Differences in sensitivity to HMME-mediated photodynamic therapy between EBV+ C666-1 and EBV− CNE2 cells

SummaryObjectivesThe aim of this study was to compare the sensitivity of hematoporphyrin monomethyl ether (HMME)-mediated PDT in the Epstein-Barr virus (EBV) positive and negative human nasopharyngeal carcinoma (NPC) cells.Methods and materialsThe intracellular uptake of HMME in C666-1 (EBV+) and CNE2 (EBV−) cells was quantitatively determined after incubating with different concentration of HMME. The subcellular localization of HMME was examined under a laser scanning fluorescence microscopy. The survival rate of C666-1 and CNE2 cells after HMME PDT was evaluated with clonogenic assay.ResultsThe EBV− CNE2 cells showed higher intracellular uptake of HMME and lower survival rate than EBV+ C666-1 cells. There was no significant difference in terms of subcellular localization of HMME between C666-1 and CNE2 cells.ConclusionThe sensitivity of EBV− CNE2 cells to HMME-mediated PDT was significantly higher than that of EBV+ C666-1 cells. The intracellular uptake of HMME plays a key role in determining the PDT sensitivity.