TIGAR maintains mitotic spindle organization and βII-tubulin stability in glioma stem cells, correlating with poor GBM prognosis

Glioblastoma (GBM) is an aggressive brain malignancy driven by glioma stem cells (GSCs), which contribute to its high recurrence and poor prognosis. TIGAR (TP53-induced glycolysis and apoptosis regulator) is primarily known for its metabolic role in cell survival, but its non-metabolic functions, particularly in neuro-oncology, remain largely unexplored. Understanding TIGAR's structural role in maintaining mitotic spindle integrity and its interplay with the ubiquitin-proteasome system in GSCs could reveal new therapeutic vulnerabilities for GBM.

Researchers investigated TIGAR's role in GSCs using human GSC lines (GSC464 and GSC23) where TIGAR expression was ablated via lentiviral shRNA knockdown. Cell cycle progression and spindle morphology were analyzed using flow cytometry and immunofluorescence. Protein interactions and stability were assessed through immunoprecipitation, cycloheximide chase, ubiquitination assays, NAC rescue testing, and Parkin co-depletion rescue assays. In vivo effects of TIGAR depletion were evaluated using GSC-derived orthotopic xenografts in SCID mice and an HRas-driven, p53-deficient primary glioblastoma mouse model.

TIGAR expression was significantly upregulated in human GBM, correlating with tumor malignancy, stemness features, and poor patient prognosis across GEPIA2, TCGA, CGGA, GTEx, and PDX-based analyses. Public transcriptomic data showed a positive association between TIGAR expression and a GSC-related stemness signature, with double immunofluorescence confirming TIGAR co-localization with SOX2 or CD133 in two PDX models. TIGAR ablation in GSCs induced G2/M arrest and severe spindle defects, effects validated in an additional GSC line. Mechanistically, TIGAR localizes to the mitotic spindle and physically interacts with βII-tubulin.