EBBP-Mediated Integrated Stress Response Attenuates Anthracycline-Induced Cardiotoxicity by Inhibiting the Ferroptosis of Cardiomyocytes.

Anthracyclines are potent chemotherapeutics, but their clinical application is constrained by dose-dependent cardiotoxicity, in which ferroptosis plays a critical role. Here, EBBP (Estrogen-responsive B Box Protein) is identified as a key cardioprotective regulator in anthracycline-induced cardiotoxicity. Transcriptomic profiling of doxorubicin (DOX)-treated hearts reveals significant EBBP upregulation. Cardiac-specific overexpression of EBBP protects against myocardial injury and dysfunction by reducing DOX-induced ferroptosis. Conversely, EBBP silencing exacerbates DOX-induced cardiac damage, an effect reversed by ferroptosis inhibitor ferrostatin-1 (Fer-1). The molecular targets of EBBP are subsequently identified through bulk RNA sequencing, molecular docking analysis, co-immunoprecipitation experiments, and ubiquitination assays. Mechanistically, EBBP interacts with GRP78 to promote its K63-linked ubiquitination, disrupting the inhibitory GRP78-PERK interaction and activating PERK-mediated integrated stress response (ISR). This signaling cascade ultimately leads to the activation of downstream effectors ATF4 and Nrf2, which coordinately upregulates the SLC7A11/GSH/GPX4 axis and restores iron homeostasis. Importantly, pharmacological inhibition of PERK abolishes the protective effects of EBBP against myocardial injury and ferroptosis. Overall, our findings identify EBBP as a novel suppressor of ferroptosis in anthracycline-induced cardiotoxicity via the PERK-mediated ISR, thereby underscoring its therapeutic potential for preventing anthracycline-induced cardiomyopathy.