Interaction of aflatoxin B1 and fumonisin B1 in HepG2 cell apoptosis
2017
Du, Ming | Liu, Yang | Zhang, Genyi
Aflatoxin B1 (AFB1) and fumonisin B1 (FB1) are mycotoxins commonly coexisted in cereal-based ingredients or foods, and their co-apoptotic activity in HepG2 cells was studied to further the understanding of their combinative toxicity. The values of IC50, based on sulforhodamine B (SRB) colorimetric assay, were 9.5μM and 481.7μM for AFB1 and FB1, respectively, showing AFB1 is more toxic to HepG2 cells than FB1. The cytotoxicity was also evidenced by substantially decreased contents of cellular DNA and ATP accompanying an increase of intracellular ROS upon exposure to AFB1(1μM = 10% IC50), FB1 (70μM = 10% IC50) and their combinations. After HepG2 cells were arrested in S or G0/G1 phase after exposure to mycotoxins, flow cytometry assay on the rate of apoptosis showed a synergistic interaction (p < 0.01) between AFB1 and FB1 at dosage levels with equivalent toxicity of 10% and 30% measured by SRB assay. Consistently, immunocytochemistry analysis on the expression of apoptosis related proteins showed higher expression of Bax, Caspase 3, and p53 upon exposure to combinations of AFB1 and FB1 than their individual treatments at the dosages with the same equivalent level of toxicity. In the meantime, it seems that the expression of capase-8 is antagonistic between AFB1 and FB1, which indicates the synergetic proapoptotic activity of AFB1 and FB1 is likely caused by their different mechanisms in HepG2 cell apoptosis upon mycotoxin exposure.
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