5-Aminolevulinic Acid-Based Sonodynamic Therapy Induces the Apoptosis of Osteosarcoma in Mice

OBJECTIVE Sonodynamic therapy (SDT) is promising for treatment of cancer, but its effect on osteosarcoma is unclear. This study examined the effect of 5-Aminolevulinic Acid (5-ALA)-based SDT on the growth of implanted osteosarcoma and their potential mechanisms in vivo and in vitro. METHODS The dose and metabolism of 5-ALA and ultrasound periods were optimized in a mouse model of induced osteosarcoma and in UMR-106 cells. The effects of ALA-SDT on the proliferation and apoptosis of UMR-106 cells and the growth of implanted osteosarcoma were examined. The levels of mitochondrial membrane potential (ΔψM), ROS production, BcL-2, Bax, p53 and caspase 3 expression in UMR-106 cells were determined. RESULTS Treatment with 5-ALA for eight hours was optimal for ALA-SDT in the mouse tumor model and treatment with 2 mM 5-ALA for 6 hours and ultrasound (1.0 MHz 2.0 W/cm2) for 7 min were optimal for UMR-106 cells. SDT, but not 5-ALA, alone inhibited the growth of implanted osteosarcoma in mice (P<0.01) and reduced the viability of UMR-106 cells (p<0.05). ALA-SDT further reduced the tumor volumes and viability of UMR-106 cells (p<0.01 for both). Pre-treatment with 5-ALA significantly enhanced the SDT-mediated apoptosis (p<0.01) and morphological changes. Furthermore, ALA-SDT significantly reduced the levels of ΔψM, but increased levels of ROS in UMR-106 cells (p<0.05 or p<0.01 vs. the Control or the Ultrasound). Moreover, ALA-SDT inhibited the proliferation of osteosarcoma cells and BcL-2 expression, but increased levels of Bax, p53 and caspase 3 expression in the implanted osteosarcoma tissues (p<0.05 or p<0.01 vs. the Control or the Ultrasound). CONCLUSIONS The ALA-SDT significantly inhibited osteosarcoma growth in vivo and reduced UMR-106 cell survival by inducing osteosarcoma cell apoptosis through the ROS-related mitochondrial pathway.