Reveal the Role of Store-Operated Calcium Entry in Epirubicin-induced Acute Oxidative Stress in Cardiomyocytes

Epirubicin (EPI) is a widely used anthracycline chemotherapy drug, whose use is limited by its side effects including cardiomyopathy, hypertrophy and chronic heart failure. The cardiotoxicity of EPI has been linked to the generation of reactive oxygen species (ROS) in mitochondria and disruption of cardiac ryanodine receptor Ca 2+ release channel in the sarcoplasmic reticulum membrane. As Store‐Operated Calcium Entry (SOCE) is important in regulating intracellular Ca 2+ signaling, we tested whether dysregulated SOCE was also involved in EPI‐induced acute cardiotoxicity. This study compared intracellular ROS levels using fluorescent probe dihydroethidium (DHE) in EPI‐treated HL‐1, an adult mouse atrial cardiomyocyte cell line. Treatment of EPI at 1uM for 30min significantly increased intracellular ROS levels in HL‐1 compared with vehicle‐treated cells (3.8fold, p<0.0001). HL‐1 cells were then treated with 20uM BTP2, a potent SOCE inhibitor, for 30min. However, BTP2 failed to significantly decrease the EPI‐induced intracellular ROS (p=0.9987, n=8 replicates). In addition, 50uM ethylene glycol‐bis (β‐aminoethyl ether)‐N,N,N′,N′‐tetraacetic acid‐acetoxymethyl ester (EGTA‐AM) failed to prevent EPI‐induced ROS increase (p=0.9768, n=8 replicates). These results might be limited by the technical challenge such as DHE not able to quantitatively distinguish intracellular ROS levels and EGTA‐AM might not be fast enough to chelate Ca 2+ from Ca 2+ influx. Ongoing project will seek to overcome the technical limitation to further test the role of SOCE in EPI‐induced acute cardiotoxicity. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .