Kooperativer Bibliotheksverbund

Berlin Brandenburg

and
and

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
Type of Medium
Language
Year
  • 1
    Language: English
    In: Proceedings of the National Academy of Sciences of the United States of America, 07 January 2014, Vol.111(1), pp.409-14
    Description: A hypoxic microenvironment induces resistance to alkylating agents by activating targets in the mammalian target of rapamycin (mTOR) pathway. The molecular mechanisms involved in this mTOR-mediated hypoxia-induced chemoresistance, however, are unclear. Here we identify the mTOR target N-myc downstream regulated gene 1 (NDRG1) as a key determinant of resistance toward alkylating chemotherapy, driven by hypoxia but also by therapeutic measures such as irradiation, corticosteroids, and chronic exposure to alkylating agents via distinct molecular routes involving hypoxia-inducible factor (HIF)-1alpha, p53, and the mTOR complex 2 (mTORC2)/serum glucocorticoid-induced protein kinase 1 (SGK1) pathway. Resistance toward alkylating chemotherapy but not radiotherapy was dependent on NDRG1 expression and activity. In posttreatment tumor tissue of patients with malignant gliomas, NDRG1 was induced and predictive of poor response to alkylating chemotherapy. On a molecular level, NDRG1 bound and stabilized methyltransferases, chiefly O(6)-methylguanine-DNA methyltransferase (MGMT), a key enzyme for resistance to alkylating agents in glioblastoma patients. In patients with glioblastoma, MGMT promoter methylation in tumor tissue was not more predictive for response to alkylating chemotherapy in patients who received concomitant corticosteroids.
    Keywords: Drug Resistance, Neoplasm ; Gene Expression Regulation, Neoplastic ; Antineoplastic Agents, Alkylating -- Pharmacology ; Brain Neoplasms -- Drug Therapy ; Cell Cycle Proteins -- Metabolism ; Glioblastoma -- Drug Therapy ; Glioma -- Drug Therapy ; Intracellular Signaling Peptides and Proteins -- Metabolism ; O(6)-Methylguanine-DNA Methyltransferase -- Pharmacology ; Tor Serine-Threonine Kinases -- Metabolism
    ISSN: 00278424
    E-ISSN: 1091-6490
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    In: Journal of Neurochemistry, October 2014, Vol.131(2), pp.251-264
    Description: Human glioblastomas may be hierarchically organized. Within this hierarchy, glioblastoma‐initiating cells have been proposed to be more resistant to radiochemotherapy and responsible for recurrence. Here, established stem cell markers and stem cell attributed characteristics such as self‐renewal capacity and tumorigenicity have been profiled in primary glioblastoma cultures to predict radiosensitivity. Furthermore, the sensitivity to radiotherapy of different subpopulations within a single primary glioblastoma culture was analyzed by a flow cytometric approach using Nestin, SRY (sex‐determining region Y)‐box 2 (SOX2) and glial fibrillary acidic protein. The protein expression of Nestin and SOX2 as well as the mRNA levels of Musashi1, L1 cell adhesion molecule, CD133, Nestin, and pleiomorphic adenoma gene‐like 2 inversely correlated with radioresistance in regard to the clonogenic potential. Only CD44 protein expression correlated positively with radioresistance. In terms of proliferation, Nestin protein expression and Musashi1, pleiomorphic adenoma gene‐like 2, and CD133 mRNA levels are inversely correlated with radioresistance. Higher expression of stem cell markers does not correlate with resistance to radiochemotherapy in the cancer genome atlas glioblastoma collective. SOX2 expressing subpopulations exist within single primary glioblastoma cultures. These subpopulations predominantly form the proliferative pool of the primary cultures and are sensitive to irradiation. Thus, profiling of established stem cell markers revealed a surprising result. Except CD44, the tested stem cell markers showed an inverse correlation between expression and radioresistance. Markers used to define glioma‐initiating cells (GIC) are generally not defining a more resistant, but rather a more sensitive group of glioma cells. An exemption is CD44 expression. Also proliferation of the GIC culture itself was not systematically associated with radiosensitivity or – resistance, but a SOX‐2 positive, proliferative subgroup within a GIC culture is showing the highest radiosensitivity. Markers used to define glioma‐initiating cells (GIC) are generally not defining a more resistant, but rather a more sensitive group of glioma cells. An exemption is CD44 expression. Also proliferation of the GIC culture itself was not systematically associated with radiosensitivity or – resistance, but a SOX‐2 positive, proliferative subgroup within a GIC culture is showing the highest radiosensitivity.
    Keywords: Cd133 ; Glioma‐Initiating Cells ; Profiling ; Radiotherapy Sensitivity ; Sox2 ; Stem Cell Markers
    ISSN: 0022-3042
    E-ISSN: 1471-4159
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    Language: English
    In: Nature, 03 December 2015, Vol.528(7580), pp.93-8
    Description: Astrocytic brain tumours, including glioblastomas, are incurable neoplasms characterized by diffusely infiltrative growth. Here we show that many tumour cells in astrocytomas extend ultra-long membrane protrusions, and use these distinct tumour microtubes as routes for brain invasion, proliferation, and to interconnect over long distances. The resulting network allows multicellular communication through microtube-associated gap junctions. When damage to the network occurred, tumour microtubes were used for repair. Moreover, the microtube-connected astrocytoma cells, but not those remaining unconnected throughout tumour progression, were protected from cell death inflicted by radiotherapy. The neuronal growth-associated protein 43 was important for microtube formation and function, and drove microtube-dependent tumour cell invasion, proliferation, interconnection, and radioresistance. Oligodendroglial brain tumours were deficient in this mechanism. In summary, astrocytomas can develop functional multicellular network structures. Disconnection of astrocytoma cells by targeting their tumour microtubes emerges as a new principle to reduce the treatment resistance of this disease.
    Keywords: Astrocytoma -- Pathology ; Brain Neoplasms -- Pathology ; Gap Junctions -- Metabolism
    ISSN: 00280836
    E-ISSN: 1476-4687
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Language: English
    In: Cancer Research, 04/15/2012, Vol.72(8 Supplement), pp.4736-4736
    ISSN: 0008-5472
    E-ISSN: 1538-7445
    Source: CrossRef
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Language: English
    In: Cancer discovery, November 2011, Vol.1(6), pp.475-6
    Description: mTOR signaling is frequently deregulated in cancer, including brain tumors. Although the signaling of mTOR complex 1 (mTORC1) has been subject to intensive investigations and mTORC1 itself has been a well-established cancer drug target for years, the role of the second complex, mTORC2, remains elusive. Tanaka et al. reveal an EGFRvIII-mTORC2-NFκB signaling cascade and demonstrate that mTORC2 mediates cisplatin resistance through NF-κB in an Akt-independent manner in glioblastoma. Uncovering the role of mTORC2 in chemotherapy resistance in glioblastoma highlights the need for further investigations of mTORC2 inhibition.
    Keywords: Brain Neoplasms -- Metabolism ; Erbb Receptors -- Metabolism ; Glioblastoma -- Metabolism ; Nf-Kappa B -- Metabolism ; Transcription Factors -- Metabolism
    ISSN: 21598274
    E-ISSN: 2159-8290
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    Language: English
    In: Clinical cancer research : an official journal of the American Association for Cancer Research, 15 December 2016, Vol.22(24), pp.6078-6087
    Description: The role of blood-brain barrier (BBB) integrity for brain tumor biology and therapy is a matter of debate. We developed a new experimental approach using in vivo two-photon imaging of mouse brain metastases originating from a melanoma cell line to investigate the growth kinetics of individual tumor cells in response to systemic delivery of two PI3K/mTOR inhibitors over time, and to study the impact of microregional vascular permeability. The two drugs are closely related but differ regarding a minor chemical modification that greatly increases brain penetration of one drug. Both inhibitors demonstrated a comparable inhibition of downstream targets and melanoma growth in vitro In vivo, increased BBB permeability to sodium fluorescein was associated with accelerated growth of individual brain metastases. Melanoma metastases with permeable microvessels responded similarly to equivalent doses of both inhibitors. In contrast, metastases with an intact BBB showed an exclusive response to the brain-penetrating inhibitor. The latter was true for macro- and micrometastases, and even single dormant melanoma cells. Nuclear morphology changes and single-cell regression patterns implied that both inhibitors, if extravasated, target not only perivascular melanoma cells but also those distant to blood vessels. Our study provides the first direct evidence that nonpermeable brain micro- and macrometastases can effectively be targeted by a drug designed to cross the BBB. Small-molecule inhibitors with these optimized properties are promising agents in preventing or treating brain metastases in patients. Clin Cancer Res; 22(24); 6078-87. ©2016 AACRSee related commentary by Steeg et al., p. 5953.
    Keywords: Blood-Brain Barrier -- Pathology ; Brain -- Pathology ; Brain Neoplasms -- Pathology ; Cell Proliferation -- Physiology
    ISSN: 1078-0432
    E-ISSN: 15573265
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Language: English
    In: The Journal of neuroscience : the official journal of the Society for Neuroscience, 19 July 2017, Vol.37(29), pp.6837-6850
    Description: Early and progressive colonization of the healthy brain is one hallmark of diffuse gliomas, including glioblastomas. We recently discovered ultralong (〉10 to hundreds of microns) membrane protrusions [tumor microtubes (TMs)] extended by glioma cells. TMs have been associated with the capacity of glioma cells to effectively invade the brain and proliferate. Moreover, TMs are also used by some tumor cells to interconnect to one large, resistant multicellular network. Here, we performed a correlative gene-expression microarray and imaging analysis, and identified novel molecular candidates for TM formation and function. Interestingly, these genes were previously linked to normal CNS development. One of the genes scoring highest in tests related to the outgrowth of TMs was (), which was highly expressed in a fraction of TMs in mice and patients. Ttyh1 was confirmed to be a potent regulator of normal TM morphology and of TM-mediated tumor-cell invasion and proliferation. Glioma cells with one or two TMs were mainly responsible for effective brain colonization, and Ttyh1 downregulation particularly affected this cellular subtype, resulting in reduced tumor progression and prolonged survival of mice. The remaining Ttyh1-deficient tumor cells, however, had more interconnecting TMs, which were associated with increased radioresistance in those small tumors. These findings imply a cellular and molecular heterogeneity in gliomas regarding formation and function of distinct TM subtypes, with multiple parallels to neuronal development, and suggest that Ttyh1 might be a promising target to specifically reduce TM-associated brain colonization by glioma cells in patients. In this report, we identify tweety-homolog 1 (Ttyh1), a membrane protein linked to neuronal development, as a potent driver of tumor microtube (TM)-mediated brain colonization by glioma cells. Targeting of Ttyh1 effectively inhibited the formation of invasive TMs and glioma growth, but increased network formation by intercellular TMs, suggesting a functional and molecular heterogeneity of the recently discovered TMs with potential implications for future TM-targeting strategies.
    Keywords: Ttyh1 ; Glioblastoma ; Glioma ; Invasion ; Migration ; Tumor Microtubes ; Brain Neoplasms -- Metabolism ; Glioblastoma -- Metabolism ; Membrane Proteins -- Metabolism
    ISSN: 02706474
    E-ISSN: 1529-2401
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Language: English
    In: Journal of Clinical Oncology, 05/20/2016, Vol.34(15_suppl), pp.11587-11587
    ISSN: 0732-183X
    E-ISSN: 1527-7755
    Source: CrossRef
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Language: English
    In: Cancer Letters, 01 October 2016, Vol.380(2), pp.568-576
    Description: Hypoxia-regulated molecules play an important role in vascular resistance to antiangiogenic treatment. N-myc downstream-regulated-gene 1 ( ) is significantly upregulated during hypoxia in glioma. It was the aim of the present study to analyze the role of on glioma angiogenesis and on antiangiogenic treatment. Orthotopically implanted glioma showed reduced tumor growth and vessel density compared to controls. RT-PCR gene array analysis revealed a 30-fold . Consequently, the supernatant from transfected U87MG glioma cells resulted in reduced HUVEC proliferation, migration and angiogenic response in tube formation assays . This effect was provoked by increased promoter activity in NDRG1 cells. Mutations in and promoter response elements suppressed promoter activity. Moreover, U87MG glioma NDRG1 knockdown supernatant contained multiple proangiogenic proteins and increased HUVEC spheroid sprouting. Sunitinib treatment of orhotopically implanted mice reduced tumor volume and vessel density in controls; in overexpressing cells no reduction of tumor volume or vessel density was observed. overexpression leads to reduced tumor growth and angiogenesis in experimental glioma upregulation of . In overexpressing glioma antiangiogenic treatment does not yield a therapeutic response.
    Keywords: Glioma Angiogenesis ; Antiangiogenic Treatment ; Resistance to Antiangiogenesis ; Glioma Microcirculation ; Tnfsf15 ; Ndrg1 ; Medicine
    ISSN: 0304-3835
    E-ISSN: 1872-7980
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    In: Glia, January 2015, Vol.63(1), pp.78-90
    Description: Tryptophan catabolism is increasingly recognized as a key and druggable molecular mechanism active in cancer, immune, and glioneural cells and involved in the modulation of antitumor immunity, autoimmunity and glioneural function. In addition to the pivotal rate limiting enzyme indoleamine‐2,3‐dioxygenase, expression of tryptophan‐2,3‐dioxygenase (TDO) has recently been described as an alternative pathway responsible for constitutive tryptophan degradation in malignant gliomas and other types of cancer. In addition, TDO has been implicated as a key regulator of neurotoxicity involved in neurodegenerative diseases and ageing. The pathways regulating TDO expression, however, are largely unknown. Here, a siRNA‐based transcription factor profiling in human glioblastoma cells revealed that the expression of human TDO is suppressed by endogenous glucocorticoid signaling. Similarly, treatment of glioblastoma cells with the synthetic glucocorticoid dexamethasone led to a reduction of TDO expression and activity and . TDO inhibition was dependent on the immunophilin FKBP52, whose FK1 domain physically interacted with the glucocorticoid receptor as demonstrated by bimolecular fluorescence complementation and proximity ligation assays. Accordingly, gene expression profile analyses revealed negative correlation of FKBP52 and TDO in glial and neural tumors and in normal brain. Knockdown of FKBP52 and treatment with the FK‐binding immunosuppressant FK506 enhanced TDO expression and activity in glioblastoma cells. In summary, we identify a novel steroid‐responsive FKBP52‐dependent pathway suppressing the expression and activity of TDO, a central and rate‐limiting enzyme in tryptophan metabolism, in human gliomas. GLIA 2015;63:78–90 This study demonstrates that TDO‐mediated tryptophan catabolism in glioblastoma cells is negatively regulated by the glucocorticoid receptor (GR) signaling. The suppression of TDO by the GR seems to be dependent on the immunophilin FKBP52 and specific for human neural cells.
    Keywords: Tryptophan ; Glucocorticoid ; Glioma ; Tumor Immune Escape ; Kynurenine
    ISSN: 0894-1491
    E-ISSN: 1098-1136
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. Further information can be found on the KOBV privacy pages