Abstract 12279: Novel and Reliable Method to Screen for Drug Cardiac Toxicity Using Human Induced Pluripotent Stem Cell Derived Cardiomyocytes (hiPS-CM)

Unexpected cardiotoxicity underlies high rates of attrition during drug development, posing a multi-billion dollar burden on the pharmaceutical industry. Over reliance on the use of animals and materials derived from animals in preclinical assays to predict the cardiotoxic effect of new drugs in humans has contributed to this problem. The drug responses in human cardiomyocytes compared to animal-derived primary cardiomyocytes (CM) for in vitro assays is not always the same. Here, we describe a combination of human pluripotent stem cell-derived cardiomyocytes (hiPS-CM) and high content analysis confocal microscopy as a potential solution for this major setback in drug development. Initially human skin fibroblasts were reprogrammed into human induced pluripotent stem cells (hiPSCs) by lentiviral transduction and utilization of the following combination of transcription factors: Oct3/4, Sox2, c-Myc and Klf4. The human pluripotent stem cell phenotype of the generated hIPSCs was confirmed. hiPSCs were differentiated into cardiomyocytes and the cardiac cell phenotype was confirmed by immunofluorescence and RT-PCR analysis of cardiac markers i.e. αMHC, cTNT, NKX2.5 and connexin 43. Seventeen known cardiotoxic compounds, as well as controls, were applied to the cells in 384 well format at a dose of 10μM for 48 hours. Then hiPSC-CM underwent confocal microscopy high content analysis to simultaneously evaluate the cell mitochondrial transmembrane potential (using TMRM dye), and plasma membrane permeability (using TOTO-3 dye). All known cardiotoxins showed a significant decrease in mitochondrial transmembrane potential ranging from 74% to 95% and an increase in plasma membrane permeability ranging from 67-327 fold in comparison to the controls. These results showed 100% prediction rate of cardiotoxicity of known cardiotoxins by hiPS-CM. This was compared to only 12% general cytotoxicity prediction rate when these compounds tested on A549 and ACHN cancer cell lines. In conclusion, combining two state of the art technologies 1) hiPSC-CM and 2) confocal microscopy high content analysis, we were able to provide a reliable high throughput method to assess cardiotoxicity of compounds.