Photodynamic therapy with hexa(sulfo-n-butyl)[60]fullerene against sarcoma in vitro and in vivo

The hydrophilic molecular micellar hexa(sulfo-n-butyl)[60]fullerene (FC₄S), first synthesized in 1998 as a photosensitizer (PS) has been reported to exhibit high efficacy for singlet oxygen generation and antimicrobial photodynamic inactivation. The purpose of this study was to investigate the effects of photoactivated FC₄S for free radical generation and to mediate photodynamic therapy (PDT) of cancer in vitro and in vivo. The results demonstrated that following light irradiation, FC₄S produced singlet oxygen, but after addition of electron donors such as ferrocytochrome c or NADH, FC₄S also produced superoxide. The combination of FC₄S with light irradiation was able to induce cytotoxicity to human fibrosarcoma cells and murine sarcoma 180 cells in vitro. Cell-killing was proportional to fluence as well as FC₄S concentration. Photoirradiation by argon-ion laser after intraperitoneal injection of FC₄S also resulted in inhibition of S180 tumor growth in vivo (up to 80% reduction of tumor volume). Hematological and blood biochemistry parameters of the cancer-bearing mice were improved by PDT. Based on these findings, we conclude that FC₄S has a great potential as a nanomedicine in PDT for cancer.