The immunosuppressive microenvironment modulated by glioma-associated mesenchymal stem cells: Current status and potential strategies.

Abstract

Glioma, the most prevalent primary malignant tumor of the central nervous system, exhibits aggressive progression and poor prognosis, largely due to its highly immunosuppressive tumor microenvironment (TME). Glioma-associated mesenchymal stem cells (GA-MSCs), a key component of the glioma TME, play a dual and context-dependent role in tumor biology. On one hand, GA-MSCs actively shape immunosuppression by interacting with various immune cells-including T cells, B cells, natural killer (NK) cells, dendritic cells (DCs), and macrophages-via soluble factors (e.g., TGF-β, PGE2, miR-21) and cell-contact mechanisms, thereby facilitating tumor immune evasion. They also promote glioma progression by enhancing the stemness, invasiveness, and chemoresistance of glioma stem cells (GSCs) through pathways such as IL-6/STAT3 and mitochondrial transfer, while contributing to pathological angiogenesis via differentiation into pericytes and secretion of pro-angiogenic factors like VEGF. On the other hand, GA-MSCs possess therapeutic potential: genetically engineered GA-MSCs can secrete pro-inflammatory cytokines (e.g., IL-12, IFN-β) or immune checkpoint blockers (e.g., scFv-PD1) to reverse immunosuppression, serve as carriers for targeted delivery of chemotherapeutics, miRNAs, suicide genes, or oncolytic viruses, and enhance anti-tumor immune responses. However, clinical translation is hindered by challenges including residual immunosuppressive activity, unstable transgene expression, limited migration efficiency, and safety concerns. This review summarizes the complex mechanisms by which GA-MSCs modulate the glioma TME, highlights their bidirectional roles in tumor progression and immunotherapy, and discusses potential strategies to overcome current limitations, aiming to provide insights for developing novel therapies targeting GA-MSCs and their interactions within the glioma microenvironment.