Sonodynamically-induced Anticancer Effects of Polyethylene Glycol-Modified Carbon Nano Tubes
Nagahiko Yumita, Yumiko Iwase, Shin‐ichiro Umemura, Fu‐Shih Chen, Yasunori Momose
Abstract
BACKGROUND/AIM: Sonodynamic cancer therapy is based on the preferential uptake and/or retention of a sonosensitizing drug (sonosensitizer) in tumor tissues and the subsequent activation of the drug by ultrasound irradiation. In the present study, we investigated the sonodynamically-induced antitumoral effect with functionalized carbon nanotubes, such as poly-ethylene glycol-modified carbon nanotubes (PEG-modified CNTs). MATERIALS AND METHODS: Antitumor effects were evaluated using histological observation and assessing tumor growth following sonodynamic exposure to PEG-modified CNTs. RESULTS: The combined treatment of 100 μM PEG-modified CNT and ultrasound induced a 2-fold cytotoxicity. Sodium azide, which quenches singlet oxygen, significantly inhibited ultrasonication induced cell damage in the presence of PEG-modified CNTs. This suggests that singlet oxygen produced by the combined use of PEG-modified CNTs and ultrasound is involved in the induction of antitumoral effects. The destruction of tumor tissue was observed with the ultrasonic treatment in combination with PEG-modified CNTs, while neither the treatment with PEG-modified CNTs alone nor ultrasound alone caused any necrosis. CONCLUSION: These results indicate that PEG-modified CNT functions as a sonosensitizer and is effective for sonochemical treatment of solid tumors.