Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.10.1 (ERK)
95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A newly established GM7 cell line was derived from the tumor tissue of a 65-year-old man surgically treated for a relapse of glioblastoma multiforme that occurred 10 months after first surgery following radiotherapy. GM7 cells exhibit spindle or glia-like morphology, and multinucleated giant cells are also present in the culture. The cells proliferate rapidly (PDT is about 18 h) and tend to grow in multilayer without contact inhibition. Using G-banding and SKY, the GM7 cell line was identified as near-triploid with a large number of structural and numerical abnormalities. Repeated karyotyping during long-term cultivation confirmed a chromosome number of 70+/-3 chromosomes per cell. Special attention was paid to the immunocytochemical analysis of protein markers in this cell line; GM7 cells showed strong positivity for CD133, vimentin, nestin, NF-160 and S-100 protein and weak positivity for GFAP and NSE, but were negative for synaptophysin. The most important features of the GM7 cell line are its stable phenotype CD133+/nestin+, which are accepted as stem cell markers in neural stem/progenitor cells, and especially unusual intracellular localization of the IF protein nestin, which was detected and repeatedly confirmed both in the cytoplasm and cell nucleus. For this reason, the new GM7 glioblastoma cell line represents an important model suitable not only for further studies on glioblastoma biology and cancer stem cells, but particularly for the detailed investigation of the role of nestin in transformed cells.
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PMID:Characterization of a GM7 glioblastoma cell line showing CD133 positivity and both cytoplasmic and nuclear localization of nestin. 1908 52

RAF proteins are well known oncoproteins. The B-RAF has been shown to be activated by mutations in a multitude of human cancers. Alterations of C-RAF expression are discussed to play a role in lung cancer. Only for A-RAF no link to tumorigenesis has been published so far. Malignant gliomas are the most prevalent primary brain tumors of adults. They are highly invasive and very difficult to treat, despite of surgery, gamma-irradiation and chemotherapy. Although a role of the mitogenic Ras-RAF-MEK-ERK signalling cascade in brain tumor development is well established, there are only few reports available addressing alterations in RAF sequence or protein expression and function in human gliomas. We analysed the mutational status of A-RAF and B-RAF in human glioblastomas (GBM) by sequencing. Then we checked for RAF gene amplification by dot blot hybridization and examined RAF mRNA and protein expression patterns in human astrocytic gliomas of WHO grade II (LGA) and IV (GBM) by semiquantitative RT-PCR and Western blotting, respectively. The results were correlated with patients prognosis. Finally, we performed functional assays to address a putative function of A-RAF in glioma cell proliferation and migration. We showed that RAF mutations are a rare event in glioblastoma multiforme. A-raf gene amplification was more often detected and overexpression of all three RAF proteins on mRNA and protein level was regularly found in human malignant gliomas. Whereas A-RAF and C-RAF expression was negatively correlated with the patients prognosis, B-RAF expression had a positive effect. Since neither A-RAF, nor C-RAF expression had any influence on proliferation and migration of GBM cells, putative functions of C-RAF in angiogenesis and of A-RAF in regulation of metabolism are discussed. Our data indicate that RAF proteins might be valuable targets for small molecule therapies. However, initially specific functions of RAF during tumorigenesis have to be elucidated.
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PMID:RAF expression in human astrocytic tumors. 1908 3

Development of model systems that recapitulate the molecular heterogeneity observed among glioblastoma multiforme (GBM) tumors will expedite the testing of targeted molecular therapeutic strategies for GBM treatment. In this study, we profiled DNA copy number and mRNA expression in 21 independent GBM tumor lines maintained as subcutaneous xenografts (GBMX), and compared GBMX molecular signatures to those observed in GBM clinical specimens derived from the Cancer Genome Atlas (TCGA). The predominant copy number signature in both tumor groups was defined by chromosome-7 gain/chromosome-10 loss, a poor-prognosis genetic signature. We also observed, at frequencies similar to that detected in TCGA GBM tumors, genomic amplification and overexpression of known GBM oncogenes, such as EGFR, MDM2, CDK6, and MYCN, and novel genes, including NUP107, SLC35E3, MMP1, MMP13, and DDX1. The transcriptional signature of GBMX tumors, which was stable over multiple subcutaneous passages, was defined by overexpression of genes involved in M phase, DNA replication, and chromosome organization (MRC) and was highly similar to the poor-prognosis mitosis and cell-cycle module (MCM) in GBM. Assessment of gene expression in TCGA-derived GBMs revealed overexpression of MRC cancer genes AURKB, BIRC5, CCNB1, CCNB2, CDC2, CDK2, and FOXM1, which form a transcriptional network important for G2/M progression and/or checkpoint activation. Our study supports propagation of GBM tumors as subcutaneous xenografts as a useful approach for sustaining key molecular characteristics of patient tumors, and highlights therapeutic opportunities conferred by this GBMX tumor panel for testing targeted therapeutic strategies for GBM treatment.
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PMID:Comparative analyses of gene copy number and mRNA expression in glioblastoma multiforme tumors and xenografts. 1913 20

Primary glioblastoma multiforme (GBM), in contrast with secondary GBM, has been associated with the presence of EGFR amplification and absence of p53 mutation. In this study, we analyzed relevant molecular and clinical variables in 194 primary GBMs and tested them for survival analysis. Although most of the tumors showed a mutually exclusive pattern, concurrent alterations of EGFR and p53 were detected. Survival analysis of CDK4 amplification revealed a highly significant association with a worse clinical outcome (P = .01), whereas MDM2, CDK6, PTEN, and p21 were not associated with patient survival. Multivariate analysis including the significant clinical and molecular variables revealed CDK4 amplification, age, and radiotherapy to be markers with independent prognostic value. In addition, the primary GBM tumors showing simultaneous EGFR and p53 alterations were significantly associated with worse survival (P < .01). These results highlight the prognostic value of CDK4 amplification and of simultaneous EGFR-p53 alterations in the clinical outcome of patients with primary GBM.
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PMID:Worse outcome in primary glioblastoma multiforme with concurrent epidermal growth factor receptor and p53 alteration. 1914 86

Apoptosis or programmed cell-death is an important process involved in tissue homeostasis, development and a variety of immune responses.(1) The apoptotic program can be activated via transmembrane receptors stimulated by their cognate ligands. The presence of a well-conserved region of 80 amino acids in their intracellular tail, the Death-Domain (DD), has conferred those receptors the general name of "death receptors". Death receptors are a subfamily of the TNF receptor superfamily, which includes the TNF receptor-I (TNFR1), TRAMP, DR3/APO-3, TRAIL-receptor 1 (TRAIL-R1/DR4), TRAIL-receptor 2 (TRAIL-R1/DR5), DR6 and CD95 (Fas/Apo-1). The pro-apoptotic properties of the CD95 system have been extensively studied during the past decades. Nevertheless, CD95 has now emerged as an important activator of other major signaling pathways leading to a variety of phenotypes. In the last years, stimulation of CD95 has been described to activate the MAPK pathways p38, JNK and ERK. (2-6) CD95 has also been shown to activate the transcription factor NFkB. (67-9) However, the molecular mechanisms leading to activation of such pathways are not fully understood and their contribution to the final phenotype is still unclear. CD95 has been shown to be particularly involved in tumor cell invasion, (6) neurite sprouting and outgrowth,(5,10) as well as cell proliferation(11,12)--functions that lay to rest the general assumption of CD95 as a death receptor. In our group we have recently described a novel molecular link between CD95 and the phosphatydilinositol-3-kinase (PI3K) pathway in Glioblastoma multiforme. In the present review we will discuss the past and present knowledge of the CD95/CD95L system and its role in PI3K signaling.
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PMID:Tyrosine phosphorylation and CD95: a FAScinating switch. 1922 5

Glioblastoma multiforme (GBM) represents an extremely chemoresistant tumour type. Here, authors analysed the immunophenotype of GBM tumours by flow cytometry and correlated the immunophenotypic characteristics with sensitivity to chemotherapy. The expression of selected neural and non-neural differentiation markers including A2B5, CD34, CD45, CD56, CD117, CD133, EGFR, GFAP, Her-2/neu, LIFR, nestin, NGFR, Pgp and vimentin was analysed by flow cytometry in eleven GBM (WHO gr.IV) patients. The sensitivity of tumour cells to a panel of chemotherapeutic agents was tested by the MTT assay. All tumours were positive for A2B5, CD56, nestin and vimentin. CD133, EGFR, LIFR, NGFR and Pgp were expressed only by minor tumour cell subpopulations. CD34, CD45, CD117, GFAP and Her-2/neu were constantly negative. Direct correlations were found between the immunophenotypic markers and chemosensitivity: A2B5 vs lomustine (r(2) = 0.642, P = 0.033), CD56 vs cisplatin (r(2) = 0.745, P = 0.013), %Pgp(+) vs vincristine (r(2) = 0.846, P = 0.008), and %NGFR(+) vs daunorubicine (r(2) = 0.672, P = 0.047) and topotecan (r(2) = 0.792, P = 0.011). In contrast, inverse correlations were observed between: EGFR vs paclitaxel (r(2) = -0.676, P = 0.046), CD133 vs dacarbazine (r(2) = -0.636, P = 0.048) and LIFR vs daunorubicine (r(2) = -0.878, P = 0.004). Finally, significant associations were also found among sensitivities to different chemotherapeutic agents and among different immunophenotypic markers. In conclusion, histopathologically identical GBM tumours displayed a marked immunophenotypic heterogeneity. The expression of A2B5, CD56, NGFR and Pgp appeared to be associated with chemoresistance whereas CD133, EGFR and LIFR expression was characteristic of chemosensitive tumours. We suggest that flow cytometric imunophenotypic analysis of GBM may predict chemoresponsiveness and help to identify patients who could potentially benefit from chemotherapy.
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PMID:Flow cytometry analysis of neural differentiation markers expression in human glioblastomas may predict their response to chemotherapy. 1928 88

Despite surgical advances and recent progress in adjuvant therapies, the prognosis for patients with malignant brain tumors such as glioblastoma multiforme has remained poor, and the neurological deterioration suffered by most patients as a consequence of tumor progression is dramatic and severe. In addition, malignant brain tumors have >>95% recurrence close to the primary site of initial resection. Unfortunately, standard imaging techniques do not permit the intraoperative identification of individual or small clusters of residual tumor cells, precluding their selective removal while sparing the surrounding normal brain tissue. In this report, we show that quantum dots (QDs) coupled to epidermal growth factor (EGF) or anti-EGF receptor receptor (EGFR, Her1) specifically and sensitively label glial tumor cells in cell culture, glioma mouse models, and human brain-tumor biopsies. A clear demarcation between brain and tumor tissue at the macroscopic as well as the cellular level is provided by the fluorescence emission of the QDs.
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PMID:Tumor-targeted quantum dots can help surgeons find tumor boundaries. 1930 3

Not all Glioblastoma multiforme (GBM, grade IV WHO) manifest the same clinical course. Different prognostic classes may arise from different morphologic and genetic profiles. The observation of oligodendroglial foci within GBM samples and their correlation with genetic alterations may predict a better prognosis. 450 patients affected by histologically proven supratentorial cerebral GBM were treated at our institutions from January 2000 to December 2006: all patients received at least subtotal surgical removal, followed by the same standard radio-chemotherapy adjuvant treatment. In a subgroup of 36 patients (8.0%) an oligodendroglial component was observed. Molecular assessment of these cases was performed and LOH for 1p, 19q and 10q, EGFR amplification and TP53 gene expression was determined. Median age of this subgroup was 52.1 years (range: 29-78 years) vs 62.4 years in the entire GBM population. Chromosome analysis resulted as follows: LOH 1p and/or 19q in 27 cases (75.0%), LOH of 10q in 21 cases (58.1%), EGFR amplification in 14 cases (39%) and TP53 mutation in eight patients (22.2%). OS was of 20.9 months while it was 13.6 months in the entire GBM population. Progression free survival (PFS) was 10.3 months and 7.6 months the entire group. Two-year survival was of 55%. The presence of an oligodendroglial component in GBM appears to be an important prognostic factor to which better prognosis can be related. LOH 1p and 19q was significantly associated with GBM with oligodendroglial component.
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PMID:Cerebral glioblastoma with oligodendrogliomal component: analysis of 36 cases. 2122 90

Glioblastoma multiforme (GBM) is the most lethal of brain tumors and is highly resistant to ionizing radiation (IR) and chemotherapy. Here, we report on a molecular mechanism by which a key glioma-specific mutation, epidermal growth factor receptor variant III (EGFRvIII), confers radiation resistance. Using Ink4a/Arf-deficient primary mouse astrocytes, primary astrocytes immortalized by p53/Rb suppression, as well as human U87 glioma cells, we show that EGFRvIII expression enhances clonogenic survival following IR. This enhanced radioresistance is due to accelerated repair of DNA double-strand breaks (DSB), the most lethal lesion inflicted by IR. The EGFR inhibitor gefitinib (Iressa) and the phosphatidylinositol 3-kinase (PI3K) inhibitor LY294002 attenuate the rate of DSB repair. Importantly, expression of constitutively active, myristylated Akt-1 accelerates repair, implicating the PI3K/Akt-1 pathway in radioresistance. Most notably, EGFRvIII-expressing U87 glioma cells show elevated activation of a key DSB repair enzyme, DNA-dependent protein kinase catalytic subunit (DNA-PKcs). Enhanced radioresistance is abrogated by the DNA-PKcs-specific inhibitor NU7026, and EGFRvIII fails to confer radioresistance in DNA-PKcs-deficient cells. In vivo, orthotopic U87-EGFRvIII-derived tumors display faster rates of DSB repair following whole-brain radiotherapy compared with U87-derived tumors. Consequently, EGFRvIII-expressing tumors are radioresistant and continue to grow following whole-brain radiotherapy with little effect on overall survival. These in vitro and in vivo data support our hypothesis that EGFRvIII expression promotes DNA-PKcs activation and DSB repair, perhaps as a consequence of hyperactivated PI3K/Akt-1 signaling. Taken together, our results raise the possibility that EGFR and/or DNA-PKcs inhibition concurrent with radiation may be an effective therapeutic strategy for radiosensitizing high-grade gliomas.
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PMID:EGFRvIII and DNA double-strand break repair: a molecular mechanism for radioresistance in glioblastoma. 1943 98

Tumorigenesis in human glioblastoma multiforme (GBM) is driven by several genetic abnormalities with disruption of important molecular pathways, such as p53/MDM2/p14ARF and EGFR/PTEN/Akt/mTOR. The malignant progression of human GBM is also primarily associated with a peculiar multistep pathophysiological process characterized by intratumoral ischemic necrosis (i.e. pseudopalisading necrosis) and activation of the hypoxia-inducible factor (HIF)-1alpha pathway with consequent peritumoral microvascular proliferation and infiltrative behaviour. Predictable preclinical animal models of GBM should recapitulate the main pathobiological hallmarks of the human disease. In this study we describe two murine orthotopic xenograft models using U87MG and U251 human cell lines. Ten Balb/c nude male mice were orthotopically implanted with either U87MG (5 mice) or U251 (5 mice) cell lines. Intracranial tumor growth was monitored through Magnetic Resonance Imaging (MRI). Immunohistopathological examination of the whole cranium was performed 30 days after implantation. U251 orthotopic xenografts recapitulated the salient pathobiological features described for human GBM, including invasive behaviour, wide areas of pseudopalisading necrosis, florid peripheral angiogenesis, GFAP and vimentin expression, nonfunctional p53 expression, striking active-caspase-3 and HIF-1alpha expression along pseudopalisades. U87MG orthotopic xenografts proved to be very dissimilar from human GBM, showing expansile growth, occasional necrotic foci without pseudopalisades, intratumoral lacunar pattern of angiogenesis, lack of GFAP expression, functional p53 expression and inconsistent HIF-1alpha expression. Expression of pAkt was upregulated in both models. The results obtained suggest that the U251 orthotopic model may be proposed as a predictive and reliable tool in preclinical studies since it recapitulates the most salient pathobiological features reported for human GBM.
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PMID:Immunohistopathological and neuroimaging characterization of murine orthotopic xenograft models of glioblastoma multiforme recapitulating the most salient features of human disease. 1947 34


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