A model of modifiedmeta-iodobenzylguanidine conjugated gold nanoparticles for neuroblastoma treatment

Abstract

Iodine-131meta-iodobenzylguanidine (131I-mIBG) has been utilized as a standard treatment to minimize adverse side effects by targeting therapies to bind to the norepinephrine transporter (NET) expressed on 90% of neuroblastoma cells. However, only a minority of patients who receive131I-mIBG radiotherapy have clinical responses, and these are usually not curative. In this study, novel ligand-conjugated gold nanoparticles (GNPs) based onmIBG were synthesized and evaluated biologically with neuroblastoma cellsin vitro. To induce specific internalization to the tumor cells and utilize it as a model for radioenhancement,127I-modifiedmIBG was successfully synthesized and grafted covalently to the surface of carboxylated PEG-GNPs. 49.28% of the novelmIBG derivative was grafted on carboxylated PEG-GNPs. The particles were stable and not toxic to the normal fibroblast cell line, L929, even at the highest concentration tested (1013NPs per mL) at 24, 48, and 72 h. Moreover, the cellular uptake of the model was decreased significantly in the presence of a NET inhibitor, suggesting that there was specific internalization into neuroblastoma cells line (SH-SY5Y)viathe NET. Therefore, this model provides useful guidance toward the design of gold nanomaterials to enhance the efficiency of131I-mIBG treatment in neuroblastoma patients. However, the investigation of radio-therapeutic efficiency after radioisotope131I substitution will be further conducted in a radiation safety laboratory using an animal model.