Downregulation of Alox5 Inhibits Ferroptosis to Improve Doxorubicin-Induced Cardiotoxicity via the P53/SLC7A11 Pathway.

Doxorubicin (DOX) is an anthracycline chemotherapeutic drug used for tumour treatment. Due to DOX-induced cardiotoxicity (DIC), its clinical application has been widely limited. Multiple studies have shown that ferroptosis is involved in the pathogenesis of DIC and that arachidonate 5-lipoxygenase (Alox5) plays an important role in the occurrence and development of ferroptosis. The aim of this study was to provide evidence that silencing Alox5 alleviated DIC by affecting ferroptosis and identify mechanisms. Acute models of DIC were established in wild-type (WT) C57BL/6 and Alox5-deficient (Alox5 KO) mice and neonatal rat ventricular myocytes (NRVMs). Alox5 was upregulated in vivo and in vitro during DIC. Subsequently, we overexpressed the Alox5 gene in adult mice using a recombinant adenovirus expression vector (rAAV9). Compared with that in WT mice, overexpressing Alox5 accelerated DOX-induced myocardial injury and cardiac dysfunction. This finding was also confirmed in vitro. In contrast, silencing the Alox5 gene protected against myocardial injury in the DIC model and reduced ferroptosis and inflammation, and this effect was confirmed in vitro. In addition, transcriptomics and GO enrichment analysis of adult mouse cardiomyocytes showed that Alox5 could ameliorate DIC by inhibiting ferroptosis and inflammation. Moreover, P53 was identified as a target of Alox5. Subsequently, in vivo and in vitro experiments showed that silencing Alox5 could alleviate ferroptosis and inflammation. Further in vivo and in vitro experiments demonstrated that dexrazoxane (DXZ) could ameliorate DIC caused by Alox5 overexpression by alleviating ferroptosis. Mechanistically, silencing Alox5 could reduce reactive oxygen species (ROS) production through the P53/SLC7A11 pathway. Furthermore, P53 inhibitors significantly inhibited the adverse effects of Alox5 overexpression on DIC. The final experiment showed that pharmacological inhibition of Alox5 could prevent DIC in vivo and in vitro. Our study showed that the downregulation of Alox5 alleviated myocardial damage associated with DIC via the P53/SLC7A11 pathway. Therefore, inhibiting Alox5 might be a potential strategy for the treatment of DIC.