title: Characterization of glioma stem cells through multiple stem cell markers and their specific sensitization to double-strand break-inducing agents by pharmacological inhibition of ataxia telangiectasia mutated protein.
abstract: Previous studies have shown that tumor-driving glioma stem cells (GSC) may promote radio-resistance by constitutive activation of the DNA damage response started by the ataxia telangiectasia mutated (ATM) protein. We have investigated whether GSC may be specifically sensitized to ionizing radiation by inhibiting the DNA damage response. Two grade IV glioma cell lines (BORRU and DR177) were characterized for a number of immunocytochemical, karyotypic, proliferative and differentiative parameters. In particular, the expression of a panel of nine stem cell markers was quantified by reverse transcription-polymerase chain reaction (RT-PCR) and flow cytometry. Overall, BORRU and DR177 displayed pronounced and poor stem phenotypes, respectively. In order to improve the therapeutic efficacy of radiation on GSC, the cells were preincubated with a nontoxic concentration of the ATM inhibitors KU-55933 and KU-60019 and then irradiated. BORRU cells were sensitized to radiation and radio-mimetic chemicals by ATM inhibitors whereas DR177 were protected under the same conditions. No sensitization was observed after cell differentiation or to drugs unable to induce double-strand breaks (DSB), indicating that ATM inhibitors specifically sensitize glioma cells possessing stem phenotype to DSB-inducing agents. In conclusion, pharmacological inhibition of ATM may specifically sensitize GSC to DSB-inducing agents while sparing nonstem cells.
authors.affiliation: Neurosurgery Unit, Istituto Giannina Gaslini, Genova, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Raso
authors.forename: Donatella
authors.initials: D
authors.lastname: Vecchio
authors.forename: Enrico
authors.initials: E
authors.lastname: Cappelli
authors.forename: Monica
authors.initials: M
authors.lastname: Ropolo
authors.forename: Alessandro
authors.initials: A
authors.lastname: Poggi
authors.forename: Paolo
authors.initials: P
authors.lastname: Nozza
authors.forename: Roberto
authors.initials: R
authors.lastname: Biassoni
authors.forename: Samantha
authors.initials: S
authors.lastname: Mascelli
authors.forename: Valeria
authors.initials: V
authors.lastname: Capra
authors.forename: Fotios
authors.initials: F
authors.lastname: Kalfas
authors.forename: Paolo
authors.initials: P
authors.lastname: Severi
authors.forename: Guido
authors.initials: G
authors.lastname: Frosina
mesh_terms: D001260:Ataxia Telangiectasia / Q000235:genetics* / Q000378:metabolism*; D045744:Cell Line, Tumor; D053903:DNA Breaks, Double-Stranded; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000494:pharmacology; D005346:Fibroblast Growth Factors / Q000494:pharmacology; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects / Q000235:genetics* / Q000528:radiation effects; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006801:Humans; D007381:Intermediate Filament Proteins / Q000378:metabolism; D007621:Karyotyping; D009154:Mutation / Q000235:genetics; D014411:Neoplastic Stem Cells / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D009419:Nerve Tissue Proteins / Q000378:metabolism; D064231:Nestin; D009447:Neuroblastoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D011839:Radiation, Ionizing
chemical_list: D004791:Enzyme Inhibitors; D005904:Glial Fibrillary Acidic Protein; D007381:Intermediate Filament Proteins; C577484:NES protein, human; D009419:Nerve Tissue Proteins; D064231:Nestin; D005346:Fibroblast Growth Factors; D004815:Epidermal Growth Factor