ABSTRACT
BACKGROUND: Indocyanine green (ICG) is a promising photosensitive agent for photodynamic therapy (PDT) of tumors. Encapsulating ICG dye in polymeric nanoparticles based on PEBBLE technology forming (ICG-PEBBLE) could improve the aqueous stability of the entrapped ICG molecules. The study objective is to investigate the PDT effect of free ICG-PEBBLE and its Anti-EGFR conjugate. METHODS: Skin squamous cell carcinoma was induced in CD1 mice by dimethylbenzanthracene (DMBA) and 12-O-tetradecanoyl-phorbol-13-acetate (TPA) followed by a PDT protocol for four weeks. RESULTS: PDT using ICG-PEBBLE or ICG-PEBBLE-Anti-EGFR decreased skin tumor sizes. Our findings revealed that the inflammatory mediators tumor necrosis factor (TNF-α), nitric oxide (NO), cycloxygenase-2 (COX-2) and 5-lipoxygenase (5-LOX), the angiogenic mediator vascular endothelial growth factor (VEGF), and proliferating cell nuclear antigen (PCNA) were decreased, while apoptosis, caspase-3 and histone acetylation were induced in tumor bearing groups after PDT using both of ICG-PEBBLE or ICG-PEBBLE-Anti-EGFR. CONCLUSION: The present study indicated the effectiveness of PDT using ICG-PEBBLE or ICG-PEBBLE-Anti-EGFR as an inhibitor modality for tumor size, apoptosis, angiogenesis and tumor inflammation. The conjugating of ICG-PEBBLE to anti-EGFR was found to be more effective in inhibiting VEGF and in increasing caspase-3 compared to free ICG-PEBBLE, but there were no other preferential PDT efficacy.
Subject(s)
Antibodies, Monoclonal/therapeutic use , ErbB Receptors/metabolism , Indocyanine Green/administration & dosage , Nanocapsules/therapeutic use , Photochemotherapy/methods , Skin Neoplasms/drug therapy , Skin Neoplasms/metabolism , Animals , ErbB Receptors/antagonists & inhibitors , Female , Mice , Nanocapsules/chemistry , Nanocapsules/ultrastructure , Photosensitizing Agents/therapeutic use , Polymers/chemistry , Siloxanes/chemistry , Skin Neoplasms/pathology , Treatment OutcomeABSTRACT
BACKGROUND: Photodynamic therapy (PDT) is a therapeutic modality involving the use of a photosensitizer agent activated by light of appropriate wavelength to selectively destroy tumor cells. Indocyanine green (ICG) is a promising photosensitive agent for PDT of tumor cells. The main disadvantage of using ICG in PDT is the instability of ICG in aqueous solutions. Encapsulating ICG dye in a biocompatible matrix based on PEBBLE technology showed an improvement of aqueous stability comparing with free ICG dye. The main objective of this study is to investigate the photodynamic effect of ICG-ormosil PEBBLEs on two different cell lines: human breast adenocarcinoma cells (MCF-7) and hepatocellular carcinoma cells (HepG2). METHODS: ICG-embedded ormosil PEBBLEs were synthesized based on a sol-gel process, and characterized by transmission electron microscopy and other fluorescence tests. The cell viability was evaluated by MTT and trypan blue assays. Apoptosis, necrosis, and DNA damage (comet assay), were evaluated by fluorescence microscopic tests. RESULTS: The results declared that ICG-ormosil PEBBLEs and free ICG both have the same cytotoxic and phototoxic effect on MCF-7 and HepG2 cell lines, where the apoptotic mode of cell death is preferentially occurred in case of PDT using ICG-ormosil PEBBLEs. Both ICG and ICG-ormosil PEBBLEs induced DNA damage after laser exposure. These results would suggest that entrapping ICG in Polymeric nanoparticles forming ICG-ormosil PEBBLEs improve the aqueous stability of the photosensitizer and in the same time retain its photodynamic activity, suggesting that it is preferred to use ICG-ormosil PEBBLEs instead of free ICG dye.
