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Sample records for abcb1-mediated doxorubicin-resistant plhc-1

  1. Combined Effects of Radiation and Mercury on PLHC-1 Cells

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    Kim, Jin Kyu; Cha, Min Kyoung; Ryu, Tae Ho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Han, Min [Hankook Samgong Co. Osan (Korea, Republic of); Nili, Mohammad [Dawnesh Radiation Research Institute, Barcelona (Spain)

    2011-05-15

    It is inevitable for living objects to expose themselves to multiple factors present in the environment. The combined effect of multi-factors is hard to estimate and predict in advance. Especially factors harmful to organisms can synergistically interact with each other. When the effect of the combined action is greater than expected additivity, it is called synergism or supra-additivity. Ionizing radiation can cause cell death, mainly due to its ability to produce reactive oxygen species in cells. Mercury is one of widespread environmental pollutants which is known to have toxic effects on organisms. There are many reports indicating its genotoxic potential in a variety of aquatic species. Synergistic effects of radiation and mercury on human cells was previously reported. Aerobically growing organisms suffer from exposure to oxidative stress, caused by partially reduced forms of molecular oxygen, known as reactive oxygen species. These are highly reactive and capable of damaging cellular constituents such as DNA, lipids and proteins. Consequently, cells from many different organisms have evolved mechanisms to protect their components against reactive oxygen species. Reactive oxygen species can also be formed by exposure of cells either to ionizing radiation or redox cycling chemicals present in the environment like heavy metals. PLHC-1 hepatoma cell line derived from top minnow (Poeciliopsis lucida) is the most commonly used cell line in toxicology. The PLHC-1 cells are easy to cultivate, and can be used for screening the toxicity of chemicals. The present study was done to evaluate the combined effects of radiation with mercury chloride on the PLHC-1 cells

  2. Enzastaurin inhibits ABCB1-mediated drug efflux independently of effects on protein kinase C signalling and the cellular p53 status.

    Science.gov (United States)

    Michaelis, Martin; Rothweiler, Florian; Löschmann, Nadine; Sharifi, Mohsen; Ghafourian, Taravat; Cinatl, Jindrich

    2015-07-10

    The PKCβ inhibitor enzastaurin was tested in parental neuroblastoma and rhabdomyosarcoma cell lines, their vincristine-resistant sub-lines, primary neuroblastoma cells, ABCB1-transduced, ABCG2-transduced, and p53-depleted cells. Enzastaurin IC50s ranged from 3.3 to 9.5 μM in cell lines and primary cells independently of the ABCB1, ABCG2, or p53 status. Enzastaurin 0.3125 μM interfered with ABCB1-mediated drug transport. PKCα and PKCβ may phosphorylate and activate ABCB1 under the control of p53. However, enzastaurin exerted similar effects on ABCB1 in the presence or absence of functional p53. Also, enzastaurin inhibited PKC signalling only in concentrations ≥ 1.25 μM. The investigated cell lines did not express PKCβ. PKCα depletion reduced PKC signalling but did not affect ABCB1 activity. Intracellular levels of the fluorescent ABCB1 substrate rhodamine 123 rapidly decreased after wash-out of extracellular enzastaurin, and enzastaurin induced ABCB1 ATPase activity resembling the ABCB1 substrate verapamil. Computational docking experiments detected a direct interaction of enzastaurin and ABCB1. These data suggest that enzastaurin directly interferes with ABCB1 function. Enzastaurin further inhibited ABCG2-mediated drug transport but by a different mechanism since it reduced ABCG2 ATPase activity. These findings are important for the further development of therapies combining enzastaurin with ABC transporter substrates.

  3. Graphene nanoplatelets spontaneously translocate into the cytosol and physically interact with cellular organelles in the fish cell line PLHC-1

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    Lammel, Tobias; Navas, José M., E-mail: jmnavas@inia.es

    2014-05-01

    Highlights: • We assessed the cytotoxicity and uptake of graphene nanomaterials in PLHC-1 cells. • GO and CXYG nanoplatelets caused physical injury of the plasma membrane. • GO and CXYG accumulated in the cytosol and interacted with cellular organelles. • PLHC-1 cells exposed to GO/CXYG demonstrated high ROS levels but low cytotoxicity. • ROS formation was related with GO/CXYG-induced structural damage of mitochondria. - Abstract: Graphene and graphene derivatives constitute a novel class of carbon-based nanomaterials being increasingly produced and used in technical and consumer applications. Release of graphene nanoplatelets during the life cycle of these applications may result in human and environmental exposure calling for assessment of their potential to cause harm to humans and wildlife. This study aimed to assess the toxicity of graphene oxide (GO) and carboxyl graphene (CXYG) nanoplatelets to non-mammalian species using the fish cell line PLHC-1 as in vitro model. The cytotoxicity of GO and CXYG was assessed using different assays measuring alterations in plasma membrane integrity, metabolic activity, and lysosomal and mitochondrial function. The induction of oxidative stress was assessed by measuring intracellular reactive oxygen species (ROS) levels. Interaction with the plasma membrane and internalization of nanoplatelets were investigated by electron microscopy. Graphene nanoplatelets spontaneously penetrated through the plasma membrane and accumulated in the cytosol, where they further interacted with mitochondrial and nuclear membranes. PLHC-1 cells demonstrated significantly reduced mitochondrial membrane potential (MMP) and increased ROS levels at 16 μg/ml GO and CXYG (72 h), but barely any decrease in cell viability. The observation of intracellular graphene accumulations not enclosed by membranes suggests that GO and CXYG internalization in fish hepatoma cells occurs through an endocytosis-independent mechanism.

  4. Toxicological assessment of indium nitrate on aquatic organisms and investigation of the effects on the PLHC-1 fish cell line

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    Zurita, Jorge L. [National Institute of Toxicology and Forensic Sciences, Av. Dr Fedriani s/n, 41009, Seville (Spain); Jos, Angeles [Area of Toxicology, University of Seville, Prof. Garcia Gonzalez 2, 41012, Seville (Spain); Peso, Ana del; Salguero, Manuel [National Institute of Toxicology and Forensic Sciences, Av. Dr Fedriani s/n, 41009, Seville (Spain); Camean, Ana M. [Area of Toxicology, University of Seville, Prof. Garcia Gonzalez 2, 41012, Seville (Spain); Lopez-Artiguez, Miguel [National Institute of Toxicology and Forensic Sciences, Av. Dr Fedriani s/n, 41009, Seville (Spain); Repetto, Guillermo [National Institute of Toxicology and Forensic Sciences, Av. Dr Fedriani s/n, 41009, Seville (Spain); Area of Toxicology, University of Seville, Prof. Garcia Gonzalez 2, 41012, Seville (Spain)], E-mail: repetto@us.es

    2007-11-15

    Indium nitrate is mainly used as a semiconductor in batteries, for plating and other chemical and medical applications. There is a lack of available information about the adverse effects of indium compounds on aquatic organisms. Therefore, the toxic effects on systems from four trophic levels of the aquatic ecosystem were investigated. Firstly, the bacterium Vibrio fischeri, the alga Chlorella vulgaris and the cladoceran Daphnia magna were used in the toxicological evaluation of indium nitrate. The most sensitive model was V. fischeri, with a NOAEL of 0.02 and an EC{sub 50} of 0.04 mM at 15 min. Although indium nitrate should be classified as harmful to aquatic organisms, it is not expected to represent acute risk to the aquatic biota. Secondly, PLHC-1 fish cell line was employed to investigate the effects and mechanisms of toxicity. Although protein content, neutral red uptake, methylthiazol metabolization, lysosomal function and acetylcholinesterase activity were reduced in cells, stimulations were observed for metallothionein levels and succinate dehydrogenase and glucose-6-phosphate dehydrogenase activities. No changes were observed in ethoxyresorufin-O-deethylase activity. To clarify the main events in PLHC-1 cell death induced by indium nitrate, nine modulators were applied. They were related to oxidative stress ({alpha}-tocopherol succinate, mannitol and sodium benzoate), disruption of calcium homeostasis (BAPTA-AM and EGTA), thiol protection (1,4-dithiotreitol), iron chelation (deferoxiamine) or regulation of glutathione levels (2-oxothiazolidine-4-carboxylic acid and malic acid diethyl ester). The main morphological alterations were hydropic degeneration and loss of cells. At least, in partly, toxicity seems to be mediated by oxidative stress, and particularly by NADPH-dependent lipid peroxidation.

  5. Toxicological assessment of indium nitrate on aquatic organisms and investigation of the effects on the PLHC-1 fish cell line

    International Nuclear Information System (INIS)

    Zurita, Jorge L.; Jos, Angeles; Peso, Ana del; Salguero, Manuel; Camean, Ana M.; Lopez-Artiguez, Miguel; Repetto, Guillermo

    2007-01-01

    Indium nitrate is mainly used as a semiconductor in batteries, for plating and other chemical and medical applications. There is a lack of available information about the adverse effects of indium compounds on aquatic organisms. Therefore, the toxic effects on systems from four trophic levels of the aquatic ecosystem were investigated. Firstly, the bacterium Vibrio fischeri, the alga Chlorella vulgaris and the cladoceran Daphnia magna were used in the toxicological evaluation of indium nitrate. The most sensitive model was V. fischeri, with a NOAEL of 0.02 and an EC 50 of 0.04 mM at 15 min. Although indium nitrate should be classified as harmful to aquatic organisms, it is not expected to represent acute risk to the aquatic biota. Secondly, PLHC-1 fish cell line was employed to investigate the effects and mechanisms of toxicity. Although protein content, neutral red uptake, methylthiazol metabolization, lysosomal function and acetylcholinesterase activity were reduced in cells, stimulations were observed for metallothionein levels and succinate dehydrogenase and glucose-6-phosphate dehydrogenase activities. No changes were observed in ethoxyresorufin-O-deethylase activity. To clarify the main events in PLHC-1 cell death induced by indium nitrate, nine modulators were applied. They were related to oxidative stress (α-tocopherol succinate, mannitol and sodium benzoate), disruption of calcium homeostasis (BAPTA-AM and EGTA), thiol protection (1,4-dithiotreitol), iron chelation (deferoxiamine) or regulation of glutathione levels (2-oxothiazolidine-4-carboxylic acid and malic acid diethyl ester). The main morphological alterations were hydropic degeneration and loss of cells. At least, in partly, toxicity seems to be mediated by oxidative stress, and particularly by NADPH-dependent lipid peroxidation

  6. The combined use of the PLHC-1 cell line and the recombinant yeast assay to assess the environmental quality of estuarine and coastal sediments.

    Science.gov (United States)

    Schnell, Sabine; Olivares, Alba; Piña, Benjamin; Echavarri-Erasun, Beatriz; Lacorte, Silvia; Porte, Cinta

    2013-12-15

    Sediment contamination poses a potential risk for both ecosystems and human health. Risk assessment is troublesome as sediments contain complex mixtures of toxicants, and traditional chemical analyses can neither provide information about potential hazards to organisms nor identify and measure all present contaminants. This work combines the use of the PLHC-1 cell line and the recombinant yeast assay (RYA) to assess the environmental quality of estuarine and coastal sediments. The application of multiple endpoints (cytotoxicity, generation of oxidative stress, presence of CYP1A inducing agents, micronucleus formation and estrogenicity) revealed that the organic extracts of those sediments affected by industrial activities or collected near harbours and untreated urban discharges showed significant cytotoxicity, micronuclei and CYP1A induction. The study highlights the usefulness of the applied bioassays to identify those sediments that could pose risk to aquatic organisms and that require further action to improve their environmental quality. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Ecotoxicological properties of ketoprofen and the S(+)-enantiomer (dexketoprofen): Bioassays in freshwater model species and biomarkers in fish PLHC-1 cell line.

    Science.gov (United States)

    Mennillo, Elvira; Arukwe, Augustine; Monni, Gianfranca; Meucci, Valentina; Intorre, Luigi; Pretti, Carlo

    2018-01-01

    The increased use of nonsteroidal anti-inflammatory drugs (NSAIDs) has resulted in their ubiquitous presence in the environment. The toxicological properties of these 2 widely prescribed NSAIDs, namely racemic ketoprofen and its enantiomer S(+)-ketoprofen (dexketoprofen), were evaluated, firstly, by acute and chronic toxicity tests using 3 representative model organisms (Vibrio fischeri, Pseudokirchneriella subcapitata, and Ceriodaphnia dubia) and, secondly, by evaluating the responses of biotransformation systems and multidrug resistance-associated proteins (MRP1/MRP2) using the Poeciliopsis lucida hepatocellular carcinoma 1 (PLHC-1) fish hepatic cell line. Toxicity data from both acute and chronic dexketoprofen exposure indicated higher sensitivity through inhibition of bioluminescence and algal growth and through increased mortality/immobilization compared to racemic ketoprofen exposure. The growth inhibition test showed that racemic ketoprofen and dexketoprofen exhibited different effect concentration values (240.2 and 65.6 μg/L, respectively). Furthermore, racemic ketoprofen and dexketoprofen did not exert cytotoxic effects in PLHC-1 cells and produced compound-, time-, and concentration-specific differential effects on cytochrome P450 1A (CYP1A) and glutathione S-transferase levels. For CYP1A, the effects of racemic ketoprofen and dexketoprofen differed at the transcriptional and catalytic levels. Exposure to racemic ketoprofen and dexketoprofen modulated MRP1 and MRP2 mRNA levels, and these effects were also dependent on compound, exposure time, and concentration of the individual drug. The present study revealed for the first time the interactions between these NSAIDs and key detoxification systems and different sensitivity to the racemic mixture compared to its enantiomer. Environ Toxicol Chem 2018;37:201-212. © 2017 SETAC. © 2017 SETAC.

  8. Reverting doxorubicin resistance in colon cancer by targeting a key signaling protein, steroid receptor coactivator.

    Science.gov (United States)

    Xiong, Sang; Xiao, Gong-Wei

    2018-04-01

    Although there have been notable improvements in treatments against cancer, further research is required. In colon cancer, nearly all patients eventually experience drug resistance and stop responding to the approved drugs, making treatment difficult. Steroid receptor coactivator (SRC) is an oncogenic nuclear receptor coactivator that serves an important role in drug resistance. The present study generated a doxorubicin-resistant colon cancer cell line, in which the upregulation/activation of SRC was responsible for drug resistance, which in turn activated AKT. Overexpression of receptor tyrosine kinase-like epidermal growth factor receptor and insulin-like growth factor 1 receptor also induced SRC expression. It was observed that doxorubicin resistance in colon cancer also induced epithelial to mesenchymal transition, a decrease in expression of epithelial marker E-cadherin and an increase in the expression of mesenchymal markers, including N-cadherin and vimentin. Additionally, the present study indicated that SRC acts as a common signaling node, and inhibiting SRC in combination with doxorubicin treatment in doxorubicin-resistant cells aids in reversing the resistance. Thus, the present study suggests that activation of SRC is responsible for doxorubicin resistance in colon cancer. However, further research is required to understand the complete mechanism of how drug resistance occurs and how it may be tackled to treat patients.

  9. Potentiating effect of graphene nanomaterials on aromatic environmental pollutant-induced cytochrome P450 1A expression in the topminnow fish hepatoma cell line PLHC-1.

    Science.gov (United States)

    Lammel, Tobias; Boisseaux, Paul; Navas, José M

    2015-09-01

    Graphene and its derivatives are an emerging class of carbon nanomaterial with great potential for a broad range of industrial and consumer applications. However, their increasing production and use is expected to result in release of nano-sized graphene platelets into the environment, where they may interact with chemical pollutants modifying their fate and toxic potential. The objective of this study was to assess whether graphene nanoplatelets can act as vector for aromatic environmental pollutants increasing their cellular uptake and associated hazardous effects in vitro. For this purpose, cell cultures of the topminnow fish (Poeciliopsis lucida) hepatoma cell line PLHC-1 were simultaneously (and successively) exposed to graphene nanoplatelets (graphene oxide (GO) or carboxyl graphene (CXYG)) and an aryl hydrocarbon receptor (AhR) agonist (β-naphthoflavone (β-NF), benzo(k)fluoranthene (BkF) or 3,3',4,4',5,5'-hexachlorobiphenyl (PCB169)). Following exposure cytochrome P450 1A (Cyp1A) induction was assessed by measuring cyp1A mRNA expression levels using reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) and Cyp1A-dependent ethoxyresorufin-O-deethylase (EROD) activity. It was observed that pre- and co-exposure of cells to GO and CXYG nanoplatelets had a potentiating effect on β-NF, BkF, and PCB169-dependent Cyp1A induction suggesting that graphene nanoplatelets increase the effective concentration of AhR agonists by facilitating their passive diffusion into the cells by damaging the cells' plasma membrane and/or by transporting them over the plasma membrane via a Trojan horse-like mechanism. The results demonstrate the existence of combination effects between nanomaterials and environmental pollutants and stress the importance of considering these effects when evaluating their respective hazard. © 2014 Wiley Periodicals, Inc.

  10. Sulfur amino acid metabolism in doxorubicin-resistant breast cancer cells

    International Nuclear Information System (INIS)

    Ryu, Chang Seon; Kwak, Hui Chan; Lee, Kye Sook; Kang, Keon Wook; Oh, Soo Jin; Lee, Ki Ho; Kim, Hwan Mook; Ma, Jin Yeul; Kim, Sang Kyum

    2011-01-01

    Although methionine dependency is a phenotypic characteristic of tumor cells, it remains to be determined whether changes in sulfur amino acid metabolism occur in cancer cells resistant to chemotherapeutic medications. We compared expression/activity of sulfur amino acid metabolizing enzymes and cellular levels of sulfur amino acids and their metabolites between normal MCF-7 cells and doxorubicin-resistant MCF-7 (MCF-7/Adr) cells. The S-adenosylmethionine/S-adenosylhomocysteine ratio, an index of transmethylation potential, in MCF-7/Adr cells decreased to ∼ 10% relative to that in MCF-7 cells, which may have resulted from down-regulation of S-adenosylhomocysteine hydrolase. Expression of homocysteine-clearing enzymes, such as cystathionine beta-synthase, methionine synthase/methylene tetrahydrofolate reductase, and betaine homocysteine methyltransferase, was up-regulated in MCF-7/Adr cells, suggesting that acquiring doxorubicin resistance attenuated methionine-dependence and activated transsulfuration from methionine to cysteine. Homocysteine was similar, which is associated with a balance between the increased expressions of homocysteine-clearing enzymes and decreased extracellular homocysteine. Despite an elevation in cysteine, cellular GSH decreased in MCF-7/Adr cells, which was attributed to over-efflux of GSH into the medium and down-regulation of the GSH synthesis enzyme. Consequently, MCF-7/Adr cells were more sensitive to the oxidative stress induced by bleomycin and menadione than MCF-7 cells. In conclusion, our results suggest that regulating sulfur amino acid metabolism may be a possible therapeutic target for chemoresistant cancer cells. These results warrant further investigations to determine the role of sulfur amino acid metabolism in acquiring anticancer drug resistance in cancer cells using chemical and biological regulators involved in sulfur amino acid metabolism. - Research highlights: → MCF-7/Adr cells showed decreases in cellular GSH

  11. Role of aldo-keto reductases and other doxorubicin pharmacokinetic genes in doxorubicin resistance, DNA binding, and subcellular localization

    International Nuclear Information System (INIS)

    Heibein, Allan D; Guo, Baoqing; Sprowl, Jason A; MacLean, David A; Parissenti, Amadeo M

    2012-01-01

    Since proteins involved in chemotherapy drug pharmacokinetics and pharmacodynamics have a strong impact on the uptake, metabolism, and efflux of such drugs, they likely play critical roles in resistance to chemotherapy drugs in cancer patients. To investigate this hypothesis, we conducted a whole genome microarray study to identify difference in the expression of genes between isogenic doxorubicin-sensitive and doxorubicin-resistant MCF-7 breast tumour cells. We then assessed the degree of over-representation of doxorubicin pharmacokinetic and pharmacodynamic genes in the dataset of doxorubicin resistance genes. Of 27,958 Entrez genes on the array, 7.4 per cent or 2,063 genes were differentially expressed by ≥ 2-fold between wildtype and doxorubicin-resistant cells. The false discovery rate was set at 0.01 and the minimum p value for significance for any gene within the “hit list” was 0.01. Seventeen and 43 per cent of doxorubicin pharmacokinetic genes were over-represented in the hit list, depending upon whether the gene name was identical or within the same gene family, respectively. The most over-represented genes were within the 1C and 1B families of aldo-keto reductases (AKRs), which convert doxorubicin to doxorubicinol. Other genes convert doxorubicin to other metabolites or affect the influx, efflux, or cytotoxicity of the drug. In further support of the role of AKRs in doxorubicin resistance, we observed that, in comparison to doxorubicin, doxorubincol exhibited dramatically reduced cytotoxicity, reduced DNA-binding activity, and strong localization to extra nuclear lysosomes. Pharmacologic inhibition of the above AKRs in doxorubicin-resistant cells increased cellular doxorubicin levels, restored doxorubicin cytotoxicity and re-established doxorubicin localization to the nucleus. The properties of doxorubicinol were unaffected. These findings demonstrate the utility of using curated pharmacokinetic and pharmacodynamic knowledge bases to identify

  12. Xanthohumol, a Prenylated Chalcone from Hops, Inhibits the Viability and Stemness of Doxorubicin-Resistant MCF-7/ADR Cells

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    Ming Liu

    2016-12-01

    Full Text Available Xanthohumol is a unique prenylated flavonoid in hops (Humulus lupulus L. and beer. Xanthohumol has been shown to possess a variety of pharmacological activities. There is little research on its effect on doxorubicin-resistant breast cancer cells (MCF-7/ADR and the cancer stem-like cells exiting in this cell line. In the present study, we investigate the effect of xanthohumol on the viability and stemness of MCF-7/ADR cells. Xanthohumol inhibits viability, induces apoptosis, and arrests the cell cycle of MCF-7/ADR cells in a dose-dependent manner; in addition, xanthohumol sensitizes the inhibition effect of doxorubicin on MCF-7/ADR cells. Interestingly, we also find that xanthohumol can reduce the stemness of MCF-7/ADR cells evidenced by the xanthohumol-induced decrease in the colony formation, the migration, the percentage of side population cells, the sphere formation, and the down-regulation of stemness-related biomarkers. These results demonstrate that xanthohumol is a promising compound targeting the doxorubicin resistant breast cancer cells and regulating their stemness, which, therefore, will be applied as a potential candidate for the development of a doxorubicin-resistant breast cancer agent and combination therapy of breast cancer.

  13. Involvement of HIF-1α activation in the doxorubicin resistance of human osteosarcoma cells.

    Science.gov (United States)

    Roncuzzi, Laura; Pancotti, Fabia; Baldini, Nicola

    2014-07-01

    Osteosarcoma is the most common primary bone cancer in children and adolescents. Despite aggressive treatment regimens, survival outcomes remain unsatisfactory, particularly in patients with metastatic and/or recurrent disease. Unfortunately, treatment failure is commonly due to the development of chemoresistance, for which the underlying molecular mechanisms remain unclear. The aim of the present study was to investigate the role of hypoxia-inducible factor 1α (HIF‑1α) and its signalling pathways as mediators of drug-resistance in human osteosarcoma. Toward this aim, we established two osteosarcoma cell lines selected for resistance to doxorubicin, a drug of choice in the treatment of this tumour. Our results showed that the multidrug resistance (MDR) phenotype was also mediated by HIF-1α, the most important regulator of cell adaptation to hypoxia. Our data showed that this transcription factor promoted the outward transport of intracellular doxorubicin by activating the P-glycoprotein (P-gp) expression in osteosarcoma cells maintained in normoxic conditions. In addition, it hindered doxorubicin-induced apoptosis by regulating the expression of c-Myc and p21. Finally, we observed that the doxorubicin-resistant cells maintained for 2 months of continuous culture in a drug-free medium, lost their drug-resistance and this effect was associated with the absence of HIF-1α expression. The emerging role of HIF-1α in osteosarcoma biology indicates its use as a valuable therapeutic target.

  14. Indomethacin induces apoptosis via a MRPI-dependent mechanism in doxorubicin-resistant small-cell lung cancer cells overexpressing MRPI

    NARCIS (Netherlands)

    de Groot, D. J. A.; van der Deen, M.; Le, T. K. P.; Regeling, A.; de Jong, S.; de Vries, E. G. E.

    2007-01-01

    Small-cell lung cancers (SCLCs) initially respond to chemotherapy, but are often resistant at recurrence. The non-steroidal anti-inflammatory drug indomethacin is an inhibitor of multidrug resistance protein 1 (MRPI) function. The doxorubicin-resistant MRPI-overexpressing human SCLC cell line

  15. Anti-cancer effect of oncolytic adenovirus-armed shRNA targeting MYCN gene on doxorubicin-resistant neuroblastoma cells.

    Science.gov (United States)

    Li, Yuan; Zhuo, Baobiao; Yin, Yiyu; Han, Tao; Li, Shixian; Li, Zhengwei; Wang, Jian

    2017-09-09

    Chemotherapy is one of the few effective choices for patients with neuroblastoma. However, the development of muti-drug resistance (MDR) to chemotherapy is a major obstacle to the effective treatment of advanced or recurrent neuroblastoma. The muti-drug resistance-associated protein (MRP), which encodes a transmembrane glycoprotein, is a key regulator of MDR. The expression of MRP is a close correlation with MYCN oncogene in neuroblastoma. We have recently shown ZD55-shMYCN (oncolytic virus armed with shRNA against MYCN) can down-regulate MYCN to inhibit tumor cells proliferation and induce apoptosis in neuroblastoma. Here we further report ZD55-shMYCN re-sensitized doxorubicin-resistant cells to doxorubicin (as shown by reduced proliferation, increased apoptosis, and inhibited cell migration), and reduced the in vivo growth rate of neuroblastoma xenografts by down-regulation of MRP expression. Sequential therapy with doxorubicin did not affect the replication of ZD55-shMYCN in doxorubicin-resistant neuroblastoma cells, but decreased the expression of Bcl-2, Bcl-X L , MMP-1. Thus, this synergistic effect of ZD55-shMYCN in combination with doxorubicin provides a novel therapy strategy for doxorubicin-resistant neuroblastoma, and is a promising approach for further clinical development. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Modulation of DNA methylation levels sensitizes doxorubicin-resistant breast adenocarcinoma cells to radiation-induced apoptosis

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    Luzhna, Lidia [Department of Biological Sciences, University of Lethbridge, AB, Canada T1K 3M4 (Canada); Kovalchuk, Olga, E-mail: olga.kovalchuk@uleth.ca [Department of Biological Sciences, University of Lethbridge, AB, Canada T1K 3M4 (Canada)

    2010-02-05

    Chemoresistant tumors often fail to respond to other cytotoxic treatments such as radiation therapy. The mechanisms of chemo- and radiotherapy cross resistance are not fully understood and are believed to be epigenetic in nature. We hypothesize that MCF-7 cells and their doxorubicin-resistant variant MCF-7/DOX cells may exhibit different responses to ionizing radiation due to their dissimilar epigenetic status. Similar to previous studies, we found that MCF-7/DOX cells harbor much lower levels of global DNA methylation than MCF-7 cells. Furthermore, we found that MCF-7/DOX cells had lower background apoptosis levels and were less responsive to radiation than MCF-7 cells. Decreased radiation responsiveness correlated to significant global DNA hypomethylation in MCF-7/DOX cells. Here, for the first time, we show that the radiation resistance of MCF-7/DOX cells can be reversed by an epigenetic treatment - the application of methyl-donor SAM. SAM-mediated reversal of DNA methylation led to elevated radiation sensitivity in MCF-7/DOX cells. Contrarily, application of SAM on the radiation sensitive and higher methylated MCF-7 cells resulted in a decrease in their radiation responsiveness. This data suggests that a fine balance of DNA methylation is needed to insure proper radiation and drug responsiveness.

  17. p-Glycoprotein ABCB5 and YB-1 expression plays a role in increased heterogeneity of breast cancer cells: correlations with cell fusion and doxorubicin resistance

    International Nuclear Information System (INIS)

    Yang, Ji Yeon; Ha, Seon-Ah; Yang, Yun-Sik; Kim, Jin Woo

    2010-01-01

    Cancer cells recurrently develop into acquired resistance to the administered drugs. The iatrogenic mechanisms of induced chemotherapy-resistance remain elusive and the degree of drug resistance did not exclusively correlate with reductions of drug accumulation, suggesting that drug resistance may involve additional mechanisms. Our aim is to define the potential targets, that makes drug-sensitive MCF-7 breast cancer cells turn to drug-resistant, for the anti-cancer drug development against drug resistant breast cancer cells. Doxorubicin resistant human breast MCF-7 clones were generated. The doxorubicin-induced cell fusion events were examined. Heterokaryons were identified and sorted by FACS. In the development of doxorubicin resistance, cell-fusion associated genes, from the previous results of microarray, were verified using dot blot array and quantitative RT-PCR. The doxorubicin-induced expression patterns of pro-survival and pro-apoptotic genes were validated. YB-1 and ABCB5 were up regulated in the doxorubicin treated MCF-7 cells that resulted in certain degree of genomic instability that accompanied by the drug resistance phenotype. Cell fusion increased diversity within the cell population and doxorubicin resistant MCF-7 cells emerged probably through clonal selection. Most of the drug resistant hybrid cells were anchorage independent. But some of the anchorage dependent MCF-7 cells exhibited several unique morphological appearances suggesting minor population of the fused cells maybe de-differentiated and have progenitor cell like characteristics. Our work provides valuable insight into the drug induced cell fusion event and outcome, and suggests YB-1, GST, ABCB5 and ERK3 could be potential targets for the anti-cancer drug development against drug resistant breast cancer cells. Especially, the ERK-3 serine/threonine kinase is specifically up-regulated in the resistant cells and known to be susceptible to synthetic antagonists

  18. Epstein-Barr virus EBNA2 directs doxorubicin resistance of B cell lymphoma through CCL3 and CCL4-mediated activation of NF-κB and Btk.

    Science.gov (United States)

    Kim, Joo Hyun; Kim, Won Seog; Hong, Jung Yong; Ryu, Kung Ju; Kim, Seok Jin; Park, Chaehwa

    2017-01-17

    Epstein-Barr virus (EBV)-encoded nuclear antigen, EBNA2, expressed in EBV-infected B lymphocytes is critical for lymphoblastoid cell growth. Microarray profiling and cytokine array screening revealed that EBNA2 is associated with upregulation of the chemokines CCL3 and CCL4 in lymphoma cells. Depletion or inactivation of CCL3 or CCL4 sensitized DLBCL cells to doxorubicin. Our results indicate that EBV influences cell survival via an autocrine mechanism whereby EBNA2 increases CCL3 and CCL4, which in turn activate the Btk and NF-κB pathways, contributing to doxorubicin resistance of B lymphoma cells. Western blot data further confirmed that CCL3 and CCL4 direct activation of Btk and NF-κB. Based on these findings, we propose that a pathway involving EBNA2/Btk/NF-κB/CCL3/CCL4 plays a key role in doxorubicin resistance, and therefore, inhibition of specific components of this pathway may sensitize lymphoma cells to doxorubicin. Evaluation of the relationship between CCL3 expression and EBV infection revealed high CCL3 levels in EBV-positive patients. Our data collectively suggest that doxorubicin treatment for EBNA2-positive DLBCL cells may be effectively complemented with a NF-κB or Btk inhibitor. Moreover, evaluation of the CCL3 and CCL4 levels may be helpful for selecting DLBCL patients likely to benefit from doxorubicin treatment in combination with the velcade or ibrutinib.

  19. Furanodiene Induces Extrinsic and Intrinsic Apoptosis in Doxorubicin-Resistant MCF-7 Breast Cancer Cells via NF-κB-Independent Mechanism.

    Science.gov (United States)

    Zhong, Zhang-Feng; Yu, Hai-Bing; Wang, Chun-Ming; Qiang, Wen-An; Wang, Sheng-Peng; Zhang, Jin-Ming; Yu, Hua; Cui, Liao; Wu, Tie; Li, De-Qiang; Wang, Yi-Tao

    2017-01-01

    Chemotherapy is used as a primary approach in cancer treatment after routine surgery. However, chemo-resistance tends to occur when chemotherapy is used clinically, resulting in poor prognosis and recurrence. Currently, Chinese medicine may provide insight into the design of new therapies to overcome chemo-resistance. Furanodiene, as a heat-sensitive sesquiterpene, is isolated from the essential oil of Rhizoma Curcumae . Even though mounting evidence claiming that furanodiene possesses anti-cancer activities in various types of cancers, the underlying mechanisms against chemo-resistant cancer are not fully clear. Our study found that furanodiene could display anti-cancer effects by inhibiting cell viability, inducing cell cytotoxicity, and suppressing cell proliferation in doxorubicin-resistant MCF-7 breast cancer cells. Furthermore, furanodiene preferentially causes apoptosis by interfering with intrinsic/extrinsic-dependent and NF-κB-independent pathways in doxorubicin-resistant MCF-7 cells. These observations also prompt that furanodiene may be developed as a promising natural product for multidrug-resistant cancer therapy in the future.

  20. A novel copper complex induces ROS generation in doxorubicin resistant Ehrlich ascitis carcinoma cells and increases activity of antioxidant enzymes in vital organs in vivo

    International Nuclear Information System (INIS)

    Mookerjee, Ananda; Roy, Syamal; Choudhuri, Soumitra K; Basu, Jayati Mookerjee; Majumder, Surajit; Chatterjee, Shilpak; Panda, Gouri S; Dutta, Pranabananda; Pal, Smarajit; Mukherjee, Pratima; Efferth, Thomas

    2006-01-01

    In search of a suitable GSH-depleting agent, a novel copper complex viz., copper N-(2-hydroxyacetophenone) glycinate (CuNG) has been synthesized, which was initially found to be a potential resistance modifying agent and later found to be an immunomodulator in mice model in different doses. The objective of the present work was to decipher the effect of CuNG on reactive oxygen species (ROS) generation and antioxidant enzymes in normal and doxorubicin-resistant Ehrlich ascites carcinoma (EAC/Dox)-bearing Swiss albino mice. The effect of CuNG has been studied on ROS generation, multidrug resistance-associated protein1 (MRP1) expression and on activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). CuNG increased ROS generation and reduced MRP1 expression in EAC/Dox cells while only temporarily depleted glutathione (GSH) within 2 h in heart, kidney, liver and lung of EAC/Dox bearing mice, which were restored within 24 h. The level of liver Cu was observed to be inversely proportional to the level of GSH. Moreover, CuNG modulated SOD, CAT and GPx in different organs and thereby reduced oxidative stress. Thus nontoxic dose of CuNG may be utilized to reduce MRP1 expression and thus sensitize EAC/Dox cells to standard chemotherapy. Moreover, CuNG modulated SOD, CAT and and GPx activities to reduce oxidative stress in some vital organs of EAC/Dox bearing mice. CuNG treatment also helped to recover liver and renal function in EAC/Dox bearing mice. Based on our studies, we conclude that CuNG may be a promising candidate to sensitize drug resistant cancers in the clinic

  1. Ganoderma tsugae Induces S Phase Arrest and Apoptosis in Doxorubicin-Resistant Lung Adenocarcinoma H23/0.3 Cells via Modulation of the PI3K/Akt Signaling Pathway

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    Yang-Hao Yu

    2012-01-01

    Full Text Available Ganoderma tsugae (GT is a traditional Chinese medicine that exhibits significant antitumor activities against many types of cancer. This study investigated the molecular mechanism by which GT suppresses the growth of doxorubicin-resistant lung adenocarcinoma H23/0.3 cells. Our results reveal that GT inhibits the viability of H23/0.3 cells in vitro and in vivo and sensitizes the growth suppression effect of doxorubicin on H23/0.3 cells. The data also show that GT induces S phase arrest by interfering with the protein expression of cyclin A, cyclin E, CDK2, and CDC25A. Furthermore, GT induces cellular apoptosis via induction of a mitochondria/caspase pathway. In addition, we also demonstrate that the suppression of cell proliferation by GT is through down-regulation of the PI3K/Akt signaling pathway. In conclusion, this study suggests that GT may be a useful adjuvant therapeutic agent in the treatment of lung cancer.

  2. The combination of temozolomide-irinotecan regresses a doxorubicin-resistant patient-derived orthotopic xenograft (PDOX) nude-mouse model of recurrent Ewing's sarcoma with a FUS-ERG fusion and CDKN2A deletion: Direction for third-line patient therapy.

    Science.gov (United States)

    Miyake, Kentaro; Murakami, Takashi; Kiyuna, Tasuku; Igarashi, Kentaro; Kawaguchi, Kei; Miyake, Masuyo; Li, Yunfeng; Nelson, Scott D; Dry, Sarah M; Bouvet, Michael; Elliott, Irmina A; Russell, Tara A; Singh, Arun S; Eckardt, Mark A; Hiroshima, Yukihiko; Momiyama, Masashi; Matsuyama, Ryusei; Chishima, Takashi; Endo, Itaru; Eilber, Fritz C; Hoffman, Robert M

    2017-11-28

    The aim of the present study was to determine the usefulness of a patient-derived orthotopic xenograft (PDOX) nude-mouse model of a doxorubicin-resistant metastatic Ewing's sarcoma, with a unique combination of a FUS-ERG fusion and CDKN2A deletion, to identify effective drugs for third-line chemotherapy of the patient. Our previous study showed that cyclin-dependent kinase 4/6 (CDK4/6) and insulin-like growth factor-1 receptor (IGF-1R) inhibitors were effective on the Ewing's sarcoma PDOX, but not doxorubicin, similar to the patient's resistance to doxorubicin. The results of the previous PDOX study were successfully used for second-line therapy of the patiend. In the present study, the PDOX mice established with the Ewing's sarcoma in the right chest wall were randomized into 5 groups when the tumor volume reached 60 mm 3 : untreated control; gemcitabine combined with docetaxel (intraperitoneal [i.p.] injection, weekly, for 2 weeks); irinotecan combined with temozolomide (irinotecan: i.p. injection; temozolomide: oral administration, daily, for 2 weeks); pazopanib (oral administration, daily, for 2 weeks); yondelis (intravenous injection, weekly, for 2 weeks). All mice were sacrificed on day 15. Body weight and tumor volume were assessed 2 times per week. Tumor weight was measured after sacrifice. Irinotecan combined with temozolomide was the most effective regimen compared to the untreated control group (p=0.022). Gemcitabine combined with docetaxel was also effective (p=0.026). Pazopanib and yondelis did not have significant efficacy compared to the untreated control (p=0.130, p=0.818). These results could be obtained within two months after the physician's request and were used for third-line therapy of the patient.

  3. Organic Isothiocyanates: Dietary Modulators of Doxorubicin Resistance in Breast Cancer

    Science.gov (United States)

    2004-06-01

    activation (16). In addition, ITCs can study, the compounds were ineffective at a concentration of induce phase II enzymes responsible for the...over 50% of drugs in clinical use including erythromycin, been reported in women as a result of higher alcohol lidocaine , and midazolam and is also

  4. Circumvention of resistance to photodynamic therapy in doxorubicin-resistant sarcoma by photochemical internalization of gelonin.

    Science.gov (United States)

    Olsen, Cathrine Elisabeth; Berg, Kristian; Selbo, Pål Kristian; Weyergang, Anette

    2013-12-01

    A wide range of anti-cancer therapies have been shown to induce resistance upon repetitive treatment and such adapted resistance may also cause cross-resistance to other treatment modalities. We here show that MES-SA/Dx5 cells with adapted resistance to doxorubicin (DOX) are cross-resistant to photodynamic therapy (PDT). A DOX-induced increased expression of the reactive oxygen species (ROS)-scavenging proteins glutathione peroxidase (GPx) 1 and GPx4 in MES-SA/Dx5 cells was indicated as the mechanism of resistance to PDT in line with the reduction in PDT-generated ROS observed in this cell line. ROS-induced p38 activation was, in addition, shown to be reduced to one-third of the signal of the parental MES-SA cells 2h after PDT, and addition of the p38 inhibitor SB203580 confirmed p38 activation as a death signal after PDT in the MES-SA cells. The MES-SA/Dx5 cells were also cross-resistant to ionizing radiation in agreement with the increased GPx1 and GPx4 expression. Surprisingly, PDT-induced endo/lysosomal release of the ribosome-inactivating protein gelonin (photochemical internalization (PCI)) was more effective in the PDT-resistant MES-SA/Dx5 cells, as measured by synergy calculations in both cell lines. Analysis of death-inducing signaling indicated a low activation of caspase-3 and a strong PARP I cleavage after PDT and PCI in both cell lines. The PARP I activation was, however, stronger after PCI than after PDT in the MES-SA cells, but not in the MES-SA/Dx5 cells, and therefore cannot explain the strong PCI effect in the MES-SA/Dx5 cells. In conclusion PCI of recombinant gelonin circumvents ROS resistance in an apoptosis-independent manner. © 2013 Elsevier Inc. All rights reserved.

  5. The lipid content of cisplatin- and doxorubicin-resistant MCF-7 human breast cancer cells.

    Science.gov (United States)

    Todor, I N; Lukyanova, N Yu; Chekhun, V F

    2012-07-01

    To perform the comparative study both of qualitative and quantitative content of lipids in parental and drug resistant breast cancer cells. Parental (MCF-7/S) and resistant to cisplatin (MCF-7/CP) and doxorubicin (MCF-7/Dox) human breast cancer cells were used in the study. Cholesterol, total lipids and phospholipids content were determined by means of thin-layer chromatography. It was found that cholesterol as well as cholesterol ethers content are significantly higher but diacylglycerols, triacyl-glycerols content are significantly lower in resistant cell strains than in parental (sensitive) cells. Moreover the analysis of individual phospholipids showed the increase of sphingomyelin, phosphatidylserine, cardiolipin, phosphatidic acid and the decrease of phosphatidy-lethanolamine, phosphatidylcholine in MCF-7/CP and MCF-7/Dox cells. Obtained results allow to suggest that the lipid profile changes can mediate the modulation of membrane fluidity in drug resistant MCF-7 breast cancer cells.

  6. Downregulation of CD44 reduces doxorubicin resistance of CD44+CD24- breast cancer cells

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    Phuc PV

    2011-06-01

    Full Text Available Pham Van Phuc, Phan Lu Chinh Nhan, Truong Hai Nhung, Nguyen Thanh Tam, Nguyen Minh Hoang, Vuong Gia Tue, Duong Thanh Thuy, Phan Kim NgocLaboratory of Stem Cell Research and Application, University of Science, Vietnam National University, Ho Chi Minh, VietnamBackground: Cells within breast cancer stem cell populations have been confirmed to have a CD44+CD24- phenotype. Strong expression of CD44 plays a critical role in numerous types of human cancers. CD44 is involved in cell differentiation, adhesion, and metastasis of cancer cells.Methods: In this study, we reduced CD44 expression in CD44+CD24- breast cancer stem cells and investigated their sensitivity to an antitumor drug. The CD44+CD24- breast cancer stem cells were isolated from breast tumors; CD44 expression was downregulated with siRNAs followed by treatment with different concentrations of the antitumor drug.Results: The proliferation of CD44 downregulated CD44+CD24- breast cancer stem cells was decreased after drug treatment. We noticed treated cells were more sensitive to doxorubicin, even at low doses, compared with the control groups.Conclusions: It would appear that expression of CD44 is integral among the CD44+CD24- cell population. Reducing the expression level of CD44, combined with doxorubicin treatment, yields promising results for eradicating breast cancer stem cells in vitro. This study opens a new direction in treating breast cancer through gene therapy in conjunction with chemotherapy.Keywords: antitumor drugs, breast cancer stem cells, CD44, CD44+CD24- cells, doxorubicin

  7. Abnormally banded chromosomal regions in doxorubicin-resistant B16-BL6 murine melanoma cells.

    Science.gov (United States)

    Slovak, M L; Hoeltge, G A; Ganapathi, R

    1986-08-01

    B16-BL6 murine melanoma cells were selected for cytogenetic evaluation during the stepwise development of increasing resistance in vitro to the antitumor antibiotic, doxorubicin (DOX). Karyotypic studies demonstrated extensive heteroploidy with both numerical and structural abnormalities which were not present in the parental DOX-sensitive B16-BL6 cells. Trypsin-Giemsa banding revealed the presence of several marker chromosomes containing abnormally banding regions (ABRs) in the 44-fold B16-BL6 DOX-resistant subline. These ABRs appeared to be more homogeneously staining at the higher DOX concentrations. Length measurements (ABR index) in seven banded metaphases indicated a direct correlation with increasing DOX concentration. When the DOX-resistant cells were grown in drug-free medium for 1 yr, the drug-resistant phenotype gradually declined in parallel with the level of resistance and the ABR index. DOX-induced cytogenetic damage examined by sister chromatid exchange methodology in parental B16-BL6 cells indicated a linear sister chromatid exchange:DOX dose-response relationship. However, after continuous treatment of parental B16-BL6 cells with DOX (0.01 microgram/ml) for 30 days, sister chromatid exchange scores were found to return to base-line values. The B16-BL6 resistant cells demonstrated a cross-resistant phenotype with N-trifluoroacetyladriamycin-14-valerate, actinomycin D, and the Vinca alkaloids but not with 1-beta-D-arabinofuranosylcytosine. The results suggest that ABR-containing chromosomes in DOX-resistant sublines may represent cytogenetic alterations of specific amplified genes involved in the expression of DOX resistance. Further studies are required to identify and define the possible gene products and to correlate their relationship to the cytotoxic action of doxorubicin.

  8. Anti-cancer effect of HIV-1 viral protein R on doxorubicin resistant neuroblastoma.

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    Richard Y Zhao

    Full Text Available Several unique biological features of HIV-1 Vpr make it a potentially powerful agent for anti-cancer therapy. First, Vpr inhibits cell proliferation by induction of cell cycle G2 arrest. Second, it induces apoptosis through multiple mechanisms, which could be significant as it may be able to overcome apoptotic resistance exhibited by many cancerous cells, and, finally, Vpr selectively kills fast growing cells in a p53-independent manner. To demonstrate the potential utility of Vpr as an anti-cancer agent, we carried out proof-of-concept studies in vitro and in vivo. Results of our preliminary studies demonstrated that Vpr induces cell cycle G2 arrest and apoptosis in a variety of cancer types. Moreover, the same Vpr effects could also be detected in some cancer cells that are resistant to anti-cancer drugs such as doxorubicin (DOX. To further illustrate the potential value of Vpr in tumor growth inhibition, we adopted a DOX-resistant neuroblastoma model by injecting SK-N-SH cells into C57BL/6N and C57BL/6J-scid/scid mice. We hypothesized that Vpr is able to block cell proliferation and induce apoptosis regardless of the drug resistance status of the tumors. Indeed, production of Vpr via adenoviral delivery to neuroblastoma cells caused G2 arrest and apoptosis in both drug naïve and DOX-resistant cells. In addition, pre-infection or intratumoral injection of vpr-expressing adenoviral particles into neuroblastoma tumors in SCID mice markedly inhibited tumor growth. Therefore, Vpr could possibly be used as a supplemental viral therapeutic agent for selective inhibition of tumor growth in anti-cancer therapy especially when other therapies stop working.

  9. APC loss in breast cancer leads to doxorubicin resistance via STAT3 activation.

    Science.gov (United States)

    VanKlompenberg, Monica K; Leyden, Emily; Arnason, Anne H; Zhang, Jian-Ting; Stefanski, Casey D; Prosperi, Jenifer R

    2017-11-28

    Resistance to chemotherapy is one of the leading causes of death from breast cancer. We recently established that loss of Adenomatous Polyposis Coli (APC) in the Mouse Mammary Tumor Virus - Polyoma middle T (MMTV-PyMT) transgenic mouse model results in resistance to cisplatin or doxorubicin-induced apoptosis. Herein, we aim to establish the mechanism that is responsible for APC-mediated chemotherapeutic resistance. Our data demonstrate that MMTV-PyMT; Apc Min/+ cells have increased signal transducer and activator of transcription 3 (STAT3) activation. STAT3 can be constitutively activated in breast cancer, maintains the tumor initiating cell (TIC) population, and upregulates multidrug resistance protein 1 (MDR1). The activation of STAT3 in the MMTV-PyMT; Apc Min/+ model is independent of interleukin 6 (IL-6); however, enhanced EGFR expression in the MMTV-PyMT; Apc Min/+ cells may be responsible for the increased STAT3 activation. Inhibiting STAT3 with a small molecule inhibitor A69 in combination with doxorubicin, but not cisplatin, restores drug sensitivity. A69 also decreases doxorubicin enhanced MDR1 gene expression and the TIC population enhanced by loss of APC. In summary, these results have revealed the molecular mechanisms of APC loss in breast cancer that can guide future treatment plans to counteract chemotherapeutic resistance.

  10. Quercetin-Based Modified Porous Silicon Nanoparticles for Enhanced Inhibition of Doxorubicin-Resistant Cancer Cells.

    Science.gov (United States)

    Liu, Zehua; Balasubramanian, Vimalkumar; Bhat, Chinmay; Vahermo, Mikko; Mäkilä, Ermei; Kemell, Marianna; Fontana, Flavia; Janoniene, Agne; Petrikaite, Vilma; Salonen, Jarno; Yli-Kauhaluoma, Jari; Hirvonen, Jouni; Zhang, Hongbo; Santos, Hélder A

    2017-02-01

    One of the most challenging obstacles in nanoparticle's surface modification is to achieve the concept that one ligand can accomplish multiple purposes. Upon such consideration, 3-aminopropoxy-linked quercetin (AmQu), a derivative of a natural flavonoid inspired by the structure of dopamine, is designed and subsequently used to modify the surface of thermally hydrocarbonized porous silicon (PSi) nanoparticles. This nanosystem inherits several advanced properties in a single carrier, including promoted anticancer efficiency, multiple drug resistance (MDR) reversing, stimuli-responsive drug release, drug release monitoring, and enhanced particle-cell interactions. The anticancer drug doxorubicin (DOX) is efficiently loaded into this nanosystem and released in a pH-dependent manner. AmQu also effectively quenches the fluorescence of the loaded DOX, thereby allowing the use of the nanosystem for monitoring the intracellular drug release. Furthermore, a synergistic effect with the presence of AmQu is observed in both normal MCF-7 and DOX-resistant MCF-7 breast cancer cells. Due to the similar structure as dopamine, AmQu may facilitate both the interaction and internalization of PSi into the cells. Overall, this PSi-based platform exhibits remarkable superiority in both multifunctionality and anticancer efficiency, making this nanovector a promising system for anti-MDR cancer treatment. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Experimental and Simulation Identification of Xanthohumol as an Inhibitor and Substrate of ABCB1

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    Fangming Liu

    2018-04-01

    Full Text Available Xanthohumol (XN is a well-known prenylated flavonoid found in Humulus lupulus L. It is involved in several pharmacological activities, including the sensitization of doxorubicin-resistant breast cancer (MCF-7/ADR cells to doxorubicin (DOX through a reduction in cell viability and stemness. In the present study, we revealed another mechanism to further explain the reverse of the drug resistance of XN. In the MCF-7/ADR cell line, we found that XN inhibited the efflux functions of ATP-binding cassette subfamily B member 1 (ABCB1. We also observed that XN was a substrate of ABCB1 and stimulated its ATPase activity. Moreover, our results revealed that XN showed a synergic effect with the ABCB1 substrate colchicine (COL in the MCF-7/ADR cell line. Further, we showed that XN bound to the central transmembrane domain (TMD site, overlapping with the DOX binding site. This mechanism was supported by molecular modeling and simulation data, which revealed that XN bound to the ABCB1 transmembrane domain, where doxorubicin also binds, and its binding affinity was stronger than that of doxorubicin, resulting in less protein and ligand position fluctuation. These results support the XN-induced reversal of drug resistance via the inhibition of ABCB1-mediated transport of doxorubicin, stimulating ABCB1 ATPase activity and acting as a substrate of ABCB1.

  12. Comparative Study of Different Nano-Formulations of Curcumin for Reversal of Doxorubicin Resistance in K562R Cells.

    Science.gov (United States)

    Dash, Tapan K; Konkimalla, V Badireenath

    2017-02-01

    Curcumin is very well established as a chemo-therapeutic, chemo-preventive and chemo-sensitizing agent in diverse disease conditions. As the isolated pure form has poor solubility and pharmacokinetic problems, therefore it is encapsulated in to several nano-formulations to improve its bioavailability. Here in the current study, we aim to compare different nano-formulations of curcumin for their chemo-sensitizing activity in doxorubicin (DOX) resistant K562 cells. Four different curcumin formulations were prepared namely DMSO assisted curcumin nano-dispersion (CurD, 260 nm), liposomal curcumin (CurL, 165 nm), MPEG-PCL micellar curcumin (CurM, 18 nm) and cyclodextrin encapsulated curcumin (CurN, 37 nm). The formulations were subjected to particle characterizations (size, zeta potential, release studies), followed by biological assays such as cellular uptake, P-gp inhibitory activity and reversal of DOX resistance by co-treatment with DOX. Curcumin uptake in K562N and K562R cells was mildly reduced when treated with CurL and CurM, while for CurD and CurN the uptake remained equivalent. However, CurL retained P-gp inhibitory activity of curcumin and with a considerable chemo-sensitizing effect but CurM showed no P-gp inhibitory activity. CurN retained above biological activities, but requires a secondary carrier under in vivo conditions. From the results, CurM was found to be most suitable for solubilization of curcumin where as CurL can be considered as most suitable nano-formulation for reversal of DOX resistance.

  13. Knockdown of long non-coding RNA Taurine Up-Regulated 1 inhibited doxorubicin resistance of bladder urothelial carcinoma via Wnt/β-catenin pathway.

    Science.gov (United States)

    Xie, Dalong; Zhang, Hui; Hu, Xuanhao; Shang, Chao

    2017-10-24

    In genitourinary system, bladder cancer (BC) is the most common and lethal malignant tumor, which most common type is bladder urothelial carcinoma (BUC). Long non-coding RNA (lncRNA) Taurine Up-Regulated 1 (TUG1) gene is high-expressed in several malignant tumors, including BC. In this study, over-expression of TUG1 was found in BUC tissues and cell line resistant to doxorubicin (Dox). Knockdown of TUG1 inhibited the Dox resistance and promoted the cytotoxicity induced by Dox in T24/Dox cells. TUG1 knockdown also depressed the Wnt/β-catenin pathway, and the activation the Wnt/β-catenin pathway partly reversed the inhibitory effects of TUG1 knockdown on Dox resistance in T24/Dox cells. In conclusion, up-regulation of lncRNA TUG1 was related with the poor response of BUC patients to Dox chemotherapy, knockdown of TUG1 inhibited the Dox resistance of BUC cells via Wnt/β-catenin pathway. These findings might assist in the discovery of novel potential diagnostic and therapeutic target for BUC, thereby improve the effects of clinical treatment in patients.

  14. The stress granule protein Vgl1 and poly(A)-binding protein Pab1 are required for doxorubicin resistance in the fission yeast Schizosaccharomyces pombe

    Energy Technology Data Exchange (ETDEWEB)

    Morita, Takahiro [Laboratory of Molecular Pharmacogenomics, School of Pharmaceutical Sciences, Kinki University, Kowakae 3-4-1, Higashi-Osaka 577-8502 (Japan); Satoh, Ryosuke [Laboratory of Molecular Pharmacogenomics, School of Pharmaceutical Sciences, Kinki University, Kowakae 3-4-1, Higashi-Osaka 577-8502 (Japan); Japan Society for the Promotion of Science, 1-8 Chiyoda-ku, Tokyo 102-8472 (Japan); Umeda, Nanae; Kita, Ayako [Laboratory of Molecular Pharmacogenomics, School of Pharmaceutical Sciences, Kinki University, Kowakae 3-4-1, Higashi-Osaka 577-8502 (Japan); Sugiura, Reiko, E-mail: sugiurar@phar.kindai.ac.jp [Laboratory of Molecular Pharmacogenomics, School of Pharmaceutical Sciences, Kinki University, Kowakae 3-4-1, Higashi-Osaka 577-8502 (Japan)

    2012-01-06

    Highlights: Black-Right-Pointing-Pointer Stress granules (SGs) as a mechanism of doxorubicin tolerance. Black-Right-Pointing-Pointer We characterize the role of stress granules in doxorubicin tolerance. Black-Right-Pointing-Pointer Deletion of components of SGs enhances doxorubicin sensitivity in fission yeast. Black-Right-Pointing-Pointer Doxorubicin promotes SG formation when combined with heat shock. Black-Right-Pointing-Pointer Doxorubicin regulates stress granule assembly independent of eIF2{alpha} phosphorylation. -- Abstract: Doxorubicin is an anthracycline antibiotic widely used for chemotherapy. Although doxorubicin is effective in the treatment of several cancers, including solid tumors and leukemias, the basis of its mechanism of action is not completely understood. Here, we describe the effects of doxorubicin and its relationship with stress granules formation in the fission yeast, Schizosaccharomyces pombe. We show that disruption of genes encoding the components of stress granules, including vgl1{sup +}, which encodes a multi-KH type RNA-binding protein, and pab1{sup +}, which encodes a poly(A)-binding protein, resulted in greater sensitivity to doxorubicin than seen in wild-type cells. Disruption of the vgl1{sup +} and pab1{sup +} genes did not confer sensitivity to other anti-cancer drugs such as cisplatin, 5-fluorouracil, and paclitaxel. We also showed that doxorubicin treatment promoted stress granule formation when combined with heat shock. Notably, doxorubicin treatment did not induce hyperphosphorylation of eIF2{alpha}, suggesting that doxorubicin is involved in stress granule assembly independent of eIF2{alpha} phosphorylation. Our results demonstrate the usefulness of fission yeast for elucidating the molecular targets of doxorubicin toxicity and suggest a novel drug-resistance mechanism involving stress granule assembly.

  15. The stress granule protein Vgl1 and poly(A)-binding protein Pab1 are required for doxorubicin resistance in the fission yeast Schizosaccharomyces pombe

    International Nuclear Information System (INIS)

    Morita, Takahiro; Satoh, Ryosuke; Umeda, Nanae; Kita, Ayako; Sugiura, Reiko

    2012-01-01

    Highlights: ► Stress granules (SGs) as a mechanism of doxorubicin tolerance. ► We characterize the role of stress granules in doxorubicin tolerance. ► Deletion of components of SGs enhances doxorubicin sensitivity in fission yeast. ► Doxorubicin promotes SG formation when combined with heat shock. ► Doxorubicin regulates stress granule assembly independent of eIF2α phosphorylation. -- Abstract: Doxorubicin is an anthracycline antibiotic widely used for chemotherapy. Although doxorubicin is effective in the treatment of several cancers, including solid tumors and leukemias, the basis of its mechanism of action is not completely understood. Here, we describe the effects of doxorubicin and its relationship with stress granules formation in the fission yeast, Schizosaccharomyces pombe. We show that disruption of genes encoding the components of stress granules, including vgl1 + , which encodes a multi-KH type RNA-binding protein, and pab1 + , which encodes a poly(A)-binding protein, resulted in greater sensitivity to doxorubicin than seen in wild-type cells. Disruption of the vgl1 + and pab1 + genes did not confer sensitivity to other anti-cancer drugs such as cisplatin, 5-fluorouracil, and paclitaxel. We also showed that doxorubicin treatment promoted stress granule formation when combined with heat shock. Notably, doxorubicin treatment did not induce hyperphosphorylation of eIF2α, suggesting that doxorubicin is involved in stress granule assembly independent of eIF2α phosphorylation. Our results demonstrate the usefulness of fission yeast for elucidating the molecular targets of doxorubicin toxicity and suggest a novel drug-resistance mechanism involving stress granule assembly.

  16. ANTIPSYCHOTICS REVERSE P-GLYCOPROTEIN-MEDIATED DOXORUBICIN RESISTANCE IN HUMAN UTERINE SARCOMA MES-SA/Dx5 CELLS: A NOVEL APPROACH TO CANCER CHEMOTHERAPY.

    Science.gov (United States)

    Angelini, A; Ciofani, G; Conti, P

    2015-01-01

    Multidrug resistance (MDR) mediated by P-glycoprotein (Pgp) remains one of the major obstacles to effective cancer chemotherapy. Several chemosensitizers have been used in vivo and in vitro to reverse MDR but have exhibited several unwanted side effects. Antipsychotics are often administered to treat psychiatric disorders such as delirium, anxiety and sleep disorders in cancer patients during chemotherapy. The present in vitro study, examined the effects of two common antipsychotic compounds, haloperidol and risperidone, and a natural compound such as theobromine on reversing MDR Pgp-mediated, to evaluate their potential use as chemosensitizing agents. The human doxorubicin (doxo) resistant uterine sarcoma cells (MES-SA/Dx5) that overexpress Pgp (100-fold), were treated with the antipsychotic alone (1, 10 and 20 μM) or in combination with different concentrations of doxo (2, 4 and 8 μM). The accumulation and cytotoxicity of doxo (MTT assay) and cellular GSH content (GSH assay) in comparison with verapamil, a well-known Pgp inhibitor, used as reference molecule were examined. It was found that the three compounds significantly enhanced the intracellular accumulation of doxo in resistant cancer cells, when compared with cells receiving doxo alone (p 30%) in resistant cells, when compared to untreated control cells (ptheobromine showed to be an effective Pgp inhibitor with the lowest toxicity.

  17. Synthesis of poly[N-(2-hydroxypropyl)methacrylamide] conjugates of inhibitors of the ABC transporter that overcome multidrug resistance in doxorubicin-resistant P388 cells in vitro

    Czech Academy of Sciences Publication Activity Database

    Šubr, Vladimír; Sivák, Ladislav; Koziolová, Eva; Braunová, Alena; Pechar, Michal; Strohalm, Jiří; Kabešová, Martina; Říhová, Blanka; Ulbrich, Karel; Kovář, Marek

    2014-01-01

    Roč. 15, č. 8 (2014), s. 3030-3043 ISSN 1525-7797 R&D Projects: GA ČR GAP301/12/1254; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61389013 ; RVO:61388971 Keywords : N-(2-hydroxypropyl)methacrylamide copolymers * multidrug resistance * P-glycoprotein inhibitors Subject RIV: CD - Macromolecular Chemistry; FD - Oncology ; Hematology (MBU-M) Impact factor: 5.750, year: 2014

  18. HIF-1 activation induces doxorubicin resistance in MCF7 3-D spheroids via P-glycoprotein expression: a potential model of the chemo-resistance of invasive micropapillary carcinoma of the breast

    Directory of Open Access Journals (Sweden)

    Doublier Sophie

    2012-01-01

    Full Text Available Abstract Background Invasive micropapillary carcinoma (IMPC of the breast is a distinct and aggressive variant of luminal type B breast cancer that does not respond to neoadjuvant chemotherapy. It is characterized by small pseudopapillary clusters of cancer cells with inverted cell polarity. To investigate whether hypoxia-inducible factor-1 (HIF-1 activation may be related to the drug resistance described in this tumor, we used MCF7 cancer cells cultured as 3-D spheroids, which morphologically simulate IMPC cell clusters. Methods HIF-1 activation was measured by EMSA and ELISA in MCF7 3-D spheroids and MCF7 monolayers. Binding of HIF-1α to MDR-1 gene promoter and modulation of P-glycoprotein (Pgp expression was evaluated by ChIP assay and FACS analysis, respectively. Intracellular doxorubicin retention was measured by spectrofluorimetric assay and drug cytotoxicity by annexin V-FITC measurement and caspase activity assay. Results In MCF7 3-D spheroids HIF-1 was activated and recruited to participate to the transcriptional activity of MDR-1 gene, coding for Pgp. In addition, Pgp expression on the surface of cells obtained from 3-D spheroids was increased. MCF7 3-D spheroids accumulate less doxorubicin and are less sensitive to its cytotoxic effects than MCF7 cells cultured as monolayer. Finally, HIF-1α inhibition either by incubating cells with 3-(5'-hydroxymethyl-2'-furyl-1-benzylindazole (a widely used HIF-1α inhibitor or by transfecting cells with specific siRNA for HIF-1α significantly decreased the expression of Pgp on the surface of cells and increased the intracellular doxorubicin accumulation in MCF7 3-D spheroids. Conclusions MCF7 breast cancer cells cultured as 3-D spheroids are resistant to doxorubicin and this resistance is associated with an increased Pgp expression in the plasma membrane via activation of HIF-1. The same mechanism may be suggested for IMPC drug resistance.

  19. Effective molecular targeting of CDK4/6 and IGF-1R in a rare FUS-ERG fusion CDKN2A-deletion doxorubicin-resistant Ewing's sarcoma patient-derived orthotopic xenograft (PDOX) nude-mouse model.

    Science.gov (United States)

    Murakami, Takashi; Singh, Arun S; Kiyuna, Tasuku; Dry, Sarah M; Li, Yunfeng; James, Aaron W; Igarashi, Kentaro; Kawaguchi, Kei; DeLong, Jonathan C; Zhang, Yong; Hiroshima, Yukihiko; Russell, Tara; Eckardt, Mark A; Yanagawa, Jane; Federman, Noah; Matsuyama, Ryusei; Chishima, Takashi; Tanaka, Kuniya; Bouvet, Michael; Endo, Itaru; Eilber, Fritz C; Hoffman, Robert M

    2016-07-26

    Ewing's sarcoma is a rare and aggressive malignancy. In the present study, tumor from a patient with a Ewing's sarcoma with cyclin-dependent kinase inhibitor 2A/B (CDKN2A/B) loss and FUS-ERG fusion was implanted in the right chest wall of nude mice to establish a patient-derived orthotopic xenograft (PDOX) model. The aim of the present study was to determine efficacy of cyclin-dependent kinase 4/6 (CDK4/6) and insulin-like growth factor-1 receptor (IGF-1R) inhibitors on the Ewing's sarcoma PDOX. The PDOX models were randomized into the following groups when tumor volume reached 50 mm3: G1, untreated control; G2, doxorubicin (DOX) (intraperitoneal (i.p.) injection, weekly, for 2 weeks); G3, CDK4/6 inhibitor (palbociclib, PD0332991, per oral (p.o.), daily, for 14 days); G4, IGF-1R inhibitor (linsitinib, OSI-906, p.o., daily, for 14 days). Tumor growth was significantly suppressed both in G3 (palbociclib) and in G4 (linsitinib) compared to G1 (untreated control) at all measured time points. In contrast, DOX did not inhibit tumor growth at any time point, which is consistent with the failure of DOX to control tumor growth in the patient. The results of the present study demonstrate the power of the PDOX model to identify effective targeted molecular therapy of a recalcitrant DOX-resistant Ewing's sarcoma with specific genetic alterations. The results of this study suggest the potential of PDOX models for individually-tailored, effective targeted therapy for recalcitrant cancer.

  20. Eribulin regresses a doxorubicin-resistant Ewing's sarcoma with a FUS-ERG fusion and CDKN2A-deletion in a patient-derived orthotopic xenograft (PDOX) nude mouse model.

    Science.gov (United States)

    Miyake, Kentaro; Murakami, Takashi; Kiyuna, Tasuku; Igarashi, Kentaro; Kawaguchi, Kei; Li, Yunfeng; Singh, Arun S; Dry, Sarah M; Eckardt, Mark A; Hiroshima, Yukihiko; Momiyama, Masashi; Matsuyama, Ryusei; Chishima, Takashi; Endo, Itaru; Eilber, Fritz C; Hoffman, Robert M

    2018-01-01

    Ewing's sarcoma is a recalcitrant tumor greatly in need of more effective therapy. The aim of this study was to determine the efficacy of eribulin on a doxorubicin (DOX)-resistant Ewing's sarcoma patient derived orthotopic xenograft (PDOX) model. The Ewing's sarcoma PDOX model was previously established in the right chest wall of nude mice from tumor resected form the patient's right chest wall. In the previous study, the Ewing's sarcoma PDOX was resistant to doxorubicin (DOX) and sensitive to palbociclib and linsitinib. In the present study, the PDOX models were randomized into three groups when the tumor volume reached 60 mm 3 : G1, untreated control (n = 6); G2, DOX treated (n = 6), intraperitoneal (i.p.) injection, weekly, for 2 weeks); G3, Eribulin treated (n = 6, intravenous (i.v.) injection, weekly for 2 weeks). All mice were sacrificed on day 15. Changes in body weight and tumor volume were assessed two times per week. Tumor weight was measured after sacrifice. DOX did not suppress tumor growth compared to the control group (P = 0.589), consistent with the previous results in the patient and PDOX. Eribulin regressed tumor size significantly compared to G1 and G2 (P = 0.006, P = 0.017) respectively. No significant difference was observed in body weight among any group. Our results demonstrate that eribulin is a promising novel therapeutic agent for Ewing's sarcoma. © 2017 Wiley Periodicals, Inc.

  1. Effects of human pharmaceuticals on cytotoxicity, EROD activity and ROS production in fish hepatocytes

    International Nuclear Information System (INIS)

    Laville, N.; Aiet-Aiessa, S.; Gomez, E.; Casellas, C.; Porcher, J.M.

    2004-01-01

    Pharmaceuticals are found in the aquatic environment but their potential effects on non-target species like fish remain unknown. This in vitro study is a first approach in the toxicity assessment of human drugs on fish. Nine pharmaceuticals were tested on two fish hepatocyte models: primary cultures of rainbow trout hepatocytes (PRTH) and PLHC-1 fish cell line. Cell viability, interaction with cytochrome P450 1A (CYP1A) enzyme and oxidative stress were assessed by using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrasodium bromide tetrazolium (MTT), 7-ethoxyresorufin-o-deethylase (EROD) and dichlorofluorescein (DCFH-DA) assays, respectively. The tested drugs were clofibrate (CF), fenofibrate (FF), carbamazepine (CBZ), fluoxetine (FX), diclofenac (DiCF), propranolol (POH), sulfamethoxazole (SFX), amoxicillin (AMX) and gadolinium chloride (GdCl 3 ). All substances were cytotoxic, except AMX at concentration up to 500 μM. The calculated MTT EC 50 values ranged from 2 μM (CF) to 651 μM (CBZ) in PLHC-1, and from 53 μM (FF) to 962 μM (GdCl 3 ) in PRTH. CF, FF, and FX were the most cytotoxic drugs and induced oxidative stress before being cytotoxic. Compared to hepatocytes from human and dog, fish hepatocytes seemed to be more susceptible to the peroxisome proliferators (PPs) CF and FF. In PLHC-1 cells none of the tested drugs induced the EROD activity whereas POH appeared as a weak EROD inducer in PRTH. Moreover, in PRTH, SFX, DiCF, CBZ and to a lesser extend, FF and CF inhibited the basal EROD activity at clearly sublethal concentrations which may be of concern at the biological and chemical levels in a multipollution context

  2. Quantitative Proteomics Analysis Identifies Mitochondria as Therapeutic Targets of Multidrug-Resistance in Ovarian Cancer

    Science.gov (United States)

    Chen, Xiulan; Wei, Shasha; Ma, Ying; Lu, Jie; Niu, Gang; Xue, Yanhong; Chen, Xiaoyuan; Yang, Fuquan

    2014-01-01

    Doxorubicin is a widely used chemotherapeutic agent for the treatment of a variety of solid tumors. However, resistance to this anticancer drug is a major obstacle to the effective treatment of tumors. As mitochondria play important roles in cell life and death, we anticipate that mitochondria may be related to drug resistance. Here, stable isotope labeling by amino acids in cell culture (SILAC)-based quantitative proteomic strategy was applied to compare mitochondrial protein expression in doxorubicin sensitive OVCAR8 cells and its doxorubicin-resistant variant NCI_ADR/RES cells. A total of 2085 proteins were quantified, of which 122 proteins displayed significant changes in the NCI_ADR/RES cells. These proteins participated in a variety of cell processes including cell apoptosis, substance metabolism, transport, detoxification and drug metabolism. Then qRT-PCR and western blot were applied to validate the differentially expressed proteins quantified by SILAC. Further functional studies with RNAi demonstrated TOP1MT, a mitochondrial protein participated in DNA repair, was involved in doxorubicin resistance in NCI_ADR/RES cells. Besides the proteomic study, electron microscopy and fluorescence analysis also observed that mitochondrial morphology and localization were greatly altered in NCI_ADR/RES cells. Mitochondrial membrane potential was also decreased in NCI_ADR/RES cells. All these results indicate that mitochondrial function is impaired in doxorubicin-resistant cells and mitochondria play an important role in doxorubicin resistance. This research provides some new information about doxorubicin resistance, indicating that mitochondria could be therapeutic targets of doxorubicin resistance in ovarian cancer cells. PMID:25285166

  3. Fish cell lines as a tool for the ecotoxicity assessment and ranking of engineered nanomaterials.

    Science.gov (United States)

    Bermejo-Nogales, A; Fernández-Cruz, M L; Navas, J M

    2017-11-01

    Risk assessment of engineered nanomaterials (ENMs) is being hindered by the sheer production volume of these materials. In this regard, the grouping and ranking of ENMs appears as a promising strategy. Here we sought to evaluate the usefulness of in vitro systems based on fish cell lines for ranking a set of ENMs on the basis of their cytotoxicity. We used the topminnow (Poeciliopsis lucida) liver cell line (PLHC-1) and the rainbow trout (Oncorhynchus mykiss) fibroblast-like gonadal cell line (RTG-2). ENMs were obtained from the EU Joint Research Centre repository. The size frequency distribution of ENM suspensions in cell culture media was characterized. Cytotoxicity was evaluated after 24 h of exposure. PLHC-1 cells exhibited higher sensitivity to the ENMs than RTG-2 cells. ZnO-NM was found to exert toxicity mainly by altering lysosome function and metabolic activity, while multi-walled carbon nanotubes (MWCNTs) caused plasma membrane disruption at high concentrations. The hazard ranking for toxicity (ZnO-NM > MWCNT ≥ CeO 2 -NM = SiO 2 -NM) was inversely related to the ranking in size detected in culture medium. Our findings reveal the suitability of fish cell lines for establishing hazard rankings of ENMs in the framework of integrated approaches to testing and assessment. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Proteomic Differences in Feline Fibrosarcomas Grown Using Doxorubicin-Sensitive and -Resistant Cell Lines in the Chick Embryo Model

    Directory of Open Access Journals (Sweden)

    Katarzyna Zabielska-Koczywąs

    2018-02-01

    Full Text Available Proteomic analyses are rapid and powerful tools that are used to increase the understanding of cancer pathogenesis, discover cancer biomarkers and predictive markers, and select and monitor novel targets for cancer therapy. Feline injection-site sarcomas (FISS are aggressive skin tumours with high recurrence rates, despite treatment with surgery, radiotherapy, and chemotherapy. Doxorubicin is a drug of choice for soft tissue sarcomas, including FISS. However, multidrug resistance is one of the major causes of chemotherapy failure. The main aim of the present study was to identify proteins that differentiate doxorubicin-resistant from doxorubicin-sensitive FISS using two-dimensional gel electrophoresis (2DE, followed by matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF MS analysis. Using the three-dimensional (3D preclinical in ovo model, which resembles features of spontaneous fibrosarcomas, three significantly (p ≤ 0.05 differentially expressed proteins were identified in tumours grown from doxorubicin-resistant fibrosarcoma cell lines (FFS1 and FFS3 in comparison to the doxorubicin-sensitive one (FFS5: Annexin A5 (ANXA5, Annexin A3 (ANXA3, and meiosis-specific nuclear structural protein 1 (MNS1. Moreover, nine other proteins were significantly differentially expressed in tumours grown from the high doxorubicin-resistant cell line (FFS1 in comparison to sensitive one (FFS5. This study may be the first proteomic fingerprinting of FISS reported, identifying potential candidates for specific predictive biomarkers and research targets for doxorubicin-resistant FISS.

  5. Monitoring of dioxin-like, estrogenic and anti-androgenic activities in sediments of the Bizerta lagoon (Tunisia) by means of in vitro cell-based bioassays: contribution of low concentrations of polynuclear aromatic hydrocarbons (PAHs).

    Science.gov (United States)

    Louiz, I; Kinani, S; Gouze, M-E; Ben-Attia, M; Menif, D; Bouchonnet, S; Porcher, J M; Ben-Hassine, O K; Aït-Aïssa, S

    2008-09-01

    We used an array of in vitro cell-based bioassays to assess dioxin-like, estrogenic and (anti-)androgenic activities in organic extracts of sediments from the Bizerta lagoon, one of the largest Tunisian lagoons subjected to various anthropogenic and industrial pressures. The sediments were sampled both in winter and summer 2006 in 6 stations differently impacted and in one reference station located in the seawards entrance of Ghar el Melh lagoon. Chemical analyses of the 16 priority PAHs showed that the sediments were low to moderately contaminated (2-537 ng/g dry weight). By using the estrogen- (MELN) and androgen-responsive (MDA-kb2) reporter cell lines, significant estrogenic and anti-androgenic activities were detected only in the Menzel Bourguiba (MB) site, the most contaminated site, both in winter and summer. By using 7-ethoxyresorufin-O-deethylase (EROD) induction in the fish PLHC-1 cell line after both 4 and 24 h of cell exposure, dioxin-like activities were detected in all analysed samples. Dioxin-like activities were higher after 4 h exposure, and varied according to the sites and the sampling season. While highly significant correlation was observed between bioassay- and chemical analyses-derived toxic equivalents (TEQs), PAHs accounted for only a small part (up to 4%) of the detected biological activities, suggesting that other readily metabolised EROD-inducing compounds were present. This study argues for the use of short time exposure to assess biological TEQs in low contaminated samples and provides new induction equivalent factors (IEF(4h)) for 16 PAHs in the PLHC-1 cell line. Finally, our results stress the need to further characterise the nature of organic chemical contamination as well as its long-term impacts on aquatic wildlife in the Bizerta lagoon.

  6. Mesenchymal change and drug resistance in neuroblastoma.

    Science.gov (United States)

    Naiditch, Jessica A; Jie, Chunfa; Lautz, Timothy B; Yu, Songtao; Clark, Sandra; Voronov, Dimitry; Chu, Fei; Madonna, Mary Beth

    2015-01-01

    Metastatic initiation has many phenotypic similarities to epithelial-to-mesenchymal transition, including loss of cell-cell adhesion, increased invasiveness, and increased cell mobility. We have previously demonstrated that drug resistance is associated with a metastatic phenotype in neuroblastoma (NB). The purpose of this project was to determine if the development of doxorubicin resistance is associated with characteristics of mesenchymal change in human NB cells. Total RNA was isolated from wild type (WT) and doxorubicin-resistant (DoxR) human NB cell lines (SK-N-SH and SK-N-BE(2)C) and analyzed using the Illumina Human HT-12 version 4 Expression BeadChip. Differentially expressed genes (DEGs) were identified. Volcano plots and heat maps were generated. Genes of interest with a fold change in expression >1.5 and an adjusted P change via multiple pathways in the transition to a drug-resistant state. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Regorafenib overcomes chemotherapeutic multidrug resistance mediated by ABCB1 transporter in colorectal cancer: In vitro and in vivo study.

    Science.gov (United States)

    Wang, Yi-Jun; Zhang, Yun-Kai; Zhang, Guan-Nan; Al Rihani, Sweilem B; Wei, Meng-Ning; Gupta, Pranav; Zhang, Xiao-Yu; Shukla, Suneet; Ambudkar, Suresh V; Kaddoumi, Amal; Shi, Zhi; Chen, Zhe-Sheng

    2017-06-28

    Chemotherapeutic multidrug resistance (MDR) is a significant challenge to overcome in clinic practice. Several mechanisms contribute to MDR, one of which is the augmented drug efflux induced by the upregulation of ABCB1 in cancer cells. Regorafenib, a multikinase inhibitor targeting the RAS/RAF/MEK/ERK pathway, was approved by the FDA to treat metastatic colorectal cancer and gastrointestinal stromal tumors. We investigated whether and how regorafenib overcame MDR mediated by ABCB1. The results showed that regorafenib reversed the ABCB1-mediated MDR and increased the accumulation of [ 3 H]-paclitaxel in ABCB1-overexpressing cells by suppressing efflux activity of ABCB1, but not altering expression level and localization of ABCB1. Regorafenib inhibited ATPase activity of ABCB1. In mice bearing resistant colorectal tumors, regorafenib raised the intratumoral concentration of paclitaxel and suppressed the growth of resistant colorectal tumors. But regorafenib did not induce cardiotoxicity/myelosuppression of paclitaxel in mice. Strategy to reposition one FDA-approved anticancer drug regorafenib to overcome the resistance of another FDA-approved, widely used chemotherapeutic paclitaxel, may be a promising direction for the field of adjuvant chemotherapy. This study provides clinical rationale for combination of conventional chemotherapy and targeted anticancer agents. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Oxygen radical detoxification enzymes in doxorubicin-sensitive and -resistant P388 murine leukemia cells

    International Nuclear Information System (INIS)

    Ramu, A.; Cohen, L.; Glaubiger, D.

    1984-01-01

    One of the proposed mechanisms for the cytotoxic effects of anthracycline compounds suggests that the effect is mediated through the formation of intracellular superoxide radicals. It is therefore possible that doxorubicin resistance is associated with increased intracellular enzyme capacity to convert these superoxide radicals to inactive metabolites. We have measured the relative activities of superoxide dismutase, glutathione peroxidase, and catalase in P388 mouse leukemia cells and in a doxorubicin-resistant subline. Since oxygen-reactive metabolites also play a role in mediating the cytotoxicity of ionizing radiation, the radiosensitivity of both cell lines was also studied. No significant differences in superoxide dismutase activity between these cell lines was observed, indicating that they have a similar capacity to convert superoxide anion radicals to hydrogen peroxide. P388 cells that are resistant to doxorubicin have 1.5 times the glutathione content and 1.5 times the activity of glutathione peroxidase measured in drug-sensitive P388 cells. However, incubation with 1-chloro-2,4-dinitrobenzene, which covalently binds glutathione, had no effect on the sensitivity of either cell line to doxorubicin. Measured catalase activity in drug-resistant P388 cells was one-third of the activity measured in doxorubicin-sensitive P388 cells. The activity of this enzyme was much higher than that of glutathione peroxidase in terms of H 2 O 2 deactivation in both cell lines. It is therefore unlikely that doxorubicin-resistant P388 cells have an increased ability to detoxify reactive oxygen metabolites when compared to drug-sensitive cells. Doxorubicin-resistant P388 cells were significantly more sensitive to X-irradiation than were drug-sensitive P388 cells. These observations suggest that the difference in catalase activity in these cell lines may be associated with the observed differences in radiosensitivity

  9. Cellular robustness conferred by genetic crosstalk underlies resistance against chemotherapeutic drug doxorubicin in fission yeast.

    Directory of Open Access Journals (Sweden)

    Zoey Tay

    Full Text Available Doxorubicin is an anthracycline antibiotic that is among one of the most commonly used chemotherapeutic agents in the clinical setting. The usage of doxorubicin is faced with many problems including severe side effects and chemoresistance. To overcome these challenges, it is important to gain an understanding of the underlying molecular mechanisms with regards to the mode of action of doxorubicin. To facilitate this aim, we identified the genes that are required for doxorubicin resistance in the fission yeast Schizosaccharomyces pombe. We further demonstrated interplay between factors controlling various aspects of chromosome metabolism, mitochondrial respiration and membrane transport. In the nucleus we observed that the subunits of the Ino80, RSC, and SAGA complexes function in the similar epistatic group that shares significant overlap with the homologous recombination genes. However, these factors generally act in synergistic manner with the chromosome segregation regulator DASH complex proteins, possibly forming two major arms for regulating doxorubicin resistance in the nucleus. Simultaneous disruption of genes function in membrane efflux transport or the mitochondrial respiratory chain integrity in the mutants defective in either Ino80 or HR function resulted in cumulative upregulation of drug-specific growth defects, suggesting a rewiring of pathways that synergize only when the cells is exposed to the cytotoxic stress. Taken together, our work not only identified factors that are required for survival of the cells in the presence of doxorubicin but has further demonstrated that an extensive molecular crosstalk exists between these factors to robustly confer doxorubicin resistance.

  10. Assessment of the disinfection capacity and eco-toxicological impact of atmospheric cold plasma for treatment of food industry effluents.

    Science.gov (United States)

    Patange, Apurva; Boehm, Daniela; Giltrap, Michelle; Lu, Peng; Cullen, P J; Bourke, Paula

    2018-08-01

    Generation of wastewater is one of the main environmental sustainability issues across food sector industries. The constituents of food process effluents are often complex and require high energy and processing for regulatory compliance. Wastewater streams are the subject of microbiological and chemical criteria, and can have a significant eco-toxicological impact on the aquatic life. Thus, innovative treatment approaches are required to mitigate environmental impact in an energy efficient manner. Here, dielectric barrier discharge atmospheric cold plasma (ACP) was evaluated for control of key microbial indicators encountered in food industry effluent. This study also investigated the eco-toxicological impact of cold plasma treatment of the effluents using a range of aquatic bioassays. Continuous ACP treatment was applied to synthetic dairy and meat effluents. Microbial inactivation showed treatment time dependence with significant reduction in microbial populations within 120 s, and to undetectable levels after 300 s. Post treatment retention time emerged as critical control parameter which promoted ACP bacterial inactivation efficiency. Moreover, ACP treatment for 20 min achieved significant reduction (≥2 Log 10 ) in Bacillus megaterium endospores in wastewater effluent. Acute aquatic toxicity was assessed using two fish cell lines (PLHC-1 and RTG-2) and a crustacean model (Daphnia magna). Untreated effluents were toxic to the aquatic models, however, plasma treatment limited the toxic effects. Differing sensitivities were observed to ACP treated effluents across the different test bio-assays in the following order: PLHC-1 > RTG-2 ≥ D. magna; with greater sensitivity retained to plasma treated meat effluent than dairy effluent. The toxic effects were dependent on concentration and treatment time of the ACP treated effluent; with 30% cytotoxicity in D. magna and fish cells observed after 24 h of exposure to ACP treated effluent for

  11. The naphthoquinones, vitamin K3 and its structural analog plumbagin, are substrates of the multidrug resistance-linked ABC drug transporter ABCG2

    Science.gov (United States)

    Shukla, Suneet; Wu, Chung-Pu; Nandigama, Krishnamachary; Ambudkar, Suresh V.

    2008-01-01

    Vitamin K3 (Menadione; 2-methyl-1,4-naphthoquinone) is a structural precursor of vitamins K1 and K2 which are essential for blood clotting. The naturally occurring structural analog of this vitamin, plumbagin (5-hydroxy-menadione), is known to modulate cellular proliferation, apoptosis, carcinogenesis, and radioresistance. We, here, report that both vitamin K3 and plumbagin are substrates of the multidrug resistance-linked ATP binding cassette (ABC) drug transporter, ABCG2. Vitamin K3 and plumbagin specifically inhibited the ABCG2-mediated efflux of mitoxantrone, but did not have any effect on the ABCB1-mediated efflux of rhodamine 123. This inhibition of ABCG2 function was due to their interaction at the substrate-binding site(s). They inhibited the binding of [125I]-Iodoarylazidoprazosin (IAAP), a substrate of ABCG2, to this transporter in a concentration-dependent manner with IC50 values of 7.3 and 22.6 μM, respectively, but had no effect on the binding of this photoaffinity analog to ABCB1. Both compounds stimulated ABCG2-mediated ATP hydrolysis and also inhibited the mitoxantrone-stimulated ATPase activity of this transporter, but did not have any significant effect on the ATPase activity of ABCB1. In a cytotoxicity assay, ABCG2-expressing HEK cells were 2.8- and 2.3-fold resistant to plumbagin and vitamin K3, respectively, compared to the control cells, suggesting that they are substrates of this transporter. Collectively, these data demonstrate for the first time that vitamin K3 is a substrate of the ABCG2 transporter. Thus, ABCG2 may have a role in the regulation of vitamin K3 levels in the body. In addition, vitamin K3 and its structural derivative, plumbagin, could potentially be used to modulate ABCG2 function. PMID:18065489

  12. The naphthoquinones, vitamin K3 and its structural analogue plumbagin, are substrates of the multidrug resistance linked ATP binding cassette drug transporter ABCG2.

    Science.gov (United States)

    Shukla, Suneet; Wu, Chung-Pu; Nandigama, Krishnamachary; Ambudkar, Suresh V

    2007-12-01

    Vitamin K3 (menadione; 2-methyl-1,4-naphthoquinone) is a structural precursor of vitamins K1 and K2, which are essential for blood clotting. The naturally occurring structural analogue of this vitamin, plumbagin (5-hydroxy-menadione), is known to modulate cellular proliferation, apoptosis, carcinogenesis, and radioresistance. We here report that both vitamin K3 and plumbagin are substrates of the multidrug resistance-linked ATP binding cassette drug transporter, ABCG2. Vitamin K3 and plumbagin specifically inhibited the ABCG2-mediated efflux of mitoxantrone but did not have any effect on the ABCB1-mediated efflux of rhodamine 123. This inhibition of ABCG2 function was due to their interaction at the substrate-binding site(s). Vitamin K3 and plumbagin inhibited the binding of [(125)I]iodoarylazidoprazosin, a substrate of ABCG2, to this transporter in a concentration-dependent manner with IC(50) values of 7.3 and 22.6 micromol/L, respectively, but had no effect on the binding of the photoaffinity analogue to ABCB1. Both compounds stimulated ABCG2-mediated ATP hydrolysis and also inhibited the mitoxantrone-stimulated ATPase activity of the ABCG2 transporter, but did not have any significant effect on the ATPase activity of ABCB1. In a cytotoxicity assay, ABCG2-expressing HEK cells were 2.8- and 2.3-fold resistant to plumbagin and vitamin K3, respectively, compared with the control cells, suggesting that they are substrates of this transporter. Collectively, these data show for the first time that vitamin K3 is a substrate of the ABCG2 transporter. Thus, ABCG2 may have a role in the regulation of vitamin K3 levels in the body. In addition, vitamin K3 and its structural derivative, plumbagin, could potentially be used to modulate ABCG2 function.

  13. Differential effects of the enantiomers of tamsulosin and tolterodine on P-glycoprotein and cytochrome P450 3A4.

    Science.gov (United States)

    Doricakova, Aneta; Theile, Dirk; Weiss, Johanna; Vrzal, Radim

    2017-01-01

    The pregnane X receptor (PXR) is a transcription factor regulating P-glycoprotein (P-gp; ABCB1)-mediated transport and cytochrome P450 3A4 (CYP3A4)-mediated metabolism of xenobiotics thereby affecting the pharmacokinetics of many drugs and potentially modulating clinical efficacy. Thus, pharmacokinetic drug-drug interactions can arise from PXR activation. Here, we examined whether the selective α1-adrenoreceptor blocker tamsulosin or the antagonist of muscarinic receptors tolterodine affect PXR-mediated regulation of CYP3A4 and of P-gp at the messenger RNA (mRNA) and protein level in an enantiomer-specific way. In addition, the effect of tamsulosin and tolterodine on P-gp activity was evaluated. We used quantitative real-time PCR, gene reporter assay, western blotting, rhodamine efflux assay, and calcein assay for determination of expression, activity, and inhibition of P-glycoprotein. The studied compounds significantly and concentration-dependently increased PXR activity in the ABCB1-driven luciferase-based reporter gene assay. We observed much stronger induction of ABCB1 mRNA by S-tamsulosin as compared to the R or racemic form. R or racemic form of tolterodine and R-tamsulosin concentration-dependently increased P-gp protein expression; the latter also enhanced P-gp efflux function in a rhodamine-based efflux assay. R-tamsulosin and all forms of tolderodine slightly inhibited P-gp. The effect on CYP3A4 expression followed the same pattern but was much weaker. Taken together, tamsulosin and tolterodine are demonstrated to interfere with P-gp and CYP3A4 regulation in an enantiomer-specific way.

  14. Neratinib reverses ATP-binding cassette B1-mediated chemotherapeutic drug resistance in vitro, in vivo, and ex vivo.

    Science.gov (United States)

    Zhao, Xiao-qin; Xie, Jing-dun; Chen, Xing-gui; Sim, Hong May; Zhang, Xu; Liang, Yong-ju; Singh, Satyakam; Talele, Tanaji T; Sun, Yueli; Ambudkar, Suresh V; Chen, Zhe-Sheng; Fu, Li-wu

    2012-07-01

    Neratinib, an irreversible inhibitor of epidermal growth factor receptor and human epidermal receptor 2, is in phase III clinical trials for patients with human epidermal receptor 2-positive, locally advanced or metastatic breast cancer. The objective of this study was to explore the ability of neratinib to reverse tumor multidrug resistance attributable to overexpression of ATP-binding cassette (ABC) transporters. Our results showed that neratinib remarkably enhanced the sensitivity of ABCB1-overexpressing cells to ABCB1 substrates. It is noteworthy that neratinib augmented the effect of chemotherapeutic agents in inhibiting the growth of ABCB1-overexpressing primary leukemia blasts and KBv200 cell xenografts in nude mice. Furthermore, neratinib increased doxorubicin accumulation in ABCB1-overexpressing cell lines and Rhodamine 123 accumulation in ABCB1-overexpressing cell lines and primary leukemia blasts. Neratinib stimulated the ATPase activity of ABCB1 at low concentrations but inhibited it at high concentrations. Likewise, neratinib inhibited the photolabeling of ABCB1 with [(125)I]iodoarylazidoprazosin in a concentration-dependent manner (IC(50) = 0.24 μM). Neither the expression of ABCB1 at the mRNA and protein levels nor the phosphorylation of Akt was affected by neratinib at reversal concentrations. Docking simulation results were consistent with the binding conformation of neratinib within the large cavity of the transmembrane region of ABCB1, which provides computational support for the cross-reactivity of tyrosine kinase inhibitors with human ABCB1. In conclusion, neratinib can reverse ABCB1-mediated multidrug resistance in vitro, ex vivo, and in vivo by inhibiting its transport function.

  15. Evaluation of the Antitumor Activity by Ni Nanoparticles with Verbascoside

    Directory of Open Access Journals (Sweden)

    Mingyue Chen

    2013-01-01

    Full Text Available Verbascoside (VB has attracted a great deal of attention due to ITS pharmacological properties. In our study, we synthesized a multifunctional verbascoside coated Ni nanoparticles (VB-Ni. Transmission electron microscopy (TEM and high performance liquid chromatography (HPLC display the characteristics of VB-Ni nanoparticles. Compared with VB, VB-Ni has been proven to induce apoptosis and resist the growth of doxorubicin-resistant K562 cells in vitro and in vivo. Thus, VB-Ni nanoparticles can be thought of as an ideal mode of cancer treatment.

  16. Circumvention of acquired resistance to doxorubicin in K562 human leukemia cells by oxatomide.

    Science.gov (United States)

    Ishikawa, M; Fujita, R; Furusawa, S; Takayanagi, M; Sasaki, K; Satoh, S

    2001-10-01

    We studied the effect of oxatomide, an antiallergic drug, on the resistance of K562 cells to doxorubicin. Oxatomide synergistically potentiated the cytotoxicity of doxorubicin in doxorubicin-resistant K562 cells (K562/DXR) at a concentration of 1-10 microM, but had hardly any synergistic effect on the parental cell line (K562) at the same concentration. Oxatomide inhibit P-glycoprotein pump-efflux activity and the binding of [3H]-azidopine to the cell-surface protein P-glycoprotein, in a dose-related manner. These results indicate that oxatomide reverses the multidrug-resistance phenotype through direct interaction with P-glycoprotein.

  17. Characterization of quality of sediments from Paranaguá Bay (Brazil) by combined in vitro bioassays and chemical analyses.

    Science.gov (United States)

    Rizzi, Juliane; Pérez-Albaladejo, Elisabet; Fernandes, Denise; Contreras, Javier; Froehner, Sandro; Porte, Cinta

    2017-07-01

    The present study characterizes the quality of sediments from the Paranaguá Estuarine Complex (South Brazil). Polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) were determined in sediment samples together with a series of different in vitro bioassays. The fish hepatoma cell line (PLHC-1) was used to determine the presence of cytotoxic compounds and CYP1A- and oxidative stress-inducing agents in sediment extracts. Ovarian microsomal fractions from sea bass (Dicentrarchus labrax) were used to detect the presence of endocrine disrupters that interfered with the synthesis of estrogens (ovarian CYP19). Despite the relatively low levels of pollutants and no evidence of negative effects based on guideline levels, sediments collected close to harbors were enriched with CYP1A-inducing agents and they showed higher cytotoxicity. In contrast, sediments from internal areas inhibited CYP19 activity, which suggests the presence of endocrine disrupters at these sites. Overall, the selected bioassays and the chemistry data led to the identification of potentially impacted areas along the Paranaguá Estuarine Complex that would require further action to improve their environmental quality. Environ Toxicol Chem 2017;36:1811-1819. © 2016 SETAC. © 2016 SETAC.

  18. Bioassessment of bioremediation products in aquatic systems using cytotoxic and in vitro immune function assays

    International Nuclear Information System (INIS)

    Rice, C.D.; Roszell, L.E.

    1995-01-01

    Estuarine sediments and overlying water were collected from Back Bay Mississippi and placed in five 7.5 x 61 cm. glass-column mesocosms with a peristaltic recirculating system. Four columns received a sample of artificially weathered Louisiana Crude Oil spiked with either N + P, a PAH-metabolizing bacterial consortium collected in situ, or both. A fifth column excluded oil, bacteria, and nutrients. Aliphatic and aromatic fractions were extracted from each system and diluted in iso-octane. Poecoliopsis Hepatoma Cells (PLHC-1) and Rat Hepatoma Cells (H4IIE) were treated with 1/100--1/800 dilutions of each extract and protein synthesis, RNA synthesis, DNA synthesis, Cytochrome P4501A induction, and viability were determined. ∝-CD3 and ∝-IgM-stimulated proliferation of mouse lymphocytes, PWM-stimulated proliferation and PMA-stimulated oxidative burst activity of catfish lymphocytes and phagocytes, respective, were also determined. All extracts were overtly toxic to cell cultures compared to controls at a 1/100 dilution but only aliphatic fractions affected viability at higher dilutions. Aromatic fractions increased protein and RNA synthesis as well as induced P4501A at 1/400 and 1/800 dilutions. Fertilization with P + N increased toxic responses. Lymphocyte proliferation and fish phagocyte responses were more sensitive to aliphatic extracts. This approach may be useful for investigating the toxicity and biological impact of effluents

  19. miR-193b Modulates Resistance to Doxorubicin in Human Breast Cancer Cells by Downregulating MCL-1

    Directory of Open Access Journals (Sweden)

    Jingpei Long

    2015-01-01

    Full Text Available MicroRNAs (miRNAs family, which is involved in cancer development, proliferation, apoptosis, and drug resistance, is a group of noncoding RNAs that modulate the expression of oncogenes and antioncogenes. Doxorubicin is an active cytotoxic agent for breast cancer treatment, but the acquisition of doxorubicin resistance is a common and critical limitation to cancer therapy. The aim of this study was to investigate whether miR-193b mediated the resistance of breast cancer cells to doxorubicin by targeting myeloid cell leukemia-1 (MCL-1. In this study, we found that miR-193b levels were significantly lower in doxorubicin-resistant MCF-7 (MCF-7/DOXR cells than in the parental MCF-7 cells. We observed that exogenous miR-193b significantly suppressed the ability of MCF-7/DOXR cells to resist doxorubicin. It demonstrated that miR-193b directly targeted MCL-1 3′-UTR (3′-Untranslated Regions. Further studies indicated that miR-193b sensitized MCF-7/DOXR cells to doxorubicin through a mechanism involving the downregulation of MCL-1. Together, our findings provide evidence that the modulation of miR-193b may represent a novel therapeutic target for the treatment of breast cancer.

  20. miR-125b acts as a tumor suppressor in chondrosarcoma cells by the sensitization to doxorubicin through direct targeting the ErbB2-regulated glucose metabolism.

    Science.gov (United States)

    Tang, Xian-ye; Zheng, Wei; Ding, Min; Guo, Kai-jin; Yuan, Feng; Feng, Hu; Deng, Bin; Sun, Wei; Hou, Yang; Gao, Lu

    2016-01-01

    Chondrosarcoma is the second most common type of primary bone malignancy in the United States after osteosarcoma. Surgical resections of these tumors are the only effective treatment to chondrosarcoma patients due to their resistance to conventional chemo- and radiotherapy. In this study, miR-125b was found to perform its tumor-suppressor function to inhibit glucose metabolism via the direct targeting of oncogene, ErbB2. We report miR-125b was downregulated in both chondrosarcoma patient samples and cell lines. The total 20 Asian chondrosarcoma patients showed significantly downregulated miR-125b expression compared with normal tissues. Meanwhile, miR-125 was downregulated in chondrosarcoma cells and doxorubicin resistant cells. Overexpression of miR-125 enhanced the sensitivity of both parental and doxorubicin resistant cells to doxorubicin through direct targeting on the ErbB2-mediated upregulation of glycolysis in chondrosarcoma cells. Moreover, restoration of the expression of ErbB2 and glucose metabolic enzymes in miR-125 pretransfected cells recovered the susceptibility to doxorubicin. Our study will provide a novel aspect on the overcoming chemoresistance in human chondrosarcoma cells and may help in the development of therapeutic strategies for the treatments of patients.

  1. Involvement of miR-30c in resistance to doxorubicin by regulating YWHAZ in breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Y. [Department of Central Laboratory, The First Affiliated People’s Hospital, Jiangsu University, Zhenjiang, Jiangsu (China); Shen, H. [Department of Oncology, The First Affiliated People’s Hospital, Jiangsu University, Zhenjiang, Jiangsu (China); Cao, Y. [Department of Central Laboratory, The First Affiliated People’s Hospital, Jiangsu University, Zhenjiang, Jiangsu (China); Li, H. [Department of Central Laboratory, The Fourth Affiliated People’s Hospital, Jiangsu University, Zhenjiang, Jiangsu (China); Qin, R. [Department of Oncology, The First Affiliated People’s Hospital, Jiangsu University, Zhenjiang, Jiangsu (China); Chen, Q. [Department of Central Laboratory, The First Affiliated People’s Hospital, Jiangsu University, Zhenjiang, Jiangsu (China); Long, L. [Department of Oncology, The First Affiliated People’s Hospital, Jiangsu University, Zhenjiang, Jiangsu (China); Zhu, X.L. [Department of Central Laboratory, The Fourth Affiliated People’s Hospital, Jiangsu University, Zhenjiang, Jiangsu (China); Xie, C.J. [Department of Central Laboratory, The First Affiliated People’s Hospital, Jiangsu University, Zhenjiang, Jiangsu (China); Xu, W.L. [Department of Central Laboratory, The Fourth Affiliated People’s Hospital, Jiangsu University, Zhenjiang, Jiangsu (China)

    2014-01-10

    MicroRNAs (miRNAs) are small RNA molecules that modulate gene expression implicated in cancer, which play crucial roles in diverse biological processes, such as development, differentiation, apoptosis, and proliferation. The aim of this study was to investigate whether miR-30c mediated the resistance of breast cancer cells to the chemotherapeutic agent doxorubicin (ADR) by targeting tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein zeta (YWHAZ). miR-30c was downregulated in the doxorubicin-resistant human breast cancer cell lines MCF-7/ADR and MDA-MB-231/ADR compared with their parental MCF-7 and MDA-MB-231 cell lines, respectively. Furthermore, we observed that transfection of an miR-30c mimic significantly suppressed the ability of MCF-7/ADR to resist doxorubicin. Moreover, the anti-apoptotic gene YWHAZ was confirmed as a target of miR-30c by luciferase reporter assay, and further studies indicated that the mechanism for miR-30c on the sensitivity of breast cancer cells involved YWHAZ and its downstream p38 mitogen-activated protein kinase (p38MAPK) pathway. Together, our findings provided evidence that miR-30c was one of the important miRNAs in doxorubicin resistance by regulating YWHAZ in the breast cancer cell line MCF-7/ADR.

  2. DNA origami as a carrier for circumvention of drug resistance.

    Science.gov (United States)

    Jiang, Qiao; Song, Chen; Nangreave, Jeanette; Liu, Xiaowei; Lin, Lin; Qiu, Dengli; Wang, Zhen-Gang; Zou, Guozhang; Liang, Xingjie; Yan, Hao; Ding, Baoquan

    2012-08-15

    Although a multitude of promising anti-cancer drugs have been developed over the past 50 years, effective delivery of the drugs to diseased cells remains a challenge. Recently, nanoparticles have been used as drug delivery vehicles due to their high delivery efficiencies and the possibility to circumvent cellular drug resistance. However, the lack of biocompatibility and inability to engineer spatially addressable surfaces for multi-functional activity remains an obstacle to their widespread use. Here we present a novel drug carrier system based on self-assembled, spatially addressable DNA origami nanostructures that confronts these limitations. Doxorubicin, a well-known anti-cancer drug, was non-covalently attached to DNA origami nanostructures through intercalation. A high level of drug loading efficiency was achieved, and the complex exhibited prominent cytotoxicity not only to regular human breast adenocarcinoma cancer cells (MCF 7), but more importantly to doxorubicin-resistant cancer cells, inducing a remarkable reversal of phenotype resistance. With the DNA origami drug delivery vehicles, the cellular internalization of doxorubicin was increased, which contributed to the significant enhancement of cell-killing activity to doxorubicin-resistant MCF 7 cells. Presumably, the activity of doxorubicin-loaded DNA origami inhibits lysosomal acidification, resulting in cellular redistribution of the drug to action sites. Our results suggest that DNA origami has immense potential as an efficient, biocompatible drug carrier and delivery vehicle in the treatment of cancer.

  3. Methadone, commonly used as maintenance medication for outpatient treatment of opioid dependence, kills leukemia cells and overcomes chemoresistance.

    Science.gov (United States)

    Friesen, Claudia; Roscher, Mareike; Alt, Andreas; Miltner, Erich

    2008-08-01

    The therapeutic opioid drug methadone (d,l-methadone hydrochloride) is the most commonly used maintenance medication for outpatient treatment of opioid dependence. In our study, we found that methadone is also a potent inducer of cell death in leukemia cells and we clarified the unknown mechanism of methadone-induced cell killing in leukemia cells. Methadone inhibited proliferation in leukemia cells and induced cell death through apoptosis induction and activated apoptosis pathways through the activation of caspase-9 and caspase-3, down-regulation of Bcl-x(L) and X chromosome-linked inhibitor of apoptosis, and cleavage of poly(ADP-ribose) polymerase. In addition, methadone induced cell death not only in anticancer drug-sensitive and apoptosis-sensitive leukemia cells but also in doxorubicin-resistant, multidrug-resistant, and apoptosis-resistant leukemia cells, which anticancer drugs commonly used in conventional therapies of leukemias failed to kill. Depending on caspase activation, methadone overcomes doxorubicin resistance, multidrug resistance, and apoptosis resistance in leukemia cells through activation of mitochondria. In contrast to leukemia cells, nonleukemic peripheral blood lymphocytes survived after methadone treatment. These findings show that methadone kills leukemia cells and breaks chemoresistance and apoptosis resistance. Our results suggest that methadone is a promising therapeutic approach not only for patients with opioid dependence but also for patients with leukemias and provide the foundation for new strategies using methadone as an additional anticancer drug in leukemia therapy, especially when conventional therapies are less effective.

  4. Quercetin and doxorubicin co-encapsulated biotin receptor-targeting nanoparticles for minimizing drug resistance in breast cancer.

    Science.gov (United States)

    Lv, Li; Liu, Chunxia; Chen, Chuxiong; Yu, Xiaoxia; Chen, Guanghui; Shi, Yonghui; Qin, Fengchao; Ou, Jiebin; Qiu, Kaifeng; Li, Guocheng

    2016-05-31

    The combination of a chemotherapeutic drug with a chemosensitizer has emerged as a promising strategy for cancers showing multidrug resistance (MDR). Herein we describe the simultaneous targeted delivery of two drugs to tumor cells by using biotin-decorated poly(ethylene glycol)-b-poly(ε-caprolactone) nanoparticles encapsulating the chemotherapeutic drug doxorubicin and the chemosensitizer quercetin (BNDQ). Next, the potential ability of BNDQ to reverse MDR in vitro and in vivo was investigated. Studies demonstrated that BNDQ was more effectively taken up with less efflux by doxorubicin-resistant MCF-7 breast cancer cells (MCF-7/ADR cells) than by the cells treated with the free drugs, single-drug-loaded nanoparticles, or non-biotin-decorated nanoparticles. BNDQ exhibited clear inhibition of both the activity and expression of P-glycoprotein in MCF-7/ADR cells. More importantly, it caused a significant reduction in doxorubicin resistance in MCF-7/ADR breast cancer cells both in vitro and in vivo, among all the groups. Overall, this study suggests that BNDQ has a potential role in the treatment of drug-resistant breast cancer.

  5. The effect of vorinostat on the development of resistance to doxorubicin in neuroblastoma.

    Directory of Open Access Journals (Sweden)

    Timothy B Lautz

    Full Text Available Histone deacetylase (HDAC inhibitors, especially vorinostat, are currently under investigation as potential adjuncts in the treatment of neuroblastoma. The effect of vorinostat co-treatment on the development of resistance to other chemotherapeutic agents is unknown. In the present study, we treated two human neuroblastoma cell lines [SK-N-SH and SK-N-Be(2C] with progressively increasing doses of doxorubicin under two conditions: with and without vorinsotat co-therapy. The resultant doxorubicin-resistant (DoxR and vorinostat-treated doxorubicin resistant (DoxR-v cells were equally resistant to doxorubicin despite significantly lower P-glycoprotein expression in the DoxR-v cells. Whole genome analysis was performed using the Ilumina Human HT-12 v4 Expression Beadchip to identify genes with differential expression unique to the DoxR-v cells. We uncovered a number of genes whose differential expression in the DoxR-v cells might contribute to their resistant phenotype, including hypoxia inducible factor-2. Finally, we used Gene Ontology to categorize the biological functions of the differentially expressed genes unique to the DoxR-v cells and found that genes involved in cellular metabolism were especially affected.

  6. Cytochrome P450 1A expression in midwater fishes: Potential effects of chemical contaminants in remote oceanic zones

    Science.gov (United States)

    Stegeman, John J.; Schlezinger, Jennifer J.; Craddock, James E.; Tillitt, Donald E.

    2001-01-01

    Cytochrome P450 1A (CYP1A) induction is a robust marker for exposure to polynuclear aromatic hydrocarbons and planar halogenated aromatic hydrocarbons that are aryl hydrocarbon receptor agonists. We examined CYP1A expression in mesopelagic fishes from the western North Atlantic. Individuals in 22 species were obtained from slope water and the Sargasso Sea in 1977, 1978, and 1993. Aryl hydrocarbon hydroxylase (AHH), a CYP1A activity, was detected in liver from all species in 1977/78. In some, including Gonostoma elongatum, AHH was inhibited by the CYP1A inhibitor ??-naphthoflavone. CYP1A-dependent ethoxyresorufin O-deethylase (EROD) was detected in liver microsomes of all species in 1993; rates were highest in G. elongatum and Argyropelecus aculeatus. Immunoblot analysis with the CYP1A-specific monoclonal antibody 1-12-3 detected a single microsomal protein band in most 1993 samples; the highest content was in G. elongatum. Immunohistochemical analysis showed CYP1A staining in gill, heart, kidney, and/or liver of several species. Extracts of the 1993 G. elongatum and A. aculeatus, when applied to fish hepatoma cells (PLHC-1) in culture, elicited a significant induction of EROD in those cells. The capacity of the extracts to induce CYP1A correlated with the content of PCBs measured in the same fish (2-4.6 ng/g total body weight). Mesopelagic fish in the western North Atlantic, which experience no direct exposure to surface waters or sediments, are exposed chronically to inducers of CYP1A at levels that appear to be biochemically active in those fish.Cytochrome P450 1A (CYP1A) induction is a robust marker for exposure to polynuclear aromatic hydrocarbons and planar halogenated aromatic hydrocarbons that are awl hydrocarbon receptor agonists. We examined CYP1A expression in mesopelagic fishes from the western North Atlantic. Individuals in 22 species were obtained from slope water and the Sargasso Sea in 1977, 1978, and 1993. Aryl hydrocarbon hydroxylase (AHH), a CYP1A

  7. Dose-response curves for fish MFO induction: How do we interpret different maxima and slopes?

    International Nuclear Information System (INIS)

    Parrott, J.L.

    1995-01-01

    Induction of hepatic mixed function oxygenase (MFO) activity has been useful for screening effluents from pulp mills and oil refineries. Effluents and pure compounds can be assessed by direct fish exposure or by concentration with semipermeable membrane devices (SPMDs) and by measuring MFO in fish liver cell lines exposed to SPMD extracts. In these experiments, both fish and fish cells showed differences in slopes of dose-response curves, and in the maximal ethoxyresorufin-O-deethylase (EROD) activity. For example, TCDD elicits an EROD maxima of over 500 pmol/mg/min in PLHC-1 (Poeciliopsis lucida hepatocellular carcinoma cell line), while pulp mill and oil refinery effluent extracts showed maxima of 40 to 200 pmol/mg/min. Substituted phenanthrenes caused induction maxima of 100 pmol/mg/min. Similarly, in rainbow trout in vivo, TCDD and other chlorinated dioxins and furans induced up to 500 pmol/mg/min, whereas pulp mill and refinery effluents and substituted phenanthrenes produced EROD maxima of up to 100 pmol/mg/min. Differences in the slopes of dose-response curves were also common. In the current assessment of potencies, these diverse response curves are boiled-down to one number, the EC50 or other threshold-type of concentration. Comparisons of EC50s cannot express these differences and instead, ignore them. However, the authors realize there must be a better approach that takes into account these large differences in dose-response curve shape, slope and maxima. Interaction and discussions with modelers in the session will allow them to discuss various approaches to expressing the potencies of MFO inducers in fish

  8. Multimodal transfer of MDR by exosomes in human osteosarcoma.

    Science.gov (United States)

    Torreggiani, Elena; Roncuzzi, Laura; Perut, Francesca; Zini, Nicoletta; Baldini, Nicola

    2016-07-01

    Exosomes are extracellular vesicles released by both normal and tumour cells which are involved in a new intercellular communication pathway by delivering cargo (e.g., proteins, microRNAs, mRNAs) to recipient cells. Tumour-derived exosomes have been shown to play critical roles in different stages of tumour growth and progression. In this study, we investigated the potential role of exosomes to transfer the multidrug resistance (MDR) phenotype in human osteosarcoma cells. Exosomes were isolated by differential centrifugation of culture media from multidrug resistant human osteosarcoma MG-63DXR30 (Exo/DXR) and MG-63 parental cells (Exo/S). Exosome purity was examined by transmission electron microscopy and confirmed by immunoblot analysis for the expression of specific exosomal markers. Our data showed that exosomes derived from doxorubicin-resistant osteosarcoma cells could be taken up into secondary cells and induce a doxorubicin-resistant phenotype. The incubation of osteosarcoma cells with Exo/DXR decreased the sensitivity of parental cells to doxorubicin, while exposure with Exo/S was ineffective. In addition, we demonstrated that Exo/DXR expressed higher levels of MDR-1 mRNA and P-glycoprotein compared to Exo/S (p=0.03). Interestingly, both MDR-1 mRNA and P-gp increased in MG-63 cells after incubation with Exo/DXR, suggesting this as the main mechanism of exosome-mediated transfer of drug resistance. Our findings suggest that multidrug resistant osteosarcoma cells are able to spread their ability to resist the effects of doxorubicin treatment on sensitive cells by transferring exosomes carrying MDR-1 mRNA and its product P-glycoprotein.

  9. Green tea, red wine and lemon extracts reduce experimental tumor growth and cancer drug toxicity.

    Science.gov (United States)

    Zaletok, S P; Gulua, L; Wicker, L; Shlyakhovenko, V A; Gogol, S; Orlovsky, O; Karnaushenko, O V; Verbinenko, A; Milinevska, V; Samoylenko, O; Todor, I; Turmanidze, T

    2015-12-01

    To evaluate antitumor effect of plant polyphenol extracts from green tea, red wine lees and/or lemon peel alone and in combination with antitumor drugs on the growth of different transplanted tumors in experimental animals. Green tea extract (GTE) was prepared from green tea infusion. GTE-based composites of red wine (GTRW), lemon peel (GTRWL) and/or NanoGTE as well as corresponding nanocomposites were prepared. The total polyphenolics of the different GTE-based extracts ranged from 18.0% to 21.3%. The effects of GTE-based extracts were studied in sarcoma 180, Ehrlich carcinoma, B16 melanoma, Ca755 mammary carcinoma, P388 leukemia, L1210 leukemia, and Guerin carcinoma (original, cisplatin-resistant and doxorubicin-resistant variants). The extracts were administered as 0.1% solution in drinking water (0.6-1.0 mg by total polyphenolics per mouse per day and 4.0-6.3 mg per rat per day). Tumor growth inhibition (TGI) in mice treated with NanoGTE, cisplatin or cisplatin + NanoGTE was 27%, 55% and 78%, respectively, in Sarcoma 180%, 21%, 45% and 59%, respectively, in Ehrlich carcinoma; and 8%, 13% and 38%, respectively in B16 melanoma. Composites of NanoGTE, red wine, and lemon peel (NanoGTRWL) enhanced the antitumor effects of cyclophosphamide in mice with Ca755 mammary carcinoma. The treatment with combination of NanoGTE and inhibitors of polyamines (PA) synthesis (DFMO + MGBG) resulted in significant TGI of P388 leukemia (up to 71%) and L1210 leukemia. In rats transplanted with Guerin carcinoma (parental strain), treatment with GTRW or GTE alone resulted in 25-28% TGI vs. 55-68% TGI in cisplatin-treated animals. The inhibition observed in the case of combination of GTE or GTRW with cisplatin was additive giving 81-88% TGI. Similar effects were observed when combinations of the cytostatics with GTE (or NanoGTE) were tested against cisplatin- or doxorubicin-resistant Guerin carcinoma. Moreover, the plant extracts lowered side toxicity of the drugs. Treatment with GTE

  10. Direct interaction between verapamil and doxorubicin causes the lack of reversal effect of verapamil on P-glycoprotein mediated resistance to doxorubicin in vitro using L1210/VCR cells

    International Nuclear Information System (INIS)

    Breier, A.; Drobna, Z.; Barancik, M.

    1998-01-01

    Mouse leukemic cell sub-line L 1210/VCR exerts expressive multidrug resistance (MDR) that is mediated by P-glycoprotein. Cells originally adapted to vincristine are also extremely resistant to doxorubicin. Resistance to both vincristine and doxorubicin is connected with depression of drug uptake. While resistance of L 121 O cells to vincristine could be reversed by verapamil as chemo-sensitizer, resistance of cells to doxorubicin was insensitive to verapamil. Action of verapamil (well-known inhibitor of PGP activity) on multidrug resistance was often used as evidence that MDR is mediated by PGP. From this point it may be possible that the resistance of L1210/VCR cells to vincristine is mediated by PGP and the resistance to doxorubicin is mediated by other PGP-independent system. Another and more probable explanation of different effect of verapamil on resistance of L1210/VCR cells to vincristine and doxorubicin may be deduced from the following fact: Using UV spectroscopy we found that doxorubicin dissolved in water buffered medium interacts effectively with verapamil. This interaction may be responsible for the decrease of concentration of both drugs in free effective form and consequently for higher survival of cells. In contrast to doxorubicin vincristine does not give any interaction with verapamil that is measurable by UV spectroscopy and resistance of L1210/VCR cells to vincristine may be fully reversed by verapamil. (authors)

  11. Synthesis and evaluation of indole-based chalcones as inducers of methuosis, a novel type of non-apoptotic cell death

    Science.gov (United States)

    Robinson, Michael W.; Overmeyer, Jean H.; Young, Ashley M.; Erhardt, Paul W.; Maltese, William A.

    2012-01-01

    Methuosis is a novel caspase-independent form of cell death in which massive accumulation of vacuoles derived from macropinosomes ultimately causes cells to detach from the substratum and rupture. We recently described a chalcone-like compound, 3-(2-methyl-1H indol-3-yl)-1-(4-pyridinyl)-2-propen-1-one (i.e. MIPP), which can induce methuosis in glioblastoma and other types of cancer cells. Herein we describe the synthesis and structure-activity relationships of a directed library of related compounds, providing insights into the contributions of the two aryl ring systems and highlighting a potent derivative, 3-(5-methoxy, 2-methyl-1H-indol-3-yl)-1-(4-pyridinyl)-2-propen-1-one (i.e. MOMIPP) that can induce methuosis at low μM concentrations. We have also generated biologically active azide derivatives that may be useful for future studies aimed at identifying the protein targets of MOMIPP by photoaffinity labeling techniques. The potential significance of these studies is underscored by the finding that MOMIPP effectively reduces the growth and viability of temozolomide-resistant glioblastoma and doxorubicin-resistant breast cancer cells. Thus, it may serve as a prototype for drugs that could be used to trigger death by methuosis in cancers that are resistant to conventional forms of cell death (e.g. apoptosis). PMID:22335538

  12. Synthesis and evaluation of indole-based chalcones as inducers of methuosis, a novel type of nonapoptotic cell death.

    Science.gov (United States)

    Robinson, Michael W; Overmeyer, Jean H; Young, Ashley M; Erhardt, Paul W; Maltese, William A

    2012-03-08

    Methuosis is a novel caspase-independent form of cell death in which massive accumulation of vacuoles derived from macropinosomes ultimately causes cells to detach from the substratum and rupture. We recently described a chalcone-like compound, 3-(2-methyl-1H-indol-3-yl)-1-(4-pyridinyl)-2-propen-1-one (i.e., MIPP), which can induce methuosis in glioblastoma and other types of cancer cells. Herein, we describe the synthesis and structure-activity relationships of a directed library of related compounds, providing insights into the contributions of the two aryl ring systems and highlighting a potent derivative, 3-(5-methoxy, 2-methyl-1H-indol-3-yl)-1-(4-pyridinyl)-2-propen-1-one (i.e., MOMIPP) that can induce methuosis at low micromolar concentrations. We have also generated biologically active azide derivatives that may be useful for future studies aimed at identifying the protein targets of MOMIPP by photoaffinity labeling techniques. The potential significance of these studies is underscored by the finding that MOMIPP effectively reduces the growth and viability of Temozolomide-resistant glioblastoma and doxorubicin-resistant breast cancer cells. Thus, it may serve as a prototype for drugs that could be used to trigger death by methuosis in cancers that are resistant to conventional forms of cell death (e.g., apoptosis).

  13. Ecdysteroids Sensitize MDR and Non-MDR Cancer Cell Lines to Doxorubicin, Paclitaxel, and Vincristine but Tend to Protect Them from Cisplatin

    Directory of Open Access Journals (Sweden)

    Ana Martins

    2015-01-01

    Full Text Available Ecdysteroids, analogs of the insect molting hormone, are known for their various mild, nonhormonal bioactivities in mammals. Previously, we reported that less-polar ecdysteroids can modulate the doxorubicin resistance of a multidrug resistant (MDR mouse lymphoma cell line expressing the human ABCB1 transporter. Here, we describe the ability of 20-hydroxyecdysone (1 and its mono- (2 and diacetonide (3 derivatives to sensitize various MDR and non-MDR cancer cell lines towards doxorubicin, paclitaxel, vincristine, or cisplatin. Drug IC50 values with or without ecdysteroid were determined by MTT assay. Compound 3 significantly sensitized all cell lines to each chemotherapeutic except for cisplatin, whose activity was decreased. In order to overcome solubility and stability issues for the future in vivo administration of compound 3, liposomal formulations were developed. By means of their combination index values obtained via checkerboard microplate method, a formulation showed superior activity to that of compound 3 alone. Because ecdysteroids act also on non-ABCB1 expressing (sensitive cell lines, our results demonstrate that they do not or not exclusively exert their adjuvant anticancer activity as ABCB1 inhibitors, but other mechanisms must be involved, and they opened the way towards their in vivo bioactivity testing against various cancer xenografts.

  14. Interaction of Flavonoids from Woodwardia unigemmata with Bovine Serum Albumin (BSA): Application of Spectroscopic Techniques and Molecular Modeling Methods.

    Science.gov (United States)

    Ma, Rui; Pan, Hong; Shen, Tao; Li, Peng; Chen, Yanan; Li, Zhenyu; Di, Xiaxia; Wang, Shuqi

    2017-08-09

    Phytochemical investigation on the methanol extract of Woodwardia unigemmata resulted in the isolation of seven flavonoids, including one new flavonol acylglycoside ( 1 ). The structures of these compounds were elucidated on the basis of extensive spectroscopic analysis and comparison of literature data. The multidrug resistance (MDR) reversing activity was evaluated for the isolated compounds using doxorubicin-resistant K562/A02 cells model. Compound 6 showed comparable MDR reversing effect to verapamil. Furthermore, the interaction between compounds and bovine serum albumin (BSA) was investigated by spectroscopic methods, including steady-state fluorescence, synchronous fluorescence, circular dichroism (CD) spectroscopies, and molecular docking approach. The experimental results indicated that the seven flavonoids bind to BSA by static quenching mechanisms. The negative ΔH and ΔS values indicated that van der Waals interactions and hydrogen bonds contributed in the binding of compounds 2 - 6 to BSA. In the case of compounds 1 and 7 systems, the hydrophobic interactions play a major role. The binding of compounds to BSA causes slight changes in the secondary structure of BSA. There are two binding sites of compound 6 on BSA and site I is the main site according to the molecular docking studies and the site marker competitive binding assay.

  15. Cytotoxicity and apoptosis induced by alfalfa (Medicago sativa) leaf extracts in sensitive and multidrug-resistant tumor cells.

    Science.gov (United States)

    Gatouillat, Grégory; Magid, Abdulmagid Alabdul; Bertin, Eric; Okiemy-Akeli, Marie-Genevieve; Morjani, Hamid; Lavaud, Catherine; Madoulet, Claudie

    2014-01-01

    Alfalfa (Medicago sativa) has been used to cure a wide variety of ailments. However, only a few studies have reported its anticancer effects. In this study, extracts were obtained from alfalfa leaves and their cytotoxic effects were assessed on several sensitive and multidrug-resistant tumor cells lines. Using the mouse leukaemia P388 cell line and its doxorubicin-resistant counterpart (P388/DOX), we showed that the inhibition of cell growth induced by alfalfa leaf extracts was mediated through the induction of apoptosis, as evidenced by DNA fragmentation analysis. The execution of programmed cell death was achieved via the activation of caspase-3, leading to PARP cleavage. Fractionation of toluene extract (To-1), the most active extract obtained from crude extract, led to the identification of 3 terpene derivatives and 5 flavonoids. Among them, (-)-medicarpin, (-)-melilotocarpan E, millepurpan, tricin, and chrysoeriol showed cytotoxic effects in P388 as well as P388/DOX cells. These results demonstrate that alfalfa leaf extract may have interesting potential in cancer chemoprevention and therapy.

  16. Metabolic changes during development of Walker-256 carcinosarcoma resistance to doxorubicin.

    Science.gov (United States)

    Todor, I N; Lukyanova, N Yu; Shvets, Yu V; Lozovska, Yu V; Chekhun, V F

    2015-03-01

    To study indices of energy metabolism, content of K(+) and Mg(++) both in peripheral blood and in Walker-256 carcinosarcoma during development of resistance to doxorubicin. Resistance of Walker-256 carcinosarcoma to doxorubicin has been developed through 12 subsequent transplantations of tumor after the chemotherapy. Parental strain was inhibited by drug by 65%, while transitional resistant substrains - by 30% and 2%, respectively. Determination of biochemical indices in blood serum and homogenates of tumor tissue, level of potassium, magnesium, lactate, glucose, activities of lactate dehydrogenase and glucose-6-phosphate dehydrogenase was performed with the help of biochemical and immune-enzyme analyzer GBG ChemWell 2990 (USA) using standard kits. Polarography was used to determine indices of mitochondrial oxidative phosphorylation. Study of mitochondrial membrane potential was carried out on flow cytometer Beckman Coulter Epics XL using dye JC-1. It has been determined that development of drug resistance causes the decrease of K(+), Mg(++), glucose content in blood serum and increase of these indices in tumor tissue. At the same time, gradual tumor's loss of sensitivity is characterized by decrease of glycolysis activity in it and activation of mitochondrial oxidative phosphorylation and pentose phosphate pathway of glucose degradation, which causes more intensive formation of NADPH. Development of drug resistance of tumor causes certain metabolic changes in organism and tumor. Further study of such changes will make possible to determine tumor and extratumor markers of resistance.

  17. Remodulating effect of doxorubicin on the state of iron-containing proteins, and redox characteristics of tumor with allowance for its sensitivity to cytostatic agents.

    Science.gov (United States)

    Chekhun, V F; Lozovska, Yu V; Burlaka, A P; Ganusevich, L I; Shvets, Yu V; Lukyanova, N Yu; Todor, I M; Tregubova, N A; Naleskina, L A

    2016-01-01

    The study was aimed at determining the changes of metal-containing proteins in blood serum and tumor tissue of animals with parental and doxorubicin-resistant strains of Walker-256 carcinosarcoma before and after the cytostatic administration. It has been shown that upon doxorubicin action the levels of total iron and transferrin in the tissues from the both groups of animals decreased while that of ferritine simultaneously increased with more pronounced pattern in the group of animals with resistant tumor strain. It has been shown that upon the action of doxorubicin in tumor tissue of animals with different sensitivity to the cytostatic there could be observed oppositely directed changes in the redox state of these cells that in turn determined the content of “ free iron” complexes, RO S generation and concentration of active forms of matrix metaloproteinase- 2 and matrix metaloproteinase-9, namely, the increase of these indexes in animals with parental strain and their decrease in animals with the resistant one. So, our study has demonstrated the remodulating effect of doxorubicin on the state of metal-containing proteins and redox characteristics of tumor dependent on its sensitivity to cytostatic, at the levels of the tumor and an organism. These data may serve as a criterion for the development of programs for the correction of malfunction of iron metabolism aimed at elevating tumor sensitivity to cytostatic agents.

  18. Metalloproteins during development of Walker-256 carcinosarcoma resistant phenotype

    Directory of Open Access Journals (Sweden)

    V. F. Chekhun

    2015-04-01

    Full Text Available The study was focused on the detection of changes in serum and tumor metal-containing proteins in animals during development of doxorubicin-resistant phenotype in malignant cells after 12 courses of chemotherapy. We found that on every stage of resistance development there was a significant increase in content of ferritin and transferrin proteins (which take part in iron traffick and storage in Walker-256 carcinosarcoma tissue. We observed decreased serum ferritin levels at the beginning stage of the resistance development and significant elevation of this protein levels in the cases with fully developed resistance phenotype. Transferrin content showed changes opposite to that of ferritin. During the development of resistance phenotype the tumor tissue also exhibited increased ‘free iron’ concentration that putatively correlate with elevation of ROS generation and levels of MMP-2 and MMP-9 active forms. The tumor non-protein thiol content increases gradually as well. The serum of animals with early stages of resistance phenotype development showed high ceruloplasmin activity and its significant reduction after loss of tumor sensitivity to doxorubicin. Therefore, the development of resistance phenotype in Walker-256 carcinosarcoma is accompanied by both the deregulation of metal-containing proteins in serum and tumor tissue and by the changes in activity of antioxidant defense system. Thus, the results of this study allow us to determine the spectrum of metal-containing proteins that are involved in the development of resistant tumor phenotype and that may be targeted for methods for doxorubicin sensitivity correction therapy.

  19. Expression of Potential Cancer Stem Cell Marker ABCG2 is Associated with Malignant Behaviors of Hepatocellular Carcinoma

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    Guang Zhang

    2013-01-01

    Full Text Available Background. Despite improvement in treatment, the prognosis of hepatocellular carcinoma (HCC remains disastrous. Cancer stem cells (CSCs may be responsible for cancer malignant behaviors. ATP-binding cassette, subfamily G, member 2 (ABCG2 is widely expressed in both normal and cancer stem cells and may play an important role in cancer malignant behaviors. Methods. The expression of ABCG2 in HCC tissues and SMMC-7721 cells was examined, and the relevance of ABCG2 expression with clinical characteristics was analyzed. ABCG2+ and ABCG2− cells were sorted, and the potential of tumorigenicity was determined. Expression level of ABCG2 was manipulated by RNA interference and overexpression. Malignant behaviors including proliferation, drug resistance, migration, and invasion were studied in vitro. Results. Expression of ABCG2 was found in a minor group of cells in HCC tissues and cell lines. ABCG2 expression showed tendencies of association with unfavorable prognosis factors. ABCG2 positive cells showed a superior tumorigenicity. Upregulation of ABCG2 enhanced the capacity of proliferation, doxorubicin resistance, migration, and invasion potential, while downregulation of ABCG2 significantly decreased these malignant behaviors. Conclusion. Our results indicate that ABCG2 is a potential CSC marker for HCC. Its expression level has a close relationship with tumorigenicity, proliferation, drug resistance, and metastasis ability.

  20. MicroRNA181a Is Overexpressed in T-Cell Leukemia/Lymphoma and Related to Chemoresistance

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    Zi-Xun Yan

    2015-01-01

    Full Text Available MicroRNAs (miRs play an important role in tumorogenesis and chemoresistance in lymphoid malignancies. Comparing with reactive hyperplasia, miR181a was overexpressed in 130 patients with T-cell leukemia/lymphoma, including acute T-cell lymphoblastic leukemia (n=32, T-cell lymphoblastic lymphoma (n=16, peripheral T-cell lymphoma, not otherwise specified (n=45, anaplastic large cell lymphoma (n=15, and angioimmunoblastic T-cell lymphoma (n=22. Irrespective to histological subtypes, miR181a overexpression was associated with increased AKT phosphorylation. In vitro, ectopic expression of miR181a in HEK-293T cells significantly enhanced cell proliferation, activated AKT, and conferred cell resistance to doxorubicin. Meanwhile, miR181a expression was upregulated in Jurkat cells, along with AKT activation, during exposure to chemotherapeutic agents regularly applied to T-cell leukemia/lymphoma treatment, such as doxorubicin, cyclophosphamide, cytarabine, and cisplatin. Isogenic doxorubicin-resistant Jurkat and H9 cells were subsequently developed, which also presented with miR181a overexpression and cross-resistance to cyclophosphamide and cisplatin. Meanwhile, specific inhibition of miR181a enhanced Jurkat and H9 cell sensitivity to chemotherapeutic agents, further indicating that miR181a was involved in acquired chemoresistance. Collectively, miR181a functioned as a biomarker of T-cell leukemia/lymphoma through modulation of AKT pathway. Related to tumor cell chemoresistance, miR181a could be a potential therapeutic target in treating T-cell malignancies.

  1. Release of the cyano moiety in the crystal structure of N-cyanomethyl-N-(2-methoxyethyl)-daunomycin complexed with d(CGATCG).

    Science.gov (United States)

    Saminadin, P; Dautant, A; Mondon, M; Langlois D'estaintot, B; Courseille, C; Précigoux, G

    2000-01-01

    Doxorubicin is among the most widely used anthracycline in cancer chemotherapy. In an attempt to avoid the cardiotoxicity and drug resistance of doxorubicin therapy, several analogues were synthesized. The cyanomorpholinyl derivative is the most cytotoxic. They differ greatly from their parent compound in their biological and pharmacological properties, inducing cross-links in drug DNA complexes. The present study concerns N-cyanomethyl-N-(2-methoxyethyl)-daunomycin (CMDa), a synthetic analogue of cyanomorpholino-daunomycin. Compared to doxorubicin, CMDa displays a cytotoxic activity on L1210 leukemia cells at higher concentration but is effective on doxorubicin resistant cells. The results of fluorescence quenching experiments as well as the melting temperature (DeltaTm = 7.5 degrees C) studies are consistent with a drug molecule which intercalates between the DNA base pairs and stabilizes the DNA double helix. The crystal structure of CMDa complexed to the hexanucleotide d(CGATCG) has been determined at 1.5 A resolution. The complex crystallizes in the space group P41212 and is similar to other anthracycline-hexanucleotide complexes. In the crystal state, the observed densities indicate the formation of N-hydroxymethyl-N-(2-methoxyethyl)-daunomycin (HMDa) with the release of the cyano moiety without DNA alkylation. The formation of this degradation compound is discussed in relation with other drug modifications when binding to DNA. Comparison with two other drug-DNA crystal structures suggests a correlation between a slight change in DNA conformation and the nature of the amino sugar substituents at the N3' position located in the minor groove.

  2. 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

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    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.

  3. TTFields alone and in combination with chemotherapeutic agents effectively reduce the viability of MDR cell sub-lines that over-express ABC transporters

    International Nuclear Information System (INIS)

    Schneiderman, Rosa S; Shmueli, Esther; Kirson, Eilon D; Palti, Yoram

    2010-01-01

    Exposure of cancer cells to chemotherapeutic agents may result in reduced sensitivity to structurally unrelated agents, a phenomenon known as multidrug resistance, MDR. The purpose of this study is to investigate cell growth inhibition of wild type and the corresponding MDR cells by Tumor Treating Fields - TTFields, a new cancer treatment modality that is free of systemic toxicity. The TTFields were applied alone and in combination with paclitaxel and doxorubicin. Three pairs of wild type/MDR cell lines, having resistivity resulting from over-expression of ABC transporters, were studied: a clonal derivative (C11) of parental Chinese hamster ovary AA8 cells and their emetine-resistant sub-line Emt R1 ; human breast cancer cells MCF-7 and their mitoxantrone-resistant sub lines MCF-7/Mx and human breast cancer cells MDA-MB-231 and their doxorubicin resistant MDA-MB-231/Dox cells. TTFields were applied for 72 hours with and without the chemotherapeutic agents. The numbers of viable cells in the treated cultures and the untreated control groups were determined using the XTT assay. Student t-test was applied to asses the significance of the differences between results obtained for each of the three cell pairs. TTFields caused a similar reduction in the number of viable cells of wild type and MDR cells. Treatments by TTFields/drug combinations resulted in a similar increased reduction in cell survival of wild type and MDR cells. TTFields had no effect on intracellular doxorubicin accumulation in both wild type and MDR cells. The results indicate that TTFields alone and in combination with paclitaxel and doxorubicin effectively reduce the viability of both wild type and MDR cell sub-lines and thus can potentially be used as an effective treatment of drug resistant tumors

  4. Evaluation of the P-glycoprotein- and breast cancer resistance protein-mediated brain penetration of 11C-labeled topotecan using small-animal positron emission tomography

    International Nuclear Information System (INIS)

    Yamasaki, Tomoteru; Fujinaga, Masayuki; Kawamura, Kazunori; Hatori, Akiko; Yui, Joji; Nengaki, Nobuki; Ogawa, Masanao; Yoshida, Yuichiro; Wakizaka, Hidekatsu; Yanamoto, Kazuhiko; Fukumura, Toshimitsu; Zhang Mingrong

    2011-01-01

    Introduction: Topotecan (TPT) is a camptothecin derivative and is an anticancer drug working as a topoisomerase-I-specific inhibitor. But TPT cannot penetrate through the blood-brain barrier. In this study, we synthesized a new positron emission tomography (PET) probe, [ 11 C]TPT, to evaluate the P-glycoprotein (Pgp)- and breast cancer resistance protein (BCRP)-mediated brain penetration of [ 11 C]TPT using small-animal PET. Methods: [ 11 C]TPT was synthesized by the reaction of a desmethyl precursor with [ 11 C]CH 3 I. In vitro study using [ 11 C]TPT was carried out in MES-SA and doxorubicin-resistant MES-SA/Dx5 cells in the presence or absence of elacridar, a specific inhibitor for Pgp and BCRP. The biodistribution of [ 11 C]TPT was determined using small-animal PET and the dissection method in mice. Results: The transport of [ 11 C]TPT to the extracellular side was determined in MES-SA/Dx5 cells exhibiting the expressions of Pgp and BCRP at high levels. This transport was inhibited by coincubation with elacridar. In Mdr1a/b -/- Bcrp1 -/- mice, PET results indicated that the brain uptake of [ 11 C]TPT was about two times higher than that in wild-type mice. Similarly, the brain penetration of [ 11 C]TPT in wild-type mice was increased by treatment with elacridar. The radioactivity in the brain of elacridar-treated mice was maintained at a certain level after the injection of [ 11 C]TPT, although the radioactivity in the blood decreased with time. Conclusions: We demonstrated the increase of brain penetration of [ 11 C]TPT by deficiency and inhibition of Pgp and BCRP functions using small-animal PET in mice.

  5. Evaluation of the P-glycoprotein- and breast cancer resistance protein-mediated brain penetration of {sup 11}C-labeled topotecan using small-animal positron emission tomography

    Energy Technology Data Exchange (ETDEWEB)

    Yamasaki, Tomoteru; Fujinaga, Masayuki; Kawamura, Kazunori; Hatori, Akiko; Yui, Joji [Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Nengaki, Nobuki; Ogawa, Masanao; Yoshida, Yuichiro [Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); SHI Accelerator Service, Ltd., Tokyo 141-8686 (Japan); Wakizaka, Hidekatsu [Department of Biophysics, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Yanamoto, Kazuhiko [Division of Health Sciences, Graduate School of Medicine, Osaka University, Osaka 565-0871 (Japan); Fukumura, Toshimitsu [Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan); Zhang Mingrong, E-mail: zhang@nirs.go.jp [Department of Molecular Probes, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba 263-8555 (Japan)

    2011-07-15

    Introduction: Topotecan (TPT) is a camptothecin derivative and is an anticancer drug working as a topoisomerase-I-specific inhibitor. But TPT cannot penetrate through the blood-brain barrier. In this study, we synthesized a new positron emission tomography (PET) probe, [{sup 11}C]TPT, to evaluate the P-glycoprotein (Pgp)- and breast cancer resistance protein (BCRP)-mediated brain penetration of [{sup 11}C]TPT using small-animal PET. Methods: [{sup 11}C]TPT was synthesized by the reaction of a desmethyl precursor with [{sup 11}C]CH{sub 3}I. In vitro study using [{sup 11}C]TPT was carried out in MES-SA and doxorubicin-resistant MES-SA/Dx5 cells in the presence or absence of elacridar, a specific inhibitor for Pgp and BCRP. The biodistribution of [{sup 11}C]TPT was determined using small-animal PET and the dissection method in mice. Results: The transport of [{sup 11}C]TPT to the extracellular side was determined in MES-SA/Dx5 cells exhibiting the expressions of Pgp and BCRP at high levels. This transport was inhibited by coincubation with elacridar. In Mdr1a/b{sup -/-}Bcrp1{sup -/-} mice, PET results indicated that the brain uptake of [{sup 11}C]TPT was about two times higher than that in wild-type mice. Similarly, the brain penetration of [{sup 11}C]TPT in wild-type mice was increased by treatment with elacridar. The radioactivity in the brain of elacridar-treated mice was maintained at a certain level after the injection of [{sup 11}C]TPT, although the radioactivity in the blood decreased with time. Conclusions: We demonstrated the increase of brain penetration of [{sup 11}C]TPT by deficiency and inhibition of Pgp and BCRP functions using small-animal PET in mice.

  6. NFκBP65 transcription factor modulates resistance to doxorubicin through ABC transporters in breast cancer.

    Science.gov (United States)

    Velaei, Kobra; Samadi, Nasser; Soltani, Sina; Barazvan, Balal; Soleimani Rad, Jafar

    2017-07-01

    Shedding light on chemoresistance biology of breast cancer could contribute to enhance the clinical outcome. Intrinsic or acquired resistance to chemotherapy is a major problem in breast cancer treatment. The NFκB pathway by siRNAP65 and JSH-23 as a translocational inhibitor of NFκBP65 in the doxorubicin-resistant MCF-7 (MCF-7/Dox) and MCF-7 cells was blocked. Then, the ABC transporter expression and function were assessed by real-time qRT-PCR and flow cytometry, respectively. Induction of apoptosis was evaluated after inhibition of the NFΚB pathway as well. Our study underlined the upregulation of NFκBP65 and anti-apoptotic Bcl-2 and downregulation of pro-apoptotic Bax in the MCF-7/Dox cells compared with control MCF-7 cells. Here, we showed that interplay between nuclear factor kappa B P65 (NFkBP65) as a transcriptional regulator and ABC transporters in the MCF-7/Dox cancer cells. We found that inhibition of the elevated expression of NFκBP65 in the resistant breast cancer, whether translocational inhibition or silencing by siRNA, decreased the expression and function of MDR1 and MRP1 efflux pumps. Furthermore, the blockade of NFκBP65 promoted apoptosis via modulating Bcl-2 and BAX expression. After inhibition of the NFκBP65 signaling pathway, elevated baseline expression of survival Bcl-2 gene in the resistant breast cells significantly decreased. Suppression of the NFκB pathway has a profound dual impact on promoting the intrinsic apoptotic pathway and reducing ABC transporter function and expression, which are some of the chemoresistance features. It was speculated that the NFκB pathway directly acts on doxorubicin-induced MDR1 and MRP1 expression in MCF-7/Dox cells.

  7. Treatment of Multidrug-Resistant Leukemia Cells by Novel Artemisinin-, Egonol-, and Thymoquinone-Derived Hybrid Compounds

    Directory of Open Access Journals (Sweden)

    Lisa Gruber

    2018-04-01

    Full Text Available Two major obstacles for successful cancer treatment are the toxicity of cytostatics and the development of drug resistance in cancer cells during chemotherapy. Acquired or intrinsic drug resistance is responsible for almost 90% of treatment failure. For this reason, there is an urgent need for new anticancer drugs with improved efficacy against cancer cells, and with less toxicity on normal cells. There are impressive examples demonstrating the success of natural plant compounds to fight cancer, such as Vinca alkaloids, taxanes, and anthracyclines. Artesunic acid (ARTA, a drug for malaria treatment, also exerts cytotoxic activity towards cancer cells. Multidrug resistance often results from drug efflux pumps (ABC-transporters that reduce intracellular drug levels. Hence, it would be interesting to know, whether ARTA could overcome drug resistance of tumor cells, and in what way ABC-transporters are involved. Different derivatives showing improved features concerning cytotoxicity and pharmacokinetic behavior have been developed. Considering both drug sensitivity and resistance, we chose a sensitive and a doxorubicin-resistant leukemia cell line and determined the killing effect of ARTA on these cells. Molecular docking and doxorubicin efflux assays were performed to investigate the interaction of the derivatives with P-glycoprotein. Using single-cell gel electrophoresis (alkaline comet assay, we showed that the derivatives of ARTA induce DNA breakage and accordingly programmed cell death, which represents a promising strategy in cancer treatment. ARTA activated apoptosis in cancer cells by the iron-mediated generation of reactive oxygen species (ROS. In conclusion, ARTA derivatives may bear the potential to be further developed as anticancer drugs.

  8. Improved Tumor-Specific Drug Accumulation by Polymer Therapeutics with pH-Sensitive Drug Release Overcomes Chemotherapy Resistance.

    Science.gov (United States)

    Heinrich, Anne-Kathrin; Lucas, Henrike; Schindler, Lucie; Chytil, Petr; Etrych, Tomáš; Mäder, Karsten; Mueller, Thomas

    2016-05-01

    The success of chemotherapy is limited by poor selectivity of active drugs combined with occurrence of tumor resistance. New star-like structured N-(2-hydroxypropyl) methacrylamide (HPMA) copolymer-based drug delivery systems containing doxorubicin attached via a pH-sensitive hydrazone bond were designed and investigated for their ability to overcome chemotherapy resistance. These conjugates combine two strategies to achieve a high drug concentration selectively at the tumor site: (I) high accumulation by passive tumor targeting based on enhanced permeability and retention effect and (II) pH-sensitive site-specific drug release due to an acidic tumor microenvironment. Mice bearing doxorubicin-resistant xenograft tumors were treated with doxorubicin, PBS, poly HPMA (pHPMA) precursor or pHPMA-doxorubicin conjugate at different equivalent doses of 5 mg/kg bodyweight doxorubicin up to a 7-fold total dose using different treatment schedules. Intratumoral drug accumulation was analyzed by fluorescence imaging utilizing intrinsic fluorescence of doxorubicin. Free doxorubicin induced significant toxicity but hardly any tumor-inhibiting effects. Administering at least a 3-fold dose of pHPMA-doxorubicin conjugate was necessary to induce a transient response, whereas doses of about 5- to 6-fold induced strong regressions. Tumors completely disappeared in some cases. The onset of response was differential delayed depending on the tumor model, which could be ascribed to distinct characteristics of the microenvironment. Further fluorescence imaging-based analyses regarding underlying mechanisms of the delayed response revealed a related switch to a more supporting intratumoral microenvironment for effective drug release. In conclusion, the current study demonstrates that the concept of tumor site-restricted high-dose chemotherapy is able to overcome therapy resistance. Mol Cancer Ther; 15(5); 998-1007. ©2016 AACR. ©2016 American Association for Cancer Research.

  9. Insights into the transposable mobilome of Paracoccus spp. (Alphaproteobacteria).

    Science.gov (United States)

    Dziewit, Lukasz; Baj, Jadwiga; Szuplewska, Magdalena; Maj, Anna; Tabin, Mateusz; Czyzkowska, Anna; Skrzypczyk, Grazyna; Adamczuk, Marcin; Sitarek, Tomasz; Stawinski, Piotr; Tudek, Agnieszka; Wanasz, Katarzyna; Wardal, Ewa; Piechucka, Ewa; Bartosik, Dariusz

    2012-01-01

    Several trap plasmids (enabling positive selection of transposition events) were used to identify a pool of functional transposable elements (TEs) residing in bacteria of the genus Paracoccus (Alphaproteobacteria). Complex analysis of 25 strains representing 20 species of this genus led to the capture and characterization of (i) 37 insertion sequences (ISs) representing 9 IS families (IS3, IS5, IS6, IS21, IS66, IS256, IS1182, IS1380 and IS1634), (ii) a composite transposon Tn6097 generated by two copies of the ISPfe2 (IS1634 family) containing two predicted genetic modules, involved in the arginine deiminase pathway and daunorubicin/doxorubicin resistance, (iii) 3 non-composite transposons of the Tn3 family, including Tn5393 carrying streptomycin resistance and (iv) a transposable genomic island TnPpa1 (45 kb). Some of the elements (e.g. Tn5393, Tn6097 and ISs of the IS903 group of the IS5 family) were shown to contain strong promoters able to drive transcription of genes placed downstream of the target site of transposition. Through the application of trap plasmid pCM132TC, containing a promoterless tetracycline resistance reporter gene, we identified five ways in which transposition can supply promoters to transcriptionally silent genes. Besides highlighting the diversity and specific features of several TEs, the analyses performed in this study have provided novel and interesting information on (i) the dynamics of the process of transposition (e.g. the unusually high frequency of transposition of TnPpa1) and (ii) structural changes in DNA mediated by transposition (e.g. the generation of large deletions in the recipient molecule upon transposition of ISPve1 of the IS21 family). We also demonstrated the great potential of TEs and transposition in the generation of diverse phenotypes as well as in the natural amplification and dissemination of genetic information (of adaptative value) by horizontal gene transfer, which is considered the driving force of bacterial

  10. Insights into the transposable mobilome of Paracoccus spp. (Alphaproteobacteria.

    Directory of Open Access Journals (Sweden)

    Lukasz Dziewit

    Full Text Available Several trap plasmids (enabling positive selection of transposition events were used to identify a pool of functional transposable elements (TEs residing in bacteria of the genus Paracoccus (Alphaproteobacteria. Complex analysis of 25 strains representing 20 species of this genus led to the capture and characterization of (i 37 insertion sequences (ISs representing 9 IS families (IS3, IS5, IS6, IS21, IS66, IS256, IS1182, IS1380 and IS1634, (ii a composite transposon Tn6097 generated by two copies of the ISPfe2 (IS1634 family containing two predicted genetic modules, involved in the arginine deiminase pathway and daunorubicin/doxorubicin resistance, (iii 3 non-composite transposons of the Tn3 family, including Tn5393 carrying streptomycin resistance and (iv a transposable genomic island TnPpa1 (45 kb. Some of the elements (e.g. Tn5393, Tn6097 and ISs of the IS903 group of the IS5 family were shown to contain strong promoters able to drive transcription of genes placed downstream of the target site of transposition. Through the application of trap plasmid pCM132TC, containing a promoterless tetracycline resistance reporter gene, we identified five ways in which transposition can supply promoters to transcriptionally silent genes. Besides highlighting the diversity and specific features of several TEs, the analyses performed in this study have provided novel and interesting information on (i the dynamics of the process of transposition (e.g. the unusually high frequency of transposition of TnPpa1 and (ii structural changes in DNA mediated by transposition (e.g. the generation of large deletions in the recipient molecule upon transposition of ISPve1 of the IS21 family. We also demonstrated the great potential of TEs and transposition in the generation of diverse phenotypes as well as in the natural amplification and dissemination of genetic information (of adaptative value by horizontal gene transfer, which is considered the driving force of

  11. Co-ordinate loss of protein kinase C and multidrug resistance gene expression in revertant MCF-7/Adr breast carcinoma cells.

    Science.gov (United States)

    Budworth, J; Gant, T W; Gescher, A

    1997-01-01

    The aim of this study was to investigate the link between protein kinase C (PKC) and multidrug resistance (mdr) phenotype. The expression of both was studied in doxorubicin-resistant MCF-7/Adr cells as they reverted to the wild-type phenotype when cultured in the absence of drug. The following parameters were measured in cells 4, 10, 15, 20 and 24 weeks after removal of doxorubicin; (1) sensitivity of the cells towards doxorubicin; (2) levels of P-glycoprotein (P-gp) and MDR1 mRNA; (3) levels and cellular localization of PKC isoenzyme proteins alpha, theta and epsilon; and (4) gene copy number of PKC-alpha and MDR1 genes. Cells lost their resistance gradually with time, so that by week 24 they had almost completely regained the drug sensitivity seen in wild-type MCF-7 cells. P-gp levels measured by Western blot mirrored the change in doxorubicin sensitivity. By week 20, P-gp had decreased to 18% of P-gp protein levels at the outset, and P-gp was not detectable at week 24. Similarly, MDR1 mRNA levels had disappeared by week 24. MCF-7/Adr cells expressed more PKCs-alpha and -theta than wild-type cells and possessed a different cellular localization of PKC-epsilon. The expression and distribution pattern of these PKCs did not change for up to 20 weeks, but reverted back to that seen in wild-type cells by week 24. MDR1 gene amplification remained unchanged until week 20, but then was lost precipitously between weeks 20 and 24. The PKC-alpha gene was not amplified in MCF-7/Adr cells. The results suggest that MCF-7/Adr cells lose MDR1 gene expression and PKC activity in a co-ordinate fashion, consistent with the existence of a mechanistic link between MDR1 and certain PKC isoenzymes.

  12. The role of reactive oxygen species in WP 631-induced death of human ovarian cancer cells: a comparison with the effect of doxorubicin.

    Science.gov (United States)

    Rogalska, Aneta; Gajek, Arkadiusz; Szwed, Marzena; Jóźwiak, Zofia; Marczak, Agnieszka

    2011-12-01

    In the present study, we investigated the anticancer activity of WP 631, a new anthracycline analog, in weakly doxorubicin-resistant SKOV-3 ovarian cancer cells. We studied the time-course of apoptotic and necrotic events: the production of reactive oxygen species (ROS) and changes in the mitochondrial membrane potential in human ovarian cancer cells exposed to WP 631 in the presence and absence of an antioxidant, N-acetylcysteine (NAC). The effect of WP 631 was compared with the activity of doxorubicin (DOX), the best known first-generation anthracycline. Cytotoxic activity was determined by the MTT assay. The morphological changes characteristic of apoptosis and necrosis in drug-treated cells were analyzed by double staining with Hoechst 33258 and propidium iodide (PI) using fluorescence microscopy. The production of reactive oxygen species and changes in mitochondrial membrane potential were studied using specific fluorescence probes: DCFH2-DA and JC-1, respectively. The experiments showed that WP 631 was three times more cytotoxic than DOX in the tested cell line. It was found that the new anthracycline analog induced mainly apoptosis and, marginally, necrosis. Apoptotic cell death was associated with morphological changes and a decrease in mitochondrial membrane potential. In comparison to DOX, the novel bisanthracycline induced a significantly higher level of ROS and a greater drop in the membrane potential. The results provide direct evidence that the novel anthracycline WP 631 is considerably more cytotoxic to human SKOV-3 ovarian cancer cells than doxorubicin. The drug can produce ROS, which are immediately involved in the induction of apoptotic cell death. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. BAG3 Overexpression and Cytoprotective Autophagy Mediate Apoptosis Resistance in Chemoresistant Breast Cancer Cells

    Directory of Open Access Journals (Sweden)

    Chandan Kanta Das

    2018-03-01

    Full Text Available Target-specific treatment modalities are currently not available for triple-negative breast cancer (TNBC, and acquired chemotherapy resistance is a primary obstacle for the treatment of these tumors. Here we employed derivatives of BT-549 and MDA-MB-468 TNBC cell lines that were adapted to grow in the presence of either 5-Fluorouracil, Doxorubicin or Docetaxel in an aim to identify molecular pathways involved in the adaptation to drug-induced cell killing. All six drug-adapted BT-549 and MDA-MB-468 cell lines displayed cross resistance to chemotherapy and decreased apoptosis sensitivity. Expression of the anti-apoptotic co-chaperone BAG3 was notably enhanced in two thirds (4/6 of the six resistant lines simultaneously with higher expression of HSP70 in comparison to parental controls. Doxorubicin-resistant BT-549 (BT-549rDOX20 and 5-Fluorouracil-resistant MDA-MB-468 (MDA-MB-468r5-FU2000 cells were chosen for further analysis with the autophagy inhibitor Bafilomycin A1 and lentiviral depletion of ATG5, indicating that enhanced cytoprotective autophagy partially contributes to increased drug resistance and cell survival. Stable lentiviral BAG3 depletion was associated with a robust down-regulation of Mcl-1, Bcl-2 and Bcl-xL, restoration of drug-induced apoptosis and reduced cell adhesion in these cells, and these death-sensitizing effects could be mimicked with the BAG3/Hsp70 interaction inhibitor YM-1 and by KRIBB11, a selective transcriptional inhibitor of HSF-1. Furthermore, BAG3 depletion was able to revert the EMT-like transcriptional changes observed in BT-549rDOX20 and MDA-MB-468r5-FU2000 cells. In summary, genetic and pharmacological interference with BAG3 is capable to resensitize TNBC cells to treatment, underscoring its relevance for cell death resistance and as a target to overcome therapy resistance of breast cancer.

  14. Integrated proteomic and N-glycoproteomic analyses of doxorubicin sensitive and resistant ovarian cancer cells reveal glycoprotein alteration in protein abundance and glycosylation

    Science.gov (United States)

    Hou, Junjie; Zhang, Chengqian; Xue, Peng; Wang, Jifeng; Chen, Xiulan; Guo, Xiaojing; Yang, Fuquan

    2017-01-01

    Ovarian cancer is one of the most common cancer among women in the world, and chemotherapy remains the principal treatment for patients. However, drug resistance is a major obstacle to the effective treatment of ovarian cancers and the underlying mechanism is not clear. An increased understanding of the mechanisms that underline the pathogenesis of drug resistance is therefore needed to develop novel therapeutics and diagnostic. Herein, we report the comparative analysis of the doxorubicin sensitive OVCAR8 cells and its doxorubicin-resistant variant NCI/ADR-RES cells using integrated global proteomics and N-glycoproteomics. A total of 1525 unique N-glycosite-containing peptides from 740 N-glycoproteins were identified and quantified, of which 253 N-glycosite-containing peptides showed significant change in the NCI/ADR-RES cells. Meanwhile, stable isotope labeling by amino acids in cell culture (SILAC) based comparative proteomic analysis of the two ovarian cancer cells led to the quantification of 5509 proteins. As about 50% of the identified N-glycoproteins are low-abundance membrane proteins, only 44% of quantified unique N-glycosite-containing peptides had corresponding protein expression ratios. The comparison and calibration of the N-glycoproteome versus the proteome classified 14 change patterns of N-glycosite-containing peptides, including 8 up-regulated N-glycosite-containing peptides with the increased glycosylation sites occupancy, 35 up-regulated N-glycosite-containing peptides with the unchanged glycosylation sites occupancy, 2 down-regulated N-glycosite-containing peptides with the decreased glycosylation sites occupancy, 46 down-regulated N-glycosite-containing peptides with the unchanged glycosylation sites occupancy. Integrated proteomic and N-glycoproteomic analyses provide new insights, which can help to unravel the relationship of N-glycosylation and multidrug resistance (MDR), understand the mechanism of MDR, and discover the new diagnostic and

  15. Intercellular transfer of P-glycoprotein from the drug resistant human bladder cancer cell line BIU-87 does not require cell-to-cell contact.

    Science.gov (United States)

    Zhou, Hui-liang; Zheng, Yong-jun; Cheng, Xiao-zhi; Lv, Yi-song; Gao, Rui; Mao, Hou-ping; Chen, Qin

    2013-09-01

    The efflux activity of transmembrane P-glycoprotein prevents various therapeutic drugs from reaching lethal concentrations in cancer cells, resulting in multidrug resistance. We investigated whether drug resistant bladder cancer cells could transfer functional P-glycoprotein to sensitive parental cells. Drug sensitive BIU-87 bladder cancer cells were co-cultured for 48 hours with BIU-87/ADM, a doxorubicin resistant derivative of the same cell line, in a Transwell® system that prevented cell-to-cell contact. The presence of P-glycoprotein in recipient cell membranes was established using fluorescein isothiocyanate, laser scanning confocal microscopy and Western blot. P-glycoprotein mRNA levels were compared between cell types. Rhodamine 123 efflux assay was done to confirm that P-glycoprotein was biologically active. The amount of P-glycoprotein protein in BIU-87 cells co-cultured with BIU-87/ADM was significantly higher than in BIU-87 cells (0.44 vs 0.25) and BIU-87/H33342 cells (0.44 vs 0.26, each p transfer. P-glycoprotein mRNA expression was significantly higher in BIU-87/ADM cells than in co-cultured BIU-87 cells (1.28 vs 0.30), BIU-87/H33342 (0.28) and BIU-87 cells (0.25, each p <0.001), ruling out a genetic mechanism. After 30 minutes of efflux, rhodamine 123 fluorescence intensity was significantly lower in BIU-87/ADM cells (5.55 vs 51.45, p = 0.004) and co-cultured BIU-87 cells than in BIU-87 cells (14.22 vs 51.45, p <0.001), indicating that P-glycoprotein was functional. Bladder cancer cells can acquire functional P-glycoprotein through a nongenetic mechanism that does not require direct cell contact. This mechanism is consistent with a microparticle mediated process. Copyright © 2013 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  16. Involvement of Cox-2 in the metastatic potential of chemotherapy-resistant breast cancer cells

    International Nuclear Information System (INIS)

    Kang, Ju-Hee; Song, Ki-Hoon; Jeong, Kyung-Chae; Kim, Sunshin; Choi, Changsun; Lee, Chang Hoon; Oh, Seung Hyun

    2011-01-01

    A major problem with the use of current chemotherapy regimens for several cancers, including breast cancer, is development of intrinsic or acquired drug resistance, which results in disease recurrence and metastasis. However, the mechanisms underlying this drug resistance are unknown. To study the molecular mechanisms underlying the invasive and metastatic activities of drug-resistant cancer cells, we generated a doxorubicin-resistant MCF-7 breast cancer cell line (MCF-7/DOX). We used MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assays, flow cytometry assays, DNA fragmentation assays, Western blot analysis, cell invasion assays, small interfering RNA (siRNA) transfection, reverse transcription-polymerase chain reaction, experimental lung metastasis models, and gelatin and fibrinogen/plasminogen zymography to study the molecular mechanism of metastatic activities in MCF-7/DOX cells. We found that MCF-7/DOX acquired invasive activities. In addition, Western blot analysis showed increased expression of epidermal growth factor receptor (EGFR) and Cox-2 in MCF-7/DOX cells. Inhibition of Cox-2, phosphoinositide 3-kinase (PI3K)/Akt, or mitogen-activated protein kinase (MAPK) pathways effectively inhibited the invasive activities of MCF-7/DOX cells. Gelatin and fibrinogen/plasminogen zymography analysis showed that the enzymatic activities of matrix metalloproteinase-2 (MMP-2), MMP-9, and urokinase-type plasminogen activator were markedly higher in MCF-7/DOX cells than in the MCF-7 cells. In vitro invasion assays and mouse models of lung metastasis demonstrated that MCF-7/DOX cells acquired invasive abilities. Using siRNAs and agonists specific for prostaglandin E (EP) receptors, we found that EP1 and EP3 played important roles in the invasiveness of MCF-7/DOX cells. We found that the invasive activity of MCF-7/DOX cells is mediated by Cox-2, which is induced by the EGFR-activated PI3K/Akt and MAPK pathways. In addition, EP1 and EP3 are important in

  17. Effect of verapamil on cellular uptake of Tc-99m MIBI and tetrofosmin on several cancer cells

    International Nuclear Information System (INIS)

    Kim, Dae Hyun; Yoo, Jung Ah; Bae, Jin Ho; Jeong, Shin Young; Suh, Myung Rang; Ahn, Byeong Cheol; Lee, Kyu Bo; Lee, Jae Tae

    2004-01-01

    Cellular uptake of 99 mTc-sestamibi (MIBI) and 99 mTc-tetrofosmin (TF) is low in cancer cells expressing multidrug resistance(MDR) by p-glycoprotein(Pgp) or multidrug related protein(MRP). Verapamil is known to increase cellular uptake of MIBI in MDR cancer cells, but is recently reported to have different effects on tracer uptake in certain cancer cells. This study was prepared to evaluate effects of verapamil on cellular uptake of MIBI and TF in several cancer cells. Cellular uptakes of Tc-99m MIBI and TF were measured in erythroleukemia K562 cell, breast cancer MCF7 cell, and human ovarian cancer SK-OV-3 cells, and data were compared with those of doxorubicin-resistant K562(Ad) cells. RT-PCR and Western blot analysis were used for the detection of mdr1 mRNA and Pgp expression, and to observe changes in isotypes of PKC enzyme. Effects of verapamil on MIBI and TF uptake were evaluated at different concentrations upto 200 μM at 1*10 6 cells/ m l at 37.deg.C. Radioactivity in supernatant and pellet was measured with gamma counter to calculate cellular uptake ratio. Toxicity of verapamil was measured with MTT assay. Cellular uptakes of MIBI and TF were increased by time in four cancer cells studied. Co-incubation with verapamil resulted in an increase in uptake of MIBI and TF in K562(Adr) cell at a concentration of 100 μM and the maximal increase at 50 μM was 10-times to baseline. In contrast, uptakes of MIBI and TF in K562, MCF7m SK-OV3 cells were decreased with verapamil treatment at a concentration over 1 μM. With a concentration of 200 μM verapamil, respectively. Cellular uptakes of MIBI and TF in MCF7 and SK-OV-3 cells were not changed with 10μM, but were also decreased with verapamil higher than 10μM, resulting 40% and 5% of baseline at 50 μM. MTT assay of four cells revealed that K562, MCF7, SK-OV3 were not damaged with verapamil at 200 μM. Although verapamil increases uptake of MIBI and TF in MDR cancer cells, cellular uptakes were further decreased

  18. BAG3 Overexpression and Cytoprotective Autophagy Mediate Apoptosis Resistance in Chemoresistant Breast Cancer Cells.

    Science.gov (United States)

    Das, Chandan Kanta; Linder, Benedikt; Bonn, Florian; Rothweiler, Florian; Dikic, Ivan; Michaelis, Martin; Cinatl, Jindrich; Mandal, Mahitosh; Kögel, Donat

    2018-03-01

    Target-specific treatment modalities are currently not available for triple-negative breast cancer (TNBC), and acquired chemotherapy resistance is a primary obstacle for the treatment of these tumors. Here we employed derivatives of BT-549 and MDA-MB-468 TNBC cell lines that were adapted to grow in the presence of either 5-Fluorouracil, Doxorubicin or Docetaxel in an aim to identify molecular pathways involved in the adaptation to drug-induced cell killing. All six drug-adapted BT-549 and MDA-MB-468 cell lines displayed cross resistance to chemotherapy and decreased apoptosis sensitivity. Expression of the anti-apoptotic co-chaperone BAG3 was notably enhanced in two thirds (4/6) of the six resistant lines simultaneously with higher expression of HSP70 in comparison to parental controls. Doxorubicin-resistant BT-549 (BT-549 r DOX 20 ) and 5-Fluorouracil-resistant MDA-MB-468 (MDA-MB-468 r 5-FU 2000 ) cells were chosen for further analysis with the autophagy inhibitor Bafilomycin A1 and lentiviral depletion of ATG5, indicating that enhanced cytoprotective autophagy partially contributes to increased drug resistance and cell survival. Stable lentiviral BAG3 depletion was associated with a robust down-regulation of Mcl-1, Bcl-2 and Bcl-xL, restoration of drug-induced apoptosis and reduced cell adhesion in these cells, and these death-sensitizing effects could be mimicked with the BAG3/Hsp70 interaction inhibitor YM-1 and by KRIBB11, a selective transcriptional inhibitor of HSF-1. Furthermore, BAG3 depletion was able to revert the EMT-like transcriptional changes observed in BT-549 r DOX 20 and MDA-MB-468 r 5-FU 2000 cells. In summary, genetic and pharmacological interference with BAG3 is capable to resensitize TNBC cells to treatment, underscoring its relevance for cell death resistance and as a target to overcome therapy resistance of breast cancer. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

  19. Down-regulation of human topoisomerase IIα expression correlates with relative amounts of specificity factors Sp1 and Sp3 bound at proximal and distal promoter regions

    Directory of Open Access Journals (Sweden)

    Isaacs Richard J

    2007-05-01

    Full Text Available Abstract Background Topoisomerase IIα has been shown to be down-regulated in doxorubicin-resistant cell lines. The specificity proteins Sp1 and Sp3 have been implicated in regulation of topoisomerase IIα transcription, although the mechanism by which they regulate expression is not fully understood. Sp1 has been shown to bind specifically to both proximal and distal GC elements of the human topoisomerase IIα promoter in vitro, while Sp3 binds only to the distal GC element unless additional flanking sequences are included. While Sp1 is thought to be an activator of human topoisomerase IIα, the functional significance of Sp3 binding is not known. Therefore, we sought to determine the functional relationship between Sp1 and Sp3 binding to the topoisomerase IIα promoter in vivo. We investigated endogenous levels of Sp1, Sp3 and topoisomerase IIα as well as binding of both Sp1 and Sp3 to the GC boxes of the topoisomerase IIα promoter in breast cancer cell lines in vivo after short term doxorubicin exposure. Results Functional effects of Sp1 and Sp3 were studied using transient cotransfection assays using a topoisomerase IIα promoter reporter construct. The in vivo interactions of Sp1 and Sp3 with the GC elements of the topoisomerase IIα promoter were studied in doxorubicin-treated breast cancer cell lines using chromatin immunoprecipitation assays. Relative amounts of endogenous proteins were measured using immunoblotting. In vivo DNA looping mediated by proteins bound at the GC1 and GC2 elements was studied using the chromatin conformation capture assay. Both Sp1 and Sp3 bound to the GC1 and GC2 regions. Sp1 and Sp3 were transcriptional activators and repressors respectively, with Sp3 repression being dominant over Sp1-mediated activation. The GC1 and GC2 elements are linked in vivo to form a loop, thus bringing distal regulatory elements and their cognate transcription factors into close proximity with the transcription start site