The Interdependence of Carbon Substrates and Metabolic Pathways Enables the Metabolic Plasticity of Cancer Cells

The tumor microenvironment (TME) functions as a dynamic and co-evolving ecosystem, where malignant and non-malignant cells form a metabolically interdependent community. This ecological view reimagines tumors not as isolated cell masses, but as complex biotopes in which cellular interactions are integral to tumor initiation, growth, and progression. A hallmark of this adaptive environment is metabolic plasticity-an essential mechanism that enables tumor cells, including the metastatic ones, to reprogram their metabolism in response to fluctuating nutrient availability and environmental stressors. At the core of this reprogramming lies carbon metabolism, characterized by the selective and flexible utilization of key metabolites, including glucose, lactate, glutamine, cysteine, and fatty acids. These compounds support energy production, biomass synthesis, and redox balance, while also facilitating the export and repurposing of metabolic byproducts for signaling or reuse. This chapter presents a conceptual framework that explores the interdependence of central metabolic pathways, emphasizing how tumors coordinate energy generation, biosynthesis, and redox control to support malignant progression.