Lactate Dehydrogenase A (LDH-A) May Not Be Primarily Responsible for Maintaining High Tumor Lactic Acid Levels in Aggressive Breast Cancer

A well-known characteristic of tumor cells is the propensity to produce excessive amounts of lactic acid when deprived of normal levels of oxygen, and also when exposed to normal oxygen levels, also referred to as the Warburg effect. High levels of lactate are believed to be associated with elevated expression of lactate dehydrogenase A (LDHA), a protein up-regulated in diverse aggressive malignancies. In this study, shRNAs were used to permanently knock down the expression of LDHA in human MDA-MB 231 and MDA-MB 468 cells. LDHA knockdown was confirmed by both Western Blot and qPCR. Furthermore, metabolic analysis included assessment of changes in cell viability, glucose utilization, lactate levels and cellular energy production by quantification of ATP. Silencing of the LDHA gene and protein had no effect on lactate production, glucose utilization, cellular metabolic activity and ATP in MDA-MB 231 and MDA-MB 468 tumor cells. These findings show no relationship between LDH-A expression in both cells lines ...