title: Hydroxyurea induces chromosomal damage in G2 and enhances the clastogenic effect of mitomycin C in Fanconi anemia cells.
abstract: Fanconi's anemia (FA) is a recessive disease; 16 genes are currently recognized in FA. FA proteins participate in the FA/BRCA pathway that plays a crucial role in the repair of DNA damage induced by crosslinking compounds. Hydroxyurea (HU) is an agent that induces replicative stress by inhibiting ribonucleotide reductase (RNR), which synthesizes deoxyribonucleotide triphosphates (dNTPs) necessary for DNA replication and repair. HU is known to activate the FA pathway; however, its clastogenic effects are not well characterized. We have investigated the effects of HU treatment alone or in sequential combination with mitomycin-C (MMC) on FA patient-derived lymphoblastoid cell lines from groups FA-A, B, C, D1/BRCA2, and E and on lymphocytes from two unclassified FA patients. All FA cells showed a significant increase (P < 0.05) in chromosomal aberrations following treatment with HU during the last 3 h before mitosis. Furthermore, when FA cells previously exposed to MMC were treated with HU, we observed an increase of MMC-induced DNA damage that was characterized by high occurrence of DNA breaks and a reduction in rejoined chromosomal aberrations. These findings show that exposure to HU during G2 induces chromosomal aberrations by a mechanism that is independent of its well-known role in replication fork stalling during S-phase and that HU interfered mainly with the rejoining process of DNA damage. We suggest that impaired oxidative stress response, lack of an adequate amount of dNTPs for DNA repair due to RNR inhibition, and interference with cell cycle control checkpoints underlie the clastogenic activity of HU in FA cells. Environ. Mol. Mutagen. 56:457-467, 2015. © 2015 Wiley Periodicals, Inc.
authors: Laboratorio de Citogenética, Instituto Nacional de Pediatría, México.
authors: Bertha
authors: B
authors: Molina
authors: Lawrence Berkeley National Laboratory, Berkeley, California.
authors: Francesco
authors: F
authors: Marchetti
authors: Laboratorio de Citogenética, Instituto Nacional de Pediatría, México.
authors: Laura
authors: L
authors: Gómez
authors: Laboratorio de Citogenética, Instituto Nacional de Pediatría, México.
authors: Sandra
authors: S
authors: Ramos
authors: Laboratorio de Citogenética, Instituto Nacional de Pediatría, México.
authors: Leda
authors: L
authors: Torres
authors: Laboratorio de Citometría de Flujo, Universidad Autónoma Metropolitana, Iztapalapa, Mexico.
authors: Rocio
authors: R
authors: Ortiz
authors: Unidad de Investigación en Genética y Toxicología (UNIGEN), FES-Zaragoza, UNAM, México.
authors: Mario
authors: M
authors: Altamirano-Lozano
authors: Subdirección de Genómica Poblacional, Instituto Nacional de Medicina Genómica, México.
authors: Alessandra
authors: A
authors: Carnevale
authors: Laboratorio de Citogenética, Instituto Nacional de Pediatría, México.|Departamento de Medicina, Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, UNAM, México.
authors: Sara
authors: S
authors: Frias
mesh_terms: D002460:Cell Line; D002869:Chromosome Aberrations / Q000139:chemically induced*; D020732:Cytogenetic Analysis; D004357:Drug Synergism; D005199:Fanconi Anemia / Q000097:blood* / Q000235:genetics; D016195:G2 Phase / Q000187:drug effects* / Q000235:genetics; D064368:Healthy Volunteers; D006801:Humans; D006918:Hydroxyurea / Q000633:toxicity*; D008214:Lymphocytes / Q000187:drug effects* / Q000473:pathology; D016685:Mitomycin / Q000633:toxicity*; D009153:Mutagens / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects / Q000235:genetics
chemical_list: D009153:Mutagens; D016685:Mitomycin; D006918:Hydroxyurea
keywords: DNA repair; chromosomal aberrations; double strand breaks; ribonucleotide reductase