TY - JOUR A1 - Unterberg, Marlies A1 - Leffers, Larissa A1 - Hübner, Florian A1 - Humpf, Hans-Ulrich A1 - Lepikhov, Konstantin A1 - Walter, Jörn A1 - Ebert, Franziska A1 - Schwerdtle, Tanja T1 - Toxicity of arsenite and thio-DMAV after long-term (21 days) incubation of human urothelial cells: cytotoxicity, genotoxicity and epigenetics JF - Toxicology Research N2 - This study aims to further mechanistically understand toxic modes of action after chronic inorganic arsenic exposure. Therefore long-term incubation studies in cultured cells were carried out, to display chronically attained changes, which cannot be observed in the generally applied in vitro short-term incubation studies. Particularly, the cytotoxic, genotoxic and epigenetic effects of an up to 21 days incubation of human urothelial (UROtsa) cells with pico- to nanomolar concentrations of iAsIII and its metabolite thio-DMAV were compared. After 21 days of incubation, cytotoxic effects were strongly enhanced in the case of iAsIII and might partly be due to glutathione depletion and genotoxic effects on the chromosomal level. These results are in strong contrast to cells exposed to thio-DMAV. Thus, cells seemed to be able to adapt to this arsenical, as indicated among others by an increase in the cellular glutathione level. Most interestingly, picomolar concentrations of both iAsIII and thio-DMAV caused global DNA hypomethylation in UROtsa cells, which was quantified in parallel by 5-medC immunostaining and a newly established, reliable, high resolution mass spectrometry (HRMS)-based test system. This is the first time that epigenetic effects are reported for thio-DMAV; iAsIII induced epigenetic effects occur in at least 8000 fold lower concentrations as reported in vitro before. The fact that both arsenicals cause DNA hypomethylation at really low, exposure-relevant concentrations in human urothelial cells suggests that this epigenetic effect might contribute to inorganic arsenic induced carcinogenicity, which for sure has to be further investigated in future studies. KW - induced malignant-transformation KW - genomic dna methylation KW - vitro toxicological characterization KW - thio-dimethylarsinic acid KW - bladder-cancer KW - methyltransferases dnmt3a KW - cytosine methylation KW - carcinogen exposure KW - mass-spectrometry KW - gene-expression Y1 - 2014 SN - 2045-4538 SN - 2045-452X VL - 3 IS - 6 SP - 456 EP - 464 PB - Royal Society of Chemistry CY - Cambridge ER - TY - GEN A1 - Unterberg, Marlies A1 - Leffers, Larissa A1 - Hübner, Florian A1 - Humpf, Hans-Ulrich A1 - Lepikhov, Konstantin A1 - Walter, Jörn A1 - Ebert, Franziska A1 - Schwerdtle, Tanja T1 - Toxicity of arsenite and thio-DMAV after long-term (21 days) incubation of human urothelial cells: cytotoxicity, genotoxicity and epigenetics N2 - This study aims to further mechanistically understand toxic modes of action after chronic inorganic arsenic exposure. Therefore long-term incubation studies in cultured cells were carried out, to display chronically attained changes, which cannot be observed in the generally applied in vitro short-term incubation studies. Particularly, the cytotoxic, genotoxic and epigenetic effects of an up to 21 days incubation of human urothelial (UROtsa) cells with pico- to nanomolar concentrations of iAsIII and its metabolite thio-DMAV were compared. After 21 days of incubation, cytotoxic effects were strongly enhanced in the case of iAsIII and might partly be due to glutathione depletion and genotoxic effects on the chromosomal level. These results are in strong contrast to cells exposed to thio-DMAV. Thus, cells seemed to be able to adapt to this arsenical, as indicated among others by an increase in the cellular glutathione level. Most interestingly, picomolar concentrations of both iAsIII and thio-DMAV caused global DNA hypomethylation in UROtsa cells, which was quantified in parallel by 5-medC immunostaining and a newly established, reliable, high resolution mass spectrometry (HRMS)-based test system. This is the first time that epigenetic effects are reported for thio-DMAV; iAsIII induced epigenetic effects occur in at least 8000 fold lower concentrations as reported in vitro before. The fact that both arsenicals cause DNA hypomethylation at really low, exposure-relevant concentrations in human urothelial cells suggests that this epigenetic effect might contribute to inorganic arsenic induced carcinogenicity, which for sure has to be further investigated in future studies. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 178 KW - induced malignant-transformation KW - genomic dna methylation KW - vitro toxicological characterization KW - thio-dimethylarsinic acid KW - bladder-cancer KW - methyltransferases dnmt3a KW - cytosine methylation KW - carcinogen exposure KW - mass-spectrometry KW - gene-expression Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-76239 SP - 456 EP - 464 ER -