title: Overexpression of the ∆Np73 isoform is associated with centrosome amplification in brain tumor cell lines.
abstract: The p73 protein is a member of the p53 family, and this protein is known to be essential for the maintenance of genomic stability, DNA repair, and apoptosis regulation. Transcription from two promoters leads to two main N-terminal isoforms: the TAp73 isoform is reported to have tumor suppressor function, whereas the ΔNp73 isoform likely has oncogenic potential. The present study is focused on the investigation of a possible role of both these p73 N-terminal isoforms in the process of centrosome amplification. HGG-02 and GM7 glioblastoma cell lines and the Daoy medulloblastoma cell line were used in this study. The cells were analyzed using indirect immunofluorescence to determine TAp73 and ΔNp73 expression patterns and possible co-localization with the BubR1 protein, as well as the number of centrosomes. A transiently transfected GM7 cell line was used to verify the results concerning the N-terminal isoforms in relation to centrosome amplification. We found that increased immunoreactivity for the ΔNp73 isoform is associated with the occurrence of an abnormal number of centrosomes in particular cells. Using the transiently transfected GM7 cell line, we confirmed that centrosome amplification is present in cells with overexpression of the ΔNp73 isoform. In contrast, the immunoreactivity for the TAp73 isoform was weak or medium in most of the cells with an aberrant number of centrosomes. To determine the putative counterpart of the p73 N-terminal isoforms among spindle assembly checkpoint (SAC) proteins, we also evaluated possible interactions between the N-terminal isoforms and BubR1 protein, but no co-localization of these proteins was observed.
authors.affiliation: Laboratory of Tumor Biology, Department of Experimental Biology, School of Science, Masaryk University, Kotlarska 2, 611 37, Brno, Czech Republic.
authors.forename: Erika
authors.initials: E
authors.lastname: Mikulenkova
authors.affiliation: Laboratory of Tumor Biology, Department of Experimental Biology, School of Science, Masaryk University, Kotlarska 2, 611 37, Brno, Czech Republic.|Regional Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, Zluty kopec 7, 656 53, Brno, Czech Republic.
authors.forename: Jakub
authors.initials: J
authors.lastname: Neradil
authors.affiliation: Laboratory of Tumor Biology, Department of Experimental Biology, School of Science, Masaryk University, Kotlarska 2, 611 37, Brno, Czech Republic.|Department of Pediatric Oncology, University Hospital Brno and School of Medicine, Masaryk University, Cernopolni 9, 613 00, Brno, Czech Republic.|Regional Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, Zluty kopec 7, 656 53, Brno, Czech Republic.
authors.forename: Karel
authors.initials: K
authors.lastname: Zitterbart
authors.affiliation: Department of Pediatric Oncology, University Hospital Brno and School of Medicine, Masaryk University, Cernopolni 9, 613 00, Brno, Czech Republic.|Regional Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, Zluty kopec 7, 656 53, Brno, Czech Republic.
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Sterba
authors.affiliation: Laboratory of Tumor Biology, Department of Experimental Biology, School of Science, Masaryk University, Kotlarska 2, 611 37, Brno, Czech Republic. veselska@sci.muni.cz.|Department of Pediatric Oncology, University Hospital Brno and School of Medicine, Masaryk University, Cernopolni 9, 613 00, Brno, Czech Republic. veselska@sci.muni.cz.
authors.forename: Renata
authors.initials: R
authors.lastname: Veselska
mesh_terms: D001932:Brain Neoplasms / Q000235:genetics* / Q000473:pathology*; D018385:Centrosome / Q000502:physiology*; D002869:Chromosome Aberrations; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000235:genetics*; D019084:Fluorescent Antibody Technique, Indirect; D005784:Gene Amplification; D006801:Humans; D009687:Nuclear Proteins / Q000235:genetics*; D011401:Promoter Regions, Genetic; D020033:Protein Isoforms; D017346:Protein Serine-Threonine Kinases / Q000235:genetics; D014407:Tumor Cells, Cultured; D000072160:Tumor Protein p73; D025521:Tumor Suppressor Proteins / Q000235:genetics*
chemical_list: D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D020033:Protein Isoforms; C000606460:TP73 protein, human; D000072160:Tumor Protein p73; D025521:Tumor Suppressor Proteins; C000606369:delta Np73 protein, human; C584277:BUB1 protein, human; D017346:Protein Serine-Threonine Kinases
keywords: BubR1; Centrosome amplification; Glioblastoma multiforme; Medulloblastoma; TAp73; ΔNp73