Abstract
PURPOSE: Cancer cells depend on glucose metabolism via exclusive glycolysis pathway is named Aerobic glycolysis or Warburg effect. The aim of this study was investigation of different glucose accessibility conditions on the rate of Warburg effect and its impact on Hypoxia inducible factors-1 α (HIF-1 α)/vascular endothelium growth factor (VEGF) pathway in breast cancer cells lines. METHODS: MDA-MB-231 (Warburg phenomenon) and MCF-7 (oxidative) cell lines were cultured in DMEM and exposed to three different glucose accessibility medium for 48 h (5.5 mM as normal glucose (NG), 25 mM as high glucose (HG) and 2-Deoxyglucose (2-DG) as restricted glucose accessibility). Glucose uptake, intra/extracellular lactate and pyruvate, HIF-1α accumulation and vascular endothelium growth factor (VEGF) expression were evaluated by standard methods. RESULTS: Our results showed in NG condition both of cell lines produce lactate, but it was higher in MDA-MB-231. HG condition increased extracellular lactate in both cell lines especially in MCF-7 cells whereas intracellular lactate and pyruvate raised only in MCF-7. 2-DG decreased extracellular and intracellular lactate and pyruvate in both cell lines especially in MDA-MB-231. HIF-1α accumulation was detectable in NG condition in both cell lines. HG condition increased HIF-1α accumulation in MCF-7 cells but not in MDA-MB-231 and 2-DG decreased it in both call lines, especially in MDA-MB-231. Expression of VEGF had similar pattern with HIF-1α in different conditions. CONCLUSIONS: Our findings revealed the rate of Warburg effect is an important indicator for tumor promotion and invasion due to its impacts on important transcription factors like HIF-1α.