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Berlin Brandenburg

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  • 2016  (14)
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  • 2016  (14)
  • 1
    Language: English
    In: Oncotarget, 06 September 2016, Vol.7(36), pp.58051-58064
    Description: The CDK inhibitor SNS-032 had previously exerted promising anti-neuroblastoma activity via CDK7 and 9 inhibition. ABCB1 expression was identified as major determinant of SNS-032 resistance. Here, we investigated the role of ABCB1 in acquired SNS-032 resistance. In contrast to ABCB1-expressing UKF-NB-3 sub-lines resistant to other ABCB1 substrates, SNS-032-adapted UKF-NB-3 (UKF-NB-3rSNS- 032300nM) cells remained sensitive to the non-ABCB1 substrate cisplatin and were completely re-sensitized to cytotoxic ABCB1 substrates by ABCB1 inhibition. Moreover, UKF-NB-3rSNS-032300nM cells remained similarly sensitive to CDK7 and 9 inhibition as UKF-NB-3 cells. In contrast, SHEPrSNS-0322000nM, the SNS-032-resistant sub-line of the neuroblastoma cell line SHEP, displayed low level SNS-032 resistance also when ABCB1 was inhibited. This discrepancy may be explained by the higher SNS-032 concentrations that were used to establish SHEPrSNS-0322000nM cells, since SHEP cells intrinsically express ABCB1 and are less sensitive to SNS-032 (IC50 912 nM) than UKF-NB-3 cells (IC50 153 nM). In conclusion, we show that ABCB1 expression represents the primary (sometimes exclusive) resistance mechanism in neuroblastoma cells with acquired resistance to SNS-032. Thus, ABCB1 inhibitors may increase the SNS-032 efficacy in ABCB1-expressing cells and prolong or avoid resistance formation.
    Keywords: Abcb1 ; Cdk Inhibitor ; Cancer ; Multi-Drug Resistance ; Neuroblastoma ; Drug Resistance, Neoplasm ; Antineoplastic Agents -- Pharmacology ; Neuroblastoma -- Drug Therapy ; Oxazoles -- Pharmacology ; Protein Kinase Inhibitors -- Pharmacology ; Thiazoles -- Pharmacology
    E-ISSN: 1949-2553
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  • 2
    In: Schneider, Constanze and Oellerich, Thomas and Baldauf, Hanna-Mari and Schwarz, Sarah-Marie and Thomas, Dominique and Flick, Robert and Bohnenberger, Hanibal and Kaderali, Lars and Stegmann, Lena and Cremer, Anjali and Martin, Margarethe and Lohmeyer, Julian and Michaelis, Martin and Hornung, Veit and Schliemann, Christoph and Berdel, Wolfgang E and Hartmann, Wolfgang and Wardelmann, Eva and Comoglio, Federico and Hansmann, Martin-Leo and Yakunin, Alexander F and Geisslinger, Gerd and Ströbel, Philipp and Ferreirós, Nerea and Serve, Hubert and Keppler, Oliver T and Cinatl, Jindrich (2016) SAMHD1 is a biomarker for cytarabine response and a therapeutic target in acute myeloid leukemia. Nature medicine, 23 (2). pp. 250-255.
    Description: The nucleoside analog cytarabine (Ara-C) is an essential component of primary and salvage chemotherapy regimens for acute myeloid leukemia (AML). After cellular uptake, Ara-C is converted into its therapeutically active triphosphate metabolite, Ara-CTP, which exerts antileukemic effects, primarily by inhibiting DNA synthesis in proliferating cells. Currently, a substantial fraction of patients with AML fail to respond effectively to Ara-C therapy, and reliable biomarkers for predicting the therapeutic response to Ara-C are lacking. SAMHD1 is a deoxynucleoside triphosphate (dNTP) triphosphohydrolase that cleaves physiological dNTPs into deoxyribonucleosides and inorganic triphosphate. Although it has been postulated that SAMHD1 sensitizes cancer cells to nucleoside-analog derivatives through the depletion of competing dNTPs, we show here that SAMHD1 reduces Ara-C cytotoxicity in AML cells. Mechanistically, dGTP-activated SAMHD1 hydrolyzes Ara-CTP, which results in a drastic reduction of Ara-CTP in leukemic cells. Loss of SAMHD1 activity-through genetic depletion, mutational inactivation of its triphosphohydrolase activity or proteasomal degradation using specialized, virus-like particles-potentiates the cytotoxicity of Ara-C in AML cells. In mouse models of retroviral AML transplantation, as well as in retrospective analyses of adult patients with AML, the response to Ara-C-containing therapy was inversely correlated with SAMHD1 expression. These results identify SAMHD1 as a potential biomarker for the stratification of patients with AML who might best respond to Ara-C-based therapy and as a target for treating Ara-C-refractory AML.
    Keywords: RM Therapeutics. Pharmacology
    ISSN: 1078-8956
    Source: University of Kent
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  • 3
    In: Nature Medicine, 2016
    Description: The nucleoside analog cytarabine (Ara-C) is an essential component of primary and salvage chemotherapy regimens for acute myeloid leukemia (AML). After cellular uptake, Ara-C is converted into its therapeutically active triphosphate metabolite, Ara-CTP, which exerts antileukemic effects, primarily by inhibiting DNA synthesis in proliferating cells1. Currently, a substantial fraction of patients with AML fail to respond effectively to Ara-C therapy, and reliable biomarkers for predicting the therapeutic response to Ara-C are lacking2, 3. SAMHD1 is a deoxynucleoside triphosphate (dNTP) triphosphohydrolase that cleaves physiological dNTPs into deoxyribonucleosides and inorganic triphosphate4, 5. Although it has been postulated that SAMHD1 sensitizes cancer cells to nucleoside-analog derivatives through the depletion of competing dNTPs6, we show here that SAMHD1 reduces Ara-C cytotoxicity in AML cells. Mechanistically, dGTP-activated SAMHD1 hydrolyzes Ara-CTP, which results in a drastic reduction of Ara-CTP in leukemic cells. Loss of SAMHD1 activity--through genetic depletion, mutational inactivation of its triphosphohydrolase activity or proteasomal degradation using specialized, virus-like particles7, 8--potentiates the cytotoxicity of Ara-C in AML cells. In mouse models of retroviral AML transplantation, as well as in retrospective analyses of adult patients with AML, the response to Ara-C-containing therapy was inversely correlated with SAMHD1 expression. These results identify SAMHD1 as a potential biomarker for the stratification of patients with AML who might best respond to Ara-C-based therapy and as a target for treating Ara-C-refractory AML.
    Keywords: Leukemia ; Chemotherapy ; Biomarkers ; Medical Prognosis ; Cytotoxicity;
    ISSN: 1078-8956
    E-ISSN: 1546-170X
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  • 4
    In: Löschmann, Nadine and Michaelis, Martin and Rothweiler, Florian and Voges, Yvonne and Balónová, Barbora and Blight, Barry A. and Cinatl, Jindrich (2016) ABCB1 as predominant resistance mechanism in cells with acquired SNS-032 resistance. Oncotarget, 7 (36). pp. 58051-58064.
    Description: The CDK inhibitor SNS-032 had previously exerted promising anti-neuroblastoma activity via CDK7 and 9 inhibition. ABCB1 expression was identified as major determinant of SNS-032 resistance. Here, we investigated the role of ABCB1 in acquired SNS-032 resistance. In contrast to ABCB1-expressing UKF-NB-3 sub-lines resistant to other ABCB1 substrates, SNS-032-adapted UKF-NB-3 (UKF-NB-3rSNS- 032300nM) cells remained sensitive to the non-ABCB1 substrate cisplatin and were completely re-sensitized to cytotoxic ABCB1 substrates by ABCB1 inhibition. Moreover, UKF-NB-3rSNS-032300nM cells remained similarly sensitive to CDK7 and 9 inhibition as UKF-NB-3 cells. In contrast, SHEPrSNS-0322000nM, the SNS-032-resistant sub-line of the neuroblastoma cell line SHEP, displayed low level SNS-032 resistance also when ABCB1 was inhibited. This discrepancy may be explained by the higher SNS-032 concentrations that were used to establish SHEPrSNS-0322000nM cells, since SHEP cells intrinsically express ABCB1 and are less sensitive to SNS-032 (IC50 912 nM) than UKF-NB-3 cells (IC50 153 nM). In conclusion, we show that ABCB1 expression represents the primary (sometimes exclusive) resistance mechanism in neuroblastoma cells with acquired resistance to SNS-032. Thus, ABCB1 inhibitors may increase the SNS-032 efficacy in ABCB1-expressing cells and prolong or avoid resistance formation.
    Keywords: RM Therapeutics. Pharmacology
    ISSN: 1949-2553
    Source: University of Kent
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  • 5
    In: Sarin, Navin and Engel, Florian and Kalayda, Ganna V and Frötschl, Roland and Cinatl, Jindrich and Rothweiler, Florian and Michaelis, Martin and Fröhlich, Holger and Jaehde, Ulrich (2016) Knowledge-based approach to identify key determinants of cisplatin sensitivity . International journal of clinical pharmacology and therapeutics, .
    Keywords: RM Therapeutics. Pharmacology
    ISSN: 0946-1965
    Source: University of Kent
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  • 6
    Language: English
    In: Oncotarget, 08 March 2016, Vol.7(10), pp.11664-76
    Description: Pirinixic acid derivatives, a new class of drug candidates for a range of diseases, interfere with targets including PPARα, PPARγ, 5-lipoxygenase (5-LO), and microsomal prostaglandin and E2 synthase-1 (mPGES1). Since 5-LO, mPGES1, PPARα, and PPARγ represent potential anti-cancer drug targets, we here investigated the effects of 39 pirinixic acid derivatives on prostate cancer (PC-3) and neuroblastoma (UKF-NB-3) cell viability and, subsequently, the effects of selected compounds on drug-resistant neuroblastoma cells. Few compounds affected cancer cell viability in low micromolar concentrations but there was no correlation between the anti-cancer effects and the effects on 5-LO, mPGES1, PPARα, or PPARγ. Most strikingly, pirinixic acid derivatives interfered with drug transport by the ATP-binding cassette (ABC) transporter ABCB1 in a drug-specific fashion. LP117, the compound that exerted the strongest effect on ABCB1, interfered in the investigated concentrations of up to 2μM with the ABCB1-mediated transport of vincristine, vinorelbine, actinomycin D, paclitaxel, and calcein-AM but not of doxorubicin, rhodamine 123, or JC-1. In silico docking studies identified differences in the interaction profiles of the investigated ABCB1 substrates with the known ABCB1 binding sites that may explain the substrate-specific effects of LP117. Thus, pirinixic acid derivatives may offer potential as drug-specific modulators of ABCB1-mediated drug transport.
    Keywords: Abcb1 ; Cancer ; Drug Resistance ; Pirinixic Acid ; Pirinixic Acid Derivative ; Pyrimidines -- Pharmacology
    E-ISSN: 1949-2553
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  • 7
    In: Journal of Emerging Diseases and Virology, 2016, Vol.1(1)
    ISSN: Journal of Emerging Diseases and Virology
    E-ISSN: 24731846
    Source: CrossRef
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  • 8
    In: Voges, Yvonne and Michaelis, Martin and Rothweiler, Florian and Schaller, Torsten and Schneider, Constanze and Politt, Katharina and Mernberger, Marco and Nist, Andrea and Stiewe, Thorsten and Wass, Mark N. and Rödel, Franz and Cinatl, Jindrich (2016) Effects of YM155 on survivin levels and viability in neuroblastoma cells with acquired drug resistance. Cell death & disease, 7 (10). e2410.
    Description: Resistance formation after initial therapy response (acquired resistance) is common in high-risk neuroblastoma patients. YM155 is a drug candidate that was introduced as a survivin suppressant. This mechanism was later challenged, and DNA damage induction and Mcl-1 depletion were suggested instead. Here we investigated the efficacy and mechanism of action of YM155 in neuroblastoma cells with acquired drug resistance. The efficacy of YM155 was determined in neuroblastoma cell lines and their sublines with acquired resistance to clinically relevant drugs. Survivin levels, Mcl-1 levels, and DNA damage formation were determined in response to YM155. RNAi-mediated depletion of survivin, Mcl-1, and p53 was performed to investigate their roles during YM155 treatment. Clinical YM155 concentrations affected the viability of drug-resistant neuroblastoma cells through survivin depletion and p53 activation. MDM2 inhibitor-induced p53 activation further enhanced YM155 activity. Loss of p53 function generally affected anti-neuroblastoma approaches targeting survivin. Upregulation of ABCB1 (causes YM155 efflux) and downregulation of SLC35F2 (causes YM155 uptake) mediated YM155-specific resistance. YM155-adapted cells displayed increased ABCB1 levels, decreased SLC35F2 levels, and a p53 mutation. YM155-adapted neuroblastoma cells were also characterized by decreased sensitivity to RNAi-mediated survivin depletion, further confirming survivin as a critical YM155 target in neuroblastoma. In conclusion, YM155 targets survivin in neuroblastoma. Furthermore, survivin is a promising therapeutic target for p53 wild-type neuroblastomas after resistance acquisition (neuroblastomas are rarely p53-mutated), potentially in combination with p53 activators. In addition, we show that the adaptation of cancer cells to molecular-targeted anticancer drugs is an effective strategy to elucidate a drug's mechanism of action.
    Keywords: RM Therapeutics. Pharmacology
    ISSN: 2041-4889
    Source: University of Kent
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  • 9
    Language: English
    In: European Journal of Pharmaceutical Sciences, 30 October 2016, Vol.94, pp.20-32
    Description: Drug treatment of epidermal growth factor receptor (EGFR) positive non-small cell lung cancer has improved substantially by targeting activating mutations within the receptor tyrosine kinase domain. However, the development of drug resistance still limits this approach. As root causes, large heterogeneity between tumour entities but also within tumour cells have been suggested. Therefore, approaches to identify these multitude and complex mechanisms are urgently required. Affinity purification coupled with high resolution mass spectrometry was applied to isolate and characterise the EGFR interactome from HCC4006 non-small cell lung cancer cells and their variant HCC4006 ERLO adapted to grow in the presence of therapeutically relevant concentrations of erlotinib. Bioinformatics analyses were carried out to identify proteins and their related molecular functions that interact differentially with EGFR in the untreated state or when incubated with erlotinib prior to EGFR activation. Across all experimental conditions 375 proteins were detected to participate in the EGFR interactome, 90% of which constituted a complex protein interaction network that was bioinformatically reconstructed from literature data. Treatment of HCC4006 ERLO cells carrying a resistance phenotype to erlotinib was associated with an increase of protein levels of members of the clathrin-associated adaptor protein family AP2 (AP2A1, AP2A2, AP2B1), structural proteins of cytoskeleton rearrangement as well as signalling molecules such as Shc. Validation experiments confirmed activation of the Ras-Raf-Mek-Erk (MAPK)-pathway, of which Shc is an initiating adaptor molecule, in HCC4006 ERLO cells. Taken together, differential proteins in the EGFR interactome of HCC4006 ERLO cells were identified that could be related to multiple resistance mechanisms including alterations in growth factor receptor expression, cellular remodelling processes suggesting epithelial-to-mesenchymal transition as well as alterations in downstream signalling. Knowledge of these mechanisms is a pivotal step to build an integrative model of drug resistance in a systems pharmacology manner and to be able to investigate the interplay of these mechanisms and ultimately recommend combinatorial treatment strategies to overcome drug resistance.
    Keywords: Egfr ; Lung Cancer ; Drug Resistance ; Tyrosine Kinase Inhibitors ; Interactome ; Systems Pharmacology ; Pharmacy, Therapeutics, & Pharmacology
    ISSN: 0928-0987
    E-ISSN: 1879-0720
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  • 10
    In: Vallo, Stefan and Michaelis, Martin and Gust, Kilian M and Black, Peter C and Rothweiler, Florian and Kvasnicka, Hans-Michael and Blaheta, Roman A and Brandt, Maximilian P and Wezel, Felix and Haferkamp, Axel and Cinatl, Jindrich (2016) Dasatinib enhances tumor growth in gemcitabine-resistant orthotopic bladder cancer xenografts. BMC research notes, 9 (1). p. 454.
    Description: BACKGROUND Systemic chemotherapy with gemcitabine and cisplatin is standard of care for patients with metastatic urothelial bladder cancer. However, resistance formation is common after initial response. The protein Src is known as a proto-oncogene, which is overexpressed in various human cancers. Since there are controversial reports about the role of Src in bladder cancer, we evaluated the efficacy of the Src kinase inhibitor dasatinib in the urothelial bladder cancer cell line RT112 and its gemcitabine-resistant sub-line RT112(r)GEMCI(20) in vitro and in vivo. METHODS RT112 urothelial cancer cells were adapted to growth in the presence of 20 ng/ml gemcitabine (RT112(r)GEMCI(20)) by continuous cultivation at increasing drug concentrations. Cell viability was determined by MTT assay, cell growth kinetics were determined by cell count, protein levels were measured by western blot, and cell migration was evaluated by scratch assays. In vivo tumor growth was tested in a murine orthotopic xenograft model using bioluminescent imaging. RESULTS Dasatinib exerted similar effects on Src signaling in RT112 and RT112(r)GEMCI(20) cells but RT112(r)GEMCI(20) cells were less sensitive to dasatinib-induced anti-cancer effects (half maximal inhibitory concentration (IC50) of dasatinib in RT112 cells: 349.2 ± 67.2 nM; IC50 of dasatinib in RT112(r)GEMCI(20) cells: 1081.1 ± 239.2 nM). Dasatinib inhibited migration of chemo-naive and gemcitabine-resistant cells. Most strikingly, dasatinib treatment reduced RT112 tumor growth and muscle invasion in orthotopic xenografts, while it was associated with increased size and muscle-invasive growth in RT112(r)GEMCI(20) tumors. CONCLUSION Dasatinib should be considered with care for the treatment of urothelial cancer, in particular for therapy-refractory cases.
    Keywords: RM Therapeutics. Pharmacology
    ISSN: 1756-0500
    Source: University of Kent
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