Trastuzumab potentiates doxorubicin-induced cardiotoxicity via activating the NLRP3 inflammasome in vivo and in vitro.

Trastuzumab (Tra), the first humanized monoclonal antibody that targets human epidermal growth factor receptor 2 (HER2), is commonly used alongside doxorubicin (Dox) as a combination therapy in HER2-positive breast cancer. Unfortunately, this leads to a more severe cardiotoxicity than Dox alone. NLRP3 inflammasome is known to be involved in Dox-induced cardiotoxicity and multiple cardiovascular diseases. However, whether the NLRP3 inflammasome contributes to the synergistic cardiotoxicity of Tra has not been elucidated. In this study, primary neonatal rat cardiomyocyte (PNRC), H9c2 cells and mice were treated with Dox (15 mg/kg in mice or 1 μM in cardiomyocyte) or Tra (15.75 mg/kg in mice or 1 μM in cardiomyocyte), or Dox combined Tra as cardiotoxicity models to investigate this question. Our results demonstrated that Tra significantly potentiated Dox-induced cardiomyocyte apoptosis and cardiac dysfunction. These were accompanied by the increased expressions of NLRP3 inflammasome components (NLRP3, ASC and cleaved caspase-1), the secretion of IL-β and the pronounced production of ROS. Inhibiting the activation of NLRP3 inflammasome by NLRP3 silencing significantly reduced cell apoptosis and ROS production in Dox combined Tra-treated PNRC. Compared with the wild type mice, the systolic dysfunction, myocardial hypertrophy, cardiomyocyte apoptosis and oxidative stress induced by Dox combined Tra were alleviated in NLRP3 gene knockout mice. Our data revealed that the co-activation of NLRP3 inflammasome by Tra promoted the inflammation, oxidative stress and cardiomyocytes apoptosis in Dox combined Tra-induced cardiotoxicity model both in vivo and in vitro. Our results suggest that NLRP3 inhibition is a promising cardioprotective strategy in Dox/Tra combination therapy.