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Sample records for reverses doxorubicin resistance

  1. Reversal of doxorubicin resistance by guggulsterone of Commiphora mukul in vivo.

    Science.gov (United States)

    Xu, Hong-Bin; Shen, Zhao-Li; Fu, Jin; Xu, Lu-Zhong

    2014-09-25

    Our previous study has shown co-administration of guggulsterone resulted in significant increase in chemosensitivity of multidrug-resistant human breast cancer MCF-7/DOX cells to doxorubicin (DOX) in vitro. The present study was designed to investigate whether guggulsterone had the similar modulatory activities in vivo. MCF-7/DOX and MCF-7 xenograft mice models were established. At the end of the experiment (day 28), doxorubicin treatment alone did not significantly inhibit tumor growth in MCF-7/DOX xenograft, indicating that it retained doxorubicin resistance. Whereas, doxorubicin treatment alone significantly inhibited tumor growth in MCF-7 xenograft, suggesting that it maintained doxorubicin sensitivity. When doxorubicin and guggulsterone were co-administrated, their antitumor activities were augmented in MCF-7/DOX xenograft. However, combination therapy did not enhance the antitumor effects of doxorubicin in MCF-7 xenograft. The expression of proliferative cell nuclear antigens PCNA and Ki67 after doxorubicin treatment alone was not significantly different from that of vehicle group in MCF-7/DOX xenograft. On the contrary, doxorubicin treatment alone significantly reduced PCNA and Ki67 expression in MCF-7 xenograft. Combination therapy also significantly reduced PCNA and Ki67 expression in MCF-7/DOX xenograft, compared to doxorubicin treatment alone. However, combination therapy did not enhance the inhibitory effects of doxorubicin on PCNA and Ki67 expression in MCF-7 xenograft. Examining the apoptotic index by TUNEL assay showed similar results. Further studies demonstrated the inhibitory effects of guggulsterone on Bcl-2 and P-glycoprotein expression were the possible reason to increase chemosensitivity of MCF-7/DOX cells to doxorubicin in vivo. Examining body weight, hematological parameters, hepatic, cardiac and gastrointestinal tracts histopathology revealed that no significant signs of toxicity were related to guggulsterone. Guggulsterone might reverse

  2. Effect of Y6, an epigallocatechin gallate derivative, on reversing doxorubicin drug resistance in human hepatocellular carcinoma cells.

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    Wen, Yan; Zhao, Rui-Qiang; Zhang, Yun-Kai; Gupta, Pranav; Fu, Li-Xiang; Tang, An-Zhou; Liu, Bu-Ming; Chen, Zhe-Sheng; Yang, Dong-Hua; Liang, Gang

    2017-05-02

    Cancer cells can acquire resistance to a wide variety of diverse and unrelated drugs, this phenomenon is termed multidrug resistance (MDR). Multidrug resistance has been an obstacle to the success of cancer chemotherapy. The present study investigated the reversal effect of Y6, a new compound obtained by chemically modifying the structure of epigallocatechin-3-gallate (EGCG) extracted from green tea. Y6 was proven to be effective in inhibiting cell proliferation and reversing drug resistance in doxorubicin (DOX) resistant human hepatocellular carcinoma cells (BEL-7404/DOX). BEL-7404/DOX cells were treated with either doxorubicin combination regimen (doxorubicin plus Y6 or epigallocatechin-3-gallate or verapamil separately) or doxorubicin alone. The results showed that cell proliferation was inhibited and late cell apoptosis increased in the combination treatment group, especially in the group treated with doxorubicin plus Y6. Further analysis revealed that the expressions of hypoxia-inducible factor-1α and multidrug resistance 1/P-glycoprotein decreased at both messenger RNA and protein levels by treatments with combined drugs compared to doxorubicin alone. Our results indicated that Y6, as a drug resistance reversal agent, increased the sensitivity of drug resistant cells to doxorubicin. The mechanisms of actions of Y6 in reversal effect were associated with the decreased expression of hypoxia-inducible factor-1α and multidrug resistance 1/P-glycoprotein.

  3. Mesoporous silica nanoparticles loading doxorubicin reverse multidrug resistance: performance and mechanism

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    Shen, Jianan; He, Qianjun; Gao, Yu; Shi, Jianlin; Li, Yaping

    2011-10-01

    Multidrug resistance (MDR) is one of the major obstacles for successful chemotherapy in cancer. One of the effective approaches to overcome MDR is to use nanoparticle-mediated drug delivery to increase drug accumulation in drug resistant cancer cells. In this work, we first report that the performance and mechanism of an inorganic engineered delivery system based on mesoporous silica nanoparticles (MSNs) loading doxorubicin (DMNs) to overcome the MDR of MCF-7/ADR (a DOX-resistant and P-glycoprotein (P-gp) over-expression cancer cell line). The experimental results showed that DMNs could enhance the cellular uptake of doxorubicin (DOX) and increase the cell proliferation suppression effect of DOX against MCF-7/ADR cells. The IC50 of DMNs against MCF-7/ADR cells was 8-fold lower than that of free DOX. However, an improved effect of DOX in DMNs against MCF-7 cells (a DOX-sensitive cancer cell line) was not found. The increased cellular uptake and nuclear accumulation of DOX delivered by DMNs in MCF-7/ADR cells was confirmed by confocal laser scanning microscopy, and could result from the down-regulation of P-gp and bypassing the efflux action by MSNs themselves. The cellular uptake mechanism of DMNs indicated that the macropinocytosis was one of the pathways for the uptake of DMNs by MCF-7/ADR cells. The in vivo biodistribution showed that DMNs induced a higher accumulation of DOX in drug resistant tumors than free DOX. These results suggested that MSNs could be an effective delivery system to overcome multidrug resistance.

  4. Dasatinib reverses the multidrug resistance of breast cancer MCF-7 cells to doxorubicin by downregulating P-gp expression via inhibiting the activation of ERK signaling pathway

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    Chen, Ting; Wang, Changyuan; Liu, Qi; Meng, Qiang; Sun, Huijun; Huo, Xiaokui; Sun, Pengyuan; Peng, Jinyong; Liu, Zhihao; Yang, Xiaobo; Liu, Kexin

    2015-01-01

    Multidrug resistance (MDR) is one of the major obstacles to the efficiency of cancer chemotherapy, which often results from the overexpression of drug efflux transporters such as P-glycoprotein (P-gp). In the present study, we determined the effect of dasatinib which was approved for imatinib resistant chronic myelogenous leukemia (CML) and (Ph+) acute lymphoblastic leukemia (ALL) treatment on P-gp-mediated MDR. Our results showed that dasatinib significantly increased the sensitivity of P-gp-overexpressing MCF-7/Adr cells to doxorubicin in MTT assays; thus lead to an enhanced cytotoxicity of doxorubicin in MCF-7/Adr cells. Additionally, dasatinib increased the intracellular accumulation, inhibited the efflux of doxorubicin in MCF-7/Adr cells, and significantly enhanced doxorubicin-induced apoptosis in MCF-7/Adr cells. Further studies showed that dasatinib altered the expression levels of mRNA, protein levels of P-gp, and the phosphorylation of signal–regulated kinase (ERK) both in time-dependent (before 24 h) and dose-dependent manners at concentrations that produced MDR reversals. In conclusion, dasatinib reverses P-gp-mediated MDR by downregulating P-gp expression, which may be partly attributed to the inhibition of ERK pathway. Dasatinib may play an important role in circumventing MDR when combined with other conventional antineoplastic drugs. PMID:25482933

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

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    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.

  6. Salinomycin enhances doxorubicin-induced cytotoxicity in multidrug resistant MCF-7/MDR human breast cancer cells via decreased efflux of doxorubicin.

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    Kim, Kwang-Youn; Kim, Sang-Hun; Yu, Sun-Nyoung; Park, Suel-Ki; Choi, Hyeun-Deok; Yu, Hak-Sun; Ji, Jae-Hoon; Seo, Young-Kyo; Ahn, Soon-Cheol

    2015-08-01

    Salinomycin is a monocarboxylic polyether antibiotic, which is widely used as an anticoccidial agent. The anticancer property of salinomycin has been recognized and is based on its ability to induce apoptosis in human multidrug resistance (MDR). The present study investigated whether salinomycin reverses MDR towards chemotherapeutic agents in doxorubicin-resistant MCF-7/MDR human breast cancer cells. The results demonstrated that doxorubicin-mediated cytotoxicity was significantly enhanced by salinomycin in the MCF-7/MDR cells, and this occurred in a dose-dependent manner. This finding was consistent with subsequent observations made under a confocal microscope, in which the doxorubicin fluorescence signals of the salinomycin-treated cells were higher compared with the cells treated with doxorubicin alone. In addition, flow cytometric analysis revealed that salinomycin significantly increased the net cellular uptake and decreased the efflux of doxorubicin. The expression levels of MDR-1 and MRP-1 were not altered at either the mRNA or protein levels in the cells treated with salinomycin. These results indicated that salinomycin was mediated by its ability to increase the uptake and decrease the efflux of doxorubicin in MCF-7/MDR cells. Salinomycin reversed the resistance of doxorubicin, suggesting that chemotherapy in combination with salinomycin may benefit MDR cancer therapy.

  7. Chemomodulation of Doxorubicin Pharmacodynamics

    National Research Council Canada - National Science Library

    Sridhar, Rajagopalan

    2004-01-01

    .... We have found that in general, multidrug resistance reversing agents inhibit free radical mediated microsomal lipid peroxidation, but do not inhibit the conversion of doxorubicin to its semiquinone free radical...

  8. Artesunate induces ROS-mediated apoptosis in doxorubicin-resistant T leukemia cells.

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    Thomas Efferth

    Full Text Available BACKGROUND: A major obstacle for successful cancer treatment often is the development of drug resistance in cancer cells during chemotherapy. Therefore, there is an urgent need for novel drugs with improved efficacy against tumor cells and with less toxicity on normal cells. Artesunate (ART, a powerful anti-malarial herbal compound, has been shown to inhibit growth of various tumor cell lines in vitro and of xenografted Kaposi's sarcoma in mice in vivo. However, the molecular mechanisms by which ART exerts its cytotoxicity have not been elucidated. The ART-class of anti-malarial compounds is attractive due to their activity against multidrug-resistant Plasmodium falciparum and Plasmodium vivax strains. Another salient feature of these compounds is the lack of severe side effects in malaria patients. METHODOLOGY AND PRINCIPAL FINDINGS: In this study, we used T-cell leukemias as a model system to study the molecular mechanisms of ART-induced apoptosis. The most typical anticancer drugs are DNA intercalators such as Doxorubicin. To investigate drug sensitivity and resistance, we chose a Doxorubicin-resistant leukemia cell line and investigated the killing effect of ART on these cells. We show that ART induces apoptosis in leukemic T cells mainly through the mitochondrial pathway via generation of reactive oxygen species (ROS, a mechanism different from Doxorubicin. This is confirmed by the fact that the antioxidant N-Acetyle-Cysteine (NAC could completely block ROS generation and, consequently, inhibited ART-induced apoptosis. Therefore, ART can overcome the Doxorubicin-resistance and induce the Doxorubicin-resistant leukemia cells to undergo apoptosis. We also show that ART can synergize with Doxorubicin to enhance apoptotic cell death in leukemic T cells. This synergistic effect can be largely explained by the fact that ART and Doxorubicin use different killing mechanisms. CONCLUSIONS: Our studies raise the possibility to develop ART in

  9. Altered cell cycle response of drug-resistant lung carcinoma cells to doxorubicin.

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    O'Loughlin, C; Heenan, M; Coyle, S; Clynes, M

    2000-06-01

    The effect of doxorubicin treatment on cell cycle parameters in asynchronous populations of multidrug-resistant human lung carcinoma cell lines was investigated. A sensitive (DLKP-SQ) and three resistant (DLKP-SQ A250 10p#7, DLKP-A2B and DLKP-A5F) variants of a human lung carcinoma cell line DLKP were exposed to equitoxic concentrations of doxorubicin. The latter three were 8-fold, 30-fold and 300-fold resistant to doxorubicin, respectively. Irreversible G2/M arrest in sensitive (DLKP-SQ) cells was observed 24 h after initiation of doxorubicin treatment. In resistant variants, G2/M arrest occurred at 12-16 h with a subsequent bypass of the G2/M arrest to re-emerge and accumulate in G1. This transient G2/M arrest and subsequent progression into G1 indicated an inefficient checkpoint for monitoring DNA damage induced by doxorubicin treatment. Caffeine treatment could bypass the G2/M block in DLKP-SQ cells. Doxorubicin treatment did not alter cyclin B or cdc2 protein levels, the ability of cdc2 to form complexes with cyclin B or the levels of cyclin B bound to cdc2. The G2/M arrest seen in sensitive cells was associated with an increase in inhibitory phosphorylation of Tyr15 on cdc2. In contrast, tyrosine 15 phosphorylation did not change in resistant variants after drug treatment and a general increase in cdc2 kinase activity was seen. Cdc25C levels were not altered following drug treatment.

  10. Guiding TRAIL to cancer cells through Kv10.1 potassium channel overcomes resistance to doxorubicin.

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    Hartung, Franziska; Pardo, Luis A

    2016-10-01

    Resisting cell death is one of the hallmarks of cancer, and represents a common problem resulting in ineffective cancer therapy. To overcome resistance to apoptosis, we designed an antibody-based therapy strategy using Kv10.1 as a target. Kv10.1 is a voltage-gated potassium channel, which has been identified as a tumor marker several years ago. The agent consists of a Kv10.1-specific single-chain antibody fused to the soluble tumor necrosis factor-related apoptosis-inducing ligand (scFv62-TRAIL). We combined scFv62-TRAIL with different chemotherapeutic drugs, all of which failed to induce apoptosis when used alone. In the combination, we could overcome the resistance and selectively induce apoptosis. Among the drugs, doxorubicin showed the most promising effect. Additionally, we observed improved efficacy by pre-treating the cells with doxorubicin before scFv62-TRAIL application. Expression analysis of the TRAIL death receptors suggests a doxorubicin-induced increase in the abundance of receptors as the mechanism for sensitization. Furthermore, we confirmed the anti-tumor effect and efficacy of our combination strategy in vivo in SCID mice bearing subcutaneous tumors. In conclusion, we propose a novel strategy to overcome resistance to chemotherapy in cancer cells. Doxorubicin and scFv62-TRAIL reciprocally sensitize the cells to each other, specifically in Kv10.1-positive tumor cells.

  11. Trackable Mitochondria-Targeting Nanomicellar Loaded with Doxorubicin for Overcoming Drug Resistance.

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    Zhang, Ye; Zhang, Congjun; Chen, Jing; Liu, Li; Hu, Mengyue; Li, Jun; Bi, Hong

    2017-08-02

    Multidrug resistance (MDR) has been recognized as a major obstacle to successful chemotherapy for cancer in the clinic. In recent years, more and more nanoscaled drug delivery systems (DDS) are constructed to modulate drug efflux protein (P-gp) and deliver chemotherapeutic drugs for overcoming MDR. Among them, d-α-tocopheryl polyethylene glycol succinate (TPGS) has been widely used as a drug carrier due to its capability of inhibiting overexpression of P-gp and good amphiphilicity favorable for improving permeation and long-circulation property of DDS. In the present work, a novel kind of mitochondria-targeting nanomicelles-based DDS is developed to integrate chemotherapeutics delivery with fluorescence imaging functionalities on a comprehensive nanoplatform. The mitochondria-targeting nanomicelles are prepared by self-assembly of triphenylphosphine (TPP)-modified TPGS and fluorescent carbon quantum dots (CQDs) in an n-hexane/H2O mixed solution, named CQDs-TPGS-TPP. Notably, although the drug loading content of doxorubicin (DOX) in the as-prepared nanomicelles is as low as 3.4%, the calculated resistant index (RI) is greatly decreased from 66.23 of free DOX to 7.16 of DOX-loaded nanomicelles while treating both parental MCF-7 cells and drug-resistant MCF-7/ADR cells. Compared with free DOX, the penetration efficiency of DOX-loaded nanomicelles in three-dimensional multicellular spheroids (MCs) of MCF-7/ADR is obviously increased. Moreover, the released DOX from the nanomicelles can cause much more damage to cells of drug-resistant MCs. These results demonstrate that our constructed mitochondria-targeting nanomicelles-based DDS have potential application in overcoming MDR of cancer cells as well as their MCs that mimic in vivo tumor tissues. The MDR-reversal mechanism of the DOX-loaded CQDs-TPGS-TPP nanomicelles is also discussed.

  12. Sinomenine Sensitizes Multidrug-Resistant Colon Cancer Cells (Caco-2) to Doxorubicin by Downregulation of MDR-1 Expression

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    Liu, Zhen; Duan, Zhi-Jun; Chang, Jiu-Yang; Zhang, Zhi-feng; Chu, Rui; Li, Yu-Ling; Dai, Ke-Hang; Mo, Guang-quan; Chang, Qing-Yong

    2014-01-01

    Chemoresistance in multidrug-resistant (MDR) cells over expressing P-glycoprotein (P-gp) encoded by the MDR1 gene, is a major obstacle to successful chemotherapy for colorectal cancer. Previous studies have indicated that sinomenine can enhance the absorption of various P-gp substrates. In the present study, we investigated the effect of sinomenine on the chemoresistance in colon cancer cells and explored the underlying mechanism. We developed multidrug-resistant Caco-2 (MDR-Caco-2) cells by exposure of Caco-2 cells to increasing concentrations of doxorubicin. We identified overexpression of COX-2 and MDR-1 genes as well as activation of the NF-κB signal pathway in MDR-Caco-2 cells. Importantly, we found that sinomenine enhances the sensitivity of MDR-Caco-2 cells towards doxorubicin by downregulating MDR-1 and COX-2 expression through inhibition of the NF-κB signaling pathway. These findings provide a new potential strategy for the reversal of P-gp-mediated anticancer drug resistance. PMID:24901713

  13. CG5/Dx human breast cancer cell line: characterization of a new doxorubicin-resistant variant.

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    Gibelli, N; Zibera, C; Asti, A; Maestri, L; Bacchella, L; Pedrazzoli, P; Calligaro, A; Robustelli della Cuna, G

    1996-01-01

    By continuous exposure of CG5 human breast cancer cell line to increasing doxorubicin (Dx) concentrations, a multidrug-resistant (MDR) subline (CG5/Dx) was obtained. The resistant variant showed P-glycoprotein (P-gp) expression and a lower intracellular doxorubicin level than the parental cells. CG5/Dx cells were 19.4 fold more resistant to Dx than CG5 cells and showed a cross-resistance to some structurally related and unrelated compounds. Differences in kinetics, biological and ultrastructural features between the two cell lines were investigated. The CG5/Dx cells grew more slowly, produced higher CEA levels and showed a reduced progesterone receptor (PgR) content than the parental cells. Ultrastructural studies revealed differences involving, polyribosomes, rough endoplasmic reticulum, [mitochondria] and cytoskeleton.

  14. Nanomicelles loaded with doxorubicin and curcumin for alleviating multidrug resistance in lung cancer

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    Gu, Yue; Li, Jing; Li, Yang; Song, Lei; Li, Dan; Peng, Liping; Wan, Ying; Hua, Shucheng

    2016-01-01

    Purpose A new type of polymeric micelle (PM) was assembled using a polyethylene glycol (PEG)-linked (PEGylated) amphiphilic copolymer and d-tocopheryl PEG1000 succinate (TPGS1000). The micelles were used to deliver doxorubicin (DOX) and curcumin (CUR) for alleviating multidrug resistance (MDR) in lung cancer cells while enhancing the therapeutic efficacy of DOX. Methods Micelles loaded with DOX and CUR were assembled using a film-forming technique. Micelles were used to treat A549/Adr cells to find out whether micelles had the ability to reverse the MDR of A549/Adr cells. Some investigations were conducted using tumor-bearing mice to assess whether these micelles had enhanced antitumor efficacy as compared to DOX alone or the combination of DOX and CUR. Results Some micelles (DOX + CUR)–PMs had a small average size of about 17 nm and showed definite ability to deliver both DOX and CUR into DOX-resistant A549/Adr cells. The PMs had high cytotoxicity toward A549/Adr cells when the applied equivalent DOX dose was 1 µg/mL or higher. The cellular uptake of (DOX + CUR)–PMs into A549/Adr cells was found to be associated with an energy-dependent, caveolae-mediated, and clathrin-independent mechanism. (DOX + CUR)–PMs helped to prolong the circulation of DOX or CUR as compared to the individual administration of DOX or CUR, and they exhibited high inhibiting efficiency against the growth of tumors and were able to reduce the side effects of DOX. Conclusion TPGS1000 and CUR could synergistically reverse DOX-resistance of A549/Adr cells. In vivo examinations confirmed that the micelles had the capability to increase the plasma concentration of DOX or CUR, as well as to prolong their respective blood circulation. These micelles were able to significantly inhibit tumor growth in Lewis lung carcinoma tumor-bearing mice while reducing the side effects of DOX. The micelles showed potential in the treatment of lung cancer. PMID:27843316

  15. Hesperidin as a preventive resistance agent in MCF–7 breast cancer cells line resistance to doxorubicin

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    Rifki Febriansah

    2014-03-01

    Conclusions: Hesperidin has cytotoxic effect on MCF-7/Dox cells with IC50 of 11 μmol/L. Hesperidin did not increased the apoptotic induction combined with doxorubicin. Co-chemotherapy application of doxorubicin and hesperidin on MCF-7/Dox cells showed synergism effect through inhibition of Pgp expression.

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

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    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.

  17. 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.

  18. Bypassing multidrug resistant ovarian cancer using ultrasound responsive doxorubicin/curcumin co-deliver alginate nanodroplets.

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    Baghbani, Fatemeh; Moztarzadeh, Fathollah

    2017-05-01

    Ultrasound-responsive perfluorocarbon nanoemulsions are a class of new multifunctional smart nanocarriers which combine diagnostic properties with therapeutic properties and release their drug payload in a controlled manner in response to ultrasound. Therefore, combination therapy using chemotherapeutic and chemosensitizing agents co-entrapped in these nanocarriers seems beneficial for cancer treatment. In the present study, multifunctional smart alginate/perfluorohexane nanodroplets were developed for co-delivery of doxorubicin and curcumin (a strong chemosensitizer). The nanodroplets with the average particle size of 55.1nm were synthesized via nanoemulsion process. The entrapment efficiency of doxorubicin was 92.3%. To improve curcumin entrapment into the alginate shell, Span 60 was added to the formulation as a co-surfactant and finally curcumin entrapment of about 40% was achieved. Ultrasound-mediated drug release kinetic was evaluated at two different frequencies of 28kHz (low frequency) and 1MHz (high frequency). Low frequency ultrasound resulted in higher triggered drug release from nanodroplets. The nanodroplets showed strong ultrasound contrast via droplet to bubble transition as confirmed via B-mode ultrasound imaging. Enhanced cytotoxicity in adriamycin-resistant A2780 ovarian cancer cells was observed for Dox-Cur-NDs compared to Dox-NDs because of the synergistic effects of doxorubicin and curcumin. However, ultrasound irradiation significantly increased the cytotoxicity of Dox-Cur-NDs. Finally, in vivo ovarian cancer treatment using Dox/Cur-NDs combined with ultrasound irradiation resulted in efficient tumor regression. According to the present study, nanotherapy of multidrug resistant human ovarian cancer using ultrasound responsive doxorubicin/curcumin co-loaded alginate-shelled nanodroplets combined with ultrasound irradiation could be a promising modality for the future of cancer treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Quantitative analysis of histone H3 and H4 post-translational modifications in doxorubicin-resistant leukemia cells.

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    Liu, Tao; Guo, Qingcheng; Guo, Huaizu; Hou, Sheng; Li, Jing; Wang, Hao

    2016-04-01

    The epigenetic remodeling of chromatin through histone modifications has been widely implicated in drug resistance of cancer cells. However, whether epigenetic mechanisms contribute specifically to doxorubicin resistance in leukemia has not been carefully examined. Using a stable and sensitive workflow based on LC-MS, we quantitatively compared the extents of methylation and acetylation of histone H3 and H4 in acute leukemia cell line HL60 and its doxorubicin-resistant derivative, HL60/ADR, as well as the chronic leukemia cell line K562 and its doxorubicin-resistant derivative, K562/ADR. We found that increased levels of H3K9 methylation, H3K14, H3K18 and H3K23 acetylation, and potentially H4K20 methylation, are associated with drug resistance in both cells. Our results demonstrated that the doxorubicin-resistant acute and chronic leukemia cell lines may share a common epigenetic mechanism that involves a combination of transcriptional activation and silencing. Copyright © 2015 John Wiley & Sons, Ltd.

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

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    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.

  1. Lipid raft modulation by Rp1 reverses multidrug resistance via inactivating MDR-1 and Src inhibition.

    Science.gov (United States)

    Yun, Un-Jung; Lee, Ji-Hye; Koo, Kyung Hee; Ye, Sang-Kyu; Kim, Soo-Youl; Lee, Chang-Hun; Kim, Yong-Nyun

    2013-05-15

    Multidrug resistance (MDR) is a major obstacle to effective cancer therapy. The membrane transporter MDR-1 (P-gp, ABCB1), a member of the ATP-binding cassette (ABC) transporter family, effluxes anti-cancer drugs from cancer cells. Increased activity of MDR-1 is known to be the main mechanism for multidrug resistance. MDR-1 is known to be localized in the cholesterol- and sphingolipid-enriched plasma membrane microdomains, known as lipid rafts. Disruption of lipid rafts by cholesterol depletion alters lipid raft functions, indicating that cholesterol is critical for raft function. Because ginsenosides are structurally similar to cholesterol, in this study, we investigated the effect of Rp1, a novel ginsenoside derivative, on drug resistance using drug-sensitive OVCAR-8 and drug-resistant NCI/ADR-RES and DXR cells. Rp1 treatment resulted in an accumulation of doxorubicin or rhodamine 123 by decreasing MDR-1 activity in doxorubicin-resistant cells. Rp1 synergistically induced cell death with actinomycin D in DXR cells. Rp1 appeared to redistribute lipid rafts and MDR-1 protein. Moreover, Rp1 reversed resistance to actinomycin D by decreasing MDR-1 protein levels and Src phosphorylation with modulation of lipid rafts. Addition of cholesterol attenuated Rp1-induced raft aggregation and MDR-1 redistribution. Rp1 and actinomycin D reduced Src activity, and overexpression of active Src decreased the synergistic effect of Rp1 with actinomycin D. Rp1-induced drug sensitization was also observed with several anti-cancer drugs, including doxorubicin. These data suggest that lipid raft-modulating agents can be used to inhibit MDR-1 activity and thus overcome drug resistance. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. 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.

  3. 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.

  4. Multidrug evolutionary strategies to reverse antibiotic resistance

    Science.gov (United States)

    Baym, Michael; Stone, Laura K.; Kishony, Roy

    2017-01-01

    Antibiotic treatment has two conflicting effects: the desired, immediate effect of inhibiting bacterial growth and the undesired, long-term effect of promoting the evolution of resistance. Although these contrasting outcomes seem inextricably linked, recent work has revealed several ways by which antibiotics can be combined to inhibit bacterial growth while, counterintuitively, selecting against resistant mutants. Decoupling treatment efficacy from the risk of resistance can be achieved by exploiting specific interactions between drugs, and the ways in which resistance mutations to a given drug can modulate these interactions or increase the sensitivity of the bacteria to other compounds. Although their practical application requires much further development and validation, and relies on advances in genomic diagnostics, these discoveries suggest novel paradigms that may restrict or even reverse the evolution of resistance. PMID:26722002

  5. Phase II study of the combination of pegylated liposomal doxorubicin and topotecan in platinum-resistant ovarian cancer.

    Science.gov (United States)

    Verhaar-Langereis, M; Karakus, A; van Eijkeren, M; Voest, E; Witteveen, E

    2006-01-01

    The combination of liposomal doxorubicin and topotecan was evaluated in a phase II study in patients with platinum-resistant ovarian cancer. Twenty-seven patients received liposomal doxorubicin (30 mg/m(2)) infused at day 1, followed by topotecan (1 mg/m(2)) infusion daily for 5 days. Cycles were repeated every 21 days. This combination regimen showed an overall response rate of 28%. Median time to progression was 30 weeks, with a median overall survival of 40 weeks. Grade 3/4 neutropenia was shown in 70% of patients and grade 3/4 thrombopenia in 41% of patients. Neutropenic fever was reported in 11% of patients. After reviewing the first 12 patients, the internal review board decided to administer topotecan at a dose of 0.75 mg/m(2) and liposomal doxorubicin at 40 mg/m(2) for the remainder of the study. However, this adjustment did not lead to reduction in bone marrow toxicity nor to an improvement in dose intensity. Palmar-plantar erythrodysesthesia and mucositis were more reported in the second cohort but usually mild. The combination of liposomal doxorubicin and topotecan demonstrates favorable response data in platinum-resistant ovarian cancer. However, substantial bone marrow toxicity limits further clinical use.

  6. High-definition DNA methylation profiles from breast and ovarian carcinoma cell lines with differing doxorubicin resistance.

    Directory of Open Access Journals (Sweden)

    Michael Boettcher

    Full Text Available Acquired drug resistance represents a frequent obstacle which hampers efficient chemotherapy of cancers. The contribution of aberrant DNA methylation to the development of drug resistant tumor cells has gained increasing attention over the past decades. Hence, the objective of the presented study was to characterize DNA methylation changes which arise from treatment of tumor cells with the chemotherapeutic drug doxorubicin. DNA methylation levels from CpG islands (CGIs linked to twenty-eight genes, whose expression levels had previously been shown to contribute to resistance against DNA double strand break inducing drugs or tumor progression in different cancer types were analyzed. High-definition DNA methylation profiles which consisted of methylation levels from 800 CpG sites mapping to CGIs around the transcription start sites of the selected genes were determined. In order to investigate the influence of CGI methylation on the expression of associated genes, their mRNA levels were investigated via qRT-PCR. It was shown that the employed method is suitable for providing highly accurate methylation profiles, comparable to those obtained via clone sequencing, the gold standard for high-definition DNA methylation studies. In breast carcinoma cells with acquired resistance against the double strand break inducing drug doxorubicin, changes in methylation of specific cytosines from CGIs linked to thirteen genes were detected. Moreover, similarities between methylation profiles obtained from breast and ovarian carcinoma cell lines with acquired doxorubicin resistance were found. The expression levels of a subset of analyzed genes were shown to be linked to the methylation levels of the analyzed CGIs. Our results provide detailed DNA methylation information from two separate model systems for acquired doxorubicin resistance and suggest the occurrence of similar methylation changes in both systems upon exposure to the drug.

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

    Directory of Open Access Journals (Sweden)

    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.

  8. Liposomal nitrooxy-doxorubicin: one step over caelyx in drug-resistant human cancer cells.

    Science.gov (United States)

    Pedrini, Isabella; Gazzano, Elena; Chegaev, Konstantin; Rolando, Barbara; Marengo, Alessandro; Kopecka, Joanna; Fruttero, Roberta; Ghigo, Dario; Arpicco, Silvia; Riganti, Chiara

    2014-09-02

    In this work we prepared and characterized two liposomal formulations of a semisynthetic nitric oxide (NO)-releasing doxorubicin (Dox), called nitrooxy-Dox (NitDox), which we previously demonstrated to be cytotoxic in Dox-resistant human colon cancer cells. Liposomes with 38.2% (Lip A) and 19.1% (Lip B) cholesterol were synthesized: both formulations had similar size and zeta potential values and caused the same intracellular distribution of free NitDox, but Lip B accumulated and released NitDox more efficiently. In Dox-resistant human colon cancer cells, Lip A and Lip B exhibited a more favorable kinetics of drug uptake and NO release, and a stronger cytotoxicity than Dox and free NitDox. While Caelyx, one of the liposomal Dox formulations approved for breast and ovary tumors treatment, was ineffective in Dox-resistant breast/ovary cancer cells, Lip B, and to a lesser extent Lip A, still exerted a significant cytotoxicity in these cells. This event was accompanied in parallel by a higher release of NO, which caused nitration of P-glycoprotein (Pgp) and multidrug resistance related protein 1 (MRP1), two transporters involved in Dox efflux, and impaired their pump activity. By doing so, the efflux kinetics of Dox after treatment with Lip B was markedly slowed down and the intracellular accumulation of Dox was increased in breast and ovary drug-resistant cells. We propose these liposomal formulations of NitDox as new tools with a specific indication for tumors overexpressing Pgp and MRP1.

  9. Reversal of multidrug resistance by surfactants.

    Science.gov (United States)

    Woodcock, D. M.; Linsenmeyer, M. E.; Chojnowski, G.; Kriegler, A. B.; Nink, V.; Webster, L. K.; Sawyer, W. H.

    1992-01-01

    Cremophor EL, a pharmacologically inactive solubilising agent, has been shown to reverse multidrug resistance (MDR). Using flow cytometric evaluation of equilibrium intracellular levels of daunorubicin (DNR), we found that eight other surface active agents will also reverse MDR. All the active detergents contain polyethoxylated moieties but have no similarities in their hydrophobic components. The properties of three polyethoxylated surfactants that showed the lowest toxicities, Cremophor, Tween 80 and Solutol HS15, were examined in more detail. The concentrations of Tween 80 and Solutol required to reverse DNR exclusion were 10-fold lower than for Cremophor. However while concentrations greater than or equal to 1:10(2) of the former two surfactants resulted in breakdown of cells, even 1:10 of Cremophor did not lyse cells. Studies of the effects of Cremophor on the uptake and efflux of DNR in normal and MDR cell types showed that Cremophor increases intracellular DNR primarily by locking the rapid efflux from the cells. This blockage of drug efflux may be mediated by a substantial alteration in the fluidity of cell membranes induced by Cremophor, as shown by decreased fluorescence anisotropy of a membrane probe. Consistent with these data, coinjection of adriamycin plus Cremophor into mice carrying a multidrug resistant P388 transplantable tumour significantly increased the survival time of the mice compared with adriamycin treatment alone. PMID:1637678

  10. Drimane-type Sesquiterpene Coumarins from Ferula gummosa Fruits Enhance Doxorubicin Uptake in Doxorubicin-resistant Human Breast Cancer Cell Line

    Directory of Open Access Journals (Sweden)

    Mehrdad Iranshahi

    2014-04-01

    Full Text Available Multidrug resistance (MDR is the main cause of failure in the chemotherapy of cancer patients. The present study aimed to evaluate the effects of sesquiterpene coumarins of Ferula gummosa fruits on P-glycoprotein (P-gp–mediated MDR. Drimane-type sesquiterpene coumarins from the fruits of F. gummosa were extracted with dichloromethane and subjected to column chromatography. The effects of the isolated compounds on P-gp–mediated MDR were evaluated in the breast cancer cell line MCF-7 which shows high resistance to doxoribicin (MCF-7/Dox. Phytochemical investigation of dichloromethane extract of F. gummosa fruits resulted in three sesquiterpene coumarins including conferone (1, mogoltacin (2, and feselol (3. The structures of these compounds were confirmed by 1D and 2D Nuclear Magnetic Resonance (NMR spectroscopy. Exposure of cells to conferone, mogoltacin, feselol, and verapamil (positive control enhanced doxorubicin uptake by MCF-7/Dox cells. This effect was dose dependent, but varied with the structure of the chemical. At 25 μM, all the tested sesquiterpene coumarins restored at least 50% of the reference uptake (uptake by sensitive cells; but at 10 μM, their potency varied where conferone showed the highest potency and feselol showed the lowest potency. Conferone, mogoltacin, and feselol from F. gummosa suppress P-gp–mediated drug efflux in highly resistant human breast cancer cells.

  11. Panitumumab and Pegylated Liposomal Doxorubicin in Platinum-Resistant Epithelial Ovarian Cancer With KRAS Wild-Type

    DEFF Research Database (Denmark)

    Steffensen, Karina Dahl; Waldstrøm, Marianne; Pallisgård, Niels

    2013-01-01

    cancer patients treated with pegylated liposomal doxorubicin (PLD) supplemented with panitumumab. PATIENTS AND METHODS: Major eligibility criteria were relapsed ovarian/fallopian/peritoneal cancer patients with platinum-resistant disease, measurable disease by GCIG CA125 criteria and KRAS wild......OBJECTIVE: The increasing number of negative trials for ovarian cancer treatment has prompted an evaluation of new biologic agents, which in combination with chemotherapy may improve survival. The aim of this study was to investigate the response rate in platinum-resistant, KRAS wild-type ovarian...

  12. Balaglitazone reverses P-glycoprotein-mediated multidrug resistance via upregulation of PTEN in a PPARγ-dependent manner in leukemia cells.

    Science.gov (United States)

    Yousefi, Bahman; Azimi, Ako; Majidinia, Maryam; Shafiei-Irannejad, Vahid; Badalzadeh, Reza; Baradaran, Behzad; Zarghami, Nosratollah; Samadi, Nasser

    2017-10-01

    Multidrug resistance in tumor cells is still a big challenge in cancer treatment. Therefore, identification ofsafe and effective multidrug resistance-reversing compounds with minimal side effects is an important approach in cancer treatment. Here, we investigated the role and potential mechanisms of peroxisome proliferator-activated receptor γ in doxorubicin-resistant human myelogenous leukemia (K562/DOX) cells. The effect of doxorubicin on cell viability following treatment with balaglitazone, a peroxisome proliferator-activated receptor γ agonist, was evaluated using trypan blue and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays. Rhodamine123 assay was used to determine the activity of two common drug efflux membrane transporters P-glycoprotein and multidrug resistance protein-1. P-glycoprotein, multidrug resistance protein-1, and phosphatase and tensin homolog deleted on chromosome 10 messenger RNA/protein expression levels were measured by quantitative reverse transcription polymerase chain reaction and western blot analyses. Annexin V/fluorescein isothiocyanate assay was also employed to investigate apoptosis. We showed that balaglitazone considerably enhanced the cytotoxicity of doxorubicin. Balaglitazone also significantly downregulated P-glycoprotein expression and activity in K562/DOX cells and reduced multidrug resistance through elevation of intracellular doxorubicin in cells. Furthermore, upon balaglitazone treatment, phosphatase and tensin homolog deleted on chromosome 10 expression could be restored in K562/DOX cells in a peroxisome proliferator-activated receptor γ-dependent manner. We concluded that peroxisome proliferator-activated receptor γ agonist, balaglitazone, could reverse multidrug resistance by inducing phosphatase and tensin homolog deleted on chromosome 10 and peroxisome proliferator-activated receptor/ phosphatase and tensin homolog deleted on chromosome 10 signaling pathway. These findings suggest that

  13. Doxorubicin-loaded, charge reversible, folate modified HPMA copolymer conjugates for active cancer cell targeting.

    Science.gov (United States)

    Li, Lian; Yang, Qingqing; Zhou, Zhou; Zhong, Jiaju; Huang, Yuan

    2014-06-01

    Although folate exhibits many advantages over other targeting ligands, it has one major defect: poor water solubility. Once it was conjugated to hydrophilic drug carrier such as N-(2-hydroxypropyl) methacrylamide (HPMA) copolymer, the hydrophobic folate may be buried inside the random polymer coil and not exposed to be accessible to its receptor on the cell surface, thus losing its active targeting ability. To address this folate dilemma, the positive charge was introduced in the present study. The obtained cationic folate-functionalized HPMA copolymers exhibited a synergistic enhancing effect on cellular uptake by folate receptor (FR) positive Hela cells via electrostatic absorptive endocytosis and folate receptor-mediated endocytosis, with the involvement of multiple internalization pathways including clathrin-mediated endocytosis, caveolae-mediated endocytosis, macropinocytosis and energy-dependent endocytosis. As demonstrated in binding efficiency study, the FR antibody bound to 71.2% of tested cells in the competition with neutral folate modified HPMA copolymers, while the FR antibody-bounded cells decreased to only 34.0% in competition with cationic folate modified HPMA copolymers, indicating that the positively charge could probably amplify the binding efficiency of folate to its receptor due to close proximity of the conjugates to the cell surface by the electronic adhesion. In addition, the cell uptake study on FR negative A549 cells also confirmed the specific role of folate as targeting ligand. Then, to avoid non-specific binding by positive charge in the circulation, the charge shielding/deshielding approach was further employed. With selective hydrolysis of the charge shielding groups 2,3-dimethylmaleic anhydride (DMA) at tumor extracellular pH 6.8, the conjugates underwent a quick charge-reversible process with more than 80% DMA cleavage within 2 h and endocytosed into the endo/lysosomes much more rapidly than at physiological pH 7.4. And then the

  14. Troglitazone reverses the multiple drug resistance phenotype in cancer cells

    Directory of Open Access Journals (Sweden)

    Gerald F Davies

    2009-03-01

    Full Text Available Gerald F Davies1, Bernhard HJ Juurlink2, Troy AA Harkness11Department of Anatomy and Cell Biology, College of Medicine, University of Saskatchewan, Saskatoon, Canada; 2College of Medicine, Alfaisal University, Riyadh, Kingdom of Saudi ArabiaAbstract: A major problem in treating cancer is the development of drug resistance. We previously demonstrated doxorubicin (DOX resistance in K562 human leukemia cells that was associated with upregulation of glyoxalase 1 (GLO-1 and histone H3 expression. The thiazolidinedione troglitazone (TRG downregulated GLO-1 expression and further upregulated histone H3 expression and post-translational modifications in these cells, leading to a regained sensitivity to DOX. Given the pleiotropic effects of epigenetic changes in cancer development, we hypothesized that TRG may downregulate the multiple drug resistance (MDR phenotype in a variety of cancer cells. To test this, MCF7 human breast cancer cells and K562 cells were cultured in the presence of low-dose DOX to establish DOX-resistant cell lines (K562/DOX and MCF7/DOX. The MDR phenotype was confirmed by Western blot analysis of the 170 kDa P-glycoprotein (Pgp drug efflux pump multiple drug resistance protein 1 (MDR-1, and the breast cancer resistance protein (BCRP. TRG markedly decreased expression of both MDR-1 and BCRP in these cells, resulting in sensitivity to DOX. Silencing of MDR-1 expression also sensitized MCF7/DOX cells to DOX. Use of the specific and irreversible peroxisome proliferator-activated receptor gamma (PPARγ inhibitor GW9662 in the nanomolar range not only demonstrated that the action of TRG on MCF/DOX was PPARγ-independent, but indicated that PPARγ may play a role in the MDR phenotype, which is antagonized by TRG. We conclude that TRG is potentially a useful adjunct therapy in chemoresistant cancers. Keywords: chemotherapy, doxorubicin, breast cancer resistance protein-1, multiple drug resistance, multiple drug resistance protein 1

  15. Preparation of multilocation reduction-sensitive core crosslinked folate-PEG-coated micelles for rapid release of doxorubicin and tariquidar to overcome drug resistance

    Science.gov (United States)

    Yi, Xiaoqing; Zhao, Dan; Zhang, Quan; Xu, Jiaqi; Yuan, Gongdao; Zhuo, Renxi; Li, Feng

    2017-02-01

    Herein, we prepared folate-targeting core crosslinked polymeric micelles (CCL/FA) containing multiple disulfide bonds located at the interface and core of the micelles to co-deliver doxorubicin (DOX) and the P-glycoprotein (P-gp) inhibitor tariquidar (TQR) for reversing drug resistance. The stability and redox-responsive behavior of the CCL/FA micelles was evaluated through the changes in morphology, molecular weight and hydrodynamic size. On the one hand, the micelles possessed good stability, which led to the suppression of drug release from the CCL micelles in the physiological environment. On the other hand, under reductive conditions, the CCL micelles collapsed rapidly and accelerated drug release markedly. In vitro cytotoxicity measurements, combined with confocal laser scanning microscopy (CLSM) and flow cytometry, confirmed that the dual-drug-loaded micelles exhibited obviously higher cytotoxicity to MCF-7/ADR-resistant cells than free DOX · HCl, single-drug loaded CCL micelles and nontargeted CCL micelles. The results imply that co-delivering DOX and TQR by CCL/FA micelles may be a promising way of overcoming multidrug resistance in tumor treatments.

  16. A critical dose of doxorubicin is required to alter the gene expression profiles in MCF-7 cells acquiring multidrug resistance.

    Directory of Open Access Journals (Sweden)

    Shang-Hsun Tsou

    Full Text Available Cellular mechanisms of multidrug resistance (MDR are related to ABC transporters, apoptosis, antioxidation, drug metabolism, DNA repair and cell proliferation. It remains unclear whether the process of resistance development is programmable. We aimed to study gene expression profiling circumstances in MCF-7 during MDR development. Eleven MCF-7 sublines with incremental doxorubicin resistance were established as a valued tool to study resistance progression. MDR marker P-gp was overexpressed only in cells termed MCF-7/ADR-1024 under the selection dose approaching 1024 nM. MCF-7/ADR-1024 and authentic MCF-7/ADR shared common features in cell morphology and DNA ploidy status. MCF-7/ADR-1024 and authentic MCF-7/ADR down regulated repair genes BRCA1/2 and wild type p53, apoptosis-related gene Bcl-2 and epithelial-mesenchymal transition (EMT epithelial marker gene E-cadherin. While detoxifying enzymes glutathione-S transferase-π and protein kinase C-α were up-regulated. The genes involving in EMT mesenchymal formation were also overexpressed, including N-cadherin, vimentin and the E-cadherin transcription reppressors Slug, Twist and ZEB1/2. PI3K/AKT inhibitor wortmannin suppressed expression of Slug, Twist and mdr1. Mutant p53 with a deletion at codons 127-133 markedly appeared in MCF-7/ADR-1024 and authentic MCF-7/ADR as well. In addition, MCF-7/ADR-1024 cells exerted CSC-like cell surface marker CD44 high/CD24 low and form mammospheres. Overall, results suggest that resistance marker P-gp arises owing to turn on/off or mutation of the genes involved in DNA repair, apoptosis, detoxifying enzymes, EMT and ABC transporters at a turning point (1.024 μM doxorubicin challenge. Behind this point, no obvious alterations were found in most tested genes. Selection for CSC-like cells under this dose may importantly attribute to propagation of the population presenting invasive properties and drug resistance. We thereby suggest two models in the induction of

  17. Doxorubicin potentiates TRAIL cytotoxicity and apoptosis and can overcome TRAIL-resistance in rhabdomyosarcoma cells

    NARCIS (Netherlands)

    Komdeur, R; Meijer, C; Van Zweeden, M; De Jong, S; Wesseling, J; Hoekstra, HJ; van der Graaf, WTA

    Doxorubicin (DOX) and ifosfamide (IFO) are the most active single agents in soft tissue sarcomas (STS). Tumour necrosis factor-alpha (TNF-alpha) is used for STS in the setting of isolated limb perfusions. Like TNF-alpha, TNF-related apoptosis-inducing ligand (TRAIL) induces apoptosis. In contrast to

  18. Meloxicam increases intracellular accumulation of doxorubicin via downregulation of multidrug resistance-associated protein 1 (MRP1) in A549 cells.

    Science.gov (United States)

    Chen, S F; Zhang, Z Y; Zhang, J L

    2015-11-19

    It has been suggested that selected COX inhibitors can overcome multidrug resistance through the inhibition of ATP‑binding cassette-transporter proteins thereby enhancing the inhibitory effect of doxorubicin on human tumor growth and promoting the actions of cytostatics. However, their effect on lung cancer and the molecular mechanisms involved in the overcoming of multidrug resistance are unclear. In the present study, the ability of meloxicam, a COX-2-specific inhibitor to enhance doxorubicin‑mediated inhibition was investigated in human A549 lung cancer in vivo and in vitro. In order to unravel the molecular mechanisms involved in doxorubicin accumulation, we measured the levels of multidrug resistance-associated protein (MRP)-transporter protein activity and expression by western blotting, since this has been implicated in meloxicam action as well as in chemoresistance. We found that, in A549 cells, meloxicam could increase intracellular accumulation of doxorubicin, a substrate for MRP, through inhibition of cellular export. Western blot analysis indicated that meloxicam reduced the expression of MRP1 and MRP4. The results reported in the present study demonstrate for the first time that the specific COX-2 inhibitor meloxicam can increase the intracellular accumulation of doxorubicin and enhance doxorubicin-induced cytotoxicity in A549 cancer cells by reducing the expression of MRP1 and MRP4.

  19. DNA methylation-independent reversion of gemcitabine resistance by hydralazine in cervical cancer cells.

    Science.gov (United States)

    Candelaria, Myrna; de la Cruz-Hernandez, Erick; Taja-Chayeb, Lucia; Perez-Cardenas, Enrique; Trejo-Becerril, Catalina; Gonzalez-Fierro, Aurora; Chavez-Blanco, Alma; Soto-Reyes, Ernesto; Dominguez, Guadalupe; Trujillo, Jaenai E; Diaz-Chavez, Jose; Duenas-Gonzalez, Alfonso

    2012-01-01

    Down regulation of genes coding for nucleoside transporters and drug metabolism responsible for uptake and metabolic activation of the nucleoside gemcitabine is related with acquired tumor resistance against this agent. Hydralazine has been shown to reverse doxorubicin resistance in a model of breast cancer. Here we wanted to investigate whether epigenetic mechanisms are responsible for acquiring resistance to gemcitabine and if hydralazine could restore gemcitabine sensitivity in cervical cancer cells. The cervical cancer cell line CaLo cell line was cultured in the presence of increasing concentrations of gemcitabine. Down-regulation of hENT1 & dCK genes was observed in the resistant cells (CaLoGR) which was not associated with promoter methylation. Treatment with hydralazine reversed gemcitabine resistance and led to hENT1 and dCK gene reactivation in a DNA promoter methylation-independent manner. No changes in HDAC total activity nor in H3 and H4 acetylation at these promoters were observed. ChIP analysis showed H3K9m2 at hENT1 and dCK gene promoters which correlated with hyper-expression of G9A histone methyltransferase at RNA and protein level in the resistant cells. Hydralazine inhibited G9A methyltransferase activity in vitro and depletion of the G9A gene by iRNA restored gemcitabine sensitivity. Our results demonstrate that acquired gemcitabine resistance is associated with DNA promoter methylation-independent hENT1 and dCK gene down-regulation and hyper-expression of G9A methyltransferase. Hydralazine reverts gemcitabine resistance in cervical cancer cells via inhibition of G9A histone methyltransferase.

  20. DNA methylation-independent reversion of gemcitabine resistance by hydralazine in cervical cancer cells.

    Directory of Open Access Journals (Sweden)

    Myrna Candelaria

    Full Text Available BACKGROUND: Down regulation of genes coding for nucleoside transporters and drug metabolism responsible for uptake and metabolic activation of the nucleoside gemcitabine is related with acquired tumor resistance against this agent. Hydralazine has been shown to reverse doxorubicin resistance in a model of breast cancer. Here we wanted to investigate whether epigenetic mechanisms are responsible for acquiring resistance to gemcitabine and if hydralazine could restore gemcitabine sensitivity in cervical cancer cells. METHODOLOGY/PRINCIPAL FINDINGS: The cervical cancer cell line CaLo cell line was cultured in the presence of increasing concentrations of gemcitabine. Down-regulation of hENT1 & dCK genes was observed in the resistant cells (CaLoGR which was not associated with promoter methylation. Treatment with hydralazine reversed gemcitabine resistance and led to hENT1 and dCK gene reactivation in a DNA promoter methylation-independent manner. No changes in HDAC total activity nor in H3 and H4 acetylation at these promoters were observed. ChIP analysis showed H3K9m2 at hENT1 and dCK gene promoters which correlated with hyper-expression of G9A histone methyltransferase at RNA and protein level in the resistant cells. Hydralazine inhibited G9A methyltransferase activity in vitro and depletion of the G9A gene by iRNA restored gemcitabine sensitivity. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that acquired gemcitabine resistance is associated with DNA promoter methylation-independent hENT1 and dCK gene down-regulation and hyper-expression of G9A methyltransferase. Hydralazine reverts gemcitabine resistance in cervical cancer cells via inhibition of G9A histone methyltransferase.

  1. Comparative promoter analysis of doxorubicin resistance-associated genes suggests E47 as a key regulatory element.

    Science.gov (United States)

    Gyorffy, András; Vásárhelyi, Barna; Szöke, Dominika; Dietel, Manfred; Tulassay, Tivadar; Györffy, Balázs

    2006-01-01

    Working under the assumption that up- or downregulation of genes implicated in chemoresistance may be the result of altered function of regulatory transcription factors (TF), over-represented TF-binding sites of gene lists previously associated with doxorubicin resistance were the target of our search. First, a data warehouse was set up containing 52 genes which were present in at least two gene lists; of those, proximal promoter sequences (1 kb upstream and 0.05 kb downstream of the transcriptional start sites) could be retrieved from genomic databases for 45 genes using the EZ-Retrieve. The TOUCAN tool MotifScanner, which searches the TRANSFAC database, was used to detect TF-binding sites (TFBSs) in our set of sequences. The statistics tool of the Java program TOUCAN was applied to the data with the appropriate expected frequencies file to compare the measured prevalence to a background model. The most significantly over-represented TFBS was that of E47 (p=0.00024, prevalence: 0.2 vs. background: 8.19E-6). In summary, based on the results of our analysis it is hypothesized that the E47 transcription factor may contribute to doxorubicin resistance.

  2. Gene expression and pathway analysis of ovarian cancer cells selected for resistance to cisplatin, paclitaxel, or doxorubicin

    Directory of Open Access Journals (Sweden)

    Sherman-Baust Cheryl A

    2011-12-01

    Full Text Available Abstract Background Resistance to current chemotherapeutic agents is a major cause of therapy failure in ovarian cancer patients, but the exact mechanisms leading to the development of drug resistance remain unclear. Methods To better understand mechanisms of drug resistance, and possibly identify novel targets for therapy, we generated a series of drug resistant ovarian cancer cell lines through repeated exposure to three chemotherapeutic drugs (cisplatin, doxorubicin, or paclitaxel, and identified changes in gene expression patterns using Illumina whole-genome expression microarrays. Validation of selected genes was performed by RT-PCR and immunoblotting. Pathway enrichment analysis using the KEGG, GO, and Reactome databases was performed to identify pathways that may be important in each drug resistance phenotype. Results A total of 845 genes (p Conclusions Ovarian cancer cells develop drug resistance through different pathways depending on the drug used in the generation of chemoresistance. A better understanding of these mechanisms may lead to the development of novel strategies to circumvent the problem of drug resistance.

  3. NSC23925, identified in a high-throughput cell-based screen, reverses multidrug resistance.

    Directory of Open Access Journals (Sweden)

    Zhenfeng Duan

    2009-10-01

    Full Text Available Multidrug resistance (MDR is a major factor which contributes to the failure of cancer chemotherapy, and numerous efforts have been attempted to overcome MDR. To date, none of these attempts have yielded a tolerable and effective therapy to reverse MDR; thus, identification of new agents would be useful both clinically and scientifically.To identify small molecule compounds that can reverse chemoresistance, we developed a 96-well plate high-throughput cell-based screening assay in a paclitaxel resistant ovarian cancer cell line. Coincubating cells with a sublethal concentration of paclitaxel in combination with each of 2,000 small molecule compounds from the National Cancer Institute Diversity Set Library, we identified a previously uncharacterized molecule, NSC23925, that inhibits Pgp1 and reverses MDR1 (Pgp1 but does not inhibit MRP or BCRP-mediated MDR. The cytotoxic activity of NSC23925 was further evaluated using a panel of cancer cell lines expressing Pgp1, MRP, and BCRP. We found that at a concentration of >10 microM NSC23925 moderately inhibits the proliferation of both sensitive and resistant cell lines with almost equal activity, but its inhibitory effect was not altered by co-incubation with the Pgp1 inhibitor, verapamil, suggesting that NSC23925 itself is not a substrate of Pgp1. Additionally, NSC23925 increases the intracellular accumulation of Pgp1 substrates: calcein AM, Rhodamine-123, paclitaxel, mitoxantrone, and doxorubicin. Interestingly, we further observed that, although NSC23925 directly inhibits the function of Pgp1 in a dose-dependent manner without altering the total expression level of Pgp1, NSC23925 actually stimulates ATPase activity of Pgp, a phenomenon seen in other Pgp inhibitors.The ability of NSC23925 to restore sensitivity to the cytotoxic effects of chemotherapy or to prevent resistance could significantly benefit cancer patients.

  4. Phase 1/2 Study of Atrasentan Combined with Pegylated Liposomal Doxorubicin in Platinum-Resistant Recurrent Ovarian Cancer

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    Petronella O. Witteveen

    2010-11-01

    Full Text Available BACKGROUND: Ovarian cancer overexpresses ET-1, and in vitro studies have shown that ET-1 confers resistance to anthracycline-containing chemotherapy. Atrasentan has been developed as an oral selective endothelin-A receptor antagonist. The objective of the study was to investigate the feasibility and toxicity of adding increasing doses of atrasentan (to a maximum of 10 mg/d and liposomal doxorubicin in patients with progressive ovarian cancer, refractory for platinum and paclitaxel. METHODS:Patients with platinum-resistant ovarian cancer were treated with pegylated liposomal doxorubicin (PLD 50 mg/m2 on day 1 (and repeated every 4 weeks in combination with escalating doses of atrasentan once daily. The starting dose was 2.5 mg and escalated in cohorts of three patients from 5 to 10 mg. RESULTS:Twenty-six patients (mean age = 60 years, range = 42–74 years were treated at the three dose levels. Atrasentan could be safely administered in combination at a dose of 10 mg. All patients were evaluable for toxicity, and 19 patients, included in the phase 2 period, were evaluable for response. Adverse events included nausea, vomiting, mucositis, skin toxicity, and rhinitis. Clinical cardiac toxicity, intensively monitored, was not observed, although two patients had a decrease in cardiac ejection fraction. Three objective responses were observed and another six patients had stable disease with a median time to progression of 14 weeks and an overall survival of 13.1 months. CONCLUSIONS:The addition of atrasentan to standard dose PLD in platinum-resistant ovarian cancer is feasible with some suggestion of prolonged survival.

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

    Directory of Open Access Journals (Sweden)

    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

  6. Synthesis and Biological Activities of a 3'-Azido Analogue of Doxorubicin Against Drug-Resistant Cancer Cells

    Directory of Open Access Journals (Sweden)

    Fengshan Wang

    2012-03-01

    Full Text Available Doxorubicin (DOX, an anthracycline antibiotic, is one of the most active anticancer chemotherapeutic agents. The clinical use of DOX, however, is limited by the dose-dependant P-glycoprotein (P-gp-mediated resistance. Herein, a 3′-azido analogue of DOX (ADOX was prepared from daunorubicin (DNR. ADOX exhibited potent antitumor activities in drug-sensitive (MCF-7 and K562 and drug-resistant cell lines (MCF-7/DNR, K562/DOX, respectively. The drug resistance index (DRI values of ADOX were much lower than that of DOX. The cytotoxicity experiments of ADOX or DOX against K562/DOX, with or without P-gp inhibitor, indicated that ADOX circumvents resistance by abolishing the P-gp recognition. This conclusion was further supported by drug influx/efflux flow cytometry experiments, as well as by molecular docking of ADOX to P-gp. In vivo animal tests, ADOX exhibited higher activity and less toxicity than DOX. The current data warranted ADOX for additional pre-clinical evaluations for new drug development.

  7. reverse transcriptase inhibitors drug resistance mutations in drug ...

    African Journals Online (AJOL)

    2011-01-01

    Jan 1, 2011 ... REVERSE TRANSCRIPTASE INHIBITORS DRUG RESISTANCE MUTATIONS IN DRUG-NAIVE HIV TYPE 1 POSITIVE ... S. A. Khamadi, BSc, MSc, PhD, Senior Research Scientist, Centre for Virus Research, Kenya Medical Research Institute, ... NNRTI associated resistance mutations were present.

  8. Quinolone Resistance Reversion by Targeting the SOS Response.

    Science.gov (United States)

    Recacha, E; Machuca, J; Díaz de Alba, P; Ramos-Güelfo, M; Docobo-Pérez, F; Rodriguez-Beltrán, J; Blázquez, J; Pascual, A; Rodríguez-Martínez, J M

    2017-10-10

    Suppression of the SOS response has been postulated as a therapeutic strategy for potentiating antimicrobial agents. We aimed to evaluate the impact of its suppression on reversing resistance using a model of isogenic strains of Escherichia coli representing multiple levels of quinolone resistance. E. coli mutants exhibiting a spectrum of SOS activity were constructed from isogenic strains carrying quinolone resistance mechanisms with susceptible and resistant phenotypes. Changes in susceptibility were evaluated by static (MICs) and dynamic (killing curves or flow cytometry) methodologies. A peritoneal sepsis murine model was used to evaluate in vivo impact. Suppression of the SOS response was capable of resensitizing mutant strains with genes encoding three or four different resistance mechanisms (up to 15-fold reductions in MICs). Killing curve assays showed a clear disadvantage for survival (Δlog10 CFU per milliliter [CFU/ml] of 8 log units after 24 h), and the in vivo efficacy of ciprofloxacin was significantly enhanced (Δlog10 CFU/g of 1.76 log units) in resistant strains with a suppressed SOS response. This effect was evident even after short periods (60 min) of exposure. Suppression of the SOS response reverses antimicrobial resistance across a range of E. coli phenotypes from reduced susceptibility to highly resistant, playing a significant role in increasing the in vivo efficacy.IMPORTANCE The rapid rise of antibiotic resistance in bacterial pathogens is now considered a major global health crisis. New strategies are needed to block the development of resistance and to extend the life of antibiotics. The SOS response is a promising target for developing therapeutics to reduce the acquisition of antibiotic resistance and enhance the bactericidal activity of antimicrobial agents such as quinolones. Significant questions remain regarding its impact as a strategy for the reversion or resensitization of antibiotic-resistant bacteria. To address this

  9. Salt Concentration Differences Alter Membrane Resistance in Reverse Electrodialysis Stacks

    KAUST Repository

    Geise, Geoffrey M.

    2014-01-14

    Membrane ionic resistance is usually measured by immersing the membrane in a salt solution at a single, fixed concentration. While salt concentration is known to affect membrane resistance when the same concentration is used on both sides of the membrane, little is known about membrane resistance when the membrane is placed between solutions of different concentrations, such as in a reverse electrodialysis (RED) stack. Ionic resistance measurements obtained using Selemion CMV and AMV that separated sodium chloride and ammonium bicarbonate solutions of different concentrations were greater than those measured using only the high-concentration solution. Measured RED stack resistances showed good agreement with resistances calculated using an equivalent series resistance model, where the membranes accounted for 46% of the total stack resistance. The high area resistance of the membranes separating different salt concentration solutions has implications for modeling and optimizing membranes used in RED systems.

  10. Extracorporeal Elimination of Circulating Pegylated Liposomal Doxorubicin (PLD) to Enhance the Benefit of Cytostatic Therapy in Platinum-Resistant Ovarian Cancer Patients.

    Science.gov (United States)

    Kubeček, Ondřej; Bláha, Milan; Diaz-Garcia, Daniel; Filip, Stanislav

    2015-01-01

    Ovarian cancer is the fifth most common malignancy in the world's female population and with the highest lethality index among gynecological tumors. The prognosis of metastatic disease is usually poor, especially in platinum-resistant cases. There are several options for the treatment of metastatic disease resistant to platinum derivates (e.g. paclitaxel, topotecan and pegylated liposomal doxorubicin), all of which are considered equipotent. Pegylated liposomal doxorubicin (PLD) is a liposomal form of the anthracycline antibiotic doxorubicin. It is characterized by more convenient pharmacokinetics and a different toxicity profile. Cardiotoxicity, the major adverse effect of conventional doxorubicin, is reduced in PLD as well as hematotoxicity, alopecia, nausea and vomiting. Skin toxicity and mucositis, however, emerge as serious issues since they represent dose and schedule-limiting toxicities. The pharmacokinetics of PLD (prolonged biological half-life and preferential distribution into tumor tissue) provide new possibilities to address these toxicity issues. The extracorporeal elimination of circulating liposomes after PLD saturation in the tumor tissue represents a novel and potent strategy to diminish drug toxicity. This article intends to review PLD characteristics and the importance of extracorporeal elimination to enhance treatment tolerance and benefits.

  11. Extracorporeal Elimination of Circulating Pegylated Liposomal Doxorubicin (PLD to Enhance the Benefit of Cytostatic Therapy in Platinum-Resistant Ovarian Cancer Patients

    Directory of Open Access Journals (Sweden)

    Ondřej Kubeček

    2015-07-01

    Full Text Available Ovarian cancer is the fifth most common malignancy in the world’s female population and with the highest lethality index among gynecological tumors. The prognosis of metastatic disease is usually poor, especially in platinum-resistant cases. There are several options for the treatment of metastatic disease resistant to platinum derivates (e.g. paclitaxel, topotecan and pegylated liposomal doxorubicin, all of which are considered equipotent. Pegylated liposomal doxorubicin (PLD is a liposomal form of the anthracycline antibiotic doxorubicin. It is characterized by more convenient pharmacokinetics and a different toxicity profile. Cardiotoxicity, the major adverse effect of conventional doxorubicin, is reduced in PLD as well as hematotoxicity, alopecia, nausea and vomiting. Skin toxicity and mucositis, however, emerge as serious issues since they represent dose and schedule-limiting toxicities. The pharmacokinetics of PLD (prolonged biological half-life and preferential distribution into tumor tissue provide new possibilities to address these toxicity issues. The extracorporeal elimination of circulating liposomes after PLD saturation in the tumor tissue represents a novel and potent strategy to diminish drug toxicity. This article intends to review PLD characteristics and the importance of extracorporeal elimination to enhance treatment tolerance and benefits.

  12. Sensitivity and resistance towards isoliquiritigenin, doxorubicin and methotrexate in T cell acute lymphoblastic leukaemia cell lines by pharmacogenomics.

    Science.gov (United States)

    Youns, Mahmoud; Fu, Yu-Jie; Zu, Yuan-Gang; Kramer, Anne; Konkimalla, V Badireenath; Radlwimmer, Bernhard; Sültmann, Holger; Efferth, Thomas

    2010-09-01

    The development of drug resistance in cancer cells necessitates the identification of novel agents with improved activity towards cancer cells. In the present investigation, we compared the cytotoxicity of the chalcone flavonoide, isoliquiritigenin (ISL), with that of doxorubicin (DOX) and methotrexate (MTX) in five T cell acute lymphoblastic leukaemia (T-ALL) cell lines (Jurkat, J-Jhan, J16, HUT78 and Karpas 45). To gain insight into the molecular mechanisms which determine the response of T-ALL cells towards ISL, DOX and MTX, we applied array-based matrix comparative genomic hybridisation and microarray-based mRNA expression profiling and compared the genomic and transcriptomic profiles of the cell lines with their 50% inhibition (IC(50)) values for these three drugs. The IC(50) values for ISL did not correlate with those for DOX or MTX, indicating that ISL was still active in DOX- or MTX-unresponsive cell lines. Likewise, the genomic imbalances of chromosomal clones and mRNA expression profile significantly correlating with IC(50) values for ISL were different from thoses correlating with IC(50) values for DOX and MTX. In conclusion, ISL represents a cytotoxic natural product with activity towards T-ALL cell lines. There was no cross-resistance between ISL and DOX or MTX, and the genomic and transcriptomic profiles pointed to different molecular modes of action of ISL as compared to DOX and MTX, indicating that ISL may be a valuable adjunct for cancer therapy to treat otherwise drug-resistant tumours.

  13. Nickel-cadmium battery cell reversal from resistive network effects

    Science.gov (United States)

    Zimmerman, A. H.

    1985-07-01

    During the individual cell short-down procedures often used for storing or reconditioning nickel-cadmium (Ni-Cd) batteries, it is possible for significant reversal of the lowest capacity cells to occur. The reversal is caused by the finite resistance of the common current-carrying leads in the resistive network that is generally used during short-down. A model is developed to evaluate the extent of such a reversal in any specific battery, and the model is verified by means of data from the short-down of a f-cell, 3.5-Ah battery. Computer simulations of short-down on a variety of battery configurations indicate the desirability of controlling capacity imbalances arising from cell configuration and battery management, limiting variability in the short-down resistors, minimizing lead resistances, and optimizing lead configurations.

  14. Preclinical in vivo activity of a combination gemcitabine/liposomal doxorubicin against cisplatin-resistant human ovarian cancer (A2780/CDDP).

    Science.gov (United States)

    Gallo, D; Fruscella, E; Ferlini, C; Apollonio, P; Mancuso, S; Scambia, G

    2006-01-01

    Both gemcitabine and liposomal doxorubicin are antineoplastic drugs with clinical activity in platinum-refractory ovarian cancer. The purpose of this study was to evaluate the antitumor activity of a combination gemcitabine/liposomal doxorubicin administered to athymic mice bearing cisplatin-resistant human ovarian cancer (A2780/CDDP) xenografts. Emphasis was on the use of very low doses of each drug and of different dosing schedules. Data obtained showed that combined treatment with 80 mg/kg gemcitabine and 15 mg/kg liposomal doxorubicin produced a significant enhancement of antitumor activity compared with monotherapy at the same doses of these agents. Noteworthy is the fact that the majority of xenograft-bearing animals receiving the combination therapy demonstrated a complete tumor regression at the end of the study. A similar trend was observed when doses of both drugs were reduced to 20 mg/kg gemcitabine and to 6 mg/kg liposomal doxorubicin. Again, three out of ten mice receiving the combination were tumor free at the end of the study. No significant differences were observed in antitumor activity when comparing the simultaneous vs the consecutive dosing schedule. Remarkably, no additive toxicity was observed in any experimental trials. These data encourage clinical trials to prove the advantages of this combination treatment with respect to the single-agent chemotherapy in platinum-refractory ovarian cancer patients.

  15. Pegylated Liposomal Doxorubicin Is an Active Agent for Chemotherapy-Resistant Choriocarcinoma: A Report of Two Cases.

    Science.gov (United States)

    Popadiuk, Catherine; Power, Patti

    2016-01-01

    Despite advances in chemotherapy, radiation, surgery, and supportive treatments, a significant proportion of high-risk metastatic gestational trophoblastic disease patients develop resistant disease and die. Of those cured, protracted treatments can lead to long-term morbidity or later toxicity and death. Here we describe 2 patients with brain metastases who failed multiple lines of standard chemotherapy and radiation but had complete response to pegylated liposomal doxorubicin (PLD). A 35-year-old woman presented with choriocarcinoma in the brain, lungs, and subcutaneous tissues 11 months after full-term delivery. Her FIGO risk score was 14. Over 3 years she was treated with EMA-CO, EMA-CE, Taxol, gemcitabine, brain radiation, and excisional craniotomy for recurrent choriocarcinoma. She showed complete response of choriocarcinoma brain metastases following 2 cycles of PLD. She was choriocarcinoma free until her death 9 months later from acute myelogenous leukemia. A 52-year-old multigravid woman presented with choriocarcinoma 3 years following miscarriage. Her FIGO score was 16. Over 18 months she was treated with EMA-CO, TP/TE and IT MTX, and radiation. Her disease proved resistant and midbrain tumor unresectable. She showed complete response to PLD following 3 cycles but ultimately died from neurologic complications. PLD is an active agent in the treatment of high-risk choriocarcinoma.

  16. Curcumin Reverse Methicillin Resistance in Staphylococcus aureus

    Directory of Open Access Journals (Sweden)

    Su-Hyun Mun

    2014-11-01

    Full Text Available Curcumin, a natural polyphenolic flavonoid extracted from the rhizome of Curcuma longa L., was shown to possess superior potency to resensitize methicillin-resistant Staphylococcus aureus (MRSA to antibiotics. Previous studies have shown the synergistic activity of curcumin with β-lactam and quinolone antibiotics. Further, to understand the anti-MRSA mechanism of curcumin, we investigated the potentiated effect of curcumin by its interaction in diverse conditions. The mechanism of anti-MRSA action of curcumin was analyzed by the viability assay in the presence of detergents, ATPase inhibitors and peptidoglycan (PGN from S. aureus, and the PBP2a protein level was analyzed by western blotting. The morphological changes in the curcumin-treated MRSA strains were investigated by transmission electron microscopy (TEM. We analyzed increased susceptibility to MRSA isolates in the presence of curcumin. The optical densities at 600 nm (OD600 of the suspensions treated with the combinations of curcumin with triton X-100 and Tris were reduced to 63% and 59%, respectively, compared to curcumin without treatment. N,N'-dicyclohexylcarbodiimide (DCCD and sodium azide (NaN3 were reduced to 94% and 55%, respectively. When peptidoglycan (PGN from S. aureus was combined with curcumin, PGN (0–125 μg/mL gradually blocked the antibacterial activity of curcumin (125 μg/mL; however, at a concentration of 125 µg/mL PGN, it did not completely block curcumin. Curcumin has a significant effect on the protein level of PBP2a. The TEM images of MRSA showed damage of the cell wall, disruption of the cytoplasmic contents, broken cell membrane and cell lysis after the treatment of curcumin. These data indicate a remarkable antibacterial effect of curcumin, with membrane permeability enhancers and ATPase inhibitors, and curcumin did not directly bind to PGN on the cell wall. Further, the antimicrobial action of curcumin involved in the PBP2a-mediated resistance mechanism was

  17. Quinolone Resistance Reversion by Targeting the SOS Response

    Directory of Open Access Journals (Sweden)

    E. Recacha

    2017-10-01

    Full Text Available Suppression of the SOS response has been postulated as a therapeutic strategy for potentiating antimicrobial agents. We aimed to evaluate the impact of its suppression on reversing resistance using a model of isogenic strains of Escherichia coli representing multiple levels of quinolone resistance. E. coli mutants exhibiting a spectrum of SOS activity were constructed from isogenic strains carrying quinolone resistance mechanisms with susceptible and resistant phenotypes. Changes in susceptibility were evaluated by static (MICs and dynamic (killing curves or flow cytometry methodologies. A peritoneal sepsis murine model was used to evaluate in vivo impact. Suppression of the SOS response was capable of resensitizing mutant strains with genes encoding three or four different resistance mechanisms (up to 15-fold reductions in MICs. Killing curve assays showed a clear disadvantage for survival (Δlog10 CFU per milliliter [CFU/ml] of 8 log units after 24 h, and the in vivo efficacy of ciprofloxacin was significantly enhanced (Δlog10 CFU/g of 1.76 log units in resistant strains with a suppressed SOS response. This effect was evident even after short periods (60 min of exposure. Suppression of the SOS response reverses antimicrobial resistance across a range of E. coli phenotypes from reduced susceptibility to highly resistant, playing a significant role in increasing the in vivo efficacy.

  18. Thymoquinone up-regulates PTEN expression and induces apoptosis in doxorubicin-resistant human breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Arafa, El-Shaimaa A.; Zhu Qianzheng [Department of Radiology, Ohio State University, Columbus, OH 43210 (United States); Shah, Zubair I. [James Cancer Hospital and Solove Research Institute, Ohio State University, Columbus, OH 43210 (United States); Wani, Gulzar; Barakat, Bassant M.; Racoma, Ira [Department of Radiology, Ohio State University, Columbus, OH 43210 (United States); El-Mahdy, Mohamed A., E-mail: Mohamed.el-mahdy@osumc.edu [Department of Radiology, Ohio State University, Columbus, OH 43210 (United States); Wani, Altaf A., E-mail: wani.2@osu.edu [Department of Radiology, Ohio State University, Columbus, OH 43210 (United States); Department of Molecular and Cellular Biochemistry, Ohio State University, Columbus, OH 43210 (United States); James Cancer Hospital and Solove Research Institute, Ohio State University, Columbus, OH 43210 (United States); DNA Research Chair, King Saud University, Riyadh (Saudi Arabia)

    2011-01-10

    The use of innocuous naturally occurring compounds to overcome drug resistance and cancer recalcitrance is now in the forefront of cancer research. Thymoquinone (TQ) is a bioactive constituent of the volatile oil derived from seeds of Nigella sativa Linn. TQ has shown promising anti-carcinogenic and anti-tumor activities through different mechanisms. However, the effect of TQ on cell signaling and survival pathways in resistant cancer cells has not been fully delineated. Here, we report that TQ greatly inhibits doxorubicin-resistant human breast cancer MCF-7/DOX cell proliferation. TQ treatment increased cellular levels of PTEN proteins, resulting in a substantial decrease of phosphorylated Akt, a known regulator of cell survival. The PTEN expression was accompanied with elevation of PTEN mRNA. TQ arrested MCF-7/DOX cells at G2/M phase and increased cellular levels of p53 and p21 proteins. Flow cytometric analysis and agarose gel electrophoresis revealed a significant increase in Sub-G1 cell population and appearance of DNA ladders following TQ treatment, indicating cellular apoptosis. TQ-induced apoptosis was associated with disrupted mitochondrial membrane potential and activation of caspases and PARP cleavage in MCF-7/DOX cells. Moreover, TQ treatment increased Bax/Bcl2 ratio via up-regulating Bax and down-regulating Bcl2 proteins. More importantly, PTEN silencing by target specific siRNA enabled the suppression of TQ-induced apoptosis resulting in increased cell survival. Our results reveal that up-regulation of the key upstream signaling factor, PTEN, in MCF-7/DOX cells inhibited Akt phosphorylation, which ultimately causes increase in their regulatory p53 levels affecting the induction of G2/M cell cycle arrest and apoptosis. Overall results provide mechanistic insights for understanding the molecular basis and utility of the anti-tumor activity of TQ.

  19. Development of Bioactive PEGylated Nanostructured Platforms for Sequential Delivery of Doxorubicin and Imatinib to Overcome Drug Resistance in Metastatic Tumors.

    Science.gov (United States)

    Gupta, Biki; Ramasamy, Thiruganesh; Poudel, Bijay Kumar; Pathak, Shiva; Regmi, Shobha; Choi, Ju Yeon; Son, Youlim; Thapa, Raj Kumar; Jeong, Jee-Heon; Kim, Jae Ryong; Choi, Han-Gon; Yong, Chul Soon; Kim, Jong Oh

    2017-03-22

    Metastasis of cancers accounts for almost all cancer-related deaths. In this study, we report a PEGylated nanostructured platform for coadministration of doxorubicin (DOX) and imatinib (IMT) intended to effectively inhibit metastatic tumors. The DOX and IMT coloaded nanostructured system (DOX/IMT-N) is characterized by an excellent encapsulation potential for both drugs and shows sequential and sustained drug release in vitro. DOX/IMT-N significantly inhibited the in vitro proliferation of MDA-MB-231 and SK-MEL-28 cells. The inhibitory effect on in vitro proliferation of the cells was significantly greater than the effect of free DOX, DOX/IMT cocktail, or the nanostructured system housing DOX only (DOX-N). DOX/IMT-N remarkably enhanced cellular drug uptake, resulting in enhanced apoptosis, caused by significant increases in the expression levels of apoptotic marker proteins. Intravenous administration of DOX/IMT-N to MBA-MB-231 xenograft tumor-bearing mice resulted in significantly improved inhibition of tumor progression compared to that with DOX, DOX/IMT, or DOX-N. Therefore, the nanostructured DOX/IMT-N system could potentially aid in overcoming drug resistance in metastatic tumors and improve the effectiveness of metastatic tumor therapeutics.

  20. A Near-Infrared Photothermal Effect-Responsive Drug Delivery System Based on Indocyanine Green and Doxorubicin-Loaded Polymeric Micelles Mediated by Reversible Diels-Alder Reaction.

    Science.gov (United States)

    Li, Hui; Li, Junjie; Ke, Wendong; Ge, Zhishen

    2015-10-01

    Near-infrared light (NIR) possesses great advantages for light-responsive controllable drug release, such as deep tissue penetration and low damage to healthy tissues. Herein, a NIR-responsive drug delivery system is developed based on a NIR dye, indocyanine green (ICG), and anticancer drug, doxorubicin (DOX)-loaded thermoresponsive block copolymer micelles, in which the drug release can be controlled via NIR irradiation. First, block copolymers, poly(oligo(ethylene glycol) methacrylate)-block-poly(furfuryl methacrylate) (POEGMA-b-PFMA), are synthesized by sequential reversible addition-fragmentation chain-transfer (RAFT) polymerization, followed by modification with N-octyl maleimide through Diels-Alder (DA) reaction to produce POEGMA-b-POMFMA. The self-assembly of POEGMA-b-POMFMA by nano-precipitation in aqueous solution affords the polymeric micelles which are used to simultaneously encapsulate ICG and DOX. Upon irradiation by NIR light (805 nm), the loaded DOX is released rapidly from the micelles due to partial retro DA reaction and local temperature increase-induced faster drug diffusion by the photothermal effect. Cytotoxicity evaluation and intracellular distribution observation demonstrate significant synergistic effects of NIR-triggered drug release, photothermal, and chemotherapy toward cancer cells under NIR irradiation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Persistence and reversal of plasmid-mediated antibiotic resistance.

    Science.gov (United States)

    Lopatkin, Allison J; Meredith, Hannah R; Srimani, Jaydeep K; Pfeiffer, Connor; Durrett, Rick; You, Lingchong

    2017-11-22

    In the absence of antibiotic-mediated selection, sensitive bacteria are expected to displace their resistant counterparts if resistance genes are costly. However, many resistance genes persist for long periods in the absence of antibiotics. Horizontal gene transfer (primarily conjugation) could explain this persistence, but it has been suggested that very high conjugation rates would be required. Here, we show that common conjugal plasmids, even when costly, are indeed transferred at sufficiently high rates to be maintained in the absence of antibiotics in Escherichia coli. The notion is applicable to nine plasmids from six major incompatibility groups and mixed populations carrying multiple plasmids. These results suggest that reducing antibiotic use alone is likely insufficient for reversing resistance. Therefore, combining conjugation inhibition and promoting plasmid loss would be an effective strategy to limit conjugation-assisted persistence of antibiotic resistance.

  2. N-alkanol-N-cyclohexanol amine aryl esters: Multidrug resistance (MDR) reversing agents with high potency and efficacy.

    Science.gov (United States)

    Teodori, Elisabetta; Dei, Silvia; Coronnello, Marcella; Floriddia, Elisa; Bartolucci, Gianluca; Manetti, Dina; Romanelli, Maria Novella; Santo Domingo Porqueras, Diego; Salerno, Milena

    2017-02-15

    In a continuing search for potent P-gp-dependent multidrug-resistant (MDR) reversers we synthesized and studied a new series of N-alkanol-N-cyclohexanol amine aryl esters characterized by the presence of two linkers with different flexibility: a polymethylene chain of variable length and a cyclohexylic scaffold, that gave origin to two geometrical isomers (cis and trans). The reversal activity of the new compounds was evaluated on the K562/DOX cell line by three tests: pirarubicin uptake modulation, doxorubicin cytotoxicity enhancement (reversal fold, RF) and inhibition of P-gp-mediated rhodamine-123 (Rhd 123) efflux tests. The chemical stability of their ester function was evaluated in the experimental conditions utilized (phosphate buffer solution (PBS), bovine serum and in the presence of K562/DOX cells) and in human plasma. The new series of molecules showed very interesting MDR reversing properties; in particular compound 5b (ELF26B), characterized by trans stereochemistry and a 5-methylene chain, presented the best pharmacological profile and is stable in each tested medium. Compound 5b could be an interesting lead for the development of new potent and efficacious P-gp-dependent MDR modulators. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  3. Phase II study of bevacizumab with liposomal doxorubicin for patients with platinum- and taxane-resistant ovarian cancer.

    Science.gov (United States)

    Verschraegen, C F; Czok, S; Muller, C Y; Boyd, L; Lee, S J; Rutledge, T; Blank, S; Pothuri, B; Eberhardt, S; Muggia, F

    2012-12-01

    Suppression of neoangiogenesis and pegylated liposomal doxorubicin (PLD) each contribute to the management of platinum-resistant/refractory ovarian cancer. The aim of this study is to test the combination of bevacizumab and PLD in women with resistant or refractory ovarian cancer. Eligibility criteria were no more than two prior treatments with platinum-containing regimens and one additional regimen, without anthracyclines. Treatment was administered every 3 weeks (bevacizumab 15 mg/kg beginning on cycle 2 and PLD 30 mg/m(2)). The primary end point was progression-free survival (PFS) at 6 months; the secondary end points included side-effects, overall response rates (ORR) and survival (OS). Forty-six patients were enrolled. The average number of courses administered was 7. The median PFS was 6.6 months (range 1-24.6 months) according to Gynecologic Cancer Intergroup Committee (GCIC) criteria and 7.8 months (range 2-13.3 months) according to Response Evaluation Criteria in Solid Tumors (RECIST). The median OS was 33.2 months (range 3-37.5+ months). The ORR was 30.2% [95% confidence interval (CI) 17.2-46.1] and the clinical benefit rate (CBR) was 86.1% (95% CI 72.1-94.7). Adverse events included mucosal and dermal erosions (30% grade 3) and asymptomatic cardiac dysfunction. Additional toxic effects included hypertension, headache, renal dysfunction and proteinuria, wound healing delay, and one episode each of central nervous system (CNS) ischemia and hemolytic uremic syndrome. PLD with bevacizumab has improved activity in recurrent ovarian cancer with increased toxicity.

  4. Mechanism Underlying the Reversal of Drug Resistance in P-Glycoprotein-Expressing Leukemia Cells by Pinoresinol and the Study of a Derivative

    Directory of Open Access Journals (Sweden)

    María C. Carpinella

    2017-04-01

    Full Text Available P-glycoprotein (P-gp is a membrane protein associated with multidrug resistance (MDR due to its key role in mediating the traffic of chemotherapeutic drugs outside cancer cells, leading to a cellular response that hinders efforts toward successful therapy. With the aim of finding agents that circumvent the MDR phenotype mediated by P-gp, 15 compounds isolated from native and naturalized plants of Argentina were screened. Among these, the non-cytotoxic lignan (± pinoresinol successfully restored sensitivity to doxorubicin from 7 μM in the P-gp overexpressed human myelogenous leukemia cells, Lucena 1. This resistance-reversing effect was confirmed by competitively increasing the intracellular doxorubicin accumulation and by significantly inhibiting the efflux of doxorubicin and, to a lesser extent, that of rhodamine 123. The activity obtained was similar to that observed with verapamil. No such results were observed in the sensitive parental K562 cell line. To gain deeper insight into the mode of action of pinoresinol, its effect on P-gp function and expression was examined. The docking simulations indicated that the lignan bound to P-gp at the apex of the V-shaped transmembrane cavity, involving transmembrane helices 4, 5, and 6, and partially overlapped the binding region of tariquidar, which was used as a positive control. These results would shed some light on the nature of its interaction with P-gp at molecular level and merit further mechanistic and kinetic studies. In addition, it showed a maximum 29% activation of ATP hydrolysis and antagonized verapamil-stimulated ATPase activity with an IC50 of 20.9 μM. On the other hand, pinoresinol decreased the presence of P-gp in the cell surface. Derivatives of pinoresinol with improved activity were identified by docking studies. The most promising one, the non-cytotoxic 1-acetoxypinoresinol, caused a reversion of doxorubicin resistance from 0.11 μM and thus higher activity than the lead

  5. Sulforaphane increases the efficacy of doxorubicin in mouse fibroblasts characterized by p53 mutations

    Energy Technology Data Exchange (ETDEWEB)

    Fimognari, Carmela [Department of Pharmacology, University of Bologna, Bologna (Italy)]. E-mail: carmela.fimognari@unibo.it; Nuesse, Michael [GSF-Flow Cytometry Group, Neuherberg (Germany); Lenzi, Monia [Department of Pharmacology, University of Bologna, Bologna (Italy); Sciuscio, Davide [Department of Pharmacology, University of Bologna, Bologna (Italy); Cantelli-Forti, Giorgio [Department of Pharmacology, University of Bologna, Bologna (Italy); Hrelia, Patrizia [Department of Pharmacology, University of Bologna, Bologna (Italy)

    2006-10-10

    One novel strategy for increasing cancer chemotherapy efficacy and reversing chemoresistance involves co-administration of natural chemopreventive compounds alongside standard chemotherapeutic protocols. Sulforaphane is a particularly promising chemopreventive agent, which has been shown to exert proapoptotic effects on tumor cells containing p53 mutations. The p53{sup Ser220} mutation has been implicated in reduced efficacy and drug resistance in the context of osteosarcomas and breast tumors treated with doxorubicin-based protocols. We investigated the effects of a combination of doxorubicin and sulforaphane on cell viability and apoptosis induction in fibroblasts characterized by different p53 status (p53 wild-type, p53 knock-out, and p53{sup Ser220} mutation), and identified some of the molecular pathways triggered by the drug combination. Very high concentrations of doxorubicin were necessary to decrease the viability of p53{sup Ser220} and p53 knock-out (but not wild-type) cells. Treatment of p53{sup Ser220} and p53 knock-out cells with doxorubicin did not induce apoptosis, also at very high concentrations (10 {mu}M). Sulforaphane restored chemosensitivity and induced apoptosis in doxorubicin-resistant p53{sup Ser220} and p53 knock-out cells, irrespective of p53 status. The induction of apoptosis was caspase-3 dependent and caspase-8 independent. Bongkrekic acid, a mitochondrial membrane stabilizer, partially prevented the effects of doxorubicin plus sulforaphane on mitochondrial permeability but was unable to prevent the induction of apoptosis. N-acetyl-cysteine, a glutathione precursor, blocked the induction of apoptosis by doxorubicin plus sulforaphane. Considering the negligible safety profile of sulforaphane, our findings could prompt innovative clinical studies designed to investigate whether its coadministration can enhance the efficacy of doxorubicin-based regimens.

  6. NVP-TAE684 reverses multidrug resistance (MDR) in human osteosarcoma by inhibiting P-glycoprotein (PGP1) function.

    Science.gov (United States)

    Ye, Shunan; Zhang, Jianming; Shen, Jacson; Gao, Yan; Li, Ying; Choy, Edwin; Cote, Gregory; Harmon, David; Mankin, Henry; Gray, Nathanael S; Hornicek, Francis J; Duan, Zhenfeng

    2016-02-01

    Increased expression of P-glycoprotein (PGP1) is one of the major causes of multidrug resistance (MDR) in cancer, including in osteosarcoma, which eventually leads to the failure of cancer chemotherapy. Thus, there is an urgent need to develop effective therapeutic strategies to override the expression and function of PGP1 to counter MDR in cancer patients. In an effort to search for new chemical entities targeting PGP1-associated MDR in osteosarcoma, we screened a 500+ compound library of known kinase inhibitors with established kinase selectivity profiles. We aimed to discover potential drug synergistic effects among kinase inhibitors and general chemotherapeutics by combining inhibitors with chemotherapy drugs such as doxorubicin and paclitaxel. The human osteosarcoma MDR cell lines U2OSR2 and KHOSR2 were used for the initial screen and secondary mechanistic studies. After screening 500+ kinase inhibitors, we identified NVP-TAE684 as the most effective MDR reversing agent. NVP-TAE684 significantly reversed chemoresistance when used in combination with doxorubicin, paclitaxel, docetaxel, vincristine, ET-743 or mitoxantrone. NVP-TAE684 itself is not a PGP1 substrate competitive inhibitor, but it can increase the intracellular accumulation of PGP1 substrates in PGP1-overexpressing cell lines. NVP-TAE684 was found to inhibit the function of PGP1 by stimulating PGP1 ATPase activity, a phenomenon reported for other PGP1 inhibitors. The application of NVP-TAE684 to restore sensitivity of osteosarcoma MDR cells to the cytotoxic effects of chemotherapeutics will be useful for further study of PGP1-mediated MDR in human cancer and may ultimately benefit cancer patients. © 2015 The British Pharmacological Society.

  7. Asclepiasterol, a novel C21 steroidal glycoside derived from Asclepias curassavica, reverses tumor multidrug resistance by down-regulating P-glycoprotein expression.

    Science.gov (United States)

    Yuan, Wei-Qi; Zhang, Rong-Rong; Wang, Jun; Ma, Yan; Li, Wen-Xue; Jiang, Ren-Wang; Cai, Shao-Hui

    2016-05-24

    Multidrug resistance (MDR) mediated by P-glycoprotein (P-gp) is a major cause of cancer therapy failure. In this study, we identified a novel C21 steroidal glycoside, asclepiasterol, capable of reversing P-gp-mediated MDR. Asclepiasterol (2.5 and 5.0μM) enhanced the cytotoxity of P-gp substrate anticancer drugs in MCF-7/ADR and HepG-2/ADM cells. MDR cells were more responsive to paclitaxel in the presence of asclepiasterol, and colony formation of MDR cells was only reduced upon treatment with a combination of asclepiasterol and doxorubicin. Consistent with these findings, asclepiasterol treatment increased the intracellular accumulation of doxorubicin and rhodamine 123 (Rh123) in MDR cells. Asclepiasterol decreased expression of P-gp protein without stimulating or suppressing MDR1 mRNA levels. Asclepiasterol-mediated P-gp suppression caused inhibition of ERK1/2 phosphorylation in two MDR cell types, and EGF, an activator of the MAPK/ERK pathway, reversed the P-gp down-regulation, implicating the MAPK/ERK pathway in asclepiasterol-mediated P-gp down-regulation. These results suggest that asclepiasterol could be developed as a modulator for reversing P-gp-mediated MDR in P-gp-overexpressing cancer variants.

  8. Comparative characterization of stem cell marker expression, metabolic activity and resistance to doxorubicin in adherent and spheroid cells derived from the canine prostate adenocarcinoma cell line CT1258.

    Science.gov (United States)

    Liu, Wen; Moulay, Mohammed; Willenbrock, Saskia; Roolf, Catrin; Junghanss, Christian; Ngenazahayo, Anaclet; Nolte, Ingo; Murua Escobar, Hugo

    2015-04-01

    Canine prostate cancer represents a spontaneous animal model for the human counterpart. Cells with stem cell-like character are considered to play a major role in therapeutic resistance and tumor relapse. Thus, the identification of markers allowing for recognition and characterization of these cells is essential. Expression of 12 stem cell marker genes in the canine prostate cancer cell line CT1258 and spheroid cells generated from these was analyzed by quantitative real-time PCR. In CT1258 and the generated spheroid cells, CD44 and CD133 expression was analyzed by flow cytometry, as well as proliferation and doxorubicin resistance. Integrin alpha-6 (ITGA6) expression and metabolic activity were significantly up-regulated in CT1258-derived spheroid cells, while doxorubicin resistance remained comparable. ITGA6 de-regulation and metabolic activity appear to be characteristic of the generated spheres, indicating potential intervention targets. Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  9. Terpenoids from Euphorbia soongarica and Their Multidrug Resistance Reversal Activity.

    Science.gov (United States)

    Gao, Jie; Aisa, Haji A

    2017-06-23

    Ten new terpenoids, including five diterpenoids (1-5), three nortriterpenoids (6-8), and two triterpenoids (9, 10), and 15 known terpenoids (11-25) were isolated from an acetone extract of Euphorbia soongarica. Sooneuphoramine (1) is the first example of a euphoractine B-type diterpenoid alkaloid, while sooneuphanones A-C (6-8) are rare nortriterpenoids from the Euphorbia genus. The isolated terpenoids were tested for their cytotoxicity and multidrug resistance (MDR) reversal activity, 10 of which showed moderate cytotoxicity against the KB and KBv200 cell lines, while 11 compounds exhibited P-gp modulating potential. The triterpenoid sooneuphanone D (9) possessed a remarkable MDR reversal activity much higher than the positive control, verapamil.

  10. Overcoming multidrug resistance using folate receptor-targeted and pH-responsive polymeric nanogels containing covalently entrapped doxorubicin

    Czech Academy of Sciences Publication Activity Database

    Chen, Y.; Tezcan, O.; Li, D.; Beztsinna, N.; Lou, B.; Etrych, Tomáš; Ulbrich, Karel; Metselaar, J. M.; Lammers, T.; Hennink, W. E.

    2017-01-01

    Roč. 9, č. 29 (2017), s. 10404-10419 ISSN 2040-3364 R&D Projects: GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : drug delivery * doxorubicin * pH controlled release Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 7.367, year: 2016

  11. Targeting ABCB1 (MDR1) in multi-drug resistant osteosarcoma cells using the CRISPR-Cas9 system to reverse drug resistance.

    Science.gov (United States)

    Liu, Tang; Li, Zhihong; Zhang, Qing; De Amorim Bernstein, Karen; Lozano-Calderon, Santiago; Choy, Edwin; Hornicek, Francis J; Duan, Zhenfeng

    2016-12-13

    Multi-drug resistance (MDR) remains a significant obstacle to successful chemotherapy treatment for osteosarcoma patients. One of the central causes of MDR is the overexpression of the membrane bound drug transporter protein P-glycoprotein (P-gp), which is the protein product of the MDR gene ABCB1. Though several methods have been reported to reverse MDR in vitro and in vivo when combined with anticancer drugs, they have yet to be proven useful in the clinical setting. The meta-analysis demonstrated that a high level of P-gp may predict poor survival in patients with osteosarcoma. The expression of P-gp can be efficiently blocked by the clustered regularly interspaced short palindromic repeats (CRISPR)-associated Cas9 system (CRISPR-Cas9). Inhibition of ABCB1 was associated with reversing drug resistance in osteosarcoma MDR cell lines (KHOSR2 and U-2OSR2) to doxorubicin. We performed a meta-analysis to investigate the relationship between P-gp expression and survival in patients with osteosarcoma. Then we adopted the CRISPR-Cas9, a robust and highly efficient novel genome editing tool, to determine its effect on reversing drug resistance by targeting endogenous ABCB1 gene at the DNA level in osteosarcoma MDR cell lines. These results suggest that the CRISPR-Cas9 system is a useful tool for the modification of ABCB1 gene, and may be useful in extending the long-term efficacy of chemotherapy by overcoming P-gp-mediated MDR in the clinical setting.

  12. Adverse Event Profile by Folate Receptor Status for Vintafolide and Pegylated Liposomal Doxorubicin in Combination, Versus Pegylated Liposomal Doxorubicin Alone, in Platinum-Resistant Ovarian Cancer: Exploratory Analysis of the Phase II PRECEDENT Trial.

    Science.gov (United States)

    Herzog, Thomas J; Kutarska, Elżbieta; Bidzińsk, Mariusz; Symanowski, Jim; Nguyen, Binh; Rangwala, Reshma A; Naumann, R Wendel

    2016-11-01

    This exploratory analysis evaluated the incidence of adverse events (AEs) by folate receptor (FR) status in the randomized, multicenter, open-label PRECEDENT study in women with platinum-resistant ovarian cancer receiving pegylated liposomal doxorubicin (PLD) ± the small-molecule drug conjugate vintafolide. Women 18 years or older with platinum-resistant ovarian cancer were randomized 2:1 to vintafolide (2.5 mg intravenously, 3 times per week, weeks 1 and 3, every 28 days) + PLD (50 mg/m intravenously, day 1, every 28 days) or PLD alone (same dose/schedule). The expression of functionally active FR was evaluated by single-photon emission computed tomography with etarfolatide. Patients were categorized according to FR positivity: patients with all target lesions positive for FR expression (FR 100%), patients with 1 or more but not all target lesions positive for FR expression (FR 10%-90%), and patients with all lesions negative for FR expression (FR 0%). Data on FR status were available for 94 patients: 38 were FR 100%, 36 were FR 10% to 90%, and 20 were FR 0%. Across all FR subgroups, the duration of treatment was longer, and the number of cycles was higher in combination-therapy arms than PLD-alone arms. Although the frequency of AEs was relatively consistent across subgroups, the FR 100% subgroup had a higher incidence of patients with at least 1 AE for combination therapy versus PLD alone. No surprising safety signals were shown according to FR status. The incidence of grade 3 or 4 treatment-emergent drug-related AEs was generally low across all FR subgroups and treatment arms. This exploratory analysis suggests that FR status does not influence the AE profile of vintafolide + PLD combination therapy or PLD alone in patients with platinum-resistant ovarian cancer. Future a priori analyses in larger populations are needed to confirm these findings.

  13. Small-molecule synthetic compound norcantharidin reverses multi-drug resistance by regulating Sonic hedgehog signaling in human breast cancer cells.

    Directory of Open Access Journals (Sweden)

    Yu-Jen Chen

    Full Text Available Multi-drug resistance (MDR, an unfavorable factor compromising treatment efficacy of anticancer drugs, involves upregulated ATP binding cassette (ABC transporters and activated Sonic hedgehog (Shh signaling. By preparing human breast cancer MCF-7 cells resistant to doxorubicin (DOX, we examined the effect and mechanism of norcantharidin (NCTD, a small-molecule synthetic compound, on reversing multidrug resistance. The DOX-prepared MCF-7R cells also possessed resistance to vinorelbine, characteristic of MDR. At suboptimal concentration, NCTD significantly inhibited the viability of DOX-sensitive (MCF-7S and DOX-resistant (MCF-7R cells and reversed the resistance to DOX and vinorelbine. NCTD increased the intracellular accumulation of DOX in MCF-7R cells and suppressed the upregulated the mdr-1 mRNA, P-gp and BCRP protein expression, but not the MRP-1. The role of P-gp was strengthened by partial reversal of the DOX and vinorelbine resistance by cyclosporine A. NCTD treatment suppressed the upregulation of Shh expression and nuclear translocation of Gli-1, a hallmark of Shh signaling activation in the resistant clone. Furthermore, the Shh ligand upregulated the expression of P-gp and attenuated the growth inhibitory effect of NCTD. The knockdown of mdr-1 mRNA had not altered the expression of Shh and Smoothened in both MCF-7S and MCF-7R cells. This indicates that the role of Shh signaling in MDR might be upstream to mdr-1/P-gp, and similar effect was shown in breast cancer MDA-MB-231 and BT-474 cells. This study demonstrated that NCTD may overcome multidrug resistance through inhibiting Shh signaling and expression of its downstream mdr-1/P-gp expression in human breast cancer cells.

  14. Resistive MHD Stability Studies of Reversed-Field Pinch

    Energy Technology Data Exchange (ETDEWEB)

    Liu, D.H.

    1996-11-01

    Resistive MHD stability studies of RFPs for various {mu} profiles and pressure profiles have been made. For the first time, a system which can simulate both the experimental hollow {mu} profiles and the locally flattened {mu} profiles has ben set up, thus enabling the extensive stability studies of equilibrium profiles. A {mu} profile locally flattened around the reversal surface is found to deteriorate the internal mode and the m=0 mode. It also expands the corresponding spectra of unstable modes. These may be associated with the increasing magnetic fluctuations. Broadening the {mu} profile is beneficial to stabilizing the internal modes. When a {mu} profile is hollow near the magnetic surface, the spectrum shrinks to low k{sub z} values and the field-reversal is deepened. Whether this hollow {mu} profile deteriorates RFP stability depends on its depth of hollowness and the pinch parameter. Furthermore, unstable modes in RFP are found to be very sensitive to the pressure gradient at the rational surface. Even for the typical {beta}{sub p}=0.1 case, the shaping of the pressure profile dramatically changes the stability of both the plasma core and the plasma boundary regions. These may cast doubt on the `free-force` assumption which is widely used in RFP simulations. 23 refs.

  15. Oridonin induces apoptosis and reverses drug resistance in cisplatin resistant human gastric cancer cells

    Science.gov (United States)

    He, Zhongwei; Xiao, Xiangling; Li, Shan; Guo, Yang; Huang, Qiuyue; Shi, Xin; Wang, Xiaobo; Liu, Ying

    2017-01-01

    Gastric cancer is the third most frequent cause of cancer-associated mortality and almost all patients who respond initially to cisplatin (DDP) later develop drug resistance, indicating multi-drug resistance (MDR) is an essential aspect of the failure of treatment. The natural diterpenoid component Oridonin (Ori) has exhibited efficient inhibition in several types of human cancer. However, the effect and potential mechanism of Ori-reversed MDR in human gastric cancer has not been fully elucidated. In the present study, it was found that Ori significantly suppressed DDP-resistant human SGC7901/DDP cell proliferation, growth and colony formation, causing increased caspase-dependent apoptosis, decreased expression of P-glycoprotein (P-gp), encoded by the MDR gene, multi-drug resistance-associated protein (MRP1), and cyclin D1. SGC7901/DDP cells were cultured with different groups of drugs (Ori, DDP alone, or the combination of Ori and DDP). The drug sensitivity, cell apoptosis and effects on MDR were detected by MTT assay and western blot analysis. The results revealed that Ori is able to reverse the DDP resistance and has a clear synergistic effect with DDP in SGC7901/DDP cells by decreasing the levels of P-gp, MRP1, cyclin D1 and cancerous inhibitor of protein phosphatase 2A. Thus, Ori may be a novel effective candidate to treat DDP-resistant human gastric cancer cells. PMID:28781688

  16. Doxorubicin in TAT peptide-modified multifunctional immunoliposomes demonstrates increased activity against both drug-sensitive and drug-resistant ovarian cancer models

    Science.gov (United States)

    Apte, Anjali; Koren, Erez; Koshkaryev, Alexander; Torchilin, Vladimir P

    2014-01-01

    Multidrug resistance (MDR) is a hallmark of cancer cells and a crucial factor in chemotherapy failure, cancer reappearance, and patient deterioration. We have previously described the physicochemical characteristics and the in vitro anticancer properties of a multifunctional doxorubicin-loaded liposomal formulation. Lipodox®, a commercially available PEGylated liposomal doxorubicin, was made multifunctional by surface-decorating with a cell-penetrating peptide, TATp, conjugated to PEG1000-PE, to enhance liposomal cell uptake. A pH-sensitive polymer, PEG2000-Hz-PE, with a pH-sensitive hydrazone (Hz) bond to shield the peptide in the body and expose it only at the acidic tumor cell surface, was used as well. In addition, an anti-nucleosome monoclonal antibody 2C5 attached to a long-chain polymer to target nucleosomes overexpressed on the tumor cell surface was also present. Here, we report the in vitro cell uptake and cytotoxicity of the modified multifunctional immunoliposomes as well as the in vivo studies on tumor xenografts developed subcutaneously in nude mice with MDR and drug-sensitive human ovarian cancer cells (SKOV-3). Our results show the ability of multifunctional immunoliposomes to overcome MDR by enhancing cytotoxicity in drug-resistant cells, compared with non-modified liposomes. Furthermore, in comparison with the non-modified liposomes, upon intravenous injection of these multifunctional immunoliposomes into mice with tumor xenografts, a significant reduction in tumor growth and enhanced therapeutic efficacy of the drug in both drug-resistant and drug-sensitive mice was obtained. The use of “smart” multifunctional delivery systems may provide the basis for an effective strategy to develop, improve, and overcome MDR cancers in the future. PMID:24145298

  17. The Effects of Selected Sesquiterpenes from Myrica rubra Essential Oil on the Efficacy of Doxorubicin in Sensitive and Resistant Cancer Cell Lines

    Directory of Open Access Journals (Sweden)

    Martin Ambrož

    2017-06-01

    Full Text Available β-caryophyllene oxide (CAO, α-humulene (HUM, trans-nerolidol (NER and valencene (VAL are constituents of the essential oil of Myrica rubra (MEO, which has significant antiproliferative effect in various cancer cell lines. In the present study, we compared the antiproliferative effect of these sesquiterpenes alone and in combination with the cytostatic drug doxorubicin (DOX in cancer cell lines with different sensitivity to DOX. Two ovarian cancer cell lines (sensitive A2780 and partly resistant SKOV3 and two lymphoblast cancer cell lines (sensitive CCRF/CEM and completely resistant CEM/ADR were used. The observed effects varied among sesquiterpenes and also differed in individual cell lines, with only VAL being effective in all the cell lines. A strong synergism of DOX with NER was found in the A2780 cells, while DOX acted synergistically with HUM and CAO in the SKOV3 cells. In the CCRF/CEM cells, a synergism of DOX with CAO and NER was observed. In resistant CEM/ADR cells, sesquiterpenes did not increase DOX efficacy, although they significantly increased accumulation of DOX (up to 10-times and rhodamine-123 (substrate of efflux transporter ABCB1 within cancer cells. In conclusion, the tested sesquiterpenes were able to improve DOX efficacy in the sensitive and partly resistant cancer cells, but not in cells completely resistant to DOX.

  18. Doxorubicin Conjugated to Immunomodulatory Anticancer Lactoferrin Displays Improved Cytotoxicity Overcoming Prostate Cancer Chemo resistance and Inhibits Tumour Development in TRAMP Mice.

    Science.gov (United States)

    Shankaranarayanan, Jayanth Suryanarayanan; Kanwar, Jagat R; Al-Juhaishi, Afrah Jalil Abd; Kanwar, Rupinder K

    2016-08-31

    Advanced, metastatic, castration resistant and chemo-resistant prostate cancer has triggered change in the drug development landscape against prostate cancer. Bovine lactoferrin (bLf) is currently attracting attention in clinics for its anti-cancer properties and proven safety profile. bLf internalises into cancer cells via receptor mediated endocytosis, boosts immunity and complements chemotherapy. We employed bLf as an excellent functional carrier protein for delivering doxorubicin (Dox) into DU145 cells, CD44+/EpCAM+ double positive enriched DU145 3D prostaspheres and drug resistant ADR1000-DU145 cells, thus circumventing Dox efflux, to overcome chemo-resistance. Successful bLf-Dox conjugation with iron free or iron saturated bLf forms did not affect the integrity and functionality of bLf and Dox. bLf-Dox internalised into DU145 cells within 6 h, enhanced nuclear Dox retention up to 24 h, and proved significantly effective (p resistance.

  19. Smoothened antagonists reverse taxane resistance in ovarian cancer.

    Science.gov (United States)

    Steg, Adam D; Katre, Ashwini A; Bevis, Kerri S; Ziebarth, Angela; Dobbin, Zachary C; Shah, Monjri M; Alvarez, Ronald D; Landen, Charles N

    2012-07-01

    The hedgehog pathway has been implicated in the formation and maintenance of a variety of malignancies, including ovarian cancer; however, it is unknown whether hedgehog signaling is involved in ovarian cancer chemoresistance. The goal of this study was to determine the effects of antagonizing the hedgehog receptor, Smoothened (Smo), on chemotherapy response in ovarian cancer. Expression of hedgehog pathway members was assessed in three pairs of parental and chemotherapy-resistant ovarian cancer cell lines (A2780ip2/A2780cp20, SKOV3ip1/SKOV3TRip2, HeyA8/HeyA8MDR) using quantitative PCR and Western blot analysis. Cell lines were exposed to increasing concentrations of two different Smo antagonists (cyclopamine, LDE225) alone and in combination with carboplatin or paclitaxel. Selective knockdown of Smo, Gli1, or Gli2 was achieved using siRNA constructs. Cell viability was assessed by MTT assay. A2780cp20 and SKOV3TRip2 orthotopic xenografts were treated with vehicle, LDE225, paclitaxel, or combination therapy. Chemoresistant cell lines showed higher expression (>2-fold, P < 0.05) of hedgehog signaling components compared with their respective parental lines. Smo antagonists sensitized chemotherapy-resistant cell lines to paclitaxel, but not to carboplatin. LDE225 treatment also increased sensitivity of ALDH-positive cells to paclitaxel. A2780cp20 and SKOV3TRip2 xenografts treated with combined LDE225 and paclitaxel had significantly less tumor burden than those treated with vehicle or either agent alone. Increased taxane sensitivity seems to be mediated by a decrease in P-glycoprotein (MDR1) expression. Selective knockdown of Smo, Gli1, or Gli2 all increased taxane sensitivity. Smo antagonists reverse taxane resistance in chemoresistant ovarian cancer models, suggesting combined anti-hedgehog and chemotherapies could provide a useful therapeutic strategy for ovarian cancer. ©2012 AACR.

  20. PEGylated lipid bilayer-wrapped nano-graphene oxides for synergistic co-delivery of doxorubicin and rapamycin to prevent drug resistance in cancers

    Science.gov (United States)

    Thapa, Raj Kumar; Byeon, Jeong Hoon; Choi, Han-Gon; Yong, Chul Soon; Kim, Jong Oh

    2017-07-01

    Nano-graphene oxide (nGO) is a carbon allotrope studied for its potential as carrier for chemotherapeutic delivery and its photoablation effects. However, interaction of nGO with blood components and the subsequent toxicities warrant a hybrid system for effective cancer drug delivery. Combination chemotherapy aids in effective cancer treatment and prevention of drug resistance. Therefore, in this study, we attempted to prepare polyethylene glycosylated (PEGylated) lipid bilayer-wrapped nGO co-loaded with doxorubicin (DOX) and rapamycin (RAPA), GOLDR, for the prevention and treatment of resistant cancers. Our results revealed a stable GOLDR formulation with appropriate particle size (∼170 nm), polydispersity (∼0.19) and drug loading. Free drug combination (DOX and RAPA) presented synergistic anticancer effects in MDA-MB-231, MCF-7, and BT474 cells. Treatment with GOLDR formulation maintained this synergism in treated cancer cells, which was further enhanced by the near infrared (NIR) laser irradiation-induced photothermal effects of nGO. Higher chromatin condensation and apoptotic body formation, and enhanced protein expression of apoptosis-related markers (Bax, p53, p21, and c-caspase 3) following GOLDR treatment in the presence of NIR laser treatment clearly suggests its superiority in effective chemo-photothermal therapy of resistant cancers. The hybrid nanosystem that we developed provides a basis for the effective use of GOLDR treatment in the prevention and treatment of resistant cancer types.

  1. The radio-sensitizing effect of xanthohumol is mediated by STAT3 and EGFR suppression in doxorubicin-resistant MCF-7 human breast cancer cells.

    Science.gov (United States)

    Kang, Youra; Park, Min A; Heo, Se-Woong; Park, Su-Young; Kang, Keon Wook; Park, Pil-Hoon; Kim, Jung-Ae

    2013-03-01

    Chemotherapeutic drug resistance remains a clinical obstacle in cancer management. Drug-resistant cancer cells usually exhibit cross-resistance to ionizing radiation, which has devastating consequences for patients. With a better understanding of the molecular mechanisms, it will be possible to develop strategies to overcome this cross-resistance and to increase therapeutic sensitivity. Natural and synthetic flavonoid compounds including xanthohumol, the principal flavonoid in hops, were investigated for its radio-sensitizing activity on human breast cancer MCF-7 and adriamycin-resistant MCF-7 (MCF-7/ADR) cells. Chemo-sensitizing or radio-sensitizing effect was analyzed by tetrazolium-based colorimetric assay and flow cytometry. Western blot analysis, confocal microscopy, gene silencing with siRNA transfection and luciferase reporter gene assay were performed to examine signaling molecule activation. Among the tested flavonoid compounds, pretreatment of the cells with xanthohumol significantly sensitized MCF-7/ADR cells to the radiation treatment by inducing apoptosis. In MCF-7/ADR cells, treatment with xanthohumol alone or with gamma-rays significantly decreased levels of anti-apoptotic proteins. Multi-drug resistance 1 (MDR1), epidermal growth factor receptor (EGFR) and signal transducer and activator of transcription 3 (STAT3) expression levels in MCF-7/ADR cells were suppressed by xanthohumol treatment. In addition, xanthohumol treatment increased death receptor (DR)-4 and DR5 expression. The xanthohumol-induced changes of these resistance-related molecules in MCF-7/ADR cells were synergistically increased by gamma-ray treatment. Xanthohumol restored sensitivity of MCF-7/ADR cells to doxorubicin and radiation therapies. Our results suggest that xanthohumol may be a potent chemo- and radio-sensitizer, and its actions are mediated through STAT3 and EGFR inhibition.

  2. Novel acrylonitrile derivatives, YHO-13177 and YHO-13351, reverse BCRP/ABCG2-mediated drug resistance in vitro and in vivo.

    Science.gov (United States)

    Yamazaki, Ryuta; Nishiyama, Yukiko; Furuta, Tomio; Hatano, Hiroshi; Igarashi, Yoshiaki; Asakawa, Naoyuki; Kodaira, Hiroshi; Takahashi, Hiroyuki; Aiyama, Ritsuo; Matsuzaki, Takeshi; Yagi, Nao; Sugimoto, Yoshikazu

    2011-07-01

    Breast cancer resistance protein (BCRP/ABCG2) confers resistance to anticancer drugs such as 7-ethyl-10-hydroxycamptothecin (SN-38, an active metabolite of irinotecan), mitoxantrone, and topotecan. In this study, we examined the reversing effects of YHO-13177, a novel acrylonitrile derivative, and its water-soluble diethylaminoacetate prodrug YHO-13351 on the BCRP-mediated drug resistance. YHO-13177 potentiated the cytotoxicity of SN-38, mitoxantrone, and topotecan in both BCRP-transduced human colon cancer HCT116 (HCT116/BCRP) cells and SN-38-resistant human lung cancer A549 (A549/SN4) cells that express BCRP, but had little effect in the parental cells. In addition, YHO-13177 potentiated the cytotoxicity of SN-38 in human lung cancer NCI-H460 and NCI-H23, myeloma RPMI-8226, and pancreatic cancer AsPC-1 cells that intrinsically expressed BCRP. In contrast, it had no effect on P-glycoprotein-mediated paclitaxel resistance in MDR1-transduced human leukemia K562 cells and multidrug resistance-related protein 1-mediated doxorubicin resistance in MRP1-transfected human epidermoid cancer KB-3-1 cells. YHO-13177 increased the intracellular accumulation of Hoechst 33342, a substrate of BCRP, at 30 minutes and partially suppressed the expression of BCRP protein at more than 24 hours after its treatment in both HCT116/BCRP and A549/SN4 cells. In mice, YHO-13351 was rapidly converted into YHO-13177 after its oral or intravenous administration. Coadministration of irinotecan with YHO-13351 significantly increased the survival time of mice inoculated with BCRP-transduced murine leukemia P388 cells and suppressed the tumor growth in an HCT116/BCRP xenograft model, whereas irinotecan alone had little effect in these tumor models. These findings suggest that YHO-13351, a prodrug of YHO-13177, could be clinically useful for reversing BCRP-mediated drug resistance in cancer chemotherapy. © 2011 American Association for Cancer Research.

  3. Loss of MYC confers resistance to doxorubicin-induced apoptosis by preventing the activation of multiple serine protease- and caspase-mediated pathways

    DEFF Research Database (Denmark)

    Grassilli, Emanuela; Ballabeni, Andrea; Maellaro, Emilia

    2004-01-01

    -MYC null cells we confirm and extend recent reports showing a c-Myc requirement for the induction of apoptosis by a number of anticancer agents. In particular, we show that c-Myc is required for the induction of apoptosis by doxorubicin and etoposide, whereas it is not required for camptothecin......-induced cell death. We have investigated the molecular mechanisms involved in executing doxorubicin-induced apoptosis and show caspase-3 activation by both mitochondria-dependent and -independent pathways. Moreover, serine proteases participate in doxorubicin-induced apoptosis partly by contributing to caspase......-3 activation. Finally, a complete rescue from doxorubicin-induced apoptosis is obtained only when serine proteases, caspase-3, and mitochondrial activation are inhibited simultaneously. Interestingly, doxorubicin requires c-Myc for the activation of all of these pathways. Our findings therefore...

  4. Polarity-dependent reversible resistance switching in Ge-Sb-Te phase-change thin films

    NARCIS (Netherlands)

    Pandian, Ramanathaswamy; Kooi, Bart J.; Palasantzas, George; De Hosson, Jeff T. M.; Pauza, Andrew

    2007-01-01

    In this paper, we demonstrate reversible resistance switching in a capacitorlike cell using a Ge-Sb-Te film that does not rely on amorphous-crystalline phase change. The polarity of the applied electric field switches the cell resistance between lower- and higher-resistance states, as was observed

  5. Phytoestrogens/flavonoids reverse breast cancer resistance protein/ABCG2-mediated multidrug resistance.

    Science.gov (United States)

    Imai, Yasuo; Tsukahara, Satomi; Asada, Sakiyo; Sugimoto, Yoshikazu

    2004-06-15

    Breast cancer resistance protein (BCRP), also called ABCG2, confers resistance to anticancer agents such as 7-ethyl-10-hydroxycamptothecin (SN-38), mitoxantrone, and topotecan. We found previously that sulfated estrogens are physiologic substrates of BCRP. Flavonoids with weak estrogenic activities are called phytoestrogens. In this study, we show that phytoestrogens/flavonoids, such as genistein, naringenin, acacetin, and kaempferol, potentiated the cytotoxicity of SN-38 and mitoxantrone in BCRP-transduced K562 (K562/BCRP) cells. Some glycosylated flavonoids, such as naringenin-7-glucoside, also effectively inhibited BCRP. These flavonoids showed marginal effect on the drug sensitivity of K562 cells. Genistein and naringenin reversed neither P-glycoprotein-mediated vincristine resistance nor multidrug resistance-related protein 1-mediated VP-16 resistance. Genistein and naringenin increased cellular accumulation of topotecan in K562/BCRP cells. K562/BCRP cells also accumulated less [(3)H]genistein than K562 cells. [(3)H]genistein transport in the basal-to-apical direction was greater in BCRP-transduced LLC-PK1 (LLC/BCRP) cells, which express exogenous BCRP in the apical membrane, than in parental cells. Fumitremorgin C abolished the increased transport of [(3)H]genistein in LLC/BCRP cells compared with parental cells. TLC analysis revealed that genistein was transported in its native form but not in its metabolized form. These results suggest that genistein is among the natural substrates of BCRP and competitively inhibits BCRP-mediated drug efflux. The results have two important clinical implications: (a) flavonoids and glycosylated flavonoids may be useful in overcoming BCRP-mediated drug resistance in tumor cells; and (b) coadministration of flavonoids with BCRP-substrate antitumor agents may alter the pharmacokinetics and consequently increase the toxicity of specific antitumor agents in cancer patients.

  6. 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

    Directory of Open Access Journals (Sweden)

    Efferth Thomas

    2006-11-01

    Full Text Available Abstract Background 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. Methods 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. Results 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. Conclusion Based on our studies, we conclude that CuNG may be a promising candidate to sensitize drug resistant cancers in the clinic.

  7. Synthesis of novel 1,8-acridinediones derivatives: Investigation of MDR reversibility on breast cancer cell lines T47D and tamoxifen-resistant T47D.

    Science.gov (United States)

    Moallem, S A; Dehghani, N; Mehri, S; Shahsavand, Sh; Alibolandi, M; Hadizadeh, F

    2015-01-01

    Multi drug resistance (MDR) is a serious obstacle in the management of breast cancer. Therefore, overcoming MDR using novel anticancer agents is a top priority for medicinal chemists. It was found that dihydropyridines lacking calcium antagonistic activity (e.g acridinediones) possess MDR modifier potency. In this study, the capability of four novel acridine-1,8-diones derivatives 3a-d were evaluated as MDR reversing agents. In addition, the relationship between structural properties and biological effects of synthesized compounds was discussed. In vitro cytotoxicity of acridine-1,8-diones 3a-d derivatives in combination with doxorubicin (DOX) on T47D and tomoxifen-resistant T47D (TAMR-6) breast cancer cell lines were investigated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test. Drug resistant index (DRI), which is equal to the ratio of IC50 in drug-resistant cells over IC50 in drug-sensitive cells, was calculated for each substance. Flowcytometry experiments were also implemented to distinguish cells undergoing apoptosis from those undergoing necrosis. The results from MTT and flowcytometry experiments indicated that 1 nM 3c derivative along with DOX significantly (PMDR breast cancer therapy in combination with routine chemotherapeutic agents such as DOX.

  8. Phase 2 study of canfosfamide in combination with pegylated liposomal doxorubicin in platinum and paclitaxel refractory or resistant epithelial ovarian cancer

    Directory of Open Access Journals (Sweden)

    Moore Carla L

    2010-03-01

    Full Text Available Abstract Background Canfosfamide is a novel glutathione analog activated by glutathione S-transferase P1-1. This study evaluated the safety and efficacy of canfosfamide in combination with pegylated liposomal doxorubicin (PLD in patients with platinum resistant ovarian cancer. Patients with platinum resistant ovarian carcinoma and measurable disease received canfosfamide at 960 mg/m2 in combination with PLD at 50 mg/m2, intravenously day 1 in every 28 day cycles until tumor progression or unacceptable toxicities. The primary endpoints were objective response rate (ORR and progression-free survival (PFS. Results Canfosfamide plus PLD combination therapy was administered at 960/50 mg/m2, respectively. Thirty-nine patients received a median number of 4 cycles (range 1.0-18.0. The ORR was 27.8% (95% CI, 14.2-45.2 with a disease stabilization rate of 80.6% (95% CI, 64.0-91.8 in the evaluable population. The CA-125 marker responses correlated with the radiological findings of complete response or partial response. The median PFS was 6.0 months (95% CI, 4.2-7.9 and median survival was 17.8 months. The combination was well tolerated. Myelosuppression was managed with dose reductions and growth factor support. Grade 3 febrile neutropenia was observed in 2 patients (5.1%. Non-hematologic adverse events occurred at the expected frequency and grade for each drug alone, with no unexpected or cumulative toxicities. Conclusions Canfosfamide in combination with PLD is well tolerated and active in platinum and paclitaxel refractory or resistant ovarian cancer. A randomized phase 3 study was conducted based on this supportive phase 2 study. Trial Registration This study was registered at www.clinicaltrials.gov: NCT00052065.

  9. Amurensin G, a potent natural SIRT1 inhibitor, rescues doxorubicin responsiveness via down-regulation of multidrug resistance 1

    DEFF Research Database (Denmark)

    Oh, Won Keun; Cho, Kyoung Bin; Hien, Tran Thi

    2010-01-01

    The transition from a chemotherapy-responsive cancer to a chemotherapy-resistant one is accompanied by increased expression of multidrug resistance 1 (MDR1, p-glycoprotein), which plays an important role in the efflux from the target cell of many anticancer agents. We recently showed that a Forkh...

  10. PRECEDENT: a randomized phase II trial comparing vintafolide (EC145) and pegylated liposomal doxorubicin (PLD) in combination versus PLD alone in patients with platinum-resistant ovarian cancer.

    Science.gov (United States)

    Naumann, R Wendel; Coleman, Robert L; Burger, Robert A; Sausville, Edward A; Kutarska, Elzbieta; Ghamande, Sharad A; Gabrail, Nashat Y; Depasquale, Stephen E; Nowara, Elzbieta; Gilbert, Lucy; Gersh, Robert H; Teneriello, Michael G; Harb, Wael A; Konstantinopoulos, Panagiotis A; Penson, Richard T; Symanowski, James T; Lovejoy, Chandra D; Leamon, Christopher P; Morgenstern, David E; Messmann, Richard A

    2013-12-10

    Vintafolide (EC145) is a folic acid-desacetylvinblastine conjugate that binds to the folate receptor (FR), which is expressed on the majority of epithelial ovarian cancers. This randomized phase II trial evaluated vintafolide combined with pegylated liposomal doxorubicin (PLD) compared with PLD alone. The utility of an FR-targeted imaging agent, (99m)Tc-etarfolatide (EC20), in selecting patients likely to benefit from vintafolide was also examined. Women with recurrent platinum-resistant ovarian cancer who had undergone ≤ two prior cytotoxic regimens were randomly assigned at a 2:1 ratio to PLD (50 mg/m(2) intravenously [IV] once every 28 days) with or without vintafolide (2.5 mg IV three times per week during weeks 1 and 3). Etarfolatide scanning was optional. The primary objective was to compare progression-free survival (PFS) between the groups. The intent-to-treat population comprised 149 patients. Median PFS was 5.0 and 2.7 months for the vintafolide plus PLD and PLD-alone arms, respectively (hazard ratio [HR], 0.63; 95% CI, 0.41 to 0.96; P = .031). The greatest benefit was observed in patients with 100% of lesions positive for FR, with median PFS of 5.5 compared with 1.5 months for PLD alone (HR, 0.38; 95% CI, 0.17 to 0.85; P = .013). The group of patients with FR-positive disease (10% to 90%) experienced some PFS improvement (HR, 0.873), whereas patients with disease that did not express FR experienced no PFS benefit (HR, 1.806). Vintafolide plus PLD is the first combination to demonstrate an improvement over standard therapy in a randomized trial of patients with platinum-resistant ovarian cancer. Etarfolatide can identify patients likely to benefit from vintafolide.

  11. A phase II study of irinotecan and pegylated liposomal doxorubicin in platinum-resistant recurrent ovarian cancer (Tohoku Gynecologic Cancer Unit 104 study).

    Science.gov (United States)

    Shoji, Tadahiro; Takatori, Eriko; Omi, Hideo; Kagabu, Masahiro; Honda, Tatsuya; Futagami, Masayuki; Yokoyama, Yoshihito; Kaiho, Michiko; Tokunaga, Hideki; Otsuki, Takeo; Takano, Tadao; Yaegashi, Nobuo; Kojimahara, Takanobu; Ohta, Tsuyoshi; Nagase, Satoru; Soeda, Shu; Watanebe, Takafumi; Nishiyama, Hiroshi; Sugiyama, Toru

    2017-08-01

    We report a phase II clinical study of the combination of irinotecan (CPT-11) and pegylated liposomal doxorubicin (PLD) in platinum- and taxane-resistant recurrent ovarian cancer, based on the recommended doses determined in a phase I trial. PLD was administered intravenously at a dose of 30 mg/m(2) on day 3. CPT-11 was administered intravenously at a dose of 80 mg/m(2) on days 1 and 15, according to the recommendations of the phase I study. A single course of chemotherapy lasted 28 days, and patients underwent at least 2 courses until disease progression. The primary endpoint was antitumor efficacy, and the secondary endpoints were adverse events, progression-free survival (PFS), and overall survival (OS). The response rate was 32.3% and the disease control rate was 64.5%. Grade 3 and 4 neutropenia, anemia, and a decrease in platelet count were observed in 17 (54.9%), 3 (9.7%), and 1 patient (3.2%), respectively. In terms of grade 3 or higher non-hematologic toxicities, grade 3 nausea occurred in 1 patient (3.2%), vomiting in 3 patients (9.7%), and grade 3 diarrhea and fatigue in 1 patient (3.2%). The median PFS and OS rates were 2 months and not reached, respectively. Of the 11 patients with a treatment-free interval (TFI) of ≥3 months, the response rate was 63.3%, and the median PFS was 7 months. The treatment outcomes for the 31 patients enrolled in this study were unsatisfactory. However, sub-analysis suggested that patients with a TFI of ≥3 months had a good response rate and PFS. This suggests that CPT-11/PLD combination therapy may be a chemotherapy option for platinum-resistant recurrent ovarian cancer.

  12. Prevalence of Primary HIV Drug Resistance in Thailand Detected by Short Reverse Transcriptase Genotypic Resistance Assay.

    Science.gov (United States)

    Kiertiburanakul, Sasisopin; Pinsai, Subencha; Chantratita, Wasun; Pasomsub, Ekawat; Leechawengwongs, Manoon; Thipmontree, Wilawan; Siriyakorn, Nirada; Sungkanuparph, Somnuek

    2016-01-01

    HIV drug resistance (HIVDR) is the major cause of treatment failure after scaling up of antiretroviral therapy (ART). HIVDR testing prior to ART initiation is not routinely performed in resource-limited settings. We aimed to assess the prevalence of primary HIVDR by short reverse transcriptase (RT) genotypic resistance assay and evaluate of the impact of the mutations on the treatment outcomes. A prospective cohort study was conducted in treatment-naïve HIV-infected patients. Fourteen major mutations of codon 99-191 on the RT gene were selected (K103N, V106A/M, V108I, Q151M, Y181C/I, M184V/I, Y188C/L/H, and G190S/A) at a cost of testing of 35 USD. The association between the presence of primary HIVDR and undetectable HIV RNA (logistic regression, factors associated with undetectable HIV RNA after 6 months of ART were: having M184V/I (odds ratio [OR] 0.11; 95% confidence interval [CI] 0.02-0.62, p = 0.013), condom use (OR 2.38; 95% CI 1.12-5.06, p = 0.024), and adherence per 5% increase (OR 1.16; 95% CI 1.00-1.35, p = 0.044). The prevalence of primary HIVDR is approximately 8%; it is associated with detectable HIV RNA at 6 months after ART initiation. Routine "short RT" genotypic resistance assay should be considered in resource-limited settings to maximize treatment outcome.

  13. Long-term effect of pegylated liposomal doxorubicin in recurrent platinum-resistant ovarian cancer: а clinical case

    Directory of Open Access Journals (Sweden)

    I. A. Pokataev

    2015-01-01

    Full Text Available Despite the high initial susceptibility of ovarian cancer (OC to chemotherapy, the vast majority of patients with Stages III–IV of the disease have its recurrences. Chemotherapy is a main treatment for recurrent OC. In Russia, the rate of platinum-resistant recurrences after first-line chemotherapy is more than 50 %, which may be due to the high extent of a tumor process at the moment of diagnosis, to the low rate of optimal cytoreductive interventions, and to non-optimal treatment. Many oncologists refuse to treat patients with recurrent platinum-resistant OC since the existing Russian and foreign guidelines point to the low efficiency of current chemotherapy for this type of recurrences. At the same time, whether chemotherapy should be used to treat platinum-resistant recurrences must be decided by taking into account a set of clinical factors that along with the duration of a platinum-free interval are also predictors for the efficiency of chemotherapy. These predictors should include mainly the histological pattern of a tumor; an immediate response to previous lines of chemotherapy; the number of previously used anticancer drugs; a patient’s general condition; and her existing factors that can influence the tolerability of chemotherapy. This paper describes a clinical case of a long-term survival in an OC patient who has developed a platinum-resistant recurrence just after first-line chemotherapy. Incomplete cross-resistance of the tumor to other drugs when a platinum-resistance recurrence develops, as well as its high susceptibility to the re-use of platinum-resistant derivatives possibly due to the artificial increase of a platinum-free interval should be identified among the factors that have influenced the prediction of treatment in this patient.

  14. A self-assembled polyjuglanin nanoparticle loaded with doxorubicin and anti-Kras siRNA for attenuating multidrug resistance in human lung cancer.

    Science.gov (United States)

    Wen, Zhong-Mei; Jie, Jing; Zhang, Yuan; Liu, Han; Peng, Li-Ping

    2017-12-02

    Lung cancer is a leading cause of cancer-associated mortality worldwide, which has a low survival rate. Multidrug resistance (MDR) is a major obstacle that hinders the treatment of lung cancer. Doxorubicin (DOX) is an anthracycline glycoside antibiotic, having a broad spectrum of anticancer activity against various solid tumors. Juglanin is a natural production, mainly extracted from green walnut husks of Juglans mandshurica, exhibiting various bioactivities. Here, we demonstrated that the combination of drug, gene and nanoparticle overcame MDR, inhibiting lung cancer progression. A novel nanoparticular pre-chemosensitizer was applied to develop a self-assembled nanoparticle formula of amphiphilic poly(juglanin (Jug) dithiodipropionic acid (DA))-b-poly(ethylene glycol) (PEG)-siRNA Kras with DOX in the core (DOX/PJAD-PEG-siRNA). The formed nanoparticles, appeared spherical shape, had mean particle size of 81.8 nm, and the zeta potential was -18.62 mV. The in vitro drug release results suggested that a sustained release was observed in DOX/PJAD-PEG-siRNA nanoparticles compared to the free DOX. Jug could improve the cytotoxicity of DOX to cancer cells with MDR. Oncogene, Kras, was dose-dependently reduced by treatment of DOX/PJAD-PEG-siRNA nanoparticles. Additionally, P-glycoprotein (MDR1) and c-Myc, contributing to tumor progression, were suppressed by the nanoparticles, while p53 was improved in drug-resistant cells. Colony formation analysis suggested that DOX/PJAD-PEG-siRNA nanoparticles showed the most effective role in reducing cancer cell proliferation. In vivo, DOX/PJAD-PEG-siRNA nanoparticles reduced tumor growth compared to the free DOX, accompanied with reduced KI-67 and enhanced TUNEL positive levels in drug-resistant xenografted nude mice. Thus, the findings above indicated that juglanin, as a chemosensitizer, potentiate the anti-cancer role of DOX in drug-resistant cancer cells. And the nanoparticles exhibited stronger antitumor efficiency

  15. Modulation of telomerase and signal transduction proteins by hexyl-ALA-photodynamic therapy (PDT) in human doxorubicin resistant cancer cell models.

    Science.gov (United States)

    Chu, Ellie S M; Yow, Christine M N

    2012-09-01

    This study employed a doxorubicin resistant (MES-SA-Dx5) human uterine sarcoma cell line and its counterpart (MES-SA), to elucidate the efficacy of aminolevulinic acid-hexylester (hexyl-ALA) mediated PDT at molecular and transcriptional levels. Hexyl-ALA generated protoporphyrin IX in both cells were determined by molecular probes using Confocal Laser Scanning Microscopy. The hexyl-ALA-PDT induced signal transduction proteins and mode of cell death were quantitated by CASE ELISA assays and DAPI staining. The modulation of hTERT mRNA expression and telomerase activity were investigated by TaqMan real-time PCR and ELISA respectively. Hexyl-ALA-PDT mediated cell migratory effect was determined by wound-healing assay. The results demonstrated that mitochondria were the major target of hexyl-ALA. At LD(30), hexyl-ALA-PDT significantly provoked an up-regulation of phosphorylated p38MAPK and JNK proteins in both cells. Hexyl-ALA-PDT down-regulated hTERT (a catalytic subunit of telomerase) mRNA expression and showed a strong correlation with diminished telomerase activity in both cells (MES-SA: r(2) = 0.9932; MES-SA-Dx5: r(2) = 0.9775). The suppression of cell migratory effect in both cells was obtained after hexyl-ALA-PDT. Further, 50% and 30% of apoptotic cells were attained at LD(50), for wild-type and drug resistant cells respectively. Unlike the wild-type, a higher PDT dose was crucial to induce apoptosis in the drug resistant cells. Our study provides the first evidence that p38MAPK and JNK kinases played a vital role in triggering hexyl-ALA-PDT-induced apoptosis, down-regulated hTERT mRNA expression and telomerase activity in both proposed cells. In vivo studies are worth examining for the benefit of clinical applications in drug resistant cancers and PDT development. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Targeting Plasmodium falciparum Hsp90: Towards Reversing Antimalarial Resistance

    Directory of Open Access Journals (Sweden)

    Dea Shahinas

    2013-02-01

    Full Text Available Malaria continues to exact a great human toll in tropical settings. Antimalarial resistance is rife and the parasite inexorably develops mechanisms to outwit our best drugs, including the now first-line choice, artesunate. Novel strategies to circumvent resistance are needed. Here we detail drug development focusing on heat shock protein 90 and its central role as a chaperone. A growing body of evidence supports the role for Hsp90 inhibitors as adjunctive drugs able to restore susceptibility to traditionally efficacious compounds like chloroquine.

  17. Oleanolic and maslinic acid sensitize soft tissue sarcoma cells to doxorubicin by inhibiting the multidrug resistance protein MRP-1, but not P-glycoprotein.

    Science.gov (United States)

    Villar, Victor Hugo; Vögler, Oliver; Barceló, Francisca; Gómez-Florit, Manuel; Martínez-Serra, Jordi; Obrador-Hevia, Antònia; Martín-Broto, Javier; Ruiz-Gutiérrez, Valentina; Alemany, Regina

    2014-04-01

    The pentacyclic triterpenes oleanolic acid (OLA) and maslinic acid (MLA) are natural compounds present in many plants and dietary products consumed in the Mediterranean diet (e.g., pomace and virgin olive oils). Several nutraceutical activities have been attributed to OLA and MLA, whose antitumoral effects have been extensively evaluated in human adenocarcinomas, but little is known regarding their effectiveness in soft tissue sarcomas (STS). We assessed efficacy and molecular mechanisms involved in the antiproliferative effects of OLA and MLA as single agents or in combination with doxorubicin (DXR) in human synovial sarcoma SW982 and leiomyosarcoma SK-UT-1 cells. As single compound, MLA (10-100 μM) was more potent than OLA, inhibiting the growth of SW982 and SK-UT-1 cells by 70.3 ± 1.11% and 68.8 ± 1.52% at 80 μM, respectively. Importantly, OLA (80 μM) or MLA (30 μM) enhanced the antitumoral effect of DXR (0.5-10 μM) by up to 2.3-fold. On the molecular level, efflux activity of the multidrug resistance protein MRP-1, but not of the P-glycoprotein, was inhibited. Most probably as a consequence, DXR accumulated in these cells. Kinetic studies showed that OLA behaved as a competitive inhibitor of substrate-mediated MRP-1 transport, whereas MLA acted as a non-competitive one. Moreover, none of both triterpenes induced a compensatory increase in MRP-1 expression. In summary, OLA or MLA sensitized cellular models of STS to DXR and selectively inhibited MRP-1 activity, but not its expression, leading to a higher antitumoral effect possibly relevant for clinical treatment. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Salvage chemotherapy in recurrent platinum-resistant or refractory epithelial ovarian cancer with Carboplatin and distearoylphosphatidylcholine pegylated liposomal Doxorubicin (lipo-dox®).

    Science.gov (United States)

    Khemapech, Nipon; Oranratanaphan, S; Termrungruanglert, W; Lertkhachonsuk, R; Vasurattana, A

    2013-01-01

    To evaluate the efficacy and safety of distearoylphosphatidylcholine pegylated liposomal doxorubicin (DPLD) combined with carboplatin for the treatment of platinum resistant or refractory epithelial ovarian cancer (EOC) or fallopian tube cancer. A retrospective analysis of women who received DPLD with carboplatin for recurrent EOC or fallopian tube cancer in King Chulalongkorn Memorial Hospital Thailand from January 2006 to August 2011 was conducted. Patients were identified from the medical records and data on demographic factors, stage, histology, surgical findings, cytoreduction status, and prior chemotherapies were abstracted. The efficacy and toxicity of DPLD/carboplatin were evaluated. Progression-free (PFS) and overall survival (OS) were estimated by the Kaplan-Meier method. A total of 65 patients, 64 with platinum resistant or refractory epithelial ovarian cancer and 1 with fallopian tube cancer, were enrolled. DPLD and carboplatin were given for an average of 4.46 cycles per patient with a total of 273 cycles. Among the 65 evaluable patients, 0% achieved CR, 7.69% PR, 15.4% SD and 76.% PD. The overall response rate was 23.1%. With a median follow-up of 27.4 months, the median progression-free and median overall survival in the 36 patients was 4.46 months and 8.76 months respectively. In the aspect of side effects, palmar-plantar erythrodysesthesia (PPE) occurred in 33.3% (Grade I 22.2%, Grade II 11.1%) and mucositis in 41.7% (Grade I 27.8%, Grade II 13.9%) of all treatment cycles, all Grade 1 or 2. Anemia, leukopenia and thrombocytopenia occurred in 58.3% (Grade I 41.7%, Grade II 16.7%), 66.7% (Grade I 47.2%, Grade II 19.4%), and 22.2% (Grade I 16.6%, Grade II 5.56%) of cycle respectively, and were mostly Grade 1 or 2. DPLD, the second-generation PLD drug combined with carboplatin every 4 weeks, is effective and has low toxicity for treatment of patients with recurrent platinum-resistant or refractory epithelial ovarian cancer.

  19. Reversing Anoikis Resistance in Triple-Negative Breast Cancer

    Science.gov (United States)

    2015-10-01

    hepatocellular carcinoma after curative resection. Cancer. 2012;118:2708-17. Epub 2011/10/13. 38. Liu JJ, Shen R, Chen L, et al. Piwil2 is expressed ...200c suppresses translation of these transcripts inappropriately expressed by carcinomas to facilitate anoikis resistance AND alters splicing events...induces apoptosis by shuttling proteins to the nucleus. The full-length transcript encodes a tumor suppressor motor protein whose loss of expression has

  20. Panitumumab and pegylated liposomal doxorubicin in platinum-resistant epithelial ovarian cancer with KRAS wild-type

    DEFF Research Database (Denmark)

    Dahl Steffensen, Karina; Waldstrøm, Marianne; Lund, Bente

    , and head and neck cancer. No previous studies have evaluated the effect of panitumumab in OC based on KRAS mutation status. Methods: Eligibility criteria are confirmed stage I-IV primary epithelial ovarian/fallopian/peritoneal cancer patients with progression either during or within 6 months after end...... to a total of 33 patients. At present, 15 patients have been enrolled. The primary endpoint is to investigate the response rate in platinum-resistant, KRAS wild- type OC patients treated with PLD supplemented with panitumumab. Translational research is included as a secondary endpoint and tumor tissue...

  1. Resistance of renal cell carcinoma to sorafenib is mediated by potentially reversible gene expression.

    Directory of Open Access Journals (Sweden)

    Liang Zhang

    Full Text Available PURPOSE: Resistance to antiangiogenic therapy is an important clinical problem. We examined whether resistance occurs at least in part via reversible, physiologic changes in the tumor, or results solely from stable genetic changes in resistant tumor cells. EXPERIMENTAL DESIGN: Mice bearing two human RCC xenografts were treated with sorafenib until they acquired resistance. Resistant 786-O cells were harvested and reimplanted into naïve mice. Mice bearing resistant A498 cells were subjected to a 1 week treatment break. Sorafenib was then again administered to both sets of mice. Tumor growth patterns, gene expression, viability, blood vessel density, and perfusion were serially assessed in treated vs control mice. RESULTS: Despite prior resistance, reimplanted 786-O tumors maintained their ability to stabilize on sorafenib in sequential reimplantation steps. A transcriptome profile of the tumors revealed that the gene expression profile of tumors upon reimplantation reapproximated that of the untreated tumors and was distinct from tumors exhibiting resistance to sorafenib. In A498 tumors, revascularization was noted with resistance and cessation of sorafenib therapy and tumor perfusion was reduced and tumor cell necrosis enhanced with re-exposure to sorafenib. CONCLUSIONS: In two RCC cell lines, resistance to sorafenib appears to be reversible. These results support the hypothesis that resistance to VEGF pathway therapy is not solely the result of a permanent genetic change in the tumor or selection of resistant clones, but rather is due to a great extent to reversible changes that likely occur in the tumor and/or its microenvironment.

  2. Oxidative/Nitrative Stress and Inflammation Drive Progression of Doxorubicin-Induced Renal Fibrosis in Rats as Revealed by Comparing a Normal and a Fibrosis-Resistant Rat Strain.

    Science.gov (United States)

    Szalay, Csaba Imre; Erdélyi, Katalin; Kökény, Gábor; Lajtár, Enikő; Godó, Mária; Révész, Csaba; Kaucsár, Tamás; Kiss, Norbert; Sárközy, Márta; Csont, Tamás; Krenács, Tibor; Szénási, Gábor; Pacher, Pál; Hamar, Péter

    2015-01-01

    Chronic renal fibrosis is the final common pathway of end stage renal disease caused by glomerular or tubular pathologies. Genetic background has a strong influence on the progression of chronic renal fibrosis. We recently found that Rowett black hooded rats were resistant to renal fibrosis. We aimed to investigate the role of sustained inflammation and oxidative/nitrative stress in renal fibrosis progression using this new model. Our previous data suggested the involvement of podocytes, thus we investigated renal fibrosis initiated by doxorubicin-induced (5 mg/kg) podocyte damage. Doxorubicin induced progressive glomerular sclerosis followed by increasing proteinuria and reduced bodyweight gain in fibrosis-sensitive, Charles Dawley rats during an 8-week long observation period. In comparison, the fibrosis-resistant, Rowett black hooded rats had longer survival, milder proteinuria and reduced tubular damage as assessed by neutrophil gelatinase-associated lipocalin (NGAL) excretion, reduced loss of the slit diaphragm protein, nephrin, less glomerulosclerosis, tubulointerstitial fibrosis and matrix deposition assessed by periodic acid-Schiff, Picro-Sirius-red staining and fibronectin immunostaining. Less fibrosis was associated with reduced profibrotic transforming growth factor-beta, (TGF-β1) connective tissue growth factor (CTGF), and collagen type I alpha 1 (COL-1a1) mRNA levels. Milder inflammation demonstrated by histology was confirmed by less monocyte chemotactic protein 1 (MCP-1) mRNA. As a consequence of less inflammation, less oxidative and nitrative stress was obvious by less neutrophil cytosolic factor 1 (p47phox) and NADPH oxidase-2 (p91phox) mRNA. Reduced oxidative enzyme expression was accompanied by less lipid peroxidation as demonstrated by 4-hydroxynonenal (HNE) and less protein nitrosylation demonstrated by nitrotyrosine (NT) immunohistochemistry and quantified by Western blot. Our results demonstrate that mediators of fibrosis, inflammation and

  3. Reversal of resistance to pyriproxyfen in the Q biotype of Bemisia tabaci (Hemiptera: Aleyrodidae).

    Science.gov (United States)

    Wilson, Margaret; Moshitzky, Pnina; Laor, Einat; Ghanim, Murad; Horowitz, A Rami; Morin, Shai

    2007-08-01

    Pyriproxyfen, a juvenile hormone (JH) mimic, is a biorational insecticide that disrupts insect development. It is one of the principal insecticides being used to control Bemisia tabaci (Gennadius) on cotton, and has many environmentally positive attributes that make it compatible with integrated pest management (IPM) programs. In Israel, a high level of resistance to pyriproxyfen has been observed in several isolated regions. Here, tests were conducted to establish whether temporal refuges from exposure to pyriproxyfen could be useful for restoring the effectiveness of the compound. Resistance was found to decrease by a factor of 8 when exposure to pyriproxyfen was ceased for 13 generations. Reversal of resistance was accompanied with increased biotic fitness of the revertant colony. By incorporating experimental estimates of nymph survival, sex ratio, fecundity, egg hatching rate and developmental time, the seasonal cost per generation for resistant insects was estimated to be 25%. A genetic simulation model, optimized by empirical data from bioassays, predicted fitness cost per generation of 19% for resistant homozygous (RR) females and hemizygous (R) males, and produced rates of reversal similar to the experimental results. The model also predicted that, even after 5 years ( approximately 55 generations) without pyriproxyfen treatments, the frequency of the resistance allele (R) will still remain high (0.02). It is therefore concluded, on the basis of experimental and modeling results, that the effectiveness of temporal refuges for reversing development of resistance to pyriproxyfen in B. tabaci may be limited. Copyright (c) 2007 Society of Chemical Industry

  4. X-ray irradiation induced reversible resistance change in Pt/TiO2/Pt cells.

    Science.gov (United States)

    Chang, Seo Hyoung; Kim, Jungho; Phatak, Charudatta; D'Aquila, Kenneth; Kim, Seong Keun; Kim, Jiyoon; Song, Seul Ji; Hwang, Cheol Seong; Eastman, Jeffrey A; Freeland, John W; Hong, Seungbum

    2014-02-25

    The interaction between X-rays and matter is an intriguing topic for both fundamental science and possible applications. In particular, synchrotron-based brilliant X-ray beams have been used as a powerful diagnostic tool to unveil nanoscale phenomena in functional materials. However, it has not been widely investigated how functional materials respond to the brilliant X-rays. Here, we report the X-ray-induced reversible resistance change in 40-nm-thick TiO2 films sandwiched by Pt top and bottom electrodes, and propose the physical mechanism behind the emergent phenomenon. Our findings indicate that there exists a photovoltaic-like effect, which modulates the resistance reversibly by a few orders of magnitude, depending on the intensity of impinging X-rays. We found that this effect, combined with the X-ray irradiation induced phase transition confirmed by transmission electron microscopy, triggers a nonvolatile reversible resistance change. Understanding X-ray-controlled reversible resistance changes can provide possibilities to control initial resistance states of functional materials, which could be useful for future information and energy storage devices.

  5. Glucocorticoid Induced Leucine Zipper inhibits apoptosis of cardiomyocytes by doxorubicin

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar, David; Strom, Joshua; Chen, Qin M., E-mail: qchen@email.arizona.edu

    2014-04-01

    Doxorubicin (Dox) is an indispensable chemotherapeutic agent for the treatment of various forms of neoplasia such as lung, breast, ovarian, and bladder cancers. Cardiotoxicity is a major concern for patients receiving Dox therapy. Previous work from our laboratory indicated that glucocorticoids (GCs) alleviate Dox-induced apoptosis in cardiomyocytes. Here we have found Glucocorticoid-Induced Leucine Zipper (GILZ) to be a mediator of GC-induced cytoprotection. GILZ was found to be induced in cardiomyocytes by GC treatment. Knocking down of GILZ using siRNA resulted in cancelation of GC-induced cytoprotection against apoptosis by Dox treatment. Overexpressing GILZ by transfection was able to protect cells from apoptosis induced by Dox as measured by caspase activation, Annexin V binding and morphologic changes. Western blot analyses indicate that GILZ overexpression prevented cytochrome c release from mitochondria and cleavage of caspase-3. When bcl-2 family proteins were examined, we found that GILZ overexpression causes induction of the pro-survival protein Bcl-xL. Since siRNA against Bcl-xL reverses GC induced cytoprotection, Bcl-xL induction represents an important event in GILZ-induced cytoprotection. Our data suggest that GILZ functions as a cytoprotective gene in cardiomyocytes. - Highlights: • Corticosteroids act as a cytoprotective agent in cardiomyocytes • Corticosteroids induce GILZ expression in cardiomyocytes • Elevated GILZ results in resistance against apoptosis induced by doxorubicin • GILZ induces Bcl-xL protein without inducing Bcl-xL mRNA.

  6. Amiodarone is more efficient than verapamil in reversing resistance to anthracyclines in tumour cells.

    OpenAIRE

    Chauffert, B.; D. Rey; Coudert, B; Dumas, M.; F Martin

    1987-01-01

    We have previously demonstrated that amiodarone is able to reverse resistance of rat colon cancer cells to anthracyclines. We now compare the efficiency of amiodarone to verapamil one, another antiarrhythmic agent used in experimental systems and in clinical trials to enhance the effects of anthracyclines on resistant cancer cells. Amiodarone is more efficient than verapamil when both drugs are used at the same molar concentrations. Desethylamiodarone, the main metabolite of amiodarone, is as...

  7. Reverse evolution: selection against costly resistance in disease-free microcosm populations of Paramecium caudatum.

    Science.gov (United States)

    Duncan, Alison B; Fellous, Simon; Kaltz, Oliver

    2011-12-01

    Evolutionary costs of parasite resistance arise if genes conferring resistance reduce fitness in the absence of parasites. Thus, parasite-mediated selection may lead to increased resistance and a correlated decrease in fitness, whereas relaxed parasite-mediated selection may lead to reverse evolution of increased fitness and a correlated decrease in resistance. We tested this idea in experimental populations of the protozoan Paramecium caudatum and the parasitic bacterium Holospora undulata. After eight years, resistance to infection and asexual reproduction were compared among paramecia from (1) "infected" populations, (2) uninfected "naive" populations, and (3) previously infected, parasite-free "recovered" populations. Paramecia from "infected" populations were more resistant (+12%), but had lower reproduction (-15%) than "naive" paramecia, indicating an evolutionary trade-off between resistance and fitness. Recovered populations showed similar reproduction to naive populations; however, resistance of recently (3 years) recovered populations were as susceptible as naive populations. This suggests a weak, convex trade-off between resistance and fitness, allowing recovery of fitness, without complete loss of resistance, favoring the maintenance of a generalist strategy of intermediate fitness and resistance. Our results indicate that (co)evolution with parasites can leave a genetic signature in disease-free populations. © 2011 The Author(s). Evolution© 2011 The Society for the Study of Evolution.

  8. Exploring Post-Treatment Reversion of Antimicrobial Resistance in Enteric Bacteria of Food Animals as a Resistance Mitigation Strategy.

    Science.gov (United States)

    Volkova, Victoriya V; KuKanich, Butch; Riviere, Jim E

    2016-11-01

    Antimicrobial drug use in food animals is associated with an elevation in relative abundance of bacteria resistant to the drug among the animal enteric bacteria. Some of these bacteria are potential foodborne pathogens. Evidence suggests that at least in the enteric nontype-specific Escherichia coli, after treatment the resistance abundance reverts to the background pre-treatment levels, without further interventions. We hypothesize that it is possible to define the distribution of the time period after treatment within which resistance to the administered drug, and possibly other drugs in case of coselection, in fecal bacteria of the treated animals returns to the background pre-treatment levels. Furthermore, it is possible that a novel resistance mitigation strategy for microbiological food safety could be developed based on this resistance reversion phenomenon. The strategy would be conceptually similar to existing antimicrobial drug withdrawal periods, which is a well-established and accepted mitigation strategy for avoiding violative drug residues in the edible products from the treated animals. For developing resistance-relevant withdrawals, a mathematical framework can be used to join the necessary pharmacological, microbiological, and animal production components to project the distributions of the post-treatment resistance reversion periods in the production animal populations for major antimicrobial drug classes in use. The framework can also help guide design of empirical studies into the resistance-relevant withdrawal periods and development of mitigation approaches to reduce the treatment-associated elevation of resistance in animal enteric bacteria. We outline this framework, schematically and through exemplar equations, and how its components could be formulated.

  9. Biological characteristics of Taxol‑resistant ovarian cancer cells and reversal of Taxol resistance by adenovirus expressing p53.

    Science.gov (United States)

    Liu, Qun; Sui, Rui; Li, Ruirui; Miao, Jinwei; Liu, Jian

    2015-02-01

    The development of acquired drug resistance is the primary cause of chemotherapy failure in the treatment of ovarian cancer. To examine the mechanism underlying Taxol (TAX) resistance in ovarian cancer and attempt to reverse it, the present study induced a TAX‑resistant ovarian cancer cell line SKOV3/TAX using a gradient concentration increment method. The properties of the resistant cell line were initially investigated by proliferation, colony formation, adhesion and cell cycle analysis compared with control SKOV3 cells. To examine the mechanism, the expression of p53 upregulated modulator of apoptosis (PUMA) was compared between SKOV3/TAX and SKOV3 cells by western blot analysis. An adenovirus expressing p53 (Ad‑p53), alone or in combination with TAX, was used to treat the drug‑resistant ovarian cancer cells SKOV3/TAX. The effects of Ad‑p53 on pro‑apoptosis and the reversal of drug resistance were evaluated using flow cytometric analysis, cleaved‑poly ADP‑ribose polymerase detection, microscopic observation and MTT measurement. Compared with the control cells, the TAX‑resistant ovarian cancer cell line SKOV3/TAX was characterized by reduced sensitivity to TAX treatment, a significantly slower proliferation rate, higher colony‑forming efficiency and higher adhesion ability. However, no significant difference in cell cycle distribution was identified. PUMA, a potent pro‑apoptotic protein, was markedly suppressed in the SKOV3/TAX cells. Ad‑p53 infection stimulated the upregulation of PUMA and re‑sensitized the resistant ovarian cancer cells to TAX by an apoptotic mechanism. Therefore, Ad‑p53 infection is an effective gene therapy method to re‑sensitize the resistant ovarian cancer cells to TAX by restoring the expression of PUMA.

  10. Liposomal Coencapsulation of Doxorubicin with Listeriolysin O Increases Potency via Subcellular Targeting.

    Science.gov (United States)

    Walls, Zachary F; Gong, Henry; Wilson, Rebecca J

    2016-03-07

    Liposomal doxorubicin is a clinically important drug formulation indicated for the treatment of several different forms of cancer. For doxorubicin to exert a therapeutic effect, it must gain access to the nucleus. However, a large proportion of the liposomal doxorubicin dose fails to work because it is sequestered within endolysosomal organelles following endocytosis of the liposomes due to the phenomenon of ion trapping. Listeriolysin O (LLO) is a pore-forming protein that can provide a mechanism for endosomal escape. The present study demonstrates that liposomal coencapsulation of doxorubicin with LLO enables a significantly larger percentage of the dose to colocalize with the nucleus compared to liposomes containing doxorubicin alone. The change in intracellular distribution resulted in a significantly more potent formulation of liposomal doxorubicin as demonstrated in both the ovarian carcinoma cell line A2780 and its doxorubicin-resistant derivative A2780ADR.

  11. Amiodarone is more efficient than verapamil in reversing resistance to anthracyclines in tumour cells.

    Science.gov (United States)

    Chauffert, B.; Rey, D.; Coudert, B.; Dumas, M.; Martin, F.

    1987-01-01

    We have previously demonstrated that amiodarone is able to reverse resistance of rat colon cancer cells to anthracyclines. We now compare the efficiency of amiodarone to verapamil one, another antiarrhythmic agent used in experimental systems and in clinical trials to enhance the effects of anthracyclines on resistant cancer cells. Amiodarone is more efficient than verapamil when both drugs are used at the same molar concentrations. Desethylamiodarone, the main metabolite of amiodarone, is as efficient as its precursor. Optimal concentrations of amiodarone are obtained without side effects in the sera of patients treated by oral administration followed by a loading infusion of amiodarone. On the other hand, maximal tolerated levels of verapamil reported in clinical trials are less efficient than amiodarone maximal levels in the reversal of resistance to anthracyclines in our experimental model in vitro. We suggest that amiodarone, which is more efficient and less toxic than verapamil, could be substituted for verapamil in future clinical trials. PMID:3663463

  12. ABC transporters as multidrug resistance mechanisms and the development of chemosensitizers for their reversal

    Directory of Open Access Journals (Sweden)

    Choi Cheol-Hee

    2005-10-01

    Full Text Available Abstract One of the major problems related with anticancer chemotherapy is resistance against anticancer drugs. The ATP-binding cassette (ABC transporters are a family of transporter proteins that are responsible for drug resistance and a low bioavailability of drugs by pumping a variety of drugs out cells at the expense of ATP hydrolysis. One strategy for reversal of the resistance of tumor cells expressing ABC transporters is combined use of anticancer drugs with chemosensitizers. In this review, the physiological functions and structures of ABC transporters, and the development of chemosensitizers are described focusing on well-known proteins including P-glycoprotein, multidrug resistance associated protein, and breast cancer resistance protein.

  13. Antibiotic Resistance Determinant-Focused Acinetobacter baumannii Vaccine Designed Using Reverse Vaccinology.

    Science.gov (United States)

    Ni, Zhaohui; Chen, Yan; Ong, Edison; He, Yongqun

    2017-02-21

    As one of the most influential and troublesome human pathogens, Acinetobacter baumannii (A. baumannii) has emerged with many multidrug-resistant strains. After collecting 33 complete A. baumannii genomes and 84 representative antibiotic resistance determinants, we used the Vaxign reverse vaccinology approach to predict classical type vaccine candidates against A. baumannii infections and new type vaccine candidates against antibiotic resistance. Our genome analysis identified 35 outer membrane or extracellular adhesins that are conserved among all 33 genomes, have no human protein homology, and have less than 2 transmembrane helices. These 35 antigens include 11 TonB dependent receptors, 8 porins, 7 efflux pump proteins, and 2 fimbrial proteins (FilF and CAM87009.1). CAM86003.1 was predicted to be an adhesin outer membrane protein absent from 3 antibiotic-sensitive strains and conserved in 21 antibiotic-resistant strains. Feasible anti-resistance vaccine candidates also include one extracellular protein (QnrA), 3 RND type outer membrane efflux pump proteins, and 3 CTX-M type β-lactamases. Among 39 β-lactamases, A. baumannii CTX-M-2, -5, and -43 enzymes are predicted as adhesins and better vaccine candidates than other β-lactamases to induce preventive immunity and enhance antibiotic treatments. This report represents the first reverse vaccinology study to systematically predict vaccine antigen candidates against antibiotic resistance for a microbial pathogen.

  14. The Role of Nucleotide Excision by Reverse Transcriptase in HIV Drug Resistance

    Directory of Open Access Journals (Sweden)

    Walter A. Scott

    2010-01-01

    Full Text Available Nucleoside reverse transcriptase (RT inhibitors of HIV block viral replication through the ability of HIV RT to incorporate chain-terminating nucleotide analogs during viral DNA synthesis. Once incorporated, the chain-terminating residue must be removed before DNA synthesis can continue. Removal can be accomplished by the excision activity of HIV RT, which catalyzes the transfer of the 3'-terminal residue on the blocked DNA chain to an acceptor substrate, probably ATP in most infected cells. Mutations of RT that enhance excision activity are the most common cause of resistance to 3'-azido-3'-deoxythymidine (AZT and exhibit low-level cross-resistance to most other nucleoside RT inhibitors. The resistance to AZT is suppressed by a number of additional mutations in RT, most of which were identified because they conferred resistance to other RT inhibitors. Here we review current understanding of the biochemical mechanisms responsible for increased or decreased excision activity due to these mutations.

  15. Positional stability of field-reversed-configurations in the presence of resistive walls

    Energy Technology Data Exchange (ETDEWEB)

    Rath, N., E-mail: nrath@trialphanenergy.com; Onofri, M.; Barnes, D. C. [Tri Alpha Energy, P.O. Box 7010, Rancho Santa Margarita, California 92688-7010 (United States)

    2016-06-15

    We show that in a field-reversed-configuration, the plasma is unstable to either transverse or axial rigid displacement, but never to both. Driving forces are found to be parallel to the direction of displacement with no orthogonal components. Furthermore, we demonstrate that the properties of a resistive wall (geometry and resistivity) in the vicinity of the plasma do not affect whether the plasma is stable or unstable, but in the case of an unstable system determine the instability growth rate. Depending on the properties of the wall, the instability growth is dominated by plasma inertia (and not affected by wall resistivity) or dominated by ohmic dissipation of wall eddy currents (and thus proportional to the wall resistivity).

  16. Papyriferic acid derivatives as reversal agents of multidrug resistance in cancer cells.

    Science.gov (United States)

    Xiong, Juan; Taniguchi, Masatoshi; Kashiwada, Yoshiki; Sekiya, Michiko; Yamagishi, Takashi; Takaishi, Yoshihisa

    2010-04-15

    Forty-one derivatives of papyriferic acid were prepared based on our previous finding that methyl papyriferate (3) showed potent reversing effect on cytotoxicity of colchicine against multidrug resistance (MDR) human cancer cells (KB-C2), and evaluated for their cytotoxicity and effect on reversing P-gp-mediated MDR against KB-C2 cells. 3-O-(Morpholino-beta-oxopropanoyl)-12beta-acetoxy-3alpha,25-dihydroxy-(20S,24R)-epoxydammarane (37) significantly increased the sensitivity of colchicine against KB-C2 cells by 185-fold at 5microg/mL (7.4microM), and the cytotoxicity of colchicine was recovered to nearly that of sensitive (KB) cells. The other several new amide derivatives also exhibited potent reversal activity comparable to or more potent than methyl papyriferate and verapamil. Copyright 2010 Elsevier Ltd. All rights reserved.

  17. Effect of verapamil and other agents on the distribution of anthracyclines and on reversal of drug resistance.

    Science.gov (United States)

    Hindenburg, A A; Baker, M A; Gleyzer, E; Stewart, V J; Case, N; Taub, R N

    1987-03-01

    We studied the intracellular distribution of drugs within anthracycline-sensitive and -resistant cells by computer-assisted digitized video fluorescence microscopy. We found that the antitumor antibiotic, daunorubicin, distributes differently in anthracycline-sensitive and -resistant human leukemia cells (HL-60). Verapamil and other agents known to circumvent resistance in pleiotropic drug-resistant cell lines were able to change the pattern of distribution of daunorubicin in the anthracycline-resistant HL-60 cells back to the distribution found in anthracycline-sensitive HL-60 cells. To investigate the biochemical basis for this effect, we studied the distribution of daunorubicin and doxorubicin in a hydrophobic/hydrophilic (membrane/cytoplasmic) environment using the two-compartment cell-free system of Folch. Our results demonstrate that various unrelated drugs known to overcome resistance will also change the distribution of the anthracyclines in the hydrophobic/hydrophilic compartments. Our data allow the hypothesis that various unrelated agents known to circumvent resistance may act by altering the hydrophobic/hydrophilic solubility of anthracyclines in the resistant cell.

  18. 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

    Directory of Open Access Journals (Sweden)

    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.

  19. The Lysine 65 Residue in HIV-1 Reverse Transcriptase Function and in Nucleoside Analog Drug Resistance

    Directory of Open Access Journals (Sweden)

    Scott J. Garforth

    2014-10-01

    Full Text Available Mutations in HIV-1 reverse transcriptase (RT that confer nucleoside analog RT inhibitor resistance have highlighted the functional importance of several active site residues (M184, Q151 and K65 in RT catalytic function. Of these, K65 residue is notable due to its pivotal position in the dNTP-binding pocket, its involvement in nucleoside analog resistance and polymerase fidelity. This review focuses on K65 residue and summarizes a substantial body of biochemical and structural studies of its role in RT function and the functional consequences of the K65R mutation.

  20. Selection, resistance risk assessment, and reversion toward susceptibility of pyriproxyfen in Musca domestica L.

    Science.gov (United States)

    Shah, Rizwan Mustafa; Abbas, Naeem; Shad, Sarfraz Ali; Sial, Ashfaq Ahmad

    2015-02-01

    Pyriproxyfen, a juvenile hormone mimic, is an effective larvicide against many pests of veterinary and public health importance. Pyriproxyfen is a biorational insecticide having many environmentally friendly attributes that make it compatible with integrated pest management programs. This experiment was performed for the assessment of resistance evolution and reversion toward susceptibility of Musca domestica to pyriproxyfen. Repeated selection at successive generations resulted in 5.09- and 130-fold increase in lethal concentration 50 (LC50) compared to field and susceptible strain, respectively. A significant decline after 22 generations without selection suggesting resistance to pyriproxyfen was unstable in M. domestica. Realized heritability (h (2)) of resistance to pyriproxyfen was 0.035 in pyriproxyfen-selected strain of M. domestica. The projected rate of resistance development indicated that, if slope = 1.28 and h (2) = 0.035, then 46-21 generations are required for 10-fold increase in LC50 at 50-90 % selection intensity. These findings suggest that a risk for resistance development to pyriproxyfen occurred in M. domestica under continuous selection pressure. Pyriproxyfen susceptibility reversed when its application is ceased for a specified duration.

  1. Resistive Wall Mode Stability and Control in the Reversed Field Pinch

    OpenAIRE

    Yadikin, Dmitriy

    2006-01-01

    Control of MHD instabilities using a conducting wall together with external magnetic fields is an important route to improved performance and reliability in fusion devices. Active control of MHD modes is of interest for both the Advanced Tokamak and the Reversed Field Pinch (RFP) configurations. A wide range of unstable, current driven MHD modes is present in the RFP. An ideally conducting wall facing the plasma can in principle provide stabilization to these modes. However, a real, resistive...

  2. Reversible resistance induced by FLT3 inhibition: a novel resistance mechanism in mutant FLT3-expressing cells.

    Directory of Open Access Journals (Sweden)

    Ellen Weisberg

    Full Text Available Clinical responses achieved with FLT3 kinase inhibitors in acute myeloid leukemia (AML are typically transient and partial. Thus, there is a need for identification of molecular mechanisms of clinical resistance to these drugs. In response, we characterized MOLM13 AML cell lines made resistant to two structurally-independent FLT3 inhibitors.MOLM13 cells were made drug resistant via prolonged exposure to midostaurin and HG-7-85-01, respectively. Cell proliferation was determined by Trypan blue exclusion. Protein expression was assessed by immunoblotting, immunoprecipitation, and flow cytometry. Cycloheximide was used to determine protein half-life. RT-PCR was performed to determine FLT3 mRNA levels, and FISH analysis was performed to determine FLT3 gene expression.We found that MOLM13 cells readily developed cross-resistance when exposed to either midostaurin or HG-7-85-01. Resistance in both lines was associated with dramatically elevated levels of cell surface FLT3 and elevated levels of phosphor-MAPK, but not phospho-STAT5. The increase in FLT3-ITD expression was at least in part due to reduced turnover of the receptor, with prolonged half-life. Importantly, the drug-resistant phenotype could be rapidly reversed upon withdrawal of either inhibitor. Consistent with this phenotype, no significant evidence of FLT3 gene amplification, kinase domain mutations, or elevated levels of mRNA was observed, suggesting that protein turnover may be part of an auto-regulatory pathway initiated by FLT3 kinase activity. Interestingly, FLT3 inhibitor resistance also correlated with resistance to cytosine arabinoside. Over-expression of FLT3 protein in response to kinase inhibitors may be part of a novel mechanism that could contribute to clinical resistance.

  3. 5FU resistance caused by reduced fluoro-deoxyuridine monophosphate and its reversal using deoxyuridine.

    Science.gov (United States)

    Mori, Ryutaro; Futamura, Manabu; Tanahashi, Toshiyuki; Tanaka, Yoshihiro; Matsuhashi, Nobuhisha; Yamaguchi, Kazuya; Yoshida, Kazuhiro

    2017-09-01

    The mechanism of 5-fluorouracil (5FU) resistance was investigated, focusing on the level of thymidylate synthase (TS) ternary complex formed with fluoro-deoxyuridine monophosphate (FdUMP). MKN45 and 5FU-resistant MKN45/F2R cells were treated with 5FU and fluoro-deoxyuridine (FdU) in combination with deoxyuridine (dU) and thymidine (dT). Subsequently, the levels of ternary complex were determined by western blotting and the cell viability was calculated using an MTT assay. MKN45/F2R cells exhibited 5FU resistance (56.2-fold relative to MKN45 cells), and demonstrated decreased orotate phosphoribosyltransferase (OPRT) and increased TS levels, requiring a higher concentration of 5FU to induce ternary complex formation than MKN45 cells. Following transfection of small interfering RNA against OPRT, MKN45 exhibited increased resistance to 5FU and decreased ternary complex formation subsequent to treatment with 5FU, indicating that decreased OPRT led to increased 5FU resistance. However, MKN45/F2R also exhibited resistance to FdU, which can be converted to FdUMP without OPRT, and there was decreased ternary complex formation after treatment with FdU, indicating that the 5FU-resistant cells had the ability to decrease intracellular FdUMP. The addition of dU and thymidine dT to 5FU promoted the formation of ternary complexes and reversed 5FU resistance in MKN45/F2R cells, although dT inhibited the efficacy of raltitrexed (another TS inhibitor). These results suggested that 5FU-resistant cells had the ability to reduce intracellular FdUMP irrespective of decreased OPRT, which led to resistance to 5FU. This resistance was then inhibited by treatment with dT or dU.

  4. Esters of the Marine-Derived Triterpene Sipholenol A Reverse P-GP-Mediated Drug Resistance

    Directory of Open Access Journals (Sweden)

    Yongchao Zhang

    2015-04-01

    Full Text Available Our previous studies showed that several sipholane triterpenes, sipholenol A, sipholenone E, sipholenol L and siphonellinol D, have potent reversal effect for multidrug resistance (MDR in cancer cells that overexpressed P-glycoprotein (P-gp/ABCB1. Through comparison of cytotoxicity towards sensitive and multi-drug resistant cell lines, we identified that the semisynthetic esters sipholenol A-4-O-acetate and sipholenol A-4-O-isonicotinate potently reversed P-gp-mediated MDR but had no effect on MRP1/ABCC1 and BCRP/ABCG2-mediated MDR. The results from [3H]-paclitaxel accumulation and efflux studies suggested that these two triterpenoids were able to increase the intracellular accumulation of paclitaxel by inhibiting its active efflux. In addition, western blot analysis revealed that these two compounds did not alter the expression levels of P-gp when treated up to 72 h. These sipholenol derivatives also stimulated the ATPase activity of P-gp membranes, which suggested that they might be substrates of P-gp. Moreover, in silico molecular docking studies revealed the virtual binding modes of these two compounds into human homology model of P-gp. In conclusion, sipholenol A-4-O-acetate and sipholenol A-4-O-isonicotinate efficiently inhibit the P-gp and may represent potential reversal agents for the treatment of multidrug resistant cancers.

  5. Structural Aspects of Drug Resistance and Inhibition of HIV-1 Reverse Transcriptase

    Directory of Open Access Journals (Sweden)

    Stefan G. Sarafianos

    2010-02-01

    Full Text Available HIV-1 Reverse Transcriptase (HIV-1 RT has been the target of numerous approved anti-AIDS drugs that are key components of Highly Active Anti-Retroviral Therapies (HAART. It remains the target of extensive structural studies that continue unabated for almost twenty years. The crystal structures of wild-type or drug-resistant mutant HIV RTs in the unliganded form or in complex with substrates and/or drugs have offered valuable glimpses into the enzyme’s folding and its interactions with DNA and dNTP substrates, as well as with nucleos(tide reverse transcriptase inhibitor (NRTI and non-nucleoside reverse transcriptase inhibitor (NNRTIs drugs. These studies have been used to interpret a large body of biochemical results and have paved the way for innovative biochemical experiments designed to elucidate the mechanisms of catalysis and drug inhibition of polymerase and RNase H functions of RT. In turn, the combined use of structural biology and biochemical approaches has led to the discovery of novel mechanisms of drug resistance and has contributed to the design of new drugs with improved potency and ability to suppress multi-drug resistant strains.

  6. Oxidative/Nitrative Stress and Inflammation Drive Progression of Doxorubicin-Induced Renal Fibrosis in Rats as Revealed by Comparing a Normal and a Fibrosis-Resistant Rat Strain.

    Directory of Open Access Journals (Sweden)

    Csaba Imre Szalay

    Full Text Available Chronic renal fibrosis is the final common pathway of end stage renal disease caused by glomerular or tubular pathologies. Genetic background has a strong influence on the progression of chronic renal fibrosis. We recently found that Rowett black hooded rats were resistant to renal fibrosis. We aimed to investigate the role of sustained inflammation and oxidative/nitrative stress in renal fibrosis progression using this new model. Our previous data suggested the involvement of podocytes, thus we investigated renal fibrosis initiated by doxorubicin-induced (5 mg/kg podocyte damage. Doxorubicin induced progressive glomerular sclerosis followed by increasing proteinuria and reduced bodyweight gain in fibrosis-sensitive, Charles Dawley rats during an 8-week long observation period. In comparison, the fibrosis-resistant, Rowett black hooded rats had longer survival, milder proteinuria and reduced tubular damage as assessed by neutrophil gelatinase-associated lipocalin (NGAL excretion, reduced loss of the slit diaphragm protein, nephrin, less glomerulosclerosis, tubulointerstitial fibrosis and matrix deposition assessed by periodic acid-Schiff, Picro-Sirius-red staining and fibronectin immunostaining. Less fibrosis was associated with reduced profibrotic transforming growth factor-beta, (TGF-β1 connective tissue growth factor (CTGF, and collagen type I alpha 1 (COL-1a1 mRNA levels. Milder inflammation demonstrated by histology was confirmed by less monocyte chemotactic protein 1 (MCP-1 mRNA. As a consequence of less inflammation, less oxidative and nitrative stress was obvious by less neutrophil cytosolic factor 1 (p47phox and NADPH oxidase-2 (p91phox mRNA. Reduced oxidative enzyme expression was accompanied by less lipid peroxidation as demonstrated by 4-hydroxynonenal (HNE and less protein nitrosylation demonstrated by nitrotyrosine (NT immunohistochemistry and quantified by Western blot. Our results demonstrate that mediators of fibrosis

  7. Identification of CREB3L1 as a Biomarker Predicting Doxorubicin Treatment Outcome.

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    Bray Denard

    Full Text Available Doxorubicin has been shown to inhibit proliferation of cancer cells through proteolytic activation of CREB3L1 (cAMP response element binding protein 3-like 1, a transcription factor synthesized as a membrane-bound precursor. Upon doxorubicin treatment, CREB3L1 is cleaved so that the N-terminal domain of the protein can reach the nucleus where it activates transcription of genes that inhibit cell proliferation. These results suggest that the level of CREB3L1 in cancer cells may determine their sensitivity to doxorubicin.Mice transplanted with 6 lines of renal cell carcinoma (RCC were injected with doxorubicin to observe the effect of the chemotherapy on tumor growth. Immunohistochemistry and bioinformatics analyses were performed to compare CREB3L1 levels in types of cancer known to respond to doxorubicin versus those resistant to doxorubicin.Higher levels of CREB3L1 protein are correlated with increased doxorubicin sensitivity of xenograft RCC tumors (p = 0.017 by Pearson analysis. From patient tumor biopsies we analyzed, CREB3L1 was expressed in 19% of RCC, which is generally resistant to doxorubicin, but in 70% of diffuse large B-cell lymphoma that is sensitive to doxorubicin. Doxorubicin is used as the standard treatment for cancers that express the highest levels of CREB3L1 such as osteosarcoma and malignant fibrous histiocytoma but is not generally used to treat those that express the lowest levels of CREB3L1 such as RCC.Identification of CREB3L1 as the biomarker for doxorubicin sensitivity may markedly improve the doxorubicin response rate by applying doxorubicin only to patients with cancers expressing CREB3L1.

  8. Engineered reversal of drug resistance in cancer cells--metastases suppressor factors as change agents.

    Science.gov (United States)

    Yadav, Vinod Kumar; Kumar, Akinchan; Mann, Anita; Aggarwal, Suruchi; Kumar, Maneesh; Roy, Sumitabho Deb; Pore, Subrata Kumar; Banerjee, Rajkumar; Mahesh Kumar, Jerald; Thakur, Ram Krishna; Chowdhury, Shantanu

    2014-01-01

    Building molecular correlates of drug resistance in cancer and exploiting them for therapeutic intervention remains a pressing clinical need. To identify factors that impact drug resistance herein we built a model that couples inherent cell-based response toward drugs with transcriptomes of resistant/sensitive cells. To test this model, we focused on a group of genes called metastasis suppressor genes (MSGs) that influence aggressiveness and metastatic potential of cancers. Interestingly, modeling of 84 000 drug response transcriptome combinations predicted multiple MSGs to be associated with resistance of different cell types and drugs. As a case study, on inducing MSG levels in a drug resistant breast cancer line resistance to anticancer drugs caerulomycin, camptothecin and topotecan decreased by more than 50-60%, in both culture conditions and also in tumors generated in mice, in contrast to control un-induced cells. To our knowledge, this is the first demonstration of engineered reversal of drug resistance in cancer cells based on a model that exploits inherent cellular response profiles.

  9. The Reversal Effect and Its Mechanisms of Tetramethylpyrazine on Multidrug Resistance in Human Bladder Cancer.

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    Shanshan Wang

    Full Text Available Chemotherapy is an important strategy for the treatment of bladder cancer. However, the main problem limiting the success of chemotherapy is the development of multidrug resistance (MDR. To improve the management of bladder cancer, it is an urgent matter to search for strategies to reverse MDR. We chose three kinds of herbal medicines including ginsenoside Rh2, (--Epigallocatechin gallate (EGCG and Tetramethylpyrazine (TMP to detect their effects on bladder cancer. Reversal effects of these three herbal medicines for drug resistance in adriamycin (ADM-resistant Pumc-91 cells (Pumc-91/ADM were assessed by Cell Counting Kit-8 (CCK-8 cell proliferation assay system. The mechanisms of reversal effect for TMP were explored in Pumc-91/ADM and T24/DDP cells. After Pumc-91/ADM and T24/DDP cells were treated with TMP, cell cycle distribution analysis was performed by flow cytometry. The expression of MRP1, GST, BCL-2, LRP and TOPO-II was evaluated using quantitative real-time polymerase chain reaction (qRT-PCR, immunefluorescence assay and western blot. It was observed that TMP was capable of enhancing the cytotoxicity of anticancer agents on Pumc-91/ADM cells in response to ADM, however Rh2 and EGCG were unable to. The reversal effect of TMP was also demonstrated in T24/DDP cells. Moreover, the treatment with TMP in Pumc-91/ADM and T24/DDP cells led to an increased of G1 phase accompanied with a concomitant decrease of cell numbers in S phase. Compared to the control group, an obvious decrease of MRP1, GST, BCL-2 and an increase of TOPO-II were shown in TMP groups with a dose-dependency in mRNA and protein levels. However, there was no difference on LRP expression between TMP groups and the control group. TMP could effectively reverse MDR of Pumc-91/ADM and T24/DDP cells and its mechanisms might be correlated with the alteration of MRP1, GST, BCL-2 and TOPO-II. TMP might be a potential candidate for reversing drug resistance in bladder cancer

  10. Reversal of muscle insulin resistance with exercise reduces postprandial hepatic de novo lipogenesis in insulin resistant individuals.

    Science.gov (United States)

    Rabøl, Rasmus; Petersen, Kitt Falk; Dufour, Sylvie; Flannery, Clare; Shulman, Gerald I

    2011-08-16

    Skeletal muscle insulin resistance has been implicated in the pathogenesis of nonalcoholic fatty liver disease (NAFLD) and atherogenic dyslipidemia associated with the metabolic syndrome by altering the distribution pattern of postprandial energy storage. We conducted a study to examine this hypothesis by reversing muscle insulin resistance with a single bout of exercise and measuring hepatic de novo lipogenesis and hepatic triglyceride synthesis after a carbohydrate-rich meal. We studied 12 healthy, young, lean, insulin resistant individuals in an interventional, randomized cross-over trial. The response to the ingestion of a carbohydrate-rich meal was studied at rest and after one 45-min bout of exercise on an elliptical trainer. Hepatic de novo lipogenesis was assessed by using (2)H(2)O, and changes in glycogen and fat content in liver and muscle were measured by (13)C and (1)H magnetic resonance spectroscopy, respectively. Exercise resulted in a greater than threefold increase in postprandial net muscle glycogen synthesis (P novo lipogenesis (P < 0.01) and were independent of changes in fasting or postprandial plasma glucose and insulin concentrations. These data demonstrate that skeletal muscle insulin resistance is an early therapeutic target for the treatment and prevention of atherogenic dyslipidemia and NAFLD in young insulin resistant individuals who are prone to develop the metabolic syndrome and type 2 diabetes.

  11. Biochemical adaptations of mammalian hibernation: exploring squirrels as a perspective model for naturally induced reversible insulin resistance

    Directory of Open Access Journals (Sweden)

    C-W. Wu

    2013-01-01

    Full Text Available An important disease among human metabolic disorders is type 2 diabetes mellitus. This disorder involves multiple physiological defects that result from high blood glucose content and eventually lead to the onset of insulin resistance. The combination of insulin resistance, increased glucose production, and decreased insulin secretion creates a diabetic metabolic environment that leads to a lifetime of management. Appropriate models are critical for the success of research. As such, a unique model providing insight into the mechanisms of reversible insulin resistance is mammalian hibernation. Hibernators, such as ground squirrels and bats, are excellent examples of animals exhibiting reversible insulin resistance, for which a rapid increase in body weight is required prior to entry into dormancy. Hibernator studies have shown differential regulation of specific molecular pathways involved in reversible resistance to insulin. The present review focuses on this growing area of research and the molecular mechanisms that regulate glucose homeostasis, and explores the roles of the Akt signaling pathway during hibernation. Here, we propose a link between hibernation, a well-documented response to periods of environmental stress, and reversible insulin resistance, potentially facilitated by key alterations in the Akt signaling network, PPAR-γ/PGC-1α regulation, and non-coding RNA expression. Coincidentally, many of the same pathways are frequently found to be dysregulated during insulin resistance in human type 2 diabetes. Hence, the molecular networks that may regulate reversible insulin resistance in hibernating mammals represent a novel approach by providing insight into medical treatment of insulin resistance in humans.

  12. Biochemical adaptations of mammalian hibernation: exploring squirrels as a perspective model for naturally induced reversible insulin resistance.

    Science.gov (United States)

    Wu, C-W; Biggar, K K; Storey, K B

    2013-01-01

    An important disease among human metabolic disorders is type 2 diabetes mellitus. This disorder involves multiple physiological defects that result from high blood glucose content and eventually lead to the onset of insulin resistance. The combination of insulin resistance, increased glucose production, and decreased insulin secretion creates a diabetic metabolic environment that leads to a lifetime of management. Appropriate models are critical for the success of research. As such, a unique model providing insight into the mechanisms of reversible insulin resistance is mammalian hibernation. Hibernators, such as ground squirrels and bats, are excellent examples of animals exhibiting reversible insulin resistance, for which a rapid increase in body weight is required prior to entry into dormancy. Hibernator studies have shown differential regulation of specific molecular pathways involved in reversible resistance to insulin. The present review focuses on this growing area of research and the molecular mechanisms that regulate glucose homeostasis, and explores the roles of the Akt signaling pathway during hibernation. Here, we propose a link between hibernation, a well-documented response to periods of environmental stress, and reversible insulin resistance, potentially facilitated by key alterations in the Akt signaling network, PPAR-γ/PGC-1α regulation, and non-coding RNA expression. Coincidentally, many of the same pathways are frequently found to be dysregulated during insulin resistance in human type 2 diabetes. Hence, the molecular networks that may regulate reversible insulin resistance in hibernating mammals represent a novel approach by providing insight into medical treatment of insulin resistance in humans.

  13. Biochemical adaptations of mammalian hibernation: exploring squirrels as a perspective model for naturally induced reversible insulin resistance

    Energy Technology Data Exchange (ETDEWEB)

    Wu, C-W.; Biggar, K.K.; Storey, K.B. [Carleton University, Department of Biology, Institute of Biochemistry, Ottawa, ON (Canada)

    2013-01-28

    An important disease among human metabolic disorders is type 2 diabetes mellitus. This disorder involves multiple physiological defects that result from high blood glucose content and eventually lead to the onset of insulin resistance. The combination of insulin resistance, increased glucose production, and decreased insulin secretion creates a diabetic metabolic environment that leads to a lifetime of management. Appropriate models are critical for the success of research. As such, a unique model providing insight into the mechanisms of reversible insulin resistance is mammalian hibernation. Hibernators, such as ground squirrels and bats, are excellent examples of animals exhibiting reversible insulin resistance, for which a rapid increase in body weight is required prior to entry into dormancy. Hibernator studies have shown differential regulation of specific molecular pathways involved in reversible resistance to insulin. The present review focuses on this growing area of research and the molecular mechanisms that regulate glucose homeostasis, and explores the roles of the Akt signaling pathway during hibernation. Here, we propose a link between hibernation, a well-documented response to periods of environmental stress, and reversible insulin resistance, potentially facilitated by key alterations in the Akt signaling network, PPAR-γ/PGC-1α regulation, and non-coding RNA expression. Coincidentally, many of the same pathways are frequently found to be dysregulated during insulin resistance in human type 2 diabetes. Hence, the molecular networks that may regulate reversible insulin resistance in hibernating mammals represent a novel approach by providing insight into medical treatment of insulin resistance in humans.

  14. Rational design of antibiotic treatment plans: a treatment strategy for managing evolution and reversing resistance.

    Science.gov (United States)

    Mira, Portia M; Crona, Kristina; Greene, Devin; Meza, Juan C; Sturmfels, Bernd; Barlow, Miriam

    2015-01-01

    The development of reliable methods for restoring susceptibility after antibiotic resistance arises has proven elusive. A greater understanding of the relationship between antibiotic administration and the evolution of resistance is key to overcoming this challenge. Here we present a data-driven mathematical approach for developing antibiotic treatment plans that can reverse the evolution of antibiotic resistance determinants. We have generated adaptive landscapes for 16 genotypes of the TEM β-lactamase that vary from the wild type genotype "TEM-1" through all combinations of four amino acid substitutions. We determined the growth rate of each genotype when treated with each of 15 β-lactam antibiotics. By using growth rates as a measure of fitness, we computed the probability of each amino acid substitution in each β-lactam treatment using two different models named the Correlated Probability Model (CPM) and the Equal Probability Model (EPM). We then performed an exhaustive search through the 15 treatments for substitution paths leading from each of the 16 genotypes back to the wild type TEM-1. We identified optimized treatment paths that returned the highest probabilities of selecting for reversions of amino acid substitutions and returning TEM to the wild type state. For the CPM model, the optimized probabilities ranged between 0.6 and 1.0. For the EPM model, the optimized probabilities ranged between 0.38 and 1.0. For cyclical CPM treatment plans in which the starting and ending genotype was the wild type, the probabilities were between 0.62 and 0.7. Overall this study shows that there is promise for reversing the evolution of resistance through antibiotic treatment plans.

  15. Rational design of antibiotic treatment plans: a treatment strategy for managing evolution and reversing resistance.

    Directory of Open Access Journals (Sweden)

    Portia M Mira

    Full Text Available The development of reliable methods for restoring susceptibility after antibiotic resistance arises has proven elusive. A greater understanding of the relationship between antibiotic administration and the evolution of resistance is key to overcoming this challenge. Here we present a data-driven mathematical approach for developing antibiotic treatment plans that can reverse the evolution of antibiotic resistance determinants. We have generated adaptive landscapes for 16 genotypes of the TEM β-lactamase that vary from the wild type genotype "TEM-1" through all combinations of four amino acid substitutions. We determined the growth rate of each genotype when treated with each of 15 β-lactam antibiotics. By using growth rates as a measure of fitness, we computed the probability of each amino acid substitution in each β-lactam treatment using two different models named the Correlated Probability Model (CPM and the Equal Probability Model (EPM. We then performed an exhaustive search through the 15 treatments for substitution paths leading from each of the 16 genotypes back to the wild type TEM-1. We identified optimized treatment paths that returned the highest probabilities of selecting for reversions of amino acid substitutions and returning TEM to the wild type state. For the CPM model, the optimized probabilities ranged between 0.6 and 1.0. For the EPM model, the optimized probabilities ranged between 0.38 and 1.0. For cyclical CPM treatment plans in which the starting and ending genotype was the wild type, the probabilities were between 0.62 and 0.7. Overall this study shows that there is promise for reversing the evolution of resistance through antibiotic treatment plans.

  16. New Roads Leading to Old Destinations: Efflux Pumps as Targets to Reverse Multidrug Resistance in Bacteria

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    Gabriella Spengler

    2017-03-01

    Full Text Available Multidrug resistance (MDR has appeared in response to selective pressures resulting from the incorrect use of antibiotics and other antimicrobials. This inappropriate application and mismanagement of antibiotics have led to serious problems in the therapy of infectious diseases. Bacteria can develop resistance by various mechanisms and one of the most important factors resulting in MDR is efflux pump-mediated resistance. Because of the importance of the efflux-related multidrug resistance the development of new therapeutic approaches aiming to inhibit bacterial efflux pumps is a promising way to combat bacteria having over-expressed MDR efflux systems. The definition of an efflux pump inhibitor (EPI includes the ability to render the bacterium increasingly more sensitive to a given antibiotic or even reverse the multidrug resistant phenotype. In the recent years numerous EPIs have been developed, although so far their clinical application has not yet been achieved due to their in vivo toxicity and side effects. In this review, we aim to give a short overview of efflux mediated resistance in bacteria, EPI compounds of plant and synthetic origin, and the possible methods to investigate and screen EPI compounds in bacterial systems.

  17. Piperine reverses high fat diet-induced hepatic steatosis and insulin resistance in mice.

    Science.gov (United States)

    Choi, Seoyoon; Choi, Youngshim; Choi, Yeji; Kim, Sohee; Jang, Jeehee; Park, Taesun

    2013-12-15

    This study examined the effect of piperine on hepatic steatosis and insulin resistance induced in mice by feeding a high-fat diet (HFD) for 13 weeks and elucidated potential underlying molecular mechanisms. Administration of piperine (50 mg/kg body weight) to mice with HFD-induced hepatic steatosis resulted in a significant increase in plasma adiponectin levels. Also, elevated plasma concentrations of insulin and glucose and hepatic lipid levels induced by feeding a HFD were reversed in mice when they were administered piperine. However, piperine did not reduce body weight and other biochemical markers to an extent where they became equal to the levels found in the CD-fed mice. Piperine reversed HFD-induced down-regulation of adiponecitn-AMP-activated protein kinase (AMPK) signalling molecules which play an important role in mediating lipogenesis, fatty acid oxidation and insulin signalling in the livers of mice. The expressions of lipogenic target genes were decreased, whereas the expression of carnitine palmitoyltransferase 1 (CPT1) gene involved in fatty acid oxidation was increased in the livers of the Pin50 group. Piperine significantly decreased the phosphorylation of insulin receptor substrate-1 (IRS-1) compared with the HFD-fed mice. Administration of piperine appeared to reverse preexisting HFD-induced hepatic steatosis and insulin resistance, probably by activation of adiponectin-AMPK signalling in mice. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. [Drug resistance reversal of HL-60/ADR cells by simultaneous suppression of XIAP and MRP].

    Science.gov (United States)

    Wang, Xiao-Fang; Wang, Chun; Qin, You-Wen; Yan, Shi-Ke; Gao, Yan-Rong

    2006-12-01

    This study was purposed to explore the mechanisms of drug resistance of HL-60/ADR cells and to compare the reversal drug-resistance effects of antisense oligonucleotides (AS ODN) of XIAP (X-linked inhibitor of apoptosis protein) and AS ODNs of MRP (multidrug resistance-associated protein) by use alone or in combination. Reverse transcription-PCR and Western blot were applied to detect the expression of XIAP, BCL-2, MRP and MDR1 in mRNA and protein levels of HL-60 cells and HL-60/ADR cells, respectively. Fully phosphorothioated AS ODN of XIAP and MRP was delivered into HL-60/ADR cells with Lipofectamine 2000 in the form of liposome-ODN complexes alone or in combination. CCK-8 cell viability assay was used to determine the effect of AS ODN of XIAP and MRP used alone or in combination on the chemotherapy sensitivity of HL-60/ADR cells to daunorubicin (DNR). Reverse transcription-PCR and Western blot were applied to examine the changes of XIAP, MRP in mRNA and protein levels respectively. The results showed that MRP and XIAP were both significantly higher in HL-60/ADR cells than those in HL-60 cells. AS ODN of XIAP and MRP down-regulated the expression of XIAP and MRP in HL-60/ADR cells and increased the sensitivity of HL-60/ADR cells to DNR, respectively. AS ODN of XIAP + MRP did not enhance the inhibition expression of XIAP in HL-60/ADR cells but increased the sensitivity of HL-60/ADR cells to DNR significantly as compared with AS ODN of XIAP (P MRP did not increase the concentration of DNR nor enhanced the inhibition expression of MRP in HL-60/ADR cells but increased the sensitivity of HL-60/ADR cells to DNR significantly (P MRP. It is concluded that both XIAP and MRP may be involved in the drug resistance mechanisms of HL-60/ADR cells. Drug-resistance of HL-60/ADR cells can be reversed significantly when antisense oligonucleotides of XIAP and MRP were used in combination.

  19. Identification of specific reversal agents for Leishmania ABCI4-mediated antimony resistance by flavonoid and trolox derivative screening.

    Science.gov (United States)

    Manzano, José Ignacio; Lecerf-Schmidt, Florine; Lespinasse, Marie-Ange; Di Pietro, Attilio; Castanys, Santiago; Boumendjel, Ahcène; Gamarro, Francisco

    2014-03-01

    To identify reversal agents for the Leishmania ABCI4 transporter that confers resistance to antimony. Selective ABCI4 inhibitors among a series of 15 flavonoid and trolox derivatives or analogues were investigated by evaluating their ability to reverse antimony resistance in Leishmania parasites overexpressing ABCI4. Among the compounds screened, N-ethyltrolox carboxamide (compound D2) produced the highest reversal activity. In order to optimize the activity of D2, we synthesized a series of 10 derivatives by condensation of various amines with trolox. Analysis of antimony resistance reversal activity showed that N-propyltrolox carboxamide (compound D4) was the most potent ABCI4 inhibitor, with reversal activity being maintained in the intracellular amastigote stage. In addition, trolox derivatives significantly reverted the resistance to zinc protoporphyrin. The mechanism of action of these active derivatives was found to be related to significant reversion of Sb(III) and zinc protoporphyrin accumulation and to a decrease in drug efflux. Our findings suggest that trolox derivatives D2 and D4 could be considered to be specific reversal agents targeting the Leishmania ABCI4 transporter. The structure-activity relationship obtained in the present study highlights the importance of the size and length of the alkyl substituent linked to trolox. Furthermore, the structural data obtained provide valuable information for the further development of new, even more specific and potent Leishmania ABCI4 reversal agents.

  20. The Effect of Caffeine and chk2 Inhibitor on Doxorubicin-Induced Cellular Senescence in MCF-7 Cells.

    Science.gov (United States)

    Mohammadrezaei, F Mir; Movaghar, A Fayyaz; Gharghabi, M

    2016-09-01

    Senescence is cellular growth arrest. Induction of senescence can be considered as an alternative approach for treating cancer cells being resistance to anti-cancer drugs. We investigated the effect of caffeine and chk2 inhibitor on doxorubicin induced senescence in MCF-7 cells. Caffeine and chk2 inhibitor were used in combination with doxorubicin. Cellular senescence was assessed by β-galactosidase assay. P21 expression was determined using immunoblotting. Cell proliferation was evaluated using prestoblue assay. Results revealed that doxorubicin induced senescence and increased p21 expression in MCF-7 cells. However, co-treatment of chk2 inhibitor and caffeine with doxorubicin could not augment doxorubicin-induced senescence. Moreover, p21 expression was decreased in combination studies compared to doxorubicin group. Our results indicate that caffeine, chk2 inhibitor and combination of chk2 inhibitor, caffeine and doxorubicin could not increase sensitivity of the cells to doxorubicin-induced senescence. Our findings demonstrate that low-dose doxorubicin induced senescence via the activation of ATM, -chk2, and -p21 pathways, while inhibition of ATM and chk2 cannot consider as a new target for sensitization of MCF-7 cells to doxorubicin. Thus, chk2 inhibitor and caffeine might not serve as desirable agents being capable to restore chemo sensitivity in doxorubicin-resistant breast tumors. © Georg Thieme Verlag KG Stuttgart · New York.

  1. Peripheral Cannabinoid-1 Receptor Inverse Agonism Reduces Obesity by Reversing Leptin Resistance

    Science.gov (United States)

    Tam, Joseph; Cinar, Resat; Liu, Jie; Godlewski, Grzegorz; Wesley, Daniel; Jourdan, Tony; Szanda, Gergö; Mukhopadhyay, Bani; Chedester, Lee; Liow, Jeih-San; Innis, Robert B.; Cheng, Kejun; Rice, Kenner C.; Deschamps, Jeffrey R.; Chorvat, Robert J.; McElroy, John F.; Kunos, George

    2013-01-01

    SUMMARY Obesity-related leptin resistance manifests in loss of leptin’s ability to reduce appetite and increase energy expenditure. Obesity is also associated with increased activity of the endocannabinoid system, and CB1 receptor (CB1R) inverse agonists reduce body weight and the associated metabolic complications, although adverse neuropsychiatric effects halted their therapeutic development. Here we show that in mice with diet-induced obesity (DIO), the peripherally restricted CB1R inverse agonist JD5037 is equieffective with its brain-penetrant parent compound in reducing appetite, body weight, hepatic steatosis, and insulin resistance, even though it does not occupy central CB1R or induce related behaviors. Appetite and weight reduction by JD5037 are mediated by resensitizing DIO mice to endogenous leptin through reversing the hyperleptinemia by decreasing leptin expression and secretion by adipocytes and increasing leptin clearance via the kidney. Thus, inverse agonism at peripheral CB1R not only improves cardiometabolic risk in obesity but has antiobesity effects by reversing leptin resistance. PMID:22841573

  2. Interfering EZH2 Expression Reverses the Cisplatin Resistance in Human Ovarian Cancer by Inhibiting Autophagy.

    Science.gov (United States)

    Sun, Yang; Jin, Long; Liu, Jia-Hua; Sui, Yu-Xia; Han, Li-Li; Shen, Xiao-Li

    2016-09-01

    We aimed to determine the effects of the inhibition of enhancer of zeste homolog 2 (EZH2) gene expression on the cisplatin resistance of the human ovarian cancer cell line, SKOV3/DDP, and to identify the underlying mechanisms. SKOV3/DDP cells were stably transfected with pSUPER-EZH2 (EZH2 RNA interference plasmid) or pcDNA3.1-EZH2 (EZH2 gene overexpression plasmid) using the lipofection method. Real-time fluorescence quantitative reverse transcription polymerase chain reaction and western blotting confirmed that EZH2 expression was downregulated in pSUPER-EZH2-transfected cells. Flow cytometry revealed that EZH2 inhibition did not induce apoptosis, but significantly inhibited autophagy. In addition, it significantly increased the expression of the cellular senescence-signaling proteins p14(ARF), p16(INK4a), p53, pRb, and p21, and significantly decreased the expression of cyclin-dependent kinase (CDK)1, CDK2, and H3K27me3. Cellular senescence was characterized by a significant increase in the G0/G1 ratio and the restoration of sensitivity to cisplatin in the drug-resistant cells. These findings suggest that interfering with EZH2 expression can inhibit SKOV3/DDP cell autophagy and reverse resistance to cisplatin. The underlying mechanisms could be associated with the regulation of the cellular senescence-signaling pathway.

  3. Curcumin reverses the depressive-like behavior and insulin resistance induced by chronic mild stress.

    Science.gov (United States)

    Shen, Ji-Duo; Wei, Yu; Li, Yu-Jie; Qiao, Jing-Yi; Li, Yu-Cheng

    2017-08-01

    Increasing evidence has demonstrated that patients with depression have a higher risk of developing type 2 diabetes. Insulin resistance has been identified as the key mechanism linking depression and diabetes. The present study established a rat model of depression complicated by insulin resistance using a 12-week exposure to chronic mild stress (CMS) and investigated the therapeutic effects of curcumin. Sucrose intake tests were used to evaluate depressive-like behaviors, and oral glucose tolerance tests (OGTT) and intraperitoneal insulin tolerance tests (IPITT) were performed to evaluate insulin sensitivity. Serum parameters were detected using commercial kits. Real-time quantitative PCR was used to examine mRNA expression. CMS rats exhibited reduced sucrose consumption, increased serum glucose, insulin, triglyceride (TG), low density lipoprotein-cholesterol (LDL-C), non-esterified fatty acid (NEFA), glucagon, leptin, and corticosterone levels, as well as impaired insulin sensitivity. Curcumin upregulated the phosphorylation of insulin receptor substrate (IRS)-1 and protein kinase B (Akt) in the liver, enhanced insulin sensitivity, and reversed the metabolic abnormalities and depressive-like behaviors mentioned above. Moreover, curcumin increased the hepatic glycogen content by inhibiting glycogen synthase kinase (GSK)-3β and prevented gluconeogenesis by inhibiting phosphoenolpyruvate carboxykinase (PEPCK) and glucose 6-phosphatase (G6Pase). These results suggest that curcumin not only exerted antidepressant-like effects, but also reversed the insulin resistance and metabolic abnormalities induced by CMS. These data may provide evidence to support the potential use of curcumin against depression and/or metabolic disorders.

  4. Synthetic organotelluride compounds induce the reversal of Pdr5p mediated fluconazole resistance in Saccharomyces cerevisiae

    Science.gov (United States)

    2014-01-01

    Background Resistance to fluconazole, a commonly used azole antifungal, is a challenge for the treatment of fungal infections. Resistance can be mediated by overexpression of ABC transporters, which promote drug efflux that requires ATP hydrolysis. The Pdr5p ABC transporter of Saccharomyces cerevisiae is a well-known model used to study this mechanism of antifungal resistance. The present study investigated the effects of 13 synthetic compounds on Pdr5p. Results Among the tested compounds, four contained a tellurium-butane group and shared structural similarities that were absent in the other tested compounds: a lateral hydrocarbon chain and an amide group. These four compounds were capable of inhibiting Pdr5p ATPase activity by more than 90%, they demonstrated IC50 values less than 2 μM and had an uncompetitive pattern of Pdr5p ATPase activity inhibition. These organotellurides did not demonstrate cytotoxicity against human erythrocytes or S. cerevisiae mutant strains (a strain that overexpress Pdr5p and a null mutant strain) even in concentrations above 100 μM. When tested at 100 μM, they could reverse the fluconazole resistance expressed by both the S. cerevisiae mutant strain that overexpress Pdr5p and a clinical isolate of Candida albicans. Conclusions We have identified four organotellurides that are promising candidates for the reversal of drug resistance mediated by drug efflux pumps. These molecules will act as scaffolds for the development of more efficient and effective efflux pump inhibitors that can be used in combination therapy with available antifungals. PMID:25062749

  5. A New Class of Safe, Potent, and Specific P-gp Modulator: Flavonoid Dimer FD18 Reverses P-gp-Mediated Multidrug Resistance in Human Breast Xenograft in Vivo.

    Science.gov (United States)

    Yan, Clare S W; Wong, Iris L K; Chan, Kin-Fai; Kan, Jason W Y; Chong, Tsz Cheung; Law, Man Chun; Zhao, Yunzhe; Chan, Shun Wan; Chan, Tak Hang; Chow, Larry M C

    2015-10-05

    Flavonoid dimer FD18 is a new class of dimeric P-gp modulator that can reverse cancer drug resistance. FD18 is a potent (EC50 = 148 nM for paclitaxel), safe (selective index = 574), and selective P-glycoprotein (P-gp) modulator. FD18 can modulate multidrug resistance toward paclitaxel, vinblastine, vincristine, doxorubicin, daunorubicin, and mitoxantrone in human breast cancer LCC6MDR in vitro. FD18 (1 μM) can revert chemosensitivity of LCC6MDR back to parental LCC6 level. FD18 was 11- to 46-fold more potent than verapamil. FD18 (1 μM) can increase accumulation of doxorubicin by 2.7-fold, daunorubicin (2.1-fold), and rhodamine 123 (5.2-fold) in LCC6MDR. FD18 inhibited P-gp-mediated doxorubicin efflux and has no effect on influx. FD18 at 1 μM did not affect the protein expression level of P-gp. Pharmacokinetics studies indicated that intraperitoneal administration of 45 mg/kg FD18 was enough to maintain a plasma level above EC50 (148 nM) for more than 600 min. Toxicity studies with FD18 (90 mg/kg, i.p. for 12 times in 22 days) with paclitaxel (12 mg/kg, i.v. for 12 times in 22 days) revealed no obvious toxicity or death in mice. In vivo efficacy studies indicated that FD18 (45 mg/kg, i.p. for 12 times in 22 days) together with paclitaxel (12 mg/kg, i.v. for 12 times in 22 days) resulted in a 46% reduction in LCC6MDR xenograft volume (n = 11; 648 ± 84 mm(3)) compared to paclitaxel control (n = 8; 1201 ± 118 mm(3)). There were no animal deaths or significant drop in body weight and vital organ wet weight. FD18 can increase paclitaxel accumulation in LCC6MDR xenograft by 1.8- to 2.2-fold. The present study suggests that FD18 represents a new class of safe and potent P-gp modulator in vivo.

  6. NF-κB inhibitor reverses temozolomide resistance in human glioma TR/U251 cells.

    Science.gov (United States)

    Wang, Xuan; Jia, Lili; Jin, Xiaohua; Liu, Qian; Cao, Wei; Gao, Xiangdong; Yang, Mingfeng; Sun, Baoliang

    2015-06-01

    Glioblastoma multiforme (GBM) demonstrates an unsatisfactory clinical prognosis due to the intrinsic or acquired resistance to temozolomide (TMZ) exhibited by the tumors. One possible cause of TMZ resistance in GBM is the overexpression of O6-methylguanine-DNA methyltransferase (MGMT), which can repair the TMZ-induced guanine damage in DNA. Additionally, excessive activated NF-κB is reported to be a component of the major inflammatory transcription pathway that is associated with TMZ resistance in GBM. However, the association between the NF-κB pathway and MGMT expression in GBM cells is unknown. Therefore, in the present study, the TMZ resistant (TR) U251 cell line (TR/U251) was successfully constructed to detect how the TR/U251 cell line and the parental U251 cell line each interact with TMZ in vitro. The TR/U251 cells were approximately five times more resistant to TMZ compared with the parental cells. Furthermore, it was found that the NF-κB inhibitor BAY 11-7082 suppressed the expression of MGMT in TR/U251 cells and enhanced TMZ-induced cytotoxicity and apoptosis, thereby indicating that the NF-κB pathway and MGMT interact to promote TMZ resistance. The inhibition of NF-κB may be a promising strategy to reverse drug resistance in TR glioma cells. The present results propose a potential mechanism for using the NF-κB inhibitor BAY 11-7082 as a potential therapy for the treatment of TR glioma. Although BAY 11-7082 is a well-known NF-κB inhibitor, the present study further investigated its underlying mechanisms through a series of new experiments.

  7. Restoration of chemosensitivity by multifunctional micelles mediated by P-gp siRNA to reverse MDR.

    Science.gov (United States)

    Shen, Jie; Wang, Qiwen; Hu, Qida; Li, Yongbing; Tang, Guping; Chu, Paul K

    2014-10-01

    One of the main obstacles in tumor therapy is multiple drug resistance (MDR) and an underlying mechanism of MDR is up-regulation of the transmembrane ATP-binding cassette (ABC) transporter proteins, especially P-glycoprotein (P-gp). In the synergistic treatment of siRNA and anti-cancer drug doxorubicin, it is crucial that both the siRNA and doxorubicin are simultaneously delivered to the tumor cells and the siRNA can fleetly down-regulate P-g before doxorubicin inactivates the P-gp and is pumped out. Herein, a type of micelles comprising a polycationic PEI-CyD shell to condense the siRNA and hydrophobic core to package doxorubicin is reported. The structure of the polymer is determined by (1)H NMR, FT-IR, DSC, and XRD and the micelles are characterized by DLS, 2D-NOESY NMR, and TEM to study the self-assembly of the micelles with siRNA and drugs. In vitro studies demonstrate controlled release and temporal enhancement of the therapeutic efficacy of P-gp siRNA and doxorubicin. Release of siRNA down-regulates the mRNA and protein levels of P-gp in the MCF-7/ADR cell lines effectively and the accumulated doxorubicin facilitates apoptosis of the cells to reverse MDR. Moreover, in vivo research reveals that the siRNA and doxorubicin loaded micelles induce tumor cell apoptosis and inhibit the growth of MDR tumor. The western blotting and RT-PCR results illustrate that the synergistic treatment of siRNA and doxorubicin leads to efficient reduction of the P-gp expression as well as cell apoptotic induction in MDR tumors at a small dosage of 0.5 mg/kg. The micelles have large clinical potential in drug/RNAi synergistic treatment via restoration of the chemosensitivity in MDR cancer therapy. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Euphorbia Species-derived Diterpenes and Coumarins as Multidrug Resistance Modulators in Human Colon Carcinoma Cells.

    Science.gov (United States)

    Wiśniewski, Jerzy; Wesołowska, Olga; Środa-Pomianek, Kamila; Paprocka, Maria; Bielawska-Pohl, Aleksandra; Krawczenko, Agnieszka; Duarte, Noelia; Ferreira, Maria-José U; Duś, Danuta; Michalak, Krystyna

    2016-05-01

    Recently, many new potent multidrug resistance (MDR) reversal agents have been discovered, among them lathyrane and jatrophane diterpenes isolated from various Euphorbia species. In the present study, the cytotoxicity, P-glycoprotein inhibition activity, and MDR reversal potency of six diterpenes and two coumarins from two Euphorbia species were studied in human colon carcinoma LoVo cells, and doxorubicin-resistant, LoVo/Dx cells. Cytotoxicity of the studied compounds (alone and in combination with doxorubicin) was investigated. Inhibition of P-glycoprotein transport activity was monitored by flow cytometry. Changes in intracellular doxorubicin accumulation were observed by means of fluorescence microscopy. Latilagascene B was demonstrated to be an effective P-glycoprotein inhibitor, able to increase doxorubicin accumulation in resistant cells, however not able to restore doxorubicin cytotoxicity in LoVo/Dx cells. The structure of latilagascene B seems to be an interesting candidate for further synthesis of new derivatives of reduced cytotoxicity and high anti-MDR potency. Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  9. Panitumumab and pegylated liposomal doxorubicin in platinum-resistant epithelial ovarian cancer with KRAS wild-type: the PaLiDo study, a phase II nonrandomized multicenter study.

    Science.gov (United States)

    Steffensen, Karina Dahl; Waldstrøm, Marianne; Pallisgård, Niels; Lund, Bente; Bergfeldt, Kjell; Wihl, Jessica; Keldsen, Nina; Marth, Christian; Vergote, Ignace; Jakobsen, Anders

    2013-01-01

    The increasing number of negative trials for ovarian cancer treatment has prompted an evaluation of new biologic agents, which in combination with chemotherapy may improve survival. The aim of this study was to investigate the response rate in platinum-resistant, KRAS wild-type ovarian cancer patients treated with pegylated liposomal doxorubicin (PLD) supplemented with panitumumab. Major eligibility criteria were relapsed ovarian/fallopian/peritoneal cancer patients with platinum-resistant disease, measurable disease by GCIG CA125 criteria and KRAS wild-type. Patients were treated with panitumumab 6 mg/kg day 1 and day 15 and with PLD 40 mg/m2 day 1, every 4 weeks. Forty-six patients were enrolled by 6 study sites in this multi-institutional phase II trial. The response rate in the intention-to-treat population (n = 43) was 18.6%. Progression-free and overall survival in the intention-to-treat population was 2.7 months (2.5-3.2 months, 95% confidence interval) and 8.1 months (5.6-11.7 months, 95% confidence interval), respectively. The most common treatment-related grade 3 toxicities included skin toxicity (42%), fatigue (19%), and vomiting (12%). The combination of PLD and panitumumab demonstrates efficacy in platinum refractory/resistant patients but the skin toxicity was considerable.

  10. Experimental studies of tearing mode and resistive wall mode dynamics in the reversed field pinch configuration

    Energy Technology Data Exchange (ETDEWEB)

    Malmberg, Jenny-Ann

    2003-06-01

    It is relatively straightforward to establish equilibrium in magnetically confined plasmas, but the plasma is frequently susceptible to a variety of instabilities that are driven by the free energy in the magnetic field or in the pressure gradient. These unstable modes exhibit effects that affect the particle, momentum and heat confinement properties of the configuration. Studies of the dynamics of several of the most important modes are the subject of this thesis. The studies are carried out on plasmas in the reversed field pinch (RFP) configuration. One phenomenon commonly observed in RFPs is mode wall locking. The localized nature of these phase- and wall locked structures results in localized power loads on the wall which are detrimental for confinement. A detailed study of the wall locked mode phenomenon is performed based on magnetic measurements from three RFP devices. The two possible mechanisms for wall locking are investigated. Locking as a result of tearing modes interacting with a static field error and locking due to the presence of a non-ideal boundary. The characteristics of the wall locked mode are qualitatively similar in a device with a conducting shell system (TPE-RX) compared to a device with a resistive shell (Extrap T2). A theoretical model is used for evaluating the threshold values for wall locking due to eddy currents in the vacuum vessel in these devices. A good correlation with experiment is observed for the conducting shell device. The possibility of successfully sustaining discharges in a resistive shell RFP is introduced in the recently rebuilt device Extrap T2R. Fast spontaneous mode rotation is observed, resulting in low magnetic fluctuations, low loop voltage and improved confinement. Wall locking is rarely observed. The low tearing mode amplitudes allow for the theoretically predicted internal non-resonant on-axis resistive wall modes to be observed. These modes have not previously been distinguished due to the formation of wall

  11. Novel 5-oxo-hexahydroquinoline derivatives: design, synthesis, in vitro P-glycoprotein-mediated multidrug resistance reversal profile and molecular dynamics simulation study.

    Science.gov (United States)

    Shahraki, Omolbanin; Edraki, Najmeh; Khoshneviszadeh, Mehdi; Zargari, Farshid; Ranjbar, Sara; Saso, Luciano; Firuzi, Omidreza; Miri, Ramin

    2017-01-01

    Overexpression of the efflux pump P-glycoprotein (P-gp) is one of the important mechanisms of multidrug resistance (MDR) in many tumor cells. In this study, 26 novel 5-oxo-hexahydroquinoline derivatives containing different nitrophenyl moieties at C4 and various carboxamide substituents at C3 were designed, synthesized and evaluated for their ability to inhibit P-gp by measuring the amount of rhodamine 123 (Rh123) accumulation in uterine sarcoma cells that overexpress P-gp (MES-SA/Dx5) using flow cytometry. The effect of compounds with highest MDR reversal activities was further evaluated by measuring the alterations of MES-SA/Dx5 cells' sensitivity to doxorubicin (DXR) using MTT assay. The results of both biological assays indicated that compounds bearing 2-nitrophenyl at C4 position and compounds with 4-chlorophenyl carboxamide at C3 demonstrated the highest activities in resistant cells, while they were devoid of any effect in parental nonresistant MES-SA cells. One of the active derivatives, 5c, significantly increased intracellular Rh123 at 100 µM, and it also significantly reduced the IC50 of DXR by 70.1% and 88.7% at 10 and 25 µM, respectively, in MES-SA/Dx5 cells. The toxicity of synthesized compounds against HEK293 as a noncancer cell line was also investigated. All tested derivatives except for 2c compound showed no cytotoxicity. A molecular dynamics simulation study was also performed to investigate the possible binding site of 5c in complex with human P-gp, which showed that this compound formed 11 average H-bonds with Ser909, Thr911, Arg547, Arg543 and Ser474 residues of P-gp. A good agreement was found between the results of the computational and experimental studies. The findings of this study show that some 5-oxo-hexahydroquinoline derivatives could serve as promising candidates for the discovery of new agents for P-gp-mediated MDR reversal.

  12. Natural alkaloids as P-gp inhibitors for multidrug resistance reversal in cancer.

    Science.gov (United States)

    Joshi, Prashant; Vishwakarma, Ram A; Bharate, Sandip B

    2017-09-29

    The biggest challenge associated with cancer chemotherapy is the development of cross multi-drug resistance to almost all anti-cancer agents upon chronic treatment. The major contributing factor for this resistance is efflux of the drugs by the p-glycoprotein pump. Over the years, inhibitors of this pump have been discovered to administer them in combination with chemotherapeutic agents. The clinical failure of first and second generation P-gp inhibitors (such as verapamil and cyclosporine analogs) has led to the discovery of third generation potent P-gp inhibitors (tariquidar, zosuquidar, laniquidar). Most of these inhibitors are nitrogenous compounds and recently a natural alkaloid CBT-01 ® (tetrandrine) has advanced to the clinical phase. CBT-01 demonstrated positive results in Phase-I study in combination with paclitaxel, which warranted conducting it's Phase II/III trial. Apart from this, there exist a large number of natural alkaloids possessing potent inhibition of P-gp efflux pump and other related pumps responsible for the development of resistance. Despite the extensive contribution of alkaloids in this area, has never been reviewed. The present review provides a comprehensive account on natural alkaloids possessing P-gp inhibition activity and their potential for multidrug resistance reversal in cancer. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  13. Reversal of multidrug resistance by morning glory resin glycosides in human breast cancer cells.

    Science.gov (United States)

    Figueroa-González, Gabriela; Jacobo-Herrera, Nadia; Zentella-Dehesa, Alejandro; Pereda-Miranda, Rogelio

    2012-01-27

    Reversal of multidrug resistance (MDR) by thirty resin glycosides from the morning glory family (Convolvulaceae) was evaluated in vinblastine-resistant human breast carcinoma cells (MCF-7/Vin). The effects of these amphipathic compounds on the cytotoxicity and P-glycoprotein (P-gp)-mediated MDR were estimated with the sulforhodamine B colorimetric assay. Active noncytotoxic compounds exerted a potentiation effect of vinblastine susceptibility by 1- to over 1906-fold at tested concentrations of 5 and 25 μg/mL. Murucoidin V (1) enhanced vinblastine activity 255-fold when incorporated at 25 μg/mL and also, based on flow cytometry, significantly increased the intracellular accumulation of rhodamine 123 with the use of reserpine as a positive control for a MDR reversal agent. Incubation of MCF-7/Vin cells with 1 caused an increase in uptake and notably lowered the efflux rate of rhodamine 123. Decreased expression of P-glycoprotein by compound 1 was detected by immunofluorescence flow cytometry after incubation with an anti-P-gp monoclonal antibody. These results suggest that resin glycosides represent potential efflux pump inhibitors for overcoming MDR in cancer therapy.

  14. Reversion of pH-induced physiological drug resistance: a novel function of copolymeric nanoparticles.

    Directory of Open Access Journals (Sweden)

    Rutian Li

    Full Text Available AIMS: The extracellular pH of cancer cells is lower than the intracellular pH. Weakly basic anticancer drugs will be protonated extracellularly and display a decreased intracellular concentration. In this study, we show that copolymeric nanoparticles (NPs are able to overcome this "pH-induced physiological drug resistance" (PIPDR by delivering drugs to the cancer cells via endocytosis rather than passive diffussion. MATERIALS AND METHODS: As a model nanoparticle, Tetradrine (Tet, Pka 7.80 was incorporated into mPEG-PCL. The effectiveness of free Tet and Tet-NPs were compared at different extracellular pHs (pH values 6.8 and 7.4, respectively by MTT assay, morphological observation and apoptotic analysis in vitro and on a murine model by tumor volume measurement, PET-CT scanning and side effect evaluation in vivo. RESULTS: The cytotoxicity of free Tet decreased prominently (P<0.05 when the extracellular pH decreased from 7.4 to 6.8. Meanwhile, the cytotoxicity of Tet-NPs was not significantly influenced by reduced pH. In vivo experiment also revealed that Tet-NPs reversed PIPDR more effectively than other existing methods and with much less side effects. CONCLUSION: The reversion of PIPDR is a new discovered mechanism of copolymeric NPs. This study emphasized the importance of cancer microenvironmental factors in anticancer drug resistance and revealed the superiority of nanoscale drug carrier from a different aspect.

  15. Reversible and adaptive resistance to BRAF(V600E) inhibition in melanoma

    Science.gov (United States)

    Sun, Chong; Wang, Liqin; Huang, Sidong; Heynen, Guus J. J. E.; Prahallad, Anirudh; Robert, Caroline; Haanen, John; Blank, Christian; Wesseling, Jelle; Willems, Stefan M.; Zecchin, Davide; Hobor, Sebastijan; Bajpe, Prashanth K.; Lieftink, Cor; Mateus, Christina; Vagner, Stephan; Grernrum, Wipawadee; Hofland, Ingrid; Schlicker, Andreas; Wessels, Lodewyk F. A.; Beijersbergen, Roderick L.; Bardelli, Alberto; di Nicolantonio, Federica; Eggermont, Alexander M. M.; Bernards, Rene

    2014-04-01

    Treatment of BRAF(V600E) mutant melanoma by small molecule drugs that target the BRAF or MEK kinases can be effective, but resistance develops invariably. In contrast, colon cancers that harbour the same BRAF(V600E) mutation are intrinsically resistant to BRAF inhibitors, due to feedback activation of the epidermal growth factor receptor (EGFR). Here we show that 6 out of 16 melanoma tumours analysed acquired EGFR expression after the development of resistance to BRAF or MEK inhibitors. Using a chromatin-regulator-focused short hairpin RNA (shRNA) library, we find that suppression of sex determining region Y-box 10 (SOX10) in melanoma causes activation of TGF-β signalling, thus leading to upregulation of EGFR and platelet-derived growth factor receptor-β (PDGFRB), which confer resistance to BRAF and MEK inhibitors. Expression of EGFR in melanoma or treatment with TGF-β results in a slow-growth phenotype with cells displaying hallmarks of oncogene-induced senescence. However, EGFR expression or exposure to TGF-β becomes beneficial for proliferation in the presence of BRAF or MEK inhibitors. In a heterogeneous population of melanoma cells having varying levels of SOX10 suppression, cells with low SOX10 and consequently high EGFR expression are rapidly enriched in the presence of drug, but this is reversed when the drug treatment is discontinued. We find evidence for SOX10 loss and/or activation of TGF-β signalling in 4 of the 6 EGFR-positive drug-resistant melanoma patient samples. Our findings provide a rationale for why some BRAF or MEK inhibitor-resistant melanoma patients may regain sensitivity to these drugs after a `drug holiday' and identify patients with EGFR-positive melanoma as a group that may benefit from re-treatment after a drug holiday.

  16. Hydrophilic, bactericidal nanoheater-enabled reverse osmosis membranes to improve fouling resistance.

    Science.gov (United States)

    Ray, Jessica R; Tadepalli, Sirimuvva; Nergiz, Saide Z; Liu, Keng-Ku; You, Le; Tang, Yinjie; Singamaneni, Srikanth; Jun, Young-Shin

    2015-06-03

    Polyamide (PA) semipermeable membranes typically used for reverse osmosis water treatment processes are prone to fouling, which reduces the amount and quality of water produced. By synergistically coupling the photothermal and bactericidal properties of graphene oxide (GO) nanosheets, gold nanostars (AuNS), and hydrophilic polyethylene glycol (PEG) on PA reverse osmosis membrane surfaces, we have dramatically improved fouling resistance of these membranes. Batch fouling experiments from three classes of fouling are presented: mineral scaling (CaCO3 and CaSO4), organic fouling (humic acid), and biofouling (Escherichia coli). Systematic analyses and a variety of complementary techniques were used to elucidate fouling resistance mechanisms from each layer of modification on the membrane surface. Both mineral scaling and organic fouling were significantly reduced in PA-GO-AuNS-PEG membranes compared to other membranes. The PA-GO-AuNS-PEG membrane was also effective in killing all near-surface bacteria compared to PA membranes. In the PA-GO-AuNS-PEG membrane, the GO nanosheets act as templates for in situ AuNS growth, which then facilitated localized heating upon irradiation by an 808 nm laser inactivating bacteria on the membrane surface. Furthermore, AuNS in the membrane assisted PEG in preventing mineral scaling on the membrane surface. In flow-through flux and foulant rejection tests, PA-GO-AuNS-PEG membranes performed better than PA membranes in the presence of CaSO4 and humic acid model foulants. Therefore, the newly suggested membrane surface modifications will not only reduce fouling from RO feeds, but can improve overall membrane performance. Our innovative membrane design reported in this study can significantly extend the lifetime and water treatment efficacy of reverse osmosis membranes to alleviate escalating global water shortage from rising energy demands.

  17. The new cardioprotector Monohydroxyethylrutoside protects against doxorubicin-induced inflammatory effects in vitro.

    Science.gov (United States)

    Abou El Hassan, M A I; Verheul, H M W; Jorna, A S; Schalkwijk, C; van Bezu, J; van der Vijgh, W J F; Bast, A

    2003-07-21

    Besides its cardiotoxic effect, doxorubicin also elicits inflammatory effects in vivo. 7-Monohydroxyethylrutoside (monoHER) has recently been used as a protector against doxorubicin-induced cardiotoxicity in vivo. It is not known yet whether monoHER can also protect against doxorubicin-induced inflammatory effects. The aim of the present study was (1) to illustrate the inflammatory effects of doxorubicin in vitro and (2) to evaluate a possibly protective effect of monoHER. In order to demonstrate the inflammatory effects of doxorubicin and the possible protection of monoHER, proliferating human umbilical cord vascular endothelial cells (HUVECs) were incubated with different concentrations of doxorubicin ranging from 12.5 to 600 nM with(out) 200 micro M monoHER. Resting (confluent) HUVECs were incubated with (0.5-25 micro M) doxorubicin with(out) monoHER (0.2-1.2 mM) and the viability of endothelial cells and their propensity to adhere to neutrophils were measured 24 h after treatment. The localisation of adhered neutrophils was determined with immunofluorescence microscopy. To further characterise the mechanism of doxorubicin-induced neutrophil adhesion, the expression of the HUVECs surface adhesion molecules was determined after doxorubicin treatment. Doxorubicin decreased the viability and proliferation capacity of HUVECs in a concentration-dependent manner. The proliferating HUVECs were much more sensitive to doxorubicin (IC(50)=60.0+/-20.8 nM) than resting cells (LC(50)=4.0+/-0.3 micro M). Doxorubicin also increased the adhesion of neutrophils reaching a plateau value at a doxorubicin concentration of > or =0.4 micro M (P=0.0113). The induced neutrophil adhesion was accompanied by overexpression of VCAM and E-selectin but not ICAM. Although monoHER did not reverse the effect of doxorubicin on the proliferation of endothelial cells, it significantly protected resting HUVECs against the cytotoxic effect of doxorubicin (inflammatory effects. These data prompt

  18. Evaluation of 4-thiazolidinone derivatives as potential reverse transcriptase inhibitors against HIV-1 drug resistant strains.

    Science.gov (United States)

    Suryawanshi, Rahul; Jadhav, Sushama; Makwana, Nandini; Desai, Dipen; Chaturbhuj, Devidas; Sonawani, Archana; Idicula-Thomas, Susan; Murugesan, Vanangamudi; Katti, Seturam B; Tripathy, Srikanth; Paranjape, Ramesh; Kulkarni, Smita

    2017-04-01

    Rapid emergence of drug resistance is crucial in management of HIV infection limiting implementation of efficacious drugs in the ART regimen. Designing new molecules against HIV drug resistant strains is utmost essential. Based on the anti-HIV-1 activity, we selected four 4-thiazolidinone derivatives (S009-1908, S009-1909, S009-1911, S009-1912) and studied their interaction with reverse transcriptase (RT) from a panel of 10 clinical isolates (8 nevirapine resistant and two susceptible) using in silico methods, and inhibition pattern using in vitro cell based assays. On the basis of binding affinity observed in in silico analysis, 2-(2-chloro-6-nitrophenyl)-3-(4, 6-dimethylpyridin-2-yl) thiazolidin-4-one (S009-1912) was identified as the lead molecule followed by S009-1908, S009-1909 and S009-1911. The in vitro activity against the same panel was assessed using TZM-bl assay (IC50: 0.4-11.44µg/ml, TI: 4-126) and subsequently in PBMC assay against a nevirapine resistant clinical isolate (IC50: 0.8-6.65µg/ml, TI: 8.31-11.43) and standard strain from NIH ARRRP (IC50: 0.95-3.6µg/ml, TI: 9-26). The study shows analogue with pyrimidin-2-yl amino substitution at N-3 position of thiazolidin-4-one ring (S009-1908, S009-1909, S009-1911) exhibited enhanced activity as compared to pyridin-2-yl substituted derivatives (S009-1912), suggesting the use 4-thiazolidinones for developing potent inhibitors against HIV-1 drug resistant strains. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Drug Resistance in Non-B Subtype HIV-1: Impact of HIV-1 Reverse Transcriptase Inhibitors

    Directory of Open Access Journals (Sweden)

    Kamalendra Singh

    2014-09-01

    Full Text Available Human immunodeficiency virus (HIV causes approximately 2.5 million new infections every year, and nearly 1.6 million patients succumb to HIV each year. Several factors, including cross-species transmission and error-prone replication have resulted in extraordinary genetic diversity of HIV groups. One of these groups, known as group M (main contains nine subtypes (A-D, F-H and J-K and causes ~95% of all HIV infections. Most reported data on susceptibility and resistance to anti-HIV therapies are from subtype B HIV infections, which are prevalent in developed countries but account for only ~12% of all global HIV infections, whereas non-B subtype HIV infections that account for ~88% of all HIV infections are prevalent primarily in low and middle-income countries. Although the treatments for subtype B infections are generally effective against non-B subtype infections, there are differences in response to therapies. Here, we review how polymorphisms, transmission efficiency of drug-resistant strains, and differences in genetic barrier for drug resistance can differentially alter the response to reverse transcriptase-targeting therapies in various subtypes.

  20. Induction and reversibility of insulin resistance in rats exposed to exogenous D-fructose.

    Science.gov (United States)

    Cancelas, J; Prieto, P G; García-Arévalo, M; Sancho, V; Villanueva-Peñacarrillo, M L; Malaisse, W J; Valverde, I

    2008-07-01

    Long-term exposure of normal rats to a fructose-enriched diet or drinking water is currently used as an animal model for experimental insulin resistance. The present study deals with a comparison between rats given access to either a fructose-enriched diet or fructose-enriched drinking water. In both situations, a decrease in food intake and body weight gain, and the induction of insulin resistance with intolerance to D-glucose despite increased secretory response to the aldohexose of insulin-producing cells were documented. Moreover, the rats exposed to exogenous D-fructose displayed a lesser sensitivity to overnight fasting than control animals, in terms of the alteration of glucose homeostasis and reduction of the ratio between plasma insulin and D-glucose concentration. It is also shown that the fructose-induced insulin resistance, as assessed in a hyperinsulinemic-euglycemic clamp, represents a phenomenon reversed within 15-30 days after removal of the keto-hexose from the drinking water.

  1. Merremins A-G, resin glycosides from Merremia hederacea with multidrug resistance reversal activity.

    Science.gov (United States)

    Wang, Wen-qiong; Song, Wei-bin; Lan, Xiao-jing; Huang, Min; Xuan, Li-jiang

    2014-10-24

    Five new pentasaccharide resin glycosides, named merremins A-E (1-5), two new pentasaccharide resin glycoside methyl esters, named merremins F and G (6, 7), and four known resin glycosides, murucoidin IV, murucoidin V, stoloniferin IV, and murucoidin XVII, were obtained from the aerial parts of Merremia hederacea. This is the first report of resin glycosides obtained from M. hederacea. In addition, the new compounds can be divided into three types: those possessing an 18-membered ring (1-4), compound 5 with a 20-membered ring, and those with an acyclic core (6, 7). Furthermore, the different types of resin glycosides were evaluated for their multidrug resistance reversal activities. Compounds 1, 5, 6, and murucoidin V were noncytotoxic and enhanced the cytotoxicity of vinblastine by 2.3-142.5-fold at 25 μM. Compound 5 and murucoidin V, with 20-membered rings, were more active than compound 1, with an 18-membered ring.

  2. Resistive wall modes in the EXTRAP T2R reversed-field pinch

    Science.gov (United States)

    Brunsell, P. R.; Malmberg, J.-A.; Yadikin, D.; Cecconello, M.

    2003-10-01

    Resistive wall modes (RWM) in the reversed field pinch are studied and a detailed comparison of experimental growth rates and linear magnetohydrodynamic (MHD) theory is made. RWM growth rates are experimentally measured in the thin shell device EXTRAP T2R [P. R. Brunsell et al., Plasma Phys. Controlled Fusion 43, 1 (2001)]. Linear MHD calculations of RWM growth rates are based on experimental equilibria. Experimental and linear MHD RWM growth rate dependency on the equilibrium profiles is investigated experimentally by varying the pinch parameter Θ=Bθ(a)/ in the range Θ=1.5-1.8. Quantitative agreement between experimental and linear MHD growth rates is seen. The dominating RWMs are the internal on-axis modes (having the same helicity as the central equilibrium field). At high Θ, external nonresonant modes are also observed. For internal modes experimental growth rates decrease with Θ while for external modes, growth rates increase with Θ. The effect of RWMs on the reversed-field pinch plasma performance is discussed.

  3. Conditioned Media From Adipose Tissue Derived Mesenchymal Stem Cells Reverse Insulin Resistance in Cellular Models.

    Science.gov (United States)

    Shree, Nitya; Bhonde, Ramesh R

    2017-08-01

    The link between insulin resistance (IR) and type 2 diabetes has been recognized for a long time. Type 2 diabetes is often associated with basal hyperinsulinemia, reduced sensitivity to insulin, and disturbances in insulin release. There are evidences showing the reversal of IR by mesenchymal stem cells. However, the effect of conditioned media from adipose derived mesenchymal stem cells (ADSCs-CM) in reversal of IR has not been established. We established an insulin resistant model of 3T3L1 and C2C12 cells and treated with ADSCs-CM. 2-NBDG (2-[N-[7-Nitrobenz-2-oxa-1,3-diazol-4-yl]Amino]-2-Deoxyglucose) uptake was performed to assess improvement in glucose uptake. Genes involved in glucose transport and in inflammation were also analysed. Western blot for glucose transporter-4 and Akt was performed to evaluate translocation of Glut4 and insulin signaling respectively. We found that the ADSCs-CM treated cells restored insulin, stimulated glucose uptake as compared to the untreated control indicating the insulin sensitizing effect of the CM. The treated cells also showed inhibition adipogenesis in 3T3L1 cells and significant reduction of intramuscular triglyceride accumulation in C2C12 cells. Gene expressions studies revealed the drastic upregulation of GLUT4 gene and significant reduction in IL6 and PAI1 gene in both 3T3L1 and C2C12 cells, indicating possible mechanism of glucose uptake with concomitant decrease in inflammation. Enhancement of GLUT4 and phospho Akt protein expression seems to be responsible for the increment in glucose uptake and enhanced insulin signaling, respectively. Our study revealed for the first time that ADSCs-CM acts as an alternative insulin sensitizer providing stem cell solution to IR. J. Cell. Biochem. 118: 2037-2043,2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  4. Extracellular Matrix Proteins Modulate Antimigratory and Apoptotic Effects of Doxorubicin

    Directory of Open Access Journals (Sweden)

    Georges Said

    2012-01-01

    Full Text Available Anticancer drug resistance is a multifactorial process that includes acquired and de novo drug resistances. Acquired resistance develops during treatment, while de novo resistance is the primary way for tumor cells to escape chemotherapy. Tumor microenvironment has been recently shown to be one of the important factors contributing to de novo resistance and called environment-mediated drug resistance (EMDR. Two forms of EMDR have been described: soluble factor-mediated drug resistance (SFM-DR and cell adhesion-mediated drug resistance (CAM-DR. Anthracyclines, among the most potent chemotherapeutic agents, are widely used in clinics against hematopoietic and solid tumors. Their main mechanism of action relies on the inhibition of topoisomerase I and/or II and the induction of apoptosis. Beyond this well-known antitumor activity, it has been recently demonstrated that anthracyclines may display potent anti-invasive effects when used at subtoxic concentrations. In this paper, we will describe two particular modes of EMDR by which microenvironment may influence tumor-cell response to one of these anthracyclines, doxorubicin. The first one considers the influence of type I collagen on the antimigratory effect of doxorubicin (CAM-DR. The second considers the protection of tumor cells by thrombospondin-I against doxorubicin-induced apoptosis (SFM-DR.

  5. Doxorubicin-loaded NaYF4:Yb/Tm-TiO2 inorganic photosensitizers for NIR-triggered photodynamic therapy and enhanced chemotherapy in drug-resistant breast cancers.

    Science.gov (United States)

    Zeng, Leyong; Pan, Yuanwei; Tian, Ying; Wang, Xin; Ren, Wenzhi; Wang, Shouju; Lu, Guangming; Wu, Aiguo

    2015-07-01

    The combination therapy has exhibited important potential for the treatment of cancers, especially for drug-resistant cancers. In this report, bi-functional nanoprobes based on doxorubicin (DOX)-loaded NaYF4:Yb/Tm-TiO2 inorganic photosensitizers (FA-NPs-DOX) were synthesized for in vivo near infrared (NIR)-triggered inorganic photodynamic therapy (PDT) and enhanced chemotherapy to overcome the multidrug resistance (MDR) in breast cancers. Using the up-conversion luminescence (UCL) performance of NaYF4:Yb/Tm converting near-infrared (NIR) into ultraviolent (UV) lights, reactive oxygen species (ROS) were triggered from TiO2 inorganic photosensitizers for PDT under the irradiation of a 980 nm laser, by which the deep-penetration and low photo-damage could be reached. Moreover, nanocarrier delivery and folic acid (FA) targeting promoted the cellular uptake, and accelerated the release of DOX in drug-sensitive MCF-7 and resistant MCF-7/ADR cells. The toxicity assessment in vitro and in vivo revealed the good biocompatibility of the as-prepared FA-NPs-DOX nanocomposites. By the combination of enhanced chemotherapy and NIR-triggered inorganic PDT, the viability of MCF-7/ADR cells could decrease by 53.5%, and the inhibition rate of MCF-7/ADR tumors could increase up to 90.33%, compared with free DOX. Therefore, the MDR of breast cancers could be obviously overcome by enhanced chemotherapy and NIR-triggered inorganic PDT of FA-NPs-DOX nanocomposites under the excitation of a 980 nm laser. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Quantitative plasma spectroscopy in a resistive shell reversed-field pinch

    Energy Technology Data Exchange (ETDEWEB)

    Hedqvist, Anders

    1999-10-01

    The subject addressed in this thesis is quantitative plasma spectroscopy. Measurements of electron temperature and impurity ion density, performed at EXTRAP-T2, are aimed to investigate the effects of operating a reversed- field pinch with a resistive shell and a graphite wall. The spectroscopic measurements are analyzed with a collisional-radiative model and a consistency check is performed for the measurements and the model itself. The resistive shell results in wall-locked modes, enhanced plasma-wall interaction and degraded confinement. Measurements of vacuum ultraviolet resonant transitions of carbon and oxygen show that the local heating of the wall, at the position of the locking, leads to influxes of hydrogen and impurities, resulting in a cold and resistive plasma. Effects on the local scale are also observed. Spatially-resolved measurements of line emission originating from charge exchange collisions are used to investigate the change in neutral hydrogen profile. Temporal correlations between soft x-ray emission and poloidal loop voltage at the position of the wall-locked modes are observed and in connection, a decrease in central electron temperature, indicating there is a direct energy loss channel between the center and the edge. The hydrogen recycling properties of the graphite wall are investigated in an isotope exchange experiment. The density of the hydrogen isotopes are measured from spectral line emission and compared with recycling models. In charge exchange collisions between fully stripped chlorine and thermal deuterium, observed in JET plasmas, only a single n-level is populated. This is different from most ions and may be used to test models for calculating charge exchange collision cross-sections.

  7. [Reversal of stemness in multidrug-resistant hepatocellular carcinoma cells by SIS3].

    Science.gov (United States)

    Yan, Wei; Wen, Ting; Lin, Suqiong; Liu, Zhongcai; Yang, Wenchao; Wu, Guoyang

    2015-10-01

    To investigate whether SIS3, a specific inhibitor of Smad3 phosphorylation, can reverse the stemness of multidrug-resistant(MDR) hepatocellular carcinoma cells. MDR HCC Huh7.5.1/ADM cell lines were developed by exposing parental cells to stepwise increasing concentrations of ADM. CCK-8 assay was used to determine the cellular sensitivity of various anticancer drugs. Flow cytometry (FCM) was used to analyze the expression level of cancer stem cell marker CD133. Clone formation assay and mouse subcutaneous xenograft tumors were used to investigate the tumorigenicity in vitro and in vivo. Western blotting (WB) was used to analyze the changes of expressions of CD133, Smad3, Bcl-2, Bax and p-Smad3 in different conditions. ADM treatment of HCC cells in vitro resulted in a development of subline, Huh7.5.1/ADM cells, with CSC phenotypes: stable MDR phenotype (besides ADMc Huh7.5.1/ADM cells were also more resistant to some other anticancer drugs including VCR, MMC and CTX ) (IC50: 0.215 ± 0.018 vs. 0.123 ± 0.004, 0.145 ± 0.009 vs. 0.014 ± 0.002, 1.021 ± 0.119 vs. 0.071 ± 0.006, 27.007 ± 1.606 vs. 1.919 ± 0.032) (unit: µg/ml) (Punit: µg/ml) (P<0.05), and decreased tumorigenicity and colony formation ability. SIS3 as a specific inhibitor of Smad3 signal is involved in the stemness of multidrug resistant hepatocellular carcinoma cells.

  8. The rate of accumulation of nonnucleoside reverse transcriptase inhibitor (NNRTI) resistance in patients kept on a virologically failing regimen containing an NNRTI*

    DEFF Research Database (Denmark)

    Cozzi-Lepri, A; Paredes, R; Phillips, A N

    2012-01-01

    Virological failure of first-generation nonnucleoside reverse transcriptase inhibitors (NNRTIs) can compromise the efficacy of etravirine as a result of the accumulation of NNRTI resistance mutations. How quickly NNRTI resistance accumulates in patients with a delayed switch from nevirapine...

  9. Compound list: doxorubicin [Open TG-GATEs

    Lifescience Database Archive (English)

    Full Text Available doxorubicin DOX 00149 ftp://ftp.biosciencedbc.jp/archive/open-tggates/LATEST/Human/in_vitro/doxorubicin....Human.in_vitro.Liver.zip ftp://ftp.biosciencedbc.jp/archive/open-tggates/LATEST/Rat/in_vitro/doxorubicin....Rat.in_vitro.Liver.zip ftp://ftp.biosciencedbc.jp/archive/open-tggates/LATEST/Rat/in_vivo/Liver/Single/doxorubicin...archive/open-tggates/LATEST/Rat/in_vivo/Liver/Repeat/doxorubicin.Rat.in_vivo.Liver.Repeat.zip ftp://ftp.bios...ciencedbc.jp/archive/open-tggates/LATEST/Rat/in_vivo/Kidney/Single/doxorubicin.Rat.in_vivo.Kidney.Single.zip

  10. Development of elvitegravir resistance and linkage of integrase inhibitor mutations with protease and reverse transcriptase resistance mutations.

    Directory of Open Access Journals (Sweden)

    Mark A Winters

    Full Text Available Failure of antiretroviral regimens containing elvitegravir (EVG and raltegravir (RAL can result in the appearance of integrase inhibitor (INI drug-resistance mutations (DRMs. While several INI DRMs have been identified, the evolution of EVG DRMs and the linkage of these DRMs with protease inhibitor (PI and reverse transcriptase inhibitor (RTI DRMs have not been studied at the clonal level. We examined the development of INI DRMs in 10 patients failing EVG-containing regimens over time, and the linkage of INI DRMs with PI and RTI DRMs in these patients plus 6 RAL-treated patients. A one-step RT-nested PCR protocol was used to generate a 2.7 kB amplicon that included the PR, RT, and IN coding region, and standard cloning and sequencing techniques were used to determine DRMs in 1,277 clones (mean 21 clones per time point. Results showed all patients had multiple PI, NRTI, and/or NNRTI DRMs at baseline, but no primary INI DRM. EVG-treated patients developed from 2 to 6 strains with different primary INI DRMs as early as 2 weeks after initiation of treatment, predominantly as single mutations. The prevalence of these strains fluctuated and new strains, and/or strains with new combinations of INI DRMs, developed over time. Final failure samples (weeks 14 to 48 typically showed a dominant strain with multiple mutations or N155H alone. Single N155H or multiple mutations were also observed in RAL-treated patients at virologic failure. All patient strains showed evidence of INI DRM co-located with single or multiple PI and/or RTI DRMs on the same viral strand. Our study shows that EVG treatment can select for a number of distinct INI-resistant strains whose prevalence fluctuates over time. Continued appearance of new INI DRMs after initial INI failure suggests a potent, highly dynamic selection of INI resistant strains that is unaffected by co-location with PI and RTI DRMs.

  11. Phorbol esters induce multidrug resistance in human breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Fine, R.L.; Patel, J.; Chabner, B.A.

    1988-01-01

    Mechanisms responsible for broad-based resistance to antitumor drugs derived from natural products (multidrug resistance) are incompletely understood. Agents known to reverse the multidrug-resistant phenotype (verapamil and trifluoperazine) can also inhibit the activity of protein kinase C. When the authors assayed human breast cancer cell lines for protein kinase C activity, they found that enzyme activity was 7-fold higher in the multidrug-resistance cancer cells compared with the control, sensitive parent cells. Exposure of drug-sensitive cells to the phorbol ester phorbol 12,13-dibutyate (P(BtO)/sub 2/) led to an increase in protein kinase C activity and induced a drug-resistance phenotype, whereas exposure of drug-resistant cells to P(BtO)/sub 2/ further increased drug resistance. In sensitive cells, this increased resistance was accomplished by a 3.5-fold increased phosphorylation of a 20-kDa particulate protein and a 35-40% decreased intracellular accumulation of doxorubicin and vincristine. P(BtO)/sub 2/ induced resistance to agents involved in the multidrug-resistant phenotype (doxorubicin and vincristine) but did not affect sensitivity to an unrelated alkylating agent (melphalan). The increased resistance was partially or fully reversible by the calcium channel blocker verapamil and by the calmodulin-antagonist trifluoperazine. These data suggest that stimulation of protein kinase C playus a role in the drug-transport changes in multidrug-resistant cells. This may occur through modulation of an efflux pump by protein phosphorylation.

  12. A polyphenol-rich cranberry extract reverses insulin resistance and hepatic steatosis independently of body weight loss

    Directory of Open Access Journals (Sweden)

    Fernando F. Anhê

    2017-12-01

    Conclusions: Taken together, our findings demonstrate that CE, without impacting body weight or adiposity, can fully reverse HFHS diet-induced insulin resistance and hepatic steatosis while triggering A. muciniphila blooming in the gut microbiota, thus underscoring the gut-liver axis as a primary target of cranberry polyphenols.

  13. Impact Of A Uniform Plasma Resistivity In MHD Modelling Of Helical Solutions For The Reversed Field Pinch Dynamo

    CERN Document Server

    Bonfiglio, D; Escande, D F

    2016-01-01

    Till now the magnetohydrodynamic (MHD) simulation of the reversed field pinch (RFP) has been performed by assuming axis-symmetric radial time independent dissipation profiles. In helical states this assumption is not correct since these dissipations should be flux functions, and should exhibit a helical symmetry as well. Therefore more correct simulations should incorporate self-consistent dissipation profiles. As a first step in this direction, the case of uniform dissipation profiles was considered by using the 3D nonlinear visco-resistive MHD code SpeCyl. It is found that a flattening of the resistivity profile results in the reduction of the dynamo action, which brings to marginally-reversed or even non-reversed equilibrium solutions. The physical origin of this result is discussed in relation to the electrostatic drift explanation of the RFP dynamo. This sets constraints on the functional choice of dissipations in future self-consistent simulations.

  14. Randomized, open-label, phase III study comparing patupilone (EPO906) with pegylated liposomal doxorubicin in platinum-refractory or -resistant patients with recurrent epithelial ovarian, primary fallopian tube, or primary peritoneal cancer.

    Science.gov (United States)

    Colombo, Nicoletta; Kutarska, Elzbieta; Dimopoulos, Meletios; Bae, Duk-Soo; Rzepka-Gorska, Izabella; Bidzinski, Mariusz; Scambia, Giovanni; Engelholm, Svend Aage; Joly, Florence; Weber, Dirk; El-Hashimy, Mona; Li, Jingjin; Souami, Farida; Wing, Patricia; Engelholm, Silke; Bamias, Aristotelis; Schwartz, Peter

    2012-11-01

    This study compared the efficacy and safety of patupilone with those of pegylated liposomal doxorubicin (PLD) in patients with platinum-refractory or -resistant epithelial ovarian, primary fallopian tube, or primary peritoneal cancer. Patients with three or fewer prior regimens were eligible if they had received first-line taxane/platinum-based combination chemotherapy and were platinum refractory or resistant. Patients were randomly assigned to receive patupilone (10 mg/m(2) intravenously every 3 weeks) or PLD (50 mg/m(2) intravenously every 4 weeks). A total of 829 patients were randomly assigned (patupilone, n = 412; PLD, n = 417). There was no statistically significant difference in overall survival (OS), the primary end point, between the patupilone and PLD arms (P = .195; hazard ratio, 0.93; 95% CI, 0.79 to 1.09), with median OS rates of 13.2 and 12.7 months, respectively. Median progression-free survival was 3.7 months for both arms. The overall response rate (all partial responses) was higher in the patupilone arm than in the PLD arm (15.5% v 7.9%; odds ratio, 2.11; 95% CI, 1.36 to 3.29), although disease control rates were similar (59.5% v 56.3%, respectively). Frequently observed adverse events (AEs) of any grade included diarrhea (85.3%) and peripheral neuropathy (39.3%) in the patupilone arm and mucositis/stomatitis (43%) and hand-foot syndrome (41.8%) in the PLD arm. Patupilone did not demonstrate significant improvement in OS compared with the active control, PLD. No new or unexpected serious AEs were identified.

  15. A phase 1b study of trebananib in combination with pegylated liposomal doxorubicin or topotecan in women with recurrent platinum-resistant or partially platinum-sensitive ovarian cancer.

    Science.gov (United States)

    Vergote, Ignace; Schilder, Russell J; Pippitt, Charles H; Wong, Shirley; Gordon, Alan N; Scudder, Sidney; Kridelka, Frederic; Dirix, Luc; Leach, Joseph W; Ananda, Sumitra; Nanayakkara, Nuwan; Melara, Rebeca; Bass, Michael B; Litten, Jason; Adewoye, Henry; Wenham, Robert M

    2014-10-01

    To examine the tolerability and antitumor activity of trebananib plus pegylated liposomal doxorubicin (PLD) or topotecan in recurrent platinum-resistant or partially platinum-sensitive ovarian cancer. In this open-label phase 1b study, patients received trebananib 10 mg/kg or 15 mg/kg IV QW plus PLD 50 mg/m(2) (cohorts A1 and A3, respectively) or topotecan 4 mg/m(2) (cohorts B1 and B3, respectively). Endpoints were dose-limiting toxicity (DLT; primary); treatment-emergent adverse events (AEs), overall response rate, anti-trebananib antibodies, and pharmacokinetics (secondary). 103 patients were enrolled. One patient in A1 and B1 had DLTs. Across all cohorts, the most common AEs were nausea, fatigue, and peripheral edema. Across both trebananib plus PLD cohorts (A1/A3), grade 4 AEs were pulmonary embolism, disease progression, and anemia. Two patients had grade 5 intestinal perforation (n=1) and sudden death (n=1). Across both trebananib plus topotecan cohorts (B1/B3), grade 4 AEs were neutropenia, hypokalemia, decreased granulocyte count, chest pain, dyspnea, decreased neutrophil count, and pulmonary embolism. Two patients had grade 5 disease progression. One patient had grade 5 pleural effusion associated with progressive disease. Confirmed objective response rates were 36.0% (A1), 34.8% (A3), 16.7% (B1), and 0.0% (B3). Median progression-free survival duration (months) was 7.4 (A1), 7.1 (A3), 3.5 (B1), and 3.1 (B3), respectively. No drug-drug interactions were apparent. Trebananib 10mg/kg and 15 mg/kg IV QW plus PLD or topotecan appear to have acceptable toxicity profiles in recurrent platinum-resistant or partially platinum-sensitive ovarian cancer. Antitumor activity was evident across all cohorts. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Proteasome inhibition reverses hedgehog inhibitor and taxane resistance in ovarian cancer.

    Science.gov (United States)

    Steg, Adam D; Burke, Mata R; Amm, Hope M; Katre, Ashwini A; Dobbin, Zachary C; Jeong, Dae Hoon; Landen, Charles N

    2014-08-30

    The goal of this study was to determine whether combined targeted therapies, specifically those against the Notch, hedgehog and ubiquitin-proteasome pathways, could overcome ovarian cancer chemoresistance. Chemoresistant ovarian cancer cells were exposed to gamma-secretase inhibitors (GSI-I, Compound E) or the proteasome inhibitor bortezomib, alone and in combination with the hedgehog antagonist, LDE225. Bortezomib, alone and in combination with LDE225, was evaluated for effects on paclitaxel efficacy. Cell viability and cell cycle analysis were assessed by MTT assay and propidium iodide staining, respectively. Proteasome activity and gene expression were determined by luminescence assay and qPCR, respectively. Studies demonstrated that GSI-I, but not Compound E, inhibited proteasome activity, similar to bortezomib. Proteasome inhibition decreased hedgehog target genes (PTCH1, GLI1 and GLI2) and increased LDE225 sensitivity in vitro. Bortezomib, alone and in combination with LDE225, increased paclitaxel sensitivity through apoptosis and G2/M arrest. Expression of the multi-drug resistance gene ABCB1/MDR1 was decreased and acetylation of α-tubulin, a marker of microtubule stabilization, was increased following bortezomib treatment. HDAC6 inhibitor tubastatin-a demonstrated that microtubule effects are associated with hedgehog inhibition and sensitization to paclitaxel and LDE225. These results suggest that proteasome inhibition, through alteration of microtubule dynamics and hedgehog signaling, can reverse taxane-mediated chemoresistance.

  17. Reversible adaptive plasticity: A mechanism for neuroblastoma cell heterogeneity and chemo-resistance

    Directory of Open Access Journals (Sweden)

    Lina eChakrabarti

    2012-08-01

    Full Text Available We describe a novel form of tumor cell plasticity characterized by reversible adaptive plasticity in murine and human neuroblastoma. Two cellular phenotypes were defined by their ability to exhibit adhered, anchorage dependent (AD or sphere forming, anchorage independent (AI growth. The tumor cells could transition back and forth between the two phenotypes and the transition was dependent on the culture conditions. Both cell phenotypes exhibited stem-like features such as expression of nestin, self-renewal capacity and mesenchymal differentiation potential. The AI tumorspheres were found to be more resistant to chemotherapy and proliferated slower in vitro compared to the AD cells. Identification of specific molecular markers like MAP2, β-catenin and PDGFRβ enabled us to characterize and observe both phenotypes in established mouse tumors. Irrespective of the phenotype originally implanted in mice, tumors grown in vivo show phenotypic heterogeneity in molecular marker signatures and are indistinguishable in growth or histologic appearance. Similar molecular marker heterogeneity was demonstrated in primary human tumor specimens. Chemotherapy or growth factor receptor inhibition slowed tumor growth in mice and promoted initial loss of AD or AI heterogeneity, respectively. Simultaneous targeting of both phenotypes led to further tumor growth delay with emergence of new unique phenotypes. Our results demonstrate that neuroblastoma cells are plastic, dynamic and may optimize their ability to survive by changing their phenotype. Phenotypic switching appears to be an adaptive mechanism to unfavorable selection pressure and could explain the phenotypic and functional heterogeneity of neuroblastoma.

  18. Wear resistance of alloy вт-22 with non-ferrous alloys at reverse

    Directory of Open Access Journals (Sweden)

    А.М. Хімко

    2010-01-01

    Full Text Available  The article presents the results of tests of non hardened titanium alloy ВТ-22 with aviation non-ferrous alloys in reverse sliding friction. The main objective of the work is the selection of the optimum combination of materials depending on changes in loading conditions. Study of alloy ВТ-22 wear resistance was carried out in pairs with БрОФ-10-1, БрБ2, БрАЖ-9-4, ВТ-22, МЛ5, Д16Т, 7Х21ГАН5Ш and 95Х18Ш. The dependencies of the materials wear at pressures 10, 20 and 30 Mpa we determined. The linear nature of titanium alloy wear curves indicates that the change in the wear mechanism occurs gradually. The histograms of non-ferrous materials wear and the total wear of the friction pair are presented. It is established that the bronze БрАЖ-9-4 is the most preferable material for contact with non hardened titanium alloy ВТ-22, the least wear among the tested materials. The established coefficients of the titanium alloy ВТ-22 friction in pair with aviation structural non-ferrous alloys are presented. The results of research will be relevant for the engineering industry, where non hardened titanium alloy ВТ-22 in pair with non-ferrous alloys is applied.

  19. Grizzly bears exhibit augmented insulin sensitivity while obese prior to a reversible insulin resistance during hibernation.

    Science.gov (United States)

    Nelson, O Lynne; Jansen, Heiko T; Galbreath, Elizabeth; Morgenstern, Kurt; Gehring, Jamie Lauren; Rigano, Kimberly Scott; Lee, Jae; Gong, Jianhua; Shaywitz, Adam J; Vella, Chantal A; Robbins, Charles T; Corbit, Kevin C

    2014-08-05

    The confluence of obesity and diabetes as a worldwide epidemic necessitates the discovery of new therapies. Success in this endeavor requires translatable preclinical studies, which traditionally employ rodent models. As an alternative approach, we explored hibernation where obesity is a natural adaptation to survive months of fasting. Here we report that grizzly bears exhibit seasonal tripartite insulin responsiveness such that obese animals augment insulin sensitivity but only weeks later enter hibernation-specific insulin resistance (IR) and subsequently reinitiate responsiveness upon awakening. Preparation for hibernation is characterized by adiposity coupled to increased insulin sensitivity via modified PTEN/AKT signaling specifically in adipose tissue, suggesting a state of "healthy" obesity analogous to humans with PTEN haploinsufficiency. Collectively, we show that bears reversibly cope with homeostatic perturbations considered detrimental to humans and describe a mechanism whereby IR functions not as a late-stage metabolic adaptation to obesity, but rather a gatekeeper of the fed-fasting transition. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Expression profile of genes during resistance reversal in a temephos selected strain of the dengue vector, Aedes aegypti.

    Directory of Open Access Journals (Sweden)

    Clare Strode

    Full Text Available BACKGROUND: The mosquito Aedes aegypti is one of the most important disease vectors because it transmits two major arboviruses, dengue and yellow fever, which cause significant global morbidity and mortality. Chemical insecticides form the cornerstone of vector control. The organophosphate temephos a larvicide recommended by WHO for controlling Ae. aegypti, however, resistance to this compound has been reported in many countries, including Brazil. METHODOLOGY/PRINCIPAL FINDINGS: The aim of this study was to identify genes implicated in metabolic resistance in an Ae. aegypti temephos resistant strain, named RecR, through microarray analysis. We utilized a custom 'Ae. aegypti detox chip' and validated microarray data through RT-PCR comparing susceptible and resistant individuals. In addition, we analyzed gene expression in 4(th instar larvae from a reversed susceptible strain (RecRev, exposed and unexposed to temephos. The results obtained revealed a set of 13 and 6 genes significantly over expressed in resistant adult mosquitoes and larvae, respectively. One of these genes, the cytochrome P450 CYP6N12, was up-regulated in both stages. RT-PCR confirmed the microarray results and, additionally, showed no difference in gene expression between temephos exposed and unexposed RecRev mosquitoes. This suggested that the differences in the transcript profiles among the strains are heritable due to a selection process and are not caused by immediate insecticide exposure. Reversal of temephos resistance was demonstrated and, importantly, there was a positive correlation between a decrease in the resistance ratio and an accompanying decrease in the expression levels of previously over expressed genes. Some of the genes identified here have also been implicated in metabolic resistance in other mosquito species and insecticide resistant populations of Ae. aegypti. CONCLUSIONS/SIGNIFICANCE: The identification of gene expression signatures associated to

  1. Oxidative Stress Promotes Doxorubicin-Induced Pgp and BCRP Expression in Colon Cancer Cells Under Hypoxic Conditions.

    Science.gov (United States)

    Pinzón-Daza, Martha L; Cuellar-Saenz, Yenith; Nualart, Francisco; Ondo-Mendez, Alejandro; Del Riesgo, Lilia; Castillo-Rivera, Fabio; Garzón, Ruth

    2017-07-01

    P-glycoprotein (Pgp) and breast cancer resistance protein (BCRP) are ATP binding cassette (ABC) transporters that are overexpressed in different drug-resistant cancer cell lines. In this study, we investigated whether doxorubicin promotes Pgp and/or BCRP expression to induce drug resistance in colon cancer cells under hypoxic conditions. We analyzed HIF-1α activity via ELISA, Pgp, and BCRP expression by qRT-PCR and the relationship between doxorubicin uptake and ABC transporter expression via confocal microscopy in HT-29WT and HT-29 doxorubicin-resistant colon cancer cells (HT-29DxR). These cells were treated with doxorubicin and/or CoCl2 (chemical hypoxia), and reactive oxygen species inductors. We found that the combination of chemically induced hypoxia and doxorubicin promoted Pgp mRNA expression within 24 h in HT-29WT and HT-29DxR cells. Both doxorubicin and CoCl2 alone or in combination induced Pgp and BCRP expression, as demonstrated via confocal microscopy in each of the above two cell lines. Thus, we surmised that Pgp and BCRP expression may result from synergistic effects exerted by the combination of doxorubicin-induced ROS production and HIF-1α activity under hypoxic conditions. However, HIF-1α activity disruption via the administration of E3330, an APE-1 inhibitor, downregulated Pgp expression and increased doxorubicin delivery to HT-29 cells, where it served as a substrate for Pgp, indicating the existence of an indirect relationship between Pgp expression and doxorubicin accumulation. Thus, we concluded that Pgp and BCRP expression can be regulated via cross-talk between doxorubicin and hypoxia, promoting drug resistance in HT-29 WT, and HT-29DxR cells and that this process may be ROS dependent. J. Cell. Biochem. 118: 1868-1878, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  2. Structures of Reverse Transcriptase Pre- and Post-Excision Complexes Shed New Light on HIV-1 AZT Resistance

    Directory of Open Access Journals (Sweden)

    Walter A. Scott

    2011-01-01

    Full Text Available HIV-1 resistance to 3'-azido-2',3'-deoxythymidine (AZT, zidovudine results from mutations in reverse transcriptase that increase the ability of the enzyme to excise AZT-monophosphate after it has been incorporated. Crystal structures of complexes of wild type and mutant reverse transcriptase with double-stranded DNA with or without the excision product, AZT adenosine dinucleoside tetraphosphate (AZTppppA, have recently been reported [1]. The excision-enhancing mutations dramatically change the way the enzyme interacts with the excision product.

  3. Reversal of doxorubicin-induced vascular dysfunction by resveratrol in rat thoracic aorta: is there a possible role of nitric oxide synthase inhibition?/Sican torasik aortunda doksorubisinin olusturdugu fonksiyon bozuklugunun resveratrol uygulamasi ile duzelmesi: Nitrik oksit sentaz inhibisyonunun olasi rolu var mi?(Original Investigation/Ozgun Arastirma)

    National Research Council Canada - National Science Library

    Can, Cenk; Oral, Onur; Olukman, Murat; Erol, Ayse; Oktem, Gulperi; Cinar, Mehtap Gulcihan

    2009-01-01

    .... We investigated the impact of resveratrol on doxorubicin-induced vascular dysfunction in rat thoracic aorta with regard to NO synthesis in an experimental, prospective, controlled study. Methods...

  4. Time-programmable drug dosing allows the manipulation, suppression and reversal of antibiotic drug resistance in vitro

    Science.gov (United States)

    Yoshida, Mari; Reyes, Sabrina Galiñanes; Tsuda, Soichiro; Horinouchi, Takaaki; Furusawa, Chikara; Cronin, Leroy

    2017-06-01

    Multi-drug strategies have been attempted to prolong the efficacy of existing antibiotics, but with limited success. Here we show that the evolution of multi-drug-resistant Escherichia coli can be manipulated in vitro by administering pairs of antibiotics and switching between them in ON/OFF manner. Using a multiplexed cell culture system, we find that switching between certain combinations of antibiotics completely suppresses the development of resistance to one of the antibiotics. Using this data, we develop a simple deterministic model, which allows us to predict the fate of multi-drug evolution in this system. Furthermore, we are able to reverse established drug resistance based on the model prediction by modulating antibiotic selection stresses. Our results support the idea that the development of antibiotic resistance may be potentially controlled via continuous switching of drugs.

  5. Effect of Incremental Displacement on the Fracture Resistance Curve of Nuclear Piping Materials under Reverse Cyclic Loading

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang-Young [Kunsan National University, Gunsan (Korea, Republic of)

    2017-02-15

    Reverse cyclic loading introduces alternating tensile and compressive loads to a structure. Several researchers have reported that a reverse cyclic load decreases the fracture resistance curve of carbon steel. In this paper, the fracture toughness of SA312 TP304 stainless steel, which is a nuclear piping material, was investigated under a reverse cyclic load with various incremental plastic displacements. From the test results, the incremental plastic displacement effect on the fracture toughness curves was analyzed. The test results were also normalized and compared with SA516 Gr.70. It was found that the fracture toughness curves were degraded with small incremental displacement regardless of the kind of material. The normalized fracture toughness data showed that the small incremental plastic displacement induces a similar trend in lower fracture toughness in both materials. It seemed that the normalized fracture toughness curves are limited by the elongation of the materials.

  6. Reversal of c-MET-mediated Resistance to Cytotoxic Anticancer Drugs by a Novel c-MET Inhibitor TAS-115.

    Science.gov (United States)

    Kunii, Eiji; Ozasa, Hiroaki; Oguri, Tetsuya; Maeno, Ken; Fukuda, Satoshi; Uemura, Takehiro; Takakuwa, Osamu; Ohkubo, Hirotsugu; Takemura, Masaya; Niimi, Akio

    2015-10-01

    The cellular N-methyl-N'-nitroso-guanidine human osteosarcoma transforming gene (c-MET) protein is the receptor tyrosine kinase for hepatocyte growth factor. We recently found that c-MET protein expression and activation were enhanced in the majority of small cell lung cancer cell lines with cytotoxic anticancer drug resistance, and that down-regulation of c-MET reduced resistance to these drugs. Expression of c-MET was studied in three non-small cell lung cancer (NSCLC) cell lines, including six resistant cell strains to cytotoxic anticancer drugs. To assess the effect of c-MET activation on drug resistance, we studied drug sensitivity in the presence of a novel c-MET inhibitor TAS-115. c-MET expression and activation are also enhanced in some cytotoxic anticancer drug-resistant NSCLC cell lines, and inhibition of c-MET activation by TAS-115 reduced resistance of these cell lines to anticancer drugs. The mechanism of cellular resistance to anticancer drugs via hepatocyte growth factor/c-MET signal activation is not restricted to small cell lung cancer cell lines, and TAS-115 might be able to reverse the drug resistance of these cancer cells. Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  7. Panitumumab and pegylated liposomal doxorubicin to platinum-resistant epithelial ovarian cancer with KRAS wild-type: An ongoing, nonrandomized, multicenter, phase II trial

    DEFF Research Database (Denmark)

    Dahl Steffensen, Karina; Waldstrøm, Marianne; Lund, B

    2010-01-01

    , and head and neck cancer. No previous studies have evaluated the effect of panitumumab in OC based on KRAS mutation status. Methods: Eligibility criteria are confirmed stage I-IV primary epithelial ovarian/fallopian/peritoneal cancer patients with progression either during or within 6 months after end...... to a total of 33 patients. At present, 15 patients have been enrolled. The primary endpoint is to investigate the response rate in platinum-resistant, KRAS wild- type OC patients treated with PLD supplemented with panitumumab. Translational research is included as a secondary endpoint and tumor tissue...

  8. Graphene/phase change material nanocomposites: light-driven, reversible electrical resistivity regulation via form-stable phase transitions.

    Science.gov (United States)

    Wang, Yunming; Mi, Hongyi; Zheng, Qifeng; Ma, Zhenqiang; Gong, Shaoqin

    2015-02-04

    Innovative photoresponsive materials are needed to address the complexity of optical control systems. Here, we report a new type of photoresponsive nanomaterial composed of graphene and a form-stable phase change material (PCM) that exhibited a 3 orders of magnitude change in electrical resistivity upon light illumination while retaining its overall original solid form at the macroscopic level. This dramatic change in electrical resistivity also occurred reversibly through the on/off control of light illumination. This was attributed to the reversible phase transition (i.e., melting/recrystallization) behavior of the microscopic crystalline domains present in the form-stable PCM. The reversible phase transition observed in the graphene/PCM nanocomposite was induced by a reversible temperature change through the on/off control of light illumination because graphene can effectively absorb light energy and convert it to thermal energy. In addition, this graphene/PCM nanocomposite also possessed excellent mechanical properties. Such photoresponsive materials have many potential applications, including flexible electronics.

  9. Carbonyl Cyanide m-Chlorophenylhydrazine (CCCP) Reverses Resistance to Colistin, but Not to Carbapenems and Tigecycline in Multidrug-Resistant Enterobacteriaceae

    Science.gov (United States)

    Osei Sekyere, John; Amoako, Daniel G.

    2017-01-01

    Background: Carbapenems (CAR), colistin (CST), and tigecycline (TGC) alone or in combination therapy has become the last-resort antibiotics for treating infections caused by multidrug resistant (MDR) bacteria. However, resistance to these reserve antibiotics are increasingly being reported worldwide. Hence, the quest to find other agents that will synergistically restore the efficacy of these antibiotics have increased. Methods: Sixty-three clinical Enterobacteriaceae isolates comprising of Klebsiella pneumoniae (n = 24), Enterobacter spp. (n = 15), Serratia marcescens (n = 12), Citrobacter freundii (n = 8), Escherichia coli (n = 2), and K. oxytoca/michiganensis (n = 2) with known carbapenem resistance mechanisms and undescribed CST and TGC resistance mechanisms were subjected to broth microdilution and meropenem (MEM) disc synergy test in the presence and absence of carbonyl cyanide m-chlorophenylhydrazine (CCCP), a H+ conductor (protonophore). Results and conclusions: Susceptibility to MEM, imipenem (IMP), CST, and TGC was found in only 2, 0, 17, and 9 isolates respectively. Addition of CCCP reversed resistance to CST, TGC, IMP, and MEM in 44, 3, 0, and 0 isolates respectively; CST had the highest mean minimum inhibitory concentration (MIC) fold change (193.12; p MEM (1.70), IMP (1.49) and TGC (1.16). Eight isolates tested positive for the MEM-CCCP disc synergy test. We concluded that CCCP reverse CST resistance in CST-resistant Enterobacteriaceae. Although CCCP is an experimental agent with no therapeutic value clinically, further studies are necessary to decipher the mechanisms underlying the CST-CCCP synergy to inform the development of adjuvants that could be therapeutically effective in CST-resistant infections. PMID:28261184

  10. Evolved resistance to colistin and its loss due to genetic reversion in Pseudomonas aeruginosa

    OpenAIRE

    Ji-Young Lee; Young Kyoung Park; Eun Seon Chung; In Young Na; Kwan Soo Ko

    2016-01-01

    The increased reliance on colistin for treating multidrug-resistant Gram-negative bacterial infections has resulted in the emergence of colistin-resistant Pseudomonas aeruginosa. We attempted to identify genetic contributors to colistin resistance in vitro evolved isogenic colistin-resistant and -susceptible strains of two P. aeruginosa lineages (P5 and P155). Their evolutionary paths to acquisition and loss of colistin resistance were also tracked. Comparative genomic analysis revealed 13 an...

  11. Nondestructive evaluation for remanent life of aged 12Cr ferrite heat resisting steel by reversible permeability

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Kwon-Sang, E-mail: ryuks@kriss.re.kr [Korea Research Institute of Standards and Science, Centre for Materials Measurement, Doryong Dong, Yuseong-Gu, Daejeon 305-340 (Korea, Republic of); Kim, Chung-Seok [Automotive Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Baek, Un-bong [Korea Research Institute of Standards and Science, Centre for Materials Measurement, Doryong Dong, Yuseong-Gu, Daejeon 305-340 (Korea, Republic of); Lee, Jong Suk [Gangneung-Wonju National University, Wonju 220-711 (Korea, Republic of)

    2013-01-15

    We present a magnetic and nondestructive method to evaluate the remanent life of advanced ferritic steel using the value of reversible permeability. The method to measure reversible permeability is based on the theory that the value of reversible permeability is the same differential of the hysteresis loop. The measurement principle is based on the foundation of harmonics voltage induced in a sensing coil using a lock-in amplifier tuned to the frequency of the exciting one. Results obtained for reversible permeability, Vickers hardness, and tensile strength on the aged samples show that the peak interval of reversible permeability, Vickers hardness and tensile strength decrease as aging time increases. We could estimate the remanent life of advanced ferritic steel by using the relationship between the peak interval of reversible permeability and the Larson-Miller parameter, non-destructively. - Highlights: Black-Right-Pointing-Pointer Magnetic, nondestructive evaluation method of remanent life of 12Cr ferritic steel is presented. Black-Right-Pointing-Pointer Peak interval of reversible permeability decreases with the increase of aging time. Black-Right-Pointing-Pointer Mechanical properties decrease with the increase of aging time. Black-Right-Pointing-Pointer Magnetic and mechanical properties are decreased with increase of Larson-Miller parameter. Black-Right-Pointing-Pointer Reversible permeability is nondestructively used to estimate remanent life of 12Cr ferrite steel.

  12. Efficacy of the chemotherapeutic action of HPMA copolymer‐bound doxorubicin in a solid tumor model of ovarian carcinoma

    National Research Council Canada - National Science Library

    Minko, Tamara; Kopečková, Pavla; Kopeček, Jindřich

    2000-01-01

    Anticancer activity and main mechanisms of action of free doxorubicin (DOX) and HPMA copolymer‐bound DOX (P(GFLG)‐DOX) were studied in solid tumor mice models of DOX sensitive and resistant human ovarian carcinoma...

  13. Computational Analysis of Molecular Interaction Networks Underlying Change of HIV-1 Resistance to Selected Reverse Transcriptase Inhibitors.

    Science.gov (United States)

    Kierczak, Marcin; Dramiński, Michał; Koronacki, Jacek; Komorowski, Jan

    2010-12-12

    Despite more than two decades of research, HIV resistance to drugs remains a serious obstacle in developing efficient AIDS treatments. Several computational methods have been developed to predict resistance level from the sequence of viral proteins such as reverse transcriptase (RT) or protease. These methods, while powerful and accurate, give very little insight into the molecular interactions that underly acquisition of drug resistance/hypersusceptibility. Here, we attempt at filling this gap by using our Monte Carlo feature selection and interdependency discovery method (MCFS-ID) to elucidate molecular interaction networks that characterize viral strains with altered drug resistance levels. We analyzed a number of HIV-1 RT sequences annotated with drug resistance level using the MCFS-ID method. This let us expound interdependency networks that characterize change of drug resistance to six selected RT inhibitors: Abacavir, Lamivudine, Stavudine, Zidovudine, Tenofovir and Nevirapine. The networks consider interdependencies at the level of physicochemical properties of mutating amino acids, eg,: polarity. We mapped each network on the 3D structure of RT in attempt to understand the molecular meaning of interacting pairs. The discovered interactions describe several known drug resistance mechanisms and, importantly, some previously unidentified ones. Our approach can be easily applied to a whole range of problems from the domain of protein engineering. A portable Java implementation of our MCFS-ID method is freely available for academic users and can be obtained at: http://www.ipipan.eu/staff/m.draminski/software.htm.

  14. Prospective randomized trial of docetaxel versus doxorubicin in patients with metastatic breast cancer.

    Science.gov (United States)

    Chan, S; Friedrichs, K; Noel, D; Pintér, T; Van Belle, S; Vorobiof, D; Duarte, R; Gil Gil, M; Bodrogi, I; Murray, E; Yelle, L; von Minckwitz, G; Korec, S; Simmonds, P; Buzzi, F; González Mancha, R; Richardson, G; Walpole, E; Ronzoni, M; Murawsky, M; Alakl, M; Riva, A; Crown, J

    1999-08-01

    This phase III study compared docetaxel and doxorubicin in patients with metastatic breast cancer who had received previous alkylating agent-containing chemotherapy. Patients were randomized to receive an intravenous infusion of docetaxel 100 mg/m(2) or doxorubicin 75 mg/m(2) every 3 weeks for a maximum of seven treatment cycles. A total of 326 patients were randomized, 165 to receive doxorubicin and 161 to receive docetaxel. Overall, docetaxel produced a significantly higher rate of objective response than did doxorubicin (47.8% v 33.3%; P =.008). Docetaxel was also significantly more active than doxorubicin in patients with negative prognostic factors, such as visceral metastases (objective response, 46% v 29%) and resistance to prior chemotherapy (47% v 25%). Median time to progression was longer in the docetaxel group (26 weeks v 21 weeks; difference not significant). Median overall survival was similar in the two groups (docetaxel, 15 months; doxorubicin, 14 months). There was one death due to infection in each group, and an additional four deaths due to cardiotoxicity in the doxorubicin group. Although neutropenia was similar in both groups, febrile neutropenia and severe infection occurred more frequently in the doxorubicin group. For severe nonhematologic toxicity, the incidences of cardiac toxicity, nausea, vomiting, and stomatitis were higher among patients receiving doxorubicin, whereas diarrhea, neuropathy, fluid retention, and skin and nail changes were higher among patients receiving docetaxel. The observed differences in activity and toxicity profiles provide a basis for therapy choice and confirms the rationale for combination studies in early breast cancer.

  15. Lersivirine, a Nonnucleoside Reverse Transcriptase Inhibitor with Activity against Drug-Resistant Human Immunodeficiency Virus Type 1▿ ‡

    Science.gov (United States)

    Corbau, Romuald; Mori, Julie; Phillips, Chris; Fishburn, Lesley; Martin, Alex; Mowbray, Charles; Panton, Wendy; Smith-Burchnell, Caroline; Thornberry, Adele; Ringrose, Heather; Knöchel, Thorsten; Irving, Steve; Westby, Mike; Wood, Anthony; Perros, Manos

    2010-01-01

    The nonnucleoside reverse transcriptase inhibitors (NNRTIs) are key components of highly active antiretroviral therapy (HAART) for the treatment of human immunodeficiency virus type 1 (HIV-1). A major problem with the first approved NNRTIs was the emergence of mutations in the HIV-1 reverse transcriptase (RT), in particular K103N and Y181C, which led to resistance to the entire class. We adopted an iterative strategy to synthesize and test small molecule inhibitors from a chemical series of pyrazoles against wild-type (wt) RT and the most prevalent NNRTI-resistant mutants. The emerging candidate, lersivirine (UK-453,061), binds the RT enzyme in a novel way (resulting in a unique resistance profile), inhibits over 60% of viruses bearing key RT mutations, with 50% effective concentrations (EC50s) within 10-fold of those for wt viruses, and has excellent selectivity against a range of human targets. Altogether lersivirine is a highly potent and selective NNRTI, with excellent efficacy against NNRTI-resistant viruses. PMID:20660667

  16. Lersivirine, a nonnucleoside reverse transcriptase inhibitor with activity against drug-resistant human immunodeficiency virus type 1.

    Science.gov (United States)

    Corbau, Romuald; Mori, Julie; Phillips, Chris; Fishburn, Lesley; Martin, Alex; Mowbray, Charles; Panton, Wendy; Smith-Burchnell, Caroline; Thornberry, Adele; Ringrose, Heather; Knöchel, Thorsten; Irving, Steve; Westby, Mike; Wood, Anthony; Perros, Manos

    2010-10-01

    The nonnucleoside reverse transcriptase inhibitors (NNRTIs) are key components of highly active antiretroviral therapy (HAART) for the treatment of human immunodeficiency virus type 1 (HIV-1). A major problem with the first approved NNRTIs was the emergence of mutations in the HIV-1 reverse transcriptase (RT), in particular K103N and Y181C, which led to resistance to the entire class. We adopted an iterative strategy to synthesize and test small molecule inhibitors from a chemical series of pyrazoles against wild-type (wt) RT and the most prevalent NNRTI-resistant mutants. The emerging candidate, lersivirine (UK-453,061), binds the RT enzyme in a novel way (resulting in a unique resistance profile), inhibits over 60% of viruses bearing key RT mutations, with 50% effective concentrations (EC(50)s) within 10-fold of those for wt viruses, and has excellent selectivity against a range of human targets. Altogether lersivirine is a highly potent and selective NNRTI, with excellent efficacy against NNRTI-resistant viruses.

  17. Reversion of Hormone Treatment Resistance with the Addition of an mTOR Inhibitor in Endometrial Stromal Sarcoma

    Directory of Open Access Journals (Sweden)

    J. Martin-Liberal

    2014-01-01

    Full Text Available Background. Endometrial stromal sarcomas (ESS are a subtype of gynaecological sarcomas characterized by the overexpression of hormone receptors. Hormone treatment is widely used in ESS but primary or acquired resistance is common. The mammalian target of rapamycin (mTOR pathway has been suggested to play a key role in the mechanisms of hormone resistance. Recent studies in breast and prostate cancer demonstrate that this resistance can be reversed with the addition of an mTOR inhibitor. This phenomenon has never been reported in ESS. Methods. We report the outcome of one patient with pretreated, progressing low grade metastatic ESS treated with medroxyprogesterone acetate in combination with the mTOR inhibitor sirolimus. Results. Partial response was achieved following the addition of sirolimus to the hormone treatment. Response has been maintained for more than 2 years with minimal toxicity and treatment is ongoing. Conclusion. This case suggests that the resistance to the hormone manipulation in ESS can be reversed by the addition of an mTOR pathway inhibitor. This observation is highly encouraging and deserves further investigation.

  18. PKCα Attenuates Jagged-1-mediated Notch Signaling in ErbB-2 positive Breast Cancer to Reverse Trastuzumab Resistance

    Science.gov (United States)

    Pandya, Kinnari; Wyatt, Debra; Gallagher, Brian; Shah, Deep; Baker, Andrew; Bloodworth, Jeffrey; Zlobin, Andrei; Pannuti, Antonio; Green, Andrew; Ellis, Ian O.; Filipovic, Aleksandra; Sagert, Jason; Rana, Ajay; Albain, Kathy S.; Miele, Lucio; Denning, Mitchell F.; Osipo, Clodia

    2015-01-01

    Purpose Breast cancer is the second leading cause of cancer mortality among women worldwide. The major problem with current treatments is tumor resistance, recurrence, and disease progression. ErbB-2 positive breast tumors are aggressive and frequently become resistant to trastuzumab or lapatinib. We showed previously that Notch-1 is required for trastuzumab resistance in ErbB-2 positive breast cancer. Experimental Design Here, we sought to elucidate mechanisms by which ErbB-2 attenuates Notch signaling and how this is reversed by trastuzumab or lapatinib. Results The current study elucidates a novel Notch inhibitory mechanism by which PKCα downstream of ErbB-2: 1. Restricts the availability of Jagged-1 at the cell surface to trans activate Notch; 2. Restricts the critical interaction between Jagged-1 and Mindbomb-1, an E3 ligase that is required for Jagged-1 ubiquitinylation and subsequent Notch activation; 3. Reverses trastuzumab resistance in vivo; and 4. Predicts better outcome in women with ErbB-2 positive breast cancer. Conclusions The clinical impact of these studies is PKCα is potentially a good prognostic marker for low Notch activity and increased trastuzumab sensitivity in ErbB-2 positive breast cancer. Moreover, women with ErbB-2 positive breast tumors expressing high Notch activation and low PKCα expression could be the best candidates for anti-Notch therapy. PMID:26350262

  19. Preparation, characterisation and maintenance of drug efficacy of doxorubicin-loaded human serum albumin (HSA) nanoparticles.

    Science.gov (United States)

    Dreis, S; Rothweiler, F; Michaelis, M; Cinatl, J; Kreuter, J; Langer, K

    2007-08-16

    Human serum albumin (HSA) nanoparticles represent promising drug carrier systems. Binding of cytostatics to HSA nanoparticles may diminish their toxicity, optimise their body distribution and/or may overcome multidrug resistance. In the present study, doxorubicin-loaded HSA nanoparticle preparations were prepared. Doxorubicin was loaded to the HSA nanoparticles either by adsorption to the nanoparticles' surfaces or by incorporation into the particle matrix. Both loading strategies resulted in HSA nanoparticles of a size range between 150nm and 500nm with a loading efficiency of 70-95%. The influence on cell viability of the resulting nanoparticles was investigated in two different neuroblastoma cell lines. The anti-cancer effects of the drug-loaded nanoparticles were increased in comparison to doxorubicin solution. Based on these result a standard protocol for the preparation of doxorubicin-loaded HSA nanoparticles for further antitumoural studies was established.

  20. Pegylated liposomal doxorubicin: optimizing the dosing schedule in ovarian cancer.

    Science.gov (United States)

    Rose, Peter G

    2005-03-01

    The need for effective, well-tolerated, and convenient therapies for patients with advanced ovarian cancer has led researchers to continually refine chemotherapeutic regimens to balance efficacy with safety and tolerability in order to maintain or improve patient quality of life. In this article, we review current strategies for the optimal dosing of pegylated liposomal doxorubicin (DOXIL; Tibotec Therapeutics, a division of Ortho Biotech Products, L.P., Bridgewater, NJ, http://www.tibotec.com; Caelyx, Schering-Plough Corporation, Kenilworth, NJ, http://www.sch-plough.com) in relapsed ovarian cancer. Pegylated liposomal doxorubicin has demonstrated efficacy in the treatment of recurrent/resistant ovarian cancer in several clinical trials utilizing a dose of 50 mg/m2 every 4 weeks. The most common adverse events associated with pegylated liposomal doxorubicin treatment in these studies-hand-foot syndrome (HFS, also known as palmar-plantar erythrodysesthesia) and stomatitis-are schedule and dose dependent, respectively, and do not typically lead to discontinuation of therapy. Several phase II and retrospective studies support the use of pegylated liposomal doxorubicin 40 mg/m2 every 4 weeks (dose intensity of 10 mg/m2 weekly) to optimize clinical efficacy and minimize the occurrence of schedule- and dose-related adverse events in patients with recurrent/relapsed ovarian cancer. Further reductions in dose intensity are necessary for use in combined chemotherapy regimens. Antitumor activity was maintained, with reduced incidences of HFS and stomatitis. Given the chronic course of ovarian cancer, the improved tolerability profile of pegylated liposomal doxorubicin 40 mg/m2 combined with a convenient once-monthly dosing schedule may translate into an improved quality of life for patients with ovarian cancer.

  1. Efficient reverse transcription using locked nucleic acid nucleotides towards the evolution of nuclease resistant RNA aptamers

    DEFF Research Database (Denmark)

    Crouzier, Lucile; Dubois, Camille; Edwards, Stacey L

    2012-01-01

    We found that SuperScript® III Reverse Transcriptase is an efficient enzyme for the recognition of LNA nucleotides, making it a prime candidate to be used in de novo selection of LNA containing RNA aptamers.......We found that SuperScript® III Reverse Transcriptase is an efficient enzyme for the recognition of LNA nucleotides, making it a prime candidate to be used in de novo selection of LNA containing RNA aptamers....

  2. The study of resistant mechanisms and reversal in an imatinib resistant Ph+ acute lymphoblastic leukemia cell line.

    Science.gov (United States)

    Xing, Hongyun; Yang, Xi; Liu, Ting; Lin, Juan; Chen, Xiaoyi; Gong, Yuping

    2012-04-01

    In this study, we established an imatinib resistant Ph+ acute lymphoblastic leukemia (ALL) cell line SUP-B15/RI in vitro and studied the mechanism of imatinib resistance. Our results showed that the BCR-ABL1 fusion gene and the mdr1 gene were 6.1 times and 1.7 times, respectively, as high as that of parental SUP-B15 cell line. We found no mutation in the Abl kinase domain of SUP-B15/RI. Furthermore, the detection of cell signaling pathway of PI3K/AKT/mTOR, RAS/RAF, NF-κB, JNK and STAT showed the up-regulation of phosphorylation of AKT, mTOR, P70S6K, and RAF, ERK, and MEK, down-regulation of PTEN and 4EBP-1, and no change in other cell signaling pathways in SUP-B15/RI. However, dasatinib and nilotinib showed partial resistance. Interestingly, bortezomib had no resistance. Imatinib combination with rapamycin had synergistic effect on overcoming the resistance. Altogether, over-expression of BCR-ABL1 and mdr1 gene were involved in the resistance mechanisms, and up-regulation of the cell signaling pathways of PI3K/AKT/mTOR, RAS/RAF in SUP-B15/RI cell line may be correlated with them. The SUP-B15/RI cell line was also resistant to the second generation tyrosine kinase, dasatinib, and nilotinib, not bortezomib. The combination of imatinib with rapamycin can partially overcome the resistance and blockade of the ubiquitin-proteasome can be also a promising pathway to overcome imatinib resistance. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Inhibition of long non-coding RNA ROR reverses resistance to Tamoxifen by inducing autophagy in breast cancer.

    Science.gov (United States)

    Li, Yuehua; Jiang, Baohong; Zhu, Hongbo; Qu, Xiaofei; Zhao, Liqin; Tan, Yeru; Jiang, Yiling; Liao, Mingchu; Wu, Xiaoping

    2017-06-01

    This study explored the mechanism underlying long non-coding RNA ROR regulating autophagy on Tamoxifen resistance in breast cancer. Cancer tissues and adjacent normal tissues were collected from 74 breast cancer patients. Human breast cancer BT474 cells were assigned into blank, phosphate buffered saline, Tamoxifen, negative control + Tamoxifen, siROR + Tamoxifen, 3-methyladenine + Tamoxifen, and siROR + 3-methyladenine + TA groups. The expression of long non-coding RNA ROR and expressions of multi-drug resistance-associated P-glycoprotein and glutathione S-transferase-π messenger RNA were detected using quantitative real-time polymerase chain reaction. The expressions of light chain 3, Beclin 1, multi-drug resistance-associated P-glycoprotein, and glutathione S-transferase-π protein were determined using western blotting. Cell proliferation, invasion, and migration abilities were measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, Transwell assay, and scratch test, respectively. The long non-coding RNA ROR expression was higher in the breast cancer tissues than that in the adjacent normal tissues. Compared with the blank group, light chain 3 and Beclin 1 expressions were increased in the siROR + Tamoxifen group but decreased in the 3-methyladenine + Tamoxifen group; these data indicated that downregulated long non-coding RNA ROR promoted autophagy. In comparison with the blank group, multi-drug resistance-associated P-glycoprotein and glutathione S-transferase-π messenger RNA and protein expressions were reduced in the siROR + Tamoxifen group but elevated in the 3-methyladenine + Tamoxifen group, suggesting that downregulated long non-coding RNA ROR suppressed the drug resistance to Tamoxifen and the inhibition of autophagy reversed the effect of long non-coding RNA ROR on drug resistance. Compared with the Tamoxifen, negative control, and siROR + 3-methyladenine + Tamoxifen groups, the cell

  4. Evodiamine synergizes with doxorubicin in the treatment of chemoresistant human breast cancer without inhibiting P-glycoprotein.

    Directory of Open Access Journals (Sweden)

    Shengpeng Wang

    Full Text Available Drug resistance is one of the main hurdles for the successful treatment of breast cancer. The synchronous targeting of apoptosis resistance and survival signal transduction pathways may be a promising approach to overcome drug resistance. In this study, we determined that evodiamine (EVO, a major constituent of the Chinese herbal medicine Evodiae Fructus, could induce apoptosis of doxorubicin (DOX-sensitive MCF-7 and DOX-resistant MCF-7/ADR cells in a caspase-dependent manner, as confirmed by significant increases of cleaved poly(ADP-ribose polymerase (PARP, caspase-7/9, and caspase activities. Notably, the reversed phenomenon of apoptosis resistance by EVO might be attributed to its ability to inhibit the Ras/MEK/ERK pathway and the expression of inhibitors of apoptosis (IAPs. Furthermore, our results indicated that EVO enhanced the apoptotic action of DOX by inhibiting the Ras/MEK/ERK cascade and the expression of IAPs without inhibiting the expression and activity of P-glycoprotein (P-gp. Taken together, our data indicate that EVO, a natural product, may be useful applied alone or in combination with DOX for the treatment of resistant breast cancer.

  5. Design, synthesis and evaluation of novel triazole core based P-glycoprotein-mediated multidrug resistance reversal agents.

    Science.gov (United States)

    Jiao, Lei; Qiu, Qianqian; Liu, Baomin; Zhao, Tianxiao; Huang, Wenlong; Qian, Hai

    2014-12-15

    A novel series of triazol-N-ethyl-tetrahydroisoquinoline based compounds were designed and synthesized via click chemistry. Most of the synthesized compounds showed P-glycoprotein (P-gp)-mediated multidrug resistance (MDR) reversal activities. Among them, compound 7 with little cytotoxicity towards GES-1 cells (IC50 >80μM) and K562/A02 cells (IC50 >80μM) exhibited more potency than verapamil (VRP) on increasing anticancer drug accumulation in K562/A02 cells. Moreover, compound 7 could significantly reverse MDR in a dose-dependent manner and also persist longer chemo-sensitizing effect than VRP with reversibility. Further mechanism studies revealed that compound 7 in reversing MDR revealed that it could remarkably increase the intracellular accumulation of both rhodamine-123 (Rh123) and adriamycin (ADM) in K562/A02 cells as well as inhibit their efflux from the cells. These results suggested that compound 7 showed more potency than the classical P-gp inhibitor VRP under the same conditions, which may be a promising P-gp-mediated MDR modulator for further development. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. The role of Nardostachys jatamansi against doxorubicin-induced ...

    African Journals Online (AJOL)

    SUBASHINI

    2013-12-04

    Dec 4, 2013 ... cytokine, protects against doxorubicin-induced oxidative organ injury. Key words: Nardostachys jatamansi, doxorubicin, cytokine, glutathione, malondialdehyde, myeloperoxidase. INTRODUCTION. Doxorubicin (DOX) is a quinine-containing anticancer antibiotic and widely used to treat different types of.

  7. Identification of a Novel Scaffold for Allosteric Inhibition of Wild Type and Drug Resistant HIV-1 Reverse Transcriptase by Fragment Library Screening

    NARCIS (Netherlands)

    Geitmann, M.; Elinder, M; Seeger, C; Brandt, P; de Esch, I.J.P.; Danielson, U.H.

    2011-01-01

    A novel scaffold inhibiting wild type and drug resistant variants of human immunodeficiency virus type 1 reverse transcriptase (HIV-1RT) has been identified in a library consisting of 1040 fragments. The fragments were significantly different from already known non-nucleoside reverse transcriptase

  8. Baseline resistance to nucleoside reverse transcriptase inhibitors fails to predict virologic response to combination therapy in children (PACTG 338

    Directory of Open Access Journals (Sweden)

    McIntosh Kenneth

    2007-02-01

    Full Text Available Abstract Background The association between baseline drug resistance mutations and subsequent increase in viral failure has not been established for HIV-infected children. We evaluated drug resistance mutations at 39 codon sites (21 protease inhibitor (PI resistant codons and 18 nucleoside reverse transcriptase inhibitor (NRTI resistant codons for 92 clinically stable NRTI-experienced, PI-naive HIV-infected children 2 to 17 years of age who were initiating new therapy with ritonavir plus zidovudine (ZDV and lamivudine or plus stavudine. The association between baseline drug resistance mutations and subsequent viral failure after 12 and 24 weeks of highly active antiretroviral therapy (HAART was studied. Results There were few primary PI associated mutations in this PI-naïve population, but 84% had NRTI mutations – codons 215 (66%, 41 (42%, 67 (37%, 210 (33% and 70 (32%. None of the specific baseline drug resistance mutations were associated with a higher rate of virologic failure after 12 or 24 weeks of HAART. Median week 12 viral load decreased as the total number of NRTI mutations at baseline increased (P = 0.006. Specifically, a higher level of baseline ZDV resistance mutation was associated with a decrease in viral failure after 12 weeks on a ZDV-containing HAART regimen (P = 0.017. Conclusion No increase was seen in the rate of viral failure after HAART associated with the presence of resistance mutations at baseline. This paradoxical result may be due to adherence, replicative capacity, or ZDV hypersusceptibility to the new regimen.

  9. Distinctive Drug-resistant Mutation Profiles and Interpretations of HIV-1 Proviral DNA Revealed by Deep Sequencing in Reverse Transcriptase.

    Science.gov (United States)

    Yin, Qian Qian; Li, Zhen Peng; Zhao, Hai; Pan, Dong; Wang, Yan; Xu, Wei Si; Xing, Hui; Feng, Yi; Jiang, Shi Bo; Shao, Yi Ming; Ma, Li Ying

    2016-04-01

    To investigate distinctive features in drug-resistant mutations (DRMs) and interpretations for reverse transcriptase inhibitors (RTIs) between proviral DNA and paired viral RNA in HIV-1-infected patients. Forty-three HIV-1-infected individuals receiving first-line antiretroviral therapy were recruited to participate in a multicenter AIDS Cohort Study in Anhui and Henan Provinces in China in 2004. Drug resistance genotyping was performed by bulk sequencing and deep sequencing on the plasma and whole blood of 77 samples, respectively. Drug-resistance interpretation was compared between viral RNA and paired proviral DNA. Compared with bulk sequencing, deep sequencing could detect more DRMs and samples with DRMs in both viral RNA and proviral DNA. The mutations M184I and M230I were more prevalent in proviral DNA than in viral RNA (Fisher's exact test, PDNA, and 5 of these samples with different DRMs between proviral DNA and paired viral RNA showed a higher level of drug resistance to the first-line drugs. Considering 'minority resistant variants', 22 samples (28.57%) were associated with a higher level of drug resistance to the tested RTIs for proviral DNA when compared with paired viral RNA. Compared with viral RNA, the distinctive information of DRMs and drug resistance interpretations for proviral DNA could be obtained by deep sequencing, which could provide more detailed and precise information for drug resistance monitoring and the rational design of optimal antiretroviral therapy regimens. Copyright © 2016 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

  10. Synthetic paclitaxel-octreotide conjugate reversing the resistance of A2780/Taxol to paclitaxel in xenografted tumor in nude mice.

    Science.gov (United States)

    Chen, Xi; Zhang, Xiao-Yu; Shen, Yang; Fan, Li-Li; Ren, Mu-Lan; Wu, Yong-Ping

    2016-12-13

    Peptide hormone-based targeted therapy to tumors has been studied extensively. Our previous study shows that somatostatin receptor expresses high level on drug-resistant human ovarian cancer. The paclitaxel-octreotide conjugate (POC) exhibits enhanced growth inhibition, as well as reduced toxicity, in paclitaxel-resistant human ovarian cancer cells. The aim of this study was to investigate the effect of targeted cytotoxicity and potential reversal mechanism of resistance in paclitaxel-resistant human ovarian cancer cells xenografted into nude mice. The SSTR2 shows higher expression levels in tumor tissue. Moreover, fluorescein-labeled POC displays favorable targeting in tumor cells. POC presents the perfect efficacy in inhibiting tumor growth and exerts lower or no toxic effects on normal tissues. Real-time PCR and Western Blotting has demonstrated that the mRNA and protein expressions of SSTR2 in POC group were significantly higher, while MDR1, α-tubulin, βIII-tubulin, VEGF and MMP-9 were significantly lower than in the other treatment groups and controls. Combined with the previous study in vitro, this study evaluates an effective approach on the treatment of paclitaxel-resistant ovarian cancer which expresses somatostatin receptor SSTR. Our investigation has also revealed the possible molecular mechanism of POC in treating the ovarian cancer, and therefore, provided a theoretical basis for the clinical application of this newly-invented compound.

  11. Improving fold resistance prediction of HIV-1 against protease and reverse transcriptase inhibitors using artificial neural networks.

    Science.gov (United States)

    Sheik Amamuddy, Olivier; Bishop, Nigel T; Tastan Bishop, Özlem

    2017-08-15

    Drug resistance in HIV treatment is still a worldwide problem. Predicting resistance to antiretrovirals (ARVs) before starting any treatment is important. Prediction accuracy is essential, as low-accuracy predictions increase the risk of prescribing sub-optimal drug regimens leading to patients developing resistance sooner. Artificial Neural Networks (ANNs) are a powerful tool that would be able to assist in drug resistance prediction. In this study, we constrained the dataset to subtype B, sacrificing generalizability for a higher predictive performance, and demonstrated that the predictive quality of the ANN regression models have definite improvement for most ARVs. Trained regression ANNs were optimized for eight protease inhibitors, six nucleoside reverse transcriptase (RT) inhibitors and four non-nucleoside RT inhibitors by experimenting combinations of rare variant filtering (none versus 1 residue occurrence) and ANN topologies (1-3 hidden layers with 2, 4, 6, 8 and 10 nodes per layer). Single hidden layers (5-20 nodes) were used for training where overfitting was detected. 5-fold cross-validation produced mean R2 values over 0.95 and standard deviations lower than 0.04 for all but two antiretrovirals. Overall, higher accuracies and lower variances (compared to results published in 2016) were obtained by experimenting with various preprocessing methods, while focusing on the most prevalent subtype in the raw dataset (subtype B).We thus highlight the need to develop and make available subtype-specific datasets for developing higher accuracy in drug-resistance prediction methods.

  12. Deficiency in p53 is required for doxorubicin induced transcriptional activation of NF-small ka, CyrillicB target genes in human breast cancer

    NARCIS (Netherlands)

    Dalmases, A.; Gonzalez, I.; Menendez, S.; Arpi, O.; Corominas, J.; Servitja, S.; Tusquets, I.; Chamizo, C.; Rincon, R.; Espinosa, L.; Bigas, A.; Eroles, P.; Furriol, J.; Lluch, A.; Rovira, A.; Albanell, J.; Rojo, F.

    2014-01-01

    NF-small ka, CyrillicB has been linked to doxorubicin resistance in breast cancer patients. NF-small ka, CyrillicB nuclear translocation and DNA binding in doxorubicin treated-breast cancer cells have been extensively examined; however its functional relevance at transcriptional level on NF-small

  13. JS-K, a GST-activated nitric oxide donor prodrug, enhances chemo-sensitivity in renal carcinoma cells and prevents cardiac myocytes toxicity induced by Doxorubicin.

    Science.gov (United States)

    Qiu, Mingning; Ke, Longzhi; Zhang, Sai; Zeng, Xin; Fang, Zesong; Liu, Jianjun

    2017-08-01

    Doxorubicin, a highly effective and widely used anthracycline antibiotic in multiple chemotherapy regimens, has been limited by its cardiotoxicity. The aim of this study is to investigate the effect of nitric oxide donor prodrug JS-K on proliferation and apoptosis in renal carcinoma cells and cardiac myocytes toxicity induced by Doxorubicin and to explore possible p53-related mechanism in renal carcinoma cells. The effect of JS-K on anti-cancer activity of Doxorubicin was investigated in renal carcinoma cells via detecting cell proliferation, cytotoxicity, cell death and apoptosis and expressions of apoptotic-related proteins. Effect of p53 on the combination of JS-K and Doxorubicin was determined using p53 inhibitor Pifithrin-α and p53 activator III. Furthermore, the effect of JS-K on cardiac myocytes toxicity of Doxorubicin was investigated in H9c2 (2-1) cardiac myocytes via measuring cell growth, cell death and apoptosis, expressions of proteins involved in apoptosis and intracellular reactive oxygen species. We demonstrated that JS-K could increase Doxorubicin-induced renal carcinoma cell growth suppression and apoptosis and could increase expressions of proteins that are involved in apoptosis. Additionally, Pifithrin-α reversed the promoting effect of JS-K on Doxorubicin-induced renal carcinoma cell apoptosis; conversely, the p53 activator III exacerbated the promoting effect of JS-K on Doxorubicin-induced renal carcinoma cell apoptosis. Furthermore, JS-K protected H9c2 (2-1) cardiac myocytes against Doxorubicin-induced toxicity and decreased Doxorubicin-induced reactive oxygen species production. JS-K enhances the anti-cancer activity of Doxorubicin in renal carcinoma cells by upregulating p53 expression and prevents cardiac myocytes toxicity of Doxorubicin by decreasing oxidative stress.

  14. Design, Synthesis, and Biological Evaluation of Novel Cholesteryl Peptides with Anticancer and Multidrug Resistance-Reversing Activities.

    Science.gov (United States)

    Deng, Xin; Qiu, Qianqian; Wang, Xuekun; Huang, Wenlong; Qian, Hai

    2016-03-01

    Antimicrobial peptides have been suggested as promising chemotherapeutics for cancer therapy due to their efficient antitumor activity and lower toxicity to benign cells. In previous study, we find the peptide B1 presents specific cytotoxicity to cancer cells. As hydrophobicity plays a pivotal role in the anticancer activity of peptide, we introduce cholesterol-like moiety (3β-amino-5-cholestene) to the N-terminus of B1 expect to ameliorate the anticancer activity of B1. Biological evaluations revealed that target peptides show improved anticancer activity. The peptides can also penetrate into the cytoplasm and activating mitochondria-cytochrome c apoptosis pathway. Besides, the peptides acted on multidrug-resistant cells and had multidrug resistance-reversing activity. It is therefore suggested these peptides might be promising candidates for oncotherapy. © 2015 John Wiley & Sons A/S.

  15. Global DNA hypermethylation-associated cancer chemotherapy resistance and its reversion with the demethylating agent hydralazine

    Directory of Open Access Journals (Sweden)

    Benitez-Bribiesca Luis

    2006-08-01

    Full Text Available Abstract Background The development of resistance to cytotoxic chemotherapy continues to be a major obstacle for successful anticancer therapy. It has been shown that cells exposed to toxic concentrations of commonly used cancer chemotherapy agents develop DNA hypermetylation. Hence, demethylating agents could play a role in overcoming drug resistance. Methods MCF-7 cells were rendered adriamycin-resistant by weekly treatment with adriamycin. Wild-type and the resulting MCF-7/Adr cells were analyzed for global DNA methylation. DNA methyltransferase activity and DNA methyltransferase (dnmt gene expression were also determined. MCF-7/Adr cells were then subjected to antisense targeting of dnmt1, -3a, and -b genes and to treatment with the DNA methylation inhibitor hydralazine to investigate whether DNA demethylation restores sensitivity to adriamycin. Results MCF-7/Adr cells exhibited the multi-drug resistant phenotype as demonstrated by adriamycin resistance, mdr1 gene over-expression, decreased intracellular accumulation of adriamycin, and cross-resistance to paclitaxel. The mdr phenotype was accompanied by global DNA hypermetylation, over-expression of dnmt genes, and increased DNA methyltransferase activity as compared with wild-type MCF-7 cells. DNA demethylation through antisense targeting of dnmts or hydralazine restored adriamycin sensitivity of MCF-7/Adr cells to a greater extent than verapamil, a known inhibitor of mdr protein, suggesting that DNA demethylation interferes with the epigenetic reprogramming that participates in the drug-resistant phenotype. Conclusion We provide evidence that DNA hypermethylation is at least partly responsible for development of the multidrug-resistant phenotype in the MCF-7/Adr model and that hydralazine, a known DNA demethylating agent, can revert the resistant phenotype.

  16. Feedback control of resistive wall modes in the reversed field pinch

    OpenAIRE

    Yadikin, Dimitry

    2004-01-01

    A wide range of unstable current driven MHD modes is present in the re- versed τeld pinch (RFP) conτguration. An ideally conducting wall facing the plasma can stabilize the ideal MHD modes. In the presence of a resistive wall characterized by the wall time τw, fast mode rotation with the frequency exceeding the inverse wall time gives stabilization for resistive MHD modes. The ideal MHD modes in the RFP are non-rotating modes and can not be stabilized by the resistive wall. Instead they are c...

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

    Directory of Open Access Journals (Sweden)

    Jianfang Chen

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

  18. Secondary metabolites inhibiting ABC transporters and reversing resistance of cancer cells and fungi to cytotoxic and antimicrobial agents

    Directory of Open Access Journals (Sweden)

    Michael eWink

    2012-04-01

    Full Text Available Fungal, bacterial and cancer cells can develop resistance against antifungal, antibacterial or anticancer agents. Mechanisms of resistance are complex and often multifactorial. Mechanisms include: 1. Activation of ABC transporters, such as P-gp, which pump out lipophilic compounds that have entered a cell, 2. Activation of cytochrome p450 oxidases which can oxidise lipophilic agents to make them more hydrophilic and accessible for conjugation reaction with glucuronic acid, sulphate or amino acids, and 3. Activation of glutathione transferase, which can conjugate xenobiotics. This review summarises the evidence that secondary metabolites of plants, such as alkaloids, phenolics and terpenoids can interfere with ABC transporters in cancer cells, parasites, bacteria and fungi. Among the active natural products several lipophilic terpenoids ( monoterpenes, diterpenes, triterpenes (including saponins, steroids (including cardiac glycosides and tetraterpenes but also some alkaloids (isoquinoline, protoberberine, quinoline, indole, monoterpene indole, and steroidal alkaloids function probably as competitive inhibitors of P-gp, MRP1 and BCRP in cancer cells, or efflux pumps in bacteria (NorA and fungi. More polar phenolics (phenolic acids, flavonoids, catechins, chalcones, xanthones, stilbenes, anthocyanins, tannins, anthraquinones, and naphthoquinones directly inhibit proteins forming several hydrogen and ionic bonds and thus disturbing the 3D structure of the transporters. The natural products may be interesting in medicine or agriculture as they can enhance the activity of active chemotherapeutics or pesticides or even reverse MDR, at least partially, of adapted and resistant cells. If these secondary metabolites are applied in combination with a cytotoxic or antimicrobial agent, they may reverse resistance in a synergistic fashion.

  19. Columbia University: Direct Reversal of Glucocorticoid Resistance by AKT inhibition in Acute Lymphoblastic Leukemia (T-ALL) | Office of Cancer Genomics

    Science.gov (United States)

    The goal of this project is to identify key druggable regulators of glucocorticoid resistance in T-ALL. To this end, a reverse-engineered T-ALL context-specific regulatory interaction network was created from a phenotypically diverse T-ALL gene expression dataset, and then this network was interrogated using master regulator analysis to find drivers of glucocorticoid resistance.

  20. Multi-nucleoside reverse transcriptase inhibitor resistant HIV type-1 in a patient from Sierra Leone failing stavudine, lamivudine and nevirapine

    NARCIS (Netherlands)

    Hamers, Raph L.; Wensing, Annemarie M. J.; Back, Nicole K. T.; Arcilla, Maria S.; Frissen, Jos P. H.

    2011-01-01

    We report a 33-year-old HIV type-1 (HIV-1)-infected male from Sierra Leone who harboured extensive drug resistance mutations to all nucleoside reverse transcriptase inhibitors (NRTIs) and non-NRTIs, including the multi-NRTI-resistance Q151M complex, K65R, M184I and Y181I, after using standard

  1. Limiting deoxynucleoside triphosphate concentrations emphasize the processivity defect of lamivudine-resistant variants of human immunodeficiency virus type 1 reverse transcriptase

    NARCIS (Netherlands)

    Back, N. K.; Berkhout, B.

    1997-01-01

    The nucleoside drug lamivudine (3TC) triggers the selection of resistant forms of the human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) with a substitution of amino acid 184Met. The 3TC-resistant RT enzymes 184Val and 184Ile exhibit a processivity defect in in vitro assays that

  2. Reversal of resistance in microorganisms by help of non-antibiotics

    DEFF Research Database (Denmark)

    Kristiansen, Jette E; Hendricks, Oliver; Delvin, Thomas

    2007-01-01

    Intracellular efflux pumps have been largely the research focus in multidrug-resistant (MDR) Gram-positive and Gram-negative microorganisms and parasites including cancers. However, drug efflux mechanisms other than pumps per se have been observed, supported by the effects of isomeric, non......-antibiotic DPR and ADPR, with the phospholipids being the initial sites attracting and concentrating the neurotropes to induce a form of suspended animation, followed by gross changes of cell wall and membrane structure, and thereby potentiating their destructive or immobilizing effects on various as yet only...... hinted at resistance and efflux mechanisms. Combination of appropriate isomeric non-antibiotic DPR and ADPR of low neurotropism and toxicity with conventional and classical antimicrobials promises early, new therapeutic strategies salutary against microbial resistance, resistance development...

  3. Identification of the critical sites of NNRTI-resistance in reverse transcriptase of HIV-1 CRF_BC strains.

    Directory of Open Access Journals (Sweden)

    Yang Huang

    Full Text Available BACKGROUND: The polymorphisms involved in drug resistance to non-nucleoside reverse transcriptase inhibitors (NNRTIs in HIV-1 CRF_BC, the most prevalent HIV-1 strain in China, have been poorly characterized. RESULTS: To reveal the drug resistance mutations, we compared the gene sequences of pol region of HIV-1 CRF_BC from 631 treatment-naïve and 363 treatment-experienced patients using the selection pressure-based method. We calculated an individual Ka/Ks value for each specific amino acid mutation. Result showed that eight polymorphic mutations (W88C, K101Q, I132L, R135L, T139K/R, H221Y and L228R in RT for treatment-experienced patients were identified, while they, except for R135L, were completely absent in those from treatment-naïve patients. The I132L and T139K/R mutants exhibited high-level resistance to DLV and NVP and moderate resistance to TMC-125 and EFV, while the K101Q and H221Y mutants exhibited an increased resistance to all four NNRTIs tested. The W88C, R135L, and L228R may be RTI-induced adaptive mutations. Y181C+K101Q mutant showed a 2.5-, 4.4-, and 4.7-fold higher resistance to TMC-125, NVP and EFV, respectively, than Y181C alone mutant, while Y181C+H221Y or K103N+H221Y mutants had significantly higher resistance to all four NNRTIs than Y181C or K103N mutants. K103N+T139K and G190A+T139K mutant induce higher resistance (2.0∼14.2-fold and 1.5∼7.2-fold, respectively to all four NNRTIs than K103N or G190A alone mutation. CONCLUSIONS: I132L and T139K/R are rare but critical mutations associated with NNRTI-resistance for some NNRTIs. K101Q, H221Y and T139K can enhance K103N/Y181C/G190A-assocated NNRTI-resistance. Monitoring these mutations will provide useful information for rational design of the NNRTI-based antiretroviral regimen for HIV-1 CRF_BC-infected patients.

  4. Go-6976 reverses hyperglycemia-induced insulin resistance independently of cPKC inhibition in adipocytes.

    Science.gov (United States)

    Robinson, Katherine A; Hegyi, Krisztina; Hannun, Yusuf A; Buse, Maria G; Sethi, Jaswinder K

    2014-01-01

    Chronic hyperglycemia induces insulin resistance by mechanisms that are incompletely understood. One model of hyperglycemia-induced insulin resistance involves chronic preincubation of adipocytes in the presence of high glucose and low insulin concentrations. We have previously shown that the mTOR complex 1 (mTORC1) plays a partial role in the development of insulin resistance in this model. Here, we demonstrate that treatment with Go-6976, a widely used "specific" inhibitor of cPKCs, alleviates hyperglycemia-induced insulin resistance. However, the effects of mTOR inhibitor, rapamycin and Go-6976 were not additive and only rapamycin restored impaired insulin-stimulated AKT activation. Although, PKCα, (but not -β) was abundantly expressed in these adipocytes, our studies indicate cPKCs do not play a major role in causing insulin-resistance in this model. There was no evidence of changes in the expression or phosphorylation of PKCα, and PKCα knock-down did not prevent the reduction of insulin-stimulated glucose transport. This was also consistent with lack of IRS-1 phosphorylation on Ser-24 in hyperglycemia-induced insulin-resistant adipocytes. Treatment with Go-6976 did inhibit a component of the mTORC1 pathway, as evidenced by decreased phosphorylation of S6 ribosomal protein. Raptor knock-down enhanced the effect of insulin on glucose transport in insulin resistant adipocytes. Go-6976 had the same effect in control cells, but was ineffective in cells with Raptor knock-down. Taken together these findings suggest that Go-6976 exerts its effect in alleviating hyperglycemia-induced insulin-resistance independently of cPKC inhibition and may target components of the mTORC1 signaling pathway.

  5. Go-6976 Reverses Hyperglycemia-Induced Insulin Resistance Independently of cPKC Inhibition in Adipocytes

    Science.gov (United States)

    Robinson, Katherine A.; Hegyi, Krisztina; Hannun, Yusuf A.; Buse, Maria G.; Sethi, Jaswinder K.

    2014-01-01

    Chronic hyperglycemia induces insulin resistance by mechanisms that are incompletely understood. One model of hyperglycemia-induced insulin resistance involves chronic preincubation of adipocytes in the presence of high glucose and low insulin concentrations. We have previously shown that the mTOR complex 1 (mTORC1) plays a partial role in the development of insulin resistance in this model. Here, we demonstrate that treatment with Go-6976, a widely used “specific” inhibitor of cPKCs, alleviates hyperglycemia-induced insulin resistance. However, the effects of mTOR inhibitor, rapamycin and Go-6976 were not additive and only rapamycin restored impaired insulin-stimulated AKT activation. Although, PKCα, (but not –β) was abundantly expressed in these adipocytes, our studies indicate cPKCs do not play a major role in causing insulin-resistance in this model. There was no evidence of changes in the expression or phosphorylation of PKCα, and PKCα knock-down did not prevent the reduction of insulin-stimulated glucose transport. This was also consistent with lack of IRS-1 phosphorylation on Ser-24 in hyperglycemia-induced insulin-resistant adipocytes. Treatment with Go-6976 did inhibit a component of the mTORC1 pathway, as evidenced by decreased phosphorylation of S6 ribosomal protein. Raptor knock-down enhanced the effect of insulin on glucose transport in insulin resistant adipocytes. Go-6976 had the same effect in control cells, but was ineffective in cells with Raptor knock-down. Taken together these findings suggest that Go-6976 exerts its effect in alleviating hyperglycemia-induced insulin-resistance independently of cPKC inhibition and may target components of the mTORC1 signaling pathway. PMID:25330241

  6. Ambroxol Hydrochloride Combined with Fluconazole Reverses the Resistance of Candida albicans to Fluconazole.

    Science.gov (United States)

    Li, Xiuyun; Zhao, Yuanhao; Huang, Xin; Yu, Cuixiang; Yang, Yilei; Sun, Shujuan

    2017-01-01

    In this study, we found that ambroxol hydrochloride (128 μg/mL) exhibits synergistic antifungal effects in combination with fluconazole (2 μg/mL) against resistant planktonic Candida albicans (C. albicans) cells. This combination also exhibited synergistic effects against resistant C. albicans biofilms in different stages (4, 8, and 12 h) according to the microdilution method. In vitro data were further confirmed by the success of this combination in treating Galleria mellonella infected by resistant C. albicans. With respect to the synergistic mechanism, our result revealed that ambroxol hydrochloride has an effect on the drug transporters of resistant C. albicans, increasing the uptake and decreasing the efflux of rhodamine 6G, a fluorescent alternate of fluconazole. This is the first study to investigate the in vitro and in vivo antifungal effects, as well as the possible synergistic mechanism of ambroxol hydrochloride in combination with fluconazole against resistant C. albicans. The results show the potential role for this drug combination as a therapeutic alternative to treat resistant C. albicans and provide insights into the development of antifungal targets and new antifungal agents.

  7. Targeting glucose metabolism in chondrosarcoma cells enhances the sensitivity to doxorubicin through the inhibition of lactate dehydrogenase-A.

    Science.gov (United States)

    Hua, Guojun; Liu, Yunpeng; Li, Xiangyong; Xu, Peirong; Luo, Yuchun

    2014-06-01

    Chondrosarcoma is a malignant cartilage-forming cancer composed of cells derived from transformed cells that produce cartilage. Conventional chemotherapy and radiotherapy have very limited efficacy in patients with advanced chondrosarcoma. In the present study, we reported a novel therapeutic approach in the treatment of chondrosarcoma cells. We detected that lactate dehydrogenase-A (LDHA) is highly active in chondrosarcoma cells and chondrosarcoma patient samples compared with normal chondrocyte cell lines and primary human chondrocyte. Moreover, chondrosarcoma cells exhibited elevated levels of LDHA expression under doxorubicin treatment. To further explore the mechanisms, we generated doxorubicin-resistant cells from SW1353 chondrosarcoma cell line. Notably, the activity and expression of LDHA are upregulated in doxorubicin-resistant cells. Moreover, our data showed a strong correlation between glucose metabolism and doxorubicin resistance in chondrosarcoma cells; doxorubicin-resistant cells displayed highly activated glucose metabolism and depended more on glucose supply. Finally, we reported a synergistic effect produced by incorporating doxorubicin with glycolysis inhibitors-oxamate in the combined treatment of chondrosarcoma cells in vitro and in vivo. In summary, the present study may aid in the development of new approaches using the combination of chemotherapeutic agents for the treatment of chondrosarcoma patients.

  8. Osimertinib (AZD9291, a Mutant-Selective EGFR Inhibitor, Reverses ABCB1-Mediated Drug Resistance in Cancer Cells

    Directory of Open Access Journals (Sweden)

    Xiao-Yu Zhang

    2016-09-01

    Full Text Available In recent years, tyrosine kinase inhibitors (TKIs have been shown capable of inhibiting the ATP-binding cassette (ABC transporter-mediated multidrug resistance (MDR. In this study, we determine whether osimertinib, a novel selective, irreversible EGFR (epidermal growth factor receptor TKI, could reverse ABC transporter-mediated MDR. The results showed that, at non-toxic concentrations, osimertinib significantly sensitized both ABCB1-transfected and drug-selected cell lines to substrate anticancer drugs colchicine, paclitaxel, and vincristine. Osimertinib significantly increased the accumulation of [3H]-paclitaxel in ABCB1 overexpressing cells by blocking the efflux function of ABCB1 transporter. In contrast, no significant alteration in the expression levels and localization pattern of ABCB1 was observed when ABCB1 overexpressing cells were exposed to 0.3 µM osimertinib for 72 h. In addition, ATPase assay showed osimertinib stimulated ABCB1 ATPase activity. Molecular docking and molecular dynamic simulations showed osimertinib has strong and stable interactions at the transmembrane domain of human homology ABCB1. Taken together, our findings suggest that osimertinib, a clinically-approved third-generation EGFR TKI, can reverse ABCB1-mediated MDR, which supports the combination therapy with osimertinib and ABCB1 substrates may potentially be a novel therapeutic stategy in ABCB1-positive drug resistant cancers.

  9. Treatment of acquired drug resistance in multiple myeloma by combination therapy with XPO1 and topoisomerase II inhibitors.

    Science.gov (United States)

    Turner, Joel G; Dawson, Jana L; Grant, Steven; Shain, Kenneth H; Dalton, William S; Dai, Yun; Meads, Mark; Baz, Rachid; Kauffman, Michael; Shacham, Sharon; Sullivan, Daniel M

    2016-08-24

    Acquired drug resistance is the greatest obstacle to the successful treatment of multiple myeloma (MM). Despite recent advanced treatment options such as liposomal formulations, proteasome inhibitors, immunomodulatory drugs, myeloma-targeted antibodies, and histone deacetylase inhibitors, MM is still considered an incurable disease. We investigated whether the clinical exportin 1 (XPO1) inhibitor selinexor (KPT-330), when combined with pegylated liposomal doxorubicin (PLD) or doxorubicin hydrochloride, could overcome acquired drug resistance in multidrug-resistant human MM xenograft tumors, four different multidrug-resistant MM cell lines, or ex vivo MM biopsies from relapsed/refractory patients. Mechanistic studies were performed to assess co-localization of topoisomerase II alpha (TOP2A), DNA damage, and siRNA knockdown of drug targets. Selinexor was found to restore sensitivity of multidrug-resistant 8226B25, 8226Dox6, 8226Dox40, and U266PSR human MM cells to doxorubicin to levels found in parental myeloma cell lines. NOD/SCID-γ mice challenged with drug-resistant or parental U266 human MM and treated with selinexor/PLD had significantly decreased tumor growth and increased survival with minimal toxicity. Selinexor/doxorubicin treatment selectively induced apoptosis in CD138/light-chain-positive MM cells without affecting non-myeloma cells in ex vivo-treated bone marrow aspirates from newly diagnosed or relapsed/refractory MM patients. Selinexor inhibited XPO1-TOP2A protein complexes (proximity ligation assay), preventing nuclear export of TOP2A in both parental and multidrug-resistant MM cell lines. Selinexor/doxorubicin treatment significantly increased DNA damage (comet assay/γ-H2AX) in both parental and drug-resistant MM cells. TOP2A knockdown reversed both the anti-tumor effect and significantly reduced DNA damage induced by selinexor/doxorubicin treatment. The combination of an XPO1 inhibitor and liposomal doxorubicin was highly effective against

  10. Treatment of acquired drug resistance in multiple myeloma by combination therapy with XPO1 and topoisomerase II inhibitors

    Directory of Open Access Journals (Sweden)

    Joel G. Turner

    2016-08-01

    Full Text Available Abstract Background Acquired drug resistance is the greatest obstacle to the successful treatment of multiple myeloma (MM. Despite recent advanced treatment options such as liposomal formulations, proteasome inhibitors, immunomodulatory drugs, myeloma-targeted antibodies, and histone deacetylase inhibitors, MM is still considered an incurable disease. Methods We investigated whether the clinical exportin 1 (XPO1 inhibitor selinexor (KPT-330, when combined with pegylated liposomal doxorubicin (PLD or doxorubicin hydrochloride, could overcome acquired drug resistance in multidrug-resistant human MM xenograft tumors, four different multidrug-resistant MM cell lines, or ex vivo MM biopsies from relapsed/refractory patients. Mechanistic studies were performed to assess co-localization of topoisomerase II alpha (TOP2A, DNA damage, and siRNA knockdown of drug targets. Results Selinexor was found to restore sensitivity of multidrug-resistant 8226B25, 8226Dox6, 8226Dox40, and U266PSR human MM cells to doxorubicin to levels found in parental myeloma cell lines. NOD/SCID-γ mice challenged with drug-resistant or parental U266 human MM and treated with selinexor/PLD had significantly decreased tumor growth and increased survival with minimal toxicity. Selinexor/doxorubicin treatment selectively induced apoptosis in CD138/light-chain-positive MM cells without affecting non-myeloma cells in ex vivo-treated bone marrow aspirates from newly diagnosed or relapsed/refractory MM patients. Selinexor inhibited XPO1-TOP2A protein complexes (proximity ligation assay, preventing nuclear export of TOP2A in both parental and multidrug-resistant MM cell lines. Selinexor/doxorubicin treatment significantly increased DNA damage (comet assay/γ-H2AX in both parental and drug-resistant MM cells. TOP2A knockdown reversed both the anti-tumor effect and significantly reduced DNA damage induced by selinexor/doxorubicin treatment. Conclusions The combination of an XPO1 inhibitor

  11. β-elemene reverses the drug resistance of lung cancer A549/DDP cells via the mitochondrial apoptosis pathway.

    Science.gov (United States)

    Yao, Cheng-Cai; Tu, Yuan-Rong; Jiang, Jie; Ye, Sheng-Fang; Du, Hao-Xin; Zhang, Yi

    2014-05-01

    β-elemene (β-ELE) is a new anticancer drug extracted from Curcuma zedoaria Roscoe and has been widely used to treat malignant tumors. Recent studies have demonstrated that β-ELE reverses the drug resistance of tumor cells. To explore the possible mechanisms of action of β-ELE, we investigated its effects on cisplatin-resistant human lung adenocarcinoma A549/DDP cells. The effects of β-ELE on the growth of A549/DDP cells in vitro were determined by MTT assay. Apoptosis was assessed by fluorescence microscopy with Hoechst 33258 staining and flow cytometry with Annexin V-FITC/PI double staining. Mitochondrial membrane potential was assessed using JC-1 fluorescence probe and laser confocal scanning microscopy, and intracellular reactive oxygen species levels were measured by 2',7'-dichlorofluorescein-diacetate staining and flow cytometry. Cytosolic glutathione content was determined using GSH kits. The expression of cytochrome c, caspase-3, procaspase-3 and the Bcl-2 family proteins was assessed by western blotting. The results demonstrated that β-ELE inhibited the proliferation of A549/DDP cells in a time- and dose-dependent manner. Furthermore, β-ELE enhanced the sensitivity of A549/DDP cells to cisplatin and reversed the drug resistance of A549/DDP cells. Consistent with a role in activating apoptosis, β-ELE decreased mitochondrial membrane potential, increased intracellular reactive oxygen species concentration and decreased the cytoplasmic glutathione levels in a time- and dose-dependent manner. The combination of β-ELE and cisplatin enhanced the protein expression of cytochrome c, caspase-3 and Bad, and reduced protein levels of Bcl-2 and procaspase-3 in the A549/DDP lung cancer cells. These results define a pathway of procaspase‑3-β-ELE function that involves decreased mitochondrial membrane potential, leading to apoptosis triggered by the release of cytochrome c into the cytoplasm and the modulation of apoptosis-related genes. The reversal of drug

  12. Doxorubicin in combination with a small TGFbeta inhibitor: a potential novel therapy for metastatic breast cancer in mouse models.

    Directory of Open Access Journals (Sweden)

    Abhik Bandyopadhyay

    2010-04-01

    Full Text Available Recent studies suggested that induction of epithelial-mesenchymal transition (EMT might confer both metastatic and self-renewal properties to breast tumor cells resulting in drug resistance and tumor recurrence. TGFbeta is a potent inducer of EMT and has been shown to promote tumor progression in various breast cancer cell and animal models.We report that chemotherapeutic drug doxorubicin activates TGFbeta signaling in human and murine breast cancer cells. Doxorubicin induced EMT, promoted invasion and enhanced generation of cells with stem cell phenotype in murine 4T1 breast cancer cells in vitro, which were significantly inhibited by a TGFbeta type I receptor kinase inhibitor (TbetaRI-KI. We investigated the potential synergistic anti-tumor activity of TbetaR1-KI in combination with doxorubicin in animal models of metastatic breast cancer. Combination of Doxorubicin and TbetaRI-KI enhanced the efficacy of doxorubicin in reducing tumor growth and lung metastasis in the 4T1 orthotopic xenograft model in comparison to single treatments. Doxorubicin treatment alone enhanced metastasis to lung in the human breast cancer MDA-MB-231 orthotopic xenograft model and metastasis to bone in the 4T1 orthotopic xenograft model, which was significantly blocked when TbetaR1-KI was administered in combination with doxorubicin.These observations suggest that the adverse activation of TGFbeta pathway by chemotherapeutics in the cancer cells together with elevated TGFbeta levels in tumor microenvironment may lead to EMT and generation of cancer stem cells resulting in the resistance to the chemotherapy. Our results indicate that the combination treatment of doxorubicin with a TGFbeta inhibitor has the potential to reduce the dose and consequently the toxic side-effects of doxorubicin, and improve its efficacy in the inhibition of breast cancer growth and metastasis.

  13. Reversal of resistance in bacteria underlies synergistic effect of essential oils with conventional antibiotics.

    Science.gov (United States)

    Lahmar, Aida; Bedoui, Ahmed; Mokdad-Bzeouich, Imen; Dhaouifi, Zaineb; Kalboussi, Zahar; Cheraif, Imed; Ghedira, Kamel; Chekir-Ghedira, Leila

    2017-05-01

    The pervasive of bacterial resistance earnestly threaten the prevention and the treatment of infectious diseases. Therefore, scientific communities take precedence over development of new antimicrobial agents. The aim of the study was to determine antimicrobial potency of three North-African essential oils Pituranthos chloranthus, Teucruim ramosissimum and Pistacia lentiscus individually, and in combination with antibiotics, to inhibit the growth of highly resistant clinical pathogen. Bacteria clinically isolated from patients, subsequently, challenged to a panel of drugs to determine the antibiotic-resistance profiles. Drugs displaying clinically irrelevant CMI were subjected to further studies in order to rescue antibiotic actions. Singular activity of essential oils and activity when combined with an antibiotic was hence elucidated. The results obtained highlighted the occurrence of strong antibacterial potential of essential oils when administrated alone. In the interactive experiment essential oils were found highly effective in reducing the resistance of Methicillin-resistant Staphylococcus aureus to amoxicillin, tetracycline, piperacillin, ofloxacin and oxacillin and resistance of Acinetobacter baumannii to amoxicillin and to ofloxacin in interactive manner. Furthermore, the results proved synergism among essential oils and both antibiotics ofloxacin and novobiocin against the Extended-Spectrum Beta-Lactamase producing E. coli (ESBL). Time kill kinetics was performed with a combination of sub-inhibitory concentrations to confirm the efficiency and killing rate of the combination over time. Further, the hypothetical toxicity of essential oils against human keratinocytes HaCat and murine spleenocytes were examined. The chemical composition of essential oils was assessed by GC/MS analysis and the major constituents found were sabinene, limonene, terpinen-4-ol, and β-eudesmol. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Pegylated liposomal doxorubicin: a review of its use in metastatic breast cancer, ovarian cancer, multiple myeloma and AIDS-related Kaposi's sarcoma.

    Science.gov (United States)

    Duggan, Sean T; Keating, Gillian M

    2011-12-24

    Pegylated liposomal doxorubicin (Caelyx™, Doxil®) represents an improved formulation of conventional doxorubicin, with reduced cardiotoxicity and an improved pharmacokinetic profile. This article reviews the efficacy and tolerability of pegylated liposomal doxorubicin in metastatic breast cancer, progressive ovarian cancer, relapsed or refractory multiple myeloma and AIDS-related Kaposi's sarcoma, as well as summarizing its pharmacological properties. In three randomized, open-label, multicentre trials, monotherapy with pegylated liposomal doxorubicin was as effective as doxorubicin or capecitabine in the first-line treatment of metastatic breast cancer, and as effective as vinorelbine or combination mitomycin plus vinblastine in taxane-refractory metastatic breast cancer. Pegylated liposomal doxorubicin alone was as effective as topotecan or gemcitabine alone in patients with progressive ovarian cancer resistant or refractory to platinum- or paclitaxel-based therapy, according to the results of three randomized multicentre trials. In addition, in patients with progressive ovarian cancer who had received prior platinum-based therapy, progression-free survival was significantly longer with pegylated liposomal doxorubicin plus carboplatin than with paclitaxel plus carboplatin, according to the results of a randomized, open-label multicentre trial. Combination therapy with pegylated liposomal doxorubicin plus bortezomib was more effective than bortezomib alone in patients with relapsed or refractory multiple myeloma, according to the results of a randomized, open-label, multinational trial. Randomized multinational trials also demonstrated the efficacy of pegylated liposomal doxorubicin in patients with advanced AIDS-related Kaposi's sarcoma. Pegylated liposomal doxorubicin exhibited a relatively favourable safety profile compared with conventional doxorubicin and other available chemotherapy agents. The most common treatment-related adverse events included

  15. Efficient Reverse Transcription Using Locked Nucleic Acid Nucleotides towards the Evolution of Nuclease Resistant RNA Aptamers

    DEFF Research Database (Denmark)

    Crouzier, Lucile; Dubois, Camille; Edwards, Stacey L

    2012-01-01

    Modified nucleotides are increasingly being utilized in the de novo selection of aptamers for enhancing their drug-like character and abolishing the need for time consuming trial-and-error based post-selection modifications. Locked nucleic acid (LNA) is one of the most prominent and successful...... nucleic acid analogues because of its remarkable properties, and widely explored as building blocks in therapeutic oligonucleotides. Evolution of LNA-modified RNA aptamers requires an efficient reverse transcription method for PCR enrichment of the selected RNA aptamer candidates. Establishing this key...... step is a pre-requisite for performing LNA-modified RNA aptamer selection....

  16. Reverse Transcriptase drug resistance mutations in HIV-1 Subtype C infected patients on ART in Karonga District, Malawi

    LENUS (Irish Health Repository)

    Bansode, Vijay B

    2011-10-13

    Abstract Background Drug resistance testing before initiation of, or during, antiretroviral therapy (ART) is not routinely performed in resource-limited settings. High levels of viral resistance circulating within the population will have impact on treatment programs by increasing the chances of transmission of resistant strains and treatment failure. Here, we investigate Drug Resistance Mutations (DRMs) from blood samples obtained at regular intervals from patients on ART (Baseline-22 months) in Karonga District, Malawi. One hundred and forty nine reverse transcriptase (RT) consensus sequences were obtained via nested PCR and automated sequencing from blood samples collected at three-month intervals from 75 HIV-1 subtype C infected individuals in the ART programme. Results Fifteen individuals showed DRMs, and in ten individuals DRMs were seen from baseline samples (reported to be ART naïve). Three individuals in whom no DRMs were observed at baseline showed the emergence of DRMs during ART exposure. Four individuals who did show DRMs at baseline showed additional DRMs at subsequent time points, while two individuals showed evidence of DRMs at baseline and either no DRMs, or different DRMs, at later timepoints. Three individuals had immune failure but none appeared to be failing clinically. Conclusion Despite the presence of DRMs to drugs included in the current regimen in some individuals, and immune failure in three, no signs of clinical failure were seen during this study. This cohort will continue to be monitored as part of the Karonga Prevention Study so that the long-term impact of these mutations can be assessed. Documenting proviral population is also important in monitoring the emergence of drug resistance as selective pressure provided by ART compromises the current plasma population, archived viruses can re-emerge

  17. Identification of a novel resistance (E40F and compensatory (K43E substitution in HIV-1 reverse transcriptase

    Directory of Open Access Journals (Sweden)

    Kagan Ron M

    2008-02-01

    Full Text Available Abstract Background HIV-1 nucleoside reverse transcriptase inhibitors (NRTIs have been used in the clinic for over twenty years. Interestingly, the complete resistance pattern to this class has not been fully elucidated. Novel mutations in RT appearing during treatment failure are still being identified. To unravel the role of two of these newly identified changes, E40F and K43E, we investigated their effect on viral drug susceptibility and replicative capacity. Results A large database (Quest Diagnostics database was analysed to determine the associations of the E40F and K43E changes with known resistance mutations. Both amino acid changes are strongly associated with the well known NRTI-resistance mutations M41L, L210W and T215Y. In addition, a strong positive association between these changes themselves was observed. A panel of recombinant viruses was generated by site-directed mutagenesis and phenotypically analysed. To determine the effect on replication capacity, competition and in vitro evolution experiments were performed. Introduction of E40F results in an increase in Zidovudine resistance ranging from nine to fourteen fold depending on the RT background and at the same time confers a decrease in viral replication capacity. The K43E change does not decrease the susceptibility to Zidovudine but increases viral replication capacity, when combined with E40F, demonstrating a compensatory role for this codon change. Conclusion In conclusion, we have identified a novel resistance (E40F and compensatory (K43E change in HIV-1 RT. Further research is indicated to analyse the clinical importance of these changes.

  18. Nuclear receptors reverse McGarry's vicious cycle to insulin resistance

    Science.gov (United States)

    Several pathways and pathologies have been suggested as connections between obesity and diabetes, including inflammation of adipose and other tissues, toxic lipids, endoplasmic reticulum stress, and fatty liver. One specific proposal is that insulin resistance induces a vicious cycle in which hyperi...

  19. Reversal of diet-induced obesity and insulin resistance by inducible genetic ablation of GRK2

    NARCIS (Netherlands)

    Vila-Bedmar, Rocio; Cruces-Sande, Marta; Lucas, Elisa; Willemen, Hanneke L D M; Heijnen, Cobi J; Kavelaars, Annemieke; Mayor, Federico; Murga, Cristina

    2015-01-01

    Insulin resistance is a common feature of obesity and predisposes individuals to various prevalent pathological conditions. G protein (heterotrimeric guanine nucleotide-binding protein)-coupled receptor kinase 2 (GRK2) integrates several signal transduction pathways and is emerging as a

  20. Reversible Changes in Resistance of Perovskite Nickelate NdNiO3Thin Films Induced by Fluorine Substitution.

    Science.gov (United States)

    Onozuka, Tomoya; Chikamatsu, Akira; Katayama, Tsukasa; Hirose, Yasushi; Harayama, Isao; Sekiba, Daiichiro; Ikenaga, Eiji; Minohara, Makoto; Kumigashira, Hiroshi; Hasegawa, Tetsuya

    2017-03-29

    Perovskite nickel oxides are of fundamental as well as technological interest because they show large resistance modulation associated with phase transition as a function of the temperature and chemical composition. Here, the effects of fluorine doping in perovskite nickelate NdNiO 3 epitaxial thin films are investigated through a low-temperature reaction with polyvinylidene fluoride as the fluorine source. The fluorine content in the fluorinated NdNiO 3-x F x films is controlled with precision by varying the reaction time. The fully fluorinated film (x ≈ 1) is highly insulating and has a bandgap of 2.1 eV, in contrast to NdNiO 3 , which exhibits metallic transport properties. Hard X-ray photoelectron and soft X-ray absorption spectroscopies reveal the suppression of the density of states at the Fermi level as well as the reduction of nickel ions (valence state changes from +3 to +2) after fluorination, suggesting that the strong Coulombic repulsion in the Ni 3d orbitals associated with the fluorine substitution drives the metal-to-insulator transition. In addition, the resistivity of the fluorinated films recovers to the original value for NdNiO 3 after annealing in an oxygen atmosphere. By application of the reversible fluorination process to transition-metal oxides, the search for resistance-switching materials could be accelerated.

  1. Novel reverse osmosis membranes composed of modified PVA/Gum Arabic conjugates: Biofouling mitigation and chlorine resistance enhancement.

    Science.gov (United States)

    Falath, Wail; Sabir, Aneela; Jacob, Karl I

    2017-01-02

    A novel crosslinked Poly (vinyl alcohol) (PVA) reverse osmosis (RO) thin film membrane conjugated with Gum Arabic (GA) with superb performance and features was synthesized for water desalination. RO membrane desalination parameters, such as hydrophilicity, surface roughness, water permeability, salt rejection, Chlorine resistance and biofouling resistance were evaluated using a dead end RO filtration unit. The incorporation of Pluronic F127 and the conjugation of Gum Arabic improved the overall RO performance of the membranes. This study has shown that the membrane PVA-GA-5 that contains 0.9wt% Gum Arabic provided excellent permeation, salt rejection, Chlorine and biofouling resistance and mechanical strength. The most remarkable result to arise from this research is that the overall RO performance enhancement has been achieved while utilizing PVA/Gum Arabic as a separation layer without the use of a substrate, which eliminates negative effects associated with the use of a substrate like internal concentration polarization. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Folic acid ameliorates celecoxib cardiotoxicity in a doxorubicin heart failure rat model.

    Science.gov (United States)

    Ahmad, Shafique; Panda, Bibhu Prasad; Kohli, Kanchan; Fahim, Mohammad; Dubey, Kiran

    2017-12-01

    The cardiotoxic effect of selective cyclo-oxygenase-2 inhibitors is well known. While rofecoxib and valdecoxib have been withdrawn, celecoxib remains on the market. Folic acid, a naturally occurring vitamin, has been shown to reduce myocardial ischemia and post-reperfusion injury in rats. This study examined the cardiac effects of celecoxib and folic acid on doxorubicin-induced cardiomyopathy in rats. Cardiomyopathy was induced in male Wistar rats with six intraperitoneal injections of 2.5 mg/kg doxorubicin over a period of two weeks. The effect of 28 days of celecoxib (100 mg/kg/day) and its combination with folic acid (10 mg/kg/day) was studied on doxorubicin-induced cardiomyopathy according to serum lactate dehydrogenase (LDH), creatine kinase (CK-MB), troponin-T (Tn-T), tumor necrosis factor alpha (TNF-α), cardiac thiobarbituric acid reactive substance (TBARS), and glutathione (GSH) levels as well as systolic blood pressure (SBP), heart rate (HR) and ultrastructural studies. Celecoxib cardiotoxicity was manifested by significant increases in the LDH, Tn-T, TNF-α, CK-MB, SBP, HR (p folic acid with celecoxib caused a significant reversal of these parameters and reduced the cardiotoxicity of celecoxib that was aggravated by doxorubicin. The ultrastructural study also revealed myocardial protection with this combination. Folic acid protects against the cardiotoxic effects of celecoxib, which are aggravated in the presence of doxorubicin. Folic acid may act as a useful adjunct in patients who are taking celecoxib.

  3. Shock-Resistibility of MEMS-Based Inertial Microswitch under Reverse Directional Ultra-High g Acceleration for IoT Applications

    Science.gov (United States)

    Xu, Qiu; Yang, Zhuoqing; Sun, Yunna; Lai, Liyan; Jin, Zhiyu; Ding, Guifu; Zhao, Xiaolin; Yao, Jinyuan; Wang, Jing

    2017-03-01

    This paper presents a novel MEMS-based inertial microswitch design with multi-directional compact constraint structures for improving the shock-resistibility. Its shock-resistibility in the reverse-sensitive direction to ultra-high g acceleration (~hunderds of thousands) is simulated and analyzed. The dynamic response process indicates that in the designed inertial microswitch the proof mass weight G, the whole system’s stiffness k and the gap x2 between the proof mass and reverse constraint blocks have significant effect on the shock-resistibility. The MEMS inertial microswitch micro-fabricated by surface micromachining has been evaluated using the drop hammer test. The maximum allowable reverse acceleration, which does not cause the spurious trigger, is defined as the reverse acceleration threshold (athr). Test results show that athr increases with the decrease of the gap x2, and the proposed microswitch tends to have a better shock-resistibility under smaller gap. The measured responses of the microswitches with and without constraint structure indicates that the device without constraint structure is prone to spurious trigger, while the designed constraint structures can effectively improve the shock-resistibility. In this paper, the method for improving the shock-resistibility and reducing the spurious trigger has been discussed.

  4. Shock-Resistibility of MEMS-Based Inertial Microswitch under Reverse Directional Ultra-High g Acceleration for IoT Applications.

    Science.gov (United States)

    Xu, Qiu; Yang, Zhuoqing; Sun, Yunna; Lai, Liyan; Jin, Zhiyu; Ding, Guifu; Zhao, Xiaolin; Yao, Jinyuan; Wang, Jing

    2017-03-31

    This paper presents a novel MEMS-based inertial microswitch design with multi-directional compact constraint structures for improving the shock-resistibility. Its shock-resistibility in the reverse-sensitive direction to ultra-high g acceleration (~hunderds of thousands) is simulated and analyzed. The dynamic response process indicates that in the designed inertial microswitch the proof mass weight G, the whole system's stiffness k and the gap x2 between the proof mass and reverse constraint blocks have significant effect on the shock-resistibility. The MEMS inertial microswitch micro-fabricated by surface micromachining has been evaluated using the drop hammer test. The maximum allowable reverse acceleration, which does not cause the spurious trigger, is defined as the reverse acceleration threshold (athr). Test results show that athr increases with the decrease of the gap x2, and the proposed microswitch tends to have a better shock-resistibility under smaller gap. The measured responses of the microswitches with and without constraint structure indicates that the device without constraint structure is prone to spurious trigger, while the designed constraint structures can effectively improve the shock-resistibility. In this paper, the method for improving the shock-resistibility and reducing the spurious trigger has been discussed.

  5. N348I in the connection domain of HIV-1 reverse transcriptase confers zidovudine and nevirapine resistance.

    Directory of Open Access Journals (Sweden)

    Soo-Huey Yap

    2007-12-01

    Full Text Available The catalytically active 66-kDa subunit of the human immunodeficiency virus type 1 (HIV-1 reverse transcriptase (RT consists of DNA polymerase, connection, and ribonuclease H (RNase H domains. Almost all known RT inhibitor resistance mutations identified to date map to the polymerase domain of the enzyme. However, the connection and RNase H domains are not routinely analysed in clinical samples and none of the genotyping assays available for patient management sequence the entire RT coding region. The British Columbia Centre for Excellence in HIV/AIDS (the Centre genotypes clinical isolates up to codon 400 in RT, and our retrospective statistical analyses of the Centre's database have identified an N348I mutation in the RT connection domain in treatment-experienced individuals. The objective of this multidisciplinary study was to establish the in vivo relevance of this mutation and its role in drug resistance.The prevalence of N348I in clinical isolates, the time taken for it to emerge under selective drug pressure, and its association with changes in viral load, specific drug treatment, and known drug resistance mutations was analysed from genotypes, viral loads, and treatment histories from the Centre's database. N348I increased in prevalence from below 1% in 368 treatment-naïve individuals to 12.1% in 1,009 treatment-experienced patients (p = 7.7 x 10(-12. N348I appeared early in therapy and was highly associated with thymidine analogue mutations (TAMs M41L and T215Y/F (p < 0.001, the lamivudine resistance mutations M184V/I (p < 0.001, and non-nucleoside RTI (NNRTI resistance mutations K103N and Y181C/I (p < 0.001. The association with TAMs and NNRTI resistance mutations was consistent with the selection of N348I in patients treated with regimens that included both zidovudine and nevirapine (odds ratio 2.62, 95% confidence interval 1.43-4.81. The appearance of N348I was associated with a significant increase in viral load (p < 0.001, which

  6. Overcoming immunoescape mechanisms of BCL1 leukemia and induction of CD8+ T-cell-mediated BCK1-specific resistance in mice cured by targeted polymer-bound doxorubicin

    Czech Academy of Sciences Publication Activity Database

    Kovář, Marek; Tomala, Jakub; Chmelová, Helena; Kovář, Lubomír; Mrkvan, Tomáš; Josková, Radka; Zákostelská, Zuzana; Etrych, Tomáš; Strohalm, Jiří; Ulbrich, Karel; Šírová, Milada; Říhová, Blanka

    2008-01-01

    Roč. 68, č. 23 (2008), s. 9875-9883 ISSN 0008-5472 R&D Projects: GA MŠk 1M0505; GA ČR GP301/07/P192; GA ČR GD310/08/H077; GA AV ČR IAAX00500803 Institutional research plan: CEZ:AV0Z50200510; CEZ:AV0Z40500505 Keywords : tumor * bcl1 leukemia * doxorubicin Subject RIV: EC - Immunology Impact factor: 7.514, year: 2008

  7. Polarity reversion of the operation mode of HfO2-based resistive random access memory devices by inserting Hf metal layer.

    Science.gov (United States)

    Peng, Ching-Shiang; Chang, Wen-Yuan; Lin, Ming-Ho; Chen, Wei-Su; Chen, Frederick; Tsai, Ming-Jinn

    2013-03-01

    The reversion of polarity within bipolar resistive switching operation occurs in Pt/HfO2/TiN and Pt/Hf/HfO2/TiN resistive random access memory devices. This reversion of voltage polarity is the result of interface generation which induces a conduction mechanism transformation from Poole-Frenkel emission to space charge limited current mechanism. To prove the reversion of polarity, this study uses curve fitting of I-V relations to verify the conduction mechanism theoretically and physical analysis to verify the oxygen ion distribution practically. The proposed Pt/Hf/HfO2/TiN devices exhibit good resistive switching characteristics, such as good uniformity, low voltage operation, robust endurance (10(3) dc sweep), and long retention (3 x 10(4) s at 85 degrees C).

  8. Biosynthesis of Phenylnannolone A, a Multidrug Resistance Reversal Agent from the Halotolerant Myxobacterium Nannocystis pusilla B150

    DEFF Research Database (Denmark)

    Bouhired, Sarah M.; Crüsemann, Max; Almeida, Celso

    2014-01-01

    . Phn1 is a putative butyryl‐CoA carboxylase (BCC), providing ethylmalonyl‐CoA for the formation of the ethyl‐substituted part of phenylnannolone A. Phn1 is the first BCC found in biosynthetic genes for an ethyl‐substituted natural compound. Biosynthesis of phenylnannolone A, putatively encoded by phn1......The myxobacterial strain Nannocystis pusilla B150 synthesizes the structurally new polyketides phenylnannolone A–C. Apart from some common volatiles and siderophores, these are the first natural products from the genus Nannocystis. Phenylnannolone A shows inhibitory activity towards the ABCB1 gene...... product P‐glycoprotein and reverses daunorubicin resistance in cancer cells. To decipher the biochemical reactions leading to the formation of phenylnannolone A, the putative biosynthetic genes were identified (phn1, phn2). Phn2 is a polyketide synthase (PKS) with an NRPS‐like loading module, and its...

  9. Epigenetic therapy with hydralazine and magnesium valproate reverses imatinib resistance in patients with chronic myeloid leukemia.

    Science.gov (United States)

    Cervera, Eduardo; Candelaria, Myrna; López-Navarro, Omar; Labardini, Juan; Gonzalez-Fierro, Aurora; Taja-Chayeb, Lucia; Cortes, Jorge; Gordillo-Bastidas, Daniela; Dueñas-González, Alfonso

    2012-06-01

    The epigenetic drugs hydralazine and valproate were administered in a compassionate manner to 8 patients with chronic myeloid leukemia (CML) refractory to imatinib. Two patients had a complete hematologic response (25%),1 major cytogenetic response, 1 complete cytogenetic response (25% any cytogenetic response), and 3 (37.5%)stable disease. No grade 3 or 4 toxicity was observed. These results show the ability of epigenetic therapy to revert imatinib resistance. Epigenetic alterations participate in the development of acquired resistance to imatinib, hence, the DNA methylation, and histone deacetylase inhibitors hydralazine and valproate, respectively, has the potential to overcome it. A series of 8 patients with chronic myeloid leukemia (CML) refractory to imatinib mesylate with no access to second-generation tyrosine kinase inhibitors were treated with hydralazine and valproate in a compassionate manner. Clinical efficacy and safety of these drugs added to imatinib mesylate were evaluated. Two patients were in the blast phase, 5 were in the accelerated phase, and 1 was in the chronic phase. All the patients continued with the same dose of imatinib that they had been receiving at the time of development of resistance, with a median dose of 600 mg daily (range, 400-800 mg). The median time from diagnosis of CML to the start of hydralazine and valproate was 53.6 months (range, 19-84 months). Two (25%) patients had a complete hematologic response, one (12.5%) had an major cytogenetic response, and one (12.5%) had a complete cytogenetic response. Three (37.5%) patients had stable disease, and only one (12.5%) patient failed to respond. At a median follow-up time of 18 months (range, 3-18 months), the median survival had not been reached, and the projected overall survival was 63%. All the patients had mild neurologic toxicity, including distal tremor and somnolence. No grade 3 or 4 toxicity was observed. Our results suggest that the epigenetic drugs hydralazine and

  10. Antisense expression of PKCα improved sensitivity of SGC7901/VCR cells to doxorubicin

    Science.gov (United States)

    Wu, Da-Long; Sui, Feng-Ying; Du, Cheng; Zhang, Cheng-Wen; Hui, Bin; Xu, Shui-Ling; Lu, Huan-Zhang; Song, Guo-Jie

    2009-01-01

    AIM: To explore whether antisense blocking of protein kinase C alpha (PKCα) would reverse multi-drug resistance (MDR) in the vincristine (VCR)-resistant human gastric cancer cell line SGC7901/VCR. METHODS: SGC7901/VCR cells expressing antisense PKCα, SGC7901/VCR/aPKC, were established by transfection with a recombinant plasmid reversely inserted with PKCα cDNA. Empty vector (PCI-neo)-transfected cell clones, SGC7901/VCR/neo, served as the control. Western blot method was used to detect PKCα content in SGC7901, SGC7901/VCR, SGC7901/VCR/neo and SGC7901/VCR/aPKC cells, using PKCα-specific antibody. The sensitivity of SGC7901, SGC7901/VCR, SGC7901/VCR/neo and SGC7901/VCR/aPKC cells to doxorubicin (DOX) in vitro was determined by MTT assay. The uptake of DOX in these cells was detected with fluorescence spectrophotometer. RESULTS: Western blot analysis showed that the PKCα protein level was about 8.7-fold higher in SGC7901/VCR cells than that in SGC7901 cells, whereas the protein expression of PKCα was reduced by 78% in SGC7901/VCR/aPKC cells when compared with the SGC7901/VCR cells. SGC7901/VCR/aPKC cells had a 4.2-fold increase in DOX cytotoxicity, accompanied by a 1.7-fold increase of DOX accumulation in comparison with SGC7901/VCR cells. CONCLUSION: PKCα positively regulates MDR in SGC7901 cells, and inhibition of PKCα can partially attenuate MDR in human gastric cancer cells. PMID:19291828

  11. UVRAG Deficiency Exacerbates Doxorubicin-Induced Cardiotoxicity

    Science.gov (United States)

    An, Lin; Hu, Xiao-wen; Zhang, Shasha; Hu, Xiaowen; Song, Zongpei; Naz, Amber; Zi, Zhenguo; Wu, Jian; Li, Can; Zou, Yunzeng; He, Lin; Zhu, Hongxin

    2017-01-01

    Doxorubicin (DOX) is an effective chemotherapeutic drug in the treatment of various types of cancers. However, its clinical application has been largely limited by potential development of cardiotoxicity. Previously we have shown that ultra-violet radiation resistance-associated gene (UVRAG), an autophagy-related protein, is essential for the maintenance of autophagic flux in the heart under physiological conditions. Here, we sought to determine the role of UVRAG-mediated autophagy in DOX-induced cardiotoxicity. Mouse models of acute or chronic DOX-induced cardiotoxicity were established. UVRAG deficiency exacerbated DOX-induced mortality and cardiotoxicity manifested by increased cytoplasmic vacuolization, enhanced collagen accumulation, elevated serum activities of lactate dehydrogenase and myocardial muscle creatine kinase, higher ROS levels, aggravated apoptosis and more depressed cardiac function. Autophagic flux was impaired in DOX-induced cardiotoxicity. UVRAG deficiency aggravated impaired autophagic flux in DOX-induced cardiotoxicity. Intermittent fasting restored autophagy and ameliorated pathological alterations of DOX-induced cardiotoxicity. Collectively, our data suggest that UVRAG deficiency exacerbates DOX-induced cardiotoxicity, at least in part, through aggravation of DOX-induced impaired autophagic flux. Intermittent fasting, which restores blunted autophagic flux and ameliorates pathology in the mouse models of DOX-induced cardiotoxicity, may be used as a potential preventive or therapeutic approach for DOX cardiotoxicity. PMID:28225086

  12. Doxorubicin treatment inhibits PPARγ and may induce lipotoxicity by mimicking a type 2 diabetes-like condition in rodent models.

    Science.gov (United States)

    Arunachalam, Sankarganesh; Tirupathi Pichiah, P B; Achiraman, Shanmugam

    2013-01-16

    Doxorubicin-treated animals show elevated serum triglyceride and blood glucose levels. Adipocytes play an important role in buffering blood glucose and lipids. A raise in serum lipid level triggers adipogenesis in order to increase the lipid absorption capacity of adipose tissue. Doxorubicin inhibits adipogenesis through the down-regulation of PPARγ, a crucial component of the lipid metabolic pathway which controls the expression of glucose and fatty acid transporters. Doxorubicin-mediated down-regulation of PPARγ inhibits blood glucose and lipid clearance thereby causing hyperglycemia and hyperlipidemia resulting in lipotoxicity, glucotoxicity, inflammation and insulin resistance. Therefore we hypothesize that doxorubicin treatment could mimic a type 2 diabetic condition. Copyright © 2012 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  13. A naive bayes classifier for prediction of multidrug resistance reversal activity on the basis of atom typing.

    Science.gov (United States)

    Sun, Hongmao

    2005-06-16

    Multidrug resistance (MDR), the ability of cancer cells to become simultaneously resistant to different drugs, remains an unsolved challenge in cancer chemotherapy. The use of MDR reversal (MDRR) agents is a promising approach to overcome this problem. For the design and development of such agents, it would be desirable to have a reliable model to estimate the MDRR activity of compounds. Presented here is a naive Bayes classifier to categorize MDRR agents into active and inactive classes, which uses a universal, generic molecular-descriptor system.(1) The naive Bayes classifier was built from a 424 compound training set, selected from 609 druglike compounds in the publicly available "Klopman set". The model correctly predicted MDRR activities for 82.2% of 185 compounds in a testing set. The cumulative probabilities were proven useful for prioritizing the compounds for testing. The impact of attribute dependences on the performance of the classifier was examined. As an unsupervised learner with no tuning parameters, a naive Bayes classifier is capable of providing an objective comparison of the effectiveness of different molecular descriptors. The relative performance of the classifiers constructed from either an atom-type-based molecular descriptor or the long-range functional-class fingerprint descriptors FCFP_6 or FCFP_2 was compared. Employing an atom typing descriptor with the naive Bayes classification, it enables the interpretability of the resulting model, which offers extra information for the rational design of MDRR agents.

  14. Fouling of a spiral-wound reverse osmosis membrane processing swine wastewater: effect of cleaning procedure on fouling resistance.

    Science.gov (United States)

    Camilleri-Rumbau, M S; Masse, L; Dubreuil, J; Mondor, M; Christensen, K V; Norddahl, B

    2016-01-01

    Swine manure is a valuable source of nitrogen, phosphorus and potassium. After solid-liquid separation, the resulting swine wastewater can be concentrated by reverse osmosis (RO) to produce a nitrogen-potassium rich fertilizer. However, swine wastewater has a high fouling potential and an efficient cleaning strategy is required. In this study, a semi-commercial farm scale RO spiral-wound membrane unit was fouled while processing larger volumes of swine wastewater during realistic cyclic operations over a 9-week period. Membrane cleaning was performed daily. Three different cleaning solutions, containing SDS, SDS+EDTA and NaOH were compared. About 99% of the fouling resistance could be removed by rinsing the membrane with water. Flux recoveries (FRs) above 98% were achieved for all the three cleaning solutions after cleaning. No significant differences in FR were found between the cleaning solutions. The NaOH solution thus is a good economical option for cleaning RO spiral-wound membranes fouled with swine wastewater. Soaking the membrane for 3 days in permeate water at the end of each week further improved the FR. Furthermore, a fouling resistance model for predicting the fouling rate, permeate flux decay and cleaning cycle periods based on processing time and swine wastewater conductivity was developed.

  15. Reversal effects of Raloxifene on paclitaxel resistance in 2 MDR breast cancer cells.

    Science.gov (United States)

    Xu, Liang; Lei, Jingyu; Jiang, Donghai; Zhou, Lin; Wang, Shu; Fan, Weimin

    2015-01-01

    Raloxifene hydrochloride (RAL), one of second generation of selective estrogen receptor modulators (SERMs), is usually used in preventing osteoporosis and breast cancer. The present study evaluated whether Raloxifene might sensitize multidrug resistant (MDR) breast cancers to chemotherapies, especially in estrogen receptor negative (ER-) breast cancer. The results showed that RAL could significantly sensitize ER- MDR breast tumors to paclitaxel both in vitro and in vivo. Combination of Raloxifene could significantly enhance paclitaxel-induced cell apoptosis, G2-M arrest as well as inhibition of cell proliferation in MDR tumors. Further studies showed that the combined treatment did not alter P-glycoprotein expression but increased P-gp ATPase activity. These results suggested that raloxifene might be a valuable chemosensitizer agent for breast cancer therapy.

  16. Sensitization of K562 Leukemia Cells to Doxorubicin by the Viscum album Extract.

    Science.gov (United States)

    Srdic-Rajic, Tatjana; Tisma-Miletic, Nevena; Cavic, Milena; Kanjer, Ksenija; Savikin, Katarina; Galun, Danijel; Konic-Ristic, Aleksandra; Zoranovic, Tamara

    2016-03-01

    Toxicity of conventional chemotherapeutics highlights the requirement for complementary or alternative medicines that would reduce side effects and improve their anticancer effectiveness. European mistletoe (Viscum album) has long been used as a complementary and alternative medicine supporting cancer therapy. The aim of this study was to investigate synergistic antitumor action of V. album extract and doxorubicin during co-treatment of chemoresistant chronic myelogenic leukemia K562 cells. Combined treatment of leukemia cells led to inhibitory synergism at sub-apoptotic doxorubicin concentrations and multifold reduction of cytotoxic effects in healthy control cells. Prolonged co-treatment was associated with reduced G2/M accumulation and increased expression of early and late apoptotic markers. Our data indicate that V. album extract increases antileukemic effectiveness of doxorubicin against resistant K562 cells by preventing G2/M arrest and inducing apoptosis. Copyright © 2015 John Wiley & Sons, Ltd.

  17. Pegylated liposomal doxorubicin in ovarian cancer.

    Science.gov (United States)

    Strother, Robert; Matei, Daniela

    2009-06-01

    The encapsulation of doxorubicin in a pegylated liposomal matrix led to a reformulated agent with a different toxicity profile and improved clinical utility. Liposomal doxorubicin is devoid of the cardiac toxicity associated with doxorubicin, but is associated with predictable muco-cutaneous toxicity. The liposomal formulation leads to improved delivery to the target tumor tissue, allowing enhanced uptake by cancer cells. These properties translate into clinical utility in recurrent ovarian cancer as demonstrated by phase II and III trials, this proven clinical efficacy leading to FDA approval in second-line therapy for ovarian cancer. New combinations with cytotoxics, in particular with carboplatin, have demonstrated an acceptable toxicity profile and clinical utility in platinum-sensitive ovarian cancer. A favorable toxicity profile renders liposomal doxorubicin an ideal partner for combination regimens with other cytotoxics, and more recently with biological agents. Such combinations are the subject of ongoing clinical trials.

  18. Enzymatic characterization of human immunodeficiency virus type 1 reverse transcriptase resistant to multiple 2',3'-dideoxynucleoside 5'-triphosphates.

    Science.gov (United States)

    Ueno, T; Shirasaka, T; Mitsuya, H

    1995-10-06

    A set of five mutations (A62V, V75I, F77L, F116Y, and Q151M) in the polymerase domain of reverse transcriptase (RT) of human immunodeficiency virus type 1 (HIV-1), which confers on the virus a reduced sensitivity to multiple therapeutic dideoxynucleosides (ddNs), has been identified. In this study, we defined the biochemical properties of RT with such mutations by using site-directed mutagenesis, overproduction of recombinant RTs, and steady-state kinetic analyses. A single mutation, Q151M, which developed first among the five mutations in patients receiving therapy, most profoundly reduced the sensitivity of RT to multiple ddN 5'-triphosphate (ddNTPs). Addition of other mutations to Q151M further reduced the sensitivity of RT to ddNTPs. RT with the five mutations proved to be resistant by 65-fold to 3'-azido-2',3'-dideoxythymidine 5'-triphosphate (AZTTP), 12-fold to ddCTP, 8.8-fold to ddATP, and 3.3-fold to 2',3'-dideoxyguanosine 5'-triphosphate (ddGTP), compared with wild-type RT (RTwt). Steady-state kinetic studies revealed comparable catalytic efficiency (kcat/Km) of RTs carrying combined mutations as compared with that of RTwt (< 3-fold), although a marked difference was noted in inhibition constants (Ki) (e.g. Ki of a mutant RT carrying the five mutations was 62-fold higher for AZTTP than that of RTwt). Thus, we conclude that the alteration of RT's substrate recognition, caused by these mutations, accounts for the observed multi-ddN resistance of HIV-1. The features of multi-ddNTP-resistant RTs should provide insights into the molecular mechanism of RT discriminating ddNTPs from natural substrates.

  19. High-Resolution Structures of HIV-1 Reverse Transcriptase/TMC278 Complexes: Strategic Flexibility Explains Potency Against Resistance Mutations

    Energy Technology Data Exchange (ETDEWEB)

    Das,K.; Bauman, J.; Clark, Jr., A.; Frenkel, Y.; Lewi, P.; Shatkin, A.; Hughes, S.; Arnold, E.

    2008-01-01

    TMC278 is a diarylpyrimidine (DAPY) nonnucleoside reverse transcriptase inhibitor (NNRTI) that is highly effective in treating wild-type and drug-resistant HIV-1 infections in clinical trials at relatively low doses ({approx}25-75 mg/day). We have determined the structure of wild-type HIV-1 RT complexed with TMC278 at 1.8 Angstroms resolution, using an RT crystal form engineered by systematic RT mutagenesis. This high-resolution structure reveals that the cyanovinyl group of TMC278 is positioned in a hydrophobic tunnel connecting the NNRTI-binding pocket to the nucleic acid-binding cleft. The crystal structures of TMC278 in complexes with the double mutant K103N/Y181C (2.1 Angstroms ) and L100I/K103N HIV-1 RTs (2.9 Angstroms ) demonstrated that TMC278 adapts to bind mutant RTs. In the K103N/Y181C RT/TMC278 structure, loss of the aromatic ring interaction caused by the Y181C mutation is counterbalanced by interactions between the cyanovinyl group of TMC278 and the aromatic side chain of Y183, which is facilitated by an {approx}1.5 Angstroms shift of the conserved Y183MDD motif. In the L100I/K103N RT/TMC278 structure, the binding mode of TMC278 is significantly altered so that the drug conforms to changes in the binding pocket primarily caused by the L100I mutation. The flexible binding pocket acts as a molecular 'shrink wrap' that makes a shape complementary to the optimized TMC278 in wild-type and drug-resistant forms of HIV-1 RT. The crystal structures provide a better understanding of how the flexibility of an inhibitor can compensate for drug-resistance mutations.

  20. Quercetin-glutamic acid conjugate with a non-hydrolysable linker; a novel scaffold for multidrug resistance reversal agents through inhibition of P-glycoprotein.

    Science.gov (United States)

    Kim, Mi Kyoung; Kim, Yunyoung; Choo, Hyunah; Chong, Youhoon

    2017-02-01

    Previously, we have reported remarkable effect of a quercetin-glutamic acid conjugate to reverse multidrug resistance (MDR) of cancer cells to a broad spectrum of anticancer agents through inhibition of P-glycoprotein (Pgp)-mediated drug efflux. Due to the hydrolysable nature, MDR-reversal activity of the quercetin conjugate was attributed to its hydrolysis product, quercetin. However, several lines of evidence demonstrated that the intact quercetin-glutamic acid conjugate has stronger MDR-reversal activity than quercetin. In order to evaluate this hypothesis and to identify a novel scaffold for MDR-reversal agents, we prepared quercetin conjugates with a glutamic acid attached at the 7-O position via a non-hydrolysable linker. Pgp inhibition assay, Pgp ATPase assay, and MDR-reversal activity assay were performed, and the non-hydrolysable quercetin conjugates showed significantly higher activities compared with those of quercetin. Unfortunately, the quercetin conjugates were not as effective as verapamil in Pgp-inhibition and thereby reversing MDR, but it is worth to note that the structurally modified quercetin conjugates with a non-cleavable linker showed significantly improved MDR-reversal activity compared with quercetin. Taken together, the quercetin conjugates with appropriate structural modifications were shown to have a potential to serve as a scaffold for the design of novel MDR-reversal agents. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Guggulsterone of Commiphora mukul resin reverses drug resistance in imatinib-resistant leukemic cells by inhibiting cyclooxygenase-2 and P-glycoprotein.

    Science.gov (United States)

    Xu, Hong-Bin; Xu, Lu-Zhong; Mao, Xia-Ping; Fu, Jun

    2014-06-15

    The purpose of this study was to investigate the effects of guggulsterone on cyclooxygenase-2 and P-glycoprotein mediated drug resistance in imatinib-resistant K562 cells (K562/IMA). MTT cytotoxicity assay, flow cytometry, western blot analysis, and ELISA were performed to investigate the anti-proliferative effect, the reversal action of drug resistance, and the inhibitory effect on cyclooxygenase-2, P-glycoprotein, BCR/ABL kinase, and PGE2 release in K562/IMA cells by guggulsterone. The results showed that co-administration of guggulsterone resulted in a significant increase in chemo-sensitivity of K562/IMA cells to imatinib, compared with imatinib treatment alone. Rhodamine123 accumulation in K562/IMA cells was significantly enhanced after incubation with guggulsterone (60, 120 μM), compared with untreated K562/IMA cells (p<0.05). When imatinib (1 μM) was combined with guggulsterone (60, 120 μM), the mean apoptotic population of K562/IMA cells was 15.47% and 24.91%. It was increased by 3.82 and 6.79 times, compared with imatinib (1 μM) treatment alone. Furthermore, guggulsterone had significantly inhibitory effects on the levels of cyclooxygenase-2, P-glycoprotein and prostaglandin E2. However, guggulsterone had little inhibitory effect on the activity of BCR/ABL kinase. The present study indicates guggulsterone induces apoptosis by inhibiting cyclooxygenase-2 and down-regulating P-glycoprotein expression in K562/IMA cells. Copyright © 2014 Elsevier GmbH. All rights reserved.

  2. SIRT1 Suppresses Doxorubicin-Induced Cardiotoxicity by Regulating the Oxidative Stress and p38MAPK Pathways

    Directory of Open Access Journals (Sweden)

    Yang Ruan

    2015-02-01

    Full Text Available Background: SIRT1, which belongs to the Sirtuin family of NAD-dependent enzymes, plays diverse roles in aging, metabolism, and disease biology. It could regulate cell survival and has been shown to be a protective factor in heart function. Hence, we verified the mechanism by which SIRT1 regulates doxorubicin induced cardiomyocyte injury in vivo and in vitro. Methods: We analyzed SIRT1 expression in doxorubicin-induced neonatal rat cardiomyocyte injury model and adult mouse heart failure model. SIRT1 was over-expressed in cultured neonatal rat cardiomyocyte by adenovirus mediated gene transfer. SIRT1 agonist resveratrol was used to treat the doxorubicin-induced heart failure mouse model. Echocardiography, reactive oxygen species (ROS production, TUNEL, qRT-PCR, and Western blotting were performed to analyze cell survival, oxidative stress, and inflammatory signal pathways in cardiomyocytes. Results: SIRT1 expression was down-regulated in doxorubicin induced cardiomocyte injury, accompanied by elevated oxidative stress and cell apoptosis. SIRT1 over-expression reduced doxorubicin induced cardiomyocyte apoptosis with the attenuated ROS production. SIRT1 also reduced cell apoptosis by inhibition of p38MAPK phosphorylation and caspase-3 activation. The SIRT1 agonist resveratrol was able to prevent doxorubicin-induced heart function loss. Moreover, the SIRT1 inhibitor niacinamide could reverse SIRT1's protective effect in cultured neonatal rat cardiomyocytes. Conclusions: These results support the role of SIRT1 as an important regulator of cardiomyocyte apoptosis during doxorubicin-induced heart injury, which may represent a potential therapeutic target for doxorubicin-induced cardiomyopathy.

  3. S-diclofenac protects against doxorubicin-induced cardiomyopathy in mice via ameliorating cardiac gap junction remodeling.

    Directory of Open Access Journals (Sweden)

    Huili Zhang

    Full Text Available Hydrogen sulfide (H(2S, as a novel gaseous mediator, plays important roles in mammalian cardiovascular tissues. In the present study, we investigated the cardioprotective effect of S-diclofenac (2-[(2,6-dichlorophenylamino] benzeneacetic acid 4-(3H-1,2,dithiol-3-thione-5-ylphenyl ester, a novel H(2S-releasing derivative of diclofenac, in a murine model of doxorubicin-induced cardiomyopathy. After a single dose injection of doxorubicin (15 mg/kg, i.p., male C57BL/6J mice were given daily treatment of S-diclofenac (25 and 50 µmol/kg, i.p., diclofenac (25 and 50 µmol/kg, i.p., NaHS (50 µmol/kg, i.p., or same volume of vehicle. The cardioprotective effect of S-diclofenac was observed after 14 days. It showed that S-diclofenac, but not diclofenac, dose-dependently inhibited the doxorubicin-induced downregulation of cardiac gap junction proteins (connexin 43 and connexin 45 and thus reversed the remodeling of gap junctions in hearts. It also dose-dependently suppressed doxorubicin-induced activation of JNK in hearts. Furthermore, S-diclofenac produced a dose-dependent anti-inflammatory and anti-oxidative effect in this model. As a result, S-diclofenac significantly attenuated doxorubicin-related cardiac injury and cardiac dysfunction, and improved the survival rate of mice with doxorubicin-induced cardiomyopathy. These effects of S-diclofenac were mimicked in large part by NaHS. Therefore, we propose that H(2S released from S-diclofenac in vivo contributes to the protective effect in doxorubicin-induced cardiomyopathy. These data also provide evidence for a critical role of H(2S in the pathogenesis of doxorubicin-induced cardiomyopathy.

  4. Resistance to gemcitabine in the pancreatic cancer cell line KLM1-R reversed by metformin action.

    Science.gov (United States)

    Baron, Byron; Wang, Yufeng; Maehara, Shin-Ichiro; Maehara, Yoshihiko; Kuramitsu, Yasuhiro; Nakamura, Kazuyuki

    2015-04-01

    The pancreatic cancer cell line KLM1 can gain chemoresistance following gemcitabine (GEM) treatment. Metformin was found to be a useful sensitising agent towards GEM treatment following gain of chemoresistance. The proliferation of GEM-sensitive and -resistant cells was investigated over a range of metformin concentrations from 0.005 to 5 mM. The intra- and extra-cellular energetic profiles of these two cell types under metformin exposure were investigated through adenosine triphosphate (ATP) and L-lactate assays. There was an unexpected decrease in intracellular L-lactate following gain of chemoresistance, despite observable medium acidification. At the biochemical level, a marked effect on phosphorylated proteins upstream of Akt, along the mTOR pathway, was observed at 6 h. These changes followed a time-dependent pattern linked closely to the changes in the energetic profile. Together, these results indicate that metformin indirectly blocks protein phosphorylation, including that of heat shock protein 27 (HSP27). Copyright© 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  5. Nanostructured wear resistant coating for reversible cultivator shovels: An experimental investigation

    Energy Technology Data Exchange (ETDEWEB)

    Dave, V., E-mail: vdaditya1000@gmail.com [Department of Electrical Engineering,College of Technology and Engineerin, MPUAT Udaipur, 313001,India (India); Rao, G. P., E-mail: ragrao38@gmail.com; Tiwari, G. S., E-mail: tiwarigsin@yahoo.com [Department of Farm Machinery and Power Engineering, MPUAT Udaipur, 313001,India (India); Sanger, A., E-mail: amitsangeriitr@gmail.com; Kumar, A., E-mail: 01ashraj@gmail.com; Chandra, R., E-mail: ramesfic@gmail.com [Institute Instrumentation Centre, Indian Institute of Technology Roorkee, Roorkee 247667 (India)

    2016-04-13

    Cultivator, one of the agriculture farm tool, extensively suffers from the wear problem. In this paper, we report nanostructured chromium nitrite (CrN) coating for the cultivator shovels to mitigate wear problem. The (CrN) coating was developed using DC magnetron sputtering technique at 200 °C. The structural, morphological, hydrophobic and wear properties were investigated using X-ray diffractometer, scanning electron microscope, contact angle goniometer and custom designed soil bin assembly. The XRD reveals that the deposited coating was polycrystalline in nature with cubic structure. Also, The deposited coating was found to be anti wear resistant as well as hydrophobic in nature. The gravimetric wear for the coating developed at 200 °C coated was found out to be 8.15 gm and for non coated it was 14.48 gm tested for 100 hrs. The roughness of the coating plays an important role in determining the hydrophobicity of the coated film. Roughness and contact angle measured for 200 °C coated shovel was found out to be 11.17 nm and 105 ° respectively.

  6. Pegylated liposomal doxorubicin in ovarian cancer

    Directory of Open Access Journals (Sweden)

    Robert Strother

    2009-08-01

    Full Text Available Robert Strother1,2, Daniela Matei1–51Department of Medicine, 2Indiana University Melvin and Bren Simon Cancer Center, 3Department of Obstetrics and Gynecology, 4Department of Biochemistry and Molecular Biology, 5VA Roudebush Hospital Indiana University School of Medicine, 535 Barnhill Drive, Indianapolis, IN, 46202Abstract: The encapsulation of doxorubicin in a pegylated liposomal matrix led to a reformulated agent with a different toxicity profile and improved clinical utility. Liposomal doxorubicin is devoid of the cardiac toxicity associated with doxorubicin, but is associated with predictable muco-cutaneous toxicity. The liposomal formulation leads to improved delivery to the target tumor tissue, allowing enhanced uptake by cancer cells. These properties translate into clinical utility in recurrent ovarian cancer as demonstrated by phase II and III trials, this proven clinical efficacy leading to FDA approval in second-line therapy for ovarian cancer. New combinations with cytotoxics, in particular with carboplatin, have demonstrated an acceptable toxicity profile and clinical utility in platinum-sensitive ovarian cancer. A favorable toxicity profile renders liposomal doxorubicin an ideal partner for combination regimens with other cytotoxics, and more recently with biological agents. Such combinations are the subject of ongoing clinical trials.Keywords: ovarian cancer, doxorubicin, liposomes, pegylated liposomal doxorubicin

  7. Src Inhibition Can Synergize with Gemcitabine and Reverse Resistance in Triple Negative Breast Cancer Cells via the AKT/c-Jun Pathway.

    Directory of Open Access Journals (Sweden)

    Zhen-Hua Wu

    Full Text Available Gemcitabine-based chemotherapy remains one of the standards in management of metastatic breast cancer. However, intrinsic and acquired resistance to gemcitabine inevitably occurs. The aims of this study were to assess the efficacy of the combination of src inhibition and gemcitabine in gemcitabine-resistant breast cancer cells.By using colony formation, sphere forming, flow cytometry, cell counting kit-8 and transwell assays, 231/GEM-res (gemcitabine-resistant cell line, which was 10 times more resistant, was shown to have elevated drug tolerance, enhanced proliferative and self-renewal abilities, compared with its parental cells. Inhibition of src by both saracatinib (AZD0530 and siRNA could partially reverse gemcitabine resistance and attenuate resistance-associated anti-apoptosis, migration and stem cell capacities. In addition, the combination of src inhibition and gemcitabine had synergistic antitumor effects. Western blot analysis revealed up-regulation of pro-apoptotic protein BAX, along with the down-regulation of anti-apoptotic proteins (BCL-XL, Survivin, migration associated proteins (p-FAK, MMP-3 and cancer stem cell (CSC markers (CD44, Oct-4, which was probably mediated by AKT/c-Jun pathway.In highly gemcitabine-resistant 231 cells, src inhibition can synergize with gemcitabine, reverse drug resistance, inhibit tumor growth/metastasis/stemness of cancer stem cells, possibly via the AKT/c-Jun pathway.

  8. Structural Insights into HIV Reverse Transcriptase Mutations Q151M and Q151M Complex That Confer Multinucleoside Drug Resistance

    Energy Technology Data Exchange (ETDEWEB)

    Das, Kalyan; Martinez, Sergio E.; Arnold, Eddy

    2017-04-10

    HIV-1 reverse transcriptase (RT) is targeted by multiple drugs. RT mutations that confer resistance to nucleoside RT inhibitors (NRTIs) emerge during clinical use. Q151M and four associated mutations, A62V, V75I, F77L, and F116Y, were detected in patients failing therapies with dideoxynucleosides (didanosine [ddI], zalcitabine [ddC]) and/or zidovudine (AZT). The cluster of the five mutations is referred to as the Q151M complex (Q151Mc), and an RT or virus containing Q151Mc exhibits resistance to multiple NRTIs. To understand the structural basis for Q151M and Q151Mc resistance, we systematically determined the crystal structures of the wild-type RT/double-stranded DNA (dsDNA)/dATP (complex I), wild-type RT/dsDNA/ddATP (complex II), Q151M RT/dsDNA/dATP (complex III), Q151Mc RT/dsDNA/dATP (complex IV), and Q151Mc RT/dsDNA/ddATP (complex V) ternary complexes. The structures revealed that the deoxyribose rings of dATP and ddATP have 3'-endo and 3'-exo conformations, respectively. The single mutation Q151M introduces conformational perturbation at the deoxynucleoside triphosphate (dNTP)-binding pocket, and the mutated pocket may exist in multiple conformations. The compensatory set of mutations in Q151Mc, particularly F116Y, restricts the side chain flexibility of M151 and helps restore the DNA polymerization efficiency of the enzyme. The altered dNTP-binding pocket in Q151Mc RT has the Q151-R72 hydrogen bond removed and has a switched conformation for the key conserved residue R72 compared to that in wild-type RT. On the basis of a modeled structure of hepatitis B virus (HBV) polymerase, the residues R72, Y116, M151, and M184 in Q151Mc HIV-1 RT are conserved in wild-type HBV polymerase as residues R41, Y89, M171, and M204, respectively; functionally, both Q151Mc HIV-1 and wild-type HBV are resistant to dideoxynucleoside analogs.

  9. Investigation of elemene-induced reversal of tamoxifen resistance in MCF-7 cells through oestrogen receptor α (ERα) re-expression.

    Science.gov (United States)

    Zhang, Bin; Zhang, Xia; Tang, Bo; Zheng, Peishi; Zhang, Yang

    2012-11-01

    Endocrine therapy is an important therapeutic approach for the treatment of oestrogen receptor (ER)-positive breast cancer. However, a number of these endocrine therapies can fail when the tumour loses its ER expression during treatment. To date, few studies have explored the potential clinical significance of traditional Chinese medicine in inducing the reversal of resistance to endocrine therapy in breast cancers. We used the ERα-negative MCF7 breast cancer cell line to create a tamoxifen (TAM)-resistant cell line, MCF7/TAM cells. After treating MCF7/TAM cells with ELE to induce the re-expression of ERα, we investigated the role and molecular mechanisms by which elemene (ELE) promotes the reversal of resistance to endocrine therapy. We discovered that treatment with 10 μg/ml ELE restored the sensitivity of MCF7/TAM cells to TAM. RT-PCR analysis revealed that ELE treatment upregulated ERα mRNA levels in MCF7/TAM cells, and immunohistochemistry confirmed the upregulation of ERα expression. Western blot analysis revealed that ELE treatment decreased the protein expression levels of Ras, MEK1/2 and p-ERK1/2 in MCF7/TAM cells. The loss of ERα expression was the primary reason for TAM resistance in MCF7 cells. The ELE-induced reversal of TAM resistance was mediated by the upregulation of ERα mRNA and the re-expression of ERα through the MAPK pathway.

  10. Cryptotanshinone Reverses Cisplatin Resistance of Human Lung Carcinoma A549 Cells through Down-Regulating Nrf2 Pathway

    Directory of Open Access Journals (Sweden)

    Chen Xia

    2015-09-01

    Full Text Available Background/Aims: To explore whether Nrf2 was associated with drug-resistance in cisplatin resistant A549 (A549/DDP cells, and if cryptotanshinone (CTS, one of the bioactive compounds isolated from the roots of Salvia miltiorrhiza Bunge (Danshen, could enhance the sensitivity in A549/DDP cells towards cisplatin. Methods: A549 and A549/DDP cells were subjected to various treatments, and then Sulforhodamine B (SRB assay, flow cytometry analysis and western immunoblotting analysis were applied to determine IC50, apoptotic status and expressions of Nrf2 and its downstream genes. Results: The endogenous expression levels of Nrf2 as well as its target genes including GCLC, GCLM, HO-1, NQO1 and MRP1 were much higher in A549/DDP cells than those of A549 cells and the susceptibility of A549/DDP cells to cisplatin was partially restored by silencing Nrf2. The combination of CTS and cisplatin led to cell death and apoptosis through sensitizing A549/DDP cells towards cisplatin compared with cisplatin mono-treatment, however, this reversal role could be abolished by Nrf2 knockdown. Specifically, CTS obviously diminished Nrf2 expression, thus contributing to the decrease of Nrf2-target genes expression levels. Meanwhile, we also discovered that CTS triggered several other signals involving in chemoresistance such as MAPKs, Akt and STAT3 pathway. Conclusion: Our data indicated CTS may be developed as a potential sensitizer cooperating with anticancer drugs to combat chemoresistant carcinoma through the inhibition of the Nrf2 pathway.

  11. Lamellarin O, a Pyrrole Alkaloid from an Australian Marine Sponge, Ianthella sp., Reverses BCRP Mediated Drug Resistance in Cancer Cells

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    Xiao-Cong Huang

    2014-06-01

    Full Text Available ATP binding cassette (ABC transporters, such as P-gp, BCRP and MRP1, can increase efflux of clinical chemotherapeutic agents and lead to multi-drug resistance (MDR in cancer cells. While the discovery and development of clinically useful inhibitors has proved elusive to date, this molecular target nevertheless remains a promising strategy for addressing and potentially overcoming MDR. In a search for new classes of inhibitor, we used fluorescent accumulation and efflux assays supported by cell flow cytometry and MDR reversal assays, against a panel of sensitive and MDR human cancer cell lines, to evaluate the marine sponge co-metabolites 1–12 as inhibitors of P-gp, BCRP or MRP1 initiated MDR. These studies identified and characterized lamellarin O (11 as a selective inhibitor of BCRP mediated drug efflux. A structure–activity relationship analysis inclusive of the natural products 1–12 and the synthetic analogues 13–19, supported by in silico docking studies, revealed key structural requirements for the lamellarin O (11 BCRP inhibitory pharmacophore.

  12. Resistive wall instabilities and tearing mode dynamics in the EXTRAP T2R thin shell reversed-field pinch

    Science.gov (United States)

    Malmberg, J.-A.; Brunsell, P. R.

    2002-01-01

    Observations of resistive wall instabilities and tearing mode dynamics in the EXTRAP T2R thin shell (τw=6 ms) reversed field pinch are described. A nonresonant mode (m=1,n=-10) with the same handedness as the internal field grows nearly exponentially with an average growth time of about 2.6 ms (less than 1/2 of the shell time) consistent with linear stability theory. The externally nonresonant unstable modes (m=1,n>0), predicted by linear stability theory, are observed to have only low amplitudes (in the normal low-Θ operation mode of the device). The radial field of the dominant internally resonant tearing modes (m=1,n=-15 to n=-12) remain low due to spontaneous fast mode rotation, corresponding to angular phase velocities up to 280 krad/s. Phase aligned mode structures are observed to rotate toroidally with an average angular velocity of 40 krad/s, in the opposite direction of the plasma current. Toward the end of the discharge, the radial field of the internally resonant modes grows as the modes slow down and become wall-locked, in agreement with nonlinear computations. Fast rotation of the internally resonant modes has been observed only recently and is attributed to a change of the front-end system (vacuum vessel, shell, and TF coil) of the device.

  13. Mutagenesis of the Glu-89 residue in human immunodeficiency virus type 1 (HIV-1) and HIV-2 reverse transcriptases: effects on nucleoside analog resistance.

    Science.gov (United States)

    Song, Q; Yang, G; Goff, S P; Prasad, V R

    1992-12-01

    A Glu-89-->Gly alteration in the human immunodeficiency virus type 1 reverse transcriptase (RT) was previously shown to result in resistance to several dideoxynucleoside analogs and to phosphonoformic acid (PFA; foscarnet). This residue was altered to Ala, Val, Ser, Thr, Gln, Asp, Asn, or Lys, and the ddGTP and PFA sensitivities of the mutant RTs were measured. Replacements with Ala, Gly, Val, and Thr led to resistance to inhibition by ddGTP, while mutants with amino acid Ser, Gln, Asn, Asp, or Lys displayed only moderate or no resistance. A similar result was obtained with inhibition by PFA, except that the Asp-89 mutant also displayed resistance. Furthermore, the introduction of Glu-89-->Gly alteration into the RT of human immunodeficiency virus type 2 likewise rendered it resistant to both ddGTP and PFA.

  14. Magnetic nanoparticles sensitize MCF-7 breast cancer cells to doxorubicin-induced apoptosis

    Directory of Open Access Journals (Sweden)

    Aljarrah Khaled

    2012-04-01

    Full Text Available Abstract Background Resistance of breast cancer cells to the available chemotherapeutics is a major obstacle to successful treatment. Recent studies have shown that magnetic nanoparticles might have significant application in different medical fields including cancer treatment. The goal of this study is to verify the ability of magnetic nanoparticles to sensitize cancer cells to the clinically available chemotherapy. Methods The role of iron oxide nanoparticles, static magnetic field, or a combination in the enhancement of the apoptotic potential of doxorubicin against the resistant breast cancer cells, MCF-7 was evaluated using the MTT assay and the propidium iodide method. Results In the present study, results revealed that pre-incubation of MCF-7 cells with iron oxide nanoparticles before the addition of doxorubicin did not enhance doxorubicin-induced growth inhibition. Pre-incubation of MCF-7 cells with iron oxide nanoparticles followed by a static magnetic field exposure significantly (P  Conclusions These results might point to the importance of combining magnetic nanoparticles with a static magnetic field in treatment of doxorubicin-refractory breast cancer cells.

  15. Magnetic nanoparticles sensitize MCF-7 breast cancer cells to doxorubicin-induced apoptosis.

    Science.gov (United States)

    Aljarrah, Khaled; Mhaidat, Nizar M; Al-Akhras, M-Ali H; Aldaher, Ahmad N; Albiss, Ba; Aledealat, Khaled; Alsheyab, Fawzi M

    2012-04-25

    Resistance of breast cancer cells to the available chemotherapeutics is a major obstacle to successful treatment. Recent studies have shown that magnetic nanoparticles might have significant application in different medical fields including cancer treatment. The goal of this study is to verify the ability of magnetic nanoparticles to sensitize cancer cells to the clinically available chemotherapy. The role of iron oxide nanoparticles, static magnetic field, or a combination in the enhancement of the apoptotic potential of doxorubicin against the resistant breast cancer cells, MCF-7 was evaluated using the MTT assay and the propidium iodide method. In the present study, results revealed that pre-incubation of MCF-7 cells with iron oxide nanoparticles before the addition of doxorubicin did not enhance doxorubicin-induced growth inhibition. Pre-incubation of MCF-7 cells with iron oxide nanoparticles followed by a static magnetic field exposure significantly (P magnetic field was dose-dependent where the highest cytotoxicity was seen at 1 tesla. Further experiments revealed that the anti-proliferative effect of this treatment procedure is due to induction of apoptotic cell death. These results might point to the importance of combining magnetic nanoparticles with a static magnetic field in treatment of doxorubicin-refractory breast cancer cells.

  16. Recovery of symptomatic extravasation of liposomal doxorubicin after dexrazoxane treatment.

    NARCIS (Netherlands)

    Vos, F.Y.F.L. de; Lesterhuis, W.J.; Bruggemann, R.J.M.; Graaf, W.T.A. van der

    2012-01-01

    A patient with metastatic ovarian cancer was treated with liposomal doxorubicin and carboplatin. She had an extravasation during liposomal doxorubicin infusion. Initially, she was treated conservatively with cold compresses and topical treatment. However, because of worsening of symptoms, she

  17. Synergistic anti-tumor efficacy of doxorubicin and flavopiridol in an in vivo hepatocellular carcinoma model.

    Science.gov (United States)

    Kwak, Min-Sun; Yu, Su Jong; Yoon, Jung-Hwan; Lee, Sung-Hee; Lee, Soo-Mi; Lee, Jeong-Hoon; Kim, Yoon Jun; Lee, Hyo-Suk; Kim, Chung Yong

    2015-11-01

    A previous study showed that flavopiridol increased doxorubicin sensitivity in hypoxic hepatocellular carcinoma (HCC) cells by increasing apoptosis through suppressing hypoxia-inducible N-myc downstream-regulated gene-1 (NDRG1) expression. However, this has not been investigated in an in vivo HCC model. Therefore, we aimed to elucidate whether the combination of doxorubicin and flavopiridol has a synergistic anti-tumor effect in an in vivo HCC model. An HCC mouse model was established by implanting C3H/He mouse with MH134 cells. Then, doxorubicin with or without flavopiridol was injected. The anti-tumor efficacy was assessed by evaluating tumor volumes, and the underlying mechanism was investigated by quantifying apoptotic cells, the Ki-67 proliferation index, and microvessel densities (MVDs). Immunohistochemistry of NDRG1 was performed to determine the underlying mechanism. Tumor growth was significantly suppressed in the doxorubicin + flavopiridol combination group compared to the other three groups. The percentage of apoptotic cells was significantly higher, and Ki-67-positive proliferating cells were significantly lower in the combination group compared to the other groups; however, MVDs were not significantly different across the groups. Increased apoptosis by flavopiridol occurred by suppressing hypoxia-inducible NDRG1 expression. These results show that a combination of doxorubicin and flavopiridol has a synergistic anti-tumor effect in an in vivo HCC model. This synergistic effect of combination therapy was attributed to increased apoptosis and decreased proliferation of tumor cells rather than decreased angiogenesis. These findings suggest that flavopiridol might be an effective adjuvant therapy to doxorubicin-resistant HCC cells by inducing apoptosis through suppression of NDRG1 expression.

  18. Celastraceae sesquiterpenes as a new class of modulators that bind specifically to human P-glycoprotein and reverse cellular multidrug resistance.

    Science.gov (United States)

    Muñoz-Martínez, Francisco; Lu, Peihua; Cortés-Selva, Fernando; Pérez-Victoria, José María; Jiménez, Ignacio A; Ravelo, Angel G; Sharom, Frances J; Gamarro, Francisco; Castanys, Santiago

    2004-10-01

    Overexpression of ABCB1 (MDR1) P-glycoprotein, a multidrug efflux pump, is one mechanism by which tumor cells may develop multidrug resistance (MDR), preventing the successful chemotherapeutic treatment of cancer. Sesquiterpenes from Celastraceae family are natural compounds shown previously to reverse MDR in several human cancer cell lines and Leishmania strains. However, their molecular mechanism of reversion has not been characterized. In the present work, we have studied the ability of 28 dihydro-beta-agarofuran sesquiterpenes to reverse the P-glycoprotein-dependent MDR phenotype and elucidated their molecular mechanism of action. Cytotoxicity assays using human MDR1-transfected NIH-3T3 cells allowed us to select the most potent sesquiterpenes reversing the in vitro resistance to daunomycin and vinblastine. Flow cytometry experiments showed that the above active compounds specifically inhibited drug transport activity of P-glycoprotein in a saturable, concentration-dependent manner (K(i) down to 0.24 +/- 0.01 micromol/L) but not that of ABCC1 (multidrug resistance protein 1; MRP1), ABCC2 (MRP2), and ABCG2 (breast cancer resistance protein; BCRP) transporters. Moreover, sesquiterpenes inhibited at submicromolar concentrations the P-glycoprotein-mediated transport of [(3)H]colchicine and tetramethylrosamine in plasma membrane from CH(R)B30 cells and P-glycoprotein-enriched proteoliposomes, supporting that P-glycoprotein is their molecular target. Photoaffinity labeling in plasma membrane and fluorescence spectroscopy experiments with purified protein suggested that sesquiterpenes interact with transmembrane domains of P-glycoprotein. Finally, sesquiterpenes modulated P-glycoprotein ATPase-activity in a biphasic, concentration-dependent manner: they stimulated at very low concentrations but inhibited ATPase activity as noncompetitive inhibitors at higher concentrations. Sesquiterpenes from Celastraceae are promising P-glycoprotein modulators with potential

  19. Mechanism of the reversal effect of mifepristone on drug resistance of the human cervical cancer cell line HeLa/MMC.

    Science.gov (United States)

    Chen, H; Duan, J; Zuo, F

    2014-02-27

    We examined the ability of mifepristone to reverse the in vitro drug resistance of human cervical cancer cells resistant to mitomycin-C (HeLa/MMC) cells and investigated the mechanism of this effect. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed to detect the drug resistance of HeLa/MMC cells and the reversed drug resistance in vitro. Expression levels of B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), and glucosylceramide synthase (GCS) were measured in HeLa and HeLa/MMC cells. The resistance index of HeLa/MMC cells on MMC was reduced from 5.02 to 1.46 after 10 mg/mL mifepristone exposure. A combination of mifepristone upregulated the Bax/Bcl-2 protein expression ratio and apoptosis in HeLa/MMC cells. GCS expression was significantly higher in HeLa/MMC cells than in HeLa cells (P MMC cells to MMC in vitro; the overexpression of the GCS gene and the increased expression of apoptosis-related protein Bcl-2 may play important roles in the formation of multidrug resistance in cervical cancer.

  20. Knockdown of HOXA10 reverses the multidrug resistance of human chronic mylogenous leukemia K562/ADM cells by downregulating P-gp and MRP-1.

    Science.gov (United States)

    Yi, Ying-Jie; Jia, Xiu-Hong; Wang, Jian-Yong; Li, You-Jie; Wang, Hong; Xie, Shu-Yang

    2016-05-01

    Multidrug resistance (MDR) of leukemia cells is a major obstacle in chemotherapeutic treatment. The high expression and constitutive activation of P-glycoprotein (P-gp) and multidrug resistance protein-1 (MRP-1) have been reported to play a vital role in enhancing cell resistance to anticancer drugs in many tumors. The present study aimed to investigate the reversal of MDR by silencing homeobox A10 (HOXA10) in adriamycin (ADR)-resistant human chronic myelogenous leukemia (CML) K562/ADM cells by modulating the expression of P-gp and MRP-1. K562/ADM cells were stably transfected with HOXA10-targeted short hairpin RNA (shRNA). The results of reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis showed that the mRNA and protein expression of HOXA10 was markedly suppressed following transfection with a shRNA-containing vector. The sensitivity of the K562/ADM cells to ADR was enhanced by the silencing of HOXA10, due to the increased intracellular accumulation of ADR. The accumulation of ADR induced by the silencing of HOXA10 may be due to the downregulation of P-gp and MRP-1. Western blot analysis revealed that downregulating HOXA10 inhibited the protein expression of P-gp and MRP-1. Taken together, these results suggest that knockdown of HOXA10 combats resistance and that HOXA10 is a potential target for resistant human CML.

  1. Effects of pluronic and doxorubicin on drug uptake, cellular metabolism, apoptosis and tumor inhibition in animal models of MDR cancers.

    Science.gov (United States)

    Batrakova, Elena V; Li, Shu; Brynskikh, Anna M; Sharma, Amit K; Li, Yili; Boska, Michael; Gong, Nan; Mosley, R Lee; Alakhov, Valery Yu; Gendelman, Howard E; Kabanov, Alexander V

    2010-05-10

    Cancer chemotherapy is believed to be impeded by multidrug resistance (MDR). Pluronic (triblock copolymers of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO), PEO-b-PPO-b-PEO) were previously shown to sensitize MDR tumors to antineoplastic agents. This study uses animal models of Lewis lung carcinoma (3LL-M27) and T-lymphocytic leukemia (P388/ADR and P388) derived solid tumors to delineate mechanisms of sensitization of MDR tumors by Pluronic P85 (P85) in vivo. First, non-invasive single photon emission computed tomography (SPECT) and tumor tissue radioactivity sampling demonstrate that intravenous co-administration of P85 with a Pgp substrate, 99Tc-sestamibi, greatly increases the tumor uptake of this substrate in the MDR tumors. Second, 31P magnetic resonance spectroscopy (31P-MRS) in live animals and tumor tissue sampling for ATP suggest that P85 and doxorubicin (Dox) formulations induce pronounced ATP depletion in MDR tumors. Third, these formulations are shown to increase tumor apoptosis in vivo by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay and reverse transcription polymerase chain reaction (RT-PCR) for caspases 8 and 9. Altogether, formulation of Dox with P85 results in increased inhibition of the growth solid tumors in mice and represents novel and promising strategy for therapy of drug resistant cancers. Published by Elsevier B.V.

  2. Exploration of Electrochemical Intermediates of the Anticancer Drug Doxorubicin Hydrochloride Using Cyclic Voltammetry and Simulation Studies with an Evaluation for Its Interaction with DNA

    Directory of Open Access Journals (Sweden)

    Partha Sarathi Guin

    2014-01-01

    Full Text Available Electrochemical behavior of the anticancer drug doxorubicin hydrochloride was studied using cyclic voltammetry in aqueous medium using Hepes buffer (pH~7.4. At this pH, doxorubicin hydrochloride undergoes a reversible two-electron reduction with E1/2 value −665±5 mV (versus Ag/AgCl, saturated KCl. Depending on scan rates, processes were either quasireversible (at low scan rates or near perfect reversible (at high scan rates. This difference in behavior of doxorubicin hydrochloride with scan rate studied over the same potential range speaks of differences in electron transfer processes in doxorubicin hydrochloride. Attempt was made to identify and understand the species involved using simulation. The information obtained was used to study the interaction of doxorubicin hydrochloride with calf thymus DNA. Cathodic peak current gradually decreased as more calf thymus DNA was added. The decrease in cathodic peak current was used to estimate the interaction of the drug with calf thymus DNA. Nonlinear curve fit analysis was applied to evaluate the intrinsic binding constant and site size of interaction that was compared with previous results on doxorubicin hydrochloride-DNA interaction monitored by cyclic voltammetry or spectroscopic techniques.

  3. Verteporfin can Reverse the Paclitaxel Resistance Induced by YAP Over-Expression in HCT-8/T Cells without Photoactivation through Inhibiting YAP Expression

    Directory of Open Access Journals (Sweden)

    Wang Pan

    2016-07-01

    Full Text Available Background/Aims: Paclitaxel (PTX is one of the most effective anti-cancer drugs. However, multiple drug resistance is still the main factor that hinders the effective treatment of cancer with PTX. Several factors including YAP over-expression can cause PTX resistance. In this study, we aimed to verify the role YAP plays in PTX resistance, explore the reversal of PTX resistance by verteporfin (VP and investigate the effect of combination therapy of PTX and VP on the PTX resistant colon cancer cells (HCT-8/T. Methods: To study the relationship between YAP and PTX resistance, a stable YAP-over-expression or YAP silencing cell line was generated by transfected with YAP-plasmids or siYAP-RNA. WST-1 assay was performed to detect the cytotoxicity of PTX on HCT-8 and HCT-8/T cells. Clone formation assay and Transwell assay was preformed to determine the cell proliferation and invasion ability respectively. Immunofluorescence and Western blot analysis was performed for protein detection. Results: YAP was stronger expressed in HCT-8/T than in HCT-8, and PTX resistance was positively correlated with the level of YAP expression. VP, a strongly YAP inhibitor, could reduce the PTX resistance on HCT-8/T cells without light activation by inhibiting YAP. Beside, VP and PTX combination therapy showed synergism on inhibition of YAP and cytotoxicity to HCT-8/T. Moreover, verteporfin and PTX combination therapy affect the invasion and colony formation ability and induce apoptosis of HCT-8/T cells. Conclusions: VP can reverse the PTX resistance induced by YAP over-expression in HCT-8/T cells without photoactivation through inhibiting YAP expression.

  4. Mutagenesis of the Glu-89 residue in human immunodeficiency virus type 1 (HIV-1) and HIV-2 reverse transcriptases: effects on nucleoside analog resistance.

    OpenAIRE

    Song, Q; Yang, G; Goff, S P; Prasad, V R

    1992-01-01

    A Glu-89-->Gly alteration in the human immunodeficiency virus type 1 reverse transcriptase (RT) was previously shown to result in resistance to several dideoxynucleoside analogs and to phosphonoformic acid (PFA; foscarnet). This residue was altered to Ala, Val, Ser, Thr, Gln, Asp, Asn, or Lys, and the ddGTP and PFA sensitivities of the mutant RTs were measured. Replacements with Ala, Gly, Val, and Thr led to resistance to inhibition by ddGTP, while mutants with amino acid Ser, Gln, Asn, Asp, ...

  5. Emodin: One Main Ingredient of Shufeng Jiedu Capsule Reverses Chemoresistance of Lung Cancer Cells Through Inhibition of EMT.

    Science.gov (United States)

    Ying, Yuan; Qingwu, Liao; Mingming, Xue; Zhenju, Song; Chaoyang, Tong; Zhengang, Tao

    2017-01-01

    Chemoresistance has become a an important worldwide problem to cancer treatment. Understanding the mechanism of drug resistance is the key to solve this problem and improve the survival of the patient. Doxorubicin and its analogues are widely used as antitumor drugs but many doxorubicin resistant cases have been identified in recent years. Doxorubicin (Dox) resistance is a very serious phenomenon in lung cancer treatment. As we could show previously, Shufeng Jiedu Capsule (SFJDC) can effectively reverse H69AR cells resistance to Dox, thus, the present study was designed to explore the mechanism underlying the effects of the main ingredient Emodin on chemosensitivity of H69AR cells to Dox. First, the growth inhibition rate of lung cancer cells and normal bronchial epithelial cells (BECs) was determined by MTT. Then, the resistance-induced epithelial-mesenchymal transition (EMT) of H69AR cells was examined by western blot and the effect of Emodin on Twist, Snail or Slug was assayed by Real-time PCR and Western blot. The activation of NF-kappa B was assayed by Western blot. Proliferation, apoptosis, migration and invasion of H69AR cells induced by Twist, Snail and Slug were also assayed by flow cytometry and transwell chamber. The results showed that after administration of Dox (10µM) with different concentrations of Emodin, the cells exhibited a dose-dependent inhibition action to H69AR cells at 48 hours. H69AR induced the expression of Twist, Snail, and Slug when compared with Dox-sensitive H69 cells. The expression of Twist, Snail, and Slug can be effectively inhibited by combination of Dox and Emodin. The reversal of resistance was associated with the inhibition of NF-kappa B. Twist, Snail and Slug promoted proliferation, migration and invasion and inhibited apoptosis. Our data suggest that Emodin can effectively reverse the resistance of H69AR to Dox, an effect paralleled by inhibition of EMT, cell proliferation, apoptosis, migration and invasion. © 2017 The

  6. Phthalocyanine induced phototherapy coupled with Doxorubicin; a promising novel treatment for breast cancer.

    Science.gov (United States)

    Aniogo, Eric Chekwube; George, Blassan Plackal Adimuriyil; Abrahamse, Heidi

    2017-08-01

    Globally, breast cancer is the most common life-threatening malignant disease among women. Adjuvant chemotherapeutic treatment of anthracycline-based chemotherapy (e.g., doxorubicin) has been shown to be more advantageous over non-anthracycline-based therapies, yet possess the tenacity of developing resistance and potential side effects which have limited its use in the clinical setting. These reasons necessitate combining doxorubicin with emerging photodynamic treatment regimens. Areas covered: In this review, the authors have concisely explained doxorubicin chemotherapy and the photobiological processes of phthalocyanine triggered photodynamic therapy (PDT). A literature search was conducted and reports demonstrating the use of doxorubicin and photodynamic therapy as a treatment modality for breast cancer were identified. More emphasis was made on studies demonstrating the efficacy and improved anticancer effect of combining chemotherapy with photodynamic therapy. However, it was concluded that for this combination therapy, still in it's infancy, it could be relevant when integrated into standard treatment. Expert Commentary: To these effects, comprehensive models based on experimental evaluations are needed for rational design of anthracycline-based chemotherapy and PDT to be integrated into the clinical setting.

  7. ENGOT-ov-6/TRINOVA-2: Randomised, double-blind, phase 3 study of pegylated liposomal doxorubicin plus trebananib or placebo in women with recurrent partially platinum-sensitive or resistant ovarian cancer.

    Science.gov (United States)

    Marth, Christian; Vergote, Ignace; Scambia, Giovanni; Oberaigner, Willi; Clamp, Andrew; Berger, Regina; Kurzeder, Christian; Colombo, Nicoletta; Vuylsteke, Peter; Lorusso, Domenica; Hall, Marcia; Renard, Vincent; Pignata, Sandro; Kristeleit, Rebecca; Altintas, Sevilay; Rustin, Gordon; Wenham, Robert M; Mirza, Mansoor Raza; Fong, Peter C; Oza, Amit; Monk, Bradley J; Ma, Haijun; Vogl, Florian D; Bach, Bruce A

    2017-01-01

    Trebananib, a peptide-Fc fusion protein, inhibits angiogenesis by inhibiting binding of angiopoietin-1/2 to the receptor tyrosine kinase Tie2. This randomised, double-blind, placebo-controlled phase 3 study evaluated whether trebananib plus pegylated liposomal doxorubicin (PLD) improved progression-free survival (PFS) in patients with recurrent epithelial ovarian cancer. Women with recurrent ovarian cancer (platinum-free interval ≤12 months) were randomised to intravenous PLD 50 mg/m(2) once every 4 weeks plus weekly intravenous trebananib 15 mg/kg or placebo. PFS was the primary end-point; key secondary end-points were objective response rate (ORR) and duration of response (DOR). Owing to PLD shortages, enrolment was paused for 13 months; the study was subsequently truncated. Two hundred twenty-three patients were enrolled. Median PFS was 7.6 months (95% CI, 7.2-9.0) in the trebananib arm and 7.2 months (95% CI, 4.8-8.2) in the placebo arm, with a hazard ratio of 0.92 (95% CI, 0.68-1.24). However, because the proportional hazards assumption was not fulfilled, the standard Cox model did not provide a reliable estimate of the hazard ratio. ORR in the trebananib arm was 46% versus 21% in the placebo arm (odds ratio, 3.43; 95% CI, 1.78-6.64). Median DOR was improved (trebananib, 7.4 months [95% CI, 5.7-7.6]; placebo, 3.9 months [95% CI, 2.3-6.5]). Adverse events with a greater incidence in the trebananib arm included localised oedema (61% versus 32%), ascites (29% versus 9%) and vomiting (45% versus 33%). Trebananib demonstrated anticancer activity in this phase 3 study, indicated by improved ORR and DOR. Median PFS was not improved. No new safety signals were identified. ClinicalTrials.gov, NCT01281254. Copyright © 2016. Published by Elsevier Ltd.

  8. Non-destructive reversible resistive switching in Cr doped Mott insulator Ca2RuO4: Interface vs bulk effects

    KAUST Repository

    Shen, Shida

    2017-12-29

    A non-destructive reversible resistive switching is demonstrated in single crystals of Cr-doped Mott insulator Ca2RuO4. An applied electrical bias was shown to reduce the DC resistance of the crystal by as much as 75%. The original resistance of the sample could be restored by applying an electrical bias of opposite polarity. We have studied this resistive switching as a function of the bias strength, applied magnetic field, and temperature. A combination of 2-, 3-, and 4-probe measurements provide a means to distinguish between bulk and interfacial contributions to the switching and suggests that the switching is mostly an interfacial effect. The switching was tentatively attributed to electric-field driven lattice distortions which accompany the impurity-induced Mott transition. This field effect was confirmed by temperature-dependent resistivity measurements which show that the activation energy of this material can be tuned by an applied DC electrical bias. The observed resistance switching can potentially be used for building non-volatile memory devices like resistive random access memory.

  9. Combination of siRNA-directed Gene Silencing With Cisplatin Reverses Drug Resistance in Human Non-small Cell Lung Cancer

    Directory of Open Access Journals (Sweden)

    Shanthi Ganesh

    2013-01-01

    Full Text Available One of the most challenging aspects of lung cancer therapy is the rapid acquisition of multidrug-resistant (MDR phenotype. One effective approach would be to identify and downregulate resistance-causing genes in tumors using small interfering RNAs (siRNAs to increase the sensitivity of tumor cells to chemotherapeutic challenge. After identifying the overexpressed resistance-related antiapoptotic genes (survivin and bcl-2 in cisplatin-resistant cells, the siRNA sequences were designed and screened to select the most efficacious candidates. Modifications were introduced in them to minimize off-target effects. Subsequently, the combination of siRNA and cisplatin that gave the maximum synergy was identified in resistant cells. We then demonstrated that the combination treatment of the selected siRNAs and cisplatin encapsulated in CD44-targeting hyaluronic acid (HA-based self-assembling nanosystems reversed the resistance to cisplatin and delayed the tumor growth significantly (growth inhibition increased from 30 to 60% in cisplatin-resistant tumors. In addition, no abnormalities in body weights, liver enzyme levels or histopathology of liver/spleen tissues were observed in any of the treatment groups during the study period. Overall, we demonstrate that the combination of siRNA-mediated gene-silencing strategy with chemotherapeutic agents constitutes a valuable and safe approach for the treatment of MDR tumors.

  10. The prevalence of resistance-associated mutations to protease and reverse transcriptase inhibitors in treatment-naïve (HIV1)-infected individuals in Casablanca, Morocco.

    Science.gov (United States)

    Bakhouch, Khadija; Oulad-Lahcen, Ahd; Bensghir, Rajae; Blaghen, Mohamed; Elfilali, Kamal Marhoum; Ezzikouri, Sayeh; Abidi, Omar; Hassar, Mohamed; Wakrim, Lahcen

    2009-06-01

    The widespread use of antiretroviral agents and the growing occurrence of HIV-1 strains resistant to these drugs have given rise to serious concerns regarding the transmission of resistant viruses to newly infected persons, which may reduce the efficacy of a first-line antiretroviral therapy. RNA was extracted from plasma samples of 98 treatment-naïve individuals with a plasma HIV RNA viral load of at least 1,000 copies/ml. Both protease (pr) and reverse transcriptase (rt) were amplified and sequenced using an automated sequencer. National Agency for AIDS Research (ANRS) and Stanford HIV database algorithms were used for interpretation of resistance data. In the protease segment, various minor mutations were present in the majority of the sequenced samples with high frequencies. Only two major mutations, M46L and V82L, were separately found in three individuals of 71 (4.2%) with one carrying both mutations. In the reverse transcriptase gene, no NNRTIs-associated resistance mutations were detected. Only one patient of 70 (1.4%) carried the F77L mutation that is associated with NRTIs resistance. Genetic subtyping revealed that 74.6% of samples were infected with subtype B, 15.5% with CRF02_AG, 4.2% with CRF01_AE, 1.4% with C, 2.8% with G and 1.4% with subtype F2. The low prevalence of major mutations associated with resistance to antiretroviral drugs (ARVs) among drug-naïve individuals studied suggests that the routine of drug resistance testing may be unnecessary for all Moroccan individuals newly diagnosed or all patients beginning antiretroviral therapy. Nevertheless, continuous surveillance is required since greater access to antiretroviral drugs is expected in Morocco.

  11. Folic acid-conjugated graphene oxide as a transporter of chemotherapeutic drug and siRNA for reversal of cancer drug resistance

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Xiufen; Feng, Fuli; Wang, Yinsong; Yang, Xiaoying, E-mail: yangxiaoying@tijmu.edu.cn; Duan, Hongquan [Tianjin Medical University, Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics (Theranostics), Basic Medical Research Center, School of Pharmacy (China); Chen, Yongshen, E-mail: yschen99@nankai.edu.cn [College of Chemistry, Nankai University, Center for Nanoscale Science and Technology and Key Laboratory of Functional Polymer Materials, Institute of Polymer Chemistry (China)

    2013-10-15

    Functionalized graphene oxide (GO) with folic acid-conjugated chitosan oligosaccharide (FACO) containing quaternary ammonium groups (GO-FACO{sup +}) was successfully prepared. The formation and composition of GO-FACO{sup +} were confirmed by FTIR, UV-Vis, AFM, TGA, and zeta-potential. Cell experiments show that cellular uptake of fluorescein FAM-labeled DNA sequence (FAM-DNA) delivered by GO-FACO{sup +} exhibits higher efficiency in doxorubicin chloride (Dox)-resistant MCF-7 human breast cancer cells (MCF-7/Dox) with folate receptor overexpressed than that delivered by chitosan oligosaccharide (CO)-functionalized graphene oxides (GO-CO{sup +}) without folic acid modification and in human lung cancer A549 cells with folate receptor negatively expressed. The loading efficiency of Dox on GO-FACO{sup +} was 568.4 {mu}g mg{sup -1} at the initial Dox concentration of 0.5 mg mL{sup -1}, and in vitro release of Dox showed strong pH dependence. MDR1 siRNA transfected by GO-FACO{sup +} could efficiently knockdown the MDR1 mRNA and P-gp expression levels in MCF-7/Dox cells. GO-FACO{sup +} shows no obvious toxicity even at 500 {mu}g mL{sup -1}. The sequential deliveries of MDR1 siRNA and Dox by GO-FACO{sup +} exhibited much higher cytotoxicity against MCF-7/Dox cells than only delivery of Dox by GO-FACO{sup +} when Dox concentration is lower than 25 {mu}g mL{sup -1}, while excess 80 % cells were killed in the two cases when Dox concentration is higher than 30 {mu}g mL{sup -1}. Taken together, this functionalized GO has potential applications for targeted intracellular delivery of anti-tumor drugs and genes.

  12. Pegylated liposomal doxorubicin: appraisal of its current role in the management of epithelial ovarian cancer

    OpenAIRE

    Markman M

    2011-01-01

    Maurie MarkmanCancer Treatment Centers of America, Eastern Regional Medical Center, Philadelphia, PA, USAAbstract: Pegylated liposomal doxorubicin (PLD) has become a major component in the routine management of epithelial ovarian cancer. The drug is frequently employed as a single agent in the platinum-resistant setting, and recently reported data reveal the superiority of the combination of PLD plus carboplatin, compared with the platinum drug plus paclitaxel, in delaying the time to disease...

  13. Polymorphisms in the multiple drug resistance protein 1 and in P-glycoprotein 1 are associated with time to event outcomes in patients with advanced multiple myeloma treated with bortezomib and pegylated liposomal doxorubicin

    NARCIS (Netherlands)

    G. Buda (Gabriele); D. Ricci (Deborah); C.C. Huang (Chris); R. Favis (Reyna); N. Cohen (Nadine); S.H. Zhuang (Sen); J-L. Harousseau (Jean-Luc); P. Sonneveld (Pieter); J. Bladé (Joan); R.Z. Orlowski (Robert)

    2010-01-01

    textabstractSingle nucleotide polymorphisms (SNPs) in the multiple drug resistance protein 1 (MRP1) and P-glycoprotein 1 (MDR1) genes modulate their ability to mediate drug resistance. We therefore sought to retrospectively evaluate their influence on outcomes in relapsed and/or refractory myeloma

  14. Synthesis and biological evaluation of novel peptides based on antimicrobial peptides as potential agents with antitumor and multidrug resistance-reversing activities.

    Science.gov (United States)

    Zhang, Bo; Shi, Wei; Li, Jieming; Liao, Chen; Yang, Limei; Huang, Wenlong; Qian, Hai

    2017-11-01

    Tumor chemotherapy, which plays an important role in the clinical treatment of metastatic cancer, is limited by low selectivity and drug resistance in clinical application. In our study, we selected antimicrobial peptide BP100 as a lead peptide, designed, and synthesized a series of novel antineoplastic peptides through solid-phase synthesis. Among them, B4 and B8 showed excellent anticancer activity. As revealed by further investigations, these peptides could disrupt the cell membrane, trigger the cytochrome C release into cytoplasm, and ultimately lead to apoptosis. In addition, they also showed multidrug resistance-reversing effects by performing effective antitumor activity against multidrug-resistant cells. As a result, these peptides may possibly be regarded as a promising candidate for cancer treatment. © 2017 John Wiley & Sons A/S.

  15. Mechanistic Study of Common Non-Nucleoside Reverse Transcriptase Inhibitor-Resistant Mutations with K103N and Y181C Substitutions

    Directory of Open Access Journals (Sweden)

    Ming-Tain Lai

    2016-09-01

    Full Text Available Non-nucleoside reverse transcriptase inhibitors (NNRTIs are a mainstay of therapy for human immunodeficiency type 1 virus (HIV-1 infections. However, their effectiveness can be hampered by the emergence of resistant mutations. To aid in designing effective NNRTIs against the resistant mutants, it is important to understand the resistance mechanism of the mutations. Here, we investigate the mechanism of the two most prevalent NNRTI-associated mutations with K103N or Y181C substitution. Virus and reverse transcriptase (RT with K103N/Y188F, K103A, or K103E substitutions and with Y181F, Y188F, or Y181F/Y188F substitutions were employed to study the resistance mechanism of the K103N and Y181C mutants, respectively. Results showed that the virus and RT with K103N/Y188F substitutions displayed similar resistance levels to the virus and RT with K103N substitution versus NNRTIs. Virus and RT containing Y181F, Y188F, or Y181F/Y188F substitution exhibited either enhanced or similar susceptibility to NNRTIs compared with the wild type (WT virus. These results suggest that the hydrogen bond between N103 and Y188 may not play an important role in the resistance of the K103N variant to NNRTIs. Furthermore, the results from the studies with the Y181 or Y188 variant provide the direct evidence that aromatic π–π stacking plays a crucial role in the binding of NNRTIs to RT.

  16. K70Q adds high-level tenofovir resistance to "Q151M complex" HIV reverse transcriptase through the enhanced discrimination mechanism.

    Directory of Open Access Journals (Sweden)

    Atsuko Hachiya

    2011-01-01

    Full Text Available HIV-1 carrying the "Q151M complex" reverse transcriptase (RT mutations (A62V/V75I/F77L/F116Y/Q151M, or Q151Mc is resistant to many FDA-approved nucleoside RT inhibitors (NRTIs, but has been considered susceptible to tenofovir disoproxil fumarate (TFV-DF or TDF. We have isolated from a TFV-DF-treated HIV patient a Q151Mc-containing clinical isolate with high phenotypic resistance to TFV-DF. Analysis of the genotypic and phenotypic testing over the course of this patient's therapy lead us to hypothesize that TFV-DF resistance emerged upon appearance of the previously unreported K70Q mutation in the Q151Mc background. Virological analysis showed that HIV with only K70Q was not significantly resistant to TFV-DF. However, addition of K70Q to the Q151Mc background significantly enhanced resistance to several approved NRTIs, and also resulted in high-level (10-fold resistance to TFV-DF. Biochemical experiments established that the increased resistance to tenofovir is not the result of enhanced excision, as K70Q/Q151Mc RT exhibited diminished, rather than enhanced ATP-based primer unblocking activity. Pre-steady state kinetic analysis of the recombinant enzymes demonstrated that addition of the K70Q mutation selectively decreases the binding of tenofovir-diphosphate (TFV-DP, resulting in reduced incorporation of TFV into the nascent DNA chain. Molecular dynamics simulations suggest that changes in the hydrogen bonding pattern in the polymerase active site of K70Q/Q151Mc RT may contribute to the observed changes in binding and incorporation of TFV-DP. The novel pattern of TFV-resistance may help adjust therapeutic strategies for NRTI-experienced patients with multi-drug resistant (MDR mutations.

  17. Cigarette smoke promotes drug resistance and expansion of cancer stem cell-like side population.

    Science.gov (United States)

    An, Yi; Kiang, Alan; Lopez, Jay Patrick; Kuo, Selena Z; Yu, Michael Andrew; Abhold, Eric L; Chen, Jocelyn S; Wang-Rodriguez, Jessica; Ongkeko, Weg M

    2012-01-01

    It is well known that many patients continue to smoke cigarettes after being diagnosed with cancer. Although smoking cessation has typically been presumed to possess little therapeutic value for cancer, a growing body of evidence suggests that continued smoking is associated with reduced efficacy of treatment and a higher incidence of recurrence. We therefore investigated the effect of cigarette smoke condensate (CSC) on drug resistance in the lung cancer and head and neck cancer cell lines A549 and UMSCC-10B, respectively. Our results showed that CSC significantly increased the cellular efflux of doxorubicin and mitoxantrone. This was accompanied by membrane localization and increased expression of the multi-drug transporter ABCG2. The induced efflux of doxorubicin was reversed upon addition of the specific ABCG2 inhibitor Fumitremorgin C, confirming the role of ABCG2. Treatment with CSC increased the concentration of phosphorylated Akt, while addition of the PI3K inhibitor LY294002 blocked doxorubicin extrusion, suggesting that Akt activation is required for CSC-induced drug efflux. In addition, CSC was found to promote resistance to doxorubicin as determined by MTS assays. This CSC-induced doxurbicin-resistance was mitigated by mecamylamine, a nicotinic acetylcholine receptor inhibitor, suggesting that nicotine is at least partially responsible for the effect of CSC. Lastly, CSC increased the size of the side population (SP), which has been linked to a cancer stem cell-like phenotype. In summary, CSC promotes chemoresistance via Akt-mediated regulation of ABCG2 activity, and may also increase the proportion of cancer stem-like cells, contributing to tumor resilience. These findings underscore the importance of smoking cessation following a diagnosis of cancer, and elucidate the mechanisms of continued smoking that may be detrimental to treatment.

  18. Cigarette smoke promotes drug resistance and expansion of cancer stem cell-like side population.

    Directory of Open Access Journals (Sweden)

    Yi An

    Full Text Available It is well known that many patients continue to smoke cigarettes after being diagnosed with cancer. Although smoking cessation has typically been presumed to possess little therapeutic value for cancer, a growing body of evidence suggests that continued smoking is associated with reduced efficacy of treatment and a higher incidence of recurrence. We therefore investigated the effect of cigarette smoke condensate (CSC on drug resistance in the lung cancer and head and neck cancer cell lines A549 and UMSCC-10B, respectively. Our results showed that CSC significantly increased the cellular efflux of doxorubicin and mitoxantrone. This was accompanied by membrane localization and increased expression of the multi-drug transporter ABCG2. The induced efflux of doxorubicin was reversed upon addition of the specific ABCG2 inhibitor Fumitremorgin C, confirming the role of ABCG2. Treatment with CSC increased the concentration of phosphorylated Akt, while addition of the PI3K inhibitor LY294002 blocked doxorubicin extrusion, suggesting that Akt activation is required for CSC-induced drug efflux. In addition, CSC was found to promote resistance to doxorubicin as determined by MTS assays. This CSC-induced doxurbicin-resistance was mitigated by mecamylamine, a nicotinic acetylcholine receptor inhibitor, suggesting that nicotine is at least partially responsible for the effect of CSC. Lastly, CSC increased the size of the side population (SP, which has been linked to a cancer stem cell-like phenotype. In summary, CSC promotes chemoresistance via Akt-mediated regulation of ABCG2 activity, and may also increase the proportion of cancer stem-like cells, contributing to tumor resilience. These findings underscore the importance of smoking cessation following a diagnosis of cancer, and elucidate the mechanisms of continued smoking that may be detrimental to treatment.

  19. A novel sensitive doxorubicin impedimetric immunosensor based on a specific monoclonal antibody-gold nanoaprticle-sol-gel modified electrode.

    Science.gov (United States)

    Rezaei, Behzad; Askarpour, Neda; Ensafi, Ali A

    2014-02-01

    In this work, ultrasensitive electrochemical doxorubicin impedance immunosensor was investigated based on immobilization of a specific monoclonal antibody on gold nanoparticles (GNPs) associated with a thiol base sol-gel (TBSol-Gel) modified gold electrode. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were employed for characterization of the various layers that were formed at the electrode surface. The redox couples of 1.0 mmol L(-1), Fe(CN)6(4-/3-) species on the electrode surface was followed to study the layers formation and determination process, using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). After optimization of analytical parameters, the relative charge transfer resistance (Rct) increases linearly with doxorubicin concentration in the ranges of 0.1-1.0 and 2.5-50.0 pg mL(-1), with a detection limit of 0.09 pg mL(-1). A high association constant of 1.4 × 10(11) L mol(-1) was obtained for the affinity of doxorubicin toward the immobilized antibody on the electrode surface. The capability of the proposed immunosensor for the determination of doxorubicin in spiked human serum and urine samples was examined by standard addition method, and the results show that the immunosensor is a useful tool for the determination of doxorubicin in the biological samples. © 2013 Published by Elsevier B.V.

  20. Evaluation of the pharmacokinetics and cardiotoxicity of doxorubicin in rat receiving nilotinib

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Zhi-yong [Department of Pharmacy, Affiliated Sixth People' s Hospital, Shanghai Jiao Tong University, 200233 Shanghai (China); School of Pharmacy, Shanghai Jiao Tong University, 200240 Shanghai (China); Wan, Li-li; Yang, Quan-jun; Han, Yong-long; Li, Yan; Yu, Qi [Department of Pharmacy, Affiliated Sixth People' s Hospital, Shanghai Jiao Tong University, 200233 Shanghai (China); Guo, Cheng, E-mail: guochengphd@yahoo.com.cn [Department of Pharmacy, Affiliated Sixth People' s Hospital, Shanghai Jiao Tong University, 200233 Shanghai (China); School of Pharmacy, Shanghai Jiao Tong University, 200240 Shanghai (China); Li, Xiao, E-mail: lixiao3326@yahoo.com.cn [Department of Hematology, Affiliated Sixth people' s Hospital, Shanghai Jiao Tong University, 200233 Shanghai (China)

    2013-10-01

    Doxorubicin (DOX) is a potent chemotherapy drug with a narrow therapeutic window. Nilotinib, a small-molecule Bcr-Abl tyrosine kinase inhibitor, was reported to reverse multidrug resistance (MDR) mediated by P-glycoprotein (P-gp) transmembrane transporters. The present study aimed to investigate nilotinib's affection on the steady-state pharmacokinetics, disposition and cardiotoxicity of DOX. A total of 24 male Sprague–Dawley rats were randomized into four groups (6 in each) and received the following regimens: saline, intravenous DOX (5 mg/kg) alone, and DOX co-administrated with either 20 or 40 mg/kg nilotinib. Blood was withdrawn at 12 time points till 72 h after DOX injection and the concentrations of DOX and its metabolite doxorubicinol (DOXol) in serum and cardiac tissue were assayed by LC–MS–MS method. To determine the cardiotoxicity, the following parameters were investigated: creatine kinase, lactate dehydrogenase, malondialdehyde, and superoxide dismutase. Histopathological examination of heart section was carried out to evaluate the extent of cardiotoxicity after treatments. The results showed that pretreatment of 40 mg/kg nilotinib increased the AUC{sub 0–t} and C{sub max} of DOX and DOXol. However, their accumulation in cardiac tissue was significantly decreased when compared with the group that received DOX alone. In addition, biochemical and histopathological results showed that 40 mg/kg nilotinib reduced the cardiotoxicity induced by DOX administration. In conclusion, co-administration of nilotinib increased serum exposure, but significantly decreased the accumulation of DOX in cardiac tissue. Consistent with in vitro profile, oral dose of 40 mg/kg nilotinib significantly decreased the cardiotoxicity of DOX in rat by enhancing P-gp activity in the heart.

  1. Dahuang Zhechong Pill Combined with Doxorubicin Induces Cell Death through Regulating Energy Metabolism in Human Hepatocellular Carcinoma Cells

    Directory of Open Access Journals (Sweden)

    Li Wu

    2017-01-01

    Full Text Available Many physiological activities such as cell survival, proliferation, defense, adaptation, and metabolism need to consume energy. Hepatoma cells can quickly start stress responses like multidrug resistance (MDR requiring adenosine triphosphate (ATP consumption after administration of chemotherapeutics. We employed CCK-8 assay to evaluate cell viability and the flow cytometry to confirm apoptosis and necrosis. ELISA kit was used to determine intracellular levels of ATP in lysates. Western blot was employed to analyze the expressions of key enzymes involved in energy metabolism. We found that doxorubicin (DOX potently stimulated apoptosis at a low dose and even induced necrosis at a high dose in SMMC-7721. DHZCP combined with DOX at low or middle dose enhanced the synergistic antihepatoma effect. Results indicated that Dahuang Zhechong Pill (DHZCP inhibited the expressions of several key enzymes involved in oxidative phosphorylation and reduced intracellular ATP levels. The combination of DHZCP with DOX reversed the elevation of intracellular ATP levels, and a significantly synergistic antitumor effect was observed. DHZCP could not only strengthen the therapeutic effects of chemotherapeutic drugs but also decrease the doses of chemotherapeutic drugs and the incidences of adverse reactions, providing novel strategies for clinical treatment of liver cancer.

  2. miR-495 sensitizes MDR cancer cells to the combination of doxorubicin and taxol by inhibiting MDR1 expression.

    Science.gov (United States)

    Zou, Zhenyou; Zou, Ruyi; Zong, Dan; Shi, Yonghong; Chen, Jinyao; Huang, Jie; Zhu, Jiahui; Chen, Liguan; Bao, Xiaoyan; Liu, Yuan; Liu, Weihao; Huang, Wenhui; Hu, Jingsang; Chen, Zhi; Lao, Xiaojie; Chen, Chaoqun; Huang, Xiaoli; Lu, Yao; Ni, Xueyin; Fang, Daoquan; Wu, Dengqiang; Lu, Shuangshuang; Jiang, Mingzhu; Qiu, Chenyang; Wu, Yuya; Qiu, Qisha; Dong, Yanyuan; Su, Yangyang; Zhao, Chenmin; Zhong, Zhihe; Cai, Jing; Liang, Yong

    2017-09-01

    MDR1 is highly expressed in MDR A2780DX5 ovarian cancer cells, MDR SGC7901R gastric cancer cells and recurrent tumours. It pumps cytoplasmic agents out of cells, leading to decreased drug accumulation in cells and making cancer cells susceptible to multidrug resistance. Here, we identified that miR-495 was predicted to target ABCB1, which encodes protein MDR1. To reduce the drug efflux and reverse MDR in cancer cells, we overexpressed a miR-495 mimic in SGC7901R and A2780DX cells and in transplanted MDR ovarian tumours in vivo. The results indicated that the expression of MDR1 in the above cells or tumours was suppressed and that subsequently the drug accumulation in the MDR cells was decreased, cell death was increased, and tumour growth was inhibited after treatment with taxol-doxorubicin, demonstrating increased drug sensitivity. This study suggests that pre-treatment with miR-495 before chemotherapy could improve the curative effect on MDR1-based MDR cancer. © 2017 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

  3. Pegylated liposomal doxorubicin in ovarian cancer

    OpenAIRE

    Matei, Daniela

    2009-01-01

    Robert Strother1,2, Daniela Matei1–51Department of Medicine, 2Indiana University Melvin and Bren Simon Cancer Center, 3Department of Obstetrics and Gynecology, 4Department of Biochemistry and Molecular Biology, 5VA Roudebush Hospital Indiana University School of Medicine, 535 Barnhill Drive, Indianapolis, IN, 46202Abstract: The encapsulation of doxorubicin in a pegylated liposomal matrix led to a reformulated agent with a different toxicity profile and improved clinical utility. Lip...

  4. The case for addressing primary resistance mutations to non-nucleoside reverse transcriptase inhibitors to treat children born from mothers living with HIV in sub-Saharan Africa

    OpenAIRE

    Khady Kébé; Laurent Bélec; Halimatou Diop Ndiaye; Sokhna Bousso Gueye; Abou Abdallah Malick Diouara; Safiétou Ngom; Ndéye Rama Diagne Gueye; Ngagne Mbaye; Haby Signaté Sy; Souleymane Mboup; Coumba Touré Kane

    2014-01-01

    The prevalence of human immunodeficiency virus (HIV) drug resistance mutations (DRMs) was estimated in 25 untreated infants who were living with HIV-1, younger than 13 months and living in Senegal. Antiretroviral DRMs were detected in 8 of 25 (32%) children. Non-nucleoside reverse transcriptase inhibitor (NNRTI) DRMs were present in all (100%) children whose viruses harboured DRMs: K103N in 43%; Y181C, K101E and V106M each in 29%; and Y188L in 14%. The D67N thymidine-analogue mutation was obs...

  5. INPP4B reverses docetaxel resistance and epithelial-to-mesenchymal transition via the PI3K/Akt signaling pathway in prostate cancer

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Haiwen; Li, Hongliang, E-mail: honglianglity@sina.com; Chen, Qi

    2016-08-26

    Docetaxel efficiency in the therapy of prostate cancer (PCa) patients is limited due to the development of chemoresistance. Recent studies have implied a role of INPP4B in tumor chemoresistance, while the effects of INPP4B on docetaxel resistance in PCa have not been elucidated. In the present study, the docetaxel-resistant human PCa cell lines PC3-DR and DU-145-DR were established from the parental cell lines PC3 and DU-145, and the expression and role of INPP4B in docetaxel-resistant PCa cells were investigated. The results demonstrated that INPP4B expression was significantly downregulated in docetaxel-resistant cells. Overexpression of INPP4B increased the sensitivity to docetaxel and promoted cell apoptosis in PC3-DR and DU-145-DR cells. In addition, INPP4B overexpression downregulated the expression of the mesenchymal markers fibronectin, N-cadherin, and vimentin, and upregulated the expression level of the epithelial maker E-cadherin. Furthermore, INPP4B overexpression markedly inhibited the PI3K/Akt pathway. We also found that IGF-1, the inhibitor of PI3K/Akt, markedly blocked the change in EMT markers induced by overexpression of INPP4B, and reversed the resistance of PC3-DR and DU-145-DR cells to docetaxel, which is sensitized by Flag-INPP4B. In summary, the presented data indicate that INPP4B is crucial for docetaxel-resistant PCa cell survival, potentially by regulating EMT through the PI3K/Akt signaling pathway. - Highlights: • INPP4B is downregulated in docetaxel-resistant PCa cells. • INPP4B inhibits cell proliferation. • INPP4B induces cell apoptosis. • INPP4B inhibits PCa cell EMT.

  6. Reversal of chemoresistance with small interference RNA (siRNA) in etoposide resistant acute myeloid leukemia cells (HL-60).

    Science.gov (United States)

    Kachalaki, Saeed; Baradaran, Behzad; Majidi, Jafar; Yousefi, Mehdi; Shanehbandi, Dariush; Mohammadinejad, Sina; Mansoori, Behzad

    2015-10-01

    Overexpression of ATP-binding cassette (ABC) drug transporters is a major barrier in the success of cancer chemotherapy. One way to overcome overexpression of ABC drug transporter-mediated chemoresistance in acute myeloid leukemia is to suppress ABC drug transporter genes expression by small interference RNA (siRNA). In this study was assessed the involvement of ABCB1 gene in the mechanisms of resistance to etoposide in AML cells. The etoposide-resistant HL-60 cells were generated by stepwise exposure increasing concentrations of etoposide. The etoposide-resistant HL-60 cells were transfected with siRNAs using Transfection Reagent. The ABCB1 mRNA expression were assessed by real-time quantitative PCR. The MDR1/P-gp levels were measured by Western blotting. The sensitivity of resistant HL-60 cells to etoposide after transfection was determined using MTT assay. Apoptosis of resistant HL-60 cells after transfection was detected by flow cytometer. It was found that siRNA effectively inhibited ABCB1 expression at both mRNA and protein levels. Knockdown of the ABCB1 gene correlated with increased sensitivity of the resistant HL-60 cells to etoposide and was observed to lower the cytotoxic index (IC50 etoposide value) after transfection. Our results indicate that product of the ABCB1 gene have effective role in resistance to etoposide in acute myeloid leukemia cells. Copyright © 2015. Published by Elsevier Masson SAS.

  7. Reversible transition between bipolar and unipolar resistive switching in Cu2O/Ga2O3 binary oxide stacked layer

    Directory of Open Access Journals (Sweden)

    Y. S. Zhi

    2016-01-01

    Full Text Available Both unipolar resistive switching (URS and bipolar resistive switching (BRS behaviors are observed in Cu2O/Ga2O3 stacked layer. The conversion between BRS and URS is controllable and reversible. The switching operations in BRS mode requires smaller voltage than that in the URS mode. The oxygen vacancies closed to the Cu2O/Ga2O3 interface contributes to the BRS, and the bias-controlling filament formation/rupture in depletion layer is considered to contribute to the URS. The URS happens only in the negative voltage part due to the nature of directionality of the p-n junction. The process reported here can be developed to design memory device.

  8. Influence of doxorubicin on fluconazole susceptibility and efflux pump gene expression of Candida dubliniensis.

    LENUS (Irish Health Repository)

    Schulz, Bettina

    2012-05-01

    The effect of doxorubicin (DOX) on the fluconazole (FLU) susceptibility of C. dubliniensis was investigated. Isolates were exposed to DOX and FLU in a chequerboard assay and resistance gene expressions were analysed after DOX exposure. The susceptibility of the yeast to FLU was decreased in the presence of DOX in the chequerboard assay with FIC indices suggesting an antagonistic effect. Gene expression analyses showed an overexpression of CdCDR2. Hence, DOX was found to have an impact on resistance mechanisms in C. dubliniensis isolates.

  9. Using Quantitative Reverse Transcriptase PCR and Cell Culture Plaque Assays to Determine Resistance of Toxoplasma gondii Oocysts to Chemical Sanitizers

    Science.gov (United States)

    Toxoplasma gondii oocysts are highly resistant to many chemical sanitizers. Current methods used to determine oocyst infectivity have relied exclusively on mouse, chicken, and feline bioassays. Although considered gold standards, they only provide a qualitative assessment of oocyst infectivity. I...

  10. HIV-1 phenotypic reverse transcriptase inhibitor drug resistance test interpretation is not dependent on the subtype of the virus backbone.

    Directory of Open Access Journals (Sweden)

    Michelle Bronze

    Full Text Available To date, the majority of HIV-1 phenotypic resistance testing has been performed with subtype B virus backbones (e.g. HXB2. However, the relevance of using this backbone to determine resistance in non-subtype B HIV-1 viruses still needs to be assessed. From 114 HIV-1 subtype C clinical samples (36 ARV-naïve, 78 ARV-exposed, pol amplicons were produced and analyzed for phenotypic resistance using both a subtype B- and C-backbone in which the pol fragment was deleted. Phenotypic resistance was assessed in resulting recombinant virus stocks (RVS for a series of antiretroviral drugs (ARV's and expressed as fold change (FC, yielding 1660 FC comparisons. These Antivirogram® derived FC values were categorized as having resistant or sensitive susceptibility based on biological cut-off values (BCOs. The concordance between resistance calls obtained for the same clinical sample but derived from two different backbones (i.e. B and C accounted for 86.1% (1429/1660 of the FC comparisons. However, when taking the assay variability into account, 95.8% (1590/1660 of the phenotypic data could be considered as being concordant with respect to their resistance call. No difference in the capacity to detect resistance associated with M184V, K103N and V106M mutations was noted between the two backbones. The following was concluded: (i A high level of concordance was shown between the two backbone phenotypic resistance profiles; (ii Assay variability is largely responsible for discordant results (i.e. for FC values close to BCO; (iii Confidence intervals should be given around the BCO's, when assessing resistance in HIV-1 subtype C; (iv No systematic resistance under- or overcalling of subtype C amplicons in the B-backbone was observed; (v Virus backbone subtype sequence variability outside the pol region does not contribute to phenotypic FC values. In conclusion the HXB2 virus backbone remains an acceptable vector for phenotyping HIV-1 subtype C pol amplicons.

  11. Oridonin effectively reverses the drug resistance of cisplatin involving induction of cell apoptosis and inhibition of MMP expression in human acute myeloid leukemia cells

    Directory of Open Access Journals (Sweden)

    Yuan Zhang

    2017-03-01

    Full Text Available Cisplatin is the first generation platinum-based chemotherapy agent. However, the extensive application of cisplatin inevitably causes drug resistance, which is a major obstacle to cancer chemotherapy. Oridonin is a diterpenoid isolated from Rabdosia rubescens with potent anticancer activity. The aim of our study is to investigate the role of oridonin to reverse the cisplatin-resistance in human acute myeloid leukemia (AML cells. The effect of oridonin on human AML cell proliferation was evaluated by MTT assay, cell migration and invasion were evaluated by transwell migration and invasion assays in cisplatin-resistant human AML cells. Furthermore, cell apoptosis was examined by flow cytometry. The inhibitive effect of oridonin in vivo was determined using xenografted nude mice. In addition, the expressions of MMP2 and MMP9 were detected by Western blot. There was a synergistic antitumor effect between cisplatin and oridonin on cisplatin-resistant human AML cells in vitro and in vivo. In addition, the combination of cisplatin and oridonin synergistically induced cell apoptosis. Furthermore, the combination treatment not only inhibited AML cell migration and invasion, but more significantly, decreased the expressions of MMP2 and MMP9 proteins. Our results suggest that the synergistic effect between both agents is likely to be driven by the inhibition of MMP expression and the resulting increased apoptosis.

  12. Resistive Switching in All-Printed, Flexible and Hybrid MoS2-PVA Nanocomposite based Memristive Device Fabricated by Reverse Offset

    Science.gov (United States)

    Rehman, Muhammad Muqeet; Siddiqui, Ghayas Uddin; Gul, Jahan Zeb; Kim, Soo-Wan; Lim, Jong Hwan; Choi, Kyung Hyun

    2016-11-01

    Owing to the increasing interest in the nonvolatile memory devices, resistive switching based on hybrid nanocomposite of a 2D material, molybdenum disulphide (MoS2) and polyvinyl alcohol (PVA) is explored in this work. As a proof of concept, we have demonstrated the fabrication of a memory device with the configuration of PET/Ag/MoS2-PVA/Ag via an all printed, hybrid, and state of the art fabrication approach. Bottom Ag electrodes, active layer of hybrid MoS2-PVA nanocomposite and top Ag electrode are deposited by reverse offset, electrohydrodynamic (EHD) atomization and electrohydrodynamic (EHD) patterning respectively. The fabricated device displayed characteristic bistable, nonvolatile and rewritable resistive switching behavior at a low operating voltage. A decent off/on ratio, high retention time, and large endurance of 1.28 × 102, 105 sec and 1000 voltage sweeps were recorded respectively. Double logarithmic curve satisfy the trap controlled space charge limited current (TCSCLC) model in high resistance state (HRS) and ohmic model in low resistance state (LRS). Bendability test at various bending diameters (50-2 mm) for 1500 cycles was carried out to show the mechanical robustness of fabricated device.

  13. Mutagenic study of codons 74 and 215 of the human immunodeficiency virus type 1 reverse transcriptase, which are significant in nucleoside analog resistance.

    Science.gov (United States)

    Lacey, S F; Larder, B A

    1994-05-01

    Mutation in the human immunodeficiency virus type 1 reverse transcriptase (RT) at codon 215 has been shown to play a significant role in resistance to zidovudine (AZT). Substitution of threonine with tyrosine or phenylalanine alone confers decreased susceptibility to the inhibitor. In this study we constructed a panel of 10 viruses with different amino acids at this codon, including 7 novel mutants, and assessed their susceptibilities to AZT. The majority of the new mutants were AZT sensitive, whereas the Thr-215-->Trp mutant was partially resistant (threefold less susceptible). A combination of the Thr-215-->Trp with the other AZT resistance mutations Lys-70-->Arg and Met-41-->Leu gave additive resistance. The Thr-215-->Phe virus was less AZT resistant than the Thr-215-->Tyr mutant, both on its own and when each was combined with the Met-41-->Leu mutant. These observations confirm the general hypothesis that increased bulk of the amino acid side chains at this position confers decreased AZT sensitivity. A leucine-to-valine substitution at codon 74 has previously been found to confer dideoxynucleoside resistance. We constructed mutants with five novel amino acid substitutions (Ala, Gly, Glu, Met, and Asp) at codon 74. Of these, only one (that with the Met substitution) retained enough RT activity to yield viable virus. It thus appears that there are severe structure-function constraints on the amino acid side chains at this position in the enzyme. The activities of the Leu-74-->Ala and Leu-74-->Met RT enzymes expressed in Escherichia coli appeared to have reduced susceptibility to ddGTP compared with the wild-type enzyme. The mutants described in this work may prove useful for correlation with structural studies of the human immunodeficiency virus type 1 RT.

  14. Comparison of doxorubicin-cyclophosphamide with doxorubicin-dacarbazine for the adjuvant treatment of canine hemangiosarcoma.

    Science.gov (United States)

    Finotello, R; Stefanello, D; Zini, E; Marconato, L

    2017-03-01

    Canine hemangiosarcoma (HSA) is a neoplasm of vascular endothelial origin that has an aggressive biological behaviour, with less than 10% of dogs alive at 12-months postdiagnosis. Treatment of choice consists of surgery followed by adjuvant doxorubicin-based chemotherapy. We prospectively compared adjuvant doxorubicin and dacarbazine (ADTIC) to a traditional doxorubicin and cyclophosphamide (AC) treatment, aiming at determining safety and assessing whether this regimen prolongs survival and time to metastasis (TTM). Twenty-seven dogs were enrolled; following staging work-up, 18 were treated with AC and 9 with ADTIC. Median TTM and survival time were longer for dogs treated with ADTIC compared with those receiving AC (>550 versus 112 days, P = 0.021 and >550 versus 142 days, P = 0.011, respectively). Both protocols were well tolerated, without need for dose reduction or increased interval between treatments. A protocol consisting of combined doxorubicin and dacarbazine is safe in dogs with HSA and prolongs TTM and survival time. © 2015 John Wiley & Sons Ltd.

  15. Co-delivery of docetaxel and verapamil by reduction-sensitive PEG-PLGA-SS-DTX conjugate micelles to reverse the multi-drug resistance of breast cancer.

    Science.gov (United States)

    Guo, Yuanyuan; He, Wenxiu; Yang, Shengfeng; Zhao, Dujuan; Li, Zhonghao; Luan, Yuxia

    2017-03-01

    The clinical usage of docetaxel (DTX) has been blocked in the clinic because of its poor solubility and tumour multi-drug resistance (MDR). The dominating mechanism of MDR is the over-expression of p-gp on tumour cells. Traditional nano-medicines, such as nanoparticles and micelles, have been used to physically entrap DTX to improve their solubility, while the drug loading content was very low and the tumour resistance was neglected. In this study, the synthesized reduction-sensitive mPEG-PLGA-SS-DTX conjugate was utilized to load the p-gp inhibitor veraparmil (VRP) to prepare DTX and VRP co-delivered mPEG-PLGA-SS-DTX/VRP (PP-SS-DTX/VRP) multi-functional micelles to reverse MDR and enhance the anti-tumour effect of DTX. The micelles had a high drug loading content and showed an obvious reduction-sensitive release property for both DTX and VRP. In addition, an in vitro anti-tumour assay revealed that the micelles markedly inhibited the efflux activity of p-gp and accelerated cell apoptosis, resulting in the improvement of anti-tumour activity and reversal of MDR. The PP-SS-DTX micelles markedly enhanced the in vivo circulation time and increased the drug accumulation in tumour tissues. Therefore, the PP-SS-DTX/VRP micelle is a desirable drug delivery system for multi-drug resistance therapy of DTX and is very promising for clinical usage. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Constitutive expression of the c-H-ras oncogene inhibits doxorubicin-induced apoptosis and promotes cell survival in a rhabdomyosarcoma cell line.

    Science.gov (United States)

    Nooter, K.; Boersma, A. W.; Oostrum, R. G.; Burger, H.; Jochemsen, A. G.; Stoter, G.

    1995-01-01

    Drugs used in anti-cancer chemotherapy are thought to exert their cytotoxic action by induction of apoptosis. Genes have been identified which can mediate or modulate this drug-induced apoptosis, among which are c-myc, p53 and bcl-2. Since expression of oncogenic ras genes is a frequent observation in human cancer, we investigated the effects of the c-H-ras oncogene on anti-cancer drug-induced apoptosis. Apoptosis induced by a 2 h doxorubicin exposure was measured by in situ nick translation and flow cytometry in a rat cell line (R2T24) stably transfected with the c-H-ras oncogene and in a control cell line (R2NEO) transfected only with the antibiotic resistance gene neo. Both cell lines (R2T24 and R2NEO) had nearly identical growth characteristics, including cell doubling time, distribution over the cell cycle phases and plating efficiency in soft agar. Doxorubicin exposure of the R2NEO cells led to massive induction of apoptosis. In contrast, R2T24 cells, expressing the c-H-ras oncogene, showed significantly less apoptosis after doxorubicin incubation. Doxorubicin induced approximately 3- to 5-fold less cytotoxicity in the R2T24 cells than in the R2NEO cells, as determined by clonogenic assay in soft agar. No difference was observed in intracellular doxorubicin accumulation between the two cell lines, indicating that the classical, P-glycoprotein-mediated multidrug resistance phenotype is not involved in the observed differences in drug sensitivity. In conclusion, our data show that constitutive expression of the c-H-ras oncogene suppresses doxorubicin-induced apoptosis and promotes cell survival, suggesting that human tumours with ras oncogene expression might be less susceptible to doxorubicin treatment. PMID:7880739

  17. INFLUENCE OF DOXORUBICIN ON ADHESIVE PROPERTIES OF E.COLI

    Directory of Open Access Journals (Sweden)

    O.G. Shapoval

    2008-09-01

    Full Text Available Influence ofantineoplastic drug doxorubicin and amikacin, the aminoglycoside family on adhesive activity of Escherichia coli was studied. Antimicrobialactivity(minimum inhibitory concentration-MIC ofboth drugs against experimental strains using serial two-fold dilution method was determined. Susceptibility of E.coli to amikacin in the presence of Sand j MIC doxorubicin was studied. After 10 passages in beef-extract broth with constant and increasing doxorubicin concentrations in the presence of Sand j MIC doxorubicin, the adhesive activity of initial and passage variants according to theirability to absorb human erythrocytes 1(0 Rh+ was determined. Itwas observed that experimental strains were susceptible to amikacin (MIC 1,5-6,2 mkg/ml butwere resistantto doxorubicin (MIC 1000 mkg/ml. Subinhibitory concentrations of this cytostatic (S and j MIC raised the sensitivity of experimental strains to amikacin and differently effected on adhesive activity of passage variants of E.coli.

  18. Folate decorated dual drug loaded nanoparticle: role of curcumin in enhancing therapeutic potential of nutlin-3a by reversing multidrug resistance.

    Directory of Open Access Journals (Sweden)

    Manasi Das

    Full Text Available Retinoblastoma is the most common intraocular tumor in children. Malfunctioning of many signaling pathways regulating cell survival or apoptosis, make the disease more vulnerable. Notably, resistance to chemotherapy mediated by MRP-1, lung-resistance protein (LRP is the most challenging aspect to treat this disease. Presently, much attention has been given to the recently developed anticancer drug nutlin-3a because of its non-genotoxic nature and potency to activate tumor suppressor protein p53. However, being a substrate of multidrug resistance protein MRP1 and Pgp its application has become limited. Currently, research has step towards reversing Multi drug resistance (MDR by using curcumin, however its clinical relevance is restricted by plasma instability and poor bioavailability. In the present investigation we tried to encapsulate nutlin-3a and curcumin in PLGA nanoparticle (NPs surface functionalized with folate to enhance therapeutic potential of nutlin-3a by modulating MDR. We document that curcumin can inhibit the expression of MRP-1 and LRP gene/protein in a concentration dependent manner in Y79 cells. In vitro cellular cytotoxicity, cell cycle analysis and apoptosis studies were done to compare the effectiveness of native drugs (single or combined and single or dual drug loaded nanoparticles (unconjugated/folate conjugated. The result demonstrated an augmented therapeutic efficacy of targeted dual drug loaded NPs (Fol-Nut-Cur-NPs over other formulation. Enhanced expression or down regulation of proapoptotic/antiapoptotic proteins respectively and down-regulation of bcl2 and NFκB gene/protein by Fol-Nut-Cur-NPs substantiate the above findings. This is the first investigation exploring the role of curcumin as MDR modulator to enhance the therapeutic potentiality of nutlin-3a, which may opens new direction for targeting cancer with multidrug resistance phenotype.

  19. Measuring enzymatic HIV-1 susceptibility to two reverse transcriptase inhibitors as a rapid and simple approach to HIV-1 drug-resistance testing.

    Directory of Open Access Journals (Sweden)

    Dieter Hoffmann

    Full Text Available Simple and cost-effective approaches for HIV drug-resistance testing are highly desirable for managing increasingly expanding HIV-1 infected populations who initiate antiretroviral therapy (ART, particularly in resource-limited settings. Non-nucleoside reverse trancriptase inhibitor (NNRTI-based regimens with an NRTI backbone containing lamivudine (3TC or emtricitabine (FTC are preferred first ART regimens. Failure with these drug combinations typically involves the selection of NNRTI- and/or 3TC/FTC-resistant viruses. Therefore, the availability of simple assays to measure both types of drug resistance is critical. We have developed a high throughput screening test for assessing enzymatic resistance of the HIV-1 RT in plasma to 3TC/FTC and NNRTIs. The test uses the sensitive "Amp-RT" assay with a newly-developed real-time PCR format to screen biochemically for drug resistance in single reactions containing either 3TC-triphosphate (3TC-TP or nevirapine (NVP. Assay cut-offs were defined based on testing a large panel of subtype B and non-subtype B clinical samples with known genotypic profiles. Enzymatic 3TC resistance correlated well with the presence of M184I/V, and reduced NVP susceptibility was strongly associated with the presence of K103N, Y181C/I, Y188L, and G190A/Q. The sensitivity and specificity for detecting resistance were 97.0% and 96.0% in samples with M184V, and 97.4% and 96.2% for samples with NNRTI mutations, respectively. We further demonstrate the utility of an HIV capture method in plasma by using magnetic beads coated with CD44 antibody that eliminates the need for ultracentifugation. Thus our results support the use of this simple approach for distinguishing WT from NNRTI- or 3TC/FTC-resistant viruses in clinical samples. This enzymatic testing is subtype-independent and can assist in the clinical management of diverse populations particularly in resource-limited settings.

  20. Cross-sectional study of virological failure and multinucleoside reverse transcriptase inhibitor resistance at 12 months of antiretroviral therapy in Western India.

    Science.gov (United States)

    Karade, Santosh K; Ghate, Manisha V; Chaturbhuj, Devidas N; Kadam, Dileep B; Shankar, Subramanian; Gaikwad, Nitin; Gurav, Shraddha; Joshi, Rajneesh; Sane, Suvarna S; Kulkarni, Smita S; Kurle, Swarali N; Paranjape, Ramesh S; Rewari, Bharat B; Gangakhedkar, Raman R

    2016-09-01

    The free antiretroviral therapy (ART) program in India has scaled up to register second largest number of people living with HIV/AIDS across the globe. To assess the effectiveness of current first-line regimen we estimated virological suppression on completion of 1 year of ART. The study describes the correlates of virological failure (VF) and multinucleoside reverse transcriptase inhibitor (NRTI) drug resistance mutations (DRMs).In this cross-sectional study conducted between June and August 2014, consecutive adults from 4 State sponsored ART clinics of western India were recruited for plasma viral load screening at 12 ± 2 months of ART initiation. Individuals with plasma viral load >1000 copies/mL were selected for HIV drug resistance (HIVDR) genotyping. Logistic regression analyses were performed to assess factors associated with VF and multi-NRTI resistance mutations. Criteria adopted for multi-NRTI resistance mutation were either presence of K65R or 3 or more thymidine analog mutations (TAMs) or presence of M184V along with 2 TAMs.Of the 844 study participants, virological suppression at 1 year was achieved in 87.7% of individuals. Factors significantly associated with VF (P reverse transcriptase inhibitor (NNRTI) DRM (78.75%) were higher as compared to NRTI (58.75%). Multi-NRTI DRMs were present in 32.5% of sequences and were significantly associated with CD4 count of ≤100 cells/μL at baseline (adjusted OR -13.00) and TDF-based failing regimen (adjusted OR -20.43). Additionally, low reported adherence was negatively associated with multi-NRTI resistance (adjusted OR -0.11, P = 0.015). K65R mutation was significantly associated with tenofovir (TDF)-based failing regimen (P < 0.001).The study supports early linkage of HIV-infected individuals to the program for ART initiation, adherence improvement, and introduction of viral load monitoring. With recent introduction of TDF-based regimen, the emergence of K65R needs to be monitored closely

  1. Doxorubicin plus paclitaxel in advanced breast cancer

    DEFF Research Database (Denmark)

    Dombernowsky, P; Boesgaard, M; Andersen, E

    1997-01-01

    . As of February 1997, 34 patients have been enrolled, two patients are too early to evaluate, and 13 are continuing treatment. The preliminary response rate is 69% (95% confidence interval, 50% to 84%), ranging from 60% to 80% within the three schedules. The main toxicities consisted of grade 3/4 neutropenia...... in 65% of all courses, with febrile neutropenia in 2%. Stomatitis and paresthesia were rare. To date, eight of 32 patients have developed abnormal left ventricular ejection fraction values and one patient has developed congestive heart failure. Our preliminary conclusions are that bolus doxorubicin...

  2. Molecular Effects of Doxorubicin on Choline Metabolism in Breast Cancer

    Directory of Open Access Journals (Sweden)

    Menglin Cheng

    2017-08-01

    Full Text Available Abnormal choline phospholipid metabolism is a hallmark of cancer. The magnetic resonance spectroscopy (MRS detected total choline (tCho signal can serve as an early noninvasive imaging biomarker of chemotherapy response in breast cancer. We have quantified the individual components of the tCho signal, glycerophosphocholine (GPC, phosphocholine (PC and free choline (Cho, before and after treatment with the commonly used chemotherapeutic drug doxorubicin in weakly metastatic human MCF7 and triple-negative human MDA-MB-231 breast cancer cells. While the tCho concentration did not change following doxorubicin treatment, GPC significantly increased and PC decreased. Of the two phosphatidylcholine-specific PLD enzymes, only PLD1, but not PLD2, mRNA was down-regulated by doxorubicin treatment. For the two reported genes encoding GPC phosphodiesterase, the mRNA of GDPD6, but not GDPD5, decreased following doxorubicin treatment. mRNA levels of choline kinase α (ChKα, which converts Cho to PC, were reduced following doxorubicin treatment. PLD1 and ChKα protein levels decreased following doxorubicin treatment in a concentration dependent manner. Treatment with the PLD1 specific inhibitor VU0155069 sensitized MCF7 and MDA-MB-231 breast cancer cells to doxorubicin-induced cytotoxicity. Low concentrations of 100 nM of doxorubicin increased MDA-MB-231 cell migration. GDPD6, but not PLD1 or ChKα, silencing by siRNA abolished doxorubicin-induced breast cancer cell migration. Doxorubicin induced GPC increase and PC decrease are caused by reductions in PLD1, GDPD6, and ChKα mRNA and protein expression. We have shown that silencing or inhibiting these genes/proteins can promote drug effectiveness and reduce adverse drug effects. Our findings emphasize the importance of detecting PC and GPC individually.

  3. Structure of the HIV-1 reverse transcriptase Q151M mutant: insights into the inhibitor resistance of HIV-1 reverse transcriptase and the structure of the nucleotide-binding pocket of Hepatitis B virus polymerase

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Akiyoshi; Tamura, Noriko; Yasutake, Yoshiaki, E-mail: y-yasutake@aist.go.jp [National Institute of Advanced Industrial Science and Technology (AIST), 2-17-2-1 Tsukisamu-Higashi, Toyohira, Sapporo, Hokkaido 062-8517 (Japan)

    2015-10-23

    The structure of the HIV-1 reverse transcriptase Q151M mutant was determined at a resolution of 2.6 Å in space group P321. Hepatitis B virus polymerase (HBV Pol) is an important target for anti-HBV drug development; however, its low solubility and stability in vitro has hindered detailed structural studies. Certain nucleotide reverse transcriptase (RT) inhibitors (NRTIs) such as tenofovir and lamivudine can inhibit both HBV Pol and Human immunodeficiency virus 1 (HIV-1) RT, leading to speculation on structural and mechanistic analogies between the deoxynucleotide triphosphate (dNTP)-binding sites of these enzymes. The Q151M mutation in HIV-1 RT, located at the dNTP-binding site, confers resistance to various NRTIs, while maintaining sensitivity to tenofovir and lamivudine. The residue corresponding to Gln151 is strictly conserved as a methionine in HBV Pol. Therefore, the structure of the dNTP-binding pocket of the HIV-1 RT Q151M mutant may reflect that of HBV Pol. Here, the crystal structure of HIV-1 RT Q151M, determined at 2.6 Å resolution, in a new crystal form with space group P321 is presented. Although the structure of HIV-1 RT Q151M superimposes well onto that of HIV-1 RT in a closed conformation, a slight movement of the β-strands (β2–β3) that partially create the dNTP-binding pocket was observed. This movement might be caused by the introduction of the bulky thioether group of Met151. The structure also highlighted the possibility that the hydrogen-bonding network among amino acids and NRTIs is rearranged by the Q151M mutation, leading to a difference in the affinity of NRTIs for HIV-1 RT and HBV Pol.

  4. Expression of Multidrug Resistance Genes in Peripheral Blood of Patients with Refractory Epilepsy and the Reverse Effect of Oxcarbazepine on Its Expression.

    Science.gov (United States)

    Ji, Jinming; Li, Gang; Ma, Yunxia; Pan, Shuangshuang; Yuan, Rongrong

    2018-01-01

    We aimed to investigate the expression levels of multidrug resistance gene 1 (MDR1), multidrug resistance-associated protein 1 (MRP1) and multidrug resistance P-glycoprotein (P-gp) in peripheral blood of patients with refractory epilepsy. Patients with epilepsy (n=24) and those with refractory epilepsy (n=24) were selected, and 30 normal volunteers were enrolled as control. The expression level of MDR1 genes was detected using semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). The expression levels of P-gp and MRP1 were detected via Western blotting. The above-mentioned patients with refractory epilepsy were randomly divided into the oxcarbazepine group (OB group) and placebo group (OZ group). After consecutive 8-week oral administration of drugs, the curative effect and adverse reactions of patients with refractory epilepsy were observed, and the life quality of patients was evaluated. The expression levels of MDR1 genes, P-gp and MRP1 in peripheral blood of patients with refractory epilepsy were significantly increased compared with those of patients with epilepsy, ( P refractory epilepsy. The mechanism may be related to MDR1, MRP1 and Pgp expression.

  5. Resistance of the constitutive microflora of biofilms formed on whey reverse-osmosis membranes to individual cleaning steps of a typical clean-in-place protocol.

    Science.gov (United States)

    Anand, Sanjeev; Singh, Diwakar

    2013-10-01

    This experiment evaluates the effectiveness of individual steps of a clean-in-place protocol against the biofilm constitutive microflora isolated from the biofilms developed on whey reverse-osmosis membranes, aged 2 to 14 mo, under industrial processing conditions. The isolates used for the in vitro resistance studies included species of Bacillus, Enterococcus, Streptococcus, Staphylococcus, Micrococcus, Aeromonas, Corynebacterium, Pseudomonas, Klebsiella, and Escherichia. The 6 cleaning steps (alkali, surfactant, acid, enzyme, a second surfactant, and sanitizer treatment) revealed resistance of isolates in both planktonic and biofilm-embedded cell states. The most effective step was the acid treatment, which resulted in 4.54 to 7.90 and 2.09 to 5.02 log reductions of the planktonic and biofilm-embedded cells, respectively. Although the sanitizer step causing a reduction of 4.91 to 8.33 log in the case of planktonic cells, it was less effective against the biofilm-embedded cells, resulting in a reduction of 0.59 to 1.64 log. Bacillus spp. showed the highest resistance in both planktonic, as well as embedded cell states. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  6. Phenotypic mechanism of HIV-1 resistance to 3'-azido-3'-deoxythymidine (AZT): increased polymerization processivity and enhanced sensitivity to pyrophosphate of the mutant viral reverse transcriptase.

    Science.gov (United States)

    Arion, D; Kaushik, N; McCormick, S; Borkow, G; Parniak, M A

    1998-11-10

    The multiple mutations associated with high-level AZT resistance (D67N, K70R, T215F, K219Q) arise in two separate subdomains of the viral reverse transcriptase (RT), suggesting that these mutations may contribute differently to overall resistance. We compared wild-type RT with the D67N/K70R/T215F/K219Q, D67N/K70R, and T215F/K219Q mutant enzymes. The D67N/K70R/T215F/K219Q mutant showed increased DNA polymerase processivity; this resulted from decreased template/primer dissociation from RT, and was due to the T215F/K219Q mutations. The D67N/K70R/T215F/K219Q mutant was less sensitive to AZTTP (IC50 approximately 300 nM) than wt RT (IC50 approximately 100 nM) in the presence of 0.5 mM pyrophosphate. This change in pyrophosphate-mediated sensitivity of the mutant enzyme was selective for AZTTP, since similar Km values for TTP and inhibition by ddCTP and ddGTP were noted with wt and mutant RT in the absence or in the presence of pyrophosphate. The D67N/K70R/T215F/K219Q mutant showed an increased rate of pyrophosphorolysis (the reverse reaction of DNA synthesis) of chain-terminated DNA; this enhanced pyrophosphorolysis was due to the D67N/K70R mutations. However, the processivity of pyrophosphorolysis was similar for the wild-type and mutant enzymes. We propose that HIV-1 resistance to AZT results from the selectively decreased binding of AZTTP and the increased pyrophosphorolytic cleavage of chain-terminated viral DNA by the mutant RT at physiological pyrophosphate levels, resulting in a net decrease in chain termination. The increased processivity of viral DNA synthesis may be important to enable facile HIV replication in the presence of AZT, by compensating for the increased reverse reaction rate.

  7. Tetrathiomolybdate sensitizes ovarian cancer cells to anticancer drugs doxorubicin, fenretinide, 5-fluorouracil and mitomycin C

    Directory of Open Access Journals (Sweden)

    Kim Kyu Kwang

    2012-04-01

    Full Text Available Abstract Background Our recent study showed that tetrathiomolybdate (TM, a drug to treat copper overload disorders, can sensitize drug-resistant endometrial cancer cells to reactive oxygen species (ROS-generating anticancer drug doxorubicin. To expand these findings in the present study we explore TM efficacy in combination with a spectrum of ROS-generating anticancer drugs including mitomycin C, fenretinide, 5-fluorouracil and doxorubicin in ovarian cancer cells as a model system. Methods The effects of TM alone or in combination with doxorubicin, mitomycin C, fenretinide, or 5-fluorouracil were evaluated using a sulforhodamine B assay. Flow cytometry was used to detect the induction of apoptosis and ROS generation. Immunoblot analysis was carried out to investigate changes in signaling pathways. Results TM potentiated doxorubicin-induced cytotoxicity and modulated key regulators of apoptosis (PARP, caspases, JNK and p38 MAPK in SKOV-3 and A2780 ovarian cancer cell lines. These effects were linked to the increased production of ROS, as shown in SKOV-3 cells. ROS scavenging by ascorbic acid blocked the sensitization of cells by TM. TM also sensitized SKOV-3 to mitomycin C, fenretinide, and 5-fluorouracil. The increased cytotoxicity of these drugs in combination with TM was correlated with the activity of ROS, loss of a pro-survival factor (e.g. XIAP and the appearance of a pro-apoptotic marker (e.g. PARP cleavage. Conclusions Our data show that TM increases the efficacy of various anticancer drugs in ovarian cancer cells in a ROS-dependent manner.

  8. Natural lignans from Arctium lappa modulate P-glycoprotein efflux function in multidrug resistant cancer cells.

    Science.gov (United States)

    Su, Shan; Cheng, Xinlai; Wink, Michael

    2015-02-15

    Arctium lappa is a well-known traditional medicinal plant in China (TCM) and Europe that has been used for thousands of years to treat arthritis, baldness or cancer. The plant produces lignans as secondary metabolites which have a wide range of bioactivities. Yet, their ability to reverse multidrug resistance (MDR) in cancer cells has not been explored. In this study, we isolated six lignans from A. lappa seeds, namely arctigenin, matairesinol, arctiin, (iso)lappaol A, lappaol C, and lappaol F. The MDR reversal potential of the isolated lignans and the underlying mechanism of action were studied using two MDR cancer cell lines, CaCo2 and CEM/ADR 5000 which overexpress P-gp and other ABC transporters. In two-drug combinations of lignans with the cytotoxic doxorubicin, all lignans exhibited synergistic effects in CaCo2 cells and matairesinol, arctiin, lappaol C and lappaol F display synergistic activity in CEM/ADR 5000 cells. Additionally, in three-drug combinations of lignans with the saponin digitonin and doxorubicin MDR reversal activity was even stronger enhanced. The lignans can increase the retention of the P-gp substrate rhodamine 123 in CEM/ADR 5000 cells, indicating that lignans can inhibit the activity of P-gp. Our study provides a first insight into the potential chemosensitizing activity of a series of natural lignans, which might be candidates for developing novel adjuvant anticancer agents. Copyright © 2015 Elsevier GmbH. All rights reserved.

  9. Biopolymer based nanosystem for doxorubicin targeted delivery.

    Science.gov (United States)

    Csikós, Zsuzsanna; Kerekes, Krisztina; Fazekas, Erika; Kun, Sándor; Borbély, János

    2017-01-01

    This study describes formation of an actively and passively targeted, water-soluble drug delivery system (DDS) which contains doxorubicin (DOX). The system comprises two biocompatible and biodegradable polymers: poly-γ-glutamic acid (PGA) and chitosan (CH). Self-assembly of these biopolymers in aqueous medium results stable nanoparticles (NPs) with a hydrodynamic size of 80-150 nm and slightly negative surface charge. Folic acid (FA) was used as targeting agent bonded to the polyanion (PA) and also to the surface of the NPs. The NP's physical stability, active targeting effect, cellular toxicity, release profile and in vivo anti-tumor efficacy were investigated. It was found that the targeted, self-assembled nanoparticles are stable at 4°C for several months, cause better in vitro toxicity effect on folate receptor (FR) positive cell lines than the doxorubicin or the non-targeted nanosystem and based on its release profile it is expected, that the nanosystem will remain stable during the circulation in the body. Pharmacodynamic studies demonstrated that the DOX-loaded nanoparticles can deliver greater tumor growth inhibition than the free drug molecules and the liposomal compound, with less general toxicity. It was observed that the overall survival is the main benefit of the biopolymer based drug delivery system.

  10. Studies on the response of resistive-wall modes to applied magnetic perturbations in the EXTRAP T2R reversed field pinch

    Science.gov (United States)

    Gregoratto, D.; Drake, J. R.; Yadikin, D.; Liu, Y. Q.; Paccagnella, R.; Brunsell, P. R.; Bolzonella, T.; Marchiori, G.; Cecconello, M.

    2005-09-01

    Arrays of magnetic coils and sensors in the EXTRAP T2R [P. R. Brunsell et al., Plasma Phys. Controlled Fusion 43 1457 (2001)] reversed-field pinch have been used to investigate the plasma response to an applied resonant magnetic perturbation in the range of the resistive-wall modes (RWMs). Measured RWM growth rates agree with predictions of a cylindrical ideal-plasma model. The linear growth of low-n marginally stable RWMs is related to the so-called resonant-field amplification due to a dominant ∣n∣=2 machine error field of about 2 G. The dynamics of the m =1 RWMs interacting with the applied field produced by the coils can be accurately described by a two-pole system. Estimated poles and residues are given with sufficient accuracy by the cylindrical model with a thin continuous wall.

  11. Potent cross-reactive immune response against the wild-type and drug-resistant forms of HIV reverse transcriptase after the chimeric gene immunization.

    Science.gov (United States)

    Starodubova, Elizaveta; Boberg, Andreas; Ivanov, Alexander; Latyshev, Oleg; Petrakova, Natalia; Kuzmenko, Yulia; Litvina, Marina; Chernousov, Alexander; Kochetkov, Sergey; Karpov, Vadim; Wahren, Britta; Isaguliants, Maria G

    2010-02-23

    HIV reverse transcriptase (RT) can be considered as a target and an instrument of immunotherapy aimed at limiting the emergence and spread of drug-resistant HIV. The chimeric genes coding for the wild-type and multi-drug-resistant RT (RT1.14) fused to lysosome-associated membrane protein 1 (LAMP-1) were injected intramuscularly into BALB/c mice. The immune response was assessed by ELISpot, cytokine ELISA intracellular IFN-gamma staining, and antibody ELISA. The genes for RT- and RT1.14-LAMP fusions (RT-LAMP and RT1.14-LAMP) were immunogenic generating a mixed Th1/Th2-profile of immune response, while the wild-type RT gene induced only weak immune response. Specific secretion of Th1-cytokines increased with increasing level of RT modification: RTresistance mutations and their wild-type variants. Gene immunization induced specific IgG (10(3)), and transient serum IgA (10(2)). Low immunogenicity of the parental RT may be explained by tolerance to the enzyme that is a common endogenous retroviral antigen. Potent immune recognition of RT after immunization with chimeric RT genes indicates that this tolerance could be overcome. Immunization with mutant HIV genes may represent an immunotherapeutical supplement to antiretroviral treatment preventing the emergence of drug resistance. Copyright 2009 Elsevier Ltd. All rights reserved.

  12. Chronic caffeine intake reverses age-induced insulin resistance in the rat: effect on skeletal muscle Glut4 transporters and AMPK activity.

    Science.gov (United States)

    Guarino, Maria P; Ribeiro, Maria J; Sacramento, Joana F; Conde, Sílvia V

    2013-10-01

    The role of caffeine consumption on insulin action is still under debate. The hypothesis that chronic caffeine intake reverses aging-induced insulin resistance in the rat was tested in this work. The mechanism by which caffeine restores insulin sensitivity was also investigated. Six groups of rats were used: 3 months old (3 M), 3 months old caffeine-treated (3MCaf), 12 months old (12 M), 12 months old caffeine-treated (12MCaf), 24 months old (24 M), and 24 months old caffeine-treated (24MCaf). Caffeine was administered in drinking water (1 g/l) during 15 days. Insulin sensitivity was assessed by means of the insulin tolerance test. Blood pressure, body weight, visceral and total fat, fasting glycemia and insulinemia, plasma nonesterified fatty acids (NEFA), total antioxidant capacity (TAC), cortisol, nitric oxide, and catecholamines were monitored. Skeletal muscle Glut4 and 5'-AMP activated protein kinase (AMPK) protein expression and activity were also assessed. Aged rats exhibited diminished insulin sensitivity accompanied by hyperinsulinemia and normoglycemia, increased visceral and total fat, decreased TAC and plasma catecholamines, and also decreased skeletal muscle Glut4 and AMPK protein expression. Chronic caffeine intake restored insulin sensitivity and regularized circulating insulin and NEFA in both aging models. Caffeine neither modified skeletal muscle AMPK expression nor activity in aged rats; however, it decreased visceral and total fat in 12 M rats and it restored skeletal muscle Glut4 expression to control values in 24 M rats. We concluded that chronic caffeine intake reverses aging-induced insulin resistance in rats by decreasing NEFA production and also by increasing Glut4 expression in skeletal muscle.

  13. Glucosylceramide synthase upregulates MDR1 expression in the regulation of cancer drug resistance through cSrc and β-catenin signaling

    Directory of Open Access Journals (Sweden)

    Cabot Myles C

    2010-06-01

    Full Text Available Abstract Background Drug resistance is the outcome of multiple-gene interactions in cancer cells under stress of anticancer agents. MDR1 overexpression is most commonly detected in drug-resistant cancers and accompanied with other gene alterations including enhanced glucosylceramide synthase (GCS. MDR1 encodes for P-glycoprotein that extrudes anticancer drugs. Polymorphisms of MDR1 disrupt the effects of P-glycoprotein antagonists and limit the success of drug resistance reversal in clinical trials. GCS converts ceramide to glucosylceramide, reducing the impact of ceramide-induced apoptosis and increasing glycosphingolipid (GSL synthesis. Understanding the molecular mechanisms underlying MDR1 overexpression and how it interacts with GCS may find effective approaches to reverse drug resistance. Results MDR1 and GCS were coincidently overexpressed in drug-resistant breast, ovary, cervical and colon cancer cells; silencing GCS using a novel mixed-backbone oligonucleotide (MBO-asGCS sensitized these four drug-resistant cell lines to doxorubicin. This sensitization was correlated with the decreased MDR1 expression and the increased doxorubicin accumulation. Doxorubicin treatment induced GCS and MDR1 expression in tumors, but MBO-asGCS treatment eliminated "in-vivo" growth of drug-resistant tumor (NCI/ADR-RES. MBO-asGCS suppressed the expression of MDR1 with GCS and sensitized NCI/ADR-RES tumor to doxorubicin. The expression of P-glycoprotein and the function of its drug efflux of tumors were decreased by 4 and 8 times after MBO-asGCS treatment, even though this treatment did not have a significant effect on P-glycoprotein in normal small intestine. GCS transient transfection induced MDR1 overexpression and increased P-glycoprotein efflux in dose-dependent fashion in OVCAR-8 cancer cells. GSL profiling, silencing of globotriaosylceramide synthase and assessment of signaling pathway indicated that GCS transfection significantly increased globo series

  14. Fbxw7-associated drug resistance is reversed by induction of terminal differentiation in murine intestinal organoid culture

    Directory of Open Access Journals (Sweden)

    Federica Lorenzi

    2016-01-01

    Full Text Available Colorectal cancer (CRC is one of the top three cancer-related causes of death worldwide. FBXW7 is a known tumor-suppressor gene, commonly mutated in CRC and in a variety of other epithelial tumors. Low expression of FBXW7 is also associated with poor prognosis. Loss of FBXW7 sensitizes cancer cells to certain drugs, while making them more resistant to other types of chemotherapies. However, is not fully understood how epithelial cells within normal gut and primary tumors respond to potential cancer therapeutics. We have studied genetically engineered mice in which the fbxw7 gene is conditionally knocked-out in the intestine (fbxw7ΔG. To further investigate the mechanism of Fbxw7-action, we grew intestinal crypts from floxed-fbxw7 (fbxw7fl/fl and fbxw7ΔG mice, in a Matrigel-based organoid (mini-gut culture. The fbxw7ΔG organoids exhibited rapid budding events in the crypt region. Furthermore, to test organoids for drug response, we exposed day 3 intestinal organoids from fbxw7fl/fl and fbxw7ΔG mice, to various concentrations of 5-fluorouracil (5-FU for 72 hours. 5-FU triggers phenotypic differences in organoids including changing shape, survival, resistance, and death. 5-FU however, rescues the drug-resistance phenotype of fbxw7ΔG through the induction of terminal differentiation. Our results support the hypothesis that a differentiating therapy successfully targets FBXW7-mutated CRC cells.

  15. The pan-PI3K inhibitor GDC-0941 activates canonical WNT signaling to confer resistance in TNBC cells: resistance reversal with WNT inhibitor.

    Science.gov (United States)

    Tzeng, Huey-En; Yang, Lixin; Chen, Kemin; Wang, Yafan; Liu, Yun-Ru; Pan, Shiow-Lin; Gaur, Shikha; Hu, Shuya; Yen, Yun

    2015-05-10

    The pan-PI3K inhibitors are one treatment option for triple-negative breast cancer (TNBC). However, this treatment is ineffective for unknown reasons. Here, we report that aberrant expression of wingless-type MMTV integration site family (WNT) and activated WNT signals, which crosstalk with the PI3K-AKT-mTOR signaling pathway through GSK3β, plays the most critical role in resistance to pan-PI3K inhibitors in TNBC cells. GDC-0941 is a pan-PI3K inhibitor that activates the WNT/beta-catenin pathway in TNBC cells through stimulation of WNT secretion. GDC-0941-triggered WNT/beta-catenin pathway activation was observed in MDA-MB-231 and HCC1937 cells, which are TNBC cell lines showing aberrant WNT/beta-catenin activation, and not in SKBR3 and MCF7 cells. This observation is further investigated in vivo. GDC-0941 exhibited minimal tumor inhibition in MDA-MB-231 cells, but it significantly suppressed tumor growth in HER-positive SK-BR3 cells. In vivo mechanism study revealed the activation of WNT/beta-catenin pathway by GDC-0941. A synergistic effect was observed when combined treatment with GDC-0941 and the WNT inhibitor LGK974 at low concentrations in MDA-MB-231 cells. These findings indicated that WNT pathway activation conferred resistance in TNBC cells treated with GDC-0941. This resistance may be further circumvented through combined treatment with pan-PI3K and WNT inhibitors. Future clinical trials of these two inhibitors are warranted.

  16. MC70 potentiates doxorubicin efficacy in colon and breast cancer in vitro treatment.

    Science.gov (United States)

    Azzariti, Amalia; Quatrale, Anna E; Porcelli, Letizia; Colabufo, Nicola A; Cantore, Mariangela; Cassano, Giuseppe; Gasparre, Giuseppe; Iannelli, Giuseppina; Tommasi, Stefania; Panaro, Maria A; Paradiso, Angelo

    2011-11-16

    A major limitation of cancer treatment is the ability of cancer cells to develop resistance to chemotherapeutic drugs, by the establishment of multidrug resistance. Here, we characterize MC70 as ABC transporters inhibitor and anticancer agent, alone or with chemotherapy. MC70 was analyzed for its interaction with ABCB1, ABCG2 and ABCC1 by specific transport assays. In breast and colon cancer cell lines, cell growth and apoptosis were measured by MTT assay and DNA laddering Elisa kit, respectively. Cell cycle perturbation and cellular targets modulation were analyzed by Flow-cytometry and Western blotting, respectively. MC70 interacted with ABC transporters. In breast cancer cells, MC70 slightly inhibited cell proliferation strongly enhancing doxorubicin effectiveness. By contrast, MC70 was found to inhibit cell growth in colon cancer cells without affecting doxorubicin efficacy and in combination with topoisomerase I inhibitors it could be a promising therapeutic approach. What is more, it was also observed that MC70 induced apoptosis, canceled in favor of necrosis when given in combination with high doses of doxorubicin. MC70 inhibited cell migration probably through its interaction with sigma-1 receptor. Modulations of i) cell cycle, ii) pAkt and the phosphorylation of the three MAPKs were highlighted, while any activity was excluded at transcription level, thus accounting for the phenotypic effects observed. MC70 might be considered as a new potential anticancer agent capable to i) enhance chemotherapy effectiveness and ii) to play a contributory role in the treatment of chemotherapy resistant tumors. Copyright © 2011 Elsevier B.V. All rights reserved.

  17. Fluorescence properties of doxorubicin in PBS buffer and PVA films.

    Science.gov (United States)

    Shah, Sunil; Chandra, Anjali; Kaur, Amanjot; Sabnis, Nirupama; Lacko, Andras; Gryczynski, Zygmunt; Fudala, Rafal; Gryczynski, Ignacy

    2017-05-01

    We studied steady-state and time-resolved fluorescence properties of an anticancer drug Doxorubicin in a saline buffer and poly-vinyl alcohol (PVA) film. Absorption of Doxorubicin, located at blue-green spectral region, allows a convenient excitation with visible light emitting diodes or laser diodes. Emission of Doxorubicin with maximum near 600nm can be easily detected with photomultipliers and CCD cameras. Both, absorption and fluorescence spectra in polymeric matrix show more pronounced vibronic structures than in solution. Also, the steady-state anisotropy in the polymer film is significantly higher than in the saline solution. In PVA film the fluorescence anisotropy is about 0.30 whereas in the saline buffer only 0.07. Quantum efficiencies of Doxorubicin were compared to a known standard Rhodamine 101 which has fluorescence emission in a similar spectral region. The quantum yield of Doxorubicin in PVA film is more than 10% and about twice higher than in the saline solution. Similarly, the lifetime of doxorubicin in PVA film is about 2ns whereas in the saline solution only about 1ns. The fluorescence anisotropy decays show that Doxorubicin molecules are freely rotating in the saline buffer with a correlation time of about 290ps, and are almost completely immobilized in the PVA film. The spectroscopic investigations presented in this manuscript are important, as they provide answers to changes in molecular properties of Doxorubicin depending changes in the local environment, which is useful when synthesizing nanoparticles for Doxorubicin entrapment. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Arsenic trioxide in the mechanism of drug resistance reversal in MCF-7/ADM cell line of human breast cancer.

    Science.gov (United States)

    Wang, Xiuli; Kong, Li; Zhao, Jinyao; Yang, Peiman

    2002-07-01

    To investigate the effect of drug resistance by arsenic trioxide (As(2)O(3)) and its possible mechanism in human breast cancer cell line MCF-7/ADM. Cytotoxicity of As(2)O(3) and the sensibility to adriamycin (ADM) in MCF-7/ADM cell line, a ADM-resistance cell line of human breast cancer, were studied through MTT assay. The concentration of intracellular ADM was detected by spectrofluorometry. With MCF-7/ADM cells treated with As(2)O(3) in combination with ADM, the glutathione-s-transferase (GST) activity was measured by biochemical method. The expression of GST-pi mRNA was assessed by RT-PCR. The non-cytotoxic dose of As(2)O(3) was 0.2 micro mol/L and the low cytotoxic dose was 0.8 micro mol/L to MCF-7/ADM cell line. 0.2 micro mol/L As(2)O(3) could significantly increase the intracellular accumulation of ADM in MCF-7/ADM cell line (P breast cancer, which may be related to the variation of GST-pi enzyme.

  19. A phase II study of gefitinib for patients with advanced HER-1 expressing synovial sarcoma refractory to doxorubicin-containing regimens

    NARCIS (Netherlands)

    I. Ray-Coquard (Isabelle); A. le Cesne (Axel); J.S. Whelan (Jeremy); P. Schöffski (Patrick); B.N. Bui (Binh); J. Verweij (Jaap); S. Marreaud (Sandrine); M.M.B. van Glabbeke (Martine); P.C.W. Hogendoorn (Pancras); J-Y. Blay (Jean Yves)

    2008-01-01

    textabstractRationale. Advanced synovial sarcomas (SyS) refractory to doxorubicin and ifosfamide are highly resistant to the currently available cytotoxic agents. Based on a report showing a specific overexpression of HER-1 in SyS, we investigated an HER-1 inhibitor, gefitinib, in refractory SyS.

  20. Bufalin Reverses HGF-Induced Resistance to EGFR-TKIs in EGFR Mutant Lung Cancer Cells via Blockage of Met/PI3k/Akt Pathway and Induction of Apoptosis

    Directory of Open Access Journals (Sweden)

    Xiao-Hong Kang

    2013-01-01

    Full Text Available The epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs, such as gefitinib and erlotinib, have shown promising therapeutic efficacy in nonsmall cell lung cancer (NSCLC patients harboring epidermal growth factor receptor- (EGFR- activating mutation. However, the inevitable recurrence resulting from acquired resistance has limited the clinical improvement in therapy outcomes. Many studies demonstrate that hepatocyte growth factor- (HGF- Met axis plays an important role in tumor progression and drug sensitivity. HGF may induce resistance to EGFR-TKIs in EGFR mutant lung cancer cells by Met/PI3K/Akt signaling. The purpose of this study was to determine whether bufalin, a major bioactive component of Venenum Bufonis, could reverse HGF-induced resistance to reversible and irreversible EGFR-TKIs in mutant lung cancer cells PC-9, HCC827, and H1975. Our studies showed that bufalin could reverse resistance to reversible and irreversible EGFR-TKIs induced by exogenous HGF in EGFR mutant lung cancer cells by inhibiting the Met/PI3K/Akt pathway and inducing death signaling. These results suggested that bufalin might have a potential to overcome HGF-induced resistance to molecular-targeted drugs for lung cancer.

  1. Hericium erinaceus enhances doxorubicin-induced apoptosis in human hepatocellular carcinoma cells.

    Science.gov (United States)

    Lee, Jong Seok; Hong, Eock Kee

    2010-11-28

    It has been demonstrated that the Hericium erinaceus (HE) mushroom, which primarily consists of polysaccharides, possesses anti-tumor activities. However, the mechanisms by which HE inhibits human hepatocellular carcinoma growth remain unknown. Our study demonstrates that HE acts as an enhancer to sensitize doxorubicin (Dox)-mediated apoptotic signaling, and this sensitization can be achieved by reducing c-FLIP expression via JNK activation and enhancing intracellular Dox accumulation via the inhibition of NF-κB activity. These findings suggest that HE in combination with Dox serves as an effective tool for treating drug-resistant human hepatocellular carcinoma. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  2. Exploiting drug-resistant enzymes as tools to identify thienopyrimidinone inhibitors of human immunodeficiency virus reverse transcriptase-associated ribonuclease H.

    Science.gov (United States)

    Masaoka, Takashi; Chung, Suhman; Caboni, Pierluigi; Rausch, Jason W; Wilson, Jennifer A; Taskent-Sezgin, Humeyra; Beutler, John A; Tocco, Graziella; Le Grice, Stuart F J

    2013-07-11

    The thienopyrimidinone 5,6-dimethyl-2-(4-nitrophenyl)thieno[2,3-d]pyrimidin-4(3H)-one (DNTP) occupies the interface between the p66 ribonuclease H (RNase H) domain and p51 thumb of human immunodeficiency virus reverse transcriptase (HIV RT), thereby inducing a conformational change incompatible with catalysis. Here, we combined biochemical characterization of 39 DNTP derivatives with antiviral testing of selected compounds. In addition to wild-type HIV-1 RT, derivatives were evaluated with rationally designed, p66/p51 heterodimers exhibiting high-level DNTP sensitivity or resistance. This strategy identified 3',4'-dihydroxyphenyl (catechol) substituted thienopyrimidinones with submicromolar in vitro activity against both wild type HIV-1 RT and drug-resistant variants. Thermal shift analysis indicates that, in contrast to active site RNase H inhibitors, these thienopyrimidinones destabilize the enzyme, in some instances reducing the Tm by 5 °C. Importantly, catechol-containing thienopyrimidinones also inhibit HIV-1 replication in cells. Our data strengthen the case for allosteric inhibition of HIV RNase H activity, providing a platform for designing improved antagonists for use in combination antiviral therapy.

  3. Formoxanthone C, isolated from Cratoxylum formosum ssp. pruniflorum, reverses anticancer drug resistance by inducing both apoptosis and autophagy in human A549 lung cancer cells.

    Science.gov (United States)

    Kaewpiboon, Chutima; Boonnak, Nawong; Kaowinn, Sirichat; Chung, Young-Hwa

    2018-02-15

    Multidrug resistance (MDR) cancer toward cancer chemotherapy is one of the obstacles in cancer therapy. Therefore, it is of interested to use formoxanthone C (1,3,5,6-tetraoxygenated xanthone; XanX), a natural compound, which showed cytotoxicity against MDR human A549 lung cancer (A549RT-eto). The treatment with XanX induced not only apoptosis- in A549RT-eto cells, but also autophagy-cell death. Inhibition of apoptosis did not block XanX-induced autophagy in A549RT-eto cells. Furthermore, suppression of autophagy by beclin-1 small interfering RNAs (siRNAs) did not interrupt XanX-induced apoptosis, indicating that XanX can separately induce apoptosis and autophagy. Of interest, XanX treatment reduced levels of histone deacetylase 4 (HDAC4) protein overexpressed in A549RT-etocells. The co-treatment with XanX and HDAC4 siRNA accelerated both autophagy and apoptosis more than that by XanX treatment alone, suggesting survival of HDAC4 in A549RT-eto cells. XanX reverses etoposide resistance in A549RT-eto cells by induction of both autophagy and apoptosis, and confers cytotoxicity through down-regulation of HDAC4. Copyright © 2017. Published by Elsevier Ltd.

  4. Selenoesters and selenoanhydrides as novel multidrug resistance reversing agents: A confirmation study in a colon cancer MDR cell line.

    Science.gov (United States)

    Gajdács, Márió; Spengler, Gabriella; Sanmartín, Carmen; Marć, Małgorzata Anna; Handzlik, Jadwiga; Domínguez-Álvarez, Enrique

    2017-02-15

    Taking into account that multidrug resistance (MDR) is the main cause for chemotherapeutic failure in cancer treatment and as a continuation of our efforts to overcome this problem we report the evaluation of one cyclic selenoanhydride (1) and ten selenoesters (2-11) in MDR human colon adenocarcinoma Colo 320 cell line. The most potent derivatives (1, 9-11) inhibited the ABCB1 efflux pump much stronger than the reference compound verapamil. Particularly, the best one (9) was 4-fold more potent than verapamil at a 10-fold lower concentration. Furthermore, the evaluated derivatives exerted a potent and selective cytotoxic activity. In addition, they were strong apoptosis inducers as the four derivatives triggered apoptotic events in a 64-72% of the examined MDR Colo 320 human adenocarcinoma cells. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Reverse Logistics

    OpenAIRE

    Kulikova, Olga

    2016-01-01

    This thesis was focused on the analysis of the concept of reverse logistics and actual reverse processes which are implemented in mining industry and finding solutions for the optimization of reverse logistics in this sphere. The objective of this paper was the assessment of the development of reverse logistics in mining industry on the example of potash production. The theoretical part was based on reverse logistics and mining waste related literature and provided foundations for further...

  6. Drug resistance-related mutations T369V/I in the connection subdomain of HIV-1 reverse transcriptase severely impair viral fitness.

    Science.gov (United States)

    Wang, Zheng; Zhang, Junli; Li, Fan; Ji, Xiaolin; Liao, Lingjie; Ma, Liying; Xing, Hui; Feng, Yi; Li, Dan; Shao, Yiming

    2017-04-02

    Fitness is a key parameter in the measurement of transmission capacity of individual drug-resistant HIV. Drug-resistance related mutations (DRMs) T369V/I and A371V in the connection subdomain (CN) of reverse transcriptase (RT) occur at higher frequencies in the individuals experiencing antiretroviral therapy failure. Here, we evaluated the effects of T369V/I and A371V on viral fitness, in the presence or in the absence of thymidine analogue resistance-associated mutations (TAMs) and assessed the effect of potential RT structure-related mechanism on change in viral fitness. Mutations T369V/I, A371V, alone or in combination with TAMs were introduced into a modified HIV-1 infectious clone AT1 by site-directed mutagenesis. Then, experiments on mutant and wild-type virus AT2 were performed separately using a growth-competition assay, and then the relative fitness was calculated. Structural analysis of RT was conducted using Pymol software. Results showed that T369V/I severely impaired the relative virus fitness, and A371V compensated for the viral fitness reduction caused by TAMs. Structural modeling of RT suggests that T369V/I substitutions disrupt powerful hydrogen bonds formed by T369 and V365 in p51 and p66. This study indicates that the secondary DRMs within CN might efficiently damage viral fitness, and provides valuable information for clinical surveillance and prevention of HIV-1 strains carrying these DRMs. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. The rtL229 substitutions in the reverse transcriptase region of hepatitis B virus (HBV) polymerase are potentially associated with lamivudine resistance as a compensatory mutation.

    Science.gov (United States)

    Ji, Dong; Liu, Yan; Li, Le; Xu, Zhihui; Si, Lan-Lan; Dai, Jiu-Zeng; Li, Xiaodong; Wang, Lin; Yao, Zengtao; Xin, Shao-Jie; Chen, Guo-Feng; Xu, Dongping

    2012-05-01

    It remains unclear whether hepatitis B virus (HBV) reverse-transcriptase (RT) rtL229 substitutions influence HBV drug resistance. The study was to investigate the association of HBV rtL229 substitutions with viral resistance to lamivudine (LAM). Entire HBV RT genes were amplified by nested PCR and sequenced from sera of 6000 nucleos(t)ide analog-experienced patients with chronic HBV infection. The incidence and clinic relevance of rtL229 substitutions were analyzed. Replication-competent viral amplicons which harbored HBV genomes of wild-type, rtM204I, or rtM204I in conjunction with various rtL229 substitutions (rtL229F/W/M/V) were constructed. The amplicons were transfected into HepG2 cells for phenotyping of replication capacity and susceptibility to nucleos(t)ide analogs. The rtL229 substitutions were detected in 6.57% (394/6000) of patients. Individual substitution incidences were 2.77%, 0.97%, 0.83% and 0.55% for rtL229V, rtL229F, rtL229M and rtL229W, respectively. The incidence of rtL229 substitutions was significantly higher in LAM-experienced patients (341/4220, 8.1%) than in LAM-naïve patients (53/1780, 3.0%), and were independently associated with genotypic LAM resistance (77.9% vs. 21.2%, OR 8.806, 95%CI 6.345-12.223) and low viral replication (HBV DNA B.V. All rights reserved.

  8. Evaluation of a series of 2-napthamide derivatives as inhibitors of the drug efflux pump AcrB for the reversal of antimicrobial resistance.

    Science.gov (United States)

    Wang, Yinhu; Mowla, Rumana; Guo, Liwei; Ogunniyi, Abiodun D; Rahman, Taufiq; De Barros Lopes, Miguel A; Ma, Shutao; Venter, Henrietta

    2017-02-15

    Drug efflux pumps confer multidrug resistance to dangerous pathogens which makes these pumps important drug targets. We have synthesised a novel series of compounds based on a 2-naphthamide pharmacore aimed at inhibiting the efflux pumps from Gram-negative bacteria. The archeatypical transporter AcrB from Escherichia coli was used as model efflux pump as AcrB is widely conserved throughout Gram-negative organisms. The compounds were tested for their antibacterial action, ability to potentiate the action of antibiotics and for their ability to inhibit Nile Red efflux by AcrB. None of the compounds were antimicrobial against E. coli wild type cells. Most of the compounds were able to inhibit Nile Red efflux indicating that they are substrates of the AcrB efflux pump. Three compounds were able to synergise with antibiotics and reverse resistance in the resistant phenotype. Compound A3, 4-(isopentyloxy)-2-naphthamide, reduced the MICs of erythromycin and chloramphenicol to the MIC levels of the drug sensitive strain that lacks an efflux pump. A3 had no effect on the MIC of the non-substrate rifampicin indicating that this compound acts specifically through the AcrB efflux pump. A3 also does not act through non-specific mechanisms such as outer membrane or inner membrane permeabilisation and is not cytotoxic against mammalian cell lines. Therefore, we have designed and synthesised a novel chemical compound with great potential to further optimisation as inhibitor of drug efflux pumps. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Reversal of Ampicillin Resistance in MRSA via Inhibition of Penicillin-Binding Protein 2a by Acalypha wilkesiana

    Directory of Open Access Journals (Sweden)

    Carolina Santiago

    2014-01-01

    Full Text Available The inhibitory activity of a semipure fraction from the plant, Acalypha wilkesiana assigned as 9EA-FC-B, alone and in combination with ampicillin, was studied against methicillin-resistant Staphylococcus aureus (MRSA. In addition, effects of the combination treatment on PBP2a expression were investigated. Microdilution assay was used to determine the minimal inhibitory concentrations (MIC. Synergistic effects of 9EA-FC-B with ampicillin were determined using the fractional inhibitory concentration (FIC index and kinetic growth curve assay. Western blot experiments were carried out to study the PBP2a expression in treated MRSA cultures. The results showed a synergistic effect between ampicillin and 9EA-FC-B treatment with the lowest FIC index of 0.19 (synergism ≤ 0.5. The presence of 9EA-FC-B reduced the MIC of ampicillin from 50 to 1.56 μg mL−1. When ampicillin and 9EA-FC-B were combined at subinhibitory level, the kinetic growth curves were suppressed. The antibacterial effect of 9EA-FC-B and ampicillin was shown to be synergistic. The synergism is due the ability of 9EA-FC-B to suppress the activity of PBP2a, thus restoring the susceptibility of MRSA to ampicillin. Corilagin was postulated to be the constituent responsible for the synergistic activity showed by 9EA-FC-B.

  10. P-Glycoprotein Mediated Multidrug Resistance Reversal by Phytochemicals: A Review of SAR & Future Perspective for Drug Design.

    Science.gov (United States)

    Syed, Safiulla Basha; Coumar, Mohane Selvaraj

    2016-01-01

    A major impediment for cancer chemotherapy is the development of multidrug-resistance (MDR). Continuous use of chemotherapeutic drugs during cancer therapy induces the expression of PGlycoprotein (P-gp, MDR1), an ATP dependant transporter, which in turn reduces the intracellular accumulation of chemotherapeutic drugs leading to MDR. Extensive research over the years has identified several potential P-gp inhibitors, both synthetic as well as natural origin, to overcome the MDR during cancer chemotherapy. In this review, we discuss the cellular pathways involved and transcription factors regulating the expression of P-gp. A number of phytochemicals are reported to inhibit P-gp activity and MDR1 expression; the structure-activity relationship (SAR) among the phytochemicals for P-gp inhibition and the effect of these phytochemicals on cellular signaling pathways regulating P-gp expression are discussed in detail. Moreover, structural biology and mutagenesis studies on P-gp along with docking studies throw light on the structural requirements for P-gp inhibition. Insight provided in the review about the phytochemicals molecular mechanism and SAR could catalyze the design of potent P-gp inhibitors in the future and could help to overcome MDR in cancer chemotherapy.

  11. Platinum(IV) complexes conjugated with phenstatin analogue as inhibitors of microtubule polymerization and reverser of multidrug resistance.

    Science.gov (United States)

    Huang, Xiaochao; Huang, Rizhen; Gou, Shaohua; Wang, Zhimei; Liao, Zhixin; Wang, Hengshan

    2017-09-01

    Pt(IV) complexes comprising a phenstatin analogue, as dual-targeting Pt(IV) prodrug, were designed and synthesized. They were found not only to carry the DNA binding platinum warhead into the tumor cells, but also to have a small molecular unit to inhibit tubulin polymerization. In vitro evaluation results revealed that Pt(IV) complexes showed better and more potent activity against the test human cancer cells including cisplatin resistant cell lines than their corresponding Pt(II) counterparts. In addition, the Pt(IV) derivative of cisplatin, complex 10, exhibited highly selective inhibition in human cancer cells and displayed no obvious toxicity to two human normal cell lines, respectively. Mechanism study suggested that complex 10 induced cell-cycle arrest at the G2/M phase and caused apoptotic cell death of human lung cancer NCI-H460 cells through the mitochondrial mediated pathway. Moreover, complex 10 effectively inhibited the tumor growth in the NCI-H460 xenograft model. Copyright © 2017. Published by Elsevier Ltd.

  12. The effect of HCV serological status on Doxorubicin based ...

    African Journals Online (AJOL)

    Karim Yousri Welaya

    2014-09-10

    68:1203–9. 15. King PD, Perry MC. Hepatotoxicity of chemotherapy. Oncologist · 2001;6:162–76. 16. Piscitelli SC, Rodvold KA, Rushing DA, Tewksbury DA. Phar- · macokinetics and pharmacodynamics of doxorubicin in ...

  13. Bicontinuous cubic liquid crystalline nanoparticles for oral delivery of Doxorubicin

    DEFF Research Database (Denmark)

    Swarnakar, Nitin K; Thanki, Kaushik; Jain, Sanyog

    2014-01-01

    PURPOSE: The present study explores the potential of bicontinous cubic liquid crystalline nanoparticles (LCNPs) for improving therapeutic potential of doxorubicin. METHODS: Phytantriol based Dox-LCNPs were prepared using hydrotrope method, optimized for various formulation components, process var...

  14. Clinical characteristics of doxorubicin-associated alopecia in 28 dogs.

    Science.gov (United States)

    Falk, Elizabeth F; Lam, Andrea T H; Barber, Lisa G; Ferrer, Lluis

    2017-04-01

    Chemotherapy-induced alopecia (CIA) is common in humans, but there are limited reports describing the clinical features of CIA in dogs. To describe the epidemiological and clinical characteristics of doxorubicin-associated alopecia (DAA) in canine patients at a teaching hospital from 2012 to 2014. Signalment, diagnosis, treatment protocols and clinical examination findings were recorded in 150 dogs treated with doxorubicin from 2012 to 2014. Medical records were searched retrospectively for the keywords "alopecia" and "hypotrichosis." Dogs were excluded if the causal link of hair loss was unclear. Doxorubicin-associated alopecia was reported in 28 of 150 dogs (19%). Two parameters were statistically associated with the development of DAA: coat-type and cumulative doxorubicin dose. Dogs with curly or wire-haired coat-type were significantly more likely to develop DAA than dogs with straight-haired coat-type [χ 2 (1, N = 147) = 30, P < 0.0001]. After adjusting for sex, weight and doxorubicin dose, the odds of dogs with curly or wire-haired coat-type developing DAA were 22 times higher than those with straight-haired coat-type (P < 0.0001). Dogs that developed DAA received a significantly higher median cumulative doxorubicin dose (103.0 versus 84.5 mg/m 2 ; P = 0.0039) than those that did not develop DAA. Dogs treated with doxorubicin may be at risk for developing DAA. This risk increases as the cumulative dose of doxorubicin increases, and with a curly or wire-haired coat-type. © 2016 ESVD and ACVD.

  15. Modeling dynamics of cell-to-cell variability in TRAIL-induced apoptosis explains fractional killing and predicts reversible resistance.

    Directory of Open Access Journals (Sweden)

    François Bertaux

    2014-10-01

    Full Text Available Isogenic cells sensing identical external signals can take markedly different decisions. Such decisions often correlate with pre-existing cell-to-cell differences in protein levels. When not neglected in signal transduction models, these differences are accounted for in a static manner, by assuming randomly distributed initial protein levels. However, this approach ignores the a priori non-trivial interplay between signal transduction and the source of this cell-to-cell variability: temporal fluctuations of protein levels in individual cells, driven by noisy synthesis and degradation. Thus, modeling protein fluctuations, rather than their consequences on the initial population heterogeneity, would set the quantitative analysis of signal transduction on firmer grounds. Adopting this dynamical view on cell-to-cell differences amounts to recast extrinsic variability into intrinsic noise. Here, we propose a generic approach to merge, in a systematic and principled manner, signal transduction models with stochastic protein turnover models. When applied to an established kinetic model of TRAIL-induced apoptosis, our approach markedly increased model prediction capabilities. One obtains a mechanistic explanation of yet-unexplained observations on fractional killing and non-trivial robust predictions of the temporal evolution of cell resistance to TRAIL in HeLa cells. Our results provide an alternative explanation to survival via induction of survival pathways since no TRAIL-induced regulations are needed and suggest that short-lived anti-apoptotic protein Mcl1 exhibit large and rare fluctuations. More generally, our results highlight the importance of accounting for stochastic protein turnover to quantitatively understand signal transduction over extended durations, and imply that fluctuations of short-lived proteins deserve particular attention.

  16. Pegylated liposomal doxorubicin: appraisal of its current role in the management of epithelial ovarian cancer

    Directory of Open Access Journals (Sweden)

    Markman M

    2011-06-01

    Full Text Available Maurie MarkmanCancer Treatment Centers of America, Eastern Regional Medical Center, Philadelphia, PA, USAAbstract: Pegylated liposomal doxorubicin (PLD has become a major component in the routine management of epithelial ovarian cancer. The drug is frequently employed as a single agent in the platinum-resistant setting, and recently reported data reveal the superiority of the combination of PLD plus carboplatin, compared with the platinum drug plus paclitaxel, in delaying the time to disease progression in women with recurrent (potentially platinum-sensitive disease. Current research efforts involving PLD in ovarian cancer are focusing on adding novel targeted drugs to this cytotoxic agent. The utility of such approaches in the platinum-resistant population, compared with the sequential administration of single agents active in this setting, remains to be determined.Keywords: PLD, carboplatin, paclitaxel, platinum-sensitive, platinum-resistant

  17. Cardioprotective effect of cannabidiol in rats exposed to doxorubicin toxicity.

    Science.gov (United States)

    Fouad, Amr A; Albuali, Waleed H; Al-Mulhim, Abdulruhman S; Jresat, Iyad

    2013-09-01

    The potential protective effect of cannabidiol, the major non-psychotropic Cannabis constituent, was investigated against doxorubicin cardiotoxicity in rats. Cardiotoxicity was induced by six equal doses of doxorubicin (2.5mgkg(-1) i.p., each) given at 48h intervals over two weeks to achieve a total dose of 15mgkg(-1). Cannabidiol treatment (5mgkg(-1)/day, i.p.) was started on the same day of doxorubicin administration and continued for four weeks. Cannabidiol significantly reduced the elevations of serum creatine kinase-MB and troponin T, and cardiac malondialdehyde, tumor necrosis factor-α, nitric oxide and calcium ion levels, and attenuated the decreases in cardiac reduced glutathione, selenium and zinc ions. Histopathological examination showed that cannabidiol ameliorated doxorubicin-induced cardiac injury. Immunohistochemical analysis revealed that cannabidiol significantly reduced the expression of inducible nitric oxide synthase, nuclear factor-κB, Fas ligand and caspase-3, and increased the expression of survivin in cardiac tissue of doxorubicin-treated rats. These results indicate that cannabidiol represents a potential protective agent against doxorubicin cardiac injury. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Pegylated liposomal doxorubicin/carboplatin combination in ovarian cancer, progressing on single-agent pegylated liposomal doxorubicin

    OpenAIRE

    Grenader, Tal; Rosengarten, Ora; Isacson, Rut; Plotkin, Yevgeni; Gabizon, Alberto

    2012-01-01

    AIM: To assess the efficacy and safety of the combination of pegylated liposomal doxorubicin (PLD) and carboplatin in patients with recurrent epithelial ovarian carcinoma (ROC), following disease progression on single agent PLD.

  19. Down-regulated βIII-tubulin Expression Can Reverse Paclitaxel Resistance in A549/Taxol Cells Lines

    Directory of Open Access Journals (Sweden)

    Yinling ZHUO

    2014-08-01

    Full Text Available Background and objective Chemotherapy drug resistance is the primary causes of death in patients with pulmonary carcinoma which make tumor recurrence or metastasis. β-tubulin is the main cell targets of anti-microtubule drug. Increased expression of βIII-tubulin has been implicated in non-small cell lung cancer (NSCLC cell lines. To explore the relationship among the expression level of βIII-tubulin and the sensitivity of A549/Taxolcell lines to Taxol and cell cycles and cell apoptosis by RNA interference-mediated inhibition of βIII-tubulin in A549/Taxol cells. Methods Three pairs of siRNA targetd βIII-tubulin were designed and prepared, which were transfected into A549/Taxol cells using LipofectamineTM 2000. We detected the expression of βIII-tubulin mRNA using Real-time fluorescence qRT-PCR. Tedhen we selected the most efficient siRNA by the expression of βIII-tubulin mRNA in transfected group. βIII-tubulin protein level were mesured by Western blot. The taxol sensitivity in transfected group were evaluated by MTT assay. And the cell apoptosis and cell cycles were determined by flow cytometry. Results βIII-tubulin mRNA levels in A549/Taxol cells were significantly decreased in transfected grop by Real-time qRT-PCR than control groups. And βIII-tubulin siRNA-1 sequence showed the highest transfection efficiency, which was (87.73±4.87% (P<0.01; Western blot results showed that the expressional level of BIII tublin protein was significantly down-reulated in the transfectant cells than thant in the control cells. By MTT assay, we showed that the inhibition ratio of Taxol to A549/Taxol cells transfeced was higher than that of control group (51.77±4.60% (P<0.01. The early apoptosis rate of A549/Taxol cells in transfected group were significantly higher than that of control group (P<0.01; G2-M content in taxol group obviously increased than untreated samples by the cell cycle (P<0.05. Conclusion βIII-tubulin down-regulated significantly

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

    Directory of Open Access Journals (Sweden)

    Yu-Li Lo

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

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

    Science.gov (United States)

    2004-06-01

    176. within the range of 90-110% for QCs at low, [12] S. Lock , H. Witschi, F.S. Skelton, G. Hanasono, G.L. Plaa, Exp. Mol. Pathol. 21 (1974) 237...addition, the polarized localization of MRP1 in the basolateral membrane of the choroid plexus epithelium (203) suggests that it may significantly...feces (12.4%) ". Lock et al. performed disposition studies with dually labeled 1-NITC (a4C-isothiocyanate and 4-3H-naphthyl) with a ratio of 3 1H/ 1 4C

  2. Near-infrared triggered co-delivery of doxorubicin and quercetin by using gold nanocages with tetradecanol to maximize anti-tumor effects on MCF-7/ADR cells.

    Science.gov (United States)

    Zhang, Zhipeng; Xu, Shaohui; Wang, Yun; Yu, Yanna; Li, Fangzhou; Zhu, Hao; Shen, Yuanyuan; Huang, Shengtang; Guo, Shengrong

    2018-01-01

    Previously, combination chemotherapy of doxorubicin (DOX) and quercetin (QUR) was developed to improve antitumor effects and reverse multidrug resistance and several biocompatible nanocarriers, such as liposomes and micelles, were validated for their targeted delivery. In this study, we report a near-infrared (NIR)-responsive drug delivery system based on DOX and QUR co-loaded gold nanocages (AuNCs) with biotin modification. The system was simply fabricated by filling the hollow interiors of AuNCs with tetradecanol (TD), a phase-change material with a melting point of 39°C, to control the drug release. The main cause of multidrug resistance (MDR) of DOX is the overexpression of P-glycoprotein (P-gp), which can be inhibited by QUR. Thus the combination chemotherapy of DOX and QUR may provide a promising strategy for MDR. The in vitro cytotoxicity of DOX and QUR at several fixed mass ratios was carried out and showed that the combination index (CI) was the smallest at the ratio of 1:0.2, indicating that the best synergistic effect was achieved. The resultant nanocomplex (abbreviated as BPQD-AuNCs) exhibited fast release (80% released in 20min) and strong cytotoxicity against MCF-7/ADR cells (IC50, 1.5μg/mL) under NIR irradiation. Additionally, BPQD-AuNCs were found to generate a large amount of reactive oxygen species (ROS), to inhibit P-gp expression and ATP activity. Taken together, the results show that BPQD-AuNC is a prospective nano-delivery system for overcoming multidrug-resistant cancer. Copyright © 2017. Published by Elsevier Inc.

  3. Pegylated liposomal doxorubicin for relapsed epithelial ovarian cancer.

    Science.gov (United States)

    Lawrie, Theresa A; Bryant, Andrew; Cameron, Alison; Gray, Emma; Morrison, Jo

    2013-07-09

    Ovarian cancer is the eighth most common cancer in women and it is usually diagnosed at an advanced stage. The majority of ovarian tumours are epithelial in origin. Women with relapsed epithelial ovarian cancer (EOC) often have a reduced performance status with a limited life expectancy, therefore maintaining quality of life with effective symptom control is the main purpose of treatment. Drug treatment of relapsed disease is directed by the platinum-free interval: relapsed platinum-sensitive disease is usually re-treated with platinum-based therapy and platinum-resistant disease challenged with non-platinum drugs. However, the side-effects of chemotherapy agents may be severe and optimal treatment regimens are unclear. Pegylated liposomal doxorubicin (PLD), which contains a cytotoxic drug called doxorubicin hydrochloride is one of several treatment modalities that may be considered for single-agent treatment of relapsed EOC, or used in combination with other drugs. To assess the efficacy and safety of PLD in women with relapsed epithelial ovarian cancer (EOC). We searched the Cochrane Gynaecological Cancer Group (CGCG) trials register, CENTRAL, MEDLINE and EMBASE from 1990 to February 2013. We also searched online registers of clinical trials, abstracts of scientific meetings and reference lists of included studies. Randomised controlled trials (RCTs) that evaluated PLD in women diagnosed with relapsed epithelial ovarian cancer. Two review authors independently abstracted data to a pre-designed data collection form and assessed the risk of bias according to the Cochrane Handbook for Systematic Reviews of Interventions guidelines. Where possible, we pooled collected data in meta-analyses using RevMan 5.2 software. We included 14 RCTs that evaluated PLD alone or in combination with other drugs. Four RCTs contributed no data to the meta-analyses. Two studies compared PLD plus carboplatin (carbo) to paclitaxel (PAC)/carbo in women with platinum-sensitive relapsed EOC

  4. Severe Obesity and Insulin Resistance due to Deletion of the Maternal Gsα Allele Is Reversed by Paternal Deletion of the Gsα Imprint Control Region

    Science.gov (United States)

    Xie, Tao; Chen, Min; Gavrilova, Oksana; Lai, Edwin W.; Liu, Jie; Weinstein, Lee S.

    2008-01-01

    The G protein α-subunit Gsα mediates receptor-stimulated cAMP production and is imprinted with reduced expression from the paternal allele in specific tissues. Disruption of the Gsα maternal (but not paternal) allele leads to severe obesity, hypertriglyceridemia, and insulin resistance in mice and obesity in patients with Albright hereditary osteodystrophy. Paternal deletion of a Gsα imprint control region (1A) leads to loss of tissue-specific Gsα imprinting. To determine whether the metabolic abnormalities resulting from disruption of the Gsα maternal allele could be reversed by loss of paternal Gsα imprinting, females with a heterozygous Gsα exon 1 deletion were mated to males with heterozygous deletion of the imprint control region (1A) to generate mice with maternal Gsα deletion (E1m−), paternal 1A deletion (1Ap−), double mutants (E1m−:1Ap−), and wild type. E1m− mice developed obesity, glucose intolerance, insulin resistance, and hypertriglyceridemia, which were all normalized by the paternal 1A deletion in E1m−:1Ap− mice. Obesity in E1m− was associated with reduced energy expenditure and sympathetic nerve activity, and these were also normalized in E1m−:1Ap− mice. 1Ap− mice had reduced body weight associated with proportional decreases in fat and lean mass as well as increased activity levels. The metabolic phenotype resulting from maternal Gsα deletion is rescued by a genetic lesion that leads to loss of tissue-specific Gsα imprinting, consistent with this phenotype being a direct consequence of Gsα imprinting in one or more specific tissues. PMID:18202131

  5. A comparison of the effect of doxorubicin and phenol on the skeletal muscle. May doxorubicin be a new alternative treatment agent for spasticity?

    Science.gov (United States)

    Cullu, Emre; Ozkan, Ilhan; Culhaci, Nil; Alparslan, Bulent

    2005-03-01

    Since spasticity is still an unsolved problem for orthopaedic surgeons, different chemical agents are tried before surgery. Phenol is a chemical agent which has been used for spasticity treatment for a long time. Doxorubicin is an antitumoral agent that has recently been used for chemomyectomy. The intramuscular effects of phenol and two different dose of doxorubicin were compared in that experimental study. In the first group 0.5 mg/0.5 cm3 doxorubicin, in the second group 1 mg/0.5 doxorubicin and in the third group 5% aqueous solution of fenol/0.5 injection were applied into left quadriceps muscle of rats. Degeneration areas were wider in the high dose doxorubicin group (29.9%; 8.5-61), in comparison with the low dose doxorubicin group (6.4%; 3.1-12) and phenol group (4%; 0-14) after 6 weeks. Differences in degeneration area among three groups were statistically significant (P<0.001). The difference was significant between the high dose doxorubicin group and the phenol group (P=0.001) and also between the high dose doxorubicin group and the low dose doxorubicin group (P<0.001). The results of this study suggested that doxorubicin could provide an alternative treatment modality for neuromuscular disease causing spasticity and it has a dose-dependent effect. Further studies are needed for long-term comparison and clinical use of doxorubicin for spasticity treatment.

  6. Losartan improves the distribution and efficacy of doxorubicin in CT26 tumor.

    Science.gov (United States)

    Xiao, L; Hu, S Q; Wang, L Y; Liu, J X; Li, X Y

    2015-10-01

    The effectiveness of chemotherapeutic agents is impaired by limited delivery of chemotherapeutic agents to the tumor cells. Improving drug penetration in tumor tissues is very important. We tested whether losartan, a selective antagonist against type 1 angiotensin II receptors (AT1R) with noted antifibrotic activity, can enhance the penetration and efficacy of doxorubicin. BALB/C mice, which implanted with CT26 tumor cells, were divided into four groups: control, doxorubicin alone, losartan alone and doxorubicin + losartan combination groups. At day 0, the losartan alone and doxorubicin + losartan combination groups received losartan; and at day 8, the doxorubicin alone and doxorubicin + losartan combination groups received doxorubicin i.v. Tumor growth and intratumoral distribution of doxorubicin were evaluated. The mechanism underlying the enhanced anti-tumor effect of the combination of doxorubicin and losartan was investigated by immunohistochemical analysis. Treatment with losartan alone did not suppress tumor growth; In contrast, treatment with doxorubicin alone decreased tumor growth; losartan and doxorubicin were administered in combination, had a synergistic effect that the tumor growth was much more inhibited. The decreased proliferation as indicated by down-regulation of Ki67, and increased apoptosis as indicated by TUNEL and caspase-3 staining. The expression of tumor suppressor gene P53 increased in doxorubicin + losartan combination groups. Losartan can increase the therapeutic effectiveness of doxorubicin, yielding more great antitumor benefit. This study provided a rationale for initiating clinical trials using losartan in combination with chemotherapeutic agents to increase their therapeutic effectiveness.

  7. PEG-PE/clay composite carriers for doxorubicin: Effect of composite structure on release, cell interaction and cytotoxicity.

    Science.gov (United States)

    Kohay, Hagay; Sarisozen, Can; Sawant, Rupa; Jhaveri, Aditi; Torchilin, Vladimir P; Mishael, Yael G

    2017-06-01

    A novel drug delivery system for doxorubicin (DOX), based on organic-inorganic composites was developed. DOX was incorporated in micelles (M-DOX) of polyethylene glycol-phosphatidylethanolamine (PEG-PE) which in turn were adsorbed by the clay, montmorillonite (MMT). The nano-structures of the PEG-PE/MMT composites of LOW and HIGH polymer loadings were characterized by XRD, TGA, FTIR, size (DLS) and zeta measurements. These measurements suggest that for the LOW composite a single layer of polymer intercalates in the clay platelets and the polymer only partially covers the external surface, while for the HIGH composite two layers of polymer intercalate and a bilayer may form on the external surface. These nanostructures have a direct effect on formulation stability and on the rate of DOX release. The release rate was reversely correlated with the degree of DOX interaction with the clay and followed the sequence: M-DOX>HIGH formulation>LOW formulation>DOX/MMT. Despite the slower release from the HIGH formulation, its cytotoxicity effect on sensitive cells was as high as the "free" DOX. Surprisingly, the LOW formulation, with the slowest release, demonstrated the highest cytotoxicity in the case of Adriamycin (ADR) resistant cells. Confocal microscopy images and association tests provided an insight into the contribution of formulation-cell interactions vs. the contribution of DOX release rate. Internalization of the formulations was suggested as a mechanism that increases DOX efficiency, particularly in the ADR resistant cell line. The employment of organic-inorganic hybrid materials as drug delivery systems, has not reached its full potential, however, its functionality as an efficient tunable release system was demonstrated. DOX PEG-PE/clay formulations were design as an efficient drug delivery system. The main aim was to develop PEG-PE/clay formulations of different structures based on various PEG-PE/clay ratios in order to achieve tunable release rates, to control

  8. Testosterone Antagonizes Doxorubicin-Induced Senescence of Cardiomyocytes.

    Science.gov (United States)

    Altieri, Paola; Barisione, Chiara; Lazzarini, Edoardo; Garuti, Anna; Bezante, Gian Paolo; Canepa, Marco; Spallarossa, Paolo; Tocchetti, Carlo Gabriele; Bollini, Sveva; Brunelli, Claudio; Ameri, Pietro

    2016-01-08

    Chronic cardiotoxicity is less common in male than in female patients receiving doxorubicin and other anthracyclines at puberty and adolescence. We hypothesized that this sex difference might be secondary to distinct activities of sex hormones on cardiomyocyte senescence, which is thought to be central to the development of long-term anthracycline cardiomyopathy. H9c2 cells and neonatal mouse cardiomyocytes were exposed to doxorubicin with or without prior incubation with testosterone or 17β-estradiol, the main androgen and estrogen, respectively. Testosterone, but not 17β-estradiol, counteracted doxorubicin-elicited senescence. Downregulation of telomere binding factor 2, which has been pinpointed previously as being pivotal to doxorubicin-induced senescence, was also prevented by testosterone, as were p53 phosphorylation and accumulation. Pretreatment with the androgen receptor antagonist flutamide, the phosphatidylinositol 3 kinase inhibitor LY294002, and the nitric oxide synthase inhibitor L-NG-nitroarginine methyl ester abrogated the reduction in senescence and the normalization of telomere binding factor 2 levels attained by testosterone. Consistently, testosterone enhanced the phosphorylation of AKT and nitric oxide synthase 3. In H9c2 cells, doxorubicin-stimulated senescence was still observed up to 21 days after treatment and increased further when cells were rechallenged with doxorubicin 14 days after the first exposure to mimic the schedule of anthracycline-containing chemotherapy. Remarkably, these effects were also inhibited by testosterone. Testosterone protects cardiomyocytes against senescence caused by doxorubicin at least in part by modulating telomere binding factor 2 via a pathway involving the androgen receptor, phosphatidylinositol 3 kinase, AKT, and nitric oxide synthase 3. This is a potential mechanism by which pubescent and adolescent boys are less prone to chronic anthracycline cardiotoxicity than girls. © 2016 The Authors. Published on

  9. Interference with endogenous EZH2 reverses the chemotherapy drug resistance in cervical cancer cells partly by up-regulating Dicer expression.

    Science.gov (United States)

    Cai, Liqiong; Wang, Zehua; Liu, Denghua

    2016-05-01

    lower level of Dicer in HeLa/DDP cells. Finally, in vivo tumorigenicity experiments results demonstrated that interference with endogenous EZH2 by shRNA specific to EZH2 or inhibition EZH2 by DZNep could significantly increase antitumor effects in nude mice. Thus, inhibiting the levels of endogenous EZH2 effectively reversed the cisplatin resistance and increased the cisplatin sensitivity in cisplatin-resistant HeLa/DDP cells. EZH2 might be a potential target for treating chemotherapeutic drug-resistant cervical cancers.

  10. Influence of nicotine on doxorubicin and cyclophosphamide combination treatment-induced spatial cognitive impairment and anxiety-like behavior in rats.

    Science.gov (United States)

    Kitamura, Yoshihisa; Kanemoto, Erika; Sugimoto, Misaki; Machida, Ayumi; Nakamura, Yuka; Naito, Nanami; Kanzaki, Hirotaka; Miyazaki, Ikuko; Asanuma, Masato; Sendo, Toshiaki

    2017-04-01

    In the present study, we examined the effects of nicotine on cognitive impairment, anxiety-like behavior, and hippocampal cell proliferation in rats treated with a combination of doxorubicin and cyclophosphamide. Combined treatment with doxorubicin and cyclophosphamide produced cognitive impairment and anxiety-like behavior in rats. Nicotine treatment reversed the inhibition of novel location recognition induced by the combination treatment. This effect of nicotine was blocked by methyllycaconitine, a selective α7 nicotinic acetylcholine receptor (nAChR) antagonist, and dihydro-β-erythroidine, a selective α4β2 nAChR antagonist. In addition, nicotine normalized the amount of spontaneous alternation seen during the Y-maze task, which had been reduced by the combination treatment. This effect of nicotine was inhibited by dihydro-β-erythroidine. In comparison, nicotine did not affect the anxiety-like behavior induced by the combination treatment. Furthermore, the combination treatment reduced the number of proliferating cells in the subgranular zone of the hippocampal dentate gyrus, and this was also prevented by nicotine. Finally, the combination of doxorubicin and cyclophosphamide significantly reduced hippocampal α7 nAChR mRNA expression. These results suggest that nicotine inhibits doxorubicin and cyclophosphamide-induced cognitive impairment via α7 nAChR and α4β2 nAChR, and also enhances hippocampal neurogenesis.

  11. MUC1* is a determinant of trastuzumab (Herceptin) resistance in breast cancer cells.

    Science.gov (United States)

    Fessler, Shawn P; Wotkowicz, Mark T; Mahanta, Sanjeev K; Bamdad, Cynthia

    2009-11-01

    In the United States, 211,000 women are diagnosed each year with breast cancer. Of the 42,000 breast cancer patients who overexpress the HER2 growth factor receptor, Herceptin). Despite those statistics, women diagnosed with breast cancer are now tested to determine how much of this important growth factor receptor is present in their tumor because patients whose treatment includes trastuzumab are three-times more likely to survive for at least 5 years and are two-times more likely to survive without a cancer recurrence. Unfortunately, even among the group whose cancers originally respond to trastuzumab, 25% of the metastatic breast cancer patients acquire resistance to trastuzumab within the first year of treatment. Follow-on "salvage" therapies have prolonged life for this group but have not been curative. Thus, it is critically important to understand the mechanisms of trastuzumab resistance and develop therapies that reverse or prevent it. Here, we report that molecular analysis of a cancer cell line that was induced to acquire trastuzumab resistance showed a dramatic increase in the amount of the cleaved form of the MUC1 protein, called MUC1*. We recently reported that MUC1* functions as a growth factor receptor on cancer cells and on embryonic stem cells. Here, we show that treating trastuzumab-resistant cancer cells with a combination of MUC1* antagonists and trastuzumab, reverses the drug resistance. Further, HER2-positive cancer cells that are intrinsically resistant to trastuzumab became trastuzumab-sensitive when treated with MUC1* antagonists and trastuzumab. Additionally, we found that tumor cells that had acquired Herceptin resistance had also acquired resistance to standard chemotherapy agents like Taxol, Doxorubicin, and Cyclophosphamide. Acquired resistance to these standard chemotherapy drugs was also reversed by combined treatment with the original drug plus a MUC1* inhibitor.

  12. Improved Efficacy of Liposomal Doxorubicin Treatment of Superficial Tumors by Thermotherapy.

    Science.gov (United States)

    Ping, Xiong; Angang, Ding; Xia, Gong; Yinzhu, Zhao; Jia, Li; Guofeng, Shen; Yazhu, Chen

    2016-04-01

    Our study aimed to investigate the effect of ultrasonic thermotherapy on the targeted delivery of liposomal doxorubicin to superficial tumors, local drug concentrations in tumor tissue, and the curative effect of chemotherapy. Twenty rabbits with VX2 tumors transplanted into the superficial muscle of the hind limb were randomly assigned to the following 4 treatment groups: (1) free doxorubicin, (2) liposomal doxorubicin hydrochloride, (3) liposomal doxorubicin hydrochloride plus 41 °C thermotherapy, and (4) liposomal doxorubicin hydrochloride plus 43 °C thermotherapy. Ultrasonic thermotherapy was delivered at 41 °C to 43 °C. Plasma, tumor, and organ/tissue homogenates were analyzed by high-pressure liquid chromatography to determine doxorubicin concentrations. The drug concentration in plasma and tumor tissue was significantly higher in the liposomal doxorubicin hydrochloride plus thermotherapy group than in the liposomal doxorubicin hydrochloride and free doxorubicin groups, but there were no significant differences among the 4 groups in the concentration in heart or kidney tissue. Combining thermotherapy with liposomal doxorubicin hydrochloride chemotherapy significantly increased the concentration of the drug in tumor tissue. The doxorubicin concentration was significantly higher in the liposomal doxorubicin hydrochloride plus 41 °C thermotherapy group. © The Author(s) 2015.

  13. Experimental and theoretical studies of active control of resistive wall mode growth in the EXTRAP T2R reversed-field pinch

    Science.gov (United States)

    Drake, J. R.; Brunsell, P. R.; Yadikin, D.; Cecconello, M.; Malmberg, J. A.; Gregoratto, D.; Paccagnella, R.; Bolzonella, T.; Manduchi, G.; Marrelli, L.; Ortolani, S.; Spizzo, G.; Zanca, P.; Bondeson, A.; Liu, Y. Q.

    2005-07-01

    Active feedback control of resistive wall modes (RWMs) has been demonstrated in the EXTRAP T2R reversed-field pinch experiment. The control system includes a sensor consisting of an array of magnetic coils (measuring mode harmonics) and an actuator consisting of a saddle coil array (producing control harmonics). Closed-loop (feedback) experiments using a digital controller based on a real time Fourier transform of sensor data have been studied for cases where the feedback gain was constant and real for all harmonics (corresponding to an intelligent-shell) and cases where the feedback gain could be set for selected harmonics, with both real and complex values (targeted harmonics). The growth of the dominant RWMs can be reduced by feedback for both the intelligent-shell and targeted-harmonic control systems. Because the number of toroidal positions of the saddle coils in the array is half the number of the sensors, it is predicted and observed experimentally that the control harmonic spectrum has sidebands. Individual unstable harmonics can be controlled with real gains. However if there are two unstable mode harmonics coupled by the sideband effect, control is much less effective with real gains. According to the theory, complex gains give better results for (slowly) rotating RWMs, and experiments support this prediction. In addition, open loop experiments have been used to observe the effects of resonant field errors applied to unstable, marginally stable and robustly stable modes. The observed effects of field errors are consistent with the thin-wall model, where mode growth is proportional to the resonant field error amplitude and the wall penetration time for that mode harmonic.

  14. Reverse logistics

    NARCIS (Netherlands)

    M.P. de Brito (Marisa); S.D.P. Flapper; R. Dekker (Rommert)

    2002-01-01

    textabstractThis paper gives an overview of scientific literature that describes and discusses cases of reverse logistics activities in practice. Over sixty case studies are considered. Based on these studies we are able to indicate critical factors for the practice of reverse logistics. In

  15. Gemcitabine, Navelbine, and Doxorubicin as Treatment for Patients with Refractory or Relapsed T-Cell Lymphoma

    Directory of Open Access Journals (Sweden)

    Zhengzi Qian

    2015-01-01

    Full Text Available T-cell lymphoma (TCL is resistant to conventional chemotherapy. We retrospectively evaluated the therapeutic efficiency and toxicity of gemcitabine, navelbine, and doxorubicin (GND in patients with refractory or relapsed TCL. From 2002 to 2012, 69 patients with refractory or relapsed TCL received GND treatment in our hospital. The treatment protocol comprised gemcitabine (800 mg/m2, group 1; 1000 mg/m2, group 2 on days 1 and 8, navelbine (25 mg/m2 on day 1, and doxorubicin (20 mg/m2 on day 1, repeated every 3 weeks. The overall response rate (ORR was 65.2%. The median overall survival (OS was 36 months. The 5-year estimated OS rate was 32.4%. The GND regimen was well tolerated. Subgroup analysis demonstrated that the ORR and CR for group 1 were similar. A longer median OS was observed for group 1. Significant difference in grades 3-4 toxicities was observed between groups 1 and 2 (P=0.035. Our study indicated that gemcitabine (800 mg/m2 on days 1 and 8 every 21 days was favorable for pretreated TCL patients.

  16. [Which patients with ovarian cancer shows the combination of trabectedin with pegylated liposomal doxorubicin].

    Science.gov (United States)

    Khokhlova, S V; Cherkasova, M V; Orel, N F; Limareva, S V; Bazaeva, I Ia; Gorbunova, V A

    2013-01-01

    Given the high rate of recurrence of ovarian cancer, the search for new therapeutic strategies are topical issue. According to various studies the effectiveness of drug treatment relapse depends on the platinum-free interval, increasing in proportion to its duration. If therapy is platinum-resistant recurrent ovarian cancer is a standard approach, the treatment of platinum-sensitive recurrent algorithm is not fully defined. Comparison of platinum and non-platinum combinations revealed the advantage of combined platinum- treatment for patients with platinum-free interval of more than 6 months without an increase in life expectancy. Non-platinum combination of trabected in with pegylated liposomal doxorubicin has shown comparable efficacy with an advantage in overall survival in patients with platinum-free interval of 6-12 months. A platinum-free interval prolongation by the use of non-platinum mode increases the efficiency of subsequent platinum-based therapy, increasing the life expectancy of patients. Currently under study molecular markers and prognostic factors allowing to define a group of patients who have the greatest benefit from the use trabectedin with pegylated liposomal doxorubicin as second-line chemotherapy.

  17. Folic acid conjugated magnetic drug delivery system for controlled release of doxorubicin

    Energy Technology Data Exchange (ETDEWEB)

    Andhariya, Nidhi, E-mail: nidhiandhariya@gmail.com [Thapar University, School of Physics and Materials Science (India); Upadhyay, Ramesh [Charotar University of Science and Technology, P.D. Patel Institute of Applied Sciences (India); Mehta, Rasbindu [Maharaja Krishnakumarsinhji Bhavnagar University, Department of Physics (India); Chudasama, Bhupendra, E-mail: bnchudasama@gmail.com [Thapar University, School of Physics and Materials Science (India)

    2013-01-15

    Targeting tumors by means of their vascular endothelium is a promising strategy, which utilizes targets that are easily accessible, stable, and do not develop resistance against therapeutic agents. Folate receptor is a highly specific tumor marker, frequently over expressed in cancer tumors. In the present study, an active drug delivery system, which can effectively target cancer cells by means of folate receptor-mediated endocytosis, have ability to escape from opsonization and capability of magnetic targeting to withstand the drag force of the body fluid have been designed and synthesized. The core of the drug delivery system is of mono-domain magnetic particles of magnetite. Magnetite nanoparticles are shielded with PEG, which prevents their phagocytosis by reticuloendothelial system. These PEG shielded magnetite nanoparticles are further decorated with an antitumor receptor-folic acid and loaded with an antineoplastic agent doxorubicin. An in vitro drug loading and release kinetics study reveals that the drug delivery system can take 52 % of drug load and can release doxorubicin over a sustained period of 7 days. The control and sustained release over a period of several days may find its practical utilities in chemotherapy where frequent dosing is not possible.

  18. Cyclophosphamide and Doxorubicin Induced Melanonychia: A Case Report.

    Science.gov (United States)

    Prajapati, Vivek Bhanubhai; Madhyastha, Sharath; Acharya, Raviraj; Gopalaswamy, Vinaya; Doddamani, Akhila

    2017-01-01

    Chemotherapeutic agents may rarely cause discoloration and hyperpigmentation of the nails. We present a patient who developed blackish discoloration of nails also referred as melanonychia during six cycles of R-CHOP chemotherapy regimen (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone) for the treatment of Non Hodgkin Lymphoma (NHL) follicular type. The patient developed blackish brown discoloration in all the nails. As suggested by previous literature evidence the melanonychia could be associated with cyclophosphamide and doxorubicin. According to the Naranjo causality assessment scale, we established that there was a 'probable' association of nail discoloration with the drug.

  19. A Rare Class of New Dimeric Naphtoquiones from Diospyros lotus have Multidrug Reversal and Antiproliferative Effects

    Directory of Open Access Journals (Sweden)

    Dr. Abdur eRauf

    2015-12-01

    Full Text Available Three new dimeric naphthoquinones, 5,4′-dihydroxy-1′-methoxy-6,6′-dimethyl-7,3′-binaphthyl-1,4,5′,8′-tetraone (1, 5′,8′-dihydroxy-5-methoxy-6,6′-dimethyl-7,3′-binaphthyl-1,4,1′,4′-tetraone (2 and 8,5′,8′-trihydroxy-6,6′-dimethyl-7,3′-binaphthyl-1,4,1′,4′-tetraone (3, were isolated from the roots of Diospyros lotus. Their structures were elucidated by spectroscopic techniques, including 1D and 2D NMR, such as HSQC, HMBS, NOESY and J resolved. Compounds 1-3 were evaluated for their effects on the reversion of multidrug resistance (MDR mediated by P-glycoprotein through use of the rhodamine-123 exclusion screening test on human ABCB1 gene transfected L5178Y mouse T-cell lymphoma. Compounds 1-3 were also assessed for their antiproliferative and cytotoxic effects on L5178 and L5178Y mouse T-cell lymphoma lines. Both 1 and 2 exhibited promising antiproliferative and MDR-reversing effects in a dose dependent manner. The effects of the tested compounds on the activity of doxorubicin were observed to vary from slight antagonism to antagonism.

  20. EGCG/gelatin-doxorubicin gold nanoparticles enhance therapeutic efficacy of doxorubicin for prostate cancer treatment.

    Science.gov (United States)

    Tsai, Li-Chu; Hsieh, Hao-Ying; Lu, Kun-Ying; Wang, Sin-Yu; Mi, Fwu-Long

    2016-01-01

    Development of epigallocatechin gallate (EGCG) and gelatin-doxorubicin conjugate (GLT-DOX)-coated gold nanoparticles (DOX-GLT/EGCG AuNPs) for fluorescence imaging and inhibition of prostate cancer cell growth. AuNPs alternatively coated with EGCG and DOX-GLT conjugates were prepared by a layer-by-layer assembly method. The physicochemical properties of the AuNPs and the effect of Laminin 67R receptor-mediated endocytosis on the anticancer efficacy of the AuNPs were examined. The AuNPs significantly inhibit the proliferation of PC-3 cancer cell and the enzyme-responsive intracellular release of DOX could be tracked by monitoring the recovery of the fluorescence signal of DOX. Laminin 67R receptor-mediated delivery of DOX using the AuNPs enhanced cellular uptake of DOX and improved apoptosis of PC-3 cells.

  1. Reverse Osmosis

    Indian Academy of Sciences (India)

    ment of Civil Engineering and is presently the. Chairman of Center for. Sustainable Technologies,. Indian Institute of Science,. Bangalore. His research areas include, unsaturated soil behaviour, hazardous waste management, water quality and remediation of contaminated water. Keywords. Osmosis, reverse osmosis,.

  2. Reverse Osmosis

    Indian Academy of Sciences (India)

    and is an Associate Faculty at Center for Sustainable. Technologies, Indian. Institute of Science,. Bangalore. His research areas include, unsaturated soil behaviour, hazardous waste management, water quality and remediation of contaminated water. Keywords. Osmosis, reverse osmosis, desalinatiion, seawater, water.

  3. Reverse Osmosis

    Indian Academy of Sciences (India)

    /fulltext/reso/012/05/0037-0040. Keywords. Osmosis; reverse osmosis; desalinatiion; seawater; water purification. Author Affiliations. Sudhakar M Rao1. Department of Civil Engineering, Indian Institute of Science, Bangalore 560012, India.

  4. Reversible Sterilization

    Science.gov (United States)

    Largey, Gale

    1977-01-01

    Notes that difficult questions arise concerning the use of sterilization for alleged eugenic and euthenic purposes. Thus, how reversible sterilization will be used with relation to the poor, mentally ill, mentally retarded, criminals, and minors, is questioned. (Author/AM)

  5. An etoposide-resistant lung cancer subline overexpresses the multidrug resistance-associated protein.

    Science.gov (United States)

    Doyle, L. A.; Ross, D. D.; Ordonez, J. V.; Yang, W.; Gao, Y.; Tong, Y.; Belani, C. P.; Gutheil, J. C.

    1995-01-01

    We have characterised an etoposide-resistant subline of the small-cell lung cancer cell line, UMCC-1, derived at our centre. Subline UMCC-1/VP was developed by culturing the parent line in increasing concentrations of etoposide over 16 months. UMCC-1/VP is 20-fold resistant to etoposide by MTT assays, relative to the parent line, and is cross-resistant to doxorubicin, vincristine and actinomycin D, but not to taxol, cisplatin, melphalan, thiotepa or idarubicin. Topoisomerase II immunoblotting demonstrates a 50% reduction of the protein in the resistant subline. The UMCC-1/VP subline demonstrates a marked decrease in the accumulation of [3H]etoposide relative to the parent line, as well as a modest reduction in the accumulation of daunorubicin. Reverse transcription-polymerase chain reaction assays demonstrate no detectable mdr1 expression but marked expression of the multidrug resistance-associated protein (MRP) gene in the resistant subline. Northern blotting with an MRP cDNA probe confirms marked overexpression of the MRP gene only in the UMCC-1/VP subline. Western blotting with antisera against MRP peptide confirms a 195 kDa protein band in the UMCC-1/VP subline. Southern blotting experiments demonstrate a 10-fold amplification of the MRP gene in the resistant subline. Depletion of glutathione with buthionine sulphoximine sensitised UMCC-1/VP cells to daunorubicin and etoposide. Our studies indicate that MRP gene expression may be induced by etoposide and may lead to reduced accumulation of the drug. Images Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 PMID:7669558

  6. Antitumor activity of doxorubicine-loaded nanoemulsion against ...

    African Journals Online (AJOL)

    Purpose: To evaluate the antitumor activity of doxorubicine (DOX)-loaded nanoemulsion (NE) on. Ehrlich ascites ... However, its clinical application is limited by its harmful side effects, the most significant of which is its cardiotoxicity that can lead to cardiomyopathy and congestive ... (HCl) were purchased from Leo Chem., S.

  7. Synthesis and characterisation of doxorubicin-loaded functionalised ...

    African Journals Online (AJOL)

    Synthesis and characterisation of doxorubicin-loaded functionalised cobalt ferrite nanoparticles and their in vitro anti-tumour activity under an AC-magnetic field. ... Results: XG coating decreased the contact angle of the native CFNPs from 92° to 40°, which indicates that it modified the CFNP surface from hydrophobic to ...

  8. Cisplatin versus cisplatin plus doxorubicin for standard-risk hepatoblastoma

    NARCIS (Netherlands)

    Perilongo, G.; Maibach, R.; Shafford, E.; Brugieres, L.; Brock, P.; Morland, B.; de Camargo, B.; Zsiros, J.; Roebuck, D.; Zimmermann, A.; Aronson, D.; Childs, M.; Widing, E.; Laithier, V.; Plaschkes, J.; Pritchard, J.; Scopinaro, M.; Czauderna, P.

    2009-01-01

    Background: Preoperative cisplatin alone may be as effective as cisplatin plus doxorubicin in standard-risk hepatoblastoma (a tumor involving three or fewer sectors of the liver that is associated with an alpha-fetoprotein level of >100 ng per milliliter). Methods: Children with standard-risk

  9. Cisplatin versus Cisplatin plus Doxorubicin for Standard-Risk Hepatoblastoma

    NARCIS (Netherlands)

    Perilongo, Giorgio; Maibach, Rudolf; Shafford, Elisabeth; Brugieres, Laurence; Brock, Penelope; Morland, Bruce; de Camargo, Beatriz; Zsiros, Jozsef; Roebuck, Derek; Zimmermann, Arthur; Aronson, Daniel; Childs, Margaret; Widing, Eva; Laithier, Veronique; Plaschkes, Jack; Pritchard, Jon; Scopinaro, Marcello; MacKinlay, Gordon; Czauderna, Piotr

    2009-01-01

    Background Preoperative cisplatin alone may be as effective as cisplatin plus doxorubicin in standard-risk hepatoblastoma (a tumor involving three or fewer sectors of the liver that is associated with an alpha-fetoprotein level of >100 ng per milliliter). Methods Children with standard-risk

  10. Kaposi's sarcoma: Good outcome with doxorubicin, bleomycin and ...

    African Journals Online (AJOL)

    We prospectively treated 12 patients with an institutional review board-approved protocol consisting of four monthly courses of doxorubicin (Adriamycin), bleomycin and vincristine sulphate (ABV), with highly active antiretroviral therapy (HAART) plus co-trimoxazole prophylaxis for those who were HIV-positive, with ...

  11. Constitutively activated ERK sensitizes cancer cells to doxorubicin ...

    Indian Academy of Sciences (India)

    2017-02-03

    Feb 3, 2017 ... Constitutively activated ERK sensitizes cancer cells to doxorubicin: Involvement of p53-EGFR-ERK pathway. RATNA KUMARI. 1,†. , SURBHI CHOUHAN. 1,†. , SNAHLATA SINGH. 1,†. , RISHI RAJ CHHIPA. 2. ,. AMRENDRA KUMAR AJAY. 3 and MANOJ KUMAR BHAT*. National Centre for Cell Science, ...

  12. Eleutheroside E inhibits doxorubicin-induced inflammation and ...

    African Journals Online (AJOL)

    Purpose: To identify the effects of eleutheroside E (EE) on apoptosis and inflammation induced by doxorubicin (DOX) in H9c2 cells and to investigate the underlying mechanisms. Methods: The effect of EE on H9c2 cell viability was determined using Cell Counting Kit-8 (CCK8). EE effect on DOX-induced apoptosis and ...

  13. INFLUENCE OF METRONIDAZOLE ON BIOLOGICAL ACTION OF DOXORUBICIN

    Directory of Open Access Journals (Sweden)

    S. A. Yagubov

    2017-01-01

    Full Text Available Purpose. Investigation of the effect of the Metronizatol on the biological effect of Doxirubicin.Materials and methods. The studies were performed in the CBA/Lac males and C57Bl/6 females mice grafted with melanoma B16 and mucinous ovarian cancer CaO‑1. Metronidazole and Doxorubicin were used in the work. The antitumor effect was assessed by tumor volume and inhibition of tumor growth.Results. The data obtained indicate that Metronidazole used in oncologic practice for the treatment and prevention of infectious complications, and as a radiosensitizer, can enhance the antitumor effect of Doxorubicin, but this effect is accompanied by a significant increase of the cytostatic toxicity. These effects are leveled by increasing the interval between injections of Metronidazole and Doxorubicin up to 4 hours.Conclusion. The enhancement of the antitumor activity of Doxorubicin under the influence of Metronidazole depends on the interval between the administration of these drugs. When Metronidazole is used in cancer patients, the possibility of enhancing the toxic effect of cytostatics should be considered when they are simultaneously exposed. Patients receiving chemotherapy should be administered antitumor drugs no earlier than 4 hours after exposure to Metronidazole. 

  14. Cisplatin versus cisplatin plus doxorubicin for standard-risk hepatoblastoma.

    NARCIS (Netherlands)

    Perilongo, G.; Maibach, R.; Shafford, E.; Brugieres, L.; Brock, P.; Morland, B.; Camargo, B. de; Zsiros, J.; Roebuck, D.; Zimmermann, A.; Aronson, D.C.; Childs, M.; Widing, E.; Laithier, V.; Plaschkes, J.; Pritchard, J.; Scopinaro, M.; MacKinlay, G.; Czauderna, P.

    2009-01-01

    BACKGROUND: Preoperative cisplatin alone may be as effective as cisplatin plus doxorubicin in standard-risk hepatoblastoma (a tumor involving three or fewer sectors of the liver that is associated with an alpha-fetoprotein level of >100 ng per milliliter). METHODS: Children with standard-risk

  15. Antitumor activity of doxorubicine-loaded nanoemulsion against ...

    African Journals Online (AJOL)

    Tropical Journal of Pharmaceutical Research ... Results: DOX/LNE group reduced levels of serum enzymes and lowered damage to heart tissues relative to DOX-Sol group. The MST of the DOX/LNE ... on the heart. Keywords: Doxorubicine, Anti-tumor activity, Mean survival time, Heart histology, Nanoemulsion, Lipid profile ...

  16. Enhancing anti-tumor efficacy of Doxorubicin by non-covalent conjugation to gold nanoparticles - in vitro studies on feline fibrosarcoma cell lines.

    Directory of Open Access Journals (Sweden)

    Michał Wójcik

    Full Text Available BACKGROUND: Feline injection-site sarcomas are malignant skin tumors of mesenchymal origin, the treatment of which is a challenge for veterinary practitioners. Methods of treatment include radical surgery, radiotherapy and chemotherapy. The most commonly used cytostatic drugs are cyclophosphamide, doxorubicin and vincristine. However, the use of cytostatics as adjunctive treatment is limited due to their adverse side-effects, low biodistribution after intravenous administration and multidrug resistance. Colloid gold nanoparticles are promising drug delivery systems to overcome multidrug resistance, which is a main cause of ineffective chemotherapy treatment. The use of colloid gold nanoparticles as building blocks for drug delivery systems is preferred due to ease of surface functionalization with various molecules, chemical stability and their low toxicity. METHODS: Stability and structure of the glutathione-stabilized gold nanoparticles non-covalently modified with doxorubicin (Au-GSH-Dox was confirmed using XPS, TEM, FT-IR, SAXRD and SAXS analyses. MTT assay, Annexin V and Propidium Iodide Apoptosis assay and Rhodamine 123 and Verapamil assay were performed on 4 feline fibrosarcoma cell lines (FFS1WAW, FFS1, FFS3, FFS5. Statistical analyses were performed using Graph Pad Prism 5.0 (USA. RESULTS: A novel approach, glutathione-stabilized gold nanoparticles (4.3 +/- 1.1 nm in diameter non-covalently modified with doxorubicin (Au-GSH-Dox was designed and synthesized. A higher cytotoxic effect (p<0.01 of Au-GSH-Dox than that of free doxorubicin has been observed in 3 (FFS1, FFS3, FFS1WAW out of 4 feline fibrosarcoma cell lines. The effect has been correlated to the activity of glycoprotein P (main efflux pump responsible for multidrug resistance. CONCLUSIONS: The results indicate that Au-GSH-Dox may be a potent new therapeutic agent to increase the efficacy of the drug by overcoming the resistance to doxorubicin in feline fibrosarcoma cell lines

  17. Reversible electrical resistance switching in GeSbTe thin films : An electrolytic approach without amorphous-crystalline phase-change

    NARCIS (Netherlands)

    Pandian, Ramanathaswamy; Kooi, Bart J.; Palasantzas, George; De Hosson, Jeff Th. M.; Wouters, DJ; Hong, S; Soss, S; Auciello, O

    2008-01-01

    Besides the well-known resistance switching originating from the amorphous-crystalline phase-change in GeSbTe thin films, we demonstrate another switching mechanism named 'polarity-dependent resistance (PDR) switching'. 'Me electrical resistance of the film switches between a low- and high-state

  18. β-elemene reverses the drug resistance of A549/DDP lung cancer cells by activating intracellular redox system, decreasing mitochondrial membrane potential and P-glycoprotein expression, and inducing apoptosis.

    Science.gov (United States)

    Yao, Chengcai; Jiang, Jie; Tu, Yuanrong; Ye, Shefang; Du, Haoxin; Zhang, Yi

    2014-07-01

    β-elemene (β-ELE) injection is a new anticancer drug extracted from Curcuma zedoaria Roscoe that has been widely used to treat malignant tumors. Recent studies show that β-ELE reverses the drug resistance of tumor cells. To explore the possible mechanisms of β-ELE, we investigated its effects on cisplatin (DDP)-resistant human lung adenocarcinoma A549/DDP cells. The effects of β-ELE on the growth of A549/DDP cells in vitro were determined by MTT assay. Apoptosis was assessed by fluorescence microscopy with Hoechst 33258 staining, flow cytometry with Annexin V-FITC/propium iodide double staining; mitochondrial membrane potential using JC-1 fluorescence probe and laser confocal scanning microscopy, and intracellular reactive oxygen species levels were measured by 2',7'-dichlorfluorescein-diacetate staining and flow cytometry; and contents of cytosolic glutathione were determined by glutathione assay kits. Intracellular Rhodamine-123 fluorescence intensity was detected by flow cytometry, and the expression of P-glycoprotein (P-gp) was detected by Western blotting. β-ELE inhibited the proliferation of A549/DDP cells in a time- and dose-dependent manner. Furthermore, β-ELE enhanced the sensitivity of A549/DDP cells to cisplatin and reversed the drug resistance of A549/DDP cells. Consistent with a role in activating apoptosis, β-ELE decreased mitochondrial membrane potential, increased intracellular reactive oxygen species concentration and intracellular accumulation of Rhodamine-123, decreased the cytoplasmic glutathione levels and the expression of P-gp in a time- and dose-dependent manner. These results define a pathway of β-ELE function that involves decreased mitochondrial membrane potential and P-gp expression activated intracellular redox system, and induced apoptosis leading to reverse drug resistance.

  19. Radiation effect studies on anticancer drugs, cyclophosphamide and doxorubicin for radiation sterilization

    Science.gov (United States)

    Varshney, L.; Dodke, P. B.

    2004-12-01

    Two anticancer drugs, cyclophosphamide (CPH) and doxorubicin hydrochloride (DOXO), in powder form were exposed to a range of doses of 60Co gamma and electron beam radiation to study the effects of ionizing radiation. Pharmacopoeia tests, discolouration, degradation products, effect of irradiation temperature and dose rate were investigated. CPH undergoes less than 2% degradation at 30 kGy. Chromatographic studies revealed formation of several trace level degradation products, discolouration and free radicals in the irradiated CPH. N, N-bis (2-chloroethyl) group in the molecule is particularly sensitive to radiation degradation. Irradiation to 5 kGy at low temperature (77 K) did not result in significant changes. DOXO was observed to be quite radiation resistant and did not undergo significant changes in its physico-chemical properties and degradation product profile. It can be radiation sterilized at normal sterilization dose of 25 kGy.

  20. VCPA, a novel synthetic derivative of α-tocopheryl succinate, sensitizes human gastric cancer to doxorubicin-induced apoptosis via ROS-dependent mitochondrial dysfunction.

    Science.gov (United States)

    Wu, Han; Liu, Shaoping; Gong, Jun; Liu, Jiuyang; Zhang, Qian; Leng, Xiaohua; Zhang, Nian; Li, Yan

    2017-05-01

    Gastric carcinoma is a common malignant disease worldwide and has a dismal prognosis. Doxorubicin (DOX), one of the most widely used chemotherapeutic agents, has limited use because of its side effects and the development of tumor-cell resistance. Combinations of doxorubicin and non-cross-resistant agents have been required for adjuvant chemotherapy of gastric cancer. Here, we report that VCPA, a novel synthetic derivative of α-Tocopheryl Succinate, induced apoptosis via production of reactive oxygen species (ROS). When used in combination with doxorubicin, lower doses of VCPA sensitized human gastric cancer cells to DOX-induced apoptosis. The DOX/VCPA combination treatment caused an imbalance in the ratio of Bcl-2 to Bax and induced a lethal mitochondrial dysfunction. MAPKs were also activated in response to the DOX/VCPA treatment but played a protective role in DOX-induced cell death. In vivo studies further confirmed the sensitizing effect of VCPA. Combining DOX with VCPA markedly inhibited tumor growth in a tumor xenograft model of human gastric cancer. Taken together, our study revealed that VCPA, through increased ROS production, could synergize with DOX and circumvent DOX resistance in human gastric cancer cells. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. [Sodium valproate enhances doxorubicin cytotoxicity in breast cancer cells in vitro].

    Science.gov (United States)

    Tong, Xu-Hui; Zheng, Chao; Jiang, Guo-Jun; Dong, Shu-Ying

    2015-01-01

    To investigate the effect of sodium valproate, a histone deacetylase inhibitor, on the cytotoxicity of doxorubicin in breast cancer cells. Western blotting was used to assess Cx43 protein expression in breast cancer Hs578T cells exposed to doxorubicin and sodium valproate. MTT assay was used to determine the cytotoxicity of doxorubicin; annexin V/PI double staining and Hochest 33258 fluorescence staining were employed to detect doxorubicin-induced early and late apoptosis, respectively. Western blotting showed that sodium valproate significantly increased Cx43 protein expression in Hs578T cells (P/0.01). The cells exposed to both sodium valproate and doxorubicin showed significantly lowered cell viability compared with the cells exposed to doxorubicin alone (P/0.01). Exposure to both sodium valproate and doxorubicin resulted in significantly increased early and late cell apoptosis rate compared with doxorubicin treatment alone (P/0.01). sodium valproate can significantly enhance the cytotoxicity of doxorubicin and increase doxorubicin-induced apoptosis in breast cancer cells in vitro possibly by enhancing the gap junction function.

  2. Randomized parallel study of doxorubicin plus paclitaxel and doxorubicin plus cyclophosphamide as neoadjuvant treatment of patients with breast cancer.

    Science.gov (United States)

    Diéras, Véronique; Fumoleau, Pierre; Romieu, Gilles; Tubiana-Hulin, Michèle; Namer, Moïse; Mauriac, Louis; Guastalla, Jean-Paul; Pujade-Lauraine, Eric; Kerbrat, Pierre; Maillart, Philippe; Pénault-Llorca, Frédérique; Buyse, Marc; Pouillart, Pierre

    2004-12-15

    This randomized, noncomparative, parallel-group study was designed to evaluate the pathologic complete response (pCR) rate of combined doxorubicin plus paclitaxel (AP) and doxorubicin plus cyclophosphamide (AC) as neoadjuvant chemotherapy in patients with previously untreated breast cancer who were unsuitable for conservative surgery. A total of 200 patients with T2-3, N0-1, M0 disease were randomly assigned in a 2:1 ratio to receive preoperative chemotherapy with either doxorubicin 60 mg/m(2) plus paclitaxel 200 mg/m(2) as a 3-hour infusion (AP) or doxorubicin 60 mg/m(2) plus cyclophosphamide 600 mg/m(2) (AC) every 3 weeks for 4 courses followed by surgery. A pCR (eradication of invasive carcinoma in tumor and in axillary lymph nodes) was found in 16% and 10% of patients in the AP and AC arms, respectively, by study center pathologists, and in 8% and 6% of patients, respectively, by independent pathologists. Patients with pCRs tended to have unifocal disease, tumors with negative hormonal receptor status, and less differentiation (Scarff, Bloom, and Richardson scale grade 3). Breast-conserving surgery was performed in 58% and 45% of patients in the AP and AC arms, respectively. An objective clinical response was achieved in 89% of patients in the AP arm and 70% in the AC arm. At a median follow-up of 31 months, disease-free survival (DFS) was higher in patients who reached pCR versus those without pCR (91% v 70%). The encouraging pathologic and clinical responses of patients with breast cancer after neoadjuvant chemotherapy with doxorubicin plus paclitaxel warrant additional investigation of paclitaxel in the neoadjuvant setting of breast cancer management.

  3. ZnO nanofluids for the improved cytotoxicity and cellular uptake of doxorubicin

    Directory of Open Access Journals (Sweden)

    Safoura Soleymani

    2018-01-01

    Full Text Available Objective(s: Combination anticancer therapy holds promise for improving the therapeutic efficacy of chemotherapy drugs such as doxorubicin (DOX as well as decreasing their dose-limiting side effects. Overcoming the side effects of doxorubicin (DOX is a major challenge to the effective treatment of cancer. Zinc oxide nanoparticles (ZnO NPs are emerging as potent tools for a wide variety of biomedical applications. The aim of this study was to develop a combinatorial approach for enhancing the anticancer efficacy and cellular uptake of DOX. Materials and Methods: ZnO NPs were synthesized by the solvothermal method and were characterized by X-ray diffraction (XRD, dynamic light scattering (DLS and transmission electron microscopy (TEM. ZnO NPs were dispersed in 10% bovine serum albumin (BSA and the cytotoxic effect of the resulting ZnO nanofluids was evaluated alone and in combination with DOX on DU145 cells. The influence of ZnO nanofluids on the cellular uptake of DOX and DOX-induced catalase mRNA expression were investigated by fluorescence microscopy and semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR, respectively. Results: The MTT results revealed that ZnO nanofluids decreased the cell viability of DU145 cells in a timeand dose-dependent manner. Simultaneous combination treatment of DOX and ZnO nanofluid showed a significant increase in anticancer activity and the cellular uptake of DOX compared to DOX alone. Also, a time-dependent reduction of catalase mRNA expression was observed in the cells treated with ZnO nanofluids and DOX, alone and in combination with each other. Conclusion: These results indicate the role of ZnO nanofluid as a growth-inhibitory agent and a drug delivery system for DOX in DU145 cells. Thus, ZnO nanofluid could be a candidate for combination chemotherapy.

  4. Inhibition of the mitochondrial pyrimidine biosynthesis enzyme dihydroorotate dehydrogenase by doxorubicin and brequinar sensitizes cancer cells to TRAIL-induced apoptosis.

    Science.gov (United States)

    He, T; Haapa-Paananen, S; Kaminskyy, V O; Kohonen, P; Fey, V; Zhivotovsky, B; Kallioniemi, O; Perälä, M

    2014-07-03

    Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising agent in selectively killing tumor cells. However, TRAIL monotherapy has not been successful as many cancer cells are resistant to TRAIL. Chemotherapeutic agents, such as doxorubicin have been shown to act synergistically with TRAIL, but the exact mechanisms of actions are poorly understood. In this study, we performed high-throughput small interfering RNA screening and genome-wide gene expression profiling on doxorubicin-treated U1690 cells to explore novel mechanisms underlying doxorubicin-TRAIL synergy. The screening and expression profiling results were integrated and dihydroorotate dehydrogenase (DHODH) was identified as a potential candidate. DHODH is the rate-limiting enzyme in the pyrimidine synthesis pathway, and its expression was downregulated by doxorubicin. We demonstrated that silencing of DHODH or inhibition of DHODH activity by brequinar dramatically increased the sensitivity of U1690 cells to TRAIL-induced apoptosis both in 2D and 3D cultures, and was accompanied by downregulation of c-FLIPL as well as by mitochondrial depolarization. In addition, uridine, an end product of the pyrimidine synthesis pathway was able to rescue the sensitization effects initiated by both brequinar and doxorubicin. Furthermore, several other cancer cell lines, LNCaP, MCF-7 and HT-29 were also shown to be sensitized to TRAIL by brequinar. Taken together, our findings have identified a novel protein target and its inhibitor, brequinar, as a potential agent in TRAIL-based combinatorial cancer therapy and highlighted for the first time the importance of mitochondrial DHODH enzyme and pyrimidine pathway in mediating TRAIL sensitization in cancer cells.

  5. MDR Gene Expression Analysis of Six Drug-Resistant Ovarian Cancer Cell Lines

    Directory of Open Access Journals (Sweden)

    Radosław Januchowski

    2013-01-01

    and protein levels. Cell lines resistant to agents used in ovarian cancer treatment remained sensitive to methotrexate. The main mechanisms of drug resistance were due to P-gp expression in the doxorubicin, vincristine, and paclitaxel resistant cell lines and BCRP expression in the topotecan resistant cell line.

  6. Controlled Release of Doxorubicin from Doxorubicin/γ-Polyglutamic Acid Ionic Complex

    Directory of Open Access Journals (Sweden)

    Bhavik Manocha

    2010-01-01

    Full Text Available Formation of drug/polymer complexes through ionic interactions has proven to be very effective for the controlled release of drugs. The stability of such drug/polymer ionic complexes can be greatly influenced by solution pH and ionic strength. The aim of the current work was to evaluate the potential of γ-polyglutamic acid (γ-PGA as a carrier for the anticancer drug, Doxorubicin (DOX. We investigated the formation of ionic complexes between γ-PGA and DOX using scanning electron microscopy, spectroscopy, thermal analysis, and X-ray diffraction. Our studies demonstrate that DOX specifically interacts with γ-PGA forming random colloidal aggregates and results in almost 100% complexation efficiency. In vitro drug release studies illustrated that these complexes were relatively stable at neutral pH but dissociates slowly under acidic pH environments, facilitating a pH-triggered release of DOX from the complex. Hydrolytic degradation of γ-PGA and DOX/γ-PGA complex was also evaluated in physiological buffer. In conclusion, these studies clearly showed the feasibility of γ-PGA to associate cationic drug such as DOX and that is may serve as a new drug carrier for the controlled release of DOX in malignant tissues.

  7. Reverse mortgages.

    Science.gov (United States)

    Farnesi, D

    1995-09-01

    Elders and their families are often caught in a financial bind when it comes to paying for much-needed home care services. Reverse mortgages may offer a solution to elderly home care clients who own their homes but have a limited income with which to maintain their independence.

  8. Reversible Computing

    Science.gov (United States)

    1980-02-01

    will have been introduced. 9. Reversible celular autemata We shall assume the reader to have some familiarity with the concept of cel- lular...10003 Mr. Kin B. Thcmpson 1 copy Technical Director Information Systems Divisia.i Naval Research Laboratory (OP-91T) Technical Information Division

  9. Identifying a Resistance Determinant for the Antimitotic Natural Products Disorazole C1 and A1S⃞

    Science.gov (United States)

    Reese, Celeste E.; Vogt, Andreas; Vollmer, Laura L.; Kitchens, Carolyn A.; Günther, Eckhard; Graham, Thomas H.; Hopkins, Chad D.; Wipf, Peter

    2010-01-01

    Disorazoles are macrocyclic polyketides first isolated from the fermentation broth of the myxobacterium Sorangium cellulosum. Both the major fermentation product disorazole A1 and its much rarer companion disorazole C1 exhibit potent cytotoxic activity against many human tumor cells. Furthermore, the disorazoles appear to bind tubulin uniquely among known antimitotic agents, promoting apoptosis or premature senescence. It is uncertain what conveys tumor cell sensitivity to these complex natural products. Therefore, we generated and characterized human tumor cells resistant to disorazole C1. Resistant cells proved exceedingly difficult to generate and required single step mutagenesis with chronic stepwise exposure to increasing concentrations of disorazole C1. Compared with wild-type HeLa cells, disorazole C1-resistant HeLa/DZR cells were 34- and 8-fold resistant to disorazole C1 and disorazole A1 growth inhibition, respectively. HeLa/DZR cells were also remarkably cross-resistant to vinblastine (280-fold), paclitaxel (2400-fold), and doxorubicin (47-fold) but not cisplatin, suggesting a multidrug-resistant phenotype. Supporting this hypothesis, MCF7/MDR cells were 10-fold cross-resistant to disorazole C1. HeLa/DZR disorazole resistance was not durable in the absence of chronic compound exposure. Verapamil reversed HeLa/DZR resistance to disorazole C1 and disorazole A1. Moreover, HeLa/DZR cells expressed elevated levels of the drug resistance ATP-binding cassette ABCB1 transporter. Loss of ABCB1 by incubation with short interfering RNA restored sensitivity to the disorazoles. Thus, the multidrug resistance transporter ABCB1 can affect the cytotoxicity of both disorazole C1 and A1. Disorazole C1, however, retained activity against cells resistant against the clinically used microtubule-stabilizing agent epothilone B. PMID:20008956

  10. 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.

  11. Nucleoside reverse transcriptase inhibitor resistance mutations associated with first-line stavudine-containing antiretroviral therapy: programmatic implications for countries phasing out stavudine

    NARCIS (Netherlands)

    Tang, Michele W.; Rhee, Soo-Yon; Bertagnolio, Silvia; Ford, Nathan; Holmes, Susan; Sigaloff, Kim C.; Hamers, Raph L.; Rinke de Wit, Tobias F.; Fleury, Herve J.; Kanki, Phyllis J.; Ruxrungtham, Kiat; Hawkins, Claudia A.; Wallis, Carole L.; Stevens, Wendy; van Zyl, Gert U.; Manosuthi, Weerawat; Hosseinipour, Mina C.; Ngo-Giang-Huong, Nicole; Belec, Laurent; Peeters, Martine; Aghokeng, Avelin; Bunupuradah, Torsak; Burda, Sherri; Cane, Patricia; Cappelli, Giulia; Charpentier, Charlotte; Dagnra, Anoumou Y.; Deshpande, Alaka K.; El-Katib, Ziad; Eshleman, Susan H.; Fokam, Joseph; Gody, Jean-Chrysostome; Katzenstein, David; Koyalta, Donato D.; Kumwenda, Johnstone J.; Lallemant, Marc; Lynen, Lutgarde; Marconi, Vincent C.; Margot, Nicolas A.; Moussa, Sandrine; Ndung'u, Thumbi; Nyambi, Phillipe N.; Orrell, Catherine; Schapiro, Jonathan M.; Schuurman, Rob; Sirivichayakul, Sunee; Smith, Davey; Zolfo, Maria; Jordan, Michael R.; Shafer, Robert W.

    2013-01-01

    The World Health Organization Antiretroviral Treatment Guidelines recommend phasing-out stavudine because of its risk of long-term toxicity. There are two mutational pathways of stavudine resistance with different implications for zidovudine and tenofovir cross-resistance, the primary candidates for

  12. Epigallocatechin-3-gallate potentiates the effect of curcumin in inducing growth inhibition and apoptosis of resistant breast cancer cells.

    Science.gov (United States)

    Wang, Shengpeng; Chen, Ruie; Zhong, Zhangfeng; Shi, Zhi; Chen, Meiwan; Wang, Yitao

    2014-01-01

    Drug resistance remains an on-going challenge in breast cancer chemotherapy. Combination of two or more drugs is an effective strategy to access context-specific multiple targets and overcome undesirable toxicity that is almost inevitable in single-drug chemotherapy. Many plant food-derived polyphenolic compounds have been proven to modulate many key factors responsible for cancer drug resistance, which makes them a promising group of low toxicity candidates for reversing cancer resistance. In this study, we analyzed the combination effect of two chemopreventive polyphenols, curcumin (Cur) and epigallocatechin-3-gallate (EGCG), in combating resistant breast cancer. Our present results showed that EGCG significantly enhanced the growth inhibition and apoptosis in both doxorubicin (DOX)-sensitive and resistant MCF-7 cells induced by Cur. The mechanism may be related to the further activation of caspase-dependent apoptotic signaling pathways and the enhanced cellular incorporation of Cur by inhibiting P-glycoprotein (P-gp) pump function. Moreover, Cur and EGCG in combination could enhance the toxicity of DOX and increase the intracellular level of DOX in resistant MCF-7 cells. Our findings with this practical combination of Cur and EGCG encourage us to move on to a promising strategy for successful treatment of human breast cancer resistance by combining two low-toxic chemotherapeutic agents from diet.

  13. Spatial and Reversal Learning in the Morris Water Maze Are Largely Resistant to Six Hours of REM Sleep Deprivation Following Training

    Science.gov (United States)

    Walsh, Christine M.; Booth, Victoria; Poe, Gina R.

    2011-01-01

    This first test of the role of REM (rapid eye movement) sleep in reversal spatial learning is also the first attempt to replicate a much cited pair of papers reporting that REM sleep deprivation impairs the consolidation of initial spatial learning in the Morris water maze. We hypothesized that REM sleep deprivation following training would impair…

  14. The monoamine oxidase A inhibitor clorgyline is a broad-spectrum inhibitor of fungal ABC and MFS transporter efflux pump activities which reverses the azole resistance of Candida albicans and Candida glabrata clinical isolates.

    Science.gov (United States)

    Holmes, Ann R; Keniya, Mikhail V; Ivnitski-Steele, Irena; Monk, Brian C; Lamping, Erwin; Sklar, Larry A; Cannon, Richard D

    2012-03-01

    Resistance to the commonly used azole antifungal fluconazole (FLC) can develop due to overexpression of ATP-binding cassette (ABC) and major facilitator superfamily (MFS) plasma membrane transporters. An approach to overcoming this resistance is to identify inhibitors of these efflux pumps. We have developed a pump assay suitable for high-throughput screening (HTS) that uses recombinant Saccharomyces cerevisiae strains hyperexpressing individual transporters from the opportunistic fungal pathogen Candida albicans. The recombinant strains possess greater resistance to azoles and other pump substrates than the parental host strain. A flow cytometry-based HTS, which measured increased intracellular retention of the fluorescent pump substrate rhodamine 6G (R6G) within yeast cells, was used to screen the Prestwick Chemical Library (PCL) of 1,200 marketed drugs. Nine compounds were identified as hits, and the monoamine oxidase A inhibitor (MAOI) clorgyline was identified as an inhibitor of two C. albicans ABC efflux pumps, CaCdr1p and CaCdr2p. Secondary in vitro assays confirmed inhibition of pump-mediated efflux by clorgyline. Clorgyline also reversed the FLC resistance of S. cerevisiae strains expressing other individual fungal ABC transporters (Candida glabrata Cdr1p or Candida krusei Abc1p) or the C. albicans MFS transporter Mdr1p. Recombinant strains were also chemosensitized by clorgyline to other azoles (itraconazole and miconazole). Importantly, clorgyline showed synergy with FLC against FLC-resistant C. albicans clinical isolates and a C. glabrata strain and inhibited R6G efflux from a FLC-resistant C. albicans clinical isolate. Clorgyline is a novel broad-spectrum inhibitor of two classes of fungal efflux pumps that acts synergistically with azoles against azole-resistant C. albicans and C. glabrata strains.

  15. Histopathological effects of doxorubicin on pancreas in male albino rats

    Directory of Open Access Journals (Sweden)

    I.A. Ali

    2015-06-01

    Full Text Available The aim of this study was to investigate the histopathological side effects of doxorubicin on pancreas tissue in male albino rats Rattus norvegicus. This study were used 55 adult rats (2.5-3.5 month of age. The rats divided into two groups, the first group include (35 rats. The second group were (20 rats. Microscopial examination of pancreas lesion demonstrated oedema around the acini, swelling of the epithelial cells of acini, occurance of cystic fibrosis (mucoviscidosis at the concentration of (4,5 mg/kg of body weight ,occurrence of small islets that form of few cells and exocrine-endocrine transformation. There were thickness in the walls of blood vessels, thrombus, congestion of blood vessels, we conclude, that doxorubicin had histopathological effect on pancreas in sub-acute doses more than chronic doses.

  16. Fluorescence properties of several chemotherapy drugs: doxorubicin, paclitaxel and bleomycin

    OpenAIRE

    Motlagh, Najme Sadat Hosseini; Parvin, Parviz; Ghasemi, Fatemah; Atyabi, Fatemeh

    2016-01-01

    Several chemo-drugs act as the biocompatible fluorophores. Here, the laser induced fluorescence (LIF) properties of doxorubicin, paclitaxel and bleomycin are investigated. The absorption lines mostly lie over UV range according to the UV-VIS spectra. Therefore, a single XeCl laser provokes the desired transitions of the chemo-drugs of interest at 308 nm. It is shown that LIF spectra are strongly dependent on the fluorophore concentration giving rise to the sensible red shift. This happens whe...

  17. Pegylated liposomal doxorubicin in the management of ovarian cancer

    Directory of Open Access Journals (Sweden)

    Gabriella Ferrandina

    2010-09-01

    Full Text Available Gabriella Ferrandina1,2, Giacomo Corrado1, Angelo Licameli1, Domenica Lorusso2, Gilda Fuoco1, Salvatore Pisconti3, Giovanni Scambia2 1Gynecologic Oncology Unit, Department of Oncology, Catholic University of Campobasso, Campobasso, Italy; 2Gynecologic Oncology Unit, Catholic University of Rome, Rome, Italy; 3Salvatore Pisconti, Oncology Unit, Taranto Hospital, Taranto, Italy Abstract: Among the pharmaceutical options available for treatment of ovarian cancer, much attention has been progressively focused on pegylated liposomal doxorubicin (PLD, whose unique formulation, which entraps conventional doxorubicin in a bilayer lipidic sphere ­surrounded by a polyethylene glycol layer, prolongs the persistence of the drug in the ­circulation and potentiates intratumor drug accumulation. These properties enable this drug to sustain its very favorable toxicity profile and to be used safely in combination with other drugs. PLD has been already approved for treatment of advanced ovarian cancer patients failing first-line platinum-based treatment. Moreover, phase III trials have been already completed, and results are eagerly awaited, which hopefully will expand the range of PLD clinical application in this neoplasia both in front-line treatment, and in the salvage setting in combination with other drugs. Moreover, attempts are continuing to enable this drug to be combined with novel cytotoxic drugs and target-based agents. This review aims at summarizing the available evidence and the new perspectives for the clinical role of PLD in the management of patients with epithelial ovarian cancer.Keywords: pegylated liposomal doxorubicin, ovarian cancer, clinical trials

  18. Modulator effects of meloxicam against doxorubicin-induced nephrotoxicity in mice.

    Science.gov (United States)

    Hassan, Memy H; Ghobara, Mohamed; Abd-Allah, Gamil M

    2014-08-01

    Doxorubicin-induced renal toxicity overshadows its anticancer effectiveness. This study is aimed at assessing the possible modulator effects of meloxicam, a cyclooxigenase-2 inhibitor, on doxorubicin-induced nephrotoxicity in mice and exploring some of the modulator mechanisms. Forty male mice were divided for treatment, for 2 weeks, with saline, meloxicam (daily), doxorubicin (twice/week), or both meloxicam and doxorubicin. Doxorubicin induced a significant increase in relative kidney weight to body weight, kidney lipid perooxidation, plasma levels of interleukin-6 and tumor necrosis factor-α, kidney caspase-3 activity, and kidney prostaglandin E2 (PGE2) content. Doxorubicin disturbed kidney histology, abrogated renal function tests (serum creatinine, uric acid, and blood urea nitrogen), induced a significant decrease in antioxidant enzyme activities (superoxide dismutase, glutathione peroxidase, and catalase) and reduced glutathione (GSH) content. The administration of meloxicam with doxorubicin mitigated all doxorubicin-disturbed parameters. Meloxicam ameliorated doxorubicin-induced renal injury via inhibition of inflammatory PGE2, inflammatory cytokines, caspase-3 activity, antioxidant effect, and free radical scavenging activity. © 2014 Wiley Periodicals, Inc.

  19. MicroRNA-208a Silencing Attenuates Doxorubicin Induced Myocyte Apoptosis and Cardiac Dysfunction

    Directory of Open Access Journals (Sweden)

    Hasahya Tony

    2015-01-01

    Full Text Available Aims. GATA4 depletion is a distinct mechanism by which doxorubicin leads to cardiomyocyte apoptosis, and preservation of GATA4 mitigates doxorubicin induced myocyte apoptosis and cardiac dysfunction. We investigated a novel approach of attenuating doxorubicin induced cardiac toxicity by silencing miR-208a, a heart specific microRNA known to target GATA4. Methods and Results. Eight-week-old female Balb/C mice were randomly assigned to sham, antagomir, and control groups. Antagomir group were pretreated with miR-208a antagomir 4 days before doxorubicin administration. At day 0, control and antagomir groups received 20 mg/kg of doxorubicin, while sham mice received phosphate buffered solution. Echocardiography was done at day 7, after which animals were sacrificed and hearts harvested and assessed for apoptosis and expression of miR-208a, GATA4, and BCL-2. Doxorubicin significantly upregulated miR-208a, downregulated GATA4, and increased myocyte apoptosis, with resulting decrease in cardiac function. In contrast, therapeutic silencing of miR-208a salvaged GATA4 and BCL-2 and decreased apoptosis, with improvement in cardiac function. Conclusion. Doxorubicin upregulates miR-208a and promotes cardiomyocyte apoptosis, while therapeutic silencing of miR-208a attenuates doxorubicin induced myocyte apoptosis with subsequent improvement in cardiac function. These novel results highlight the therapeutic potential of targeting miR-208a to prevent doxorubicin cardiotoxicity.

  20. Human colon cancer HT-29 cell death responses to doxorubicin and Morus Alba leaves flavonoid extract.

    Science.gov (United States)

    Fallah, S; Karimi, A; Panahi, G; Gerayesh Nejad, S; Fadaei, R; Seifi, M

    2016-03-31

    The mechanistic basis for the biological properties of Morus alba flavonoid extract (MFE) and chemotherapy drug of doxorubicin on human colon cancer HT-29 cell line death are unknown. The effect of doxorubicin and flavonoid extract on colon cancer HT-29 cell line death and identification of APC gene expression and PARP concentration of HT-29 cell line were investigated. The results showed that flavonoid extract and doxorubicin induce a dose dependent cell death in HT-29 cell line. MFE and doxorubicin exert a cytotoxic effect on human colon cancer HT-29 cell line by probably promoting or induction of apoptosis.

  1. A rapid method for simultaneous detection of phenotypic resistance to inhibitors of protease and reverse transcriptase in recombinant human immunodeficiency virus type 1 isolates from patients treated with antiretroviral drugs.

    Science.gov (United States)

    Hertogs, K; de Béthune, M P; Miller, V; Ivens, T; Schel, P; Van Cauwenberge, A; Van Den Eynde, C; Van Gerwen, V; Azijn, H; Van Houtte, M; Peeters, F; Staszewski, S; Conant, M; Bloor, S; Kemp, S; Larder, B; Pauwels, R

    1998-02-01

    Combination therapy with protease (PR) and reverse transcriptase (RT) inhibitors can efficiently suppress human immunodeficiency virus (HIV) replication, but the emergence of drug-resistant variants correlates strongly with therapeutic failure. Here we describe a new method for high-throughput analysis of clinical samples that permits the simultaneous detection of HIV type 1 (HIV-1) phenotypic resistance to both RT and PR inhibitors by means of recombinant virus assay technology. HIV-1 RNA is extracted from plasma samples, and a 2.2-kb fragment containing the entire HIV-1 PR- and RT-coding sequence is amplified by nested reverse transcription-PCR. The pool of PR-RT-coding sequences is then cotransfected into CD4+ T lymphocytes (MT4) with the pGEMT3deltaPRT plasmid from which most of the PR (codons 10 to 99) and RT (codons 1 to 482) sequences are deleted. Homologous recombination leads to the generation of chimeric viruses containing PR- and RT-coding sequences derived from HIV-1 RNA in plasma. The susceptibilities of the chimeric viruses to all currently available RT and/or PR inhibitors is determined by an MT4 cell-3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide-based cell viability assay in an automated system that allows high sample throughput. The profile of resistance to all RT and PR inhibitors is displayed graphically in a single PR-RT-Antivirogram. This assay system facilitates the rapid large-scale phenotypic resistance determinations for all RT and PR inhibitors in one standardized assay.

  2. Fullerenol/doxorubicin nanocomposite mitigates acute oxidative stress and modulates apoptosis in myocardial tissue

    Science.gov (United States)

    Seke, Mariana; Petrovic, Danijela; Djordjevic, Aleksandar; Jovic, Danica; Labudovic Borovic, Milica; Kanacki, Zdenko; Jankovic, Milan

    2016-12-01

    Fullerenol (C60(OH)24) is present in aqueous solutions in the form of polyanion nanoparticles with particles’ size distribution within the range from 15 to 42 nm. In this research it is assumed that these features could enable fullerenol nanoparticles (FNPs) to bind positively charged molecules like doxorubicin (DOX) and serve as drug carriers. Considering this, fullerenol/doxorubicin nanocomposite (FNP/DOX) is formed and characterized by ultra-performance liquid chromatography tandem mass spectrometry, dynamic light scattering, atomic force microscopy and transmission electron microscopy. Measurements have shown that DOX did not significantly affect particle size (23 nm). It is also assumed that FNP/DOX could reduce the acute cardiotoxic effects of DOX in vivo (Wistar rats treated i.p.). In this study, quantitative real time polymerase chain reaction results have shown that treatment with DOX alone caused significant increase in mRNA levels of catalase (p < 0.05) enzyme indicating the presence of oxidative stress. This effect is significantly reduced by the treatment with FNP/DOX (p < 0.05). Furthermore, mRNA levels of antiapoptotic enzyme (Bcl-2) are significantly increased (p < 0.05) in all treated groups, particularly where FNP/DOX was applied, suggesting cell resistance to apoptosis. Moreover, ultrastructural analysis has shown the absence of myelin figures within the mitochondria in the heart tissue with FNP/DOX treatment, indicating reduction of oxidative stress. Hence, our results have implied that FNP/DOX is generally less harmful to the heart compared to DOX.

  3. Recombinant TIMP-1-GPI inhibits growth of fibrosarcoma and enhances tumor sensitivity to doxorubicin.

    Science.gov (United States)

    Bao, Q; Niess, H; Djafarzadeh, R; Zhao, Y; Schwarz, B; Angele, M K; Jauch, K-W; Nelson, P J; Bruns, C J

    2014-09-01

    Fibrosarcomas show a high incidence of recurrence and general resistance to apoptosis. Limiting tumor regrowth and increasing their sensitivity to chemotherapy and apoptosis represent key issues in developing more effective treatments of these tumors. Tissue inhibitor of metalloproteinase 1 (TIMP-1) broadly blocks matrix metalloproteinase (MMP) activity and can moderate tumor growth and metastasis. We previously described generation of a recombinant fusion protein linking TIMP-1 to glycosylphophatidylinositol (GPI) anchor (TIMP-1-GPI) that efficiently directs the inhibitor to cell surfaces. In the present report, we examined the effect of TIMP-1-GPI treatment on fibrosarcoma biology. Exogenously applied TIMP-1-GPI efficiently incorporated into surface membranes of human HT1080 fibrosarcoma cells. It inhibited their proliferation, migration, suppressed cancer cell clone formation, and enhanced apoptosis. Doxorubicin, the standard chemotherapeutic drug for fibrosarcoma, was tested alone or in combination with TIMP-1-GPI. In parallel, the influence of treatment on HT1080 side population cells (exhibiting tumor stem cell-like characteristics) was investigated using Hoechst 33342 staining. The sequential combination of TIMP-1-GPI and doxorubicin showed more than additive effects on apoptosis, while TIMP-1-GPI treatment alone effectively decreased "stem-cell like" side population cells of HT1080. TIMP-1-GPI treatment was validated using HT1080 fibrosarcoma murine xenografts. Growing tumors treated with repeated local injections of TIMP-1-GPI showed dramatically inhibited fibrosarcoma growth and reduced angiogenesis. Intraoperative peritumoral application of GPI-anchored TIMP-1 as an adjuvant to surgery may help maintain tumor control by targeting microscopic residual fibrosarcoma cells and increasing their sensitivity to chemotherapy.

  4. Paclitaxel and doxorubicin in metastatic breast cancer

    DEFF Research Database (Denmark)

    Gehl, J; Boesgaard, M; Paaske, T

    1996-01-01

    For the past decades the anthracyclines have been regarded as among the most active drugs for the treatment of metastatic breast cancer. However, the 5-year survival rate in patients with stage IV breast cancer continues to be below 20%, and new active drugs and drug combinations clearly must...... be explored. Paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ) has been demonstrated to be highly effective in treating patients with advanced breast cancer, including those with anthracycline-resistant breast cancer, a fact that has led to efforts to combine paclitaxel and anthracyclines...

  5. (188)Re-Liposome Can Induce Mitochondrial Autophagy and Reverse Drug Resistance for Ovarian Cancer: From Bench Evidence to Preliminary Clinical Proof-of-Concept.

    Science.gov (United States)

    Chang, Chia-Ming; Lan, Keng-Li; Huang, Wen-Sheng; Lee, Yi-Jang; Lee, Te-Wei; Chang, Chih-Hsien; Chuang, Chi-Mu

    2017-04-25

    Despite standard treatment, about 70% of ovarian cancer will recur. Cancer stem cells (CSCs) have been implicated in the drug-resistance mechanism. Several drug resistance mechanisms have been proposed, and among these, autophagy plays a crucial role for the maintenance and tumorigenicity of CSCs. Compared to their differentiated counterparts, CSCs have been demonstrated to display a significantly higher level of autophagy flux. Moreover, mitophagy, a specific type of autophagy that selectively degrades excessive or damaged mitochondria, is shown to contribute to cancer progression and recurrence in several types of tumors. Nanomedicine has been shown to tackle the CSCs problem by overcoming drug resistance. In this work, we developed a nanomedicine, (188)Re-liposome, which was demonstrated to target autophagy and mitophagy in the tumor microenvironment. Of note, the inhibition of autophagy and mitophagy could lead to significant tumor inhibition in two xenograft animal models. Lastly, we presented two cases of recurrent ovarian cancer, both in drug resistance status that received a level I dose from a phase I clinical trial. Both cases developing drug resistance showed drug sensitivity to (188)Re-liposome. These results suggest that inhibition of autophagy and mitophagy by a nanomedicine may be a novel strategy to overcome drug resistance in ovarian cancer.

  6. 188Re-Liposome Can Induce Mitochondrial Autophagy and Reverse Drug Resistance for Ovarian Cancer: From Bench Evidence to Preliminary Clinical Proof-of-Concept

    Directory of Open Access Journals (Sweden)

    Chia-Ming Chang

    2017-04-01

    Full Text Available Despite standard treatment, about 70% of ovarian cancer will recur. Cancer stem cells (CSCs have been implicated in the drug-resistance mechanism. Several drug resistance mechanisms have been proposed, and among these, autophagy plays a crucial role for the maintenance and tumorigenicity of CSCs. Compared to their differentiated counterparts, CSCs have been demonstrated to display a significantly higher level of autophagy flux. Moreover, mitophagy, a specific type of autophagy that selectively degrades excessive or damaged mitochondria, is shown to contribute to cancer progression and recurrence in several types of tumors. Nanomedicine has been shown to tackle the CSCs problem by overcoming drug resistance. In this work, we developed a nanomedicine, 188Re-liposome, which was demonstrated to target autophagy and mitophagy in the tumor microenvironment. Of note, the inhibition of autophagy and mitophagy could lead to significant tumor inhibition in two xenograft animal models. Lastly, we presented two cases of recurrent ovarian cancer, both in drug resistance status that received a level I dose from a phase I clinical trial. Both cases developing drug resistance showed drug sensitivity to 188Re-liposome. These results suggest that inhibition of autophagy and mitophagy by a nanomedicine may be a novel strategy to overcome drug resistance in ovarian cancer.

  7. Grape seed procyanidin reversal of p-glycoprotein associated multi-drug resistance via down-regulation of NF-κB and MAPK/ERK mediated YB-1 activity in A2780/T cells.

    Directory of Open Access Journals (Sweden)

    Bo-xin Zhao

    Full Text Available The expression and function of P-glycoprotein (P-gp is associated with the phenotype of multi-drug resistance (MDR, leading chemotherapy failure of patients suffered with cancer. Grape seed procyanidin(GSP is a natural polyphenol supplement with anti-inflammatory effect. Present study assessed a new use of GSP on the MDR reversal activity and its possible molecular mechanisms in MDR1-overpressing paclitaxel resistant ovarian cancer cells. Our results showed GSP significantly enhanced the cytotoxicity of paclitaxel and adriamycin in paclitaxel resistant A2780/T cells but its parental A2780 cells. Furthermore, GSP strongly inhibited P-gp expression by blocking MDR1 gene transcription, as well as, increased the intracellular accumulation of the P-gp substrate rhodamine-123 in A2780/T cells. Nuclear factor-κB(NF-κB activity, IκB degradation level and NF-κB/p65 nuclear translocation induced by lipopolysaccharide (LPS and receptor activator for nuclear factor-κB ligand (RANKL were markedly inhibited by pre-treatment with GSP. Meanwhile, GSP inhibited MAPK/ERK pathway by decreasing the phosphorylation of ERK1/2, resulting in reduced the Y-box binding protein 1 (YB-1 activation with blocking its nuclear translocation. Moreover, the up-regulation of P-gp expression, the activation of AKT/NF-κB and MAPK/ERK pathway induced by LPS was attenuated by GSP administration. Compared with PDTC and U1026, inhibitor of NF-κB and MAPK/ERK respectively, GSP showed the same tendency of down-regulating NF-κB and MAPK/ERK mediated YB-1 activities. Thus, GSP reverses P-gp associated MDR by inhibiting the function and expression of P-gp through down-regulation of NF-κB activity and MAPK/ERK pathway mediated YB-1 nuclear translocation, offering insight into the mechanism of reversing MDR by natural polyphenol supplement compounds. GSP could be a new potential MDR reversal agent used for combination therapy with chemotherapeutics in clinic.

  8. STAT1 pathway mediates amplification of metastatic potential and resistance to therapy.

    Directory of Open Access Journals (Sweden)

    Nikolai N Khodarev

    Full Text Available BACKGROUND: Traditionally IFN/STAT1 signaling is connected with an anti-viral response and pro-apoptotic tumor-suppressor functions. Emerging functions of a constitutively activated IFN/STAT1 pathway suggest an association with an aggressive tumor phenotype. We hypothesized that tumor clones that constitutively overexpress this pathway are preferentially selected by the host microenvironment due to a resistance to STAT1-dependent cytotoxicity and demonstrate increased metastatic ability combined with increased resistance to genotoxic stress. METHODOLOGY/PRINCIPAL FINDINGS: Here we report that clones of B16F1 tumors grown in the lungs of syngeneic C57BL/6 mice demonstrate variable transcriptional levels of IFN/STAT1 pathway expression. Tumor cells that constitutively overexpress the IFN/STAT1 pathway (STAT1(H genotype are selected by the lung microenvironment. STAT1(H tumor cells also demonstrate resistance to IFN-gamma (IFNgamma, ionizing radiation (IR, and doxorubicin relative to parental B16F1 and low expressors of the IFN/STAT1 pathway (STAT1(L genotype. Stable knockdown of STAT1 reversed the aggressive phenotype and decreased both lung colonization and resistance to genotoxic stress. CONCLUSIONS: Our results identify a pathway activated by tumor-stromal interactions thereby selecting for pro-metastatic and therapy-resistant tumor clones. New therapies targeted against the IFN/STAT1 signaling pathway may provide an effective strategy to treat or sensitize aggressive tumor clones to conventional cancer therapies and potentially prevent distant organ colonization.

  9. Label-free recognition of drug resistance via impedimetric screening of breast cancer cells.

    Directory of Open Access Journals (Sweden)

    Bilge Eker

    Full Text Available We present a novel study on label-free recognition and distinction of drug resistant breast cancer cells (MCF-7 DOX from their parental cells (MCF-7 WT via impedimetric measurements. Drug resistant cells exhibited significant differences in their dielectric properties compared to wild-type cells, exerting much higher extracellular resistance (Rextra . Immunostaining revealed that MCF-7 DOX cells gained a much denser F-actin network upon acquiring drug resistance indicating that remodeling of actin cytoskeleton is probably the reason behind higher Rextra , providing stronger cell architecture. Moreover, having exposed both cell types to doxorubicin, we were able to distinguish these two phenotypes based on their substantially different drug response. Interestingly, impedimetric measurements identified a concentration-dependent and reversible increase in cell stiffness in the presence of low non-lethal drug doses. Combined with a profound frequency analysis, these findings enabled distinguishing distinct cellular responses during drug exposure within four concentration ranges without using any labeling. Overall, this study highlights the possibility to differentiate drug resistant phenotypes from their parental cells and to assess their drug response by using microelectrodes, offering direct, real-time and noninvasive measurements of cell dependent parameters under drug exposure, hence providing a promising step for personalized medicine applications such as evaluation of the disease progress and optimization of the drug treatment of a patient during chemotherapy.

  10. Customized laboratory TLR4 and TLR2 detection method from peripheral human blood for early detection of doxorubicin-induced cardiotoxicity.

    Science.gov (United States)

    Pop-Moldovan, A L; Trofenciuc, N-M; Dărăbanţiu, D A; Precup, C; Branea, H; Christodorescu, R; Puşchiţă, M

    2017-05-01

    Cancer treatments can have significant cardiovascular adverse effects that can cause cardiomyopathy and heart failure with reduced survival benefit and considerable decrease in the use of antineoplastic therapy. The purpose of this study is to assess the role of TLR2 and TLR4 gene expression as an early marker for the risk of doxorubicin-induced cardiomyopathy in correlation with early diastolic dysfunction in patients treated with doxorubicin. Our study included 25 consecutive patients who received treatment with doxorubicin for hematological malignancies (leukemia, lymphomas or multiple myeloma), aged 18-65 years, with a survival probability>6 months and with left ventricular ejection fraction>50%. Exclusion criteria consisted of the following: previous anthracycline therapy, previous radiotherapy, history of heart failure or chronic renal failure, atrial fibrillation, and pregnancy. In all patients, in fasting state, a blood sample was drawn for the assessment of TLR2 and TLR4 gene expression. Gene expression was assessed by quantitative reverse transcription PCR (qRT-PCR) using blood collection, RNA isolation, cDNA reverse transcription, qRT-PCR and quantification of the relative expression. At enrollment, all patients were evaluated clinically; an ECG and an echocardiography were performed. The average amount of gene expression units was 0.113 for TLR4 (range 0.059-0.753) and 0.218 for TLR2 (range 0.046-0.269). The mean mRNA extracted quantity was 113 571 ng/μl. As for the diastolic function parameters, criteria for diastolic dysfunction were present after 6 months in 16 patients (64%). In these patients, the mean values for TLR4 were 0.1198625 and for TLR2 were 0.16454 gene expression units. As for the diastolic function parameters, criteria for diastolic dysfunction were present after 6 months in 16 patients (64%). In these patients, the mean value for TLR2 was 0.30±0.19 and for TLR4 was 0.15±0.04. The corresponding values for the patients who did not

  11. Propofol ameliorates doxorubicin-induced oxidative stress and cellular apoptosis in rat cardiomyocytes

    Energy Technology Data Exchange (ETDEWEB)

    Lai, H.C. [Cardiovascular Center and Department of Anesthesiology, Taichung Veterans General Hospital, Taichung, Taiwan (China); Department of Medicine and Cardiovascular Research Center, National Yang-Ming University School of Medicine, Taipei, Taiwan (China); Yeh, Y.C. [Graduate Institute of Natural Healing Sciences, Nanhua University, Chiayi, Taiwan (China); Wang, L.C. [Cardiovascular Center and Department of Anesthesiology, Taichung Veterans General Hospital, Taichung, Taiwan (China); Ting, C.T.; Lee, W.L. [Cardiovascular Center and Department of Anesthesiology, Taichung Veterans General Hospital, Taichung, Taiwan (China); Department of Medicine and Cardiovascular Research Center, National Yang-Ming University School of Medicine, Taipei, Taiwan (China); Lee, H.W. [Cardiovascular Center and Department of Anesthesiology, Taichung Veterans General Hospital, Taichung, Taiwan (China); Wang, K.Y. [Cardiovascular Center and Department of Anesthesiology, Taichung Veterans General Hospital, Taichung, Taiwan (China); Department of Medicine, Chung-Shan Medical University, Taichung, Taiwan (China); Wu, A. [College of Biological Science, University of California, Davis (United States); Su, C.S. [Cardiovascular Center and Department of Anesthesiology, Taichung Veterans General Hospital, Taichung, Taiwan (China); Department of Medicine and Cardiovascular Research Center, National Yang-Ming University School of Medicine, Taipei, Taiwan (China); Liu, T.J., E-mail: trliu@vghtc.gov.tw [Cardiovascular Center and Department of Anesthesiology, Taichung Veterans General Hospital, Taichung, Taiwan (China); Department of Medicine and Cardiovascular Research Center, National Yang-Ming University School of Medicine, Taipei, Taiwan (China)

    2011-12-15

    Background: Propofol is an anesthetic with pluripotent cytoprotective properties against various extrinsic insults. This study was designed to examine whether this agent could also ameliorate the infamous toxicity of doxorubicin, a widely-used chemotherapeutic agent against a variety of cancer diseases, on myocardial cells. Methods: Cultured neonatal rat cardiomyocytes were administrated with vehicle, doxorubicin (1 {mu}M), propofol (1 {mu}M), or propofol plus doxorubicin (given 1 h post propofol). After 24 h, cells were harvested and specific analyses regarding oxidative/nitrative stress and cellular apoptosis were conducted. Results: Trypan blue exclusion and MTT assays disclosed that viability of cardiomyocytes was significantly reduced by doxorubicin. Contents of reactive oxygen and nitrogen species were increased and antioxidant enzymes SOD1, SOD2, and GPx were decreased in these doxorubicin-treated cells. Mitochondrial dehydrogenase activity and membrane potential were also depressed, along with activation of key effectors downstream of mitochondrion-dependent apoptotic signaling. Besides, abundance of p53 was elevated and cleavage of PKC-{delta} was induced in these myocardial cells. In contrast, all of the above oxidative, nitrative and pro-apoptotic events could be suppressed by propofol pretreatment. Conclusions: Propofol could extensively counteract oxidative/nitrative and multiple apoptotic effects of doxorubicin in the heart; hence, this anesthetic may serve as an adjuvant agent to assuage the untoward cardiac effects of doxorubicin in clinical application. -- Highlights: Black-Right-Pointing-Pointer We evaluate how propofol prevents doxorubicin-induced toxicity in cardiomyocytes. Black-Right-Pointing-Pointer Propofol reduces doxorubicin-imposed nitrative and oxidative stress. Black-Right-Pointing-Pointer Propofol suppresses mitochondrion-, p53- and PKC-related apoptotic signaling. Black-Right-Pointing-Pointer Propofol ameliorates apoptosis and

  12. Acute doxorubicin cardiotoxicity is associated with p53-induced inhibition of the mammalian target of rapamycin pathway

    National Research Council Canada - National Science Library

    Zhu, Wuqiang; Soonpaa, Mark H; Chen, Hanying; Shen, Weihua; Payne, R Mark; Liechty, Edward A; Caldwell, Randall L; Shou, Weinian; Field, Loren J

    2009-01-01

    .... The cardiotoxic effects of doxorubicin are cumulative, which limits its chemotherapeutic dose. Free radical generation and p53-dependent apoptosis are thought to contribute to doxorubicin-induced cardiotoxicity. Adult transgenic (MHC-CB7...

  13. Graphene Quantum Dots Downregulate Multiple Multidrug-Resistant Genes via Interacting with Their C-Rich Promoters.

    Science.gov (United States)

    Luo, Chao; Li, Yanfang; Guo, Lijuan; Zhang, Fangwei; Liu, Hui; Zhang, Jiali; Zheng, Jing; Zhang, Jingyan; Guo, Shouwu

    2017-11-01

    Multidrug resistance (MDR) is the major factor in the failure of many forms of chemotherapy, mostly due to the increased efflux of anticancer drugs that mediated by ATP-binding cassette (ABC) transporters. Therefore, inhibiting ABC transporters is one of effective methods of overcoming MDR. However, high enrichment of ABC transporters in cells and their broad substrate spectra made to circumvent MDR are almost insurmountable by a single specific ABC transporter inhibitor. Here, this study demonstrates that graphene quantum dots (GQDs) could downregulate the expressions of P-glycoprotein, multidrug resistance protein MRP1, and breast cancer resistance protein genes via interacting with C-rich regions of their promoters. This is the first example that a single reagent could suppress multiple MDR genes, suggesting that it will be possible to target multiple ABC transporters simultaneously with a single reagent. The inhibitory ability of the GQDs to these drug-resistant genes is validated further by reversing the doxorubicin resistance of MCF-7/ADR cells. Notably, GQDs have superb chemical and physical properties, unique structure, low toxicity, and high biocompatibility; hence, their capability of inhibiting multiple drug-resistant genes holds great potential in cancer therapy. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Reversible lysine-specific demethylase 1 antagonist HCI-2509 inhibits growth and decreases c-MYC in castration- and docetaxel-resistant prostate cancer cells.

    Science.gov (United States)

    Gupta, S; Weston, A; Bearrs, J; Thode, T; Neiss, A; Soldi, R; Sharma, S

    2016-12-01

    Lysine-specific demethylase 1 (LSD1 or KDM1A) overexpression correlates with poor survival and castration resistance in prostate cancer. LSD1 is a coregulator of ligand-independent androgen receptor signaling promoting c-MYC expression. We examined the antitumor efficacy of LSD1 inhibition with HCI-2509 in advanced stages of prostate cancer. Cell survival, colony formation, histone methylation, c-MYC level, c-MYC expression, cell cycle changes and in vivo efficacy were studied in castration-resistant prostate cancer cells upon treatment with HCI-2509. In vitro combination studies, using HCI-2509 and docetaxel, were performed to assess the synergy. Cell survival, colony formation, histone methylation and c-myc levels were studied in docetaxel-resistant prostate cancer cells treated with HCI-2509. HCI-2509 is cytotoxic and inhibits colony formation in castration-resistant prostate cancer cells. HCI-2509 treatment causes a dose-dependent increase in H3K9me2 (histone H3lysine 9) levels, a decrease in c-MYC protein, inhibition of c-MYC expression and accumulation in the G0/G1 phase of the cell cycle in these cells. PC3 xenografts in mice have a significant reduction in tumor burden upon treatment with HCI-2509 with no associated myelotoxicity or weight loss. More synergy is noted at sub-IC50 (half-maximal inhibitory concentration) doses of docetaxel and HCI-2509 in PC3 cells than in DU145 cells. HCI-2509 has growth-inhibitory efficacy and decreases the c-myc level in docetaxel-resistant prostate cancer cells. LSD1 inhibition with HCI-2509 decreases the c-MYC level in poorly differentiated prostate cancer cell lines and has a therapeutic potential in castration- and docetaxel-resistant prostate cancer.

  15. Nuclear uptake of ultrasmall gold-doxorubicin conjugates imaged by fluorescence lifetime imaging microscopy (FLIM) and electron microscopy.

    Science.gov (United States)

    Zhang, Xuan; Shastry, Sathvik; Bradforth, Stephen E; Nadeau, Jay L

    2015-01-07

    Fluorescence lifetime imaging microscopy (FLIM) has been used to image free and encapsulated doxorubicin (Dox) uptake into cells, since interaction of Dox with DNA leads to a characteristic lifetime change. However, none of the reported Dox conjugates were able to enter cell nuclei. In this work, we use FLIM to show nuclear uptake of 2.7 nm mean diameter Au nanoparticles conjugated to Dox. The pattern of labelling differed substantially from what was seen with free Dox, with slower nuclear entry and stronger cytoplasmic labelling at all time points. As the cells died, the pattern of labelling changed further as intracellular structures disintegrated, consistent with association of Au-Dox to membranes. The patterns of Au distribution and intracellular structure changes were confirmed using electron microscopy, and indicate different mechanisms of cytotoxicity with stable Au-Dox conjugates compared to Dox alone. Such conjugates are promising tools for overcoming resistance in Dox-resistant cancers.

  16. Piperine, a piperidine alkaloid from Piper nigrum re-sensitizes P-gp, MRP1 and BCRP dependent multidrug resistant cancer cells.

    Science.gov (United States)

    Li, Sen; Lei, Yu; Jia, Yingjie; Li, Na; Wink, Michael; Ma, Yonggang

    2011-12-15

    Over-expression of P-gp, MRP1 and BCRP in tumor cells is one of the important mechanisms leading to multidrug resistance (MDR), which impairs the efficacy of chemotherapy. P-gp, MRP1 and BCRP are ABC (ATP-Binding Cassette) transporters, which can expel a variety of lipophilic anti-cancer drugs and protect tumor cells. During a screening of MDR reversal agents among alkaloids of various structural types, a piperidine alkaloid, piperine (a main piperidine alkaloid in Piper nigurm) was identified as an inhibitor. Piperine can potentiate the cytotoxicity of anti-cancer drugs in resistant sublines, such as MCF-7/DOX and A-549/DDP, which were derived from MCF-7 and A-549 cell lines. At a concentration of 50 μM piperine could reverse the resistance to doxorubicin 32.16 and 14.14 folds, respectively. It also re-sensitized cells to mitoxantrone 6.98 folds. In addition, long-term treatment of cells by piperine inhibits transcription of the corresponding ABC transporter genes. These results suggest that piperine can reverse MDR by multiple mechanisms and it may be a promising lead compound for future studies. Copyright © 2011 Elsevier GmbH. All rights reserved.

  17. Emergence of therapy resistance in multiple myeloma in heterogeneous microenvironment

    Science.gov (United States)

    Wu, Amy; Zhang, Qiucen; Lambert, Guillaume; Khin, Zayar; Silva, Ariosto; Gatenby, Robert; Kim, Hyungsung; Pourmand, Nader; Austin, Robert; Sturm, James

    2014-03-01

    Cancer chemotherapy resistance is always a problem that is not clear considering spatial heterogeneity in the tumor microenvironment. We culture multiple myeloma in a gradient from 0 to 20 nM of doxorubicin (genotoxic drug) across 2 mm wide region in a microfluidic device which mimics the tumor microenvironment with a chemotherapy drug gradient and microhabitats. Resistance of the multiple myeloma cells to doxorubicin emerged within two weeks. For the resistant cells evolved from the devices, the doxorubicin concentration that inhibits 50% of the controlled population increased by 16-fold than the parental cells. Whole transcriptome sequencing revealed that 39% of newly acquired mutational hotspots (the genes with more than 3 non-synonymous point mutation) of the resistant cells are involved in apoptosis and DNA repair. On the other hand, 40% of the non-mutated genes that are abnormally regulated in the resistant cells, are involved in metabolism, biosynthesis, and biomolecular transport. Among them, metabolic drug efflux pumps and oxidative stress scavengers are up-regulated to reduce the cytotoxicity of doxorubicin and further result in the resistance. The roles of the spatial drug gradients and microhabitats in rapid emergence of cancer resistance will be discussed. The project described was supported by the National Science Foundation and the National Cancer Institute.

  18. Hypoxia-induced cytotoxic drug resistance in osteosarcoma is independent of HIF-1Alpha.

    Directory of Open Access Journals (Sweden)

    Jennifer Adamski

    Full Text Available Survival rates from childhood cancer have improved dramatically in the last 40 years, such that over 80% of children are now cured. However in certain subgroups, including metastatic osteosarcoma, survival has remained stubbornly poor, despite dose intensive multi-agent chemotherapy regimens, and new therapeutic approaches are needed. Hypoxia is common in adult solid tumours and is associated with treatment resistance and poorer outcome. Hypoxia induces chemotherapy resistance in paediatric tumours including neuroblastoma, rhabdomyosarcoma and Ewing's sarcoma, in vitro, and this drug resistance is dependent on the oxygen-regulated transcription factor hypoxia inducible factor-1 (HIF-1. In this study the effects of hypoxia on the response of the osteosarcoma cell lines 791T, HOS and U2OS to the clinically relevant cytotoxics cisplatin, doxorubicin and etoposide were evaluated. Significant hypoxia-induced resistance to all three agents was seen in all three cell lines and hypoxia significantly reduced drug-induced apoptosis. Hypoxia also attenuated drug-induced activation of p53 in the p53 wild-type U2OS osteosarcoma cells. Drug resistance was not induced by HIF-1α stabilisation in normoxia by cobalt chloride nor reversed by the suppression of HIF-1α in hypoxia by shRNAi, siRNA, dominant negative HIF or inhibition with the small molecule NSC-134754, strongly suggesting that hypoxia-induced drug resistance in osteosarcoma cells is independent of HIF-1α. Inhibition of the phosphoinositide 3-kinase (PI3K pathway using the inhibitor PI-103 did not reverse hypoxia-induced drug resistance, suggesting the hypoxic activation of Akt in osteosarcoma cells does not play a significant role in hypoxia-induced drug resistance. Targeting hypoxia is an exciting prospect to improve current anti-cancer therapy and combat drug resistance. Significant hypoxia-induced drug resistance in osteosarcoma cells highlights the potential importance of hypoxia as a target

  19. Marine Natural Products as Breast Cancer Resistance Protein Inhibitors

    OpenAIRE

    Lilia Cherigo; Dioxelis Lopez; Sergio Martinez-Luis

    2015-01-01

    Breast cancer resistance protein (BCRP) is a protein belonging to the ATP-binding cassette (ABC) transporter superfamily that has clinical relevance due to its multi-drug resistance properties in cancer. BCRP can be associated with clinical cancer drug resistance, in particular acute myelogenous or acute lymphocytic leukemias. The overexpression of BCRP contributes to the resistance of several chemotherapeutic drugs, such as topotecan, methotrexate, mitoxantrone, doxorubicin and daunorubicin...

  20. Commonly Transmitted HIV-1 Drug Resistance Mutations in Reverse-Transcriptase and Protease in Antiretroviral Treatment-Naive Patients and Response to Regimens Containing Tenofovir Disoproxil Fumarate or Tenofovir Alafenamide.

    Science.gov (United States)

    Margot, Nicolas A; Wong, Pamela; Kulkarni, Rima; White, Kirsten; Porter, Danielle; Abram, Michael E; Callebaut, Christian; Miller, Michael D

    2017-03-15

    The presence of transmitted drug resistance mutations (TDRMs) in antiretroviral treatment (ART)-naive patients can adversely affect the outcome of ART. Resistance testing was conducted in 6704 ART-naive subjects predominantly from the United States and Europe in 9 clinical studies conducted by Gilead Sciences from 2000 to 2013. The presence of TDRMs increased during this period (from 5.2% to 11.4%), primarily driven by an increase in nonnucleoside reverse-transcriptase (RT) inhibitor (NNRTI) resistance mutations (from 0.3% to 7.1%), particularly K103N/S (increase from 0.3% to 5.3%). Nucleoside/nucleotide RT inhibitor mutations were found in 3.1% of patients. Only 1 patient had K65R (0.01%) and 7 had M184V/I (0.1%), despite high use of tenofovir disoproxil fumarate (TDF), emtricitabine, and lamivudine and potential transmission of resistance to these drugs. At least 1 thymidine-analogue mutations was present in 2.7% of patients with 0.07% harboring T215Y/F and 2.7% harboring T215 revertant mutations (T215rev). Patients with the combination of M41L + L210W + T215rev showed full human immunodeficiency virus RNA suppression while receiving a TDF- or tenofovir alafenamide-containing regimen. There was an overall increase of TDRMs among patients enrolling in clinical trials from 2000 through 2013, driven primarily by an increase in NNRTI resistance. However, the presence of common TDRMs, including thymidine-analogue mutations/T215rev, showed no impact on response to TDF- or tenofovir alafenamide-containing regimens.

  1. Sunflower oil supplementation has proinflammatory effects and does not reverse insulin resistance in obesity induced by high-fat diet in C57BL/6 mice.

    Science.gov (United States)

    Masi, Laureane Nunes; Martins, Amanda Roque; Rosa Neto, José César; do Amaral, Cátia Lira; Crisma, Amanda Rabello; Vinolo, Marco Aurélio Ramirez; de Lima Júnior, Edson Alves; Hirabara, Sandro Massao; Curi, Rui

    2012-01-01

    High consumption of polyunsaturated fatty acids, such as sunflower oil has been associated to beneficial effects in plasma lipid profile, but its role on inflammation and insulin resistance is not fully elucidated yet. We evaluated the effect of sunflower oil supplementation on inflammatory state and insulin resistance condition in HFD-induced obese mice. C57BL/6 male mice (8 weeks) were divided in four groups: (a) control diet (CD), (b) HFD, (c) CD supplemented with n-6 (CD + n-6), and (d) HFD supplemented with n-6 (HFD + n-6). CD + n-6 and HFD + n-6 were supplemented with sunflower oil by oral gavage at 2 g/Kg of body weight, three times per week. CD and HFD were supplemented with water instead at the same dose. HFD induced whole and muscle-specific insulin resistance associated with increased inflammatory markers in insulin-sensitive tissues and macrophage cells. Sunflower oil supplementation was not efficient in preventing or reducing these parameters. In addition, the supplementation increased pro-inflammatory cytokine production by macrophages and tissues. Lipid profile, on the other hand, was improved with the sunflower oil supplementation in animals fed HFD. In conclusion, sunflower oil supplementation improves lipid profile, but it does not prevent or attenuate insulin resistance and inflammation induced by HFD in C57BL/6 mice.

  2. Development and evaluation of an assay for HIV-1 protease and reverse transcriptase drug resistance genotyping of all major group-M subtypes

    NARCIS (Netherlands)

    Aitken, S.C.; Kliphuis, A.; Wallis, C.L.; Chu, M.L.; Fillekes, Q.; Barth, R.; Stevens, W.B.; Rinke de Wit, T.F.; Schuurman, R.

    2012-01-01

    BACKGROUND: High cost and varying sensitivity for non-B HIV-1 subtypes limits application of current commercial kits for HIV-1 drug resistance genotyping of all major HIV-1 group-M subtypes. OBJECTIVES: Our research aimed to develop and validate an assay specific for all major HIV-1 group-M subtypes

  3. Reversal of typical multidrug resistance by cyclosporin and its non-immunosuppressive analogue SDZ PSC 833 in Chinese hamster ovary cells expressing the mdr1 phenotype

    NARCIS (Netherlands)

    P.A.W. te Boekhorst (Peter); J. van Kapel (Jan); M. Schoester (Martijn); P. Sonneveld (Pieter)

    1992-01-01

    markdownabstractSummary The new non-immunosuppressive cyclosporin derivative SDZ PSC 833 (PSC) is a potent agent used to overcome typical multidrug resistance (MDR) associated with overexpression of themdr1 gene encoding for a P-170 glycoprotein. In the present study, the efficacy of PSC as

  4. Modulatory effects of meloxicam on cardiotoxicity and antitumor activity of doxorubicin in mice.

    Science.gov (United States)

    Hassan, Memy H; El-Beshbishy, Hesham A; Aly, Hamdy; Attia, Sabry M; Bahashwan, Saleh A; Ghobara, Mohamed M

    2014-09-01

    This study was undertaken to assess the possible modulatory effects and mechanisms of meloxicam, a cyclooxygenase-2 inhibitor, on the antitumor activity and cardiotoxicity of doxorubicin in a mice model of mammary carcinoma. Solid tumor mass was developed in female albino mice using Ehrlich carcinoma cells. Forty mice-bearing tumor were divided randomly into four groups for treatment: with saline, meloxicam 10 mg/kg, doxorubicin 5 mg/kg and meloxicam 1 h ahead of doxorubicin, twice weekly for 2 weeks. Tumor volume was followed up and cardiac protective utility was estimated via measuring heart and serum parameters. Meloxicam expressed a non-significant increase in doxorubicin antitumor activity. Conversely, meloxicam significantly (p Meloxicam significantly abrogated doxorubicin-induced disturbance in heart histology and relative heart weight to body weight. Meloxicam normalized doxorubicin-induced suppression in heart antioxidant enzymes activities and gene expressions [superoxide dismutase, glutathione peroxidase (GSH-Px) and catalase], and heart GSH content. In addition, meloxicam ameliorated doxorubicin-induced disturbance in phase II metabolizing enzyme, cardiac quinone reductase (QR), at activity level and mRNA expression. Meloxicam protects heart against doxorubicin toxicity without affecting its antitumor activity against solid mammary cancer model in mice. This protective effect is attributed to antioxidant effect, antiradical effect, antiinflammatory action, antiapoptotic effect and induction of QR enzyme.

  5. Molecularly imprinted fluorescent probe based on FRET for selective and sensitive detection of doxorubicin

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Zhifeng, E-mail: 897061147@qq.com [College of Chemistry and Materials Science, Hengyang Normal University, Key Laboratory of Functional Organometallic Materials of Hunan Province University, Hengyang 421008 (China); Deng, Peihong; Li, Junhua [College of Chemistry and Materials Science, Hengyang Normal University, Key Laboratory of Functional Organometallic Materials of Hunan Province University, Hengyang 421008 (China); Xu, Li [Department of Applied Chemistry, College of Materials and Energy, South China Agricultural University, Guangzhou 510642 (China); Tang, Siping [College of Chemistry and Materials Science, Hengyang Normal University, Key Laboratory of Functional Organometallic Materials of Hunan Province University, Hengyang 421008 (China)

    2017-04-15

    Highlights: • FRET-based molecularly imprinted probe for detection of doxorubicin was prepared. • The detection limit of the probe was 13.8 nM for doxorubicin. • The FRET-based probe had a higher selectivity for the template than ordinary MIMs. - Abstract: In this work, a new type of fluorescent probe for detection of doxorubicin has been constructed by the combined use of fluorescence resonance energy transfer (FRET) technology and molecular imprinting technique (MIT). Using doxorubicin as the template, the molecularly imprinted polymer thin layer was fabricated on the surfaces of carbon dot (CD) modified silica by sol-gel polymerization. The excitation energy of the fluorescent donor (CDs) could be transferred to the fluorescent acceptor (doxorubicin). The FRET based fluorescent probe demonstrated high sensitivity and selectivity for doxorubicin. The detection limit was 13.8 nM. The fluorescent probe was successfully applied for detecting doxorubicin in doxorubicin-spiked plasmas with a recovery of 96.8–103.8%, a relative standard deviation (RSD) of 1.3–2.8%. The strategy for construction of FRET-based molecularly imprinted materials developed in this work is very promising for analytical applications.

  6. Polyelectrolyte-Mediated Transport of Doxorubicin Through the Bilayer Lipid Membrane

    Science.gov (United States)

    Yaroslavov, Alexander A.; Kitaeva, Marina V.; Melik-Nubarov, Nikolay S.; Menger, Frederic M.

    A model is developed for the effect of ionic polymers on the transport of doxorubicin, an antitumor drug, through a bilayer membrane. Accordingly, a protonated (cationic) form of doxorubicin binds to an anionic polymer, poly(acrylic acid), the resulting complex being several hundred nanometers in size. Nevertheless, large complex species associate with neutral egg lecithin liposomes by means of hydrophobic attraction between the doxorubicin and the liposome bilayer. Then, the doxorubicin enters the liposome interior which has been imparted with an acidic buffer to protonate the doxorubicin. The rate of transmembrane Dox permeation decreases when elevating the polyacid-to-doxorubicin ratio. A cationic polymer, polylysine, being coupled with liposomes containing the negative lipid cardiolipin, accelerates membrane transport of doxorubicin with the maximum rate at a complete neutralization of the membrane charge by an interacting polycation. The effect of a polycation on doxorubicin transport becomes more pronounced as small negative liposomes (60-80 nm in diameter) are changed to larger ones (approx. 600 nm in diameter). An opportunity thus opens up for the manipulation of the kinetics of drug uptake by cells and, ultimately, the control of the pharmaceutical action of drugs.

  7. TRIB3 downregulation enhances doxorubicin-induced cytotoxicity in gastric cancer cells.

    Science.gov (United States)

    Wu, I-Jung; Lin, Rong-Jaan; Wang, Hsin-Chiao; Yuan, Tein-Ming; Chuang, Show-Mei

    2017-05-15

    TRIB3, which is a pseudokinase known to regulate multiple pro-survival pathways, appears to be a potential therapeutic target for the treatment of human tumors. However, its precise role in cancer is controversial, as TRIB3 protein levels have been associated with both good and poor prognosis in cancer patients. Here, we investigated the significance of TRIB3 expression in the survival of gastric cancer cells exposed to anticancer drugs. We found that the tested anticancer drug, doxorubicin, induced cytotoxicity by decreasing TRIB3 transcription, which was followed by apoptotic cell death. Moreover, TRIB3 siRNA knockdown appeared to enhance doxorubicin-induced apoptosis in gastric cancer cells, concurrently with altering the expression of downstream apoptotic factors. Conversely, overexpression of TRIB3 significantly protected cells against doxorubicin-induced apoptosis. Our results indicate that downregulation of TRIB3 appears to promote cell death and enhance doxorubicin-induced apoptosis, supporting the anti-apoptotic role of TRIB3. The inductions of three classes of MAPKs failed to affect doxorubicin-mediated TRIB3 downregulation, while TRIB3 overexpression did not affect doxorubicin-induced MAPK activation. In sum, our findings indicate that TRIB3 plays an anti-apoptotic role in doxorubicin-treated gastric cancer cell lines, perhaps indicating that the status of TRIB3 expression in response to anticancer drugs, such as doxorubicin, irinotecan or oxaliplatin, may reflect the efficiency for cancer therapy. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Reversible Statistics

    DEFF Research Database (Denmark)

    Tryggestad, Kjell

    2004-01-01

    The study aims is to describe how the inclusion and exclusion of materials and calculative devices construct the boundaries and distinctions between statistical facts and artifacts in economics. My methodological approach is inspired by John Graunt's (1667) Political arithmetic and more recent work...... within constructivism and the field of Science and Technology Studies (STS). The result of this approach is here termed reversible statistics, reconstructing the findings of a statistical study within economics in three different ways. It is argued that all three accounts are quite normal, albeit...... in different ways. The presence and absence of diverse materials, both natural and political, is what distinguishes them from each other. Arguments are presented for a more symmetric relation between the scientific statistical text and the reader. I will argue that a more symmetric relation can be achieved...

  9. Analysis of miRNA expression profile induced by short term starvation in breast cancer cells treated with doxorubicin

    Science.gov (United States)

    Fanale, Daniele; Buscemi, Silvio; Ciaccio, Marcello; Russo, Antonio; Castorina, Sergio; Bazan, Viviana

    2017-01-01

    Recent studies showed that dietary approaches restricting food intake can be helpful to hinder tumor progression. To date, the molecular mechanisms are unclear and a key role seems to be exerted by nutrient-related signaling pathways. Since several evidences showed that non-coding small RNAs, including microRNAs, are correlated to cancer progression and antiblastic treatment response, our work aims to study their involvement in a triple negative breast cancer (TNBC) cell line treated with doxorubicin under Short Term Starvation (STS) condition. Human TNBC cell line MDA-MB-231 and healthy breast cell line MCF10A were treated with 1 μM doxorubicin for 24 h under STS condition for 48 h and miRNA expression profiles were analyzed using Taqman® Low Density Array A human microRNA microfluidic cards. In addition, the expression of specific mRNAs and miRNAs differentially expressed under STS was analyzed using Real-time PCR analyses. MiRNA expression profile analysis in MDA-MB-231 and MCF10A cells treated with doxorubicin under STS for 48 h could explain the molecular mechanisms underlying anticancer effects associated to STS. Among deregulated miRNAs, a subset, including miR-15b, miR-23a, miR-26a, miR-29a, miR-106b, miR-128, miR-149, miR-181a, miR-192, miR-193b, miR-195, miR-324-3p and miR-494, has been shown to be involved in pathways related to drug sensitivity/resistance. The obtained data from our study suggest a potential involvement of some miRNAs in molecular pathways mediating the anticancer effects of STS in doxorubicin-treated breast cancer cells. Preliminary results seem to be encouraging and, in future, could allow the discovery of new potential targets useful for the development of new therapeutic approaches. PMID:29069757

  10. 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.

  11. Effect of Coenzyme-Q10 on Doxorubicin-Induced Nephrotoxicity in Rats

    Directory of Open Access Journals (Sweden)

    Azza A. K. El-Sheikh

    2012-01-01

    Full Text Available Nephrotoxicity is one of the limiting factors for using doxorubicin (Dox as an anticancer chemotherapeutic. Here, we investigated possible protective effect of coenzyme-Q10 (CoQ10 on Dox-induced nephrotoxicity and the mechanisms involved. Two doses (10 and 100 mg/kg of CoQ10 were administered orally to rats for 8 days, in the presence or absence of nephrotoxicity induced by a single intraperitoneal injection of Dox (15 mg/kg at day 4 of the experiment. Our results showed that the low dose of CoQ10 succeeded in reversing Dox-induced nephrotoxicity to control levels (e.g., levels of blood urea nitrogen and serum creatinine, concentrations of renal reduced glutathione (GSH and malondialdehyde, catalase activity and caspase 3 expression, and renal histopathology. Alternatively, the high dose of CoQ10 showed no superior nephroprotection over the low dose, as there were no significant improvements in renal histopathology, catalase activity, or caspase 3 expression compared to the Dox-treated group. Interestingly, the high dose of CoQ10 alone significantly decreased renal GSH level as well as catalase activity and caused a mild induction of caspase 3 expression compared to control, probably due to a prooxidant effect at this dose of CoQ10. We conclude that CoQ10 protects from Dox-induced nephrotoxicity with a precaution to dosage adjustment.

  12. A hyaluronic acid nanogel for photo-chemo theranostics of lung cancer with simultaneous light-responsive controlled release of doxorubicin

    Science.gov (United States)

    Khatun, Zehedina; Nurunnabi, Md; Nafiujjaman, Md; Reeck, Gerald R.; Khan, Haseeb A.; Cho, Kwang Jae; Lee, Yong-Kyu

    2015-06-01

    The combined delivery of photo- and chemo-therapeutic agents is an emerging strategy to overcome drug resistance in treating cancer, and controlled light-responsive drug release is a proven tactic to produce a continuous therapeutic effect for a prolonged duration. Here, a combination of light-responsive graphene, chemo-agent doxorubicin and pH-sensitive disulfide-bond linked hyaluronic acid form a nanogel (called a graphene-doxorubicin conjugate in a hyaluronic acid nanogel) that exerts an activity with multiple effects: thermo and chemotherapeutic, real-time noninvasive imaging, and light-glutathione-responsive controlled drug release. The nanogel is mono-dispersed with an average diameter of 120 nm as observed by using TEM and a hydrodynamic size analyzer. It has excellent photo-luminescence properties and good stability in buffer and serum solutions. Graphene itself, being photoluminescent, can be considered an optical imaging contrast agent as well as a heat source when excited by laser irradiation. Thus the nanogel shows simultaneous thermo-chemotherapeutic effects on noninvasive optical imaging. We have also found that irradiation enhances the release of doxorubicin in a controlled manner. This release synergizes therapeutic activity of the nanogel in killing tumor cells. Our findings demonstrate that the graphene-doxorubicin conjugate in the hyaluronic acid nanogel is very effective in killing the human lung cancer cell line (A549) with limited toxicity in the non-cancerous cell line (MDCK).The combined delivery of photo- and chemo-therapeutic agents is an emerging strategy to overcome drug resistance in treating cancer, and controlled light-responsive drug release is a proven tactic to produce a continuous therapeutic effect for a prolonged duration. Here, a combination of light-responsive graphene, chemo-agent doxorubicin and pH-sensitive disulfide-bond linked hyaluronic acid form a nanogel (called a graphene-doxorubicin conjugate in a hyaluronic acid

  13. Milk diets influence doxorubicin-induced intestinal toxicity in piglets

    DEFF Research Database (Denmark)

    Shen, R. L.; Pontoppidan, P. E.; Rathe, M.

    2016-01-01

    with doxorubicin (DOX) treatment. Five-day-old pigs were administered DOX (1 × 100 mg/m(2)) or an equivalent volume of saline (SAL) and either fed formula (DOX-Form, n = 9, or SAL-Form, n = 7) or bovine colostrum (DOX-Colos, n = 9, or SAL-Colos, n = 7). Pigs were euthanized 5 days after initiation of chemotherapy...... IL-8 levels compared with DOX-Form (all P single dose of DOX induces intestinal toxicity in preweaned pigs...

  14. Reverse transcriptase and protease inhibitor resistant mutations in art treatment naïve and treated HIV-1 infected children in India A Short Review

    Directory of Open Access Journals (Sweden)

    Dinesh Bure,

    2016-08-01

    Full Text Available Introduction of first line and second line antiretroviral therapy has dramatically improved the quality of life and survival of the HIV-1 infected individuals. Extension of this therapy in children has similar effect. However the emergence of drug selected resistance has hampered the response to the therapy. A database of prevalence of drug resistance mutations in the Indian children both ART naïve and treated will help in deciding the appropriate regimen for the individual patient as well as formulating the policies regarding the composition of drugs included in the fixed dose combinations