TY - GEN A1 - Schulz, Christian A1 - Herzog, Natalie A1 - Kubick, Stefan A1 - Jung, Friedrich A1 - Küpper, Jan-Heiner T1 - Stable Chinese Hamster Ovary Suspension Cell Lines Harboring Recombinant Human Cytochrome P450 Oxidoreductase and Human Cytochrome P450 Monooxygenases as Platform for In Vitro Biotransformation Studies T2 - Cells N2 - In the liver, phase-1 biotransformation of drugs and other xenobiotics is largely facilitated by enzyme complexes consisting of cytochrome P450 oxidoreductase (CPR) and cytochrome P450 monooxygenases (CYPs). Generated from human liver-derived cell lines, recombinant in vitro cell systems with overexpression of defined phase-1 enzymes are widely used for pharmacological and toxicological drug assessment and laboratory-scale production of drug-specific reference metabolites. Most, if not all, of these cell lines, however, display some background activity of several CYPs, making it difficult to attribute effects to defined CYPs. The aim of this study was to generate cell lines with stable overexpression of human phase-1 enzymes based on Chinese hamster ovary (CHO) suspension cells. Cells were sequentially modified with cDNAs for human CPR in combination with CYP1A2, CYP2B6, or CYP3A4, using lentiviral gene transfer. In parallel, CYP-overexpressing cell lines without recombinant CPR were generated. Successful recombinant expression was demonstrated by mRNA and protein analyses. Using prototypical CYP-substrates, generated cell lines proved to display specific enzyme activities of each overexpressed CYP while we did not find any endogenous activity of those CYPs in parental CHO cells. Interestingly, cell lines revealed some evidence that the dependence of CYP activity on CPR could vary between CYPs. This needs to be confirmed in further studies. Recombinant expression of CPR was also shown to enhance CYP3A4-independent metabolisation of testosterone to androstenedione in CHO cells. We propose the novel serum-free CHO suspension cell lines with enhanced CPR and/or defined CYP activity as a promising “humanised” in vitro model to study the specific effects of those human CYPs. This could be relevant for toxicology and/or pharmacology studies in the pharmaceutical industry or medicine. KW - Chinese hamster ovary cells KW - CHO-K1 KW - CPR KW - CYP450 KW - cytochrome P450 monooxygenase KW - liver KW - NADPH P450 oxidoreductase KW - phase-1 biotransformation KW - serum-free KW - suspension cells Y1 - 2023 UR - https://www.mdpi.com/2073-4409/12/17/2140#metrics U6 - https://doi.org/10.3390/cells12172140 SN - 2073-4409 VL - 12 IS - 17 ER - TY - GEN A1 - Walter, Ruben Magnus A1 - Zemella, Anne A1 - Schramm, Marina A1 - Kiebist, Jan A1 - Kubick, Stefan T1 - Vesicle-based cell-free synthesis of short and long unspecific peroxygenases T2 - Frontiers in Bioengineering and Biotechnology N2 - Unspecific peroxygenases (UPOs, EC 1.11.2.1) are fungal enzymes that catalyze the oxyfunctionalization of non-activated hydrocarbons, making them valuable biocatalysts. Despite the increasing interest in UPOs that has led to the identification of thousands of putative UPO genes, only a few of these have been successfully expressed and characterized. There is currently no universal expression system in place to explore their full potential. Cell-free protein synthesis has proven to be a sophisticated technique for the synthesis of difficult-to-express proteins. In this work, we aimed to establish an insect-based cell-free protein synthesis (CFPS) platform to produce UPOs. CFPS relies on translationally active cell lysates rather than living cells. The system parameters can thus be directly manipulated without having to account for cell viability, thereby making it highly adaptable. The insect-based lysate contains translocationally active, ER-derived vesicles, called microsomes. These microsomes have been shown to allow efficient translocation of proteins into their lumen, promoting post-translational modifications such as disulfide bridge formation and N-glycosylations. In this study the ability of a redox optimized, vesicle-based, eukaryotic CFPS system to synthesize functional UPOs was explored. The influence of different reaction parameters as well as the influence of translocation on enzyme activity was evaluated for a short UPO from Marasmius rotula and a long UPO from Agrocybe aegerita. The capability of the CFPS system described here was demonstrated by the successful synthesis of a novel UPO from Podospora anserina, thus qualifying CFPS as a promising tool for the identification and evaluation of novel UPOs and variants thereof. KW - cell-free protein synthesis KW - enzymes KW - unspecific peroxygenases KW - insect cell lysate Y1 - 2022 U6 - https://doi.org/10.3389/fbioe.2022.964396 SN - 2296-4185 VL - 10 ER - TY - GEN A1 - Knauer, Jan Felix A1 - Schulz, Christian A1 - Zemella, Anne A1 - Wüstenhagen, Doreen A. A1 - Walter, Ruben Magnus A1 - Küpper, Jan-Heiner A1 - Kubick, Stefan T1 - Synthesis of mono Cytochrome P450 in a modified CHO-CPR cell-free protein production platform T2 - Scientific Reports N2 - AbstractCytochromes P450 (CYPs) are a group of monooxygenases that can be found in almost all kinds of organisms. For CYPs to receive electrons from co-substrate NADPH, the activity of NADPH-Cytochrome-P450-oxidoreductase (CPR) is required as well. In humans, CYPs are an integral part of liver-based phase-1 biotransformation, which is essential for the metabolization of multiple xenobiotics and drugs. Consequently, CYPs are important players during drug development and therefore these enzymes are implemented in diverse screening applications. For these applications it is usually advantageous to use mono CYP microsomes containing only the CYP of interest. The generation of mono-CYP containing mammalian cells and vesicles is difficult since endogenous CYPs are present in many cell types that contain the necessary co-factors. By obtaining translationally active lysates from a modified CHO-CPR cell line, it is now possible to generate mono CYPs in a cell-free protein synthesis process in a straightforward manner. As a proof of principle, the synthesis of active human CYPs from three different CYP450 gene families (CYP1A2, CYP2B6 and CYP3A4), which are of outstanding interest in industry and academia was demonstrated. Luciferase based activity assays confirm the activity of the produced CYPs and enable the individual adaptation of the synthesis process for efficient cell-free enzyme production. Furthermore, they allow for substrate and inhibitor screenings not only for wild-type CYPs but also for mutants and further CYP isoforms and variants. As an example, the turnover of selected CYP substrates by cell-free synthesized CYPs was demonstrated via an indirect luciferase assay-based screening setup. KW - Multidisciplinary Y1 - 2024 U6 - https://doi.org/10.1038/s41598-024-51781-6 SN - 2045-2322 VL - 14 ER -