Sonodynamically-induced antitumor effect of mono-l-aspartyl chlorin e6 (NPe6)

The sonodynamically-induced in vitro and in vivo antitumor effects of mono-l-aspartyl chlorin e6 (NPe6) was investigated.Both in vitro and in vivo antitumor effects were tested in combination with ultrasound at 2 MHz.The rate of ultrasonically-induced damage on isolated sarcoma 180 cells in air-saturated suspension was enhanced two-fold with 80 μM NPe6. The co-administration of 25 mg/kg NPe6 followed by ultrasonic exposure at 2 MHz suppressed the growth of implanted colon 26 cell tumors at an intensity at which ultrasound alone showed only a slight antitumor effect.These in vitro and in vivo results suggest that NPe6 is a potential sensitizer for sonodynamic tumor treatment. The enhancement of cell damage by NPe6 was significantly inhibited by histidine, which may suggest reactive oxygen species plays a primary role in sonodynamically-induced antitumor effect.