NPM-ALK Converts JUNB from a Tumor Suppressor to an Oncogene.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1448-1448
Author(s):  
Paul Vesely ◽  
Philipp B. Staber ◽  
Rene Ott ◽  
Montserrat Pinent ◽  
Werner Linkesch ◽  
...  
Keyword(s):  
Tumor Suppressor ◽  
Tumor Necrosis Factor Receptor ◽  
Large Cell ◽  
Cell Types ◽  
Wild Type ◽  
Anaplastic Lymphoma ◽  
Supershift Assay ◽  
Factor C ◽  
Electro Mobility ◽  
Opposing Effects

Abstract High expression of the tumor necrosis factor receptor CD30 and the AP-1 transcription factor JunB are the hallmark of anaplastic large cell lymphoma (ALCL). In contrast to the prototypic AP-1 factor c-Jun, JunB exerts an antioncogenic function in most cell types. Its functional role in ALCL remains uncertain. In about 50% of nodal ALCL the balanced chromosomal rearrangement t(2;5)(p23;q35), generating the fusion protein nucleophosmin-anaplastic lymphoma kinase (NPM-ALK), can be detected. Expression of this fusion kinase induces malignancy in mice and also leads to IL-3 independent outgrowth of the murine hematopoietic cell line Ba/F3. Using NPM-ALK transduced Ba/F3 cells, we show that NPM-ALK induces JunB expression and activation as verified by quantitative RT-PCR, immunoblot and electro-mobility supershift assay. Interestingly, NPM-ALK transduced Ba/F3 cells also express CD30, which is undetectable in the corresponding wild type cells. Since NPM-ALK induces JunB and CD30 and also leads to growth factor independent proliferation in Ba/F3 cells, these cells mimic conditions present in ALCL. Knock down of JUNB in NPM-ALK expressing cells using RNA interference leads to downregulation of CD30. Moreover, this partial loss of JunB induces upregulation of p16INK4a and downregulation of CCND1, which directly affect the cell cycle at the G1/S transition. These observations indicate that JunB is an essential factor for CD30 regulation and for neoplastic transformation. To test if JunB by itself is sufficient to induce CD30 expression and IL-3 independence, we stably transduced Ba/F3 cells with JUNB. In Ba/F3 wild type (WT) cells, JunB expression leads to reverse effects compared to that observed in NPM-ALK transduced Ba/F3. Ba/F3 WT cells do not become IL-3 independent. In addition, compared to vector control, JUNB-transduced Ba/F3 cells show a decrease in proliferation. Furthermore, an induction of p16INK4a and a decrease of CCND1 expression are observed. Moreover, aberrant JunB expression does not trigger CD30 expression in this system. Taken together, we show that both NPM-ALK and JunB are essential to induce CD30 expression. Furthermore the opposing effects of JunB on p16INK4a and CCND1 in the presence or absence of NPM-ALK indicate that NPM-ALK converts JUNB from a tumor suppressor to an oncogene.

scholarly journals Challenging perspectives on the cellular origins of lymphoma

Open Biology ◽  
2016 ◽  
Vol 6 (9) ◽  
pp. 160232 ◽  
Author(s):  
Tim I. M. Malcolm ◽  
Daniel J. Hodson ◽  
Elizabeth A. Macintyre ◽  
Suzanne D. Turner
Keyword(s):  
T Cell ◽  
Cell Lymphoma ◽  
Adaptive Immune Response ◽  
Antigen Receptor ◽  
Large Cell ◽  
Cell Types ◽  
Infectious Agents ◽  
Antigen Receptors ◽  
Cell Of Origin ◽  
Anaplastic Lymphoma

Both B and T lymphocytes have signature traits that set them apart from other cell types. They actively and repeatedly rearrange their DNA in order to produce a unique and functional antigen receptor, they have potential for massive clonal expansion upon encountering antigen via this receptor or its precursor, and they have the capacity to be extremely long lived as ‘memory’ cells. All three of these traits are fundamental to their ability to function as the adaptive immune response to infectious agents, but concurrently render these cells vulnerable to transformation. Thus, it is classically considered that lymphomas arise at a relatively late stage in a lymphocyte's development during the process of modifying diversity within antigen receptors, and when the cell is capable of responding to stimulus via its receptor. Attempts to understand the aetiology of lymphoma have reinforced this notion, as the most notable advances to date have shown chronic stimulation of the antigen receptor by infectious agents or self-antigens to be key drivers of these diseases. Despite this, there is still uncertainty about the cell of origin in some lymphomas, and increasing evidence that a subset arises in a more immature cell. Specifically, a recent study indicates that T-cell lymphoma, in particular nucleophosmin-anaplastic lymphoma kinase-driven anaplastic large cell lymphoma, may originate in T-cell progenitors in the thymus.

NPM-ALK inhibits the p53 tumor suppressor pathway in an MDM2 and JNK-dependent manner

Blood ◽  
2009 ◽  
Vol 113 (21) ◽  
pp. 5217-5227 ◽  
Author(s):  
Yu-Xin Cui ◽  
Alan Kerby ◽  
Fiona Kate Elizabeth McDuff ◽  
Hongtao Ye ◽  
Suzanne Dawn Turner
Keyword(s):  
Tumor Suppressor ◽  
Protein A ◽  
Large Cell ◽  
Negative Regulator ◽  
Therapeutic Modality ◽  
Dependent Manner ◽  
P53 Tumor Suppressor ◽  
Anaplastic Lymphoma ◽  
Nuclear Exclusion ◽  
Functional Inactivation

Abstract Anaplastic large cell lymphoma (ALCL) is characterized by the presence of the t(2;5)(p23;q35) generating the nucleophosmin-anaplastic lymphoma kinase (NPM-ALK) fusion protein, a hyperactive kinase with transforming properties. Among these properties is the ability to regulate activity of the p53 tumor suppressor protein. In many human cancers, p53 is inactivated by mutation or other means, in some cases as a result of up-regulation of the negative regulator MDM2. However, the majority of ALK-expressing ALCL carry wild-type p53 and do not over express MDM2. We demonstrate a novel p53-dependent pathogenetic mechanism in ALK-expressing lymphoma. We confirm previously published reports of NPM-ALK–induced activation of the phosphoinositide (PI) 3-kinase and Jun N-terminal kinase (JNK) stress-activated protein (SAP) kinase proteins, but in this study demonstrate a role for these in the regulation of p53 activity in an intricate signaling system. Specifically, constitutive ALK signaling leads to the functional inactivation and/or degradation of p53 in JNK and MDM2 dependent manners. We also show nuclear exclusion of p53 in a PI 3-kinase–dependent manner. Furthermore, we demonstrate that reactivation of p53 in ALK-expressing cells as a result of pharmacologic inhibition of JNK, PI 3-kinase, and/or MDM2 activities results in the induction of apoptosis suggesting a novel therapeutic modality.

Identification of Critical Phosporylation Sites within NPM-ALK That Regulate JUNB mRNA Translation.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3571-3571
Author(s):  
Claudia Fuchs ◽  
Paul Vesely ◽  
Isabella Bambach ◽  
Silvia Schauer ◽  
Werner Linkesch ◽  
...  
Keyword(s):  
Tyrosine Kinases ◽  
Translational Regulation ◽  
Chromosomal Translocation ◽  
Mrna Translation ◽  
Large Cell ◽  
Wild Type ◽  
Tyrosine Residues ◽  
Anaplastic Lymphoma ◽  
Rps6 Phosphorylation ◽  
Mutant Cells

Abstract Anaplastic large cell lymphoma (ALCL) accounts for approximately 30% of childhood lymphomas and 3% of adult non-Hodgkin lymphomas. The nucleophosmin - anaplastic lymphoma kinase (NPM-ALK) fusion which is the product of a t(2;5)(p23;q35) chromosomal translocation is present in about half of nodal ALCL. Expression of this fusion kinase results in induction of the AP-1 transcription factor JunB and IL-3 independent outgrow of murine hematopoietic Ba/F3 cells. We demonstrated that wild type NPM-ALK increases the amount of ribosomes bound to JUNB mRNA resulting in its more effective translation in large polysomes. The NPM-ALK fusion tyrosine kinase has 20 potential tyrosine residues available for autophosphorylation and phosphorylation by other protein tyrosine kinases. Here we used series of Y-to-F-substituted mutants of NPM-ALK to identify tyrosine residues that are required to regulate the segregation of JUNB mRNAs between polysomes and monosomes as well as ribonucleic particles (RNPs). Neither JUNB transcription nor JunB translation was altered in Ba/F3 cells expressing NPM-ALK mutants Y17F/Y29F/Y67F Y138F/Y152F Y156F/Y191F/Y299F Y378F/Y418F/Y445F and Y646F/Y664F compared to NPM-ALK wild type. Conversely, in NPM-ALK Y567F/Y461F/Y644F mutant cells proliferation was markedly decreased. These cells demonstrated active MEK-ERK pathway, while AKT, mTOR, and rpS6 phosphorylation was impaired. Moreover a shift of JUNB mRNA from the polysomic to the monosomic/mRNP fraction could be observed. In conclusion, we identified specific NPM-ALK phosphorylation sites required to mediate the effect of NPM-ALK on the JUNB translational regulation and therefore provide further insights in the transforming mechanisms of the oncoprotein NPM-ALK.

scholarly journals Yeast Lacking theSRO7/SOP1-encoded Tumor Suppressor Homologue Show Increased Susceptibility to Apoptosis-like Cell Death on Exposure to NaCl Stress

2004 ◽  
Vol 15 (3) ◽  
pp. 1436-1444 ◽  
Author(s):  
Ingrid Wadskog ◽  
Corinna Maldener ◽  
Astrid Proksch ◽  
Frank Madeo ◽  
Lennart Adler
Keyword(s):  
Cell Death ◽  
Tumor Suppressor ◽  
Nacl Stress ◽  
Yeast Cells ◽  
Wild Type ◽  
Nuclear Fragmentation ◽  
Dna Breakage ◽  
Increased Sensitivity ◽  
Opposing Effects ◽  
Growth Inhibiting

Yeast cells deleted for the SRO7/SOP1 encoded tumor suppressor homologue show increased sensitivity to NaCl stress. On exposure to growth-inhibiting NaCl concentrations, sro7Δ mutants display a rapid loss in viability that is associated with markers of apoptosis: accumulation of reactive oxygen species, DNA breakage, and nuclear fragmentation. Additional deletion of the yeast metacaspase gene YCA1 prevents the primary fast drop in viability and diminishes nuclear fragmentation and DNA breakage. We also observed that NaCl induced loss in viability of wild-type cells is Yca1p dependent. However, a yeast strain deleted for both SRO7 and its homologue SRO77 exhibits NaCl-induced cell death that is independent on YCA1. Likewise, sro77Δ single mutants do not survive better after additional deletion of the YCA1 gene, and both sro77Δ and sro77Δyca1Δ mutants display apoptotic characteristics when exposed to growth-inhibiting salinity, suggesting that yeast possesses Yca1p-independent pathway(s) for apoptosis-like cell death. The activity of Yca1p increases with increasing NaCl stress and sro7Δ mutants achieve levels that are higher than in wild-type cells. However, mutants lacking SRO77 do not enhance caspase activity when subject to NaCl stress, suggesting that Sro7p and Sro77p exert opposing effects on the cellular activity of Yca1p.

scholarly journals Increased Tenascin C, Osteopontin and HSP90 Levels in Plasmatic Small Extracellular Vesicles of Pediatric ALK-Positive Anaplastic Large Cell Lymphoma: New Prognostic Biomarkers?

Diagnostics ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 253
Author(s):  
Federica Lovisa ◽  
Anna Garbin ◽  
Sara Crotti ◽  
Piero Di Battista ◽  
Ilaria Gallingani ◽  
...  
Keyword(s):  
Extracellular Vesicles ◽  
Anaplastic Large Cell Lymphoma ◽  
Cell Lymphoma ◽  
Enrichment Analysis ◽  
Heat Shock Protein 90 ◽  
Large Cell ◽  
Tenascin C ◽  
Anaplastic Lymphoma ◽  
Large Cell Lymphoma ◽  
Alk Positive

Over the past 15 years, several biological and pathological characteristics proved their significance in pediatric anaplastic lymphoma kinase (ALK)-positive anaplastic large-cell lymphoma (ALCL) prognostic stratification. However, the identification of new non-invasive disease biomarkers, relying on the most important disease mechanisms, is still necessary. In recent years, plasmatic circulating small extracellular vesicles (S-EVs) gathered great importance both as stable biomarker carriers and active players in tumorigenesis. In the present work, we performed a comprehensive study on the proteomic composition of plasmatic S-EVs of pediatric ALCL patients compared to healthy donors (HDs). By using a mass spectrometry-based proteomics approach, we identified 50 proteins significantly overrepresented in S-EVs of ALCL patients. Gene Ontology enrichment analysis disclosed cellular components and molecular functions connected with S-EV origin and vesicular trafficking, whereas cell adhesion, glycosaminoglycan metabolic process, extracellular matrix organization, collagen fibril organization and acute phase response were the most enriched biological processes. Of importance, consistently with the presence of nucleophosmin (NPM)-ALK fusion protein in ALCL cells, a topological enrichment analysis based on Reactome- and Kyoto Encyclopedia of Genes and Genomes (KEGG)-derived networks highlighted a dramatic increase in proteins of the phosphatidylinositol 3-kinase (PI3K)/AKT pathway in ALCL S-EVs, which included heat shock protein 90-kDa isoform alpha 1 (HSP90AA1), osteopontin (SPP1/OPN) and tenascin C (TNC). These results were validated by Western blotting analysis on a panel of ALCL and HD cases. Further research is warranted to better define the role of these S-EV proteins as diagnostic and, possibly, prognostic parameters at diagnosis and for ALCL disease monitoring.

scholarly journals The AML-associated K313 mutation enhances C/EBPα activity by leading to C/EBPα overexpression

2021 ◽  
Vol 12 (7) ◽  
Author(s):  
Ian Edward Gentle ◽  
Isabel Moelter ◽  
Mohamed Tarek Badr ◽  
Konstanze Döhner ◽  
Michael Lübbert ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Culture ◽  
Transcription Factor ◽  
Transcription Factors ◽  
Transcriptional Activity ◽  
Target Gene ◽  
Wild Type ◽  
Elevated Expression ◽  
Factor C ◽  
Acute Myeloid

AbstractMutations in the transcription factor C/EBPα are found in ~10% of all acute myeloid leukaemia (AML) cases but the contribution of these mutations to leukemogenesis is incompletely understood. We here use a mouse model of granulocyte progenitors expressing conditionally active HoxB8 to assess the cell biological and molecular activity of C/EBPα-mutations associated with human AML. Both N-terminal truncation and C-terminal AML-associated mutations of C/EBPα substantially altered differentiation of progenitors into mature neutrophils in cell culture. Closer analysis of the C/EBPα-K313-duplication showed expansion and prolonged survival of mutant C/EBPα-expressing granulocytes following adoptive transfer into mice. C/EBPα-protein containing the K313-mutation further showed strongly enhanced transcriptional activity compared with the wild-type protein at certain promoters. Analysis of differentially regulated genes in cells overexpressing C/EBPα-K313 indicates a strong correlation with genes regulated by C/EBPα. Analysis of transcription factor enrichment in the differentially regulated genes indicated a strong reliance of SPI1/PU.1, suggesting that despite reduced DNA binding, C/EBPα-K313 is active in regulating target gene expression and acts largely through a network of other transcription factors. Strikingly, the K313 mutation caused strongly elevated expression of C/EBPα-protein, which could also be seen in primary K313 mutated AML blasts, explaining the enhanced C/EBPα activity in K313-expressing cells.

scholarly journals Microtubule–microtubule sliding by kinesin-1 is essential for normal cytoplasmic streaming in Drosophila oocytes

2016 ◽  
Vol 113 (34) ◽  
pp. E4995-E5004 ◽  
Author(s):  
Wen Lu ◽  
Michael Winding ◽  
Margot Lakonishok ◽  
Jill Wildonger ◽  
Vladimir I. Gelfand
Keyword(s):  
Cytoplasmic Streaming ◽  
Cell Types ◽  
Nurse Cells ◽  
Wild Type ◽  
Actin Cortex ◽  
Microtubule Motor ◽  
Multiple Cell ◽  
Cytoplasmic Microtubules ◽  
Two Populations

Cytoplasmic streaming in Drosophila oocytes is a microtubule-based bulk cytoplasmic movement. Streaming efficiently circulates and localizes mRNAs and proteins deposited by the nurse cells across the oocyte. This movement is driven by kinesin-1, a major microtubule motor. Recently, we have shown that kinesin-1 heavy chain (KHC) can transport one microtubule on another microtubule, thus driving microtubule–microtubule sliding in multiple cell types. To study the role of microtubule sliding in oocyte cytoplasmic streaming, we used a Khc mutant that is deficient in microtubule sliding but able to transport a majority of cargoes. We demonstrated that streaming is reduced by genomic replacement of wild-type Khc with this sliding-deficient mutant. Streaming can be fully rescued by wild-type KHC and partially rescued by a chimeric motor that cannot move organelles but is active in microtubule sliding. Consistent with these data, we identified two populations of microtubules in fast-streaming oocytes: a network of stable microtubules anchored to the actin cortex and free cytoplasmic microtubules that moved in the ooplasm. We further demonstrated that the reduced streaming in sliding-deficient oocytes resulted in posterior determination defects. Together, we propose that kinesin-1 slides free cytoplasmic microtubules against cortically immobilized microtubules, generating forces that contribute to cytoplasmic streaming and are essential for the refinement of posterior determinants.

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