Reprogramming Tumor Associated Macrophage Phenotype by a Polysaccharide from Ilex asprella for Sarcoma Immunotherapy.

We report here the discovery of an acidic polysaccharide, namely IAPS-2, from the root of Ilex asprella, with anti-tumor activity via a repolarizing tumor associated macrophages (TAMs) phenotype. We obtained IAPS-2 polysaccharide from this herb based on acidity and found that IAPS-2 expressed the activity of promoting the secretion of anti-tumor cytokines in macrophages. Furthermore, we evaluated its anti-tumor effect on TAM cells, through the activation of nuclear factor-κB (NF-κB) and signal transducer and activator of transcription (STAT) signaling. In particular, in the tumor murine model, IAPS-2 demonstrated that it could significantly inhibit the growth of tumors via modulating the function of TAMs and increase the animal survival rate. In summary, IAPS-2, with a clearly illustrated chemical composition, potent anti-tumor activity, and a solid mechanism of action, may be developed into a valuable therapeutic tool for cancer immunotherapy.