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Berlin Brandenburg

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  • 1
    Language: English
    In: Pharmacogenomics, September 2010, Vol.11(9), pp.1189-91
    Keywords: Neoplasms -- Drug Therapy ; Protein Kinase Inhibitors -- Therapeutic Use ; Sirolimus -- Therapeutic Use ; Tor Serine-Threonine Kinases -- Antagonists & Inhibitors
    ISSN: 14622416
    E-ISSN: 1744-8042
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  • 2
    Language: English
    In: PLoS ONE, 01 January 2014, Vol.9(1), p.e84417
    Description: Malignant melanoma is a life-threatening skin cancer increasingly diagnosed in the western world. In advanced disease the prognosis is grave. Growth and metastasis formation in melanomas are regulated by a network of cytokines, cytokine-receptors, and adhesion molecules. However, little is known about surface antigens and target expression profiles in human melanomas. We examined the cell surface antigen profile of human skin melanoma cells by multicolor flow cytometry, and compared their phenotype with 4 melanoma cell lines (A375, 607B, Mel-Juso, SK-Mel28). Melanoma cells were defined as CD45-/CD31- cells co-expressing one or more melanoma-related antigens (CD63, CD146, CD166). In most patients, melanoma cells exhibited ErbB3/Her3, CD44/Pgp-1, ICAM-1/CD54 and IGF-1-R/CD221, but did not express CD20, ErbB2/Her2, KIT/CD117, AC133/CD133 or MDR-1/CD243. Melanoma cell lines were found to display a similar phenotype. In most patients, a distinct subpopulation of melanoma cells (4-40%) expressed the erythropoietin receptor (EPO-R) and ErbB4 together with PD-1 and NGF-R/CD271. Both the EPO-R+ and EPO-R- subpopulations produced melanoma lesions in NOD/SCID IL-2Rgamma(null) (NSG) mice in first and secondary recipients. Normal skin melanocytes did not express ErbB4 or EPO-R, but expressed a functional KIT receptor (CD117) as well as NGF-R, ErbB3/Her3, IGF-1-R and CD44. In conclusion, melanoma cells display a unique composition of surface target antigens and cytokine receptors. Malignant transformation of melanomas is accompanied by loss of KIT and acquisition of EPO-R and ErbB4, both of which are co-expressed with NGF-R and PD-1 in distinct subfractions of melanoma cells. However, expression of EPO-R/ErbB4/PD-1 is not indicative of a selective melanoma-initiating potential.
    Keywords: Sciences (General)
    E-ISSN: 1932-6203
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  • 3
    Language: English
    In: PLoS ONE, 2012, Vol.7(1), p.e29925
    Description: The phosphoinositide 3-kinase (PI3-kinase) and the mammalian target of rapamycin (mTOR) are two major signaling molecules involved in growth and activation of mast cells (MC) and basophils (BA). We examined the effects of the dual PI3-kinase/mTOR blocker NVP-BEZ235 on growth of normal and neoplastic BA and MC as well as immunoglobulin E (IgE)-dependent cell activation. Growth of MC and BA were determined by measuring 3 H-thymidine uptake and apoptosis. Cell activation was determined in histamine release experiments and by measuring upregulation of CD63 and CD203c after challenging with IgE plus anti-IgE or allergen. We found that NVP-BEZ235 exerts profound inhibitory effects on growth of primary and cloned neoplastic MC. In the MC leukemia cell line HMC-1, NVP-BEZ235 showed similar IC 50 values in the HMC-1.1 subclone lacking KIT D816V (0.025 µM) and the HMC-1.2 subclone expressing KIT D816V (0.005 µM). Moreover, NVP-BEZ235 was found to exert strong growth-inhibitory effects on neoplastic MC in a xenotransplant-mouse model employing NMR1-Foxn1 nu mice. NVP-BEZ235 also exerted inhibitory effects on cytokine-dependent differentiation of normal BA and MC, but did not induce growth inhibition or apoptosis in mature MC or normal bone marrow cells. Finally, NVP-BEZ235 was found to inhibit IgE-dependent histamine release in BA and MC (IC 50 0.5–1 µM) as well as anti-IgE-induced upregulation of CD203c in BA and IgE-dependent upregulation of CD63 in MC. In summary, NVP-BEZ235 produces growth-inhibitory effects in immature neoplastic MC and inhibits IgE-dependent activation of mature BA and MC. Whether these potentially beneficial drug effects have clinical implications is currently under investigation.
    Keywords: Research Article ; Biology ; Immunology ; Molecular Biology ; Cell Biology ; Developmental Biology
    E-ISSN: 1932-6203
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  • 4
    Language: English
    In: Clinical cancer research : an official journal of the American Association for Cancer Research, 15 August 2011, Vol.17(16), pp.5322-32
    Description: In this study, we tested the antitumor activity of the dual phosphoinositide 3-kinase (PI3K)/mTOR inhibitor BEZ235 against gastric cancer in vitro and in vivo. Gastric cancer cell lines (N87, MKN45, and MKN28) were incubated with BEZ235 and assessed for cell viability, cell cycle, and PI3K/mTOR target inhibition. In vivo, athymic nude mice were inoculated with N87, MKN28, or MKN45 cells and treated daily with BEZ235. 3'-Deoxy-3'-[(18)F]fluorothymidine ([(18)F]FLT) uptake was measured via small animal positron emission tomography (PET). In vitro, BEZ235 dose dependently decreased the cell viability of gastric cancer cell lines. The antiproliferative activity of BEZ235 was linked to a G(1) cell-cycle arrest. In vivo, BEZ235 treatment resulted in PI3K/mTOR target inhibition as shown by dephosphorylation of AKT and S6 protein in all xenograft models. However, BEZ235 treatment only inhibited tumor growth of N87 xenografts, whereas no antitumor effect was observed in the MKN28 and MKN45 xenograft models. Sensitivity to BEZ235 in vivo correlated with downregulation of the proliferation marker thymidine kinase 1. Accordingly, [(18)F]FLT uptake was only significantly reduced in the BEZ235-sensitive N87 xenograft model as measured by PET. In conclusion, in vivo sensitivity of gastric cancer xenografts to BEZ235 did not correlate with in vitro antiproliferative activity or in vivo PI3K/mTOR target inhibition by BEZ235. In contrast, [(18)F]FLT uptake was linked to BEZ235 in vivo sensitivity. Noninvasive [(18)F]FLT PET imaging might qualify as a novel marker for optimizing future clinical testing of dual PI3K/mTOR inhibitors.
    Keywords: Xenograft Model Antitumor Assays ; Imidazoles -- Pharmacology ; Phosphatidylinositol 3-Kinases -- Antagonists & Inhibitors ; Quinolines -- Pharmacology ; Stomach Neoplasms -- Drug Therapy ; Tor Serine-Threonine Kinases -- Antagonists & Inhibitors
    ISSN: 1078-0432
    E-ISSN: 15573265
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  • 5
    In: Journal of Investigative Dermatology, 2010, Vol.131(2), p.495
    Description: The phosphatidyl inositol 3-kinase/mammalian target of rapamycin (PI3K/mTOR) pathway has been shown to be involved in the development of melanoma. PI-103 is a kinase inhibitor blocking PI3K class IA and mTOR complex 1 and 2. Here, we studied the effect of targeting the PI3K/mTORC1/mTORC2 pathway by PI-103 and rapamycin in melanoma cells and in a melanoma mouse model. Dual targeting of PI3K and mTOR by PI-103 induced apoptosis and cell-cycle arrest, and inhibited viability of melanoma cells in vitro. Combined treatment with PI-103 and the prototypic mTORC1 inhibitor rapamycin led to the synergistic suppression of AKT and ribosomal S6 protein phosphorylation and to the induction of apoptosis. In vivo, PI-103 and rapamycin displayed only modest single-agent activity, but the combination significantly reduced the tumor growth compared with both single agents. These data show that blocking the PI3K/mTORC1/mTORC2 pathway using the combination of two distinct small-molecule inhibitors ("vertical inhibition") leads to superior efficacy against malignant melanoma in vitro and in vivo.
    Keywords: Animals–Pharmacology ; Antibiotics, Antineoplastic–Drug Effects ; Apoptosis–Physiology ; Apoptosis–Drug Effects ; Cell Cycle–Physiology ; Cell Cycle–Drug Effects ; Cell Line, Tumor–Drug Effects ; Cell Proliferation–Physiology ; Cell Survival–Pharmacology ; Cell Survival–Pharmacology ; Disease Models, Animal–Metabolism ; Enzyme Inhibitors–Pathology ; Female–Physiopathology ; Furans–Antagonists & Inhibitors ; Humans–Metabolism ; Melanoma–Antagonists & Inhibitors ; Melanoma–Metabolism ; Melanoma–Pharmacology ; Mice–Pharmacology ; Mice, Nude–Drug Effects ; Multiprotein Complexes–Physiology ; Phosphatidylinositol 3-Kinases–Pharmacology ; Phosphatidylinositol 3-Kinases–Metabolism ; Proteins–Pathology ; Proteins–Physiopathology ; Pyridines–Antagonists & Inhibitors ; Pyrimidines–Metabolism ; Signal Transduction–Metabolism ; Signal Transduction–Metabolism ; Sirolimus–Metabolism ; Skin Neoplasms–Metabolism ; Skin Neoplasms–Metabolism ; Skin Neoplasms–Metabolism ; Tor Serine-Threonine Kinases–Metabolism ; Trans-Activators–Metabolism ; Trans-Activators–Metabolism ; Transcription Factors–Metabolism ; Transplantation, Heterologous–Metabolism ; Antibiotics, Antineoplastic ; Crtc2 Protein, Mouse ; Enzyme Inhibitors ; Furans ; Multiprotein Complexes ; Pi103 ; Proteins ; Pyridines ; Pyrimidines ; Trans-Activators ; Transcription Factors ; Mechanistic Target of Rapamycin Complex 1 ; Phosphatidylinositol 3-Kinases ; Tor Serine-Threonine Kinases ; Sirolimus;
    ISSN: 0022-202X
    E-ISSN: 15231747
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  • 6
    Language: English
    In: European Journal of Nuclear Medicine and Molecular Imaging, 2012, Vol.39(1), pp.149-159
    Description: Byline: Thomas Wanek (1), Claudia Kuntner (1), Jens P. Bankstahl (2), Marion Bankstahl (2), Johann Stanek (1,3), Michael Sauberer (1), Severin Mairinger (1,3,4), Sabine Strommer (3), Volker Wacheck (3), Wolfgang Loscher (2), Thomas Erker (4), Markus Muller (3), Oliver Langer (1,3) Keywords: Multidrug resistance; P-glycoprotein; Positron emission tomography; [[.sup.11]C]Tariquidar; [[.sup.11]C]Elacridar; (R)[-[.sup.11]C]Verapamil Abstract: Purpose One important mechanism for chemoresistance of tumours is overexpression of the adenosine triphosphate-binding cassette transporter P-glycoprotein (Pgp). Pgp reduces intracellular concentrations of chemotherapeutic drugs. The aim of this study was to compare the suitability of the radiolabelled Pgp inhibitors [[.sup.11]C]tariquidar and [[.sup.11]C]elacridar with the Pgp substrate radiotracer (R)[-[.sup.11]C]verapamil for discriminating tumours expressing low and high levels of Pgp using small-animal PET imaging in a murine breast cancer model. Methods Murine mammary carcinoma cells (EMT6) were continuously exposed to doxorubicin to generate a Pgp-overexpressing, doxorubicin-resistant cell line (EMT6AR1.0 cells). Both cell lines were subcutaneously injected into female athymic nude mice. One week after implantation, animals underwent PET scans with [[.sup.11]C]tariquidar (n=7), [[.sup.11]C]elacridar (n=6) and (R)[-[.sup.11]C]verapamil (n=7), before and after administration of unlabelled tariquidar (15 mg/kg). Pgp expression in tumour grafts was evaluated by Western blotting. Results [11C]Tariquidar showed significantly higher retention in Pgp-overexpressing EMT6AR1.0 compared with EMT6 tumours: the mean+-SD areas under the time--activity curves in scan 1 from time 0 to 60 min (AUC.sub.0--60) were 38.8+-2.2 min and 25.0+-5.3 min (p=0.016, Wilcoxon matched pairs test). [[.sup.11]C]Elacridar and (R)[-[.sup.11]C]verapamil were not able to discriminate Pgp expression in tumour models. Following administration of unlabelled tariquidar, both EMT6Ar1.0 and EMT6 tumours showed increases in uptake of [[.sup.11]C]tariquidar, [[.sup.11]C]elacridar and (R)[-[.sup.11]C]verapamil. Conclusion Among the tested radiotracers, [[.sup.11]C]tariquidar performed best in discriminating tumours expressing high and low levels of Pgp. Therefore [[.sup.11]C]tariquidar merits further investigation as a PET tracer to assess Pgp expression levels in solid tumours. Author Affiliation: (1) Health & Environment Department, Molecular Medicine, AIT Austrian Institute of Technology GmbH, 2444, Seibersdorf, Austria (2) Department of Pharmacology, Toxicology & Pharmacy, University of Veterinary Medicine Hannover, Hannover, Germany (3) Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria (4) Department of Medicinal Chemistry, University of Vienna, Vienna, Austria Article History: Registration Date: 09/09/2011 Received Date: 24/05/2011 Accepted Date: 09/09/2011 Online Date: 08/10/2011 Article note: Electronic supplementary material The online version of this article (doi: 10.1007/s00259-011-1941-7) contains supplementary material, which is available to authorized users.
    Keywords: Multidrug resistance ; P-glycoprotein ; Positron emission tomography ; [C]Tariquidar ; [C]Elacridar ; ()-[C]Verapamil
    ISSN: 1619-7070
    E-ISSN: 1619-7089
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  • 7
    Language: English
    In: Clinical cancer research : an official journal of the American Association for Cancer Research, 01 December 2014, Vol.20(23), pp.6059-70
    Description: MET, the receptor for hepatocyte growth factor (HGF), has been implicated in driving tumor proliferation and metastasis. High MET expression is correlated with poor prognosis in multiple cancers. Activation of MET can be induced either by HGF-independent mechanisms such as gene amplification, specific genetic mutations, and transcriptional upregulation or by HGF-dependent autocrine or paracrine mechanisms. Here, we report on LY2875358, a novel humanized bivalent anti-MET antibody that has high neutralization and internalization activities, resulting in inhibition of both HGF-dependent and HGF-independent MET pathway activation and tumor growth. In contrast to other bivalent MET antibodies, LY2875358 exhibits no functional agonist activity and does not stimulate biologic activities such as cell proliferation, scattering, invasion, tubulogenesis, or apoptosis protection in various HGF-responsive cells and no evidence of inducing proliferation in vivo in a monkey toxicity study. LY2875358 blocks HGF binding to MET and HGF-induced MET phosphorylation and cell proliferation. In contrast to the humanized one-armed 5D5 anti-MET antibody, LY2875358 induces internalization and degradation of MET that inhibits cell proliferation and tumor growth in models where MET is constitutively activated. Moreover, LY2875358 has potent antitumor activity in both HGF-dependent and HGF-independent (MET-amplified) xenograft tumor models. Together, these findings indicate that the mechanism of action of LY2875358 is different from that of the one-armed MET antibody. LY2875358 may provide a promising therapeutic strategy for patients whose tumors are driven by both HGF-dependent and HGF-independent MET activation. LY2875358 is currently being investigated in multiple clinical studies.
    Keywords: Antibodies, Monoclonal -- Pharmacology ; Antibodies, Monoclonal, Humanized -- Pharmacology ; Antibodies, Neutralizing -- Pharmacology ; Hepatocyte Growth Factor -- Metabolism ; Neoplasms -- Metabolism ; Proto-Oncogene Proteins C-Met -- Antagonists & Inhibitors
    ISSN: 1078-0432
    E-ISSN: 15573265
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  • 8
    In: Anti-Cancer Drugs, 2011, Vol.22(3), pp.245-252
    Description: Sphingosine kinase 1 (Sphk1), a lipid kinase implicated in cell transformation and tumor growth, is overexpressed in gastric cancer and is linked with a poor prognosis. The biological relevance of Sphk1 expression in gastric cancer is unclear. Here, we studied the functional significance of Sphk1 as a novel molecular target for gastric cancer by using an antisense oligonucleotide approach in vitro and in vivo.Gastric cancer cell lines (MKN28 and N87) were treated with Sphk1 with locked nucleic acid–antisense oligonucleotides (LNA–ASO). Sphk1 target regulation, cell growth, and apoptosis were assessed for single-agent Sphk1 LNA–ASO and for combinations with doxorubicin. Athymic nude mice xenografted with gastric cancer cells were treated with Sphk1 LNA and assessed for tumor growth and Sphk1 target regulation, in vivo.In vitro, nanomolar concentrations of Sphk1 LNA–ASO induced an approximately two-fold reduction in Sphk1 mRNA in both the cell lines. This resulted in a 1.6-fold increase in apoptosis and inhibited the growth of gastric cancer cells by more than 50% (P〈0.05). The combination of Sphk1 LNA–ASO with doxorubicin resulted in significant chemosensitization. In vivo, Sphk1 LNA–ASO displayed neither mRNA target regulation in xenografts nor antitumor activity in two independent nude mouse xenograft models.In conclusion, the potent single-agent activity and the synergistic effect of Sphk1 LNA–ASO in combination with chemotherapy in vitro highlight Sphk1 as a biologically relevant molecular target for gastric cancer. Further studies are warranted to overcome the challenge of delivering Sphk1-targeting RNA-therapeutics to solid tumors in vivo.
    Keywords: Molecular Targeted Therapy ; Apoptosis -- Drug Effects ; Cell Proliferation -- Drug Effects ; Oligonucleotides, Antisense -- Pharmacology ; Phosphotransferases (Alcohol Group Acceptor) -- Genetics ; Stomach Neoplasms -- Drug Therapy;
    ISSN: 0959-4973
    E-ISSN: 14735741
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  • 9
    Language: English
    In: Cancer Biology & Therapy, 01 June 2010, Vol.9(11), pp.919-927
    Description: The vascular endothelial growth factor (VEGF) is a central mediator of tumor-induced angiogenesis. Everolimus, a mammalian target of rapamycin (mTOR) inhibitor, decreases VEGF-secretion of cancer cells. Vatalanib is a selective inhibitor of...
    Keywords: Medicine
    ISSN: 1538-4047
    E-ISSN: 1555-8576
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  • 10
    Language: English
    In: Cancer Letters, 2010, Vol.296(2), pp.249-256
    Description: VEGF receptor blockage has been reported to increase serum VEGF. We hypothesized that mTOR inhibition by everolimus counteracts VEGF induction by sunitinib resulting in an improved anti-tumor activity of sunitinib. , sunitinib in combination with everolimus did not outperform the respective monotherapies. monotherapies reduced tumor growth by 60%, whereas the combination of sunitinib and everolimus led to an almost complete tumor growth inhibition. This superior anti-tumor activity coincided with attenuation of VEGF peaks. In conclusion mTOR inhibition by everolimus counteracts VEGF induction by sunitinib and results in significant reduction of tumor burden and long-lasting tumor growth control.
    Keywords: Angiogenesis ; Gastric Cancer ; Mtor ; Sunitinib ; Vegf ; Medicine
    ISSN: 0304-3835
    E-ISSN: 1872-7980
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