OBJECTIVETo investigate biological effect of hematoporphyrin derivative (HpD) photodynamic therapy (PDT) on in vitro cultured nasopharyngeal carcinoma (NPC) cell lines CNE2 and C666-1.

METHODSCNE2 and C666-1 cells cultured in vitro were incubated in a medium containing HpD at different concentrations (0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, and 4.0 microg/ml) for 4 h followed by exposure to different light doses (2, 5, 10, and 20 J/cm2) using a diode laser at 630 nm with power density of 20 mW/cm2. After 24 h of incubation with HpD-PDT, the survival rate of CNE2 and C666-1 cells were analyzed by MTT assay.

RESULTSHpD-PDT produced effective killing of CNE2 and C666-1 cells cultured in vitro, and the killing effects were positively correlated with HpD concentration and the irradiation dose. Exposure of CNE2 and C666-1 cells to irradiation dose of 20 J/cm2 resulted in the IC50 of 0.7 and 1.2 microg/ml, respectively (P<0.01). With the same HpD concentration and irradiation dose, the survival rate of C666-1 cells, however, was significantly higher than that of CNE2 cells (P<0.05).

CONCLUSIONHpD-PDT may result in effective killing of CNE2 and C666-1 cells cultured in vitro, although C666-1 cells are less sensitive to HpD-PDT than CNE2 cells.