Fig. 2

CAAs in the tumor-associated adipose microenvironment. The tumor microenvironment is composed of various types of cells, including cancer cells, stromal and immune cells. CAAs are one of the most important components that play an important role in the progression and development of cancer via metabolic reprogramming and cytokines interacting with tumor cells and immune cells, such as macrophages, T cells, NK cells and dendritic cells. CAAs inhibit the differentiation and proliferation of Teff cells and NK T cells, while play a positive effect on that of Tregs and TANs. CAAs also facilitate the alternatively polarization of macrophages to a M2-like phenotype, promoting the invasion and migration. Overall, CAAs interacts with stromal cells and immune cells to facilitate tumor progression. ARG1:arginase 1; ATP: adenosine triphosphate; CD36: cluster of differentiation 36; CPT-1α: carnitine palmitoyl transferase 1α; DC: dendritic cells; FABP: fatty acid-binding protein; FAO: fatty acid oxidation; FATP1: fatty acid transport protein 1; FFA: free fatty acid; GPR132: G protein-coupled receptor 132; GPR8: G protein-coupled receptor 8; HIF1: hypoxia inducible factor-1; IL-10: interleukin-10; IL-12: interleukin-12; MCT1: monocarboxylate transporter 1; MCT4: monocarboxylate transporter 4; mTORC1: mammalian target of rapamycin complex 1; NK cell: natural killer cell; NOS2: nitric oxide synthase 2; OXPHOS: oxidative phosphorylation; PD1: programmed cell death protein 1; PD-L1: programmed cell death 1 ligand 1; PGC-1β: peroxisome proliferator-activated receptor-γ coactivator 1β; PKA: protein kinase A; PPARγ: peroxisome proliferators-activated receptor γ; TAM: tumor-associated macrophage; TAN: tumor-associated neutrophil; Tregs: T regulatory cells; VEGF: vascular endothelial growth factor