(473b) Three-Dimensional Cell Culture Platform for High-Throughput Toxicity and Differentiation Screening of Human Neural Stem Cells

Drug discovery and toxicology use animal models for many purposes such as identifying therapeutic targets, assessing the efficacy of drug candidates and testing the safety of potential therapeutics and commercially available chemicals. While animal studies are valuable for these purposes, they are associated with high costs, low-throughput and results that do not translate well to humans. There is, therefore, significant interest in developing in vitro systems that use human cells to reduce costs, increase throughput, and improve reliability and predictability in drug and toxicity screening processes. Importantly, differences in toxicity between different types of human cells, such as stem cells compared to terminally differentiated cells, is largely unstudied. To this end, we have developed a microarray chip (microchip) platform for three-dimensional cell culture and high-throughput screening. Human neural stem cells (hNSC) were grown and differentiated on the microchip for periods up to two weeks and used to screen for chemical toxicants or modulators of differentiation. The cytotoxic dose responses and IC₅₀ values for 12 chemicals was measured for hNSC and their differentiated progeny on the microchip platform. Lower IC₅₀ values were observed for all-trans retinoic acid, 5-fluorouracil and cytosine arabinoside against hNSCs in comparison to their differentiated counterparts, which were predominantly astrocytic. This work demonstrates progress in developing in vitro screening systems for predicting human adult and developmental neurotoxicity. In addition, this work begins to address how different cell types have differential sensitivities to chemicals, which should be considered when performing screens.