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)

The chromosomal translocation t(2;5)(p23;q35) is associated with "Anaplastic large cell lymphomas" (ALCL), a Non Hodgkin Lymphoma occurring in childhood. The fusion of the tyrosine kinase gene-ALK (anaplastic lymphoma kinase) on chromosome 2p23 to the NPM (nucleophosmin/B23) gene on chromosome 5q35 results in a 80 kDa chimeric protein, which activates the "survival" kinase PI3K. However, the binding mechanism between truncated ALK and PI3K is poorly understood. Therefore, we attempted to elucidate the molecular interaction between ALK and the regulatory p85 subunit of PI3K. Here we provide evidence that the truncated ALK homodimer binds to the SH3 domain of p85. This finding may be useful for the development of a new target-specific intervention.
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PMID:Truncated ALK derived from chromosomal translocation t(2;5)(p23;q35) binds to the SH3 domain of p85-PI3K. 1568 Mar 99

Approximately one third of acute myeloid leukemias (AMLs) are characterized by aberrant cytoplasmic localization of nucleophosmin (NPMc+ AML), consequent to mutations in the NPM putative nucleolar localization signal. These events are mutually exclusive with the major AML-associated chromosomal rearrangements, and are frequently associated with normal karyotype, FLT3 mutations, and multilineage involvement. We report the gene expression profiles of 78 de novo AMLs (72 with normal karyotype; 6 without major chromosomal abnormalities) that were characterized for the subcellular localization and mutation status of NPM. Unsupervised clustering clearly separated NPMc+ from NPMc- AMLs, regardless of the presence of FLT3 mutations or non-major chromosomal rearrangements, supporting the concept that NPMc+ AML represents a distinct entity. The molecular signature of NPMc+ AML includes up-regulation of several genes putatively involved in the maintenance of a stem-cell phenotype, suggesting that NPMc+ AML may derive from a multipotent hematopoietic progenitor.
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PMID:Acute myeloid leukemia bearing cytoplasmic nucleophosmin (NPMc+ AML) shows a distinct gene expression profile characterized by up-regulation of genes involved in stem-cell maintenance. 1583 97

More than half of anaplastic large-cell lymphoma (ALCL) are associated with chromosomal translocation t(2;5)(p23;q35) that leads to the expression of nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) oncoprotein. NPM-ALK activates the antiapoptotic phosphatidylinositol-3 kinase/Akt (PI3K/Akt) signaling pathway, which plays a critical role in cell survival and apoptosis. Inhibition of the PI3K/Akt pathway has been considered as a therapeutic target for cancer where PI3K/Akt activation is a causative factor. Genistein, a natural isoflavonoid found in soy products, has been shown to inhibit cell growth and induce apoptosis in a wide variety of cell lines. Here, we demonstrated that treatment of two t(2;5) ALCL cell lines, SUDHL-1 and Karpas299, with genistein induced apoptosis in a time- and dose-dependent manner. Concurrently, these cells exhibited a decrease in Akt protein levels and subsequent downregulation of Akt activity (Akt phosphorylation). Furthermore, genistein treatment induced mitochondrial membrane potential change, caspase-3 activation and PARP cleavage. From these results, we conclude that inhibition of the Akt signaling pathway and induction of apoptosis by genistein could be used as a new treatment modality for the prevention and/or treatment of t(2;5) ALCL and other hematopoietic malignancies.
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PMID:Genistein-induced apoptosis via Akt signaling pathway in anaplastic large-cell lymphoma. 1588 21

The nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) is generated as a t(2;5) chromosomal breakpoint product, typically in CD30(+) anaplastic large cell lymphomas. Activation of the NPM-ALK tyrosine kinase by NPM dimerisation causes autophosphorylation at multiple tyrosine residues and the consequent recruitment of a 'signalosome' that couples the fusion protein to pathways regulating mitogenesis and apoptosis. This review focuses on recent advances in our understanding of the transforming signals induced by this fusion protein in mouse models.
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PMID:What have we learnt from mouse models of NPM-ALK-induced lymphomagenesis? 1590 87

The anaplastic lymphoma kinase (ALK), whose constitutively active fusion proteins are responsible for 5-10% of non-Hodgkin's lymphomas, shares with the other members of the insulin receptor kinase (IRK) subfamily an activation loop (A-loop) with the triple tyrosine motif Y-x-x-x-Y-Y. However, the amino acid sequence of the ALK A-loop differs significantly from the sequences of both the IRK A-loop and the consensus A-loop for this kinase subfamily. A major difference is the presence of a unique "RAS" triplet between the first and second tyrosines of the ALK A-loop, which in IRK is replaced by "ETD". Here we show that a peptide reproducing the A-loop of ALK is readily phosphorylated by ALK, while a homologous IRK A-loop peptide is not unless its "ETD" triplet is substituted by "RAS". Phosphorylation occurs almost exclusively at the first tyrosine of the Y-x-x-x-Y-Y motif, as judged by Edman analysis of the phosphoradiolabeled product. Consequently, a peptide in which the first tyrosine had been replaced by phenylalanine (FYY) was almost unaffected by ALK. In contrast, a peptide in which the second and third tyrosines had been replaced by phenylalanine (YFF) was phosphorylated more rapidly than the parent peptide (YYY). A number of substitutions in the YFF peptide outlined the importance of Ile and Arg at positions n - 1 and n + 6 in addition to the central triplet, to ensure efficient phosphorylation by ALK. Such a peculiar substrate specificity allows the specific monitoring of ALK activity in crude extracts of NPM-ALK positive cells, using the YFF peptide, which is only marginally phosphorylated by a number of other tyrosine kinases.
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PMID:Unique substrate specificity of anaplastic lymphoma kinase (ALK): development of phosphoacceptor peptides for the assay of ALK activity. 1593 44

Nucleophosmin (NPM)/B23, a multifunctional nucleolar protein, is overexpressed in actively proliferating cells and cancer cells. B23 is a tumor marker and exerts its oncogenic effect through binding and suppressing numerous tumor suppressors. NPM-ALK, an aberrant fusion protein produced from t(2;5) translocation in anaplastic large cell lymphoma (ALCL), fuses the N-terminus of B23 to the intracellular tyrosine kinase domain of ALK, provoking lymphomas by stimulating various mitogenic proteins including PI 3-kinase and PLC-gamma1. Overexpression of B23 inhibits apoptosis, while knockdown of B23 induces cell death. However, whether B23 is directly involved in blocking apoptotic machinery remains elusive. B23 is recently identified as a nuclear PI(3,4,5)P3 binding protein through a PI(3,4,5)P3 column and NGF-treated PC12 nuclear extracts. B23 has been shown to mediate the anti-apoptotic effects of NGF by inhibiting DNA fragmentation activity of CAD. B23 mutants that cannot associate with PI(3,4,5)P3 fail to prevent DNA fragmentation, indicating that PI(3,4,5)P3/B23 complex regulates the anti-apoptotic activity of NGF in the nucleus. Identification of a small molecule mediating the anti-apoptotic action of B23 unveils a novel therapeutic target for treatment of B23 amplified cancers.
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PMID:Nucleophosmin/B23, a multifunctional protein that can regulate apoptosis. 1610 50

Genetic and molecular techniques have provided increasing insights into the biology of acute myeloid leukemia (AML). These investigations showed that AML is not a homogeneous disease but a heterogeneous group of biologically different subentities. These subentities are currently primarily defined by cytogenetics by which three main subgroups can be discriminated: AML with balanced translocations, AML with unbalanced aberrations and AML without cytogenetically detectable aberrations. Within the latter group molecular alterations are identified in more than half of cases such as NPM mutations, FLT3 mutations, MLL duplications and mutations of CEBP-alpha. The clinical meaning of these findings is illustrated by substantial differences in response to therapy and long-term outcome. As demonstrated by the recent multicenter trial of the German AML Cooperative Group (AMLCG) and other studies intensification of induction therapy may improve the results in distinct subtypes but fails to do so in others. Therefore, new strategies need to be explored which incorporate the knowledge about the biology of AML to develop biology adapted treatment strategies. This process has just begun and is predominantly determined by the availability of new agents and their evaluation in clinical phase I and II studies. A variety of targets are currently explored and some trials have yielded promising results already. The step towards a biology adapted treatment of AML is long and requires the combined efforts of researchers, clinicians and the pharmaceutical industry. The first steps towards this goal have been taken and give rise to the hope for more effective and more specific therapies of AML.
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PMID:Towards a pathogenesis-oriented therapy of acute myeloid leukemia. 1620 31

The roles of aberrant expression of constitutively active ALK chimeric proteins in the pathogenesis of anaplastic large-cell lymphoma (ALCL) have been well defined; nevertheless, the notion that ALK is a molecular target for the therapeutic modulation of ALK+ ALCL has not been validated thus far. Select fused pyrrolocarbazole (FP)-derived small molecules with ALK inhibitory activity were used as pharmacologic tools to evaluate whether functional ALK is essential for the proliferation and survival of ALK+ ALCL cells in culture. These compounds inhibited interleukin 3 (IL-3)-independent proliferation of BaF3/NPM-ALK cells in an ALK inhibition-dependent manner and significantly blocked colony formation in agar of mouse embryonic fibroblast (MEF) cells harboring NPM-ALK. Inhibition of NPM-ALK phosphorylation in the ALK+ ALCL-derived cell lines resulted in significant inhibition of cell proliferation and induction of apoptotic-cell death, while having marginal effects on the proliferation and survival of K562, an ALK- leukemia cell line. ALK inhibition resulted in cell-cycle G1 arrest and inactivation of ERK1/2, STAT3, and AKT signaling pathways. Potent and selective ALK inhibitors may have therapeutic application for ALK+ ALCL and possibly other solid and hematologic tumors in which ALK activation is implicated in their pathogenesis.
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PMID:Anaplastic lymphoma kinase activity is essential for the proliferation and survival of anaplastic large-cell lymphoma cells. 1625 37

Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase essentially and transiently expressed in specific areas of the developing central and peripheral nervous systems. We previously demonstrated that a membrane-bound and constitutively active form of the ALK protein tyrosine kinase (PTK) domain induced the neuron-like differentiation of PC12 cells through specific activation of the mitogen-activated protein kinase (MAP kinase) pathway. Its PTK domain had been originally identified in a nucleo-cytosolic and constitutively active transforming protein, NPM-ALK. Downstream targets involved in oncogenic proliferation and survival processes have been proposed to include phospholipase Cgamma (PLCgamma), phosphoinositide 3-kinase (PI 3-kinase)/AKT, STAT 3/5 and Src. We therefore postulated that activation of specific signaling pathways leading to differentiation or proliferation can be differently controlled depending on the subcellular localization of ALK PTK domain. To increase knowledge of its physiological role in the nervous system, we focused in the present study on the influence of its subcellular localization on neuronal differentiation. To achieve this goal, we characterized biological responses and transduction pathways in PC12 cells elicited by various constructs encoding membrane-bound (through transmembrane or myristyl sequences) or cytosolic ALK-derived proteins. In order to control the activation of their PTK domain, we used an inducible dimerization system. Here, we demonstrate that membrane attachment of the ALK PTK domain, in PC12 cells, is crucial for initiation of neurite outgrowth and proliferation arrest through a decrease of DNA synthesis. Furthermore, we show that this differentiation process relies on specific and sustained activation of ERK 1/2 proteins. By contrast, activation of the cytosolic form of this domain fails to induce MAP kinase activation and cell differentiation but promotes a PI 3-kinase/AKT-dependent PC12 cell proliferation. These data indicate that subcellular localization of the ALK PTK domain was a determinant for the control and specificity of downstream transduction cascades and was crucial for deciding the fate to which the neuronal cell will be committed.
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PMID:Role of the subcellular localization of ALK tyrosine kinase domain in neuronal differentiation of PC12 cells. 1631 43

We analyzed 2502 patients with acute myeloid leukemia at diagnosis for NRAS mutations around the hot spots at codons 12, 13, and 61 and correlated the results to cytomorphology, cytogenetics, other molecular markers, and prognostic relevance of these mutations. Two hundred fifty-seven (10.3%) of 2502 patients had NRAS mutations (NRAS(mut)). Most mutations (112 of 257; 43.6%) were found at codon 12, mostly resulting in changes from glycine to asparagine. The history of AML did not differ significantly in association with NRAS mutations. The subgroups with inv(16)/t(16;16) and inv(3)/t(3;3) showed a significantly higher frequency of NRAS(mut) (50 of 133, 37.6% [P < .001], and 11 of 41, 26.8% [P = .004], respectively) than the total cohort. In addition, in these 2 subgroups, mutations of codon 61 were significantly overrepresented (both P < .001). In contrast, NRAS mutations were significantly underrepresented in t(15;17) (2 of 102; 2%; P = .005) in the subgroup with MLL/11q23 rearrangements (3 of 77; 3.9%; P = .061) and in the complex aberrant karyotype (4 of 258; 1.6%; P < .001). Overall, we did not find a significant prognostic impact of NRAS(mut) for overall survival, event-free survival, and disease-free survival. However, there was a trend to better survival in most subgroups, especially when other molecular markers (FLT3-LM, MLL-PTD, and NPM) were taken into account.
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PMID:Implications of NRAS mutations in AML: a study of 2502 patients. 1643 92


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