The role of metabolic reprogramming of tumor-associated macrophages in shaping the immunosuppressive tumor microenvironment

Macrophages are potent immune effector cells in innate immunity and exert dual-effects in the tumor micro -environment (TME). Tumor-associated macrophages (TAMs) make up a significant portion of TME immune cells. Similar to M1/M2 macrophages, TAMs are also highly plastic, and their functions are regulated by cytokines, chemokines and other factors in the TME. The metabolic changes in TAMs are significantly associated with polarization towards a protumour or antitumour phenotype. The metabolites generated via TAM metabolic reprogramming in turn promote tumor progression and immune tolerance. In this review, we explore the metabolic reprogramming of TAMs in terms of energy, amino acid and fatty acid metabolism and the potential roles of these changes in immune suppression.

Automated summary

Macrophages in the tumor micro-environment (TME) play a significant role in innate immunity and have dual effects. Tumor-associated macrophages (TAMs) are a major component of immune cells in the TME. TAMs, like M1/M2 macrophages, are highly adaptable and their functions are influenced by cytokines, chemokines, and other TME factors. Metabolic changes in TAMs are closely associated with their polarization towards promoting or suppressing tumor growth. The metabolic reprogramming of TAMs generates metabolites that contribute to tumor progression and immune evasion. This review examines the metabolic reprogramming of TAMs in terms of energy, amino acid, and fatty acid metabolism, and explores their potential roles in immune suppression.