Nanostructure of clustered DNA damage in leukocytes after in-solution irradiation with the alpha emitter Ra-223

• Verfasst von: Scherthan, Harry [VerfasserIn]
• Verfasst von: Chojowski, Robert [VerfasserIn]
• Verfasst von: Hausmann, Michael [VerfasserIn]
• Titel: Nanostructure of clustered DNA damage in leukocytes after in-solution irradiation with the alpha emitter Ra-223
• Verf.angabe: Harry Scherthan, Jin-Ho Lee, Emanuel Maus, Sarah Schumann, Razan Muhtadi, Robert Chojowski, Matthias Port, Michael Lassmann, Felix Bestvater and Michael Hausmann
• E-Jahr: 2019
• Jahr: 26 November 2019
• Umfang: 23 S.
• Fussnoten: Gesehen am 18.02.2020
• Titel Quelle: Enthalten in: Cancers
• Ort Quelle: Basel : MDPI, 2009
• Jahr Quelle: 2019
• Band/Heft Quelle: 11(2019,12) Artikel-Nummer 1877, 23 Seiten
• ISSN Quelle: 2072-6694
• DOI: doi:10.3390/cancers11121877
• Datenträger: Online-Ressource
• Sprache: eng
• Sach-SW: complex DNA damage
• Sach-SW: DNA repair
• Sach-SW: DSB focus substructure
• Sach-SW: high LET irradiation
• Sach-SW: Single Molecule Localization Microscopy (SMLM)
• K10plus-PPN: 1690253126

Abstract

Background: Cancer patients are increasingly treated with alpha-particle-emitting radiopharmaceuticals. At the subcellular level, alpha particles induce densely spaced ionizations and molecular damage. Induction of DNA lesions, especially clustered DNA double-strand breaks (DSBs), threatens a cell’s survival. Currently, it is under debate to what extent the spatial topology of the damaged chromatin regions and the repair protein arrangements are contributing. Methods: Super-resolution light microscopy (SMLM) in combination with cluster analysis of single molecule signal-point density regions of DSB repair markers was applied to investigate the nano-structure of DNA damage foci tracks of Ra-223 in-solution irradiated leukocytes. Results: Alpha-damaged chromatin tracks were efficiently outlined by γ-H2AX that formed large (super) foci composed of numerous 60–80 nm-sized nano-foci. Alpha damage tracks contained 60–70% of all γ-H2AX point signals in a nucleus, while less than 30% of 53BP1, MRE11 or p-ATM signals were located inside γ-H2AX damage tracks. MRE11 and p-ATM protein fluorescent tags formed focal nano-clusters of about 20 nm peak size. There were, on average, 12 (±9) MRE11 nanoclusters in a typical γ-H2AX-marked alpha track, suggesting a minimal number of MRE11-processed DSBs per track. Our SMLM data suggest regularly arranged nano-structures during DNA repair in the damaged chromatin domain.