title: Near-infrared exposure changes cellular responses to ionizing radiation.
abstract: Near infrared (NIR) and X-rays are radiations from different sides of the wavelength spectrum but both are used during medical treatments, as they have severe impacts on cellular processes, including metabolism, gene expression, proliferation and survival. However, both radiations differ strictly in their consequences for exposed patients: NIR effects are generally supposed to be positive, mostly ascribed to a stimulation of metabolism, whereas X-ray leads to genetic instability, an increase of reactive oxygen species (ROS) and DNA damages and finally to cellular death by apoptosis in tumor cells. Since genomic stability after X-irradiation depends on the mitochondrial metabolism, which is well known to be regulated by NIR, we analyzed the impact of NIR on cellular responses of fibroblasts, retinal progenitor cells and keratinocytes to X-radiation. Our data show that previous exposure to naturally occurring doses of nonthermal NIR combined with clinically relevant X-ray doses leads to (1) increased genomic instability, indicated by elevated ratios of mitotic catastrophes, (2) increased ROS, (3) higher amounts of X-irradiated cells entering S-phase and (4) impaired DNA double-strand break repair. Taken together, our data show tremendous effects of NIR on cellular responses to X-rays, probably affecting the results of radiotherapy after NIR exposure during cancer treatment.
authors: Developmental Biology and Neurogenetics, TU Darmstadt, Darmstadt, Germany. heselich@bio.tu-darmstadt.de
authors: Anja
authors: A
authors: Heselich
authors: Florian
authors: F
authors: Frohns
authors: Antonia
authors: A
authors: Frohns
authors: Steffen C
authors: SC
authors: Naumann
authors: Paul G
authors: PG
authors: Layer
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000528:radiation effects; D001483:Base Sequence; D017931:DNA Primers; D006801:Humans; D051379:Mice; D041681:NIH 3T3 Cells; D009369:Neoplasms / Q000473:pathology; D016133:Polymerase Chain Reaction; D011839:Radiation, Ionizing
chemical_list: D017931:DNA Primers