Monocyte - neutrophil interplay drives mesenchymal transition in GBM. Monocyte - neutrophil interplay drives mesenchymal transition in GBM

Myeloid cells comprise the majority of immune cells in tumors, where their content and composition is not only driver mutation-specific, but also tumor type-dependent. While these cells are essential for shaping the tumor microenvironment, promoting tumor growth, and contributing to therapeutic resistance, targeting tumor-associated myeloid cells, including bone-marrow-derived monocytes and neutrophils, has not been successful. To eliminate monocyte recruitment, we employed CRISPR/Cas9-based methods to delete the region on murine chromosome 11 harboring the monocyte chemoattractant protein family (MCP) genes, Ccl2, Ccl7, Ccl8, Ccl12, and Ccl11, which we termed qMCP-KO. Using these qMCP-knockout mice in combination with genetically engineered mouse models (GEMM) of glioblastoma (GBM), we investigated myeloid infiltraion by sc-RNA seq. We found that when monocyte infiltraion was abolisehd, a compensatory influx of nuetrophil in these tumor occured. These neutrophil promote tumor growth by releasing TNF, contributing to tumor hypoxic responses and aggression. Overall design: We induced de novo brain tumor in WT, qMCP-KO mice of both genders. We isolated brain tumor cells at the humane endstage of these mice and ran sc-RNA seq on these cells to compare their functional differences.