Phosphoproteome Profiling Reveals Multifunctional Protein NPM1 as part of the Irradiation Response of Tumor Cells

To fight resistances to radiotherapy, the understanding of escape mechanisms of tumor cells is crucial. The aim of this study was to identify phosphoproteins that are regulated upon irradiation. The comparative analysis of the phosphoproteome before and after irradiation brought nucleophosmin (NPM1)...

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Main Authors: Nadine Wiesmann, Rita Gieringer, Franz Grus, Juergen Brieger
Format: Article
Language:English
Published: Elsevier 2019-02-01
Series:Translational Oncology
Online Access:http://www.sciencedirect.com/science/article/pii/S1936523318304959
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author Nadine Wiesmann
Rita Gieringer
Franz Grus
Juergen Brieger
author_facet Nadine Wiesmann
Rita Gieringer
Franz Grus
Juergen Brieger
author_sort Nadine Wiesmann
collection DOAJ
description To fight resistances to radiotherapy, the understanding of escape mechanisms of tumor cells is crucial. The aim of this study was to identify phosphoproteins that are regulated upon irradiation. The comparative analysis of the phosphoproteome before and after irradiation brought nucleophosmin (NPM1) into focus as a versatile phosphoprotein that has already been associated with tumorigenesis. We could show that knockdown of NPM1 significantly reduces tumor cell survival after irradiation. NPM1 is dephosphorylated stepwise within 1 hour after irradiation at two of its major phosphorylation sites: threonine-199 and threonine-234/237. This dephosphorylation is not the result of a fast cell cycle arrest, and we found a heterogenous intracellular distribution of NPM1 between the nucleoli, the nucleoplasm, and the cytoplasm after irradiation. We hypothesize that the dephosphorylation of NPM1 at threonine-199 and threonine-234/237 is part of the immediate response to irradiation and of importance for tumor cell survival. These findings could make NPM1 an attractive pharmaceutical target to radiosensitize tumor cells and improve the outcome of radiotherapy by inhibiting the pathways that help tumor cells to escape cell death after gamma irradiation.
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spelling doaj.art-4010cabed4b14de581f1cda2a8a512c22022-12-21T18:33:26ZengElsevierTranslational Oncology1936-52332019-02-01122308319Phosphoproteome Profiling Reveals Multifunctional Protein NPM1 as part of the Irradiation Response of Tumor CellsNadine Wiesmann0Rita Gieringer1Franz Grus2Juergen Brieger3Molecular Tumor Biology, Department of Otorhinolaryngology, Head and Neck Surgery, University Medical Centre of the Johannes Gutenberg University, Langenbeckstraße 1, 55131 Mainz, GermanyMolecular Tumor Biology, Department of Otorhinolaryngology, Head and Neck Surgery, University Medical Centre of the Johannes Gutenberg University, Langenbeckstraße 1, 55131 Mainz, GermanyExperimental Ophthalmology, Department of Ophthalmology, University Medical Center of the Johannes Gutenberg University Mainz, Langenbeckstraße 1, 55131 Mainz, GermanyMolecular Tumor Biology, Department of Otorhinolaryngology, Head and Neck Surgery, University Medical Centre of the Johannes Gutenberg University, Langenbeckstraße 1, 55131 Mainz, Germany; Address all correspondence to: Juergen Brieger, Molecular Tumor Biology, Department of Otorhinolaryngology, Head and Neck Surgery, University Medical Centre of the Johannes Gutenberg University, Langenbeckstraße 1, 55131 Mainz, Germany.To fight resistances to radiotherapy, the understanding of escape mechanisms of tumor cells is crucial. The aim of this study was to identify phosphoproteins that are regulated upon irradiation. The comparative analysis of the phosphoproteome before and after irradiation brought nucleophosmin (NPM1) into focus as a versatile phosphoprotein that has already been associated with tumorigenesis. We could show that knockdown of NPM1 significantly reduces tumor cell survival after irradiation. NPM1 is dephosphorylated stepwise within 1 hour after irradiation at two of its major phosphorylation sites: threonine-199 and threonine-234/237. This dephosphorylation is not the result of a fast cell cycle arrest, and we found a heterogenous intracellular distribution of NPM1 between the nucleoli, the nucleoplasm, and the cytoplasm after irradiation. We hypothesize that the dephosphorylation of NPM1 at threonine-199 and threonine-234/237 is part of the immediate response to irradiation and of importance for tumor cell survival. These findings could make NPM1 an attractive pharmaceutical target to radiosensitize tumor cells and improve the outcome of radiotherapy by inhibiting the pathways that help tumor cells to escape cell death after gamma irradiation.http://www.sciencedirect.com/science/article/pii/S1936523318304959
spellingShingle Nadine Wiesmann
Rita Gieringer
Franz Grus
Juergen Brieger
Phosphoproteome Profiling Reveals Multifunctional Protein NPM1 as part of the Irradiation Response of Tumor Cells
Translational Oncology
title Phosphoproteome Profiling Reveals Multifunctional Protein NPM1 as part of the Irradiation Response of Tumor Cells
title_full Phosphoproteome Profiling Reveals Multifunctional Protein NPM1 as part of the Irradiation Response of Tumor Cells
title_fullStr Phosphoproteome Profiling Reveals Multifunctional Protein NPM1 as part of the Irradiation Response of Tumor Cells
title_full_unstemmed Phosphoproteome Profiling Reveals Multifunctional Protein NPM1 as part of the Irradiation Response of Tumor Cells
title_short Phosphoproteome Profiling Reveals Multifunctional Protein NPM1 as part of the Irradiation Response of Tumor Cells
title_sort phosphoproteome profiling reveals multifunctional protein npm1 as part of the irradiation response of tumor cells
url http://www.sciencedirect.com/science/article/pii/S1936523318304959
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