Fatty Acid Metabolism and Hypoxia in the Tumor Microenvironment: Metabolic Adaptation and Clinical Potential in Colorectal Cancer.

Colorectal cancer (CRC) is a major cause of cancer morbidity and mortality worldwide, and metabolic reprogramming is increasingly recognized as an important feature of its progression. Among these changes, fatty acid metabolism (FAM) has drawn growing attention because it supports energy supply, membrane synthesis, redox balance, and stress adaptation in tumor cells. CRC cells can increase fatty acid uptake, activate de novo synthesis, adjust fatty acid oxidation (FAO), and alter lipid droplet (LD) dynamics according to metabolic demand. These processes are strongly influenced by the hypoxic tumor microenvironment. Under hypoxic conditions, signaling pathways centered on hypoxia-inducible factors (HIFs) reshape lipid uptake, synthesis, oxidation, and storage, allowing CRC cells to maintain survival and adapt to limited oxygen and nutrient availability. Increasing evidence suggests that this metabolic shift is closely linked to invasion, metastasis, stem-like behavior, and resistance to therapy. In this review, we provide an integrated overview of the hypoxia-FAM axis in CRC. We first summarize the major steps of FAM reprogramming, then highlight how hypoxia reshapes these processes through HIF-dependent and related pathways. We also discuss FAM crosstalk with stromal and immune cells, experimental models, and metabolic heterogeneity between primary CRC and liver metastases. Finally, we discuss therapeutic strategies targeting FAM and hypoxia-associated signaling in CRC.