Astemizole Exacerbates 5-Fluorouracil-Triggered Cardiotoxicity by Enhancing Ptgs2

5-fluorouracil (5-FU), a commonly utilized antitumor agent for the treatment of colon cancer, is linked to an increased risk of cardiovascular diseases. Antihistamines including astemizole (AST) have been reported to present cardiovascular toxicity; however, it remains unclear how 5-FU-mediated cardiotoxicity is affected by AST during the treatment of colon cancer. This study explored the role of AST in 5-FU-induced cardiotoxicity in colon cancer. 5-FU was used to induce cardiotoxicity in cardiomyocytes (HL-1 cells) and BALBc mice, creating in vitro and in vivo models of chemotherapeutic drug-induced cardiotoxicity. In the mice model, we found that the blocking of histamine signal by AST aggravated 5-FU-induced cardiac function injury and cardiac fibrosis. In HL-1 cardiomyocyte cells, the increases of apoptosis and generation of mitochondrial reactive oxygen species (mtROS) were evaluated after the combination treatment of AST and 5-FU. Proinflammatory M1-like-type macrophages were dominant in the AST and 5-FU combination group compared to control groups. The protein expression of prostaglandin-endoperoxide synthase 2 (Ptgs2) was assessed both in vitro and in vivo using Western blot analysis. Clinically, altered Ptgs2 was closely associated with adverse cardiovascular outcomes. Overall, the combination of AST and 5-FU significantly enhanced cardiotoxicity by inducing cardiomyocyte apoptosis, inflammation, and the expression of Ptgs2.