title: 7,12-Dimethylbenz(a)anthracene-induced genotoxicity on bone marrow cells from mice phenotypically selected for low acute inflammatory response.
abstract: Exposure to polycyclic aromatic hydrocarbon (PAH) environmental contaminants has been associated with the development of mutations and cancer. 7,12-Dimethylbenz(a)anthracene ( DMBA), a genotoxic agent, reacts with DNA directly, inducing p53-dependent cytotoxicity resulting in cell death by apoptosis or giving rise to cancer. DMBA metabolism largely depends on activation of the aryl hydrocarbon receptor (AhR). Mice phenotypically selected for high (AIRmax) or low (AIRmin) acute inflammatory response present a complete segregation of Ahr alleles endowed with low (Ahr(d)) or high (Ahr(b1)) affinity to PAHs, respectively. To evaluate the role of AhR genetic polymorphism on the bone marrow susceptibility to DMBA, AIRmax and AIRmin mice were treated with a single intraperitoneal injection of DMBA (50mg/kg b.w.) in olive oil. Bone marrow cells (BMCs) were phenotyped by both flow cytometry and cytoslide preparations. Despite a significant decrease in total cell count in BM from AIRmin mice, there was an increase of blast cells and immature neutrophils at 1 and 50 days after DMBA treatment, probably due to a cell-cycle blockade at the G1/S transition leading to immature stage cell production. A panel of proteins related to cell cycle regulation was evaluated in immature BM cells (Lin(-)) by Western Blot, and DNA damage and repair were measured using an alkaline version of the Comet assay. In Lin(-) cells isolated from AIRmin mice, high levels were found in both p53 and p21 protein contents in contrast with the low levels of CDK4 and Ciclin D1. Evaluation of DNA repair in DMBA-treated BMCs, indicated long-lasting genotoxicity and cytotoxicity in BMC from AIRmin mice and a blockade of cell cycle progression. On the other hand, AIRmax mice have a high capacity of DNA damage repair and protection. These mechanisms can be associated with the differential susceptibility to the toxic and carcinogenic effects of DMBA observed in these mice.
authors.affiliation: Immunogenetics Laboratory, Butantan Institute, São Paulo, Brazil.
authors.forename: Iana Suly Santos
authors.initials: IS
authors.lastname: Katz
authors.affiliation: Immunogenetics Laboratory, Butantan Institute, São Paulo, Brazil.
authors.forename: Layra Lucy
authors.initials: LL
authors.lastname: Albuquerque
authors.affiliation: Immunogenetics Laboratory, Butantan Institute, São Paulo, Brazil.
authors.forename: Alessandra Paes
authors.initials: AP
authors.lastname: Suppa
authors.affiliation: Laboratory of Experimental Hematology, Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil.
authors.forename: Graziela Batista
authors.initials: GB
authors.lastname: da Silva
authors.affiliation: Immunogenetics Laboratory, Butantan Institute, São Paulo, Brazil.
authors.forename: José Ricardo
authors.initials: JR
authors.lastname: Jensen
authors.affiliation: Immunogenetics Laboratory, Butantan Institute, São Paulo, Brazil.
authors.forename: Andrea
authors.initials: A
authors.lastname: Borrego
authors.affiliation: Immunogenetics Laboratory, Butantan Institute, São Paulo, Brazil.
authors.forename: Solange
authors.initials: S
authors.lastname: Massa
authors.affiliation: Immunogenetics Laboratory, Butantan Institute, São Paulo, Brazil.
authors.forename: Nancy
authors.initials: N
authors.lastname: Starobinas
authors.affiliation: Immunogenetics Laboratory, Butantan Institute, São Paulo, Brazil.
authors.forename: Wafa Hanna Koury
authors.initials: WH
authors.lastname: Cabrera
authors.affiliation: Immunogenetics Laboratory, Butantan Institute, São Paulo, Brazil.
authors.forename: Marcelo
authors.initials: M
authors.lastname: De Franco
authors.affiliation: Laboratory of Experimental Hematology, Department of Clinical and Toxicological Analyses, School of Pharmaceutical Sciences, University of São Paulo, São Paulo, Brazil.
authors.forename: Primavera
authors.initials: P
authors.lastname: Borelli
authors.affiliation: Immunogenetics Laboratory, Butantan Institute, São Paulo, Brazil.
authors.forename: Olga Martinez
authors.initials: OM
authors.lastname: Ibañez
authors.affiliation: Immunogenetics Laboratory, Butantan Institute, São Paulo, Brazil. Electronic address: orlando.ribeiro@butantan.gov.br.
authors.forename: Orlando Garcia
authors.initials: OG
authors.lastname: Ribeiro
mesh_terms: D015127:9,10-Dimethyl-1,2-benzanthracene / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics* / Q000378:metabolism; D001854:Bone Marrow Cells / Q000187:drug effects*; D020552:Comet Assay; D004247:DNA / Q000187:drug effects; D004249:DNA Damage; D004260:DNA Repair / Q000235:genetics; D004785:Environmental Pollutants / Q000633:toxicity*; D005434:Flow Cytometry; D007249:Inflammation / Q000235:genetics; D008297:Male; D051379:Mice; D009153:Mutagens / Q000633:toxicity*; D011110:Polymorphism, Genetic; D018336:Receptors, Aryl Hydrocarbon / Q000235:genetics* / Q000378:metabolism
chemical_list: D015127:9,10-Dimethyl-1,2-benzanthracene; D051792:Basic Helix-Loop-Helix Proteins; D004247:DNA; D004785:Environmental Pollutants; D009153:Mutagens; D018336:Receptors, Aryl Hydrocarbon; C484722:Ahr protein, mouse
keywords: Acute inflammatory response; Bone Marrow; DMBA; DMBA toxicity