Testosterone-TGF-β crosstalk modulates cell migration in human glioblastoma-derived cell lines.

Glioblastoma (GB) is the most aggressive brain tumor due to its extensive cellular migration. Although testosterone (T) and transforming growth factor-β (TGF-β) can regulate GB cell migration, the interaction between them in migration regulation in GB cells remains unclear. Here, we evaluated whether testosterone modulates TGF-β signaling to regulate cell migration in two human GB-derived cell lines. Androgen response elements (AREs) within the TGF-β gene were identified in-silico. The effects of T on TGF-β signaling were evaluated in U251 and T98G human GB-derived cell lines. TGF-β secretion was quantified by ELISA, and TGF-β/SMAD signaling activation after T stimulation was assessed by Western blot. Cell migration was analyzed by the scratch assay in the presence of SB431542, a TGF-β pathway inhibitor. Seven AREs were identified in the TGF-β gene. T increased TGF-β secretion in U251 but not in T98G cells. Consistently, T-induced SMAD activation was only observed in U251 cells. Inhibition of TGF-β signaling with SB431542 reduced T-stimulated migration exclusively in U251 cells. Our data demonstrate, for the first time, that T activates TGF-β signaling, promoting cell migration in U251 but not in T98G cells, highlighting cell line-specific heterogeneity in GB responses to the same hormonal stimulus.