Mitochondria-dependent ferroptosis plays a pivotal role in doxorubicin cardiotoxicity

TLDR

Doxorubicin causes dose‑dependent cardiomyopathy that limits therapy and worsens prognosis, yet its molecular basis remains incompletely understood. The study aims to demonstrate that doxorubicin induces mitochondria‑dependent ferroptosis by downregulating GPx4 and promoting lipid peroxidation via a DOX‑Fe²⁺ complex, establishing this pathway as a major driver of cardiotoxicity. Doxorubicin‑Fe²⁺ complexes in mitochondria trigger lipid peroxidation and ferroptosis, which is prevented by GPx4 overexpression or mitochondrial iron chelation, and fully abrogated when ferroptosis and apoptosis are simultaneously inhibited with ferrostatin‑1 and zVAD‑FMK. In mice, doxorubicin impaired ejection fraction, induced fibrosis and TUNEL⁺ cells, and downregulated GPx4 with mitochondrial lipid peroxide accumulation; GPx4 transgenic mice were protected while heterodeletion worsened injury, confirming mitochondria‑dependent ferroptosis as the principal form of regulated cell death in doxorubicin cardiotoxicity.

Abstract

Doxorubicin (DOX), a chemotherapeutic agent, induces a cardiotoxicity referred to as doxorubicin-induced cardiomyopathy (DIC). This cardiotoxicity often limits chemotherapy for malignancies and is associated with poor prognosis. However, the molecular mechanism underlying this cardiotoxicity is yet to be fully elucidated. Here, we show that DOX downregulated glutathione peroxidase 4 (GPx4) and induced excessive lipid peroxidation through DOX-Fe2+ complex in mitochondria, leading to mitochondria-dependent ferroptosis; we also show that mitochondria-dependent ferroptosis is a major cause of DOX cardiotoxicity. In DIC mice, the left ventricular ejection fraction was significantly impaired, and fibrosis and TUNEL+ cells were induced at day 14. Additionally, GPx4, an endogenous regulator of ferroptosis, was downregulated, accompanied by the accumulation of lipid peroxides, especially in mitochondria. These cardiac impairments were ameliorated in GPx4 Tg mice and exacerbated in GPx4 heterodeletion mice. In cultured cardiomyocytes, GPx4 overexpression or iron chelation targeting Fe2+ in mitochondria prevented DOX-induced ferroptosis, demonstrating that DOX triggered ferroptosis in mitochondria. Furthermore, concomitant inhibition of ferroptosis and apoptosis with ferrostatin-1 and zVAD-FMK fully prevented DOX-induced cardiomyocyte death. Our findings suggest that mitochondria-dependent ferroptosis plays a key role in progression of DIC and that ferroptosis is the major form of regulated cell death in DOX cardiotoxicity.