Combination-targeting to multiple endothelial cell adhesion molecules modulates binding, endocytosis, and in vivo biodistribution of drug nanocarriers and their therapeutic cargoes

Abstract

Designing of drug nanocarriers to aid delivery of therapeutics is an expanding field that can improve medical treatments. Nanocarriers are often functionalized with elements that recognize cell-surface molecules involved in subcellular transport to improve targeting and endocytosis of therapeutics. Combination-targeting using several affinity elements further modulates this outcome. The most studied example is endothelial targeting via multiple cell adhesion molecules (CAMs), which mimics the strategy of leukocytes to adhere and traverse the vascular endothelium. Yet, the implications of this strategy on intracellular transport and in vivo biodistribution remain uncharacterized. We examined this using nanocarriers functionalized for dual- or triple- targeting to intercellular, platelet-endothelial, and/or vascular CAMs (ICAM-1, PECAM-1, VCAM-1). These molecules differ in expression level, location, pathological stimulation, and/or endocytic pathway. In endothelial cells, binding of PECAM-1/VCAM-1-targeted nanocarriers was intermediate to single-targeted counterparts and enhanced in disease-like conditions. ICAM-1/PECAM-1-targeted nanocarriers surpassed PECAM-1/VCAM-1 in control, but showed lower selectivity toward disease-like conditions. Triple-targeting resulted in binding similar to ICAM-1/PECAM-1 combination and displayed the highest selectivity in disease-like conditions. All combinations were effectively internalized by cells, with slightly better performance when targeting receptors of different endocytic pathways. In vivo, ICAM-1/PECAM-1-targeted nanocarriers outperformed PECAM-1/VCAM-1 in control and disease-like conditions, and triple-targeted counterparts slightly enhanced this outcome in some organs. As a result, delivery of a model therapeutic cargo (acid sphingomyelinase, deficient in Niemann-Pick disease A-B) was enhanced to all affected organs by triple-targeted nanocarriers, particularly in disease-like conditions. Therefore, multi-CAM targeting may aid optimization of some therapeutic nanocarriers, where the combination and multiplicity of the affinity moieties utilized allow modulation of targeting performance.

How Carrier Size and Valency Modulate Receptor-Mediated Signaling: Understanding the Link between Binding and Endocytosis of ICAM-1-Targeted Carriers

“…Micro-sized carriers, such as filomicelles, rods, etc., have been shown to be suitable for drug delivery. 10, 11 Importantly, in order to achieve carrier formulations with different sizes but similar targeting valency, anti-ICAM and control IgG were mixed at different ratios on the coating mixture (see Materials and Methods), so that only the targeting valency on the carrier surface would vary while the total amount of antibodies (anti-ICAM + IgG) and the resulting modification to the carrier size would remain similar, as optimized previously, 23, 30 and shown here in Table 1.…”

“…23, 30 Briefly, ∼5 μM antibody was incubated for 1 h at room temperature with a particle concentration equivalent to ∼7×10 6 - 3×10 8 μm 2 of particle surface area/μL to allow surface adsorption, followed by removal of non-coated antibody by centrifugation at 13.8 g for 3 min. Coated carriers were resuspended at ∼1×10 6 to 2×10 7 μm 2 of carrier surface area/μL in phosphate-buffered saline containing 1% bovine serum albumin and sonicated to eliminate potential aggregates.…”

ATB0,+ transporter-mediated targeting delivery to human lung cancer cells via aspartate-modified docetaxel-loading stealth liposomes

“…[1][2][3] In this strategy, it is particularly important to find effective affinity moieties for increasing the interactions of targeting nanocarrier with tumor sites. A major focus in the design of targeted nanocarrier delivery systems is surface functionalization with affinity moieties to enhance the targeting site-specificity transport of nanotherapeutics.…”

Evaluation of receptor‐ligand mechanisms of dual‐targeted particles to an inflamed endothelium

“…Capture and firm arrest at the surface will depend on the kinetics of the LR engaged pair and the aggregate strength of those interactions. Particle ligand total receptor avidity and specificity must be balanced; excessive avidity can lead to off target binding and immune responses due to rapid opsonization of non‐native proteins, while insufficient LR avidity can result in minimal binding . The design of VTC ligands must correspond with receptors in the targeted disease state; a ligand for the immediate onset of disease may not function efficiently in a chronic response .…”