@misc{KruegerGengeSteinbrechtKuepperetal., author = {Kr{\"u}ger-Genge, Anne and Steinbrecht, Susanne and K{\"u}pper, Jan-Heiner and Lendlein, Andreas and Jung, Friedrich}, title = {Evidence for cytostatic effect of cyclophosphamide on human vein endothelial cells in cancer therapy: preliminary in vitro results.}, series = {Clinical Hemorheology and Microcirculation}, volume = {69}, journal = {Clinical Hemorheology and Microcirculation}, number = {1-2}, issn = {1875-8622}, doi = {10.3233/CH-189125}, pages = {267 -- 276}, language = {en} } @misc{SteinbrechtKoenigSchmidtkeetal., author = {Steinbrecht, Susanne and K{\"o}nig, Rosalie and Schmidtke, Kai-Uwe and Herzog, Natalie and Scheibner, Katrin and Kr{\"u}ger-Genge, Anne and Jung, Friedrich and Kammerer, Sarah and K{\"u}pper, Jan-Heiner}, title = {Metabolic activity testing can underestimate acute drug cytotoxicity as revealed by HepG2 cell clones overexpressing cytochrome P450 2C19 and 3A4}, series = {Toxicology}, volume = {412}, journal = {Toxicology}, issn = {0300-483X}, doi = {10.1016/j.tox.2018.11.008}, pages = {37 -- 47}, language = {en} } @misc{SteinbrechtKammererKuepper, author = {Steinbrecht, Susanne and Kammerer, Sarah and K{\"u}pper, Jan-Heiner}, title = {HepG2 cells with recombinant cytochrome P450 enzyme overexpression: Their use and limitation as in vitro liver model}, series = {Journal of Cellular Biotechnology}, volume = {5}, journal = {Journal of Cellular Biotechnology}, number = {1}, issn = {2352-3697}, doi = {10.3233/JCB-189013}, pages = {55 -- 64}, language = {en} } @misc{HailekaGeorgeSteinbrechtetal., author = {Haileka, Vanessa and George, Sandra and Steinbrecht, Susanne and Jung, Friedrich and Reinehr, R. and K{\"u}pper, Jan-Heiner}, title = {Colon cancer cells cultured under hyperosmotic conditions as in vitro model to investigate dehydration effects on cancer drug susceptibility}, series = {Clinical Hemorheology and Microcirculation}, volume = {73}, journal = {Clinical Hemorheology and Microcirculation}, number = {1}, issn = {1875-8622}, doi = {10.3233/CH-199210}, pages = {169 -- 176}, language = {en} } @misc{SteinbrechtPfeiferHerzogetal., author = {Steinbrecht, Susanne and Pfeifer, Nadine and Herzog, Natalie and Katzenberger, Nadine and Schulz, Christian and Kammerer, Sarah and K{\"u}pper, Jan-Heiner}, title = {HepG2-1A2 C2 and C7: Lentivirus vector-mediated stable and functional overexpression of cytochrome P450 1A2 in human hepatoblastoma cells}, series = {Toxicology Letters}, volume = {319}, journal = {Toxicology Letters}, issn = {0378-4274}, doi = {10.1016/j.toxlet.2019.11.006}, pages = {155 -- 159}, abstract = {Novel HepG2 cell clones 1A2 C2 and 1A2 C7 were independently generated by lentiviral transduction to functionally overexpress cytochrome P450 1A2 (CYP1A2). We found similar and stable CYP1A2 transcript and protein levels in both cell clones leading to specific enzyme activities of about 370 pmol paracetamol x min-1 x mg-1 protein analyzed by phenacetin conversion. Both clones showed dramatically increased sensitivity to the hepatotoxic compound aflatoxin B1 (EC50<100 nM) when compared to parental HepG2 cells (EC50 ∼5 μM). Thus, newly established cell lines are an appropriate tool to study metabolism and toxicity of substances depending on conversion by CYP1A2.}, language = {en} } @misc{SteinbrechtKiebistKoenigetal., author = {Steinbrecht, Susanne and Kiebist, Jan and K{\"o}nig, Rosalie and Thiessen, Markus and Schmidtke, Kai-Uwe and Kammerer, Sarah and K{\"u}pper, Jan-Heiner and Scheibner, Katrin}, title = {Synthesis of cyclophosphamide metabolites by a peroxygenase from Marasmius rotula for toxicological studies on human cancer cells}, series = {AMB Express}, volume = {10}, journal = {AMB Express}, issn = {2191-0855}, doi = {10.1186/s13568-020-01064-w}, pages = {13}, abstract = {Cyclophosphamide (CPA) represents a widely used anti-cancer prodrug that is converted by liver cytochrome P450 (CYP) enzymes into the primary metabolite 4-hydroxycyclophosphamide (4-OH-CPA), followed by non-enzymatic generation of the bioactive metabolites phosphoramide mustard and acrolein. The use of human drug metabolites as authentic standards to evaluate their toxicity is essential for drug development. However, the chemical synthesis of 4-OH-CPA is complex and leads to only low yields and undesired side products. In past years, fungal unspecific peroxygenases (UPOs) have raised to powerful biocatalysts. They can exert the identical selective oxyfunctionalization of organic compounds and drugs as known for CYP enzymes with hydrogen peroxide being used as sole cosubstrate. Herein, we report the efficient enzymatic hydroxylation of CPA using the unspecific peroxygenase from Marasmius rotula (MroUPO) in a simple reaction design. Depending on the conditions used the primary liver metabolite 4-OH-CPA, its tautomer aldophosphamide (APA) and the overoxidized product 4-ketocyclophosphamide (4-keto-CPA) could be obtained. Using a kinetically controlled approach 4-OH-CPA was isolated with a yield of 32\% (purity > 97.6\%). Two human cancer cell lines (HepG2 and MCF-7) were treated with purified 4-OH-CPA produced by MroUPO (4-OH-CPAUPO). 4-OH-CPAUPO-induced cytotoxicity as measured by a luminescent cell viability assay and its genotoxicity as measured by γH2AX foci formation was not significantly different to the commercially available standard. The high yield of 4-OH-CPAUPO and its biological activity demonstrate that UPOs can be efficiently used to produce CYP-specific drug metabolites for pharmacological assessment.}, language = {en} } @misc{KruegerGengeSteinbrechtJungetal., author = {Kr{\"u}ger-Genge, Anne and Steinbrecht, Susanne and Jung, Conrad H. G. and Westphal, Sophia and Kl{\"o}pzig, Stefanie and Waldeck, Peter and K{\"u}pper, Jan-Heiner and Storsberg, J. and Jung, Friedrich}, title = {Arthrospira platensis accelerates the formation of an endothelial cell monolayer and protects against endothelial cell detachment after bacterial contamination}, series = {Clinical Hemorheology and Microcirculation}, volume = {78}, journal = {Clinical Hemorheology and Microcirculation}, number = {2}, issn = {1386-0291}, doi = {10.3233/CH-201096}, pages = {151 -- 161}, abstract = {Within the last years a comprehensive number of scientific studies demonstrated beneficial effect of Arthropira platensis (AP) as dietary supplement due to a high content of proteins, minerals and vitamins. Positive effects like promoting the immune system, reducing inflammation and an anti-oxidant capacity are reported. In this study, the effect of an aqueous AP extract on primary human venous endothelial cells (HUVEC) was investigated. In addition, the effect of AP on HUVEC treated with a bacterial toxin (lipopolysaccharide, LPA), inducing an activation of HUVEC and cellular detachment, was analyzed. Depending on the concentration of AP extract a significantly accelerated formation of an endothelial cell monolayer was observed. Furthermore, the detachment of HUVEC after LPA addition was dramatically reduced by AP. In conclusion, the data are promising and indicatory for an application of Arthrospira platensis in the clinical field.}, language = {en} }