Abstract
Background
The Warburg effect drives glioblastoma (GBM) progression, but its upstream regulators remain unclear. This study investigated the role and mechanism of nucleoporin 35 (NUP35) in GBM glycolytic reprogramming.Methods
Public datasets, including The Cancer Genome Atlas (TCGA) and the Genotype-Tissue Expression (GTEx) database, were analyzed to identify glycolysis-related genes in GBM. Functional enrichment and protein-protein interaction analyses were performed. NUP35 gain- and loss-of-function models were used to assess glycolysis, HK2 activity, lactate production, apoptosis, invasion, and tumor growth. Co-immunoprecipitation, ubiquitination, protein stability, and molecular docking assays were used to explore the mechanism.Results
Bioinformatics analyses identified NUP35 as a key glycolysis-associated molecule that was markedly upregulated in GBM tissues and significantly associated with poor clinical outcomes. Functional enrichment analyses demonstrated that NUP35-related genes were predominantly enriched in glycolytic metabolism, energy metabolism, and tumor progression-associated signaling pathways. Functional experiments further showed that NUP35 enhanced glycolytic reprogramming by increasing HK2 activity and lactate production, thereby promoting GBM cell invasion, suppressing apoptosis, and accelerating tumor growth in vivo. Mechanistically, NUP35 regulated GCKR protein abundance without altering GCKR transcription. TRIM25 interacted with GCKR, and TRIM25 knockdown or expression of the GCKR-K525A mutant reduced GCKR ubiquitination and restored total GCKR protein levels in NUP35-overexpressing cells. These findings support a requirement for TRIM25 and the K525 residue of GCKR in GCKR ubiquitination and degradation under NUP35-overexpressing conditions, with consequent changes in HK2 activity and glycolytic metabolism.Conclusions
NUP35 promotes glycolytic reprogramming and malignant progression in GBM by regulating GCKR protein stability and HK2 activity. TRIM25 is required for GCKR ubiquitination and degradation under NUP35-overexpressing conditions, supporting a proposed NUP35-TRIM25-GCKR-HK2 regulatory model.