title: Bombesin peptide conjugated gold nanocages internalize via clathrin mediated endocytosis.
abstract: The nature of interaction and mechanism of internalization of receptor-avid peptide nanoparticles with cells is not yet completely understood. This article describes the cellular internalization mechanism and intracellular trafficking of peptide conjugated receptor targeted porous Gold nanocages (AuNCs) in cancer cells. We synthesized and characterized a library of AuNCs conjugated with bombesin (BBN) peptide. Evidence of selective affinity of AuNC-BBN toward gastrin releasing peptide receptors (GRPR) was obtained using radiolabeled competitive cell binding assay. Endocytic mechanism was investigated using cell inhibitor studies and monitored using optical and transmission electron microscopy (TEM). Results show AuNC-BBN uptake in PC3 cells is mediated by clathrin mediated endocytosis (CME). Indeed, in the presence of CME inhibitors, AuNC-BBN uptake in cells is reduced up to 84%. TEM images further confirm CME characteristic clathrin coated pits and lysosomal release of AuNCs. These results demonstrate that peptide ligands conjugated to the surface of nanoparticles maintain their target specificity. This bolsters the case for peptide robustness and its persisting functionality in intracellular vehicular delivery systems.
authors.affiliation: Departments of †Bioengineering, ‡Radiology, ¥Medicine and §Chemistry, ⊥University of Missouri Research Reactor, and #International Center for Nano/Micro Systems and Nanotechnology, University of Missouri , Columbia, Missouri 65211, United States.
authors.forename: Dhananjay
authors.initials: D
authors.lastname: Suresh
authors.forename: Ajit
authors.initials: A
authors.lastname: Zambre
authors.forename: Nripen
authors.initials: N
authors.lastname: Chanda
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Hoffman
authors.forename: C Jeffrey
authors.initials: CJ
authors.lastname: Smith
authors.forename: J David
authors.initials: JD
authors.lastname: Robertson
authors.forename: Raghuraman
authors.initials: R
authors.lastname: Kannan
mesh_terms: D001839:Bombesin / Q000737:chemistry* / Q000378:metabolism*; D045744:Cell Line, Tumor; D002966:Clathrin / Q000378:metabolism*; D004705:Endocytosis; D011992:Endosomes / Q000378:metabolism; D006046:Gold / Q000737:chemistry*; D006801:Humans; D008247:Lysosomes / Q000378:metabolism; D049329:Nanostructures
chemical_list: D002966:Clathrin; D006046:Gold; D001839:Bombesin