title: Radio-sensitization of human leukaemic molt-4 cells by DNA-dependent protein kinase inhibitor, NU7026.
abstract: In this paper we describe the influence of NU7026, a specific inhibitor of DNA-dependent protein kinase, phosphoinositide 3-kinase, and ATM-kinase on molecular and cellular mechanisms triggered by ionising irradiation in human T-lymphocyte leukaemic MOLT-4 cells. We studied the effect of this inhibitor (10 1microM) combined with gamma-radiation (1 Gy) leading to DNA damage response and induction of apoptosis. We used methods for apoptosis assessment (cell viability count and flow-cytometric analysis) and cell cycle analysis (DNA content measurement) and we detected expression and post-translational modifications (Western blotting) of proteins involved in DNA repair signalling pathways. Pre-treatment with NU7026 resulted into decreased activation of checkpoint kinase-2 (Thr68), p53 (Ser15 and Ser392), and histone H2A.X (Ser139) 2 hours after irradiation. Subsequently, combination of radiation and inhibitor led to decreased amount of cells in G2-phase arrest and into increased apoptosis after 72 hours. Our results indicate that in leukaemic cells the pre-incubation with inhibitor NU7026 followed by low doses of ionising radiation results in radio-sensitising of MOLT-4 cells via diminished DNA repair and delayed but pronounced apoptosis. This novel approach might offer new strategies in combined treatment of leukaemia diseases.
authors.affiliation: Department of Radiobiology, University of Defence in Brno, Faculty of Health Sciences in Hradec Králové, Czech Republic. tichy@pmfhk.cz
authors.forename: Ales
authors.initials: A
authors.lastname: Tichý
authors.forename: Eva
authors.initials: E
authors.lastname: Novotná
authors.forename: Kamila
authors.initials: K
authors.lastname: Durisová
authors.forename: Barbora
authors.initials: B
authors.lastname: Salovská
authors.forename: Radka
authors.initials: R
authors.lastname: Sedlaríková
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Pejchal
authors.forename: Lenka
authors.initials: L
authors.lastname: Zárybnická
authors.forename: Jirina
authors.initials: J
authors.lastname: Vávrová
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Sinkorová
authors.forename: Martina
authors.initials: M
authors.lastname: Rezácová
mesh_terms: D017209:Apoptosis / Q000528:radiation effects; D002453:Cell Cycle / Q000528:radiation effects; D045744:Cell Line, Tumor / Q000528:radiation effects; D049109:Cell Proliferation / Q000528:radiation effects; D002867:Chromones / Q000494:pharmacology*; D004249:DNA Damage / Q000528:radiation effects; D004260:DNA Repair / Q000528:radiation effects; D051747:DNA-Activated Protein Kinase / Q000037:antagonists & inhibitors*; D005720:Gamma Rays; D006801:Humans; D015458:Leukemia, T-Cell / Q000532:radiotherapy*; D009025:Morpholines / Q000494:pharmacology*; D011836:Radiation Tolerance / Q000187:drug effects*; D011838:Radiation-Sensitizing Agents / Q000494:pharmacology*
chemical_list: C479235:2-(morpholin-4-yl)benzo(h)chromen-4-one; D002867:Chromones; D009025:Morpholines; D011838:Radiation-Sensitizing Agents; D051747:DNA-Activated Protein Kinase