A. Red boxes denote metastatic locations of interest on both the left (L) and right (R) sides of the mouse being the foot (F), knee (K), and ovary (O). B. Representative bioluminescence images of mice four weeks post femoral artery injection. Pseudocolor scale depicts range of values with red being highest and blue lowest values, respectively. C. Metastatic incidence of MCF7 cells in mice 4 weeks post-injection. N = 19. D. Representative images of MCF7 cells marked by red nuclei (top) and corresponding pseudocolor map of NADH lifetimes (bottom) in bone marrow of a mouse. Longer NADH lifetimes (red) represent increased usage of NADH for OXPHOS over glycolysis. Scale bar = 30 μm. E. Histogram displays NADH lifetimes for MCF7 breast cancer cells in bone marrow of mice. N = 35 images from 3 mice, F. Representative images of MCF7 cells (red nuclei) expressing ERK and Akt KTRs in bone marrow of mice. Regions of interest define cancer cell nuclei. Scale bar = 15 μm, G Quantification of ERK and Akt KTR activation displayed as the log base 2 of the cytoplasmic to nuclear ratios of fluorescence intensities (CNR) for each channel in single cells. **** = p < 0.0001. N = 393 cells over 3 mice