Figure 3
Glucose metabolic phenotypes of cancer cells with ample oxygen dictated by lactate and proton. (a) Under regular culture, cancer cells show highest glycolysis rate, convert about 85% glucose to lactate and about 10% to carbon dioxide and water. (b) Under lactic acidosis, cancer cells exhibit lowest glycolysis rate (20% of the one under regular culture), convert 40% glucose to carbon dioxide and water and produce no or negligible lactate as LDH-catalyzed reaction is at near equilibrium, hence NADH generated from glycolysis is presumably cycled back to NAD through malate-aspartate or glycerol 3-phosphate shuttle that conveys cytosolic NADH to mitochondria for oxidation. (c) Under acidosis, glycolysis rate is about 30% of the one under regular culture and cells coverts about 80% glucose to lactate. (d) Under lactosis, glycolysis rate is about 85% of the one under regular culture; cells convert about 60% glucose to lactate. pHe, extracellular pH; pHi, intracellular pH; lactate (e), extracellular lactate concentration; lactate (i), intracellular lactate concentration. The data are generated from 4T1 cells.30,45 The switch between phenotypes is observed in all other tested cells, including Bcap37, HepG2, HeLa, A549, H1299, SKBR3, SW620, SiHa, RKO, SGC7901, MCF-7, HCT116, with no exception.
