Upregulation of lactate dehydrogenase A by ErbB2 through heat shock factor 1 promotes breast cancer cell glycolysis and growth

Abstract

ErbB2 has been shown to activate signaling molecules that may regulate glucose metabolism. However, there is no evidence reported to directly link ErbB2 to glycolysis, and the mechanism underlying ErbB2-enhanced glycolysis is poorly understood. In this study, we investigated the role and mechanism of ErbB2 in regulating glycolysis. We found that ErbB2-overexpressing cells possessed a significantly higher level of glycolysis when compared to the ErbB2-low-expressing cells, and the downregulation of ErbB2 markedly decreased glycolysis. Overexpression of ErbB2 increased the expression of glycolysis-regulating molecules lactate dehydrogenase A (LDH-A) and heat shock factor 1 (HSF1). ErbB2 activated HSF1, indicated by the increased HSF1 trimer formation, and promoted HSF1 protein synthesis. HSF1 bound to LDH-A promoter and the downregulation of HSF1 reduced the expression of LDH-A and subsequently decreased cancer cell glycolysis and growth. Moreover, the glycolysis inhibitors, 2-deoxyglucose and oxamate, selectively inhibited the growth of ErbB2-overexpressing cells. Taken together, this study shows that in human breast cancer cells, ErbB2 promotes glycolysis at least partially through the HSF1-mediated upregulation of LDH-A. This pathway may have a major role in regulating glucose metabolism in breast cancer cells. These novel findings have important implications for the design of new approaches to target ErbB2-overexpressing breast cancers.