Abstract
Intrinsic immunosuppressive tumor microenvironment (ITM) and insufficient tumor infiltration of T cells severely impede the progress of glioblastoma (GBM) immunotherapy. In this study, it is identify that inhibiting the expression of glucose transporter 1 (GLUT1) can facilitate the prevention of lactate excretion from tumor glycolysis, which significantly alleviates the lactate-driven ITM by reducing immunosuppressive tumor-associated macrophages (TAMs) and regulatory T cells (Tregs). Simultaneously, the findings show that the generated inflammatory cytokine IFN-γ during immune activation aggravates the immune escape by upregulating immune checkpoint programmed death-ligand 1 (PD-L1) in tumor cells and TAMs. Therefore, an injectable thermogel loaded with a GLUT1 inhibitor BAY-876 and a PD-1/PD-L1 blocker BMS-1 (Gel@B-B) for dual-regulation of metabolism and immunity of GBM is developed. Consequently, in situ injection of Gel@B-B significantly delays tumor growth and prolongs the survival of the orthotopic GBM mouse model. By actively exposing tumor antigens to antigen-presenting cells, the GBM vaccine combined with Gel@B-B is found to significantly increase the fraction of effector T cells (Th1/CTLs) in the tumor microenvironment, thereby remarkably mitigating tumor recurrence long-term. This study may provide a promising strategy for GBM immunotherapy.