title: Fanconi anemia is characterized by delayed repair kinetics of DNA double-strand breaks.
abstract: Among patients with bone marrow failure (BMF) syndrome, some are happened to have underlying Fanconi anemia (FA), a genetically heterogeneous disease, which is characterized by progressive pancytopenia and cancer susceptibility. Due to heterogeneous nature of the disease, a single genetic test, as in vitro response to DNA cross-linking agents, usually is not enough to make correct diagnosis. The aim of this study was to evaluate whether measuring repair kinetics of radiation-induced DNA double-strand breaks (DSBs) can distinguish Fanconi anemia from other BMF patients. An early step in repair of DSBs is phosphorylation of the histone H2AX, generating gamma-H2AX histone, which extends over mega base-pair regions of DNA from the break site and is visualised as foci (gamma-H2AX foci) with specific antibodies. The primary fibroblasts, established from FA patients, were exposed to gamma-rays, a dose of 2 Gy ((60)Co), incubated for up to 24 hours under repair-permissive conditions, and assayed for the level of gamma-H2AX foci and apoptosis at different recovery times after the treatment. Cell lines originating from FA patients displayed a significant delay in the repair of radiation-induced DNA DSBs relative to non-FA bone marrow failure (non-FA BMF) and control cell lines. The delay is especially evident at recovery time of 24 hours, and is seen as about 8-fold increase of residual gamma-H2AX foci compared to self-state before irradiation. The delay in repair kinetics of FA cells represents the unique feature of FA cellular phenotype, which should be exploited to distinguish FA cellular phenotype.
authors.affiliation: Vinca Institute of Nuclear Sciences, Belgrade, Serbia.
authors.forename: Andreja
authors.initials: A
authors.lastname: Leskovac
authors.forename: Dragana
authors.initials: D
authors.lastname: Vujic
authors.forename: Marija
authors.initials: M
authors.lastname: Guc-Scekic
authors.forename: Sandra
authors.initials: S
authors.lastname: Petrovic
authors.forename: Ivana
authors.initials: I
authors.lastname: Joksic
authors.forename: Predrag
authors.initials: P
authors.lastname: Slijepcevic
authors.forename: Gordana
authors.initials: G
authors.lastname: Joksic
mesh_terms: D000293:Adolescent; D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D003432:Cross-Linking Reagents / Q000494:pharmacology; D053903:DNA Breaks, Double-Stranded / Q000187:drug effects / Q000528:radiation effects; D004260:DNA Repair / Q000187:drug effects / Q000528:radiation effects; D003937:Diagnosis, Differential; D004852:Epoxy Compounds / Q000494:pharmacology; D005199:Fanconi Anemia / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D005260:Female; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology / Q000528:radiation effects; D019084:Fluorescent Antibody Technique, Indirect; D006657:Histones / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008297:Male; D009190:Myelodysplastic Syndromes / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D011237:Predictive Value of Tests
chemical_list: D003432:Cross-Linking Reagents; D004852:Epoxy Compounds; C468783:H2AX protein, human; D006657:Histones; C007366:diepoxybutane