# Limitations of Ferroptosis Inhibitors on the Doxorubicin-Induced Cardiotoxicity

## TL;DR

This study shows that ferroptosis inhibitors do not prevent heart damage caused by the chemotherapy drug doxorubicin.

## Contribution

The study demonstrates that ferroptosis inhibitors fail to protect cardiomyocytes from doxorubicin-induced toxicity in both cell and animal models.

## Key findings

- Ferroptosis inhibitors rescued cell death caused by RSL3 but not by doxorubicin.
- Ferroptosis inhibitors did not restore electrophysiological function and slightly accelerated cardiomyocyte beating.
- Mice treated with ferroptosis inhibitors showed reduced survival and increased heart failure biomarkers after doxorubicin.

## Abstract

Doxorubicin is an anthracycline anticancer drug commonly used to treat lymphoma and breast cancer. Its major side effect is cardiotoxicity, which occurs by damaging cardiomyocytes. The mechanisms of doxorubicin-induced cardiotoxicity remain unclear; however, recent studies suggest that ferroptosis, an iron-dependent form of lipid peroxidation-mediated cell death, may play a key role. In this study, we investigated the role of ferroptosis in doxorubicin-induced cardiotoxicity using ferroptosis-specific inhibitors (ferrostatin-1 and liproxstatin-1). In both H9c2 cardiomyocyte cell lines and human induced pluripotent stem cell-derived cardiomyocytes, ferrostatin-1 and liproxstatin-1 rescued cell death induced by RSL3, a ferroptosis inducer, but failed to prevent doxorubicin-induced cell death. Additionally, the ferroptosis inhibitors did not restore the electrophysiological function of cardiomyocytes, measured using a multi-electrode array system, and instead slightly accelerated cardiomyocyte beating. Finally, doxorubicin-injected mice treated with ferroptosis inhibitors exhibited significantly reduced survival and increased levels of N-terminal pro B-type natriuretic peptide, a biomarker of heart failure. These findings suggest that inhibiting ferroptosis alone is insufficient to mitigate doxorubicin-induced cardiotoxicity.