Anticancer effect of LS-HB-mediated photodynamic therapy on hepatocellular carcinoma in vitro and in vivo.

Photodynamic therapy (PDT) is a relatively safe way for disease diagnosis and treatment that is based on light and photosensitizers. A lack of excellent photosensitizers has become the main limitation for the widespread application of photodynamic therapy. LS-HB is a promising photosensitizer with a light absorption peak of 660 nm. AIMS: The present study aimed to investigate the anticancer effects of LS-HB-PDT on hepatocellular carcinoma and its underlying molecular mechanism. METHODS: In the present study, the MTT assay and xenograft tumor model experiment were used to evaluate its anticancer effects as well as its dark toxicity in hepatocellular carcinoma in vitro and in vivo. Reactive oxygen species assay kit was utilized to detect the reactive oxygen species production induced by LS-HB-PDT. RESULTS: In vitro, the MTT assay results revealed that LS-HB-PDT exhibited significant cytotoxic effects both in a drug- and light dose-dependent manner. The IC50 of LS-HB-PDT on hepatocellular carcinoma cells was 2.685 microg/ml. However, no dark cytotoxicity was observed at the LS-HB concentrations of 0-50 microg/ml, and no light-induced cytotoxicity was observed at the light (660 nm) dosages of 0-40 J/cm(2). Furthermore, reactive oxygen species could be induced after LS-HB-PDT in a drug- and light dose-dependent manner. In vivo experiment, the tumor inhibition ratio of tumor-bearing nude mice following LS-HB-PDT was enhanced with the drug and light dose increasing. Notably, tumors in 60.0% of mice disappeared after LS-HB-PDT (2 mg/kg; 100 J/cm(2)), and the tumor inhibition ratio reached 92.3%. Furthermore, the histological results revealed necrosis and thrombus in tumor tissue caused by LS-HB-PDT, which were not observed in the control, drug alone and light alone groups of mice. CONCLUSIONS: The present study indicated that LS-HB was a promising photosensitizer with excellent anticancer effects and low side effects. LS-HB-PDT induced reactive oxygen species damage in the cells directly and destroyed tumor blood vessels, thus leading to tumor tissue necrosis.