Abstract 787: Multi-omics approach to delineate the mechanisms of doxorubicin-induced cardiotoxicity

Introduction: Doxorubicin (DOX) is a highly effective chemotherapeutic agent utilized in the treatment of a wide variety of adult and pediatric malignancies. However, the clinical utility of DOX is limited by its cardiotoxicity. Mechanisms of DOX-induced cardiotoxicity are not fully elucidated, highlighting the need for comprehensive studies. Proteomic and transcriptomic analyses provide an unbiased platform to uncover the molecular pathways underlying drug-induced toxicity. The objective of the current work is to delineate the mechanisms of DOX-induced chronic cardiotoxicity in C57BL/6N mice using a multi-omics approach to identify key molecular pathways and potential therapeutic targets. Methods: Five-week-old C57BL/6N mice were randomized to receive six weekly intraperitoneal injections of either DOX (4 mg/kg/week for 6 weeks) or saline. Three days following the last injection, cardiac function was assessed by trans-thoracic echocardiography. Cardiac proteomic profiling and RNA sequencing were performed using pulverized heart tissues to determine the underlying molecular mechanisms of DOX-induced cardiotoxicity. Identified differentially expressed proteins and genes were validated by western blotting and quantitative real-time PCR, respectively. Key protein biomarkers were measured in plasma samples from breast cancer patients treated with doxorubicin using ELISA. To contextualize our findings, we also compared our data with multiple publicly available proteomic and RNA-sequencing datasets. Results and Conclusion: DOX treatment induced cardiac dysfunction, evidenced by reductions in left ventricular fraction and fractional shortening. Proteomic analysis of heart tissue identified key proteins related to cardiotoxicity, including serpina3n, thrombospondin-1, and epoxide hydroxylase 1, all of which were significantly upregulated. RNA sequencing revealed the upregulation of Nr1d1, Phlda3, sestrin2 (sesn2), lipocalin2 (Lcn2), and Trp53inp1, with a downregulation of apelin-1. Protein expressions of serpina3n, and thrombospondin-1 were confirmed by immunoblotting, and gene expressions of Nr1d1, Trp53inp1, sestrin2, epoxide hydroxylase 1, and apelin-1 were confirmed by real-time PCR. Integrative analysis of our proteomics, RNA sequencing and other publicly available datasets identified common molecular pathway involving Nr1d1-serpina3n, underscoring its potential role in DOX-induced cardiotoxicity. Furthermore, plasma levels of serpina3 were significantly elevated in breast cancer patients 24 hours after receiving DOX-based chemotherapy compared to baseline, highlighting translational relevance of these findings. In conclusion, our findings provide valuable insights into the molecular mechanisms underlying DOX-induced cardiotoxicity, which could inform future therapeutic strategies to mitigate its adverse effects. Citation Format: Mohamed S. Dabour, Ibrahim Y. Abdelgawad, Bushra Sadaf, Mary R. Daniel, Marianne K. Grant, Anne H. Blaes, Pamala A. Jacobson, Beshay N. Zordoky. Multi-omics approach to delineate the mechanisms of doxorubicin-induced cardiotoxicity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 787.