Multi-parameter in vitro toxicity testing of crizotinib, sunitinib, erlotinib, and nilotinib in human cardiomyocytes

Tyrosine kinase inhibitors (TKi) have greatly improved the treatment and prognosis of multiple cancer types. However, unexpected cardiotoxicity has arisen in a subset of patients treated with these agents that was not wholly predicted by pre-clinical testing, which centers around animal toxicity studies and inhibition of the human Ether-a-go-go-Related Gene (hERG) channel. Therefore, we sought to determine whether a multi-parameter test panel assessing the effect of drug treatment on cellular, molecular, and electrophysiological endpoints could accurately predict cardiotoxicity. We examined how 4 FDA-approved TKi agents impacted cell viability, apoptosis, reactive oxygen species (ROS) generation, metabolic status, impedance, and ion channel function in human cardiomyocytes. The 3 drugs clinically associated with severe cardiac adverse events (crizotinib, sunitinib, nilotinib) all proved to be cardiotoxic in our in vitro tests while the relatively cardiac-safe drug erlotinib showed only minor changes in cardiac cell health. Crizotinib, an ALK/MET inhibitor, led to increased ROS production, caspase activation, cholesterol accumulation, disruption in cardiac cell beat rate, and blockage of ion channels. The multi-targeted TKi sunitinib showed decreased cardiomyocyte viability, AMPK inhibition, increased lipid accumulation, disrupted beat pattern, and hERG block. Nilotinib, a second generation Bcr-Abl inhibitor, led to increased ROS generation, caspase activation, hERG block, and an arrhythmic beat pattern. Thus, each drug showed a unique toxicity profile that may reflect the multiple mechanisms leading to cardiotoxicity. This study demonstrates that a multi-parameter approach can provide a robust characterization of drug-induced cardiomyocyte damage that can be leveraged to improve drug safety during early phase development.