title: Differential involvement of the hMRE11/hRAD50/NBS1 complex, BRCA1 and MLH1 in NF-kappaB activation by camptothecin and X-ray.
abstract: Camptothecin (CPT) and X-ray (XR) generate double-strand breaks (DSB) that can be processed by homologous or nonhomologous recombination. We studied the participation of proteins involved in recombination pathways and cell cycle control in the signal transduction between DNA damage and NF-kappaB. Cells harbouring mutated NBS, hMRE11, BRCA1 or MLH1 were analysed. NBS- and hMRE11-deficient cells present a classical kinetic of NF-kappaB induction after camptothecin treatment. When DSB are generated by XR, NBS-deficient cells exhibit a delayed and strongly reduced level of NF-kappaB induction, whereas the hMRE11 mutated cells do not induce NF-kappaB at all. This indicates an important role of the hMRE11/hRAD50/NBS complex in the signal transduction initiated by XR. In HCC1937 cells that express a truncated version of BRCA1, XR induces a very rapid and transient NF-kappaB activation, whereas CPT leads to a delayed activation suggesting that BRCA1 modulates the transduction pathways in different manners after these two stresses. Finally, we found that a proficient MMR pathway is essential to the NF-kappaB activation after both CPT and XR. These results indicate that DSB originating from XR or CPT do not induce NF-kappaB in a unique way. MMR participates in both cascades, whereas the hMRE11/hRAD50/NBS trimer is specifically involved in the response elicited by XR.
authors.affiliation: Laboratory of Virology and Immunology, Institute of Pathology B23, University de Liège, B-4000 Liège, Belgium. Yvette.Habraken@ulg.ac.be
authors.forename: Yvette
authors.initials: Y
authors.lastname: Habraken
authors.forename: Olivier
authors.initials: O
authors.lastname: Jolois
authors.forename: Jacques
authors.initials: J
authors.lastname: Piette
mesh_terms: D017766:Acid Anhydride Hydrolases; D048868:Adaptor Proteins, Signal Transducing; D019313:BRCA1 Protein / Q000187:drug effects / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D002166:Camptothecin / Q000494:pharmacology*; D002352:Carrier Proteins; D018797:Cell Cycle Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D004247:DNA / Q000187:drug effects / Q000528:radiation effects; D004249:DNA Damage / Q000502:physiology; D045643:DNA Repair Enzymes; D004268:DNA-Binding Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006367:HeLa Cells / Q000187:drug effects / Q000528:radiation effects; D006801:Humans; D000076228:MRE11 Homologue Protein; D046911:Macromolecular Substances; D000070957:MutL Protein Homolog 1; D009154:Mutation; D016328:NF-kappa B / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D009363:Neoplasm Proteins / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D009687:Nuclear Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D011839:Radiation, Ionizing; D015398:Signal Transduction; D014965:X-Rays
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D019313:BRCA1 Protein; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; C501486:MLH1 protein, human; C121766:MRE11 protein, human; D046911:Macromolecular Substances; C112156:NBN protein, human; D016328:NF-kappa B; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; C095888:xeroderma pigmentosum group F protein; D004247:DNA; D000076228:MRE11 Homologue Protein; D017766:Acid Anhydride Hydrolases; C112158:RAD50 protein, human; D000070957:MutL Protein Homolog 1; D045643:DNA Repair Enzymes; D002166:Camptothecin