Hypocrellin B-encapsulated nanoparticle-mediated rev-caspase-3 gene transfection and photodynamic therapy on tumor cells

Gene therapy and photodynamic therapy are two kinds of important therapeutic strategies for treating malignant tumors. In order to explore the combined effects of gene therapy and PDT on tumor cells, rev-caspase-3 gene was transfected into the tumor model CNE2 cells using hypocrellin B-encapsulated nanoparticle (nano-HB) as a carrier. The transfected CNE2 cells were then irradiated by light from a LED source and the survival rate was investigated 18 h after PDT. Apoptosis was analyzed by a flow cytometer with propidium iodine (PI) staining and the active caspase-3 expression was measured using flow cytometry with phycoerythrin (PE)-conjugated anti-active caspase-3 antibody. The result from the flow cytometer showed that the level of the activated caspase-3 significantly increased up to 63.10% in the transfected CNE2 cells. The survival rate 18 h after gene transfection alone and nano-HB-mediated PDT was 96.6 +/- 2.07%, 72.6 +/- 4.15%, respectively. However, the survival rate of the transfected CNE2 cells 18 h after LED exposure significantly decreased to 50.6 +/- 5.98% under the light energy of 4 J/cm(2). Apoptotic rate 18 h after the combination of gene transfection and PDT increased up to 24.65%. Our findings demonstrated that nano-HB could significantly enhance the tranfection efficiency of rev-caspase-3 gene in the CNE2 cells. LED irradiation could effectively kill the treated CNE2 cells and induce apoptosis, suggesting hypocrellin B-encapsulated nanoparticle as an efficient gene carrier and a novel photosensitizer. The combination of gene therapy and PDT using nanoparticle as a mediator can be developed for treating nasopharyngeal carcinoma. (C) 2010 Elsevier B.V. All rights reserved.