Hypoxia-responsive gene F3 Promotes GBM Cell Proliferation and Migration through Activating NF-κB/p65 Signaling Pathway.

ABSTRACT

Background: Glioblastoma multiforme (GBM) is the most common malignant form of glioma, but the molecular mechanisms underlying the progression of GBM in hypoxic microenvironment remain elusive. This study aims to explore the pathological functions of hypoxia-responsive genes on GBM progression and its downstream signaling pathways. Methods: RNA-seq was performed in normoxic and hypoxic U87 cells to identify the differentially expressed genes (DEGs) under hypoxia. The mRNA expression levels of hypoxia-responsive gene F3 in glioma clinical samples were analyzed according to the transcriptional information from CGGA, TCGA and Rembrandt databases. EdU, transwell and wound-healing assays were conducted to evaluate the pathological functions of F3 on GBM proliferation and migration under hypoxia. RNA-seq and gene set enrichment analysis were conducted to analyze the enriched pathways in LN229 cells overexpressed F3 compared to controls. GBM cells were treated with NF-κB inhibitor PDTC, and cell experiments were performed to evaluate the effects of PDTC on OE-F3-LN229 and OE-F3-U87 cells. Western blot was performed to validate the downstream pathways. Results: F3 was identified as a hypoxia responsive gene in GBM cells. The mRNA expression level of F3 was negatively correlated with the overall survival of glioma patients, and significantly increased in grade IV and GBM than lower grade or other histology of glioma. Overexpression of F3 enhanced the proliferation and migration of hypoxic U87 and LN229 cells, while knockdown inhibited them. In OE-F3-LN229 cells, the NF-κB pathway was activated, with an increased level of phosphorylated p65. PDTC treatment effectively rescued the enhanced proliferation and migration of OE-F3-LN229 cells under hypoxia, indicating that the effect of F3 on GBM progression is probably dependent on the NF-κB pathway. Conclusion: Hypoxia-induced F3 activates NF-κB pathway through upregulation of the phosphorylated p65, thus promoting the proliferation and migration of GBM cells under hypoxia, which might be a potential therapeutic target for GBM treatment.