title: Imaging of nuclear factor κB activation induced by ionizing radiation in human embryonic kidney (HEK) cells.
abstract: Ionizing radiation modulates several signaling pathways resulting in transcription factor activation. Nuclear factor kappa B (NF-κB) is one of the most important transcription factors that respond to changes in the environment of a mammalian cell. NF-κB plays a key role not only in inflammation and immune regulation but also in cellular radiation response. In response to DNA damage, NF-κB might inhibit apoptosis and promote carcinogenesis. Our previous studies showed that ionizing radiation is very effective in inducing biological damages. Therefore, it is important to understand the radiation-induced NF-κB signaling cascade. The current study aims to improve existing mammalian cell-based reporter assays for NF-κB activation by the use of DD-tdTomato which is a destabilized variant of red fluorescent protein tdTomato. It is demonstrated that exposure of recombinant human embryonic kidney cells (HEK/293 transfected with a reporter constructs containing NF-κB binding sites in its promoter) to ionizing radiation induces NF-κB-dependent DD-tdTomato expression. Using this reporter assays, NF-κB signaling in mammalian cells was monitored by flow cytometry and fluorescence microscopy. Activation of NF-κB by the canonical pathway was found to be quicker than by the genotoxin- and stress-induced pathway. X-rays activate NF-κB in HEK cells in a dose-dependent manner, and the extent of NF-κB activation is higher as compared to camptothecin.
authors.affiliation: Radiation Biology, Institute of Aerospace Medicine, German Aerospace Centre (DLR), Linder Höhe, 51147, Köln, Germany, arif.chishti@dlr.de.
authors.forename: Arif Ali
authors.initials: AA
authors.lastname: Chishti
authors.forename: Christa
authors.initials: C
authors.lastname: Baumstark-Khan
authors.forename: Christine E
authors.initials: CE
authors.lastname: Hellweg
authors.forename: Günther
authors.initials: G
authors.lastname: Reitz
mesh_terms: D049109:Cell Proliferation / Q000528:radiation effects; D004249:DNA Damage; D004307:Dose-Response Relationship, Radiation; D005786:Gene Expression Regulation / Q000528:radiation effects; D057809:HEK293 Cells; D006801:Humans; D008164:Luminescent Proteins / Q000378:metabolism; D057054:Molecular Imaging; D016328:NF-kappa B / Q000378:metabolism*; D014965:X-Rays
chemical_list: D008164:Luminescent Proteins; D016328:NF-kappa B