Fig. 3

Lipid metabolism of immune cells and the immunosuppressive cells in tumor microenvironment. Scheme showing lipid and energy metabolism of immune cells and the immunosuppressive cells in tumor microenvironment. The tumor suppressive immune cells with warm-toned in cytosol are shown in left, while the tumor-promoting cells with cold-toned in cytosol are shown in right. Increased fatty acid synthesis in dendritic cells and increased fatty acid oxidation in CD4⁺ T cells are found in tumor microenvironment. The responder CD8⁺ T cells (cytotoxic T cells) produce ATP via glycolysis for energy supply, however, tumor cell can rewrite the lipid metabolic programs of TILs which decrease glycolysis but increase FAO for energy supply. Tumor cell can also concerting MDSCs and TAMs to immunosuppressive cells. Treg cells can trigger senescence of cytotoxic T cells. Increased FAO is also found in the immunosuppressive cells (MDSC, Treg, and TAM) as well as in M2-macrophage