Category: Preclinical Development
Purpose: Melanoma is the major cause of death for skin cancer patients, despite only making up 1% of all skin cancer cases. The number of melanoma patients is still increasing fueling the necessity to find alternative strategies to current conventional approaches for melanoma treatment. Recently, silver nanoparticles (AgNP) have been reported to have anti-tumor activity against many tumor cell lines, including melanoma. However, the effect of AgNP on the growth of this cancer has not been thoroughly investigated. In the studies presented here, we inspected the effect of AgNP on the growth of melanoma cells both in vitro and in vivo.
Methods: AgNP, sized around 10 nm, were synthesized by a chemical reduction method. They were further characterized using UV-visible spectroscopy and transmission electron microscopy (TEM) to confirm the presence of AgNP. The B16.F10 melanoma cell line used was purchased from ATCC. Prestoblue [Thermofisher Scientific] assays were used to test the cytotoxicity of AgNP against the B16.F10 cell line. Clonogenic assays were also performed to investigate the anti-proliferative effect of AgNP on the B16.F10 cell line. For the in vivo study, C57BL/6 mice were used as the model and B16.F10 melanoma cells were subcutaneously injected into the right lower flank of the mouse. Note that the concentration of AgNP used in both in vitro and in vivo study was measured using ICP-MS.
Results: The result from the Prestoblue assay indicated that the viability of B16.F10 cells decreased as the concentration of AgNP increased. The results from the clonogenic assay further suggested the anti-proliferative ability of AgNP on B16.F10 cells. For the in vivo study, the tumor growth appeared to be slower in AgNP-treated mice, comparing to the naïve (untreated) or the succinate buffer-treated mice (vehicle). Using Tukey-Kramer test, the p-values when comparing the naïve and AgNP-treated groups and the succinate and AgNP-treated groups were 0.2084 and 0.0420, respectively. Note that the p-value between naïve and succinate was 0.8781.
Conclusion: AgNP can inhibit the growth of B16.F10 cells in a dose-dependent manner as determined by the Prestoblue and clonogenic assays. The in vivo results indicated the tendency of AgNP to prolong the survival of melanoma-implanted mice.
Aliasger Salem– Professor, College of Pharmacy, University of Iowa, Iowa City, Iowa