Reverse Phase Protein Arrays for High-throughput Toxicity Screening

High-throughput screening is extensively applied for identification of drug targets and drug discovery and recently it found entry into toxicity testing. Reverse phase protein arrays (RPPAs) are used widespread for quantification of protein markers. We reasoned that RPPAs also can be utilized beneficially in automated high-throughput toxicity testing. An advantage of using RPPAs is that, in addition to the baseline toxicity readout, they allow testing of multiple markers of toxicity, such as inflammatory responses, which do not necessarily cumulate in cell death. We used transfection of siRNAs with known killing effects as a model system to demonstrate that RPPA-based protein quantification can serve as substitute readout of cell viability, hereby reliably reflecting toxicity. In terms of automation, cell exposure, protein harvest, serial dilution and sample reformatting were performed using a robotic screening platform. Furthermore, we automated sample tracking and data analysis by developing a bundled bioinformatics tool named “MIRACLE”.
Automation and RPPA-based viability/toxicity readouts enable rapid testing of large sample numbers, while granting the possibility for flexible consecutive quantification of additional user-defined toxicity markers.