Restoring the glioblastoma tumor microenvironment by targeting C5a with the antagonist W54011

Glioblastoma (GBM) poses a serious challenge due to its aggressive nature and poor prognosis. Tumor mesenchymal stem-like cells (tMSLCs) secrete complement component 5a (C5a), altering the tumor microenvironment (TME) and promoting tumor progression. This study investigated W54011, a C5a antagonist, to counteract C5a-induced malignancy in GBM tumorspheres. We assessed GBM tissues for C5a receptor 1 (C5aR1) expression using gene profiling and survival analysis. GBM tumorspheres were cultured in C5a-enriched conditioned medium (CM) from tMSLCs to induce tumor stimulation. We evaluated proliferation, invasion, and stemness of GBM tumorspheres using WST/ATP, matrigel invasion assay, and limiting dilution assays. Results were validated via western blotting and RNA sequencing. Additionally, findings were corroborated in an in vivo xenograft mouse model. High C5aR1 expression correlated with increased TME, inflammation-related gene expression, and poorer patient outcomes. CM treatment increased GBM tumorsphere proliferation, invasion, and stemness, which were reversed by W54011. CM also induced the epithelial-mesenchymal transition, whereas W54011 restored spherical morphology and induced apoptosis. In xenograft models, CM-treated GBM tumorspheres led to larger tumors and decreased survival, whereas W54011 decreased tumor size and improved survival. This study suggests a potential role for C5a in GBM progression and supports further investigation of W54011 as a therapeutic candidate.