EXTH-41. A bench-top model for the sonodynamic therapy of medulloblastoma

Abstract Medulloblastoma (MB), the most common malignant pediatric brain tumor, poses significant therapeutic challenges; current treatments often induce severe long-term morbidities. Sonodynamic therapy (SDT), a non-invasive modality using ultrasound to activate a sonosensitizer for targeted reactive oxygen species (ROS) generation, offers a promising alternative. However, in-vitro SDT models lack standardization and reproducible experimental setups. This study aimed to develop a bench-top model evaluating 5-aminolevulinic acid (5-ALA)-mediated SDT efficacy in the UW426 cell line, assessing ROS production, cell death, and proliferation. UW426 cells (SHH-activated, TP53-mutant) were incubated with 5-ALA (200µg/mL, 24h) to maximize protoporphyrin IX (PpIX) fluorescence. A 1.5MHz focused ultrasound (FUS) transducer (0.91MHz operating) targeted the base of 96-well plates; pressure wave delivery was confirmed by needle hydrophone. Groups included: untreated control, 5-ALA alone, FUS alone, and SDT (5-ALA + FUS). FUS/SDT utilized varied acoustic powers (1W, 3W, 6W) and durations (60s, 90s, 120s). 24h following treatment, intracellular ROS, apoptotic markers, and proliferation were quantified. SDT induced a statistically significant elevation in intracellular ROS levels in UW426 cells versus all controls (p<0.05). This correlated with significantly reduced cell viability and increased apoptotic cell death in the SDT group (p<0.05), demonstrating potent synergistic cytotoxicity. Proliferation was also significantly reduced in the SDT treatment group. Utilizing 6W power and 120s treatment duration yielded the most significant induction of ROS, cell death and decreased proliferation. In this study we demonstrated a reliable bench-top SDT model. The efficacy’s dependence on ultrasound parameters underscores the necessity of optimization and standardization.