Figure 5. Metabolic characterization of tumor cells.

(A) An astrocyte expressing Laconic was sequentially exposed to 5 mM azide, 50 µM phloretin and 500 µM pCMBS. The straight lines represent initial slopes of lactate accumulation fitted by linear regression within the same range of ratio values. (B) A T98G glioma cell expressing Laconic was sequentially exposed to 5 mM azide, 50 µM phloretin and 500 µM pCMBS. The straight lines represent initial slopes of lactate accumulation fitted by linear regression within the same range of ratio values. (C) Summary of the initial slopes (Δ ratio/min) obtained in three experiments of the type shown in A and B. (D) Correlation plot between the rates of lactate accumulation (Δ ratio/min) in azide and in pCMBS. Symbols represent single astrocytes (white), HEK293 cells (gray) or T98G cells (black). (E) The Warburg Index was estimated as the ratio between the rates of lactate production with pCMBS and lactate accumulation with azide, and used to color the silhouette of each cell according to the 16-color look up table. The inset shows an isolated cell that was located about 100 µm from the cluster. The bar graph summarizes data from 3 experiments in each cell type. Scale bars are 20 µm. *, p < 0.05 between every cell type.