Figure 9.

Metabolic compartments in parasitic cancer metabolism. In summary, we believe that cancer cells act as metabolic parasites and extract nutrients from host cells by inducing catabolic processes (autophagy, mitophagy, aerobic glycolysis and lipolysis). As a consequence, the tumor stroma shows a shift toward aerobic glycolysis, and epithelial cancer cells show functional hyper-activation of oxidative mitochondrial metabolism (OXPHOS). In support of this model, cancer-associated fibroblasts and the tumor stroma overexpress PKM2 (a rate-limiting glycolytic enzyme, left panel). Conversely, breast cancer epithelial cells upregulate MT-CO1 (a key component of mitochondrial complex IV, right panel). The metabolic compartmentalization of PKM2 and MT-CO1 were visualized by immunostaining with specific antibody probes (brown reaction product). Reproduced and modified with permission from references 14 and 80.