Fig 6. Optical spectroscopy reveals differences in glycolytic and vascular characteristics of 4T1 murine mammary tumors.

A. SO₂ is significantly lower in 4T1 (both normoxia and hypoxia) tumors compared with normal tissue. B. 2-NBDG₆₀ is significantly higher in 4T1 tumors exposed to normoxia and hypoxia compared with normal tissue (p = 0.02 and 0.03, respectively). C. Blockade of respiration with oligomycin significantly reduces OCR in the 4T1 cells. D. However, there is only a small but insignificant increase in ECAR in response to oligomycin. Data represent n = 12 cell samples from 3 distinct assays. E. 2-NBDG₆₀ is inversely correlated with SO₂ for the 4T1 tumors that were exposed to 21% O₂ and 10% O₂ (r = -0.73; p = 0.01). Non-tumor-bearing mice, and 4T1 tumor-bearing mice that were breathing normoxia and hypoxia are shown here. 4T1 tumor-bearing mice were exposed to 10% oxygen (rest nitrogen) prior to 2-NBDG injection. F. 2-NBDG uptake in the 4T1 tumors is positively correlated with tumor volume (r = 0.79; p = 0.07). Error bars indicate standard error of the mean.