RESUMO
BACKGROUND: Photodynamic therapy (PDT) is a relatively novel modality for the treatment of cancer and some non-malignant lesions. PDT uses a photosensitive drug and light to destroy malignant cells. The aim of this study was to determine in vitro efficacy of Radachlorin-based PDT (Radachlorin-PDT) on human hepatocellular carcinoma (HCC). METHODS: The study used human liver cancer cells (HepG2) and normal liver cells (HFLF-PI4) to evaluate cell viability using the standard 2-(4, 5-dimethyl-2-thiazolyl)-3,5-diphenyl-2H-tetrazolium bromide (MTT) assay. The mechanism of cell death following Radachlorin-PDT was determined by DNA agarose gel electrophoresis and flow cytometry. RESULTS: Radachlorin without light irradiation had no toxic effect on HepG2 and HFLF-PI4 cells. Cell survival of HepG2 and HFLF-PI4 cells were decreased following PDT in a concentration-dependent manner. However, HepG2 cells were much more sensitive to Radachlorin-PDT than HFLF-PI4 cells. Radachlorin LD50 on HepG2 cells was 30µg/ml and 20µg/ml, 24h after exposure to doses of 5J/cm(2) and 15, or 25J/cm(2), respectively. Optimal Radachlorin and light dose to kill HepG2 cells with minimal effects on normal HFLF-PI4 cells were 100µg/ml and 15J/cm(2), respectively. Our results also showed that apoptosis is induced in HepG2 cells following Radachlorin-PDT. CONCLUSION: Our in vitro data suggest that the use of PDT with Radachlorin can be effective in the treatment of HCC.
