(306e) Targeted Silver Nanoparticles for Selective Cytotoxicity of Tumorigenic Endothelial Cells

Silver nanoparticles (AgNPs) have widely documented cytotoxic properties that are influenced by size, shape, and surface chemistry. AgNPs introduced to a biological environment interact with proteins and cell membrane receptors, which influence cell uptake, gene expression and cytotoxicity. Thus, controlling the cell-NP interface has important implications in the application of AgNPs for therapeutic purposes. For example, AgNPs can be engineered to selectively interact with specific cell types by surface functionalization with biomimetic targeting moieties. The objective of this study was to investigate the effects of AgNP exposure on the cytotoxicity of hemangioendothelioma (EOMA) cells, which are a tumorigenic endothelial cell line. Cells were incubated with citrate stabilized AgNPs of variable diameter (10-100μm) at a 0.01 mg/mL. Absorbance based assays revealed that higher cell uptake and cytotoxic responses correlated with decreased particle size. Alternatively, AgNPs were functionalized with cyclic RGD peptides by either physisorption or covalent conjugation to target α_vβ₃-integrin receptors on the cell membrane of EOMA cells. The presence of α_vβ₃-integrin expression in EOMA cells was demonstrated via RT-PCR and confocal microscopy. EOMA cells exposed to RGD-AgNPs in serum-containing media did not show a significant enhancement in cell uptake or cytoxocity relative to non-binding RAD control peptides. In contrast, RGD-AgNP fabricated with NHS-ester reaction chemistry elicited a significant increase in cytotoxicity relative to non-targeted controls. DCFDA and ELISA assays suggest that enchanced cytotoxicity is correlated with increased ROS generation and an upregulation of inflammatory cytokine production. These results demonstrate the utility of functionalizing AgNP with RGD peptides for selective cytotoxicity of α_vβ₃-integrin expressing EOMA cells. Future work will be aimed at further elucidating the molecular mechanisms of RGD-AgNP induced cytotoxicity in EOMA cells.