The aflatoxin B1‐fumonisin B1 toxicity 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–FB1 hepatotoxicity, the underlying mechanisms remain mostly unidentified. This work was aimed at evaluating the possible AFB1–FB1 inte...

Full description

Saved in:
Bibliographic Details
Published in:Environmental toxicology 2017-06, Vol.32 (6), p.1711-1724
Main Authors: Mary, Verónica S., Arias, Silvina L., Otaiza, Santiago N., Velez, Pilar A., Rubinstein, Héctor R., Theumer, Martín G.
Format: Article
Language:English
Subjects:
Acetylcysteine
Aflatoxin B1
Antioxidants
Arachidonic acid
Cell cycle
Cell death
CYP1A
CYP1A protein
Cysteine
Cytochrome
Cytochrome P450
Cytometry
Exposure
Flow cytometry
Fumonisin B1
Genotoxicity
Hepatocellular carcinoma
Hepatocytes
Hepatotoxicity
Metabolic pathways
Metabolism
mycotoxin mixture
Mycotoxins
Oxidative stress
Phospholipase
Phospholipase A
Pretreatment
Propidium iodide
Reactive oxygen species
Staining
Toxicity
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Human oral exposure to aflatoxin B1 (AFB1) and fumonisin B1 (FB1) is associated with increased hepatocellular carcinoma. Although evidence suggested interactive AFB1–FB1 hepatotoxicity, the underlying mechanisms remain mostly unidentified. This work was aimed at evaluating the possible AFB1–FB1 interplay to induce genetic and cell cycle toxicities in BRL‐3A rat hepatocytes, reactive oxygen species (ROS) involvement, and the AFB1 metabolizing 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–FB1 mixture (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 AFB1 had 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 AFB1 without antioxidants, suggesting enhanced AFB1 direct genotoxicity probably owing to the higher CYP activity and ArAc metabolism found in MIX. The metabolic pathways modulation by AFB1–FB1 mixtures could raise its hepatocarcinogenic properties.
ISSN:1520-4081
1522-7278
DOI:10.1002/tox.22395