Voltammetric detection of damage to DNA by arsenic compounds at a DNA biosensor

Abstract: DNA biosensor can serve as a powerfull tool for simple in vitro tests of chemical toxicity. In this paper, damage to DNA attached to the surface of screen-printed carbon electrode by arsenic compounds in solution is described. Using the Co(III) complex with 1,10-phenanthroline, [Co(phen)3] 3+, as an electrochemical DNA marker and the Ru(II) complex with bipyridyne, [Ru(bipy)3] 2+, as a DNA oxidation catalyst, the portion of original dsDNA which survives an incubation of the biosensor in the cleavage medium was evaluated. The model cleavage mixture was composed of an arsenic compound at 10-3 mol/L concentration corresponding to real contaminated water, 2x10-4 mol/L Fe(II) or Cu(II) ions as the redox catalyst, and 1.5x10-2 mol/L hydrogen peroxide. DNA damage by arsenite, dimethylarsinic acid as the metabolic product of inorganic arsenic and widely used herbicide, as well as phenylarsonic acid and p-arsanilic acid as the representatives of feed additives was found in difference to arsenate

Voltammetric Detection of Damage to DNA by Arsenic Compounds at a DNA Biosensor

DNA biosensor can serve as a powerfull tool for simple in vitro tests of chemicaltoxicity. In this paper, damage to DNA attached to the surface of screen-printed carbonelectrode by arsenic compounds in solution is described. Using the Co(III) complex with1,10-phenanthroline, [Co(phen)3]3+ , as an electrochemical DNA marker and the Ru(II)complex with bipyridyne, [Ru(bipy)3]2+ , as a DNA oxidation catalyst, the portion of originaldsDNA which survives an incubation of the biosensor in the cleavage medium was evaluated.The model cleavage mixture was composed of an arsenic compound at 10-3 mol/Lconcentration corresponding to real contaminated water, 2x10-4 mol/L Fe(II) or Cu(II) ions asthe redox catalyst, and 1.5x10-2 mol/L hydrogen peroxide. DNA damage by arsenite,dimethylarsinic acid as the metabolic product of inorganic arsenic and widely used herbicide,as well as phenylarsonic acid and p-arsanilic acid as the representatives of feed additives wasfound in difference to arsenate

P11.41 Comparison of fibroblast activation protein expression and localization in glioblastomas and brain metastases

Abstract BACKGROUND Fibroblast activation protein (FAP) is a transmembrane serine protease that is frequently upregulated in the tumor microenvironment. In several cases, FAP protein itself and/or FAP expressing stromal cells have been shown to contribute to cancer progression and to be associated with more aggressive cancer behaviour and shorter patient survival. The aim of this study was to determine FAP expression in glioblastomas and brain metastases and to identify the cell types that express FAP in the microenvironment of these malignancies. MATERIAL AND METHODS FAP enzymatic activity and protein concentration were determined in samples from patients with brain metastases, glioblastomas and pharmacoresistant epilepsy (control non-tumorous brain tissue) by an enzymatic assay using a specific fluorogenic substrate and ELISA, respectively. Immunohistochemical labelling with antibodies against FAP and markers of astroglia, epithelial cancer cells and mesenchymal stromal cells was performed to characterize FAP expressing cells. RESULTS FAP was significantly upregulated in the majority of glioblastomas and brain metastases in comparison to non-tumorous brain tissue. In glioblastomas, FAP was localized perivascularly and in mesenchymal cells, and in part of the tumors also in the glioma cells. In brain metastases, FAP positivity was abundantly present in the stroma and predominantly co-localised with markers of mesenchymal stromal cells (TE-7, SMA, PDGFRbeta, NG2), but there was no overlap between FAP and markers of epithelial cancer cells (EpCAM, pancytokeratin). CONCLUSION FAP is upregulated in the microenvironment of human glioblastomas and brain metastases compared to non-tumorous brain tissue. In glioblastomas, FAP is expressed in part of the glioma cells, in pericytes and mesenchymal stromal cells, whereas no positivity in cancer cells and more abundant FAP+ stroma was detected in brain metastases. The selective expression of FAP in these brain tumors may be useful for the visualization and possibly therapeutic targeting of their tumor microenvironment. GRANT SUPPORT Ministry of Health of the Czech Republic, grant No. 15-31379A, Progres Q28/LF1, 2015064 LM EATRIS and the project,Center for Tumor Ecology - Research of the Cancer Microenvironment Supporting Cancer Growth and Spread” (reg. n. CZ.02.1.01/0.0/0.0/16_019/0000785) supported by the Operational Programme Research, Development and Education. </jats:sec