Apolipoprotein E3-mediated cellular uptake of reconstituted high-density lipoprotein bearing core 3, 10, or 17 nm hydrophobic gold nanoparticles

Abstract

We have developed a high-density lipoprotein (HDL)-based platform for transport and delivery of hydrophobic gold nanoparticles (AuNPs). The ability of apolipoprotein E3 (apoE3) to act as a high-affinity ligand for the low-density lipoprotein receptor (LDLr) was exploited to gain entry of HDL with AuNPs into glioblastoma cells. AuNPs of 3, 10, and 17 nm diameter, the latter two synthesized by phase transfer process, were solubilized by integration with phospholipids and apoE3, yielding reconstituted HDL (rHDL) bearing AuNPs. Ultraviolet–visible spectra of rHDL-AuNP indicated the presence of stable particles with surface plasmon band at ~530 nm. Transmission electron microscopy (TEM) of rHDL-AuNP revealed roughly spherical particles with AuNPs embedded in the core. The rHDL-AuNP particles displayed robust binding to the LDLr and were internalized by receptor-mediated endocytosis in glioblastoma cells. Confocal microscopy confirmed cellular uptake of AuNPs in the endosomal–lysosomal compartments, while TEM revealed intracellular aggregated AuNPs. Cell viability assay demonstrated that >85% of cells were viable with rHDL-AuNP treatment of 0.1–100 μg/mL for 24 hours. These findings are significant since they offer an effective means of delivering AuNPs across the cell membrane, which is particularly relevant in tumor cells that overexpress LDLr.

Progress in research on gold nanoparticles in cancer management

“…Biocompatible ligands are generally capable of reducing the cytotoxicity of AuNPs, and as shown by Deol et al, grafting of further dendrimers onto the surface of glutathione-modified AuNPs can improve their cell toxicity. [40]…”

“…The effects of hyperthermia on intracellular and extracellular processes include changes in signal transduction, induction of apoptosis, reduction of perfusion and tumor oxygenation and so on. [40] AuNRs or AuNSs have significant advantages for the absorption and scattering of near-infrared light (wavelengths from 650 to 900 nm). When exposed to electromagnetic radiation, especially near-infrared light, AuNPs can generate heat through surface plasmon resonance effects.…”

Reconfiguring Nature’s Cholesterol Accepting Lipoproteins as Nanoparticle Platforms for Transport and Delivery of Therapeutic and Imaging Agents

“…In a variation of this method, DMPC thin film, recombinant His-tag apoE3 and 3, 10 or 17 nm citrate-capped AuNP (5:2:3 w/w ratio) were co-sonicated in buffer and incubated for 16 h at 24 • C [64] (Figure 4D). The mixture was centrifuged at low speed, the bottom fraction washed several times with buffer, and His-tag/apoE3-associated AuNP captured by immobilized metal affinity chromatography.…”

“…ApoE3-rHDL Thin film hydration of cargo-lipid complex followed by co-sonication with apoE3 [18,39,63,171] Conventional method of preparing rHDL ApoE3-AuNP HDL Thin film hydration of AuNP-lipid complex followed by co-sonication with apoE3 [64,172] Noncovalent interactions between protein and NP, allowing retention of native interactions ApoE3 coated HSA Desolvation to form HSA NP, followed by conjugation with apoE3 [130][131][132]134] Non-lipidated formulation that allows trafficking of NP to the brain, possibly through LDLr and LRP1 on brain endothelial cells ApoE3-PBCA Incubation of apoE3 with PBCA NP, with or without polysorbate 80 [49] Lipid-free polymeric formulation of apoE3; capable of crossing the BBB ApoJ ApoJ-PBCA Incubation of apoJ with PBCA NP, with or without polysorbate 80 [49] Lipid-free polymeric formulation of apoJ…”

Hybrid lipid–nanoparticle complexes for biomedical applications

“…In an effort to target human brain glioblastoma cells, Chuang et al encapsulated AuNPs within the hydrophobic core of reconstituted high-density lipoprotein (HDL). 64 Tetradecanethiol-capped AuNPs with diameters of 3, 10, or 17 nm are co-sonicated with DMPC and recombinant apolipoprotein E3 (apoE3) in PBS solution resulting in the formation of hybrids. Preparation of hybrids using 3 nm AuNPs leads to the formation of 60-80 nm lipoproteins with many encapsulated nanoparticles.…”