Succinate in the tumor microenvironment affects tumor growth and modulates tumor associated macrophages

Succinate is an important metabolite that modulates metabolism of immune cells and cancer cells in the tumor microenvironment (TME). Herein, we report that polyethylene succinate (PES) microparticles (MPs) biomaterial mediated controlled delivery of succinate in the TME modulates macrophage responses. Administering PES MPs locally with or without a BRAF inhibitor systemically in an immune-defective aging mice with clinically relevant BRAF^V600E mutated YUMM1.1 melanoma decreased tumor volume three-fold. PES MPs in the TME also led to maintenance of M1 macrophages with up-regulation of TSLP and type 1 interferon pathway. Impressively, this led to generation of pro-inflammatory adaptive immune responses in the form of increased T helper type 1 and T helper type 17 cells in the TME. Overall, our findings from this challenging tumor model suggest that immunometabolism-modifying PES MP strategies provide an approach for developing robust cancer immunotherapies.