Introduction: Photodiagnosis (PD) with 5-aminolevulinic acid (5-ALA) is useful to detect malignant glioma tissue during surgery. On the other hand, photodynamic therapy (PDT) with 5-ALA is not yet popular for malignant gliomas, although PDT is widely used for skin or gastrointestinal cancers. One of the problems of PDT for gliomas is the limit of penetrating distance of light. Since glioma grows invasively into deep tissue, its effect does not reach the peripheral of the tumor. Ultrasound instead can conduct its energy into the deep tissue with less attenuation and is known to activate photosensitizing drug like light. We have been investigating its application for glioma treatment and report the different effects on two glioma cell lines.
Methods: Two human malignant glioma cell lines (U-87 MG, SNB-19) were cultured in exponential growth phase. The glioma cells were treated with 5-aminolevulimic acid (5-ALA) for 4 hours and then enclosed in plastic tubes. Ultrasonic device UST-770 (ITO Co., Ltd.) was used for all experiments. Ultrasonication (US) was performed at the condition of 2.0W/cm2, 1.0MHz, 5min and the depth of 3 cm. As control, 5-ALA (-) or US(-) groups were set. The number of cells was counted immediately after SDT and after 48 hour-incubation.
Results: The SDT with 5-ALA showed suppressive effect (approximately 15% by comparison with a control data) on U-87 MG. Whereas no effect was seen in other groups of U-87 MG, and all groups of SNB-19.
Conclusions: SDT with 5-ALA has the potential as an option for treatment of malignant glioma. The conditions have to be investigated for its stable effectiveness. The mechanism of action should also be elucidated to understand the differential effects on each cell lines.
Patient Care: Sonodynamic therapy with 5-aminolevulic acid has the potential as an option for treatment of malignant glioma.
Learning Objectives: By the conclusion of this session, participants should be able to: 1) Describe the importance of sonodynamic therapy, 2) Discuss, in small groups, 5-aminolevulinic acid, 3) Identify an effective treatment of sonodynamic therapy with 5-aminolevulinic acid