The effect of multistage nanovector targeting of VEGFR2 positive tumor endothelia on cell adhesion and local payload accumulation

Abstract

Nanovectors are a viable solution to the formulation of poorly soluble anticancer drugs. Their bioaccumulation in the tumor parenchyma is mainly achieved exploiting the enhanced permeability and retention (EPR) effect of the leaky neovasculature. In this paper we demonstrate that multistage nanovectors (MSV) exhibit rapid tumoritropic homing independent of EPR, relying on particle geometry and surface adhesion. By studying endothelial cells overexpressing vascular endothelial growth factor receptor-2 (VEGFR2), we developed MSV able to preferentially target VEGFR2 expressing tumor-associated vessels. Static and dynamic targeting revealed that MSV conjugated with anti-VEGFR2 antibodies displayed greater than a 4-fold increase in targeting efficiency towards VEGFR2 expressing cells while exhibiting minimal adherence to control cells. Additionally, VEGFR2 conjugation bestowed MSV with a significant increase in breast tumor targeting and in the delivery of a model payload while decreasing their accumulation in the liver. Surface functionalization with an anti-VEGFR2 antibody provided enhanced affinity towards the tumor vascular endothelium, which promoted enhanced adhesion and tumoritropic accumulation of a reporter molecule released by the MSV.

The Impact of Nanoparticle Protein Corona on Cytotoxicity, Immunotoxicity and Target Drug Delivery

“…Over the past decade, various nanomaterials have been designed for delivery of drugs [76], DNA [77] and imaging agents [78]. These nanocarriers were designed in an attempt to: increase drug bioavailability and avoid drug inactivation, which is particularly important in the case of poorly soluble compounds (i.e., paclitaxel) [79], and in the case of macromolecules sensitive to degradation by blood proteases/peptidases or nucleases, (i.e., proteins/peptides or DNA/RNAbased therapeutics) [80]; minimize side-effects due to a nonspecific body distribution of the drug and to the high amount of drug commonly used [81]; and selectively deliver the payload to the affected area, thereby increasing its tissue accumulation [82].…”

Multistage vector delivery of sulindac and silymarin for prevention of colon cancer

“…Centrifugation was used to remove unloaded micelles. The MSVs were labeled with fluorescent dye and anti-meprin A antibodies following a similar strategy as previously reported [34]. Briefly, rabbit polyclonal meprin A subunit α (MEP1A) and meprin A subunit β (MEP1B) antibodies were mixed with Alexa Fluor 555 (Invitrogen) and 2-iminothiolane hydrochloride (Traut's Reagent, Thermo Scientific, 2 mg/ml) in phosphate buffer (PB, 10 mM, pH 7.5) at 4°C for 1 h. The micelle-loaded MSVs were then mixed with the fluorescently labeled antibodies for 2 h at 4 °C, enabling the sulfhydryl groups on the meprin A antibodies (enriched using Traut's reagent) to bind to the maleimide groups on the SMCC-MSVs.…”

“…Although molecular targeting strategies are unable to steer the movement of particles within the body, they can improve the retention of particles as they randomly pass through the target region. Previously, the MSV has been functionalized with targeting ligands against cancer vasculature [34] and malignant lesions in the bone marrow [20,35], resulting in a threefold and fivefold increase in tumor accumulation, respectively. In the case of cancer vasculature targeting, the MSV was functionalized with an antibody specific for vascular growth factor receptor 2 (VEGFR2), which is selectively expressed on tumor blood vessels [34].…”

“…Previously, the MSV has been functionalized with targeting ligands against cancer vasculature [34] and malignant lesions in the bone marrow [20,35], resulting in a threefold and fivefold increase in tumor accumulation, respectively. In the case of cancer vasculature targeting, the MSV was functionalized with an antibody specific for vascular growth factor receptor 2 (VEGFR2), which is selectively expressed on tumor blood vessels [34]. Additionally, the MSV was conjugated with an aptamer for E-selectin, which is preferentially present on bone marrow endothelium [20,35].…”

Multistage vector (MSV) therapeutics

“…The RGD (arginine-glycine-asparagine) peptide, which is a known ligand for α v β 3 and α v β 5 integrins [97, 99], was used as a targeting agent for MSVs, consequently resulting in a twofold increase in tumor accumulation in a mouse model of melanoma [77]. Similarly, in a murine model of orthotopic breast cancer, conjugation with an antibody against VEGFR2 led to a threefold increase in MSV tumor accumulation [100]. Taken together, these in vivo studies indicate a clear improvement in MSV tumor accumulation as a result of molecular targeting.…”