Empagliflozin attenuates trastuzumab-induced cardiotoxicity through suppression of DNA damage and ferroptosis

Trastuzumab (TZM) is commonly used for target therapy in breast cancer patients with high HER2 although the cardiotoxicity restricts its clinical usage. DNA damage and ferroptosis are implicated in anti-tumor drug cardiotoxicity. Given the emerging use of SGLT2 inhibitors in clinical cardiology, this study evaluated the impact of SGLT2 inhibitor Empagliflozin on TZM-induced cardiotoxicity, and mechanism involved with a focus on DNA damage and ferroptosis. Adult C57BL/6 mice were challenged with TZM (10 mg/kg/week, i.p.) or saline for six weeks. A cohort of mice received Empagliflozin (10 mg/kg, i.p.) at the same time. Myocardial function, morphology, ultrastructure, mitochondrial integrity, oxidative stress, DNA damage and various cell death domains were evaluated in TZM-challenged mice with or without Empagliflozin treatment. Our data revealed that TZM challenge overtly increased levels of serum LDH and troponin I, promoted adverse myocardial remodeling (increased heart weight, chamber size, cardiomyocyte area and interstitial fibrosis), contractile dysfunction and intracellular Ca2+ mishandling, oxidative stress, lipid peroxidation, mitochondrial ultrastructural damage, DNA damage, apoptosis and ferroptosis, the effects of which were greatly attenuated or mitigated by Empagliflozin with little effects from Empagliflozin itself. In vitro study indicated that induction of DNA damage mimicked TZM-induced lipid peroxidation and cardiomyocyte contractile dysfunction while the ferroptosis inducer erastin mitigated Empagliflozin-offered protection against lipid peroxidation and cardiomyocyte dysfunction (but not DNA damage). Likewise, in vivo and in vitro inhibition of ferroptosis recapitulated Empagliflozin-offered cardioprotection against TZM exposure. Taken together, these data demonstrated that Empagliflozin may be possible candidate drug for TZM cardiotoxicity likely through a DNA damage-ferroptosis-mediated mechanism.