Abstract
AIMS: Doxorubicin (Dox) is an effective chemotherapeutic agent, but its clinical use is limited by cardiotoxicity. Cellular senescence contributes to Dox-induced cardiac dysfunction; however, the underlying molecular mechanism mediating the effect of senescence remains poorly understood. This study aimed to identify senescence-associated factors secreted from cardiomyocytes in Dox-treated hearts and define their functional significance in Dox-induced cardiotoxicity. METHODS: Mice with cardiomyocyte-specific expression of the endoplasmic reticulum BioID secretome profiling system were used to identify Dox-induced secreted factors. Functional analyses were performed in neonatal rat ventricular myocytes (NRVMs). The effects of plasminogen activator inhibitor-1 (PAI-1) inhibition were evaluated in Dox-treated mice by assessing senescence markers, apoptotic responses, and cardiac structure and function. p21 (High) -tdTomato reporter mice were used to examine the fate of senescent cardiomyocytes in vivo. RESULTS: PAI-1 was identified as a major component of the senescence-associated secretory phenotype and was robustly upregulated in Dox-treated cardiomyocytes. In NRVMs, PAI-1 promoted senescence and maintained the senescent phenotype, in part by conferring resistance to apoptosis. Pharmacological inhibition of PAI-1 reduced senescence markers, enhanced apoptotic responses, and preserved cardiac structure and function in Dox-treated mice. Fate mapping analyses with p21 (High) -tdTomato mice revealed that PAI-1 inhibition decreased the number of p21 (High) senescent cardiomyocytes in Dox-treated hearts. Notably, PAI-1 inhibition did not attenuate Dox cytotoxicity in EO771 murine breast cancer cells. CONCLUSION: PAI-1 is a key mediator of Dox-induced cardiac dysfunction. PAI-1 inhibition shifts the fate of cardiomyocytes from senescence toward apoptosis and preserves cardiac structure and function without compromising the antitumor function of Dox, highlighting PAI-1 as a potential therapeutic target for chemotherapy-associated cardiotoxicity.