ABSTRACT
Angiogenesis is a dynamic process fundamental to the development of solid tumors. Epidermal growth factor-like domain 7 (EGFL7) is a protein whose expression is restricted to endothelial cells undergoing active remodeling that has emerged as a key mediator of this process. EGFL7 expression is associated with poor outcome in several cancers, making it a promising target for imaging or therapeutic strategies. Here, EGFL7 is explored as a molecular target for active neovascularization. Using a combinatorial peptide screening approach, we describe the discovery and characterization of a novel high affinity EGFL7-binding peptide, E7p72, that specifically targets human endothelial cells. Viral nanoparticles decorated with E7p72 peptides specifically target tumor-associated neovasculature with high specificity as assessed by intravital imaging. This work highlights the value of EGFL7 as a target for angiogenic vessels and opens the door for novel targeted therapeutic approaches.
ABSTRACT
The aim of this study is to investigate using nanoemulsion formulations as drug-delivery vehicles of paclitaxel (PX), a poor water-soluble anticancer drug. Two commercially available nanoemulsion fat formulations (Clinoleic 20% and Intralipid 20%) were loaded with PX and characterised based on their size, zeta potential, pH and loading efficiency. The effect of formulation on the cytotoxicity of PX was also evaluated using MTT assay. The droplet size of the Clinoleic emulsion increased from 254.1nm to 264.7nm when paclitaxel (6mg/ml) was loaded into the formulation, compared to the drug-free formulation. Similarly, the droplet size of Intralipid increased from 283.3 to 294.6nm on inclusion of 6mg/ml paclitaxel. The Polydispersity Indexes (PDIs) of all the nanoemulsion formulations (Clinoleic and Intralipid) were less than 0.2 irrespective of paclitaxel concentration indicating that all nanoemulsion formulations used were homogeneously sized. The pH range for the Clinoleic formulations (7.1-7.5) was slightly higher than that of the Intralipid formulations (6.5-6.9). The zeta potential of linoleic had a greater negative value than that of Intralipid. Loading efficiencies for paclitaxel were 70.4-80.2% and 44.2-57.4% for Clinoleic and Intralipid formulations, respectively. Clinoleic loaded with paclitaxel decreased the viability of U87-MG cell to 6.4±2.3%, compared to Intralipid loaded with paclitaxel (21.29±3.82%). Both nanoemulsions were less toxic to the normal glial cells (SVG-P12), decreasing the cell viability to 25-35%. This study suggests that nanoemulsions are useful and potentially applicable vehicles of paclitaxel for treatment of glioma.
Subject(s)
Emulsions/administration & dosage , Emulsions/chemistry , Glioma/drug therapy , Nanoparticles/administration & dosage , Nanoparticles/chemistry , Paclitaxel/administration & dosage , Paclitaxel/chemistry , Antineoplastic Agents/administration & dosage , Antineoplastic Agents/chemistry , Cell Line, Tumor , Chemistry, Pharmaceutical/methods , Drug Carriers/chemistry , Drug Delivery Systems/methods , Excipients/chemistry , Humans , Parenteral Nutrition/methods , Particle Size , Phospholipids/chemistry , Plant Oils/chemistry , Solubility , Soybean Oil/chemistryABSTRACT
Paclitaxel was loaded into licensed parenteral nutrition nanoemulsions (Clinoleic® and Intralipid®) using bath sonication, and the stability of the formulations was investigated following storage for two weeks at room temperature or at 4 °C. In general, Clinoleic droplets were smaller than Intralipid droplets, being around 255 and 285 nm, respectively, for blank and freshly loaded emulsions. Regardless of storage temperature, the Clinoleic exhibited a very slight or no increase in droplet size upon storage, whilst the droplet size of the Intralipid emulsion increased significantly. The droplet size of both emulsions was minimally affected by paclitaxel concentration within the range of 0, 1, 3 and 6 mg/ml. The pH of both emulsions markedly decreased upon storage at room temperature, which was possibly attributed to the production of fatty acids resulting from phospholipid hydrolysis. However, at 4 °C, the pH of Clinoleic emulsion was unaffected by storage or paclitaxel concentration while the Intralipid emulsion demonstrated a trend for pH reduction. Both nanoemulsions had a negative zeta potential, with the Clinoleic formulations having the highest charge, possibly explaining the better size stability of this emulsion. Overall, this study has shown that paclitaxel was successfully loaded into clinically licensed parenteral emulsions and that Clinoleic showed greater stability than the Intralipid.
