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)

While most anaplastic lymphoma kinase (ALK)-positive non-Hodgkin lymphomas (NHLs) are of T-cell lineage, a small number of B-lineage tumors with plasmablastic morphology and expression of the full-length ALK protein have been described in the literature. All of these reported tumors lacked the NPM-ALK fusion transcript. There is controversy regarding the existence of ALK fusion-positive B-cell NHL, with many investigators contending that ALK fusions are expressed uniquely in T- or null-cell lymphomas. Here we describe 2 well-characterized cases of ALK-positive B-cell lymphoma expressing the NPM-ALK fusion. Both tumors occurred in pediatric patients and showed poor response to chemotherapy. Each had plasmablastic morphology, showed immunoglobulin A restriction, and was ALK positive and CD30- by immunohistochemistry. One tumor showed the t(2;5)(p23;q35) chromosomal translocation by conventional cytogenetics. Both were positive for NPM-ALK by reverse transcriptase-polymerase chain reaction. Thus, ALK-positive plasmablastic B-cell lymphomas are more heterogeneous at the molecular level than previously recognized.
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PMID:ALK-positive plasmablastic B-cell lymphoma with expression of the NPM-ALK fusion transcript: report of 2 cases. 1281 58

A t(2;5) (p23;q35) chromosomal translocation can be found in a high percentage of anaplastic large-cell lymphomas (ALCL). This genetic abnormality leads to the expression of the NPM-ALK fusion protein, which encodes a constitutively active tyrosine kinase that plays a causative role in lymphomagenesis. Employing a modified infection/transplantation protocol utilizing an MSCV-based vector, we were able to reproducibly induce two phenotypically different lymphoma-like diseases dependent on the retroviral titers used. The first phenotype presented as a polyclonal histiocytic malignancy of myeloid/macrophage origin with a short latency period of 3-4 weeks. Clinically, the diseased mice showed rapidly progressive wasting, lymphadenopathy and pancytopenia. Mice displaying the second phenotype developed monoclonal B-lymphoid tumors with a longer latency of approximately 12-16 weeks, primarily involving the spleen and the bone marrow, with less extensive lymph node but also histologically evident extranodal organ infiltration by large immature plasmoblastic cells. The described retroviral mouse model will be useful to analyse the role of NPM-ALK in lymphomagenesis in vivo and may contribute to the development of new treatment options for NPM-ALK induced malignancies.
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PMID:The oncogenic fusion protein nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) induces two distinct malignant phenotypes in a murine retroviral transplantation model. 1287 8

Signal transducer and activator of transcription 3 (STAT3), normally activated by Janus kinase (JAK) in response to cytokine stimulation, has been shown to have oncogenic potential. In addition to JAK, recent data suggest that STAT3 can also be activated by other proteins such as the aberrant fusion protein, NPM-ALK, which is expressed in a subset of systemic anaplastic large cell lymphoma (ALCL). In this study, we investigated the possible role of JAK in activating STAT3 in ALCL using two ALK-positive ALCL cell lines, Karpas 299 and SU-DHL-1. At the steady state, JAK3 showed detectable tyrosine phosphorylation by immunoprecipitation. Treatment with AG490, a JAK inhibitor, decreased but did not completely abrogate tyrosine phosphorylation of JAK3 and STAT3 in a concentration-dependent manner. Similar results were obtained using two other inhibitors of JAK3, WHI-P131 and WHI-P154. These biochemical changes were associated with apoptosis in both cell lines that was coupled with activation of caspase 3 and decreased bcl-xL and bcl-2. Cell cycle analysis revealed a decrease in the S phase, which may be attributed to cyclin D3 downregulation and p21(waf1) upregulation. Importantly, the tyrosine kinase activity of NPM-ALK, as assessed by an in vitro assay, decreased with increasing concentrations of AG490. Our findings highlight the importance of JAK3 in activating STAT3 in ALCL, and that NPM-ALK-mediated activation of STAT3 is influenced by the functional status of JAK3.
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PMID:Inhibition of JAK3 induces apoptosis and decreases anaplastic lymphoma kinase activity in anaplastic large cell lymphoma. 1293 99

Human myelogenous leukaemia K562 cells were induced to undergo megakaryocytic differentiation by treatment with phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) (20 nM, 24-72 h). The steady-state level of nucleophosmin/B23 mRNA decreased during the TPA-induced differentiation. There was also decrease in the level of cellular nucleophosmin/B23 protein and appearance of its degraded product (25 kDa) during the TPA-induced differentiation. Furthermore, K562/B23 (wild type), K562/D1 (delta280-294) and K562/D2 (delta263-294) cells were less, while K562/D3 (delta244-294) cells were more responsive to TPA-induced differentiation as compared to K562/vector or parental K562 cells. Activation of the ERK/MAPK was observed in parental K562 cells upon TPA treatment (5 nM, 5-30 min). As compared to K562/vector cells, less activation of ERK/MAPK was observed in K562/D2 cells, while ERK/MAPK was highly activated in K562/D3 cells upon TPA treatment. Our results indicate that nucleophosmin/B23 plays an important role in TPA-induced differentiation of K562 cells and the amino acids 244-294 at C-terminal of nucleophosmin/B23 could be an important site for regulation of cellular response to differentiation.
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PMID:Involvement of nucleophosmin/B23 in TPA-induced megakaryocytic differentiation of K562 cells. 1452 Apr 67

Accumulating evidence indicates that expression of anaplastic lymphoma kinase (ALK), typically due to t(2;5) translocation that creates an NPM-ALK fusion gene, defines a distinct type of T/null-cell lymphoma (TCL) within a vastly heterogeneous group of anaplastic large cell lymphomas. Through the translocation mechanism or as a full-length apparently intact protein, ALK also is expressed by a subset of inflammatory myofibroblastic tumors, glioblastomas, diffuse large B-cell lymphomas, and other malignant neoplasms. Owing to the recent progress in understanding its pathogenesis, ALK+ TCL has become a model malignant neoplasm in which morphology-based diagnosis and classification are gradually shifting toward biology-based diagnosis. Several lines of experimental evidence indicate that the ectopically expressed ALK is oncogenic in ALK+ TCL by being constitutively active owing to autophosphorylation and, consequently, by stimulating several critical signal transduction pathways involving phospholipase C-gamma, AKT, and STAT3 (signal transducer and activator of transcription 3). Targeting ALK and, perhaps, its downstream signaling effector proteins represents a promising novel therapeutic approach to ALK+ TCL. Diagnostic implications of the ALK expression in ALK+ TCL and other malignant neoplasms and the related current controversies are discussed.
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PMID:Expression of anaplastic lymphoma kinase in non-Hodgkin's lymphomas and other malignant neoplasms. Biological, diagnostic, and clinical implications. 1456 15

Anaplastic large cell lymphomas are associated with the t(2;5)(p23;q35) chromosome translocation in 40% to 60% of cases, leading to a new chimeric gene NPM-ALK. NPM-ALK positive lymphomas are generally reported to be of either T cell or null phenotype. In this report, we describe a diffuse large B-cell lymphoma associated with the classic t(2;5) translocation and both nuclear and cytoplasmic expression of ALK. The tumor consisted of medium-sized to large immunoblasts and plasmablasts that on immunohistology were negative for CD30, CD20, and CD79a but showed monotypic cytoplasmic expression of lambda light chains. Clonality analysis confirmed B-cell lineage of the tumor cells. The t(2;5)(p23;q35) chromosome translocation was demonstrated as part of a complex karyotypic alteration by classic banding and spectral karyotyping (SKY) analyses. Reverse transcription polymerase chain reaction confirmed rearrangement of NPM and ALK genes. This case exemplifies that the t(2;5) can, albeit rarely, occur in large B-cell lymphomas and is not entirely limited to anaplastic large cell lymphomas of T or null cell phenotypes.
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PMID:A case of a diffuse large B-cell lymphoma of plasmablastic type associated with the t(2;5)(p23;q35) chromosome translocation. 1457 83

Anaplastic large-cell lymphoma is associated with a chromosomal translocation generating an oncogenic fusion protein: the nucleophosmin-anaplastic lymphoma kinase (NPM-ALK). We have generated several independent lines of human NPM-ALK transgenic mice using the haematopoietic cell-specific Vav promoter. Lymphomas develop in two transgenic lines in which the Vav promoter regulates NPM-ALK expression. The transgenic line with higher copy number displays an early-onset phenotype in which all mice succumb to aggressive lymph node tumours with intestinal involvement, whereas the second line displays late-onset tumour development in the spleen and/or liver. Lymphomas from both lines are phenotypically distinct and display B-lineage characteristics with aberrant coexpression of myeloid markers. The NPM-ALK kinase is active in primary tumour tissue and forms a multimeric complex with tyrosine-phosphorylated proteins, that is, Shc. Jun and ERK kinase activities in tumours are elevated by up to 30-fold and fivefold, respectively, in comparison with sIgM-stimulated primary B cells. The new transgenic models provide a system for investigating the oncogenic events mediated by NPM-ALK in situ and a physiologically relevant context for developing tyrosine kinase inhibitor therapies of potential use in the clinic.
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PMID:Vav-promoter regulated oncogenic fusion protein NPM-ALK in transgenic mice causes B-cell lymphomas with hyperactive Jun kinase. 1458 1

Anaplastic large cell lymphomas (ALCLs) represent a heterogeneous group of malignant lymphoproliferative diseases. Most of the cases are of T-cell line with a loss of cell surface receptors but with a production of cytotoxic cytoplasmatic granules--immunohistochemically (IHC) positive perforin, granzyme B, and TIA-1. The diagnostics of ALCL is based on morphological findings and results of IHC, which further stratify ALCLs to basic immunophenotypes according to ALK (anaplastic lymphoma kinase) protein expression--ALCL CD30+ ALK+ and ALCL CD30+ ALK+. The morphological investigations are supplemented by karyotyping and/or by a demonstration of breakpoint at 2p23 harboring ALK gene (FISH), and by molecular detection of chimeric genes characteristic of ALK+ lymphomas (NPM-ALK, ATIC-ALK, TPM3-ALK, TFG-ALK, and some even rarer rearrangements). Molecular diagnostics is important in monitoring minimal residual disease. As some of the characteristic molecular changes were demonstrated in healthy individuals and in Hodgkin's disease by quantitative PCR, the validation of these findings demands further studies. ALK protein positive ALCLs affect patients in age categories up to the third decade, whereas ALK protein negative cases occur in older patients with an average age of 60 years. Both subgroups of lymphomas are aggressive but ALK+ lymphomas react well to systemic treatment, and have a more favorable prognosis. Primary skin ALCLs belong to a group of T-cell lymphoproliferative diseases of the skin and have, in the majority of cases, a favorable course without generalization.
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PMID:[Anaplastic large-cell lymphoma: review]. 1463 6

Deregulated apoptosis is a common finding in tumorigenesis. The oncogenic tyrosine kinase nucleophosmin/anaplastic lymphoma kinase (NPM/ALK) delivers a strong survival signal in anaplastic large cell lymphomas (ALCLs). Although NPM/ALK activates multiple antiapoptotic pathways, the biologic relevance and therapeutic potential of more downstream apoptotic effectors are mostly unknown. In this report, the NPM/ALK-mediated induction of Bcl-XL (but not of Bcl-2) was identified in human ALCL-derived cells. NPM/ALK kinase activity was required to promote Bcl-XL expression and its protective effect on mitochondrial homeostasis. Down-regulation of Bcl-XL significantly reduced the antiapoptotic potential of NPM/ALK in both transformed murine Ba/F3 pro-B cells and human ALCL-derived KARPAS-299 cells. To elucidate the role of Bcl-XL in vivo, Ba/F3-NPM/ALK+ cells expressing a doxycycline (Dox)-inducible Bcl-XL antisense transgene (pTet-ON) were injected into nude mice. Doxycycline administration prevented a fatal systemic disease in 15 of 15 intravenously injected mice and the appearance of subcutaneous tumor xenografts in 9 of 12 mice; in vivo down-regulation of Bcl-XL was also documented. Our results show a pivotal role for Bcl-XL in ALK-mediated oncogenicity; a single protein placed downstream of a known oncogene can be crucial for the survival of neoplastic cells both in vitro and in vivo. Bcl-XL deserves further investigation as a possible therapeutic target in ALK+ ALCLs.
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PMID:Bcl-XL down-regulation suppresses the tumorigenic potential of NPM/ALK in vitro and in vivo. 1465 79

The requirement for sufficient quantities of starting RNA has limited the ability to evaluate multiple transcripts using reverse transcriptase-polymerase chain reaction (RT-PCR). In this study, we demonstrate the utility of linear RNA amplification for RT-PCR analysis of multiple gene transcripts including a chromosomal translocation, using the t(2;5)(p23;q35) as a model. RNA from the t(2;5)-positive cell line, SU-DHL-1, and the t(2;5)-negative cell line, HUT-78, was extracted and exposed to two rounds of linear amplification. RT-PCR using cDNA from the resultant amplified (a) RNA and total RNA resulted in the 177 bp NPM-ALK fusion gene product from the SU-DHL-1 cell line, but not from aRNA or total RNA from the HUT-78 cell line. DNA sequencing of the RT-PCR products from total and aRNA of SU-DHL-1 cells demonstrated identical sequences corresponding to the NPM-ALK fusion gene. Evaluation of 25 snap-frozen tissue samples, including eight NPM-ALK-positive ALCLs demonstrated 100% concordance of t(2;5) detection between cDNA from total RNA and that from aRNA. Our results show that linear amplification of RNA can enhance starting RNA greater than 200-fold and can be used for rapid and specific detection of multiplex gene expression from a variety of sources. This method can generate a renewable archive of representative cDNA, which can be used for retrospective screening of stored samples as well as positive controls for the clinical molecular diagnostic laboratory.
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PMID:Utility of linearly amplified RNA for RT-PCR detection of chromosomal translocations: validation using the t(2;5)(p23;q35) NPM-ALK chromosomal translocation. 1473 22


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