Activation of c-Jun N-terminal kinase is required for mevastatin-induced apoptosis of salivary adenoid cystic carcinoma cells

Abstract

Statins are inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase, originally developed for lowering cholesterol. Statins also have pleiotropic effects, independent of cholesterol-lowering effects, including induction of apoptosis in various cell lines. However, the mechanism underlying statin-induced apoptosis is still not fully understood. This study aims to explore the proapoptotic effects and underlying mechanisms of statins on human salivary adenoid cystic carcinoma (SACC). Exposure of SACC cells to mevastatin resulted in cell growth inhibition and apoptosis in a dose-dependent manner, accompanied by the release of cytochrome c and cleavage of caspase-3. A remarkable decrease in phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) and increase in phosphorylation of c-Jun N-terminal kinase (JNK) and p38 mitogen-activated kinase were observed. Furthermore, the JNK-specific inhibitor SP600125, but not the p38-specific inhibitor SB203580, abolished mevastatin-induced cell growth inhibition and apoptosis in SACC cells. This was supported by results in which the JNK inhibitor efficiently blocked mevastatin-induced JNK phosphorylation, but not p38 phosphorylation, and further decreased mevastatin-induced phosphorylation of ERK1/2. Taken together, the results suggest that the JNK pathway was required for mevastatin-induced cell growth inhibition and apoptosis in SACC cells. Statins could be potential anticancer agents for SACC chemotherapy.