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Abstract 1 Distinctive and Differentiation-State Dependent DNA Damage Response of Hematopoietic Stem Cells to Genotoxic Noxae
INTRODUCTION: Hematopoietic stem cells (HSCs) sustain lifelong blood production and can be used in allogenic stem cell transplantation for treatment of hematological malignancies, yet the mechanisms of their DNA damage response (DDR) remain largely unexplored. Genotoxic damage can be induced by chem...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Oxford University Press
2022
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9446908/ http://dx.doi.org/10.1093/stcltm/szac057.001 |
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author | Becker, Fabienne Ouzin, Meryem Lucks, Luzie Christ, Kathrin Liedtke, Stefanie Kögler, Gesine |
author_facet | Becker, Fabienne Ouzin, Meryem Lucks, Luzie Christ, Kathrin Liedtke, Stefanie Kögler, Gesine |
author_sort | Becker, Fabienne |
collection | PubMed |
description | INTRODUCTION: Hematopoietic stem cells (HSCs) sustain lifelong blood production and can be used in allogenic stem cell transplantation for treatment of hematological malignancies, yet the mechanisms of their DNA damage response (DDR) remain largely unexplored. Genotoxic damage can be induced by chemotherapeutical agents (eg, etoposide, a topoisomerase II inhibitor) or by methylating agents (eg, nitrosamines). Related double strand breaks (DSBs) at the level of immature cells are thus presumed to trigger leukemia. OBJECTIVE: Human quiescent and cycling HSCs were reported to exhibit distinct responses to genotoxic stress upon in vitro exposure to sublethal doses of etoposide or N-nitroso-N-methylurea (MNU). In this context, we aim to identify and compare the mechanisms involved in the determination of HSC stem and progenitor cell fate upon DNA damage to gain more insights into cytotoxic anticancer drug- and contaminant-related hematological toxicity. METHODS: Quiescent human HSCs (CD34(+)) were isolated from umbilical cord blood, sorted and directly exposed to etoposide or MNU. Besides, CD34(+) were expanded in-vitro in medium containing broad acting cytokines for 5 days prior genotoxic exposure. Sublethal doses were assessed by Alamar Blue assay. Propidium iodide staining and colony-forming unit assay (CFU) were used for cell cycle analysis and tracking of cell functionality. RESULTS: In vitro inhibitory concentrations were identified for human HSCs treated with etoposide (IC(50) = 5 µM) and MNU (IC(50) = 1 mM). Treatment of quiescent HSCs with lower genotoxin concentrations induces a cell cycle arrest in the G(0)/G(1)-phase, whereas higher concentrations activate apoptosis-related genes and completely abrogate further differentiation into colony-forming progenitors. In contrast, cycling HSCs exhibit an impaired proliferation, upregulation of autophagy-related genes, reduced proportions of viable CD34(+) cells, and similar effects regarding differentiation capacity into colony-forming progenitors. However, cells exposed to lower genotoxin doses exhibit a higher regeneration capacity 3 days upon treatment. DISCUSSION: These results confirm that the DDR following DSB-induction differs between quiescent and cycling HSCs. Quiescent HSCs exhibit a stronger DDR, probably related to their longer lifespan. To avoid malignant transformation, it is necessary to preclude damage accumulation through cell cycle withdrawal and apoptosis. In contrast, more committed cells rather inline toward damage repair and restoration through activation of, for example, non-homologous end joining or mismatch repair genes. |
format | Online Article Text |
id | pubmed-9446908 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | Oxford University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-94469082022-09-06 Abstract 1 Distinctive and Differentiation-State Dependent DNA Damage Response of Hematopoietic Stem Cells to Genotoxic Noxae Becker, Fabienne Ouzin, Meryem Lucks, Luzie Christ, Kathrin Liedtke, Stefanie Kögler, Gesine Stem Cells Transl Med Preclinical Studies INTRODUCTION: Hematopoietic stem cells (HSCs) sustain lifelong blood production and can be used in allogenic stem cell transplantation for treatment of hematological malignancies, yet the mechanisms of their DNA damage response (DDR) remain largely unexplored. Genotoxic damage can be induced by chemotherapeutical agents (eg, etoposide, a topoisomerase II inhibitor) or by methylating agents (eg, nitrosamines). Related double strand breaks (DSBs) at the level of immature cells are thus presumed to trigger leukemia. OBJECTIVE: Human quiescent and cycling HSCs were reported to exhibit distinct responses to genotoxic stress upon in vitro exposure to sublethal doses of etoposide or N-nitroso-N-methylurea (MNU). In this context, we aim to identify and compare the mechanisms involved in the determination of HSC stem and progenitor cell fate upon DNA damage to gain more insights into cytotoxic anticancer drug- and contaminant-related hematological toxicity. METHODS: Quiescent human HSCs (CD34(+)) were isolated from umbilical cord blood, sorted and directly exposed to etoposide or MNU. Besides, CD34(+) were expanded in-vitro in medium containing broad acting cytokines for 5 days prior genotoxic exposure. Sublethal doses were assessed by Alamar Blue assay. Propidium iodide staining and colony-forming unit assay (CFU) were used for cell cycle analysis and tracking of cell functionality. RESULTS: In vitro inhibitory concentrations were identified for human HSCs treated with etoposide (IC(50) = 5 µM) and MNU (IC(50) = 1 mM). Treatment of quiescent HSCs with lower genotoxin concentrations induces a cell cycle arrest in the G(0)/G(1)-phase, whereas higher concentrations activate apoptosis-related genes and completely abrogate further differentiation into colony-forming progenitors. In contrast, cycling HSCs exhibit an impaired proliferation, upregulation of autophagy-related genes, reduced proportions of viable CD34(+) cells, and similar effects regarding differentiation capacity into colony-forming progenitors. However, cells exposed to lower genotoxin doses exhibit a higher regeneration capacity 3 days upon treatment. DISCUSSION: These results confirm that the DDR following DSB-induction differs between quiescent and cycling HSCs. Quiescent HSCs exhibit a stronger DDR, probably related to their longer lifespan. To avoid malignant transformation, it is necessary to preclude damage accumulation through cell cycle withdrawal and apoptosis. In contrast, more committed cells rather inline toward damage repair and restoration through activation of, for example, non-homologous end joining or mismatch repair genes. Oxford University Press 2022-09-06 /pmc/articles/PMC9446908/ http://dx.doi.org/10.1093/stcltm/szac057.001 Text en © The Author(s) 2022. Published by Oxford University Press. https://creativecommons.org/licenses/by-nc-nd/4.0/This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs licence (https://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reproduction and distribution of the work, in any medium, provided the original work is not altered or transformed in any way, and that the work is properly cited. For commercial re-use, please contact journals.permissions@oup.com |
spellingShingle | Preclinical Studies Becker, Fabienne Ouzin, Meryem Lucks, Luzie Christ, Kathrin Liedtke, Stefanie Kögler, Gesine Abstract 1 Distinctive and Differentiation-State Dependent DNA Damage Response of Hematopoietic Stem Cells to Genotoxic Noxae |
title | Abstract 1 Distinctive and Differentiation-State Dependent DNA Damage Response of Hematopoietic Stem Cells to Genotoxic Noxae |
title_full | Abstract 1 Distinctive and Differentiation-State Dependent DNA Damage Response of Hematopoietic Stem Cells to Genotoxic Noxae |
title_fullStr | Abstract 1 Distinctive and Differentiation-State Dependent DNA Damage Response of Hematopoietic Stem Cells to Genotoxic Noxae |
title_full_unstemmed | Abstract 1 Distinctive and Differentiation-State Dependent DNA Damage Response of Hematopoietic Stem Cells to Genotoxic Noxae |
title_short | Abstract 1 Distinctive and Differentiation-State Dependent DNA Damage Response of Hematopoietic Stem Cells to Genotoxic Noxae |
title_sort | abstract 1 distinctive and differentiation-state dependent dna damage response of hematopoietic stem cells to genotoxic noxae |
topic | Preclinical Studies |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9446908/ http://dx.doi.org/10.1093/stcltm/szac057.001 |
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