Cardiac atrophy, dysfunction, and metabolic impairments: a cancer-induced heart failure phenotype

Muscle atrophy and weakness are prevalent features of cancer. While extensive research has characterized skeletal muscle wasting in cancer cachexia, limited studies have investigated how cardiac structure and function are affected by therapy-naive cancer. In cell-based models of orthotopic, syngeneic epithelial ovarian cancer (EOC) and pancreatic ductal adenocarcinoma (PDAC), and a patient-derived pancreatic xenograft model (PDX), we evaluated cardiac structure, function, and metabolism. Tumor-bearing mice showed cardiac atrophy and intrinsic systolic and diastolic dysfunction; associated with hypotension and exercise intolerance. In hearts of ovarian tumor-bearing mice, fatty acid-supported mitochondrial respiration decreased and carbohydrate-supported respiration increased, establishing a substrate shift in cardiac metabolism that is characteristic of heart failure. EOC decreased cytoskeletal and cardioprotective gene expression, which was paralleled by downregulation of transcription factors that regulate cardiomyocyte size and function. PDX tumors altered myosin heavy chain isoform expression - a molecular phenotype observed in heart failure. Markers of autophagy and ubiquitin-proteasome system were upregulated with cancer, providing evidence of catabolic signaling that promotes cardiac wasting. Together, metabolic stress, cardiac gene dysregulation, and upregulation of catabolic pathways contribute to cardiac atrophy and failure during cancer. Finally, we demonstrate that pathological cardiac remodeling is induced by human cancer, providing translational evidence of cancer-induced cardiomyopathy.