug-sensitive parental cells. UMMS-4, however, did not significantly alter the sensitivity of non-ABCB1 substrates in all cells and was unable to reverse ABCG2- and ABCC1-mediated MDR. Additionally, UMMS-4 profoundly inhibited the transport of rhodamine 123 (Rho 123) and doxorubicin (Dox) by the ABCB1 transporter. Furthermore, UMMS-4 did not alter the expression of ABCB1 at the mRNA and protein levels. In addition, the results of ATPase assays showed that UMMS-4 stimulated the ATPase activity of ABCB1. Taken together, we conclude that UMMS-4 antagonizes ABCB1-mediated MDR in cancer cells through direct inhibition of the drug efflux function of ABCB1. These findings may be useful for the development of safer and more effective MDR modulator. PMID:24660104

  11. Novel understanding of ABC transporters ABCB1/MDR/P-glycoprotein, ABCC2/MRP2, and ABCG2/BCRP in colorectal pathophysiology

    Andersen, Vibeke; Svenningsen, Katrine; Almind Knudsen, Lina; Hansen, Axel Kornerup; Holmskov, Uffe; Stensballe, Allan; Vogel, Ulla

    2015-01-01

    transporter proteins, inflammatory bowel disease, ulcerative, colitis, Crohns disease, colorectal cancer, colitis, intestinal inflammation, intestinal carcinogenesis, ABCB1/P-glycoprotein (P-gp/CD243/MDR1), ABCC2/multidrug resistance protein 2 (MRP2) and ABCG2/breast cancer resistance protein (BCRP), Abcb1....../Mdr1a, abcc2/Mrp2, abcg2/Bcrp, knock-out mice, tight junction, membrane lipid function. RESULTS: Recently, human studies reported that changes in the levels of ABC transporters were early events in the adenoma-carcinoma sequence leading to CRC. A link between ABCB1, high fat diet and gut microbes in...

  12. Expressions of MDR1, MRP, and Fas in acute leukemia and their clinical significance%急性白血病中MDR1 MRP和Fas表达及其临床意义

    李拴明; 叶芳; 郭宏锋; 麻生文

    2006-01-01

    目的研究多药耐药基因(MDR1)、多药耐药相关蛋白基因(MRP)和诱导凋亡的因子Fas在急性白血病(AL)的表达及它们与临床耐药的关系.方法采用流式细胞仪(FCM)直接免疫荧光法和半定量多聚酶链反应(RT-PCR)测定51例AL患者骨髓单个核细胞三种指标的表达情况.结果51例AL患者中MDR1/MRP/Fas三者共表达阳性率为11.76%,MDR1/MRP/Fas三者表达均阴性发生率为23.53%.三指标表达全阴性的患者75%获得完全缓解(CR),MDR+/MRP+/Fas+的患者84.21%获得CR,MDR+/MRP+/Fas-或MDR+/MRP+无一人CR(P<0.01).单指标分析表明MDR1、MRP和Fas表达阳性率分别为21.15%、32.69%和65.38%.MDR1阳性者CR率18.18%,明显低于MDR1阴性者72.50%(P<0.01);MRP阳性者CR率29.41%,明显低于MRP阴性者76.47%(P<0.01);Fas阳性者CR率63.64%,略高于Fas阴性者55.56%,但二者无显著性差异.结论MDR1+/MRP+或MDR1+/MRP+/Fas-者不易获CR,白血病患者的耐药除了与MDR1高表达密切相关外,还与非P-糖蛋白(P-gp)介导的MRP及Fas表达等因素相关.

  13. Evaluation of mRNA Expression Levels of cyp51A and mdr1, Candidate Genes for Voriconazole Resistance in Aspergillus flavus

    Fattahi, Azam; Zaini, Farideh; Kordbacheh, Parivash; Rezaie, Sasan; Safara, Mahin; Fateh, Roohollah; Farahyar, Shirin; Kanani, Ali; Heidari, Mansour

    2015-01-01

    Background: Voriconazole Resistance (VRC-R) in Aspergillus flavus isolates impacts the management of aspergillosis, since azoles are the first choice for prophylaxis and therapy. However, to the best of our knowledge, the mechanisms underlying voriconazole resistance are poorly understood. Objectives: The present study was designed to evaluate mRNA expression levels of cyp51A and mdr1 genes in voriconazole resistant A. flavus by a Real-Time Reverse Transcriptase Polymerase Chain Reaction (RT-...

  14. Changes of Tc-99m sestamibi uptake in P-glycoprotein expressing leukaemia cells treated in vivo with antisense oligodeoxynucleotide complementary to mdr1 mRNA

    We examined the feasibility of Tc-99m sestamibi to monitor changes of mRNA expression of MDRl/P-glycoprotein (Pgp) following antisense oligodeoxynucleotide (AS-ODN) treatment in vivo. Three days after the intraperitoneal inoculation of murine leukaemia P388/R cells expressing MDR1/P-gp in CDFI mice, 15-mer phosphorothioate ASODN to the initiation codon of mouse mdr1 mRNA was administered intraperitoneally at 10 mg/kg daily for 3 or 4 days. Cells collected from ascites were suspended in medium for Tc-99m sestamibi uptake studies. To know the duration of antisense effects, cells were harvested 2 days later after the 3-day treatment. AS-ODN treatment increased Tc-99m sestamibi uptake. Effects of 3-day treatment and 4-day treatment were the same. Treatment effects were not detected when uptake was observed 2 days after 3-day treatment. Based on the results it was concluded that in vivo treatment with AS-ODN specific to the coding portion of mdr1 mRNA increased Tc-99m sestamibi uptake in leukaemia cells possessing MDR function. (author)

  15. Expression of LRP and MDR1 in locally advanced breast cancer predicts axillary node invasion at the time of rescue mastectomy after induction chemotherapy

    Axillary node status after induction chemotherapy for locally advanced breast cancer has been shown on multivariate analysis to be an independent predictor of relapse. However, it has been postulated that responders to induction chemotherapy with a clinically negative axilla could be spared the burden of lymphadenectomy, because most of them will not show histological nodal invasion. P-glycoprotein expression in the rescue mastectomy specimen has finally been identified as a significant predictor of patient survival. We studied the expression of the genes encoding multidrug resistance associated protein (MDR1) and lung cancer associated resistance protein (LRP) in formalin-fixed, paraffin-embedded tumor samples from 52 patients treated for locally advanced breast cancer by means of induction chemotherapy followed by rescue mastectomy. P-glycoprotein expression was assessed by means of immunohistochemistry before treatment in 23 cases, and by means of reverse-transcriptase-mediated polymerase chain reaction (RT-PCR) after treatment in 46 (6 failed). LRP expression was detected by means of immunohistochemistry, with the LRP-56 monoclonal antibody, in 31 cases before treatment. Immunohistochemistry for detecting the expression of c-erb-B2, p53, Ki67, estrogen receptor and progesterone receptor are routinely performed in our laboratory in every case, and the results obtained were included in the study. All patients had received between two and six cycles of standard 5-fluorouracil, doxorubicin and cyclophosphamide (FAC) chemotherapy, with two exceptions [one patient received four cycles of a docetaxel-adriamycin combination, and the other four cycles of standard cyclophosphamide-methotrexate-5-fluorouracil (CMF) polychemotherapy]. Response was assessed in accordance with the Response Evaluation Criteria In Solid Tumors (RECIST). By these, 2 patients achieved a complete clinical response, 37 a partial response, and the remaining 13 showed stable disease. This makes a

  16. Drug resistance to paclitaxel is not only associated with ABCB1 mRNA expression but also with drug accumulation in intracellular compartments in human lung cancer cell lines.

    Shimomura, Masanori; Yaoi, Takeshi; Itoh, Kyoko; Kato, Daishiro; Terauchi, Kunihiko; Shimada, Junichi; Fushiki, Shinji

    2012-04-01

    In order to clarify the mechanisms of resistance to paclitaxel in lung cancer, three human lung cancer cell lines which exhibit different sensitivity to paclitaxel were investigated from the following viewpoints: overexpression of ATP-binding cassette, sub-family B, member 1 (ABCB1), mutations on paclitaxel binding site of β-tubulin genes, quantity of polymerized tubulin and the intracellular localization of paclitaxel. ABCB1 expression was evaluated by real-time RT-PCR. No correlations were noted between the ABCB1 expression in the sensitive and resistant cell lines at the mRNA level. No mutations on the paclitaxel binding site of the β-tubulin genes were detected in either the resistant or sensitive cells. Live cell images obtained by confocal laser microscopy revealed that the resistant cell line, RERF-LC-KJ, had more accumulation of Oregon Green® 488 conjugated paclitaxel in the lysosomal and extra-lysosomal compartments of cytoplasm than other cell lines. The results obtained in this study indicated that the changes in the subcellular localization could contribute to the production of paclitaxel resistance in lung cancer cell lines. Further studies should be conducted to elucidate the molecular mechanisms that differentiate the intracellular localization of paclitaxel. PMID:22179563

  17. Construction of Multi-ribozyme Expression System and Its Characterization of Cleavage on the MDR1/MRP1 Double Target Substrate in vitro

    TIAN Sheng-li; ZHENG Suo; LIU Shi-de; ZHANG Jian-hua; XU Dong-ping; OHNUMA Takao

    2009-01-01

    To improve catalytic activity of ribozyme on its substrate,the multi-ribozyme expression system was designed and constructed from 20 cis-acting hammerhead ribozymes undergoing self-cleavage with 10 trans-acting hammerhead ribozymes inserted altematively regularly and the plasmid of pGEM-MDRI/MRPI used to transcribe the M DRI/MRPI(196/210) substrate containing double target sites was also constructed by DNA recombination.Endonuclease digestion analysis and DNA sequencing indicate all the recombinant plasmids were correct.The cleavage activities were evaluated for the multi-ribozyme expression system on the MDR1/MRP1 substrate in the cell free system.The results demonstrate that the cis-acting hammerhead ribozymes in the multi-ribozyme expression system were able to cleave themselves and the 72 nt of 196Rz and the 71 nt of 210Rz trans-acting hammerhead ribozymes were liberated effectively,and the trans-acting hammerhead ribozymes released were able to act on the MDR1/MRP1 double target RNA substrate and cleave the target RNA at specific sites effectively.The multiribozyme expression system of the [Coat'A196Rz/Coat'B210Rz]5 is more significantly superior to that of the [Coat'A 196Rz/Coat'B210Rz]1 in cleavage of RNA substrate.The fractions cleaved by [Coat'A196Rz/Coat'B210Rz]5 on the MDR1/MRP1 substrate for 8 h at observed temperatures showed no marked difference.The studies of Mg2+ on cleavage efficiency indicate that cleavage reaction is dependent on Mg2+ ions concentration.The plot of Ig(kobs) vs.Igc(Mg2+) displays a linear relationship between 2.5 mmol/L and 20 mmol/L Mg2..It suggests that Mg2+ ions play a crucial role in multi-ribozyme cleavage on the substrate.

  18. The putative P-gp inhibitor telmisartan does not affect the transcellular permeability and cellular uptake of the calcium channel antagonist verapamil in the P-glycoprotein expressing cell line MDCK II MDR1

    Saaby, Lasse; Tfelt-Hansen, Peer; Brodin, Birger

    2015-01-01

    Verapamil is used in high doses for the treatment of cluster headache. Verapamil has been described as a P-glycoprotein (P-gp, ABCB1) substrate. We wished to evaluate in vitro whether co administration of a P-gp inhibitor with verapamil could be a feasible strategy for increasing CNS uptake of...... verapamil. Fluxes of radiolabelled verapamil across MDCK II MDR1 monolayers were measured in the absence and presence of the putative P-gp inhibitor telmisartan (a clinically approved drug compound). Verapamil displayed a vectorial basolateral-toapical transepithelial efflux across the MDCK II MDR1...... monolayers with a permeability of 5.7 9 105 cm sec1 compared to an apical to basolateral permeability of 1.3 9 105 cm sec-1. The efflux could be inhibited with the P-gp inhibitor zosuquidar. Zosuquidar (0.4 lmol/L) reduced the efflux ratio (PB-A/PA-B) for verapamil 4.6–1.6. The presence of telmisartan...

  19. JNK1/2 Activation by an Extract from the Roots of Morus alba L. Reduces the Viability of Multidrug-Resistant MCF-7/Dox Cells by Inhibiting YB-1-Dependent MDR1 Expression

    Youn Kyung Choi

    2013-01-01

    Full Text Available Cancer cells acquire anticancer drug resistance during chemotherapy, which aggravates cancer disease. MDR1 encoded from multidrug resistance gene 1 mainly causes multidrug resistance phenotypes of different cancer cells. In this study, we demonstrate that JNK1/2 activation by an extract from the root of Morus alba L. (White mulberry reduces doxorubicin-resistant MCF-7/Dox cell viability by inhibiting YB-1 regulation of MDR1 gene expression. When MCF-7 or MCF-7/Dox cells, where MDR1 is highly expressed were treated with an extract from roots or leaves of Morus alba L., respectively, the root extract from the mulberry (REM but not the leaf extract (LEM reduced cell viabilities of both MCF-7 and MCF-7/Dox cells, which was enhanced by cotreatment with doxorubicin. REM but not LEM further inhibited YB-1 nuclear translocation and its regulation of MDR1 gene expression. Moreover, REM promoted phosphorylation of c-Jun NH2-terminal kinase 1/2 (JNK1/2 and JNK1/2 inhibitor, SP600125 and rescued REM inhibition of both MDR1 expression and viabilities in MCF-7/Dox cells. Consistently, overexpression of JNK1, c-Jun, or c-Fos inhibited YB-1-dependent MDR1 expression and reduced viabilities in MCF-7/Dox cells. In conclusion, our data indicate that REM-activated JNK-cJun/c-Fos pathway decreases the viability of MCF-7/Dox cells by inhibiting YB-1-dependent MDR1 gene expression. Thus, we suggest that REM may be useful for treating multidrug-resistant cancer cells.

  20. Hernandezine, a Bisbenzylisoquinoline Alkaloid with Selective Inhibitory Activity against Multidrug-Resistance-Linked ATP-Binding Cassette Drug Transporter ABCB1.

    Hsiao, Sung-Han; Lu, Yu-Jen; Yang, Chun-Chiao; Tuo, Wei-Cherng; Li, Yan-Qing; Huang, Yang-Hui; Hsieh, Chia-Hung; Hung, Tai-Ho; Wu, Chung-Pu

    2016-08-26

    The overexpression of ATP-binding cassette (ABC) drug transporter ABCB1 (P-glycoprotein, MDR1) is the most studied mechanism of multidrug resistance (MDR), which remains a major obstacle in clinical cancer chemotherapy. Consequently, resensitizing MDR cancer cells by inhibiting the efflux function of ABCB1 has been considered as a potential strategy to overcome ABCB1-mediated MDR in cancer patients. However, the task of developing a suitable modulator of ABCB1 has been hindered mostly by the lack of selectivity and high intrinsic toxicity of candidate compounds. Considering the wide range of diversity and relatively nontoxic nature of natural products, developing a potential modulator of ABCB1 from natural sources is particularly valuable. Through screening of a large collection of purified bioactive natural products, hernandezine was identified as a potent and selective reversing agent for ABCB1-mediated MDR in cancer cells. Experimental data demonstrated that the bisbenzylisoquinoline alkaloid hernandezine is selective for ABCB1, effectively inhibits the transport function of ABCB1, and enhances drug-induced apoptosis in cancer cells. More importantly, hernandezine significantly resensitizes ABCB1-overexpressing cancer cells to multiple chemotherapeutic drugs at nontoxic, nanomolar concentrations. Collectively, these findings reveal that hernandezine has great potential to be further developed into a novel reversal agent for combination therapy in MDR cancer patients. PMID:27504669

  1. 甲胎蛋白对耐药基因MDR1表达及肝癌细胞化疗敏感性的影响%Influence of alpha-fetoprotein on the expression of drug-resistance gene MDR1 and chemotherapeutic sensitivity in hepatocellular carcinoma cells

    吴超; 杨健; 张金玲; 金涛; 何前进; 李常海

    2015-01-01

    Objective To explore the influence of alpha-fetoprotein (AFP) on the expression of drug-resistance gene MDR1 and chemotherapeutic sensitivity in hepatocellular carcinoma (HCC) cells.Methods A HCC cell line SMMC-7721/AFP, which was stably transfected with AFP gene, was established.mRNA and protein expressions of AFP and MDR1 were detected by real-time PCR and Western Blot,respectively.The sensitivity of SMMC-7721/AFP and SMMC-7721/EGFP cells with or without MDR1 silencing by siRNA to doxorubicin was tested by MTT assay.Immunohistochemistry was used to detect the expression of MDR1 genes-coded protein Pgp in 60 cases of HCC tissues, and the relationship between Pgp expression and serum AFP levels was analyzed.Results AFP mRNA and protein could be detected in SMMC-7721/AFP cells, but not in control cells, indicating that the AFP stably transfected cell line was successfully established.MDR1 mRNA and protein levels were higher in SMMC-7721/AFP cells than those in SMMC-7721/EGFP cells.MDR1 mRNA level in SMMC-7721/AFP cells was (52.7 ± 1.5) times as high as that in SMMC-7721/EGFP cells (P < 0.05).The resistance to doxorubicin was increased by (12.8 ± 1.1) times after AFP transfection (P < 0.05).The chemosensitivity to doxorubicin was increased after the expression of MDR1 was knocked down by siRNA.The expression of Pgp in HCC tissues was positively correlated with the serum AFP levels.Conclusion AFP could induce drug-resistance to doxorubicin in HCC cells by increasing the expression of MDR1.%目的 探讨甲胎蛋白(AFP)对耐药基因MDR1表达和肝癌细胞化疗敏感性的影响.方法 建立稳定表达AFP的肝癌细胞系SMMC-7721/AFP,分别通过Real-time PCR和蛋白印迹检测转染前后AFP和MDR1的表达.MTT法测定SMMC-7721/AFP和SMMC-7721/EGFP细胞对阿霉素的化疗敏感性.siRNA沉默SMMC-7721/AFP细胞中MDR1的表达,观察细胞对阿霉素化疗敏感性的变化.采用免疫组织化学染色法检测60例肝癌组织中MDR1编码蛋

  2. Downregulation of gene MDR1 by shRNA to reverse multidrug-resistance of ovarian cancer A2780 cells

    Hongyi Zhang; Jing Wang; Kai Cai; Longwei Jiang; Dandan Zhou; Cuiping Yang,; Junsong Chen,; Dengyu Chen,; Jun Dou

    2012-01-01

    Background: To explore the effects of downregulated multidrug-resistance P-glycoprotein (MDR1/ABCB1) and reversed multidrug-resistance in human A2780 ovarian cancer cells. Materials and Methods: Three shRNAs targeting the MDR1 gene were synthesized, and cloned into plasmid pSUPER-enhanced green fluorescent protein 1 (EGFP1). The formed pSUPER-EGFP1-MDR1-shRNAs were transfected into the A2780 cells, respectively, and the quantitative reverse transcription polymerase chain reaction and west...

  3. ABCB1 in children's brain tumours.

    Coyle, Beth; Kessler, Maya; Sabnis, Durgagauri H; Kerr, Ian D

    2015-10-01

    Tumours of the central nervous system are the most common solid tumour, accounting for a quarter of the 1500 cases of childhood cancer diagnosed each year in the U.K. They are the most common cause of cancer-related death in children. Treatment consists of surgery followed by adjuvant chemotherapy and/or radiotherapy. Survival rates have generally increased, but many survivors suffer from radiotherapy-related neurocognitive and endocrine side effects as well as an increased risk of secondary cancer. Adjuvant chemotherapy is normally given in combination to circumvent chemoresistance, but several studies have demonstrated it to be ineffective in the absence of radiotherapy. The identification of children with drug-resistant disease at the outset could allow stratification of those that are potentially curable by chemotherapy alone. Ultimately, however, what is required is a means to overcome this drug resistance and restore the effectiveness of chemotherapy. Medulloblastomas and ependymomas account for over 30% of paediatric brain tumours. Advances in neurosurgery, adjuvant radiotherapy and chemotherapy have led to improvements in 5-year overall survival rates. There remain, however, significant numbers of medulloblastoma patients that have intrinsically drug-resistant tumours and/or present with disseminated disease. Local relapse in ependymoma is also common and has an extremely poor prognosis with only 25% of children surviving first relapse. Each of these is consistent with the acquisition of drug and radiotherapy resistance. Since the majority of chemotherapy drugs currently used to treat these patients are transport substrates for ATP-binding cassette sub-family B member 1 (ABCB1) we will address the hypothesis that ABCB1 expression underlies this drug resistance. PMID:26517917

  4. Inhibition of mTORC2 Induces Cell-Cycle Arrest and Enhances the Cytotoxicity of Doxorubicin by Suppressing MDR1 Expression in HCC Cells.

    Chen, Bryan Wei; Chen, Wei; Liang, Hui; Liu, Hao; Liang, Chao; Zhi, Xiao; Hu, Li-Qiang; Yu, Xia-Zhen; Wei, Tao; Ma, Tao; Xue, Fei; Zheng, Lei; Zhao, Bin; Feng, Xin-Hua; Bai, Xue-Li; Liang, Ting-Bo

    2015-08-01

    mTOR is aberrantly activated in hepatocellular carcinoma (HCC) and plays pivotal roles in tumorigenesis and chemoresistance. Rapamycin has been reported to exert antitumor activity in HCC and sensitizes HCC cells to cytotoxic agents. However, due to feedback activation of AKT after mTOR complex 1 (mTORC1) inhibition, simultaneous targeting of mTORC1/2 may be more effective. In this study, we examined the interaction between the dual mTORC1/2 inhibitor OSI-027 and doxorubicin in vitro and in vivo. OSI-027 was found to reduce phosphorylation of both mTORC1 and mTORC2 substrates, including 4E-BP1, p70S6K, and AKT (Ser473), and inhibit HCC cell proliferation. Similar to OSI-027 treatment, knockdown of mTORC2 induced G0-G1 phase cell-cycle arrest. In contrast, rapamycin or knockdown of mTORC1 increased phosphorylation of AKT (Ser473), yet had little antiproliferative effect. Notably, OSI-027 synergized with doxorubicin for the antiproliferative efficacy in a manner dependent of MDR1 expression in HCC cells. The synergistic antitumor effect of OSI-027 and doxorubicin was also observed in a HCC xenograft mouse model. Moreover, AKT was required for OSI-027-induced cell-cycle arrest and downregulation of MDR1. Our findings provide a rationale for dual mTORC1/mTORC2 inhibitors, such as OSI-027, as monotherapy or in combination with cytotoxic agents to treat HCC. Mol Cancer Ther; 14(8); 1805-15. ©2015 AACR. PMID:26026051

  5. Purvalanol A, olomoucine II and roscovitine inhibit ABCB1 transporter and synergistically potentiate cytotoxic effects of daunorubicin in vitro.

    Daniela Cihalova

    Full Text Available Cyclin-dependent kinase inhibitors (CDKi have high potential applicability in anticancer therapy, but various aspects of their pharmacokinetics, especially their interactions with drug efflux transporters, have not yet been evaluated in detail. Thus, we investigated interactions of five CDKi (purvalanol A, olomoucine II, roscovitine, flavopiridol and SNS-032 with the ABCB1 transporter. Four of the compounds inhibited efflux of two ABCB1 substrates, Hoechst 33342 and daunorubicin, in MDCKII-ABCB1 cells: Olomoucine II most strongly, followed by roscovitine, purvalanol A, and flavopiridol. SNS-032 inhibited ABCB1-mediated efflux of Hoechst 33342 but not daunorubicin. In addition, purvalanol A, SNS-032 and flavopiridol lowered the stimulated ATPase activity in ABCB1 membrane preparations, while olomoucine II and roscovitine not only inhibited the stimulated ATPase but also significantly activated the basal ABCB1 ATPase, suggesting that these two CDKi are ABCB1 substrates. We further revealed that the strongest ABCB1 inhibitors (purvalanol A, olomoucine II and roscovitine synergistically potentiate the antiproliferative effect of daunorubicin, a commonly used anticancer drug and ABCB1 substrate, in MDCKII-ABCB1 cells as well as in human carcinoma HCT-8 and HepG2 cells. We suggest that this pronounced synergism is at least partly caused by (i CDKi-mediated inhibition of ABCB1 transporter leading to increased intracellular retention of daunorubicin and (ii native cytotoxic activity of the CDKi. Our results indicate that co-administration of the tested CDKi with anticancer drugs that are ABCB1 substrates may allow significant dose reduction in the treatment of ABCB1-expressing tumors.

  6. Epigenetic modulation of the drug resistance genes MGMT, ABCB1 and ABCG2 in glioblastoma multiforme

    2013-01-01

    Background Resistance of the highly aggressive glioblastoma multiforme (GBM) to drug therapy is a major clinical problem resulting in a poor patient’s prognosis. Beside promoter methylation of the O 6 -methylguanine-DNA-methyltransferase (MGMT) gene the efflux transporters ABCB1 and ABCG2 have been suggested as pivotal factors contributing to drug resistance, but the methylation of ABCB1 and ABCG2 has not been assessed before in GBM. Methods Therefore, we evaluated the proportion and prognostic significance of promoter methylation of MGMT, ABCB1 and ABCG2 in 64 GBM patient samples using pyrosequencing technology. Further, the single nucleotide polymorphisms MGMT C-56 T (rs16906252), ABCB1 C3435T (rs1045642) and ABCG2 C421A (rs2231142) were determined using the restriction fragment length polymorphism method (RFLP). To study a correlation between promoter methylation and gene expression, we analyzed MGMT, ABCB1 and ABCG2 expression in 20 glioblastoma and 7 non-neoplastic brain samples. Results Despite a significantly increased MGMT and ABCB1 promoter methylation in GBM tissue, multivariate regression analysis revealed no significant association between overall survival of glioblastoma patients and MGMT or ABCB1 promoter methylation. However, a significant negative correlation between promoter methylation and expression could be identified for MGMT but not for ABCB1 and ABCG2. Furthermore, MGMT promoter methylation was significantly associated with the genotypes of the MGMT C-56 T polymorphism showing a higher methylation level in the T allele bearing GBM. Conclusions In summary, the data of this study confirm the previous published relation of MGMT promoter methylation and gene expression, but argue for no pivotal role of MGMT, ABCB1 and ABCG2 promoter methylation in GBM patients’ survival. PMID:24380367

  7. Novel retroviral vectors for efficient expression of the multidrug resistance (mdr-1) gene in early hematopoietic cells.

    Baum, C; Hegewisch-Becker, S; Eckert, H G; Stocking, C; Ostertag, W

    1995-01-01

    We present data that retroviral gene expression in early hematopoietic cells is subjected to transcriptional controls similar to those previously described for embryonic stem cells. Transient transfection experiments revealed that both the viral enhancer region in the U3 region of the long terminal repeat as well as a repressor element coincident with the primer binding site of Moloney leukemia viruses are limiting for expression in hematopoietic cells in a differentiation-dependent manner. W...

  8. Tangeretin, a citrus pentamethoxyflavone, antagonizes ABCB1-mediated multidrug resistance by inhibiting its transport function.

    Feng, Sen-Ling; Yuan, Zhong-Wen; Yao, Xiao-Jun; Ma, Wen-Zhe; Liu, Liang; Liu, Zhong-Qiu; Xie, Ying

    2016-08-01

    Multidrug resistance (MDR) and tumor metastasis are the main causes of chemotherapeutic treatment failure and mortality in cancer patients. In this study, at achievable nontoxic plasma concentrations, citrus flavonoid tangeretin has been shown to reverse ABCB1-mediated cancer resistance to a variety of chemotherapeutic agents effectively. Co-treatment of cells with tangeretin and paclitaxel activated apoptosis as well as arrested cell cycle at G2/M-phase. Tangeretin profoundly inhibited the ABCB1 transporter activity since it significantly increased the intracellular accumulation of doxorubicin, and flutax-2 in A2780/T cells and decreased the efflux of ABCB1 substrates in Caco2 cells without altering the expression of ABCB1. Moreover, it stimulated the ATPase activity and inhibited verapamil-stimulated ATPase activity in a concentration-dependent manner, indicating a direct interaction with the transporter. The molecular docking results indicated a favorable binding of tangeretin with the transmemberane region site 1 of homology modeled ABCB1 transporter. The overall results demonstrated that tangeretin could sensitize ABCB1-overexpressing cancer cells to chemotherapeutical agents by directly inhibiting ABCB1 transporter function, which encouraged further animal and clinical studies in the treatment of resistant cancers. PMID:27058921

  9. Acquisition of docetaxel resistance in breast cancer cells reveals upregulation of ABCB1 expression as a key mediator of resistance accompanied by discrete upregulation of other specific genes and pathways

    Ninel Hansen, Stine; Westergaard, David; Borg Houlberg Thomsen, Mathilde;

    2015-01-01

    analysis singled out ABCB1, which encodes permeability glycoprotein (Pgp), as the top upregulated gene in both MCF7RES and MDARES. Functional validation revealed Pgp as a key resistance mediator at low docetaxel concentrations (first-phase response), whereas additional resistance mechanisms appeared to be...... resistance and thereby identify key molecular mechanisms and predictive molecular characteristics to docetaxel resistance. Two docetaxel-resistant cell lines, MCF7RES and MDARES, were generated from their respective parental cell lines MCF-7 and MDA-MB-231 by stepwise selection in docetaxel dose increments...... prominent at higher docetaxel concentrations (second-phase response). Additional resistance mechanisms were indicated by gene expression profiling, including genes in the interferon-inducible protein family in MCF7RES and cancer testis antigen family in MDARES. Also, upregulated expression of various ABC...

  10. Dual regulation of P-glycoprotein expression by Trichostatin A in cancer cell lines

    Balaguer Trinidad

    2012-07-01

    Full Text Available Abstract Background It has been reported that the histone deacetylase inhibitor (iHDAc trichostatin A (TSA induces an increase in MDR1 gene transcription (ABCB1. This result would compromise the use of iHDACs in combination with other cytotoxic agents that are substrates of P-glycoprotein (Pgp. It has also been reported the use of alternative promoters by the ABCB1 gene and the existence of a translational control of Pgp protein. Finally, the ABCB1 gene is located in a genetic locus with the nested gene RUNDC3B in the complementary DNA strand, raising the possibility that RUNDC3B expression could interfere with ABCB1 alternative promoter regulation. Methods A combination of RT-PCR, real time RT-PCR, Western blot and drug accumulation assays by flow cytometry has been used in this study. Results The iHDACs-induced increase in MDR1 mRNA levels is not followed by a subsequent increase in Pgp protein levels or activity in several pancreatic and colon carcinoma cell lines, suggesting a translational control of Pgp in these cell lines. In addition, the MDR1 mRNA produced in these cell lines is shorter in its 5′ end that the Pgp mRNA produced in cell lines expressing Pgp protein. The different size of the Pgp mRNA is due to the use of alternative promoters. We also demonstrate that these promoters are differentially regulated by TSA. The translational blockade of Pgp mRNA in the pancreatic carcinoma cell lines could be related to alterations in the 5′ end of the MDR1 mRNA in the Pgp protein expressing cell lines. In addition, we demonstrate that the ABCB1 nested gene RUNDC3B expression although upregulated by TSA is independent of the ABCB1 alternative promoter used. Conclusions The results show that the increase in MDR1 mRNA expression after iHDACs treatment is clinically irrelevant since this mRNA does not render an active Pgp protein, at least in colon and pancreatic cancer cell lines. Furthermore, we demonstrate that TSA in fact, regulates

  11. Die Bedeutung der ABC-Transportsysteme ABCB1 und Abcb11 in der Arzneimitteltherapie und bei cholestatischen Lebererkrankungen

    Gerloff, Thomas

    2004-01-01

    ABC-Transmembrantransporter sind an der Aufnahme, Verteilung und Ausscheidung vieler Arznei- und Fremdstoffe beteiligt. Sie spielen eine Schlüsselrolle in der Pharmakokinetik und in der Ausscheidung toxischer endogener oder exogener Substanzen. Das Ziel der hier präsentierten Untersuchungen war deshalb, den Einfluss genetischer Polymorphismen des bekanntesten Vertreters dieser Proteinfamilie, MDR1 (ABCB1) zu untersuchen. Darüberhinaus sollte der ebenfalls zur ABC-Transporterfamilie gehörende ...

  12. Canine mdr1 gene mutation in Japan.

    Kawabata, Akiko; Momoi, Yasuyuki; Inoue-Murayama, Miho; Iwasaki, Toshiroh

    2005-11-01

    Frequency of the 4-bp deletion mutant in canine mdr1 gene was examined in 193 dogs of eight breeds in Japan. The mutant allele was found in Collies, Australian Shepherds, and Shetland Sheepdogs, where its respective frequencies were 58.3%, 33.3%, and 1.2%. The MDR1 protein was detected on peripheral blood mononuclear cells (PBMC) from a MDR1/MDR1 dog, but not on PBMC from a mdr1-1Delta/mdr1-1Delta Collie. Rhodamine 123 was extruded from MDR1/MDR1 lymphocytes. That excretion was inhibited by a MDR1 inhibitor, verapamil. On the other hand, Rh123 excretion was not observed from lymphocytes derived from a mdr1-1Delta/mdr1-1Delta Collie. These results indicated that the mutant mdr1 allele also existed in Collie-breed dogs in Japan at high rates and that mdr1-1Delta /mdr1-1Delta dogs have no functional MDR1. PMID:16327220

  13. Expression of a full-length cDNA for the human "MDR1" gene confers resistance to colchicine, doxorubicin, and vinblastine.

    Ueda, K; Cardarelli, C; Gottesman, M M; Pastan, I

    1987-01-01

    Intrinsic and acquired multidrug resistance (MDR) is an important problem in cancer therapy. MDR in human KB carcinoma cells selected for resistance to colchicine, vinblastine, or doxorubicin (former generic name adriamycin) is associated with overexpression of the "MDR1" gene, which encodes P-glycoprotein. We previously have isolated an overlapping set of cDNA clones for the human MDR1 gene from multidrug-resistant KB cells. Here we report the construction of a full-length cDNA for the human...

  14. Detection of heterozygous MDR1 nt230(del4 mutation in a mixed-breed dog: case report of possible doxorubicin toxicosis

    Monobe MM

    2013-10-01

    Full Text Available Marina Mitie Monobe,1 Kari V Lunsford,2 João Pessoa Araújo Jr,3 Camilo Bulla41Department of Veterinary Clinics, School of Veterinary Medicine and Animal Science, Sao Paulo State University, Botucatu, Brazil; 2Department of Clinical Sciences and Animal Health Center, College of Veterinary Medicine, Mississippi State University, MS, USA; 3Department of Microbiology and Immunology, Biosciences Institute, Sao Paulo State University, Botucatu, Brazil; 4Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, MS, USAAbstract: P-glycoprotein (ABCB1, the product of the Multidrug Resistance Gene (MDR1 (ABCB1 gene, is the major multidrug transporter contributing to the barrier function of several tissues and organs, including the brain. A four base pair deletion mutation in MDR1 results in the absence of a functional form of ABCB1 and loss of its protective function. Severe intoxication with the ABCB1 substrate, such as with anticancer drugs, has been attributed to genetic lack of functional ABCB1. This mutation has been detected in more than 10 dog breeds as well as in mixed-breed dogs living in different countries. In Brazil, evaluation for this mutation is not as widely available and is rarely used by veterinarians, so drug intoxication may be underdiagnosed. This is the first report from Brazil of doxorubicin neurotoxicity in a mixed-breed dog with the MDR1 nt230(del4 mutation.Keywords: canine, toxicology, cancer, P-glycoprotein

  15. ATP-binding cassette subfamily B member 1 (ABCB1) and subfamily C member 10 (ABCC10) are not primary resistance factors for cabazitaxel

    Rishil J Kathawala; Yi-Jun Wang; Suneet Shukla; Yun-Kai Zhang; Saeed Alqahtani; Amal Kaddoumi; Suresh V Ambudkar; Charles R Ashby Jr; Zhe-Sheng Chen

    2015-01-01

    Introduction:ATP-binding cassette subfamily B member 1 (ABCB1) and subfamily C member 10 (ABCC10) proteins are efflux transporters that couple the energy derived from ATP hydrolysis to the translocation of toxic substances and chemotherapeutic drugs out of cells. Cabazitaxel is a novel taxane that differs from paclitaxel by its lower affinity for ATP-binding cassette (ABC) transporters. Methods:We determined the effects of cabazitaxel, a novel tubulin-binding taxane, and paclitaxel on paclitaxel-resistant, ABCB1-overexpressing KB-C2 and LLC-MDR1-WT cells and paclitaxel-resistant, ABCC10-overexpressing HEK293/ABCC10 cells by calculating the degree of drug resistance and measuring ATPase activity of the ABCB1 transporter. Results:Decreased resistance to cabazitaxel compared with paclitaxel was observed in KB-C2, LLC-MDR1-WT, and HEK293/ABCC10 cells. Moreover, cabazitaxel had low efficacy, whereas paclitaxel had high efficacy in stimulating the ATPase activity of ABCB1, indicating a direct interaction of both drugs with the transporter. Conclusion:ABCB1 and ABCC10 are not primary resistance factors for cabazitaxel compared with paclitaxel, suggesting that cabazitaxel may have a low affinity for these efflux transporters.

  16. Changes in the expression of miR-381 and miR-495 are inversely associated with the expression of the MDR1 gene and development of multi-drug resistance.

    Yan Xu

    Full Text Available Multidrug resistance (MDR frequently develops in cancer patients exposed to chemotherapeutic agents and is usually brought about by over-expression of P-glycoprotein (P-gp which acts as a drug efflux pump to reduce the intracellular concentration of the drug(s. Thus, inhibiting P-gp expression might assist in overcoming MDR in cancer chemotherapy. MiRNAome profiling using next-generation sequencing identified differentially expressed microRNAs (miRs between parental K562 cells and MDR K562 cells (K562/ADM induced by adriamycin treatment. Two miRs, miR-381 and miR-495, that were strongly down-regulated in K562/ADM cells, are validated to target the 3'-UTR of the MDR1 gene. These miRs are located within a miR cluster located at chromosome region 14q32.31, and all miRs in this cluster appear to be down-regulated in K562/ADM cells. Functional analysis indicated that restoring expression of miR-381 or miR-495 in K562/ADM cells was correlated with reduced expression of the MDR1 gene and its protein product, P-gp, and increased drug uptake by the cells. Thus, we have demonstrated that changing the levels of certain miR species modulates the MDR phenotype in leukemia cells, and propose further exploration of the use of miR-based therapies to overcome MDR.

  17. Saracatinib (AZD0530) is a potent modulator of ABCB1-mediated multidrug resistance in vitro and in vivo.

    Liu, Ke-Jun; He, Jie-Hua; Su, Xiao-Dong; Sim, Hong-May; Xie, Jing-Dun; Chen, Xing-Gui; Wang, Fang; Liang, Yong-Ju; Singh, Satyakam; Sodani, Kamlesh; Talele, Tanaji T; Ambudkar, Suresh V; Chen, Zhe-Sheng; Wu, Hai-Ying; Fu, Li-Wu

    2013-01-01

    Saracatinib, a highly selective, dual Src/Abl kinase inhibitor, is currently in a Phase II clinical trial for the treatment of ovarian cancer. In our study, we investigated the effect of saracatinib on the reversal of multidrug resistance (MDR) induced by ATP-binding cassette (ABC) transporters in vitro and in vivo. Our results showed that saracatinib significantly enhanced the cytotoxicity of ABCB1 substrate drugs in ABCB1 overexpressing HeLa/v200, MCF-7/adr and HEK293/ABCB1 cells, an effect that was stronger than that of gefitinib, whereas it had no effect on the cytotoxicity of the substrates in ABCC1 overexpressing HL-60/adr cells and its parental sensitive cells. Additionally, saracatinib significantly increased the doxorubicin (Dox) and Rho 123 accumulation in HeLa/v200 and MCF-7/adr cells, whereas it had no effect on HeLa and MCF-7 cells. Furthermore, saracatinib stimulated the ATPase activity and inhibited photolabeling of ABCB1 with [(125)I]-iodoarylazidoprazosin in a concentration-dependent manner. In addition, the homology modeling predicted the binding conformation of saracatinib within the large hydrophobic drug-binding cavity of human ABCB1. However, neither the expression level of ABCB1 nor the phosphorylation level of Akt was altered at the reversal concentrations of saracatinib. Importantly, saracatinib significantly enhanced the effect of paclitaxel against ABCB1-overexpressing HeLa/v200 cancer cell xenografts in nude mice. In conclusion, saracatinib reverses ABCB1-mediated MDR in vitro and in vivo by directly inhibiting ABCB1 transport function, without altering ABCB1 expression or AKT phosphorylation. These findings may be helpful to attenuate the effect of MDR by combining saracatinib with other chemotherapeutic drugs in the clinic. PMID:22623106

  18. Selective Toxicity of NSC 73306 in MDR1-positive cells as a New Strategy to Circumvent Multidrug Resistance in Cancer

    Ludwig, Joseph A.; Szakács, Gergely; Martin, Scott E.; Chu, Benjamin F.; Cardarelli, Carol; Sauna, Zuben E.; Caplen, Natasha J.; Fales, Henry M.; Ambudkar, Suresh V.; Weinstein, John N.; Gottesman, Michael M.

    2006-01-01

    ATP-binding cassette (ABC) proteins include the best known mediators of resistance to anticancer drugs. In particular, ABCB1 (MDR1/P-gp) extrudes many types of drugs from cancer cells, thereby conferring resistance to those agents. Attempts to overcome P-gp-mediated drug resistance using specific inhibitors of P-gp has had limited success, and has faced many therapeutic challenges. As an alternative approach to using P-gp inhibitors, we characterize a thiosemicarbazone derivative (NSC73306) i...

  19. Brief Report: High Peak Level of Plasma Raltegravir Concentration in Patients With ABCB1 and ABCG2 Genetic Variants.

    Tsuchiya, Kiyoto; Hayashida, Tsunefusa; Hamada, Akinobu; Oka, Shinichi; Gatanaga, Hiroyuki

    2016-05-01

    Raltegravir was recently identified to be a substrate of ATP-binding cassette transporter B1 (ABCB1) and G2 (ABCG2), which are efflux transporters and expressed in the intestines. We analyzed the relations between plasma raltegravir concentrations and single nucleotide polymorphism of ABCB1 and ABCG2 genes. The peak plasma concentration of raltegravir was significantly higher in the patients with ABCB1 4036 AG/GG and ABCG2 421 CA/AA than in other genotype holders (P = 0.0052), though no difference was identified in trough raltegravir concentrations, which may be explained by reduced expression of efflux transporters in intestine by these genetic variants. PMID:27097364

  20. Screening compounds with a novel high-throughput ABCB1-mediated efflux assay identifies drugs with known therapeutic targets at risk for multidrug resistance interference.

    Megan R Ansbro

    Full Text Available ABCB1, also known as P-glycoprotein (P-gp or multidrug resistance protein 1 (MDR1, is a membrane-associated multidrug transporter of the ATP-binding cassette (ABC transporter family. It is one of the most widely studied transporters that enable cancer cells to develop drug resistance. Reliable high-throughput assays that can identify compounds that interact with ABCB1 are crucial for developing new therapeutic drugs. A high-throughput assay for measuring ABCB1-mediated calcein AM efflux was developed using a fluorescent and phase-contrast live cell imaging system. This assay demonstrated the time- and dose-dependent accumulation of fluorescent calcein in ABCB1-overexpressing KB-V1 cells. Validation of the assay was performed with known ABCB1 inhibitors, XR9576, verapamil, and cyclosporin A, all of which displayed dose-dependent inhibition of ABCB1-mediated calcein AM efflux in this assay. Phase-contrast and fluorescent images taken by the imaging system provided additional opportunities for evaluating compounds that are cytotoxic or produce false positive signals. Compounds with known therapeutic targets and a kinase inhibitor library were screened. The assay identified multiple agents as inhibitors of ABCB1-mediated efflux and is highly reproducible. Among compounds identified as ABCB1 inhibitors, BEZ235, BI 2536, IKK 16, and ispinesib were further evaluated. The four compounds inhibited calcein AM efflux in a dose-dependent manner and were also active in the flow cytometry-based calcein AM efflux assay. BEZ235, BI 2536, and IKK 16 also successfully inhibited the labeling of ABCB1 with radiolabeled photoaffinity substrate [(125I]iodoarylazidoprazosin. Inhibition of ABCB1 with XR9576 and cyclosporin A enhanced the cytotoxicity of BI 2536 to ABCB1-overexpressing cancer cells, HCT-15-Pgp, and decreased the IC50 value of BI 2536 by several orders of magnitude. This efficient, reliable, and simple high-throughput assay has identified ABCB1

  1. Regulation of ABCB1/PGP1-catalysed auxin transport by linker phosphorylation

    Henrichs, Sina; Wang, Bangjun; Fukao, Yoichiro;

    2012-01-01

    Polar transport of the plant hormone auxin is controlled by PIN-and ABCB/PGP-efflux catalysts. PIN polarity is regulated by the AGC protein kinase, PINOID (PID), while ABCB activity was shown to be dependent on interaction with the FKBP42, TWISTED DWARF1 (TWD1). Using co-immunoprecipitation (co......-IP) and shotgun LC-MS/MS analysis, we identified PID as a valid partner in the interaction with TWD1. In-vitro and yeast expression analyses indicated that PID specifically modulates ABCB1-mediated auxin efflux in an action that is dependent on its kinase activity and that is reverted by quercetin binding...... and thus inhibition of PID autophosphorylation. Triple ABCB1/PID/TWD1 co-transfection in tobacco revealed that PID enhances ABCB1-mediated auxin efflux but blocks ABCB1 in the presence of TWD1. Phospho-proteomic analyses identified S634 as a key residue of the regulatory ABCB1 linker and a very likely...

  2. MDR1 mediated chemoresistance: BMI1 and TIP60 in action.

    Banerjee Mustafi, Soumyajit; Chakraborty, Prabir Kumar; Naz, Sarwat; Dwivedi, Shailendra Kumar Dhar; Street, Mark; Basak, Rumki; Yang, Da; Ding, Kai; Mukherjee, Priyabrata; Bhattacharya, Resham

    2016-08-01

    Chemotherapy-induced emergence of drug resistant cells is frequently observed and is exemplified by the expression of family of drug resistance proteins including, multidrug resistance protein 1 (MDR1). However, a concise mechanism for chemotherapy-induced MDR1 expression is unclear. Mechanistically, mutational selection, epigenetic alteration, activation of the Wnt pathway or impaired p53 function have been implicated. The present study describes that the surviving fraction of cisplatin resistant cells co- upregulate MDR1, BMI1 and acetyl transferase activity of TIP60. Using complementary gain and loss of function approaches, we demonstrate that the expression of MDR1 is positively regulated by BMI1, a stem-cell factor classically known as a transcriptional repressor. Our study establishes a functional interaction between TIP60 and BMI-1 resulting in upregulation of MDR1 expression. Chromatin immunoprecipitation (ChIP) assays further establish that the proximal MDR1 promoter responds to cisplatin in a BMI1 dependent manner. BMI1 interacts with a cluster of E-box elements on the MDR1 promoter and recruits TIP60 resulting in acetylation of histone H2A and H3. Collectively, our data establish a hitherto unknown liaison among MDR1, BMI1 and TIP60 and provide mechanistic insights into cisplatin-induced MDR1 expression resulting in acquired cross-resistance against paclitaxel, doxorubicin and likely other drugs. In conclusion, our results advocate utilizing anti-BMI1 strategies to alleviate acquired resistance to chemotherapy. PMID:27295567

  3. Association of ABCB1 genetic variants with renal function in Africans and in Caucasians

    Elston Robert C

    2008-06-01

    Full Text Available Abstract Background The P-glycoprotein, encoded by the ABCB1 gene, is expressed in human endothelial and mesangial cells, which contribute to control renal plasma flow and glomerular filtration rate. We investigated the association of ABCB1 variants with renal function in African and Caucasian subjects. Methods In Africans (290 subjects from 62 pedigrees, we genotyped the 2677G>T and 3435 C>T ABCB1 polymorphisms. Glomerular filtration rate (GFR was measured using inulin clearance and effective renal plasma flow (ERPF using para-aminohippurate clearance. In Caucasians (5382 unrelated subjects, we analyzed 30 SNPs located within and around ABCB1, using data from the Affymetrix 500 K chip. GFR was estimated using the simplified Modification of the Diet in Renal Disease (MDRD and Cockcroft-Gault equations. Results In Africans, compared to the reference genotype (GG or CC, each copy of the 2677T and 3435T allele was associated, respectively, with: GFR higher by 10.6 ± 2.9 (P P = 0.06 mL/min; ERPF higher by 47.5 ± 11.6 (P P = 0.007 mL/min; and renal resistances lower by 0.016 ± 0.004 (P P = 0.004 mm Hg/mL/min. In Caucasians, we identified 3 polymorphisms in the ABCB1 gene that were strongly associated with all estimates of GFR (smallest P value = 0.0006, overall P = 0.014 after multiple testing correction. Conclusion Variants of the ABCB1 gene were associated with renal function in both Africans and Caucasians and may therefore confer susceptibility to nephropathy in humans. If confirmed in other studies, these results point toward a new candidate gene for nephropathy in humans.

  4. The multidrug resistance 1 (MDR1) gene polymorphism G-rs3789243-A is not associated with disease susceptibility in Norwegian patients with colorectal adenoma and colorectal cancer; a case control study

    Andersen, V.; Agerstjerne, L.; Jensen, D.;

    2009-01-01

    Background: Smoking, dietary factors, and alcohol consumption are known life style factors contributing to gastrointestinal carcinogenesis. Genetic variations in carcinogen handling may affect cancer risk. The multidrug resistance 1(MDR1/ABCB1) gene encodes the transport protein P-glycoprotein (a...

  5. Multi-drug resistance gene (MDR1 and opioid analgesia in horses Gene de resistência múltipla aos fármacos e analgesia opióide em eqüinos

    Cláudio Corrêa Natalini

    2006-02-01

    Full Text Available Opioid absorption in the intestinal tract as well as its effects in the central nervous system is modulated by the P-glycoprotein (P-gp encoded in the Multi-drug Resistance gene (MDR1 also named ATP-binding cassete, subfamily B, member 1 (ABCB1. This MDR1 gene acts as a selective pump. The expression of this protein in humans and rodents inhibits cellular uptake of substrate opioids. The presence of the intestinal iso-enzyme CYP3A4 associated with MDR1 gene decreases the opioid analgesic activity due to an increase in intestinal metabolism, with a predicted intestinal first pass extraction around 20% which significantly influences the oral availability of opioids. In the central nervous system, P-gp expression decreases opioid neuronal uptake diminishing the analgesic effects. It is unknown if horses have the MDR1 gene and P-gp and what are the effects on opioid absorption, metabolism, and analgesia. Identifying the MDR1 gene and P-gp status in horses is of great importance in order to better understand opioid pharmacologic effects in horses.A absorção de opióides no trato intestinal, assim como seus efeitos no sistema nervoso central, são modulados pela P-glicoproteína (P-gp, uma proteína de membrana celular codificada pelo gene MDR1, também chamado ATP-binding cassete, subfamília B, membro 1 (ABCB1 e que atua como bomba seletiva. A expressão desta proteína em roedores e seres humanos inibe a absorção celular de opióides e sua presença no intestino associada à isoenzima CYP3A4 reduz a atividade analgésica dos opióides por ativação do metabolismo intestinal do fármaco. A redução na extração intestinal de fármacos opióides susceptíveis a esta proteína chega a 20%, o que reduz significativamente a biodisponibilidade de opióides administrados por via oral. No sistema nervoso central, a P-gp diminui a captação neuronal dos opióides e seus efeitos analgésicos. Ainda é desconhecido se o gene MDR1 e a P-gp est

  6. The prevalence of ABCB1:c.227_230delATAG mutation in affected dog breeds from European countries.

    Firdova, Zuzana; Turnova, Evelina; Bielikova, Marcela; Turna, Jan; Dudas, Andrej

    2016-06-01

    Deletion of 4-base pairs in the canine ABCB1 (MDR1) gene, responsible for encoding P-glycoprotein, leads to nonsense frame-shift mutation, which causes hypersensitivity to macrocyclic lactones drugs (e.g. ivermectin). To date, at least 12 purebred dog breeds have been found to be affected by this mutation. The aim of this study was to update information about the prevalence of ABCB1 mutation (c.227_230delATAG) in predisposed breeds in multiple European countries. This large scale survey also includes countries which were not involved in previous studies. The samples were collected in the period from 2012 to 2014. The overview is based on genotyping data of 4729 individuals. The observed mutant allele frequencies were 58.5% (Smooth Collie), 48.3% (Rough Collie), 35% (Australian Shepherd), 30.3% (Shetland Sheepdog), 28.1% (Silken Windhound), 26.1% (Miniature Australian Shepherd), 24.3% (Longhaired Whippet), 16.2% (White Swiss Shepherd) and 0% (Border Collie). The possible presence of an ABCB1 mutant allele in Akita-Inu breed has been investigated with negative results. This information could be helpful for breeders in optimization of their breeding strategy and for veterinarians when prescribing drug therapy for dogs of predisposed breeds. PMID:27234542

  7. Ferulic acid reverses ABCB1-mediated paclitaxel resistance in MDR cell lines.

    Muthusamy, Ganesan; Balupillai, Agilan; Ramasamy, Karthikeyan; Shanmugam, Mohana; Gunaseelan, Srithar; Mary, Beaulah; Prasad, N Rajendra

    2016-09-01

    Multidrug resistance (MDR) remains a major obstacle in cancer chemotherapy. The use of the dietary phytochemicals as chemosensitizing agents to enhance the efficacy of conventional cytostatic drugs has recently gained the attention as a plausible approach for overcoming the drug resistance. The aim of this study was to investigate whether a naturally occurring diet-based phenolic acid, ferulic acid, could sensitize paclitaxel efficacy in ABCB1 overexpressing (P-glycoprotein) colchicine selected KB Ch(R)8-5 cell line. In vitro drug efflux assays demonstrated that ferulic acid inhibits P-glycoprotein transport function in drug resistant KB Ch(R)8-5 cell lines. However, ferulic acid significantly downregulates ABCB1 expression in a concentration dependent manner. Cytotoxicity assay reveals that ferulic acid decreased paclitaxel resistance in KBCh(R)8-5 and HEK293/ABCB1 cells, which indicates its chemosensitizing potential. Clonogenic cell survival assay and apoptotic morphological staining further confirm the chemosensitizing potential of ferulic acid in drug resistant KB Ch(R)8-5 cell lines. Ferulic acid treatment enhances paclitaxel mediated cell cycle arrest and upregulates paclitaxel-induced apoptotic signaling in KB resistant cells. Hence, it has been concluded that downregulation of ABCB1 and subsequent induction of paclitaxel-mediated cell cycle arrest and apoptotic signaling may be the cause for the chemosensitizing potential of ferulic acid in P-gp overexpressing cell lines. PMID:27262378

  8. MODULATION OF MDR-1 GENE IN HUMAN BREAST CANCER CELLS BY SODIUM BUTYRATE AND DMSO

    2001-01-01

    Objective: To analyze the regulation effect of MDR-1 gene inhuman breast cancer cell by the differentiating agents, sodium butyrate and dimethyl sulfoxide. Methods: 1. A sensitive assay, RT-PCR, was used to measure the mRNA level before and after the treatment of sodium butyrate, DMSO, using b -actin as control; 2. Evaluated the effect of sodium butyrate, DMSO on MDR-1 gene expression of human breast cancer at the protein level by immunoflow cytometry; 3. P-glycoprotein function was examined after accumulation of the fluorescent drug, Phodamine-123, by flow cytometry; 4. Chemosensitivity to doxorubicin was analyzed using the MTT assay. Results: Sodium butyrate and DMSO were found to increase the MDR characteristics on MDR-1 gene, MDR-1 expression levels, P-glycoprotein function and chemosensitivity to doxorubicin. Conclusion: sodium butyrate, DMSO can modulate the MDR-1 gene at gene level, protein level, protein function level and cell level.

  9. Evidence for altered ion transport in Saccharomyces cerevisiae overexpressing human MDR 1 protein.

    Fritz, F; Howard, E M; Hoffman, M M; Roepe, P D

    1999-03-30

    Recently [Hoffman, M. M., and Roepe, P. D. (1997) Biochemistry 36, 11153-11168] we presented evidence for a novel Na+- and Cl--dependent H+ transport process in LR73/hu MDR 1 CHO transfectants that likely explains pHi, volume, and membrane potential changes in eukaryotic cells overexpressing the hu MDR 1 protein. To further explore this process, we have overexpressed human MDR 1 protein in yeast strain 9.3 following a combination of approaches used previously [Kuchler, K., and Thorner, J. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 2302-2306; Ruetz, S., et al. (1993) Proc. Natl. Acad. Sci. U.S.A. 90, 11588-11592]. Thus, a truncated hu MDR 1 cDNA was cloned behind a tandem array of sterile 6 (Ste6) and alchohol dehydrogenase (Adh) promoters to create the yeast expression vector pFF1. Valinomycin resistance of intact cells and Western blot analysis with purified yeast plasma membranes confirmed the overexpression of full length, functional, and properly localized hu MDR 1 protein in independently isolated 9.3/pFF1 colonies. Interestingly, relative valinomycin resistance and growth of the 9.3/hu MDR 1 strains are found to strongly depend on the ionic composition of the growth medium. Atomic absorption reveals significant differences in intracellular K+ for 9.3/hu MDR 1 versus control yeast. Transport assays using [3H]tetraphenylphosphonium ([3H]TPP+) reveal perturbations in membrane potential for 9.3/hu MDR 1 yeast that are stimulated by KCl and alkaline pHex. ATPase activity of purified plasma membrane fractions from yeast strains and LR73/hu MDR 1 CHO transfectants constructed previously [Hoffman, M. M., et al. (1996) J. Gen. Physiol. 108, 295-313] was compared. MDR 1 ATPase activity exhibits a higher pH optimum and different salt dependencies, relative to yeast H+ ATPase. Inside-out plasma membrane vesicles (ISOV) fabricated from 9.3/hu MDR 1 and control strains were analyzed for formation of H+ gradients +/- verapamil. Similar pharmacologic profiles are found for

  10. Impacts of ABCB1 (G1199A) polymorphism on resistance, uptake, and efflux to steroid drugs.

    Peng, Rui; Zhang, Hong; Zhang, Ying; Wei, Dan-Yun

    2016-10-01

    1. P-glycoprotein (P-gp) substrates, including steroid drugs, involve in the inter-individual differences in resistant phenotype. This study was performed to evaluate whether G1199A polymorphism in ABCB1 gene can alter the sensitivity, accumulation, and transepithelial efflux to steroids in LLC-PK1 cells. 2. The stable recombinant LLC-PK1 cell lines transfected with ABCB1 1199G and ABCB1 1199A were used to assess the sensitivity, accumulation, and transepithelial permeability to steroids. 3. The cells transfected with 1199A allele displayed stronger resistance to aldosterone, dexamethasone, and cortisol (2.5-, 2.0-, and 1.6-fold, respectively) than cells overexpressing 1199G allele, while the two types of recombinant cells showed a similar resistance to corticosterone. The accumulation of aldosterone, dexamethasone, and cortisol in recombinant 1199A cells were significantly decreased when compared to 1199G cells (2.9-, 4.4-, and 3.9-fold, respectively). The net efflux ratios of P-gp-mediated aldosterone, dexamethasone, and cortisol in cells expressing 1199A allele were apparently greater than cells transfected with 1199G allele (3.3-, 3.5-, and 4.0-fold, respectively). 4. The impacts of ABCB1 (G1199A) single nucleotide polymorphism on the efflux of P-gp substrates presented as drug-specific. Overall, the transport ability of P-gp-dependent steroid drugs in recombinant model overexpressing variant 1199A allele is stronger in comparison to cells overexpressing wild-type 1199G allele. Therefore, the ABCB1 (G1199A) polymorphism may affect effective steroids concentration in target cells by regulating the drug transport and distribution. PMID:26822676

  11. Possible association of ABCB1:c.3435T>C polymorphism with high-density-lipoprotein-cholesterol response to statin treatment - a pilot study.

    Anna Sałacka

    2014-08-01

    Full Text Available The gene product ABCB1 (formerly MDR1 or P-glycoprotein is hypothesized to be involved in cholesterol cellular trafficking, redistribution and intestinal re-absorption. Carriers of the ABCB1:3435T allele have previously been associated with decreases in ABCB1 mRNA and protein concentrations and have been correlated with changes in serum lipid concentrations. The aim of this study was to investigate possible association between the ABCB1:3435T>C polymorphism and changes in lipids in patients following statin treatment. Outpatients (n=130 were examined: 43 men (33%, 87 women (67%: treated with atorvastatin or simvastatin (all patients with equivalent dose of 20 or 40 mg/d simvastatin. Blood was taken for ABCB1:3435T>C genotyping, and before and after statin treatment for lipid concentration determination (total cholesterol, high-density-lipoprotein-cholesterol (HDL-C, triglycerides. Change (Δ in lipid parameters, calculated as differences between measurements before and after treatment, were analyzed with multiple regression adjustments: gender, diabetes, age, body mass index, equivalent statin dose, length of treatment. Univariate and multivariate analyses showed significant differences in ΔHDL-C (univariate p=0.029; multivariate p=0.036 and %ΔHDL-C (univariate p=0.021; multivariate p=0.023 between patients with TT (-0.05 ± 0.13 g/l; -6.8% ± 20%; respectively and CC+CT genotypes (0.004 ± 0.15 g/l; 4.1 ± 26%; respectively. Reduction of HDL-C in homozygous ABCB1:3435TT patients suggests this genotype could be associated with a reduction in the benefits of statin treatment.

  12. The effect of combination therapy with doxorubicin and I-131 in multidrug resistance (MDR) gene expressing cancer cells by transduced shRNA for mdr1 mRNA and sodium Iodine symporter (NIS) genes

    Ahn, Sohn Joo; Lee, Yong Jin; Lee, You La; Lee, Sang Woo; Yoo, Jeong Soo; Ahn, Byeong Cheol; Lee, Jae Tae [School of Medicine, Kyungpook National University, Daegu (Korea, Republic of)

    2007-07-01

    Transduction of shMDR for mdr1 gene and NIS gene into MDR cancer cells expressing MDR can improve therapeutic effect of anticancer treatment. We have established stable cell lines expressing both shMDR and NIS gene using mammalian expression vector from human colon cancer cells having MDR characteristics. In this study, we have evaluated effects of combined therapy with doxorubicin and I-131 in xenograft model of MDR human colon cancer cells transduced with shMDR and NIS genes. We prepared adenoviruses containing shMDR (Ad-shMDR) or NIS (Ad-NIS) gene and finally established stable cell lines expressing both shMDR and NIS gene. Two days after transfection, inhibition of P-gp function by shMDR was assessed by a change of Tc-99m MIBI uptake, and functional activity of induced NIS expression was also assessed by a change of I-125 uptake. Doxorubicin and I-131 cytotoxicity was measured in Ad-shMDR transfected or non-transfected cell lines. Tc-99m MlBl and I-131 images was obtained effect in Ad-shMDR/NIS-cotransfected tumor xenograft. Dual therapy using doxorubicin and I-131 was measured effect in injected tumor xenograft by shMDR and NIS gene expressing stable cells. After transfection, uptake of Tc-99m MIBI and I-125 increased up to {approx}1.5-fold and approximately 25-fold compared to control. Ad-shMDR/NIS-cotransfected HCT15 cell showed enhanced cytotoxicity by doxorubicin and I-131 compared to control. Tc-99m MIBI and I-131 images demonstrated that in Ad-shMDR/NIS-cotransfected tumor xenograft were 2 and 10 times higher than that in non-intratumoral injected tumor xenograft. Therapy with I-131, or both doxorubicin and I-131 were revealed enhanced tumor regression than control group. Suppression of mdr1 gene expression and enhanced iodine uptake can be produced by shMDR and NIS gene transfection. Dual therapy with doxorubicin and radioiodine followed by transfection of shMDR/NIS gene can be effectively used in MDR expressing cancer cell.

  13. The putative P-gp inhibitor telmisartan does not affect the transcellular permeability and cellular uptake of the calcium channel antagonist verapamil in the P-glycoprotein expressing cell line MDCK II MDR1

    Saaby, Lasse; Tfelt-Hansen, Peer; Brodin, Birger

    2015-01-01

    Verapamil is used in high doses for the treatment of cluster headache. Verapamil has been described as a P-glycoprotein (P-gp, ABCB1) substrate. We wished to evaluate in vitro whether co administration of a P-gp inhibitor with verapamil could be a feasible strategy for increasing CNS uptake of...

  14. Establishment and characterization of an MDCK cell line stably-transfected with chicken Abcb1 encoding P-glycoprotein.

    Sun, Yong; Guo, Tingting; Guo, Dawei; Guo, Li; Chen, Li; Zhang, Yu; Wang, Liping

    2016-06-01

    Chicken P-glycoprotein (chP-gp), encoded by Abcb1, determines the bioavailability because of its effect on pharmacokinetics of various drugs. However, comprehensive studies on chP-gp are still limited. In this study, the chicken full-length cDNA was first successfully cloned and then stably expressed in MDCK cell line. The open reading frame of chicken Abcb1 consists of 3864 nucleotides, encoding for a 1287-amino acid protein. Sequence alignments analysis showed that chicken P-gp had high identities with the homologues of turkey (95%), human (72%), pig (72%), rat (71%) and cattle (68%). The efflux ratio of rhodamine123 (Rho123, a human P-gp substrate) in chAbcb1 transfected MDCK cells was significantly higher than that in the wild type MDCK cell (6.24 vs 1.64, P<0.05), suggesting a good transporting function of chicken P-gp overexpressed in the transfected cell. Importantly, MDCK-chAbcb1 cells, unlike Caco-2 cells, exhibited biphasic saturation kinetics in transporting Rho123. In conclusion, an MDCK cell line stably expressing chAbcb1 was successfully established, which could provide a new cell model to screen its substrates and inhibitors and study the drug-drug interaction medicated via chicken P-gp. PMID:27234533

  15. Structural and functional analysis of the mouse mdr1b gene promoter.

    Cohen, D; Piekarz, R L; Hsu, S I; DePinho, R A; Carrasco, N; Horwitz, S B

    1991-02-01

    The overproduction of P-glycoprotein, an integral membrane protein thought to function as a drug efflux pump, is the hallmark of the multidrug resistance phenotype. In murine multidrug resistant J774.2 cell lines, distinct mdr genes, mdr1a and mdr1b, encode unique P-glycoprotein isoforms. To examine the transcriptional regulation of the mdr1b gene, its promoter was isolated and characterized. The transcription initiation site was mapped by primer extension, and the 5'-flanking region was sequenced. Several potential regulatory elements were identified in this region. A transient expression vector was constructed by fusion of 540 base pairs of 5'-flanking sequence and part of the first untranslated exon to the chloramphenicol acetyltransferase (CAT) gene. When transfected into monkey kidney COS-1, rat pituitary GH3 or T47D human breast cells, the mdr1b 5'-flanking sequences were capable of driving CAT expression. Transient transfection studies using deletion subclones of the mdr1b-CAT construct were done to locate potential cis-acting sequences. The studies indicate the presence of cis-acting elements in the 5'-flanking region of the mdr1b gene. The implications of these findings for expression and regulation of the mdr1b gene are discussed. PMID:1671222

  16. Specificity of drug transport mediated by CaMDR1: a major facilitator of Candida albicans

    Avmeet Kohli; Vinita Gupta; Shankarling Krishnamurthy; Seyed E Hasnain; Rajendra Prasad

    2001-09-01

    CaMDR1 encodes a major facilitator superfamily (MFS) protein in Candida albicans whose expression has been linked to azole resistance and which is frequently encountered in this human pathogenic yeast. In this report we have overexpressed CaMdr1p in Sf9 insect cells and demonstrated for the first time that it can mediate methotrexate (MTX) and fluconazole (FLC) transport. MTX appeared to be a better substrate for CaMdr1p among these two tested drugs. Due to severe toxicity of these drugs to insect cells, further characterization of CaMdr1p as a drug transporter could not be done with this system. Therefore, as an alternative, CaMdr1p and Cdr1p, which is an ABC protein (ATP binding cassette) also involved in azole resistance in C. albicans, were independently expressed in a common hypersensitive host JG436 of Saccharomyces cerevisiae. This allowed a better comparison between the functionality of the two export pumps. We observed that while both FLC and MTX are effluxed by CaMdr1p, MTX appeared to be a poor substrate for Cdr1p. JG436 cells expressing Cdr1p thus conferred resistance to other antifungal drugs but remained hypersensitive to MTX. Since MTX is preferentially transported by CaMdr1p, it can be used for studying the function of this MFS protein.

  17. Dioscin enhances methotrexate absorption by down-regulating MDR1 in vitro and in vivo

    Wang, Lijuan, E-mail: jlwang1979@163.com [Department of Clinical Pharmacology, College of Pharmacy, Dalian Medical University, Dalian, Liaoning (China); Wang, Changyuan, E-mail: wangcyuan@163.com [Department of Clinical Pharmacology, College of Pharmacy, Dalian Medical University, Dalian, Liaoning (China); Provincial Key Laboratory for Pharmacokinetics and Transport, Liaoning, Dalian Medical University, Dalian, Liaoning (China); Peng, Jinyong, E-mail: jinyongpeng2005@163.com [Department of Clinical Pharmacology, College of Pharmacy, Dalian Medical University, Dalian, Liaoning (China); Provincial Key Laboratory for Pharmacokinetics and Transport, Liaoning, Dalian Medical University, Dalian, Liaoning (China); Liu, Qi, E-mail: llaqii@yahoo.com.cn [Department of Clinical Pharmacology, College of Pharmacy, Dalian Medical University, Dalian, Liaoning (China); Provincial Key Laboratory for Pharmacokinetics and Transport, Liaoning, Dalian Medical University, Dalian, Liaoning (China); Meng, Qiang, E-mail: mengq531@yahoo.cn [Department of Clinical Pharmacology, College of Pharmacy, Dalian Medical University, Dalian, Liaoning (China); Provincial Key Laboratory for Pharmacokinetics and Transport, Liaoning, Dalian Medical University, Dalian, Liaoning (China); Sun, Huijun, E-mail: sunhuijun@hotmail.com [Department of Clinical Pharmacology, College of Pharmacy, Dalian Medical University, Dalian, Liaoning (China); Provincial Key Laboratory for Pharmacokinetics and Transport, Liaoning, Dalian Medical University, Dalian, Liaoning (China); Huo, Xiaokui, E-mail: huoxiaokui@163.com [Department of Clinical Pharmacology, College of Pharmacy, Dalian Medical University, Dalian, Liaoning (China); Provincial Key Laboratory for Pharmacokinetics and Transport, Liaoning, Dalian Medical University, Dalian, Liaoning (China); and others

    2014-06-01

    The purpose of this study was to investigate the enhancing effect of dioscin on the absorption of methotrexate (MTX) and clarify the molecular mechanism involved in vivo and in vitro. Dioscin increased MTX chemosensitivity and transepithelial flux in the absorptive direction, significantly inhibiting multidrug resistance 1 (MDR1) mRNA and protein expression and MDR1 promoter and nuclear factor κ-B (NF-κB) activities in Caco-2 cells. Moreover, inhibitor κB-α (IκB-α) degradation was inhibited by dioscin. Dioscin enhanced the intracellular concentration of MTX by down-regulating MDR1 expression through a mechanism that involves NF-κB signaling pathway inhibition in Caco-2 cells. Dioscin strengthened MTX absorption by inhibiting MDR1 expression in rat intestine. In addition, even though MTX is absorbed into the enterocytes, there was no increase in toxicity observed, and that, in fact, decreased toxicity was seen. - Highlights: • Dioscin raised MTX concentration by inhibiting MDR1 in Caco-2 cells. • Dioscin suppresses MDR1 by inhibiting NF-κB signaling pathway in Caco-2 cells. • Dioscin can enhance MTX absorption via inhibiting MDR1 in vivo and in vitro. • Dioscin did not increase MTX-induced gastrointestinal mucosal toxicity.

  18. Dioscin enhances methotrexate absorption by down-regulating MDR1 in vitro and in vivo

    The purpose of this study was to investigate the enhancing effect of dioscin on the absorption of methotrexate (MTX) and clarify the molecular mechanism involved in vivo and in vitro. Dioscin increased MTX chemosensitivity and transepithelial flux in the absorptive direction, significantly inhibiting multidrug resistance 1 (MDR1) mRNA and protein expression and MDR1 promoter and nuclear factor κ-B (NF-κB) activities in Caco-2 cells. Moreover, inhibitor κB-α (IκB-α) degradation was inhibited by dioscin. Dioscin enhanced the intracellular concentration of MTX by down-regulating MDR1 expression through a mechanism that involves NF-κB signaling pathway inhibition in Caco-2 cells. Dioscin strengthened MTX absorption by inhibiting MDR1 expression in rat intestine. In addition, even though MTX is absorbed into the enterocytes, there was no increase in toxicity observed, and that, in fact, decreased toxicity was seen. - Highlights: • Dioscin raised MTX concentration by inhibiting MDR1 in Caco-2 cells. • Dioscin suppresses MDR1 by inhibiting NF-κB signaling pathway in Caco-2 cells. • Dioscin can enhance MTX absorption via inhibiting MDR1 in vivo and in vitro. • Dioscin did not increase MTX-induced gastrointestinal mucosal toxicity

  19. 多剤耐性遺伝子(MDR1)過剰発現肝細胞癌に対するelectrochemotherapyの有用性に関する基礎的検討

    西脇, 功

    2003-01-01

    The aim of this study was to investigate the role of electroporation in thetreatment of carcinoma expressing multidrug resistance gene 1 (MDR1). The cells stablyexpressing MDR1 gene (BNL/MDR1-Bulk) and the clone expressing the MDR1 gene atthe highest level (BNL/MDR1-Clone) were established by transducing human MDR1gene into the mouse hepatocellular carcinoma (HCC) cell line, BNLIME.7R.1. Theexpressions of P-glycoprotein on the cell surface of the established HCC cells,BNL/MDR1-Bulk and BNL/MD...

  20. Impact of ABCB1 1236C > T-2677G > T-3435C > T polymorphisms on the anti-proliferative activity of imatinib, nilotinib, dasatinib and ponatinib

    Dessilly, Géraldine; Panin, Nadtha; Elens, Laure; Haufroid, Vincent; Demoulin, Jean-Baptiste

    2016-01-01

    Overexpression of ABCB1 (also called P-glycoprotein) confers resistance to multiple anticancer drugs, including tyrosine kinase inhibitors (TKIs). Several ABCB1 single nucleotide polymorphisms affect the transporter activity. The most common ABCB1 variants are 1236C > T, 2677G > T, 3435C > T and have been associated with clinical response to imatinib in chronic myelogenous leukaemia (CML) in some studies. We evaluated the impact of these polymorphisms on the anti-proliferative effect and the intracellular accumulation of TKIs (imatinib, nilotinib, dasatinib and ponatinib) in transfected HEK293 and K562 cells. ABCB1 overexpression increased the resistance of cells to doxorubicin, vinblastine and TKIs. Imatinib anti-proliferative effect and accumulation were decreased to a larger extent in cells expressing the ABCB1 wild-type protein compared with the 1236T-2677T-3435T variant relatively to control cells. By contrast, ABCB1 polymorphisms influenced the activity of nilotinib, dasatinib and ponatinib to a much lesser extent. In conclusion, our data suggest that wild-type ABCB1 exports imatinib more efficiently than the 1236T-2677T-3435T variant protein, providing a molecular basis for the reported association between ABCB1 polymorphisms and the response to imatinib in CML. Our results also point to a weaker impact of ABCB1 polymorphisms on the activity of nilotinib, dasatinib and ponatinib. PMID:27405085

  1. Case-control association study of ABCB1 gene and major depressive disorder in a local Chinese Han population

    Xie WW

    2015-08-01

    Full Text Available Wei-Wei Xie,1,2* Lin Zhang,1* Ren-Rong Wu,1 Yan Yu,3 Jing-Ping Zhao,1 Le-Hua Li1 1Mental Health Institute of the Second Xiangya Hospital, National Technology Institute of Psychiatry, Key Laboratory of Psychiatry and Mental Health of Hunan Province, Central South University, Changsha, Hunan, 2Department of Psychiatry, Ningbo Kangning Hospital, Ningbo, 3People’s Hospital of Hunan Province, Changsha, People’s Republic of China *These authors contributed equally to this work Background: Human P-glycoprotein encoded by the ATP-binding cassette sub-family B member 1 (ABCB1 gene is expressed in the blood–brain barrier. ABCB1 protects the brain from many drugs and toxins such as glucocorticoids through the efflux pump. Recent evidence suggests that a specific allele of the ABCB1 gene confers susceptibility to major depressive disorder (MDD in the Japanese population. The aim of this study was to explore the association of ABCB1 gene polymorphisms with MDD in a local Chinese Han population.Methods: Two hundred and ninety-two MDD patients and 208 unrelated individuals were matched by age and sex and examined using a case-control design. Six single nucleotide polymorphisms (SNPs of the ABCB1 gene, including rs1045642, rs2032583, rs2032582, rs2235040, rs1128503, and rs2235015, were genotyped by ligase detection reaction and multiplex polymerase chain reaction. Linkage disequilibrium and haplotype analysis were investigated in the two study groups. Results: Significant protection for MDD individuals carrying the TG haplotype of rs1045642–rs2032582 was observed (odds ratio 0.470, 95% confidence interval 0.251–0.897, P=0.01.The rs2032582 (G2677T and rs1128503 (C1236T SNPs of ABCB1 showed nominal associations with MDD; the other four SNPs of the ABCB1 gene were not associated with MDD.Conclusion: Chinese individuals carrying the TG haplotype of rs1045642–rs2032582 had a nearly 53% lower risk of developing MDD. To the best of our

  2. Identification of a Cryptic Bacterial Promoter in Mouse (mdr1a P-Glycoprotein cDNA.

    Kristen M Pluchino

    Full Text Available The efflux transporter P-glycoprotein (P-gp is an important mediator of various pharmacokinetic parameters, being expressed at numerous physiological barriers and also in multidrug-resistant cancer cells. Molecular cloning of homologous cDNAs is an important tool for the characterization of functional differences in P-gp between species. However, plasmids containing mouse mdr1a cDNA display significant genetic instability during cloning in bacteria, indicating that mdr1a cDNA may be somehow toxic to bacteria, allowing only clones containing mutations that abrogate this toxicity to survive transformation. We demonstrate here the presence of a cryptic promoter in mouse mdr1a cDNA that causes mouse P-gp expression in bacteria. This expression may account for the observed toxicity of mdr1a DNA to bacteria. Sigma 70 binding site analysis and GFP reporter plasmids were used to identify sequences in the first 321 bps of mdr1a cDNA capable of initiating bacterial protein expression. An mdr1a M107L cDNA containing a single residue mutation at the proposed translational start site was shown to allow sub-cloning of mdr1a in E. coli while retaining transport properties similar to wild-type P-gp. This mutant mdr1a cDNA may prove useful for efficient cloning of mdr1a in E. coli.

  3. Modulation of human multidrug-resistance MDR-1 gene by natural curcuminoids

    Buddhasukh Duang

    2004-04-01

    Full Text Available Abstract Background Multidrug resistance (MDR is a phenomenon that is often associated with decreased intracellular drug accumulation in patient's tumor cells resulting from enhanced drug efflux. It is related to the overexpression of a membrane protein, P-glycoprotein (Pgp-170, thereby reducing drug cytotoxicity. A variety of studies have tried to find MDR modulators which increase drug accumulation in cancer cells. Methods In this study, natural curcuminoids, pure curcumin, demethoxycurcumin and bisdemethoxycurcumin, isolated from turmeric (Curcuma longa Linn, were compared for their potential ability to modulate the human MDR-1 gene expression in multidrug resistant human cervical carcinoma cell line, KB-V1 by Western blot analysis and RT-PCR. Results Western blot analysis and RT-PCR showed that all the three curcuminoids inhibited MDR-1 gene expression, and bisdemethoxycurcumin produced maximum effect. In additional studies we found that commercial grade curcuminoid (approximately 77% curcumin, 17% demethoxycurcumin and 3% bisdemthoxycurcumin decreased MDR-1 gene expression in a dose dependent manner and had about the same potent inhibitory effect on MDR-1 gene expression as our natural curcuminoid mixtures. Conclusion These results indicate that bisdemethoxycurcumin is the most active of the curcuminoids present in turmeric for modulation of MDR-1 gene. Treatment of drug resistant KB-V1 cells with curcumin increased their sensitivity to vinblastine, which was consistent with a decreased MDR-1 gene product, a P-glycoprotein, on the cell plasma membrane. Although many drugs that prevent the P-glycoprotein function have been reported, this report describes the inhibition of MDR-1 expression by a phytochemical. The modulation of MDR-1 expression may be an attractive target for new chemosensitizing agents.

  4. Modulation of human multidrug-resistance MDR-1 gene by natural curcuminoids

    Multidrug resistance (MDR) is a phenomenon that is often associated with decreased intracellular drug accumulation in patient's tumor cells resulting from enhanced drug efflux. It is related to the overexpression of a membrane protein, P-glycoprotein (Pgp-170), thereby reducing drug cytotoxicity. A variety of studies have tried to find MDR modulators which increase drug accumulation in cancer cells. In this study, natural curcuminoids, pure curcumin, demethoxycurcumin and bisdemethoxycurcumin, isolated from turmeric (Curcuma longa Linn), were compared for their potential ability to modulate the human MDR-1 gene expression in multidrug resistant human cervical carcinoma cell line, KB-V1 by Western blot analysis and RT-PCR. Western blot analysis and RT-PCR showed that all the three curcuminoids inhibited MDR-1 gene expression, and bisdemethoxycurcumin produced maximum effect. In additional studies we found that commercial grade curcuminoid (approximately 77% curcumin, 17% demethoxycurcumin and 3% bisdemthoxycurcumin) decreased MDR-1 gene expression in a dose dependent manner and had about the same potent inhibitory effect on MDR-1 gene expression as our natural curcuminoid mixtures. These results indicate that bisdemethoxycurcumin is the most active of the curcuminoids present in turmeric for modulation of MDR-1 gene. Treatment of drug resistant KB-V1 cells with curcumin increased their sensitivity to vinblastine, which was consistent with a decreased MDR-1 gene product, a P-glycoprotein, on the cell plasma membrane. Although many drugs that prevent the P-glycoprotein function have been reported, this report describes the inhibition of MDR-1 expression by a phytochemical. The modulation of MDR-1 expression may be an attractive target for new chemosensitizing agents

  5. Geographical Distribution of MDR1 Expression in Leishmania Isolates, from Greece and Cyprus, Measured by the Rhodamine-123 Efflux Potential of the Isolates, Using Flow Cytometry.

    Tsirigotakis, Nikolaos; Christodoulou, Vasiliki; Ntais, Pantelis; Mazeris, Apostolos; Koutala, Eleni; Messaritakis, Ippokratis; Antoniou, Maria

    2016-05-01

    Leishmaniasis, a neglected vector-borne disease caused by the protozoan parasite Leishmania, is encountered in 98 countries causing serious concerns to public health. The most alarming is the development of parasite drug resistance, a phenomenon increasingly encountered in the field rendering chemotherapy ineffective. Although resistance to drugs is a complex phenomenon, the rate of efflux of the fluorescent dye Rhodamine-123 from the parasite body, using flow cytometry, is an indication of the isolate's ability to efflux the drug, thus avoiding death. The rate of efflux measured 275 Leishmania strains, isolated from patients and dogs from Greece and Cyprus, was measured and mapped to study the geographical distribution of the multidrug resistance (MDR) gene expression as an indication of the drug resistance of the parasite. The map showed that out of the seven prefectures, where dogs presented high efflux rates, five also had patients with high efflux rates. In one, out of the 59 prefectures studied, the highest number of isolates with efflux slope α > 1, in both human and dog isolates, was found; a fact which may suggest that spread of drug resistance is taking place. The virulence of the Leishmania strains, assessed after infecting human macrophages of the THP-1 cell line, fluctuated from 1% to 59.3% with only 2.5% of the isolates showing infectivity > 50%. The most virulent strains were isolated from Attica and Crete. PMID:27001764

  6. Significance of MDR1 and multiple drug resistance in refractory human epileptic brain

    Dini Gabriele

    2004-10-01

    Full Text Available Abstract Background The multiple drug resistance protein (MDR1/P-glycoprotein is overexpressed in glia and blood-brain barrier (BBB endothelium in drug refractory human epileptic tissue. Since various antiepileptic drugs (AEDs can act as substrates for MDR1, the enhanced expression/function of this protein may increase their active extrusion from the brain, resulting in decreased responsiveness to AEDs. Methods Human drug resistant epileptic brain tissues were collected after surgical resection. Astrocyte cell cultures were established from these tissues, and commercially available normal human astrocytes were used as controls. Uptake of fluorescent doxorubicin and radioactive-labeled Phenytoin was measured in the two cell populations, and the effect of MDR1 blockers was evaluated. Frozen human epileptic brain tissue slices were double immunostained to locate MDR1 in neurons and glia. Other slices were exposed to toxic concentrations of Phenytoin to study cell viability in the presence or absence of a specific MDR1 blocker. Results MDR1 was overexpressed in blood vessels, astrocytes and neurons in human epileptic drug-resistant brain. In addition, MDR1-mediated cellular drug extrusion was increased in human 'epileptic' astrocytes compared to 'normal' ones. Concomitantly, cell viability in the presence of cytotoxic compounds was increased. Conclusions Overexpression of MDR1 in different cell types in drug-resistant epileptic human brain leads to functional alterations, not all of which are linked to drug pharmacokinetics. In particular, the modulation of glioneuronal MDR1 function in epileptic brain in the presence of toxic concentrations of xenobiotics may constitute a novel cytoprotective mechanism.

  7. The multidrug resistance 1 (MDR1) gene polymorphism G-rs3789243-A is not associated with disease susceptibility in Norwegian patients with colorectal adenoma and colorectal cancer; a case control study

    Andersen, V.; Agerstjerne, L.; Jensen, D.;

    2009-01-01

    Background: Smoking, dietary factors, and alcohol consumption are known life style factors contributing to gastrointestinal carcinogenesis. Genetic variations in carcinogen handling may affect cancer risk. The multidrug resistance 1(MDR1/ABCB1) gene encodes the transport protein P-glycoprotein (a...... inflammation, and may thereby affect the risk of malignity. Hence, genetic variations that modify the function of P-glycoprotein may be associated with the risk of colorectal cancer (CRC). We have previously found an association between the MDR1 intron 3 G-rs3789243-A polymorphism and the risk of CRC in a...... Danish study population. The aim of this study was to investigate if this MDR1 polymorphism was associated with risk of colorectal adenoma (CA) and CRC in the Norwegian population. Methods: Using a case-control design, the association between the MDR1 intron 3 G-rs3789243-A polymorphism and the risk of...

  8. Polymorphisms of the ABCB1 gene in the pakistani population

    Objective: To investigate the frequency of the single nucleotide polymorphism C1236Tin exon 12 of the ABCB1 gene in Pakistani population and to compare it with published data on Asian and Caucasian populations. Study Design: Across-sectional observational study. Place and Duration of Study: Combined Military Hospital, Rawalpindi and Institute of Biomedical and Genetic Engineering (IBGE), Islamabad, from August 2012 to May 2013. Methodology: C1236T polymorphism was investigated in 426 Pakistani subjects. The frequency was compared with the published data on other Asian and Caucasian populations. Results: The frequencies of ABCB1 C1236T were 16.4% for CC, 44.1% for CT and 39.4% for TT. Pakistanis differed significantly from all the European populations compared in the distribution of the TT genotype of C1236TABCB1 (p < 0.05). The Pakistani population also differed significantly from some of the European populations in the distribution of CC and CT genotype (p < 0.05). Conclusion: There was significant difference in the genotype frequency of the ABCB1 gene compared to other populations. This study has provided a framework for future pharmacogenetic and pharmacokinetic studies on this polymorphic variant of ABCB1 gene in the Pakistani population. (author)

  9. Genome-wide association data suggest ABCB1 and immune-related gene sets may be involved in adult antisocial behavior.

    Salvatore, J E; Edwards, A C; McClintick, J N; Bigdeli, T B; Adkins, A; Aliev, F; Edenberg, H J; Foroud, T; Hesselbrock, V; Kramer, J; Nurnberger, J I; Schuckit, M; Tischfield, J A; Xuei, X; Dick, D M

    2015-01-01

    Adult antisocial behavior (AAB) is moderately heritable, relatively common and has adverse consequences for individuals and society. We examined the molecular genetic basis of AAB in 1379 participants from a case-control study in which the cases met criteria for alcohol dependence. We also examined whether genes of interest were expressed in human brain. AAB was measured using a count of the number of Antisocial Personality Disorder criteria endorsed under criterion A from the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV). Participants were genotyped on the Illumina Human 1M BeadChip. In total, all single-nucleotide polymorphisms (SNPs) accounted for 25% of the variance in AAB, although this estimate was not significant (P=0.09). Enrichment tests indicated that more significantly associated genes were over-represented in seven gene sets, and most were immune related. Our most highly associated SNP (rs4728702, P=5.77 × 10(-7)) was located in the protein-coding adenosine triphosphate-binding cassette, sub-family B (MDR/TAP), member 1 (ABCB1). In a gene-based test, ABCB1 was genome-wide significant (q=0.03). Expression analyses indicated that ABCB1 was robustly expressed in the brain. ABCB1 has been implicated in substance use, and in post hoc tests we found that variation in ABCB1 was associated with DSM-IV alcohol and cocaine dependence criterion counts. These results suggest that ABCB1 may confer risk across externalizing behaviors, and are consistent with previous suggestions that immune pathways are associated with externalizing behaviors. The results should be tempered by the fact that we did not replicate the associations for ABCB1 or the gene sets in a less-affected independent sample. PMID:25918995

  10. The involvement of a LINE-1 element in a DNA rearrangement upstream of the mdr1a gene in a taxol multidrug-resistant murine cell line.

    Cohen, D; Higman, S M; Hsu, S I; Horwitz, S B

    1992-10-01

    Two closely related but functionally distinct P-glycoprotein isoforms are encoded by the murine multidrug-resistance genes mdr1a and mdr1b. In a series of independently selected multidrug-resistant (MDR) J774.2 cell lines, mdr gene amplification and/or overexpression and overproduction of either the mdr1a or mdr1b products, or both gene products, correlates with the MDR phenotype. To investigate the possibility that mutations in the promoter regions of the mdr1a or mdr1b genes could influence their differential expression, mdr promoter-specific probes were used to detect and map potential structural alterations. An unusual structural rearrangement was found in the 5'-region of the amplified mdr1a allele in J7.T1, a cell line selected with taxol. To characterize this rearrangement, the regulatory regions of the mdr1a and mdr1b genes were analyzed. Whereas no gross structural alterations were detected by Southern blot hybridization using the mdr1b promoter probe, a novel amplified EcoRI fragment was detected by the mdr1a promoter probe. To determine the precise nature of this mutation, an mdr1a 5'-genomic clone was isolated from J7.T1 cells. Sequence analysis revealed an unusual DNA rearrangement consisting of the mdr1b gene, from its fourth intron toward its 3'-end, upstream of an intact mdr1a promoter on the amplified allele. We propose that this event occurred by an unequal sister chromatid exchange that was mediated by LINE-1 repetitive elements. PMID:1356977

  11. MDR-1 and MRP2 gene polymorphisms in Mexican epileptic pediatric patients with complex partial seizures.

    David eEscalante-Santiago

    2014-10-01

    Full Text Available Although the Pgp efflux transport protein is overexpressed in resected tissue of patients with epilepsy, the presence of polymorphisms in MDR1 / ABCB1 and MRP2 / ABCC2 in patients with antiepileptic-drugs resistant epilepsy is controversial. The aim of this study was to perform an exploratory study to identify nucleotide changes and search new and reported mutations in patients with antiepileptic-drugs resistant epilepsy (ADR and patients with good response to anti-epileptic drugs (CTR in a rigorously selected population. We analyzed 22 samples from drug-resistant patients with epilepsy and 7 samples from patients with good response to anti-epileptic drugs. Genomic DNA was obtained from leukocytes. Eleven exons in both genes were genotyped. The concentration of drugs in saliva and plasma was determined. The concentration of valproic acid in saliva was lower in ADR than in CRT. In ABCB1, five reported SNPs and five unreported nucleotide changes were identified; rs2229109 (GA and rs2032582 (AT and AG were found only in the ADR. Of six SNPs associated with the ABCC2 that were found in the study population, rs3740066 (TT and 66744T>A (TG were found only in the ADR. The strongest risk factor in the ABCB1 gene was identified as the TA genotype of rs2032582, whereas for the ABCC2 gene the strongest risk factor was the T allele of rs3740066. The screening of SNPs in ACBC1 and ABCC2 indicates that the Mexican patients with epilepsy in this study display frequently reported ABCC1 polymorphisms; however, in the study subjects with a higher risk factor for drug resistance, new nucleotide changes were found in the ABCC2 gene. Thus, the population of Mexican patients with AED-resistant epilepsy used in this study exhibits genetic variability with respect to those reported in other study populations; however, it is necessary to explore this polymorphism in a larger population of patients with AED-resistant epilepsy.

  12. Targeting MDR1-P-glycoprotein (MDR1-Pgp) in immunochemotherapy of acute myeloid leukemia (AML)

    Maurizio Cianfriglia

    2013-01-01

    BACKGROUND: Monoclonal antibodies represent the fastest growing sector of pharmaceutical biotechnology and a number of antibody-based biopharmaceuticals have been approved for cancer treatment. However, in many cases the antibodies used for the treatment of tumors offer only a modest survival benefit to cancer patients. AIMS: In the present review-article we intend to analyze: i) the curative regimen gemtuzumab ozogamicin (GO) -mediate characterized by the absence of cytotoxic drugs MDR1-Pgp ...

  13. Genomewide analysis of ABCBs with a focus on ABCB1 and ABCB19 in Malus domestica

    Juan Juan Ma; Mingyu Han

    2016-03-01

    The B subfamily of ATP-binding cassette (ABC) proteins (ABCB) plays a vital role in auxin efflux. However, no systematic study has been done in apple. In this study, we performed genomewide identification and expression analyses of the ABCB family in Malus domestica for the first time. We identified a total of 25 apple ABCBs that were divided into three clusters based on the phylogenetic analysis. Most ABCBs within the same cluster demonstrated a similar exon–intron organization. Additionally, the digital expression profiles of ABCB genes shed light on their functional divergence. ABCB1 and ABCB19 are two well-studied auxin efflux carrier genes, and we found that their expression levels are higher in young shoots of M106 than in young shoots of M9. Since young shoots are the main source of auxin synthesis and auxin efflux involves in tree height control. This suggests that ABCB1 and ABCB19 may also take a part in the auxin efflux and tree height control in apple.

  14. Loperamide, an FDA-Approved Antidiarrhea Drug, Effectively Reverses the Resistance of Multidrug Resistant MCF-7/MDR1 Human Breast Cancer Cells to Doxorubicin-Induced Cytotoxicity

    Zhou, Yanfei; Sridhar, Rajagopalan; Shan, Liang; Sha, Wei; Gu, Xinbin; Sukumar, Saraswati

    2011-01-01

    Loperamide is an FDA-approved antidiarrhea drug which acts on the μ-opioid receptors in the mesenteric plexus of large intestine and exhibits limited side effects. We hypothesized that loperamide might reverse the multidrug resistance (MDR) of human cancer cells to chemotherapeutic agents. MCF-7/MDR1 cells express high level of MDR1 and are resistant to doxorubicin. We found that loperamide significantly enhanced the cytotoxicity of doxorubicin to MCF-7/MDR1 cells in a dose-dependent manner. ...

  15. Evaluation of immunoexpression and MDR1 promoter methylation levels in prostatic tissue samples

    Moura, Inês; Costa, Vera L.; Pais, Irene; Ribeiro, Franclim R.; Henrique, Rui; Jerónimo, Carmen

    2008-01-01

    Os objectivos deste estudo foram: (1) Determinar os níveis de metilação do promotor do MDR1 em tecido prostático com adenocarcinoma (CaP), neoplasia intraepitelial prostática de alto grau (HGPIN), hiperplasia benigna (BPH) e tecido morfologicamente normal (MNP). (2) Correlacionar os níveis de metilação com a imunoexpressão da gp-P. Os nossos resultados demonstram que a hipermetilação do MDR1 constitui um mecanismo eficaz de regulação da sua expressão. Estudos futuros permitirão av...

  16. Identification of a putatively multixenobiotic resistance related Abcb1 transporter in amphipod species endemic to the highly pristine Lake Baikal.

    Pavlichenko, Vasiliy V; Protopopova, Marina V; Timofeyev, Maxim; Luckenbach, Till

    2015-04-01

    The fauna of Lake Baikal in Eastern Siberia, the largest freshwater body on Earth, is characterized by high degrees of biodiversity and endemism. Amphipods, a prominent taxon within the indigenous fauna, occur in an exceptionally high number of endemic species. Considering the specific water chemistry of Lake Baikal with extremely low levels of potentially toxic natural organic compounds, it seems conceivable that certain adaptions to adverse environmental factors are missing in endemic species, such as cellular defense mechanisms mitigating toxic effects of chemicals. The degree to which the endemic fauna is affected by the recently occurring anthropogenic water pollution of Lake Baikal may depend on the existence of such cellular defense mechanisms in those species. We here show that endemic amphipods express transcripts for Abcb1, a major component of the cellular multixenobiotic resistance (MXR) defense against toxic chemicals. Based on a partial abcb1 cDNA sequence from Gammarus lacustris, an amphipod species common across Northern Eurasia but only rarely found in Lake Baikal, respective homologous sequences were cloned from five amphipods endemic to Lake Baikal, Eulimnogammarus verrucosus, E. vittatus, E. cyaneus, E. marituji, and Gmelinoides fasciatus, confirming that abcb1 is transcribed in those species. The effects of thermal (25 °C) and chemical stress (1-2 mg L(-1) phenanthrene) in short-term exposures (up to 24 h) on transcript levels of abcb1 and heat shock protein 70 (hsp70), used as a proxy for cellular stress in the experiments, were exemplarily examined in E. verrucosus, E. cyaneus, and Gammarus lacustris. Whereas increases of abcb1 transcripts upon treatments occurred only in the Baikalian species E. verrucosus and E. cyaneus but not in Gammarus lacustris, changes of hsp70 transcript levels were seen in all three species. At least for species endemic to Lake Baikal, the data thus indicate that regulation of the identified amphipod abcb1 is

  17. Quantifizierung der ABCB1-mRNA in Lymphozytensubpopulationen

    Wolbergs, Daniel

    2015-01-01

    P-Glycoprotein (P-Gp) is a membrane-bound protein, which acts as an efflux-pump and reduces the intracellular concentration of its substrates. Its physiological function is the protection of the cell from toxic substances as well as the elimination of endogenous metabolic wastes. P-Gp plays an important role in cell-mediated immunity, in multi-drug resistance and in the phamacokinetics of numerous therapeutic agents. In humans P-Gp is encoded by the ABCB1-gene. A number of genetic polymorphis...

  18. Reversal of multi-drug resistance by pSUPER-shRNA-mdr1 in vivo and in vitro

    Guang-Dong Pan; Jian-Qing Yang; Lv-Nan Yan; Guang-Ping Chu; Qiang Liu; Yi Xiao; Lin Yuan

    2009-01-01

    AIM: To explore the possibility of reversing multi-drug resistance (MDR) to HepG2/mdr1 in vitro and in vivo with RNA interference (RNAi).METHODS: HepG2/mdr1 was obtained by cloning the whole gene mdr1 into HepG2 cells. shRNA targeting sequence was designed to be homologous to the P-gp encoding MDR1 mRNA consensus sequence. pSUPERshRNA/mdr1 was constructed using the enzymedigested technique. HepG2/mdr1 cells were transfected with vectors of pSUPER-shRNA/mdr1 to measure their efficacy by real-time PCR for mdr1 mRNA, flow cytometry (FCM) for P-gp expression, and Rhodamine efflux, MTT method for HepG2/mdr1 function,respectively. In vivo, mice tumors were treated by injecting pSUPER-shRNA/mdr1 in situ and into intraabdominal cavity. Tumors were collected to create cell suspension and cryosections after chemothearpy with adiramycin and mytomycin.The cell suspension was incubated in RPMI-1640 supplemented with G418 to screen stable cells for appreciating the reversal of MDR.Cryosections were treated with immunohistochemistry technique to show the effectiveness of transfection and the expression of P-gp.RESULTS: pSUPER-shRNA/mdr1 was successfully constructed, which was confirmed by sequencing.The MDR phenotype of HepG2/mdr1 was decreased significantly in vitro transfection. HepG2/mdr1 showing its MDR was reversed notably in P-gp expression (11.0% vs 98.2%, P < 0.01). Real-time PCR showed that mRNA/mdr1 was lower in test groups than in control groups (18.73 ± 1.33 vs 68.03 ± 2.21, P < 0.001).Compared with HepG2, the sensitivity of HepG2/mdr1 and HepG2/mdr1-dsRNA cells to ADM was decreased by 1.64 times and 15.6 times, respectively.The accumulation of DNR in positive groups was decreased by 1.64 times and 15.6 times,respectively.The accumulation of DNR in positive groups was decreased evidently. In vivo, the p-gp expression in positive groups was significantly lower than that in control groups (65.1% vs 94.1%, P < 0.05). The tumor suppressing rate in test groups was 57

  19. Involvement of V-Ets erythroblastosis virus E26 oncogene homolog 2 in regulation of transcription activity of MDR1 gene.

    Wang, Jian; Zeng, Xiaoqing; Luo, Tiancheng; Jin, Wei; Chen, Shiyao

    2012-09-01

    Over-expression of MDR1 confers multidrug resistance (MDR) in cancers and remains a major cause for the failure of chemotherapy. In the present study, we found that V-Ets erythroblastosis virus E26 oncogene homolog 2 (ETS2) could activate MDR1 transcription and P-glycoprotein (P-gp) expression in SGC7901 cells. Knockdown of ETS2 attenuated MDR1 transcription and P-gp expression, and increased the sensitivity of MDR cancer cells to cytotoxic drugs that were transported by P-gp in SGC7901/VCR cells. ETS2 could bind to the ETS2 sites on the MDR1 promoter and activate its transcription. The regulation of MDR1 expression by ETS2 may provide potential ways to overcome MDR in cancer treatment. PMID:22819965

  20. Targeting MDR1-P-glycoprotein (MDR1-Pgp in immunochemotherapy of acute myeloid leukemia (AML

    Maurizio Cianfriglia

    2013-06-01

    Full Text Available BACKGROUND: Monoclonal antibodies represent the fastest growing sector of pharmaceutical biotechnology and a number of antibody-based biopharmaceuticals have been approved for cancer treatment. However, in many cases the antibodies used for the treatment of tumors offer only a modest survival benefit to cancer patients. AIMS: In the present review-article we intend to analyze: i the curative regimen gemtuzumab ozogamicin (GO -mediate characterized by the absence of cytotoxic drugs MDR1-Pgp substrates to overcome the mechanism of action of this multidrug transporter, ii the safety and efficacy of MDR reversing strategy in AML outcome and, iii chemical and biological MDR modulators playing a dual relevant medical role as a therapeutic and MDR reversing agents but not yet entered in the clinical setting of AML. Since the similar multidrug transporter protein MDR1-Pgp and its down modulation factors may affect safety and efficacy of already generated antibody drug conjugates (ADCs a comprehensive overview of the most clinically representative immunoconjugates is reported. DISCUSSION: ADCs represent one of the most promising strategies to enhance the antitumor activity of antibodies. ADCs comprise an antibody (or an antibody fragment conjugated to a cytotoxic drug via a chemical linker. The therapeutic concept of ADCs is to use an antibody as a vehicle to selectively delivering a cytotoxic drug specifically to a tumor cell, in most cases by means of binding to target cell surface antigen. As a consequence, ADCs have significant potential for enhancing the antitumor activity of "naked" antibodies and reducing the systemic toxicity of the conjugated drugs.

  1. Effect of multidrug resistance gene-1(mdr1) overexpression on in-vitro uptake of 99mTc-sestaMIBI in murine L1210 leukemia cells

    To determine whether 99mTc-MIBI is recognized by the multidrug resistant P-glycoprotein (Pgp), we have measured quantitatively 99mTc-MIBI uptake in cancer cells. The effects of various Pgp reversing agents on cellular 99mTc-MIBI uptake were also investigated in the presence of multidrug resistance gene-1 (mdr 1 gene) overexpression. We measured percentage uptake of 99mTc-MIBI at different incubation temperatures both in mdr1 positive and negative cells. The effects of verapamil, cyclosporin, and dipyridamole on cellular uptake of 99mTc-MIBI were also evaluated with or without overexpression of mdr1 gene in cultured murine leukemia L1210 cells. The mdr1 gene expressing cell lines were effectively induced in in vitro with continuous application of low-dose adriamycin or vincristine. Cellular uptake of 99mTc-MIBI was higher in mdr1 negative L1210 cells than those of mdr1 positive cells, and higher when incubated in 37 .deg. C than 4 .deg. C. In the presence of verapamil, cyclosporin or dipyridamole, 99mTc-MIBI uptake was increased upto 604% in mdr1 positive cells. Cellular uptake of 99mTc-MIBI is lower in leukemia cells over-expressing mdr1 gene, and MDR-reversing agents increase cellular uptake. These results suggest the 99mTc-MIBI can be used for characterizing Pgp expression and developing MDR-reversing agents in vitro

  2. MDR1 siRNA loaded hyaluronic acid-based CD44 targeted nanoparticle systems circumvent paclitaxel resistance in ovarian cancer

    Yang, Xiaoqian; Lyer, Arun K.; Singh, Amit; Choy, Edwin; Hornicek, Francis J.; Amiji, Mansoor M.; Duan, Zhenfeng

    2015-02-01

    Development of multidrug resistance (MDR) is an almost universal phenomenon in patients with ovarian cancer, and this severely limits the ultimate success of chemotherapy in the clinic. Overexpression of the MDR1 gene and corresponding P-glycoprotein (Pgp) is one of the best known MDR mechanisms. MDR1 siRNA based strategies were proposed to circumvent MDR, however, systemic, safe, and effective targeted delivery is still a major challenge. Cluster of differentiation 44 (CD44) targeted hyaluronic acid (HA) based nanoparticle has been shown to successfully deliver chemotherapy agents or siRNAs into tumor cells. The goal of this study is to evaluate the ability of HA-PEI/HA-PEG to deliver MDR1 siRNA and the efficacy of the combination of HA-PEI/HA-PEG/MDR1 siRNA with paclitaxel to suppress growth of ovarian cancer. We observed that HA-PEI/HA-PEG nanoparticles can efficiently deliver MDR1 siRNA into MDR ovarian cancer cells, resulting in down-regulation of MDR1 and Pgp expression. Administration of HA-PEI/HA-PEG/MDR1 siRNA nanoparticles followed by paclitaxel treatment induced a significant inhibitory effect on the tumor growth, decreased Pgp expression and increased apoptosis in MDR ovarian cancer mice model. Our findings suggest that CD44 targeted HA-PEI/HA-PEG/MDR1 siRNA nanoparticles can serve as a therapeutic tool with great potentials to circumvent MDR in ovarian cancer.

  3. Prognostic significance of multidrug-resistance protein (MDR-1) in renal clear cell carcinomas: A five year follow-up analysis

    A large number of renal cancer patients shows poor or partial response to chemotherapy and the mechanisms have not been still understood. Multi-drug resistance is the principal mechanism by which many cancers develop resistance to chemotherapic drugs. The role of the multi-drug resistant transporter (MDR-1/P-glycoprotein), the gene product of MDR-1, and that one of the so-called multi-drug resistance associated protein (MRP), two energy-dependent efflux pumps, are commonly known to confer drug resistance. We studied MDR-1 expression in selected cases of renal cell carcinoma (RCC), clear cell type, with long-term follow-up, in order to establish its prognostic role and its possible contribution in the choice of post-surgical therapy. MDR-1 has been studied by standard LSAB-HRP immunohistochemical technique, in paraffin embedded RCC samples. Protein expression has been compared to clinical and histopathological data and to disease specific survival of RCC patients, by Kaplan-Meier curve and Cox multivariate regression analyses. Two groups of RCCs were obtained by esteeming MDR-1 expression and disease specific survival (obtained with Kaplan-Meier curve and Cox multivariate regression analyses): the first one presents low or absent MDR-1 expression and good survival; the second one is characterized by high MDR-1 expression and significant poor outcome (p < 0.05). Afterwards, we have found disease specific survival, adjusted for stages and independent of therapy: this difference of survival rates was statistically significant (p < 0.05). Stage adjusted disease specific survival rate, according to MDR-1 expression and therapy in patients affected by RCC in early stage (stage I), has revealed that the group of patients with high MDR-1 expression and without adjuvant therapy showed poor survival (p < 0.05). Cox multivariate regression analysis has confirmed that, in our cohort of RCC (clear cell type) patients, the strong association between MDR-1 and worse outcome is

  4. Analysis of mdr1-1Δ mutation of MDR1 gene in the “Cimarron Uruguayo” dog

    Rosa Gagliardi B.

    2013-08-01

    Full Text Available Objective. The aim of this paper is to analyze the frequency of the mdr1-1D mutation of the MDR1 gene in a dog sample of the Uruguayan Cimarron breed with the objective of increasing the knowledge of this breed’s genome. Materials and methods. Thirty-six animals of this breed were analyzed. The MDR1 gene region, which includes the location where the mutation would be present, was amplified by PCR. Results. The mutation was not detected in any of the analyzed Uruguayan Cimarron. Conclusions. The lack of described ivermectin intoxication cases in veterinary clinic in this breed is explained by the lack of the mutation object of this study. The sequence studied in Cimarron dogs is kept compared to other breeds, except Collies and related breeds (Border Collie, Bearded Collie, Old English sheepdog.

  5. Application of SPET using technetium-99m sestamibi in brain tumours and comparison with expression of the MDR-1 gene: is it possible to predict the response to chemotherapy in patients with gliomas by means of 99mTc-sestamibi SPET?

    In this study, MIBI SPET was compared with thallium-201 (Tl) SPET using magnetic resonance imaging as a guide in 16 patients with untreated brain tumours (ten glioblastomas (GBs)), two anaplastic astrocytomas (AAs), two low-grade gliomas (LGASs) and two metastatic brain tumours and in four patients who had received treatment for with brain tumours (two GBs, two AAs). In addition, we investigated the expression of the MDR-1 gene and its product Pgp inn the same patients, and compared the results with MIBI SPET findings. MIBI, as well as Tl, was highly accumulated and retained in the enhanced region of malignant gliomas. In addition, MIBI SPET yielded sharp and well-contrasted images, and the margin of the tumour was more clearly defined than with Tl SPET due to a good signal-to-noise ratio. Follow-up MIBI SPET in patients who had received therapy showed marked uptake in a patient with malignant transformation, who deteriorated clinically. Patients with no uptake on MIBI SPET showed no sign of recurrence. Semiquantitative analysis of untreated patients showed a relationship between the early uptake index and the degree of malignancy. The retention index (RI, ratio of delayed to early UI) of MIBI was significantly lower than that of Tl in metastatic brain tumours (P<0.05), but not in malignant gliomas. Histological and biological investigation of gliomas showed that the MDR-1 gene and its product Pgp were expressed only in normal endothelial cells and not in tumour cells or proliferating enen550601l cells; Pgp tended to decrease as the degree of malignancy rose. Hence, the presence of Pgp and the grade of malignancy were inversely related in gliomas. By contrast, immunohistochemical study showed strong accumulation of Pgp in metastatic brain tumour cells. (orig./MG) (orig.)

  6. Wnt/β-catenin pathway regulates ABCB1 transcription in chronic myeloid leukemia

    Corrêa Stephany

    2012-07-01

    Full Text Available Abstract Background The advanced phases of chronic myeloid leukemia (CML are known to be more resistant to therapy. This resistance has been associated with the overexpression of ABCB1, which gives rise to the multidrug resistance (MDR phenomenon. MDR is characterized by resistance to nonrelated drugs, and P-glycoprotein (encoded by ABCB1 has been implicated as the major cause of its emergence. Wnt signaling has been demonstrated to be important in several aspects of CML. Recently, Wnt signaling was linked to ABCB1 regulation through its canonical pathway, which is mediated by β-catenin, in other types of cancer. In this study, we investigated the involvement of the Wnt/β-catenin pathway in the regulation of ABCB1 transcription in CML, as the basal promoter of ABCB1 has several β-catenin binding sites. β-catenin is the mediator of canonical Wnt signaling, which is important for CML progression. Methods In this work we used the K562 cell line and its derived MDR-resistant cell line Lucena (K562/VCR as CML study models. Real time PCR (RT-qPCR, electrophoretic mobility shift assay (EMSA, chromatin immunoprecipitation (ChIP, flow cytometry (FACS, western blot, immunofluorescence, RNA knockdown (siRNA and Luciferase reporter approaches were used. Results β-catenin was present in the protein complex on the basal promoter of ABCB1 in both cell lines in vitro, but its binding was more pronounced in the resistant cell line in vivo. Lucena cells also exhibited higher β-catenin levels compared to its parental cell line. Wnt1 and β-catenin depletion and overexpression of nuclear β-catenin, together with TCF binding sites activation demonstrated that ABCB1 is positively regulated by the canonical pathway of Wnt signaling. Conclusions These results suggest, for the first time, that the Wnt/β-catenin pathway regulates ABCB1 in CML.

  7. Epigenetic modulation of the drug resistance genes MGMT, ABCB1 and ABCG2 in glioblastoma multiforme

    Oberstadt, Moritz C.; Bien-Möller, Sandra; Weitmann, Kerstin; Herzog, Susann; Hentschel, Katharina; Rimmbach, Christian; Vogelgesang, Silke; Balz, Ellen; Fink, Matthias; Michael, Heike; Zeden, Jan-Philip; Bruckmüller, Henrike; Werk, Anneke N.; Cascorbi, Ingolf; Hoffmann, Wolfgang

    2013-01-01

    Background Resistance of the highly aggressive glioblastoma multiforme (GBM) to drug therapy is a major clinical problem resulting in a poor patient’s prognosis. Beside promoter methylation of the O 6 -methylguanine-DNA-methyltransferase (MGMT) gene the efflux transporters ABCB1 and ABCG2 have been suggested as pivotal factors contributing to drug resistance, but the methylation of ABCB1 and ABCG2 has not been assessed before in GBM. Methods Therefore, we evaluated the proportion and pr...

  8. Wnt/β-catenin pathway regulates ABCB1 transcription in chronic myeloid leukemia

    The advanced phases of chronic myeloid leukemia (CML) are known to be more resistant to therapy. This resistance has been associated with the overexpression of ABCB1, which gives rise to the multidrug resistance (MDR) phenomenon. MDR is characterized by resistance to nonrelated drugs, and P-glycoprotein (encoded by ABCB1) has been implicated as the major cause of its emergence. Wnt signaling has been demonstrated to be important in several aspects of CML. Recently, Wnt signaling was linked to ABCB1 regulation through its canonical pathway, which is mediated by β-catenin, in other types of cancer. In this study, we investigated the involvement of the Wnt/β-catenin pathway in the regulation of ABCB1 transcription in CML, as the basal promoter of ABCB1 has several β-catenin binding sites. β-catenin is the mediator of canonical Wnt signaling, which is important for CML progression. In this work we used the K562 cell line and its derived MDR-resistant cell line Lucena (K562/VCR) as CML study models. Real time PCR (RT-qPCR), electrophoretic mobility shift assay (EMSA), chromatin immunoprecipitation (ChIP), flow cytometry (FACS), western blot, immunofluorescence, RNA knockdown (siRNA) and Luciferase reporter approaches were used. β-catenin was present in the protein complex on the basal promoter of ABCB1 in both cell lines in vitro, but its binding was more pronounced in the resistant cell line in vivo. Lucena cells also exhibited higher β-catenin levels compared to its parental cell line. Wnt1 and β-catenin depletion and overexpression of nuclear β-catenin, together with TCF binding sites activation demonstrated that ABCB1 is positively regulated by the canonical pathway of Wnt signaling. These results suggest, for the first time, that the Wnt/β-catenin pathway regulates ABCB1 in CML

  9. The roles of variants in human multidrug resistance (MDR1 gene and their haplotypes on antiepileptic drugs response: a meta-analysis of 57 studies.

    Hui Li

    Full Text Available Previous studies reported the associations between the ATP-binding cassette sub-family B member 1 (ABCB1, also known as MDR1 polymorphisms and their haplotypes with risk of response to antiepileptic drugs in epilepsy, however, the results were inconclusive.The Pubmed, Embase, Web of Science, CNKI and Chinese Biomedicine databases were searched up to July 15, 2014. Pooled odds ratios (ORs and 95% confidence intervals (CIs were calculated using a fixed-effects or random-effects model based on heterogeneity tests. Meta-regression and Galbraith plot analysis were carried out to explore the possible heterogeneity.A total of 57 studies involving 12407 patients (6083 drug-resistant and 6324 drug-responsive patients with epilepsy were included in the pooled-analysis. For all three polymorphisms (C3435T, G2677T/A, and C1236T, we observed a wide spectrum of minor allele frequencies across different ethnicities. A significantly decreased risk of AEDs resistance was observed in Caucasian patients with T allele of C3435T variant, which was still significant after adjusted by multiple testing corrections (T vs C: OR=0.83, 95%CI=0.71-0.96, p=0.01. However, no significant association was observed between the other two variants and AEDs resistance. Of their haplotypes in ABCB1 gene (all studies were in Indians and Asians, no significant association was observed with AEDs resistance. Moreover, sensitivity and Cumulative analysis showed that the results of this meta-analysis were stable.In summary, this meta-analysis demonstrated that effect of C3435T variant on risk of AEDs resistance was ethnicity-dependent, which was significant in Caucasians. Additionally, further studies in different ethnic groups are warranted to clarify possible roles of haplotypes in ABCB1 gene in AEDs resistance, especially in Caucasians.

  10. Abcb1 in Pigs: Molecular cloning, tissues distribution, functional analysis, and its effect on pharmacokinetics of enrofloxacin.

    Guo, Tingting; Huang, Jinhu; Zhang, Hongyu; Dong, Lingling; Guo, Dawei; Guo, Li; He, Fang; Bhutto, Zohaib Ahmed; Wang, Liping

    2016-01-01

    P-glycoprotein (P-gp) is one of the best-known ATP-dependent efflux transporters, contributing to differences in pharmacokinetics and drug-drug interactions. Until now, studies on pig P-gp have been scarce. In our studies, the full-length porcine P-gp cDNA was cloned and expressed in a Madin-Darby Canine Kidney (MDCK) cell line. P-gp expression was then determined in tissues and its role in the pharmacokinetics of oral enrofloxacin in pigs was studied. The coding region of pig Abcb1 gene was 3,861 bp, encoding 1,286 amino acid residues (Mw = 141,966). Phylogenetic analysis indicated a close evolutionary relationship between porcine P-gp and those of cow and sheep. Pig P-gp was successfully stably overexpressed in MDCK cells and had efflux activity for rhodamine 123, a substrate of P-gp. Tissue distribution analysis indicated that P-gp was highly expressed in brain capillaries, small intestine, and liver. In MDCK-pAbcb1 cells, enrofloxacin was transported by P-gp with net efflux ratio of 2.48 and the efflux function was blocked by P-gp inhibitor verapamil. High expression of P-gp in the small intestine could modify the pharmacokinetics of orally administrated enrofloxacin by increasing the Cmax, AUC and Ka, which was demonstrated using verapamil, an inhibitor of P-gp. PMID:27572343

  11. Reduced inflammatory response in cigarette smoke exposed Mrp1/Mdr1a/1b deficient mice

    Postma Dirkje S

    2007-07-01

    Full Text Available Abstract Background Tobacco smoke is the principal risk factor for chronic obstructive pulmonary disease (COPD, though the mechanisms of its toxicity are still unclear. The ABC transporters multidrug resistance-associated protein 1 (MRP1 and P-glycoprotein (P-gp/MDR1 extrude a wide variety of toxic substances across cellular membranes and are highly expressed in bronchial epithelium. Their impaired function may contribute to COPD development by diminished detoxification of noxious compounds in cigarette smoke. Methods We examined whether triple knock-out (TKO mice lacking the genes for Mrp1 and Mdr1a/1b are more susceptible to develop COPD features than their wild-type (WT littermates. TKO and WT mice (six per group were exposed to 2 cigarettes twice daily by nose-only exposure or room air for 6 months. Inflammatory infiltrates were analyzed in lung sections, cytokines and chemokines in whole lung homogenates, emphysema by mean linear intercept. Multiple linear regression analysis with an interaction term was used to establish the statistical significances of differences. Results TKO mice had lower levels of interleukin (IL-7, KC (mouse IL-8, IL-12p70, IL-17, TNF-alpha, G-CSF, GM-CSF and MIP-1-alpha than WT mice independent of smoke exposure (P P P Conclusion Mrp1/Mdr1a/1b knock-out mice have a reduced inflammatory response to cigarette smoke. In addition, the expression levels of several cytokines and chemokines were also lower in lungs of Mrp1/Mdr1a/1b knock-out mice independent of smoke exposure. Further studies are required to determine whether dysfunction of MRP1 and/or P-gp contribute to the pathogenesis of COPD.

  12. Substrate-specific effects of pirinixic acid derivatives on ABCB1-mediated drug transport.

    Michaelis, Martin; Rothweiler, Florian; Wurglics, Mario; Aniceto, Natália; Dittrich, Michaela; Zettl, Heiko; Wiese, Michael; Wass, Mark; Ghafourian, Taravat; Schubert-Zsilavecz, Manfred; Cinatl, Jindrich

    2016-03-01

    Pirinixic acid derivatives, a new class of drug candidates for a range of diseases, interfere with targets including PPARα, PPARγ, 5-lipoxygenase (5-LO), and microsomal prostaglandin and E2 synthase-1 (mPGES1). Since 5-LO, mPGES1, PPARα, and PPARγ represent potential anti-cancer drug targets, we here investigated the effects of 39 pirinixic acid derivatives on prostate cancer (PC-3) and neuroblastoma (UKF-NB-3) cell viability and, subsequently, the effects of selected compounds on drug-resistant neuroblastoma cells. Few compounds affected cancer cell viability in low micromolar concentrations but there was no correlation between the anti-cancer effects and the effects on 5-LO, mPGES1, PPARα, or PPARγ. Most strikingly, pirinixic acid derivatives interfered with drug transport by the ATP-binding cassette (ABC) transporter ABCB1 in a drug-specific fashion. LP117, the compound that exerted the strongest effect on ABCB1, interfered in the investigated concentrations of up to 2μM with the ABCB1-mediated transport of vincristine, vinorelbine, actinomycin D, paclitaxel, and calcein-AM but not of doxorubicin, rhodamine 123, or JC-1. In silico docking studies identified differences in the interaction profiles of the investigated ABCB1 substrates with the known ABCB1 binding sites that may explain the substrate-specific effects of LP117. Thus, pirinixic acid derivatives may offer potential as drug-specific modulators of ABCB1-mediated drug transport. PMID:26887049

  13. Role of hypoxia-inducible factor-α in hepatitis-B-virus X protein-mediated MDR1 activation

    The transition from chemotherapy-responsive cancer cells to chemotherapy-resistant cancer cells is mainly accompanied by the increased expression of multi-drug resistance 1 (MDR1). We found that hepatitis-B-virus X protein (HBx) increases the transcriptional activity and protein level of MDR1 in a hepatoma cell line, H4IIE. In addition, HBx overexpression made H4IIE cells more resistant to verapamil-uptake. HBx stabilized hypoxia-inducible factor-1α (HIF-1α) and induced the nuclear translocation of C/EBPβ. Reporter gene analyses showed that HBx increased the reporter activity in the cells transfected with the reporter containing MDR1 gene promoter. Moreover, the luciferase reporter gene activity was significantly inhibited by HIF-1α siRNA but not by overexpression of C/EBP dominant negative mutant. These results imply that HBx increases the MDR1 transporter activity through the transcriptional activation of the MDR1 gene with HIF-1α activation, and suggest HIF-1α for the therapeutic target of HBV-mediated chemoresistance

  14. Polymorphisms in the xenobiotic transporter Multidrug Resistance 1 (MDR1) and interaction with meat intake in relation to risk of colorectal cancer in a Danish prospective case-cohort study

    The xenobiotic transporters, Multidrug Resistance 1 (MDR1/ABCB1) and Breast Cancer Resistance Protein (BCRP/ABCG2) may restrict intestinal absorption of various carcinogens, including heterocyclic amines (HCA) and polycyclic aromatic hydrocarbons (PAH). Cyclooxygenase-2 (COX-2) derived prostaglandins promote gastrointestinal carcinogenesis, affecting angiogenesis, apoptosis, and invasiveness. The aim of this study was to investigate if polymorphisms in these genes were associated with risk of colorectal cancer (CRC), and to investigate possible interactions with lifestyle factors such as smoking, meat consumption, and NSAID use. The following polymorphisms were analyzed; a synonymous MDR1 C3435T (rs1045642) in exon26, G-rs3789243-A in intron3, the functional BCRP C421A (rs2231142), the two COX-2 A-1195G (rs689466) and G-765C (rs20417) in the promoter region, and the COX-2 T8473C (rs5275) polymorphisms in the 3'-untranslated region. The polymorphisms were assessed together with lifestyle factors in a nested case-cohort study of 359 cases and a random cohort sample of 765 participants from the Danish prospective Diet, Cancer and Health study. Carriers of the variant allele of MDR1 intron 3 polymorphism were at 1.52-fold higher risk of CRC than homozygous wild type allele carriers (Incidence rate ratio (IRR) = 1.52, 95% Confidence Interval (CI): 1.12-2.06). Carriers of the variant allele of MDR1 C3435T exon 26 had a lower risk of CRC than homozygous C-allele carriers (IRR = 0.71 (CI:0.50-1.00)). There was interaction between these MDR1 polymorphisms and intake of red and processed meat in relation to CRC risk. Homozygous MDR1 C3435T C-allele carriers were at 8% increased risk pr 25 gram meat per day (CI: 1.00-1.16) whereas variant allele carriers were not at increased risk (p for interaction = 0.02). COX-2 and BCRP polymorphisms were not associated with CRC risk. There was interaction between NSAID use and MDR1 C3435T and COX-2 T8473C (p-values for interaction 0

  15. Polymorphisms in the xenobiotic transporter Multidrug Resistance 1 (MDR1 and interaction with meat intake in relation to risk of colorectal cancer in a Danish prospective case-cohort study

    Overvad Kim

    2009-11-01

    Full Text Available Abstract Background The xenobiotic transporters, Multidrug Resistance 1 (MDR1/ABCB1 and Breast Cancer Resistance Protein (BCRP/ABCG2 may restrict intestinal absorption of various carcinogens, including heterocyclic amines (HCA and polycyclic aromatic hydrocarbons (PAH. Cyclooxygenase-2 (COX-2 derived prostaglandins promote gastrointestinal carcinogenesis, affecting angiogenesis, apoptosis, and invasiveness. The aim of this study was to investigate if polymorphisms in these genes were associated with risk of colorectal cancer (CRC, and to investigate possible interactions with lifestyle factors such as smoking, meat consumption, and NSAID use. Methods The following polymorphisms were analyzed; a synonymous MDR1 C3435T (rs1045642 in exon26, G-rs3789243-A in intron3, the functional BCRP C421A (rs2231142, the two COX-2 A-1195G (rs689466 and G-765C (rs20417 in the promoter region, and the COX-2 T8473C (rs5275 polymorphisms in the 3'-untranslated region. The polymorphisms were assessed together with lifestyle factors in a nested case-cohort study of 359 cases and a random cohort sample of 765 participants from the Danish prospective Diet, Cancer and Health study. Results Carriers of the variant allele of MDR1 intron 3 polymorphism were at 1.52-fold higher risk of CRC than homozygous wild type allele carriers (Incidence rate ratio (IRR = 1.52, 95% Confidence Interval (CI: 1.12-2.06. Carriers of the variant allele of MDR1 C3435T exon 26 had a lower risk of CRC than homozygous C-allele carriers (IRR = 0.71 (CI:0.50-1.00. There was interaction between these MDR1 polymorphisms and intake of red and processed meat in relation to CRC risk. Homozygous MDR1 C3435T C-allele carriers were at 8% increased risk pr 25 gram meat per day (CI: 1.00-1.16 whereas variant allele carriers were not at increased risk (p for interaction = 0.02. COX-2 and BCRP polymorphisms were not associated with CRC risk. There was interaction between NSAID use and MDR1 C3435T and COX-2 T

  16. Avermectin transepithelial transport in MDR1- and MRP-transfected canine kidney monolayers.

    Brayden, David J; Griffin, Joanna

    2008-01-01

    Fluxes of the anti-parasitic agents, [(3)H]-ivermectin, [(3)H]-selamectin and [(3)H]-moxidectin were studied across non-transfected and transfected canine kidney epithelial monolayers, MDCK II/wt, MDCK II-MDR1, MDCK II-MRP1 and MDCK II-MRP2. All four lines surprisingly expressed significant levels of P-glycoprotein (P-gp), coded for by MDR1, but MDCK II-MDR1 expressed increased levels compared to the other lines. MDCK II-MRP1 and MDCK II-MRP2 expressed increased levels of MRP1 and MRP2 respectively. Fluxes of [(3)H]-ivermectin, [(3)H]-selamectin, [(3)H]-moxidectin, and the P-gp substrates, rhodamine-123 and DiOC(2), were polarized in the basolateral-to-apical (secretory) direction across the four lines. Selected MRP inhibitors used in relevant pharmacological concentrations did not block the secretory fluxes of either [(3)H]-ivermectin or [(3)H]-selamectin in either the non-transfected or MRP-transfected lines. In contrast, secretory fluxes of ivermectin and selamectin were inhibited in all four lines by the P-gp inhibitor, verapamil. These data confirm that ivermectin and selamectin are substrates for P-gp in four additional cell lines, but suggest that they are not significant substrates for MRP1 or MRP2 where there is background expression of P-gp. Since this pattern of expression also pertains on the blood-brain barrier, it is unlikely that MRP1 and MRP2 play a significant role in ivermectin and selamectin blood: brain distribution in vivo. PMID:17578674

  17. Novel insertion mutation of ABCB1 gene in an ivermectin-sensitive Border Collie.

    Han, Jae-Ik; Son, Hyoung-Won; Park, Seung-Cheol; Na, Ki-Jeong

    2010-12-01

    P-glycoprotein (P-gp) is encoded by the ABCB1 gene and acts as an efflux pump for xenobiotics. In the Border Collie, a nonsense mutation caused by a 4-base pair deletion in the ABCB1 gene is associated with a premature stop to P-gp synthesis. In this study, we examined the full-length coding sequence of the ABCB1 gene in an ivermectin-sensitive Border Collie that lacked the aforementioned deletion mutation. The sequence was compared to the corresponding sequences of a wild-type Beagle and seven ivermectin-tolerant family members of the Border Collie. When compared to the wild-type Beagle sequence, that of the ivermectin-sensitive Border Collie was found to have one insertion mutation and eight single nucleotide polymorphisms (SNPs) in the coding sequence of the ABCB1 gene. While the eight SNPs were also found in the family members' sequences, the insertion mutation was found only in the ivermectin-sensitive dog. These results suggest the possibility that the SNPs are species-specific features of the ABCB1 gene in Border Collies, and that the insertion mutation may be related to ivermectin intolerance. PMID:21113104

  18. Association of ABCB1 and ABCG2 single nucleotide polymorphisms with clinical findings and response to chemotherapy treatments in Kurdish patients with breast cancer.

    Ghafouri, Houshiyar; Ghaderi, Bayazid; Amini, Sabrieh; Nikkhoo, Bahram; Abdi, Mohammad; Hoseini, Abdolhakim

    2016-06-01

    The possible interaction between gene polymorphisms and risk of cancer progression is very interesting. Polymorphisms in multi-drug resistance genes have an important role in response to anti-cancer drugs. The present study was aimed to evaluate the possible effects of ABCB1 C3435T and ABCG2 C421A single nucleotide polymorphisms on clinical and pathological outcomes of Kurdish patients with breast cancer. One hundred breast cancer patients and 200 healthy controls were enrolled in this case-control study. Clinical and pathological findings of all individuals were reported, and immunohistochemistry staining was used to assess the tissue expression of specific breast cancer proteins. The ABCB1 C3435T and ABCG2 C421 genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism method (PCR-RFLP). The distribution of different genotypes between patient and control groups was only significant for ABCG2 C421A. A allele of ABCG2 C421A polymorphisms were significantly higher in patients than in controls. Patients with AA genotype of ABCG2 C421A were at higher risk of progressing breast cancer. Patients with A allele of ABCG2 had complete response to chemotherapeutic agents. There was no statistically significant association between ABCB1 C3435T and ABCG2 C421A polymorphisms and tissue expression of ER, PR, Her2/neu, and Ki67. The ABCB1 C3435T has no correlation with clinical findings and treatment with chemotherapy drugs. The A allele of ABCG2 C421A may be a risk factor for progression of breast cancer in Kurdish patients. In addition, breast cancer patients with C allele of this polymorphism have weaker response to treatments with anthracyclines and Paclitaxol. PMID:26700668

  19. Bullatacin Triggered ABCB1-Overexpressing Cell Apoptosis via the Mitochondrial-Dependent Pathway

    Yong-Ju Liang

    2009-01-01

    Full Text Available This paper was to explore bullatacin-mediated multidrug-resistant cell apoptosis at extremely low concentration. To investigate its precise mechanisms, the pathway of cell apoptosis induced by bullatacin was examined. Bullatacin causes an upregulation of ROS and a downregulation of ΔΨm in a concentration-dependent manner in ABCB1-overexpressing KBv200 cells. In addition, cleavers of caspase-9, caspase-3, and PARP were observed following the release of cytochrome c from mitochondria after bullatacin treatment. However, neither cleavage of caspase-8 nor change of expression level of bcl-2, bax and Fas was observed by the same treatment. Pretreating KBv200 cells with N-acetylcysteine, an antioxidant modulator, resulted in a significant reduction of ROS generation and cell apoptosis induced by bullatacin. Bullatacin-induced apoptosis was antagonized by z-LEHD-fmk, a caspase-9 inhibitor, but not by z-IETD-fmk, a caspase-8 inhibitor. These implied that apoptosis of KBv200 cells induced by bullatacin was associated with the mitochondria-dependent pathway that was limited to activation of apical caspase-9.

  20. Effect of multidrug resistance gene-1(mdr1) overexpression on in-vitro uptake of {sup 99m}Tc-sestaMIBI in murine L1210 leukemia cells

    Chun, Kyung Ah; Lee, Jae Tae; Lee, Sang Woo; Kang, Do Young; Sohn, Snag Kyun; Lee, Jong Kee; Jun, Soo Han; Lee, Kyu Bo [College of Medicine, Kyungpook National Univ., Taegu (Korea, Republic of); Chung, June Key [College of Medicine, Seoul National Univ., Seoul (Korea, Republic of)

    1999-02-01

    To determine whether {sup 99m}Tc-MIBI is recognized by the multidrug resistant P-glycoprotein (Pgp), we have measured quantitatively {sup 99m}Tc-MIBI uptake in cancer cells. The effects of various Pgp reversing agents on cellular {sup 99m}Tc-MIBI uptake were also investigated in the presence of multidrug resistance gene-1 (mdr 1 gene) overexpression. We measured percentage uptake of {sup 99m}Tc-MIBI at different incubation temperatures both in mdr1 positive and negative cells. The effects of verapamil, cyclosporin, and dipyridamole on cellular uptake of {sup 99m}Tc-MIBI were also evaluated with or without overexpression of mdr1 gene in cultured murine leukemia L1210 cells. The mdr1 gene expressing cell lines were effectively induced in in vitro with continuous application of low-dose adriamycin or vincristine. Cellular uptake of {sup 99m}Tc-MIBI was higher in mdr1 negative L1210 cells than those of mdr1 positive cells, and higher when incubated in 37 .deg. C than 4 .deg. C. In the presence of verapamil, cyclosporin or dipyridamole, {sup 99m}Tc-MIBI uptake was increased upto 604% in mdr1 positive cells. Cellular uptake of {sup 99m}Tc-MIBI is lower in leukemia cells over-expressing mdr1 gene, and MDR-reversing agents increase cellular uptake. These results suggest the {sup 99m}Tc-MIBI can be used for characterizing Pgp expression and developing MDR-reversing agents in vitro.

  1. Genotype frequencies of polymorphic MDR1 variants in the Kazakhstani population

    Samat Kozhakhmetov

    2014-03-01

    Full Text Available Introduction: Statins appear to be handled by an ATP-dependent membrane transporter and three SNPs (C1236T (rs1128503, G2677T (rs2032582, and C3435T (rs1045642, which capture the common genetic variation at this locus. Individuals, who carry the T allele at each SNP (i.e., the T-T-T haplotype, have higher systemic exposure to simvastatin. A triallelic thymine (T - guanine (G - adenine (A, which is  a point mutation at nucleotide 2677 in exon 22, leads to ABCB1 in a non-synonymous codons (GCT alanine, TCT serine, threonine ACT at position 893 in a cytoplasmic loop of ATP-dependent membrane transporters. Methods: Blood samples from healthy individuals were collected in the Republican Diagnostic Center, Astana, Kazakhstan. The research samples included 461 healthy people. Genomic DNA was extracted from peripheral blood using the ‘salting out’ procedure. For the MDR1 exon 21, 2677G˃T/A (Ala893Ser/Thr polymorphism was genotyped by PCR sequencing by the use of dye-terminator (ABI 3730xl sequencer. Results: The GG allele appeared in 23% of samples, the GA in 6.7%, the GT in 44%, the non-G heterozygote in 4.5%, and the non-G homozygote in 18%. These results are consistent with previously published data. Importantly, the frequency of 2677T alleles in our group was 15.4%. This represents the lowest frequency of this allele compared to published data in different populations. The frequency of the 2677T allele in Asians and Caucasians varies from 38 to 62%, and is 15% for African Americans. On the other hand, the 2677A allele frequency in the Japanese varies from 15 to 22%, and in Caucasians from 2% and 4%. The 2677A allele frequency has been found in 4.6% of samples. Conclusions: Our study further emphasizes differences between various Asian populations and the importance of repeating this genetic study  in different ethnic groups.

  2. Timosaponin A-III reverses multi-drug resistance in human chronic myelogenous leukemia K562/ADM cells via downregulation of MDR1 and MRP1 expression by inhibiting PI3K/Akt signaling pathway.

    Chen, Jie-Ru; Jia, Xiu-Hong; Wang, Hong; Yi, Ying-Jie; Wang, Jian-Yong; Li, You-Jie

    2016-05-01

    One of the major causes of failure in chemotherapy for patients with human chronic myelogenous leukemia (CML) is the acquisition of multidrug resistance (MDR). MDR is often associated with the overexpression of drug efflux transporters of the ATP-binding cassette (ABC) protein family. Timosaponin A-III (TAIII), a saponin isolated from the rhizome of Anemarrhena asphodeloides, has previously demonstrated the ability to suppress certain human tumor processes and the potential to be developed as an anticancer agent. Nevertheless, the ability of TAIII to reverse MDR has not yet been explored. In this study, the adriamycin (ADM) resistance reversal effect of TAIII in human CML K562/ADM cells and the underlying mechanism was investigated. The Cell Counting Kit-8 (CCK-8) assay showed that TAIII had a reversal effect on the drug resistance of K562/ADM cells. Flow cytometry assay showed increased intracellular accumulation of ADM after cells were pretreated with TAIII, and the changes in the accumulation of rhodamine-123 (Rho-123) and 5(6)-carboxyfluorescein diacetate (CFDA) dye in K562/ADM cells were determined to be similar to the changes of intracellular accumulation of ADM. After pretreatment of cells with TAIII, the decreasing expression of P-gp and MRP1 mRNA was examined by reverse transcription polymerase chain reaction (RT-PCR). Western blotting showed TAIII inhibiting P-gp and MRP1 expression depended on the PI3K/Akt signaling pathway by decreasing the activity of p-Akt. Moreover, wortmannin an inhibitor of PI3K/Akt signaling pathway has a strong inhibitory effect on the expression of p-Akt, P-gp and MRP1. Besides, the combined treatment with TAIII did not have an affect on wortmannin downregulation of p-Akt, P-gp and MRP1. Taken together, our findings demonstrate, for the first time, that TAIII induced MDR reversal through inhibition of P-gp and MRP1 expression and function with regained adriamycin sensitivity which might mainly correlate to the regulation of PI3K

  3. ABCB1 haplotype and OPRM1 118A > G genotype interaction in methadone maintenance treatment pharmacogenetics

    Barratt DT

    2012-04-01

    Full Text Available Daniel T Barratt1, Janet K Coller1, Richard Hallinan2, Andrew Byrne2, Jason M White1, David JR Foster3, Andrew A Somogyi1,41Discipline of Pharmacology, School of Medical Sciences, University of Adelaide, Adelaide, South Australia; 2The Byrne Surgery, Specialist Drug and Alcohol Practice, Redfern, New South Wales; 3Division of Health Sciences, Sansom Institute, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia; 4Department of Clinical Pharmacology, Royal Adelaide Hospital, Adelaide, South Australia, AustraliaBackground: Genetic variability in ABCB1, encoding the P-glycoprotein efflux transporter, has been linked to altered methadone maintenance treatment dose requirements. However, subsequent studies have indicated that additional environmental or genetic factors may confound ABCB1 pharmacogenetics in different methadone maintenance treatment settings. There is evidence that genetic variability in OPRM1, encoding the mu opioid receptor, and ABCB1 may interact to affect morphine response in opposite ways. This study aimed to examine whether a similar gene-gene interaction occurs for methadone in methadone maintenance treatment.Methods: Opioid-dependent subjects (n = 119 maintained on methadone (15–300 mg/day were genotyped for five single nucleotide polymorphisms of ABCB1 (61A > G; 1199G > A; 1236C > T; 2677G > T; 3435C > T, as well as for the OPRM1 18A > G single nucleotide polymorphism. Subjects’ methadone doses and trough plasma (R-methadone concentrations (Ctrough were compared between ABCB1 haplotypes (with and without controlling for OPRM1 genotype, and between OPRM1 genotypes (with and without controlling for ABCB1 haplotype.Results: Among wild-type OPRM1 subjects, an ABCB1 variant haplotype group (subjects with a wild-type and 61A:1199G:1236C:2677T:3435T haplotype combination, or homozygous for the 61A:1199G:1236C:2677T:3435T haplotype had significantly lower doses (median ± standard

  4. The importance of MDR1 gene polymorphisms for tacrolimus dosage.

    Kravljaca, Milica; Perovic, Vladimir; Pravica, Vera; Brkovic, Voin; Milinkovic, Marija; Lausevic, Mirjana; Naumovic, Radomir

    2016-02-15

    Polymorphisms of the multi drug resistance (MDR1) gene cause variability in P-glycoprotein mediated metabolism of tacrolimus. The aim of this study was to examine the relationship between MDR1 gene single nucleotide polymorphisms (SNPs) and their haplotypes with dosage of tacrolimus in kidney transplant recipients who were cytochrome (CYP) 3A5*3 homozygotes. This study included 91 kidney transplant recipients followed two years after transplantation. Detection and analysis of MDR1 gene polymorphisms in positions C1236T, G2677T/A and C3435T were performed using PCR method. Patients with variant alleles for SNPs G2677T/A and C3435T required higher doses of tacrolimus and had a lower level/dose (L/D) ratio than patients with wild alleles or heterozygotes. That difference was the most obvious for SNP G2677T/A where TT homozygotes required significantly higher doses of tacrolimus during whole follow-up. Their L/D was significantly lower in the first month after transplantation. Recipients with CTT/TTT haplotype also had lower L/D than those with CGC/TTT and CGC/CGC, significantly in the 10th and 20th days after transplantation respectively (p<0.05). Our results demonstrate that TT homozygotes at positions G2677T/A and C3435T required a higher tacrolimus dose than those with wild alleles or heterozygotes. It may be helpful in the prevention of tacrolimus nephrotoxicity early after transplantation. PMID:26705892

  5. Impact of ABCB1 variants on neutrophil depression: a prospective study

    Bergmann, Troels Korshøj; Andersen, Charlotte Brasch; Gréen, Henrik;

    2010-01-01

    hematologic toxicity was registered. Patients carrying one or two variant alleles of ABCB1 C3435T had progressively more pronounced neutrophil decrease at nadir (P-value 0.03). The same association was found for ABCB1 C1236T and G2677T/A with P-values of 0.06 and 0.02. No statistically significant...... a similar result was reported in 18 patients by Sissung et al.(Eur J Cancer 2006;42:2893-6). This novelty has implications for the understanding of myelosuppression in particular and for tailored chemotherapy in general....

  6. Polymorphisms in the ABCB1 gene and effect on outcome and toxicity in childhood acute lymphoblastic leukemia

    Gregers, J; Gréen, H; Christensen, I J;

    2015-01-01

    The membrane transporter P-glycoprotein, encoded by the ABCB1 gene, influences the pharmacokinetics of anti-cancer drugs. We hypothesized that variants of ABCB1 affect outcome and toxicity in childhood acute lymphoblastic leukemia (ALL). We studied 522 Danish children with ALL, 93% of all those e...

  7. Reversal of multidrug resistance in breast cancer MCF-7/ADR cells by h-R3-siMDR1-PAMAM complexes.

    Li, Jun; Liu, Jing; Guo, Nana; Zhang, Xiaoning

    2016-09-10

    Multidrug resistance (MDR) among breast cancer cells is the paramount obstacle for the successful chemotherapy. In this study, anti-EGFR antibody h-R3 was designed to self-assembled h-R3-siRNA-PAMAM-complexes (HSPCs) via electrostatic interactions for siRNA delivery. The physicochemical characterization, cell uptake, MDR1 silencing efficiency, cell migration, cell growth and cell apoptosis were investigated. The HSPCs presented lower cytotoxicity, higher cellular uptake and enhanced endosomal escape ability. Also, HSPCs encapsulating siMDR1 knockdowned 99.4% MDR1 gene with up to ∼6 times of enhancement compared to naked siMDR1, increased the doxorubicin accumulation, down-regulated P-glycoprotein (P-gp) expression and suppressed cellular migration in breast cancer MCF-7/ADR cells. Moreover, the combination of anticancer drug paclitaxel (PTX) and siMDR1 loaded HSPCs showed synergistic effect on overcoming MDR, which inhibited cell growth and induced cell apoptosis. This h-R3-mediated siMDR1 delivery system could be a promising vector for effective siRNA therapy of drug resistant breast cancer. PMID:27444552

  8. HIF-1α inhibition reverses multidrug resistance in colon cancer cells via downregulation of MDR1/P-glycoprotein.

    Jianfang Chen

    Full Text Available BACKGROUND: Multidrug resistance (MDR is one of the major reasons chemotherapy-based treatments fail. Hypoxia is generally associated with tumor chemoresistance. However, the correlation between the heterodimeric hypoxia-inducible factor-1 (HIF-1 and the multidrug resistance (MDR1 gene/transporter P-glycoprotein (P-gp remains unclear. This study aims to explore the molecular mechanisms of reversing colon cancer MDR by focusing on the target gene HIF-1α. METHODS: A chemotherapeutic sensitivity assay was used to observe the efficiency of MDR reversal in LoVo multicellular spheroids (MCS. The apoptotic level induced by different drugs was examined by flow cytometry (FCM. Binding of HIF-1α to the MDR1 gene promoter was evaluated by Chromatin immunoprecipitation (ChIP. The relationship between HIF-1α/P-gp expression and sensitivity to chemotherapy was analyzed. RESULTS: The sensitivity of LoVo MCS to all four chemotherapy drugs was decreased to varying degrees under hypoxic conditions. After silencing the HIF-1α gene, the sensitivities of LoVo MCS to all four chemotherapy drugs were restored. The apoptotic levels that all the drugs induced were all decreased to various extents in the hypoxic group. After silencing HIF-1α, the apoptosis level induced by all four chemotherapy drugs increased. The expression of HIF-1α and P-gp was significantly enhanced in LoVo MCS after treatment with hypoxia. Inhibiting HIF-1α significantly decreased the expression of MDR1/P-gp mRNA or protein in both the LoVo monolayers and LoVo MCS. The ChIP assay showed that HIF-1α was bound to the MDR1 gene promoter. Advanced colon carcinoma patients with expression of both HIF-1α and P-gp were more resistant to chemotherapy than that with non expression. CONCLUSIONS: HIF-1α inhibition reverses multidrug resistance in colon cancer cells via downregulation of MDR1/P-gp. The expression of HIF-1α and MDR1/P-gp can be used as a predictive marker for chemotherapy resistance

  9. Therapeutic efifcacy and bone marrow protection of the mdr1 gene and over-dose chemotherapy with doxorubicin for rabbits with VX2 hepatocarcinoma

    Yi Wang; Xian-Qing Jin; Shan Wang; Qiao Wang; Qing Luo; Xiao-Ji Luo

    2006-01-01

    BACKGROUND: Malignant tumors are common diseases threatening to the health and life of human being. Clinically, the multidrug resistance of tumor cells and bone marrow depression caused by chemotherapeutic agents are the main obstacles to the treatment of tumors, and both are related to the mdr1 gene. The over expression of the mdr1 gene in tumor cells contributes to the multidrug resistance of malignant tumor cells. With little expression of the mdr1 gene, bone marrow cells particularly susceptible to multidrug resistance-sensitive agents, which cause serious toxicity in bone marrow. This study was undertaken to assess therapeutic efifcacy of transplantation of bone marrow mononuclear cells transferred with the mdr1 gene and over-dose chemotherapy with doxorubicin for VX2 hepatocarcinoma of rabbits. METHODS: The mdr1 gene was transferred into the bone marrow mononuclear cells of rabbits, which was co-cultured with retroviral vector-containing supernatant, and the cells were autotransplanted into a rabbit model with VX2 hepatocarcinoma. After chemotherapy with doxorubicin, the protective effects of the mdr1 gene and therapeutic efifcacy of over-dose chemotherapy were observed. RESULTS:The mdr1 gene was transferred successfully into the bone marrow mononuclear cells, with a transduction efifciency of 35%. After autotransplantation, the mdr1 gene was expressed functionally in bone marrow with a positive rate of 8%, indicating that the gene played an important role in bone marrow protection. The rabbits with VX2 hepatocarcinoma, which had received the mdr1 gene-transduced cells, survived after chemotherapy with a 3-fold dose of adriamycin, and their white blood cell counts were (4.26±1.03)×104/L. Since hepatocarcinoma cells were eradicated, the survival time (97.00±46.75 d) of the rabbits was extended (P CONCLUSIONS:The transferring of the mdr1 gene into bone marrow mononuclear cells could confer chemoprotection to bone marrow, and over-dose chemotherapy could be

  10. Ferrocenyl 2,5-Piperazinediones as Tubulin-Binding Organometallic ABCB1 and ABCG2 Inhibitors Active against MDR Cells.

    Wieczorek, Anna; Błauż, Andrzej; Zakrzewski, Janusz; Rychlik, Błażej; Plażuk, Damian

    2016-06-01

    The tubulin-microtubule system is a common target of many anticancer drugs. However, the use of chemotherapeutics frequently leads to the development of a clinically relevant phenomenon of multidrug resistance (MDR). One of the basic mechanisms involved in MDR involves elevated expression and/or activity of several ATP-binding cassette superfamily members (ABC transporters) which are normally responsible for the efflux of xenobiotics or secondary metabolites outside the cell. Here we present the synthesis and biological characteristics of ferrocenyl analogues of plinabulin, i.e. one of the so-called "spindle poisons". We found that replacement of the phenyl group of plinabulin by the ferrocenyl moiety turns this compound into a potent inhibitor of ABCB1 and ABCG2, thus making it possible to overcome the multidrug resistance phenomenon. We also demonstrated that the alkyl group attached to the imidazole moiety of ferrocenyl analogues of plinabulin strongly affects their potency to inhibit tubulin polymerization. PMID:27326336

  11. Oxycodone Induces Overexpression of P-Glycoprotein (ABCB1) and Affects Paclitaxel’s Tissue Distribution in Sprague Dawley Rats

    Hassan, Hazem E.; MYERS, ALAN L.; LEE, INSONG J.; Coop, Andrew; Eddington, Natalie D.

    2007-01-01

    Previous studies suggest that P-glycoprotein (P-gp) modulates the PK/PD of many compounds including opioid agonists and chemotherapeutic agents. The objective of this study was to assess the P-gp affinity status of oxycodone, the P-gp expression, and the paclitaxel’s tissue distribution in oxycodone-treated rats. P-gp ATPase assay, Caco-2 transepithelial permeability studies, and mdr1a/b (−/−) mice were used to assess the P-gp affinity status of oxycodone. P-gp expression was determined by We...

  12. Detection of MDR1 single nucleotide polymorphisms C3435T and G2677T using real-time polymerase chain reaction: MDR1 single nucleotide polymorphism genotyping assay

    Song, Pengfei; Li, Shen; Meibohm, Bernd; Gaber, A. Osama; Honaker, Marsha R.; Kotb, Malak; Yates, Charles R.

    2002-01-01

    The objective of this study was to develop a real-time polymerase chain reaction (PCR) method to detect MDR1 (human multidrug resistance gene) single nucleotide polymorphisms (SNPs) C3435T and G2677T. C3435T and G2677T are linked to MDR1*2, which is associated with enhanced efflux activity in vitro. Using the Smart Cycler, an allele-specific real-time PCR-based genotyping method was developed to detect C3435T and G2677T. The MDR1 genotype of human genomic DNA templates was determined by direc...

  13. Multidrug resistance of DNA-mediated transformants is linked to transfer of the human mdr1 gene.

    Shen, D. W.; Fojo, A; Roninson, I B; Chin, J E; Soffir, R; Pastan, I; Gottesman, M M

    1986-01-01

    Mouse NIH 3T3 cells were transformed to multidrug resistance with high-molecular-weight DNA from multidrug-resistant human KB carcinoma cells. The patterns of cross resistance to colchicine, vinblastine, and doxorubicin hydrochloride (Adriamycin; Adria Laboratories Inc.) of the human donor cell line and mouse recipients were similar. The multidrug-resistant human donor cell line contains amplified sequences of the mdr1 gene which are expressed at high levels. Both primary and secondary NIH 3T...

  14. Gene expression profiling in chemoresistant variants of three cell lines of different origin

    Johnsson, Anders; Vallon-Christensson, Johan; Strand, Carina;

    2005-01-01

    BACKGROUND: Drug resistance is a major problem in clinical cancer chemotherapy. Several mechanisms of resistance have been identified, but the underlying genomic changes are still poorly understood. MATERIALS AND METHODS: Gene expression profiling, using cDNA microarray, was performed in eight cell...... lines (K562 leukemia, MCF-7 breast cancer and S1 colon cancer) with acquired resistance against five cytostatic drugs; daunorubicin (DNR), doxorubicin (DOX), vincristine (VCR), etoposide (VP) and mitoxantrone (MX). RESULTS: The resistant cell lines clustered together based on their type of origin....... Several genes encoding ABC transporters were highly up-regulated, most notably ABCB1 (MDR1) and ABCB4 in several cell lines and ABCG2 (MXR) specifically in MX-resistant cell lines. A pronounced down-regulation of several histones was noted in the MCF-7-derived resistant sublines. Altered expression was...

  15. Pharmacogenetic evaluation of ABCB1, Cyp2C9, Cyp2C19 and methylene tetrahydrofolate reductase polymorphisms in teratogenicity of anti-epileptic drugs in women with epilepsy

    Manna Jose

    2014-01-01

    Full Text Available Aim: Pregnancy in women with epilepsy (WWE who are on anti-epileptic drugs (AEDs has two- to three-fold increased risk of fetal malformations. AEDs are mostly metabolized by Cyp2C9, Cyp2C19 and Cyp3A4 and transported by ABCB1. Patients on AED therapy can have folate deficiency. We hypothesize that the polymorphisms in ABCB1, Cyp2C9, Cyp2C19 and methylene tetrahydrofolate reductase (MTHFR might result in differential expression resulting in differential drug transport, drug metabolism and folate metabolism, which in turn may contribute to the teratogenic impact of AEDs. Materials and Methods: The ABCB1, Cyp2C9, Cyp2C19 and MTHFR polymorphisms were genotyped for their role in teratogenic potential and the nature of teratogenecity in response to AED treatment in WWE. The allelic, genotypic associations were tested in 266 WWE comprising of 143 WWE who had given birth to babies with WWE-malformation (WWE-M and 123 WWE who had normal offsprings (WWE-N. Results: In WWE-M, CC genotype of Ex07 + 139C/T was overrepresented (P = 0.0032 whereas the poor metabolizer allele FNx012 and FNx012 FNx012 genotype of CYP2C219 was significantly higher in comparison to WWE-N group (P = 0.007 and P = 0.005, respectively. All these observations were independent of the nature of malformation (cardiac vs. non cardiac malformations. Conclusion: Our study indicates the possibility that ABCB1 and Cyp2C19 may play a pivotal role in the AED induced teratogenesis, which is independent of nature of malformation. This is one of the first reports indicating the pharmacogenetic role of Cyp2C19 and ABCB1 in teratogenesis of AED in pregnant WWE.

  16. Pilot PET Study to Assess the Functional Interplay Between ABCB1 and ABCG2 at the Human Blood-Brain Barrier.

    Bauer, M; Römermann, K; Karch, R; Wulkersdorfer, B; Stanek, J; Philippe, C; Maier-Salamon, A; Haslacher, H; Jungbauer, C; Wadsak, W; Jäger, W; Löscher, W; Hacker, M; Zeitlinger, M; Langer, O

    2016-08-01

    ABCB1 and ABCG2 work together at the blood-brain barrier (BBB) to limit brain distribution of dual ABCB1/ABCG2 substrates. In this pilot study we used positron emission tomography (PET) to assess brain distribution of two model ABCB1/ABCG2 substrates ([(11) C]elacridar and [(11) C]tariquidar) in healthy subjects without (c.421CC) or with (c.421CA) the ABCG2 single-nucleotide polymorphism (SNP) c.421C>A. Subjects underwent PET scans under conditions when ABCB1 and ABCG2 were functional and during ABCB1 inhibition with high-dose tariquidar. In contrast to the ABCB1-selective substrate (R)-[(11) C]verapamil, [(11) C]elacridar and [(11) C]tariquidar showed only moderate increases in brain distribution during ABCB1 inhibition. This provides evidence for a functional interplay between ABCB1 and ABCG2 at the human BBB and suggests that both ABCB1 and ABCG2 need to be inhibited to achieve substantial increases in brain distribution of dual ABCB1/ABCG2 substrates. During ABCB1 inhibition c.421CA subjects had significantly higher increases in [(11) C]tariquidar brain distribution than c.421CC subjects, pointing to impaired cerebral ABCG2 function. PMID:26940368

  17. Pilot PET Study to Assess the Functional Interplay Between ABCB1 and ABCG2 at the Human Blood–Brain Barrier

    Bauer, M; Römermann, K; Karch, R; Wulkersdorfer, B; Stanek, J; Philippe, C; Maier‐Salamon, A; Haslacher, H; Jungbauer, C; Wadsak, W; Jäger, W; Löscher, W; Hacker, M; Zeitlinger, M

    2016-01-01

    ABCB1 and ABCG2 work together at the blood–brain barrier (BBB) to limit brain distribution of dual ABCB1/ABCG2 substrates. In this pilot study we used positron emission tomography (PET) to assess brain distribution of two model ABCB1/ABCG2 substrates ([11C]elacridar and [11C]tariquidar) in healthy subjects without (c.421CC) or with (c.421CA) the ABCG2 single‐nucleotide polymorphism (SNP) c.421C>A. Subjects underwent PET scans under conditions when ABCB1 and ABCG2 were functional and during ABCB1 inhibition with high‐dose tariquidar. In contrast to the ABCB1‐selective substrate (R)‐[11C]verapamil, [11C]elacridar and [11C]tariquidar showed only moderate increases in brain distribution during ABCB1 inhibition. This provides evidence for a functional interplay between ABCB1 and ABCG2 at the human BBB and suggests that both ABCB1 and ABCG2 need to be inhibited to achieve substantial increases in brain distribution of dual ABCB1/ABCG2 substrates. During ABCB1 inhibition c.421CA subjects had significantly higher increases in [11C]tariquidar brain distribution than c.421CC subjects, pointing to impaired cerebral ABCG2 function. PMID:26940368

  18. HIF-1α/MDR1 pathway confers chemoresistance to cisplatin in bladder cancer.

    Sun, Yi; Guan, Zhenfeng; Liang, Liang; Cheng, Yongyi; Zhou, Jiancheng; Li, Jing; Xu, Yonggang

    2016-03-01

    Bladder cancer (BCa) is the 9th most common malignant tumor and the 13th leading cause of death due to cancer. The development of surgery and target drugs bring new challenges for the traditional concept for BCa therapy, and chemotherapy is still the final option for many BCa patients, and cisplatin-containing regimen the most effective one. However, the ubiquitous application of cisplatin-containing regimen in BCa results in the cisplatin-resistance, in addition, the cisplatin‑resistant BCa manifests enhanced malignant behavior, the mechanism of which is unclear. In the present study, we used BCa cell lines to to clarify this point. BCa cell lines T24/J82 were pretreated with cisplatin >3 months to construct stable cisplatin-resistant cell lines (tagged T24Cis-R and J82Cis-R), which manifested as enhanced capacity of proliferation and malignant behavior in vivo and in vitro, accompanied by cisplatin, and even doxorubicin resistance. The following mechanism dissection revealed that prolonged treatment time of T24/J82 cells led to elevated expression of HIF-1α, which targeted the increased expression of MDR1 on the one hand, and contributed to BCa cell proliferation, migration/invasion on the other hand. Finally, IHC staining of human BCa tissue supported our conclusion that the expression of HIF-1α and MDR1 was higher in chemoresistant tissue vs. chemosensitive tissue. Our results provided a new view of HIF-1α in chemotherapy. PMID:26717965

  19. The biology of MDR1-P-glycoprotein (MDR1-Pgp in designing functional antibody drug conjugates (ADCs: the experience of gemtuzumab ozogamicin

    Maurizio Cianfriglia

    2013-06-01

    Full Text Available BACKGROUND: The treatment of cancer remains a formidable challenge owing to the difficulties in differentiating tumor cells from healthy cells to ameliorate the disease without causing intolerable toxicity to patients. In addition, the emergence of MDR1-Pgp mediated multi-drug resistance (MDR it is a biological phenomenon that inhibits the curative potential of chemotherapeutic treatments. One way to improve the selectivity of therapeutic molecules in tumors would be to target them on the tumor site, thereby sparing normal tissues. AIMS: In this overview, we will discuss the biological factors influencing the safety and efficacy of the humanized mAb hP67.6 linked to the potent cytotoxic drug calicheamicin-gamma1 (gemtuzumab ozogamicin that target CD33 cell surface antigen expressed on AML cells. In addition, we highlight key aspects of MDR1-Pgp biology as a platform to understand its functional role in gemtuzumab ozogamicin immunotherapy which is tightly linked to an accurate assessment of the MDR status of AML cells. DISCUSSION: Several factors may affect the efficacy and safety of immunoconjugates. These include the common issues of chemical and antibody therapeutics such as specificity, heterogeneous target antigen expression and the complex pharmacokinetics profile of conveyed antibody. Further, the delivered drug may not be sufficient for providing therapeutic benefit, since the curative cytotoxic compound may be affected by intrinsic or acquired resistance of target cells. These and other potential problems, as well as the possible ways to overcome them will be discussed in this review by examining the biological factors involved in safety and efficacy of the first in class antibody drug conjugate (ADC gentuzumab ozogamicin. Despite this set-back, the extensive recorded data and the lessons learned from gentuzumab ozogamicin recently withdrawn from the market for safety concerns helped to pave the way for next generations of clinically

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

    Yan YANG; Zehua WANG; Minfang LI; Shi LU

    2009-01-01

    In order to investigate the effect of chitosan/pshR.NA plasmid nanoparticles targeting MDRI genes on the resistance of A2780/TS cells to paclitaxel,chitosan/pshRNA plasmid nanoparticles were synthesized by means of a complex coacervation technique and transfected into A2780/TS cells.The cells transfected with MDR1-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) of paclitaxel 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 IC50 (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.

  1. ABCB1 genotypes and haplotypes in patients with dementia and age-matched non-demented control patients

    Frankfort Suzanne V

    2006-09-01

    Full Text Available Abstract Amyloid β is an in vitro substrate for P-glycoprotein (P-gp, an efflux pump at the blood brain barrier (BBB. The Multi Drug Resistance (ABCB1 gene, encoding for P-gp, is highly polymorphic and this may result in a changed function of P-gp and may possibly interfere with the pathogenesis of Alzheimer's disease. This study investigates to what extent ABCB1 Single Nucleotide Polymorphisms (SNPs; C1236T in exon 12, G2677T/A in exon 21 and C3435T in exon 26 and inferred haplotypes exist in an elderly population and if these SNPs and haplotypes differ between patients with dementia and age-matched non-demented control patients. ABCB1 genotype, allele and haplotype frequencies were neither significantly different between patients with dementia and age-matched controls, nor between subgroups of different types of dementia nor age-matched controls. This study shows ABCB1 genotype frequencies to be comparable with described younger populations. To our knowledge this is the first study on ABCB1 genotypes in dementia. ABCB1 genotypes are presently not useful as a biomarker for dementia, as they were not significantly different between demented patients and age-matched control subjects.

  2. Globally prevalent PfMDR1 mutations modulate Plasmodium falciparum susceptibility to artemisinin-based combination therapies.

    Veiga, M Isabel; Dhingra, Satish K; Henrich, Philipp P; Straimer, Judith; Gnädig, Nina; Uhlemann, Anne-Catrin; Martin, Rowena E; Lehane, Adele M; Fidock, David A

    2016-01-01

    Antimalarial chemotherapy, globally reliant on artemisinin-based combination therapies (ACTs), is threatened by the spread of drug resistance in Plasmodium falciparum parasites. Here we use zinc-finger nucleases to genetically modify the multidrug resistance-1 transporter PfMDR1 at amino acids 86 and 184, and demonstrate that the widely prevalent N86Y mutation augments resistance to the ACT partner drug amodiaquine and the former first-line agent chloroquine. In contrast, N86Y increases parasite susceptibility to the partner drugs lumefantrine and mefloquine, and the active artemisinin metabolite dihydroartemisinin. The PfMDR1 N86 plus Y184F isoform moderately reduces piperaquine potency in strains expressing an Asian/African variant of the chloroquine resistance transporter PfCRT. Mutations in both digestive vacuole-resident transporters are thought to differentially regulate ACT drug interactions with host haem, a product of parasite-mediated haemoglobin degradation. Global mapping of these mutations illustrates where the different ACTs could be selectively deployed to optimize treatment based on regional differences in PfMDR1 haplotypes. PMID:27189525

  3. In vitro detection of mdr1 mRNA in murine leukemia cells with {sup 111}In-labeled oligonucleotide

    Bai Jingming; Yokoyama, Kunihiko; Kinuya, Seigo; Michigishi, Takatoshi; Tonami, Norihisa [Kanazawa University Graduate School of Medical Sciences, Department of Biotracer Medicine (Nuclear Medicine), Kanazawa (Japan); Shiba, Kazuhiro [Kanazawa University, Radioisotope Center, Kanazawa (Japan); Matsushita, Ryo [Kanazawa University, Laboratory for Development of Medicine, Faculty of Pharmaceutical Sciences, Kanazawa (Japan); Nomura, Masaaki [Kanazawa University Hospital, Hospital Pharmacy, Kanazawa (Japan)

    2004-11-01

    The feasibility of intracellular mdr1 mRNA expression detection with radiolabeled antisense oligonucleotide (ODN) was investigated in the murine leukemia cell line, P388/S, and its subclonal, adriamycin-resistant cell line, P388/R. The expression level of mdr1 mRNA was analyzed by reverse transcription-polymerase chain reaction (RT-PCR). Existence of the multidrug resistance (MDR) phenomenon was assessed via cellular uptake of {sup 99m}Tc-sestamibi (MIBI), a known substrate for P-glycoprotein. A 15-mer phosphorothioate antisense ODN complementary to the sequences located at -1 to 14 of mdr1 mRNA and its corresponding sense ODN were conjugated with the cyclic anhydride of diethylene triamine penta-acetic acid (cDTPA) via an amino group linked to the terminal phosphate at the 5' end at pH 8-9. The DTPA-ODN complexes at concentrations of 0.1-17.4 {mu}Mwere reacted with {sup 111}InCl{sub 3} at pH 5 for 1 h. The hybridization affinity of labeled ODN was evaluated with size-exclusion high-performance liquid chromatography following incubation with the complementary sequence. Cellular uptake of labeled ODN was examined in vitro. Furthermore, enhancing effects of synthetic lipid carriers (Transfast) on transmembrane delivery of ODN were assessed. P388/R cells displayed intense mdr1 mRNA expression in comparison with P388/S cells. {sup 99m}Tc-MIBI uptake in P388/S cells was higher than that in P388/R cells. Specific radioactivity up to 1,634 MBq/nmol was achieved via elevation of added radioactivity relative to ODN molar amount. The hybridization affinity of antisense {sup 111}In-ODN was preserved at approximately 85% irrespective of specific activity. Cellular uptake of antisense {sup 111}In-ODN did not differ from that of sense {sup 111}In-ODN in either P388/S cells or P388/R cells. However, lipid carrier incorporation significantly increased transmembrane delivery of {sup 111}In-ODN; moreover, specific uptake of antisense {sup 111}In-ODN was demonstrated in P388/R

  4. Effect of MDR1 gene polymorphisms on mortality in paraquat intoxicated patients

    Kim, Hak Jae; Kim, Hyung-Ki; Kwon, Jun-Tack; Lee, Sun-hyo; el Park, Sam; Gil, Hyo-Wook; Song, Ho-yeon; Hong, Sae-yong

    2016-01-01

    Paraquat is a fatal herbicide following acute exposure. Previous studies have suggested that multidrug resistance protein 1 (MDR1) might help remove paraquat from the lungs and the kidney. MDR1 single-nucleotide polymorphisms (SNPs) are involved in the pharmacokinetics of many drugs. The purpose of this study was to determine whether MDR1 SNPs were associated with the mortality in paraquat intoxicated patients. We recruited 109 patients admitted with acute paraquat poisoning. They were genotyped for C1236T, G2677T/A, and C3435T single-nucleotide polymorphisms (SNPs) of MDR1 gene. Their effects on mortality of paraquat intoxicated patients were evaluated. Overall mortality rate was 66.1%. Regarding the C1236T of the MDR1 gene polymorphism, 21 (19.3%) had the wild type MDR1 while 88 (80.7%) had homozygous mutation. Regarding the C3435T MDR1 gene polymorphism, 37(33.9%) patients had the wild type, 23 (21.1%) had heterozygous mutation, and 49 (45.0%) had homozygous mutation. Regarding the G2677T/A MDR1 gene polymorphism, 38 (34.9%) patients had the wild type, 57 (52.3%) had heterozygous mutation, and 14 (12.8%) had homozygous mutation. None of the individual mutations or combination of mutations (two or three) of MDR1 SNP genotypes altered the morality rate. The mortality rate was not significantly different among SNP groups of patients with MDR1 SNPs have no effect on the mortality rate of paraquat intoxicated patients. PMID:27545861

  5. P-Glycoprotein (Abcb1) is involved in absorptive drug transport in skin

    Ito, Katsuaki; Nguyen, Hai Thien; Kato, Yukio; Wakayama, Tomohiko; Kubo, Yoshiyuki; Iseki, Shoichi; Tsuji, Akira

    2008-01-01

    The purpose of the present study was to investigate the role of P-glycoprotein (P-gp) in drug disposition in skin. The distribution of P-gp substrates (rhodamine 123 and itraconazole) to the skin after administration from the epidermal side was lower in P-gp gene knockout (mdr1a/1b-/-) mice than that in wild-type mice. Coadministration of propranolol, a P-gp inhibitor, decreased the distribution of itraconazole to the skin in wild-type mice, but not in mdr1a/1b-/- mice. These results suggest ...

  6. P-Glycoprotein (Abcb1) is involved in absorptive drug transport in skin

    Ito, Katsuaki; Nguyen, Hai Thien; Kato, Yukio; Wakayama, Tomohiko; Kubo, Yoshiyuki; Iseki, Shoichi; Tsuji, Akira

    2008-01-01

    The purpose of the present study was to investigate the role of P-glycoprotein (P-gp) in drug disposition in skin. The distribution of P-gp substrates (rhodamine 123 and itraconazole) to the skin after administration from the epidermal side was lower in P-gp gene knockout (mdr1a/1b-/- ) mice than that in wild-type mice. Coadministration of propranolol, a P-gp inhibitor, decreased the distribution of itraconazole to the skin in wild-type mice, but not in mdr1a/1b-/- mice. These results suggest...

  7. Importancia pronóstica de la expresión de MDR-1 en la leucemia mieloblástica aguda

    J. Arbelbide

    2003-08-01

    Full Text Available Una proporción importante de pacientes con leucemia mieloblástica aguda (LMA presentan recaída o resistencia con el tratamiento. Uno de los mecanismos involucrados en la resistencia a drogas, es la presencia de la glicoproteína P 170 (gp-P 170 resultante de la expresión del gen MDR-1 sobre las células leucémicas. El objetivo de este trabajo es valorar el impacto pronóstico de la expresión de MDR-1 en una población de pacientes tratados por LMA. Se evaluó retrospectivamente la expresión de MDR-1 en una cohorte de 55 pacientes con LMA, mayores de 16 años, que recibieron tratamiento quimioterápico desde 1990 hasta el 2000. Se evaluó sobre biopsia de médula ósea, la expresión de MDR-1/gp-P 170 por inmunohistoquímica. Mediante una curva ROC, se estableció que una expresión de MDR-1 > 50% en células blásticas, resultó significativa para el logro de remisión completa. Esta expresión de MDR-1+ correlacionó con la presencia de leucocitosis: (p:0.002, expresion de células CD34+ (p:0.006, menor tasa de remisión completa (p:0.001, mayor tasa de recaída (p:0.02 y de estudios citogenéticos no favorables (p:0.02. La SLE fue de 21.2% ES:9.3 con un seguimiento de 22 meses para el grupo MDR-1+ versus 56.4% ES:12.5 con un seguimiento de 78 meses en los casos MDR-1- (p:0.007. Se puede concluir que la expresion de MDR-1 ha demostrado ser un factor pronóstico de resistencia a la quimioterapia. Estos pacientes presentan una menor tasa de remisión completa, una mayor tasa de recaída por persistencia de enfermedad residual post-tratamiento, lo que produce una menor sobrevida global.An important number of patients with Acute Myeloid Leukemia (AML experience relapse or resistance to chemotherapy. One of the mechanisms involved in this resistance is the presence of glycoprotein P170 (gp-P 170, which results of the MDR-1 gene in leukemic cells. The objective of this article is to assess the prognostic impact of the expression of MDR-1 in a

  8. High ABCC2 and Low ABCG2 Gene Expression Are Early Events in the Colorectal Adenoma-Carcinoma Sequence

    Andersen, Vibeke; Vogel, Lotte K.; Kopp, Tine Iskov;

    2015-01-01

    Development of colorectal cancer (CRC) may result from a dysfunctional interplay between diet, gut microbes and the immune system. The ABC transport proteins ABCB1 (P-glycoprotein, Multidrug resistance protein 1, MDR1), ABCC2 (MRP2) and ABCG2 (BCRP) are involved in transport of various compounds...

  9. Association between ABCB1 polymorphisms and haplotypes and Alzheimer's disease: a meta-analysis.

    Zhong, Xin; Liu, Ming-Yan; Sun, Xiao-Hong; Wei, Min-Jie

    2016-01-01

    Although several epidemiological studies have investigated the association between ATP-binding cassette subfamily B member 1 (ABCB1) gene polymorphisms and Alzheimer's disease (AD) susceptibility, controversial results exist. Here, we performed a meta-analysis to assess whether ABCB1 polymorphisms 3435C > T (rs1045642), 2677G > T/A (rs2032582), 1236C > T (rs1128503) and haplotypes were associated with AD risk. Nine independent publications were included and analyzed. Crude odds ratio (OR) and 95% confidence interval (CI) were applied to investigate the strength of the association. Sensitivity analysis was conducted to measure the robustness of our analysis. A funnel plot and trim and fill method were used to test and adjust for publication bias. The results showed a significant association between the 3435C > T single nucleotide polymorphism (SNP) and AD susceptibility (CT vs. CC: OR = 1.24, 95% CI = 1.06-1.45, P = 0.01; CT + TT vs. CC: OR = 1.21, 95% CI = 1.04-1.41, P = 0.01) in the total population, as well as in Caucasian subgroup. The 2677G > T/A SNP was related to a decreased AD risk in Caucasian subgroup (TT + TA + AA vs. GT + GA + GG: OR = 0.68, 95% CI = 0.47-0.98, P = 0.04). Moreover, the ABCB1 haplotype analysis showed that the 1236T/2677T/3435C haplotype was associated with a higher risk of AD (OR = 1.99, 95% CI = 1.24-3.18, P = 0.00). Our results suggest that the ABCB1 3435C > T SNP, the 2677G > T/A SNP and 1236T/2677T/3435C haplotype are significantly associated with AD susceptibility. PMID:27600024

  10. Inducible and Constitutive Activation of Two Polymorphic Promoter Alleles of the Candida albicans Multidrug Efflux Pump MDR1

    Sasse, Christoph; Schillig, Rebecca; Reimund, Alexandra; Merk, Julia; Morschhäuser, Joachim

    2012-01-01

    Overexpression of the multidrug efflux pump MDR1 confers resistance to the antifungal drug fluconazole on Candida albicans. It has been reported that two types of MDR1 promoters exist in C. albicans and that homozygosity for the allele with higher activity may promote fluconazole resistance. We found that the two MDR1 promoter alleles in strain SC5314 were equally well activated by inducing chemicals or hyperactive forms of the transcription factors Mrr1 and Cap1, which control MDR1 expressio...

  11. Down Regulation of CIAPIN1 Reverses Multidrug Resistance in Human Breast Cancer Cells by Inhibiting MDR1

    Xuemei Wang

    2012-06-01

    Full Text Available Cytokine-induced apoptosis inhibitor 1 (CIAPIN1, initially named anamorsin, a newly indentified antiapoptotic molecule is a downstream effector of the receptor tyrosine kinase-Ras signaling pathway. Current study has revealed that CIAPIN1 may have wide and important functions, especially due to its close correlations with malignant tumors. However whether or not it is involved in the multi-drug resistance (MDR process of breast cancer has not been elucidated. To explore the effect of CIAPIN1 on MDR, we examined the expression of P-gp and CIAPIN1 by immunohistochemistry and found there was positive correlation between them. Then we successfully interfered with RNA translation by the infection of siRNA of CIAPIN1 into MCF7/ADM breast cancer cell lines through a lentivirus, and the expression of the target gene was significantly inhibited. After RNAi the drug resistance was reduced significantly and the expression of MDR1mRNA and P-gp in MCF7/ADM cell lines showed a significant decrease. Also the expression of P53 protein increased in a statistically significant way (p ≤ 0.01 after RNAi exposure. In addition, flow cytometry analysis reveals that cell cycle and anti-apoptotic enhancing capability of cells changed after RNAi treatment. These results suggested CIAPIN1 may participate in breast cancer MDR by regulating MDR1 and P53 expression, changing cell cycle and enhancing the anti-apoptotic capability of cells.

  12. PfMDR1: mechanisms of transport modulation by functional polymorphisms.

    Pedro Eduardo Ferreira

    Full Text Available ATP-Binding Cassette (ABC transporters are efflux pumps frequently associated with multidrug resistance in many biological systems, including malaria. Antimalarial drug-resistance involves an ABC transporter, PfMDR1, a homologue of P-glycoprotein in humans. Twenty years of research have shown that several single nucleotide polymorphisms in pfmdr1 modulate in vivo and/or in vitro drug susceptibility. The underlying physiological mechanism of the effect of these mutations remains unclear. Here we develop structural models for PfMDR1 in different predicted conformations, enabling the study of transporter motion. Such analysis of functional polymorphisms allows determination of their potential role in transport and resistance. The bacterial MsbA ABC pump is a PfMDR1 homologue. MsbA crystals in different conformations were used to create PfMDR1 models with Modeller software. Sequences were aligned with ClustalW and analysed by Ali2D revealing a high level of secondary structure conservation. To validate a potential drug binding pocket we performed antimalarial docking simulations. Using aminoquinoline as probe drugs in PfMDR1 mutated parasites we evaluated the physiology underlying the mechanisms of resistance mediated by PfMDR1 polymorphisms. We focused on the analysis of well known functional polymorphisms in PfMDR1 amino acid residues 86, 184, 1034, 1042 and 1246. Our structural analysis suggested the existence of two different biophysical mechanisms of PfMDR1 drug resistance modulation. Polymorphisms in residues 86/184/1246 act by internal allosteric modulation and residues 1034 and 1042 interact directly in a drug pocket. Parasites containing mutated PfMDR1 variants had a significant altered aminoquinoline susceptibility that appears to be dependent on the aminoquinoline lipophobicity characteristics as well as vacuolar efflux by PfCRT. We previously described the in vivo selection of PfMDR1 polymorphisms under antimalarial drug pressure. Now

  13. The search for the mdr1-1Δ mutation of the MDR1 gene in four canine breeds in Uruguay (preliminary study

    Rosa Gagliardi B.

    2015-01-01

    Full Text Available Objective. The objective of this study is to analyze the frequency of mdr1-1Δ mutation in German Shepherd, Doberman, Border Collie and Greyhound dog breeds in Uruguay. Materials and methods. A total of 95 animals from the four breeds mentioned above were studied. DNA was isolated from blood using potassium acetate with a subsequent degradation from RNA with RNAsaH. The concentration and quality of the DNA obtained was evaluated with a Nanodrop, ND-1000 spectrophotometer. To determine the presence or absence of the mdr1-1Δ mutation, DNA samples were sent to Gene Seek, Neogen Corporation of Chicago, United States, for genotyping. Results. In all 95 animals studied, the mdr1-1Δ mutation was not present. Conclusions. Based on the preliminary results obtained, other elements that may cause adverse drug reactions must be considered: unidentified mutations in other regions of the MDR1 gene; mutations in other genes involved in the transport of drugs from the same subfamily or another; mutations in enzymes involved in drug metabolism (e.g. Cytochrome P450. Moreover, especially with Border Collies and Greyhounds, it is advisable to increase the number of animals in the study.

  14. Multi-drug resistance (MDR1 gene and P-glycoprotein influence on pharmacokinetic and pharmacodymanic of therapeutic drugs

    Linardi Renata Lehn

    2006-01-01

    Full Text Available (MDR1 gene expressed in tumor cells and also in several normal tissues, such as intestine, liver, kidney, blood-brain barrier, spinal cord, and placenta. P-gp has been identified in mice, rat, bovine, monkey, rodents, and human beings and has been receiving a particular clinical relevance because this protein expression limits brain access and intestinal absorption of many drugs. This protein plays a role as a protective barrier against a wide variety of substrates, avoiding drug entry into the central nervous system. P-glycoprotein also interferes with drug bioavailability and disposition, including absorption, distribution, metabolization, and excretion, influencing pharmacokinetic and pharmacodynamic of drugs. Modulation of P-gp may help the efficacy of treatment of several diseases and can explain some adverse central nervous system effects induced by drugs after intravenous administration and the poor response of oral administration in patients. Alteration in P-gp expression or function has been associated with several diseases susceptibility in humans and animals. Furthermore, additional studies relating MDR1 and P-gp expression has an important clinical implication also in terms of treatment efficacy.

  15. Cytokine-induced killer cells showing multidrug resistance and remaining cytotoxic activity to tumor cells after transfected with mdr1 cDNA

    李惠芳; 杨永红; 石永进; 王逸群; 朱平

    2004-01-01

    Background Routine treatment of cancer such as surgery, radiation or chemotherapy is sometimes unable to erdiacate metastatic malignant cells. So we tried a new method and increased the adoptive immunotherapy of Cytokine-induced killer (CIK) cells in tumor patients and the multidrug resistance (mdr1) cDNA was transfected into CIK cells. Methods CIK cells were obtained from peripheral blood and induced by IFN-γ, anti-CD3 monoclonal antibody, IL-2 and IL-1. CIK cells were transfected with plasmid PHaMDR containing human mdr1 cDNA by electroporation. RT-PCR was used to detect mdr1 mRNA in transfected CIK cells. P-glycoprotein (P-gp) expressed on surface of CIK cells was assayed by FITC-conjugated anti-P-gp monoclonal antibody and flow cytometry. Multidrug resistance to doxorubicin and colchicine and cytotoxic activity to human breast cancer cell line MCF7 were performed using MTT method.Results mdr1 mRNA was detected in transfected CIK cells. P-gp was expressed on the surface of the transfected CIK cells, and the P-gp positive cells reached 21%-37% of the total CIK cells after transfection. The IC50 to doxorubicin increased to 22.3-45.8 times, and that to colchicines to 6.7-11.35 times, as compared to those of untransfected CIK cells. However, the cytotoxic activity to MCF7 cell line remained unaltered.Conclusions CIK cells were successfully transfected with mdr1 cDNA by using electroporation. The transfected CIK cells had the characteristics of multidrug resistance without change in their cytotoxic activity to tumor cells.

  16. Relative neurotoxicity of ivermectin and moxidectin in Mdr1ab (-/- mice and effects on mammalian GABA(A channel activity.

    Cécile Ménez

    Full Text Available The anthelmintics ivermectin (IVM and moxidectin (MOX display differences in toxicity in several host species. Entrance into the brain is restricted by the P-glycoprotein (P-gp efflux transporter, while toxicity is mediated through the brain GABA(A receptors. This study compared the toxicity of IVM and MOX in vivo and their interaction with GABA(A receptors in vitro. Drug toxicity was assessed in Mdr1ab(-/- mice P-gp-deficient after subcutaneous administration of increasing doses (0.11-2.0 and 0.23-12.9 µmol/kg for IVM and MOX in P-gp-deficient mice and half lethal doses (LD(50 in wild-type mice. Survival was evaluated over 14-days. In Mdr1ab(-/- mice, LD(50 was 0.46 and 2.3 µmol/kg for IVM and MOX, respectively, demonstrating that MOX was less toxic than IVM. In P-gp-deficient mice, MOX had a lower brain-to-plasma concentration ratio and entered into the brain more slowly than IVM. The brain sublethal drug concentrations determined after administration of doses close to LD(50 were, in Mdr1ab(-/- and wild-type mice, respectively, 270 and 210 pmol/g for IVM and 830 and 740-1380 pmol/g for MOX, indicating that higher brain concentrations are required for MOX toxicity than IVM. In rat α1β2γ2 GABA channels expressed in Xenopus oocytes, IVM and MOX were both allosteric activators of the GABA-induced response. The Hill coefficient was 1.52±0.45 for IVM and 0.34±0.56 for MOX (p<0.001, while the maximum potentiation caused by IVM and MOX relative to GABA alone was 413.7±66.1 and 257.4±40.6%, respectively (p<0.05, showing that IVM causes a greater potentiation of GABA action on this receptor. Differences in the accumulation of IVM and MOX in the brain and in the interaction of IVM and MOX with GABA(A receptors account for differences in neurotoxicity seen in intact and Mdr1-deficient animals. These differences in neurotoxicity of IVM and MOX are important in considering their use in humans.

  17. Epoxylathyrol Derivatives: Modulation of ABCB1-Mediated Multidrug Resistance in Human Colon Adenocarcinoma and Mouse T-Lymphoma Cells.

    Matos, Ana M; Reis, Mariana; Duarte, Noélia; Spengler, Gabriella; Molnár, Joseph; Ferreira, Maria-José U

    2015-09-25

    Epoxyboetirane A (1), a macrocyclic diterpene that was found to be inactive as an ABCB1 modulator, was submitted to several chemical transformations, aimed at generating a series of compounds with improved multidrug resistance (MDR)-modifying activity. Overall, 23 new derivatives were prepared, in addition to the already reported epoxylathyrol (2) and methoxyboetirol (3). Their anti-MDR potential was assessed through both functional and chemosensitivity assays on resistant human colon adenocarcinoma and human ABCB1-gene transfected L5178Y mouse lymphoma cells. Structure-activity relationship analysis showed that different substitution patterns led to distinct ABCB1 inhibitory activities, although intrinsic cellular characteristics seemed to influence the modulatory behavior. A considerable enhancement in MDR-modifying activity was observed for aromatic compounds in both cell lines, particularly in 3,17-disubstituted esters derived from 3, a Payne-rearranged Michael adduct of 2. All compounds tested were revealed to interact synergistically with doxorubicin, and ATPase inhibition by three representative MDR-modifying compounds was also investigated. On account of its outstanding ABCB1 inhibitory activity at 0.2 μM and overall remarkable bioactive profile, methoxyboetirane B (22) was found to be a new promising lead for MDR-reversing anticancer drug development. PMID:26331763

  18. Arabidopsis TWISTED DWARF1 functionally interacts with Auxin Exporter ABCB1 on the root plasma membrane

    Wang, Bangjun; Bailly, Aurélien; Zwiewka, Marta;

    2013-01-01

    . In planta bioluminescence resonance energy transfer analysis was used to verify specific ABC transporter B1 (ABCB1)-TWD1 interaction. Our data support a model in which TWD1 promotes lateral ABCB-mediated auxin efflux via protein-protein interaction at the plasma membrane, minimizing reflux from the root...

  19. Breed distribution of the nt230(del4) MDR1 mutation in dogs.

    Gramer, Irina; Leidolf, Regina; Döring, Barbara; Klintzsch, Stefanie; Krämer, Eva-Maria; Yalcin, Ebru; Petzinger, Ernst; Geyer, Joachim

    2011-07-01

    A 4-bp deletion mutation associated with multiple drug sensitivity exists in the canine multidrug resistance (MDR1) gene. This mutation has been detected in more than 10 purebred dog breeds as well as in mixed breed dogs. To evaluate the breed distribution of this mutation in Germany, 7378 dogs were screened, including 6999 purebred and 379 mixed breed dogs. The study included dog breeds that show close genetic relationship or share breeding history with one of the predisposed breeds but in which the occurrence of the MDR1 mutation has not been reported. The breeds comprised Bearded Collies, Anatolian Shepherd Dog, Greyhound, Belgian Tervuren, Kelpie, Borzoi, Australian Cattle Dog and the Irish Wolfhound. The MDR1 mutation was not detected is any of these breeds, although it was found as expected in the Collie, Longhaired Whippet, Shetland Sheepdog, Miniature Australian Shepherd, Australian Shepherd, Wäller, White Swiss Shepherd, Old English Sheepdog and Border Collie with varying allelic frequencies for the mutant MDR1 allele of 59%, 45%, 30%, 24%, 22%, 17%, 14%, 4% and 1%, respectively. Allelic frequencies of 8% and 2% were determined in herding breed mixes and unclassified mixed breeds, respectively. Because of its widespread breed distribution and occurrence in many mixed breed dogs, it is difficult for veterinarians and dog owners to recognise whether MDR1-related drug sensitivity is relevant for an individual animal. This study provides a comprehensive overview of all affected dog breeds and many dog breeds that are probably unaffected on the basis of ∼15,000 worldwide MDR1 genotyping data. PMID:20655253

  20. The functional influences of common ABCB1 genetic variants on the inhibition of P-glycoprotein by Antrodia cinnamomea extracts.

    Ming-Jyh Sheu

    Full Text Available Antrodia cinnamomea is a traditional healthy food that has been demonstrated to possess anti-inflammatory, antioxidative, and anticacer effects. The purpose of this study was to evaluate whether the ethanolic extract of A. cinnamomea (EEAC can affect the efflux function of P-glycoprotein (P-gp and the effect of ABCB1 genetic variants on the interaction between EEAC and P-gp. To investigate the mechanism of this interaction, Flp-In™-293 cells stably transfected with various genotypes of human P-gp were established and the expression of P-gp was confirmed by Western blot. The results of the rhodamine 123 efflux assay demonstrated that EEAC efficiently inhibited wild-type P-gp function at an IC50 concentration of 1.51 ± 0.08 µg/mL through non-competitive inhibition. The IC50 concentrations for variant-type 1236T-2677T-3435T P-gp and variant-type 1236T-2677A-3435T P-gp were 5.56 ± 0.49 µg/mL and 3.33±0.67 µg/mL, respectively. In addition, the inhibition kinetics of EEAC also changed to uncompetitive inhibition in variant-type 1236T-2677A-3435T P-gp. The ATPase assay revealed that EEAC was an ATPase stimulator and was capable of reducing verapamil-induced ATPase levels. These results indicate that EEAC may be a potent P-gp inhibitor and higher dosages may be required in subjects carrying variant-types P-gp. Further studies are required to translate this basic knowledge into clinical applications.

  1. Hedgehog Pathway Inhibitor HhAntag691 Is a Potent Inhibitor of ABCG2/BCRP and ABCB1/Pgp

    Yimao Zhang

    2009-01-01

    Full Text Available HhAntag691 (GDC-0449, a low-molecular weight inhibitor of the tumor-promoting hedgehog (Hh signaling pathway, has been used to treat medulloblastoma in animal models and has recently entered clinical trials for a variety of solid tumors. Here, we show that HhAntag691 inhibits multiple ATP-binding cassette (ABC transporters. ATP-binding cassette transporters are within a family of membrane proteins, the overexpression of which is associated with multidrug resistance, a major impediment to successful cancer treatment. HhAntag691 is a potent inhibitor of two ABC transporters, ABCG2/BCRP and ABCB1/Pgp, and is a mild inhibitor of ABCC1/MRP1. In ABCG2-overexpressing HEK293 cells, HhAntag691 increased retention of the fluorescent ABCG2 substrate BODIPY-prazosin and resensitized these cells to mitoxantrone, an antineoplastic ABCG2 substrate. In Madin-Darby canine kidney II cells engineered to overexpress Pgp or MRP1, HhAntag691 increased the retention of calcein-AM and resensitized them to colchicine. HhAntag691 also resensitized human non-small cell lung carcinoma cells NCI-H460/par and NCI-H460/MX20, which overexpress ABCG2 in response to mitoxantrone, to mitoxantrone, and to topotecan or SN-38. The IC50 values of HhAntag691 for inhibition of ABCG2 and Pgp were ∼1.4 and ∼3.0 µM, respectively. Because ABC transporters are highly expressed at the blood-brain barrier and on many tumor cells, they contribute significantly to treatment failure of many types of cancer, particularly of those within the neuraxis. In addition to its effect on Hh signaling, the ability of HhAntag691 and related compounds to inhibit two key ABC transporters could contribute to their effectiveness in treating malignancies.

  2. HIV-1 integrase inhibitors are substrates for the multidrug transporter MDR1-P-glycoprotein

    Cara Andrea

    2007-03-01

    Full Text Available Abstract Background The discovery of diketoacid-containing derivatives as inhibitors of HIV-1 Integrase (IN (IN inhibitors, IINs has played a major role in validating this enzyme as an important target for antiretroviral therapy. Since the in vivo efficacy depends on access of these drugs to intracellular sites where HIV-1 replicates, we determined whether the IINs are recognized by the multidrug transporter MDR1-P-glycoprotein (P-gp thereby reducing their intracellular accumulation. To address the effect of IINs on drug transport, nine quinolonyl diketo acid (DKA derivatives active on the HIV-1 IN strand transfer (ST step and with EC50 ranging from 1.83 to >50 μm in cell-based assays were tested for their in vitro interaction with P-gp in the CEM-MDR cell system. IINs were investigated for the inhibition and induction of the P-gp function and expression as well as for multidrug resistance (MDR reversing ability. Results The HIV-1 IINs act as genuine P-gp substrates by inhibiting doxorubicin efflux and inducing P-gp functional conformation changes as evaluated by the modulation of UIC2 mAb epitope. Further, IINs chemosensitize MDR cells to vinblastine and induce P-gp expression in drug sensitive revertants of CEM-MDR cells. Conclusion To our knowledge, this is the first demonstration that HIV-1 IINs are P-gp substrates. This biological property may influence the absorption, distribution and elimination of these novels anti HIV-1 compounds.

  3. Dioscin strengthens the efficiency of adriamycin in MCF-7 and MCF-7/ADR cells through autophagy induction: More than just down-regulation of MDR1.

    Wang, Changyuan; Huo, Xiaokui; Wang, Lijuan; Meng, Qiang; Liu, Zhihao; Liu, Qi; Sun, Huijun; Sun, Pengyuan; Peng, Jinyong; Liu, Kexin

    2016-01-01

    The purpose of present study was to investigate the effect of dioscin on activity of adriamycin (ADR) in ADR-sensitive (MCF-7) and ADR-resistant (MCF-7/ADR) human breast cancer cells and to clarify the molecular mechanisms involved. Antiproliferation effect of ADR was enhanced by dioscin in MCF-7 and MCF-7/ADR cells. Dioscin significantly inhibited MDR1 mRNA and protein expression and MDR1 promoter and nuclear factor κ-B (NF-κB) activity in MCF-7/ADR cells. Additionally, inhibitor κB-α (IκB-α) degradation was inhibited by dioscin. Moreover, dioscin induced the formation of vacuoles in the cytoplasm and protein level of LC3-II in MCF-7 and MCF-7/ADR cells. Autophagy inhibitor 3-MA abolished the effect of dioscin on ADR cytotoxicity. Dioscin inhibited phosphorylation of PI3K and Akt, resulting in upregulation of LC3-II expression. In conclusion, dioscin increased ADR chemosensitivity by down-regulating MDR1 expression through NF-κB signaling inhibition in MCF-7/ADR cells. Autophagy was induced by dioscin to ameliorate the cytotoxicity of ADR via inhibition of the PI3K/AKT pathways in MCF-7 and MCF-7/ADR cells. These findings provide evidence in support of further investigation into the clinical application of dioscin as a chemotherapy adjuvant. PMID:27329817

  4. Dioscin restores the activity of the anticancer agent adriamycin in multidrug-resistant human leukemia K562/adriamycin cells by down-regulating MDR1 via a mechanism involving NF-κB signaling inhibition.

    Wang, Lijuan; Meng, Qiang; Wang, Changyuan; Liu, Qi; Peng, Jinyong; Huo, Xiaokui; Sun, Huijun; Ma, Xiaochi; Liu, Kexin

    2013-05-24

    The purpose of this study was to investigate the ameliorating effect of dioscin (1) on multidrug resistance (MDR) in adriamycin (ADR)-resistant erythroleukemic cells (K562/adriamycin, K562/ADR) and to clarify the molecular mechanisms involved. High levels of multidrug resistance 1 (MDR1) mRNA and protein and reduced ADR retention were found in K562/ADR cells compared with parental cells (K562). Dioscin (1), a constituent of plants in the genus Discorea, significantly inhibited MDR1 mRNA and protein expression and MDR1 promoter and nuclear factor κ-B (NF-κB) activity in K562/ADR cells. MDR1 mRNA and protein suppression resulted in the subsequent recovery of intracellular drug accumulation. Additionally, inhibitor κB-α (IκB-α) degradation was inhibited by 1. Dioscin (1) reversed ADR-induced MDR by down-regulating MDR1 expression by a mechanism that involves the inhibition of the NF-κB signaling pathway. These findings provide evidence to support the further investigation of the clinical application of dioscin (1) as a chemotherapy adjuvant. PMID:23621869

  5. Effect of dietary fat on hepatic liver X receptor expression in P-glycoprotein deficient mice: implications for cholesterol metabolism

    Lee Stephen D

    2008-06-01

    Full Text Available Abstract Pgp (P-glycoprotein, MDR1, ABCB1 is an energy-dependent drug efflux pump that is a member of the ATP-binding cassette (ABC family of proteins. Preliminary studies have reported that nonspecific inhibitors of Pgp affect synthesis and esterification of cholesterol, putatively by blocking trafficking of cholesterol from the plasma membrane to the endoplasmic reticulum, and that relative increases in Pgp within a given cell type are associated with increased accumulation of cholesterol. Several key efflux proteins involved in the cholesterol metabolic pathway are transcriptionally regulated by the nuclear hormone liver X receptor (LXR. Therefore, to examine the interplay between P-glycoprotein and the cholesterol metabolic pathway, we utilized a high fat, normal cholesterol diet to upregulate LXRα without affecting dietary cholesterol. Our research has demonstrated that mice lacking in P-glycoprotein do not exhibit alterations in hepatic total cholesterol storage, circulating plasma total cholesterol levels, or total cholesterol concentration in the bile when compared to control animals on either a normal (25% calories from dietary fat or high fat (45% calories from dietary fat diet. However, p-glycoprotein deficient mice (Mdr1a-/-/1b-/- exhibit increased hepatic LXRα protein expression and an elevation in fecal cholesterol concentration when compared to controls.

  6. Cisplatin, doxorubicin and paclitaxel induce mdr1 gene transcription in ovarian cancer cell lines.

    Schöndorf, Thomas; Neumann, Rainer; Benz, Carolin; Becker, Martina; Riffelmann, Marion; Göhring, Uwe-Jochen; Sartorius, Judith; von König, Carl-Heinz Wirsing; Breidenbach, Martina; Valter, Markus M; Hoopmann, Markus; Di Nicolantonio, Federica; Kurbacher, Christian M

    2003-01-01

    The clinical observation of the multidrug resistance (MDR) phenotype is often associated with overexpression of the mdrl gene, in particular with respect to ovarian cancer. However, until now the mdrl-inducing potential of commonly used antineoplastics has been only incompletely explored. We performed short-term cultures of six ovarian cancer cell lines (MZOV4, EF027, SKOV3, OAW42, OTN14, MZOV20) exposed to either blank medium or cisplatin, doxorubicin or paclitaxel at concentrations related to the clinically achievable plasma peak concentration. A highly specific quantitative real-time RT-PCR was used to detect the Mdr1 transcripts. Mdrl mRNA contents were calibrated in relation to coamplified GAPDH mRNA. Mdrl mRNA was detectable in each cell line. In 13 out of 18 assays (72%) the specific anticancer drug being tested induced mdr1 transcription. No decrease in mdr1 mRNA concentration was observed. Our data suggest that mdr1 induction by antineoplastics is one of the reasons for failure of ovarian cancer therapy but may vary individually. PMID:12528803

  7. Multiple transport-active binding sites are available for a single substrate on human P-glycoprotein (ABCB1).

    Chufan, Eduardo E; Kapoor, Khyati; Sim, Hong-May; Singh, Satyakam; Talele, Tanaji T; Durell, Stewart R; Ambudkar, Suresh V

    2013-01-01

    P-glycoprotein (Pgp, ABCB1) is an ATP-Binding Cassette (ABC) transporter that is associated with the development of multidrug resistance in cancer cells. Pgp transports a variety of chemically dissimilar amphipathic compounds using the energy from ATP hydrolysis. In the present study, to elucidate the binding sites on Pgp for substrates and modulators, we employed site-directed mutagenesis, cell- and membrane-based assays, molecular modeling and docking. We generated single, double and triple mutants with substitutions of the Y307, F343, Q725, F728, F978 and V982 residues at the proposed drug-binding site with cys in a cysless Pgp, and expressed them in insect and mammalian cells using a baculovirus expression system. All the mutant proteins were expressed at the cell surface to the same extent as the cysless wild-type Pgp. With substitution of three residues of the pocket (Y307, Q725 and V982) with cysteine in a cysless Pgp, QZ59S-SSS, cyclosporine A, tariquidar, valinomycin and FSBA lose the ability to inhibit the labeling of Pgp with a transport substrate, [(125)I]-Iodoarylazidoprazosin, indicating these drugs cannot bind at their primary binding sites. However, the drugs can modulate the ATP hydrolysis of the mutant Pgps, demonstrating that they bind at secondary sites. In addition, the transport of six fluorescent substrates in HeLa cells expressing triple mutant (Y307C/Q725C/V982C) Pgp is also not significantly altered, showing that substrates bound at secondary sites are still transported. The homology modeling of human Pgp and substrate and modulator docking studies support the biochemical and transport data. In aggregate, our results demonstrate that a large flexible pocket in the Pgp transmembrane domains is able to bind chemically diverse compounds. When residues of the primary drug-binding site are mutated, substrates and modulators bind to secondary sites on the transporter and more than one transport-active binding site is available for each

  8. Multiple transport-active binding sites are available for a single substrate on human P-glycoprotein (ABCB1.

    Eduardo E Chufan

    Full Text Available P-glycoprotein (Pgp, ABCB1 is an ATP-Binding Cassette (ABC transporter that is associated with the development of multidrug resistance in cancer cells. Pgp transports a variety of chemically dissimilar amphipathic compounds using the energy from ATP hydrolysis. In the present study, to elucidate the binding sites on Pgp for substrates and modulators, we employed site-directed mutagenesis, cell- and membrane-based assays, molecular modeling and docking. We generated single, double and triple mutants with substitutions of the Y307, F343, Q725, F728, F978 and V982 residues at the proposed drug-binding site with cys in a cysless Pgp, and expressed them in insect and mammalian cells using a baculovirus expression system. All the mutant proteins were expressed at the cell surface to the same extent as the cysless wild-type Pgp. With substitution of three residues of the pocket (Y307, Q725 and V982 with cysteine in a cysless Pgp, QZ59S-SSS, cyclosporine A, tariquidar, valinomycin and FSBA lose the ability to inhibit the labeling of Pgp with a transport substrate, [(125I]-Iodoarylazidoprazosin, indicating these drugs cannot bind at their primary binding sites. However, the drugs can modulate the ATP hydrolysis of the mutant Pgps, demonstrating that they bind at secondary sites. In addition, the transport of six fluorescent substrates in HeLa cells expressing triple mutant (Y307C/Q725C/V982C Pgp is also not significantly altered, showing that substrates bound at secondary sites are still transported. The homology modeling of human Pgp and substrate and modulator docking studies support the biochemical and transport data. In aggregate, our results demonstrate that a large flexible pocket in the Pgp transmembrane domains is able to bind chemically diverse compounds. When residues of the primary drug-binding site are mutated, substrates and modulators bind to secondary sites on the transporter and more than one transport-active binding site is available

  9. The search for the mdr1-1Δ mutation of the MDR1 gene in four canine breeds in Uruguay (preliminary study)

    Rosa Gagliardi B.; Diana Martínez A.; Beatriz Tellechea H.; Pedro Sitjar Q.; Silvia Llambí D.; María Arruga L.

    2015-01-01

    Objective. The objective of this study is to analyze the frequency of mdr1-1Δ mutation in German Shepherd, Doberman, Border Collie and Greyhound dog breeds in Uruguay. Materials and methods. A total of 95 animals from the four breeds mentioned above were studied. DNA was isolated from blood using potassium acetate with a subsequent degradation from RNA with RNAsaH. The concentration and quality of the DNA obtained was evaluated with a Nanodrop, ND-1000 spectrophotometer. To determine the pres...

  10. PKCε inhibits isolation and stemness of side population cells via the suppression of ABCB1 transporter and PI3K/Akt, MAPK/ERK signaling in renal cell carcinoma cell line 769P.

    Huang, Bin; Fu, Shun Jun; Fan, Wen Zhe; Wang, Zhong Hua; Chen, Ze Bin; Guo, Sheng Jie; Chen, Jun Xing; Qiu, Shao Peng

    2016-06-28

    Protein kinase C epsilon (PKCε), a member of the novel PKC family, is known to be a transforming oncogene and tumor biomarker for many human solid cancers including renal cell carcinoma (RCC). We isolated side population (SP) cells from the RCC 769P cell line, and proved that those cells possess cancer stem cell (CSC) characteristics. In this study, to identify the function of PKCε in cancer stemness of 769P SP cells, we reduced the expression of PKCε in those cells, following the results demonstrated that PKCε depletion had a negative correlation with the existence of SP cells in 769P cell line. Down-regulation of PKCε also suppresses the CSC potential of sorted 769P SP cells in several ways: proliferation potential, resistance to chemotherapeutics and in vivo tumor formation ability. Our study also reveals that PKCε is associated with ABCB1 and this association probably contributed to the SP cells isolation from 769P cell line. Furthermore, the expression of ABCB1 is directly regulated by PKCε. Additionally, after the depletion of PKCε, the phosphorylation of pAkt, pStat3 and pERK was apparently suppressed in 769P SP cells, whereas PKCε overexpression could promote the phosphorylation of AKT, STAT3 and ERK in 769P Non-SP cells. Overall, PKCε down-regulation suppresses sorting and the cancer stem-like phenotype of RCC 769P SP cells through the regulation of ABCB1 transporter and the PI3K/Akt, Stat3 and MAPK/ERK pathways that are dependent on the phosphorylation effects. Thus, PKCε may work as an important mediator in cancer stem cell pathogenesis of renal cell cancer. PMID:27037060

  11. Frequency of the MDR1 mutant allele associated with multidrug sensitivity in dogs from Brazil

    Monobe MM

    2015-04-01

    Full Text Available Marina M Monobe,1 João P Araujo Junior,2 Kari V Lunsford,3 Rodrigo C Silva,4 Camilo Bulla41Department of Veterinary Clinics, School of Veterinary Medicine and Animal Science, 2Department of Microbiology and Immunology, Biosciences Institute, Sao Paulo State University (UNESP, Botucatu, Brazil; 3Department of Clinical Sciences and Animal Health Center, 4Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Mississippi, MS, USAAbstract: To date, a 4-bp deletion in the MDR1 gene has been detected in more than ten dog breeds, as well as in mixed breed dogs, in several countries, however information regarding this mutation in dogs from Brazil is lacking. For this reason, 103 Collies, 77 Border Collies, 76 Shetland Sheepdogs, 20 Old English Sheepdogs, 55 German Shepherds, 16 Australian Shepherds, and 53 Whippets from Brazil were screened for the presence of the mutation. The heterozygous mutated genotype, MDR1 (+/−, frequency found for Collies, Australian Shepherd, and Shetland Sheepdog was 50.5% (95% CI =41.1%–59.9%, 31.3% (95% CI =8.6%–53.2%, and 15.8% (95% CI =7.7%–23.9%, respectively. Homozygous mutated genotype, MDR1 (−/−, was detected only in Collies 35.9%. The MDR1 allele mutant frequency found for Collies, Australian Shepherd, and Shetland Sheepdog was 61.2% (95% CI =54.8%–67.5%, 15.6% (95% CI =3.1%–28.2%, and 7.9% (95% CI =3.7%–12.1%, respectively. Additionally, even free of the mutant allele, the maximum mutant prevalence (MMP in that population, with 95% CI, was 3.8%, 5.2%, 5.4%, and 13.8% for Border Collies, German Shepherds, Whippets, and Old English Sheepdogs, respectively. In this way, this information is important, not only for MDR1 genotype-based breeding programs and international exchange of breeding animals of predisposed breeds, but also for modification of drug therapy for breeds at risk.Keywords: P-glycoprotein, MDR1 mutation, ivermectin, dog, drug

  12. Reversing multidrug resistance in Caco-2 by silencing MDR1, MRP1, MRP2, and BCL-2/BCL-xL using liposomal antisense oligonucleotides.

    Yu-Li Lo

    Full Text Available Multidrug resistance (MDR is a major impediment to chemotherapy. In the present study, we designed antisense oligonucleotides (ASOs against MDR1, MDR-associated protein (MRP1, MRP2, and/or BCL-2/BCL-xL to reverse MDR transporters and induce apoptosis, respectively. The cationic liposomes (100 nm composed of N-[1-(2,3-dioleyloxypropyl]-n,n,n-trimethylammonium chloride and dioleoyl phosphotidylethanolamine core surrounded by a polyethylene glycol (PEG shell were prepared to carry ASOs and/or epirubicin, an antineoplastic agent. We aimed to simultaneously suppress efflux pumps, provoke apoptosis, and enhance the chemosensitivity of human colon adenocarcinoma Caco-2 cells to epirubicin. We evaluated encapsulation efficiency, particle size, cytotoxicity, intracellular accumulation, mRNA levels, cell cycle distribution, and caspase activity of these formulations. We found that PEGylated liposomal ASOs significantly reduced Caco-2 cell viability and thus intensified epirubicin-mediated apoptosis. These formulations also decreased the MDR1 promoter activity levels and enhanced the intracellular retention of epirubicin in Caco-2 cells. Epirubicin and ASOs in PEGylated liposomes remarkably decreased mRNA expression levels of human MDR1, MRP1, MRP2, and BCL-2. The combined treatments all significantly increased the mRNA expressions of p53 and BAX, and activity levels of caspase-3, -8, and -9. The formulation of epirubicin and ASOs targeting both pump resistance of MDR1, MRP1, and MRP2 and nonpump resistance of BCL-2/BCL-xL demonstrated more superior effect to all the other formulations used in this study. Our results provide a novel insight into the mechanisms by which PEGylated liposomal ASOs against both resistance types act as activators to epirubicin-induced apoptosis through suppressing MDR1, MRP1, and MRP2, as well as triggering intrinsic mitochondrial and extrinsic death receptor pathways. The complicated regulation of MDR highlights the necessity

  13. HIV-1 integrase inhibitors are substrates for the multidrug transporter MDR1-P-glycoprotein

    Cara Andrea; Andreotti Mauro; Galluzzo Clementina; Verdoliva Antonio; Costi Roberta; Molinari Agnese; Dupuis Maria; Cianfriglia Maurizio; Di Santo Roberto; Palmisano Lucia

    2007-01-01

    Abstract Background The discovery of diketoacid-containing derivatives as inhibitors of HIV-1 Integrase (IN) (IN inhibitors, IINs) has played a major role in validating this enzyme as an important target for antiretroviral therapy. Since the in vivo efficacy depends on access of these drugs to intracellular sites where HIV-1 replicates, we determined whether the IINs are recognized by the multidrug transporter MDR1-P-glycoprotein (P-gp) thereby reducing their intracellular accumulation. To ad...

  14. Multidrug-Resistant Transporter Mdr1p-Mediated Uptake of a Novel Antifungal Compound

    Sun, Nuo; Li, Dongmei; Fonzi, William; Xin LI; Zhang, Lixin; Calderone, Richard

    2013-01-01

    The activity of many anti-infectious drugs has been compromised by the evolution of multidrug-resistant (MDR) pathogens. For life-threatening fungal infections, such as those caused by Candida albicans, overexpression of MDR1, which encodes an MDR efflux pump of the major facilitator superfamily (MFS), often confers resistance to chemically unrelated substances, including the most commonly used azole antifungals. As the development of new and efficacious antifungals has lagged far behind the ...

  15. Association of Mdr1 Gene C1236t Polymorphism with Idiopathic Males’ Infertility in Guilan Population

    F Tajbakhsh

    2016-04-01

    Conclusion: The study findings revealed that a significant association was found between MDR1 polymorphism and idiopathic infertility (P= 0.001. Therefore, the results suggest that CT heterozygous genotype has a protective effect on male fertility (P= 0.01, OR= 0.41; 95%CI: 0.23- 0.84. However, to achieve more accurate results, it is necessary to examine a larger target population.

  16. Multidrug resistance mediated by a bacterial homolog of the human multidrug transporter MDR1.

    van Veen, Hendrik W.; Venema, Koen; Bolhuis, Henk; Oussenko, Irina; Kok, Jan; Poolman, Bert; Driessen, Arnold J. M.; Konings, Wil N.

    1996-01-01

    Resistance of Lactococcus lactis to cytotoxic compounds shares features with the multidrug resistance phenotype of mammalian tumor cells. Here, we report the gene cloning and functional characterization in Escherichia coli of LmrA, a lactococcal structural and functional homolog of the human multidrug resistance P-glycoprotein MDR1. LmrA is a 590-aa polypeptide that has a putative topology of six alpha-helical transmembrane segments in the N-terminal hydrophobic domain, followed by a hydrophi...

  17. Polymorphisms in DNA Repair Genes and MDR1 and the Risk for Non-Hodgkin Lymphoma

    Hee Nam Kim

    2014-04-01

    Full Text Available The damage caused by oxidative stress and exposure to cigarette smoke and alcohol necessitate DNA damage repair and transport by multidrug resistance-1 (MDR1. To explore the association between polymorphisms in these genes and non-Hodgkin lymphoma risk, we analyzed 15 polymorphisms of 12 genes in a population-based study in Korea (694 cases and 1700 controls. Four genotypes of DNA repair pathway genes (XRCC1 399 GA, OGG1 326 GG, BRCA1 871 TT, and WRN 787 TT were associated with a decreased risk for NHL [odds ratio (ORXRCC1 GA = 0.80, p = 0.02; OROGG1 GG = 0.70, p = 0.008; ORBRCA1 TT = 0.71, p = 0.048; ORWRN TT = 0.68, p = 0.01]. Conversely, the MGMT 115 CT genotype was associated with an increased risk for NHL (OR = 1.25, p = 0.04. In the MDR1 gene, the 1236 CC genotype was associated with a decreased risk for NHL (OR = 0.74, p = 0.04, and the 3435 CT and TT genotypes were associated with an increased risk (OR3435CT = 1.50, p < 0.0001; OR3435TT = 1.43, p = 0.02. These results suggest that polymorphisms in the DNA repair genes XRCC1, OGG1, BRCA1, WRN1, and MGMT and in the MDR1 gene may affect the risk for NHL in Korean patients.

  18. Development and characterization of P-glycoprotein 1 (Pgp1, ABCB1)-mediated doxorubicin-resistant PLHC-1 hepatoma fish cell line

    The development of the multidrug resistance (MDR) phenotype in mammals is often mediated by the overexpression of the P-glycoprotein1 (Pgp, ABCB1) or multidrug resistance-associated protein (MRP)-like ABC transport proteins. A similar phenomenon has also been observed and considered as an important part of the multixenobiotic resistance (MXR) defence system in aquatic organisms. We have recently demonstrated the presence of ABC transporters in the widely used in vitro fish model, the PLHC-1 hepatoma cell line. In the present study we were able to select a highly resistant PLHC-1 sub-clone (PLHC-1/dox) by culturing the wild-type cells in the presence of 1 μM doxorubicin. Using quantitative PCR a 42-fold higher expression of ABCB1 gene was determined in the PLHC-1/dox cells compared to non-selected wild-type cells (PLHC-1/wt). The efflux rates of model fluorescent Pgp1 substrates rhodamine 123 and calcein-AM were 3- to 4-fold higher in the PLHC-1/dox in comparison to the PLHC-1/wt cells. PLHC-1/dox were 45-fold more resistant to doxorubicin cytotoxicity than PLHC-1/wt. Similarly to mammalian cell lines, typical cross-resistance to cytotoxicity of other chemotherapeutics such as daunorubicin, vincristine, vinblastine, etoposide and colchicine, occurred. Furthermore, cyclosporine A, verapamil and PSC833, specific inhibitors of Pgp1 transport activity, completely reversed resistance of PLHC-1/dox cells to all tested drugs, resulting in EC50 values similar to the EC50 values found for PLHC-1/wt. In contrast, MK571, a specific inhibitor of MRP type of efflux transporters, sensitized PLHC-1/dox cells, neither to doxorubicin, nor to any other of the chemotherapeutics used in the study. These data demonstrate for the first time that a specific Pgp1-mediated doxorubicin resistance mechanism is present in the PLHC-1 fish hepatoma cell line. In addition, the fact that low micromolar concentrations of specific inhibitors may completely reverse a highly expressed doxorubicin

  19. Differential Requirement of the Transcription Factor Mcm1 for Activation of the Candida albicans Multidrug Efflux Pump MDR1 by Its Regulators Mrr1 and Cap1▿

    Mogavero, Selene; Tavanti, Arianna; Senesi, Sonia; Rogers, P. David; Morschhäuser, Joachim

    2011-01-01

    Overexpression of the multidrug efflux pump Mdr1 causes increased fluconazole resistance in the pathogenic yeast Candida albicans. The transcription factors Mrr1 and Cap1 mediate MDR1 upregulation in response to inducing stimuli, and gain-of-function mutations in Mrr1 or Cap1, which render the transcription factors hyperactive, result in constitutive MDR1 overexpression. The essential MADS box transcription factor Mcm1 also binds to the MDR1 promoter, but its role in inducible or constitutive...

  20. Role of ABCB1, ABCG2, ABCC2 and ABCC5 transporters in placental passage of zidovudine.

    Neumanova, Zuzana; Cerveny, Lukas; Ceckova, Martina; Staud, Frantisek

    2016-01-01

    Zidovudine (AZT) is one of the most frequently used antiretroviral drugs in prevention of perinatal transmission of HIV. However, safety concerns on AZT use in pregnancy still persist as severe side effects are associated with AZT exposure in children. In our study we aimed to contribute to current knowledge on AZT transplacental transport and to evaluate potential involvement of the main human drug efflux ATP-binding cassette (ABC) transporters, p-glycoprotein (ABCB1), breast cancer resistance protein (ABCG2) and multidrug resistance-associated proteins 2 and 5 (ABCC2 and ABCC5) in the disposition of AZT between mother and fetus. In order to elucidate this issue we investigated the effect of selected ABC transporters on AZT transepithelial transport across MDCKII cell monolayers. In addition we used the in situ method of dually perfused rat term placenta to further study the role of ABC transporters in AZT transplacental transport. In vitro studies revealed significant effect of ABCB1 and ABCG2 on AZT transport which was subsequently confirmed also on organ level. Lamivudine, an antiretroviral agent commonly co-administered with AZT, did not affect ABC transporter-mediated AZT transfer. Copyright © 2016 John Wiley & Sons, Ltd. PMID:26390406

  1. 血清标志物(NSE、CEA、CA-125、CYFRA21-1)和分子标志物(MDR-1、LRP、RRM-1、EGFR、ERCC-1、BRCA-1)在非小细胞肺癌患者原发灶和转移淋巴结的表达%Expression of serum markers (NSE,CEA, CA-125,CYFRA 21-1)and molecular mark-ers (MDR-1,LRP,RRM-1,EGFR,ERCC-1,BRCA-1)in primary sites and metastatic lymph nodes of lung cancer patients

    郭楠楠; 李珊珊; 张文; 于长海; 俞建琦; 李少军

    2014-01-01

    AIM:To investigate the different expressions of ser-um markers and molecular markers in the primary tumor and the metastatic lymph nodes of lung cancer patients with four histologi-cal subtypes.METHODS:There were 48 cases of lung cancer patients who underwent thoracic surgery for removal of primary and metastatic lesions had been enrolled for testing.RESULTS:Expression of ERCC-1 was significantly different in primary tumors and metastatic sites (P=0.007 )and the serum level of CEA was significantly different for patients with different cancer subtypes (P =0.008 ). CONCLUSION:Tumor molecular markers have value to estimate prognosis and select treatments for patients.%目的:研究不同血清标志物及分子标志物在肺癌不同病理亚型、原发灶与转移淋巴结间表达的差异.方法:对48例住院接受开胸手术切除原发病灶及转移淋巴结的患者进行4种血清标志物和6种分子标记物检测.结果:ERCC-1的表达在原发肿瘤和转移部位间有显著差异(P=0.007);CEA的血清水平在不同肿瘤亚型患者间存在显著差异(P=0.008).结论:标志物检测对于患者预后的判断及治疗方案具有一定价值.

  2. Impact of BCRP/MXR, MRP1 and MDR1/P-Glycoprotein on thermoresistant variants of atypical and classical multidrug resistant cancer cells

    Stein, Ulrike; Lage, Hermann; Jordan, Andreas;

    2002-01-01

    The impact of the ABC transporters breast cancer resistance protein/mitoxantrone resistance associated transporter (BCRP/MXR), multidrug resistance-associated protein 1 (MRP1) and multidrug resistance gene-1/P-glycoprotein (MDR1/PGP) on the multidrug resistance (MDR) phenotype in chemoresistance...... and thermoresistance was investigated in the parental human gastric carcinoma cell line EPG85-257P, the atypical MDR subline EPG85-257RNOV, the classical MDR subline EPG85-257RDB and their thermoresistant counterparts EPG85-257P-TR, EPG85-257RNOV-TR and EPG85-257RDB-TR. Within the atypical MDR subline...... EPG85-257RNOV expression of BCRP/MXR and of MRP1 were clearly enhanced (vs. parental and classical MDR lines). MDR1/PGP expression was distinctly elevated in the classical MDR subline EPG85-257RDB (vs. parental and atypical MDR sublines). In all thermoresistant counterparts basal expression of BCRP...

  3. ABCB1 and ABCC2 and the risk of distant metastasis in Thai breast cancer patients treated with tamoxifen

    Sensorn I

    2016-04-01

    Full Text Available Insee Sensorn,1,* Chonlaphat Sukasem,2,* Ekaphop Sirachainan,3 Montri Chamnanphon,2 Ekawat Pasomsub,4 Narumol Trachu,5 Porntip Supavilai,1 Darawan Pinthong,1 Sansanee Wongwaisayawan6 1Department of Pharmacology, Faculty of Science, Mahidol University, 2Division of Pharmacogenomics and Personalized Medicine, Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, 3Division of Medical Oncology, Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, 4Division of Virology, Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, 5Research Center, Faculty of Medicine, Ramathibodi Hospital, 6Division of Anatomical Pathology, Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand *These authors contributed equally to this work Background: Genetic polymorphisms of drug-metabolizing enzymes and transporters have been extensively studied with regard to tamoxifen treatment outcomes. However, the results are inconclusive. Analysis of organ-specific metastasis may reveal the association of these pharmacogenetic factors. The aim of this study is to investigate the impact of CYP3A5, CYP2D6, ABCB1, and ABCC2 polymorphisms on the risk of all distant and organ-specific metastases in Thai patients who received tamoxifen adjuvant therapy. Methods: Genomic DNA was extracted from blood samples of 73 patients with breast cancer who received tamoxifen adjuvant therapy. CYP3A5 (6986A>G, CYP2D6 (100C>T, ABCB1 (3435C>T, and ABCC2 (-24C>T were genotyped using allelic discrimination real-time polymerase chain reaction assays. The impacts of prognostic clinical factors and genetic variants on disease-free survival were analyzed using the Kaplan–Meier method and Cox regression analysis. Results: In the univariate analysis, primary tumor size >5 cm was significantly associated with increased risk of distant metastasis (P=0

  4. Cloning and molecular characterization of apical efflux transporters (ABCB1, ABCB11 and ABCC2) in rainbow trout (Oncorhynchus mykiss) hepatocytes.

    Zaja, Roko; Munić, Vesna; Klobucar, Roberta Sauerborn; Ambriović-Ristov, Andreja; Smital, Tvrtko

    2008-12-11

    Fish possess similar mechanisms of billiary excretion of xeno(endo)biotics and their metabolites as found in higher vertebrates and various types of ABC efflux proteins expressed in apical membranes of polarized cells appears to be key mediators of this vectorial transport. To test this hypothesis the main goals of this study were identification and cloning of genes coding for different types of ABC transport proteins, determination of the gene transcript (mRNA) levels, and characterization of the related protein transport activities in primary cultured rainbow trout (Oncorhynchus mykiss) hepatocytes. We have cloned one partial and two full gene sequences, which show high degree of identity with mammalian Pgp1 (ABCB1), BSEP (ABCB11) and MRP2 (ABCC2) efflux transporters. Using real-time RT-PCR expression levels of the mRNA of these genes were determined. Identical relative expression patterns of identified efflux transporters (BSEP>MRP2>Pgp1) were observed for both liver and primary hepatocytes, with expression of all three transporter mRNAs approximately 3-4-fold lower in primary hepatocytes in comparison to intact liver. In addition, the presence of Pgp1-, BSEP- and MRP-like transport activities were indicated using putative specific fluorescent substrates (rhodamine 123, calcein-AM, bodipy-verapamil and dihydrofluorescein diacetat), model inhibitors (verapamil, cyclosporine A, MK571, reversine 205, taurocholate and taurochenodeoxycholate) and their combinations. Taken together the results of this study showed that primary trout hepatocytes express critical components of detoxification pathways-phase I and II enzymes, as well as the ABC proteins involved in transport of xenobiotics, affirming this in vitro model as a promising tool in (eco)toxicological research. PMID:19008001

  5. 沉默MDR1基因增强急性早幼粒白血病耐药细胞HT9药物敏感性%Effect of RNAi Silencing MDR1 Gene on the Sensitivity of Multidrug Resistant Actue Promyelocytic Leukemia Cells HT9 to Drugs

    邵淑丽; 李旭艳; 张伟伟; 恽东泽; 付博; 张珍珠

    2012-01-01

    该研究利用短发卡RNA(small hairpin RNA,shRNA)表达载体沉默HT9急性早幼粒白血病耐药细胞MDR1基因表达,以提高细胞对三尖杉酯碱、阿霉素的敏感性.通过设计合成编码shRNA的DNA模板序列,定向克隆到pSilencer 2.1-U6 neo质粒,成功构建1个P-gp蛋白基因特异的shRNA表达载体,稳定电转染HT9细胞,实时荧光定量PCR分析MDR1 mRNA表达,Western blot检测细胞P-gp蛋白表达,流式细胞术检测P-gp蛋白外排泵功能,MTT法检测细胞对药物敏感性.结果显示,成功构建了shRNA表达载体pSilencer2.1-U6 neo-MDR1,转染HT9细胞后,PCR检测重组质粒整合到HT9/sh-2.1-1细胞基因组DNA,获得稳定遗传;HT9/sh-2.1-1细胞MDR1mRNA达降低了78.84%(P<0.01),P-gp蛋白表达降低了48.27%(P<0.05),细胞内Rho123相对荧光强度由(10.8±0.58)%升高至(73.56士1.37)%;转染细胞对三尖杉酯碱、阿霉素敏感性明显增强,IC50分别由(2.06±0.15) μmol/L降至(0.57±0.01) μmol/L、(4.04士017) μmol/L降至(1.56±0.05) μmol/L.提示shRNA干扰表达载体pSilencer2.1-U6 neo-MDR1能够稳定、持久地抑制MDR1基因表达,并能有效增强HT9细胞对三尖杉酯碱、阿霉素的敏感性.%The study investigated the effects of RNAi silencing MDR1 gene, increase the sensitivity of multidrug resistant actue promyelocytic leukemia cells HT9 to harringtonine and doxorubicin. One short hairpin RNA (small hairpin RNA, shRNA) was designed and constructed into pSilencer2.1-U6 neo plasmid. MDR1 shRNA expression plasmid pSilencer 2.1-U6 neo-MDRl was constructed and introduced into HT9 cells. MDR1 mRNA was assayed by real-time fluorescent quantitative PCR. The P-gp protein was assayed by Western blot. The pump function of P-gp was assayed by FCM. The sensitivity of cells to drugs were assayed by MTT. The results suggested that pSilencer 2.1-U6 neo-MDRl expression plasmid was constructed successfully. The results of PCR showed that the shRNA recombinant plasmid

  6. Prvi dokaz ekspresije gena za P-glikoprotein (P-gp/ABCB1) i djelovanja inhibitora na multiksenobiotičku otpornost u gujavice

    Bošnjak, Ivana; Bielen, Ana; Babić, Sanja; ŠVER, LIDIJA; Topić Popović, Natalija; Strunjak-Perović, Ivančica; Čož-Rakovac, Rozelinda; Sauerborn Klobučar, Roberta

    2014-01-01

    Mehanizam multiksenobiotičke otpornosti (MXR) prisutan je u mnogim organizmima kao važan stanični detoksikacijski mehanizam. Posredovan je aktivnošću ABC prijenosnika koji vežu i aktivno izbacuju različite toksične tvari iz stanice. U ovom radu dani su podaci o molekularnoj identifikaciji ABC prijenosnika (eksportera) - P-glikoproteina (P-gp/Abcb1), kao jednog od predstavnika MXR fenotipa, u gujavici Eisenia fetida. Određen je djelomični slijed identificiranoga gena Abcb1, njegov predviđeni a...

  7. Zosuquidar restores drug sensitivity in P-glycoprotein expressing acute myeloid leukemia (AML)

    Chemotherapeutic drug efflux via the P-glycoprotein (P-gp) transporter encoded by the MDR1/ABCB1 gene is a significant cause of drug resistance in numerous malignancies, including acute leukemias, especially in older patients with acute myeloid leukemia (AML). Therefore, the P-gp modulators that block P-gp-mediated drug efflux have been developed, and used in combination with standard chemotherapy. In this paper, the capacity of zosuquidar, a specific P-gp modulator, to reverse chemoresistance was examined in both leukemia cell lines and primary AML blasts. The transporter protein expressions were analyzed by flow cytometry using their specific antibodies. The protein functionalities were assessed by the uptake of their fluorescence substrates in presence or absence their specific modulators. The drug cytotoxicity was evaluated by MTT test. Zosuquidar completely or partially restored drug sensitivity in all P-gp-expressing leukemia cell lines tested and enhanced the cytotoxicity of anthracyclines (daunorubicin, idarubicin, mitoxantrone) and gemtuzumab ozogamicin (Mylotarg) in primary AML blasts with active P-gp. In addition, P-gp inhibition by zosuquidar was found to be more potent than cyclosporine A in cells with highly active P-gp. These in vitro studies suggest that zosuquidar may be an effective adjunct to cytotoxic chemotherapy for AML patients whose blasts express P-gp, especially for older patients

  8. Functional analysis of chimeric genes obtained by exchanging homologous domains of the mouse mdr1 and mdr2 genes.

    Buschman, E; Gros, P.

    1991-01-01

    A full-length cDNA clone for the mouse mdr1 gene can confer multidrug resistance when introduced by transfection into otherwise drug-sensitive cells. In the same assay, a full-length cDNA clone for a closely related member of the mouse mdr gene family, mdr2, fails to confer multidrug resistance. To identify the domains of mdr1 which are essential for multidrug resistance and which may be functionally distinct in mdr2, we have constructed chimeric cDNA molecules in which discrete domains of md...

  9. Associations of ABCB1, NFKB1, CYP3A, and NR1I2 polymorphisms with cyclosporine trough concentrations in Chinese renal transplant recipients

    Yu ZHANG; Jia-li LI; Qian FU; Xue-ding WANG; Long-shan LIU; Chang-xi WANG; Wen XIE

    2013-01-01

    Aim:Cyclosporine requires close therapeutic drug monitoring because of its narrow therapeutic index and marked inter-individual pharmacokinetic variation.In this study,we investigated the associations of CYP3A4,CYP3A5,ABCB1,NFKB1,and NR1I2 polymorphisms with cyclosporine concentrations in Chinese renal transplant recipients in the early period after renal transplantation.Methods:A total of 101 renal transplant recipients receiving cyclosporine were genotyped for CYP3A4*1G,CYP3A5*3,ABCB1 C1236T,G2677T/A,C3435T,NFKB1-94 ins/del ATTG,and NR1I2 polymorphisms.Cyclosporine whole blood levels were measured by a fluorescence polarization immunoassay.Trough concentrations of cyclosporine were determined for days 7-18 following transplantation.Results:The dose-adjusted trough concentration (C0) of cyclosporine in ABCB1 2677 TT carriers was significantly higher than that in GG carriers together with GT carriers [90.4±24.5 vs 67.8±26.8 (ng/mL)/(mg/kg),P=0.001].ABCB1 3435 TT carriers had a significantly higher dose-adjusted C0 of cyclosporine than CC carriers together with CT carriers [92.0±24.0 vs 68.4±26.5 (ng/mL)/(mg/kg),P=0.002].Carriers of the ABCB1 1236TT-2677TT-3435TT haplotype had a considerably higher CsA C0/D than carriers of other genotypes [97.2±21.8 vs 68.7±26.9 (ng/mL)/(mg/kg),P=0.001].Among non-carriers of the ABCB1 2677 TT and 3435 TT genotypes,patients with the NFKB1-94 ATTG ins/ins genotype had a significantly higher dose-adjusted C0 than those with the-94 ATTG del/del genotype [75.9±32.9 vs 55.1±15.1 (ng/mL)/(mg/kg),P=0.026].Conclusion:These results illustrate that the ABCB1 and NFKB1 genotypes are closely correlated with cyclosporine trough concentrations,suggesting that these SNPs are useful for determining the appropriate dose of cyclosporine.

  10. Association of CYP3A4/5, ABCB1 and ABCC2 polymorphisms and clinical outcomes of Thai breast cancer patients treated with tamoxifen

    Sensorn I

    2013-08-01

    Full Text Available Insee Sensorn,1 Ekaphop Sirachainan,2 Montri Chamnanphon,3 Ekawat Pasomsub,4 Narumol Trachu,5 Porntip Supavilai,1 Chonlaphat Sukasem,3 Darawan Pinthong11Department of Pharmacology, Faculty of Science, Mahidol University, Bangkok, Thailand; 2Division of Medical Oncology, Department of Medicine, 3Division for Pharmacogenomics and Personalized Medicine, 4Division for Virology, Department of Pathology, 5Research Center, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, ThailandBackground: Pharmacogenetic study of cytochrome P450 (CYP gene CYP2D6 and tamoxifen outcomes remain controversial. Apart from CYP2D6, other drug-metabolizing enzymes and transporters also play a role in tamoxifen metabolic pathways. The aim of this study is to investigate the impact of CYP3A4/5, ABCB1, and ABCC2 polymorphisms on the risk of recurrence in Thai patients who received tamoxifen adjuvant therapy.Methods: Patients with early-stage breast cancer who received tamoxifen adjuvant therapy were recruited in this study. All six single-nucleotide polymorphisms (SNPs, including CYP3A4*1B (-392 A>G/*18(878 T>C, CYP3A5*3(6986 G>A, ABCB1 3435 C>T, ABCC2*1C (-24 C>T, and ABCC2 68231 A>G, were genotyped using real-time polymerase chain reaction assays. The impacts of genetic variants on disease-free survival (DFS were analyzed using the Kaplan–Meier method and Cox regression analysis.Results: The ABCB1 3435 C>T was found to have the highest allele frequency among other variants; however, CYP3A4*1B/*18 could not be found in this study. Patients with heterozygous ABCB1 3435 CT genotype showed significantly shorter DFS than those with homozygous 3435 CC genotype (P = 0.041. In contrast, patients who carried homozygous 3435 TT genotype showed no difference in DFS from wild-type 3435 CC patients. Cox regression analysis showed that the relative risk of recurrence was increased by five times (P = 0.043; hazard ratio = 5.11; 95% confidence interval: 1.05–24

  11. Mutace genu v MDR1 u psů ve vztahu k citlivosti na léčiva

    Patermannová, Veronika

    2014-01-01

    This work deals with the multidrug resistance gene (MDR1), its structure, function, localization on dog's genome and especially its dysfunction in case of mutation. Work gives information about heredity of mutated alleles MDR1 gene, detection mutation using polymerase chain reaction (PCR). Information are written as a literature review and were drawn from scholarly articles. On base these articles was created summary of frequency all genotypes MDR1 gene in dogs in Czech Republic and foreign c...

  12. The value of the MDR1 reversal agent PSC-833 in addition to daunorubicin and cytarabine in the treatment of elderly patients with previously untreated acute myeloid leukemia (AML), in relation to MDR1 status at diagnosis

    van der Holt, B; Lowenberg, B; Burnett, AK; Knauf, WU; Shepherd, J; Piccaluga, PP; Ossenkoppele, GJ; Verhoef, GEG; Ferrant, A; Crump, M; Selleslag, D; Theobald, M; Fey, MF; Vellenga, E; Dugan, M; Sonneveld, P

    2005-01-01

    To determine whether MDR1 reversal by the addition of the P-glycoprotein (P-gp) inhibitor PSC-833 to standard induction chemotherapy would improve event-free survival (EFS), 419 untreated patients with acute myeloid leukemia (AML) aged 60 years and older were randomized to receive 2 induction cycles

  13. Heterologously expressed bacterial and human multidrug resistance proteins confer cadmium resistance to Escherichia coli

    Achard-Joris, M; van Saparoea, HBV; Driessen, AJM; Bourdineaud, JP; Bourdineaud, Jean-Paul

    2005-01-01

    The human MDR1 gene is induced by cadmium exposure although no resistance to this metal is observed in human cells overexpressing hMDR1. To access the role of MDR proteins in cadmium resistance, human MDR1, Lactococcus lactis lmrA, and Oenococcus oeni omrA were expressed in an Escherichia coli tolC

  14. Genetic association analysis of ATP binding cassette protein family reveals a novel association of ABCB1 genetic variants with epilepsy risk, but not with drug-resistance.

    Shabeesh Balan

    Full Text Available Epilepsy constitutes a heterogeneous group of disorders that is characterized by recurrent unprovoked seizures due to widely different etiologies. Multidrug resistance remains a major issue in clinical epileptology, where one third of patients with epilepsy continue to have seizures. Role of efflux transporters in multidrug resistant epilepsy has been attributed to drug-resistant epilepsy although, with discrepant observation in genetic studies. These discrepancies could be attributed to variety of factors such as variable definition of the anti-epileptic drug (AED-resistance, variable epilepsy phenotypes and ethnicities among the studies. In the present study we inquired the role of multidrug transporters ABCB1 and ABCG2 variants in determining AED-resistance and susceptibility to epilepsy in three well-characterized cohorts comprising of mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS (prototype for AED-resistant epilepsy; juvenile myoclonic epilepsy (JME (prototype for AED-responsive epilepsy; and healthy non-epileptic controls, in 738 subjects of Malayalam speaking south Indian ancestry. ABCB1 and ABCG2 variants were not found to be associated with drug resistance when AED-resistant and AED-responsive cohorts were compared. However, a significant association was observed between ABCB1 (C3435T rs1045642 and risk of having epilepsy (MTLE-HS and JME pooled cohort; genotypic p-value = 0.0002; allelic p-value = 0.004. This association was seen persistent with MTLE-HS (genotypic p-value = 0.0008; allelic p-value = 0.004 and also with JME (genotypic p-value = 0.01; allelic p-value = 0.05 cohort individually. In-silico functional prediction indicated that ABCB1 rs1045642 has a deleterious impact on protein coding function and in splicing regulation. We conclude that the ABCB1 and ABCG2 variants do not confer to AED-resistance in the study population. However, ABCB1 rs1045642 increases vulnerability to epilepsy with greater tendency

  15. Genetic association analysis of ATP binding cassette protein family reveals a novel association of ABCB1 genetic variants with epilepsy risk, but not with drug-resistance.

    Balan, Shabeesh; Bharathan, Sumitha Prameela; Vellichiramal, Neetha Nanoth; Sathyan, Sanish; Joseph, Vijai; Radhakrishnan, Kurupath; Banerjee, Moinak

    2014-01-01

    Epilepsy constitutes a heterogeneous group of disorders that is characterized by recurrent unprovoked seizures due to widely different etiologies. Multidrug resistance remains a major issue in clinical epileptology, where one third of patients with epilepsy continue to have seizures. Role of efflux transporters in multidrug resistant epilepsy has been attributed to drug-resistant epilepsy although, with discrepant observation in genetic studies. These discrepancies could be attributed to variety of factors such as variable definition of the anti-epileptic drug (AED)-resistance, variable epilepsy phenotypes and ethnicities among the studies. In the present study we inquired the role of multidrug transporters ABCB1 and ABCG2 variants in determining AED-resistance and susceptibility to epilepsy in three well-characterized cohorts comprising of mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) (prototype for AED-resistant epilepsy); juvenile myoclonic epilepsy (JME) (prototype for AED-responsive epilepsy); and healthy non-epileptic controls, in 738 subjects of Malayalam speaking south Indian ancestry. ABCB1 and ABCG2 variants were not found to be associated with drug resistance when AED-resistant and AED-responsive cohorts were compared. However, a significant association was observed between ABCB1 (C3435T) rs1045642 and risk of having epilepsy (MTLE-HS and JME pooled cohort; genotypic p-value = 0.0002; allelic p-value = 0.004). This association was seen persistent with MTLE-HS (genotypic p-value = 0.0008; allelic p-value = 0.004) and also with JME (genotypic p-value = 0.01; allelic p-value = 0.05) cohort individually. In-silico functional prediction indicated that ABCB1 rs1045642 has a deleterious impact on protein coding function and in splicing regulation. We conclude that the ABCB1 and ABCG2 variants do not confer to AED-resistance in the study population. However, ABCB1 rs1045642 increases vulnerability to epilepsy with greater tendency for MTLE

  16. Genetic Association Analysis of ATP Binding Cassette Protein Family Reveals a Novel Association of ABCB1 Genetic Variants with Epilepsy Risk, but Not with Drug-Resistance

    Balan, Shabeesh; Bharathan, Sumitha Prameela; Vellichiramal, Neetha Nanoth; Sathyan, Sanish; Joseph, Vijai; Radhakrishnan, Kurupath; Banerjee, Moinak

    2014-01-01

    Epilepsy constitutes a heterogeneous group of disorders that is characterized by recurrent unprovoked seizures due to widely different etiologies. Multidrug resistance remains a major issue in clinical epileptology, where one third of patients with epilepsy continue to have seizures. Role of efflux transporters in multidrug resistant epilepsy has been attributed to drug-resistant epilepsy although, with discrepant observation in genetic studies. These discrepancies could be attributed to variety of factors such as variable definition of the anti-epileptic drug (AED)-resistance, variable epilepsy phenotypes and ethnicities among the studies. In the present study we inquired the role of multidrug transporters ABCB1 and ABCG2 variants in determining AED-resistance and susceptibility to epilepsy in three well-characterized cohorts comprising of mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) (prototype for AED-resistant epilepsy); juvenile myoclonic epilepsy (JME) (prototype for AED-responsive epilepsy); and healthy non-epileptic controls, in 738 subjects of Malayalam speaking south Indian ancestry. ABCB1 and ABCG2 variants were not found to be associated with drug resistance when AED-resistant and AED-responsive cohorts were compared. However, a significant association was observed between ABCB1 (C3435T) rs1045642 and risk of having epilepsy (MTLE-HS and JME pooled cohort; genotypic p-value = 0.0002; allelic p-value = 0.004). This association was seen persistent with MTLE-HS (genotypic p-value = 0.0008; allelic p-value = 0.004) and also with JME (genotypic p-value = 0.01; allelic p-value = 0.05) cohort individually. In-silico functional prediction indicated that ABCB1 rs1045642 has a deleterious impact on protein coding function and in splicing regulation. We conclude that the ABCB1 and ABCG2 variants do not confer to AED-resistance in the study population. However, ABCB1 rs1045642 increases vulnerability to epilepsy with

  17. 药物基因组学相关P450和ABCB1多态性及SNP检测技术%Pharmacogenomics-related P450 and ABCB1 Polymorphisms and SNP Detection Technology

    眭维国; 张若菡; 陈洁晶; 戴勇

    2011-01-01

    药物基因组学(phamacogenomics)是临床检测遗传差异引起药物应答个体性差异的学科,它涉及药物代谢和有害的药物反应的预测等方面的内容.个性化药物和个性化治疗发展的关键条件是能够快速简便的检测出病人的遗传多态性.文章综述了药物基因相关问题,细胞色素酶P450和ABCB1转运蛋白的遗传多态性以及检测遗传多态性的相关技术.%Pharmacogenomics is the study of the influence of genetic factors on drug action. It is increasingly important for predicting metabolism and adverse reaction to drugs. A key requirement for the development of individualized medicine or personalized therapy is the ability to rapidly and conveniently test the genetic polymorphisms and mutations in patients. This review addresses the social issues in Pharmacogenomics testing, the cytochrome P450, human ACBC1 genetic polymorphismand some new methods for single nucleotide polymorphism ( SNP ) detection.

  18. SNP genetic polymorphisms of MDR-1, CYP1A2 and CYPB11 genes in four canine breeds upon toxicological evaluation.

    Gagliardi, Rosa; Llambí, Silvia; Arruga, M Victoria

    2015-01-01

    The fields of pharmacogenetics and pharmacogenomics have become increasingly promising regarding the clinical application of genetic data to aid in prevention of adverse reactions. Specific screening tests can predict which animals express modified proteins or genetic sequences responsible for adverse effects associated with a drug. Among the genetic variations that have been investigated in dogs, the multidrug resistance gene (MDR) is the best studied. However, other genes such as CYP1A2 and CYP2B11 control the protein syntheses involved in the metabolism of many drugs. In the present study, the MDR-1, CYP1A2 and CYP2B11 genes were examined to identify SNP polymorphisms associated with these genes in the following four canine breeds: Uruguayan Cimarron, Border Collie, Labrador Retriever and German Shepherd. The results revealed that several SNPs of the CYP1A2 and CYP2B11 genes are potential targets for drug sensitivity investigations. PMID:25797294

  19. Expression of P-glycoprotein in excised human nasal mucosa and optimized models of RPMI 2650 cells.

    Dolberg, Anne M; Reichl, Stephan

    2016-07-11

    To assess the transmucosal drug transport in the development of medications for intranasal administration, cellular in vitro models are preferred over the use of animal tissues due to inter-species variations and ethical concerns. With regard to the distribution of active agents and multidrug resistance, the ABC transporter P-glycoprotein plays a major role in several mammalian tissues. The present study compares the expression of this efflux pump in optimized in vitro models based on the human RPMI 2650 cell line with specimens of human turbinate mucosa. The presence of the ABCB1 gene was investigated at the mRNA and protein levels using RT-PCR and Western blot analysis in differently cultured RPMI 2650 cells and excised human nasal epithelium. Furthermore, the localization and activity of P-gp was examined by immunohistochemical staining and functionality assays using different substrates in both in vitro and ex vivo models. Both mRNA and protein expression of P-gp was found in all studied models. Furthermore, transporter functionality was detected in both RPMI 2650 cell culture models and excised human mucosa. The results demonstrated a highly promising comparability between RPMI 2650 models and explants of human nasal tissue concerning the influence of MDR1 on drug disposition. The RPMI 2650 cell line might become a useful tool in preclinical trials to improve reproducibility and achieve greater applicability to humans of experimental data regarding passive diffusion and active efflux of drug candidates. PMID:27155589

  20. A pharmacogenetic study of ABCB1 polymorphisms and cyclosporine treatment response in patients with psoriasis in the Greek population.

    Vasilopoulos, Y; Sarri, C; Zafiriou, E; Patsatsi, A; Stamatis, C; Ntoumou, E; Fassos, I; Tsalta, A; Karra, A; Roussaki-Schulze, A; Sotiriadis, D; Mamuris, Z; Sarafidou, T

    2014-12-01

    Psoriasis affects 2-3% of the population, causing significant morbidity and financial burden. Immunosuppressive drugs such as cyclosporine are first line systemic therapies for moderate-to-severe forms. However, patients exhibit heterogeneity in their response to therapy, possibly due to genetic factors. The aim of the present study was to assess the ABCB1 T-129C, G1199A, C1236T, G2677T and C3435T single-nucleotide polymorphisms (SNPs) as candidate predictive markers of response to cyclosporine treatment in 84 psoriasis patients. 62% of the patients were defined as responders and 38% as nonresponders. All SNPs complied with Hardy-Weinberg equilibrium. SNP and haplotype analyses were performed to access responsiveness to treatment. Association analysis revealed statistically significant association of SNP 3435 T with negative response (P=0.0075), a result that was further validated in haplotype analysis. This study is the first in the field of the pharmacogenetics of cyclosporine in psoriasis whose results merit further exploitation in larger independent cohorts. PMID:24889923

  1. HG-829 is a potent noncompetitive inhibitor of the ATP-binding cassette multidrug resistance transporter ABCB1.

    Caceres, Gisela; Robey, Robert W; Sokol, Lubomir; McGraw, Kathy L; Clark, Justine; Lawrence, Nicholas J; Sebti, Said M; Wiese, Michael; List, Alan F

    2012-08-15

    Transmembrane drug export mediated by the ATP-binding cassette (ABC) transporter P-glycoprotein contributes to clinical resistance to antineoplastics. In this study, we identified the substituted quinoline HG-829 as a novel, noncompetitive, and potent P-glycoprotein inhibitor that overcomes in vitro and in vivo drug resistance. We found that nontoxic concentrations of HG-829 restored sensitivity to P-glycoprotein oncolytic substrates. In ABCB1-overexpressing cell lines, HG-829 significantly enhanced cytotoxicity to daunorubicin, paclitaxel, vinblastine, vincristine, and etoposide. Coadministration of HG-829 fully restored in vivo antitumor activity of daunorubicin in mice without added toxicity. Functional assays showed that HG-829 is not a Pgp substrate or competitive inhibitor of Pgp-mediated drug efflux but rather acts as a noncompetitive modulator of P-glycoprotein transport function. Taken together, our findings indicate that HG-829 is a potent, long-acting, and noncompetitive modulator of P-glycoprotein export function that may offer therapeutic promise for multidrug-resistant malignancies. PMID:22761337

  2. Different frequencies and effects of ABCB1 T3435C polymorphism on clinical and laboratory features of B cell chronic lymphocytic leukemia in Kurdish patients.

    Maroofi, Farzad; Amini, Sabrieh; Roshani, Daem; Ghaderi, Bayazid; Abdi, Mohammad

    2015-04-01

    Finding the effects of gene polymorphism on cancer pathogenesis is very desirable. The ATP-binding cassette is involved in drug metabolism, and the polymorphism of this gene may be an important risk factor in B cell chronic lymphocytic leukemia (B-CLL) or progression and/or response to chemotherapy agents. For the first time, the present study was aimed to evaluate the probable effects of ABCB1 T3435C polymorphism on clinical and laboratory features of Kurdish patients with B-CLL. This descriptive analytical case-control study was performed on 50 B-CLL patients and 100 healthy subjects. Serum levels of beta-2-microglobulin (B2M) and lactate dehydrogenase (LDH) and blood WBC, RBC, Plt and ESR were measured. The T3435C polymorphism of the ABCB1 gene was determined by PCR-RFLP. Concentration of serum and blood markers was significantly higher in the malignant group than in the benign subjects. The CC genotype had the highest frequency (66%) in the patient groups. There are no significant differences between the genotypes and type of treatment. Our results demonstrate the high frequency of C allele of ABCB1 T3435C in B-CLL patients with Kurdish ethnicity. We also show that this polymorphism has a significant risk factor in B-CLL. However, the effect of this polymorphism on clinical and laboratory characteristics of B-CLL patients was not significant. PMID:25586345

  3. Association of MDR1 gene polymorphisms with the risk of hepatocellular carcinoma in the Chinese Han population

    The multidrug resistance 1 gene (MDR1) is an important candidate gene for influencing susceptibility to hepatocellular carcinoma (HCC). The objective of the present study was to evaluate the association of MDR1 polymorphisms with the risk of HCC in the Chinese Han population. A total of 353 HCC patients and 335 healthy subjects were enrolled in the study. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), created restriction site-PCR (CRS-PCR) and DNA sequencing methods were used to identify MDR1 gene polymorphisms. Two allelic variants (c.335T>C and c.3073A>C) were detected. The CC genotype of the c.335T>C polymorphism was associated with an increased risk of developing HCC compared to the TT genotype (OR = 2.161, 95%CI = 1.350-3.459, χ2 = 10.55, P = 0.0011). The risk of HCC was significantly higher for the CC genotype in the c.3073A>C polymorphism compared to the AA genotype in the studied populations (CC vs AA: OR = 2.575, 95%CI = 1.646-4.028, χ2 = 17.64, P < 0.0001). The C allele of the c.335T>C and c.3073A>C variants may contribute to the risk of HCC (C vs T of c.335T>C: OR = 1.512, 95%CI = 1.208-1.893, χ2 = 13.07, P = 0.0003, and C vs A of c.3073A>C: OR = 1.646, 95%CI = 1.322-2.049, χ2 = 20.03, P < 0.0001). The c.335T>C and c.3073A>C polymorphisms of the MDR1 gene were associated with the risk of occurrence of HCC in the Chinese Han population. Further investigations are needed to confirm these results in larger different populations

  4. Association of MDR1, CYP2D6, and CYP2C19 gene polymorphisms with prophylactic migraine treatment response.

    Atasayar, Gulfer; Eryilmaz, Isil Ezgi; Karli, Necdet; Egeli, Unal; Zarifoglu, Mehmet; Cecener, Gulsah; Taskapilioglu, Ozlem; Tunca, Berrin; Yildirim, Oznur; Ak, Secil; Tezcan, Gulcin; Can, Fatma Ezgi

    2016-07-15

    Prophylactic therapy response varies in migraine patients. The present study investigated the relationship between the resistance to the drugs commonly used in prophylactic therapy and the possible polymorphic variants of proteins involved in the metabolism of these drugs. Migraine patients with the MDR1 3435TT genotype exhibited a better treatment response to topiramate than migraine patients with the CC and CT genotypes (p=0.020). The MDR1 C3435T polymorphism was also found to be a higher risk factor for topiramate treatment failure in a comparison of the number of days with migraine (β2=1.152, p=0.015). However, there was no significant relationship between the treatment response to topiramate and either the CYP2D6 or CYP2C19 polymorphism, and there were no significant correlations between the treatment responses to amitriptyline, propranolol, and valproic acid and the MDR1, CYP2D6 and CYP2C19 gene polymorphisms. This is the first study to investigate the effect of the polymorphic variants on prophylactic therapy response in migraine patients. PMID:27288795

  5. MDR1 Gene C3435T and C1236T Polymorphisms among Patients with Pharmacoresistant Epilepsy and Healthy Individuals

    Nodira M. Tuychibaeva

    2014-12-01

    Full Text Available MDR1 gene C3435T and C1236T single-nucleotide polymorphisms (SNPs have been studied in 59 Uzbek patients with epilepsy aged from 1 to 40 years. The patients were resistant to anticonvulsant drugs in therapeutic doses with no remission attained. The disease duration was about two years. The DNA samples were isolated from peripheral blood of patients and healthy individuals. The study found a statistically significant difference in the frequency of the ТТ genotype of the MDR1 gene С3435Т polymorphism, which was associated both with rapid and slow drug metabolism. In the TT genotype group, the share of the patients resistant to the therapy was almost 4.8 times higher than in the control group. Despite high OR=1.9, there were statistically insignificant differences in the frequency of С1236Т SNP. The 3435C – 1236T haplotype of MDR1 gene was associated with an increase the risk of drug-resistance development in epileptic patients.

  6. Association between MDR1 gene polymorphisms and Parkinson's disease in Asian and Caucasian populations: a meta-analysis.

    Ahmed, Shiek S S J; Husain, R S Akram; Kumar, Suresh; Ramakrishnan, V

    2016-09-15

    Parkinson's disease (PD) is a complex neurodegenerative disease, its etiology is largely unknown. Studies demonstrate the association of genetic and environment factors in causing neuronal degeneration. Reports suggest that the multi-drug resistance gene (MDR1) plays a vital role in preventing the toxic substance in entering the brain, which is associated with PD. However, the association between the MDR1 polymorphisms (C1236T and C3435T) and its susceptibility to PD is inconclusive. Meta analysis was carried by retrieving literatures from databases to search the case-control studies on the associations between the MRD1 polymorphisms and PD. The pooled odds ratios (ORs) and its 95% confidence intervals (CIs) were calculated using fixed and random model to determine the association between the polymorphisms and PD susceptibility. Significant association was noticed for C1236T polymorphism and PD risk in the recessive model OR=0.80, 95% CI=0.66-0.97. Further, ethnicity based analysis showed significant association for C1236T in allelic model of Asian population and also in the recessive models of both Asian and Caucasian populations. However, insignificant associations were noticed for C3435T in all the four models. Overall, the analysis suggested that MDR1 C1236T polymorphism substantially contribute to Parkinson's disease in the recessive genetic model. PMID:27538645

  7. Functional Characterization of Sodium-dependent Multivitamin Transporter (SMVT) in MDCK-MDR1 cells and its Utilization as a Target for Drug Delivery

    Luo, Shuanghui; Kansara, Viral S.; Zhu, Xiaodong; Pal, Dhananjay; Mitra, Ashim. K.

    2008-01-01

    The objective of this research is to characterize a sodium-dependent multivitamin transporter (SMVT) in MDCK-MDR1 cells (Madin-Darby canine kidney cells transfected with the human MDR1 gene) and to investigate the feasibility of utilizing MDCK-MDR1 cell line as an in vitro model to study the permeability of biotin-conjugated prodrugs of anti-HIV protease inhibitors. Mechanism of [3H] biotin uptake and transport was delineated. Transepithelial permeability of the biotin conjugated prodrug i.e. biotin-saquinavir was also studied. Reverse transcription-polymerase chain reaction (RT-PCR) was carried out to confirm the existence of SMVT in MDCK-MDR1 cells. Biotin uptake was Na+, pH, and temperature dependent, but energyindependent. Transepithelial transport studies of biotin-saquinavir in MDCK-MDR1, wild type MDCK, and Caco-2 cells revealed that permeability of biotin-saquinavir was similar in all three cell lines. A band of SMVT mRNA at 862 bp was identified by RT-PCR. A sodium-dependent multivitamin transporter, SMVT, responsible for biotin uptake and transport, was identified and functionally characterized in MDCK-MDR1 cells. Therefore, MDCK-MDR1 cell line may be utilized as an in vitro model to study the permeability of biotin conjugated prodrugs such as HIV protease inhibitors. PMID:16749865

  8. Oral and inhaled corticosteroids: Differences in P-glycoprotein (ABCB1) mediated efflux

    Crowe, Andrew, E-mail: a.p.crowe@curtin.edu.au; Tan, Ai May

    2012-05-01

    There is concern that P-glycoprotein mediated efflux contributes to steroid resistance. Therefore, this study examined bidirectional corticosteroid transport and induction capabilities for P-glycoprotein (P-gp) to understand which of the systemic and inhaled corticosteroids interacted with P-gp to the greatest extent. Hydrocortisone, prednisolone, prednisone, methylprednisolone, and dexamethasone represented systemically active drugs, while fluticasone propionate, beclomethasone dipropionate, ciclesonide and budesonide represented inhaled corticosteroids. Aldosterone and fludrocortisone represented mineralocorticoids. All drugs were detected using individually optimised HPLC protocols. Transport studies were conducted through Caco-2 monolayers. Hydrocortisone and aldosterone had efflux ratios below 1.5, while prednisone showed a P-gp mediated efflux ratio of only 1.8 compared to its active drug, prednisolone, with an efflux ratio of 4.5. Dexamethasone and beclomethasone had efflux ratios of 2.1 and 3.3 respectively, while this increased to 5.1 for methylprednisolone. Fluticasone showed an efflux ratio of 2.3. Protein expression studies suggested that all of the inhaled corticosteroids were able to induce P-gp expression, from 1.6 to 2 times control levels. Most of the systemic corticosteroids had higher passive permeability (> 20 × 10{sup −6} cm/s) compared to the inhaled corticosteroids (> 5 × 10{sup −6} cm/s), except for budesonide, with permeability similar to the systemic corticosteroids. Inhaled corticosteroids are not transported by P-gp to the same extent as systemic corticosteroids. However, they are able to induce P-gp production. Thus, inhaled corticosteroids may have greater interactions with other P-gp substrates, but P-gp itself is less likely to influence resistance to the drugs. -- Highlights: ► Inhaled corticosteroids are only weak substrates for P-gp, including budesonide. ► Inhaled corticosteroid potent P-gp inducers especially

  9. Oral and inhaled corticosteroids: Differences in P-glycoprotein (ABCB1) mediated efflux

    There is concern that P-glycoprotein mediated efflux contributes to steroid resistance. Therefore, this study examined bidirectional corticosteroid transport and induction capabilities for P-glycoprotein (P-gp) to understand which of the systemic and inhaled corticosteroids interacted with P-gp to the greatest extent. Hydrocortisone, prednisolone, prednisone, methylprednisolone, and dexamethasone represented systemically active drugs, while fluticasone propionate, beclomethasone dipropionate, ciclesonide and budesonide represented inhaled corticosteroids. Aldosterone and fludrocortisone represented mineralocorticoids. All drugs were detected using individually optimised HPLC protocols. Transport studies were conducted through Caco-2 monolayers. Hydrocortisone and aldosterone had efflux ratios below 1.5, while prednisone showed a P-gp mediated efflux ratio of only 1.8 compared to its active drug, prednisolone, with an efflux ratio of 4.5. Dexamethasone and beclomethasone had efflux ratios of 2.1 and 3.3 respectively, while this increased to 5.1 for methylprednisolone. Fluticasone showed an efflux ratio of 2.3. Protein expression studies suggested that all of the inhaled corticosteroids were able to induce P-gp expression, from 1.6 to 2 times control levels. Most of the systemic corticosteroids had higher passive permeability (> 20 × 10−6 cm/s) compared to the inhaled corticosteroids (> 5 × 10−6 cm/s), except for budesonide, with permeability similar to the systemic corticosteroids. Inhaled corticosteroids are not transported by P-gp to the same extent as systemic corticosteroids. However, they are able to induce P-gp production. Thus, inhaled corticosteroids may have greater interactions with other P-gp substrates, but P-gp itself is less likely to influence resistance to the drugs. -- Highlights: ► Inhaled corticosteroids are only weak substrates for P-gp, including budesonide. ► Inhaled corticosteroid potent P-gp inducers especially fluticasone and

  10. Functional impact of ABCB1 variants on interactions between P-glycoprotein and methadone.

    Chin-Chuan Hung

    Full Text Available Methadone is a widely used substitution therapy for opioid addiction. Large inter-individual variability has been observed in methadone maintenance dosages and P-glycoprotein (P-gp was considered to be one of the major contributors. To investigate the mechanism of P-gp's interaction with methadone, as well as the effect of genetic variants on the interaction, Flp-In™-293 cells stably transfected with various genotypes of human P-gp were established in the present study. The RNA and protein expression levels of human P-gp were confirmed by real-time quantitative RT-PCR and western blot, respectively. Utilizing rhodamine 123 efflux assay and calcein-AM uptake study, methadone was demonstrated to be an inhibitor of wild-type human P-gp via non-competitive kinetic (IC50 = 2.17±0.10 µM, while the variant-type human P-gp, P-gp with 1236T-2677T-3435T genotype and P-gp with 1236T-2677A-3435T genotype, showed less inhibition potency (IC50 = 2.97±0.09 µM and 4.43±1.10 µM, respectively via uncompetitive kinetics. Methadone also stimulated P-gp ATPase and inhibited verapamil-stimulated P-gp ATPase activity under therapeutic concentrations. These results may provide a possible explanation for higher methadone dosage requirements in patients carrying variant-type of P-gp and revealed the possible drug-drug interactions in patients who receive concomitant drugs which are also P-gp substrates.

  11. Functional Characterization of Sodium-dependent Multivitamin Transporter (SMVT) in MDCK-MDR1 cells and its Utilization as a Target for Drug Delivery

    Luo, Shuanghui; Kansara, Viral S.; Zhu, Xiaodong; Pal, Dhananjay; Mitra, Ashim K.

    2006-01-01

    The objective of this research is to characterize a sodium-dependent multivitamin transporter (SMVT) in MDCK-MDR1 cells (Madin-Darby canine kidney cells transfected with the human MDR1 gene) and to investigate the feasibility of utilizing MDCK-MDR1 cell line as an in vitro model to study the permeability of biotin-conjugated prodrugs of anti-HIV protease inhibitors. Mechanism of [3H] biotin uptake and transport was delineated. Transepithelial permeability of the biotin conjugated prodrug i.e....

  12. MDR1 C3435T基因多态性对环孢素体内代谢影响的荟萃分析%Meta-analysis of the effect of MDR1 C3435T polymorphism on cyclosporine pharmacokinetics

    姜志平; 王一任; 徐萍; 刘荣荣; 赵谢兰; 陈方平

    2008-01-01

    目的 通过荟萃分析进一步观察MDR1 C3435T 基因多态性对于环孢素体内代谢的影响.方法 通过Pubmed搜索C3435T 基因多态性对于环孢素体内代谢影响的相关文献,提取AUC0-4, AUC0-12, AUC0-inf,Cmax, CL/F, 和C0等药物动力学参数,使用STATA 9.1软件进行荟萃分析.结果 共有14篇,包括1 036名受试者符合本次荟萃分析的入选条件,荟萃分析显示在C3435T野生型杂合子(CC)中,AUC0-12低于其他基因型的受试者.在白种人中,C3435T野生型杂合子(CC)携带者的C0低于其他基因型的白种受试者.其他药物动力学参数在C3435T各基因型之间未见显著差异.结论 本荟萃分析没有发现MDR1 C3435T 基因多态性对于环孢素体内代谢有较大的影响,但是观察指标的选择是观察结果差异的原因之一;MDR1 C3435T表型和基因型的相关性可能存在种族差异.

  13. The Effect of ABCB1 C3435T Polymorphism on Cyclosporine Dose Requirements in Kidney Transplant Recipients: A Meta-Analysis.

    Lee, Jun; Wang, Rongrong; Yang, Yuan; Lu, Xiaoyang; Zhang, Xingguo; Wang, Linrun; Lou, Yan

    2015-08-01

    Cyclosporine A (CsA) is a substrate of the multi-drug efflux pump P-glycoprotein (P-gp) encoded by ABCB1. Among the various single nucleotide polymorphisms (SNPs) of ABCB1, C3435T has been extensively investigated to determine the relationship with the pharmacokinetics of CsA. However, the results are controversial. This meta-analysis was designed to evaluate the influence of C3435T SNP on the dose-adjusted trough (C0 /D) and peak (Cmax /D) concentrations of CsA. Based on a literature search of four authoritative databases, 13 studies since 2001 concerning 1293 kidney transplant recipients were included. The results indicated a significant difference of C0 /D and Cmax /D between 3435CC and 3435TT genotype carriers (weighted mean difference (WMD) of C0 /D: 4.18 (ng ml(-1))/(mg kg(-1)), 95% CIs: 1.00-7.37, p = 0.01; WMD of Cmax /D: 20.85 (ng ml(-1))/(mg kg(-1)), 95% CIs: 2.25-39.46, p = 0.03). Subgroup analysis by ethnicity demonstrated that C0 /D was lower in Asian CC versus TT genotype carriers (WMD = 10.32 (ng ml(-1))/(mg kg(-1)), 95% CIs: 4.78-15.85, p = 0.0003) but did not vary by genotype for Caucasian recipients. Moreover, significant variation of C0 /D was found at 1 week and 1-3 months after transplantation between CC and TT genotype carriers. Therefore, this meta-analysis showed a correlation between ABCB1 C3435T polymorphism and the dose-adjusted concentration of CsA. Patients with 3435CC genotype will require a higher dose of CsA to achieve target therapeutic concentrations when compared with 3435TT carriers after kidney transplantation, especially in the Asian population and especially during the early and middle time periods after transplantation. PMID:25536375

  14. PfCRT and PfMDR1 modulate interactions of artemisinin derivatives and ion channel blockers

    Eastman, Richard T.; Khine, Pwint; Huang, Ruili; Thomas, Craig J.; Su, Xin-zhuan

    2016-01-01

    Treatment of the symptomatic asexual stage of Plasmodium falciparum relies almost exclusively on artemisinin (ART) combination therapies (ACTs) in endemic regions. ACTs combine ART or its derivative with a long-acting partner drug to maximize efficacy during the typical three-day regimen. Both laboratory and clinical studies have previously demonstrated that the common drug resistance determinants P. falciparum chloroquine resistance transporter (PfCRT) and multidrug resistance transporter (PfMDR1) can modulate the susceptibility to many current antimalarial drugs and chemical compounds. Here we investigated the parasite responses to dihydroartemisinin (DHA) and various Ca2+ and Na+ channel blockers and showed positively correlated responses between DHA and several channel blockers, suggesting potential shared transport pathways or mode of action. Additionally, we demonstrated that PfCRT and PfMDR1 could also significantly modulate the pharmacodynamic interactions of the compounds and that the interactions were influenced by the parasite genetic backgrounds. These results provide important information for better understanding of drug resistance and for assessing the overall impact of drug resistance markers on parasite response to ACTs. PMID:27147113

  15. PfCRT and PfMDR1 modulate interactions of artemisinin derivatives and ion channel blockers.

    Eastman, Richard T; Khine, Pwint; Huang, Ruili; Thomas, Craig J; Su, Xin-Zhuan

    2016-01-01

    Treatment of the symptomatic asexual stage of Plasmodium falciparum relies almost exclusively on artemisinin (ART) combination therapies (ACTs) in endemic regions. ACTs combine ART or its derivative with a long-acting partner drug to maximize efficacy during the typical three-day regimen. Both laboratory and clinical studies have previously demonstrated that the common drug resistance determinants P. falciparum chloroquine resistance transporter (PfCRT) and multidrug resistance transporter (PfMDR1) can modulate the susceptibility to many current antimalarial drugs and chemical compounds. Here we investigated the parasite responses to dihydroartemisinin (DHA) and various Ca(2+) and Na(+) channel blockers and showed positively correlated responses between DHA and several channel blockers, suggesting potential shared transport pathways or mode of action. Additionally, we demonstrated that PfCRT and PfMDR1 could also significantly modulate the pharmacodynamic interactions of the compounds and that the interactions were influenced by the parasite genetic backgrounds. These results provide important information for better understanding of drug resistance and for assessing the overall impact of drug resistance markers on parasite response to ACTs. PMID:27147113

  16. Tissue-specific alterations in expression and function of P-glycoprotein in streptozotocininduced diabetic rats

    Lu-lu ZHANG; Guang-ji WANG; Lin XIE; Liang LU; Shi JIN; Xin-yue JING; Dan YAO; Nan HU; Li LIU; Ru DUAN; Xiao-dong LIU

    2011-01-01

    Aim: To investigate the changes of expression and function of P-glycoprotein (P-GP) in cerebral cortex, hippocampus, liver, intestinal mucosa and kidney of streptozocin-induced diabetic rats.Methods: Diabetic rats were prepared via a single dose of streptozocin (65 mg/kg, ip). Abcb1/P-GP mRNA and protein expression levels in tissues were evaluated using quantitative real time polymerase chain reaction (QRT-PCR) analysis and Western blot, respectively.P-GP function was investigated via measuring tissue-to-plasma concentration ratios and body fluid excretion percentages of rhodamine 123.Results: In 5- and 8-week diabetic rats, Abcb1a mRNA levels were significantly decreased in cerebral cortices and intestinal mucosa,but dramatically increased in hippocampus and kidney. In liver, the level was increased in 5-week diabetic rats, and decreased in 8-week diabetic rats. Abcb1b mRNA levels were increased in cerebral cortex, hippocampus and kidney, but reduced in liver and intestinal mucosa in the diabetic rats. Western blot results were in accordance with the alterations of Abcb1a mRNA levels in most tissues examined. P-GP activity was markedly decreased in most tissues of diabetic rats, except kidney tissues.Conclusion: Alterations in the expression and function of Abcb1/P-GP under diabetic conditions are tissue specific, Abcb1 specific and diabetic duration-dependent.

  17. A common polymorphism in the ABCB1 gene is associated with side effects of PGP-dependent antidepressants in a large naturalistic Dutch cohort.

    Bet, P M; Verbeek, E C; Milaneschi, Y; Straver, D B M; Uithuisje, T; Bevova, M R; Hugtenburg, J G; Heutink, P; Penninx, B W J H; Hoogendijk, W J G

    2016-04-01

    The drug efflux transporter permeability glycoprotein (PGP) and cytochrome P450 (CYP) 2C19 are important for eliminating antidepressants from the brain and body. The ABCB1 gene, encoding for PGP, and CYP2C19 gene have several variants that could influence enzyme function and thereby the effect of PGP- and 2C19-dependent antidepressants. We investigated the association of antidepressant side effect and common genetic variation in 789 antidepressant users. In PGP-dependent antidepressant users, the A-allele of the rs2032588 single-nucleotide polymorphism (SNP) was associated with a lower number of side effects after adjusting for gender, age, dosage and duration of use, (B=-0.44, q=4.6 × 10(-3)). This association was different from and absent in non-PGP-dependent antidepressant users. Other SNP associations as well as an interaction analysis between the rs2032588 SNP and the CYP2C19 SNPs were not statistically significant after adjusting for covariates and multiple comparisons. The association of rs2032588 with antidepressant side effects suggests the involvement of the ABCB1 genotype in the clinical pharmacology of PGP-dependent antidepressants. PMID:25987242

  18. Quantitative and Mechanistic Assessment of Model Lipophilic Drugs in Micellar Solutions in the Transport Kinetics Across MDR1-MDCK Cell Monolayers.

    Ho, Norman F H; Nielsen, James; Peterson, Michelle; Burton, Philip S

    2016-02-01

    An approach to characterizing P-glycoprotein (Pgp) interaction potential for sparingly water-soluble compounds was developed using bidirectional transport kinetics in MDR1-MDCK cell monolayers. Paclitaxel, solubilized in a dilute polysorbate 80 (PS80) micellar solution, was used as a practical example. Although the passage of paclitaxel across the cell monolayer was initially governed by the thermodynamic activity of the micelle-solubilized drug solution, Pgp inhibition was sustained by the thermodynamic activity (i.e., critical micelle concentration) of the PS80 micellar solution bathing the apical (ap) membrane. The mechanistic understanding of the experimental strategies and treatment of data was supported by a biophysical model expressed in the form of transport events occurring at the ap and basolateral (bl) membranes in series whereas the vectorial directions of the transcellular kinetics were accommodated. The derived equations permitted the stepwise quantitative delineation of the Pgp efflux activity (inhibited and uninhibited by PS80) and the passive permeability coefficient of the ap membrane, the passive permeability at the bl membrane and, finally, the distinct coupling of these with efflux pump activity to identify the rate-determining steps and mechanisms. The Jmax/KM(∗) for paclitaxel was in the order of 10(-4) cm/s and the ap- and bl-membrane passive permeability coefficients were asymmetric, with bl-membrane permeability significantly greater than ap. PMID:26869435

  19. Astrocytes drive upregulation of the multidrug resistance transporter ABCB1 (P-Glycoprotein) in endothelial cells of the blood-brain barrier in mutant superoxide dismutase 1-linked amyotrophic lateral sclerosis.

    Qosa, Hisham; Lichter, Jessica; Sarlo, Mark; Markandaiah, Shashirekha S; McAvoy, Kevin; Richard, Jean-Philippe; Jablonski, Michael R; Maragakis, Nicholas J; Pasinelli, Piera; Trotti, Davide

    2016-08-01

    The efficacy of drugs targeting the CNS is influenced by their limited brain access, which can lead to complete pharmacoresistance. Recently a tissue-specific and selective upregulation of the multidrug efflux transporter ABCB1 or P-glycoprotein (P-gp) in the spinal cord of both patients and the mutant SOD1-G93A mouse model of amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disease that prevalently kills motor neurons has been reported. Here, we extended the analysis of P-gp expression in the SOD1-G93A ALS mouse model and found that P-gp upregulation was restricted to endothelial cells of the capillaries, while P-gp expression was not detected in other cells of the spinal cord parenchyma such as astrocytes, oligodendrocytes, and neurons. Using both in vitro human and mouse models of the blood-brain barrier (BBB), we found that mutant SOD1 astrocytes were driving P-gp upregulation in endothelial cells. In addition, a significant increase in reactive oxygen species production, Nrf2 and NFκB activation in endothelial cells exposed to mutant SOD1 astrocytes in both human and murine BBB models were observed. Most interestingly, astrocytes expressing FUS-H517Q, a different familial ALS-linked mutated gene, also drove NFκB-dependent upregulation of P-gp. However, the pathway was not dependent on oxidative stress but rather involved TNF-α release. Overall, these findings indicated that nuclear translocation of NFκB was a converging mechanism used by endothelial cells of the BBB to upregulate P-gp expression in mutant SOD1-linked ALS and possibly other forms of familial ALS. GLIA 2016 GLIA 2016;64:1298-1313. PMID:27158936

  20. EXPRESSION AND CLINICAL SIGNIFICANCE OF MULTIDRUG RESISTANCE GENE AND MULTIDRUG RESISTANCE-ASSOCIATED PROTEIN GENE IN ACUTE LEUKEMIA

    LAI Yong-rong; MA Jie; LU Yu-ying; NU Wei-lin; XIANG Zhi-fu

    1999-01-01

    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.

  1. Neurological toxicity after phenytoin infusion in a pediatric patient with epilepsy: influence of CYP2C9, CYP2C19 and ABCB1 genetic polymorphisms.

    Dorado, P; López-Torres, E; Peñas-Lledó, E M; Martínez-Antón, J; Llerena, A

    2013-08-01

    Pharmacogenetic studies have shown that genetic defects in drug-metabolizing enzymes encoded by CYP2C9, CYP2C19 genes and by the transporter ABCB1 gene can influence phenytoin (PTH) plasma levels and toxicity. The patient reported here is a 2-year-old girl with a medical history of cryptogenic (probably symptomatic) epilepsy, who had her first focal seizure with secondary generalization at 13 months of age. She initially received oral valproate treatment and three months later, she was prescribed an oral oxcarbazepine treatment. At 20 months of age, she was admitted to the Emergency Department because of generalized convulsive Status Epilepticus needing to be immediately treated with rectal diazepam (0.5 mg kg(-1)), intravenous diazepam (0.3 mg kg(-1)), and intravenous phenytoin with an initial-loading dose of 15 mg kg(-1). However, two hours after the initial-loading dose of PTH, the patient developed dizziness, nystagmus, ataxia and excessive sedation. Other potential causes of PTH toxicity were excluded such as drug interactions, decreased albumin or lab error. Therefore, to explain the neurological toxicity, PTH plasma levels and CYP2C9, CYP2C19 and ABCB1 genetic polymorphisms were analyzed. Initial plasma PTH levels were higher than expected (69 mg l(-1); normal range: 10-20 mg l(-1)), and the patient was homozygous for the CYP2C9*2 allele, heterozygous for the CYP2C19*4 allele and homozygous for the 3435C and 1236C ABCB1 alleles. Present findings support the previously established relationship between CYP2C9 and CYP2C19 genetic polymorphisms and the increased risk to develop PTH toxicity owing to high plasma concentrations. Nevertheless, although the association of these genes with PTH-induced adverse effects has been well-documented in adult populations, this is the first report examining the influence of these genetic polymorphisms on PTH plasma levels and toxicity in a pediatric patient. PMID:22641027

  2. The antinociceptive effect and adverse drug reactions of oxycodone in human experimental pain in relation to genetic variations in the OPRM1 and ABCB1 genes

    Zwisler, Stine T; Enggaard, Thomas P; Noehr-Jensen, Lene;

    2010-01-01

    the wild-type genotype in the cold pressor test (25% reduction vs. 15%, P = 0.015 in the discomfort rating and 25% reduction vs. 12%, P = 0.007 in the pain time AUC) and less adverse drug reactions. The combined wild-type genotype 3435CC-2677GG was associated with less antinociceptive effect of......The aim of this study was to search for a possible association between the variant allele of the single nucleotide polymorphisms A118G in the OPRM1 gene and C3435T and G2677T/A in the ABCB1 gene and altered antinociceptive effect and adverse drug reactions of oxycodone. Thirty-three healthy...... subjects exposed to experimental pain including electrical stimulation and the cold pressor test were included. A118G: We found that the variant G allele was associated with reduced antinociceptive effect as measured by pain tolerance thresholds to single electrical nerve stimulation (8% increase vs. 25...

  3. Acute kidney injury in a preterm infant homozygous for the C3435T polymorphism in the ABCB1 gene given oral morphine

    Pogliani, Laura; Mameli, Chiara; Cattaneo, Dario; Clementi, Emilio; Meneghin, Fabio; Radice, Sonia; Bruno, Simona; Zuccotti, Gian Vincenzo

    2012-01-01

    A 34-week infant born from a mother with a history of drug abuse developed neonatal abstinence syndrome (NAS) in the first hours of life. Urine drug screening was positive for cocaine and heroin. The infant developed acute kidney injury and bilateral hydronephrosis while receiving oral morphine for control of NAS. Cessation of morphine therapy and urinary catheterization resulted in a rapid and complete resolution of the symptoms. Our patient was homozygous for the C3435T polymorphism in the ABCB1 gene, a polymorphism previously associated with impaired P-glycoprotein activity. We hypothesize that acute renal toxicity was related to accumulation of morphine within urothelial cells due to genetically determined impaired P-glycoprotein activity. PMID:26019822

  4. Characterization of Human Colorectal Cancer MDR1/P-gp Fab Antibody

    Xuemei Zhang; Gary Guishan Xiao; Ying Gao

    2013-01-01

    In this study, the peptide sized 21 kDa covering P-gp transmembrane region was first prepared for generating a novel mouse monoclonal antibody Fab fragment with biological activity against multiple drug resistance protein P-gp21 by phage display technology. Phage-displayed antibody library prepared from mice spleen tissues was selected against the recombinant protein P-gp21 with five rounds of panning. A number of clones expressing Fab bound to P-gp21, showing neutralized activity in vitro, w...

  5. Selected ABCB1, ABCB4 and ABCC2 Polymorphisms Do Not Enhance the Risk of Drug-Induced Hepatotoxicity in a Spanish Cohort

    Ulzurrun, Eugenia; Stephens, Camilla; Ruiz-Cabello, Francisco; Robles-Diaz, Mercedes; Saenz-López, Pablo; Hallal, Hacibe; Soriano, German; Roman, Eva; Fernandez, M. Carmen; Lucena, M. Isabel; Andrade, Raúl J.

    2014-01-01

    Background and Aims Flawed ABC transporter functions may contribute to increased risk of drug-induced liver injury (DILI). We aimed to analyse the influence of genetic variations in ABC transporters on the risk of DILI development and clinical presentations in a large Spanish DILI cohort. Methods A total of ten polymorphisms in ABCB1 (1236T>C, 2677G>T,A, 3435T>C), ABCB4 (1954A>G) and ABCC2 (−1774G>del, −1549A>G, −24C>T, 1249G>A, 3972C>T and 4544G>A) were genotyped using Taqman 5′ allelic discrimination assays or sequencing in 141 Spanish DILI patients and 161 controls. The influence of specific genotypes, alleles and haplotypes on the risk of DILI development and clinical presentations was analysed. Results None of the individual polymorphisms or haplotypes was found to be associated with DILI development. Carriers homozygous for the ABCC2 −1774del allele were however only found in DILI patients. Hence, this genotype could potentially be associated with increased risk, though its low frequency in our Spanish cohort prevented a final conclusion. Furthermore, carriers homozygous for the ABCC2 −1774G/−1549A/−24T/1249G/3972T/4544G haplotype were found to have a higher propensity for total bilirubin elevations when developing DILI. Conclusions Our findings do not support a role for the analysed polymorphisms in the ABCB1, ABCB4 and ABCC2 transporter genes in DILI development in Spanish patients. The ABCC2 −1774deldel genotype was however restricted to DILI cases and could potentially contribute to enhanced DILI susceptibility. PMID:24732756

  6. The ABCB1, rs9282564, AG and TT Genotypes and the COMT, rs4680, AA Genotype are less frequent in Deceased Patients with Opioid Addiction (DOA) than in Living Patients with Opioid Addiction (LOA)

    Christoffersen, Dorte J; Damkier, Per; Feddersen, Søren;

    2016-01-01

    Sudden death due to acute intoxication occurs frequently in patients with opioid addiction (OA). In order to examine if certain genotypes were associated with this, we examined the frequencies of 29 SNPs located in candidate genes related to opioid pharmacology: ABCB1, OPRM1, UGT2B7, CYP3A5, CYP2...

  7. The association of C3435T single-nucleotide polymorphism, Pgp-glycoprotein gene expression levels and carbamazepine maintenance dose in patients with epilepsy

    Sterjev Z

    2012-04-01

    Full Text Available Zoran Sterjev1, Gordana Kiteva Trencevska2, Emilija Cvetkovska2, Igor Petrov2, Igor Kuzmanovski2, Jasmina T Ribarska3, Aleksandra K Nestorovska1, Nadica Matevska1, Zorica Naumovska1, Suzana Jolevska-Trajkovic3, Aleksandar Dimovski1, Ljubica Suturkova11Institute of Pharmaceutical Chemistry, Faculty of Pharmacy Skopje, Republic of Macedonia; 2Clinic of Neurology, Faculty of Medicine, Skopje, Republic of Macedonia; 3Institute of Pharmaceutical Analysis, Faculty of Pharmacy Skopje, Republic of MacedoniaAbstract: The ABCB1 gene encodes the P-glycoprotein (Pgp protein, which is thought to transport various antiepileptic drugs. The single nucleotide polymorphism (SNP (C3435T in exon 26 of this gene correlates with the altered expression levels of P-glycoprotein, range of drug response and clinical conditions. In order to investigate the influence of this polymorphism on the susceptibility to and efficacy of carbamazepine therapy, we evaluated the allelic frequency and genotype distribution of this variant in 162 epilepsy patients from the Republic of Macedonia. Statistically significant differences were detected neither in the allelic frequency and genotype distribution between carbamazepine-resistant and carbamazepine-responsive epilepsy patients nor between the subgroups of carbamazepine (CBZ-responsive patients treated with different CBZ doses. However, the T-allele was enriched in CBZ-responsive patients who required higher maintenance CBZ doses, This observation was substantiated by the findings that the median total plasma levels were the lowest in patients with CC (20 µmol/L followed by CT (23 µmol/L and TT (29 µmol/L genotypes. Patients with a CC genotype also had a higher likelihood of response compared to patients with CT or TT genotypes over a wide range (400–1000 mg/day of initial doses of CBZ. The T allele showed a reduced expression of ~5% compared to the C allele in peripheral blood mononuclear cells in heterozygotes for the variant

  8. The role of 99mTc-MIBI scintigraphy in the assessment of MDR1 overexpression in patients with musculoskeletal sarcomas: comparison with therapy response

    The occurrence of multidrug resistance (MDR), which is in part due to the overexpression of P-glycoprotein (Pgp), is a major problem in neoadjuvant therapy of malignant musculoskeletal tumours. The aim of this study was to investigate the role of technetium-99m hexakis-2-methoxyisobutylisonitrile (99mTc-MIBI) scintigraphy for functional imaging of the MDR1 phenotype in patients with musculoskeletal sarcomas. We aimed to compare 99mTc-MIBI uptake and washout kinetics with the expression of Pgp and with chemotherapy response. Twenty-five patients (16 males and 9 females, aged between 8 and 65 years) with malignant musculoskeletal tumours were studied. After injection of 555-740 MBq 99mTc-MIBI, dynamic flow images of the involved area were obtained for 3 min, and planar images were acquired at 10 min and 1 h. From the dynamic images, a tumour perfusion index (TPI) was obtained using Patlak-Rutland analysis. Tumour to background (T/B) ratios of both early and delayed images and percent wash-out rate (WR%) of 99mTc-MIBI were calculated. Immunohistochemical analysis of Pgp was performed on biopsy specimens and the degree of expression was graded according to a semiquantitative scoring system, from 0 to 6. After neoadjuvant therapy, tumour response was assessed by examining the ratio of viable cells and by detecting percent necrosis. Scintigraphic results were compared with Pgp status and therapy response. Irrespective of the Pgp status, all patients showed significant perfusion and 99mTc-MIBI uptake in early images. There was not a significant correlation between T/B ratios of early and delayed images and Pgp expression. We observed a positive correlation between WR% and Pgp status (r=0.61, P99mTc-MIBI was significantly higher in patients with high Pgp expression than in those with a low Pgp score (33%±9% vs 17%±9%). Therapy response was determined in 21 of 25 patients, and in only 5 of 21 cases was the percent necrosis more than 90%. Neither Pgp expression rate nor WR

  9. The role of {sup 99m}Tc-MIBI scintigraphy in the assessment of MDR1 overexpression in patients with musculoskeletal sarcomas: comparison with therapy response

    Burak, Z.; Erinc, R.; Oezcan, Z.; Dirlik, A. [Dept. of Nuclear Medicine, Ege University Medical Faculty, Bornova (Turkey); Ersoy, Oe.; Basdemir, G. [Dept. of Pathology, Ege University Medical Faculty, Izmit (Turkey); Moretti, J.-L. [Service de Medecine Nucleaire et Biophysique, Univ. Paris 8 (France); Sabah, D. [Dept. of Orthopaedics, Ege University Medical Faculty, Izmir (Turkey)

    2001-09-01

    The occurrence of multidrug resistance (MDR), which is in part due to the overexpression of P-glycoprotein (Pgp), is a major problem in neoadjuvant therapy of malignant musculoskeletal tumours. The aim of this study was to investigate the role of technetium-99m hexakis-2-methoxyisobutylisonitrile ({sup 99m}Tc-MIBI) scintigraphy for functional imaging of the MDR1 phenotype in patients with musculoskeletal sarcomas. We aimed to compare {sup 99m}Tc-MIBI uptake and washout kinetics with the expression of Pgp and with chemotherapy response. Twenty-five patients (16 males and 9 females, aged between 8 and 65 years) with malignant musculoskeletal tumours were studied. After injection of 555-740 MBq {sup 99m}Tc-MIBI, dynamic flow images of the involved area were obtained for 3 min, and planar images were acquired at 10 min and 1 h. From the dynamic images, a tumour perfusion index (TPI) was obtained using Patlak-Rutland analysis. Tumour to background (T/B) ratios of both early and delayed images and percent wash-out rate (WR%) of {sup 99m}Tc-MIBI were calculated. Immunohistochemical analysis of Pgp was performed on biopsy specimens and the degree of expression was graded according to a semiquantitative scoring system, from 0 to 6. After neoadjuvant therapy, tumour response was assessed by examining the ratio of viable cells and by detecting percent necrosis. Scintigraphic results were compared with Pgp status and therapy response. Irrespective of the Pgp status, all patients showed significant perfusion and {sup 99m}Tc-MIBI uptake in early images. There was not a significant correlation between T/B ratios of early and delayed images and Pgp expression. We observed a positive correlation between WR% and Pgp status (r=0.61, P<0.01), and the wash-out rate of {sup 99m}Tc-MIBI was significantly higher in patients with high Pgp expression than in those with a low Pgp score (33%{+-}9% vs 17%{+-}9%). Therapy response was determined in 21 of 25 patients, and in only 5 of 21 cases

  10. ABCB1基因 rs1045642位点多态性与文拉法辛疗效的关联研究%Relationship between ABCB1 rs1045642 polymorphism and therapeutic effect of venlafaxine in patients with depression

    李文平; 张志珺; 孙晓燕; 高琪; 耿磊钰; 浦梦佳; 史艳艳; 徐治

    2013-01-01

    Objective: To investigate the role of ABCB1 rs1045642 polymorphism in antidepressant response . Methods:Eighty-nine Chinese Han patients received venlafaxine 75-150 mg for at least 6 weeks,of which 88 cases were followed up for 8 weeks.The Hamilton depression scale-17(HAMD-17) was used to evaluate the severity of depressive symptoms and the therapeutic effects .The single nucleotide polymorphisms ( SNPs ) rs1045642 of ABCB1 gene was detected using gene chips , then the associations of single locus with treatment response were analyzed using Unphased 3.0.13.Results: (1) There were no significant differences of gender ,age,years of education,family history, episode times, and the baseline scores of HAMD-17 between responders and non-responders (all P>0.05).(2) There were also no significant differences of gender ,age,years of education,family history ,episode times and baseline scores of HAMD-17 between remitters and non-remitters ( all P >0.05 ) . (3) Single locus association analysis: The SNPs rs1045642 genotype and allele distribution frequency of ABCB1 gene between responders and non-responders and between remitters and non-remitters had no significant differences ( all P>0.05 ) .Conclusion:There is no ABCB1 rs1045642 polymorphism associated with antidepressant response , it require replication in more homogeneous and larger samples .%目的:探讨ABCB1基因rs1045642位点多态性对抗抑郁剂文拉法辛疗效的影响。方法:纳入统计的89例抑郁症患者服用抗抑郁剂文拉法辛75~150 mg并随访6周,其中88例随访8周。使用汉密尔顿抑郁17项量表( HAMD-17)评定抑郁症状的严重程度和治疗效果。采用基因芯片检测ABCB1基因的单核苷酸多态性( SNPs) rs1045642,并通过Unphased3.0.13软件分析rs1045642位点与文拉法辛疗效的关联性。结果:(1)6周有效组和无效组间在性别、年龄、教育程度、家族史、发病次数及HAMD-17项基线分数