P02.06.B CROSSTALK BETWEEN GLIOMA AND MYELOID SHAPES DISTINCT TUMOR MICROENVIRONMENT IN SPINAL CORD, BRAIN STEM AND CEREBRUM

Abstract BACKGROUND Occurring in the cerebrum, brainstem, and spinal cord, glioma are the most common primary malignant tumors in the central nervous system. Currently, there is a increasing understanding of the microenvironment of cerebral gliomas and brainstem gliomas, and clinical trials of immunotherapy for them are also ongoing. However, research on the microenvironment of spinal cord glioma is still lacking, Their immunotherapy potential deserve further exploration. MATERIAL AND METHODS We performed single-cell sequencing of fresh tissues from 8 cases of spinal cord DMG. Through integrating public scRNA data from 19 brain glioblastoma cases and 9 cases of DIPG samples, we did an integrated analysis of 199,696 human glioma, immune, and other stromal cells at the single cell level. Further analysis of cell communication revealed the distinct interaction between glioma cells and different cells in the microenvironment, especially tumor infiltrating macrophages. RESULTS Single cell analysis indicates that the main participants in the glioma microenvironment are tumor cells and tumor infiltrating macrophages; In addition, compared to midline gliomas, brain gliomas contain a higher proportion of lymphocytes. Interaction analysis revealed that spinal cord gliomas can regulate the infiltration of macrophages in spinal cord gliomas through the THY1-ADGR5 axis and higher expression of IGF1 by macrophages, promoting the proliferation and invasion of gliomas with IGF1R. CONCLUSION This study provides insights into molecular, spatial, and functional heterogeneity of glioma and glioma-associated immune cells in GBM, DIPG and spinal cord DMG, suggesting that selectively modulating tumor-related immunosuppressive regulatory networks might reprogram the microenvironment and provide an immunotherapeutic strategy for treating glioma.