African Americans show a 3-fold higher risk of doxorubicin-cardiotoxicity than their White counterparts. Oxidative stress is a major underlying mechanism of dox-cardiotoxicity and is significantly aggravated in African American compared to their white counterparts suggesting a role in dox cardiotoxicity racial disparities. Our preliminary data identified EPHA2.AS1 as a novel gene that might regulate dox-cardiotoxicity. Importantly, race-specific SNPs in EPHA2-AS1 are associated with altered EPHA2 expression, calcium levels, and hepatic inflammatory markers. EPHA2.AS1 is located on the antisense strand adjacent to EPH receptor A2 (EPHA2). EPHA2 promotes mitochondrial dysregulation and oxidative stress and is upregulated during the pathogenesis of multiple diseases. Therefore, we hvaothesize that heart cells generated from African Americans are more p_rone to severe dox-induced cardiotoxicity than White Americans due to altered oxidative stress cardiac regulation and that EPHA2.AS1 regulates EPHA2 in the human heart, which dvsregulates cardiac mitochondria, exacerbating dox-induced cardiotoxicity. We will use a cohort of patient-specific human induced pluripotent stem cell-cardiomyocytes derived from African and White Americans with and without dox-cardiotoxicity to examine ROS production, investigate their effect on dox-cardiotoxicity using our well-established biochemical and functional assays, reveal genes/pathways implicating their race-specific cardiac regulation using RNA-Seq, and screen for cardioprotective antioxidants in iPSC-cardiomyocytes and mice (Aim1). In Alm 2, we will define the role of EPHA2.AS1 in mitochondrial dysregulation-driven dox-cardiotoxicity racial disparities. We will use CRISPR-Cas9-generated EPHA2.AS1 KO, OE, and isogenic iPSC-cardiomyocytes to assess its effect on the severity of dox-cardiotoxicity and on EPHA2 regulation and signaling. Furthermore, we will use CRIPSR-Cas9 to introduce potential candidate EPHA2.AS1 race-specific SNPs in isogenic iPSC-cardiomyocytes followed by characterization of mitochondria dysregulation-driven dox-cardiotoxicity. Moreover, we will use an Epha2 KO mouse to assess the implication of Epha2 in dox-cardiotoxicity in vivo.