The Current Application and Future Prospects of Astragalus Polysaccharide Combined With Cancer Immunotherapy: A Review

So far, immunotherapy has been shown to have impressive effects on different cancers in clinical trials. All those immunotherapies are generally derived from three main therapeutic approaches: immune checkpoint inhibitors, immune cell vaccination, and adoptive cellular immunotherapy. Our research systematically reviewed a wide range of clinical trials and laboratory studies of astragalus polysaccharide (APS) and elucidated the potential feasibility of using APS in activating adoptive immunotherapy. Apart from being effective in adaptive “passive” immunotherapy such as lymphokine-activated killer treatment and dendritic cell (DC)–cytokine–induced killer treatment, APS could also regulate the anti-programmed cell death protein 1 (PD-1)/PD-L1 on the surface of the immune cells, as a part in the immune checkpoint inhibitory signaling pathway by activating the immune-suppressed microenvironment by regulating cytokines, toll-like receptor 4 (TLR4), nuclear factor kappa B (NF-κB), and mitogen-activated protein kinase (MAPK) pathways, and immune cells, such as DCs, macrophages, NK cells, and so on. In view of the multiple functions of APS in immunotherapy and tumor microenvironment, a combination of APS and immunotherapy in cancer treatment has a promising prospect.