Evaluating the Role of Protein O-GlcNAcylation in the Pathophysiology of Anthracycline-Induced Cardiotoxicity

Introduction Anthracyclines, including doxorubicin (DOX), are highly effective chemotherapeutic agents, but their clinical use is hampered by late-onset cardiotoxicity, driven by poorly understood molecular mechanisms. Recently, metabolic impairments have been identified as a central feature of DOX-induced cardiotoxicity. Protein O-GlcNAcylation is a glucose-derived post-translational modification produced via the hexosamine biosynthetic pathway that couples nutrient availability to adaptive stress signalling during heart failure progression. Objective Here, we investigated whether protein O-GlcNAcylation is modified by DOX and could contribute to DOX-induced cardiotoxicity (DIC). Method C57BL/6N mice received DOX (4mg/kg) via 6 intraperitoneal injections over 2 weeks (cumulative dose 24mg/kg). Cardiac function was evaluated at baseline and 6 weeks after the first injection. In vitro, adult rat ventricular myocytes (ARVMs) were treated with DOX along with O-GlcNAc inhibitors (DON and AMPK agonists) and inducer (Thiamet-G) to modulate the O-GlcNAcylation pathway. Modulation of protein O-GlcNAcylation and of its regulatory enzymes (GFAT, OGT, and OGA), as well as AMPK activation were evaluated by western blot. Apoptosis was evaluated by examining the caspase-3 cleavage. Results Echocardiography revealed systolic dysfunction and cardiac atrophy 6 weeks after treatment, associated with increased cardiac protein O-GlcNAcylation. In ARVMs, DOX treatment promoted apoptosis and induced a dose- and time-dependent enhancement of protein O-GlcNAcylation, accompanied by reduced levels of OGA, the sole enzyme responsible for removing O-GlcNAc modifications, and by a decrease in AMPK signalling (reduced phosphoAMPK/AMPK ratio), known to negatively regulate O-GlcNAcylation. Pharmacological inhibition of O-GlcNAcylation (using DON or the AMPK agonist 991) attenuated DOX-induced apoptosis, while its stimulation (with Thiamet-G) promoted ARVM apoptosis. Conclusion Our findings implicate O-GlcNAcylation in DIC and highlight AMPK activation as a promising therapeutic avenue.