8‐Hydroxy‐2′‐deoxyguanosine as a biomarker of oxidative DNA damage induced by perfluorinated compounds in TK6 cells

Abstract

8-Hydroxy-2'-deoxyguanosine (8-OHdG) is the most common biomarker of oxidative DNA damage, it is formed by chemical carcinogens and can be measured in any species. Perfluorooctanoic acid (PFOA) and perfluorononanoic acid (PFNA) are suspected genotoxic carcinogens through induction of reactive oxygen species that are responsible for oxidative DNA damage. This study was conducted to investigate the in vitro genotoxicity of PFOA and PFNA in human lymphoblastoid (TK6) cell line. TK6 cells were exposed to PFOA at 0, 125, 250, and 500 ppm and PFNA at 125 and 250 ppm for 2 h. Single cell gel electrophoresis (comet assay) was used to measure DNA damage; at least 50 cells per sample were analyzed using comet Assay Software Project (CASP). 8-OHdG was measured in DNA of exposed cells using high-performance liquid chromatography (HPLC)-mass spectrometry (MS)/MS. Results showed that both PFOA and PFNA induced DNA damage indicated by increased tail length (DNA migration). The level of 8-OHdG was increased in a dose-dependent manner in both PFOA and PFNA exposure. We concluded that PFOA and PFNA induced DNA damage and the biomarker of oxidative DNA damage (8-OHdG) could be measured by HPLC-MS/MS. In addition, PFNA produced high level of 8-OHdG at concentrations lower than PFOA, this may indicate that PFNA is more potent genotoxicant for TK6 cells than PFOA.

Impact of dietary manganese on experimental colitis in mice

“…The levels of 8‐isoprostane after DSS administration were significantly higher in the Mn‐deficient than in the Mn‐adequate mice (Figure H), indicating that Mn protects against lipid peroxidation in this mouse colitis model. The 8‐OHdG biomarker is excreted during the repair of DNA damage, thereby providing a quantitative index of oxidative DNA damage . The 8‐OHdG levels were significantly increased in the serum of Mn‐deficient mice after DSS injury (Figure I), indicating that Mn protects against oxidative stress‐associated DNA damage in this mouse colitis model.…”

“…The 8-OHdG biomarker is excreted during the repair of DNA damage, thereby providing a quantitative index of oxidative DNA damage. 21 The 8-OHdG levels were significantly increased in the serum of Mn-deficient mice after DSS injury Figure 4I), indicating that Mn protects against oxidative stress-associated DNA damage in this mouse colitis model. Mn deficiency, therefore, reduced cellular MnSOD activity and increased oxidative stress in the mouse model of DSSinduced colitis.…”

Perfluoroalkylated Substance Effects in Xenopus laevis A6 Kidney Epithelial Cells Determined by ATR-FTIR Spectroscopy and Chemometric Analysis

“…In fact, PFOA and PFNA are suspected genotoxic carcinogens through induction of reactive oxygen species that are responsible for oxidative DNA damage. Recently, Yahia et al 49 demonstrated that PFOA and PFNA induced DNA damage in TK6 cells, observing that PFNA produced high levels of 8-hydroxy-2′-deoxyguanosine (8-OhdG), a biomarker of oxidative DNA damage. In contrast, in experiment 2, all PFAS substances caused alterations associated with secondary structures of proteins (Amide I, Amide II, and Amide III) (see Figure S2 and Table S1 ).…”

NTP Technical Report on the Toxicity Studies of Perfluoroalkyl Carboxylates (Perfluorohexanoic Acid, Perfluorooctanoic Acid, Perfluorononanoic Acid, and Perfluorodecanoic Acid) Administered by Gavage to Sprague Dawley (Hsd:Sprague Dawley SD) Rats

“…DMSO is a known scavenger of free radicals and can protect DNA from oxidative damage 94 . In human lymphoblastoid TK6 cells, exposure to 0.25 or 0.5 mg/mL PFOA for 2 hours produced small but significant increases in DNA damage in the comet assay and in 8hydroxy-2ʹ-deoxyguanosine DNA adducts (per 10 5 dG) as detected using high-performance liquid chromatography (HPLC)-mass spectrometry (MS) 95 . Similar results were obtained for PFNA when tested at 0.125 or 0.25 mg/mL 95 .…”

“…In human lymphoblastoid TK6 cells, exposure to 0.25 or 0.5 mg/mL PFOA for 2 hours produced small but significant increases in DNA damage in the comet assay and in 8hydroxy-2ʹ-deoxyguanosine DNA adducts (per 10 5 dG) as detected using high-performance liquid chromatography (HPLC)-mass spectrometry (MS) 95 . Similar results were obtained for PFNA when tested at 0.125 or 0.25 mg/mL 95 . Exposure to PFOA at concentrations up to 300 µM for 5 or 24 hours did not induce DNA damage in Syrian hamster embryo cells as measured using the comet assay 96 .…”