title: Hypersensitivity of lymphoblastoid lines derived from ataxia telangiectasia patients to the induction of chromosomal aberrations by etoposide (VP-16).
abstract: Mammalian DNA topoisomerase II represents the cellular target of many antitumor drugs, such as epipodophyllotoxin VP-16 (etoposide). The mechanism by which VP-16 exerts its cytotoxic and antineoplastic actions has not yet been firmly established, although the unique correlation between sensitivity to ionizing radiation and to topoisomerase II inhibitors suggest the involvement of DNA double-strand breaks. In the present study we analyzed the chromosomal sensitivity of lymphoblastoid cell lines derived from ataxia telangiectasia (AT) patients to low concentrations of the drug. Our results indicate that AT derived cells are hypersensitive to the clastogenic activity of VP-16 either when the drug is present for the whole duration of the cell cycle or specifically in the G2 phase, confirming that the induction of DNA double strand breaks, to which AT cells seem typically sensitive, could have an important role in the biological activity of VP-16.
authors.affiliation: Department of Public Health and Cellular Biology, University of Tor Vergata, Rome, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Caporossi
authors.forename: B
authors.initials: B
authors.lastname: Porfirio
authors.forename: B
authors.initials: B
authors.lastname: Nicoletti
authors.forename: F
authors.initials: F
authors.lastname: Palitti
authors.forename: F
authors.initials: F
authors.lastname: Degrassi
authors.forename: R
authors.initials: R
authors.lastname: De Salvia
authors.forename: C
authors.initials: C
authors.lastname: Tanzarella
mesh_terms: D001260:Ataxia Telangiectasia / Q000235:genetics*; D002453:Cell Cycle / Q000187:drug effects*; D002460:Cell Line; D002869:Chromosome Aberrations; D004249:DNA Damage; D004261:DNA Replication / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005047:Etoposide / Q000494:pharmacology* / Q000633:toxicity; D005260:Female; D016195:G2 Phase / Q000187:drug effects; D006801:Humans; D008214:Lymphocytes / Q000187:drug effects; D008297:Male; D008940:Mitotic Index; D009153:Mutagens / Q000494:pharmacology*; D016196:S Phase / Q000187:drug effects
chemical_list: D009153:Mutagens; D005047:Etoposide