Abstract 13272: Modeling Cardiotoxicity Utilizing Human Pluripotent Stem Cell-Derived Cardiomyocytes: Towards Protective Therapy for the Heart

Abstract

Introduction: Cardiotoxicity is one of the main adverse effects of cancer therapy and has been extensively assessed in animal models which are not predictive for drug-induced cardiotoxicity in humans. Human pluripotent stem cell (hPSC)-derived cardiomyocytes provide a reliable source of human cardiomyocytes and have already proven valuable for cardiotoxicity studies. We present here a versatile screening platform, utilizing hPSC-cardiomyocytes, for assessing different aspects of cardiotoxicity. Methods and Results: A well-known group of anticancer drugs that cause therapy induced cardiotoxicity are anthracyclines. To validate their toxicity on human cells we compared the uptake of Doxorubicin (DOXO) and two of its analogues Amrubicin (AMR) and Aclarubicin (ACLA) into cardiomyocytes and fast dividing hPSCs. We utilized high throughput time-lapse imaging of cardiomyocytes differentiated from an NKX2.5 eGFP -α-actinin mRuby2 hPSC reporter for assessment of viability and sarcomeric disarray by creating binary masks of the fluorescent area. After 5 days less than 25% of sarcomeres were still present and about 20% of cardiomyocytes survived treatment with 1 μM DOXO or ACLA. Moreover, we evaluated the cardiotoxic effect on a functional level by evaluating calcium transients and identified faster rates after DOXO or ACLA treatment. In addition to analysis in 2D monolayers, we also established a more advanced platform for creating 3D engineered heart tissues, more closely resembling the human heart, which allowed us to measure the effect of a cumulative drug dose on cardiac contraction. We quantified contractile force and kinetics every 12 h for 3 days and observed total loss of contraction 60 h after treatment with 5 or 10 μM DOXO, 75% reduction with 5 μM ACLA and no loss of contraction with 5 μM AMR.To study different damage mechanisms, we investigated apoptotic marker Annexin V, DNA damage marker pH2AX, calcium accumulation and expression of cardiac genes. Conclusion: These assays enabled us to study the cardiotoxic effect of DOXO and two analogues on hPSC-derived cardiomyocytes. Most importantly, treatment with AMR had no effect on cardiac function. Ultimately our platform for assessing cardiotoxicity will lead to a better and safer treatment of patients.