The aflatoxin B1-fumonisin B1toxicity in BRL-3A hepatocytes is associated to induction of cytochrome P450 activity and arachidonic acid metabolism.
Human oral exposure to aflatoxin B1(AFB1) and fumonisin B1(FB1) is associated with increased hepatocellular carcinoma. Although evidence suggested interactive AFB1-FB1hepatotoxicity, the underlying mechanisms remain mostly unidentified. This work was aimed at evaluating the possible AFB1-FB1interplay to induce genetic and cell cycle toxicities in BRL-3A rat hepatocytes, reactive oxygen species (ROS) involvement, and the AFB1metabolizing pathways cytochrome P450 (CYP) and arachidonic acid (ArAc) metabolism as ROS contributors. Flow cytometry of stained BRL-3A hepatocytes was used to study the cell cycle (propidium iodide), ROS intracellular production (DCFH-DA, HE, DAF-2 DA), and phospholipase A activity (staining with bis-BODIPY FL C11-PC). The CYP1A activity was assessed by the 7-ethoxyresorufin-O-deethylase (EROD) assay. Despite a 48-h exposure to FB1(30 μM) not being genotoxic, the AFB1(20 μM)-induced micronucleus frequency was overcome by the AFB1-FB1mixture (MIX), presumably showing toxin interaction. The mycotoxins blocked G1/S-phase, but only MIX caused cell death. Overall, the oxidative stress led these alterations as the pretreatment with N-acetyl-l-cysteine reduced such toxic effects. While AFB1had a major input to the MIX pro-oxidant activity, with CYP and ArAc metabolism being ROS contributors, these pathways were not involved in the FB1-elicited weak oxidative stress. The MIX-induced micronucleus frequency in N-acetyl-l-cysteine pretreated cells was greater than that caused by AFB1without antioxidants, suggesting enhanced AFB1direct genotoxicity probably owing to the higher CYP activity and ArAc metabolism found in MIX. The metabolic pathways modulation by AFB1-FB1mixtures could raise its hepatocarcinogenic properties.
Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), UNC, CONICET, Córdoba, X5000HUA, Argentina.
Verónica S
VS
Mary
Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), UNC, CONICET, Córdoba, X5000HUA, Argentina.
Silvina L
SL
Arias
Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), UNC, CONICET, Córdoba, X5000HUA, Argentina.
Santiago N
SN
Otaiza
Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), UNC, CONICET, Córdoba, X5000HUA, Argentina.
Pilar A
PA
Velez
Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), UNC, CONICET, Córdoba, X5000HUA, Argentina.
Héctor R
HR
Rubinstein
Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Centro de Investigaciones en Bioquímica Clínica e Inmunología (CIBICI), UNC, CONICET, Córdoba, X5000HUA, Argentina.
Martín G
MG
Theumer
D000111:Acetylcysteine / Q000494:pharmacology; D016604:Aflatoxin B1 / Q000633:toxicity*; D000818:Animals; D001095:Arachidonic Acids / Q000378:metabolism*; D002453:Cell Cycle / Q000187:drug effects; D002460:Cell Line; D019363:Cytochrome P-450 CYP1A1 / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D004357:Drug Synergism; D037341:Fumonisins / Q000633:toxicity*; D022781:Hepatocytes / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D006801:Humans; D050356:Lipid Metabolism / Q000187:drug effects; D048629:Micronuclei, Chromosome-Defective / Q000139:chemically induced*; D009183:Mycotoxins / Q000633:toxicity; D018384:Oxidative Stress / Q000187:drug effects; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism
D001095:Arachidonic Acids; D037341:Fumonisins; D009183:Mycotoxins; D017382:Reactive Oxygen Species; C056933:fumonisin B1; D003577:Cytochrome P-450 Enzyme System; D016604:Aflatoxin B1; D019363:Cytochrome P-450 CYP1A1; D000111:Acetylcysteine
CYP1A; genotoxicity; mycotoxin mixture; oxidative stress; phospholipase A