ABSTRACT The nuclear factor (NF)-B signaling pathway is an important intracellular mediator of cardiac hypertrophy. The aim of the present study was to determine whether triflusal (2-acetoxy-4-trifluoromethylbenzoic acid), a salicylate derivative used as antiplatelet agent, and its active metabolite 2-hydroxy-4-trifluoromethylbenzoic acid (HTB) inhibit cardiac hypertrophy in vitro and in vivo by blocking the NF-B signaling pathway. In cultured neonatal rat cardiomyocytes, HTB (300 M, a concentration reached in clinical use) inhibited phenylephrine (PE)-induced protein synthesis ([ 3 H]leucine uptake), induction of the fetal-type gene atrial natriuretic factor (ANF), and sarcomeric disorganization. Assessment of the effects of triflusal in pressure overload-induced cardiac hypertrophy by aortic banding resulted in a significant reduction in the ratio of heart weight to body weight and in a reduction of the mRNA levels of the cardiac hypertrophy markers ANF and ␣-actinin compared with untreated banded rats. Electrophoretic mobility shift assay revealed an increase in the NF-B binding activity in cardiac nuclear extracts of banded rats that was prevented by triflusal treatment. It is noteworthy that banded rats treated with oral triflusal, compared with untreated rats, showed enhanced protein levels of IB␣, which forms a cytoplasmic inactive complex with the p65-p50 heterodimeric complex. Finally, HTB increased phospho-IB␣ levels in neonatal cardiomyocytes and inhibited proteosome activity, suggesting that this drug prevented proteosome-mediated degradation of IB␣. These results indicate that triflusal, a drug with a well characterized pharmacological and safety profile currently used as antiplatelet, inhibits cardiomyocyte growth by interfering with the NF-B signaling pathway through a post-transcriptional mechanism involving reduced-proteosome degradation of IB␣. Cardiac hypertrophy is a response of the heart to a wide range of extrinsic stimuli, such as arterial hypertension, valvular heart disease, myocardial infarction, and cardiomyopathy. Although this process is initially compensatory for an increase workload, its prolongation frequently results in congestive heart failure, arrhythmia, and sudden deat
