The tumoricidal effect of sonodynamic therapy (SDT) on S-180 sarcoma in mice

There are increasing data showing that sonodynamic therapy (SDT), which refers to a synergistic effect of drugs and ultrasound, is a promising new modality for cancer treatment. However, few clinical data on SDT have been published. One reason is the lack of suitable drugs for clinical SDT use. Recently a new sonosensitizing agent has been developed by SonneMed, LLC, referred to as SF1. In this study the effect of SDT with SF1 on S-180 sarcoma in mice was examined. The tumor bearing mice were allocated to the following groups: (1) sham-treatment (control, C); (2) ultrasound treatment (only ultrasound treatment, 1.2 mW/cm2 , without SF1, U); (3) SF1 treatment (SF1 20 mg/kg intraperitoneal [ip] without ultrasound treatment, S); and (4) SF1 + ultrasound treatment (SU). Following treatment, tumor volume was monitored. Tumor growth inhibition was seen only in group SU, and with increasing ultrasound intensity, the inhibitory effect was enhanced. Tumor growth inhibition was also visible even when covered by a barrier of bone. Pathological slices showed coagulated necrosis or metamorphic tissue with inflammatory reaction in the tumor taken from 2 to 36 hours after SDT. These data revealed that SDT with SF1 did inhibit growth of mouse S-180 sarcoma and the inhibitory effect was sound intensity dependent. SDT also induced some inflammation while it destroyed the tumor, indicative of a "vaccine" effect. SF1 shows great promise for clinical use in the future.