5-ALA-PDT Efficacy For C666-1and CNF2Nasopharyngeal Carcinoma Cell Lines

Nasopharyngeal carcinoma (NPC) is a common head and neck cancer that has the highest morbidity in Southern China. Its pathogenesis is closely related to the infection of Epstein-Barr virus (EBV). At present, only one EBV-positive (EBV+) NPC cell line C666-1in long-term culture has been reported. However, we discovered that the long-term passaged C666-1cells could no longer carry EBV. In order to better understand the mechanisms of NPC-PDT, we study the differences in intracellular concentration and subcellular localization of the endogenous PpIX, as well as the photodynamic effects among EBV-C666-1, EBV-CNE2and EBV+C666-1cell lines using5-aminolevulinic acid (5-ALA) as a model photosensitizer. With analyzing and discussing the results, we expect to provide the theory for the effects of EBV in the nasopharyngeal carcinoma photodynamic therapy.It turns out that the EBV+C666-1’s absorption ability of5-ALA-PpIX is higher than that of EBV-C666-1. The three cell lines are different in the ability of generation of PpIX, and the same cell line produces the amount of PpIX after absorbing5-ALA in different growing phases has significant variation too.5-ALA-PpIX is mainly distributed in the mitochondria of C666-1and the cell membrane of CNE2. In the same experimental condition, The effect of5-ALA-PDT for EBV+C666-1cells is the most obvious, with a low energy density0.9J/cm2irradiated, the cell survival rate only29%. In addition, The survival rate of EBV-C666-1cell is lower than that of CNE2cell after24h or48h of cell-culturing with PDT experiment, however, it is higher after72h.The tumor malignant degree of EBV-C666-1cell maybe lower than that of EBV+C666-1, which effects its selective absorption of5-ALA-PpIX.5-ALA is a good exogenous photosensitive drug for the treatment of Nasopharyngeal carcinoma, and the concentration and distribution of5-ALA-PpIX in cells is the critical factor that affecting the effects of5-ALA-PDT.