TY - JOUR A1 - Pagáčová, Eva A1 - Štefančíková, Lenka A1 - Schmidt-Kaler, Franz A1 - Hildenbrand, Georg A1 - Vičar, Tomáš A1 - Depeš, Daniel A1 - Lee, Jin-Ho A1 - Bestvater, Felix A1 - Lacombe, Sandrine A1 - Porcel, Erika A1 - Roux, Stéphane A1 - Wenz, Frederik A1 - Kopecna, Olga A1 - Falková, Iva A1 - Hausmann, Michael A1 - Falk, Martin T1 - Challenges and Contradictions of Metal Nano-Particle Applications for Radio-Sensitivity Enhancement in Cancer Therapy JF - International Journal of Molecular Sciences N2 - From the very beginnings of radiotherapy, a crucial question persists with how to target the radiation effectiveness into the tumor while preserving surrounding tissues as undamaged as possible. One promising approach is to selectively pre-sensitize tumor cells by metallic nanoparticles. However, though the “physics” behind nanoparticle-mediated radio-interaction has been well elaborated, practical applications in medicine remain challenging and often disappointing because of limited knowledge on biological mechanisms leading to cell damage enhancement and eventually cell death. In the present study, we analyzed the influence of different nanoparticle materials (platinum (Pt), and gold (Au)), cancer cell types (HeLa, U87, and SKBr3), and doses (up to 4 Gy) of low-Linear Energy Transfer (LET) ionizing radiation (γ- and X-rays) on the extent, complexity and reparability of radiation-induced γH2AX + 53BP1 foci, the markers of double stand breaks (DSBs). Firstly, we sensitively compared the focus presence in nuclei during a long period of time post-irradiation (24 h) in spatially (three-dimensionally, 3D) fixed cells incubated and non-incubated with Pt nanoparticles by means of high-resolution immunofluorescence confocal microscopy. The data were compared with our preliminary results obtained for Au nanoparticles and recently published results for gadolinium (Gd) nanoparticles of approximately the same size (2–3 nm). Next, we introduced a novel super-resolution approach—single molecule localization microscopy (SMLM)—to study the internal structure of the repair foci. In these experiments, 10 nm Au nanoparticles were used that could be also visualized by SMLM. Altogether, the data show that different nanoparticles may or may not enhance radiation damage to DNA, so multi-parameter effects have to be considered to better interpret the radiosensitization. Based on these findings, we discussed on conclusions and contradictions related to the effectiveness and presumptive mechanisms of the cell radiosensitization by nanoparticles. We also demonstrate that SMLM offers new perspectives to study internal structures of repair foci with the goal to better evaluate potential differences in DNA damage patterns. KW - Krebs, Medizin KW - Strahlentherapie Y1 - 2019 U6 - https://doi.org/https://doi.org/10.3390/ijms20030588 SN - 1422-0067 VL - 20 IS - 3 PB - MDPI AG ER - TY - GEN A1 - Lee, Jin-Ho A1 - Bobkova, Elizaveta A1 - Gier, Theresa A1 - Gote, Martin A1 - Schmidt-kaler, Fanz A1 - Brieger, Emily A1 - Maus, Emanuel A1 - Krufczik, Matthias A1 - Chojowski, Robert A1 - Korn, Friederike A1 - Sarah, Schumann A1 - Scherthan, Harry A1 - Falkova, Iva A1 - Falk, Martin A1 - Hausmann, Michael A1 - Hildenbrand, Georg T1 - Mechanisms and Challenges for Understanding Radiation Induced Changes in Chromatin Nanoarchitecture T2 - DRO 2018 N2 - The three-dimensional architecture of genomes acts as an additional level of mode for fundamental biological processes such as DNA damage response. In this context, nanoprobing and super-resolution microscopy are powerful methods for structural analyses of genomic targets in native chromatin of single cells at resolutions of single antibodies, proteins, histones, short DNA stretches, etc. We used multi-color chromatin nanoprobing and single molecule localization microscopy of established DNA damage and chromatin markers in 3D-conserved nuclei of different cell types exposed to various types and doses of ionizing radiation. Similarly, effect of gold nanoparticles on extent and direction of cellular radiation response was assessed. Our studies revealed the nanoarchitecture of damage foci with respect to γH2AX, Mre11 or 53BP1 and their molecular rearrangements during repair processes. Nanoscopy of genomic Alu resulted in linear-quadratic dose-effects for low to higher dose ranges and in changes of H3K9me3 distribution around Alu clusters upon radiation exposure. Preliminary results show post-irradiation time dependent changes in Alu chromatin. Moreover, gold nanoparticles incorporated into cells seem to act by an interplay of radiation enhancement and chromatin remodeling leading to altered radiosensitivity. Our results contribute to the understanding of cellular radiation responses, thereby laying the basis for improved biological dosimetry and radiotherapies in future. N2 - Poster KW - Genom Y1 - 2019 U6 - https://doi.org/https://doi.org/10.13140/RG.2.2.31391.20647 ER -