1. LABORATORY OF RADIATION BIOLOGY Radiaton Induced Apoptosis in Human Lymphocytes Joint Institute for Nuclear Research Karolina Ficenzova, Martin Sefl Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague JINR Summer Practice 2010, Dubna

2. Damage of DNA direct indirect – high energy particle lyse the water and free radicals results (H 3 0 +, OH - ·, HO 2 · )

3. DNA damages Single-strand break Double strand break Base damage Sugar damage Laboratory of Radiation Biology, JINR

4. Apoptosis (programmed cell death)  Apoptosis is an important mechanism which provides the removal of weakened, unnecessary, and damaged cells.  Apoptosis is necessary for maintaining the stability of genetic information.  The loss of the spontaneous apoptosis capability results in carcinogenesis.  Apoptosis efficiency is strongly decreased or completely suppressed in cancer cells. Laboratory of Radiation Biology, JINR

6. 6 Donors blood Incubations of the cells for 24, 48, 72 h Lymphocytes separation Irradiation Phasotron Rocus-M detecting with a fluorescent microscope preparations Laboratory of Radiation Biology, JINR

7. Imaging different forms of cell death Living cells and death cells (thanks to apoptosis or necrosis) were detected with a fluorescent microscope by tracing morphological changes in preparations stained with a mix of dyes – ethidium bromide and acridine orange. necrosisliving apoptosis Laboratory of Radiation Biology, JINR

8. Apoptotic cell yield 0, 24 and 48 h after irradiation  -rays Protons Laboratory of Radiation Biology, JINR

9. Influence of DNA repairinhibitors on the induction of DNA lesions Influence of DNA repair inhibitors on the induction of DNA lesions AraC+Hu S 1 endonuclease Double-strand break After γ -irradiation, some difficult-to- repair single-strand DNA breaks (SSB) formed in cells. When Ara-C and Hu were applied, these lesions – unrepaired for a long time – were attacked by S1-endonuclease, which attacked the opposite SSB site turning them into DNA double- strand breaks. As a result, the post- period apoptotic cell output increased. Laboratory of Radiation Biology, JINR

10. Apoptotic cell output after γ-irradiation with DNA repair inhibitors Ara-C and Hu Laboratory of Radiation Biology, JINR

11. Influence of DNA repair inhibitors Ara-C and Hu on proton-induced apoptosis Laboratory of Radiation Biology, JINR

12. Thank you for attention! Laboratory of Radiation Biology, JINR