WorldWideScience

Sample records for reverses doxorubicin resistance

  1. Endoplasmic reticulum stress-induced resistance to doxorubicin is reversed by paeonol treatment in human hepatocellular carcinoma cells.

    Directory of Open Access Journals (Sweden)

    Lulu Fan

    Full Text Available BACKGROUND: Endoplasmic reticulum stress (ER stress is generally activated in solid tumors and results in tumor cell anti-apoptosis and drug resistance. Paeonol (Pae, 2-hydroxy-4-methoxyacetophenone, is a natural product extracted from the root of Paeonia Suffruticosa Andrew. Although Pae displays anti-neoplastic activity and increases the efficacy of chemotherapeutic drugs in various cell lines and in animal models, studies related to the effect of Pae on ER stress-induced resistance to chemotherapeutic agents in hepatocellular carcinoma (HCC are poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we investigated the effect of the endoplasmic reticulum (ER stress response during resistance of human hepatocellular carcinoma cells to doxorubicin. Treatment with the ER stress-inducer tunicamycin (TM before the addition of doxorubicin reduced the rate of apoptosis induced by doxorubicin. Interestingly, co-pretreatment with tunicamycin and Pae significantly increased apoptosis induced by doxorubicin. Furthermore, induction of ER stress resulted in increasing expression of COX-2 concomitant with inactivation of Akt and up-regulation of the pro-apoptotic transcription factor CHOP (GADD153 in HepG2 cells. These cellular changes in gene expression and Akt activation may be an important resistance mechanism against doxorubicin in hepatocellular carcinoma cells undergoing ER stress. However, co-pretreatment with tunicamycin and Pae decreased the expression of COX-2 and levels of activation of Akt as well as increasing the levels of CHOP in HCC cells. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that Pae reverses ER stress-induced resistance to doxorubicin in human hepatocellular carcinoma cells by targeting COX-2 mediated inactivation of PI3K/AKT/CHOP.

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

    International Nuclear Information System (INIS)

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

    1998-01-01

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

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

    Science.gov (United States)

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

    Science.gov (United States)

    Dash, Tapan K; Konkimalla, V Badireenath

    2017-02-01

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

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

    Science.gov (United States)

    Angelini, A; Ciofani, G; Conti, P

    2015-01-01

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

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

    Science.gov (United States)

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

    2001-10-01

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

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

    Science.gov (United States)

    Xiong, Sang; Xiao, Gong-Wei

    2018-04-01

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

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  9. Doxorubicin loaded Polymeric Nanoparticulate Delivery System to overcome drug resistance in osteosarcoma

    International Nuclear Information System (INIS)

    Susa, Michiro; Iyer, Arun K; Ryu, Keinosuke; Hornicek, Francis J; Mankin, Henry; Amiji, Mansoor M; Duan, Zhenfeng

    2009-01-01

    Drug resistance is a primary hindrance for the efficiency of chemotherapy against osteosarcoma. Although chemotherapy has improved the prognosis of osteosarcoma patients dramatically after introduction of neo-adjuvant therapy in the early 1980's, the outcome has since reached plateau at approximately 70% for 5 year survival. The remaining 30% of the patients eventually develop resistance to multiple types of chemotherapy. In order to overcome both the dose-limiting side effects of conventional chemotherapeutic agents and the therapeutic failure incurred from multidrug resistant (MDR) tumor cells, we explored the possibility of loading doxorubicin onto biocompatible, lipid-modified dextran-based polymeric nanoparticles and evaluated the efficacy. Doxorubicin was loaded onto a lipid-modified dextran based polymeric nano-system. The effect of various concentrations of doxorubicin alone or nanoparticle loaded doxorubicin on KHOS, KHOS R2 , U-2OS, and U-2OS R2 cells was analyzed. Effects on drug retention, immunofluorescence, Pgp expression, and induction of apoptosis were also analyzed. Dextran nanoparticles loaded with doxorubicin had a curative effect on multidrug resistant osteosarcoma cell lines by increasing the amount of drug accumulation in the nucleus via Pgp independent pathway. Nanoparticles loaded with doxorubicin also showed increased apoptosis in osteosarcoma cells as compared with doxorubicin alone. Lipid-modified dextran nanoparticles loaded with doxorubicin showed pronounced anti-proliferative effects against osteosarcoma cell lines. These findings may lead to new treatment options for MDR osteosarcoma

  10. Posterior reversible leukoencephalopathy syndrome secondary to hepatic transarterial chemoembolization with doxorubicin drug eluting beads

    Science.gov (United States)

    Kistler, C. Andrew; McCall, Joseph Caleb; Ghumman, Saad Sultan; Ali, Ijlal Akbar

    2014-01-01

    Posterior reversible encephalopathy syndrome (PRES) is a rare complication of transarterial chemoembolization (TACE) used to treat liver metastases and has never been reported in a patient with metastatic uveal melanoma (UM) to the liver. We report the first case of PRES secondary to TACE with drug eluting beads (DEBs) loaded with doxorubicin in a 56-year-old woman with metastatic UM to the liver. PMID:24772346

  11. A Novel Submicron Emulsion System Loaded with Doxorubicin Overcome Multi-Drug Resistance in MCF-7/ADR Cells.

    Science.gov (United States)

    Zhou, W P; Hua, H Y; Sun, P C; Zhao, Y X

    2015-01-01

    The purpose of the present study was to develop the Solutol HS15-based doxorubicin submicron emulsion with good stability and overcoming multi-drug resistance. In this study, we prepared doxorubicin submicron emulsion, and examined the stability after autoclaving, the in vitro cytotoxic activity, the intracellular accumulation and apoptpsis of doxorubicin submicron emulsion in MCF-7/ADR cells. The physicochemical properties of doxorubicin submicron emulsion were not significantly affected after autoclaving. The doxorubicin submicron emulsion significantly increased the intracellular accumulation of doxorubicin submicron emulsion and enhanced cytotoxic activity and apoptotic effects of doxorubicin. These results may be correlated to doxorubicin submicron emulsion inhibitory effects on efflux pumps through the progressive release of intracellular free Solutol HS15 from doxorubicin submicron emulsion. Furthermore, these in vitro results suggest that the Solutol HS15-based submicron emulsion may be a potentially useful drug delivery system to circumvent multi-drug resistance of tumor cells.

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

    Science.gov (United States)

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

    2016-05-31

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

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

    Directory of Open Access Journals (Sweden)

    Zoey Tay

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

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

    International Nuclear Information System (INIS)

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

    1984-01-01

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

  15. Green Tea Catechin-Based Complex Micelles Combined with Doxorubicin to Overcome Cardiotoxicity and Multidrug Resistance

    Science.gov (United States)

    Cheng, Tangjian; Liu, Jinjian; Ren, Jie; Huang, Fan; Ou, Hanlin; Ding, Yuxun; Zhang, Yumin; Ma, Rujiang; An, Yingli; Liu, Jianfeng; Shi, Linqi

    2016-01-01

    Chemotherapy for cancer treatment has been demonstrated to cause some side effects on healthy tissues and multidrug resistance of the tumor cells, which greatly limits therapeutic efficacy. To address these limitations and achieve better therapeutic efficacy, combination therapy based on nanoparticle platforms provides a promising approach through delivering different agents simultaneously to the same destination with synergistic effect. In this study, a novel green tea catechin-based polyion complex (PIC) micelle loaded with doxorubicin (DOX) and (-)-Epigallocatechin-3-O-gallate (EGCG) was constructed through electrostatic interaction and phenylboronic acid-catechol interaction between poly(ethylene glycol)-block-poly(lysine-co-lysine-phenylboronic acid) (PEG-PLys/PBA) and EGCG. DOX was co-loaded in the PIC micelles through π-π stacking interaction with EGCG. The phenylboronic acid-catechol interaction endowed the PIC micelles with high stability under physiological condition. Moreover, acid cleavability of phenylboronic acid-catechol interaction in the micelle core has significant benefits for delivering EGCG and DOX to same destination with synergistic effects. In addition, benefiting from the oxygen free radicals scavenging activity of EGCG, combination therapy with EGCG and DOX in the micelle core could protect the cardiomyocytes from DOX-mediated cardiotoxicity according to the histopathologic analysis of hearts. Attributed to modulation of EGCG on P-glycoprotein (P-gp) activity, this kind of PIC micelles could effectively reverse multidrug resistance of cancer cells. These results suggested that EGCG based PIC micelles could effectively overcome DOX induced cardiotoxicity and multidrug resistance. PMID:27375779

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

    Science.gov (United States)

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

    2017-02-01

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

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

    Science.gov (United States)

    Roncuzzi, Laura; Pancotti, Fabia; Baldini, Nicola

    2014-07-01

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

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

    Directory of Open Access Journals (Sweden)

    Timothy B Lautz

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

  19. Hypoxia-induced resistance to doxorubicin and methotrexate in human melanoma cell lines in vitro.

    Science.gov (United States)

    Sanna, K; Rofstad, E K

    1994-07-15

    Rodent cell lines can develop resistance to doxorubicin and methotrexate during hypoxic stress. This has so far not been observed in human tumor cell lines. The purpose of our communication is to show that doxorubicin and methotrexate resistance can also develop in human melanoma cells during exposure to hypoxia. Four cell lines (BEX-c, COX-c, SAX-c, WIX-c) have been studied. Cells were exposed to hypoxia (O2 concentration WIX-c. BEX-c and SAX-c were sensitive to methotrexate without hypoxia pre-treatment, whereas COX-c and WIX-c were resistant initially. Hypoxia-induced drug resistance was present immediately after reoxygenation and tended to decrease with time but remained statistically significant even 42 hr after reoxygenation.

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

    Science.gov (United States)

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

    2013-12-01

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

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

    Directory of Open Access Journals (Sweden)

    Katarzyna Zabielska-Koczywąs

    2018-02-01

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

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

    Science.gov (United States)

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

    2017-11-28

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

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    Jingpei Long

    2015-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

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

    2015-03-01

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

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

    Science.gov (United States)

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

    1986-08-01

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

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

    Science.gov (United States)

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

    2012-07-01

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

  9. Partial circumvention of P-glycoprotein-mediated multidrug resistance by doxorubicin-14-O-hemiadipate.

    Science.gov (United States)

    Leontieva, Olga V; Preobrazhenskaya, Maria N; Bernacki, Ralph J

    2002-02-01

    Previously, we have reported partial circumvention of P-glycoprotein (Pgp)-associated resistance to doxorubicin (Dox) in MCF7/R human breast carcinoma and P388/R murine leukemia cell lines by doxorubicin-14-O-hemiadipate (H-Dox) [Povarov L.S. et al. (1995) Russian J. Bioorganic Chemistry 21: 797-803]. We felt that these changes were due to alterations in the cellular pharmacokinetics of the analog in multidrug (MDR) resistant cells, as compared to that of Dox. To address this hypothesis, we performed comparative studies of the accumulation, retention and intracellular localization of H-Dox and Dox in Dox-sensitive murine leukemia cell line P388/S and its Dox-selected. Pgp-positive drug resistant P388/R subline. These studies were performed in the presence or absence of cyclosporin A (CsA), a competitive inhibitor of Pgp. Flow cytometric analysis revealed significant differences in Dox and H-Dox accumulation in P388/R cells when compared to P388/S cells. In P388/R versus P388/S cells, there was a 38-fold decrease in Dox accumulation, but only a 5-fold decrease in H-Dox accumulation, indicating over a 7-fold increase in H-Dox buildup in resistant cells. CsA did not affect uptake or retention of either drug by sensitive cells. However, coincubation with CsA resulted in a 54-fold increase in Dox accumulation and only a 5-fold increase in H-Dox uptake in P388/R cells, restoring anthracycline levels in P388/R to 100% of that found in P388/S cells. Once internalized by the resistant cells, H-Dox was retained better than Dox regardless of presence or absence of CsA. Confocal microscopic analysis revealed the presence of H-Dox but no Dox in cellular nuclei of P388/R cells. Thus, increased activity of H-Dox toward P388/R cells was correlated with its enhanced ability to enter and be retained in these cells, and also with redistribution of H-Dox into the nuclei of the resistant cells as compared to Dox. Overall, our findings support our initial hypothesis and provide evidence

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

    International Nuclear Information System (INIS)

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

    2011-01-01

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

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

    Science.gov (United States)

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

    2017-07-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-01-10

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

  13. 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.

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

  15. Solutol HS 15, nontoxic polyoxyethylene esters of 12-hydroxystearic acid, reverses multidrug resistance.

    Science.gov (United States)

    Coon, J S; Knudson, W; Clodfelter, K; Lu, B; Weinstein, R S

    1991-02-01

    A recently developed non-ionic surfactant called Solutol HS 15 (poly-oxyethylene esters of 12-hydroxystearic acid), with low toxicity in vivo, was shown to reverse completely the multidrug resistance of KB 8-5 and KB 8-5-11 human epidermoid carcinoma cells in vitro but did not potentiate drug toxicity in drug-sensitive KB 3-1 cells. At a concentration of 10% of its own IC50 (mean concentration of drug that causes 50% inhibition of cell growth compared to controls), Solutol HS 15 produced a 35-, 28-, and 42-fold reduction in the resistance of KB 8-5-11 cells to colchicine, vinblastine, and doxorubicin, respectively. Solutol HS 15 was relatively much more potent than the prototypic reversing agent, verapamil, for reversing colchicine resistance, compared to the ability of each agent to reverse colchicine resistance, compared to the ability of each agent to reverse vinblastine resistance. Like verapamil, Solutol HS 15 promoted a 50-fold accumulation of rhodamine 123 in KB 8-5-11 cells, as measured by flow cytometry. Also, Solutol HS 15 and verapamil reduced the efflux of rhodamine 123 from KB 8-5-11 cells previously loaded with rhodamine 123 to a similar low rate. Solutol HS 15 did not affect the transport of alanine or glucose into KB 8-5-11 cells, indicating that its effect upon membrane active transport is not entirely nonspecific. Considering their different structure and different relative potency for reversing colchicine resistance, Solutol HS 15 and verapamil probably reverse multidrug resistance by different mechanisms. Solutol HS 15 merits consideration as a potential therapeutic agent because of its effectiveness for reversing multidrug resistance in vitro and its low toxicity in vivo.

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

    Directory of Open Access Journals (Sweden)

    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.

  17. Novel nanostructured enoxaparin sodium-PLGA hybrid carriers overcome tumor multidrug resistance of doxorubicin hydrochloride.

    Science.gov (United States)

    Wang, Jia; Wu, Lei; Kou, Longfa; Xu, Meng; Sun, Jin; Wang, Yongjun; Fu, Qiang; Zhang, Peng; He, Zhonggui

    2016-11-20

    Novel enoxaparin sodium-PLGA hybrid nanocarries (EPNs) were successfully designed for sustained delivery of hydrophilic cationic doxorubicin hydrochloride (DOX) and to overcome multidrug resistance (MDR). By incorporation of the negative polymer of enoxaparin sodium (ES), DOX was highly encapsulated into EPNs with an encapsulation efficiency of 92.49%, and ES effectively inhibited the proliferation of HUVEC cell lines. The in vivo pharmacokinetics study after intravenous injection indicated that DOX-loaded EPNs (DOX-EPNs) exhibited a higher area under the curve (AUC) and a longer half-life (t 1/2 ) in comparison with DOX solution (DOX-Sol). The biodistribution study demonstrated that DOX-EPNs increased the DOX level in plasma and decreased the accumulation of DOX in liver and spleen. Compared with DOX-Sol, DOX-EPNs increased the cytotoxicity in P-gp over-expressing MCF-7/Adr cells, attributed to the higher intracellular efficiency of DOX produced by the EPNs. DOX-EPNs entered into resistant tumor cells by multiple endocytosis pathways, which resulted in overcoming the multidrug resistance of MCF-7/Adr cells by escaping the efflux induced by P-gp transporters. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Enhanced anticancer activity and circumvention of resistance mechanisms by novel polymeric/ phospholipidic nanocarriers of doxorubicin.

    Science.gov (United States)

    Senkiv, Y; Riabtseva, A; Heffeter, P; Boiko, N; Kowol, C R; Jungwith, U; Shlyakhtina, Y; Garasevych, S G; Mitina, N; Berger, W; Zaichenko, A; Stoika, R

    2014-07-01

    Severe toxic side effects and drug resistance are the major limitations of doxorubicin (Dox), one of the most potent anticancer agents in clinical use. Nanocarrier preparations offer the opportunity to overcome these drawbacks, which is reflected in the clinical approval of two liposomal Dox preparations. Additionally, there are many attempts to enhance the activity of Dox against multi-drug resistant (MDR) cancer cells. However, most of these strategies resulted in the increased uptake of Dox in resistant cells, only, while it remained unchanged in chemo-sensitive cells. Here, we present a new polymeric-phospholipidic hybrid delivery system which distinctly enhanced the accumulation and activity of Dox in all tested cancer cell lines including several MDR cell models. Notably, the resistance levels against Dox were reduced from about 6-fold to about 2-fold. Moreover, the new nanocarriers were shown to rapidly (within 10 min) and effectively transport Dox into resistant as well as sensitive cancer cells. Consequently, treatment with the new Dox-containing nanocarriers resulted in effective cell cycle arrest in G2/M phase and ROS-induced cell death induction. Finally, the new nanocarriers were tested against NK/Ly lymphoma and L1210 leukemia cells in vivo. In both cell models, the nanoformulation of Dox resulted in 100% cured animals already at low concentrations (0.1 mg/kg), while free Dox solely extended survival time. This indicates that the incorporation of phospholipids into PEGylated polymeric nanocarriers is a promising strategy to enhance efficacy and reduce toxicity of Dox treatment against both sensitive and resistant cancer models in vitro and in vivo.

  19. 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.

  20. 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

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

    Science.gov (United States)

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

    2017-09-09

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

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

    International Nuclear Information System (INIS)

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

    2010-01-01

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

  3. 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

    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...... 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-type...

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

    NARCIS (Netherlands)

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

    2007-01-01

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

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

    Science.gov (United States)

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

    2017-10-24

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

  6. Rapid emergence and mechanisms of resistance by U87 glioblastoma cells to doxorubicin in an in vitro tumor microfluidic ecology

    Science.gov (United States)

    Austin, Robert; Lee, Sanghyuk; Park, Sungsu

    We have developed a microfluidic device consisting of approximately 500 hexagonal micro-compartments which provides a complex ecology with wide ranges of drug and nutrient gradients and local populations. This ecology of a fragmented metapopulation induced the drug resistance in stage IV U87 glioblastoma cells to doxorubicin in seven days. Exome and transcriptome sequencing of the resistant cells identified mutations and differentially expressed genes. Gene ontology and pathway analyses of the genes identified showed that they were functionally relevant with the established mechanisms of doxorubicin action. Functional experiments support the in silico analyses and together demonstrate the effects of these genetic changes. Our findings suggest that given the rapid evolution of resistance and the focused response, this technology could act as a rapid screening modality for genetic aberrations leading to resistance to chemotherapy as well as counter-selection of drugs unlikely to be successful ultimately. Technology Innovation Program of the Ministry of Trade, Industry and Energy, Republic of Korea (10050154 to S.L. and S.P.), the National Research Foundation of Korea (NRF-2014M3C9A3065221 to S.L., NRF-2015K1A4A3047851 to J.K. and S.L.) funded by the Minis.

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

    Science.gov (United States)

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

    2017-01-17

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

  8. Overcoming drug resistance of MCF-7/ADR cells by altering intracellular distribution of doxorubicin via MVP knockdown with a novel siRNA polyamidoamine-hyaluronic acid complex.

    Science.gov (United States)

    Han, Min; Lv, Qing; Tang, Xin-Jiang; Hu, Yu-Lan; Xu, Dong-Hang; Li, Fan-Zhu; Liang, Wen-Quan; Gao, Jian-Qing

    2012-10-28

    Drug resistance is one of the critical reasons leading to failure in chemotherapy. Enormous studies have been focused on increasing intracellular drug accumulation through inhibiting P-glycoprotein (Pgp). Meanwhile, we found that major vault protein (MVP) may be also involved in drug resistance of human breast cancer MCF-7/ADR cells by transporting doxorubicin (DOX) from the action target (i.e. nucleus) to cytoplasma. Herein polyamidoamine (PAMAM) dendrimers was functionalized by a polysaccharide hyaluronic acid (HA) to effectively deliver DOX as well as MVP targeted small-interfering RNA (MVP-siRNA) to down regulate MVP expression and improve DOX chemotherapy in MCF-7/ADR cells. In comparison with DOX solution (IC50=48.5 μM), an enhanced cytotoxicity could be observed for DOX PAMAM-HA (IC50=11.3 μM) as well as enhanced tumor target, higher intracellular accumulation, increased blood circulating time and less in vivo toxicity. Furthermore, codelivery of siRNA and DOX by PAMAM-HA exhibited satisfactory gene silencing effect as well as enhanced stability and efficient intracellular delivery of siRNA, which allowed DOX access to nucleus and induced subsequent much more cytotoxicity than siRNA absent case as a result of MVP knockdown. This observation highlights a promising application of novel nanocarrier PAMAM-HA, which could co-deliver anticancer drug and siRNA, in reversing drug resistance by altering intracellular drug distribution. Copyright © 2012 Elsevier B.V. All rights reserved.

  9. Doxorubicin-loaded micelles of reverse poly(butylene oxide)-poly(ethylene oxide)-poly(butylene oxide) block copolymers as efficient "active" chemotherapeutic agents.

    Science.gov (United States)

    Cambón, A; Rey-Rico, A; Mistry, D; Brea, J; Loza, M I; Attwood, D; Barbosa, S; Alvarez-Lorenzo, C; Concheiro, A; Taboada, P; Mosquera, V

    2013-03-10

    Five reverse poly(butylene oxide)-poly(ethylene oxide)-poly(butylene oxide) block copolymers, BOnEOmBOn, with BO ranging from 8 to 21 units and EO from 90 to 411 were synthesized and evaluated as efficient chemotherapeutic drug delivery nanocarriers and inhibitors of the P-glycoprotein (P-gp) efflux pump in a multidrug resistant (MDR) cell line. The copolymers were obtained by reverse polymerization of poly(butylene oxide), which avoids transfer reaction and widening of the EO block distribution, commonly found in commercial poly(ethylene oxide)-poly(propylene oxide) block copolymers (poloxamers). BOnEOmBOn copolymers formed spherical micelles of 10-40 nm diameter at lower concentrations (one order of magnitude) than those of equivalent poloxamers. The influence of copolymer block lengths and BO/EO ratios on the solubilization capacity and protective environment for doxorubicin (DOXO) was investigated. Micelles showed drug loading capacity ranging from ca. 0.04% to 1.5%, more than 150 times the aqueous solubility of DOXO, and protected the cargo from hydrolysis for more than a month due to their greater colloidal stability in solution. Drug release profiles at various pHs, and the cytocompatibility and cytotoxicity of the DOXO-loaded micelles were assessed in vitro. DOXO loaded in the polymeric micelles accumulated more slowly inside the cells than free DOXO due to its sustained release. All copolymers were found to be cytocompatible, with viability extents larger than 95%. In addition, the cytotoxicity of DOXO-loaded micelles was higher than that observed for free drug solutions in a MDR ovarian NCI-ADR-RES cell line which overexpressed P-gp. The inhibition of the P-gp efflux pump by some BOnEOmBOn copolymers, similar to that measured for the common P-gp inhibitor verapamil, favored the retention of DOXO inside the cell increasing its cytotoxic activity. Therefore, poly(butylene oxide)-poly(ethylene oxide) block copolymers offer interesting features as cell

  10. 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

  11. The different expression of TRPM7 and MagT1 impacts on the proliferation of colon carcinoma cells sensitive or resistant to doxorubicin

    OpenAIRE

    Cazzaniga, Alessandra; Moscheni, Claudia; Trapani, Valentina; Wolf, Federica I.; Farruggia, Giovanna; Sargenti, Azzurra; Iotti, Stefano; Maier, Jeanette A. M.; Castiglioni, Sara

    2017-01-01

    The processes leading to anticancer drug resistance are not completely unraveled. To get insights into the underlying mechanisms, we compared colon carcinoma cells sensitive to doxorubicin with their resistant counterpart. We found that resistant cells are growth retarded, and show staminal and ultrastructural features profoundly different from sensitive cells. The resistant phenotype is accompanied by the upregulation of the magnesium transporter MagT1 and the downregulation of the ion chann...

  12. Doxorubicin impairs the insulin-like growth factor-1 system and causes insulin-like growth factor-1 resistance in cardiomyocytes.

    Directory of Open Access Journals (Sweden)

    Patrizia Fabbi

    Full Text Available Insulin-like growth factor-1 (IGF-1 promotes the survival of cardiomyocytes by activating type 1 IGF receptor (IGF-1R. Within the myocardium, IGF-1 action is modulated by IGF binding protein-3 (IGFBP-3, which sequesters IGF-1 away from IGF-1R. Since cardiomyocyte apoptosis is implicated in anthracycline cardiotoxicity, we investigated the effects of the anthracycline, doxorubicin, on the IGF-1 system in H9c2 cardiomyocytes.Besides inducing apoptosis, concentrations of doxorubicin comparable to those observed in patients after bolus infusion (0.1-1 µM caused a progressive decrease in IGF-1R and increase in IGFBP-3 expression. Exogenous IGF-1 was capable to rescue cardiomyocytes from apoptosis triggered by 0.1 and 0.5 µM, but not 1 µM doxorubicin. The loss of response to IGF-1 was paralleled by a significant reduction in IGF-1 availability and signaling, as assessed by free hormone levels in conditioned media and Akt phosphorylation in cell lysates, respectively. Doxorubicin also dose-dependently induced p53, which is known to repress the transcription of IGF1R and induce that of IGFBP3. Pre-treatment with the p53 inhibitor, pifithrin-α, prevented apoptosis and the changes in IGF-1R and IGFBP-3 elicited by doxorubicin. The decrease in IGF-1R and increase in IGFBP-3, as well as apoptosis, were also antagonized by pre-treatment with the antioxidant agents, N-acetylcysteine, dexrazoxane, and carvedilol.Doxorubicin down-regulates IGF-1R and up-regulates IGFBP-3 via p53 and oxidative stress in H9c2 cells. This leads to resistance to IGF-1 that may contribute to doxorubicin-initiated apoptosis. Further studies are needed to confirm these findings in human cardiomyocytes and explore the possibility of manipulating the IGF-1 axis to protect against anthracycline cardiotoxicity.

  13. 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

  14. 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.

  15. Doxorubicin-induced mitophagy contributes to drug resistance in cancer stem cells from HCT8 human colorectal cancer cells.

    Science.gov (United States)

    Yan, Chen; Luo, Lan; Guo, Chang-Ying; Goto, Shinji; Urata, Yoshishige; Shao, Jiang-Hua; Li, Tao-Sheng

    2017-03-01

    Cancer stem cells (CSCs) are known to be drug resistant. Mitophagy selectively degrades unnecessary or damaged mitochondria by autophagy during cellular stress. To investigate the potential role of mitophagy in drug resistance in CSCs, we purified CD133 + /CD44 + CSCs from HCT8 human colorectal cancer cells and then exposed to doxorubicin (DXR). Compared with parental cells, CSCs were more resistant to DXR treatment. Although DXR treatment enhanced autophagy levels in both cell types, the inhibition of autophagy by ATG7 silencing significantly increased the toxicity of DXR only in parental cells, not in CSCs. Interestingly, the level of mitochondrial superoxide was detected to be significantly lower in CSCs than in parental cells after DXR treatment. Furthermore, the mitophagy level and expression of BNIP3L, a mitophagy regulator, were significantly higher in CSCs than in parental cells after DXR treatment. Silencing BNIP3L significantly halted mitophagy and enhanced the sensitivity to DXR in CSCs. Our data suggested that mitophagy, but not non-selective autophagy, likely contributes to drug resistance in CSCs isolated from HCT8 cells. Further studies in other cancer cell lines will be needed to confirm our findings. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  16. Chemomodulation of Doxorubicin Pharmacodynamics

    Science.gov (United States)

    2002-10-01

    doxorubicin in athymic nude mice with multidrug resistant MCF-7 human tumor xenografts. High pressure liquid chromatography ( HPLC ) will be utilized to measure...is a flavonoid that causes 50% growth tumor growth support by the host (42). The clinical efficacy of inhibition of tumor cells at 60 nM (57). It also

  17. 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 (Δlog 10 CFU per milliliter [CFU/ml] of 8 log units after 24 h), and the in vivo efficacy of ciprofloxacin was significantly enhanced (Δlog 10 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

  18. 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.

  19. Circumvention of multidrug resistance and reduction of cardiotoxicity of doxorubicin in vivo by coupling it with low density lipoprotein.

    Science.gov (United States)

    Lo, Elka H K; Ooi, Vincent E L; Fung, K P

    2002-12-27

    Doxorubicin (Dox) was coupled into human low density lipoprotein (LDL) to form a complex LDL-Dox. In in vitro studies, the accumulation of LDL-Dox in human resistant hepatoma (R-HepG2) cells was found to be higher than that of free Dox in the cells, resulting in an increase of the cytotoxic effect on the cells. Moreover, in in vivo studies, under the same dosage of drugs (1 mg/kg), the anti-proliferative effect on the tumor cells of LDL-Dox in nude mice bearing R-HepG2 cells was higher than that of free Dox as evidenced by the larger reduction in tumor volumes and tumor weights in LDL-Dox treated group. Histological studies showed that LDL-Dox treatment did not cause any heart damage when compared with the control group. In contrast, Dox treatment caused disruption and vacuolization of myocardial filament. Plasma lactate dehydrogenase activity and plasma creatine kinase activity in nude mice bearing R-HepG2 cells were found to be elevated in the Dox-treated group but remained unchanged in LDL-Dox-treated group. The present studies indicate that when Dox is coupled with LDL, the multidrug resistance can be circumvented and the cardiotoxicity can be reduced.

  20. Consumption of Fresh Yellow Onion Ameliorates Hyperglycemia and Insulin Resistance in Breast Cancer Patients During Doxorubicin-Based Chemotherapy: A Randomized Controlled Clinical Trial.

    Science.gov (United States)

    Jafarpour-Sadegh, Farnaz; Montazeri, Vahid; Adili, Ali; Esfehani, Ali; Rashidi, Mohammad-Reza; Pirouzpanah, Saeed

    2017-09-01

    Doxorubicin has been found to be associated with insulin resistance in animal models. Onion, a so-called functional food, is noted to affect the insulin signaling pathway of diabetes in vitro. To our knowledge, this is the first study to investigate the effects of consuming fresh yellow onions on insulin-related indices compared with a low-onion-containing diet among breast cancer (BC) patients treated with doxorubicin. This parallel-design, randomized, triple-blind, controlled clinical trial was conducted on 56 eligible BC patients (aged 30-63 years), diagnosed with invasive ductal carcinoma. Following their second cycle of chemotherapy, subjects were assigned in a stratified-random allocation to receive body mass index-dependent 100 to 160 g/d of onion as high onion group (HO; n = 28) or 30 to 40 g/d small onions in low onion group (LO; n = 28) for 8 weeks intervention. Participants, care givers, and those who assessed laboratory analyses were blinded to the assignments (IRCT Registry No.: IRCT2012103111335N1). The compliance level of participants in the analysis was as high as 87.85%. A total of 23 available cases was analyzed in each group. The daily use of HO resulted in a significant decrease in serum fasting blood glucose and insulin levels in comparison with LO, over the period of study ( P insulin resistance relative to changes in the LO group ( P insulin sensitivity check index ( P insulin resistance in BC during doxorubicin-based chemotherapy.

  1. 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

  2. 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.

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

    Science.gov (United States)

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

    2017-01-01

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

  4. 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.

  5. The different expression of TRPM7 and MagT1 impacts on the proliferation of colon carcinoma cells sensitive or resistant to doxorubicin.

    Science.gov (United States)

    Cazzaniga, Alessandra; Moscheni, Claudia; Trapani, Valentina; Wolf, Federica I; Farruggia, Giovanna; Sargenti, Azzurra; Iotti, Stefano; Maier, Jeanette A M; Castiglioni, Sara

    2017-01-17

    The processes leading to anticancer drug resistance are not completely unraveled. To get insights into the underlying mechanisms, we compared colon carcinoma cells sensitive to doxorubicin with their resistant counterpart. We found that resistant cells are growth retarded, and show staminal and ultrastructural features profoundly different from sensitive cells. The resistant phenotype is accompanied by the upregulation of the magnesium transporter MagT1 and the downregulation of the ion channel kinase TRPM7. We demonstrate that the different amounts of TRPM7 and MagT1 account for the different proliferation rate of sensitive and resistant colon carcinoma cells. It remains to be verified whether they are also involved in the control of other "staminal" traits.

  6. [Computational prediction of human immunodeficiency resistance to reverse transcriptase inhibitors].

    Science.gov (United States)

    Tarasova, O A; Filimonov, D A; Poroikov, V V

    2017-10-01

    Human immunodeficiency virus (HIV) causes acquired immunodeficiency syndrome (AIDS) and leads to over one million of deaths annually. Highly active antiretroviral treatment (HAART) is a gold standard in the HIV/AIDS therapy. Nucleoside and non-nucleoside inhibitors of HIV reverse transcriptase (RT) are important component of HAART, but their effect depends on the HIV susceptibility/resistance. HIV resistance mainly occurs due to mutations leading to conformational changes in the three-dimensional structure of HIV RT. The aim of our work was to develop and test a computational method for prediction of HIV resistance associated with the mutations in HIV RT. Earlier we have developed a method for prediction of HIV type 1 (HIV-1) resistance; it is based on the usage of position-specific descriptors. These descriptors are generated using the particular amino acid residue and its position; the position of certain residue is determined in a multiple alignment. The training set consisted of more than 1900 sequences of HIV RT from the Stanford HIV Drug Resistance database; for these HIV RT variants experimental data on their resistance to ten inhibitors are presented. Balanced accuracy of prediction varies from 80% to 99% depending on the method of classification (support vector machine, Naive Bayes, random forest, convolutional neural networks) and the drug, resistance to which is obtained. Maximal balanced accuracy was obtained for prediction of resistance to zidovudine, stavudine, didanosine and efavirenz by the random forest classifier. Average accuracy of prediction is 89%.

  7. Targeting protein kinases to reverse multidrug resistance in sarcoma.

    Science.gov (United States)

    Chen, Hua; Shen, Jacson; Choy, Edwin; Hornicek, Francis J; Duan, Zhenfeng

    2016-02-01

    Sarcomas are a group of cancers that arise from transformed cells of mesenchymal origin. They can be classified into over 50 subtypes, accounting for approximately 1% of adult and 15% of pediatric cancers. Wide surgical resection, radiotherapy, and chemotherapy are the most common treatments for the majority of sarcomas. Among these therapies, chemotherapy can palliate symptoms and prolong life for some sarcoma patients. However, sarcoma cells can have intrinsic or acquired resistance after treatment with chemotherapeutics drugs, leading to the development of multidrug resistance (MDR). MDR attenuates the efficacy of anticancer drugs and results in treatment failure for sarcomas. Therefore, overcoming MDR is an unmet need for sarcoma therapy. Certain protein kinases demonstrate aberrant expression and/or activity in sarcoma cells, which have been found to be involved in the regulation of sarcoma cell progression, such as cell cycle, apoptosis, and survival. Inhibiting these protein kinases may not only decrease the proliferation and growth of sarcoma cells, but also reverse their resistance to chemotherapeutic drugs to subsequently reduce the doses of anticancer drugs and decrease drug side-effects. The discovery of novel strategies targeting protein kinases opens a door to a new area of sarcoma research and provides insight into the mechanisms of MDR in chemotherapy. This review will focus on the recent studies in targeting protein kinase to reverse chemotherapeutic drug resistance in sarcoma. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Cytotoxicity and cellular uptake of doxorubicin and its formamidine derivatives in HL60 sensitive and HL60/MX2 resistant cells.

    Science.gov (United States)

    Kik, Krzysztof; Wasowska-Lukawska, Malgorzata; Oszczapowicz, Irena; Szmigiero, Leszek

    2009-04-01

    In this work a comparison was made of the cytotoxicity and cellular uptake of doxorubicin (DOX) and two of its derivatives containing a formamidino group (-N=CH-N<) at the 3' position with morpholine (DOXM) or hexamethyleneimine (DOXH) ring. All tests were performed in doxorubicin-sensitive HL60 and -resistant HL60/MX2 cells which are known for the presence of altered topoisomerase II. Cytotoxic activity of DOX toward HL60/MX2 cells was about 195 times lower when compared with the sensitive HL60 cell line. DOXM and DOXH were approximately 20 times more active in resistant cells than DOX. It was found that the uptake of DOX was lower in resistant cells by about 16%, while that of DOXM and DOXH was lower by about 36% and 19%, respectively. Thus the changes in the cellular uptake of anthracyclines are not associated with the fact that cytotoxicity of DOXM and DOXH exceed the cytotoxicity of DOX. Experiments in cell-free system containing human topoisomerase II showed that topoisomerase II is not inhibited by DOXM and DOXH. Formamidinoanthracyclines may be more useful than parent drugs in therapy against tumor cells with altered topoisomerase II activity.

  9. 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.

  10. Reversal of methicillin resistance in Staphylococcus aureus by thioridazine

    DEFF Research Database (Denmark)

    Klitgaard, Janne K; Skov, Marianne N; Kallipolitis, Birgitte H

    2008-01-01

    of thioridazine in the presence of a fixed amount of oxacillin. Furthermore, the protein level of PBP2a was reduced when bacteria were treated with the combination of oxacillin and thioridazine. The two drugs also affected the mRNA level of the beta-lactamase gene, blaZ. Conclusions The present study indicates......Objectives Thioridazine has been shown to reverse oxacillin resistance in methicillin-resistant Staphylococcus aureus (MRSA) in vitro. The aim of this study was to investigate whether thioridazine alone or in combination with oxacillin affects the transcription of the methicillin resistance gene...... blotting in the presence of thioridazine and oxacillin. Results We observed an increased susceptibility of MRSA towards oxacillin in the presence of thioridazine compared with bacteria grown with oxacillin or thioridazine alone. Transcription of mecA was reduced with increasing concentrations...

  11. 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

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

    Directory of Open Access Journals (Sweden)

    Doublier Sophie

    2012-01-01

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

  13. Resistive m=o mode in reverse-field configurations

    International Nuclear Information System (INIS)

    Galvao, R.M.O.; Santiago, M.A.M.

    1982-01-01

    The resistive m=0 mode is studied. Where m is the azimuthal mode number in magnetic confinement configurations with parallel field lines such that the magnetic field reverses direction inside the plasma. A cylindrical plasma column which rotates rigidly with a rotation velocity Ω is considered. It is found that the growth rate of the mode γ scales differently with the plasma resistivity depending on whether Ω vanishes or not; γα sup(3/5) for Ω=0 and γα sup(1/3) for Ω different 0. When the Hall term is also included in the generalized Ohm's law, γα sup(1/2) is obtained. This last result is in disagreement with the results of Krappraff et al. (Author) [pt

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

    Science.gov (United States)

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

    2017-01-01

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

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

    Science.gov (United States)

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

    2012-07-01

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

  16. 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.

  17. Comparative study on reversal efficacy of SDZ PSC 833, cyclosporin a and verapamil on multidrug resistance in vitro and in vivo

    International Nuclear Information System (INIS)

    Watanabe, Toru; Tsuge, Harumi; Oh-Hara, Tomoko; Naito, Mikihiko; Tsuruo, Takashi

    1995-01-01

    A non-immunosuppressive cyclosporin, SDZ PSC 833 (PSC833), shows a reversal effect on multidrug resistance (MDR) by functional modulation of MDR1 gene product, P-glycoprotein. The objective of the present study was to compare the reversal efficacy of three multidrug resistance modulators, PSC833, cyclosporin A (CsA) and verapamil (Vp). PSC833 has approximately 3-10-fold greater potency than CsA and Vp with respect to the restoring effect on reduced accumulation of doxorubicin (ADM) and vincristine (VCR) in ADM-resistant K562 myelogenous leukemia cells (K562/ADM) in vitro and also on the sensitivity of K562/ADM to ADM and VCR in in vitro growth inhibition. The in vivo efficacy of a combination of modifiers (PSC833 and CsA: 50 mg/kg, Vp 100 mg/kg administered p.o. 4 h before the administration of anticancer drugs) with anticancer drugs (ADM 2.5 mg/kg i.p., Q4D days 1, 5 and 9, VCR 0.05 mg/kg i.p., QD days 1-5) was tested in ADM-resistant P388-bearing mice. PSC833 significantly enhanced the increase in life span by more than 80%, whereas CsA and Vp enhanced by less than 50%. This reversal potency, which exceeded that of CsA and Vp, was confirmed by therapeutic experiments using colon adenocarcinoma 26-bearing mice. These results demonstrated that PSC833 has significant potency to reverse MDR in vitro and in vivo, suggesting that PSC833 is a good candidate for reversing multidrug resistance in clinical situations. (orig.)

  18. Reversal of P-glycoprotein-medicated multidrug resistance by LBM-A5 in vitro and a study of its pharmacokinetics in vivo.

    Science.gov (United States)

    Zhao, Tianxiao; Song, Yun; Liu, Baomin; Qiu, Qianqian; Jiao, Lei; Li, Yunman; Huang, Wenlong; Qian, Hai

    2015-01-01

    The overexpression of P-glycoprotein (P-gp) in tumors leads to multidrug resistance (MDR), which is a significant obstacle in clinical cancer chemotherapy. The co-administration of anticancer drugs and MDR modulators is a promising strategy for overcoming this problem. Our study aimed to explore the reversal mechanism and safety of the MDR modulator LBM-A5 in vitro, and evaluate its pharmacokinetics and effects on doxorubicin metabolism in vivo. We evaluated an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay of anticancer agents mediated by LBM-A5, the effect of LBM-A5 on rhodamine123 intracellular accumulation, and the efflux in K562/DOX cells to investigate the reversal mechanisms of LBM-A5. The results showed that LBM-A5 inhibits rhodamine123 efflux and increases intracellular accumulation by inhibiting the efflux pump function of P-gp. Furthermore, the therapeutic index and CYP3A4 activity analysis in vitro suggested that LBM-A5 is reasonably safe to use. Also, LBM-A5 (10 mg/kg body mass) achieved the required plasma concentration in sufficient time to reverse MDR in vivo. Importantly, the LBM-A5 treatment group shared similar doxorubicin (DOX) pharmacokinetics with the free DOX group. Our results suggest that LBM-A5 effectively reverses MDR (EC50 = 483.6 ± 81.7 nmol·L(-1)) by inhibiting the function of P-gp, with relatively ideal pharmacokinetics and in a safe manner, and so may be a promising candidate for cancer chemotherapy research.

  19. 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.

  20. Bafetinib (INNO-406) reverses multidrug resistance by inhibiting the efflux function of ABCB1 and ABCG2 transporters

    Science.gov (United States)

    Zhang, Yun-Kai; Zhang, Guan-Nan; Wang, Yi-Jun; Patel, Bhargav A.; Talele, Tanaji T.; Yang, Dong-Hua; Chen, Zhe-Sheng

    2016-05-01

    ATP-Binding Cassette transporters are involved in the efflux of xenobiotic compounds and are responsible for decreasing drug accumulation in multidrug resistant (MDR) cells. Discovered by structure-based virtual screening algorithms, bafetinib, a Bcr-Abl/Lyn tyrosine kinase inhibitor, was found to have inhibitory effects on both ABCB1- and ABCG2-mediated MDR in this in-vitro investigation. Bafetinib significantly sensitized ABCB1 and ABCG2 overexpressing MDR cells to their anticancer substrates and increased the intracellular accumulation of anticancer drugs, particularly doxorubicin and [3H]-paclitaxel in ABCB1 overexpressing cells; mitoxantrone and [3H]-mitoxantrone in ABCG2 overexpressing cells, respectively. Bafetinib stimulated ABCB1 ATPase activities while inhibited ABCG2 ATPase activities. There were no significant changes in the expression level or the subcellular distribution of ABCB1 and ABCG2 in the cells exposed to 3 μM of bafetinib. Overall, our study indicated that bafetinib reversed ABCB1- and ABCG2-mediated MDR by blocking the drug efflux function of these transporters. These findings might be useful in developing combination therapy for MDR cancer treatment.

  1. pH-Dependent doxorubicin release from terpolymer of starch, polymethacrylic acid and polysorbate 80 nanoparticles for overcoming multi-drug resistance in human breast cancer cells.

    Science.gov (United States)

    Shalviri, Alireza; Raval, Gaurav; Prasad, Preethy; Chan, Carol; Liu, Qiang; Heerklotz, Heiko; Rauth, Andrew Michael; Wu, Xiao Yu

    2012-11-01

    This work investigated the capability of a new nanoparticulate system, based on terpolymer of starch, polymethacrylic acid and polysorbate 80, to load and release doxorubicin (Dox) as a function of pH and to evaluate the anticancer activity of Dox-loaded nanoparticles (Dox-NPs) to overcome multidrug resistance (MDR) in human breast cancer cells in vitro. The Dox-NPs were characterized by Fourier transform infrared spectroscopy (FTIR), isothermal titration calorimetry (ITC), transmission electron microscopy (TEM), and dynamic light scattering (DLS). The cellular uptake and cytotoxicity of the Dox-loaded nanoparticles were investigated using fluorescence microscopy, flow cytometry, and a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) (MTT) assay. The nanoparticles were able to load up to 49.7±0.3% of Dox with a high loading efficiency of 99.9±0.1%, while maintaining good colloidal stability. The nanoparticles released Dox at a higher rate at acidic pH attributable to weaker Dox-polymer molecular interactions evidenced by ITC. The Dox-NPs were taken up by the cancer cells in vitro and significantly enhanced the cytotoxicity of Dox against human MDR1 cells with up to a 20-fold decrease in the IC50 values. The results suggest that the new terpolymeric nanoparticles are a promising vehicle for the controlled delivery of Dox for treatment of drug resistant breast cancer. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. Modulation in vitro and in vivo of cytotoxicity but not cellular levels of doxorubicin by the calmodulin inhibitor trifluoperazine is dependent on the level of resistance.

    Science.gov (United States)

    Ganapathi, R.; Schmidt, H.; Grabowski, D.; Melia, M.; Ratliff, N.

    1988-01-01

    The role of the calmodulin inhibitor trifluoperazine (TFP) in modulating the cellular levels and cytotoxicity in vitro and antitumour effects in vivo of doxorubicin (DOX), was evaluated in progressively DOX-resistant (5- to 40-fold) sublines of B16-BL6 mouse melanoma. In parental-sensitive B16-BL6 cells treated for 3 h, the IC50 of DOX was 0.1 microgram ml-1, and a less than 2-fold enhancement in DOX cell kill in the presence of a noncytotoxic concentration of 5 microM TFP was observed. However, in the DOX-resistant sublines, the IC50 was 0.7 to 5.0 micrograms ml-1 DOX in the absence of 5 microM TFP and 0.3 to 0.7 microgram ml-1 DOX in the presence of 5 microM TFP. The 2- to 7.5-fold decrease in the IC50 of DOX in the presence of 5 microM TFP, was dependent on the level of DOX-resistance in the various sublines. Compared to parental-sensitive cells, a 2-fold decrease in DOX-accumulation was evident only in the 40-fold DOX-resistant subline. Further, maximal enhancement (50%) of cellular DOX accumulation in the presence of 5 microM TFP was observed only in the 40-fold resistant cells treated with 5.0 micrograms ml-1 DOX. Retention of DOX in the 40-fold resistant subline was only 20% lower than similarly treated sensitive cells, and the inclusion of TFP increased DOX retention less than 10-15%. Antitumour studies in mice with experimental pulmonary metastases revealed that although DOX and DOX plus TFP had similar antitumour activity with the parental sensitive B16-BL6 cells, the combination of DOX plus TFP was significantly more effective than DOX alone with the DOX-resistant sublines. No overt toxicity was observed in normal mice treated with doses of TFP, DOX or DOX plus TFP used for in vivo chemotherapy studies. Results from this study suggest that gross cellular DOX levels do not appear to correlate with the magnitude of resistance, and the effects of TFP in modulating DOX resistance is possibly due to mechanisms other than mere alterations in cellular drug

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

    International Nuclear Information System (INIS)

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

    2006-01-01

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

  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. Salt Concentration Differences Alter Membrane Resistance in Reverse Electrodialysis Stacks

    KAUST Repository

    Geise, Geoffrey M.; Curtis, Andrew J.; Hatzell, Marta C.; Hickner, Michael A.; Logan, Bruce E.

    2014-01-01

    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

  6. 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...

  7. pH- and NIR Light-Responsive Polymeric Prodrug Micelles for Hyperthermia-Assisted Site-Specific Chemotherapy to Reverse Drug Resistance in Cancer Treatment.

    Science.gov (United States)

    Li, Zuhong; Wang, Haibo; Chen, Yangjun; Wang, Yin; Li, Huan; Han, Haijie; Chen, Tingting; Jin, Qiao; Ji, Jian

    2016-05-01

    Despite the exciting advances in cancer chemotherapy over past decades, drug resistance in cancer treatment remains one of the primary reasons for therapeutic failure. IR-780 loaded pH-responsive polymeric prodrug micelles with near infrared (NIR) photothermal effect are developed to circumvent the drug resistance in cancer treatment. The polymeric prodrug micelles are stable in physiological environment, while exhibit fast doxorubicin (DOX) release in acidic condition and significant temperature elevation under NIR laser irradiation. Phosphorylcholine-based biomimetic micellar shell and acid-sensitive drug conjugation endow them with prolonged circulation time and reduced premature drug release during circulation to conduct tumor site-specific chemotherapy. The polymeric prodrug micelles combined with NIR laser irradiation could significantly enhance intracellular DOX accumulation and synergistically induce the cell apoptosis in DOX-resistant MCF-7/ADR cells. Meanwhile, the tumor site-specific chemotherapy combined with hyperthermia effect induces significant inhibition of MCF-7/ADR tumor growth in tumor-bearing mice. These results demonstrate that the well-designed IR-780 loaded polymeric prodrug micelles for hyperthermia-assisted site-specific chemotherapy present an effective approach to reverse drug resistance. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. 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.

  9. 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.

  10. 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...

  11. Protective effects of agmatine on doxorubicin-induced chronic cardiotoxicity in rat.

    Science.gov (United States)

    Yarmohmmadi, Fatemeh; Rahimi, Nastaran; Faghir-Ghanesefat, Hedyeh; Javadian, Nina; Abdollahi, Alireza; Pasalar, Parvin; Jazayeri, Farahnaz; Ejtemaeemehr, Shahram; Dehpour, Ahmad Reza

    2017-02-05

    The detrimental cardio-toxic effect of doxorubicin, an effective chemotherapeutic agent, limited its clinical use. It has been claimed that doxorubicin cardio-toxicity occurs through calcium ions (Ca 2+ ) overload and reactive oxygen species production. Agmatine, an endogenous imidazoline receptor agonist, induce uptake of cytosolic Ca 2+ and cause an increase in activity of calcium pumps, including Ca 2+ -ATPase. Also it shows self-scavenging effect against reactive oxygen species production. Therefore, present study was designed to investigate the effects of agmatine against chronic cardio-toxicity of doxorubicin in rats. Male wistar rats were intraperitoneally injected with doxorubicin and agmatine four times a week for a month. Agmatine significantly alleviate the adverse effect of doxorubicin on left ventricular papillary muscle stimulation threshold and contractibility. Chronic co-administration of agmatine with doxorubicin blocked electrocardiographic changes induced by doxorubicin. In addition, agmatine improved body weight and decreased the mortality rate of animals by doxorubicin. Moreover, reversing the doxorubicin induced myocardial lesions was observed in animals treated by agmatine. A significant rise in the total antioxidant capacity of rat plasma was achieved in agmatine-treated animals in comparison to doxorubicin. To conclude, agmatine may improve therapeutic outcomes of doxorubicin since it exerts protective effects against doxorubicin-induced chronic cardiotoxicity in rats. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. The reversal effects of 3-bromopyruvate on multidrug resistance in vitro and in vivo derived from human breast MCF-7/ADR cells.

    Directory of Open Access Journals (Sweden)

    Long Wu

    Full Text Available P-glycoprotein mediated efflux is one of the main mechanisms for multidrug resistance in cancers, and 3-Bromopyruvate acts as a promising multidrug resistance reversal compound in our study. To test the ability of 3-Bromopyruvate to overcome P-glycoprotein-mediated multidrug resistance and to explore its mechanisms of multidrug resistance reversal in MCF-7/ADR cells, we evaluate the in vitro and in vivo modulatory activity of this compound.The in vitro and in vivo activity was determined using the MTT assay and human breast cancer xenograft models. The gene and protein expression of P-glycoprotein were determined using real-time polymerase chain reaction and the Western blotting technique, respectively. ABCB-1 bioactivity was tested by fluorescence microscopy, multi-mode microplate reader, and flow cytometry. The intracellular levels of ATP, HK-II, and ATPase activity were based on an assay kit according to the manufacturer's instructions.3-Bromopyruvate treatment led to marked decreases in the IC50 values of selected chemotherapeutic drugs [e.g., doxorubicin (283 folds, paclitaxel (85 folds, daunorubicin (201 folds, and epirubicin (171 folds] in MCF-7/ADR cells. 3-Bromopyruvate was found also to potentiate significantly the antitumor activity of epirubicin against MCF-7/ADR xenografts. The intracellular level of ATP decreased 44%, 46% in the presence of 12.5.25 µM 3-Bromopyruvate, whereas the accumulation of rhodamine 123 and epirubicin (two typical P-glycoprotein substrates in cells was significantly increased. Furthermore, we found that the mRNA and the total protein level of P-glycoprotein were slightly altered by 3-Bromopyruvate. Moreover, the ATPase activity was significantly inhibited when 3-Bromopyruvate was applied.We demonstrated that 3-Bromopyruvate can reverse P-glycoprotein-mediated efflux in MCF-7/ADR cells. Multidrug resistance reversal by 3-Bromopyruvate occurred through at least three approaches, namely, a decrease in the

  13. The reversal effects of 3-bromopyruvate on multidrug resistance in vitro and in vivo derived from human breast MCF-7/ADR cells.

    Science.gov (United States)

    Wu, Long; Xu, Jun; Yuan, Weiqi; Wu, Baojian; Wang, Hao; Liu, Guangquan; Wang, Xiaoxiong; Du, Jun; Cai, Shaohui

    2014-01-01

    P-glycoprotein mediated efflux is one of the main mechanisms for multidrug resistance in cancers, and 3-Bromopyruvate acts as a promising multidrug resistance reversal compound in our study. To test the ability of 3-Bromopyruvate to overcome P-glycoprotein-mediated multidrug resistance and to explore its mechanisms of multidrug resistance reversal in MCF-7/ADR cells, we evaluate the in vitro and in vivo modulatory activity of this compound. The in vitro and in vivo activity was determined using the MTT assay and human breast cancer xenograft models. The gene and protein expression of P-glycoprotein were determined using real-time polymerase chain reaction and the Western blotting technique, respectively. ABCB-1 bioactivity was tested by fluorescence microscopy, multi-mode microplate reader, and flow cytometry. The intracellular levels of ATP, HK-II, and ATPase activity were based on an assay kit according to the manufacturer's instructions. 3-Bromopyruvate treatment led to marked decreases in the IC50 values of selected chemotherapeutic drugs [e.g., doxorubicin (283 folds), paclitaxel (85 folds), daunorubicin (201 folds), and epirubicin (171 folds)] in MCF-7/ADR cells. 3-Bromopyruvate was found also to potentiate significantly the antitumor activity of epirubicin against MCF-7/ADR xenografts. The intracellular level of ATP decreased 44%, 46% in the presence of 12.5.25 µM 3-Bromopyruvate, whereas the accumulation of rhodamine 123 and epirubicin (two typical P-glycoprotein substrates) in cells was significantly increased. Furthermore, we found that the mRNA and the total protein level of P-glycoprotein were slightly altered by 3-Bromopyruvate. Moreover, the ATPase activity was significantly inhibited when 3-Bromopyruvate was applied. We demonstrated that 3-Bromopyruvate can reverse P-glycoprotein-mediated efflux in MCF-7/ADR cells. Multidrug resistance reversal by 3-Bromopyruvate occurred through at least three approaches, namely, a decrease in the intracellular

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

    International Nuclear Information System (INIS)

    Aguilar, David; Strom, Joshua; Chen, Qin M.

    2014-01-01

    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

  15. Structure-based methods to predict mutational resistance to diarylpyrimidine non-nucleoside reverse transcriptase inhibitors.

    Science.gov (United States)

    Azeem, Syeda Maryam; Muwonge, Alecia N; Thakkar, Nehaben; Lam, Kristina W; Frey, Kathleen M

    2018-01-01

    Resistance to non-nucleoside reverse transcriptase inhibitors (NNRTIs) is a leading cause of HIV treatment failure. Often included in antiviral therapy, NNRTIs are chemically diverse compounds that bind an allosteric pocket of enzyme target reverse transcriptase (RT). Several new NNRTIs incorporate flexibility in order to compensate for lost interactions with amino acid conferring mutations in RT. Unfortunately, even successful inhibitors such as diarylpyrimidine (DAPY) inhibitor rilpivirine are affected by mutations in RT that confer resistance. In order to aid drug design efforts, it would be efficient and cost effective to pre-evaluate NNRTI compounds in development using a structure-based computational approach. As proof of concept, we applied a residue scan and molecular dynamics strategy using RT crystal structures to predict mutations that confer resistance to DAPYs rilpivirine, etravirine, and investigational microbicide dapivirine. Our predictive values, changes in affinity and stability, are correlative with fold-resistance data for several RT mutants. Consistent with previous studies, mutation K101P is predicted to confer high-level resistance to DAPYs. These findings were further validated using structural analysis, molecular dynamics, and an enzymatic reverse transcription assay. Our results confirm that changes in affinity and stability for mutant complexes are predictive parameters of resistance as validated by experimental and clinical data. In future work, we believe that this computational approach may be useful to predict resistance mutations for inhibitors in development. Published by Elsevier Inc.

  16. 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.

  17. Reversing Bacterial Resistance to Antibiotics by Phage-Mediated Delivery of Dominant Sensitive Genes

    OpenAIRE

    Edgar, Rotem; Friedman, Nir; Molshanski-Mor, Shahar; Qimron, Udi

    2012-01-01

    Pathogen resistance to antibiotics is a rapidly growing problem, leading to an urgent need for novel antimicrobial agents. Unfortunately, development of new antibiotics faces numerous obstacles, and a method that resensitizes pathogens to approved antibiotics therefore holds key advantages. We present a proof of principle for a system that restores antibiotic efficiency by reversing pathogen resistance. This system uses temperate phages to introduce, by lysogenization, the genes rpsL and gyrA...

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

    Science.gov (United States)

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

    2018-01-01

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

  19. Pleotropic effects of leptin to reverse insulin resistance and diabetic ketoacidosis

    DEFF Research Database (Denmark)

    Perry, Rachel J; Petersen, Kitt Falk; Shulman, Gerald I.

    2016-01-01

    In this review we discuss the mechanisms for the pleotropic effects of leptin replacement therapy to reverse liver and muscle insulin resistance in lipodystrophic individuals, as well as insulin-independent effects of leptin replacement therapy to suppress white adipose tissue lipolysis, hepatic...

  20. 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.

  1. C-Cbl reverses HER2-mediated tamoxifen resistance in human breast cancer cells.

    Science.gov (United States)

    Li, Wei; Xu, Ling; Che, Xiaofang; Li, Haizhou; Zhang, Ye; Song, Na; Wen, Ti; Hou, Kezuo; Yang, Yi; Zhou, Lu; Xin, Xing; Xu, Lu; Zeng, Xue; Shi, Sha; Liu, Yunpeng; Qu, Xiujuan; Teng, Yuee

    2018-05-02

    Tamoxifen is a frontline therapy for estrogen receptor (ER)-positive breast cancer in premenopausal women. However, many patients develop resistance to tamoxifen, and the mechanism underlying tamoxifen resistance is not well understood. Here we examined whether ER-c-Src-HER2 complex formation is involved in tamoxifen resistance. MTT and colony formation assays were used to measure cell viability and proliferation. Western blot was used to detect protein expression and protein complex formations were detected by immunoprecipitation and immunofluorescence. SiRNA was used to examine the function of HER2 in of BT474 cells. An in vivo xenograft animal model was established to examine the role of c-Cbl in tumor growth. MTT and colony formation assay showed that BT474 cells are resistant to tamoxifen and T47D cells are sensitive to tamoxifen. Immunoprecipitation experiments revealed ER-c-Src-HER2 complex formation in BT474 cells but not in T47D cells. However, ER-c-Src-HER2 complex formation was detected after overexpressing HER2 in T47D cells and these cells were more resistant to tamoxifen. HER2 knockdown by siRNA in BT474 cells reduced ER-c-Src-HER2 complex formation and reversed tamoxifen resistance. ER-c-Src-HER2 complex formation was also disrupted and tamoxifen resistance was reversed in BT474 cells by the c-Src inhibitor PP2 and HER2 antibody trastuzumab. Nystatin, a lipid raft inhibitor, reduced ER-c-Src-HER2 complex formation and partially reversed tamoxifen resistance. ER-c-Src-HER2 complex formation was disrupted by overexpression of c-Cbl but not by the c-Cbl ubiquitin ligase mutant. In addition, c-Cbl could reverse tamoxifen resistance in BT474 cells, but the ubiquitin ligase mutant had no effect. The effect of c-Cbl was validated in BT474 tumor-bearing nude mice in vivo. Immunofluorescence also revealed ER-c-Src-HER2 complex formation was reduced in tumor tissues of nude mice with c-Cbl overexpression. Our results suggested that c-Cbl can reverse tamoxifen

  2. Chlorpheniramine Analogues Reverse Chloroquine Resistance in Plasmodium falciparum by Inhibiting PfCRT.

    Science.gov (United States)

    Deane, Karen J; Summers, Robert L; Lehane, Adele M; Martin, Rowena E; Barrow, Russell A

    2014-05-08

    The emergence and spread of malaria parasites that are resistant to chloroquine (CQ) has been a disaster for world health. The antihistamine chlorpheniramine (CP) partially resensitizes CQ-resistant (CQR) parasites to CQ but possesses little intrinsic antiplasmodial activity. Mutations in the parasite's CQ resistance transporter (PfCRT) confer resistance to CQ by enabling the protein to transport the drug away from its site of action, and it is thought that resistance-reversers such as CP exert their effect by blocking this CQ transport activity. Here, a series of new structural analogues and homologues of CP have been synthesized. We show that these compounds (along with other in vitro CQ resistance-reversers) inhibit the transport of CQ via a resistance-conferring form of PfCRT expressed in Xenopus laevis oocytes. Furthermore, the level of PfCRT-inhibition was found to correlate well with both the restoration of CQ accumulation and the level of CQ resensitization in CQR parasites.

  3. Reversal of chloroquine resistance in Plasmodium falciparum by CDR 87/209 and analogues.

    Science.gov (United States)

    Walter, R D; Seth, M; Bhaduri, A P

    1993-03-01

    The spreading of resistance towards chloroquine has diminished its value as a potent and safe drug in malaria endemic areas. Recent reports on the reversal of chloroquine resistance in the malaria parasite Plasmodium falciparum in vitro and in vivo by verapamil, desipramine and other Ca(2+)-channel blockers and antidepressants has initiated a strategy for chemotherapy by treatment with chloroquine in combination with a drug resistance modulator. Described here is a class of modulators of distinct structure which reverse chloroquine resistance in a different manner. Contrary to verapamil and desipramine, CDRI 87/209, the most potent compound of this new class and used as a chemical lead, did not restore chloroquine accumulation in the resistant parasites, thereby indicating that besides the proposed blockade of drug efflux other mechanisms are vulnerable targets for a chemotherapeutic approach towards drug resistance. Similar to the former modulators, CDRI 87/209 showed only weak intrinsic plasmodicidal activity and the increase of drug susceptibility was restricted to resistant plasmodia.

  4. 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

    c-Myc plays an essential role in proliferation, differentiation, and apoptosis. Because of its relevance to cancer, most studies have focused on the cellular consequences of c-Myc overexpression. Here, we address the role of physiological levels of c-Myc in drug-induced apoptosis. By using c-MYC ...... support a model in which doxorubicin simultaneously triggers multiple c-Myc-dependent apoptosis pathways....

  5. 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.

  6. MHD computation of feedback of resistive-shell instabilities in the reversed field pinch

    International Nuclear Information System (INIS)

    Zita, E.J.; Prager, S.C.

    1992-05-01

    MHD computation demonstrates that feedback can sustain reversal and reduce loop voltage in resistive-shell reversed field pinch (RFP) plasmas. Edge feedback on ∼2R/a tearing modes resonant near axis is found to restore plasma parameters to nearly their levels with a close-fitting conducting shell. When original dynamo modes are stabilized, neighboring tearing modes grow to maintain the RFP dynamo more efficiently. This suggests that experimentally observed limits on RFP pulselengths to the order of the shell time can be overcome by applying feedback to a few helical modes

  7. 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.

  8. Resistive instabilities in reversed shear discharges and wall stabilization on JT-60U

    International Nuclear Information System (INIS)

    Takeji, S.; Tokuda, S.; Fujita, T.; Suzuki, T.; Isayama, A.; Ide, S.; Ishii, Y.; Kamada, Y.; Koide, Y.; Matsumoto, T.; Oikawa, T.; Ozeki, T.; Sakamoto, Y.

    2001-01-01

    Resistive instabilities and wall stabilization of ideal low toroidal mode number, n, kink modes are investigated in JT-60U reversed shear discharges. Resistive interchange modes with n=1 are found to appear in reversed shear discharges with large pressure gradient at the normalized beta, β N , of about unity or even lower. The resistive interchange modes appear as intermittent burst-like magnetohydrodynamic (MHD) activities and higher n≤3 modes are observed occasionally in higher β N regime. No clear degradation of the plasma stored energy is observed by the resistive interchange modes themselves. It is also found that resistive interchange modes can lead to major collapse owing to a coupling with tearing modes at the outer mode rational surface over the minimum safety factor. Stability analysis revealed that stability parameter of tearing modes, Δ' , at the outer mode rational surface is affected by the free-boundary condition. The result is consistent with the experimental evidence that major collapse tends to occur when plasma edge safety factor, q*, is near integer values. Stabilization of ideal low n kink modes by the JT-60U wall is demonstrated. Magnetohydrodynamic perturbations that are attributed to resistive wall modes are observed followed by major collapse in wall-stabilized discharges. (author)

  9. Effects of the resistivity profile on the formation of a reversed configuration and single helicity states in compressible simulations of the reversed-field pinch

    International Nuclear Information System (INIS)

    Onofri, M.; Malara, F.

    2013-01-01

    Compressible magnetohydrodynamics simulations of the reversed-field pinch (RFP) are presented. Previous simulations of the RFP, including density and pressure evolution, showed that a stationary state with a reversed toroidal magnetic field could not be obtained, contrary to the results produced with numerical codes neglecting density and pressure dynamics. The simulations described in the present paper show that including density and pressure evolution, a stationary RFP configuration can be obtained if the resistivity has a radial profile steeply increasing close to the wall. Such resistivity profile is more realistic than a uniform resistivity, since the temperature at the wall is lower than in the plasma core

  10. 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.

  11. 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).

  12. Andrographolide reversed 5-FU resistance in human colorectal cancer by elevating BAX expression.

    Science.gov (United States)

    Wang, Weicheng; Guo, Wenjie; Li, Lele; Fu, Zan; Liu, Wen; Gao, Jian; Shu, Yongqian; Xu, Qiang; Sun, Yang; Gu, Yanhong

    2016-12-01

    5-FU is the first line therapy for colorectal cancer, however, treatment effect is often hampered by the development of drug resistance or toxicity at high doses. Andrographolide is a natural diterpenoid from Andrographis paniculata which has anti-bacterial, anti-antiviral and anti-inflammation activities. In the current study, we test the hypothesis that Andrographolide reverses 5-FU resistance in colorectal cancer and examine the underlying mechanism. In vitro and vivo studies indicated that Andrographolide treatment significantly re-sensitizes HCT116/5-FUR cells (HCT116 cells which are 5-FU resistant) to cytotoxicity of 5-FU. Mechanism analysis showed that Andrographolide/5-FU co-treatment elevated apoptosis level of HCT116/5-FUR cells with highly increased level of BAX. By using biotin-Andrographolide pull down and cellular thermal shift assay, we found out that Andrographolide can directly target to BAX. Andrographolide-BAX interaction prevented BAX degradation, enhancing mitochondria-mediated apoptosis thus reversed 5-FU resistance while BAX silence diminished this effect. Further, by analyzing patient samples who received 5-FU involved chemotherapy, we found that expression level of BAX is correlated with PFS. Our results here provide a novel combination treatment strategy, especially for patients with 5-FU-resistant tumors expressing low level of BAX. Meanwhile, we also proposed that BAX expression may be a predicted and prognosis marker of 5-FU involved chemotherapy. Copyright © 2016 Elsevier Inc. All rights reserved.

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

    Directory of Open Access Journals (Sweden)

    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.

  14. 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.

  15. β-Elemene Reverses Chemoresistance of Breast Cancer Cells by Reducing Resistance Transmission via Exosomes

    Directory of Open Access Journals (Sweden)

    Jun Zhang

    2015-07-01

    Full Text Available Background: Currently, exosomes that act as mediators of intercellular communication are being researched extensively. Our previous studies confirmed that these exosomes contain microRNAs (miRNAs that could alter chemo-susceptibility, which is partly attributed to the successful intercellular transfer of multidrug resistance (MDR-specific miRNAs. We also confirmed that β-elemene could influence MDR-related miRNA expression and regulate the expression of the target genes PTEN and Pgp, which may lead to the reversal of the chemoresistant breast cancer (BCA cells. We are the first to report these findings, and we propose the following logical hypothesis: β-elemene can mediate MDR-related miRNA expression in cells, thereby affecting the exosome contents, reducing chemoresistance transmission via exosomes, and reversing the drug resistance of breast cancer cells. Methods: MTT-cytotoxic, miRNA microarray, real-time quantitative PCR, Dual Luciferase Activity Assay, and Western blot analysis were performed to investigate the impact of β-elemene on the expression of chemoresistance specific miRNA and PTEN as well as Pgp in chemoresistant BCA exosomes. Results: Drug resistance can be reversed by β-elemene related to exosomes. There were 104 differentially expressed miRNAs in the exosomes of two chemoresistant BCA cells: adriacin (Adr - resistant MCF-7 cells (MCF-7/Adr and docetaxel (Doc - resistant MCF-7 cells (MCF-7/Doc that underwent treatment. Of these, 31 miRNAs were correlated with the constant changes in the MDR. The expression of miR-34a and miR-452 can lead to changes in the characteristics of two chemoresistant BCA exosomes: MCF-7/Adr exosomes (A/exo and MCF-7/Doc exosomes (D/exo. The PTEN expression affected by β-elemene was significantly increased, and the Pgp expression affected by β-elemene was significantly decreased in both cells and exosomes. β-elemene induced a significant increase in the apoptosis rate in both MCF-7/Doc and MCF-7

  16. 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.

  17. In vitro cross-resistance profile of nucleoside reverse transcriptase inhibitor (NRTI) BMS-986001 against known NRTI resistance mutations.

    Science.gov (United States)

    Li, Zhufang; Terry, Brian; Olds, William; Protack, Tricia; Deminie, Carol; Minassian, Beatrice; Nowicka-Sans, Beata; Sun, Yongnian; Dicker, Ira; Hwang, Carey; Lataillade, Max; Hanna, George J; Krystal, Mark

    2013-11-01

    BMS-986001 is a novel HIV nucleoside reverse transcriptase inhibitor (NRTI). To date, little is known about its resistance profile. In order to examine the cross-resistance profile of BMS-986001 to NRTI mutations, a replicating virus system was used to examine specific amino acid mutations known to confer resistance to various NRTIs. In addition, reverse transcriptases from 19 clinical isolates with various NRTI mutations were examined in the Monogram PhenoSense HIV assay. In the site-directed mutagenesis studies, a virus containing a K65R substitution exhibited a 0.4-fold change in 50% effective concentration (EC50) versus the wild type, while the majority of viruses with the Q151M constellation (without M184V) exhibited changes in EC50 versus wild type of 0.23- to 0.48-fold. Susceptibility to BMS-986001 was also maintained in an L74V-containing virus (0.7-fold change), while an M184V-only-containing virus induced a 2- to 3-fold decrease in susceptibility. Increasing numbers of thymidine analog mutation pattern 1 (TAM-1) pathway mutations correlated with decreases in susceptibility to BMS-986001, while viruses with TAM-2 pathway mutations exhibited a 5- to 8-fold decrease in susceptibility, regardless of the number of TAMs. A 22-fold decrease in susceptibility to BMS-986001 was observed in a site-directed mutant containing the T69 insertion complex. Common non-NRTI (NNRTI) mutations had little impact on susceptibility to BMS-986001. The results from the site-directed mutants correlated well with the more complicated genotypes found in NRTI-resistant clinical isolates. Data from clinical studies are needed to determine the clinically relevant resistance cutoff values for BMS-986001.

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

    Directory of Open Access Journals (Sweden)

    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

  19. Exosomes play an important role in the process of psoralen reverse multidrug resistance of breast cancer.

    Science.gov (United States)

    Wang, Xiaohong; Xu, Chengfeng; Hua, Yitong; Sun, Leitao; Cheng, Kai; Jia, Zhongming; Han, Yong; Dong, Jianli; Cui, Yuzhen; Yang, Zhenlin

    2016-12-01

    Release of exosomes have been shown to play critical roles in drug resistance by delivering cargo. Targeting the transfer of exosomes from resistant cells to sensitive cells may be an approach to overcome some cases of drug resistance. In this study, we investigated the potential role of exosomes in the process of psoralen reverse multidrug resistance of MCF-7/ADR cells. Exosomes were isolated by differential centrifugation of culture media from MCF-7/ADR cells (ADR/exo) and MCF-7 parental cells (S/exo). Exosomes were characterized by morphology, exosomal markers and size distribution. The ability of ADR/exo to transfer multidrug resistance was assessed by MTT and real-time quantitative PCR. The different formation and secretion of exosomes were detected by immunofluorescence and transmission electron microscopy. Then we performed comparative transcriptomic analysis using RNA-Seq technology and real-time quantitative PCR to better understand the gene expression regulation in exosmes formation and release after psoralen treatment. Our data showed that exosomes derived from MCF-7/ADR cells were able to promote active sequestration of drugs and could induce a drug resistance phenotype by transferring drug-resistance-related gene MDR-1 and P-glycoprotein protein. Psoralen could reduce the formation and secretion of exosomes to overcome drug resistance. There were 21 differentially expressed genes. Gene ontology (GO) pathway analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that the most significantly expressed genes were linked to PPAR and P53 signaling pathways which were related to exosomes formation, secretion and cargo sorting. Psoralen can affect the exosomes and induce the reduction of resistance transmission via exosomes might through PPAR and P53 signaling pathways, which might provide a novel strategy for breast cancer resistance to chemotherapy in the future.

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

    Science.gov (United States)

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

    2012-08-15

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

  1. Synthesis, Antiproliferative, and Multidrug Resistance Reversal Activities of Heterocyclic α,β-Unsaturated Carbonyl Compounds.

    Science.gov (United States)

    Sun, Ju-Feng; Hou, Gui-Ge; Zhao, Feng; Cong, Wei; Li, Hong-Juan; Liu, Wen-Shuai; Wang, Chunhua

    2016-10-01

    A series of heterocyclic α,β-unsaturated carbonyl compounds (1a-1d, 2a-2d, 3a-3d, 4a-3d, and 5a-5d) with 1,5-diaryl-3-oxo-1,4-pentadienyl pharmacophore were synthesized for the development of anticancer and multidrug resistance reverting agents. The antiproliferative activities were tested against nine human cancer cell lines. Approximately 73% of the IC50 values were below 5 μm, while 35% of these figures were submicromolar, and compounds 3a-3d with 4-trifluoro methyl in the arylidene benzene rings were the most potent, since their IC50 values are between 0.06 and 3.09 μm against all cancer cell lines employed. Meanwhile, their multidrug resistance reversal properties and cellular uptake were further examined. The data displayed that all of these compounds could reverse multidrug resistance, particularly, compounds 3a and 4a demonstrated both potent multidrug resistance reverting properties and strong antiproliferative activities, which can be taken as leading molecules for further research of dual effect agents in tumor chemotherapy. © 2016 John Wiley & Sons A/S.

  2. 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.

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

    International Nuclear Information System (INIS)

    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

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

    Directory of Open Access Journals (Sweden)

    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.

  5. Reversible Resistance Switching Effect in Amorphous Ge1Sb4Te7 Thin Films without Phase Transformation

    International Nuclear Information System (INIS)

    Hua-Jun, Sun; Li-Song, Hou; Yi-Qun, Wu; Xiao-Dong, Tang

    2009-01-01

    We demonstrate a reversible resistance switching effect that does not rely on amorphous-crystalline phase transformation in a nanoscale capacitor-like cell using Ge 1 Sb 4 Te 7 films as the working material. The polarity and amplitude of the applied electric voltage switches the cell resistance between low- and high-resistance states, as revealed in the current-voltage characteristics of the film by conductive atomic force microscopy (CAFM). This reversible SET/RESET switching effect is induced by voltage pulses and their polarity. The change of electrical resistance due to the switching effect is approximately two orders of magnitude

  6. [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.

  7. 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.

  8. Reversible voltage dependent transition of abnormal and normal bipolar resistive switching.

    Science.gov (United States)

    Wang, Guangyu; Li, Chen; Chen, Yan; Xia, Yidong; Wu, Di; Xu, Qingyu

    2016-11-14

    Clear understanding the mechanism of resistive switching is the important prerequisite for the realization of high performance nonvolatile resistive random access memory. In this paper, binary metal oxide MoO x layer sandwiched by ITO and Pt electrodes was taken as a model system, reversible transition of abnormal and normal bipolar resistive switching (BRS) in dependence on the maximum voltage was observed. At room temperature, below a critical maximum voltage of 2.6 V, butterfly shaped I-V curves of abnormal BRS has been observed with low resistance state (LRS) to high resistance state (HRS) transition in both polarities and always LRS at zero field. Above 2.6 V, normal BRS was observed, and HRS to LRS transition happened with increasing negative voltage applied. Temperature dependent I-V measurements showed that the critical maximum voltage increased with decreasing temperature, suggesting the thermal activated motion of oxygen vacancies. Abnormal BRS has been explained by the partial compensation of electric field from the induced dipoles opposite to the applied voltage, which has been demonstrated by the clear amplitude-voltage and phase-voltage hysteresis loops observed by piezoelectric force microscopy. The normal BRS was due to the barrier modification at Pt/MoO x interface by the accumulation and depletion of oxygen vacancies.

  9. Performance of PCR-reverse blot hybridization assay for detection of rifampicin-resistant Mycobacterium leprae.

    Science.gov (United States)

    Wang, Hye-young; Kim, Hyunjung; Kim, Yeun; Bang, Hyeeun; Kim, Jong-Pill; Hwang, Joo Hwan; Cho, Sang-Nae; Kim, Tae Ue; Lee, Hyeyoung

    2015-10-01

    Drug resistance in Mycobacterium leprae is a significant problem in countries where leprosy is endemic. A sensitive, specific, and high-throughput reverse blot hybridization assay (REBA) for the detection of genotypic resistance to rifampicin (RIF) was designed and evaluated. It has been shown that resistance to RIF in M. leprae involves mutations in the rpoB gene encoding the -subunit of the RNA polymerase. The PCR-REBA simultaneously detects both 6 wild-type regions and 5 different mutations (507 AGC, 513 GTG, 516 TAT, 531 ATG, and 531 TTC) including the most prevalent mutations at positions 507 and 531. Thirty-one clinical isolates provided by Korea Institute of Hansen-s Disease were analyzed by PCR-REBA with RIF resistance of rpoB gene. As a result, missense mutations at codons 507 AGC and 531 ATG with 2-nucleotide substitutions were found in one sample, and a missense mutation at codon 516 TAT and ΔWT6 (deletion of 530-534) was found in another sample. These cases were confirmed by DNA sequence analysis. This rapid, simple, and highly sensitive assay provides a practical alternative to sequencing for genotypic evaluation of RIF resistance in M. leprae.

  10. The emerging profile of cross-resistance among the nonnucleoside HIV-1 reverse transcriptase inhibitors.

    Science.gov (United States)

    Sluis-Cremer, Nicolas

    2014-07-31

    Nonnucleoside reverse transcriptase inhibitors (NNRTIs) are widely used to treat HIV-1-infected individuals; indeed most first-line antiretroviral therapies typically include one NNRTI in combination with two nucleoside analogs. In 2008, the next-generation NNRTI etravirine was approved for the treatment of HIV-infected antiretroviral therapy-experienced individuals, including those with prior NNRTI exposure. NNRTIs are also increasingly being included in strategies to prevent HIV-1 infection. For example: (1) nevirapine is used to prevent mother-to-child transmission; (2) the ASPIRE (MTN 020) study will test whether a vaginal ring containing dapivirine can prevent HIV-1 infection in women; (3) a microbicide gel formulation containing the urea-PETT derivative MIV-150 is in a phase I study to evaluate safety, pharmacokinetics, pharmacodynamics and acceptability; and (4) a long acting rilpivirine formulation is under-development for pre-exposure prophylaxis. Given their widespread use, particularly in resource-limited settings, as well as their low genetic barriers to resistance, there are concerns about overlapping resistance between the different NNRTIs. Consequently, a better understanding of the resistance and cross-resistance profiles among the NNRTI class is important for predicting response to treatment, and surveillance of transmitted drug-resistance.

  11. Review The Emerging Profile of Cross-Resistance among the Nonnucleoside HIV-1 Reverse Transcriptase Inhibitors

    Directory of Open Access Journals (Sweden)

    Nicolas Sluis-Cremer

    2014-07-01

    Full Text Available Nonnucleoside reverse transcriptase inhibitors (NNRTIs are widely used to treat HIV-1-infected individuals; indeed most first-line antiretroviral therapies typically include one NNRTI in combination with two nucleoside analogs. In 2008, the next-generation NNRTI etravirine was approved for the treatment of HIV-infected antiretroviral therapy-experienced individuals, including those with prior NNRTI exposure. NNRTIs are also increasingly being included in strategies to prevent HIV-1 infection. For example: (1 nevirapine is used to prevent mother-to-child transmission; (2 the ASPIRE (MTN 020 study will test whether a vaginal ring containing dapivirine can prevent HIV-1 infection in women; (3 a microbicide gel formulation containing the urea-PETT derivative MIV-150 is in a phase I study to evaluate safety, pharmacokinetics, pharmacodynamics and acceptability; and (4 a long acting rilpivirine formulation is under-development for pre-exposure prophylaxis. Given their widespread use, particularly in resource-limited settings, as well as their low genetic barriers to resistance, there are concerns about overlapping resistance between the different NNRTIs. Consequently, a better understanding of the resistance and cross-resistance profiles among the NNRTI class is important for predicting response to treatment, and surveillance of transmitted drug-resistance.

  12. MDM2 Antagonist Nutlin-3a Reverses Mitoxantrone Resistance by Inhibiting Breast Cancer Resistance Protein Mediated Drug Transport

    Science.gov (United States)

    Zhang, Fan; Throm, Stacy L.; Murley, Laura L.; Miller, Laura A.; Zatechka, D. Steven; Guy, R. Kiplin; Kennedy, Rachel; Stewart, Clinton F.

    2011-01-01

    Breast cancer resistance protein (BCRP; ABCG2), a clinical marker for identifying the side population (SP) cancer stem cell subgroup, affects intestinal absorption, brain penetration, hepatobiliary excretion, and multidrug resistance of many anti-cancer drugs. Nutlin-3a is currently under pre-clinical investigation in a variety of solid tumor and leukemia models as a p53 reactivation agent, and has been recently demonstrated to also have p53 independent actions in cancer cells. In the present study, we first report that nutlin-3a can inhibit the efflux function of BCRP. We observed that although the nutlin-3a IC50 did not differ between BCRP over-expressing and vector control cells, nutlin-3a treatment significantly potentiated the cells to treatment with the BCRP substrate mitoxantrone. Combination index calculations suggested synergism between nutlin-3a and mitoxantrone in cell lines over-expressing BCRP. Upon further investigation, it was confirmed that nutlin-3a increased the intracellular accumulation of BCRP substrates such as mitoxantrone and Hoechst 33342 in cells expressing functional BCRP without altering the expression level or localization of BCRP. Interestingly, nutlin-3b, considered virtually “inactive” in disrupting the MDM2/p53 interaction, reversed Hoechst 33342 efflux with the same potency as nutlin-3a. Intracellular accumulation and bi-directional transport studies using MDCKII cells suggested that nutlin-3a is not a substrate of BCRP. Additionally, an ATPase assay using Sf9 insect cell membranes over-expressing wild-type BCRP indicated that nutlin-3a inhibits BCRP ATPase activity in a dose-dependent fashion. In conclusion, our studies demonstrate that nutlin-3a inhibits BCRP efflux function, which consequently reverses BCRP-related drug resistance. PMID:21459080

  13. Study of tea polyphenol as a reversal agent for carcinoma cell lines' multidrug resistance (study of TP as a MDR reversal agent)

    International Nuclear Information System (INIS)

    Zhu Aizhi; Wang Xiangyun; Guo Zhenquan

    2001-01-01

    The aim of this study was to examine MDR1 expression product P-glycoprotein (Pgp) and study the effect and mechanism of tea polyphenol (TP) in reversion of multidrug resistance (MDR) in carcinoma cell lines. Immunocytochemical method was used for qualitative detection of Pgp. A comparative study of cytotoxicity and multidrug resistance reversion effect was made by MTT assay for tea polyphenol and quinidine in MCF-7 and MCF-7/Adr cell lines. The multidrug resistance reversion effect and mechanism were studied by measuring the uptake of 99m Tc-tetrofosmin in the carcinoma cell lines. (1) The Pgp overexpression in MCF-7/Adr cells was found to be strong positive, while the Pgp expression of MCF-7 was negative. (2) Although both tea polyphenol and quinidine could not remarkably change the toxicity of adriamycin to MCF-7, they could improve the sensitivity of MCF-7/Adr to adriamycin. The reversion index of tea polyphenol and quinidine was 3 and 10 respectively. (3) The cellular uptake of 99m Tc-tetrofosmin was remarkably lower in MCF-7/Adr than in MCF-7. The uptake of 99m Tc-tetrofosmin in MCF-7/Adr exhibited a 4, 13, 16 fold increase in the presence of 200, 400 and 500 μg/ml of tea polyphenol respectively. The uptake of 99m Tc-tetrofosmin in MCF-7/Adr exhibited only a 4-fold increase in the presence of 200 μM of quinidine. Immunocytochemistry can detect P-glycoprotein expression level qualitatively. Tea polyphenol is not only an anti-tumor agent, but also a multidrug resistant modulator similar to quinidine. The multidrug resistance reversion mechanism of tea polyphenol seems to be its inhibition of the activity of P-glycoprotein. Tea polyphenol has the advantage of very low toxicity in tumor treatment

  14. Knockdown of dual specificity phosphatase 4 enhances the chemosensitivity of MCF-7 and MCF-7/ADR breast cancer cells to doxorubicin

    International Nuclear Information System (INIS)

    Liu, Yu; Du, Feiya; Chen, Wei; Yao, Minya; Lv, Kezhen; Fu, Peifen

    2013-01-01

    Background: Breast cancer is the major cause of cancer-related deaths in females world-wide. Doxorubicin-based therapy has limited efficacy in breast cancer due to drug resistance, which has been shown to be associated with the epithelial-to-mesenchymal transition (EMT). However, the molecular mechanisms linking the EMT and drug resistance in breast cancer cells remain unclear. Dual specificity phosphatase 4 (DUSP4), a member of the dual specificity phosphatase family, is associated with cellular proliferation and differentiation; however, its role in breast cancer progression is controversial. Methods: We used cell viability assays, Western blotting and immunofluorescent staining, combined with siRNA interference, to evaluate chemoresistance and the EMT in MCF-7 and adriamycin-resistant MCF-7/ADR breast cancer cells, and investigate the underlying mechanisms. Results: Knockdown of DUSP4 significantly increased the chemosensitivity of MCF-7 and MCF-7/ADR breast cancer cells to doxorubicin, and MCF-7/ADR cells which expressed high levels of DUSP4 had a mesenchymal phenotype. Furthermore, knockdown of DUSP4 reversed the EMT in MCF-7/ADR cells, as demonstrated by upregulation of epithelial biomarkers and downregulation of mesenchymal biomarkers, and also increased the chemosensitivity of MCF-7/ADR cells to doxorubicin. Conclusions: DUSP4 might represent a potential drug target for inhibiting drug resistance and regulating the process of the EMT during the treatment of breast cancer. - Highlights: • We used different technologies to prove our conclusion. • DUSP4 knockdown increased doxorubicin chemosensitivity in breast cancer cells. • DUSP4 is a potential target for combating drug resistance in breast cancer. • DUSP4 is a potential target for regulating the EMT in breast cancer

  15. Reversed-field pinch experiments in EXTRAP T2R with a resistive shell boundary

    International Nuclear Information System (INIS)

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

    2003-01-01

    The EXTRAP T2R reversed-field pinch has a resistive shell with a magnetic penetration time of 6 ms. This time is intermediate between the dynamo/relaxation cycle time scale (<2ms) and the pulse length (∼20ms). The resonant tearing modes do not wall-lock. They rotate with angular phase velocities in the range of 20 to 600 krad/s. As a result of the rotation the radial component of the perturbations at the shell from the resonant modes is suppressed. Non-resonant (resistive-wall) kink modes are unstable and their linear growth rates have been measured. The measured growth rates follow the trend expected from theoretical estimates for a range of equilibrium parameters. Furthermore, when the resonant modes are rotating, the loop voltage and confinement parameters have values comparable to those of a conducting shell RFP. The poloidal beta is around 10% for a range of current and density. (author)

  16. Comparison between the boundary layer and global resistivity methods for tearing modes in reversed field configurations

    International Nuclear Information System (INIS)

    Santiago, M.A.M.

    1987-01-01

    A review of the problem of growth rate calculations for tearing modes in field reversed Θ-pinches is presented. Its shown that in the several experimental data, the methods used for analysing the plasma with a global finite resistivity has a better quantitative agreement than the boundary layer analysis. A comparative study taking into account the m = 1 resistive kindmode and the m = 2 mode, which is more dangerous for the survey of rotational instabilities of the plasma column is done. It can see that the imaginary component of the eigenfrequency, which determinates the growth rate, has a good agreement with the experimental data and the real component is different from the rotational frequency as it has been measured in some experiments. (author) [pt

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

    International Nuclear Information System (INIS)

    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

  18. Phorate can reverse P450 metabolism-based herbicide resistance in Lolium rigidum.

    Science.gov (United States)

    Busi, Roberto; Gaines, Todd Adam; Powles, Stephen

    2017-02-01

    Organophosphate insecticides can inhibit specific cytochrome P450 enzymes involved in metabolic herbicide resistance mechanisms, leading to synergistic interactions between the insecticide and the herbicide. In this study we report synergistic versus antagonistic interactions between the organophosphate insecticide phorate and five different herbicides observed in a population of multiple herbicide-resistant Lolium rigidum. Phorate synergised with three different herbicide modes of action, enhancing the activity of the ALS inhibitor chlorsulfuron (60% LD 50 reduction), the VLCFAE inhibitor pyroxasulfone (45% LD 50 reduction) and the mitosis inhibitor trifluralin (70% LD 50 reduction). Conversely, phorate antagonised the two thiocarbamate herbicides prosulfocarb and triallate with a 12-fold LD 50 increase. We report the selective reversal of P450-mediated metabolic multiple resistance to chlorsulfuron and trifluralin in the grass weed L. rigidum by synergistic interaction with the insecticide phorate, and discuss the putative mechanistic basis. This research should encourage diversity in herbicide use patterns for weed control as part of a long-term integrated management effort to reduce the risk of selection of metabolism-based multiple herbicide resistance in L. rigidum. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  19. Increased expression of bHLH transcription factor E2A (TCF3) in prostate cancer promotes proliferation and confers resistance to doxorubicin induced apoptosis

    International Nuclear Information System (INIS)

    Patel, Divya; Chaudhary, Jaideep

    2012-01-01

    Highlights: ► E2A, considered as a tumor suppressor is highly expressed in prostate cancer. ► Silencing of E2A attenuates cell proliferation and promotes apoptosis. ► E2A regulates c-myc, Id1, Id3 and CDKN1A expression. ► Loss of E2A promotes doxorubicin dependent apoptosis in prostate cancer cells. ► Results suggest that E2A acts as a tumor promoter at least in prostate cancer. -- Abstract: E2A (TCF3) is a multifunctional basic helix loop helix (bHLH), transcription factor. E2A regulates transcription of target genes by homo- or heterodimerization with cell specific bHLH proteins. In general, E2A promotes cell differentiation, acts as a negative regulator of cell proliferation in normal cells and cancer cell lines and is required for normal B-cell development. Given the diverse biological pathways regulated/influenced by E2A little is known about its expression in cancer. In this study we investigated the expression of E2A in prostate cancer. Unexpectedly, E2A immuno-histochemistry demonstrated increased E2A expression in prostate cancer as compared to normal prostate. Silencing of E2A in prostate cancer cells DU145 and PC3 led to a significant reduction in proliferation due to G1 arrest that was in part mediated by increased CDKN1A(p21) and decreased Id1, Id3 and c-myc. E2A silencing in prostate cancer cell lines also resulted in increased apoptosis due to increased mitochondrial permeability and caspase 3/7 activation. Moreover, silencing of E2A increased sensitivity to doxorubicin induced apoptosis. Based on our results, we propose that E2A could be an upstream regulator of Id1 and c-Myc which are highly expressed in prostate cancer. These results for the first time demonstrate that E2A could in fact acts as a tumor promoter at least in prostate cancer.

  20. 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.

  1. Effect of reverse cyclic loading on the fracture resistance curve in C(T) specimen

    International Nuclear Information System (INIS)

    Sung Seok, C.; Jin Kim, Y.; Il Weon, J.

    1999-01-01

    Fracture resistance (J-R) curves, which are used for elastic-plastic fracture mechanics analyses, are known to be dependent on the cyclic loading history. The objective of this paper is to investigate the effect of reverse cyclic loading on the J-R curves in C(T) specimens. The effect of two parameters was observed on the J-R curves during the reverse cyclic loading. One was the minimum-to-maximum load ratio (R) and the other was the incremental plastic displacement (δ cycle /δ i ), which is related to the amount of crack growth that occurs in a cycle. Fracture resistance tests on C(T) specimens with varying the load ratio and the incremental plastic displacement were performed, and the test results showed that the J-R curves were decreased with decreasing the load ratio and decreasing the incremental plastic displacement. Direct current potential drop (DCPD) method was used for the detection of crack initiation and crack growth in typical laboratory J-R tests. The values of crack initiation J-integral (J I ) and crack initiation displacement (δ i ) were also obtained by using the DCPD method. (orig.)

  2. Effect of reverse cyclic loading on the fracture resistance curve of nuclear piping material

    International Nuclear Information System (INIS)

    Weon, Jong Il; Seok, Chang Sung

    1999-01-01

    Fracture resistance (J-R) curves, which are used for the elastic-plastic fracture mechanics analyses, are known to be dependent on the cyclic loading history. The objective of this paper is to study the effect of reverse cyclic loading on J-R curves in CT specimens. The effect of two parameters was observed on the J-R curves during the reverse cyclic loading. One was the minimum-to-maximum load ratio (R) and the other was the incremental plastic displacement (δ cycle /δ i ), which is related to the amount of crack growth that occurs in a cycle. Fracture resistance test on CT specimens with varying load ratio and incremental plastic displacement were performed. For the SA 516 Gr. 70 steel, the results showed that the J-R curves were decreased with decreasing the load ratio and the incremental plastic displacement. When the load ratio was set to -1, the results of the J-R curves and the J i value were about 40-50 percent of those for the monotonic loading condition. Also on condition that the incremental plastic displacement reached 1/40, the J-R curves and the J i value were about 50-60 percent of those for the incremental plastic displacement of 1/10

  3. The structure of FIV reverse transcriptase and its implications for non-nucleoside inhibitor resistance.

    Directory of Open Access Journals (Sweden)

    Meytal Galilee

    2018-01-01

    Full Text Available Reverse transcriptase (RT is the target for the majority of anti-HIV-1 drugs. As with all anti-AIDS treatments, continued success of RT inhibitors is persistently disrupted by the occurrence of resistance mutations. To explore latent resistance mechanisms potentially accessible to therapeutically challenged HIV-1 viruses, we examined RT from the related feline immunodeficiency virus (FIV. FIV closely parallels HIV-1 in its replication and pathogenicity, however, is resistant to all non-nucleoside inhibitors (NNRTI. The intrinsic resistance of FIV RT is particularly interesting since FIV harbors the Y181 and Y188 sensitivity residues absent in both HIV-2 and SIV. Unlike RT from HIV-2 or SIV, previous efforts have failed to make FIV RT susceptible to NNRTIs concluding that the structure or flexibility of the feline enzyme must be profoundly different. We report the first crystal structure of FIV RT and, being the first structure of an RT from a non-primate lentivirus, enrich the structural and species repertoires available for RT. The structure demonstrates that while the NNRTI binding pocket is conserved, minor subtleties at the entryway can render the FIV RT pocket more restricted and unfavorable for effective NNRTI binding. Measuring NNRTI binding affinity to FIV RT shows that the "closed" pocket configuration inhibits NNRTI binding. Mutating the loop residues rimming the entryway of FIV RT pocket allows for NNRTI binding, however, it does not confer sensitivity to these inhibitors. This reveals a further layer of resistance caused by inherent FIV RT variances that could have enhanced the dissociation of bound inhibitors, or, perhaps, modulated protein plasticity to overcome inhibitory effects of bound NNRTIs. The more "closed" conformation of FIV RT pocket can provide a template for the development of innovative drugs that could unlock the constrained pocket, and the resilient mutant version of the enzyme can offer a fresh model for the study

  4. Poly-L-arginine: Enhancing Cytotoxicity and Cellular Uptake of Doxorubicin and Necrotic Cell Death.

    Science.gov (United States)

    Movafegh, Bahareh; Jalal, Razieh; Mohammadi, Zobeideh; Aldaghi, Seyyede Araste

    2018-04-11

    Cell resistance to doxorubicin and its toxicity to healthy tissue reduce its efficiency. The use of cell penetrating peptides as drug delivery system along with doxorubicin is a strategy to reduce its side effects. In this study, the influence of poly-L-arginine on doxorubicin cytotoxicity, its cellular uptake and doxorubicin-induced apoptosis on human prostate cancer DU145 cells are assessed. The cytotoxicity of doxorubicin and poly-L-arginine, alone and in combination, in DU145 cells was evaluated at different exposure times using MTT assay. The influence of poly-L-arginine on doxorubicin delivery into cells was evaluated by fluorescence microscopy and ultraviolet spectroscopy. DAPI and ethidium bromide-acridine orange stainings, flow cytometry using annexin V/propidium iodide, western blot analysis with anti-p21 antibody and caspase-3 activity were used to examine the influence of poly-L-arginine on doxorubicin-induced cell death. Poly-L-arginine had no cytotoxicity at low concentrations and short exposure times. Poly-L-arginine increased the cytotoxic effect of doxorubicin in DU145 cells in a time-dependent manner. But no significant reduction was found in HFF cell viability. Poly-L-arginine seems to facilitate doxorubicin uptake and increase its intracellular concentration. 24 h combined treatment of cells with doxorubicin (0.5 μM) and poly-L-arginine (1 μg ml-1) caused a small increase in doxorubicin-induced apoptosis and significant elevated necrosis in DU145 cells as compared to each agent alone. Conlusion: Our results indicate that poly-L-arginine at lowest and highest concentrations act as proliferation-inducing and antiproliferative agents, respectively. Between these concentrations, poly-L-arginine increases the cellular uptake of doxorubicin and its cytotoxicity through induction of necrosis. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  5. 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.

  6. Reversed-field pinch experiments in EXTRAP T2R with a resistive shell boundary

    International Nuclear Information System (INIS)

    Drake, J.R.

    2002-01-01

    The EXTRAP T2R reversed-field pinch is operated with a resistive shell with a magnetic penetration time of 6 ms. This time is intermediate between the dynamo/relaxation cycle time scale (<1 ms) and the pulse length (= 20 ms). The internally-resonant tearing modes do not wall lock and exhibit natural rotation with velocities in the range of 20 to 600 krad/s. Under these conditions the radial component of the tearing mode perturbation at the shell is suppressed. Therefore the linear growth rates of the unstable, non-resonant, ideal (resistive-wall) kink modes can be observed even at very low amplitudes (0.01% of the equilibrium field). Both internally-non-resonant and externally non-resonant RW mode types are observed. The growth rates have been measured for a range of equilibrium current profile parameters and are compared with theoretical estimates. Previous observations and simulations for the resistive-shell RFP have shown an increased loop voltage associated with altered dynamo dynamics. When the tearing modes are rotating, the loop voltage and confinement parameters have values comparable to those of a conducting-shell RFP. (author)

  7. Reversing bacterial resistance to antibiotics by phage-mediated delivery of dominant sensitive genes.

    Science.gov (United States)

    Edgar, Rotem; Friedman, Nir; Molshanski-Mor, Shahar; Qimron, Udi

    2012-02-01

    Pathogen resistance to antibiotics is a rapidly growing problem, leading to an urgent need for novel antimicrobial agents. Unfortunately, development of new antibiotics faces numerous obstacles, and a method that resensitizes pathogens to approved antibiotics therefore holds key advantages. We present a proof of principle for a system that restores antibiotic efficiency by reversing pathogen resistance. This system uses temperate phages to introduce, by lysogenization, the genes rpsL and gyrA conferring sensitivity in a dominant fashion to two antibiotics, streptomycin and nalidixic acid, respectively. Unique selective pressure is generated to enrich for bacteria that harbor the phages carrying the sensitizing constructs. This selection pressure is based on a toxic compound, tellurite, and therefore does not forfeit any antibiotic for the sensitization procedure. We further demonstrate a possible way of reducing undesirable recombination events by synthesizing dominant sensitive genes with major barriers to homologous recombination. Such synthesis does not significantly reduce the gene's sensitization ability. Unlike conventional bacteriophage therapy, the system does not rely on the phage's ability to kill pathogens in the infected host, but instead, on its ability to deliver genetic constructs into the bacteria and thus render them sensitive to antibiotics prior to host infection. We believe that transfer of the sensitizing cassette by the constructed phage will significantly enrich for antibiotic-treatable pathogens on hospital surfaces. Broad usage of the proposed system, in contrast to antibiotics and phage therapy, will potentially change the nature of nosocomial infections toward being more susceptible to antibiotics rather than more resistant.

  8. Low intensity ultrasound promotes the sensitivity of rat brain glioma to Doxorubicin by down-regulating the expressions of p-glucoprotein and multidrug resistance protein 1 in vitro and in vivo.

    Directory of Open Access Journals (Sweden)

    Zhen Zhang

    Full Text Available The overall prognosis for malignant glioma is extremely poor, and treatment options are limited in part because of multidrug resistant proteins. Our previous findings suggest low intensity ultrasound (LIUS can induce apoptosis of glioma cells. Given this finding, we were interested in determining if LIUS could help treat glioma by inhibiting multidrug resistant proteins, and if so, which pathways are involved. In this study, the toxicity sensitivity and multidrug resistance proteins of glioma induced by LIUS were investigated using CCK-8, immunohistochemistry, immunofluorency, and RT-PCR in tissue samples and cultured cells. LIUS inhibited increase of C6 cells in an intensity- and time-dependent manner. The toxicity sensitivity of C6 cells increased significantly after LIUS sonication (intensity of 142.0 mW/cm(2 or Doxorubicin (DOX at different concentration, particularly by the combination of LIUS sonication and DOX. The expressions of P-gp and MRP1 decreased significantly post-sonication at intensity of 142.0 mW/cm(2 both in vitro and in vivo. The expressions of p110 delta (PI3K, NF-κB-p65, Akt/PKB, and p-Akt/PKB were downregulated by LIUS sonication and DOX treatment separately or in combination at the same parameters in rat glioma. These results indicate that LIUS could increase the toxicity sensitivity of glioma by down-regulating the expressions of P-gp and MRP1, which might be mediated by the PI3K/Akt/NF-κB pathway.

  9. Reversible Dissolution of Microdomains in Detergent-Resistant Membranes at Physiological Temperature.

    Directory of Open Access Journals (Sweden)

    Andrea Cremona

    Full Text Available The formation of lipid microdomains ("rafts" is presumed to play an important role in various cellular functions, but their nature remains controversial. Here we report on microdomain formation in isolated, detergent-resistant membranes from MDA-MB-231 human breast cancer cells, studied by atomic force microscopy (AFM. Whereas microdomains were readily observed at room temperature, they shrunk in size and mostly disappeared at higher temperatures. This shrinking in microdomain size was accompanied by a gradual reduction of the height difference between the microdomains and the surrounding membrane, consistent with the behaviour expected for lipids that are laterally segregated in liquid ordered and liquid disordered domains. Immunolabeling experiments demonstrated that the microdomains contained flotillin-1, a protein associated with lipid rafts. The microdomains reversibly dissolved and reappeared, respectively, on heating to and cooling below temperatures around 37 °C, which is indicative of radical changes in local membrane order close to physiological temperature.

  10. Reversible Dissolution of Microdomains in Detergent-Resistant Membranes at Physiological Temperature

    Science.gov (United States)

    Cremona, Andrea; Orsini, Francesco; Corsetto, Paola A.; Hoogenboom, Bart W.; Rizzo, Angela M.

    2015-01-01

    The formation of lipid microdomains (“rafts”) is presumed to play an important role in various cellular functions, but their nature remains controversial. Here we report on microdomain formation in isolated, detergent-resistant membranes from MDA-MB-231 human breast cancer cells, studied by atomic force microscopy (AFM). Whereas microdomains were readily observed at room temperature, they shrunk in size and mostly disappeared at higher temperatures. This shrinking in microdomain size was accompanied by a gradual reduction of the height difference between the microdomains and the surrounding membrane, consistent with the behaviour expected for lipids that are laterally segregated in liquid ordered and liquid disordered domains. Immunolabeling experiments demonstrated that the microdomains contained flotillin-1, a protein associated with lipid rafts. The microdomains reversibly dissolved and reappeared, respectively, on heating to and cooling below temperatures around 37°C, which is indicative of radical changes in local membrane order close to physiological temperature. PMID:26147107

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

    International Nuclear Information System (INIS)

    Yadikin, Dmitriy

    2006-03-01

    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 wall characterized by a wall field diffusion time, cannot stabilize the ideal MHD modes unless they rotate with Alfvenic velocity, which is usually not the case. With a resistive wall, the ideal modes are converted into resistive wall modes (RWM) with growth rates comparable to the inverse wall time. Resistive wall modes have been studied in the EXTRAP T2R thin shell RFP device. Growth rates have been measured and found in agreement with linear MHD stability calculations. An advanced system for active control has been developed and installed on the EXTRAP T2R device. The system includes an array of 128 active saddle coils, fully covering the torus surface. Experiments on EXTRAP T2R have for the first time demonstrated simultaneous active suppression of multiple independent RWMs. In experiments with a partial array, coupling of different modes due to the limited number of feedback coils has been observed, in agreement with theory. Different feedback strategies, such as the intelligent shell, the rotating shell, and mode control have been studied. Further, feedback operation with different types of magnetic field sensors, measuring either the radial or the toroidal field components have been compared

  12. 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.

  13. Emodin reverses leukemia multidrug resistance by competitive inhibition and downregulation of P-glycoprotein.

    Directory of Open Access Journals (Sweden)

    Hongping Min

    Full Text Available Development of multidrug resistance (MDR is a continuous clinical challenge partially due to the overexpression of P-glycoprotein (P-gp for chronic myelogenous leukemia (CML patients. Herein, we evaluated the inhibitory potency of emodin, a natural anthraquinone derivative isolated from Rheum palmatum L, on P-gp in P-gp positive K562/ADM cells. Competition experiments combined with molecular docking analysis were utilized to investigate the binding modes between emodin and binding sites of P-gp. Emodin reversed adriamycin resistance in K562/ADM cells accompanied with the decrease of P-gp protein expression, further increasing the uptake of rhodamine123 in both K562/ADM and Caco-2 cells, indicating the inhibition of P-gp efflux function. Moreover, when incubated with emodin under different conditions where P-gp was inhibited, K562/ADM cells displayed increasing intracellular uptake of emodin, suggesting that emodin may be the potential substrate of P-gp. Importantly, rhodamine 123 could increase the Kintrinsic (Ki value of emodin linearly, whereas, verapamil could not, implying that emodin competitively bound to the R site of P-gp and noncompetition existed between emodin and verapamil at the M site, in a good accordance with the results of molecular docking that emodin bound to the R site of P-gp with higher affinity. Based on our results, we suggest that emodin might be used to modulate P-gp function and expression.

  14. Chlorine-Resistant Polyamide Reverse Osmosis Membrane with Monitorable and Regenerative Sacrificial Layers.

    Science.gov (United States)

    Huang, Hai; Lin, Saisai; Zhang, Lin; Hou, Li'an

    2017-03-22

    Improving chlorine stability is a high priority for aromatic polyamide (PA) reverse osmosis (RO) membranes especially in long-term desalination. In this Research Article, PA RO membranes of sustainable chlorine resistance was synthesized. Glycylglycine (Gly) was grafted onto the membrane surface as a regenerative chlorine sacrificial layer, and the zeta-potential was used to monitor the membrane performance and to conduct timely regeneration operations for chlorinated Gly. The Gly-grafted PA membrane exhibited ameliorative chlorine resistance in which the N-H moiety of glycylglycine served as sacrificial pendants against chlorine attacks. Cyclic chlorination experiments, combined with FT-IR and XPS analysis, were carried out to characterize the membrane. Results indicated that the resulting N-halamines could be fast regenerated by a simple alkaline reduction step (pH 10). A synchronous relationship between the zeta-potential and the chlorination extent of the sacrificial layer was observed. This indicated that the zeta-potential can be used as an on-site sensor to conduct a timely regeneration operation. The intrinsic mechanism of the surface sacrificial process was also studied.

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

    International Nuclear Information System (INIS)

    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

  16. 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.

  17. 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.

  18. Toward understanding of the role of reversibility of phenotypic switching in the evolution of resistance to therapy

    Science.gov (United States)

    Horvath, D.; Brutovsky, B.

    2018-06-01

    Reversibility of state transitions is intensively studied topic in many scientific disciplines over many years. In cell biology, it plays an important role in epigenetic variation of phenotypes, known as phenotypic plasticity. More interestingly, the cell state reversibility is probably crucial in the adaptation of population phenotypic heterogeneity to environmental fluctuations by evolving bet-hedging strategy, which might confer to cancer cells resistance to therapy. In this article, we propose a formalization of the evolution of highly reversible states in the environments of periodic variability. Two interrelated models of heterogeneous cell populations are proposed and their behavior is studied. The first model captures selection dynamics of the cell clones for the respective levels of phenotypic reversibility. The second model focuses on the interplay between reversibility and drug resistance in the particular case of cancer. Overall, our results show that the threshold dependencies are emergent features of the investigated model with eventual therapeutic relevance. Presented examples demonstrate importance of taking into account cell to cell heterogeneity within a system of clones with different reversibility quantified by appropriately chosen genetic and epigenetic entropy measures.

  19. The Reversal Effects of 3-Bromopyruvate on Multidrug Resistance In Vitro and In Vivo Derived from Human Breast MCF-7/ADR Cells

    OpenAIRE

    Wu, Long; Xu, Jun; Yuan, Weiqi; Wu, Baojian; Wang, Hao; Liu, Guangquan; Wang, Xiaoxiong; Du, Jun; Cai, Shaohui

    2014-01-01

    Purpose P-glycoprotein mediated efflux is one of the main mechanisms for multidrug resistance in cancers, and 3-Bromopyruvate acts as a promising multidrug resistance reversal compound in our study. To test the ability of 3-Bromopyruvate to overcome P-glycoprotein-mediated multidrug resistance and to explore its mechanisms of multidrug resistance reversal in MCF-7/ADR cells, we evaluate the in vitro and in vivo modulatory activity of this compound. Methods The in vitro and in vivo activity wa...

  20. Role of the K101E substitution in HIV-1 reverse transcriptase in resistance to rilpivirine and other nonnucleoside reverse transcriptase inhibitors.

    Science.gov (United States)

    Xu, Hong-Tao; Colby-Germinario, Susan P; Huang, Wei; Oliveira, Maureen; Han, Yingshan; Quan, Yudong; Petropoulos, Christos J; Wainberg, Mark A

    2013-11-01

    Resistance to the recently approved nonnucleoside reverse transcriptase inhibitor (NNRTI) rilpivirine (RPV) commonly involves substitutions at positions E138K and K101E in HIV-1 reverse transcriptase (RT), together with an M184I substitution that is associated with resistance to coutilized emtricitabine (FTC). Previous biochemical and virological studies have shown that compensatory interactions between substitutions E138K and M184I can restore enzyme processivity and the viral replication capacity. Structural modeling studies have also shown that disruption of the salt bridge between K101 and E138 can affect RPV binding. The current study was designed to investigate the impact of K101E, alone or in combination with E138K and/or M184I, on drug susceptibility, viral replication capacity, and enzyme function. We show here that K101E can be selected in cell culture by the NNRTIs etravirine (ETR), efavirenz (EFV), and dapivirine (DPV) as well as by RPV. Recombinant RT enzymes and viruses containing K101E, but not E138K, were highly resistant to nevirapine (NVP) and delavirdine (DLV) as well as ETR and RPV, but not EFV. The addition of K101E to E138K slightly enhanced ETR and RPV resistance compared to that obtained with E138K alone but restored susceptibility to NVP and DLV. The K101E substitution can compensate for deficits in viral replication capacity and enzyme processivity associated with M184I, while M184I can compensate for the diminished efficiency of DNA polymerization associated with K101E. The coexistence of K101E and E138K does not impair either viral replication or enzyme fitness. We conclude that K101E can play a significant role in resistance to RPV.

  1. Doxorubicin, mesenchymal stem cell toxicity and antitumour activity: implications for clinical use.

    Science.gov (United States)

    Baxter-Holland, Mia; Dass, Crispin R

    2018-03-01

    The use of doxorubicin, an antineoplastic medication used for the treatment of cancers via mechanisms that prevent replication of cells or lead to their death, can result in damage to healthy cells as well as malignant. Among the affected cells are mesenchymal stem cells (MSCs), which are involved in the maintenance and repair of tissues in the body. This review explores the mechanisms of biological effects and damage attributed to doxorubicin on MSCs. The PubMed database was used as a source of literature for this review. Doxorubicin has the potential to lead to significant and irreversible damage to the human bone marrow environment, including MSCs. The primary known mechanism of these changes is through free radical damage and activation of apoptotic pathways. The presence of MSCs in culture or in vivo appears to either suppress or promote tumour growth. Interactions between doxorubicin and MSCs have the potential to increase chemotherapy resistance. Doxorubicin-induced damage to MSCs is of concern clinically. However, MSCs also have been associated with resistance of tumour cells to drugs including doxorubicin. Further studies, particularly in vivo, are needed to provide consistent results of how the doxorubicin-induced changes to MSCs affect treatment and patient health. © 2018 Royal Pharmaceutical Society.

  2. Dasatinib and Doxorubicin Treatment of Sarcoma Initiating Cells: A Possible New Treatment Strategy

    Directory of Open Access Journals (Sweden)

    Ninna Aggerholm-Pedersen

    2016-01-01

    Full Text Available Background. One of the major challenges affecting sarcoma treatment outcome, particularly that of metastatic disease, is resistance to chemotherapy. Cancer-initiating cells are considered a major contributor to this resistance. Methods. An immortalised nontransformed human stromal (mesenchymal stem cell line hMSC-TERT4 and a transformed cell line hMSC-TERT20-CE8, known to form sarcoma-like tumours when implanted in immune-deficient mice, were used as models. Receptor tyrosine kinase (RTK activation was analysed by RTK arrays and cellular viability after tyrosine kinases inhibitor (TKI treatment with or without doxorubicin was assessed by MTS assay. Results. Initial results showed that the hMSC-TERT4 was more doxorubicin-sensitive while hMSC-TERT20-CE8 was less doxorubicin-sensitive evidenced by monitoring cell viability in the presence of doxorubicin at different doses. The epidermal growth factor receptor (EGFR was activated in both cell lines. However hMSC-TERT20-CE8 exhibited significantly higher expression of the EGFR ligands. EGFR inhibitors such as erlotinib and afatinib alone or in combination with doxorubicin failed to further decrease cell viability of hMSC-TERT20-CE8. However, inhibition with the TKI dasatinib in combination with doxorubicin decreased cell viability of the hMSC-TERT20-CE8 cell line. Conclusion. Our results demonstrate that dasatinib, but not EGFR-directed treatment, can decrease cell viability of stromal cancer stem cells less sensitive to doxorubicin.

  3. Dasatinib and Doxorubicin Treatment of Sarcoma Initiating Cells: A Possible New Treatment Strategy.

    Science.gov (United States)

    Aggerholm-Pedersen, Ninna; Demuth, Christina; Safwat, Akmal; Meldgaard, Peter; Kassem, Moustapha; Sandahl Sorensen, Boe

    2016-01-01

    Background. One of the major challenges affecting sarcoma treatment outcome, particularly that of metastatic disease, is resistance to chemotherapy. Cancer-initiating cells are considered a major contributor to this resistance. Methods. An immortalised nontransformed human stromal (mesenchymal) stem cell line hMSC-TERT4 and a transformed cell line hMSC-TERT20-CE8, known to form sarcoma-like tumours when implanted in immune-deficient mice, were used as models. Receptor tyrosine kinase (RTK) activation was analysed by RTK arrays and cellular viability after tyrosine kinases inhibitor (TKI) treatment with or without doxorubicin was assessed by MTS assay. Results. Initial results showed that the hMSC-TERT4 was more doxorubicin-sensitive while hMSC-TERT20-CE8 was less doxorubicin-sensitive evidenced by monitoring cell viability in the presence of doxorubicin at different doses. The epidermal growth factor receptor (EGFR) was activated in both cell lines. However hMSC-TERT20-CE8 exhibited significantly higher expression of the EGFR ligands. EGFR inhibitors such as erlotinib and afatinib alone or in combination with doxorubicin failed to further decrease cell viability of hMSC-TERT20-CE8. However, inhibition with the TKI dasatinib in combination with doxorubicin decreased cell viability of the hMSC-TERT20-CE8 cell line. Conclusion. Our results demonstrate that dasatinib, but not EGFR-directed treatment, can decrease cell viability of stromal cancer stem cells less sensitive to doxorubicin.

  4. A 3D QSAR pharmacophore model and quantum chemical structure--activity analysis of chloroquine(CQ)-resistance reversal.

    Science.gov (United States)

    Bhattacharjee, Apurba K; Kyle, Dennis E; Vennerstrom, Jonathan L; Milhous, Wilbur K

    2002-01-01

    Using CATALYST, a three-dimensional QSAR pharmacophore model for chloroquine(CQ)-resistance reversal was developed from a training set of 17 compounds. These included imipramine (1), desipramine (2), and 15 of their analogues (3-17), some of which fully reversed CQ-resistance, while others were without effect. The generated pharmacophore model indicates that two aromatic hydrophobic interaction sites on the tricyclic ring and a hydrogen bond acceptor (lipid) site at the side chain, preferably on a nitrogen atom, are necessary for potent activity. Stereoelectronic properties calculated by using AM1 semiempirical calculations were consistent with the model, particularly the electrostatic potential profiles characterized by a localized negative potential region by the side chain nitrogen atom and a large region covering the aromatic ring. The calculated data further revealed that aminoalkyl substitution at the N5-position of the heterocycle and a secondary or tertiary aliphatic aminoalkyl nitrogen atom with a two or three carbon bridge to the heteroaromatic nitrogen (N5) are required for potent "resistance reversal activity". Lowest energy conformers for 1-17 were determined and optimized to afford stereoelectronic properties such as molecular orbital energies, electrostatic potentials, atomic charges, proton affinities, octanol-water partition coefficients (log P), and structural parameters. For 1-17, fairly good correlation exists between resistance reversal activity and intrinsic basicity of the nitrogen atom at the tricyclic ring system, frontier orbital energies, and lipophilicity. Significantly, nine out of 11 of a group of structurally diverse CQ-resistance reversal agents mapped very well on the 3D QSAR pharmacophore model.

  5. Anticancer and reversing multidrug resistance activities of natural isoquinoline alkaloids and their structure-activity relationship.

    Science.gov (United States)

    Qing, Zhi-Xing; Huang, Jia-Lu; Yang, Xue-Yi; Liu, Jing-Hong; Cao, Hua-Liang; Xiang, Feng; Cheng, Pi; Zeng, Jian-Guo

    2017-09-20

    The severe anticancer situation as well as the emergence of multidrug-resistant (MDR) cancer cells has created an urgent need for the development of novel anticancer drugs with different mechanisms of action. A large number of natural alkaloids, such as paclitaxel, vinblastine and camptothecin have already been successfully developed into chemotherapy agents. Following the success of these natural products, in this review, twenty-six types of isoquinoline alkaloid (a total of 379 alkaloids), including benzyltetrahydroisoquinoline, aporphine, oxoaporphine, isooxoaporphine, dimeric aporphine, bisbenzylisoquinoline, tetrahydroprotoberberine, protoberberine, protopine, dihydrobenzophenanthridine, benzophenanthridine, benzophenanthridine dimer, ipecac, simple isoquinoline, pavine, montanine, erythrina, chelidonine, tropoloisoquinoline, azafluoranthene, phthalideisoquinoline, naphthylisoquinoline, lycorine, crinane, narciclasine, and phenanthridone, were summarized based on their cytotoxic and MDR reversing activities against various cancer cells. Additionally, the structure-activity relationships of different types of isoquinoline alkaloid were also discussed. Interestingly, some aporphine, oxoaporphine, isooxoaporphine, bisbenzylisoquinoline, and protoberberine alkaloids display more potent anticancer activities or anti-MDR effects than positive control against the tested cancer cells and are regarded as attractive targets for discovery new anticancer drugs or lead compounds. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  6. 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.

  7. Analysis of resistive tearing-mode in the reversed-field pinch plasma

    International Nuclear Information System (INIS)

    Oshiyama, Hiroshi; Masamune, Sadao; Hamuro, Eitaro; Tamaki, Reiji.

    1985-01-01

    As one of the methods of confining high temperature plasma by magnetic stress, attention has been paid to reversed field pinch (RFP). This RFP is the method of maintaining plasma pressure by combining the poloidal field generated by plasma current and the toroidal field having nearly same intensity, thus forming the toroidal shape, closed magnetic surface. As the typical RFP equipment, there have been TPE-1R(M), HBTX-1A, ZT-40M and OHTE, but in order to anticipate the further development, one of the problems is the resistive instability. In this study, the critical beta value determined by the tearing mode in RFP configuration was examined by analytical and numerical calculation methods. The position of a wall required for the stability was determined by solving a second order differential equation for a radial perturbed magnetic field. The propriety of the computer code for determining the position was examined. The magnetic field configuration having a finite beta value was determined, and its stability against a tearing mode was investigated. For this judgement of the stability, the developed computer code was used. The tearing mode in a Bessel function model, the tearing mode of a finite beta value and others are described. (Kako, I.)

  8. 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.

  9. Reversible Adaptive Plasticity: A Mechanism for Neuroblastoma Cell Heterogeneity and Chemo-Resistance

    Energy Technology Data Exchange (ETDEWEB)

    Chakrabarti, Lina; Abou-Antoun, Thamara; Vukmanovic, Stanislav; Sandler, Anthony D., E-mail: asandler@childrensnational.org [The Joseph E. Robert Center for Surgical Care, Children’s National Medical Center, Washington, DC (United States); The Sheikh Zayed Institute for Pediatric Surgical Innovation, Children’s National Medical Center, Washington, DC (United States)

    2012-08-02

    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.

  10. Cytotoxic and multidrug resistance reversal activity of a vegetable, 'Anastasia Red', a variety of sweet pepper.

    Science.gov (United States)

    Motohashi, Noboru; Wakabayashi, Hidetsugu; Kurihara, Teruo; Takada, Yuko; Maruyama, Shichiro; Sakagami, Hiroshi; Nakashima, Hideki; Tani, Satoru; Shirataki, Yoshiaki; Kawase, Masami; Wolfard, Kristina; Molnár, Joseph

    2003-04-01

    The vegetable, Anastasia Red, Capsicum annuum L. var. angulosum Mill. (Solanaceae) was successively extracted with hexane, acetone, methanol and 70% methanol, and the extracts were further separated into a total of 21 fractions by silica gel or octadecylsilane (ODS) column chromatography. The biological activities of extracts and fractions were determined. These extracts showed relatively higher cytotoxic activity against two human oral tumor cell lines (HSC-2, HSG) than against normal human gingival fibroblasts (HGF), suggesting a tumor-specific cytotoxic activity. The cytotoxic activity of these extracts was enhanced by fractionation on silica gel [H2, A2, M1-M3] or ODS column chromatography [70M]. Several fractions [H2, H4, H5, A1, A2, A3, A5, A6, A7, M2] reversed the multidrug resistance (MDR) phenotype with L5178 mouse lymphoma T cells, more efficiently than (+/-)-verapamil. The extracts and fractions did not show any detectable anti-human immunodeficiency virus (HIV) or anti-Helicobacter pylori activity. Thus, this study suggests the effective and selective antitumor potential of 'Anastasia Red' of sweet pepper for further phytochemical and biological investigation. Copyright 2003 John Wiley & Sons, Ltd.

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

    Science.gov (United States)

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

    2016-07-26

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

  12. A mechanism for overcoming P-glycoprotein-mediated drug resistance: novel combination therapy that releases stored doxorubicin from lysosomes via lysosomal permeabilization using Dp44mT or DpC.

    Science.gov (United States)

    Seebacher, Nicole A; Richardson, Des R; Jansson, Patric J

    2016-12-01

    The intracellular distribution of a drug can cause significant variability in both activity and selectivity. Herein, we investigate the mechanism by which the anti-cancer agents, di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT) and the clinically trialed, di-2-pyridylketone 4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC), re-instate the efficacy of doxorubicin (DOX), in drug-resistant P-glycoprotein (Pgp)-expressing cells. Both Dp44mT and DpC potently target and kill Pgp-expressing tumors, while DOX effectively kills non-Pgp-expressing cancers. Thus, the combination of these agents should be considered as an effective rationalized therapy for potently treating advanced and resistant tumors that are often heterogeneous in terms of Pgp-expression. These studies demonstrate that both Dp44mT and DpC are transported into lysosomes via Pgp transport activity, where they induce lysosomal-membrane permeabilization to release DOX trapped within lysosomes. This novel strategy of loading lysosomes with DOX, followed by permeabilization with Dp44mT or DpC, results in the relocalization of stored DOX from its lysosomal 'safe house' to its nuclear targets, markedly enhancing cellular toxicity against resistant tumor cells. Notably, the combination of Dp44mT or DpC with DOX showed a very high level of synergism in multiple Pgp-expressing cell types, for example, cervical, breast and colorectal cancer cells. These studies revealed that the level of drug synergy was proportional to Pgp activity. Interestingly, synergism was ablated by inhibiting Pgp using the pharmacological inhibitor, Elacridar, or by inhibiting Pgp-expression using Pgp-silencing, demonstrating the importance of Pgp in the synergistic interaction. Furthermore, lysosomal-membrane stabilization inhibited the relocalization of DOX from lysosomes to the nucleus upon combination with Dp44mT or DpC, preventing synergism. This latter observation demonstrated the importance of lysosomal

  13. 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

  14. SKLB060 Reversibly Binds to Colchicine Site of Tubulin and Possesses Efficacy in Multidrug-Resistant Cell Lines.

    Science.gov (United States)

    Yan, Wei; Yang, Tao; Yang, Jianhong; Wang, Taijin; Yu, Yamei; Wang, Yuxi; Chen, Qiang; Bai, Peng; Li, Dan; Ye, Haoyu; Qiu, Qiang; Zhou, Yongzhao; Hu, Yiguo; Yang, Shengyong; Wei, Yuquan; Li, Weimin; Chen, Lijuan

    2018-05-22

    Many tubulin inhibitors are in clinical use as anti-cancer drugs. In our previous study, a novel series of 4-substituted coumarins derivatives were identified as novel tubulin inhibitors. Here, we report the anti-cancer activity and underlying mechanism of one of the 4-substituted coumarins derivatives (SKLB060). The anti-cancer activity of SKLB060 was tested on 13 different cancer cell lines and four xenograft cancer models. Immunofluorescence staining, cell cycle analysis, and tubulin polymerization assay were employed to study the inhibition of tubulin. N, N '-Ethylenebis(iodoacetamide) assay was used to measure binding to the colchicine site. Wound-healing migration and tube formation assays were performed on human umbilical vascular endothelial cells to study anti-vascular activity (the ability to inhibit blood vessel growth). Mitotic block reversibility and structural biology assays were used to investigate the SKLB060-tubulin bound model. SKLB060 inhibited tubulin polymerization and subsequently induced G2/M cell cycle arrest and apoptosis in cancer cells. SKLB060 bound to the colchicine site of β-tubulin and showed antivascular activity in vitro. Moreover, SKLB060 induced reversible cell cycle arrest and reversible inhibition of tubulin polymerization. A mitotic block reversibility assay showed that the effects of SKLB060 have greater reversibility than those of colcemid (a reversible tubulin inhibitor), indicating that SKLB060 binds to tubulin in a totally reversible manner. The crystal structures of SKLB060-tubulin complexes confirmed that SKLB060 binds to the colchicine site, and the natural coumarin ring in SKLB060 enables reversible binding. These results reveal that SKLB060 is a powerful and reversible microtubule inhibitor that binds to the colchicine site and is effective in multidrug-resistant cell lines. © 2018 The Author(s). Published by S. Karger AG, Basel.

  15. 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...

  16. Trends of drug-resistance-associated mutations in the reverse transcriptase gene of HIV type 1 isolates from North India.

    Science.gov (United States)

    Azam, Mohd; Malik, Abida; Rizvi, Meher; Rai, Arvind

    2014-04-01

    A major cause of failure of antiretroviral therapy (ART) is the presence of drug-resistance-associated mutations in the polymerase gene of HIV-1. The paucity of data regarding potential drug resistance to reverse transcriptase inhibitors (RTIs) prompted us to carry out this study. This information will shed light on the extent of drug resistance already present in HIV strains and will give future directions in patient treatment and in drug design. Drug resistance genotyping of a partial reverse transcriptase gene was done in 103 HIV-1-infected patients, including the ART-naive and ART-experienced population. The drug resistance pattern was analyzed using the Stanford HIV-DR database, the IAS-USA mutation list and the REGA algorithm-v8.0. Subtyping was done using the REGA HIV-1 subtyping tool-v2.01. The majority of our sequences (96 %) were found to be subtype C, and four (3.8 %) were subtype A1. Significant prevalence of DR mutations (28 %) was observed in the RT gene. Major amino acid substitutions were seen at positions 41, 90, 98, 103, 106, 108, 138, 181, 184, 190, 215, and 219, which confer high/intermediate levels of resistance to most RTIs, independently or together. Our results show that there is an urgent need to tailor ART drug regimens to the individual to achieve optimum therapeutic outcome in North India.

  17. Preparation of psoralen polymer-lipid hybrid nanoparticles and their reversal of multidrug resistance in MCF-7/ADR cells.

    Science.gov (United States)

    Huang, Qingqing; Cai, Tiange; Li, Qianwen; Huang, Yinghong; Liu, Qian; Wang, Bingyue; Xia, Xi; Wang, Qi; Whitney, John C C; Cole, Susan P C; Cai, Yu

    2018-11-01

    Multidrug resistance (MDR) is the leading cause of failure for breast cancer in the clinic. Thus far, polymer-lipid hybrid nanoparticles (PLN) loaded chemotherapeutic agents has been used to overcome MDR in breast cancer. In this study, we prepared psoralen polymer-lipid hybrid nanoparticles (PSO-PLN) to reverse drug resistant MCF-7/ADR cells in vitro and in vivo. PSO-PLN was prepared by the emulsification evaporation-low temperature solidification method. The formulation, water solubility and bioavailability, particle size, zeta potential and entrapment efficiency, and in vitro release experiments were optimized in order to improve the activity of PSO to reverse MDR. Optimal formulation: soybean phospholipids 50 mg, poly(lactic-co-glycolic) acid (PLGA) 15 mg, PSO 3 mg, and Tween-80 1%. The PSO-PLN possessed a round appearance, uniform size, exhibited no adhesion. The average particle size was 93.59 ± 2.87 nm, the dispersion co-efficient was 0.249 ± 0.06, the zeta potential was 25.47 ± 2.84 mV. In vitro analyses revealed that PSO resistance index was 3.2, and PSO-PLN resistance index was 5.6, indicating that PSO-PLN versus MCF-7/ADR reversal effect was significant. Moreover, PSO-PLN is somewhat targeted to the liver, and has an antitumor effect in the xenograft model of drug-resistant MCF-7/ADR cells. In conclusion, PSO-PLN not only reverses MDR but also improves therapeutic efficiency by enhancing sustained release of PSO.

  18. 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.Rat.in_vivo.Liver.Single.zip ftp://ftp.biosciencedbc.jp/...archive/open-tggates/LATEST/Rat/in_vivo/Liver/Repeat/doxorubicin.Rat.in_vivo.Liver.Repeat.zip ftp://ftp.bios

  19. Reversal of the multidrug resistance by drug combination using multifunctional liposomes

    Science.gov (United States)

    Patel, Niravkumar R.

    One of the major obstacles to the success of cancer chemotherapy is the multi-drug resistance (MDR) that results due mainly to the over-expression of drug efflux transporter pumps such as P-glycoprotein (P-gp). Highly efficacious third generation P-gp inhibitors, like tariquidar, have shown promising results against MDR. However, P-gp is also expressed in normal tissues like the blood-brain barrier, gastrointestinal tract, liver and kidney. It is therefore important to limit the exposure of P-gp inhibitors to normal tissues and increase their co-localization with anticancer agents in tumor tissues to maximize the efficacy of a P-gp inhibitor. To minimize non-specific binding and increase its delivery to tumor tissues, liposomes, self-assembling phospholipid vesicles, were chosen as a drug delivery vehicle. The liposome has been identified as a system capable of carrying molecules with diverse physicochemical properties. It can also alter the pharmacokinetic profile of loaded molecules which is a concern with both tariquidar and paclitaxel. Liposomes can easily be surface-modified rendering them cell-specific as well as organelle-specific. The main objective of present study was to develop an efficient liposomal delivery system which would deliver therapeutic molecules of interest to tumor tissues and avoid interaction with normal tissues. In this study, the co-delivery of tariquidar and paclitaxel into tumor cells to reverse the MDR using long-circulating cationic liposomes was investigated. SKOV-3TR, the resistant variant of SKOV-3 and MCF-7/ADR, the resistant variant of MCF-7 were used as model cell lines. Uniform liposomal formulations were generated with high incorporation efficiency and no apparent decrease in tariquidar potency towards P-gp. Tariquidar- and paclitaxel- co-loaded long-circulating liposomes showed significant re-sensitization of SKOV-3TR and MCF-7/ADR for paclitaxel in vitro. Further modification of these liposomes with antitumor 2C5 resulted

  20. Caffeine ingestion reverses the circadian rhythm effects on neuromuscular performance in highly resistance-trained men.

    Directory of Open Access Journals (Sweden)

    Ricardo Mora-Rodríguez

    Full Text Available PURPOSE: To investigate whether caffeine ingestion counteracts the morning reduction in neuromuscular performance associated with the circadian rhythm pattern. METHODS: Twelve highly resistance-trained men underwent a battery of neuromuscular tests under three different conditions; i morning (10:00 a.m. with caffeine ingestion (i.e., 3 mg kg(-1; AM(CAFF trial; ii morning (10:00 a.m. with placebo ingestion (AM(PLAC trial; and iii afternoon (18:00 p.m. with placebo ingestion (PM(PLAC trial. A randomized, double-blind, crossover, placebo controlled experimental design was used, with all subjects serving as their own controls. The neuromuscular test battery consisted in the measurement of bar displacement velocity during free-weight full-squat (SQ and bench press (BP exercises against loads that elicit maximum strength (75% 1RM load and muscle power adaptations (1 m s(-1 load. Isometric maximum voluntary contraction (MVC(LEG and isometric electrically evoked strength of the right knee (EVOK(LEG were measured to identify caffeine's action mechanisms. Steroid hormone levels (serum testosterone, cortisol and growth hormone were evaluated at the beginning of each trial (PRE. In addition, plasma norepinephrine (NE and epinephrine were measured PRE and at the end of each trial following a standardized intense (85% 1RM 6 repetitions bout of SQ (POST. RESULTS: In the PM(PLAC trial, dynamic muscle strength and power output were significantly enhanced compared with AM(PLAC treatment (3.0%-7.5%; p≤0.05. During AM(CAFF trial, muscle strength and power output increased above AM(PLAC levels (4.6%-5.7%; p≤0.05 except for BP velocity with 1 m s(-1 load (p = 0.06. During AM(CAFF, EVOK(LEG and NE (a surrogate of maximal muscle sympathetic nerve activation were increased above AM(PLAC trial (14.6% and 96.8% respectively; p≤0.05. CONCLUSIONS: These results indicate that caffeine ingestion reverses the morning neuromuscular declines in highly resistance

  1. Linear studies of resistive interchange modes in a cylindrical reversed field pinch

    International Nuclear Information System (INIS)

    Mirin, A.A.; O'Neill, N.J.; Killeen, J.; Bonugli, R.J.; Ellis, M.J.

    1986-01-01

    Resistive interchange modes in a cylindrical reversed field pinch are studied using a one-dimensional, linear, compressible initial value code. Separate equations for the electron and ion temperature perturbations are solved. Hall terms and the thermal force vector are included in Ohm's law. Anisotropic thermal conductivity and viscosity are included in the code model. Calculations are carried out for various values of poloidal and toroidal mode number, Lundquist number, Suydam parameter, Hall parameter, thermal conductivity, viscosity, etc., with respect to uniform density equilibria known to be stable to tearing modes. It is shown that in the cold ion limit sufficiently large Hall terms cause all modes that are tested to become stable. However for T/sub i/ = T/sub e/ and ignoring the effects of viscosity and thermal conductivity, there is a critical value of the ratio of Alfven to ion cyclotron frequency above which the ''even'' mode not only dominates the ''odd'' mode but is likely to have a growth rate significantly larger than that of the odd mode in the absence of Hall terms. Inclusion of a classical tensor thermal conductivity, while having little effect on the odd mode in the absence of Hall terms, does stabilize the even mode for sufficiently large Hall parameter. Inclusion of a classical tensor viscosity reduces the growth rate of (but does not necessarily stabilize) the odd mode. Inclusion of Hall and thermal force terms, tensor thermal conductivity and tensor viscosity causes all modes that are tested to stabilize. Results are compared to other contemporary studies

  2. Acacetin enhances the therapeutic efficacy of doxorubicin in non-small-cell lung carcinoma cells.

    Directory of Open Access Journals (Sweden)

    Reenu Punia

    Full Text Available Anthracyclines are efficient and potent agents to treat broad range of cancers but cytotoxicity induced by them limits their use in therapeutics. Use of plant-derived agents help to prevent or delay the process of cancer progression and their combination increases the anti-cancer potential of mainstream compound. However, multidrug resistance is major cause of treatment failure in cancer patients.In this study, combination treatments of fisetin or acacetin with doxorubicin were explored for their potential synergistic effect on non-small-cell lung carcinoma (NSCLC cells.During this study, NSCLC model cell lines A549 and H1299 were used to determine the combinatorial effect of phytochemicals namly acacetin and fisetin with doxorubicin.The effects of individual compounds and their combination on cell viability, clonogenic potential and cell cycle progression were studied. Efflux of doxorubicin was measured by spectrofluorophotometer, whereas accumulation inside the cells was analyzed by flow cytometry and confocal microscopy. Expression of MDR1 was checked by semi-quantitative PCR.The results showed that the cell viability of A549 and H1299 cells were significantly decreased in time- and dose-dependent manner, although A549 cells showed more sensitivity toward doxorubicin than H1299 cells. Mostly, combination of doxorubicin showed good synergy with acacetin in both the cell lines whereas, fisetin exerted synergistic effect only at 72 h of treatment in H1299 cells. Acacetin with doxorubicin caused G2/M arrest by downregulating CDK-cyclin complex in A549 cells. Acacetin-doxorubicin combination decreased the clonogenic potential of A549 and H1299 cells upto 82% and 59%, respectively, as compared to control. Acacetin also decreased efflux of doxorubicin by 59% after 30 mins of exposure to A549 cells and further increased accumulation of doxorubicin inside the cells upto 55% in 2 h. The modulatory effect of acacetin-doxorubicin combination on

  3. 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.

  4. Comparison of cutout resistance of dynamic condylar screw and proximal femoral nail in reverse oblique trochanteric fractures: A biomechanical study

    Directory of Open Access Journals (Sweden)

    Gursimrat Singh Cheema

    2012-01-01

    Results: The bending moment of the PFN group was approximately 50% less than that of the DCS group (P<0.0001. The PFN group resisted more number of cycles than the DCS group (P=0.03 and showed lesser number of component failures as compared with the DCS group (P=0.003. Conclusions: The PFN is biomechanically superior to DCS for the fixation of reverse oblique trochanteric fractures of femur.

  5. Neratinib Reverses ATP-Binding Cassette B1-Mediated Chemotherapeutic Drug Resistance In Vitro, In Vivo, and Ex Vivo

    OpenAIRE

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

    2012-01-01

    Neratinib, an irreversible inhibitor of epidermal growth factor receptor and human epidermal receptor 2, is in phase III clinical trials for patients with human epidermal receptor 2-positive, locally advanced or metastatic breast cancer. The objective of this study was to explore the ability of neratinib to reverse tumor multidrug resistance attributable to overexpression of ATP-binding cassette (ABC) transporters. Our results showed that neratinib remarkably enhanced the sensitivity of ABCB1...

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

    KAUST Repository

    Shen, Shida; Williamson, Morgan; Cao, Gang; Zhou, Jianshi; Goodenough, John; Tsoi, Maxim

    2017-01-01

    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

  7. 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.

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

    Science.gov (United States)

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

    2017-11-28

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

  9. Molecular Modification of Metadherin/MTDH Impacts the Sensitivity of Breast Cancer to Doxorubicin.

    Directory of Open Access Journals (Sweden)

    Zhenchuan Song

    Full Text Available Breast cancer is a leading cause of death in women and with an increasing worldwide incidence. Doxorubicin, as a first-line anthracycline-based drug is conventional used on breast cancer clinical chemotherapy. However, the drug resistances limited the curative effect of the doxorubicin therapy in breast cancer patients, but the molecular mechanism determinants of breast cancer resistance to doxorubicin chemotherapy are not fully understood. In order to explore the association between metadherin (MTDH and doxorubicin sensitivity, the differential expressions of MTDH in breast cancer cell lines and the sensitivity to doxorubicin of breast cancer cell lines were investigated.The mRNA and protein expression of MTDH were determined by real-time PCR and Western blot in breast cancer cells such as MDA-MB-231, MCF-7, MDA-MB-435S, MCF-7/ADR cells. Once MTDH gene was knocked down by siRNA in MCF-7/ADR cells and overexpressed by MTDH plasmid transfection in MDA-MB-231 cells, the cell growth and therapeutic sensitivity of doxorubicin were evaluated using MTT and the Cell cycle assay and apoptosis rate was determined by flow cytometry.MCF-7/ADR cells revealed highly expressed MTDH and MDA-MB-231 cells had the lowest expression of MTDH. After MTDH gene was knocked down, the cell proliferation was inhibited, and the inhibitory rate of cell growth and apoptosis rate were enhanced, and the cell cycle arrest during the G0/G1 phase in the presence of doxorubicin treatment. On the other hand, the opposite results were observed in MDA-MB-231 cells with overexpressed MTDH gene.MTDH gene plays a promoting role in the proliferation of breast cancer cells and its high expression may be associated with doxorubicin sensitivity of breast cancer.

  10. Synergistic Effect of Endogenous and Exogenous Aldehydes on Doxorubicin Toxicity in Yeast

    Directory of Open Access Journals (Sweden)

    Jana S. Miles

    2018-01-01

    Full Text Available Anthracyclines are frequently used to treat many cancers including triple negative breast cancer, which is commonly observed in African-American women (AA, and tend to be more aggressive, carry worse prognoses, and are harder to manage because they lack molecular targets. Although effective, anthracyclines use can be limited by serious side effects and eventually the development of drug resistance. In S. cerevisiae, mutants of HOM6 display hypersensitivity to doxorubicin. HOM6 is required for synthesis of threonine and interruption of the pathway leads to accumulation of the threonine intermediate L-aspartate-semialdehyde. This intermediate may synergize with doxorubicin to kill the cell. In fact, deleting HOM3 in the first step, preventing the pathway to reach the HOM6 step, rescues the sensitivity of the hom6 strain to doxorubicin. Using several S. cerevisiae strains (wild type, hom6, hom3, hom3hom6, ydj1, siz1, and msh2, we determined their sensitivity to aldehydes and to their combination with doxorubicin, cisplatin, and etoposide. Combination of formaldehyde and doxorubicin was most effective at reducing cell survival by 31-fold–39-fold (in wild type cells relative to doxorubicin and formaldehyde alone. This effect was dose dependent on doxorubicin. Cotreatment with formaldehyde and doxorubicin also showed increased toxicity in anthracycline-resistant strains siz1 and msh2. The hom6 mutant also showed sensitivity to menadione with a 2.5-fold reduction in cell survival. The potential use of a combination of aldehydes and cytotoxic drugs could potentially lead to applications intended to enhance anthracycline-based therapy.

  11. Influence of the proton pump inhibitor lansoprazole on distribution and activity of doxorubicin in solid tumors.

    Science.gov (United States)

    Yu, Man; Lee, Carol; Wang, Marina; Tannock, Ian F

    2015-10-01

    Cellular causes of resistance and limited drug distribution within solid tumors limit therapeutic efficacy of anticancer drugs. Acidic endosomes in cancer cells mediate autophagy, which facilitates survival of stressed cells, and may contribute to drug resistance. Basic drugs (e.g. doxorubicin) are sequestered in acidic endosomes, thereby diverting drugs from their target DNA and decreasing penetration to distal cells. Proton pump inhibitors (PPIs) may raise endosomal pH, with potential to improve drug efficacy and distribution in solid tumors. We determined the effects of the PPI lansoprazole to modify the activity of doxorubicin. To gain insight into its mechanisms, we studied the effects of lansoprazole on endosomal pH, and on the spatial distribution of doxorubicin, and of biomarkers reflecting its activity, using in vitro and murine models. Lansoprazole showed concentration-dependent effects to raise endosomal pH and to inhibit endosomal sequestration of doxorubicin in cultured tumor cells. Lansoprazole was not toxic to cancer cells but potentiated the cytotoxicity of doxorubicin and enhanced its penetration through multilayered cell cultures. In solid tumors, lansoprazole improved the distribution of doxorubicin but also increased expression of biomarkers of drug activity throughout the tumor. Combined treatment with lansoprazole and doxorubicin was more effective in delaying tumor growth as compared to either agent alone. Together, lansoprazole enhances the therapeutic effects of doxorubicin both by improving its distribution and increasing its activity in solid tumors. Use of PPIs to improve drug distribution and to inhibit autophagy represents a promising strategy to enhance the effectiveness of anticancer drugs in solid tumors. © 2015 The Authors. Cancer Science published by Wiley Publishing Asia Pty Ltd on behalf of Japanese Cancer Association.

  12. 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....

  13. 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.

  14. Doxorubicin induced myocardial injury is exacerbated following ischaemic stress via opening of the mitochondrial permeability transition pore

    Energy Technology Data Exchange (ETDEWEB)

    Gharanei, M.; Hussain, A. [Department of Biomolecular and Sport Sciences, Coventry University, Cox Street, Coventry, CV1 5FB (United Kingdom); Janneh, O. [Department of Biomolecular and Sport Sciences, Coventry University, Cox Street, Coventry, CV1 5FB (United Kingdom); Pharmacology Research Laboratories, 70, Pembroke Place, The University of Liverpool, Liverpool. L69 3GF (United Kingdom); Maddock, H.L., E-mail: h.maddock@coventry.ac.uk [Department of Biomolecular and Sport Sciences, Coventry University, Cox Street, Coventry, CV1 5FB (United Kingdom)

    2013-04-15

    Chemotherapeutic agents such as doxorubicin are known to cause or exacerbate cardiovascular cell death when an underlying heart condition is present. However, the mechanism of doxorubicin-induced cardiotoxicity is unclear. Here we assess the cardiotoxic effects of doxorubicin in conditions of myocardial ischaemia reperfusion and the mechanistic basis of protection, in particular the role of the mitochondrial permeability transition pore (mPTP) in such protection. The effects of doxorubicin (1 μM) ± cyclosporine A (CsA, 0.2 μM; inhibits mPTP) were investigated in isolated male Sprague–Dawley rats using Langendorff heart and papillary muscle contraction models subjected to simulated ischaemia and reperfusion injury. Isolated rat cardiac myocytes were used in an oxidative stress model to study the effects of drug treatment on mPTP by confocal microscopy. Western blot analysis evaluated the effects of drug treatment on p-Akt and p-Erk 1/2 levels. Langendorff and the isometric contraction models showed a detrimental effect of doxorubicin throughout reperfusion/reoxygenation as well as increased p-Akt and p-Erk levels. Interestingly, CsA not only reversed the detrimental effects of doxorubicin, but also reduced p-Akt and p-Erk levels. In the sustained oxidative stress assay to study mPTP opening, doxorubicin decreased the time taken to depolarization and hypercontracture, but these effects were delayed in the presence of CsA. Collectively, our data suggest for the first that doxorubicin exacerbates myocardial injury in an ischaemia reperfusion model. If the inhibition of mPTP ameliorates the cardiotoxic effects of doxorubicin, then more selective inhibitors of mPTP should be further investigated for their utility in patients receiving doxorubicin. - Highlights: ► Doxorubicin exacerbates myocardial ischaemia reperfusion injury. ► Co-treatment with CsA protects against doxorubicin induced myocardial injury. ► CsA delays doxorubicin induced mPTP opening in laser

  15. Doxorubicin induced myocardial injury is exacerbated following ischaemic stress via opening of the mitochondrial permeability transition pore

    International Nuclear Information System (INIS)

    Gharanei, M.; Hussain, A.; Janneh, O.; Maddock, H.L.

    2013-01-01

    Chemotherapeutic agents such as doxorubicin are known to cause or exacerbate cardiovascular cell death when an underlying heart condition is present. However, the mechanism of doxorubicin-induced cardiotoxicity is unclear. Here we assess the cardiotoxic effects of doxorubicin in conditions of myocardial ischaemia reperfusion and the mechanistic basis of protection, in particular the role of the mitochondrial permeability transition pore (mPTP) in such protection. The effects of doxorubicin (1 μM) ± cyclosporine A (CsA, 0.2 μM; inhibits mPTP) were investigated in isolated male Sprague–Dawley rats using Langendorff heart and papillary muscle contraction models subjected to simulated ischaemia and reperfusion injury. Isolated rat cardiac myocytes were used in an oxidative stress model to study the effects of drug treatment on mPTP by confocal microscopy. Western blot analysis evaluated the effects of drug treatment on p-Akt and p-Erk 1/2 levels. Langendorff and the isometric contraction models showed a detrimental effect of doxorubicin throughout reperfusion/reoxygenation as well as increased p-Akt and p-Erk levels. Interestingly, CsA not only reversed the detrimental effects of doxorubicin, but also reduced p-Akt and p-Erk levels. In the sustained oxidative stress assay to study mPTP opening, doxorubicin decreased the time taken to depolarization and hypercontracture, but these effects were delayed in the presence of CsA. Collectively, our data suggest for the first that doxorubicin exacerbates myocardial injury in an ischaemia reperfusion model. If the inhibition of mPTP ameliorates the cardiotoxic effects of doxorubicin, then more selective inhibitors of mPTP should be further investigated for their utility in patients receiving doxorubicin. - Highlights: ► Doxorubicin exacerbates myocardial ischaemia reperfusion injury. ► Co-treatment with CsA protects against doxorubicin induced myocardial injury. ► CsA delays doxorubicin induced mPTP opening in laser

  16. Effects of multiple resistive shells and transient electromagnetic torque on the dynamics of mode locking in reversed field pinch plasmas

    International Nuclear Information System (INIS)

    Guo, S.C.; Chu, M.S.

    2002-01-01

    The effects of multiple resistive shells and transient electromagnetic torque on the dynamics of mode locking in the reversed field pinch (RFP) plasmas are studied. Most RFP machines are equipped with one or more metal shells outside of the vacuum vessel. These shells have finite resistivities. The eddy currents induced in each of the shells contribute to the braking electromagnetic (EM) torque which slows down the plasma rotation. In this work we study the electromagnetic torque acting on the plasma (tearing) modes produced by a system of resistive shells. These shells may consist of several nested thin shells or several thin shells enclosed within a thick shell. The dynamics of the plasma mode is investigated by balancing the EM torque from the resistive shells with the plasma viscous torque. Both the steady state theory and the time-dependent theory are developed. The steady state theory is shown to provide an accurate account of the resultant EM torque if (dω/dt)ω -2 <<1 and the time scale of interest is much longer than the response (L/R) time of the shell. Otherwise, the transient theory should be adopted. As applications, the steady state theory is used to evaluate the changes of the EM torque response from the resistive shells in two variants of two RFP machines: (1) modification from Reversed Field Experiment (RFX) [Gnesotto et al., Fusion Eng. Des. 25, 335 (1995)] to the modified RFX: both of them are equipped with one thin shell plus one thick shell; (2) modification from Extrap T2 to Extrap T2R [Brunsell et al., Plasma Phys. Controlled Fusion 43, 1457 (2001)]: both of them are equipped with two thin shells. The transient theory has been applied numerically to study the time evolution of the EM torque during the unlocking of a locked tearing mode in the modified RFX

  17. [Optimization and assessment of a reverse hybridization system for the detection of HBV drug-resistant mutations].

    Science.gov (United States)

    Liu, Yan-chen; Huang, Ai-long; Hu, Yuan; Hu, Jie-li; Lai, Guo-qi; Zhang, Wen-lu

    2011-12-01

    To establish a detection method for HBV drug-resistant mutations related to lamivudine, adefovir and entecavir by optimization and assessment of reverse hybridization system. 26 degenerated probes covering 10 drug-resistant hotspots of 3 drugs were synthesized and immobilized on the same positively charged nylon membrane. PCR products labeled with digoxigenin were hybridized with corresponding probes. To improve the sensitivity and specificity, 4 reaction steps of reverse hybridization were optimized including the number of labeled digoxigenin, the energy intensity of UV cross-linking, hybridization and stringency wash conditions. To prove the feasibility, the specificity, sensitivity and accuracy of this system were assessed respectively. Sensitive and specific results are obtained by the optimization of the following 4 reaction steps: the primers labeled with 3 digoxigenin, energy intensity of UV cross-linking for 1500 x 0.1 mJ/cm², hybridization at 42 degrees C and stringency wash with 0.5 x SSC and 0.1% SDS solution at 44 degrees C for 30 min. In the assessment of system, the majority of probes have high specificity. The quantity of PCR product with a concentration of 10 ng/μl or above can be detected by this method. The concordant rate between reverse hybridization and direct sequencing is 93.9% in the clinical sample test. Though the specificity of several probes needs to be improved further, it is a simple, rapid and sensitive method which can detect HBV resistant mutations related to lamivudine, adefovir and entecavir simultaneously. Due to the short distance between 180 and 181, likewise 202 and 204, the sequence of the same probe covers two codon positions, and hybridization will be interfered by each other. To avoid such interference, the possible solution is that probes are designed by arranging and combining various forms of two near codons.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. Novel and Reversible Mechanisms of Smoking-Induced Insulin Resistance in Humans

    OpenAIRE

    Bergman, Bryan C.; Perreault, Leigh; Hunerdosse, Devon; Kerege, Anna; Playdon, Mary; Samek, Ali M.; Eckel, Robert H.

    2012-01-01

    Smoking is the most common cause of preventable morbidity and mortality in the United States, in part because it is an independent risk factor for the development of insulin resistance and type 2 diabetes. However, mechanisms responsible for smoking-induced insulin resistance are unclear. In this study, we found smokers were less insulin sensitive compared with controls, which increased after either 1 or 2 weeks of smoking cessation. Improvements in insulin sensitivity after smoking cessation...

  3. 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.

  4. Reversal of dexamethasone induced insulin resistance in 3T3L1 adipocytes by 3β-taraxerol of Mangifera indica.

    Science.gov (United States)

    Sangeetha, K N; Shilpa, K; Jyothi Kumari, P; Lakshmi, B S

    2013-02-15

    The present study investigates the efficacy of Mangifera indica ethyl acetate extract (MIEE) and its bioactive compound, 3β-taraxerol in the reversal of dexamethasone (DEX) induced insulin resistance in 3T3L1 adipocytes. MIEE and 3β-taraxerol were evaluated for their ability to restore impaired glucose uptake and, expression of molecular markers in the insulin signaling pathway induced by DEX in 3T3L1 adipocytes using 2-deoxy-D-[1-(3)H] glucose uptake assay and ELISA. An insulin resistant model has been developed using a glucocorticoid, DEX on 3T3L1 adipocytes. Insulin resistant condition was observed at 24h of DEX induction wherein a maximum degree of resistance of about 50% was measured based on inhibition of glucose uptake, which was confirmed using cytotoxicity analysis. The developed model of insulin resistance was studied in comparison to positive control rosiglitazone. DEX induced inhibition of glucose uptake and the expression of insulin signaling markers GLUT4 and PI3K were found to be restored by 3β-taraxerol and MIEE, thus delineating its mechanism of action in the reversal of insulin resistance. 3β-Taraxerol effectively restored DEX induced desensitization via restoration of PI3K and GLUT4 expression. To conclude, since 3β-taraxerol exhibits significant effect in reversing insulin resistance it can be further investigated as an insulin resistance reversal agent. Copyright © 2012 Elsevier GmbH. All rights reserved.

  5. Model of 1/f noise in ion implanted resistors as a function of the resistance, determined by a reverse bias voltage

    International Nuclear Information System (INIS)

    Beck, H.G.E.

    1979-01-01

    A model is presented for the 1/f noise in ion-implanted resistors. The resistance was changed by a reverse bias voltage. The model explains the experimentally found square dependence between the relative 1/f noise intensity C/C 0 and the relative change in resistance R/R 0 . (author)

  6. F-Box Protein FBXO22 Mediates Polyubiquitination and Degradation of CD147 to Reverse Cisplatin Resistance of Tumor Cells.

    Science.gov (United States)

    Wu, Bo; Liu, Zhen-Yu; Cui, Jian; Yang, Xiang-Min; Jing, Lin; Zhou, Yang; Chen, Zhi-Nan; Jiang, Jian-Li

    2017-01-20

    Drug resistance remains a major clinical obstacle to successful treatment of cancer. As posttranslational modification is becoming widely recognized to affect the function of oncoproteins, targeting specific posttranslational protein modification provides an attractive strategy for anticancer drug development. CD147 is a transmembrane glycoprotein contributing to chemo-resistance of cancer cells in a variety of human malignancies. Ubiquitination is an important posttranslational modification mediating protein degradation. Degradation of oncoproteins, CD147 included, emerges as an attractive alternative for tumor inhibition. However, the ubiquitination of CD147 remains elusive. Here in this study, we found that deletion of the CD147 intracellular domain (CD147-ICD) prolonged the half-life of CD147 in HEK293T cells, and we identified that CD147-ICD interacts with FBXO22 using mass spectrometry and Western blot. Then, we demonstrated that FBXO22 mediates the polyubiquitination and degradation of CD147 by recognizing CD147-ICD. While knocking down of FBXO22 prolonged the half-life of CD147 in HEK293T cells, we found that FBXO22 regulates CD147 protein turnover in SMMC-7721, Huh-7 and A549 cells. Moreover, we found that the low level of FBXO22 contributes to the accumulation of CD147 and thereafter the cisplatin resistance of A549/DDP cells. To conclude, our study demonstrated that FBXO22 mediated the polyubiquitination and degradation of CD147 by interacting with CD147-ICD, and CD147 polyubiquitination by FBXO22 reversed cisplatin resistance of tumor cells.

  7. Reversal of cisplatin resistance in non-small cell lung cancer stem cells by Taxus chinensis var.

    Science.gov (United States)

    Jiang, Y Q; Xu, X P; Guo, Q M; Xu, X C; Liu, Q Y; An, S H; Xu, J L; Su, F; Tai, J B

    2016-09-02

    Drug resistance in cells is a major impedance to successful treatment of lung cancer. Taxus chinensis var. inhibits the growth of tumor cells and promotes the synthesis of interleukins 1 and 2 and tumor necrosis factor, enhancing immune function. In this study, T. chinensis var.-induced cell death was analyzed in lung cancer cells (H460) enriched for stem cell growth in a defined serum-free medium. Taxus-treated stem cells were also analyzed for Rhodamine 123 (Rh-123) expression by flow cytometry, and used as a standard functional indicator of MDR. The molecular basis of T. chinensis var.-mediated drug resistance was established by real-time PCR analysis of ABCC1, ABCB1, and lung resistance-related protein (LRP) mRNA, and western blot analysis of MRP1, MDR1, and LRP. Our results revealed that stem cells treated with higher doses of T. chinensis var. showed significantly lower growth inhibition rates than did H460 cells (P var. and cisplatin was also significantly inhibited (P var. (P var.-treated stem cells showed significant downregulation of the ABCC1, ABCB1, and LRP mRNA and MRP1, MDR1, and LRP (P var.-mediated downregulation of MRP1, MDR1, and LRP might contribute to the reversal of drug resistance in non-small cell lung cancer stem cells.

  8. Review The Emerging Profile of Cross-Resistance among the Nonnucleoside HIV-1 Reverse Transcriptase Inhibitors

    OpenAIRE

    Nicolas Sluis-Cremer

    2014-01-01

    Nonnucleoside reverse transcriptase inhibitors (NNRTIs) are widely used to treat HIV-1-infected individuals; indeed most first-line antiretroviral therapies typically include one NNRTI in combination with two nucleoside analogs. In 2008, the next-generation NNRTI etravirine was approved for the treatment of HIV-infected antiretroviral therapy-experienced individuals, including those with prior NNRTI exposure. NNRTIs are also increasingly being included in strategies to prevent HIV-1 infectio...

  9. [Molecular mechanism of cisplatin to enhance the ability of TRAIL in reversing multidrug resistance in gastric cancer cells].

    Science.gov (United States)

    Zhu, Xingchao; Zhang, Kaiguang; Wang, Qiaomin; Chen, Si; Gou, Yawen; Cui, Yufang; Li, Qin

    2015-06-01

    To study the molecular mechanism of cisplatin to enhance the ability of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in reversing multidrug resistance in vincristine-resistant human gastric cancer SGC7901/VCR cells. MTT assay was used to measure the 50% inhibiting concentration (IC₅₀) and cell survival in SGC7901 and SGC7901/VCR cells after different treatments. SGC7901/VCR cells were treated with different concentrations of DDP, different concentrations of TRAIL alone or in combination, and then the mRNA and protein levels of several genes were determined by RT-PCR, RT-qPCR and Western-blot analysis. After targeted silencing with specific siRNA and transfection of recombinant plasmid c-myc into the SGC7901/VCR cells, the mRNA and protein levels of DR4, DR5 and c-myc were determined by RT-PCR and Western-blot analysis. After combined treatment with TRAIL and DDP of the SGC7901/VCR cells, the IC₅₀ of VCR, DDP, ADM, and 5-Fu treatment was significantly decreased compared with the control group or TRAIL-treated group (P mechanism of DDP-induced sensitization of TRAIL to reverse the multidrug resistancein SGC7901/VCR cells.

  10. Physical understanding of the instability spectrum and the feedback control of resistive wall modes in reversed field pinch

    International Nuclear Information System (INIS)

    Wang, Z.R.; Guo, S.C.

    2011-01-01

    The cylindrical MHD model integrated with a feedback system is applied to the study of resistive wall mode (RWM) in reversed field pinch (RFP) plasmas. The model takes into account the compressibility, longitudinal flow, viscosity and resistive wall with a finite thickness. The study, via both analytical and numerical analyses, provides a physical understanding on the following subjects: firstly, on the nature of the instability spectrum of the RWM observed in RFP plasmas; specifically, the growth rates of the two groups of the RWMs (internally non-resonant and externally non-resonant) have opposite dependence on the variation of the field reversal. Secondly, on the response of the unstable plasmas to the feedback control in RFPs, the mode behaviour in plasmas under the feedback is clarified and discussed in detail. Finally, the linear solutions of time evolution of RWM instability in various feedback scenarios are given. The effects of the wall proximity, the sensor location and the system response time are discussed, respectively.

  11. Ultra-low q and reversed field pinch experiments in Extrap T1 with a resistive shell

    International Nuclear Information System (INIS)

    Brunsell, P.; Drake, J.R.; Mazur, S.; Nordlund, P.

    1991-02-01

    The Extrap T1 device is a high aspect ratio toroidal pinch with the dimensions R/a = 0.5 m/0.057 m. In the experiments described here, the stainless steel bellows vacuum vessels was surrounded by a resistive shell with a perpendicular field penetration time of 75 μs. The ULQ discharges, with toroidal currents in the range 20-50 kA and pulse lengths up to 2 ms, showed the typical step-wise decay of the plasma current. The current steps corresponded to transitions of the edge q-value across rational values 1/4, 1/3, 1/2, and 1. During a step through a rational q value, there was an increase in the fluctuation activity and a corresponding increase in the plasma resistance. As part of the ULQ studies, discharges with four poloidal field nulls were produced by applying an octupole magnetic field, thus demonstrating that it is possible to sustain ULQ equilibria with poloidal field x-points and a magnetic separatix. In another study, the transition from ULQ discharges to relaxed state discharges was investigated. When the initial bias toroidal field was reduced so that q was less than about 1/6, which corresponded to a pinch parameter of about 0.6, a change in the discharge character was observed. The loop voltage required to sustain a given current increased and stochastic fluctuations were seen. Toroidal flux was generated and relaxed state equilibira developed. For higher pinch parameter, in the range of 1.5 to 2.0, a reversed field pinch could be set up if the toroidal field power supply provided a reversed current in the coils. The plasma resistivity was again lower and the pulse lengths in the RFP mode were up to 1 ms, corresponding to over 10 shell penetration times. (au)

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

    Czech Academy of Sciences Publication Activity Database

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

    2014-01-01

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

  13. Doxorubicin-induced second degree and complete atrioventricular block.

    Science.gov (United States)

    Kilickap, Saadettin; Akgul, Ebru; Aksoy, Sercan; Aytemir, Kudret; Barista, Ibrahim

    2005-05-01

    Doxorubicin is one of the most effective chemotherapeutic agents used in the treatment of malignancies. Cardiotoxicity is the most important dose-limiting toxicity of doxorubicin. Although cardiomyopathy is the most well known side effect of doxorubicin, it usually occurs many years after the treatment and relates to cumulative doxorubicin dosage. Another form of doxorubicin cardiotoxicity is arrhythmia which may occur at any time and after any dosage. However, doxorubicin-induced arrhythmia is rarely a life-threatening side effect. In this report, we present a case in which there were doxorubicin-induced life-threatening arrhythmias.

  14. 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

  15. Nanohybrid systems of non-ionic surfactant inserting liposomes loading paclitaxel for reversal of multidrug resistance.

    Science.gov (United States)

    Ji, Xiufeng; Gao, Yu; Chen, Lingli; Zhang, Zhiwen; Deng, Yihui; Li, Yaping

    2012-01-17

    Three new nanohybrid systems of non-ionic surfactant inserting liposomes loading paclitaxel (PTX) (NLPs) were prepared to overcome multidrug resistance (MDR) in PTX-resistance human lung cancer cell line. Three non-ionic surfactants, Solutol HS 15 (HS-15), pluronic F68 (PF-68) and cremophor EL (CrEL) were inserted into liposomes by film hydration method to form NLPs with an average size of around 110, 180 and 110 nm, respectively. There was an obvious increase of rhodamin 123 (Rh123) accumulation in A549/T cells after treated with nanohybrid systems loading Rh123 (NLRs) when compared with free Rh123 or liposomes loading Rh123 without surfactants (LRs), which indicated the significant inhibition effects of NLRs on drug efflux. The P-gp detection and ATP determination demonstrated that BNLs could not only interfere P-gp expression on the membrane of drug resistant cells, but also decrease ATP level in the cells. The cytotoxicity of NLPs against A549/T cells was higher than PTX loaded liposomes without surfactants (LPs), and the best result was achieved after treated with NLPs2. The apoptotic assay and the cell cycle analysis showed that NLPs could induce more apoptotic cells in drug resistant cells when compared with LPs. These results suggested that NLPs could overcome MDR by combination of drug delivery, P-gp inhibition and ATP depletion, and showed potential for treatment of MDR. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. 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

  17. 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

  18. Reversal of fluconazole resistance induced by a synergistic effect with Acca sellowiana in Candida glabrata strains.

    Science.gov (United States)

    R M Machado, Gabriella da; Pippi, Bruna; Dalla Lana, Daiane Flores; Amaral, Ana Paula S; Teixeira, Mário Lettieri; Souza, Kellen C B de; Fuentefria, Alexandre M

    2016-11-01

    The increased incidence of non-albicans Candida (NAC) resistant to fluconazole (FLZ) makes it necessary to use new therapeutic alternatives. Acca sellowiana (O.berg) Burret (Myrtaceae) is a guava with several proven biological activities. The interaction with fluconazole can be a feasible alternative to overcome this resistance. This study evaluates the in vitro antifungal activity of fractions obtained from the lyophilized aqueous extract of the leaves of A. sellowiana against resistant strains of NAC. The antifungal activity of the fractions was evaluated at 500 μg/mL by microdilution method. Checkerboard assay was performed to determine the effect of the combination of the F2 fraction and antifungal at concentrations: MIC/4, MIC/2, MIC, MIC × 2 and MIC × 4. Candida glabrata showed the lowest MIC values (500-3.90 μg/mL) and the F2 active fraction was the most effective. The association of F2 with FLZ showed a strong synergistic effect (FICI ≤ 0.5) against 100% of C. glabrata resistant isolates. Moreover, the F2 active fraction has demonstrated that probably acts in the cell wall of these yeasts. There was no observed acute dermal toxicity of lyophilized aqueous extract of leaves of A. sellowiana on pig ear skin cells. The interaction between substances present in the F2 active fraction is possibly responsible for the antifungal activity presented by this fraction. This study is unprecedented and suggests that the combination of F2 active fraction and FLZ might be used as an alternative treatment for mucocutaneus infections caused by C. glabrata resistant.

  19. Reversible Changes in Resistance of Perovskite Nickelate NdNiO3 Thin 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.

  20. Reversion of High-level Mecillinam Resistance to Susceptibility in Escherichia coli During Growth in Urine

    Directory of Open Access Journals (Sweden)

    Elisabeth Thulin

    2017-09-01

    This is the first example describing conditional resistance where a genetically stable antibiotic resistance can be phenotypically reverted to susceptibility by metabolites present in urine. These findings have several important clinical implications regarding the use of mecillinam to treat UTIs. First, they suggest that mecillinam can be used to treat also those clinical strains that are identified as MecR in standard laboratory tests. Second, the results suggest that testing of mecillinam susceptibility in the laboratory ought to be performed in media that mimics urine to obtain clinically relevant susceptibility testing results. Third, these findings imply that changes in patient behavior, such as increased water intake or use of diuretics to reduce urine osmolality and increased intake of cysteine, might induce antibiotic susceptibility in an infecting MecR E. coli strain and thereby increase treatment efficiency.

  1. Reversible Dissolution of Microdomains in Detergent-Resistant Membranes at Physiological Temperature

    OpenAIRE

    Cremona, A.; Orsini, F.; Corsetto, P.A.; Hoogenboom, B.W.; Rizzo, A.M.

    2015-01-01

    The formation of lipid microdomains ("rafts") is presumed to play an important role in various cellular functions, but their nature remains controversial. Here we report on microdomain formation in isolated, detergent-resistant membranes from MDA-MB-231 human breast cancer cells, studied by atomic force microscopy (AFM). Whereas microdomains were readily observed at room temperature, they shrunk in size and mostly disappeared at higher temperatures. This shrinking in microdomain size was acco...

  2. 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

  3. F-Box Protein FBXO22 Mediates Polyubiquitination and Degradation of CD147 to Reverse Cisplatin Resistance of Tumor Cells

    Directory of Open Access Journals (Sweden)

    Bo Wu

    2017-01-01

    Full Text Available Drug resistance remains a major clinical obstacle to successful treatment of cancer. As posttranslational modification is becoming widely recognized to affect the function of oncoproteins, targeting specific posttranslational protein modification provides an attractive strategy for anticancer drug development. CD147 is a transmembrane glycoprotein contributing to chemo-resistance of cancer cells in a variety of human malignancies. Ubiquitination is an important posttranslational modification mediating protein degradation. Degradation of oncoproteins, CD147 included, emerges as an attractive alternative for tumor inhibition. However, the ubiquitination of CD147 remains elusive. Here in this study, we found that deletion of the CD147 intracellular domain (CD147-ICD prolonged the half-life of CD147 in HEK293T cells, and we identified that CD147-ICD interacts with FBXO22 using mass spectrometry and Western blot. Then, we demonstrated that FBXO22 mediates the polyubiquitination and degradation of CD147 by recognizing CD147-ICD. While knocking down of FBXO22 prolonged the half-life of CD147 in HEK293T cells, we found that FBXO22 regulates CD147 protein turnover in SMMC-7721, Huh-7 and A549 cells. Moreover, we found that the low level of FBXO22 contributes to the accumulation of CD147 and thereafter the cisplatin resistance of A549/DDP cells. To conclude, our study demonstrated that FBXO22 mediated the polyubiquitination and degradation of CD147 by interacting with CD147-ICD, and CD147 polyubiquitination by FBXO22 reversed cisplatin resistance of tumor cells.

  4. In Vitro Cross-Resistance Profiles of Rilpivirine, Dapivirine, and MIV-150, Nonnucleoside Reverse Transcriptase Inhibitor Microbicides in Clinical Development for the Prevention of HIV-1 Infection.

    Science.gov (United States)

    Giacobbi, Nicholas S; Sluis-Cremer, Nicolas

    2017-07-01

    Rilpivirine (RPV), dapivirine (DPV), and MIV-150 are in development as microbicides. It is not known whether they will block infection of circulating nonnucleoside reverse transcriptase inhibitor (NNRTI)-resistant human immunodeficiency virus type 1 (HIV-1) variants. Here, we demonstrate that the activity of DPV and MIV-150 is compromised by many resistant viruses containing single or double substitutions. High DPV genital tract concentrations from DPV ring use may block replication of resistant viruses. However, MIV-150 genital tract concentrations may be insufficient to inhibit many resistant viruses, including those harboring K103N or Y181C. Copyright © 2017 American Society for Microbiology.

  5. Reversing resistance to vascular-disrupting agents by blocking late mobilization of circulating endothelial progenitor cells.

    Science.gov (United States)

    Taylor, Melissa; Billiot, Fanny; Marty, Virginie; Rouffiac, Valérie; Cohen, Patrick; Tournay, Elodie; Opolon, Paule; Louache, Fawzia; Vassal, Gilles; Laplace-Builhé, Corinne; Vielh, Philippe; Soria, Jean-Charles; Farace, Françoise

    2012-05-01

    The prevailing concept is that immediate mobilization of bone marrow-derived circulating endothelial progenitor cells (CEP) is a key mechanism mediating tumor resistance to vascular-disrupting agents (VDA). Here, we show that administration of VDA to tumor-bearing mice induces 2 distinct peaks in CEPs: an early, unspecific CEP efflux followed by a late yet more dramatic tumor-specific CEP burst that infiltrates tumors and is recruited to vessels. Combination with antiangiogenic drugs could not disrupt the early peak but completely abrogated the late VDA-induced CEP burst, blunted bone marrow-derived cell recruitment to tumors, and resulted in striking antitumor efficacy, indicating that the late CEP burst might be crucial to tumor recovery after VDA therapy. CEP and circulating endothelial cell kinetics in VDA-treated patients with cancer were remarkably consistent with our preclinical data. These findings expand the current understanding of vasculogenic "rebounds" that may be targeted to improve VDA-based strategies. Our findings suggest that resistance to VDA therapy may be strongly mediated by late, rather than early, tumor-specific recruitment of CEPs, the suppression of which resulted in increased VDA-mediated antitumor efficacy. VDA-based therapy might thus be significantly enhanced by combination strategies targeting late CEP mobilization. © 2012 AACR

  6. Early and late arrhythmogenic effects of doxorubicin.

    Science.gov (United States)

    Kilickap, Saadettin; Barista, Ibrahim; Akgul, Ebru; Aytemir, Kudret; Aksoy, Sercan; Tekuzman, Gulten

    2007-03-01

    To determine the incidence of early and late arrhythmogenic effects of doxorubicin-containing chemotherapy regimens. A prospective study including 29 patients who were treated with doxorubicin-containing regimens. Cardiac evaluation was based on 24-hour electrocardiographic monitorization (Holter), which was performed during the first cycle of doxorubicin-containing regimens, as well as after the last cycle of chemotherapy. The mean age of the patients was 45.8 +/- 15.1 (range 18-69). Holter records obtained during the first cycle of treatment revealed varying arrhythmias in 19 patients (65.5%) and in 18 (62.1%) patients after completion of therapy. One patient presented with syncope and both Mobitz Type 2 atrioventricular block and complete atrioventricular block were demonstrated. The patient subsequently underwent permanent pacemaker implantation. Doxorubicin may result in arrhythmias both in early and late periods of treatment. These arrhythmias are rarely life threatening.

  7. Biodegradable mixed MPEG-SS-2SA/TPGS micelles for triggered intracellular release of paclitaxel and reversing multidrug resistance

    Directory of Open Access Journals (Sweden)

    Dong K

    2016-10-01

    Full Text Available Kai Dong,1 Yan Yan,2 Pengchong Wang,2 Xianpeng Shi,2 Lu Zhang,2 Ke Wang,2 Jianfeng Xing,2 Yalin Dong1 1Department of Pharmacy, The First Affiliated Hospital of Xi’an Jiaotong University, 2School of Pharmacy, Xi’an Jiaotong University, Xi’an, Shaanxi, People’s Republic of China Abstract: In this study, a type of multifunctional mixed micelles were prepared by a novel biodegradable amphiphilic polymer (MPEG-SS-2SA and a multidrug resistance (MDR reversal agent (D-α-tocopheryl polyethylene glycol succinate, TPGS. The mixed micelles could achieve rapid intracellular drug release and reversal of MDR. First, the amphiphilic polymer, MPEG-SS-2SA, was synthesized through disulfide bonds between poly (ethylene glycol monomethyl ether (MPEG and stearic acid (SA. The structure of the obtained polymer was similar to poly (ethylene glycol-phosphatidylethanolamine (PEG-PE. Then the mixed micelles, MPEG-SS-2SA/TPGS, were prepared by MPEG-SS-2SA and TPGS through the thin film hydration method and loaded paclitaxel (PTX as the model drug. The in vitro release study revealed that the mixed micelles could rapidly release PTX within 24 h under a reductive environment because of the breaking of disulfide bonds. In cell experiments, the mixed micelles significantly inhibited the activity of mitochondrial respiratory complex II, also reduced the mitochondrial membrane potential, and the content of adenosine triphosphate, thus effectively inhibiting the efflux of PTX from cells. Moreover, in the confocal laser scanning microscopy, cellular uptake and 3-(4,5-dimethyl-thiazol-2-yl-2,5-diphenyl-tetrazolium bromide assays, the MPEG-SS-2SA/TPGS micelles achieved faster release and more uptake of PTX in Michigan Cancer Foundation-7/PTX cells and showed better antitumor effects as compared with the insensitive control. In conclusion, the biodegradable mixed micelles, MPEG-SS-2SA/TPGS, could be potential vehicles for delivering hydrophobic chemotherapeutic drugs in

  8. Effects of quercetin on kidney injury induced by doxorubicin.

    Science.gov (United States)

    Yagmurca, M; Yasar, Z; Bas, O

    2015-01-01

    The anthracycline antitumor drug doxorubicine causes severe nephrotoxicity in a variety of experimental animals and may be nephrotoxic to humans. The aim of present study was to determine the protective effects of quercetin against doxorubicin-induced kidney injury with light microscopy. Forty male Wistar albino rats were divided into four groups: control, doxorubicin, doxorubicin+quercetin and quercetin. A single dose of 20 mg/kg/ i.p. doxorubicin was used to induce injury. Quercetin was administrated orally against doxorubicin toxicity. The kidneys were examined under light microscopy after H-E (hematoxylin-eosin) staining and the changes were scored. Significant tissue injury was observed in doxorubicin-administered group. Among these injuries, renal tubular dilatation, tubular vacuolar changes, glomerular vacuolization, decrease in bowman space, bowman capsule thickening, and interstitial infiltration were evident. However, the injury induced by doxorubicin was attenuated with quercetin administration. Quercetin decreased doxorubicin-induced kidney damage (Tab. 1, Fig. 4, Ref. 27).

  9. Two-fluid and nonlinear effects of tearing and pressure-driven resistive modes in reversed field pinches

    International Nuclear Information System (INIS)

    Mirnov, V.V.

    2002-01-01

    Large-scale tearing instabilities have long been considered to underlie transport and dynamo processes in the reversed field pinch (RFP). The vast majority of theoretical and computational RFP work has focused on pressureless, single-fluid MHD in cylindrical plasmas driven solely by a toroidal electric field. We report results of five investigations covering two-fluid dynamos, toroidal nonlinear MHD computation, nonlinear computation of Oscillating Field Current Drive (OFCD), the effect of shear flow on tearing instability, and the effect of pressure on resistive instability. The key findings are: (1) two-fluid dynamo arising from the Hall term is much larger than the standard MHD dynamo present in a single-fluid treatment, (2) geometric coupling from toroidicity precludes the occurrence of laminar single helicity states, except for nonreversed plasmas, (3) OFCD, a form of AC helicity injection, can sustain the RFP plasma current, although magnetic fluctuations are enhanced, (4) edge shear flow can destabilize the edge resonant m=0 modes, which occur as spikes in experiment, and (5) pressure driven modes are resistive at low beta, only becoming ideal at extremely high beta. (author)

  10. [Effect of silencing Bmi-1 expression in reversing cisplatin resistance in lung cancer cells and its mechanism].

    Science.gov (United States)

    Mao, Nan; He, Guansheng; Rao, Jinjun; Lv, Lin

    2014-06-01

    To investigate the effect of silencing Bmi-1 expression in reversing cisplatin resistance in human lung cancer cells and explore the possible mechanisms. Cisplatin-resistant A549/DDP cells with small interference RNA (siRNA)-mediated Bmi-1 expression silencing were examined for cisplatin sensitivity using MTT assay and alterations in cell cycle distribution and apoptosis with flow cytometry, and the changes in cell senescence was assessed using β-galactosidase staining. The protein expressions of Bmi-1, P14(ARF), P16(INK4a), P53, P21, Rb and ubi-H2AK119 in the cells were determined with Western blotting. A549/DDP cells showed significantly higher Bmi-1 expression than A549 cells. After siRNA-mediated Bmi-1 silencing, A549/DDP cells showed significantly enhanced cisplatin sensitivity with an increased IC50 from 40.3±4.1 µmol/L to 18.3±2.8 µmol/L (Pcisplatin possibly by regulating INK4a/ARF/Rb senescence pathway.

  11. 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.

  12. S-diclofenac Protects against Doxorubicin-Induced Cardiomyopathy in Mice via Ameliorating Cardiac Gap Junction Remodeling

    Science.gov (United States)

    Zhang, Huili; Zhang, Alian; Guo, Changfa; Shi, Chunzhi; Zhang, Yang; Liu, Qing; Sparatore, Anna; Wang, Changqian

    2011-01-01

    Hydrogen sulfide (H2S), 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-dichlorophenyl)amino] benzeneacetic acid 4-(3H-1,2,dithiol-3-thione-5-yl)phenyl ester), a novel H2S-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 H2S 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 H2S in the pathogenesis of doxorubicin-induced cardiomyopathy. PMID:22039489

  13. 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.

  14. 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.

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

    International Nuclear Information System (INIS)

    Dave, V.; Rao, G. P.; Tiwari, G. S.; Sanger, A.; Kumar, A.; Chandra, R.

    2016-01-01

    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.

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

    Science.gov (United States)

    Dave, V.; Rao, G. P.; Tiwari, G. S.; Sanger, A.; Kumar, A.; Chandra, R.

    2016-04-01

    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.

  17. Can high-dose fotemustine reverse MGMT resistance in glioblastoma multiforme?

    Science.gov (United States)

    Gallo, Chiara; Buonerba, Carlo; Di Lorenzo, Giuseppe; Romeo, Valeria; De Placido, Sabino; Marinelli, Alfredo

    2010-11-01

    Glioblastoma multiforme (GBM), the highest grade malignant glioma, is associated with a grim prognosis-median overall survival is in the range 12-15 months, despite optimum treatment. Surgery to the maximum possible extent, external beam radiotherapy, and systemic temozolomide chemotherapy are current standard treatments for newly diagnosed GBM, with intracerebral delivery of carmustine wafers (Gliadel). Unfortunately, the effectiveness of chemotherapy can be hampered by the DNA repair enzyme O6-methylguanine methyltransferase (MGMT), which confers resistance both to temozolomide and nitrosoureas, for example fotemustine and carmustine. MGMT activity can be measured by PCR and immunohistochemistry, with the former being the current validated technique. High-dose chemotherapy can deplete MGMT levels in GBM cells and has proved feasible in various trials on temozolomide, in both newly diagnosed and recurrent GBM. We here report the unique case of a GBM patient, with high MGMT expression by immunohistochemistry, who underwent an experimental, high-dose fotemustine schedule after surgery and radiotherapy. Although treatment caused two episodes of grade 3-4 thrombocytopenia, a complete response and survival of more than three years were achieved, with a 30% increase in dose intensity compared with the standard fotemustine schedule.

  18. Thermo-sensitive liposomes loaded with doxorubicin and lysine modified single-walled carbon nanotubes as tumor-targeting drug delivery system.

    Science.gov (United States)

    Zhu, Xiali; Xie, Yingxia; Zhang, Yingjie; Huang, Heqing; Huang, Shengnan; Hou, Lin; Zhang, Huijuan; Li, Zhi; Shi, Jinjin; Zhang, Zhenzhong

    2014-11-01

    This report focuses on the thermo-sensitive liposomes loaded with doxorubicin and lysine-modified single-walled carbon nanotube drug delivery system, which was designed to enhance the anti-tumor effect and reduce the side effects of doxorubicin. Doxorubicin-lysine/single-walled carbon nanotube-thermo-sensitive liposomes was prepared by reverse-phase evaporation method, the mean particle size was 232.0 ± 5.6 nm, and drug entrapment efficiency was 86.5 ± 3.7%. The drug release test showed that doxorubicin released more quickly at 42℃ than at 37℃. Compared with free doxorubicin, doxorubicin-lysine/single-walled carbon nanotube-thermo-sensitive liposomes could efficiently cross the cell membranes and afford higher anti-tumor efficacy on the human hepatic carcinoma cell line (SMMC-7721) cells in vitro. For in vivo experiments, the relative tumor volumes of the sarcomaia 180-bearing mice in thermo-sensitive liposomes group and doxorubicin group were significantly smaller than those of N.S. group. Meanwhile, the combination of near-infrared laser irradiation at 808 nm significantly enhanced the tumor growth inhibition both on SMMC-7721 cells and the sarcomaia 180-bearing mice. The quality of life such as body weight, mental state, food and water intake of sarcomaia 180 tumor-bearing mice treated with doxorubicin-lysine/single-walled carbon nanotube-thermo-sensitive liposomes were much higher than those treated with doxorubicin. In conclusion, doxorubicin-lysine/single-walled carbon nanotube-thermo-sensitive liposomes combined with near-infrared laser irradiation at 808 nm may potentially provide viable clinical strategies for targeting delivery of anti-cancer drugs. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  19. Treatment with low-dose resveratrol reverses cardiac impairment in obese prone but not in obese resistant rats.

    Science.gov (United States)

    Louis, Xavier L; Thandapilly, Sijo J; MohanKumar, Suresh K; Yu, Liping; Taylor, Carla G; Zahradka, Peter; Netticadan, Thomas

    2012-09-01

    We hypothesized that a low-dose resveratrol will reverse cardiovascular abnormalities in rats fed a high-fat (HF) diet. Obese prone (OP) and obese resistant (OR) rats were fed an HF diet for 17 weeks; Sprague-Dawley rats fed laboratory chow served as control animals. During the last 5 weeks of study, treatment group received resveratrol daily by oral gavage at a dosage of 2.5 mg/kg body weight. Assessments included echocardiography, blood pressure, adiposity, glycemia, insulinemia, lipidemia, and inflammatory and oxidative stress markers. Body weight and adiposity were significantly higher in OP rats when compared to OR rats. Echocardiographic measurements showed prolonged isovolumic relaxation time in HF-fed OP and OR rats. Treatment with resveratrol significantly improved diastolic function in OP but not in OR rats without affecting adiposity. OP and OR rats had increased blood pressure which remained unchanged with treatment. OP rats had elevated fasting serum glucose and insulin, whereas OR rats had increased serum glucose and normal insulin concentrations. Resveratrol treatment significantly reduced serum glucose while increasing serum insulin in both OP and OR rats. Inflammatory and oxidative stress markers, serum triglycerides and low-density lipoprotein were higher in OP rats, which were significantly reduced with treatment. In conclusion, HF induced cardiac dysfunction in both OP and OR rats. Treatment reversed abnormalities in diastolic heart function associated with HF feeding in OP rats, but not in OR rats. The beneficial effects of resveratrol may be mediated through regression of hyperglycemia, oxidative stress and inflammation. Copyright © 2012 Elsevier Inc. All rights reserved.

  20. 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.

  1. LDR reverses DDP resistance in ovarian cancer cells by affecting ERCC-1, Bcl-2, Survivin and Caspase-3 expressions.

    Science.gov (United States)

    Ju, Xingyan; Yu, Hongsheng; Liang, Donghai; Jiang, Tao; Liu, Yuanwei; Chen, Ling; Dong, Qing; Liu, Xiaoran

    2018-06-01

    Ovarian cancer is the most frequent cause of death resulting from malignant gynecological tumors. After surgical intervention, cisplatin (DDP) is a major chemotherapy drug for ovarian cancer, but the ovarian cancer cells tend to develop DDP resistance in the clinical setting. Tumor cells are sensitive to low-dose radiation (LDR). However, how the LDR therapy improves the effects of chemotherapy drugs on ovarian cancer is not well understood. This study aimed to explore this issue. The SKOV3/DDP cells were divided into 3 groups, including low-dose group, conventional-dose group, and control group (no radiation). Cell counting kit-8 assay was performed to measure cell proliferation. Flow cytometric analysis was then utilized to quantify the apoptosis with classical Annexin V/propidium iodide co-staining. And Real-time quantitative PCR and western blot were eventually used to analyze the mRNA and protein levels of excision repair cross complementing-group 1 (ERCC1), B-cell lymphoma 2 (Bcl-2), Survivin and Caspase-3, respectively. The IC50 value of DDP in the low-dose group was significantly lower compared with the other two groups. Compared with the conventional-dose group and control group, LDR treatment resulted in significantly more apoptosis. Besides, LDR treatment significantly decreased the mRNA and protein expression of ERCC1, Bcl-2, and Survivin, and enhanced the mRNA and protein expression of Caspase-3 compared with the other two groups. LDR reversed DDP resistance in SKOV3/DDP cells possibly by suppressing ERCC1, Bcl-2, and Survivin expressions, and increasing Caspase-3 expression. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  2. 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.

  3. Potentiation of apoptosis by histone deacetylase inhibitors and doxorubicin combination: cytoplasmic cathepsin B as a mediator of apoptosis in multiple myeloma.

    Science.gov (United States)

    Cheriyath, V; Kuhns, M A; Kalaycio, M E; Borden, E C

    2011-03-15

    Although inhibitors of histone deacetylase inhibitors (HDACis) in combination with genotoxins potentiate apoptosis, the role of proteases other than caspases in this process remained elusive. Therefore, we examined the potentiation of apoptosis and related mechanisms of HDACis and doxorubicin combination in a panel of myeloma cell lines and in 25 primary myelomas. At IC(50) concentrations, sodium butyrate (an HDACi) or doxorubicin alone caused little apoptosis. However, their combination potentiated apoptosis and synergistically reduced the viability of myeloma cells independent of p53 and caspase 3-7 activation. Potentiated apoptosis correlated with nuclear translocation of apoptosis-inducing factor, suggesting the induction of caspase 3- and 7-independent pathways. Consistent with this, butyrate and doxorubicin combination significantly increased the activity of cytoplasmic cathepsin B. Inhibition of cathepsin B either with a small-molecule inhibitor or downregulation with a siRNA reversed butyrate- and doxorubicin-potentiated apoptosis. Finally, ex vivo, clinically relevant concentrations of butyrate or SAHA (suberoylanilide hydroxamic acid, vorinostat, an HDACi in clinical testing) in combination with doxorubicin significantly (Pmediating apoptosis potentiated by HDACi and doxorubicin combinations in myeloma. Our results support a molecular model of lysosomal-mitochondrial crosstalk in HDACi- and doxorubicin-potentiated apoptosis through the activation of cathepsin B.

  4. Doxorubicin-anti-carcinoembryonic antigen immunoconjugate activity in vitro.

    Science.gov (United States)

    Richardson, V J; Ford, C H; Tsaltas, G; Gallant, M E

    1989-04-01

    An in vitro model consisting of a series of 11 human cancer cell lines with varying density of expression of membrane carcinoembryonic antigen (CEA) has been used to evaluate conjugates of doxorubicin (Adriamycin) covalently linked by a carbodiimide method to goat polyclonal antibodies and mouse monoclonal antibodies to CEA. Conjugates were produced which retained both antigen binding and drug cytotoxicity. IC50 values were determined for free drug, free drug mixed with unconjugated antibodies and for the immunoconjugates. Cell lines that were very sensitive to free drug (IC50 less than 100 ng/ml) were also found to be highly sensitive to conjugated drug and similarly cell lines resistant to drug (IC50 greater than 1,000 ng/ml) were also resistant to conjugated drug. Although there was no correlation between CEA expression and conjugates efficacy, competitive inhibition studies using autologous antibody to block conjugate binding to cells indicated immunoconjugates specificity for the CEA target.

  5. Tripeptide tyroserleutide plus doxorubicin: therapeutic synergy and side effect attenuation

    International Nuclear Information System (INIS)

    Zhu, Zhi-feng; Yao, Zhi; Chen, Li-juan; Lu, Rong; Jia, Jing; Liang, Yu; Xu, Qiong; Zhou, Chun-lei; Wang, Li; Wang, Song

    2008-01-01

    Tripeptide tyroserleutide (YSL) is a novel small molecule anti-tumor polypeptide that has been shown to inhibit the growth of human liver cancer cells. In this study, we investigated the effects of YSL plus doxorubicin on the growth of human hepatocellular carcinoma BEL-7402 cells that had been transplanted into nude mice. Nude mice bearing human hepatocellular carcinoma BEL-7402 tumors were treated with successive intraperitoneal injections of saline; low-, mid-, or high-dose doxorubicin; or low-, mid-, or high-dose doxorubicin plus YSL. Effects on the weight and volume of the tumors were evaluated. Co-administration of YSL and high-dose doxorubicin (6 mg/kg every other day) prolonged the survival time of tumor-bearing mice as compared to high-dose doxorubicin alone. As well, the anti-tumor effects of mid- and low-dose doxorubicin (2 and 0.7 mg/kg every other day, respectively) were enhanced when supplemented with YSL; the tumor growth inhibition rates for YSL plus doxorubicin were greater than the inhibition rates for the same dosages of doxorubicin alone. The combination of YSL and doxorubicin decreased chemotherapy-associated weight loss, leukocyte depression, and heart, liver, and kidney damage as compared to doxorubicin alone. The combination of YSL plus doxorubicin enhances the anti-tumor effect and reduces the side effects associated with doxorubicin chemotherapy

  6. 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

  7. 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.

  8. Reverse resistance to radiation in KYSE-150R esophageal carcinoma cell after epidermal growth factor receptor signal pathway inhibition by cetuximab

    International Nuclear Information System (INIS)

    Jing Zhao; Gong Ling; Xie Congying; Zhang Li; Su Huafang; Deng Xia; Wu Shixiu

    2009-01-01

    Background and purpose: The purpose of our study is to examine the capacity of cetuximab to reverse radiation resistance and investigate molecular mechanisms in human radiation-resistant esophageal carcinoma cell line KYSE-150R. Materials and methods: The radioresistant cell line KYSE-150R was established by using fractionated irradiation (FIR). The KYSE-150R cell line was exposed to radiation, treatment with cetuximab, and combined treatment. Cell cycle distribution and apoptosis were analyzed using flow cytometry. Radiation survival was analyzed using clonogenic assays. RT 2 profiler TM PCR array was performed to analyze EGF/PDGF signaling pathway genes. Results: The established esophageal carcinoma cell line KYSE-150R showed higher radioresistance than parental cell line. Cetuximab could reverse the radiation resistance of KYSE-150R cells. Cell cycle analysis showed that combination with radiation and cetuximab resulted in the accumulation of cells in G1 and G2/M phases, with the reduction of cells within the S phase. Cetuximab enhanced the apoptosis induced by radiation. RT 2 profiler TM array showed that some intracellular signaling genes deriving from EGF/PDGF signaling pathway regulated by cetuximab. Conclusions: Irradiation combined with EGFR blocked by cetuximab may reverse the resistance to radiation in radioresistant esophageal carcinoma cell. The mechanisms may include cell cycle perturbation and enhancement of radiation-induced apoptosis. Further studies are needed to evaluate the role of cetuximab in combination with radiotherapy in the management of esophageal carcinoma.

  9. Comparative cytotoxicity of gold-doxorubicin and InP-doxorubicin conjugates.

    Science.gov (United States)

    Zhang, Xuan; Chibli, Hicham; Kong, Dekun; Nadeau, Jay

    2012-07-11

    Direct comparisons of different types of nanoparticles for drug delivery have seldom been performed. In this study we compare the physical properties and cellular activity of doxorubicin (Dox) conjugates to gold nanoparticles (Au) and InP quantum dots of comparable diameter. Although the Au particles alone are non-toxic and InP is moderately toxic, Au-Dox is more effective than InP-Dox against the Dox-resistant B16 melanoma cell line. Light exposure does not augment the efficacy of InP-Dox, suggesting that conjugates are breaking down. Electron and confocal microscopy and atomic absorption spectroscopy reveal that over 60% of the Au-Dox conjugates reach the cell nucleus. In contrast, InP-Dox enters cell nuclei to a very limited extent, although liberated Dox from the conjugates does eventually reach the nucleus. These observations are attributed to faster Dox release from Au conjugates under endosomal conditions, greater aggregation of InP-Dox with cytoplasmic proteins, and adherence of InP to membranes. These findings have important implications for design of active drug-nanoparticle conjugates.

  10. Effects of cytochalasin congeners, microtubule-directed agents, and doxorubicin alone or in combination against human ovarian carcinoma cell lines in vitro

    International Nuclear Information System (INIS)

    Trendowski, Matthew; Christen, Timothy D.; Acquafondata, Christopher; Fondy, Thomas P.

    2015-01-01

    Although the actin cytoskeleton is vital for carcinogenesis and subsequent pathology, no microfilament-directed agent has been approved for cancer chemotherapy. One of the most studied classes of microfilament-directed agents has been the cytochalasins, mycotoxins known to disrupt the formation of actin polymers. In the present study, we sought to determine the effects of cytochalasin congeners toward human drug sensitive and multidrug resistant cell lines. SKOV3 human ovarian carcinoma and several multidrug resistant derivatives were tested for sensitivity against a panel of nine cytochalasin congeners, as well as three clinically approved chemotherapeutic agents (doxorubicin, paclitaxel, and vinblastine). In addition, verapamil, a calcium ion channel blocker known to reverse P-glycoprotein (P-gp) mediated drug resistance, was used in combination with multiple cytochalasin congeners to determine whether drug sensitivity could be increased. While multidrug resistant SKVLB1 had increased drug tolerance (was more resistant) to most cytochalasin congeners in comparison to drug sensitive SKOV3, the level of resistance was 10 to 1000-fold less for the cytochalasins than for any of the clinically approved agents. While cytochalasins did not appear to alter the expression of ATP binding cassette (ABC) transporters, several cytochalasins appeared to inhibit the activity of ABC transporter-mediated efflux of rhodamine 123 (Rh123), suggesting that these congeners do have affinity for drug efflux pumps. Cytochalasins also appeared to significantly decrease the F/G-actin ratio in both drug sensitive and drug resistant cells, indicative of marked microfilament inhibition. The cytotoxicity of most cytochalasin congeners could be increased with the addition of verapamil, and the drug sensitivity of resistant SKVLB1 to the clinically approved antineoplastic agents could be increased with the addition of cytochalasins. As assessed by isobolographic analysis and Chou

  11. Doxorubicin alone versus intensified doxorubicin plus ifosfamide for first-line treatment of advanced or metastatic soft-tissue sarcoma

    DEFF Research Database (Denmark)

    Judson, Ian; Verweij, Jaap; Gelderblom, Hans

    2014-01-01

    BACKGROUND: Effective targeted treatment is unavailable for most sarcomas and doxorubicin and ifosfamide-which have been used to treat soft-tissue sarcoma for more than 30 years-still have an important role. Whether doxorubicin alone or the combination of doxorubicin and ifosfamide should be used...

  12. Comparative analysis of drug resistance mutations in the human immunodeficiency virus reverse transcriptase gene in patients who are non-responsive, responsive and naive to antiretroviral therapy.

    Science.gov (United States)

    Misbah, Mohammad; Roy, Gaurav; Shahid, Mudassar; Nag, Nalin; Kumar, Suresh; Husain, Mohammad

    2016-05-01

    Drug resistance mutations in the Pol gene of human immunodeficiency virus 1 (HIV-1) are one of the critical factors associated with antiretroviral therapy (ART) failure in HIV-1 patients. The issue of resistance to reverse transcriptase inhibitors (RTIs) in HIV infection has not been adequately addressed in the Indian subcontinent. We compared HIV-1 reverse transcriptase (RT) gene sequences to identify mutations present in HIV-1 patients who were ART non-responders, ART responders and drug naive. Genotypic drug resistance testing was performed by sequencing a 655-bp region of the RT gene from 102 HIV-1 patients, consisting of 30 ART-non-responding, 35 ART-responding and 37 drug-naive patients. The Stanford HIV Resistance Database (HIVDBv 6.2), IAS-USA mutation list, ANRS_09/2012 algorithm, and Rega v8.02 algorithm were used to interpret the pattern of drug resistance. The majority of the sequences (96 %) belonged to subtype C, and a few of them (3.9 %) to subtype A1. The frequency of drug resistance mutations observed in ART-non-responding, ART-responding and drug-naive patients was 40.1 %, 10.7 % and 20.58 %, respectively. It was observed that in non-responders, multiple mutations were present in the same patient, while in responders, a single mutation was found. Some of the drug-naive patients had more than one mutation. Thymidine analogue mutations (TAMs), however, were found in non-responders and naive patients but not in responders. Although drug resistance mutations were widely distributed among ART non-responders, the presence of resistance mutations in the viruses of drug-naive patients poses a big concern in the absence of a genotyping resistance test.

  13. Development and customization of a color-coded microbeads-based assay for drug resistance in HIV-1 reverse transcriptase.

    Science.gov (United States)

    Gu, Lijun; Kawana-Tachikawa, Ai; Shiino, Teiichiro; Nakamura, Hitomi; Koga, Michiko; Kikuchi, Tadashi; Adachi, Eisuke; Koibuchi, Tomohiko; Ishida, Takaomi; Gao, George F; Matsushita, Masaki; Sugiura, Wataru; Iwamoto, Aikichi; Hosoya, Noriaki

    2014-01-01

    Drug resistance (DR) of HIV-1 can be examined genotypically or phenotypically. Although sequencing is the gold standard of the genotypic resistance testing (GRT), high-throughput GRT targeted to the codons responsible for DR may be more appropriate for epidemiological studies and public health research. We used a Japanese database to design and synthesize sequence-specific oligonucleotide probes (SSOP) for the detection of wild-type sequences and 6 DR mutations in the clade B HIV-1 reverse transcriptase region. We coupled SSOP to microbeads of the Luminex 100 xMAP system and developed a GRT based on the polymerase chain reaction (PCR)-SSOP-Luminex method. Sixteen oligoprobes for discriminating DR mutations from wild-type sequences at 6 loci were designed and synthesized, and their sensitivity and specificity were confirmed using isogenic plasmids. The PCR-SSOP-Luminex DR assay was then compared to direct sequencing using 74 plasma specimens from treatment-naïve patients or those on failing treatment. In the majority of specimens, the results of the PCR-SSOP-Luminex DR assay were concordant with sequencing results: 62/74 (83.8%) for M41, 43/74 (58.1%) for K65, 70/74 (94.6%) for K70, 55/73 (75.3%) for K103, 63/73 (86.3%) for M184 and 68/73 (93.2%) for T215. There were a number of specimens without any positive signals, especially for K65. The nucleotide position of A2723G, A2747G and C2750T were frequent polymorphisms for the wild-type amino acids K65, K66 and D67, respectively, and 14 specimens had the D67N mutation encoded by G2748A. We synthesized 14 additional oligoprobes for K65, and the sensitivity for K65 loci improved from 43/74 (58.1%) to 68/74 (91.9%). We developed a rapid high-throughput assay for clade B HIV-1 DR mutations, which could be customized by synthesizing oligoprobes suitable for the circulating viruses. The assay could be a useful tool especially for public health research in both resource-rich and resource-limited settings.

  14. A Novel Insight into the Cardiotoxicity of Antineoplastic Drug Doxorubicin

    Directory of Open Access Journals (Sweden)

    Zbynek Heger

    2013-10-01

    Full Text Available Doxorubicin is a commonly used antineoplastic agent in the treatment of many types of cancer. Little is known about the interactions of doxorubicin with cardiac biomolecules. Serious cardiotoxicity including dilated cardiomyopathy often resulting in a fatal congestive heart failure may occur as a consequence of chemotherapy with doxorubicin. The purpose of this study was to determine the effect of exposure to doxorubicin on the changes in major amino acids in tissue of cardiac muscle (proline, taurine, glutamic acid, arginine, aspartic acid, leucine, glycine, valine, alanine, isoleucine, threonine, lysine and serine. An in vitro interaction study was performed as a comparison of amino acid profiles in heart tissue before and after application of doxorubicin. We found that doxorubicin directly influences myocardial amino acid representation even at low concentrations. In addition, we performed an interaction study that resulted in the determination of breaking points for each of analyzed amino acids. Lysine, arginine, β-alanine, valine and serine were determined as the most sensitive amino acids. Additionally we compared amino acid profiles of myocardium before and after exposure to doxorubicin. The amount of amino acids after interaction with doxorubicin was significantly reduced (p = 0.05. This fact points at an ability of doxorubicin to induce changes in quantitative composition of amino acids in myocardium. Moreover, this confirms that the interactions between doxorubicin and amino acids may act as another factor most likely responsible for adverse effects of doxorubicin on myocardium.

  15. Reversal of multidrug resistance by magnetic Fe3O4 nanoparticle copolymerizating daunorubicin and 5-bromotetrandrine in xenograft nude-mice

    OpenAIRE

    Chen, Baoan; Cheng, Jian; Wu, Yanan; Gao, Feng; Xu, Wenlin; Shen, Huilin; Ding, Jiahua; Gao, Chong; Sun, Qian; Sun, Xinchen; Cheng, Hongyan; Li, Guohong; Chen, Wenji; Chen, Ningna; Liu, Lijie

    2009-01-01

    In this paper we establish the xenograft leukemia model with stable multidrug resistance in nude mice and to investigate the reversal effect of 5-bromotetrandrine (5-BrTet) and magnetic nanoparticle of Fe3O4 (MNP-Fe3O4) combined with daunorubicin (DNR) in vivo. Two subclones of K562 and K562/A02 cells were inoculated subcutaneously into the back of athymic nude mice (1 × 107 cells/each) respectively to establish leukemia xenograft models. Drug-resistant and sensitive tumor-bearing nude mice w...

  16. Doxorubicin hepatotoxicity and hepatic free radical metabolism in rats

    International Nuclear Information System (INIS)

    Kalender, Yusuf; Yel, Mustafa; Kalender, Suna

    2005-01-01

    Doxorubicin (DXR) is an anthracycline antibiotic, broady used in tumor therapy. In the present study we investigated whether vitamin E and catechin can reduce the toxic effects of doxorubicin. Vitamin E (200 IU/kg/week), catechin (200 mg/kg/week), doxorubicin (5 mg/kg/week), doxorubicin + vitamin E (200 IU/kg/week), doxorubicin + catechin (200 mg/kg/week) combinations were given to rats weighing 210-230 g (n = 6/group). Changes in major enzymes participating in free radical metabolism superoxide dismutase (Cu,Zn-SOD), glutathione peroxidase (GSHPx), catalase (CAT) and malondialdehyde (MDA) were evaluated in the livers of all animals. Superoxide dismutase and catalase activity increased in the doxorubicin-treated group compared to control (P 0.05). Electron microscopic studies supported biochemical findings. We conclude that vitamin E and catechin significantly reduce doxorubicin-induced hepatotoxicity in rats

  17. Tetrathiomolybdate sensitizes ovarian cancer cells to anticancer drugs doxorubicin, fenretinide, 5-fluorouracil and mitomycin C

    International Nuclear Information System (INIS)

    Kim, Kyu Kwang; Lange, Thilo S; Singh, Rakesh K; Brard, Laurent; Moore, Richard G

    2012-01-01

    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. 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. 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). Our data show that TM increases the efficacy of various anticancer drugs in ovarian cancer cells in a ROS-dependent manner

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

    Science.gov (United States)

    Shen, Shida; Williamson, Morgan; Cao, Gang; Zhou, Jianshi; Goodenough, John; Tsoi, Maxim

    2017-12-01

    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.

  19. 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.

  20. Pharmacological modification of multi-drug resistance (MDR) in vitro detected by a novel fluorometric microculture cytotoxicity assay. Reversal of resistance and selective cytotoxic actions of cyclosporin A and verapamil on MDR leukemia T-cells.

    Science.gov (United States)

    Larsson, R; Nygren, P

    1990-07-15

    A novel fluorometric microculture cytotoxicity assay (FMCA), based on measurements of fluorescein diacetate (FDA) hydrolysis and DNA staining by Hoechst 33342, was used for drug sensitivity testing and detection of resistance reversal in acute lymphoblastic leukemia (ALL) cell lines. The 72-hr assay was found to be sensitive, reproducible and linearly related to the number of viable cells within a broad range of cell concentrations. At clinically achievable drug concentrations, the calcium channel blocker Verapamil (ver) and the immunosuppressant Cyclosporin A (csA) were found to partly reverse acquired Vincristine (vcr) resistance in multi-drug resistant (MDR) T-ALL L100 cells with little or no effect on the drug-sensitive parental L0 cell line. By combining the fluorometric indices, we found that low concentrations of csA were growth-inhibitory, whereas higher concentrations (greater than 10 micrograms/ml) were progressively cytotoxic for drug-sensitive L0 cells. In MDR L100 cells, on the other hand, csA produced significant cell kill even at low drug concentrations. Ver had no effects on sensitive L0 cells but showed considerable cytotoxic action towards MDR L100 cells. There was no apparent relationship between drug reversal of vcr resistance and the cytotoxic actions of the drug per se since the calcium channel blocker diltiazem (dil) significantly potentiated the actions of vcr on MDR L100 cells without being more toxic to these cells (compared to vcr-sensitive L0 cells).

  1. p21WAF1/Cip1/Sdi1 knockout mice respond to doxorubicin with reduced cardiotoxicity

    International Nuclear Information System (INIS)

    Terrand, Jerome; Xu, Beibei; Morrissy, Steve; Dinh, Thai Nho; Williams, Stuart; Chen, Qin M.

    2011-01-01

    Doxorubicin (Dox) is an antineoplastic agent that can cause cardiomyopathy in humans and experimental animals. As an inducer of reactive oxygen species and a DNA damaging agent, Dox causes elevated expression of p21 WAF1/Cip1/Sdi1 (p21) gene. Elevated levels of p21 mRNA and p21 protein have been detected in the myocardium of mice following Dox treatment. With chronic treatment of Dox, wild type (WT) animals develop cardiomyopathy evidenced by elongated nuclei, mitochondrial swelling, myofilamental disarray, reduced cardiac output, reduced ejection fraction, reduced left ventricular contractility, and elevated expression of ANF gene. In contrast, p21 knockout (p21KO) mice did not show significant changes in the same parameters in response to Dox treatment. In an effort to understand the mechanism of the resistance against Dox induced cardiomyopathy, we measured levels of antioxidant enzymes and found that p21KO mice did not contain elevated basal or inducible levels of glutathione peroxidase and catalase. Measurements of 6 circulating cytokines indicated elevation of IL-6, IL-12, IFNγ and TNFα in Dox treated WT mice but not p21KO mice. Dox induced elevation of IL-6 mRNA was detected in the myocardium of WT mice but not p21KO mice. While the mechanism of the resistance against Dox induced cardiomyopathy remains unclear, lack of inflammatory response may contribute to the observed cardiac protection in p21KO mice. -- Highlights: ► Doxorubicin induces p21 elevation in the myocardium. ► Doxorubicin causes dilated cardiomyopathy in wild type mice. ► p21 Knockout mice are resistant against doxorubicin induced cardiomyopathy. ► Lack of inflammatory response correlates with the resistance in p21 knockout mice.

  2. siRNA inhibition of telomerase enhances the anti-cancer effect of doxorubicin in breast cancer cells

    International Nuclear Information System (INIS)

    Dong, Xuejun; Liu, Anding; Zer, Cindy; Feng, Jianguo; Zhen, Zhuan; Yang, Mingfeng; Zhong, Li

    2009-01-01

    Doxorubicin is an effective breast cancer drug but is hampered by a severe, dose-dependent toxicity. Concomitant administration of doxorubicin and another cancer drug may be able to sensitize tumor cells to the cytotoxicity of doxorubicin and lowers the therapeutic dosage. In this study, we examined the combined effect of low-dose doxorubicin and siRNA inhibition of telomerase on breast cancer cells. We found that when used individually, both treatments were rapid and potent apoptosis inducers; and when the two treatments were combined, we observed an enhanced and sustained apoptosis induction in breast cancer cells. siRNA targeting the mRNA of the protein component of telomerase, the telomerase reverse transcriptase (hTERT), was transfected into two breast cancer cell lines. The siRNA inhibition was confirmed by RT-PCR and western blot on hTERT mRNA and protein levels, respectively, and by measuring the activity level of telomerase using the TRAP assay. The effect of the hTERT siRNA on the tumorigenicity of the breast cancer cells was also studied in vivo by injection of the siRNA-transfected breast cancer cells into nude mice. The effects on cell viability, apoptosis and senescence of cells treated with hTERT siRNA, doxorubicin, and the combined treatment of doxorubicin and hTERT siRNA, were examined in vitro by MTT assay, FACS and SA-β-galactosidase staining. The hTERT siRNA effectively knocked down the mRNA and protein levels of hTERT, and reduced the telomerase activity to 30% of the untreated control. In vivo, the tumors induced by the hTERT siRNA-transfected cells were of reduced sizes, indicating that the hTERT siRNA also reduced the tumorigenic potential of the breast cancer cells. The siRNA treatment reduced cell viability by 50% in breast cancer cells within two days after transfection, while 0.5 μM doxorubicin treatment had a comparable effect but with a slower kinetics. The combination of hTERT siRNA and 0.5 μM doxorubicin killed twice as many

  3. Viral resuppression and detection of drug resistance following interruption of a suppressive non-nucleoside reverse transcriptase inhibitor-based regimen

    DEFF Research Database (Denmark)

    Fox, Zoe; Phillips, Andrew; Cohen, Cal

    2008-01-01

    the NRTIs, or by replacing the NNRTI with another drug before interruption. Simultaneous interruption of all antiretrovirals was discouraged. Resuppression rates 4-8 months after reinitiating NNRTI-therapy were assessed, as was the detection of drug-resistance mutations within 2 months of the treatment...... regimen. NNRTI drug-resistance mutations were observed in a relatively high proportion of patients. These data provide additional support for a staggered or switched interruption strategy for NNRTI drugs.......BACKGROUND: Interruption of a non-nucleoside reverse transcriptase inhibitor (NNRTI)-regimen is often necessary, but must be performed with caution because NNRTIs have a low genetic barrier to resistance. Limited data exist to guide clinical practice on the best interruption strategy to use...

  4. 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.

  5. 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.

  6. ''Positive'' and ''negative'' electric-pulse-induced reversible resistance switching effect in Pr0.7Ca0.3MnO3 films

    International Nuclear Information System (INIS)

    Wang, Q.; Chen, L.D.; Li, X.M.; Shang, D.S.; Wu, Z.H.

    2007-01-01

    ''Negative'' electric-pulse-induced reversible resistance (EPIR) switching phenomenon was found in In/PCMO/Pt sandwich, in which the high resistance can be written with positive voltage pulses, and the low resistance can be reset using negative voltage pulses (the positive voltage direction is defined as going from the top electrode to the bottom electrode). This is just the opposite from the ''positive'' EPIR effect in Ag/PCMO/Pt sandwich, in which the high resistance can be written only with negative voltage pulses, and the low resistance can be reset using positive voltage pulses. The I-V hysteresis curves of In/PCMO/Pt and Ag/PCMO/Pt sandwiches also show opposite directions, i.e., counterclockwise and clockwise under a negative voltage region for indium and Ag electrode systems, respectively. C-V characteristics show that the barrier does not exist in Ag/PCMO/Pt sandwich, while In/PCMO/Pt sandwich exhibits an obvious Schottky-like barrier. We suggest that in the negative EPIR behavior in In/PCMO/Pt structure, the resistance states are mainly controlled changing the Schottky-like barrier at the interface with the weak effect of carrier trapping process, while the positive EPIR behavior in Ag/PCMO/Pt sandwich mainly depends on the carrier trapping process at the interface. (orig.)

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

    International Nuclear Information System (INIS)

    Zhou, Zhi-yong; Wan, Li-li; Yang, Quan-jun; Han, Yong-long; Li, Yan; Yu, Qi; Guo, Cheng; Li, Xiao

    2013-01-01

    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 0–t and C 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

  8. 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.

  9. Novel function of N,N-bis(2-chloroethyl)docos-13-enamide for reversal of multidrug resistance in tongue cancer.

    Science.gov (United States)

    Qin, Qing; Ma, Peng-Fei; Kuang, Xiao-Cong; Gao, Ming-Xing; Mo, De-Huan; Xia, Shuang; Jin, Ning; Xia, Jun-Jie; Qi, Zhong-Quan; Lin, Cui-Wu

    2013-12-05

    Multidrug resistance (MDR) is a key element in the failure of chemotherapies, and development of agents to overcome MDR is crucial to improving cancer treatments. The overexpression of glutathione-S-transferases (GSTs) is one of the major mechanisms of MDR. Because some agents used in traditional Chinese medicine have strong antitumor effects coupled with low toxicity; we investigated the ability of N,N-bis(2-chloroethyl)docos-13-enamide (compound J), the synthesized analog of a highly unsaturated fatty acid from Isatis tinctoria L., to reverse the MDR induced by adriamycin (ADM) in TCA8113/ADM cells. We found that compound J significantly increased the cytotoxicity of ADM in TCA8113/ADM cells, with a reversal fold of 2.461. Analysis of the mechanisms through which compound J reversed MDR indicated that compound J significantly decreased the activity of GSTs and enhanced the depletion of GSH in TCA8113/ADM cells, but did not affect the P-glycoprotein (P-gp) efflux. Taken together, our data suggested that compound J was an excellent candidate for reversing MDR in cancer therapy. © 2013 Published by Elsevier B.V.

  10. Epigenetic modulation of the biophysical properties of drug-resistant cell lipids to restore drug transport and endocytic functions.

    Science.gov (United States)

    Vijayaraghavalu, Sivakumar; Peetla, Chiranjeevi; Lu, Shan; Labhasetwar, Vinod

    2012-09-04

    In our recent studies exploring the biophysical characteristics of resistant cell lipids, and the role they play in drug transport, we demonstrated the difference of drug-resistant breast cancer cells from drug-sensitive cells in lipid composition and biophysical properties, suggesting that cancer cells acquire a drug-resistant phenotype through the alteration of lipid synthesis to inhibit intracellular drug transport to protect from cytotoxic effect. In cancer cells, epigenetic changes (e.g., DNA hypermethylation) are essential to maintain this drug-resistant phenotype. Thus, altered lipid synthesis may be linked to epigenetic mechanisms of drug resistance. We hypothesize that reversing DNA hypermethylation in resistant cells with an epigenetic drug could alter lipid synthesis, changing the cell membrane's biophysical properties to facilitate drug delivery to overcome drug resistance. Herein we show that treating drug-resistant breast cancer cells (MCF-7/ADR) with the epigenetic drug 5-aza-2'-deoxycytidine (decitabine) significantly alters cell lipid composition and biophysical properties, causing the resistant cells to acquire biophysical characteristics similar to those of sensitive cell (MCF-7) lipids. Following decitabine treatment, resistant cells demonstrated increased sphingomyelinase activity, resulting in a decreased sphingomyelin level that influenced lipid domain structures, increased membrane fluidity, and reduced P-glycoprotein expression. Changes in the biophysical characteristics of resistant cell lipids facilitated doxorubicin transport and restored endocytic function for drug delivery with a lipid-encapsulated form of doxorubicin, enhancing the drug efficacy. In conclusion, we have established a new mechanism for efficacy of an epigenetic drug, mediated through changes in lipid composition and biophysical properties, in reversing cancer drug resistance.

  11. Etravirine and rilpivirine resistance in HIV-1 subtype CRF01_AE-infected adults failing non-nucleoside reverse transcriptase inhibitor-based regimens.

    Science.gov (United States)

    Bunupuradah, Torsak; Ananworanich, Jintanat; Chetchotisakd, Ploenchan; Kantipong, Pacharee; Jirajariyavej, Supunnee; Sirivichayakul, Sunee; Munsakul, Warangkana; Prasithsirikul, Wisit; Sungkanuparph, Somnuek; Bowonwattanuwong, Chureeratana; Klinbuayaem, Virat; Petoumenos, Kathy; Hirschel, Bernard; Bhakeecheep, Sorakij; Ruxrungtham, Kiat

    2011-01-01

    We studied prevalence of etravirine (ETR) and rilpivirine (RPV) resistance in HIV-1 subtype CRF01_AE infection with first-line non-nucleoside reverse transcriptase inhibitor (NNRTI) failure. A total of 225 adults failing two nucleoside reverse transcriptase inhibitors (NRTIs) plus 1 NNRTI in Thailand with HIV RNA>1,000 copies/ml were included. Genotypic resistance results and HIV-1 subtype were interpreted by Stanford DR database. ETR resistance was calculated by the new Monogram weighted score (Monogram WS; ≥ 4 indicating high-level ETR resistance) and by DUET weighted score (DUET WS; 2.5-3.5 and ≥ 4 resulted in intermediate and reduce ETR response, respectively). RPV resistance interpretation was based on previous reports. Median (IQR) age was 38 (34-42) years, 41% were female and CDC A:B:C were 22%:21%:57%. HIV subtypes were 96% CRF01_AE and 4% B. Antiretrovirals at failure were lamivudine (100%), stavudine (93%), nevirapine (90%) and efavirenz (10%) with a median (IQR) duration of 3.4 (1.8-4.5) years. Median (IQR) CD4(+) T-cell count and HIV RNA were 194 (121-280) cells/mm³ and 4.1 (3.6-4.6) log₁₀ copies/ml, respectively. The common NNRTI mutations were Y181C (41%), G190A (22%) and K103N (19%). The proportion of patients with Monogram WS score ≥ 4 was 61.3%. By DUET WS, 49.8% and 7.5% of patients were scored 2.5-3.5 and ≥4, respectively. Only HIV RNA ≥ 4 log₁₀ copies/ml at failure was associated with both Monogram WS ≥ 4 (OR 2.3, 95% CI 1.3-3.9; P=0.003) and DUET WS ≥ 2.5 (OR 1.9, 95% CI 1.1-3.3; P=0.02). The RVP resistance-associated mutations (RAMs) detected were K101P (1.8%), Y181I (2.7%) and Y181V (3.6%). All patients with RPV mutation had ETR resistance. No E138R/E138K mutations were detected. Approximately 60% of patients had high-level ETR resistance. The role of ETR in second-line therapy is limited in late NNRTI failure settings. RVP RAMs were uncommon, but cross-resistance between ETR and RVP was high.

  12. Active methamphetamine use is associated with transmitted drug resistance to non-nucleoside reverse transcriptase inhibitors in individuals with HIV infection of unknown duration.

    Science.gov (United States)

    Cachay, Edward R; Moini, Niousha; Kosakovsky Pond, Sergei L; Pesano, Rick; Lie, Yolanda S; Aiem, Heidi; Butler, David M; Letendre, Scott; Mathews, Wm Christopher; Smith, Davey M

    2007-01-01

    Frequent methamphetamine use among recently HIV infected individuals is associated with transmitted drug resistance (TDR) to non-nucleoside reverse transcriptase inhibitors (NNRTI); however, the reversion time of TDR to drug susceptible HIV may exceed 3 years. We assessed whether recreational substance use is associated with detectable TDR among individuals newly diagnosed with HIV infection of unknown duration. Cross-sectional analysis. Subjects were enrolled at the University California, San Diego Early Intervention Program. Demographic, clinical and substance use data were collected using structured interviews. Genotypic resistance testing was performed using GeneSeq, Monogram Biosciences. We analyzed the association between substance use and TDR using bivariate analyses and the corresponding transmission networks using phylogenetic models. Between April 2004 and July 2006, 115 individuals with genotype data were enrolled. The prevalence of alcohol, marijuana and methamphetamine use were 98%, 71% and 64% respectively. Only active methamphetamine use in the 30 days prior to HIV diagnosis was independently associated with TDR to NNRTI (OR: 6.6; p=0.002). Despite not knowing the duration of their HIV infection, individuals reporting active methamphetamine use in the 30 days prior to HIV diagnosis are at an increased risk of having HIV strains that are resistant to NNRTI.

  13. Active Methamphetamine Use is Associated with Transmitted Drug Resis-tance to Non-Nucleoside Reverse Transcriptase Inhibitors in Individuals with HIV Infection of Unknown Duration

    Science.gov (United States)

    Cachay, Edward R; Moini, Niousha; Kosakovsky Pond, Sergei L; Pesano, Rick; Lie, Yolanda S; Aiem, Heidi; Butler, David M; Letendre, Scott; Mathews, Wm. Christopher; Smith, Davey M

    2007-01-01

    Background: Frequent methamphetamine use among recently HIV infected individuals is associated with transmitted drug resistance (TDR) to non-nucleoside reverse transcriptase inhibitors (NNRTI); however, the reversion time of TDR to drug susceptible HIV may exceed 3 years. We assessed whether recreational substance use is associated with detectable TDR among individuals newly diagnosed with HIV infection of unknown duration. Design: Cross-sectional analysis. Methods: Subjects were enrolled at the University California, San Diego Early Intervention Program. Demographic, clinical and substance use data were collected using structured interviews. Genotypic resistance testing was performed using GeneSeq™, Monogram Biosciences. We analyzed the association between substance use and TDR using bivariate analyses and the corresponding transmission networks using phylogenetic models. Results: Between April 2004 and July 2006, 115 individuals with genotype data were enrolled. The prevalence of alcohol, marijuana and methamphetamine use were 98%, 71% and 64% respectively. Only active methamphetamine use in the 30 days prior to HIV diagnosis was independently associated with TDR to NNRTI (OR: 6.6; p=0.002). Conclusion: Despite not knowing the duration of their HIV infection, individuals reporting active methamphetamine use in the 30 days prior to HIV diagnosis are at an increased risk of having HIV strains that are resistant to NNRTI. PMID:18923691

  14. Substrate Stiffness Influences Doxorubicin-Induced p53 Activation via ROCK2 Expression

    Directory of Open Access Journals (Sweden)

    Takahiro Ebata

    2017-01-01

    Full Text Available The physical properties of the extracellular matrix (ECM, such as stiffness, are involved in the determination of the characteristics of cancer cells, including chemotherapy sensitivity. Resistance to chemotherapy is often linked to dysfunction of tumor suppressor p53; however, it remains elusive whether the ECM microenvironment interferes with p53 activation in cancer cells. Here, we show that, in MCF-7 breast cancer cells, extracellular stiffness influences p53 activation induced by the antitumor drug doxorubicin. Cell growth inhibition by doxorubicin was increased in response to ECM rigidity in a p53-dependent manner. The expression of Rho-associated coiled coil-containing protein kinase (ROCK 2, which induces the activation of myosin II, was significantly higher when cells were cultured on stiffer ECM substrates. Knockdown of ROCK2 expression or pharmacological inhibition of ROCK decreased doxorubicin-induced p53 activation. Our results suggest that a soft ECM causes downregulation of ROCK2 expression, which drives resistance to chemotherapy by repressing p53 activation.

  15. Reversal of multidrug resistance by magnetic Fe3O4 nanoparticle copolymerizating daunorubicin and 5-bromotetrandrine in xenograft nude-mice

    OpenAIRE

    Chen, Baoan

    2009-01-01

    Baoan Chen1,* Jian Cheng1,* Yanan Wu1, Feng Gao1, Wenlin Xu2, et al 1Department of Hematology;2Department of Hematology, The Affiliated People’s Hospital, Jiangsu University, Zhenjiang, PR China *These authors have contributed equally to this workAbstract: In this paper we establish the xenograft leukemia model with stable multidrug resistance in nude mice and to investigate the reversal effect of 5-bromotetrandrine (5-BrTet) and magnetic nanoparticle of Fe3O4 (MNP-Fe3O4) c...

  16. A new class of potential chloroquine-resistance reversal agents for Plasmodia: syntheses and biological evaluation of 1-(3'-diethylaminopropyl)-3-(substituted phenylmethylene)pyrrolidines.

    Science.gov (United States)

    Batra, S; Srivastava, P; Roy, K; Pandey, V C; Bhaduri, A P

    2000-09-07

    1-(3'-Diethylaminopropyl)-3-(substituted phenylmethylene)pyrrolidines were synthesized and evaluated for CQ-resistant reversal activity. In general the compounds of the series elicit better biological response than their phenylmethyl analogues. The most active compound 4b has been evaluated in vivo in detail, and the results are presented. The possible mode of action of the compounds of this series is by inhibition of the enzyme heme oxygenase, thereby increasing the levels of heme and hemozoin, which are lethal to the parasite.

  17. 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.

  18. P-glycoprotein inhibition of drug resistant cell lines by nanoparticles.

    Science.gov (United States)

    Singh, Manu Smriti; Lamprecht, Alf

    2016-01-01

    Several pharmaceutical excipients are known for their ability to interact with cell membrane lipids and reverse the phenomenon of multidrug resistance (MDR) in cancer. Interestingly, many excipients act as stabilizers and are key ingredients in a variety of nano-formulations. In this study, representatives of ionic and non-ionic excipients were used as surface active agents in nanoparticle (NP) formulations to utilize their MDR reversing potential. In-vitro assays were performed to elucidate particle-cell interaction and accumulation of P-glycoprotein (P-gp) substrates-rhodamine-123 and calcein AM, in highly drug resistant glioma cell lines. Chemosensitization achieved using NPs and their equivalent dose of free excipients was assessed with the co-administered anti-cancer drug doxorubicin. Among the excipients used, non-ionic surfactant, Cremophor® EL, and cationic surfactant, cetyltrimethylammonuium bromide (CTAB), demonstrated highest P-gp modulatory activity in both free solution form (up to 7-fold lower IC50) and as a formulation (up to 4.7-fold lower IC50) as compared to doxorubicin treatment alone. Solutol® HS15 and Tween® 80 exhibited considerable chemosensitization as free solution but not when incorporated into a formulation. Sodium dodecyl sulphate (SDS)-based nanocarriers resulted in slightly improved cytotoxicity. Overall, the results highlight and envisage the usage of excipient in nano-formulations in a bid to improve chemosensitization of drug resistant cancer cells towards anti-cancer drugs.

  19. 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.

  20. 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.

  1. Etravirine and Rilpivirine Drug Resistance Among HIV-1 Subtype C Infected Children Failing Non-Nucleoside Reverse Transcriptase Inhibitor-Based Regimens in South India.

    Science.gov (United States)

    Saravanan, Shanmugam; Kausalya, Bagavathi; Gomathi, Selvamurthi; Sivamalar, Sathasivam; Pachamuthu, Balakrishnan; Selvamuthu, Poongulali; Pradeep, Amrose; Sunil, Solomon; Mothi, Sarvode N; Smith, Davey M; Kantor, Rami

    2017-06-01

    We have analyzed reverse transcriptase (RT) region of HIV-1 pol gene from 97 HIV-infected children who were identified as failing first-line therapy that included first-generation non-nucleoside RT inhibitors (Nevirapine and Efavirenz) for at least 6 months. We found that 54% and 65% of the children had genotypically predicted resistance to second-generation non-nucleoside RT inhibitors drugs Etravirine (ETR) and Rilpivirine, respectively. These cross-resistance mutations may compromise future NNRTI-based regimens, especially in resource-limited settings. To complement these investigations, we also analyzed the sequences in Stanford database, Monogram weighted score, and DUET weighted score algorithms for ETR susceptibility and found almost perfect agreement between the three algorithms in predicting ETR susceptibility from genotypic data.

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

    OpenAIRE

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

    2017-01-01

    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 thi...

  3. 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.

  4. TVP1022 and propargylamine protect neonatal rat ventricular myocytes against doxorubicin-induced and serum starvation-induced cardiotoxicity.

    Science.gov (United States)

    Kleiner, Yana; Bar-Am, Orit; Amit, Tamar; Berdichevski, Alexandra; Liani, Esti; Maor, Gila; Reiter, Irina; Youdim, Moussa B H; Binah, Ofer

    2008-09-01

    We recently reported that propargylamine derivatives such as rasagiline (Azilect) and its S-isomer TVP1022 are neuroprotective. The aim of this study was to test the hypothesis that the neuroprotective agents TVP1022 and propargylamine (the active moiety of propargylamine derivatives) are also cardioprotective. We specifically investigated the protective efficacy of TVP1022 and propargylamine in neonatal rat ventricular myocytes (NRVM) against apoptosis induced by the anthracycline chemotherapeutic agent doxorubicin and by serum starvation. We demonstrated that pretreatment of NRVM cultures with TVP1022 or propargylamine attenuated doxorubicin-induced and serum starvation-induced apoptosis, inhibited the increase in cleaved caspase 3 levels, and reversed the decline in Bcl-2/Bax ratio. These cytoprotective effects were shown to reside in the propargylamine moiety. Finally, we showed that TVP1022 neither caused proliferation of the human cancer cell lines HeLa and MDA-231 nor interfered with the anti-cancer efficacy of doxorubicin. These results suggest that TVP1022 should be considered as a novel cardioprotective agent against ischemic insults and against anthracycline cardiotoxicity and can be coadministered with doxorubicin in the treatment of human malignancies.

  5. Prediction of the binding mode and resistance profile for a dual-target pyrrolyl diketo acid scaffold against HIV-1 integrase and reverse-transcriptase-associated ribonuclease H.

    Science.gov (United States)

    Yang, Fengyuan; Zheng, Guoxun; Fu, Tingting; Li, Xiaofeng; Tu, Gao; Li, Ying Hong; Yao, Xiaojun; Xue, Weiwei; Zhu, Feng

    2018-06-27

    The rapid emergence of drug-resistant variants is one of the most common causes of highly active antiretroviral therapeutic (HAART) failure in patients infected with HIV-1. Compared with the existing HAART, the recently developed pyrrolyl diketo acid scaffold targeting both HIV-1 integrase (IN) and reverse transcriptase-associated ribonuclease H (RNase H) is an efficient approach to counteract the failure of anti-HIV treatment due to drug resistance. However, the binding mode and potential resistance profile of these inhibitors with important mechanistic principles remain poorly understood. To address this issue, an integrated computational method was employed to investigate the binding mode of inhibitor JMC6F with HIV-1 IN and RNase H. By using per-residue binding free energy decomposition analysis, the following residues: Asp64, Thr66, Leu68, Asp116, Tyr143, Gln148 and Glu152 in IN, Asp443, Glu478, Trp536, Lys541 and Asp549 in RNase H were identified as key residues for JMC6F binding. And then computational alanine scanning was carried to further verify the key residues. Moreover, the resistance profile of the currently known major mutations in HIV-1 IN and 2 mutations in RNase H against JMC6F was predicted by in silico mutagenesis studies. The results demonstrated that only three mutations in HIV-1 IN (Y143C, Q148R and N155H) and two mutations in HIV-1 RNase H (Y501R and Y501W) resulted in a reduction of JMC6F potency, thus indicating their potential role in providing resistance to JMC6F. These data provided important insights into the binding mode and resistance profile of the inhibitors with a pyrrolyl diketo acid scaffold in HIV-1 IN and RNase H, which would be helpful for the development of more effective dual HIV-1 IN and RNase H inhibitors.

  6. Doxorubicin Blocks Cardiomyocyte Autophagic Flux by Inhibiting Lysosome Acidification.

    Science.gov (United States)

    Li, Dan L; Wang, Zhao V; Ding, Guanqiao; Tan, Wei; Luo, Xiang; Criollo, Alfredo; Xie, Min; Jiang, Nan; May, Herman; Kyrychenko, Viktoriia; Schneider, Jay W; Gillette, Thomas G; Hill, Joseph A

    2016-04-26

    The clinical use of doxorubicin is limited by cardiotoxicity. Histopathological changes include interstitial myocardial fibrosis and the appearance of vacuolated cardiomyocytes. Whereas dysregulation of autophagy in the myocardium has been implicated in a variety of cardiovascular diseases, the role of autophagy in doxorubicin cardiomyopathy remains poorly defined. Most models of doxorubicin cardiotoxicity involve intraperitoneal injection of high-dose drug, which elicits lethargy, anorexia, weight loss, and peritoneal fibrosis, all of which confound the interpretation of autophagy. Given this, we first established a model that provokes modest and progressive cardiotoxicity without constitutional symptoms, reminiscent of the effects seen in patients. We report that doxorubicin blocks cardiomyocyte autophagic flux in vivo and in cardiomyocytes in culture. This block was accompanied by robust accumulation of undegraded autolysosomes. We go on to localize the site of block as a defect in lysosome acidification. To test the functional relevance of doxorubicin-triggered autolysosome accumulation, we studied animals with diminished autophagic activity resulting from haploinsufficiency for Beclin 1. Beclin 1(+/-) mice exposed to doxorubicin were protected in terms of structural and functional changes within the myocardium. Conversely, animals overexpressing Beclin 1 manifested an amplified cardiotoxic response. Doxorubicin blocks autophagic flux in cardiomyocytes by impairing lysosome acidification and lysosomal function. Reducing autophagy initiation protects against doxorubicin cardiotoxicity. © 2016 American Heart Association, Inc.

  7. Direct effects of doxorubicin on skeletal muscle contribute to fatigue

    NARCIS (Netherlands)

    Norren, van K.; Helvoort, van A.; Argiles, J.M.; Tuijl, van S.; Arts, K.; Gorselink, M.; Laviano, A.; Kegler, D.; Haagsman, H.P.; Beek, E.M.

    2009-01-01

    Chemotherapy-induced fatigue is a multidimensional symptom. Oxidative stress has been proposed as a working mechanism for anthracycline-induced cardiotoxicity. In this study, doxorubicin (DOX) was tested on skeletal muscle function. Doxorubicin induced impaired ex vivo skeletal muscle relaxation

  8. Depleted aldehyde dehydrogenase 1A1 (ALDH1A1) reverses cisplatin resistance of human lung adenocarcinoma cell A549/DDP.

    Science.gov (United States)

    Wei, Yunyan; Wu, Shuangshuang; Xu, Wei; Liang, Yan; Li, Yue; Zhao, Weihong; Wu, Jianqing

    2017-01-01

    Cisplatin is the standard first-line chemotherapeutic agent for the treatment of non-small cell lung cancer (NSCLC). However, resistance to chemotherapy has been a major obstacle in the management of NSCLC. Aldehyde dehydrogenase 1A1 (ALDH1A1) overexpression has been observed in a variety of cancers, including lung cancer. The purpose of this study was to investigate the effect of ALDH1A1 expression on cisplatin resistance and explore the mechanism responsible. Reverse transcriptase-PCR was applied to measure the messenger RNA expression of ALDH1A1, while Western blot assay was employed to evaluate the protein expression of ALDH1A1, B-cell lymphoma 2, Bcl-2-like protein 4, phospho-protein kinase B (p-AKT) and AKT. A short hairpin RNA was used to knockdown ALDH1A1 expression. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to determine the effect of ALDH1A1 decrease on cell viability. The cell apoptotic rate was tested using flow cytometry assay. ALDH1A1 is overexpressed in cisplatin resistant cell line A549/DDP, compared with A549. ALDH1A1 depletion significantly decreased A549/DDP proliferation, increased apoptosis, and reduced cisplatin resistance. In addition, the phosphoinositide 3-kinase (PI3K) / AKT pathway is activated in A549/DDP, and ALDH1A1 knockdown reduced the phosphorylation level of AKT. Moreover, the combination of ALDH1A1-short hairpin RNA and PI3K/AKT pathway inhibitor LY294002 markedly inhibited cell viability, enhanced apoptotic cell death, and increased cisplatin sensitivity. These results suggest that ALDH1A1 depletion could reverse cisplatin resistance in human lung cancer cell line A549/DDP, and may act as a potential target for the treatment of lung cancers resistant to cisplatin. © 2016 The Authors. Thoracic Cancer published by China Lung Oncology Group and John Wiley & Sons Australia, Ltd.

  9. HPMA copolymer-bound doxorubicin induces immunogenic tumor cell death.

    Science.gov (United States)

    Sirova, M; Kabesova, M; Kovar, L; Etrych, T; Strohalm, J; Ulbrich, K; Rihova, B

    2013-01-01

    Treatment of murine EL4 T cell lymphoma with N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer conjugates of doxorubicin (Dox) leads to complete tumor regression and to the development of therapy-dependent longlasting cancer resistance. This phenomenon occurs with two types of Dox conjugates tested, despite differences in the covalent linkage of Dox to the polymer carrier. Such a cancer resistance cannot fully express in conventional treatment with free Dox, due to substantial immunotoxicity of the treatment, which was not observed in the polymer conjugates. In this study, calreticulin (CRT) translocation and high mobility group box-1 protein (HMGB1) release was observed in EL4 cells treated with a conjugate releasing Dox by a pH-dependent manner. As a result, the treated tumor cells were engulfed by dendritic cells (DC) in vitro, and induced their expression of CD80, CD86, and MHC II maturation markers. Conjugates with Dox bound via an amide bond only increased translocation of HSPs to the membrane, which led to an elevated phagocytosis but was not sufficient to induce increase of the maturation markers on DCs in vitro. Both types of conjugates induced engulfment of the target tumor cells in vivo, that was more intense than that seen with free Dox. It means that the induction of anti-tumor immunity documented upon treatment of EL4 lymphoma with HPMA-bound Dox conjugates does not rely solely on CRT-mediated cell death, but involves multiple mechanisms.

  10. 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.

  11. 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...

  12. 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.

  13. Reduced skeletal muscle inhibitor of kappaB beta content is associated with insulin resistance in subjects with type 2 diabetes: reversal by exercise training.

    Science.gov (United States)

    Sriwijitkamol, Apiradee; Christ-Roberts, Christine; Berria, Rachele; Eagan, Phyllis; Pratipanawatr, Thongchai; DeFronzo, Ralph A; Mandarino, Lawrence J; Musi, Nicolas

    2006-03-01

    Skeletal muscle insulin resistance plays a key role in the pathogenesis of type 2 diabetes. It recently has been hypothesized that excessive activity of the inhibitor of kappaB (IkappaB)/nuclear factor kappaB (NFkappaB) inflammatory pathway is a mechanism underlying skeletal muscle insulin resistance. However, it is not known whether IkappaB/NFkappaB signaling in muscle from subjects with type 2 diabetes is abnormal. We studied IkappaB/NFkappaB signaling in vastus lateralis muscle from six subjects with type 2 diabetes and eight matched control subjects. Muscle from type 2 diabetic subjects was characterized by a 60% decrease in IkappaB beta protein abundance, an indicator of increased activation of the IkappaB/NFkappaB pathway. IkappaB beta abundance directly correlated with insulin-mediated glucose disposal (Rd) during a hyperinsulinemic (40 mU x m(-2) x min(-1))-euglycemic clamp (r = 0.63, P = 0.01), indicating that increased IkappaB/NFkappaB pathway activity is associated with muscle insulin resistance. We also investigated whether reversal of this abnormality could be a mechanism by which training improves insulin sensitivity. In control subjects, 8 weeks of aerobic exercise training caused a 50% increase in both IkappaB alpha and IkappaB beta protein. In subjects with type 2 diabetes, training increased IkappaB alpha and IkappaB beta protein to levels comparable with that of control subjects, and these increments were accompanied by a 40% decrease in tumor necrosis factor alpha muscle content and a 37% increase in insulin-stimulated glucose disposal. In summary, subjects with type 2 diabetes have reduced IkappaB protein abundance in muscle, suggesting excessive activity of the IkappaB/NFkappaB pathway. Moreover, this abnormality is reversed by exercise training.

  14. Tretinoin-loaded lipid-core nanocapsules overcome the triple-negative breast cancer cell resistance to tretinoin and show synergistic effect on cytotoxicity induced by doxorubicin and 5-fluororacil.

    Science.gov (United States)

    Schultze, Eduarda; Buss, Julieti; Coradini, Karine; Begnini, Karine Rech; Guterres, Silvia S; Collares, Tiago; Beck, Ruy Carlos Ruver; Pohlmann, Adriana R; Seixas, Fabiana Kömmling

    2017-12-01

    Nanostructured drug delivery systems have been extensively studied, mainly for applications in cancer therapy. The advantages of these materials include protection against drug degradation and improvement in both the relative solubility of poorly water soluble drugs as in targeting of therapy, due to the enhanced permeability and retention effect on tumor sites. In this work, we evaluate the antitumor activity of tretinoin-loaded lipid core nanocapsules (TT-LNC) in a tretinoin-resistant breast cancer cell-line, MDA-MB- 231, as well as the synergistic effect of combination of this treatment with 5-FU or DOXO. The inhibition of cell growth was assayed by MTT reduction. Live/Dead assay and DAPI staining evaluated cytotoxicity. Apoptosis was evaluated by Annexin V-PE/7AAD and the effect of chronic exposure was evaluated by colony formation assay. TT-LNC reduced the cell viability even at lower concentrations (1μM) and displayed synergistic effect with 5-FU or DOXO on cytotoxicity and colony formation inhibition. Our work shows a possibility of using nanocapsules to improve the antitumoral activity of TT for its use either alone or in combination with other chemotherapeutic drugs, especially considering the chronic effect. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  15. Tissue factor/FVIIa activates Bcl-2 and prevents doxorubicin-induced apoptosis in neuroblastoma cells

    International Nuclear Information System (INIS)

    Fang, Jun; Gu, Lubing; Zhu, Ningxi; Tang, Hao; Alvarado, Carlos S; Zhou, Muxiang

    2008-01-01

    Tissue factor (TF) is a transmembrane protein that acts as a receptor for activated coagulation factor VII (FVIIa), initiating the coagulation cascade. Recent studies demonstrate that expression of tumor-derived TF also mediates intracellular signaling relevant to tumor growth and apoptosis. Our present study investigates the possible mechanism by which the interaction between TF and FVIIa regulates chemotherapy resistance in neuroblastoma cell lines. Gene and siRNA transfection was used to enforce TF expression in a TF-negative neuroblastoma cell line and to silence endogenous TF expression in a TF-overexpressing neuroblastoma line, respectively. The expression of TF, Bcl-2, STAT5, and Akt as well as the phosphorylation of STAT5 and Akt in gene transfected cells or cells treated with JAK inhibitor and LY294002 were determined by Western blot assay. Tumor cell growth was determined by a clonogenic assay. Cytotoxic and apoptotic effect of doxorubicin on neuroblastoma cell lines was analyzed by WST assay and annexin-V staining (by flow cytometry) respectively. Enforced expression of TF in a TF-negative neuroblastoma cell line in the presence of FVIIa induced upregulation of Bcl-2, leading to resistance to doxorubicin. Conversely, inhibition of endogenous TF expression in a TF-overexpressing neuroblastoma cell line using siRNA resulted in down-regulation of Bcl-2 and sensitization to doxorubicin-induced apoptosis. Additionally, neuroblastoma cells expressing high levels of either endogenous or transfected TF treated with FVIIa readily phosphorylated STAT5 and Akt. Using selective pharmacologic inhibitors, we demonstrated that JAK inhibitor I, but not the PI3K inhibitor LY294002, blocked the TF/FVIIa-induced upregulation of Bcl-2. This study shows that in neuroblastoma cell lines overexpressed TF ligated with FVIIa produced upregulation of Bcl-2 expression through the JAK/STAT5 signaling pathway, resulting in resistance to apoptosis. We surmise that this TF

  16. In vitro and in vivo reversal of cancer cell multidrug resistance by the semi-synthetic antibiotic tiamulin.

    Science.gov (United States)

    Baggetto, L G; Dong, M; Bernaud, J; Espinosa, L; Rigal, D; Bonvallet, R; Marthinet, E

    1998-11-01

    A large number of multidrug resistance (MDR) modulators, termed chemosensitizers, have been identified from a variety of chemicals, but most have been proven to be clinically toxic. Low concentrations of the pleuromutilin-derived semi-synthetic antibiotic tiamulin (0.1 to 10 microM) sensitized the three highly resistant P-glycoprotein (Pgp)-overexpressing tumor cell lines P388 (murine lymphoid leukemia), AS30-D (rat hepatoma), CEM (human lymphoblastic leukemia), and the barely resistant AS30-D/S cell lines to several MDR-related anticancer drugs. Flow cytometric analysis showed that tiamulin significantly increased the intracellular accumulation of daunomycin. When compared to reference modulating agents such as verapamil and cyclosporin A, tiamulin proved to be 1.1 to 8.3 times more efficient in sensitizing the resistant cell lines. Moreover, when given i.p. (1.6 microg/mg body weight), tiamulin increased the survival rate of adriamycin-treated mice bearing the P388/ADR25 tumor line by 29%. In the presence of an anticancer drug, tiamulin inhibited both ATPase and drug transport activities of Pgp in plasma membranes from tumor cells. Tiamulin is thus a potent chemosensitizer that antagonizes the Pgp-mediated chemoresistance in many tumor cell lines expressing the MDR phenotype at different levels and displays no toxic effects on contractile tissues at active doses, therefore providing the promise for potential clinical applications.

  17. PEGylated polylysine dendrimers increase lymphatic exposure to doxorubicin when compared to PEGylated liposomal and solution formulations of doxorubicin.

    Science.gov (United States)

    Ryan, Gemma M; Kaminskas, Lisa M; Bulitta, Jürgen B; McIntosh, Michelle P; Owen, David J; Porter, Christopher J H

    2013-11-28

    Improved delivery of chemotherapeutic drugs to the lymphatic system has the potential to augment outcomes for cancer therapy by enhancing activity against lymph node metastases. Uptake of small molecule chemotherapeutics into the lymphatic system, however, is limited. Nano-sized drug carriers have the potential to promote access to the lymphatics, but to this point, this has not been examined in detail. The current study therefore evaluated the lymphatic exposure of doxorubicin after subcutaneous and intravenous administration as a simple solution formulation or when formulated as a doxorubicin loaded PEGylated poly-lysine dendrimer (hydrodynamic diameter 12 nm), a PEGylated liposome (100 nm) and various pluronic micellar formulations (~5 nm) to thoracic lymph duct cannulated rats. Plasma and lymph pharmacokinetics were analysed by compartmental pharmacokinetic modelling in S-ADAPT, and Berkeley Madonna software was used to predict the lymphatic exposure of doxorubicin over an extended period of time. The micelle formulations displayed poor in vivo stability, resulting in doxorubicin profiles that were similar to that observed after administration of the doxorubicin solution formulation. In contrast, the dendrimer formulation significantly increased the recovery of doxorubicin in the thoracic lymph after both intravenous and subcutaneous dosing when compared to the solution or micellar formulation. Dendrimer-doxorubicin also resulted in increases in lymphatic doxorubicin concentrations when compared to the liposome formulation, although liposomal doxorubicin did increase lymphatic transport when compared to the solution formulation. Specifically, the dendrimer formulation increased the recovery of doxorubicin in the lymph up to 30 h post dose by up to 685 fold and 3.7 fold when compared to the solution and liposomal formulations respectively. Using the compartmental model to predict lymphatic exposure to longer time periods suggested that doxorubicin exposure to

  18. Lactoferricin B reverses cisplatin resistance in head and neck squamous cell carcinoma cells through targeting PD-L1.

    Science.gov (United States)

    Zhang, Pei; Liu, Jinzhong; Li, Wenlu; Li, Shanshan; Han, Xinguang

    2018-05-15

    Head and neck squamous cell carcinoma (HNSCC) ranks among the top most common cancers with a poor prognosis. The mechanism of chemoresistance is still not well known. This study is to investigate the programmed death-ligand 1 (PD-L1) expression in HNSCC, and test the effect of lactoferricin B (LfcinB) on chemoresistance and its mechanism. We analyzed 510 HNSCC patients in TCGA database and investigated how CD274 expression was related to patient prognosis. PD-L1 was verified from HNSCC samples at local hospital with immunohistochemistry. PD-L1 expression in the acquired cisplatin-resistant HNSCC cells was examined by PCR and WB in order to test PD-L1-induced chemoresistance. LfcinB inoculation in cisplatin-resistant HNSCC cells and in the nude mice was introduced to test the effect of LfcinB on targeting cisplatin resistance and its mechanism. High CD274 mRNA (>125 FPKM) from TCGA database had a significantly reduced 5-year survival rate, and a lower 5-year survival rate in the chemotherapy and radiotherapy-treated patients (P < .05). PD-L1 overexpression was further supported from analysis of 40 HNSCC specimens. PD-L1 and IL-6 in the established cisplatin-resistant HNSCC cells were shown significantly higher (P < .05). IL-6 and PD-L1 expression were partially inhibited by the anti-IL-6/STAT3 antibody. LfcinB displayed a direct cytotoxic effect on cisplatin-resistant HNSCC cells and HNSCC xenografts of cisplatin-resistant cells in the nude mice displayed significant reduction in tumor volume after LfcinB injection (P < .05). Besides, the increase of IL-6 and PD-L1 in cisplatin-resistant HNSCC cells was abolished in vitro by LfcinB (P < .05). PD-L1 expression in HNSCC cells correlates with poor prognosis and chemoresistance, and LfcinB might provide therapeutic potential in HNSCC patients through modulating IL-6 and PD-L1. © 2018 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.

  19. 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.

  20. 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.

  1. Salvianolic acid A reverses cisplatin resistance in lung cancer A549 cells by targeting c-met and attenuating Akt/mTOR pathway.

    Science.gov (United States)

    Tang, Xia-Li; Yan, Li; Zhu, Ling; Jiao, De-Min; Chen, Jun; Chen, Qing-Yong

    2017-09-01

    Drug resistance is one of the leading causes of chemotherapy failure in non-small cell lung cancer (NSCLC) treatment. The purpose of this study was to investigate the role of c-met in human lung cancer cisplatin resistance cell line (A549/DDP) and the reversal mechanism of salvianolic acid A (SAA), a phenolic active compound extracted from Salvia miltiorrhiza. In this study, we found that A549/DDP cells exert up-regulation of c-met by activating the Akt/mTOR signaling pathway. We also show that SAA could increase the chemotherapeutic efficacy of cisplatin, suggesting a synergistic effect of SAA and cisplatin. Moreover, we revealed that SAA enhanced sensitivity to cisplatin in A549/DDP cells mainly through suppression of the c-met/AKT/mTOR signaling pathway. Knockdown of c-met revealed similar effects as that of SAA in A549/DDP cells. In addition, SAA effectively prevented multidrug resistance associated protein1 (MDR1) up-regulation in A549/DDP cells. Taken together, our results indicated that SAA suppressed c-met expression and enhanced the sensitivity of lung adenocarcinoma A549 cells to cisplatin through AKT/mTOR signaling pathway. Copyright © 2017 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

  2. Salvianolic acid A reverses cisplatin resistance in lung cancer A549 cells by targeting c-met and attenuating Akt/mTOR pathway

    Directory of Open Access Journals (Sweden)

    Xia-li Tang

    2017-09-01

    Full Text Available Drug resistance is one of the leading causes of chemotherapy failure in non-small cell lung cancer (NSCLC treatment. The purpose of this study was to investigate the role of c-met in human lung cancer cisplatin resistance cell line (A549/DDP and the reversal mechanism of salvianolic acid A (SAA, a phenolic active compound extracted from Salvia miltiorrhiza. In this study, we found that A549/DDP cells exert up-regulation of c-met by activating the Akt/mTOR signaling pathway. We also show that SAA could increase the chemotherapeutic efficacy of cisplatin, suggesting a synergistic effect of SAA and cisplatin. Moreover, we revealed that SAA enhanced sensitivity to cisplatin in A549/DDP cells mainly through suppression of the c-met/AKT/mTOR signaling pathway. Knockdown of c-met revealed similar effects as that of SAA in A549/DDP cells. In addition, SAA effectively prevented multidrug resistance associated protein1 (MDR1 up-regulation in A549/DDP cells. Taken together, our results indicated that SAA suppressed c-met expression and enhanced the sensitivity of lung adenocarcinoma A549 cells to cisplatin through AKT/mTOR signaling pathway.

  3. Valproic acid sensitizes metformin-resistant human renal cell carcinoma cells by upregulating H3 acetylation and EMT reversal.

    Science.gov (United States)

    Wei, Muyun; Mao, Shaowei; Lu, Guoliang; Li, Liang; Lan, Xiaopeng; Huang, Zhongxian; Chen, Yougen; Zhao, Miaoqing; Zhao, Yueran; Xia, Qinghua

    2018-04-17

    Metformin (Met) is a widely available diabetic drug and shows suppressed effects on renal cell carcinoma (RCC) metabolism and proliferation. Laboratory studies in RCC suggested that metformin has remarkable antitumor activities and seems to be a potential antitumor drug. But the facts that metformin may be not effective in reducing the risk of RCC in cancer clinical trials made it difficult to determine the benefits of metformin in RCC prevention and treatment. The mechanisms underlying the different conclusions between laboratory experiments and clinical analysis remains unclear. The goal of the present study was to determine whether long-term metformin use can induce resistance in RCC, whether metformin resistance could be used to explain the disaccord in laboratory and clinical studies, and whether the drug valproic acid (VPA), which inhibits histone deacetylase, exhibits synergistic cytotoxicity with metformin and can counteract the resistance of metformin in RCC. We performed CCK8, transwell, wound healing assay, flow cytometry and western blotting to detect the regulations of proliferation, migration, cell cycle and apoptosis in 786-O, ACHN and metformin resistance 786-O (786-M-R) cells treated with VPA, metformin or a combination of two drugs. We used TGF-β, SC79, LY294002, Rapamycin, protein kinase B (AKT) inhibitor to treat the 786-O or 786-M-R cells and detected the regulations in TGF-β /pSMAD3 and AMPK/AKT pathways. 786-M-R was refractory to metformin-induced antitumor effects on proliferation, migration, cell cycle and cell apoptosis. AMPK/AKT pathways and TGF-β/SMAD3 pathways showed low sensibilities in 786-M-R. The histone H3 acetylation diminished in the 786-M-R cells. However, the addition of VPA dramatically upregulated histone H3 acetylation, increased the sensibility of AKT and inhibited pSMAD3/SMAD4, letting the combination of VPA and metformin remarkably reappear the anti-tumour effects of metformin in 786-M-R cells. VPA not only exhibits

  4. 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

    International Nuclear Information System (INIS)

    Nakamura, Akiyoshi; Tamura, Noriko; Yasutake, Yoshiaki

    2015-01-01

    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

  5. 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.

  6. 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.

  7. Comparison of confinement in resistive-shell reversed-field pinch devices with two different magnetic shell penetration times

    International Nuclear Information System (INIS)

    Gravestijn, R M; Drake, J R; Hedqvist, A; Rachlew, E

    2004-01-01

    A loop voltage is required to sustain the reversed-field pinch (RFP) equilibrium. The configuration is characterized by redistribution of magnetic helicity but with the condition that the total helicity is maintained constant. The magnetic field shell penetration time, τ s , has a critical role in the stability and performance of the RFP. Confinement in the EXTRAP device has been studied with two values of τ s , first (EXTRAP-T2) with tau s of the order of the typical relaxation cycle timescale and then (EXTRAP-T2R) with τ s much longer than the relaxation cycle timescale, but still much shorter than the pulse length. Plasma parameters show significant improvements in confinement in EXTRAP-T2R. The typical loop voltage required to sustain comparable electron poloidal beta values is a factor of 3 lower in the EXTRAP-T2R device. The improvement is attributed to reduced magnetic turbulence

  8. Taurine zinc solid dispersions attenuate doxorubicin-induced hepatotoxicity and cardiotoxicity in rats

    International Nuclear Information System (INIS)

    Wang, Yu; Mei, Xueting; Yuan, Jingquan; Lu, Wenping; Li, Binglong; Xu, Donghui

    2015-01-01

    The clinical efficacy of anthracycline anti-neoplastic agents is limited by cardiac and hepatic toxicities. The aim of this study was to assess the hepatoprotective and cardioprotective effects of taurine zinc solid dispersions, which is a newly-synthesized taurine zinc compound, against doxorubicin-induced toxicity in Sprague–Dawley rats intraperitoneally injected with doxorubicin hydrochloride (3 mg/kg) three times a week (seven injections) over 28 days. Hemodynamic parameters, levels of liver toxicity markers and oxidative stress were assessed. Taurine zinc significantly attenuated the reductions in blood pressure, left ventricular pressure and ± dp/dtmax, increases in serum alanine aminotransferase and aspartate aminotransferase activities, and reductions in serum Zn 2+ and albumin levels (P < 0.05 or 0.01) induced by doxorubicin. In rats treated with doxorubicin, taurine zinc dose-dependently increased liver superoxide dismutase activity and glutathione concentration, and decreased malondialdehyde level (P < 0.01). qBase + was used to evaluate the stability of eight candidate reference genes for real-time quantitative reverse-transcription PCR. Taurine zinc dose-dependently increased liver heme oxygenase-1 and UDP-glucuronyl transferase mRNA and protein expression (P < 0.01). Western blotting demonstrated that taurine zinc inhibited c-Jun N-terminal kinase phosphorylation by upregulating dual-specificity phosphoprotein phosphatase-1. Additionally, taurine zinc inhibited cardiomyocyte apoptosis as there was decreased TUNEL/DAPI positivity and protein expression of caspase-3. These results indicate that taurine zinc solid dispersions prevent the side-effects of anthracycline-based anticancer therapy. The mechanisms might be associated with the enhancement of antioxidant defense system partly through activating transcription to synthesize endogenous phase II medicine enzymes and anti-apoptosis through inhibiting JNK phosphorylation. - Highlights:

  9. Taurine zinc solid dispersions attenuate doxorubicin-induced hepatotoxicity and cardiotoxicity in rats

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yu; Mei, Xueting; Yuan, Jingquan; Lu, Wenping; Li, Binglong; Xu, Donghui, E-mail: Donghuixu007@163.com

    2015-11-15

    The clinical efficacy of anthracycline anti-neoplastic agents is limited by cardiac and hepatic toxicities. The aim of this study was to assess the hepatoprotective and cardioprotective effects of taurine zinc solid dispersions, which is a newly-synthesized taurine zinc compound, against doxorubicin-induced toxicity in Sprague–Dawley rats intraperitoneally injected with doxorubicin hydrochloride (3 mg/kg) three times a week (seven injections) over 28 days. Hemodynamic parameters, levels of liver toxicity markers and oxidative stress were assessed. Taurine zinc significantly attenuated the reductions in blood pressure, left ventricular pressure and ± dp/dtmax, increases in serum alanine aminotransferase and aspartate aminotransferase activities, and reductions in serum Zn{sup 2+} and albumin levels (P < 0.05 or 0.01) induced by doxorubicin. In rats treated with doxorubicin, taurine zinc dose-dependently increased liver superoxide dismutase activity and glutathione concentration, and decreased malondialdehyde level (P < 0.01). qBase{sup +} was used to evaluate the stability of eight candidate reference genes for real-time quantitative reverse-transcription PCR. Taurine zinc dose-dependently increased liver heme oxygenase-1 and UDP-glucuronyl transferase mRNA and protein expression (P < 0.01). Western blotting demonstrated that taurine zinc inhibited c-Jun N-terminal kinase phosphorylation by upregulating dual-specificity phosphoprotein phosphatase-1. Additionally, taurine zinc inhibited cardiomyocyte apoptosis as there was decreased TUNEL/DAPI positivity and protein expression of caspase-3. These results indicate that taurine zinc solid dispersions prevent the side-effects of anthracycline-based anticancer therapy. The mechanisms might be associated with the enhancement of antioxidant defense system partly through activating transcription to synthesize endogenous phase II medicine enzymes and anti-apoptosis through inhibiting JNK phosphorylation. - Highlights:

  10. Chemotherapeutic Drugs and Mitochondrial Dysfunction: Focus on Doxorubicin, Trastuzumab, and Sunitinib

    Directory of Open Access Journals (Sweden)

    Stefania Gorini

    2018-01-01

    Full Text Available Many cancer therapies produce toxic side effects whose molecular mechanisms await full elucidation. The most feared and studied side effect of chemotherapeutic drugs is cardiotoxicity. Also, skeletal muscle physiology impairment has been recorded after many chemotherapeutical treatments. However, only doxorubicin has been extensively studied for its side effects on skeletal muscle. Chemotherapeutic-induced adverse side effects are, in many cases, mediated by mitochondrial damage. In particular, trastuzumab and sunitinib toxicity is mainly associated with mitochondria impairment and is mostly reversible. Vice versa, doxorubicin-induced toxicity not only includes mitochondria damage but can also lead to a more robust and extensive cell injury which is often irreversible and lethal. Drugs interfering with mitochondrial functionality determine the depletion of ATP reservoirs and lead to subsequent reversible contractile dysfunction. Mitochondrial damage includes the impairment of the respiratory chain and the loss of mitochondrial membrane potential with subsequent disruption of cellular energetic. In a context of increased stress, AMPK has a key role in maintaining energy homeostasis, and inhibition of the AMPK pathway is one of the proposed mechanisms possibly mediating mitochondrial toxicity due to chemotherapeutics. Therapies targeting and protecting cell metabolism and energy management might be useful tools in protecting muscular tissues against the toxicity induced by chemotherapeutic drugs.

  11. Role of fibronectin under conditions of doxorubicin action

    Directory of Open Access Journals (Sweden)

    A. I. Shevtsova

    2015-02-01

    Full Text Available There is no standard as to treatment of anthracycline chemotherapy complications. The reduction of cytotoxic drugs toxicity without weakening of their antitumor action remains relevant. The extracellular matrix which key component is fibronectin is present in all tissues and it continuously undergoes controlled remodeling. So, the purpose of our work was to study the level of fibronectin in the experimental model of doxorubicin-induced cardiomyopathy and effects of this cytostatic and its co-administration with antioxidants of different nature.The level of fibronectin was measured by ELISA using monospecific antibodies against fibronectin (Sigma, USA, secondary anti-IgG labeled with horseradish peroxidase (Sigma, USA and fibronectin standard (Sigma, USA. The study was conducted on Wistar male rats with weight of 210 ± 50 g which were divided into 4 groups by 8 animals in each group: 1 – control, rats receiving saline i/p; 2 – doxorubicin 1 mg/kg i/p once a week during 4 weeks; 3 – doxorubicin by the same scheme plus 1% 2-oxoglutarate in drinking water during 4 weeks;4 – doxorubicin by the same scheme and korvitin injection 30 min before doxorubicin application once a week during 4 weeks. Obtained data indicate the effect of doxorubicin to decrease in index mass heart in 38% of animals compared to control animals; decrease in total protein concentration by 8% (Р < 0,05 and increase of the level of fibronectin by 67% (P < 0,001 in blood plasma of rats and decrease in the level of fibronectin in the heart extract by 19% (Р < 0,05 under development of doxorubicin-induced cardiotoxicity. Increased fibronectin concentration in blood plasma had strong correlation with decreased total protein concentration in blood (r=0,80 and heart extract (r=0,59 in rats with doxorubicin-induced cardiomiophaty indicating the sensitive reaction of fibronectin to development of metabolic disorders under doxorubicin influence.

  12. 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.

  13. Use of cyclic current reversal polarization voltammetry for investigating the relationship between corrosion resistance and heat-treatment induced variations in microstructures of 400 C martensitic stainless steels

    Science.gov (United States)

    Ambrose, John R.

    1992-01-01

    Software for running a cyclic current reversal polarization voltammagram has been developed for use with a EG&G Princeton Applied Research Model 273 potentiostat/galvanostat system. The program, which controls the magnitude, direction and duration of an impressed galvanostatic current, will produce data in ASCII spreadsheets (Lotus, Quattro) for graphical representation of CCRPV voltammograms. The program was used to determine differences in corrosion resistance of 440 C martenstic stainless steel produced as a result of changes in microstructure effected by tempering. It was determined that tempering at all temperatures above 400 F resulted in increased polarizability of the material, with the increased likelihood that pitting would be initiated upon exposure to marine environments. These results will be used in development of remedial procedures for lowering the susceptibility of these alloys toward the stress corrosion cracking experienced in bearings used in high pressure oxygen turbopumps used in the main engines of space shuttle orbiters.

  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. CyclinG1 Amplification Enhances Aurora Kinase Inhibitor-Induced Polyploid Resistance and Inhibition of Bcl-2 Pathway Reverses the Resistance

    Directory of Open Access Journals (Sweden)

    Wenfeng Zhang

    2017-08-01

    Full Text Available Background/Aims: CyclinG1 (CycG1 is frequently overexpressed in solid tumors and overexpression of CycG1 promotes cell survival upon paclitaxel exposure by inducing polyploidy. Whether and how CycG1 regulates polyploidization caused by small molecular targeted inhibitors remains unclear. Methods: Immunohistochemistry and immunoblotting were utilized to examine protein expression. Cell proliferation was measured by ATPlite assay, and cell cycle distribution and apoptosis were measured by flow cytometry and/or DNA fragmentation assays. Results: Overexpression of CycG1 in breast cancer cells caused apoptosis-resistant polyploidy upon treatment with Aurora kinase inhibitor, ZM447439 (ZM. Addition of ABT-263, a small-molecule BH3 mimetic, to ZM, produced a synergistic loss of cell viability with greater sustained tumor growth inhibition in breast cancer cell lines. Decrease of Mcl-1 and increase of NOXA caused by ZM treatment, were responsible for the synergy. Furthermore, CycG1 was highly expressed in Triple-Negative-Breast-Cancer patients treated with paclitaxel and was paralleled by decreased cell survival. Conclusion: CycG1 is a crucial factor in ZM-induced polyploidy resistance, and ABT-263/ZM combination hold therapeutic utility in the CycG1-amplified subset of breast cancer and CycG1, thus, is a promising target in breast cancer.

  16. p21{sup WAF1/Cip1/Sdi1} knockout mice respond to doxorubicin with reduced cardiotoxicity

    Energy Technology Data Exchange (ETDEWEB)

    Terrand, Jerome; Xu, Beibei; Morrissy, Steve; Dinh, Thai Nho [Department of Pharmacology,College of Medicine, University of Arizona, 1501 N. Campbell Ave, Tucson, AZ 85724 (United States); Williams, Stuart [Biomedical Engineering Program, College of Medicine, University of Arizona, 1501 N. Campbell Ave, Tucson, AZ 85724 (United States); Chen, Qin M., E-mail: qchen@email.arizona.edu [Department of Pharmacology,College of Medicine, University of Arizona, 1501 N. Campbell Ave, Tucson, AZ 85724 (United States)

    2011-11-15

    Doxorubicin (Dox) is an antineoplastic agent that can cause cardiomyopathy in humans and experimental animals. As an inducer of reactive oxygen species and a DNA damaging agent, Dox causes elevated expression of p21{sup WAF1/Cip1/Sdi1} (p21) gene. Elevated levels of p21 mRNA and p21 protein have been detected in the myocardium of mice following Dox treatment. With chronic treatment of Dox, wild type (WT) animals develop cardiomyopathy evidenced by elongated nuclei, mitochondrial swelling, myofilamental disarray, reduced cardiac output, reduced ejection fraction, reduced left ventricular contractility, and elevated expression of ANF gene. In contrast, p21 knockout (p21KO) mice did not show significant changes in the same parameters in response to Dox treatment. In an effort to understand the mechanism of the resistance against Dox induced cardiomyopathy, we measured levels of antioxidant enzymes and found that p21KO mice did not contain elevated basal or inducible levels of glutathione peroxidase and catalase. Measurements of 6 circulating cytokines indicated elevation of IL-6, IL-12, IFN{gamma} and TNF{alpha} in Dox treated WT mice but not p21KO mice. Dox induced elevation of IL-6 mRNA was detected in the myocardium of WT mice but not p21KO mice. While the mechanism of the resistance against Dox induced cardiomyopathy remains unclear, lack of inflammatory response may contribute to the observed cardiac protection in p21KO mice. -- Highlights: Black-Right-Pointing-Pointer Doxorubicin induces p21 elevation in the myocardium. Black-Right-Pointing-Pointer Doxorubicin causes dilated cardiomyopathy in wild type mice. Black-Right-Pointing-Pointer p21 Knockout mice are resistant against doxorubicin induced cardiomyopathy. Black-Right-Pointing-Pointer Lack of inflammatory response correlates with the resistance in p21 knockout mice.

  17. Modulation of P-glycoprotein activity by novel synthetic curcumin derivatives in sensitive and multidrug-resistant T-cell acute lymphoblastic leukemia cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Ooko, Edna [Department of Pharmaceutical Biology, Institute of Pharmacy and Biochemistry, Johannes Gutenberg University, Staudinger Weg 5, 55128 Mainz (Germany); Alsalim, Tahseen; Saeed, Bahjat [Department of Chemistry, College of Education for Pure Sciences, University of Basrah, P.O. Box 49 Basrah, Al Basrah (Iraq); Saeed, Mohamed E.M.; Kadioglu, Onat [Department of Pharmaceutical Biology, Institute of Pharmacy and Biochemistry, Johannes Gutenberg University, Staudinger Weg 5, 55128 Mainz (Germany); Abbo, Hanna S. [Department of Chemistry, University of the Western Cape, P/B X17, Bellville, 7535 Cape Town (South Africa); Titinchi, Salam J.J., E-mail: stitinchi@uwc.ac.za [Department of Chemistry, University of the Western Cape, P/B X17, Bellville, 7535 Cape Town (South Africa); Efferth, Thomas, E-mail: efferth@uni-mainz.de [Department of Pharmaceutical Biology, Institute of Pharmacy and Biochemistry, Johannes Gutenberg University, Staudinger Weg 5, 55128 Mainz (Germany)

    2016-08-15

    Background: Multidrug resistance (MDR) and drug transporter P-glycoprotein (P-gp) represent major obstacles in cancer chemotherapy. We investigated 19 synthetic curcumin derivatives in drug-sensitive acute lymphoblastic CCRF–CEM leukemia cells and their multidrug-resistant P-gp-overexpressing subline, CEM/ADR5000. Material and methods: Cytotoxicity was tested by resazurin assays. Doxorubicin uptake was assessed by flow cytometry. Binding modes of compounds to P-gp were analyzed by molecular docking. Chemical features responsible for bioactivity were studied by quantitative structure activity relationship (QSAR) analyses. A 7-descriptor QSAR model was correlated with doxorubicin uptake values, IC{sub 50} values and binding energies. Results: The compounds displayed IC{sub 50} values between 0.7 ± 0.03 and 20.2 ± 0.25 μM. CEM/ADR5000 cells exhibited cross-resistance to 10 compounds, collateral sensitivity to three compounds and regular sensitivity to the remaining six curcumins. Molecular docking studies at the intra-channel transmembrane domain of human P-gp resulted in lowest binding energies ranging from − 9.00 ± 0.10 to − 6.20 ± 0.02 kcal/mol and pKi values from 0.24 ± 0.04 to 29.17 ± 0.88 μM. At the ATP-binding site of P-gp, lowest binding energies ranged from − 9.78 ± 0.17 to − 6.79 ± 0.01 kcal/mol and pKi values from 0.07 ± 0.02 to 0.03 ± 0.03 μM. CEM/ADR5000 cells accumulated approximately 4-fold less doxorubicin than CCRF–CEM cells. The control P-gp inhibitor, verapamil, partially increased doxorubicin uptake in CEM/ADR5000 cells. Six curcumins increased doxorubicin uptake in resistant cells or even exceeded uptake levels compared to sensitive one. QSAR yielded good activity prediction (R = 0.797 and R = 0.794 for training and test sets). Conclusion: Selected derivatives may serve to guide future design of novel P-gp inhibitors and collateral sensitive drugs to combat MDR. - Highlights: • Novel derivatives of curcumin in reversing

  18. Modulation of P-glycoprotein activity by novel synthetic curcumin derivatives in sensitive and multidrug-resistant T-cell acute lymphoblastic leukemia cell lines

    International Nuclear Information System (INIS)

    Ooko, Edna; Alsalim, Tahseen; Saeed, Bahjat; Saeed, Mohamed E.M.; Kadioglu, Onat; Abbo, Hanna S.; Titinchi, Salam J.J.; Efferth, Thomas

    2016-01-01

    Background: Multidrug resistance (MDR) and drug transporter P-glycoprotein (P-gp) represent major obstacles in cancer chemotherapy. We investigated 19 synthetic curcumin derivatives in drug-sensitive acute lymphoblastic CCRF–CEM leukemia cells and their multidrug-resistant P-gp-overexpressing subline, CEM/ADR5000. Material and methods: Cytotoxicity was tested by resazurin assays. Doxorubicin uptake was assessed by flow cytometry. Binding modes of compounds to P-gp were analyzed by molecular docking. Chemical features responsible for bioactivity were studied by quantitative structure activity relationship (QSAR) analyses. A 7-descriptor QSAR model was correlated with doxorubicin uptake values, IC 50 values and binding energies. Results: The compounds displayed IC 50 values between 0.7 ± 0.03 and 20.2 ± 0.25 μM. CEM/ADR5000 cells exhibited cross-resistance to 10 compounds, collateral sensitivity to three compounds and regular sensitivity to the remaining six curcumins. Molecular docking studies at the intra-channel transmembrane domain of human P-gp resulted in lowest binding energies ranging from − 9.00 ± 0.10 to − 6.20 ± 0.02 kcal/mol and pKi values from 0.24 ± 0.04 to 29.17 ± 0.88 μM. At the ATP-binding site of P-gp, lowest binding energies ranged from − 9.78 ± 0.17 to − 6.79 ± 0.01 kcal/mol and pKi values from 0.07 ± 0.02 to 0.03 ± 0.03 μM. CEM/ADR5000 cells accumulated approximately 4-fold less doxorubicin than CCRF–CEM cells. The control P-gp inhibitor, verapamil, partially increased doxorubicin uptake in CEM/ADR5000 cells. Six curcumins increased doxorubicin uptake in resistant cells or even exceeded uptake levels compared to sensitive one. QSAR yielded good activity prediction (R = 0.797 and R = 0.794 for training and test sets). Conclusion: Selected derivatives may serve to guide future design of novel P-gp inhibitors and collateral sensitive drugs to combat MDR. - Highlights: • Novel derivatives of curcumin in reversing multidrug

  19. Taking aim at a moving target: designing drugs to inhibit drug-resistant HIV-1 reverse transcriptases.

    Science.gov (United States)

    Sarafianos, Stefan G; Das, Kalyan; Hughes, Stephen H; Arnold, Eddy

    2004-12-01

    HIV undergoes rapid genetic variation; this variation is caused primarily by the enormous number of viruses produced daily in an infected individual. Because of this variation, HIV presents a moving target for drug and vaccine development. The variation within individuals has led to the generation of diverse HIV-1 subtypes, which further complicates the development of effective drugs and vaccines. In general, it is more difficult to hit a moving target than a stationary target. Two broad strategies for hitting a moving target (in this case, HIV replication) are to understand the movement and to aim at the portions that move the least. In the case of anti-HIV drug development, the first option can be addressed by understanding the mechanism(s) of drug resistance and developing drugs that effectively inhibit mutant viruses. The second can be addressed by designing drugs that interact with portions of the viral machinery that are evolutionarily conserved, such as enzyme active sites.

  20. Biotin-Pt (IV)-indomethacin hybrid: A targeting anticancer prodrug providing enhanced cancer cellular uptake and reversing cisplatin resistance.

    Science.gov (United States)

    Hu, Weiwei; Fang, Lei; Hua, Wuyang; Gou, Shaohua

    2017-10-01

    A Pt(IV) prodrug (2) composed of cancer-targeting biotin and nonsteroidal anti-inflammatory drug indomethacin in the axial positions of the six-coordinated octahedral geometry derived from cisplatin was developed, which could be highly accumulated in cancer cells more than normal ones and activated by endogenous reducing molecules to release cisplatin and indomethacin moieties simultaneously to inhibit tumor progression synergistically. In vitro assays revealed that 2 exhibited significantly selective inhibition to the tested cancer cell lines and sensitivity to cisplatin resistant cancer cells. Moreover, 2 presented cyclooxygenases inhibition properties to reduce tumor-associated inflammation, reduced the invasiveness of the highly aggressive PC-3 cells, and disrupted capillary-like tube formation in EA.hy926 cells. In all, this study offers a new strategy to enhance sensitivity and reduce toxicity of cisplatin. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Putative supramolecular complexes formed by carotenoids and xanthophylls with ascorbic acid to reverse multidrug resistance in cancer cells.

    Science.gov (United States)

    Molnár, József; Serly, Julianna; Pusztai, Rozália; Vincze, Irén; Molnár, Péter; Horváth, Györgyi; Deli, József; Maoka, Takashi; Zalatnai, Attila; Tokuda, Harukuni; Nishino, Hoyoku

    2012-02-01

    The molecular basis of interaction of selected carotenoids and xanthophylls with ascorbic acid on cancer cells was studied to determine their anticancer effects. Drug accumulation was measured in a human ABCB1 gene-transfected mouse lymphoma cell line and in a human lung cancer cell line by flow cytometry; furthermore, their anticancer effects were determined in mice in vivo. Several carotenoids inhibited the multidrug resistance of cancer cells. Ascorbic acid improved the effect of certain xanthophylls, but the effect of capsanthin was not modified. Capsanthin had weak (12%) but capsorubin (85%) had a remarkable antiproliferative effect on A549 lung cancer cells. Capsorubin reduced immediate-early tumor antigen expression, while capsanthin was not effective. Capsorubin accumulates selectively in the nuclei of cancer cells. The Authors suggest a special complex formation between membrane-bound capsorubin and ascorbic acid, which can be exploited in experimental chemotherapy.

  2. 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.

  3. Metabolic remodeling associated with subchronic doxorubicin cardiomyopathy

    International Nuclear Information System (INIS)

    Carvalho, Rui A.; Sousa, Rui P.B.; Cadete, Virgilio J.J.; Lopaschuk, Gary D.; Palmeira, Carlos M.M.; Bjork, James A.; Wallace, Kendall B.

    2010-01-01

    Doxorubicin (Adriamycin ® ) is a potent and broad-spectrum antineoplastic agent, the clinical utility of which is restricted by a cumulative and progressive cardiomyopathy that develops with repeated dosing. Fundamental to the cardiac failure is an interference with mitochondrial respiration and inhibition of oxidative phosphorylation. Global gene expression arrays in cardiac tissue indicate that inhibition of mitochondrial oxidative phosphorylation by doxorubicin (DOX) is accompanied by a decreased expression of genes related to aerobic fatty acid oxidation and a corresponding increase in expression of genes involved in anaerobic glycolysis, possibly as an alternate source for ATP production. The aim of this investigation was to determine whether this is also manifest at the metabonomic level as a switch in metabolic flux in cardiac tissue, and whether this can be averted by co-administering the cardioprotective drug, dexrazoxane (DZR). 13 C-isotopomer analysis of isolated perfused hearts from male Sprague-Dawley rats receiving 6 weekly s.c. injections of 2 mg/kg DOX demonstrated a shift from the preferential oxidation of fatty acids to enhanced oxidation of glucose and lactate plus pyruvate, indicative of a compensatory shift towards increased pyruvate dehydrogenase activity. Substrate-selective isotopomer analysis combined with western blots indicate an inhibition of long-chain fatty acid oxidation and not MCAD activity or fatty acyl-carnitine transport. Co-administering DZR averted many treatment-related changes in cardiac substrate metabolism, consistent with DZR being an effective cardioprotective agent against DOX-induced cardiomyopathy. This switch in substrate metabolism resembles that described for other models of cardiac failure; accordingly, this change in metabolic flux may represent a general compensatory response of cardiac tissue to imbalances in bioenergetic demand and supply, and not a characteristic unique to DOX-induced cardiac failure itself.

  4. Doxorubicin Action on Mitochondria: Relevance to Osteosarcoma Therapy?

    Science.gov (United States)

    Armstrong, Jo; Dass, Crispin R

    2018-01-01

    The mitochondria may very well determine the final commitment of the cell to death, particularly in times of energy stress. Cancer chemotherapeutics such as the anthracycline doxorubicin perturb mitochondrial structure and function in tumour cells, as evidenced in osteosarcoma, for which doxorubicin is used clinically as frontline therapy. This same mechanism of cell inhibition is also pertinent to doxorubicin's primary cause of side-effects, that to the cardiac tissue, culminating in such dire events as congestive heart failure. Reactive oxygen species are partly to blame for this effect on the mitochondria, which impact the electron transport chain. As this review highlights that, there is much more to be learnt about the mitochondria and how it is affected by such effective but toxic drugs as doxorubicin. Such information will aid researchers who search for cancer treatment able to preserve mitochondrial number and function in normal cells. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

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

    African Journals Online (AJOL)

    SUBASHINI

    2013-12-04

    Dec 4, 2013 ... Key words: Nardostachys jatamansi, doxorubicin, cytokine, glutathione, .... hoc test LSD, *P < 0.05, (Comparisons: control vs DOX induced group; DOX induced group vs NJ ... Figure 2 A-D shows the histological pictures of the.

  6. Mangifera indica L. leaf extract alleviates doxorubicin induced cardiac stress

    Directory of Open Access Journals (Sweden)

    Laxit Bhatt

    2017-09-01

    Conclusion: The present findings clearly suggest the protective role of alcoholic leaf extract of M. indica against oxidative stress induced by doxorubicin. [J Complement Med Res 2017; 6(3.000: 284-289

  7. Kaposi's sarcoma: Good outcome with doxorubicin, bleomycin and ...

    African Journals Online (AJOL)

    KS) in children in low-income countries. 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 ...

  8. 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...

  9. Histopathological effects of doxorubicin on kidneys in rats

    Directory of Open Access Journals (Sweden)

    I.A. Ali

    2014-06-01

    Full Text Available The aim of this study was to investigate the histolopathological effect of doxorubicin on rat kidney tissue. The drug was administrated by rats at the dose of (1, 2, 3, 4, 5 mg/kg intrapertonial every (84 hr for the three weeks and the doses of (1, 2, 3 mg/kg intrapertonial every 84 hrs for six weeks. The animals were scarified after 48 hr. of last injection. The study revealed congestion, thrombus, blood vessels hemorrhage, vaculation in the cells of glomerular tuft and tubular, tubuo-interstitial degeneration, tubular casts. The injury score revealed significantly increasing in the degree of injury in glomerules in the animals that received 5 mg/kg of doxorubicin for three weeks and also significantly increasing in the degree of injury in glomerules of the animals that received 3 mg/kg of doxorubicin for six weeks as compared with control animals. We concluded that the doxorubicin has histopathological effect on kidney.

  10. The overexpression and nuclear translocation of Trx-1 during hypoxia confers on HepG2 cells resistance to DDP, and GL-V9 reverses the resistance by suppressing the Trx-1/Ref-1 axis.

    Science.gov (United States)

    Zhao, Li; Li, Wei; Zhou, Yuxin; Zhang, Yi; Huang, Shaoliang; Xu, Xuefen; Li, Zhiyu; Guo, Qinglong

    2015-05-01

    Microenvironmental hypoxia gives many tumor cells the capacity for drug resistance. Thioredoxin family members play critical roles in the regulation of cellular redox homeostasis in a stressed environment. In this study, we established a hypoxia-drug resistance (hypoxia-DR) model using HepG2 cells and discovered that the overexpression and nuclear translocation of thioredoxin-1 (Trx-1) are closely associated with this resistance through the regulation of the metabolism by the oxidative stress response to glycolysis. Intranuclear Trx-1 enhances the DNA-binding activity of HIF-1α via its interaction with and reducing action on Ref-1, resulting in increased expression of glycolysis-related proteins (PDHK1, HKII, and LDHA), glucose uptake, and lactate generation under hypoxia. Meanwhile, we found that GL-V9, a newly synthesized flavonoid derivative, shows an ability to reverse the hypoxia-DR and has low toxicity both in vivo and in vitro. GL-V9 could inhibit the expression and nuclear translocation of Trx-1 and then suppress HIF-1α DNA-binding activity by inhibiting the Trx-1/Ref-1 axis. As a result, glycolysis is weakened and oxidative phosphorylation is enhanced. Thus, GL-V9 leads to an increment in intracellular ROS generation and consequently intensified apoptosis induced by DDP. Copyright © 2015 Elsevier Inc. All rights reserved.

  11. 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.

  12. Reversal of multidrug resistance by magnetic Fe3O4 nanoparticle copolymerizating daunorubicin and 5-bromotetrandrine in xenograft nude-mice.

    Science.gov (United States)

    Chen, Baoan; Cheng, Jian; Wu, Yanan; Gao, Feng; Xu, Wenlin; Shen, Huilin; Ding, Jiahua; Gao, Chong; Sun, Qian; Sun, Xinchen; Cheng, Hongyan; Li, Guohong; Chen, Wenji; Chen, Ningna; Liu, Lijie; Li, Xiaomao; Wang, Xuemei

    2009-01-01

    In this paper we establish the xenograft leukemia model with stable multidrug resistance in nude mice and to investigate the reversal effect of 5-bromotetrandrine (5-BrTet) and magnetic nanoparticle of Fe(3)O(4) (MNP-Fe(3)O(4)) combined with daunorubicin (DNR) in vivo. Two subclones of K562 and K562/A02 cells were inoculated subcutaneously into the back of athymic nude mice (1 x 10(7) cells/each) respectively to establish leukemia xenograft models. Drug-resistant and sensitive tumor-bearing nude mice were assigned randomly into five groups which were treated with normal saline; DNR; NP-Fe(3)O(4) combined with DNR; 5-BrTet combined with DNR; 5-BrTet and MNP-Fe(3)O(4) combined with DNR, respectively. The incidence of formation, growth characteristics, weight, and volume of tumors were observed. The histopathologic examination of tumors and organs were detected. For resistant tumors, the protein levels of Bcl-2, and BAX were detected by Western blot. Bcl-2, BAX, and caspase-3 genes were also detected. For K562/A02 cells xenograft tumors, 5-BrTet and MNP-Fe(3)O(4) combined with DNR significantly suppressed growth of tumor. A histopathologic examination of tumors clearly showed necrosis of the tumors. Application of 5-BrTet and MNP-Fe(3)O(4) inhibited the expression of Bcl-2 protein and upregulated the expression of BAX and caspase-3 proteins in K562/A02 cells xenograft tumor. It is concluded that 5-BrTet and MNP-Fe(3)O(4) combined with DNR had a significant tumor-suppressing effect on a MDR leukemia cells xenograft model.

  13. Reversal of multidrug resistance in xenograft nude-mice by magnetic Fe(3)O(4) nanoparticles combined with daunorubicin and 5-bromotetrandrine.

    Science.gov (United States)

    Wu, Ya-Nan; Chen, Bao-An; Cheng, Jian; Gao, Feng; Xu, Wen-Lin; Ding, Jia-Hua; Gao, Chong; Sun, Xin-Chen; Li, Guo-Hong; Chen, Wen-Ji; Liu, Li-Jie; Li, Xiao-Mao; Wang, Xue-Mei

    2009-02-01

    This study was aimed to investigate the reversal effect of 5-bromotetrandrine (5-BrTet) and magnetic nanoparticle of Fe(3)O(4) (Fe(3)O(4)-MNPs) combined with DNR in vivo. The xenograft leukemia model with stable multiple drug resistance in nude mice was established. The two sub-clones of K562 and K562/A02 cells were respectively inoculated subcutaneously into back of athymic nude mice (1 x 10(7) cells/each) to establish the leukemia xenograft models. Drug resistant and the sensitive tumor-bearing nude mice were both assigned randomly into 5 groups: group A was treated with NS; group B was treated with DNR; group C was treated with nanoparticle of Fe(3)O(4) combined with DNR; group D was treated with 5-BrTet combined with DNR; group E was treated with 5-bromotetrandrine and magnetic nanoparticle of Fe(3)O(4) combined with DNR. The incidence of tumor formation, growth characteristics, weight and volume of tumor were observed. The histopathologic examination of tumors and organs were carried out. The protein levels of BCL-2, BAX, and Caspase-3 in resistant tumors were detected by Western blot. The results indicated that 5-BrTet and magnetic nanoparticle of Fe(3)O(4) combined with DNR significantly suppressed growth of K562/A02 cell xenograft tumor, histopathologic examination of tumors showed the tumors necrosis obviously. Application of 5-BrTet and magnetic nanoparticle of Fe(3)O(4) inhibited the expression of BCL-2 protein and up-regulated the expression of BAX, and Caspase-3 protein in K562/A02 cell xenograft tumor. It is concluded that 5-bromotetrandrine and magnetic nanoparticle of Fe(3)O(4) combined with DNR have significant tumor-suppressing effect on MDR leukemia cell xenograft model.

  14. Hypoxic resistance of KRAS mutant tumor cells to 3-Bromopyruvate is counteracted by Prima-1 and reversed by N-acetylcysteine.

    Science.gov (United States)

    Orue, Andrea; Chavez, Valery; Strasberg-Rieber, Mary; Rieber, Manuel

    2016-11-18

    The metabolic inhibitor 3-bromopyruvate (3-BrPA) is a promising anti-cancer alkylating agent, shown to inhibit growth of some colorectal carcinoma with KRAS mutation. Recently, we demonstrated increased resistance to 3-BrPA in wt p53 tumor cells compared to those with p53 silencing or mutation. Since hypoxic microenvironments select for tumor cells with diminished therapeutic response, we investigated whether hypoxia unequally increases resistance to 3-BrPA in wt p53 MelJuso melanoma harbouring (Q61L)-mutant NRAS and wt BRAF, C8161 melanoma with (G12D)-mutant KRAS (G464E)-mutant BRAF, and A549 lung carcinoma with a KRAS (G12S)-mutation. Since hypoxia increases the toxicity of the p53 activator, Prima-1 against breast cancer cells irrespective of their p53 status, we also investigated whether Prima-1 reversed hypoxic resistance to 3-BrPA. In contrast to the high susceptibility of hypoxic mutant NRAS MelJuso cells to 3-BrPA or Prima-1, KRAS mutant C8161 and A549 cells revealed hypoxic resistance to 3-BrPA counteracted by Prima-1. In A549 cells, Prima-1 increased p21CDKN1mRNA, and reciprocally inhibited mRNA expression of the SLC2A1-GLUT1 glucose transporter-1 and ALDH1A1, gene linked to detoxification and stem cell properties. 3-BrPA lowered CAIX and VEGF mRNA expression. Death from joint Prima-1 and 3-BrPA treatment in KRAS mutant A549 and C8161 cells seemed mediated by potentiating oxidative stress, since it was antagonized by the anti-oxidant and glutathione precursor N-acetylcysteine. This report is the first to show that Prima-1 kills hypoxic wt p53 KRAS-mutant cells resistant to 3-BrPA, partly by decreasing GLUT-1 expression and exacerbating pro-oxidant stress.

  15. "US-detonated nano bombs" facilitate targeting treatment of resistant breast cancer.

    Science.gov (United States)

    Shi, Jinjin; Liu, Wei; Fu, Yu; Yin, Na; Zhang, Hongling; Chang, Junbiao; Zhang, Zhenzhong

    2018-03-28

    Reversal of drug resistance and targeted therapy are the keys but remain challenging in resistant breast cancer treatment. Herein, low frequency ultrasound detonated "nano bombs" were rationally designed and used for treatment of resistant breast cancer. For the 'nano bombs', the ammunition (Doxorubicin, DOX) was loaded into the ammunition depot (hollow mesoporous TiO 2 , MTNs), and the safety device (dsDNA) was wrapped on the surface of MTNs to avoid the unexpected DOX release. We found the "US-detonated explosive" abilities of "nano bomb" MTNs (NBMTNs), including explosive generation of ROS, explosive release of DOX, US-triggered lysosome escape and mitochondrial targeting in the in vitro and in vivo studies. More importantly, the drug resistance of MCF-7/ADR cells could be reversed via the inhibition of mitochondrial energy supply approach caused by the "explosion" of NBMTNs. Furthermore, NBMTNs combined the superior chemotherapy efficacy of DOX and potent SDT efficacy in one single platform and significantly enhanced the anticancer efficacy. Our results demonstrate an approach for reversing resistance and specific targeting of tumors using 'US-detonated nano bombs'. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Trichostatin A accentuates doxorubicin-induced hypertrophy in cardiac myocytes

    OpenAIRE

    Karagiannis, Tom C; Lin, Ann JE; Ververis, Katherine; Chang, Lisa; Tang, Michelle M; Okabe, Jun; El-Osta, Assam

    2010-01-01

    Histone deacetylase inhibitors represent a new class of anticancer therapeutics and the expectation is that they will be most effective when used in combination with conventional cancer therapies, such as the anthracycline, doxorubicin. The dose-limiting side effect of doxorubicin is severe cardiotoxicity and evaluation of the effects of combinations of the anthracycline with histone deacetylase inhibitors in relevant models is important. We used a well-established in vitro model of doxorubic...

  17. Echocardiographic changes in dogs long term treated with doxorubicin

    International Nuclear Information System (INIS)

    Silva, C.E.V.

    2005-01-01

    The doxorubicin's cardiotoxity was evaluated in seven clinically healthy adult dogs by means of intravenously injections of 30 mg/m2 of doxorubicin chloridate (Adriblastina), every 21 days, for 168 days (group A), performing a total cumulative dose of 240 mg/m2. Seven other dogs received 5 ml of 0.9% saline sterile solution intravenously (group B), following the protocol described above

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

    Science.gov (United States)

    2004-06-01

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

  19. 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.

  20. Reverse Algols

    Science.gov (United States)

    Leung, K. C.

    1989-01-01

    Reverse Algols, binary systems with a semidetached configuration in which the more massive component is in contact with the critical equipotential surface, are examined. Observational evidence for reverse Algols is presented and the parameters of seven reverse Algols are listed. The evolution of Algols and reverse Algols is discussed. It is suggested that, because reverse Algols represent the premass-reversal semidetached phase of close binary evolution, the evolutionary time scale between regular and reverse Algols is the ratio of the number of confirmed systems of these two Algol types.

  1. 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...

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

    Science.gov (United States)

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

    2016-01-01

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

  3. 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

  4. Multidrug resistance circumvention by a new triazinoaminopiperidine derivative S9788 in vitro: definition of the optimal schedule and comparison with verapamil.

    Science.gov (United States)

    Julia, A. M.; Roché, H.; Berlion, M.; Lucas, C.; Milano, G.; Robert, J.; Bizzari, J. P.; Canal, P.

    1994-01-01

    The current work was undertaken to investigate the importance of exposure sequence and duration in achieving the maximum reversal action of S9788 on doxorubicin (DOX) cytotoxicity against cells that exhibit the (MDR) multidrug resistance phenotype: the MCF7/DOX cell line. Accumulation and release of DOX were examined in this cell line. The reversal effect was compared with that obtained with verapamil. S9788 activity was schedule dependent: when comparing incubation with S9788 before or after treatment with DOX, the best reversal factor was obtained in the case of a post-treatment incubation (65.6 +/- 7.7 vs 20.8 +/- 7.0). S9788 was a more potent modulating agent than verapamil, whatever the schedule of exposure of the cells to the reversal agent. The reversal of resistance after short-term DOX exposures was caused not only by prolonged cellular accumulation of DOX, but also by its prolonged retention after transfer of cells to DOX-free medium. A relationship was noted between cellular exposure to DOX and the cytotoxic effect, and so the reversal of resistance induced by S9788 appears to be directly linked to the level of cell exposure to DOX. This work provided a rationale for improving the schedule of administration of S9788 in clinical trials. PMID:8180016

  5. 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

  6. Reversal of multidrug resistance by magnetic Fe3O4 nanoparticle copolymerizating daunorubicin and 5-bromotetrandrine in xenograft nude-mice

    Directory of Open Access Journals (Sweden)

    Baoan Chen

    2009-03-01

    Full Text Available Baoan Chen1,* Jian Cheng1,* Yanan Wu1, Feng Gao1, Wenlin Xu2, et al 1Department of Hematology;2Department of Hematology, The Affiliated People’s Hospital, Jiangsu University, Zhenjiang, PR China *These authors have contributed equally to this workAbstract: In this paper we establish the xenograft leukemia model with stable multidrug resistance in nude mice and to investigate the reversal effect of 5-bromotetrandrine (5-BrTet and magnetic nanoparticle of Fe3O4 (MNP-Fe3O4 combined with daunorubicin (DNR in vivo. Two subclones of K562 and K562/A02 cells were inoculated subcutaneously into the back of athymic nude mice (1 × 107 cells/each respectively to establish leukemia xenograft models. Drug-resistant and sensitive tumor-bearing nude mice were assigned randomly into five groups which were treated with normal saline; DNR; NP-Fe3O4 combined with DNR; 5-BrTet combined with DNR; 5-BrTet and MNP-Fe3O4 combined with DNR, respectively. The incidence of formation, growth characteristics, weight, and volume of tumors were observed. The histopathologic examination of tumors and organs were detected. For resistant tumors, the protein levels of Bcl-2, and BAX were detected by Western blot. Bcl-2, BAX, and caspase-3 genes were also detected. For K562/A02 cells xenograft tumors, 5-BrTet and MNP-Fe3O4 combined with DNR significantly suppressed growth of tumor. A histopathologic examination of tumors clearly showed necrosis of the tumors. Application of 5-BrTet and MNP-Fe3O4 inhibited the expression of Bcl-2 protein and upregulated the expression of BAX and caspase-3 proteins in K562/A02 cells xenograft tumor. It is concluded that 5-BrTet and MNP-Fe3O4 combined with DNR had a significant tumor-suppressing effect on a MDR leukemia cells xenograft model.Keywords: 5-bromotetrandrine, magnetic nanoparticle of Fe3O4, multidrug-resistance, xenograft model

  7. Nano-hole induction by nanodiamond and nanoplatinum liquid, DPV576, reverses multidrug resistance in human myeloid leukemia (HL60/AR

    Directory of Open Access Journals (Sweden)

    Ghoneum A

    2013-07-01

    Full Text Available Alia Ghoneum,1,2 Shivani Sharma,1,3 James Gimzewsk1,3 1Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, 2Department of Otalaryngology, Drew University of Medicine and Science, Los Angeles, 3California Nanosystems Institute (CNSI at University of California, Los Angeles, Los Angeles, CA, USA Abstract: Recently nanoparticles have been extensively studied and have proven to be a promising candidate for cancer treatment and diagnosis. In the current study, we examined the chemo-sensitizing activity of a mixture of nanodiamond (ND and nanoplatinum (NP solution known as DPV576, against multidrug-resistant (MDR human myeloid leukemia (HL60/AR and MDR-sensitive cells (HL60. Cancer cells were cultured with different concentrations of daunorubicin (DNR (1 × 10-9–1 × 10-6 M in the presence of selected concentrations of DPV576 (2.5%–10% v/v. Cancer cell survival was determined by MTT assay, drug accumulation by flow cytometry and confocal laser scanning microscopy (CLSM, and holes and structural changes by atomic force microscopy (AFM. Co-treatment of HL60/AR cells with DNR plus DPV576 resulted in the reduction of the IC50 to 1/4th. This was associated with increased incidences of holes inside the cells as compared with control untreated cells. On the other hand, HL60 cells did not show changes in their drug accumulation post-treatment with DPV576 and DNR. We conclude that DPV576 is an effective chemo-sensitizer as indicated by the reversal of HL60/AR cells to DNR and may represent a potential novel adjuvant for the treatment of chemo-resistant human myeloid leukemia. Keywords: nanodiamond, nanoplatinum, daunorubicin, flow cytometry, AFM

  8. Lovastatin induces apoptosis of ovarian cancer cells and synergizes with doxorubicin: potential therapeutic relevance

    International Nuclear Information System (INIS)

    Martirosyan, Anna; Clendening, James W; Goard, Carolyn A; Penn, Linda Z

    2010-01-01

    Ovarian carcinoma is a rarely curable disease, for which new treatment options are required. As agents that block HMG-CoA reductase and the mevalonate pathway, the statin family of drugs are used in the treatment of hypercholesterolemia and have been shown to trigger apoptosis in a tumor-specific manner. Recent clinical trials show that the addition of statins to traditional chemotherapeutic strategies can increase efficacy of targeting statin-sensitive tumors. Our goal was to assess statin-induced apoptosis of ovarian cancer cells, either alone or in combination with chemotherapeutics, and then determine these mechanisms of action. The effect of lovastatin on ovarian cancer cell lines was evaluated alone and in combination with cisplatin and doxorubicin using several assays (MTT, TUNEL, fixed PI, PARP cleavage) and synergy determined by evaluating the combination index. The mechanisms of action were evaluated using functional, molecular, and pharmacologic approaches. We demonstrate that lovastatin induces apoptosis of ovarian cancer cells in a p53-independent manner and synergizes with doxorubicin, a chemotherapeutic agent used to treat recurrent cases of ovarian cancer. Lovastatin drives ovarian tumor cell death by two mechanisms: first, by blocking HMG-CoA reductase activity, and second, by sensitizing multi-drug resistant cells to doxorubicin by a novel mevalonate-independent mechanism. This inhibition of drug transport, likely through inhibition of P-glycoprotein, potentiates both DNA damage and tumor cell apoptosis. The results of this research provide pre-clinical data to warrant further evaluation of statins as potential anti-cancer agents to treat ovarian carcinoma. Many statins are inexpensive, off-patent generic drugs that are immediately available for use as anti-cancer agents. We provide evidence that lovastatin triggers apoptosis of ovarian cancer cells as a single agent by a mevalonate-dependent mechanism. Moreover, we also show lovastatin synergizes

  9. 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

  10. Experimental and theoretical studies of active control of resistive wall mode growth in the EXTRAP T2R reversed-field pinch

    International Nuclear Information System (INIS)

    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.

    2005-01-01

    Active feedback control of resistive wall modes (RWMs) has been demonstrated on 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 (intelligent-shell) and cases where the feedback gain could be set for selected harmonics, with both real or complex values (targeted-harmonics). The growth of the dominant RWMs can be suppressed by feedback for both the intelligent-shell and targeted-harmonic control systems. Because the number of toroidal positions of saddle coils in the array is half the number of sensors, it is predicted and observed experimentally that the control harmonic spectrum has sidebands. As a result, each control harmonic has to control simultaneously two mode harmonics. Real gains can stabilize non-rotating RWMs, while complex gains give better results for (slowly) rotating RWMs. 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. (author)

  11. Reverse Osmosis

    Indian Academy of Sciences (India)

    many applications, one of which is desalination of seawater. The inaugural Nobel Prize in Chemistry was awarded in 1901 to van 't Hoff for his seminal work in this area. The present article explains the principle of osmosis and reverse osmosis. Osmosis and Reverse Osmosis. As the name suggests, reverse osmosis is the ...

  12. Trichostatin A accentuates doxorubicin-induced hypertrophy in cardiac myocytes.

    Science.gov (United States)

    Karagiannis, Tom C; Lin, Ann J E; Ververis, Katherine; Chang, Lisa; Tang, Michelle M; Okabe, Jun; El-Osta, Assam

    2010-10-01

    Histone deacetylase inhibitors represent a new class of anticancer therapeutics and the expectation is that they will be most effective when used in combination with conventional cancer therapies, such as the anthracycline, doxorubicin. The dose-limiting side effect of doxorubicin is severe cardiotoxicity and evaluation of the effects of combinations of the anthracycline with histone deacetylase inhibitors in relevant models is important. We used a well-established in vitro model of doxorubicin-induced hypertrophy to examine the effects of the prototypical histone deacetylase inhibitor, Trichostatin A. Our findings indicate that doxorubicin modulates the expression of the hypertrophy-associated genes, ventricular myosin light chain-2, the alpha isoform of myosin heavy chain and atrial natriuretic peptide, an effect which is augmented by Trichostatin A. Furthermore, we show that Trichostatin A amplifies doxorubicin-induced DNA double strand breaks, as assessed by γH2AX formation. More generally, our findings highlight the importance of investigating potential side effects that may be associated with emerging combination therapies for cancer.

  13. Synergistic and complete reversal of the multidrug resistance of mitoxantrone hydrochloride by three-in-one multifunctional lipid-sodium glycocholate nanocarriers based on simultaneous BCRP and Bcl-2 inhibition.

    Science.gov (United States)

    Ling, Guixia; Zhang, Tianhong; Zhang, Peng; Sun, Jin; He, Zhonggui

    Multidrug resistance (MDR) is a severe obstacle to successful chemotherapy due to its complicated nature that involves multiple mechanisms, such as drug efflux by transporters (P-glycoprotein and breast cancer resistance protein, BCRP) and anti-apoptotic defense (B-cell lymphoma, Bcl-2). To synergistically and completely reverse MDR by simultaneous inhibition of pump and non-pump cellular resistance, three-in-one multifunctional lipid-sodium glycocholate (GcNa) nanocarriers (TMLGNs) have been designed for controlled co-delivery of water-soluble cationic mitoxantrone hydrochloride (MTO), cyclosporine A (CsA - BCRP inhibitor), and GcNa (Bcl-2 inhibitor). GcNa and dextran sulfate were incorporated as anionic compounds to enhance the encapsulation efficiency of MTO (up to 97.8%±1.9%) and sustain the release of cationic MTO by electrostatic interaction. The results of a series of in vitro and in vivo investigations indicated that the TMLGNs were taken up by the resistant cancer cells by an endocytosis pathway that escaped the efflux induced by BCRP, and the simultaneous release of CsA with MTO further efficiently inhibited the efflux of the released MTO by BCRP; meanwhile GcNa induced the apoptosis process, and an associated synergistic antitumor activity and reversion of MDR were achieved because the reversal index was almost 1.0.

  14. TRB3 reverses chemotherapy resistance and mediates crosstalk between endoplasmic reticulum stress and AKT signaling pathways in MHCC97H human hepatocellular carcinoma cells.

    Science.gov (United States)

    Li, Yang; Zhu, Danxi; Hou, Lidan; Hu, Bin; Xu, Min; Meng, Xiangjun

    2018-01-01

    Tribbles homolog 3 (TRB3), a type of pseudokinase that contains a consensus serine/threonine kinase catalytic core structure, is upregulated in hepatocellular carcinoma. However, the effect of TRB3 expression in hepatocellular carcinoma and the molecular mechanisms underlying TRB3-mediated effects on tumorigenesis in hepatocellular carcinoma have not been fully elucidated. The present study focused on the effect of TRB3 expression in MHCC97H hepatocellular carcinoma cells and investigated the underlying molecular mechanisms in MHCC97H cells. In the present study, it was revealed that TRB3 was significantly overexpressed in the MHCC97H hepatocellular carcinoma cell compared with L-02 normal hepatic cells. Under endoplasmic reticulum (ER) stress induced by thapsigargin and tunicamycin, the levels of TRB3, CCAAT/enhancer binding protein homologous protein (CHOP), protein kinase B (AKT) and phosphorylated (p)AKT expression were upregulated. Furthermore, when the expression of TRB3 was silenced by short hairpin (sh)RNA, the survival of MHCC97H hepatocellular carcinoma cells was increased. Notably, following transduction with lentiviral containing TRB3-shRNA, cell survival also increased after treatment with chemotherapy drug cisplatin. The present study demonstrated that knockdown of CHOP by shRNA was able to reduce TRB3 expression, and the knockdown of TRB3 markedly increased the level of pAKT. TRB3 was overexpressed in MHCC97H hepatocellular carcinoma cells, particularly under endoplasmic reticulum stress. Knockdown of TRB3 was able to increase cell survival. Therefore, TRB3 expression may induce apoptosis and reverse resistance to chemotherapy in MHCC97H hepatic carcinoma cells. The present study suggests that TRB3 is a key molecule that mediates the crosstalk between ER stress and AKT signal pathways. Furthermore, the present study may provide further insight into the cancer biology of hepatocellular carcinoma and the development of anticancer drugs targeting the ER

  15. 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.

  16. Experimental and theoretical studies of active control of resistive wall mode growth in the EXTRAP T2R reversed-field pinch

    International Nuclear Information System (INIS)

    Drake, J.R.; Brunsell, P.R.; Yadikin, D.

    2005-01-01

    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

  17. RPAP3 enhances cytotoxicity of doxorubicin by impairing NF-kappa B pathway

    International Nuclear Information System (INIS)

    Shimada, Kana; Saeki, Makio; Egusa, Hiroshi; Fukuyasu, Sho; Yura, Yoshiaki; Iwai, Kazuhiro; Kamisaki, Yoshinori

    2011-01-01

    Research highlights: → RNA polymerase II-associated protein 3 (RPAP3) possesses an activity to bind with NEMO and to inhibit the ubiquitination of NEMO. → RPAP3 enhances doxorubicin-induced cell death in breast cancer cell line T-47D through the marked impairment of NF-κB pathway. → RPAP3 is a novel modulator of NF-κB pathway in apoptosis induced by anti-cancer chemotherapeutic agents. -- Abstract: Activation of anti-apoptotic gene transcription by NF-κB (nuclear factor-kappa B) has been reported to be linked with a resistance of cancer cells against chemotherapy. NEMO (NF-κB essential modulator) interacts with a number of proteins and modulates the activity of NF-κB pathway. In this study, we revealed that RPAP3 (RNA polymerase II-associated protein 3) possesses an activity to bind with NEMO and to inhibit the ubiquitination of NEMO and that RPAP3 enhances doxorubicin-induced cell death in breast cancer cell line T-47D through the marked impairment of NF-κB pathway. These results indicate that RPAP3 may be a novel modulator of NF-κB pathway in apoptosis induced by anti-cancer chemotherapeutic agents.

  18. Cytotoxicity and inhibitory properties against topoisomerase II of doxorubicin and its formamidine derivatives.

    Science.gov (United States)

    Kik, Krzysztof; Studzian, Kazimierz; Wasowska-Łukawska, Małgorzata; Oszczapowicz, Irena; Szmigiero, Leszek

    2009-01-01

    This work was undertaken to compare cytotoxicity, DNA damaging properties and effect on DNA cleavage by topoisomerase II of the anthracycline drug doxorubicin (DOX) and its two derivatives with a formamidino group containing a cyclic amine moiety such as morpholine (DOXM) or hexamethyleneimine (DOXH). The tetrazolium dye colorimetric assay was used to determine the cytotoxic activity of anthracyclines toward L1210 leukemia cells. DNA damage was measured by alkaline elution technique. The effect of anthracyclines on DNA cleavage was studied in a cell-free system containing supercoiled pBR322 DNA and purified human topoisomerase II. The cytotoxicity data and the results of studies on the mechanism of DNA break formation by anthracyclines at the cellular level and in the cell-free system showed that the presence of the formamidino group in the doxorubicin molecule reduced its ability to stimulate DNA cleavage by DNA topoisomerase II. DNA topoisomerase II is not a primary cellular target for DOXM or DOXH. An advantageous feature of formamidinoanthracyclines is their mechanism of cytotoxic action which is not related to the inhibition of DNA topoisomerase II. Therefore this class of anthracyclines seems to be a good source for selection of an anticancer drug directed toward cancer cells with the developed multidrug resistance attributed to the presence of altered DNA topoisomerase II.

  19. 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 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.

  20. 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.

  1. Protective effects of acute exercise prior to doxorubicin on cardiac function of breast cancer patients: A proof-of-concept RCT.

    Science.gov (United States)

    Kirkham, A A; Shave, R E; Bland, K A; Bovard, J M; Eves, N D; Gelmon, K A; McKenzie, D C; Virani, S A; Stöhr, E J; Warburton, D E R; Campbell, K L

    2017-10-15

    Preclinical studies have reported that a single treadmill session performed 24h prior to doxorubicin provides cardio-protection. We aimed to characterize the acute change in cardiac function following an initial doxorubicin treatment in humans and determine whether an exercise session performed 24h prior to treatment changes this response. Breast cancer patients were randomized to either 30min of vigorous-intensity exercise 24h prior to the first doxorubicin treatment (n=13), or no vigorous exercise for 72h prior to treatment (control, n=11). Echocardiographically-derived left ventricular volumes, longitudinal strain, twist, E/A ratio, and circulating NT-proBNP, a marker of later cardiotoxicity, were measured before and 24-48h after the treatment. Following treatment in the control group, NT-proBNP, end-diastolic and stroke volumes, cardiac output, E/A ratio, strain, diastolic strain rate, twist, and untwist velocity significantly increased (all p≤0.01). Whereas systemic vascular resistance (pvolume overload, and changes in longitudinal strain and twist opposite in direction to documented longer-term changes. An exercise session performed 24h prior to treatment attenuated NT-proBNP release and increased systolic function. Future investigations should verify these findings in a larger cohort and across multiple courses of doxorubicin. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Combined doxorubicin and paclitaxel in advanced breast cancer

    DEFF Research Database (Denmark)

    Gehl, J; Boesgaard, M; Paaske, T

    1996-01-01

    -550). The main toxicities were neutropenia, parestesia, nausea/vomiting, alopecia, myalgia and cardiotoxicity. Fifteen patients (50%) had reductions of left ventricular ejection fraction of below normal levels and 6 of these patients (20%) developed congestive heart failure. CONCLUSION: The combination...... of doxorubicin and paclitaxel is highly active, but is accompanied by the dose-limiting toxic effects of neutropenia, neuropathy and cardiotoxicity....

  3. The effect of HCV serological status on Doxorubicin based ...

    African Journals Online (AJOL)

    Background: Breast cancer and HCV are two frequent diseases in Egypt. There is a considerable probability of concurrent affection. This concurrence creates a subpopulation, which needs special evaluation and care. Objective: To evaluate a subset of Egyptian breast cancer patients receiving Doxorubicin based adjuvant ...

  4. 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. 

  5. 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 ...

  6. Antitumor activity of doxorubicine-loaded nanoemulsion against ...

    African Journals Online (AJOL)

    Pharmacotherapy Group, Faculty of Pharmacy, University of Benin, Benin City, 300001 Nigeria. All rights ... Keywords: Doxorubicine, Anti-tumor activity, Mean survival time, Heart histology, Nanoemulsion, Lipid profile .... the standard kit methods using fully Automated ..... effects of this new formulation in human patients.

  7. Chrysin enhances doxorubicin-induced cytotoxicity in human lung epithelial cancer cell lines: The role of glutathione

    Energy Technology Data Exchange (ETDEWEB)

    Brechbuhl, Heather M. [Pediatrics, National Jewish Health, Denver, Colorado (United States); Kachadourian, Remy; Min, Elysia [Department of Medicine, National Jewish Health, Denver, Colorado (United States); Chan, Daniel [Medical Oncology, University of Colorado Denver Health Sciences Center (United States); Day, Brian J., E-mail: dayb@njhealth.org [Department of Medicine, University of Colorado Denver Health Sciences Center (United States); Immunology, University of Colorado Denver Health Sciences Center (United States); Pharmaceutical Sciences, University of Colorado Denver Health Sciences Center (United States); Department of Medicine, National Jewish Health, Denver, Colorado (United States)

    2012-01-01

    We hypothesized that flavonoid-induced glutathione (GSH) efflux through multi-drug resistance proteins (MRPs) and subsequent intracellular GSH depletion is a viable mechanism to sensitize cancer cells to chemotherapies. This concept was demonstrated using chrysin (5–25 μM) induced GSH efflux in human non-small cell lung cancer lines exposed to the chemotherapeutic agent, doxorubicin (DOX). Treatment with chrysin resulted in significant and sustained intracellular GSH depletion and the GSH enzyme network in the four cancer cell types was predictive of the severity of chrysin induced intracellular GSH depletion. Gene expression data indicated a positive correlation between basal MRP1, MRP3 and MRP5 expression and total GSH efflux before and after chrysin exposure. Co-treating the cells for 72 h with chrysin (5–30 μM) and DOX (0.025–3.0 μM) significantly enhanced the sensitivity of the cells to DOX as compared to 72-hour DOX alone treatment in all four cell lines. The maximum decrease in the IC{sub 50} values of cells treated with DOX alone compared to co-treatment with chrysin and DOX was 43% in A549 cells, 47% in H157 and H1975 cells and 78% in H460 cells. Chrysin worked synergistically with DOX to induce cancer cell death. This approach could allow for use of lower concentrations and/or sensitize cancer cells to drugs that are typically resistant to therapy. -- Graphical abstract: Possible mechanisms by which chrysin enhances doxorubicin-induced toxicity in cancer cells. Highlights: ► Chyrsin sustains a significant depletion of GSH levels in lung cancer cells. ► Chyrsin synergistically potentiates doxorubicin-induced cancer cell cytotoxicity. ► Cancer cell sensitivity correlated with GSH and MRP gene network expression. ► This approach could allow for lower side effects and targeting resistant tumors.

  8. 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 both hippocampus-dependent spatial learning and learning a new target location within a familiar environment: reversal learning. A 6-d protocol was divided into the initial spatial learning phase (3.5 d) immediately followed by the reversal phase (2.5 d). During the 6 h following four or 12 training trials/day of initial or reversal learning phases, REM sleep was eliminated and non-REM sleep left intact using the multiple inverted flowerpot method. Contrary to our hypotheses, REM sleep deprivation during four or 12 trials/day of initial spatial or reversal learning did not affect training performance. However, some probe trial measures indicated REM sleep-deprivation–associated impairment in initial spatial learning with four trials/day and enhancement of subsequent reversal learning. In naive animals, REM sleep deprivation during normal initial spatial learning was followed by a lack of preference for the subsequent reversal platform location during the probe. Our findings contradict reports that REM sleep is essential for spatial learning in the Morris water maze and newly reveal that short periods of REM sleep deprivation do not impair concurrent reversal learning. Effects on subsequent reversal learning are consistent with the idea that REM sleep serves the consolidation of incompletely learned items. PMID:21677190

  9. Alpha-tocopheryl polyethylene glycol succinate-emulsified poly(lactic-co-glycolic acid) nanoparticles for reversal of multidrug resistance in vitro

    International Nuclear Information System (INIS)

    Wang Ying; Lu Yu; Ding Liying; Liu Yaqing; Yu Shuqin; Guo Miao; Ron Wenting; Song Feifei

    2012-01-01

    Multidrug resistance (MDR) is one of the factors in the failure of anticancer chemotherapy. In order to enhance the anticancer effect of P-glycoprotein (P-gp) substrates, inhibition of the P-gp efflux pump on MDR cells is a good tactic. We designed novel multifunctional drug-loaded alpha-tocopheryl polyethylene glycol succinate (TPGS)/poly(lactic-co-glycolic acid) (PLGA) nanoparticles (TPGS/PLGA/SN-38 NPs; SN-38 is 7-ethyl-10-hydroxy-camptothecin), with TPGS-emulsified PLGA NPs as the carrier and modulator of the P-gp efflux pump and SN-38 as the model drug. TPGS/PLGA/SN-38 NPs were prepared using a modified solvent extraction/evaporation method. Physicochemical characterizations of TPGS/PLGA/SN-38 NPs were in conformity with the principle of nano-drug delivery systems (nDDSs), including a diameter of about 200 nm, excellent spherical particles with a smooth surface, narrow size distribution, appropriate surface charge, and successful drug-loading into the NPs. The cytotoxicity of TPGS/PLGA/SN-38 NPs to MDR cells was increased by 3.56 times compared with that of free SN-38. Based on an intracellular accumulation study relative to the time-dependent uptake and efflux inhibition, we suggest novel mechanisms of MDR reversal of TPGS/PLGA NPs. Firstly, TPGS/PLGA/SN-38 NPs improved the uptake of the loaded drug by clathrin-mediated endocytosis in the form of unbroken NPs. Simultaneously, intracellular NPs escaped the recognition of P-gp by MDR cells. After SN-38 was released from TPGS/PLGA/SN-38 NPs in MDR cells, TPGS or/and PLGA may modulate the efflux microenvironment of the P-gp pump, such as mitochondria and the P-gp domain with an ATP-binding site. Finally, the controlled-release drug entered the nucleus of the MDR cell to induce cytotoxicity. The present study showed that TPGS-emulsified PLGA NPs could be functional carriers in nDDS for anticancer drugs that are also P-gp substrates. More importantly, to enhance the therapeutic effect of P-gp substrates, this work

  10. 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

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

    Science.gov (United States)

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

    2014-01-01

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

  12. GSH-targeted nanosponges increase doxorubicin-induced toxicity "in vitro" and "in vivo" in cancer cells with high antioxidant defenses.

    Science.gov (United States)

    Daga, Martina; Ullio, Chiara; Argenziano, Monica; Dianzani, Chiara; Cavalli, Roberta; Trotta, Francesco; Ferretti, Carlo; Zara, Gian Paolo; Gigliotti, Casimiro L; Ciamporcero, Eric S; Pettazzoni, Piergiorgio; Corti, Denise; Pizzimenti, Stefania; Barrera, Giuseppina

    2016-08-01

    Several reports indicate that chemo-resistant cancer cells become highly adapted to intrinsic oxidative stress by up-regulating their antioxidant systems, which causes an increase of intracellular GSH content. Doxorubicin is one of the most widely used drugs for tumor treatment, able to kill cancer cells through several mechanisms. However, doxorubicin use is limited by its toxicity and cancer resistance. Therefore, new therapeutic strategies able to reduce doses and to overcome chemo-resistance are needed. A new class of glutathione-responsive cyclodextrin nanosponges (GSH-NS), is able to release anticancer drugs preferentially in cells having high GSH content. Doxorubicin-loaded GSH-NS, in the cancer cells with high GSH content, inhibited clonogenic growth, cell viability, topoisomerase II activity and induced DNA damage with higher effectiveness than free drug. Moreover, GSH-NS reduced the development of human tumor in xenograft models more than free drug. These characteristics indicate that GSH-NS can be a suitable drug delivery carrier for future applications in cancer therapy. Copyright © 2016 Elsevier Inc. All rights reserved.

  13. 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.

  14. Preparation and characteristics of lipid nanoemulsion formulations loaded with doxorubicin

    Directory of Open Access Journals (Sweden)

    Jiang SP

    2013-08-01

    Full Text Available Sai-Ping Jiang,1,2,* Sai-Nan He,3,* Yun-Long Li,2,3 Da-Lin Feng,2 Xiao-Yang Lu,1 Yong-Zhong Du,2 He-Yong Yu,3 Fu-Qiang Hu,2 Hong Yuan2 1Department of Pharmacy, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, 2College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, 3Women's Hospital, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China *These authors contributed equally to this work Purpose: Safe and effective lipid nanoemulsion (LNE formulations for the antitumor delivery of doxorubicin is designed. Methods: LNEs composed of medium-chain triglyceride, soybean oil, lecithin, and doxorubicin are prepared by a solvent-diffusion method in an aqueous system. The effects of lipid material composition and polyethylene glycol (PEGylation on the size, drug encapsulation efficiency, and stability of LNEs are investigated. Based on in-vitro cytotoxicity and cellular uptake tests of A549 (human lung carcinoma cells, in-vivo biodistribution, antitumor activity, and cardiac toxicity are further examined using nude mouse bearing A549 tumor. Results: The LNE size decreases from 126.4 ± 8.7 nm to 44.5 ± 9.3 nm with increased weight ratio of medium-chain triglyceride to soybean oil from 1:4 to 3:2, whereas the encapsulation efficiency of doxorubicin is slightly reduced from 79.2% ± 2.1% to 71.2% ± 2.9%. The PEGylation of LNE by 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[carboxy(PEG2000] (DSPE-PEG 2000 does not significantly change the size and drug encapsulation efficiency. Three-month storage at room temperature and lyophilization process does not affect the drug encapsulation efficiency, whereas the size slightly increases to almost 100 nm. The in-vitro drug-release profiles of LNEs suggest that the present formulation can prolong drug release for 48 hours. LNEs can be internalized into tumor cells in vitro and efficiently accumulate in tumor tissues in vivo by passive targeting

  15. 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.

  16. Antioxidant Activities of Celery and Parsley Juices in Rats Treated with Doxorubicin

    Directory of Open Access Journals (Sweden)

    Svetlana Trivic

    2010-09-01

    Full Text Available We have examined the influence of diluted pure celery and parsley leaf and root juices and their combinations with doxorubicin on the antioxidant status [as measured by the content of reduced glutathione (GSH and ferric reducing antioxidant power (FRAP] in liver homogenate and hemolysate and on the contents of cytochrome P450 in liver homogenate. It was found that doxorubicin significantly decreased the content of reduced glutathione and the total antioxidative status (FRAP in liver homogenate and hemolysate, while celery and parsley juices alone and in combination with doxorubicin had different actions. Doxorubicin and celery juice had no effect on content of cytochrome P450. However, in combination with doxorubicin, parsley root juice significant increased, and parsley leaves juice decreased the cytochrome P450 content (compared to doxorubicin treated animals. Only parsley root juice significantly increased the content of cytochrome P450.

  17. Antioxidant activities of celery and parsley juices in rats treated with doxorubicin.

    Science.gov (United States)

    Kolarovic, Jovanka; Popovic, Mira; Zlinská, Janka; Trivic, Svetlana; Vojnovic, Matilda

    2010-09-03

    We have examined the influence of diluted pure celery and parsley leaf and root juices and their combinations with doxorubicin on the antioxidant status [as measured by the content of reduced glutathione (GSH) and ferric reducing antioxidant power (FRAP)] in liver homogenate and hemolysate and on the contents of cytochrome P450 in liver homogenate. It was found that doxorubicin significantly decreased the content of reduced glutathione and the total antioxidative status (FRAP) in liver homogenate and hemolysate, while celery and parsley juices alone and in combination with doxorubicin had different actions. Doxorubicin and celery juice had no effect on content of cytochrome P450. However, in combination with doxorubicin, parsley root juice significant increased, and parsley leaves juice decreased the cytochrome P450 content (compared to doxorubicin treated animals). Only parsley root juice significantly increased the content of cytochrome P450.

  18. Minoxidil (Mx) as a prophylaxis of doxorubicin--induced alopecia.

    Science.gov (United States)

    Rodriguez, R; Machiavelli, M; Leone, B; Romero, A; Cuevas, M A; Langhi, M; Romero Acuña, L; Romero Acuña, J; Amato, S; Barbieri, M

    1994-10-01

    Minoxidil (Mx) is known to induce hair growth in men with male-pattern baldness. Based on this potential, the effectiveness of Mx 2% topical solution was evaluated in cancer patients (pts) to prevent doxorubicin-induced alopecia. 48 female pts with different types of solid tumors treated with doxorubicin-based chemotherapy in a dose range of 50-60 mg/m2/cycle were randomly assigned to receive Mx 2% topical solution or placebo. 88% and 92% of pts in both arms showed severe alopecia (p = ns). No adverse effects were observed. In this study Mx 2% topical solution was non-toxic but was not effective in the prevention of chemotherapy-induced alopecia.

  19. 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.

  20. A fish oil diet does not reverse insulin resistance despite decreased adipose tissue TNF-alpha protein concentration in ApoE-3*Leiden mice

    NARCIS (Netherlands)

    Muurling, Martin; Mensink, Ronald P.; Pijl, Hanno; Romijn, Johannes A.; Havekes, Louis M.; Voshol, Peter J.

    2003-01-01

    Dietary interventions with fish oil have been found to protect against the development of high-fat diet-induced insulin resistance and to decrease the expression of tumor necrosis factor (TNF)-alpha. However, the effect of fish oil administration on preexisting insulin resistance is subject to

  1. Serial exercise gated radionuclide ventriculograms (RVG) in monitoring doxorubicin cardiotoxicity

    International Nuclear Information System (INIS)

    Goldstein, H.A.; Lahoda, J.; Fox, L.

    1985-01-01

    The resting RVG (Radionuclide Ventriculograms) are demonstrated to be an effective monitor of the cardiotoxicity of doxorubicin. The exercise RVG has not been as well studied to see if it yields additional information or detects toxicity effects earlier. Sixteen patients receiving doxorubicin for chemotherapy had 2-6 serial exercise studies with intervals between studies of 1 month to 15 months. The patients exercised varying amounts with cardiac work indicated by their double products (HR x Sys. BP). Although all patients started with a normal resting LVEF (>50%), 5 of the 16 did not have a normal response (≥5% increase in LVEF) with initial exercise study. Of the 11 patients with an initially normal response to exercise, on at least one subsequent study, 3 had an abnormal response to exercise. On a later follow up study 1 of these 3 patients again had a normal response to exercise. Six of these 11 patients had had RVG evidence of cardiotoxicity. Four of these 6 patients had continually normal exercise responses, while 2 of these 5 patients had had an abnormal exercise response. An initial exercise RVG may be reasonable to detect unsuspected CAD in cancer victims. These patients are reported to be more sensitive to the toxic effects of doxorubicin. Follow up exercise RVGs do not contribute useful information, do not predict cardiotoxicity, and may be misleading

  2. Mutation V111I in HIV-2 reverse transcriptase increases the fitness of the nucleoside analogue-resistant K65R and Q151M viruses

    NARCIS (Netherlands)

    I. Deuzing (Ilona); C. Charpentier (Charlotte); D.J. Wright (David Justin); S. Matheron (Sophie); J. Paton (Jack); D. Frentz (Dineke); D.A.M.C. van de Vijver (David); P.V. Coveney (Peter); D. Descamps (Diane); C.A.B. Boucher (Charles); N. Beerens (Nancy)

    2015-01-01

    textabstractInfection with HIV-2 can ultimately lead to AIDS, although disease progression is much slower than with HIV-1. HIV-2 patients are mostly treated with a combination of nucleoside reverse transcriptase (RT) inhibitors (NRTIs) and protease inhibitors designed for HIV-1. Many studies have

  3. 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…

  4. TFEB ameliorates the impairment of the autophagy-lysosome pathway in neurons induced by doxorubicin

    Science.gov (United States)

    Moruno Manchon, Jose Felix; Uzor, Ndidi-Ese; Kesler, Shelli R.; Wefel, Jeffrey S.; Townley, Debra M.; Nagaraja, Archana Sidalaghatta; Pradeep, Sunila; Mangala, Lingegowda S.; Sood, Anil K.; Tsvetkov, Andrey S.

    2016-01-01

    Doxorubicin, a commonly used chemotherapy agent, induces severe cardio- and neurotoxicity. Molecular mechanisms of cardiotoxicity have been extensively studied, but mechanisms by which doxorubicin exhibits its neurotoxic properties remain unclear. Here, we show that doxorubicin impairs neuronal autophagy, leading to the accumulation of an autophagy substrate p62. Neurons treated with doxorubicin contained autophagosomes, damaged mitochondria, and lipid droplets. The brains from mice treated with pegylated liposomal doxorubicin exhibited autophagosomes, often with mitochondria, lipofuscin, and lipid droplets. Interestingly, lysosomes were less acidic in doxorubicin-treated neurons. Overexpression of the transcription factor EB (TFEB), which controls the autophagy-lysosome axis, increased survival of doxorubicin-treated neurons. 2-Hydroxypropyl-β-cyclodextrin (HPβCD), an activator of TFEB, also promoted neuronal survival, decreased the levels of p62, and lowered the pH in lysosomes. Taken together, substantial changes induced by doxorubicin contribute to neurotoxicity, cognitive disturbances in cancer patients and survivors, and accelerated brain aging. The TFEB pathway might be a new approach for mitigating damage of neuronal autophagy caused by doxorubicin. PMID:27992857

  5. 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.

  6. 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...

  7. A Salmonella nanoparticle mimic overcomes multidrug resistance in tumours.

    Science.gov (United States)

    Mercado-Lubo, Regino; Zhang, Yuanwei; Zhao, Liang; Rossi, Kyle; Wu, Xiang; Zou, Yekui; Castillo, Antonio; Leonard, Jack; Bortell, Rita; Greiner, Dale L; Shultz, Leonard D; Han, Gang; McCormick, Beth A

    2016-07-25

    Salmonella enterica serotype Typhimurium is a food-borne pathogen that also selectively grows in tumours and functionally decreases P-glycoprotein (P-gp), a multidrug resistance transporter. Here we report that the Salmonella type III secretion effector, SipA, is responsible for P-gp modulation through a pathway involving caspase-3. Mimicking the ability of Salmonella to reverse multidrug resistance, we constructed a gold nanoparticle system packaged with a SipA corona, and found this bacterial mimic not only accumulates in tumours but also reduces P-gp at a SipA dose significantly lower than free SipA. Moreover, the Salmonella nanoparticle mimic suppresses tumour growth with a concomitant reduction in P-gp when used with an existing chemotherapeutic drug (that is, doxorubicin). On the basis of our finding that the SipA Salmonella effector is fundamental for functionally decreasing P-gp, we engineered a nanoparticle mimic that both overcomes multidrug resistance in cancer cells and increases tumour sensitivity to conventional chemotherapeutics.

  8. Up-regulation of miR-200 and let-7 by natural agents leads to the reversal of epithelial-mesenchymal transition in gemcitabine-resistant pancreatic cancer cells

    Science.gov (United States)

    Li, Yiwei; VandenBoom, Timothy G.; Kong, Dejuan; Wang, Zhiwei; Ali, Shadan; Philip, Philip A.; Sarkar, Fazlul H.

    2009-01-01

    Pancreatic cancer (PC) is the fourth most common cause of cancer death in the United States and the aggressiveness of PC is in part due to its intrinsic and extrinsic drug resistance characteristics, which is also associated with the acquisition of epithelial-to-mesenchymal transition (EMT). Emerging evidence also suggest that the processes of EMT is regulated by the expression status of many microRNAs (miRNAs), which are believed to function as key regulators of various biological and pathological processes during tumor development and progression. In the present study, we compared the expression of miRNAs between gemcitabine-sensitive and gemcitabine-resistant PC cells, and investigated whether the treatment of cells with “natural agents” [3,3′-diinodolylmethane (DIM) or isoflavone] could affect the expression of miRNAs. We found that the expression of miR-200b, miR-200c, let-7b, let-7c, let-7d, and let-7e was significantly down-regulated in gemcitabine-resistant cells that showed EMT characteristics such as elongated fibroblastoid morphology, lower expression of epithelial marker E-cadherin, and higher expression of mesenchymal markers such as vimentin and ZEB1. Moreover, we found that re-expression of miR-200 by transfection studies or treatment of gemcitabine-resistant cells with either DIM or isoflavone resulted in the down-regulation of ZEB1, slug, and vimentin, which was consistent with morphological reversal of EMT phenotype leading to epithelial morphology. These results provide experimental evidence, for the first time, that DIM and isoflavone could function as miRNA regulators leading to the reversal of EMT phenotype, which is likely to be important for designing novel therapies for PC. PMID:19654291

  9. 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.

  10. 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.

  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. High Potency of Indolyl Aryl Sulfone Nonnucleoside Inhibitors towards Drug-Resistant Human Immunodeficiency Virus Type 1 Reverse Transcriptase Mutants Is Due to Selective Targeting of Different Mechanistic Forms of the Enzyme

    Science.gov (United States)

    Cancio, Reynel; Silvestri, Romano; Ragno, Rino; Artico, Marino; De Martino, Gabriella; La Regina, Giuseppe; Crespan, Emmanuele; Zanoli, Samantha; Hübscher, Ulrich; Spadari, Silvio; Maga, Giovanni

    2005-01-01

    Indolyl aryl sulfone (IAS) nonnucleoside inhibitors have been shown to potently inhibit the growth of wild-type and drug-resistant human immunodeficiency virus type 1 (HIV-1), but their exact mechanism of action has not been elucidated yet. Here, we describe the mechanism of inhibition of HIV-1 reverse transcriptase (RT) by selected IAS derivatives. Our results showed that, depending on the substitutions introduced in the IAS common pharmacophore, these compounds can be made selective for different enzyme-substrate complexes. Moreover, we showed that the molecular basis for this selectivity was a different association rate of the drug to a particular enzymatic form along the reaction pathway. By comparing the activities of the different compounds against wild-type RT and the nonnucleoside reverse transcriptase inhibitor-resistant mutant Lys103Asn, it was possible to hypothesize, on the basis of their mechanism of action, a rationale for the design of drugs which could overcome the steric barrier imposed by the Lys103Asn mutation. PMID:16251294

  13. Assessment of the safety of hydrogenated resistant maltodextrin: reverse mutation assay, acute and 90-day subchronic repeated oral toxicity in rats, and acute no-effect level for diarrhea in humans.

    Science.gov (United States)

    Yoshikawa, Yuko; Kishimoto, Yuka; Tagami, Hiroyuki; Kanahori, Sumiko

    2013-01-01

    A series of safety assessments were performed on hydrogenated resistant maltodextrin prepared by converting the reducing terminal glucose of resistant maltodextrin into sorbitol. The reverse mutation assay did not show mutagenicity. Acute and 90-day subchronic oral toxicity studies in rats showed no death was observed in any groups, including the group receiving the highest single dose of 10 g/kg body weight or the highest dose of 5 g/kg body weight per day for 90 days. Mucous or watery stools were observed in the hydrogenated resistant maltodextrin treatment group on the acute study, which were transient and were associated with the osmotic pressure caused by intake of the high concentrations. Subchronic study showed dose-dependent increases in the weights of cecum alone, cecal contents alone, and cecum with cecal contents as well as hypertrophy of the cecal mucosal epithelium, which are considered to be common physiological responses after intake of indigestible carbohydrates. These results indicated that the no observed adverse effect level (NOAEL) of hydrogenated resistant maltodextrin was 10 g/kg body weight or more on the acute oral toxicity study and 5.0 g/kg body weight/day or more on the 90-day subchronic repeated oral toxicity study in rats. Further study performed in healthy adult humans showed that the acute no-effect level of hydrogenated resistant maltodextrin for diarrhea was 0.8 g/kg body weight for men and more than 1.0 g/kg body weight for women. The results of the current safety assessment studies suggest that hydrogenated resistant maltodextrin is safe for human consumption.

  14. 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

  15. Proteomic profiling reveals that resveratrol inhibits HSP27 expression and sensitizes breast cancer cells to doxorubicin therapy.

    Directory of Open Access Journals (Sweden)

    José Díaz-Chávez

    Full Text Available The use of chemopreventive natural compounds represents a promising strategy in the search for novel therapeutic agents in cancer. Resveratrol (3,4',5-trans-trihydroxystilbilene is a dietary polyphenol found in fruits, vegetables and medicinal plants that exhibits chemopreventive and antitumor effects. In this study, we searched for modulated proteins with preventive or therapeutic potential in MCF-7 breast cancer cells exposed to resveratrol. Using two-dimensional electrophoresis we found significant changes (FC >2.0; p≤0.05 in the expression of 16 proteins in resveratrol-treated MCF-7 cells. Six down-regulated proteins were identified by tandem mass spectrometry (ESI-MS/MS as heat shock protein 27 (HSP27, translationally-controlled tumor protein, peroxiredoxin-6, stress-induced-phosphoprotein-1, pyridoxine-5'-phosphate oxidase-1 and hypoxanthine-guanine phosphoribosyl transferase; whereas one up-regulated protein was identified as triosephosphate isomerase. Particularly, HSP27 overexpression has been associated to apoptosis inhibition and resistance of human cancer cells to therapy. Consistently, we demonstrated that resveratrol induces apoptosis in MCF-7 cells. Apoptosis was associated with a significant increase in mitochondrial permeability transition, cytochrome c release in cytoplasm, and caspases -3 and -9 independent cell death. Then, we evaluated the chemosensitization effect of increasing concentrations of resveratrol in combination with doxorubicin anti-neoplastic agent in vitro. We found that resveratrol effectively sensitize MCF-7 cells to cytotoxic therapy. Next, we evaluated the relevance of HSP27 targeted inhibition in therapy effectiveness. Results evidenced that HSP27 inhibition using RNA interference enhances the cytotoxicity of doxorubicin. In conclusion, our data indicate that resveratrol may improve the therapeutic effects of doxorubicin in part by cell death induction. We propose that potential modulation of HSP27

  16. Proteomic profiling reveals that resveratrol inhibits HSP27 expression and sensitizes breast cancer cells to doxorubicin therapy.

    Science.gov (United States)

    Díaz-Chávez, José; Fonseca-Sánchez, Miguel A; Arechaga-Ocampo, Elena; Flores-Pérez, Ali; Palacios-Rodríguez, Yadira; Domínguez-Gómez, Guadalupe; Marchat, Laurence A; Fuentes-Mera, Lizeth; Mendoza-Hernández, Guillermo; Gariglio, Patricio; López-Camarillo, César

    2013-01-01

    The use of chemopreventive natural compounds represents a promising strategy in the search for novel therapeutic agents in cancer. Resveratrol (3,4',5-trans-trihydroxystilbilene) is a dietary polyphenol found in fruits, vegetables and medicinal plants that exhibits chemopreventive and antitumor effects. In this study, we searched for modulated proteins with preventive or therapeutic potential in MCF-7 breast cancer cells exposed to resveratrol. Using two-dimensional electrophoresis we found significant changes (FC >2.0; p≤0.05) in the expression of 16 proteins in resveratrol-treated MCF-7 cells. Six down-regulated proteins were identified by tandem mass spectrometry (ESI-MS/MS) as heat shock protein 27 (HSP27), translationally-controlled tumor protein, peroxiredoxin-6, stress-induced-phosphoprotein-1, pyridoxine-5'-phosphate oxidase-1 and hypoxanthine-guanine phosphoribosyl transferase; whereas one up-regulated protein was identified as triosephosphate isomerase. Particularly, HSP27 overexpression has been associated to apoptosis inhibition and resistance of human cancer cells to therapy. Consistently, we demonstrated that resveratrol induces apoptosis in MCF-7 cells. Apoptosis was associated with a significant increase in mitochondrial permeability transition, cytochrome c release in cytoplasm, and caspases -3 and -9 independent cell death. Then, we evaluated the chemosensitization effect of increasing concentrations of resveratrol in combination with doxorubicin anti-neoplastic agent in vitro. We found that resveratrol effectively sensitize MCF-7 cells to cytotoxic therapy. Next, we evaluated the relevance of HSP27 targeted inhibition in therapy effectiveness. Results evidenced that HSP27 inhibition using RNA interference enhances the cytotoxicity of doxorubicin. In conclusion, our data indicate that resveratrol may improve the therapeutic effects of doxorubicin in part by cell death induction. We propose that potential modulation of HSP27 levels using natural

  17. 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.

  18. Correction to: Direct effects of doxorubicin on skeletal muscle contribute to fatigue

    NARCIS (Netherlands)

    Norren, van K.; Helvoort, van A.; Agriles, J.M.; Tuijl, van S.; Arts, K.; Gorselink, M.; Laviano, A.; Kegler, D.; Haagsman, H.P.; Beek, van der E.M.

    2009-01-01

    Chemotherapy-induced fatigue is a multidimensional symptom. Oxidative stress has been proposed as a working mechanism for anthracycline-induced cardiotoxicity. In this study, doxorubicin (DOX) was tested on skeletal muscle function. Doxorubicin induced impaired ex vivo skeletal muscle relaxation

  19. Peroxisomes contribute to oxidative stress in neurons during doxorubicin-based chemotherapy.

    Science.gov (United States)

    Moruno-Manchon, Jose F; Uzor, Ndidi-Ese; Kesler, Shelli R; Wefel, Jeffrey S; Townley, Debra M; Nagaraja, Archana Sidalaghatta; Pradeep, Sunila; Mangala, Lingegowda S; Sood, Anil K; Tsvetkov, Andrey S

    2018-01-01

    Doxorubicin, a commonly used anti-neoplastic agent, causes severe neurotoxicity. Doxorubicin promotes thinning of the brain cortex and accelerates brain aging, leading to cognitive impairment. Oxidative stress induced by doxorubicin contributes to cellular damage. In addition to mitochondria, peroxisomes also generate reactive oxygen species (ROS) and promote cell senescence. Here, we investigated if doxorubicin affects peroxisomal homeostasis in neurons. We demonstrate that the number of peroxisomes is increased in doxorubicin-treated neurons and in the brains of mice which underwent doxorubicin-based chemotherapy. Pexophagy, the specific autophagy of peroxisomes, is downregulated in neurons, and peroxisomes produce more ROS. 2-hydroxypropyl-β-cyclodextrin (HPβCD), an activator of the transcription factor TFEB, which regulates expression of genes involved in autophagy and lysosome function, mitigates damage of pexophagy and decreases ROS production induced by doxorubicin. We conclude that peroxisome-associated oxidative stress induced by doxorubicin may contribute to neurotoxicity, cognitive dysfunction, and accelerated brain aging in cancer patients and survivors. Peroxisomes might be a valuable new target for mitigating neuronal damage caused by chemotherapy drugs and for slowing down brain aging in general. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Antitumor Properties of Modified Detonation Nanodiamonds and Sorbed Doxorubicin on the Model of Ehrlich Ascites Carcinoma.

    Science.gov (United States)

    Medvedeva, N N; Zhukov, E L; Inzhevatkin, E V; Bezzabotnov, V E

    2016-01-01

    We studied antitumor properties of modified detonation nanodiamonds loaded with doxorubicin on in vivo model of Ehrlich ascites carcinoma. The type of tumor development and morphological characteristics of the liver, kidneys, and spleen were evaluated in experimental animals. Modified nanodiamonds injected intraperitoneally produced no antitumor effect on Ehrlich carcinoma. However, doxorubicin did not lose antitumor activity after sorption on modified nanodiamonds.

  1. Temporary reversal by topotecan of marked insulin resistance in a patient with myelodysplastic syndrome: case report and possible mechanism for tumor necrosis factor alpha (TNF-alpha)-induced insulin resistance.

    Science.gov (United States)

    Huntington, M O; Krell, K E; Armour , W E; Liljenquist, J E

    2001-06-01

    Tumor necrosis factor-alpha (TNF-alpha) is an important mediator of insulin resistance in obesity and diabetes through its ability to decrease the tyrosine kinase activity of the insulin receptor. We report here a remarkable degree of insulin resistance in a patient with adult respiratory distress syndrome and myelodysplasia.

  2. Role of breast cancer resistance protein in the bioavailability and fetal penetration of topotecan

    NARCIS (Netherlands)

    Jonker, JW; Smit, JW; Brinkhuis, RF; Maliepaard, M; Beijnen, JH; Schellens, JHM; Schinkel, AH

    2000-01-01

    Background and Methods: Breast cancer resistance protein (BCRP/MXR/ABCP) is a multidrug-resistance protein that is a member of the adenosine triphosphate-binding cassette family of drug transporters. BCRP can render tumor cells resistant to the anticancer drugs topotecan, mitoxantrone, doxorubicin,

  3. 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

  4. Long-term analysis of resistance development in HIV-1 positive patients treated with protease and reverse transcriptase inhibitors: Correlation of the genotype and disease progression

    Czech Academy of Sciences Publication Activity Database

    Prejdová, Jana; Weber, Jan; Machala, L.; Reiniš, Milan; Linka, M.; Brůčková, M.; Vandasová, M.; Staňková, M.; Konvalinka, Jan

    2005-01-01

    Roč. 49, č. 1 (2005), 29-36 ISSN 0001-723X R&D Projects: GA MZd(CZ) NI6339 Grant - others:5th Framework(XE) QLK2-CT-2001-02360 Institutional research plan: CEZ:AV0Z4055905 Keywords : HIV * protease inhibitors * resistance development Subject RIV: CE - Biochemistry Impact factor: 0.696, year: 2005

  5. 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.

  6. Reverse transcriptase-real time PCR analysis of heavy metal stress response in a uranium resistant Pseudomonas aeruginosa strain isolated from Jaduguda uranium mine

    International Nuclear Information System (INIS)

    Choudhary, Sangeeta; Sar, Pinaki

    2011-01-01

    A multimetal resistant Pseudomonas strain isolated from a uranium mine waste site of Jaduguda, India, was characterized for its potential application in bioremediation. Nearly complete 16 Sr RNA gene sequence and fatty acid methyl ester analyses confirmed the identity of this bacterium as Pseudomonas aeruginosa. This bacterium exhibited high U-resistance i.e. up to an exposure of 6 h in 100 mg UL -1 solution (pH 4.0) and accumulation (maximum of 275 mg Ug -1 cell dry wt.) properties. Microcosm studies further proved the ability of the strain to remove soluble uranium (99%) from U-mine effluent and sequester it as U oxide and phosphate minerals while maintaining its viability. Considering the survival of this strain in U-mine site co-contaminated with other heavy metals, genetic basis of metal resistance was investigated. The bacterium was resistant to 3, 2 or 6 mM of Cu, Cd, or Zn, respectively. Polymerase chain reaction based detection followed by sequence identity and phylogenetic analysis revealed presence of specific metal resistance genes copA (copper resistance determinant) and czcA (RND type heavy metal efflux) in this isolate. Real-time PCR expression studies of these genes indicated significantly increased expression of both the genes in response to Cu, Cd, or Zn. Maximum up regulation of copA and czcA genes was observed following exposure (30 mm) to 25 μm of Cu or 10 μm Cd respectively. High levels of mRNA transcripts of copA and czcA genes in response to specific metals suggest that these resistance systems have important role in conferring metal resistance to the bacterium. Response of sodA an antioxidant Mn-cofactored superoxide dismutase gene to metal stress revealed that induction of this stress gene was not evident at lower concentration(s) of metals, the concentration(s) that cause maximum up- regulation of metal resistance genes. Higher test metal concentration or extended period of exposure, however, resulted in expression of sodA gene. The

  7. Mechanisms for Breast Cancer Cell Resistance to Doxorubicin and Solutions to Resistance and Side Effects

    Science.gov (United States)

    2001-10-01

    anthracyclines derive at least some of their toxicity to tumor cells from covalent bonding to DNA, to determine why anthracycline-formaldehyde conjugates overcome... conjugates . HPLC analysis of cell content and culture broth using synthetic standards of potential conjugates showed unequivocally that no GSH- conjugates ...abundant for oxidation of linoleic acid (12). We have reinvestigated the Tamura experiment because it was performed in Tris buffer. Earlier we reported that

  8. 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.

  9. Stabilization of mitochondrial membrane potential prevents doxorubicin-induced cardiotoxicity in isolated rat heart

    International Nuclear Information System (INIS)

    Montaigne, David; Marechal, Xavier; Baccouch, Riadh; Modine, Thomas; Preau, Sebastien; Zannis, Konstantinos; Marchetti, Philippe; Lancel, Steve; Neviere, Remi

    2010-01-01

    The present study was undertaken to examine the effects of doxorubicin on left ventricular function and cellular energy state in intact isolated hearts, and, to test whether inhibition of mitochondrial membrane potential dissipation would prevent doxorubicin-induced mitochondrial and myocardial dysfunction. Myocardial contractile performance and mitochondrial respiration were evaluated by left ventricular tension and its first derivatives and cardiac fiber respirometry, respectively. NADH levels, mitochondrial membrane potential and glucose uptake were monitored non-invasively via epicardial imaging of the left ventricular wall of Langendorff-perfused rat hearts. Heart performance was reduced in a time-dependent manner in isolated rat hearts perfused with Krebs-Henseleit solution containing 1 μM doxorubicin. Compared with controls, doxorubicin induced acute myocardial dysfunction (dF/dt max of 105 ± 8 mN/s in control hearts vs. 49 ± 7 mN/s in doxorubicin-treated hearts; *p < 0.05). In cardiac fibers prepared from perfused hearts, doxorubicin induced depression of mitochondrial respiration (respiratory control ratio of 4.0 ± 0.2 in control hearts vs. 2.2 ± 0.2 in doxorubicin-treated hearts; *p < 0.05) and cytochrome c oxidase kinetic activity (24 ± 1 μM cytochrome c/min/mg in control hearts vs. 14 ± 3 μM cytochrome c/min/mg in doxorubicin-treated hearts; *p < 0.05). Acute cardiotoxicity induced by doxorubicin was accompanied by NADH redox state, mitochondrial membrane potential, and glucose uptake reduction. Inhibition of mitochondrial permeability transition pore opening by cyclosporine A largely prevented mitochondrial membrane potential dissipation, cardiac energy state and dysfunction. These results suggest that in intact hearts an impairment of mitochondrial metabolism is involved in the development of doxorubicin cardiotoxicity.

  10. Visible-light system for detecting doxorubicin contamination on skin and surfaces.

    Science.gov (United States)

    Van Raalte, J; Rice, C; Moss, C E

    1990-05-01

    A portable system that uses fluorescence stimulated by visible light to identify doxorubicin contamination on skin and surfaces was studied. When activated by violet-blue light in the 465-nm range, doxorubicin fluoresces, emitting orange-red light in the 580-nm range. The light source to stimulate fluorescence was a slide projector with a filter to selectively pass short-wave (blue) visible light. Fluorescence was both observed visually with viewing spectacles and photographed. Solutions of doxorubicin in sterile 0.9% sodium chloride injection were prepared in nine standard concentrations ranging from 2 to 0.001 mg/mL. Droplets of each admixture were placed on stainless steel, laboratory coat cloth, pieces of latex examination glove, bench-top absorbent padding, and other materials on which antineoplastics might spill or leak. These materials then were stored for up to eight weeks and photographed weekly. The relative ability of water, household bleach, hydrogen peroxide solution, and soap solution to deactivate doxorubicin was also measured. Finally, this system was used to inspect the antineoplastic-drug preparation and administration areas of three outpatient cancer clinics for doxorubicin contamination. Doxorubicin fluorescence was easily detectable with viewing spectacles when a slide projector was used as the light source. The photographic method was sensitive for doxorubicin concentrations from 2.0 to 0.001 mg/mL. Immersion of study materials in bleach for one minute eliminated detectable fluorescence. Doxorubicin contamination is detectable for at least eight weeks in the ambient environment. Probable doxorubicin contamination was detected in two of the three clinics surveyed. A safe, portable system that uses fluorescence stimulated by visible light is a sensitive method for detecting doxorubicin on skin and surfaces.

  11. 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 and its periodic review by analysis of the information that is made available from time to time. This will enable us to utilize our limited resources in most prudent way.

  12. Interaction of the EGFR inhibitors gefitinib, vandetanib, pelitinib and neratinib with the ABCG2 multidrug transporter: implications for the emergence and reversal of cancer drug resistance.

    Science.gov (United States)

    Hegedüs, Csilla; Truta-Feles, Krisztina; Antalffy, Géza; Várady, György; Német, Katalin; Ozvegy-Laczka, Csilla; Kéri, György; Orfi, László; Szakács, Gergely; Settleman, Jeffrey; Váradi, András; Sarkadi, Balázs

    2012-08-01

    Human ABCG2 is a plasma membrane glycoprotein that provides physiological protection against xenobiotics. ABCG2 also significantly influences biodistribution of drugs through pharmacological tissue barriers and confers multidrug resistance to cancer cells. Moreover, ABCG2 is the molecular determinant of the side population that is characteristically enriched in normal and cancer stem cells. Numerous tumors depend on unregulated EGFR signaling, thus inhibition of this receptor by small molecular weight inhibitors such as gefitinib, and the novel second generation agents vandetanib, pelitinib and neratinib, is a promising therapeutic option. In the present study, we provide detailed biochemical characterization regarding the interaction of these EGFR inhibitors with ABCG2. We show that ABCG2 confers resistance to gefitinib and pelitinib, whereas the intracellular action of vandetanib and neratinib is unaltered by the presence of the transporter. At higher concentrations, however, all these EGFR inhibitors inhibit ABCG2 function, thereby promoting accumulation of ABCG2 substrate drugs. We also report enhanced expression of ABCG2 in gefitinib-resistant non-small cell lung cancer cells, suggesting potential clinical relevance of ABCG2 in acquired drug resistance. Since ABCG2 has important impact on both the pharmacological properties and anti-cancer efficiencies of drugs, our results regarding the novel EGFR inhibitors should provide useful information about their therapeutic applicability against ABCG2-expressing cancer cells depending on EGFR signaling. In addition, the finding that these EGFR inhibitors efficiently block ABCG2 function may help to design novel drug-combination therapeutic strategies. Copyright © 2012 Elsevier Inc. All rights reserved.

  13. Differential cardiotoxicity in response to chronic doxorubicin treatment in male spontaneous hypertension-heart failure (SHHF), spontaneously hypertensive (SHR), and Wistar Kyoto (WKY) rats

    Energy Technology Data Exchange (ETDEWEB)

    Sharkey, Leslie C., E-mail: shark009@umn.edu [Veterinary Clinical Sciences Department, University of Minnesota, 1352 Boyd Ave, St. Paul, MN 55108 (United States); Radin, M. Judith, E-mail: radin.1@osu.edu [Department of Veterinary Biosciences, The Ohio State University, 1925 Coffey Road, Columbus, OH 43210 (United States); Heller, Lois, E-mail: lheller@d.umn.edu [Department of Biomedical Sciences, University of Minnesota Medical School—Duluth, 1035 University Drive, Duluth, MN 55812-3031 (United States); Rogers, Lynette K., E-mail: Lynette.Rogers@nationwidechildrens.org [Center for Perinatal Research, The Research Institute at Nationwide Children' s Hospital, 700 Childrens Drive, Columbus, OH 43205 (United States); Tobias, Anthony [Veterinary Clinical Sciences Department, University of Minnesota, 1352 Boyd Ave, St. Paul, MN 55108 (United States); Matise, Ilze, E-mail: imatise.vh@gmail.com [Veterinary Population Medicine Department, University of Minnesota, 1365 Gortner Ave, St Paul, MN (United States); Wang, Qi, E-mail: wangx890@umn.edu [Clinical and Translational Science Institute (CTSI), University of Minnesota, 717 Delaware St SE, Minneapolis, MN (United States); Apple, Fred S., E-mail: apple004@umn.edu [Department of Laboratory Medicine and Pathology, Hennepin County Medical Center and University of Minnesota, 701 Park Ave S, Minneapolis, MN USA (United States); McCune, Sylvia A., E-mail: sylvia.mccune@skybeam.com [Department of Integrative Physiology, University of Colorado at Boulder, 354 UCB, Clare Small 114, Boulder, CO 80309 (United States)

    2013-11-15

    Life threatening complications from chemotherapy occur frequently in cancer survivors, however little is known about genetic risk factors. We treated male normotensive rats (WKY) and strains with hypertension (SHR) and hypertension with cardiomyopathy (SHHF) with 8 weekly doses of doxorubicin (DOX) followed by 12 weeks of observation to test the hypothesis that genetic cardiovascular disease would worsen delayed cardiotoxicity. Compared with WKY, SHR demonstrated weight loss, decreased systolic blood pressure, increased kidney weights, greater cardiac and renal histopathologic lesions and greater mortality. SHHF showed growth restriction, increased kidney weights and renal histopathology but no effect on systolic blood pressure or mortality. SHHF had less severe cardiac lesions than SHR. We evaluated cardiac soluble epoxide hydrolase (sEH) content and arachidonic acid metabolites after acute DOX exposure as potential mediators of genetic risk. Before DOX, SHHF and SHR had significantly greater cardiac sEH and decreased epoxyeicosatrienoic acid (EET) (4 of 4 isomers in SHHF and 2 of 4 isomers in SHR) than WKY. After DOX, sEH was unchanged in all strains, but SHHF and SHR rats increased EETs to a level similar to WKY. Leukotriene D4 increased after treatment in SHR. Genetic predisposition to heart failure superimposed on genetic hypertension failed to generate greater toxicity compared with hypertension alone. The relative resistance of DOX-treated SHHF males to the cardiotoxic effects of DOX in the delayed phase despite progression of genetic disease was unexpected and a key finding. Strain differences in arachidonic acid metabolism may contribute to variation in response to DOX toxicity. - Highlights: • Late doxorubicin toxicity evaluated in normal, hypertensive, and cardiomyopathic rats. • Hypertension enhances the delayed toxicity of doxorubicin. • Genetic predisposition to cardiomyopathy did not further enhance toxicity. • Epoxyeicosatrienoic acids

  14. Specific down-regulation of XIAP with RNA interference enhances the sensitivity of canine tumor cell-lines to TRAIL and doxorubicin

    Directory of Open Access Journals (Sweden)

    Rothuizen Jan

    2006-09-01

    Full Text Available Abstract Background Apoptosis resistance occurs in various tumors. The anti-apoptotic XIAP protein is responsible for inhibiting apoptosis by reducing caspase-3 activation. Our aim is to evaluate whether RNA inhibition against XIAP increases the sensitivity of canine cell-lines for chemotherapeutics such as TRAIL and doxorubicin. We used small interfering RNA's (siRNA directed against XIAP in three cell-lines derived from bile-duct epithelia (BDE, mammary carcinoma (P114, and osteosarcoma (D17. These cell-lines represent frequently occurring canine cancers and are highly comparable to their human counterparts. XIAP down-regulation was measured by means of quantitative PCR (Q-PCR and Western blotting. The XIAP depleted cells were treated with a serial dilution of TRAIL or doxorubicin and compared to mock- and nonsense-treated controls. Viability was measured with a MTT assay. Results All XIAP siRNA treated cell-lines showed a mRNA down-regulation over 80 percent. Western blot analysis confirmed mRNA measurements. No compensatory effect of IAP family members was seen in XIAP depleted cells. The sensitivity of XIAP depleted cells for TRAIL was highest in BDE cells with an increase in the ED50 of 14-fold, compared to mock- and nonsense-treated controls. The sensitivity of P114 and D17 cell-lines increased six- and five-fold, respectively. Doxorubicin treatment in XIAP depleted cells increased sensitivity in BDE cells more than eight-fold, whereas P114 and D17 cell-lines showed an increase in sensitivity of three- and five-fold, respectively. Conclusion XIAP directed siRNA's have a strong sensitizing effect on TRAIL-reduced cell-viability and a smaller but significant effect with the DNA damaging drug doxorubicin. The increase in efficacy of chemotherapeutics with XIAP depletion provides the rationale for the use of XIAP siRNA's in insensitive canine tumors.

  15. Binding and internalization of NGR-peptide-targeted liposomal doxorubicin (TVT-DOX) in CD13-expressing cells and its antitumor effects.

    Science.gov (United States)

    Garde, Seema V; Forté, André J; Ge, Michael; Lepekhin, Eugene A; Panchal, Chandra J; Rabbani, Shafaat A; Wu, Jinzi J

    2007-11-01

    In an effort to develop new agents and molecular targets for the treatment of cancer, aspargine-glycine-arginine (NGR)-targeted liposomal doxorubicin (TVT-DOX) is being studied. The NGR peptide on the surface of liposomal doxorubicin (DOX) targets an aminopeptidase N (CD13) isoform, specific to the tumor neovasculature, making it a promising strategy. To further understand the molecular mechanisms of action, we investigated cell binding, kinetics of internalization as well as cytotoxicity of TVT-DOX in vitro. We demonstrate the specific binding of TVT-DOX to CD13-expressing endothelial [human umbilical vein endothelial cells (HUVEC) and Kaposi sarcoma-derived endothelial cells (SLK)] and tumor (fibrosarcoma, HT-1080) cells in vitro. Following binding, the drug was shown to internalize through the endosomal pathway, eventually leading to the localization of doxorubicin in cell nuclei. TVT-DOX showed selective toxicity toward CD13-expressing HUVEC, sparing the CD13-negative colon-cancer cells, HT-29. Additionally, the nontargeted counterpart of TVT-DOX, Caelyx, was less cytotoxic to the CD13-positive HUVECs demonstrating the advantages of NGR targeting in vitro. The antitumor activity of TVT-DOX was tested in nude mice bearing human prostate-cancer xenografts (PC3). A significant growth inhibition (up to 60%) of PC3 tumors in vivo was observed. Reduction of tumor vasculature following treatment with TVT-DOX was also apparent. We further compared the efficacies of TVT-DOX and free doxorubicin in the DOX-resistant colon-cancer model, HCT-116, and observed the more pronounced antitumor effects of the TVT-DOX formulation over free DOX. The potential utility of TVT-DOX in a variety of vascularized solid tumors is promising.

  16. Zoledronic acid enhances antitumor efficacy of liposomal doxorubicin.

    Science.gov (United States)

    Hattori, Yoshiyuki; Shibuya, Kazuhiko; Kojima, Kaori; Miatmoko, Andang; Kawano, Kumi; Ozaki, Kei-Ichi; Yonemochi, Etsuo

    2015-07-01

    Previously, we found that the injection of zoledronic acid (ZOL) into mice bearing tumor induced changes of the vascular structure in the tumor. In this study, we examined whether ZOL treatment could decrease interstitial fluid pressure (IFP) via change of tumor vasculature, and enhance the antitumor efficacy of liposomal doxorubicin (Doxil®). When ZOL solution was injected at 40 µg/mouse per day for three consecutive days into mice bearing murine Lewis lung carcinoma LLC tumor, depletion of macrophages in tumor tissue and decreased density of tumor vasculature were observed. Furthermore, ZOL treatments induced inflammatory cytokines such as interleukin (IL)-10 and -12, granulocyte-macrophage colony-stimulating factor (GM-CSF) and tumor necrosis factor (TNF)-α in serum of LLC tumor-bearing mice, but not in normal mice, indicating that ZOL treatments might induce an inflammatory response in tumor tissue. Furthermore, ZOL treatments increased antitumor activity by Doxil in mice bearing a subcutaneous LLC tumor, although they did not significantly increase the tumor accumulation of doxorubicin (DXR). These results suggest that ZOL treatments might increase the therapeutic efficacy of Doxil via improvement of DXR distribution in a tumor by changing the tumor vasculature. ZOL treatment can be an alternative approach to increase the antitumor effect of liposomal drugs.

  17. 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...

  18. In vivo multimodality imaging of miRNA-16 iron nanoparticle reversing drug resistance to chemotherapy in a mouse gastric cancer model

    Science.gov (United States)

    Sun, Zhongchan; Song, Xinxing; Li, Xiujuan; Su, Tao; Qi, Shun; Qiao, Ruirui; Wang, Fu; Huan, Yi; Yang, Weidong; Wang, Jing; Nie, Yongzhan; Wu, Kaichun; Gao, Mingyuan; Cao, Feng

    2014-11-01

    miRNA-16 (miR16) plays an important role in modulating the drug resistance of SGC7901 cell lines to adriamycin (ADR). A variety of viral carriers have been designed for miRNA delivery. However, the safety concerns are currently perceived as hampering the clinical application of viral vector-based therapy. Herein a type of magnetic nanoparticles (MNPs) was designed and synthesized using poly(ethylene glycol) (PEG)-coated Fe3O4 nanoparticles as a miRNA delivery system for the purpose of reducing drug resistance of gastric cancer cells by enforcing miR16 expression in SGC7901/ADR cells. The MNPs with good biocompatibility were synthesized by thermal decomposition, and then conjugated with miRNA via electrostatic interaction producing miR16/MNPs. After co-culture with miR16/MNPs, ADR-induced apoptosis of SGC7901/ADR was examined by MTT and TUNEL. miR16/MNPs treatment significantly increased cell apoptosis in vitro. SGC7901/ADRfluc tumor-bearing nude mice under ADR therapy were treated with miR16/MNPs by tail vein injection for in vivo study. After intraperitoneal injection of ADR, tumor volume measurement and fluorescence imaging were performed to for the death of SGC7901/ADR cells in vivo. Results showed that miR16/MNPs were able to significantly suppress SGC7901/ADR tumor growth, probably through increasing SGC7901/ADR cells' sensitivity to ADR. Our results suggest the efficient delivery of miR16 by MNPs as a novel therapeutic strategy for drug resistant tumor treatment.miRNA-16 (miR16) plays an important role in modulating the drug resistance of SGC7901 cell lines to adriamycin (ADR). A variety of viral carriers have been designed for miRNA delivery. However, the safety concerns are currently perceived as hampering the clinical application of viral vector-based therapy. Herein a type of magnetic nanoparticles (MNPs) was designed and synthesized using poly(ethylene glycol) (PEG)-coated Fe3O4 nanoparticles as a miRNA delivery system for the purpose of reducing drug

  19. Low eficiency of n-3 polyunsaturated fatty acids in the reversal of insulin resistance induced by a high-fat in mice

    Czech Academy of Sciences Publication Activity Database

    Jílková, Zuzana; Rossmeisl, Martin; Flachs, Pavel; Kopecký, Jan

    2006-01-01

    Roč. 49, Suppl. 1 (2006), s. 345-346 ISSN 0012-186X. [Annual Meeting of the European Association for the Study of Diabetes /42./. 14.09.2006-17.09.2006, Copenhagen-Malmoe] R&D Projects: GA MŠk(CZ) 1M0520; GA ČR(CZ) GA303/05/2580 Institutional research plan: CEZ:AV0Z50110509 Keywords : insulin resistance * n-3 PUFA * high fat diet Subject RIV: FB - Endocrinology, Diabetology, Metabolism, Nutrition

  20. Increased Dietary Leucine Reduces Doxorubicin-Associated Cardiac Dysfunction in Rats

    Directory of Open Access Journals (Sweden)

    Thiago M. Fidale

    2018-01-01

    Full Text Available Cardiotoxicity is one of the most significant adverse effects of the oncologic treatment with doxorubicin, which is responsible for a substantial morbid and mortality. The occurrence of heart failure with ventricular dysfunction may lead to severe cardiomyopathy and ultimately to death. Studies have focused on the effects of leucine supplementation as a strategy to minimize or revert the clinical condition of induced proteolysis by several clinical onsets. However, the impact of leucine supplementation in heart failure induced by doxorubicin is unknown. Therefore, the objective of this work is to evaluate the effects of leucine supplementation on the cardiotoxicity in the heart of rats treated with doxorubicin. Rats treated with a 7.5 mg/kg cumulative dose of doxorubicin for 14 days presented a dilatation of the left ventricle (LV, and a reduction of the ejection fraction (FE. The 5% supplementation of leucine in the rats' food prevented the malfunctioning of the LV when administered with doxorubicin. Some alterations in the extracellular matrix remodeling were confirmed by the increase of collagen fibers in the doxorubicin group, which did not increase when the treatment was associated with leucine supplementation. Leucine attenuates heart failure in this experimental model with doxorubicin. Such protection is followed by the maintenance of interstitial collagen fibers.

  1. A Typology of Reverse Innovation

    DEFF Research Database (Denmark)

    von Zedtwitz, Max; Corsi, Simone; Søberg, Peder Veng

    2015-01-01

    secondary market introduction, this study expands the espoused definition of reverse innovation beyond its market-introduction focus with reversals in the flow of innovation in the ideation and product development phases. Recognizing that each phase can take place in different geographical locations...... taking place in an emerging country. This analytical framework allows recasting of current research at the intersection between innovation and international business. Of the 10 reverse innovation flows, six are new and have not been covered in the literature to date. The study addresses questions......’s portfolio of global innovation competence and capability. The implications for management are concerned with internal and external resistance to reverse innovation. Most significantly, while greater recognition and power of innovation in formerly subordinate organizational units is inconvenient to some...

  2. Reversal of multidrug resistance with KR-30035: evaluated with biodistribution of Tc-99m MIBI in nude mice bearing human tumor xenografts

    International Nuclear Information System (INIS)

    Kim, Jung Kyun; Lee, Jae Tae; Lee, Byung Ho

    2001-01-01

    KR-30035 (KR), a new MDR reversing agent, has been found to produce a similar degree of increased Tc-99m MIBI uptake in cultured tumor cells over-expressing mdr1 mRNA compared to verapamil (VP), with less cardiovascular effects. We assessed the MDR-reversing ability of KR in vivo, and effects of various doses of KR on MIBI uptake in nude mice bearing P-glycoprotein (P-gp) positive (+) and P-gp negative (-) human tumor xenografts. P-gp (+) HCT15/CLO2 colorectal and P-gp (-) A549 non-small cell cancer cells were inoculated in each flank of 120 nude mice (20 mice x 6 groups). Group 1 (Gr1) mice received 10mg/kg Kr i.p. 3 times (x3); Gr2, 10mg/kg VP i.p. x3; Gr3, 10mg/kg KR i.p. x2 + 25mg/kg KR i.p. x1; Gr4, 10mg/kg KR i.p. x 2 + 50mg/kg i.p. x1; Gr5, 10mg/kg Kr i.p. x2 + 25mg/kg KR i.v. x1, GrC, controls. The mice were then injected with Tc-99m MIBI and sacrificed after 10 min, 30 min, 90 min and 240 min. Tumor uptake of MIBI (TU) in each group was compared. Tu in P-gp (+) and (-)tumors were both higher in Gr1 than Gr2. Washout rate between the 10 min and 4 hours was lower in Gr5 of P-gp (+) cell (0.93) than the control. Percentage increases in Tu were higher in P-gp (+) than P-gp (-) tumors with all KR doses. Pgp (+) TU were highest at 10 min (173% of GrC) and persisted up to 240 min (144%) in Gr3. Larger doses of KR resulted in a lesser degree of increase in P-gp (+) TU at 10 min (130% in Gr4 and 117% in Gr5) and 30 min (178%, 129%), but TU increased by time up to 240 min (177%, 196%). Heart and lung uptakes were markedly increased in Gr4 and Gr5 at 10 and 3C min, likely due to cardiovascular effects. No mice died. These data further suggest that KR that has significantly lower cardiovascular toxicity than verapamil can be used as an active inhibitor of MDR. Even a relatively low dose of KR significantly increased Tc-99m MIBI uptake in P-gp (+) tumors in vivo

  3. Dietary phenolic acids reverse insulin resistance, hyperglycaemia, dyslipidaemia, inflammation and oxidative stress in high-fructose diet-induced metabolic syndrome rats.

    Science.gov (United States)

    Ibitoye, Oluwayemisi B; Ajiboye, Taofeek O

    2017-12-20

    This study investigated the influence of caffeic, ferulic, gallic and protocatechuic acids on high-fructose diet-induced metabolic syndrome in rats. Oral administration of the phenolic acids significantly reversed high-fructose diet-mediated increase in body mass index and blood glucose. Furthermore, phenolic acids restored high-fructose diet-mediated alterations in metabolic hormones (insulin, leptin and adiponectin). Similarly, elevated tumour necrosis factor-α, interleukin-6 and -8 were significantly lowered. Administration of phenolic acids restored High-fructose diet-mediated increase in the levels of lipid parameters and indices of atherosclerosis, cardiac and cardiovascular diseases. High-fructose diet-mediated decrease in activities of antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and glucose 6-phosphate dehydrogenase) and increase in oxidative stress biomarkers (reduced glutathione, lipid peroxidation products, protein oxidation and fragmented DNA) were significantly restored by the phenolic acids. The result of this study shows protective influence of caffeic acid, ferulic acid, gallic acid and protocatechuic acid in high-fructose diet-induced metabolic syndrome.

  4. Salinomycin overcomes ABC transporter-mediated multidrug and apoptosis resistance in human leukemia stem cell-like KG-1a cells

    International Nuclear Information System (INIS)

    Fuchs, Dominik; Daniel, Volker; Sadeghi, Mahmoud; Opelz, Gerhard; Naujokat, Cord

    2010-01-01

    Leukemia stem cells are known to exhibit multidrug resistance by expression of ATP-binding cassette (ABC) transporters which constitute transmembrane proteins capable of exporting a wide variety of chemotherapeutic drugs from the cytosol. We show here that human promyeloblastic leukemia KG-1a cells exposed to the histone deacetylase inhibitor phenylbutyrate resemble many characteristics of leukemia stem cells, including expression of functional ABC transporters such as P-glycoprotein, BCRP and MRP8. Consequently, KG-1a cells display resistance to the induction of apoptosis by various chemotherapeutic drugs. Resistance to apoptosis induction by chemotherapeutic drugs can be reversed by cyclosporine A, which effectively inhibits the activity of P-glycoprotein and BCRP, thus demonstrating ABC transporter-mediated drug resistance in KG-1a cells. However, KG-1a are highly sensitive to apoptosis induction by salinomycin, a polyether ionophore antibiotic that has recently been shown to kill human breast cancer stem cell-like cells and to induce apoptosis in human cancer cells displaying multiple mechanisms of drug and apoptosis resistance. Whereas KG-1a cells can be adapted to proliferate in the presence of apoptosis-inducing concentrations of bortezomib and doxorubicin, salinomycin does not permit long-term adaptation of the cells to apoptosis-inducing concentrations. Thus, salinomycin should be regarded as a novel and effective agent for the elimination of leukemia stem cells and other tumor cells exhibiting ABC transporter-mediated multidrug resistance.

  5. Src kinases in chondrosarcoma chemoresistance and migration: dasatinib sensitises to doxorubicin in TP53 mutant cells

    Science.gov (United States)

    van Oosterwijk, J G; van Ruler, M A J H; Briaire-de Bruijn, I H; Herpers, B; Gelderblom, H; van de Water, B; Bovée, J V M G

    2013-01-01

    Background: Chondrosarcomas are malignant cartilage-forming tumours of bone. Because of their resistance to conventional chemotherapy and radiotherapy, currently no treatment strategies exist for unresectable and metastatic chondrosarcoma. Previously, PI3K/AKT/GSK3β and Src kinase pathways were shown to be activated in chondrosarcoma cell lines. Our aim was to investigate the role of these kinases in chemoresistance and migration in chondrosarcoma in relation to TP53 mutation status. Methods: We used five conventional and three dedifferentiated chondrosarcoma cell lines and investigated the effect of PI3K/AKT/GSK3β pathway inhibition (enzastaurin) and Src pathway inhibition (dasatinib) in chemoresistance using WST assay and live cell imaging with AnnexinV staining. Immunohistochemistry on tissue microarrays (TMAs) containing 157 cartilaginous tumours was performed for Src family members. Migration assays were performed with the RTCA xCelligence System. Results: Src inhibition was found to overcome chemoresistance, to induce apoptosis and to inhibit migration. Cell lines with TP53 mutations responded better to combination therapy than wild-type cell lines (P=0.002). Tissue microarray immunohistochemistry confirmed active Src (pSrc) signalling, with Fyn being most abundantly expressed (76.1%). Conclusion: These results strongly indicate Src family kinases, in particular Fyn, as a potential target for the treatment of inoperable and metastatic chondrosarcomas, and to sensitise for doxorubicin especially in the presence of TP53 mutations. PMID:23922104

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

    Science.gov (United States)

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

    2016-05-01

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

  7. Specificity of tumor necrosis factor toxicity for human mammary carcinomas relative to normal mammary epithelium and correlation with response to doxorubicin

    International Nuclear Information System (INIS)

    Dollbaum, C.; Creasey, A.A.; Dairkee, S.H.; Hiller, A.J.; Rudolph, A.R.; Lin, L.; Vitt, C.; Smith, H.S.

    1988-01-01

    By using a unique short-term culture system capable of growing both normal and malignant breast epithelial tissue, human recombinant tumor necrosis factor (TNF) showed preferential cytotoxicity to malignant cells as compared to the corresponding nonmalignant cells. Most of the malignant specimens were sensitive to TNF with 13 of 18 specimens showing 90% inhibition of clonal growth (ID 90 ). In contrast, all 13 nonmalignant specimens tested clustered at the resistant end of the TNF response spectrum. This differential sensitivity to TNF was seen in three cases in which malignant and nonmalignant breast epithelial tissues from the same patient were studied. To investigate the mechanism of resistance to TNF by normal cells, the presence of receptors for TNF was determined. Five of six cultures showed specific binding of 125 I-labeled TNF and there was no relationship between the degree of resistance and the degree of specific binding. Simultaneous comparison of tumor responsiveness to doxorubicin and TNF revealed a positive correlation in ID 90 values; these results may have important implications for the clinical use of TNF in cancer patients heavily pretreated with doxorubicin

  8. Loading and release of doxorubicin with magnetic nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Xia; Wang, Xiang; Lee, Sang Bok [Dept. of Chemistry and Biochemistry, University of Maryland, College Park (United States); English, Douglas [Dept. of Chemistry, Wichita State University, Wichita (United States)

    2015-03-15

    In this work, we study magnetic nanotubes (MNTs) as drug carriers to control the loading and release of doxorubicin (Dox). The inner surfaces of MNTs where Dox molecules are stored are modified with C18-silane and pyridine–silane. By tuning the interaction between the drug molecules and inner surfaces of MNTs via pH, Dox can be effectively encapsulated at pH 7.2 and released at pH 4.5. The successful loading of Dox is confirmed with confocal microscopy studies. The release profiles of Dox from modified MNTs are detected by spectrofluorophotometry, with bare MNTs as control. With proper modifications, MNTs can be used for pH-dependent, controlled release of drug molecules.

  9. Combined doxorubicin and radiation therapy in malignant pleural mesothelioma

    International Nuclear Information System (INIS)

    Sinoff, C.; Falkson, G.; Sandison, A.G.; De Muelenaere, G.

    1982-01-01

    Ten patients with histologically confirmed inoperable malignant mesothelioma of the pleura were treated with doxorubicin and fractionated radiotherapy courses. Three patients derived significant clinical benefit from this treatment, although only one of the three had measureable tumor shrinkage that could be defined as partial response. Two of the ten patients showed only progressive disease, while the remaining five showed disease stabilization for 30--100 weeks. The treatment was subjectively well-tolerated and hematopoietic toxicity was acceptable. Radiation pneumonitis did not occur. Two of the four patients who lived greater than or equal to 94 weeks developed fibrosis of the irradiated hemithorax. The median survival time for all patients was 46 weeks. Although the combined treatment could be given with acceptable toxic effects and although four patients benefited from it, the best objective assessment, namely, survival time, did not appear to be adequately influenced to justify an extension of this series

  10. Mangifera indica L. leaf extract alleviates doxorubicin induced cardiac stress

    Science.gov (United States)

    Bhatt, Laxit; Joshi, Viraj

    2017-01-01

    Aim: The study was undertaken to evaluate the cardioprotective effect of the alcoholic leaf extract of Mangifera indica L. against cardiac stress caused by doxorubicin (DOX). Materials and Methods: Rats were treated with 100 mg/kg of M. indica leaf extract (MILE) in alone and interactive groups for 21 days. Apart from the normal and MILE control groups, all the groups were subjected to DOX (15 mg/kg, i.p.) toxicity for 21 days and effects of different treatments were analyzed by changes in serum biomarkers, tissue antioxidant levels, electrocardiographic parameters, lipid profile, and histopathological evaluation. Results: The MILE treated group showed decrease in serum biomarker enzyme levels and increase in tissue antioxidants levels. Compared to DOX control group, MILE treated animals showed improvement in lipid profile, electrocardiographic parameters, histological score, and mortality. Conclusion: These findings clearly suggest the protective role of alcoholic leaf extract of M. indica against oxidative stress induced by DOX. PMID:28894627

  11. Myostatin as a Marker for Doxorubicin Induced Cardiac Damage.

    Science.gov (United States)

    Kesik, Vural; Honca, Tevfik; Gulgun, Mustafa; Uysal, Bulent; Kurt, Yasemin Gulcan; Cayci, Tuncer; Babacan, Oguzhan; Gocgeldi, Ercan; Korkmazer, Nadir

    2016-01-01

    Doxorubicin (DXR) is an effective chemotherapeutic agent but causes severe cardiac failure over known doses. Thus, early detection and prevention of cardiac damage is important. Various markers have been tested for early detection of cardiac damage. Myostatin is a protein produced in skeletal muscle cells inhibits muscle differentiation and growth during myogenesis. We evaluated the role of myostatin as a marker for showing DXR induced cardiac damage and compared with well known cardiac markers like NT-proBNP, hs-TnT and CK in a rat model of chronic DXR cardiotoxicity. Myostatin, NT-proBNP, and hs-TnT but not CK rose significantly during DXR treatment. Myostatin can be used as an early marker of DXR induced cardiotoxicity. © 2016 by the Association of Clinical Scientists, Inc.

  12. Amphipathic dextran-doxorubicin prodrug micelles for solid tumor therapy.

    Science.gov (United States)

    Jin, Rong; Guo, Xuelian; Dong, Lingli; Xie, Enyuan; Cao, Aoneng

    2017-10-01

    A group of micelles self-assembled from deoxycholic acid-doxorubicin-conjugated dextran (denoted as Dex-DCA-DOX) prodrugs were designed and prepared for pH-triggered drug release and cancer chemotherapy. These prodrugs could be successfully produced by chemically coupling hydrophobic deoxycholic acid (DCA) to dextran hydrazine (denoted as Dex-NHNH 2 ) and hydrazone linker formation between doxorubicin (DOX) and Dex-NHNH 2 . These Dex-DCA-DOX prodrugs self-assembled to form micelles under physiological conditions with varied particle sizes depending on molecular weight of dextran, degree of substitution (DS) of DCA and DOX. After optimization, Dex10k-DCA9-DOX5.5 conjugate comprising dextran of 10kDa, DCA of DS 9 and DOX loading content of 5.5wt%, formed the micelles with the smallest size (110nm). These prodrug micelles could slowly liberate DOX under physiological conditions but efficiently released the drug at an acidified endosomal pH by the hydrolysis of acid-labile hydrazone linker. In vitro cytotoxicity experiment indicated that Dex10k-DCA9-DOX5.5 micelles exerted marked antitumor activity against MCF-7 and SKOV-3 cancer cells. Besides, intravenous administration of the micelles afforded growth inhibition of SKOV-3 tumor bearing in nude mice at a dosage of 2.5mg per kg with anti-cancer efficacy comparable to free DOX-chemotherapy but low systemic toxicity. This study highlights the feasibility of bio-safe and efficient dextran-based prodrug micelles designed for cancer chemotherapy. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Doxorubicin-loaded QuadraSphere microspheres: plasma pharmacokinetics and intratumoral drug concentration in an animal model of liver cancer.

    Science.gov (United States)

    Lee, Kwang-Hun; Liapi, Eleni A; Cornell, Curt; Reb, Philippe; Buijs, Manon; Vossen, Josephina A; Ventura, Veronica Prieto; Geschwind, Jean-Francois H

    2010-06-01

    The purpose of this study was to evaluate, in vitro and in vivo, doxorubicin-loaded poly (vinyl alcohol-sodium acrylate) copolymer microspheres [QuadraSphere microspheres (QSMs)] for transcatheter arterial delivery in an animal model of liver cancer. Doxorubicin loading efficiency and release profile were first tested in vitro. In vivo, 15 rabbits, implanted with a Vx-2 tumor in the liver, were divided into three groups of five rabbits each, based on the time of euthanasia. Twenty-five milligrams of QSMs was diluted in 10 ml of a 10 mg/ml doxorubicin solution and 10 ml of nonionic contrast medium for a total volume of 20 ml. One milliliter of a drug-loaded QSM solution containing 5 mg of doxorubicin was injected into the tumor feeding artery. Plasma doxorubicin and doxorubicinol concentrations, and intratumoral and peritumoral doxorubicin tissue concentrations, were measured. Tumor specimens were pathologically evaluated to record tumor necrosis. As a control, one animal was blandly embolized with plain QSMs in each group. In vitro testing of QSM doxorubicin loadability and release over time showed 82-94% doxorubicin loadability within 2 h and 6% release within the first 6 h after loading, followed by a slow release pattern. In vivo, the doxorubicin plasma concentration declined at 40 min. The peak doxorubicin intratumoral concentration was observed at 3 days and remained detectable till the study's end point (7 days). Mean percentage tumor cell death in the doxorubicin QSM group was 90% at 7 days and 60% in the bland QSM embolization group. In conclusion, QSMs can be efficiently loaded with doxorubicin. Initial experiments with doxorubicin-loaded QSMs show a safe pharmacokinetic profile and effective tumor killing in an animal model of liver cancer.

  14. Doxorubicin-Loaded QuadraSphere Microspheres: Plasma Pharmacokinetics and Intratumoral Drug Concentration in an Animal Model of Liver Cancer

    International Nuclear Information System (INIS)

    Lee, Kwang-Hun; Liapi, Eleni A.; Cornell, Curt; Reb, Philippe; Buijs, Manon; Vossen, Josephina A.; Ventura, Veronica Prieto; Geschwind, Jean-Francois H.

    2010-01-01

    The purpose of this study was to evaluate, in vitro and in vivo, doxorubicin-loaded poly (vinyl alcohol-sodium acrylate) copolymer microspheres [QuadraSphere microspheres (QSMs)] for transcatheter arterial delivery in an animal model of liver cancer. Doxorubicin loading efficiency and release profile were first tested in vitro. In vivo, 15 rabbits, implanted with a Vx-2 tumor in the liver, were divided into three groups of five rabbits each, based on the time of euthanasia. Twenty-five milligrams of QSMs was diluted in 10 ml of a 10 mg/ml doxorubicin solution and 10 ml of nonionic contrast medium for a total volume of 20 ml. One milliliter of a drug-loaded QSM solution containing 5 mg of doxorubicin was injected into the tumor feeding artery. Plasma doxorubicin and doxorubicinol concentrations, and intratumoral and peritumoral doxorubicin tissue concentrations, were measured. Tumor specimens were pathologically evaluated to record tumor necrosis. As a control, one animal was blandly embolized with plain QSMs in each group. In vitro testing of QSM doxorubicin loadability and release over time showed 82-94% doxorubicin loadability within 2 h and 6% release within the first 6 h after loading, followed by a slow release pattern. In vivo, the doxorubicin plasma concentration declined at 40 min. The peak doxorubicin intratumoral concentration was observed at 3 days and remained detectable till the study's end point (7 days). Mean percentage tumor cell death in the doxorubicin QSM group was 90% at 7 days and 60% in the bland QSM embolization group. In conclusion, QSMs can be efficiently loaded with doxorubicin. Initial experiments with doxorubicin-loaded QSMs show a safe pharmacokinetic profile and effective tumor killing in an animal model of liver cancer.

  15. Transgenic Expression of the piRNA-Resistant Masculinizer Gene Induces Female-Specific Lethality and Partial Female-to-Male Sex Reversal in the Silkworm, Bombyx mori.

    Science.gov (United States)

    Sakai, Hiroki; Sumitani, Megumi; Chikami, Yasuhiko; Yahata, Kensuke; Uchino, Keiro; Kiuchi, Takashi; Katsuma, Susumu; Aoki, Fugaku; Sezutsu, Hideki; Suzuki, Masataka G

    2016-08-01

    In Bombyx mori (B. mori), Fem piRNA originates from the W chromosome and is responsible for femaleness. The Fem piRNA-PIWI complex targets and cleaves mRNAs transcribed from the Masc gene. Masc encodes a novel CCCH type zinc-finger protein and is required for male-specific splicing of B. mori doublesex (Bmdsx) transcripts. In the present study, several silkworm strains carrying a transgene, which encodes a Fem piRNA-resistant Masc mRNA (Masc-R), were generated. Forced expression of the Masc-R transgene caused female-specific lethality during the larval stages. One of the Masc-R strains weakly expressed Masc-R in various tissues. Females heterozygous for the transgene expressed male-specific isoform of the Bombyx homolog of insulin-like growth factor II mRNA-binding protein (ImpM) and Bmdsx. All examined females showed a lower inducibility of vitellogenin synthesis and exhibited abnormalities in the ovaries. Testis-like tissues were observed in abnormal ovaries and, notably, the tissues contained considerable numbers of sperm bundles. Homozygous expression of the transgene resulted in formation of the male-specific abdominal segment in adult females and caused partial male differentiation in female genitalia. These results strongly suggest that Masc is an important regulatory gene of maleness in B. mori.

  16. Schedule-dependency of doxorubicin and vinblastine in EAT tumours in mice

    International Nuclear Information System (INIS)

    Auersperg, M.; Pogacnik, A.; Kloboves-Prevodnik, V.; Sersa, G.; Cemazar, M.

    2006-01-01

    Background. Antitumour schedule-dependency of the doxorubicin and vinblastine combination was explored. Materials and methods. Intraperitoneal Ehrlich ascites tumours (EAT) syngeneic to CBA mice were treated with vinblastine or doxorubicin alone, or in combined treatment schedules. Results. Combinations of doxorubicin and vinblastine administered at 48-h, but not at 24-h interval, regardless of the sequence of drugs, significantly reduced the number of tumour cells in the ascites in comparison with all other treatments. In the combined treatment schedules, the predominant morphological changes as well as DNA distribution pattern were dependent on the first drug applied. Regardless of the sequence of the drugs, median survival times of animals did not significantly differ between the treatment groups. Conclusions. The effect of combination of vinblastine and doxorubicin is schedule-dependent. The time interval, but not the sequence of drugs seems to be crucial for the observed effect. The data from preclinical studies are important for planning combined treatment schedules in clinical setting. (author)

  17. Reverse Zymography: Overview and Pitfalls.

    Science.gov (United States)

    Sharma, Kanika; Bhattacharyya, Debasish

    2017-01-01

    Reverse zymography is a technique by which protease inhibitor(s) in a sample could be electrophoretically separated in a substrate-impregnated acrylamide gel and their relative abundance could be semi-quantified. The gel after electrophoresis is incubated with a protease when the impregnated substrate and all other proteins of the sample are degraded into small peptides except the inhibitor(s) that show clear bands against a white background. Since reverse zymography cannot distinguish between a protease inhibitor and a protein that is resistant against proteolysis, the results should be confirmed from inhibition of protease activity by solution state assay.

  18. The lipid lowering drug lovastatin protects against doxorubicin-induced hepatotoxicity

    International Nuclear Information System (INIS)

    Henninger, Christian; Huelsenbeck, Johannes; Huelsenbeck, Stefanie; Grösch, Sabine; Schad, Arno; Lackner, Karl J.; Kaina, Bernd; Fritz, Gerhard

    2012-01-01

    Liver is the main detoxifying organ and therefore the target of high concentrations of genotoxic compounds, such as environmental carcinogens and anticancer drugs. Here, we investigated the usefulness of lovastatin, which is nowadays widely used for lipid lowering purpose, as a hepatoprotective drug following the administration of the anthracycline derivative doxorubicin in vivo. To this end, BALB/c mice were exposed to either a single high dose or three consecutive low doses of doxorubicin. Acute and subacute hepatotoxicities were analyzed with or without lovastatin co-treatment. Lovastatin protected the liver against doxorubicin-induced acute pro-inflammatory and pro-fibrotic stress responses as indicated by an attenuated mRNA expression of tumor necrosis factor alpha (TNFα) and connective tissue growth factor (CTGF), respectively. Hepatoprotection by lovastatin was due to a reduced induction of DNA damage following doxorubicin treatment. The statin also mitigated subacute anthracycline-provoked hepatotoxicity as shown on the level of doxorubicin- and epirubicin-stimulated CTGF mRNA expression as well as histopathologically detectable fibrosis and serum concentration of marker enzymes of hepatotoxicity (GPT/GLDH). Kidney damage following doxorubicin exposure was not detectable under our experimental conditions. Moreover, lovastatin showed multiple inhibitory effects on doxorubicin-triggered hepatic expression of genes involved in oxidative stress response, drug transport, DNA repair, cell cycle progression and cell death. Doxorubicin also stimulated the formation of ceramides. Ceramide production, however, was not blocked by lovastatin, indicating that hepatoprotection by lovastatin is independent of the sphingolipid metabolism. Overall, the data show that lovastatin is hepatoprotective following genotoxic stress induced by anthracyclines. Based on the data, we hypothesize that statins might be suitable to lower hepatic injury following anthracycline

  19. The lipid lowering drug lovastatin protects against doxorubicin-induced hepatotoxicity

    Energy Technology Data Exchange (ETDEWEB)

    Henninger, Christian [Institute of Toxicology, University Medical Center of the Johannes Gutenberg University Mainz, Obere Zahlbacher Str. 67, D-55131 Mainz (Germany); Institute of Toxicology, University Duesseldorf, Medical Faculty, Universitätsstrasse 1, D-40225 Duesseldorf (Germany); Huelsenbeck, Johannes; Huelsenbeck, Stefanie [Institute of Toxicology, University Medical Center of the Johannes Gutenberg University Mainz, Obere Zahlbacher Str. 67, D-55131 Mainz (Germany); Grösch, Sabine [Institute of Clinical Pharmacology, Johann Wolfgang Goethe University Frankfurt, Theodor Stern Kai 7, D-60590 Frankfurt/Main (Germany); Schad, Arno [Institute of Pathology, University Medical Center of the Johannes Gutenberg University Mainz, Obere Zahlbacher Str. 67, D-55131 Mainz (Germany); Lackner, Karl J. [Institute of Clinical Chemistry and Laboratory Medicine, University Medical Center of the Johannes Gutenberg University Mainz, Obere Zahlbacher Str. 67, D-55131 Mainz (Germany); Kaina, Bernd [Institute of Toxicology, University Medical Center of the Johannes Gutenberg University Mainz, Obere Zahlbacher Str. 67, D-55131 Mainz (Germany); Fritz, Gerhard, E-mail: fritz@uni-duesseldorf.de [Institute of Toxicology, University Medical Center of the Johannes Gutenberg University Mainz, Obere Zahlbacher Str. 67, D-55131 Mainz (Germany); Institute of Toxicology, University Duesseldorf, Medical Faculty, Universitätsstrasse 1, D-40225 Duesseldorf (Germany)

    2012-05-15

    Liver is the main detoxifying organ and therefore the target of high concentrations of genotoxic compounds, such as environmental carcinogens and anticancer drugs. Here, we investigated the usefulness of lovastatin, which is nowadays widely used for lipid lowering purpose, as a hepatoprotective drug following the administration of the anthracycline derivative doxorubicin in vivo. To this end, BALB/c mice were exposed to either a single high dose or three consecutive low doses of doxorubicin. Acute and subacute hepatotoxicities were analyzed with or without lovastatin co-treatment. Lovastatin protected the liver against doxorubicin-induced acute pro-inflammatory and pro-fibrotic stress responses as indicated by an attenuated mRNA expression of tumor necrosis factor alpha (TNFα) and connective tissue growth factor (CTGF), respectively. Hepatoprotection by lovastatin was due to a reduced induction of DNA damage following doxorubicin treatment. The statin also mitigated subacute anthracycline-provoked hepatotoxicity as shown on the level of doxorubicin- and epirubicin-stimulated CTGF mRNA expression as well as histopathologically detectable fibrosis and serum concentration of marker enzymes of hepatotoxicity (GPT/GLDH). Kidney damage following doxorubicin exposure was not detectable under our experimental conditions. Moreover, lovastatin showed multiple inhibitory effects on doxorubicin-triggered hepatic expression of genes involved in oxidative stress response, drug transport, DNA repair, cell cycle progression and cell death. Doxorubicin also stimulated the formation of ceramides. Ceramide production, however, was not blocked by lovastatin, indicating that hepatoprotection by lovastatin is independent of the sphingolipid metabolism. Overall, the data show that lovastatin is hepatoprotective following genotoxic stress induced by anthracyclines. Based on the data, we hypothesize that statins might be suitable to lower hepatic injury following anthracycline

  20. Hypothalamic Energy Metabolism Is Impaired By Doxorubicin Independently Of Inflammation In Non-tumour-bearing Rats.

    OpenAIRE

    Antunes, Barbara M M; Lira, Fabio Santos; Pimentel, Gustavo Duarte; Rosa Neto, José Cesar; Esteves, Andrea Maculano; Oyama, Lila Missae; de Souza, Cláudio Teodoro; Gonçalves, Cinara Ludvig; Streck, Emilio Luiz; Rodrigues, Bruno; dos Santos, Ronaldo Vagner; de Mello, Marco Túlio

    2016-01-01

    We sought to explore the effects of doxorubicin on inflammatory profiles and energy metabolism in the hypothalamus of rats. To investigate these effects, we formed two groups: a control (C) group and a Doxorubicin (DOXO) group. Sixteen rats were randomly assigned to either the control (C) or DOXO groups. The hypothalamus was collected. The levels of interleukin (IL)-1β, IL-6, IL-10, TNF-α and energy metabolism (malate dehydrogenase, complex I and III activities) were analysed in the hypothala...

  1. Activity of trypsin-like enzymes and gelatinases in rats with doxorubicin cardiomyopathy

    OpenAIRE

    Iu. А. Gordiienko; Ya. V. Babets; А. О. Kulinich; А. І. Shevtsova; G. О. Ushakova

    2014-01-01

    Activity of trypsin-like enzymes (ATLE) and gelatinases A and B were studied in the blood plasma and extracts from cardiac muscle, cerebral cortex and cerebellum of rats with cardiomyopathy caused by anthracycline antibiotic doxorubicin against the background of preventive application of corvitin and α-ketoglutarate. ATLE significantly increased in blood plasma and extracts from cerebral cortex but decreased in extracts from cardiac muscle and cerebellum in doxorubicin cardiomyopathy (DCMP). ...

  2. Mesenchymal Stem Cells Reduce Left Ventricular Mass in Rats with Doxorubicin-Induced Cardiomyopathy

    OpenAIRE

    Haydardedeoglu, Ali Evren; Boztok Özgermen, Deva Basak; Yavuz, Orhan

    2018-01-01

    SUMMARY: Doxorubicin is a drug that used by a majority in the treatment of carcinomas. The most obvious known side effect is cardiomyopathy. Many studies have been carried out to eliminate side effects of the doxorubicin, and stem cell studies have been added in recent years. In this study, it was aimed to investigate fetal-derived mesenchymal stem cells (F-MSCs) treatment of doxorubicininduced cardiomyopathy by morphological methods. A total of 24 rats which were divided into three separate ...

  3. Studies on the effect of doxorubicin on MDA, NO2, NO3, Se-GSH ...

    African Journals Online (AJOL)

    SERVER

    2007-10-18

    Oct 18, 2007 ... Nitric oxide; NO2. - Nitric oxide; NO3- ... The lipid peroxides were determined by the TBA me- ... Effect of different doses of doxorubicin on rat serum nitrite (NO2 .... 2306. Afr. J. Biotechnol. 0. 5. 10. 15. 20. 25. 30. P e rc e n. t c h a n g e o v e ... Doxorubicin induced percent changes of rat serum Nitrate (NO3.

  4. High fat diet-fed obese rats are highly sensitive to doxorubicin-induced cardiotoxicity

    International Nuclear Information System (INIS)

    Mitra, Mayurranjan S.; Donthamsetty, Shashikiran; White, Brent; Mehendale, Harihara M.

    2008-01-01

    Often, chemotherapy by doxorubicin (Adriamycin) is limited due to life threatening cardiotoxicity in patients during and posttherapy. Recently, we have shown that moderate diet restriction remarkably protects against doxorubicin-induced cardiotoxicity. This cardioprotection is accompanied by decreased cardiac oxidative stress and triglycerides and increased cardiac fatty-acid oxidation, ATP synthesis, and upregulated JAK/STAT3 pathway. In the current study, we investigated whether a physiological intervention by feeding 40% high fat diet (HFD), which induces obesity in male Sprague-Dawley rats (250-275 g), sensitizes to doxorubicin-induced cardiotoxicity. A LD 10 dose (8 mg doxorubicin/kg, ip) administered on day 43 of the HFD feeding regimen led to higher cardiotoxicity, cardiac dysfunction, lipid peroxidation, and 80% mortality in the obese (OB) rats in the absence of any significant renal or hepatic toxicity. Doxorubicin toxicokinetics studies revealed no change in accumulation of doxorubicin and doxorubicinol (toxic metabolite) in the normal diet-fed (ND) and OB hearts. Mechanistic studies revealed that OB rats are sensitized due to: (1) higher oxyradical stress leading to upregulation of uncoupling proteins 2 and 3, (2) downregulation of cardiac peroxisome proliferators activated receptor-α, (3) decreased plasma adiponectin levels, (4) decreased cardiac fatty-acid oxidation (666.9 ± 14.0 nmol/min/g heart in ND versus 400.2 ± 11.8 nmol/min/g heart in OB), (5) decreased mitochondrial AMP-α2 protein kinase, and (6) 86% drop in cardiac ATP levels accompanied by decreased ATP/ADP ratio after doxorubicin administration. Decreased cardiac erythropoietin and increased SOCS3 further downregulated the cardioprotective JAK/STAT3 pathway. In conclusion, HFD-induced obese rats are highly sensitized to doxorubicin-induced cardiotoxicity by substantially downregulating cardiac mitochondrial ATP generation, increasing oxidative stress and downregulating the JAK/STAT3

  5. Doxorubicin-Induced Gut Toxicity in Piglets fed Bovine Milk and Colostrum

    DEFF Research Database (Denmark)

    Shen, René Liang; Rathe, Mathias; Jiang, Pingping

    2016-01-01

    OBJECTIVE: Chemotherapy-induced intestinal toxicity is a common adverse effect of cancer treatment. We hypothesized that a milk diet containing bovine colostrum (BC) would reduce intestinal toxicity in doxorubicin-treated piglets. METHODS: Study 1 investigated intestinal parameters nine days after...... Colostrum supplementation had limited effects on doxorubicin-induced toxicity in milk-fed piglets suggesting that colostrum and a bovine milk diet enriched with whey protein provided similar...

  6. Transarterial chemoembolization using gelatin sponges or microspheres plus lipiodol-doxorubicin versus doxorubicin-loaded beads for the treatment of hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Liu, Yi Sheng; Ou, Ming Ching; Tsai, Yi Shan; Lin, Xi Zhang; Wang, Chien Kuo; Tsai, Hong Ming; Chuang, Ming Tsung

    2015-01-01

    To retrospectively compare treatment of hepatocellular carcinoma (HCC) with transarterial chemoembolization (TACE) using gelatin sponges or microspheres plus lipiodol-doxorubicin vs. doxorubicin-loaded drug-eluting beads (DEB). A total of 158 patients with HCC received TACE from November 2010 to November 2011 were enrolled in this study, including 64 (40.5%) received TACE with lipiodol-doxorubicin and gelatin sponges (group A), 41 (25.9%) received TACE with lipiodol-doxorubicin and microspheres (group B), and 53 (33.5%) received TACE with doxorubicin-loaded DEB (group C). Tumor response and adverse events (AEs) were evaluated. No significant difference was found at baseline among the three groups. The doxorubicin dosage in group C was significantly (p < 0.001) higher compared to the dose used in groups A or B (median, 50 mg vs. 31 mg or 25 mg). Significantly (p < 0.001) more patients in group C achieved complete response compared to those in groups A or B (32.1% vs. 6.3% or 2.4%). Significantly (p < 0.001) less patients in group C had progressive disease compared to those in groups A or B (34.0% vs. 57.8% or 68.3%). Minor AEs were more common in groups A and B compared to group C, with rates of 54.7%, 34.1%, and 5.7%, respectively. In patients with HCC, TACE with DEB offers better safety and efficacy profiles compared to either TACE with gelatin sponges or TACE with microspheres.

  7. Fabrication of doxorubicin nanoparticles by controlled antisolvent precipitation for enhanced intracellular delivery.

    Science.gov (United States)

    Tam, Yu Tong; To, Kenneth Kin Wah; Chow, Albert Hee Lum

    2016-03-01

    Over-expression of ATP-binding cassette transporters is one of the most important mechanisms responsible for multidrug resistance. Here, we aimed to develop a stable polymeric nanoparticle system by flash nanoprecipitation (FNP) for enhanced anticancer drug delivery into drug resistant cancer cells. As an antisolvent precipitation process, FNP works best for highly lipophilic solutes (logP>6). Thus we also aimed to evaluate the applicability of FNP to drugs with relatively low lipophilicity (logP=1-2). To this end, doxorubicin (DOX), an anthracycline anticancer agent and a P-gp substrate with a logP of 1.3, was selected as a model drug for the assessment. DOX was successfully incorporated into the amphiphilic diblock copolymer, polyethylene glycol-b-polylactic acid (PEG-b-PLA), by FNP using a four-stream multi-inlet vortex mixer. Optimization of key processing parameters and co-formulation with the co-stabilizer, polyvinylpyrrolidone, yielded highly stable, roughly spherical DOX-loaded PEG-b-PLA nanoparticles (DOX.NP) with mean particle size below 100nm, drug loading up to 14%, and drug encapsulation efficiency up to 49%. DOX.NP exhibited a pH-dependent drug release profile with higher cumulative release rate at acidic pHs. Surface analysis of DOX.NP by XPS revealed an absence of DOX on the particle surface, indicative of complete drug encapsulation. While there were no significant differences in cytotoxic effect on P-gp over-expressing LCC6/MDR cell line between DOX.NP and free DOX in buffered aqueous media, DOX.NP exhibited a considerably higher cellular uptake and intracellular retention after efflux. The apparent lack of cytotoxicity enhancement with DOX.NP may be attributable to its slow DOX release inside the cells. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Abatement by Naringenin of Doxorubicin-Induced Cardiac Toxicity in Rats

    International Nuclear Information System (INIS)

    Arafa, H.M.; Abd-Ellah, M.F.; Hafez, H.F.

    2005-01-01

    Doxorubicin is one of the most active cytotoxic agents in current use. It has proven efficacy in various malignancies either alone or combined with other cytocidal agents. The clinical usefulness of the anthracycline drug has been precluded by cardiac toxicity. Many therapeutic interventions have been attempted to improve the therapeutic benefits of the drug. Few, however, have been efficacious in this setting. Purpose: We have addressed in the current study the possible protective effects of naringenin, a flavonoid known to have anti-oxidant properties, on doxorubicin induced cardiac toxicity in male Swiss albino rats. Methods: Forty male Swiss albino rats were used in this study. Naringenin (25 mg/kg body weight) was administered daily by gavage for 7 consecutive days before a cumulative single dose of doxorubicin (15 mg/kg body weight, ip). Doxorubicin induced marked biochemical alterations characteristic of cardiac toxicity including, elevated activities of serum total lactate dehydrogenase (LDH) and creatine phosphokinase (CPK), enhanced lipid peroxidation measured as malonaldehyde (MDA). The anthracycline drug has also reduced the cardiac enzymatic activities of superoxide dismutase (SOD), glutathione-Stransferase (GST) and catalase (CAT). Besides, it reduced significantly the reduced glutathione (GSH) level, but it increased the total NO content in heart tissue. Prior administration of naringenin ahead of doxorubicin challenge ameliorated all these biochemical markers. Taken together, one could conclude that naringenin has a protective role in the abatement of doxorubicin-induced cardiac toxicity that resides, at least in part, on its anti-radical effects and regulatory role on NO production

  9. Effects of Streptococcus thermophilus TH-4 in a rat model of doxorubicin-induced mucositis.

    Science.gov (United States)

    Wang, Hanru; Brook, Caitlin L; Whittaker, Alexandra L; Lawrence, Andrew; Yazbeck, Roger; Howarth, Gordon S

    2013-08-01

    Mucositis is a debilitating intestinal side effect of chemotherapeutic regimens. Probiotics have been considered a possible preventative treatment for mucositis. Streptococcus thermophilus TH-4 (TH-4), a newly identified probiotic, has been shown to partially alleviate mucositis induced by administration of the antimetabolite chemotherapy drug, methotrexate in rats; likely mediated through a mechanism of folate production. However, its effects against other classes of chemotherapy drug have yet to be determined. The authors investigated the effects of TH-4 in a rat model of mucositis induced by the anthracycline chemotherapy drug, doxorubicin. Gastrointestinal damage was induc