Abstract

Glioblastoma multiforme (GBM), isocitrate dehydrogenase (IDH)-wildtype, is the most aggressive primary malignant tumor of the central nervous system, characterized by poor prognosis and high recurrence rates despite standard multimodal treatment. This study investigates the molecular response of glioblastoma cells to 5-aminolevulinic acid (5-ALA)-based photodynamic therapy (PDT), focusing on gene expression changes associated with apoptosis, ferroptosis, and oxidative stress. Human glioblastoma T98G cells were treated with 5-ALA followed by light irradiation, and gene expression was analyzed using RT-qPCR. PDT induced moderate upregulation of pro-apoptotic genes (BAX, CASP3, FAS) alongside increased expression of the anti-apoptotic gene BCL2, indicating simultaneous activation of cell death and survival pathways. Ferroptosis-related genes showed mixed responses, with slight upregulation of ACSL4 and downregulation of GPX4, suggesting increased susceptibility to lipid peroxidation. The most significant change was observed in GCH1 expression, reflecting activation of oxidative stress response mechanisms. However, none of the observed changes reached statistical significance, likely due to the limited sample size. These findings demonstrate that PDT induces a complex and dual biological response in glioblastoma cells, involving both cytotoxic and adaptive mechanisms. This may limit therapeutic efficacy and contribute to treatment resistance. The results support the rationale for combining PDT with targeted molecular therapies aimed at inhibiting antioxidant defenses and anti-apoptotic pathways. Additionally, personalized therapeutic strategies based on tumor molecular profiles may enhance treatment outcomes. Further studies with larger sample sizes and functional validation are required to confirm these preliminary observations.

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