TGF-β-induced ganglioside remodeling highlights GD2 as a dynamically regulated target in glioblastoma

Glioblastoma (GBM) is characterized by extensive cellular plasticity and dynamic interactions with the tumor microenvironment. The tumor-associated ganglioside GD2 is considered a promising therapeutic target, although its stability across different cellular states remains unclear. Here, we investigated whether transforming growth factor-β (TGF-β), a key regulator of glioblastoma progression and mesenchymal reprogramming, modulates ganglioside-biosynthetic gene expression and GD2 surface expression. Using U87-MG and U251-MG glioblastoma cell lines, we combined MALDI–TOF-MS glycosphingolipid profiling, flow cytometry, quantitative PCR, Western blot analysis, and migration assays to characterize TGF-β–induced phenotypic changes. Baseline analyses revealed marked differences in ganglioside composition between the two cell lines. TGF-β induced distinct mesenchymal-like phenotypic responses and differentially regulated ganglioside-biosynthetic gene expression, resulting in opposite effects on GD2 surface expression: GD2 levels increased in U251-MG cells but decreased in U87-MG cells. These changes were accompanied by cell line–specific alterations in migratory behavior. Pharmacological inhibition of UDP-glucose ceramide glucosyltransferase (UGCG) reduced GD2 expression and attenuated migration, supporting a broader contribution of glycosphingolipid biosynthesis to migratory behavior. Together, these findings demonstrate that GD2 expression is dynamically regulated by microenvironmental signaling and is associated with TGF-β-induced phenotypic changes in the glioblastoma cell models examined. Our results identify changes in ganglioside-biosynthetic gene expression and GD2 surface abundance as molecular features accompanying tumor cell plasticity and suggest that GD2 should be considered a context-dependent therapeutic target rather than a stable tumor-associated marker.