Spatial Heterogeneity and Oxygen Dependence of Glucose Consumption in R3230Ac and Fibrosarcomas of the Fischer 344 Rat

Abstract

To examine the oxygen-dependence of glucose consumption in solid tumors, we monitored gradients of glucose, lactate, and hypoxia in R3230Ac and FSA tumors growing in Fischer 344 rats. Bioluminescence imaging, detection of Hoechst 33342, and immunostaining of the hypoxia marker EF5 [2-8-N-(2,2,3,3,3-pentafluoropropyl)acetamide] were done in serial tumor slices. Glucose and lactate levels were also determined in liver and blood. Cells were further tested for glucose consumption and lactate production in vitro. In both tumor types, EF5 staining indicated similar maximum levels of hypoxia; the most intense staining occurred in perinecrotic regions. Glucose concentrations were highest in liver, declined from blood to tumor edge, further into vital tumor regions, and were lowest close to necrosis. Glucose was significantly lower in FSA than in R3230Ac tumors. Glucose concentrations in R3230Ac tumors were consistently higher in nonhypoxic than in hypoxic areas, with maximum values equal to systemic blood levels. Glucose in FSA tumors was close to zero, regardless of the presence or absence of hypoxia. Lactate did not differ significantly between the tumor types. FSA cells in culture showed a trend towards higher aerobic glucose consumption versus R3230Ac. Both cell lines increased their lactate production to similar levels under hypoxia. We conclude that both R3230Ac and FSA tumors retain the Pasteur effect, i.e., hypoxia triggers increased glycolysis. However, our results imply that increased aerobic glucose utilization leads to low glucose levels in FSA and a situation where supply limits uptake. This explains the repeatedly observed correlation between tumor blood flow and 18 Fdeoxyglucose uptake. (Cancer Res 2005; 65(12): 5163-71)

In vivo multiphoton microscopy of NADH and FAD redox states, fluorescence lifetimes, and cellular morphology in precancerous epithelia

“…Under hypoxic conditions, cells favor glycolysis over oxidative phosphorylation for ATP production. Neoplastic cells also favor glycolysis over oxidative phosphorylation (1,28), so the measured decreases in NADH lifetimes and the contribution of protein-bound NADH with precancer are consistent with the increased levels of glycolysis that are expected in neoplastic cells. Changes in the distribution of NADH enzyme binding sites associated with preferred metabolic pathways in neoplastic tissues (6) may be responsible for the change in protein-bound NADH lifetime with precancer.…”

Aerobic glycolysis in cancers: Implications for the usability of oxygen‐responsive genes and fluorodeoxyglucose‐PET as markers of tissue hypoxia

“…Doing an analysis very similar to ours, Pugachev et al 13 demonstrated a highly significant positive spatial correlation (r 5 0.50-0.66) between the distribution of 18 F-FDG and pimonidazole in the rat prostate cell line R-3327-AT, but this cell type may, as SiHa, be an outlier with a particularly high dependency on mitochondria-derived ATP (i.e., a large Pasteur effect is expected). In contrast, Schroeder et al 25 suggested than even in cells retaining a significant Pasteur effect in vitro, areas of viable hypoxic cells and low glucose uptake may coexist in the tumor, because hypoxic cells may be partly glucose starved. This could possibly explain areas of hypoxia, but with relatively low 18 F-FDG uptake in UT-SCC-33 (Fig.…”

Her2/neu signaling blockade improves tumor oxygenation in a multifactorial fashion in Her2/neu+ tumors

“…This may reflect a lowered capacity to switch from aerobic to anaerobic metabolism, resulting in lower threshold for cell death [26]. We have shown previously that both oxygen and glucose gradients contribute to nutrient depletion and necrosis [27]. Additional studies to examine nutrient gradients in these tumor models might yield mechanistic information underlying the contribution of nutrient depletion to necrosis.…”