title: BRCA1, FANCD2 and Chk1 are potential molecular targets for the modulation of a radiation-induced DNA damage response in bystander cells.
abstract: Radiotherapy is an important treatment option for many human cancers. Current research is investigating the use of molecular targeted drugs in order to improve responses to radiotherapy in various cancers. The cellular response to irradiation is driven by both direct DNA damage in the targeted cell and intercellular signalling leading to a broad range of bystander effects. This study aims to elucidate radiation-induced DNA damage response signalling in bystander cells and to identify potential molecular targets to modulate the radiation induced bystander response in a therapeutic setting. Stalled replication forks in T98G bystander cells were visualised via bromodeoxyuridine (BrdU) nuclear foci detection at sites of single stranded DNA. γH2AX co-localised with these BrdU foci. BRCA1 and FANCD2 foci formed in T98G bystander cells. Using ATR mutant F02-98 hTERT and ATM deficient GM05849 fibroblasts it could be shown that ATR but not ATM was required for the recruitment of FANCD2 to sites of replication associated DNA damage in bystander cells whereas BRCA1 bystander foci were ATM-dependent. Phospho-Chk1 foci formation was observed in T98G bystander cells. Clonogenic survival assays showed moderate radiosensitisation of directly irradiated cells by the Chk1 inhibitor UCN-01 but increased radioresistance of bystander cells. This study identifies BRCA1, FANCD2 and Chk1 as potential targets for the modulation of radiation response in bystander cells. It adds to our understanding of the key molecular events propagating out-of-field effects of radiation and provides a rationale for the development of novel molecular targeted drugs for radiotherapy optimisation.
authors.affiliation: Centre for Cancer Research and Cell Biology, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK. Electronic address: s.burdakrothkamm@yahoo.co.uk.
authors.forename: Susanne
authors.initials: S
authors.lastname: Burdak-Rothkamm
authors.affiliation: Public Health England, Centre for Radiation, Chemical and Environmental Hazards, Chilton/Didcot OX11 0RQ, UK.
authors.forename: Kai
authors.initials: K
authors.lastname: Rothkamm
authors.affiliation: Centre for Cancer Research and Cell Biology, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK.
authors.forename: Keeva
authors.initials: K
authors.lastname: McClelland
authors.affiliation: Centre for Cancer Research and Cell Biology, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK.
authors.forename: Shahnaz T
authors.initials: ST
authors.lastname: Al Rashid
authors.affiliation: Centre for Cancer Research and Cell Biology, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, UK.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Prise
mesh_terms: D064007:Ataxia Telangiectasia Mutated Proteins / Q000235:genetics; D019313:BRCA1 Protein / Q000378:metabolism*; D015153:Blotting, Western; D001932:Brain Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology* / Q000532:radiotherapy; D024201:Bystander Effect / Q000235:genetics* / Q000528:radiation effects; D049109:Cell Proliferation / Q000528:radiation effects; D000071877:Checkpoint Kinase 1; D004249:DNA Damage / Q000235:genetics* / Q000528:radiation effects; D004260:DNA Repair / Q000235:genetics / Q000528:radiation effects; D004261:DNA Replication / Q000235:genetics / Q000528:radiation effects; D052236:Fanconi Anemia Complementation Group D2 Protein / Q000378:metabolism*; D005434:Flow Cytometry; D005910:Glioma / Q000235:genetics / Q000378:metabolism / Q000473:pathology* / Q000532:radiotherapy; D006801:Humans; D007124:Immunoenzyme Techniques; D009154:Mutation / Q000235:genetics; D010766:Phosphorylation / Q000528:radiation effects; D011494:Protein Kinases / Q000378:metabolism*; D015398:Signal Transduction / Q000528:radiation effects; D014407:Tumor Cells, Cultured; D014965:X-Rays
chemical_list: D019313:BRCA1 Protein; C492913:BRCA1 protein, human; C499905:FANCD2 protein, human; D052236:Fanconi Anemia Complementation Group D2 Protein; D011494:Protein Kinases; C576324:ATM protein, human; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; C000605867:CHEK1 protein, human; D000071877:Checkpoint Kinase 1
keywords: BRCA; DNA damage response; Fanconi anaemia; Ionising radiation; Radiation-induced bystander effect