P4HB regulates tumor-associated macrophage polarization and chemotaxis by enhancing IL-6 cytokine secretion in glioblastoma.

BACKGROUND: Prolyl 4-hydroxylase subunit beta (P4HB) has been linked to glioma progression and treatment resistance; however, its role in the tumor microenvironment regulation remains unclear. MATERIALS AND METHODS: A total of 90 human glioma samples and 30 normal traumatic brain injury (TBI) tissues from patients undergoing surgical resection were collected from the First Affiliated Hospital of Zhengzhou University for immunohistochemical (IHC) staining. The signaling pathway mechanism regulating prognosis and tumor proliferation was explored through bioinformatics analysis and functional assays via P4HB knockdown. RESULTS: The IHC analysis of 90 glioma and 30 TBI tissues revealed that P4HB expression correlated with tumor malignancy, especially the WHO grade 4 and grade 2 (P < 0.0001). Furthermore, transcriptomic data analysis identified P4HB as a prognostic marker associated with poor survival and tumor-associated macrophage infiltration (P < 0.05 in all cohorts). Using shRNA lentiviral constructs, stable P4HB knockdown glioblastoma (GBM) cell lines were generated. mRNA sequencing revealed significant downregulation of the interleukin (IL)-6/signal transducer and activator of transcription 3 (IL-6/STAT3) signaling axis. Functional studies showed that P4HB deficiency resulted in reduced IL-6 secretion (P < 0.0001), suppressed M2 polarization of tumor-associated microglia, and inhibited glioma cell growth both in vitro and in vivo, with IL-6 neutralization recapitulating these effects. Mechanistically, P4HB promoted STAT3 phosphorylation in microglia, driving their pro-tumorigenic M2 phenotype. CONCLUSION: These findings establish P4HB as a regulator of glioma progression via IL-6/STAT3-mediated microglial polarization, highlighting its potential as a therapeutic target for GBM.