Ingrit Hamann

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Inorganic arsenic is a strong, widespread human carcinogen. How exactly inorganic arsenic exerts carcinogenicity in humans is as yet unclear, but it is thought to be closely related to its metabolism. At exposure-relevant concentrations arsenic is neither directly DNA reactive nor mutagenic. Thus, more likely epigenetic and indirect genotoxic effects, among(More)
Copper is an essential trace element involved, among other functions, in enzymatic antioxidative defense systems. However, nonprotein bound copper ions have been shown to generate reactive oxygen species. To gain insight into the discrepancy between the protective properties of copper on the one hand and its toxicity on the other hand, we examined the(More)
FoxO transcription factors and their regulators in the phosphoinositide 3'-kinase (PI3K)/Akt signaling pathway play an important role in the control of cellular processes involved in carcinogenesis, such as proliferation and apoptosis. We have previously demonstrated that physiologically relevant heavy metal ions, such as copper or zinc ions, can stimulate(More)
Oxidative stress is involved in many diseases, and the search for appropriate biomarkers is one major focus in molecular epidemiology. 8-Oxoguanine (8-oxoG), a potentially mutagenic DNA lesion, is considered to be a sensitive biomarker for oxidative stress. Another approach consists in assessing the repair capacity towards 8-oxoG, mediated predominantly by(More)
The tumor suppressor protein p53, often called the guardian of the genome, is involved in important cellular processes, such as cell cycle control, apoptosis and DNA repair. With respect to BER, p53 might physically interact with and affect the transcription of different BER proteins such as hOGG1, APE1 or Polβ. In studies in HCT116 p53(-/-) cells(More)
Lysyl oxidase (LOX; ExPASy ENZYME entry: EC and members of the LOX-like family, LOXL1–LOXL4, are copper-dependent enzymes that can modify proteins of the extracellular matrix. Expression of LOX is elevated in many human cancers, including breast cancer. LOX expression correlates with the level of tissue hypoxia, and it is known to play a critical(More)
FHRE-Luc is a promoter reporter construct that is widely used to assess the activity of FoxO (forkhead box, class O) transcription factors. We here demonstrate that this promoter construct responds to exposure of HepG2 human hepatoma cells to known agonists of the aryl hydrocarbon receptor (AhR), 3-methylcholanthrene, benzo(a)pyrene, and(More)
Epidemiological studies have indicated a relationship between the prevalence of diabetes and exposure to arsenic. Mechanisms by which arsenic may cause this diabetogenic effect are largely unknown. The phosphoinositide 3′-kinase (PI3K)/Akt signaling pathway plays an important role in insulin signaling by controlling glucose metabolism, in part through(More)
Copper ions are known to induce insulin-like effects in various cell lines, stimulating the phosphoinositide 3'-kinase (PI3K)/Akt signaling cascade and leading to the phosphorylation of downstream targets, including FoxO transcription factors. The aim of this work was to study the role of insulin- and IGF1-receptors (IR and IGF1R) in insulin-like signaling(More)
The identification of appropriate biomarkers for oxidative stress is one major aim in molecular epidemiology. Besides the quantification of specific DNA lesions such as of 8-oxoguanine (8oxoG), another approach consists in the assessment of the repair capacity towards 8oxoG, mediated predominantly by the human 8-oxoguanine DNA glycosylase 1 (hOGG1); further(More)