Background Anticancer
therapies have significantly improved patient outcomes; however, cardiac side effects from
cancer therapies remain a significant challenge.
Cardiotoxicity following treatment with
proteasome inhibitors such as
carfilzomib is known in clinical settings, but the underlying mechanisms have not been fully elucidated. Methods and Results Using human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) as a cell model for drug-induced cytotoxicity in combination with
traction force microscopy, functional assessments, high-throughput imaging, and comprehensive omic analyses, we examined the molecular mechanisms involved in structural and functional alterations induced by
carfilzomib in hiPSC-CMs. Following the treatment of hiPSC-CMs with
carfilzomib at 0.01 to 10 µmol/L, we observed a concentration-dependent increase in
carfilzomib-induced toxicity and corresponding morphological, structural, and functional changes.
Carfilzomib treatment reduced mitochondrial membrane potential,
ATP production, and mitochondrial oxidative respiration and increased mitochondrial oxidative stress. In addition,
carfilzomib treatment affected contractility of hiPSC-CMs in 3-dimensional microtissues. At a single cell level,
carfilzomib treatment impaired Ca2+ transients and reduced
integrin-mediated
traction forces as detected by piconewton tension sensors. Transcriptomic and proteomic analyses revealed that
carfilzomib treatment downregulated the expression of genes involved in extracellular matrices,
integrin complex, and cardiac contraction, and upregulated stress responsive
proteins including
heat shock proteins. Conclusions
Carfilzomib treatment causes deleterious changes in cellular and functional characteristics of hiPSC-CMs. Insights into these changes could be gained from the changes in the expression of genes and
proteins identified from our omic analyses.