title: Glioma-amplified sequence KUB3 influences double-strand break repair after ionizing radiation.
abstract: Human glioblastomas are characterized by frequent DNA amplifications most often at chromosome regions 7p11.2 and 12q13-15. Although amplification is a well-known hallmark of glioblastoma genetics the function of most amplified genes in glioblastoma biology is not understood. Previously, we cloned Ku70-binding protein 3 (KUB3) from the amplified domain at 12q13-15. Here, we report that glioblastoma cell cultures with endogenous KUB3 gene amplification and with elevated KUB3 protein expression show an efficient double-strand break (DSB) repair after being irradiated with 1 Gy. A significantly less efficient DSB repair was found in glioma cell cultures without KUB3 amplification and expression. Furthermore, we found that a siRNA-mediated reduction of the endogenous KUB3 expression in glioblastoma cells resulted in a reduction of the repair efficiency. HeLa cells transfected with KUB3 showed an increased DSB repair in comparison to untreated HeLa cells. In addition, KUB3 seems to influence DSB efficiency via the DNA-PK-dependent repair pathway as shown by simultaneous inhibition of KUB3 and DNA-PK. The data provide the first evidence for a link between the level of KUB3 amplification and expression in glioma and DSB repair efficiency.
authors.affiliation: Department of Human Genetics, Medical School, Saarland University, D-66421 Homburg/Saar, Germany. ulrike.fischer@uks.eu
authors.forename: Ulrike
authors.initials: U
authors.lastname: Fischer
authors.forename: Stefanie
authors.initials: S
authors.lastname: Rheinheimer
authors.forename: Andrea
authors.initials: A
authors.lastname: Krempler
authors.forename: Markus
authors.initials: M
authors.lastname: Löbrich
authors.forename: Eckart
authors.initials: E
authors.lastname: Meese
mesh_terms: D034961:Antigens, Nuclear / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics*; D053903:DNA Breaks, Double-Stranded / Q000528:radiation effects*; D004260:DNA Repair / Q000528:radiation effects*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005784:Gene Amplification / Q000528:radiation effects; D015972:Gene Expression Regulation, Neoplastic / Q000528:radiation effects; D005910:Glioma / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D006367:HeLa Cells; D006801:Humans; D000072200:Ku Autoantigen; D011485:Protein Binding / Q000528:radiation effects; D034741:RNA, Small Interfering; D011839:Radiation, Ionizing
chemical_list: C585461:ATP23 protein, human; D034961:Antigens, Nuclear; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D034741:RNA, Small Interfering; C000606509:Xrcc6 protein, human; D000072200:Ku Autoantigen