NF-κB-dependent DNA damage-signaling differentially regulates DNA double-strand break repair mechanisms in immature and mature human hematopoietic cells.
Leukemia
; 29(7): 1543-54, 2015 Jul.
Article
in En
| MEDLINE
| ID: mdl-25652738
ABSTRACT
Hematopoietic stem and progenitor cells (HSPC), that is, the cell population giving rise not only to all mature hematopoietic lineages but also the presumed target for leukemic transformation, can transmit (adverse) genetic events, such as are acquired from chemotherapy or ionizing radiation. Data on the repair of DNA double-strand-breaks (DSB) and its accuracy in HSPC are scarce, in part contradictory, and mostly obtained in murine models. We explored the activity, quality and molecular components of DSB repair in human HSPC as compared with mature peripheral blood lymphocytes (PBL). To consider chemotherapy/radiation-induced compensatory proliferation, we established cycling HSPC cultures. Comparison of pathway-specific repair activities using reporter systems revealed that HSPC were severely compromised in non-homologous end joining and homologous recombination but not microhomology-mediated end joining. We observed a more pronounced radiation-induced accumulation of nuclear 53BP1 in HSPC relative to PBL, despite evidence for comparable DSB formation from cytogenetic analysis and γH2AX signal quantification, supporting differential pathway usage. Functional screening excluded a major influence of phosphatidylinositol-3-OH-kinase (ATM/ATR/DNA-PK)- and p53-signaling as well as chromatin remodeling. We identified diminished NF-κB signaling as the molecular component underlying the observed differences between HSPC and PBL, limiting the expression of DSB repair genes and bearing the risk of an inaccurate repair.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Hematopoietic Stem Cells
/
Lymphocytes
/
Cell Transformation, Neoplastic
/
NF-kappa B
/
DNA Repair
/
DNA Breaks, Double-Stranded
/
DNA End-Joining Repair
Type of study:
Prognostic_studies
Limits:
Humans
Language:
En
Journal:
Leukemia
Journal subject:
HEMATOLOGIA
/
NEOPLASIAS
Year:
2015
Document type:
Article
Affiliation country:
Germany