Single-cell sequencing analysis reveals the ‍promotion of ELR CXCL genes on angiogenesis and the influence on malignant progression in glioblastoma

Abstract

Glioblastoma (GBM) is a highly aggressive cancer that significantly impacts human health. Myeloid cells and bone marrow-derived macrophages (BMDMs) are major components of tumor micro­environ­ment; however, their roles in GBM tumorigenesis, progres­sion, and treatment response remain unclear due to considerable heterogeneity. Single-cell sequencing data for GBM were collected from the Gene Expression Omnibus (GEO) database to analyze the heterogeneity of GBM cell subpopulations. Trends in myeloid cell subpopulations were examined, identifying cancer-associated BMDMs and key genes that were specifically over­expressed in this subgroup. Validation was performed through experiments in vitro, including quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) to measure mRNA expres­sions of chemokine (C-X-C motif) ligand 3 (CXCL3), vascular endothelial growth factor A (VEGF-A), and matrix metallo­peptidase 9 (MMP9); angiogenesis assays to observe endothelial cell tube formation; Cell Counting Kit-8 (CCK-8) assays to assess cell viability; colony formation assays for cell proliferation; Transwell assays to evaluate cell migration and invasion; and flow cytometry to measure apoptosis. Eight distinct cell types were identified in GBM, with a notable proportion of myeloid cells. Cancer-related BMDMs were characterized within the myeloid cell population, revealing specific overexpression of Glu-Leu-Arg (ELR) CXCL genes associated with angiogenesis and tumor develop­ment. Experiments in vitro confirmed that the ELR CXCL-related gene CXCL3 derived from BMDMs promoted angiogenesis and influenced GBM malignancy. The ELR CXCL + BMDM subgroup represented a critical cell type associated with the rapid growth of GBM, as the secreted CXCL3 enhanced angiogenesis and impacted GBM malignant progression.