title: Effect of poly(ADP-ribosyl)ation inhibitors on the genotoxic effects of the boron neutron capture reaction.
abstract: The boron neutron capture (BNC) reaction results from the interaction of 10B with low-energy thermal neutrons and gives rise to highly damaging lithium and alpha-particles. In this work the genotoxicity caused by the BNC reaction in V79 Chinese hamster cells was evaluated in the presence of poly(ADP-ribosyl)ation inhibitors. Poly(ADP-ribose) polymerase-1 (PARP-1), the most important member of the PARP enzyme family, is considered to be a constitutive factor of the DNA damage surveillance network present in eukaryotic cells, acting through a DNA break sensor function. Inhibition of poly(ADP-ribosyl)ation was achieved with the classical compound 3-aminobenzamide (3-AB), and with two novel and very potent inhibitors, 5-aminoisoquinolinone (5-AIQ) and PJ-34. Dose-response increases in the frequencies of aberrant cells excluding gaps (%ACEG) and chromosomal aberrations excluding gaps per cell (CAEG/cell) were observed for increasing exposures to the BNC reaction. The presence of 3-AB did not increase the %ACEG or CAEG/cell, nor did it change the pattern of the induced chromosomal aberrations. Results with 5-AIQ and PJ-34 were in agreement with the results obtained with 3-AB. We further studied the combined effect of a PARP inhibitor and a DNA-dependent protein kinase (DNA-PK) inhibitors (3-AB and wortmannin, respectively) on the genotoxicity of the BNC reaction, by use of the cytokinesis-block micronucleus assay. DNA-PK is also activated by DNA breaks and binds DNA ends, playing a role of utmost importance in the repair of double-strand breaks. Our results show that the inhibition of poly(ADP-ribosyl)ation does not particularly modify the genotoxicity of the BNC reaction, and that PARP inhibition together with a concomitant inhibition of DNA-PK revealed barely the same sensitizing effect as DNA-PK inhibition per se.
authors.affiliation: Department of Genetics, Faculty of Medical Sciences, New University of Lisbon, R. da Junqueira 96, P 1349-008 Lisbon, Portugal.
authors.forename: Nuno G
authors.initials: NG
authors.lastname: Oliveira
authors.forename: Matilde
authors.initials: M
authors.lastname: Castro
authors.forename: António S
authors.initials: AS
authors.lastname: Rodrigues
authors.forename: Isabel C
authors.initials: IC
authors.lastname: Gonçalves
authors.forename: Célia
authors.initials: C
authors.lastname: Martins
authors.forename: José M
authors.initials: JM
authors.lastname: Toscano Rico
authors.forename: José
authors.initials: J
authors.lastname: Rueff
mesh_terms: D000512:Alpha Particles; D000818:Animals; D016754:Boron Neutron Capture Therapy / Q000009:adverse effects*; D018929:Cell Culture Techniques; D006224:Cricetinae; D003412:Cricetulus; D004249:DNA Damage; D051747:DNA-Activated Protein Kinase; D004268:DNA-Binding Proteins / Q000494:pharmacology; D005347:Fibroblasts; D006801:Humans; D009152:Mutagenicity Tests; D009687:Nuclear Proteins; D000071137:Poly (ADP-Ribose) Polymerase-1; D011064:Poly Adenosine Diphosphate Ribose / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D011065:Poly(ADP-ribose) Polymerases / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000494:pharmacology
chemical_list: D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D011064:Poly Adenosine Diphosphate Ribose; C499320:PARP1 protein, human; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; D051747:DNA-Activated Protein Kinase; C497263:PRKDC protein, human; D017346:Protein Serine-Threonine Kinases