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The human genome is persistently exposed to damage caused by xenobiotics, therefore the assessment of genotoxicity of substances having a direct contact with humans is of importance. Phthalates are commonly used in industrial applications. Widespread exposure to phthalates has been evidenced by their presence in human body fluids. We have assessed the genotoxic potential of selected phthalates and mechanism of their action in human peripheral blood mononuclear cells (PBMCs). Studied cells were incubated with di-n-butyl phthalate (DBP), butylbenzyl phthalate (BBP) and their metabolites: mono-n-butylphthalate (MBP), mono-benzylphthalate (MBzP) in the concentrations range of 0.1-10 µg/mL for 24 h. Analyzed compounds induced DNA single and double strand-breaks (DBP and BBP ≥ 0.5 µg/mL, MBP and MBzP ≥ 1 µg/mL) and more strongly oxidized purines than pyrimidines. None of the compounds examined was capable of creating adducts with DNA. All studied phthalates caused an increase of total ROS level, while hydroxyl radical was generated mostly by DBP and BBP. PBMCs exposed to DBP and BBP could not completely repair DNA strand-breaks during 120 min of postincubation, in opposite to damage caused by their metabolites, MBP and MBzP. We have concluded that parent phthalates: DBP and BBP caused more pronounced DNA damage compared to their metabolites.

Glyphosate is the most heavily applied among pesticides in the world, and thus human exposure to this substance continues to increase. WHO changed classification of glyphosate to probably cancerogenic to humans, thus there is urgent need to assess in detail genotoxic mechanism of its action. We have assessed the effect of glyphosate, its formulation (Roundup 360 PLUS) and its main metabolite (aminomethylphosphonic acid, AMPA) in the concentration range from 1 to 1000 μM on DNA damage in human peripheral blood mononuclear cells (PBMCs). The cells were incubated for 24 h. The compounds studied and formulation induced DNA single and double strand-breaks and caused purines and pyrimidines oxidation. None of compounds examined was capable of creating adducts with DNA, while those substances increased ROS (including • OH) level in PBMCs. Roundup 360 PLUS caused damage to DNA even at 5 μM, while glyphosate and particularly AMPA induced DNA lesions from the concentration of 250 μM and 500 μM, respectively. DNA damage induced by glyphosate and its derivatives increased in order: AMPA, glyphosate, Roundup 360 PLUS. We may conclude that observed changes were not associated with direct interaction of xenobiotics studied with DNA, but the most probably they occurred through ROS-mediated effects., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Because bisphenol A (BPA) and some of its analogs have been supposed to influence development of cancer, we have assessed the effect of BPA, bisphenol S (BPS), bisphenol F (BPF) and bisphenol AF (BPAF) on DNA bases oxidation, which is a key process in cancer initiation. The analysis was conducted on human peripheral blood mononuclear cells (PBMCs), which are very useful model to assess genotoxic potential of various toxicants in different cell types. In order to determine oxidative damage to DNA pyrimidines and purines, alkaline version of the comet assay with DNA glycosylases, i.e. endonuclease III (Nth) and human 8-oxoguanine DNA glycosylase (hOGG1) was used. PBMCs were exposed to BPA or its analogs in the concentrations of 0.01, 0.1 and 1 μg/mL for 4 h and 0.001, 0.01 and 0.1 μg/mL for 48 h. We have observed that BPA, BPS, BPF and particularly BPAF caused oxidative damage to DNA pyrimidines and more strongly to purines in human PBMCs. The results have also shown that BPS, which is the most commonly used as a substitute for BPA in the manufacture induced definitely the smallest oxidative DNA bases lesions in PBMCs. Moreover, we have noticed that BPA, BPF and BPAF caused DNA damage at very low concentration of 1 ng/mL., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Glyphosate is a very important herbicide that is widely used in the agriculture, and thus the exposure of humans to this substance and its metabolites has been noted. The purpose of this study was to assess DNA damage (determination of single and double strand-breaks by the comet assay) as well as to evaluate DNA methylation (global DNA methylation and methylation of p16 (CDKN2A) and p53 (TP53) promoter regions) in human peripheral blood mononuclear cells (PBMCs) exposed to glyphosate. PBMCs were incubated with the compound studied at concentrations ranging from 0.1 to 10 mM for 24 h. The study has shown that glyphosate induced DNA lesions, which were effectively repaired. However, PBMCs were unable to repair completely DNA damage induced by glyphosate. We also observed a decrease in global DNA methylation level at 0.25 mM of glyphosate. Glyphosate at 0.25 mM and 0.5 mM increased p53 promoter methylation, while it did not induce statistically significant changes in methylation of p16 promoter. To sum up, we have shown for the first time that glyphosate (at high concentrations from 0.5 to 10 mM) may induce DNA damage in leucocytes such as PBMCs and cause DNA methylation in human cells., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

In the present study, we have investigated DNA-damaging potential of BPA and its analogs, i.e. bisphenol S (BPS), bisphenol F (BPF) and bisphenol AF (BPAF) in human peripheral blood mononuclear cells (PBMCs) using the alkaline and neutral versions of the comet assay, which allowed to evaluate DNA single strand-breaks (SSBs) and double strand-breaks (DSBs). The use of the alkaline version of comet assay made also possible to analyze the kinetics of DNA repair in PBMCs after exposure of the cells to BPA or its analogs. We have observed an increase in DNA damage in PBMCs treated with BPA or its analogs in the concentrations ranging from 0.01 to 10 μg/ml after 1 and 4 h incubation. It was noted that bisphenols studied caused DNA damage mainly via SSBs, while DNA fragmentation via double DSBs was low. The strongest changes in DNA damage were provoked by BPA and particularly BPAF, which were capable of inducing SSBs even at 0.01 μg/ml, while BPS caused the lowest changes (only at 10 μg/ml). We have also observed that PBMCs significantly repaired bisphenols-induced DNA damage but they were unable (excluding cells treated with BPS) to repair totally DNA breaks., (Copyright © 2016 Elsevier Ltd. All rights reserved.)