Doxorubicin (DOX), an anthracycline antitumor agent, exhibits profound efficacy across diverse tumor types. Nonetheless, the breadth of its systemic adverse effects has constrained its broad application in cancer chemotherapy [[1], [2], [3]]. Despite its status as the foremost antitumor medication in clinical practice, doxorubicin remains encumbered by the heightened risk of cardiotoxicity, posing a significant challenge for cancer patients undergoing treatment [4]. Mitochondria serve as the primary intracellular source of reactive oxygen species (ROS). In the event of mitochondrial dysfunction, an excessive accumulation of ROS can initiate oxidative stress, resulting in detrimental effects on vital biological macromolecules, including lipids, proteins, and DNA. This oxidative damage ultimately culminates in the disruption of cellular membrane integrity and functionality [5]. DOX disrupts the normal electron transport chain within mitochondria, resulting in an elevated production of free radicals. This excessive generation of free radicals directly elicits oxidative stress damage in cardiomyocytes, thereby further promoting the generation of reactive oxygen species (ROS) [6]. DOX stimulates the release of inflammatory mediators and disrupts the homeostasis of intracellular calcium cycling in cardiac cells. Consequently, this triggers apoptotic signaling pathways, ultimately leading to cardiomyocyte apoptosis and exacerbating the cardiac toxicity associated with DOX administration [7]. Acute cardiotoxicity can swiftly emerge within a few days of commencing doxorubicin treatment, prominently marked by a notable decrease in myocardial contractility [8]. Doxorubicin can induce cardiotoxicity through heightened protein degradation and the down-regulation of proteins associated with critical cellular components, including the sarcoplasmic ganglia, contractile apparatus, mitochondria, and sarcoplasmic reticulum [9]. Doxorubicin (DOX) additionally fosters the production of reactive oxygen species (ROS) and instigates DNA damage, thereby precipitating the demise of cardiomyocytes. It has been hypothesized that doxorubicin induces cardiotoxicity through redox cycling mechanisms, thereby engendering a surge in ROS generation [10,11]. The dysfunction and apoptotic demise of cardiomyocytes induced by doxorubicin precipitate cardiac remodeling [12], accompanied by an aberrant accumulation of collagen types I and III, culminating in cardiac fibrosis [13]. Doxorubicin-induced effects such as hypertrophy, dilatation, cardiomyopathy, and diminished contractile strength precipitate myocardial dysfunction, ultimately leading to heart failure [14,15]. While the issue of doxorubicin-induced cardiotoxicity has garnered considerable attention in recent years, the availability of pertinent therapeutic strategies remains limited. Consequently, there exists a pressing need for the continued development of novel therapeutic agents aimed at ameliorating the cardiotoxic effects of doxorubicin therapy.

Ubiquitination, a pivotal post-translational modification, intricately regulates various cell death pathways, encompassing programmed cell death modalities such as apoptosis, necroptosis, pyroptosis, and ferroptosis, alongside vital cellular signaling cascades and other essential biological processes [16,17]. Additionally, ubiquitination plays a crucial role in modulating inflammatory responses, further underscoring its multifaceted involvement in the orchestration of cellular homeostasis and immune regulation [18]. Ubiquitination, akin to neddylation, constitutes a process of post-translational protein modification whereby the neuronal precursor cell-expressed developmental down-regulated protein 8 (NEDD8) binds to target proteins, thereby exerting regulatory control over their functional properties [[19], [20], [21]]. This intricate process is orchestrated by the NEDD8-activating enzyme E1, comprising NAE1 and UBA3 subunits, alongside the NEDD8-catalyzed conjugating enzyme E2, UBC12, and the NEDD8 E3 ligase. Together, these enzymatic components facilitate the precise conjugation of NEDD8 to target proteins, thereby modulating their biological functions [21]. The binding of NEDD8 to cullins triggers the activation of CRL (Cullin-RING Ligase) complexes, thus initiating a cascade of events crucial for the regulation of protein degradation and cellular homeostasis [20,22]. CRL-mediated ubiquitination targets a diverse array of proteins for degradation, thus exerting profound regulatory influence over numerous cellular processes and pathways [23]. Functionally, the neddylation pathway assumes a pivotal role in the proteasomal degradation of a myriad of proteins intricately involved in cell cycle regulation, DNA replication, and apoptotic biological activities [24]. Current research has demonstrated that dysregulation of neddylation can modulate the function and survival of cardiomyocytes, thereby conferring significant scientific importance and practical value to its investigation in the context of cardiac biology [25]. MLN4924, an inhibitor of the NEDD8-activating enzyme (NAE), exerts profound anticancer effects by disrupting neddylation, thereby eliciting apoptosis [26], senescence, and autophagy in tumor cells [[27], [28], [29]]. MLN4924 also plays a pivotal role in modulating the inflammatory response by attenuating lipopolysaccharide (LPS)-induced production of pro-inflammatory cytokines such as TNF-α and IL-6, while preserving cellular viability to a significant degree [30]. Previous research has demonstrated that MLN4924 can ameliorate fibrosis in both hepatic and pulmonary tissues [31]. In the realm of cardiovascular diseases, studies have revealed the potent cardioprotective effects of MLN4924. By bolstering cell viability, this compound mitigates left ventricular contractile dysfunction and consequently restricts infarct size in mice subjected to myocardial ischemia/reperfusion (MI/R) [32]. A recent study has reported that the neddylation inhibitor MLN4924 also mitigates cerebral infarction and enhances neurological functions [33]. MLN4924 induces apoptosis in vascular endothelial cells through the p53/p62 pathway and mitigates neointimal hyperplasia following mechanical vascular injury in mice. These results underscore the potential of neddylation modulation as a promising therapeutic approach for the management of restenosis [34]. However, to the best of our knowledge, the involvement of neddylation in doxorubicin-induced cardiotoxicity has not yet been fully elucidated.

In this study, utilizing a mouse model of acute doxorubicin-induced myocardial injury, we observed an up-regulation of neddylation in the myocardium, commencing on day 1 post-drug administration and peaking significantly by day 5. Remarkably, treatment with the neddylation inhibitor MLN4924 yielded promising outcomes, notably reducing myocardial injury, averting cardiac atrophy, preserving mitochondrial function, shielding against cellular oxidative stress, and diminishing cardiomyocyte apoptosis. Consequently, MLN4924 exhibited a remarkable capacity to enhance cardiac contractile function and bolster survival rates in mice. These cardioprotective effects of MLN4924 were attributed to its ability to mitigate the deleterious effects of heightened neddylation activity through the inhibition of the NEDD8-activating enzyme (NAE).