Photodynamic action of LED-activated nanoscale photosensitizer in nasopharyngeal carcinoma cells

Abstract

Photodynamic therapy has been confirmed to an efficient therapeutic modality of malignant tumors. The aim of the present study was to explore the photodynamic action of LED-activated nanoscale photosensitizer-loading hypocrellin in nasopharyngeal carcinoma cells. Nasopharyngeal carcinoma cell line CNE2 cells were subjected to photodynamic therapy with hypocrellinloaded nanophotosensitizer. The uptake of the nanophotosensitizer in the CNE-2 cells was measured using a spectrophotometer and photodynamic toxicity was investigated 18 h after LED radiation treatment. Apoptosis was determined using flow cytometry with propidum iodine staining, and nuclear staining with Hoechst 33258. Active caspase-3 in the CNE2 cells was evaluated using flow cytometry with phycoerythrin (PE)-conjugated anti-active caspase-3 antibodies. The cellular uptake of the nanophotosensitizer in the CNE-2 cells reached optimal at 6 h. LED-activated nanophotosensitizer resulted in doseand light-dependent phototoxicity. Apoptotic rate 18 h after PDT increased to 34.32 ± 1.94% under the light energy of 1 J/cm2. Hoechest 33258 staining reinforced the findings above. Condensation of chromatin and nuclear fragmentations was found in many PDT-treated cells. The activated caspase-3 in the CNE2 cells significantly increased up to 43.90% when the CNE2 cells were exposed to the nanophotosensitizer for 6 h and then 1 J/cm2 irradiation. LED-activated nanophotosensitizer significantly killed the CNE2 cells and enhanced apoptosis and activated caspase-3 in the CNE2 cells. The hypocrellin-loaded nanophotosensitizer might be efficient photosensitizer and LED-activated nanophotosensitizer can be developed for treating nasopharyngeal carcinoma.