Photothermal therapeutic effect of PEGylated gold nano-semicubes in chemically-induced skin cancer in mice

Abstract

Background: The photothermal properties of gold nanoparticles (GNPs) are promising therapeutic modality for cancer. The study objective is to evaluate the therapeutic effect of the prepared PEGylated gold nano-semicubes (PEG-GNSCs) in skin cancer. The synthesized PEG-GNSCs were intermediate between cubic and rod shapes (low aspect ratio- rods).

Methods: In vitro toxicity was investigated in human skin melanoma Sk-Mel-28 cells, and skin squamous cell carcinoma was induced in CD1 mice by dimethylbenzanthracene (DMBA) and 12-O-tetradecanoyl-phorbol-13-acetate (TPA).

Results: The calculated IC₅₀ in Sk-Mel-28 cells was 3.41μg/ml of PEG-GNSCs, in presence of laser exposure. Photothermal therapy using laser-stimulated PEG-GNSCs resulted in inhibited volume of skin tumors. Our findings indicated that the inflammatory mediators, nitric oxide and cycloxygenase-2, were inhibited in mice after being treated with low and high doses of PEG-GNSCs, accompanied with laser exposure. However, the tumor necrosis factor -α was markedly elevated, while there was no change in 5-lipoxygenase. The pro-angiogenic factor vascular endothelial growth factor was inhibited, while histone acetylation and apoptosis were induced in tumor-bearing groups, after being treated with laser-stimulated PEG-GNSCs.

Conclusion: The present study indicated the promising photothermal therapeutic effect of laser-stimulated PEG-GNSCs as an effective modality to inhibit the tumor growth, the angiogenesis and partially the inflammation.

Keywords: COX-2; Nitric oxide; PEGylated gold nano-semicubes; Skin cancer; TNF-α; VEGF.