EXTH-55. Targeting Malignant Gliomas with 5-ALA Sonodynamic Therapy: In Vitro Efficacy, HIFU-Delivered In Vivo Treatment, and Berberine Potentiation

OBJECTIVE The high invasiveness of malignant gliomas frequently causes local tumor recurrence, requiring novel therapies targeting infiltrating glioma cells. This study examined the cytotoxic effects of sonodynamic therapy (SDT) combined with the sonosensitizer 5-aminolevulinic acid (5-ALA) on malignant gliomas in vitro and in vivo. Additionally, to enhance SDT effects, the potential of berberine (BBR) as a 5-ALA-fluorescence enhancer for clinical practice was investigated. METHODS Researchers evaluated 5-ALA-SDT’s cell-killing effects on U87 and U251 glioma cells and U251Oct-3/4 glioma stem-like cells (GSCs) in vitro. They analyzed apoptosis (programmed cell death) and measured intracellular reactive oxygen species (ROS). In vivo, the team studied the impact of 5-ALA-SDT with high-intensity focused ultrasound (HIFU) on tumor growth and survival in mice with transplanted gliomas, also examining brain tissue histologically. Additionally, they assessed BBR’s ability to increase 5-ALA-induced fluorescence in glioma cells and GSCs using flow cytometry. RESULTS In vitro, 5-ALA-SDT inhibited cell growth and induced apoptosis. The therapy increased ROS levels, and blocking ROS eliminated its cytotoxic effects. In vivo, 5-ALA-SDT with HIFU significantly prolonged the survival of tumor-bearing mice (p < 0.05). Histological analysis showed tumor necrosis in the HIFU focal area and apoptosis in the surrounding (perifocal) tumor cells. Crucially, normal brain tissue near the ultrasound field remained undamaged. BBR markedly enhanced 5-ALA-fluorescence, with a more pronounced effect in GSCs than in regular glioma cells. CONCLUSIONS 5-ALA-SDT exhibited cytotoxicity towards malignant gliomas. ROS generation by SDT is thought to promote apoptosis of glioma cells. 5-ALA-SDT with HIFU induced tumor necrosis in the focal area and apoptosis in the perifocal area of the HIFU-irradiated field. These results suggest that 5-ALA-SDT with HIFU may offer a less invasive and tumor-specific therapy for both tumor masses and infiltrating tumor cells in malignant gliomas. Furthermore, berberine is anticipated to have potential as an enhancer for SDT.