Involvement of Monocarboxylate Transporter 4 Expression in Statin-Induced Cytotoxicity

Statins, 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, are the most widely used cholesterol-lowering agents for prevention of obstructive cardiovascular events. However, statins can cause a variety of skeletal muscle problems, and exercise leads to an increase in statin-induced muscle injury. Exercise induces the protein content of monocarboxylate transporter 4 (MCT4), which is expressed strongly in skeletal muscle and is thought to play a major role in the transport of metabolically important monocarboxylates such as l-lactate. We previously reported that α-cyano-4-hydroxycinnamate, an MCT4 inhibitor, increased the inhibition of growth of RD cells, a prototypic embryonal rhabdomyosarcoma cell line (an RD cell line), as a model of in vitro skeletal muscle, induced by a statin. However, it is unclear whether statin-induced RD cell cytotoxicity is associated with MCT4 expression. We, therefore, examined the relationship between statin-induced cytotoxicity and MCT4 expression in RD cells. Atorvastatin reduced the number of viable cells and upregulated MCT4, but not MCT1, mRNA level in a concentration-dependent manner. MCT4 knockdown suppressed atorvastatin-, simvastatin-, and fluvastatin-induced reduction of cell viability and apoptosis compared with negative control-treated cells. In this study, we demonstrated that MCT4 expression is associated with statin-induced cytotoxicity.