Resveratrol ameliorates Lewis lung carcinoma-bearing mice development, decreases granulocytic myeloid-derived suppressor cell accumulation and impairs its suppressive ability

Myeloid-derived suppressor cells (MDSC) are a heterogeneous population of immature myeloid cells which consist of 2 subsets: granulocytic MDSC (G-MDSC) and monocytic MDSC (M-MDSC). MDSC expand in tumor-bearing hosts and contribute to immunotherapeutic resistance by remarkably blocking effector T-cell activation via different mechanisms. Resveratrol (RSV) is a polyphenol and it has been widely used for its various health benefits. However, the underlying mechanism of its anti-tumor properties remains unclear. In this study, a transplantable mouse model was used to investigate the effects of RSV on MDSC. The results showed that RSV ameliorated tumor development by decreasing G-MDSC accumulation, impairing its suppressive ability on CD8⁺ T cells and promoting M-MDSC differentiation into CD11c⁺ and F4/80⁺ cells. Our results indicated that RSV should be considered as a modular of MDSC suppressive function and that RSV is a novel booster for tumor immunotherapy.