Testosterone increases clonogenicity and self-renewal capacity of human glioblastoma cells

Glioblastoma is the most common and aggressive malignant brain tumor in adults, characterized by rapid progression and limited therapeutic response. The presence of glioma stem cells contributes to high recurrence and treatment resistance. Epidemiological data indicate a higher incidence of glioblastoma in men than in women, suggesting a potential role for sex hormones in disease progression. To evaluate the influence of testosterone on glioblastoma stemness-associated characteristics, male human glioblastoma-derived cell lines were analyzed for androgen receptor (AR) regulation and responses to testosterone exposure. AR protein levels were quantified, and functional assays were performed to assess clonogenicity, neurospheres formation, and stemness-associated gene expression. T98G and U251 human glioblastoma cell lines expressed AR. Notably, neurospheres exhibited a higher AR expression than cells in monolayer cultures, and testosterone further increased its expression. In suspension cultures, testosterone significantly enhanced clonogenic potential, as evidenced by increased numbers and sizes of primary and secondary neurospheres. Testosterone upregulated the expression of stemness-associated genes (PROM1, SOX2, and NES) and, in differentiation assays, elevated the number of Sox2-positive cells. Overall, these findings suggest that testosterone increases clonogenicity and self-renewal capacity of human glioblastoma cells, highlighting androgen signaling as a critical regulator of tumor resilience and a promising therapeutic target to disrupt the maintenance of glioblastoma stem-like cells.