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entist's or even their own experiments, respectively (Baker and Penny, 2016;Miyakawa, 2020). Among the factors contributing to this reproducibility crisis are selective reporting, low statistical power, or poor analysis and experimental design (Baker and Penny, 2016). In addition, poor starting material -especially for hiPSC research -can be a severe source of irreproducibility (Stacey et al., 2013;Pamies et al., 2017). Therefore, already in 2013 "an urgent need" to establish routine screening methods for the characterization of quality-controlled stem cells was identified (Stacey et al., 2013;Crook et al., 2017).While there is guidance available for Good In Vitro Methods Practices in general (OECD, 2018) or stem cell-based Good Cell Culture Practice specifically (Pamies et al., 2017(Pamies et al., , 2018(Pamies et al., , 2020, giving detailed insights into the broad subject of quality assurance (QA) and quality control (QC) of in vitro (stem cell-based) methods, these leave the average academic researcher with a plethora of QC assays, discussing pros and cons that might or

Limitations in genetic stability and recapitulating accurate physiological disease properties challenge the utility of patient-derived (PD) cancer models for reproducible and translational research. A portfolio of isogenic human induced pluripotent stem cells (hiPSCs) with different pan-cancer relevant oncoprotein signatures followed by differentiation into lineage-committed progenitor cells was genetically engineered.Characterization on molecular and biological level validated successful stable genetic alterations in pluripotency state as well as upon differentiation to prove the functionality of our approach. Meanwhile proposing core molecular networks possibly involved

The currently accepted methods for neurotoxicity (NT) testing rely on animal studies. However, high costs and low testing throughput hinder their application for large numbers of chemicals. To overcome these limitations, in vitro methods are currently being developed based on human-induced pluripotent stem cells (hiPSC) that allow higher testing throughput at lower costs. We applied six different protocols to generate 3D BrainSphere models for acute NT evaluation. These include three different media for 2D neural induction and two media for subsequent 3D differentiation resulting in self-organized, organotypic neuron/astrocyte microtissues. All induction protocols yielded nearly 100% NESTIN-positive hiPSC-derived neural progenitor cells (hiNPCs), though with different gene expression profiles concerning regional patterning. Moreover, gene expression and immunocytochemistry analyses revealed that the choice of media determines neural differentiation patterns. On the functional level, BrainSpheres exhibited different levels of electrical activity on microelectrode arrays (MEA). Spike sorting allowed BrainSphere functional characterization with the mixed cultures consisting of GABAergic, glutamatergic, dopaminergic, serotonergic, and cholinergic neurons. A test method for acute NT testing, the human multi-neurotransmitter receptor (hMNR) assay, was proposed to apply such MEA-based spike sorting. These models are promising tools not only in toxicology but also for drug development and disease modeling.

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