Effect of Peptide Derived from Scorpion Toxin on Enhanced Permeability of Doxorubicin Conjugated Gold Nanoparticles in HeLa and MDA-MB-231 Cells

Background: Cell penetrating peptides (CPPs) can enter a cell through the cell membrane, and used in the fields of drug delivery, gene therapy, and cancer therapy by their property transporting various molecules into cytoplasm. Gold nanospheres (GNSs) are a useful tool for molecular imaging, because they are not cytotoxic and have high solubility, excellent light scattering property and ease of synthesis. We constructed a drug delivery system by developing gold nanospheres conjugated to MCaUF1-9-C, a CPP derived from maurocalcine (MCa) scorpion toxin. We examined the applicability of this cell-selective anti-cancer drug delivery system by evaluating its cell-penetrating and cell death activities. Methods: Cell viability of HeLa and MDA-MB-231 cells, against 500 nanomolar concentration of doxorubicin (DOX)-conjugated gold nanoparticles (DOX-GNPs, and DOX-MCaUF1–9-C-GNP) were evaluated using MTT assay. Cell penetrability of MCaUF1-9-C peptide conjugated to gold nanoparticles investigated using of dark field imaging and atomic absorption spectroscopy (AAS). Results: HeLa cell viability was about 87% when treated with DOX-GNP and DOX-MCaUF1-9-C-GNP, whereas DOX-MCaUF1–9-C-GNP induced high cytotoxicity in MDA-MB-231 cells (30%). Dark field imaging demonstrated higher affinity of MCaUF1–9-C-GNP for the MDA-MB-231 cell compared with HeLa cells. Moreover, atomic absorption spectrometry data analysis showed that 33% of the total amounts of the applied MCaUF1–9-C-GNP were internalized in MDA-MB-231 cells.  Conclusion: These results demonstrated that peptide conjugated GNP would be a useful tool for the development of a cell-selective drug delivery system.