Resveratrol Nanostructured Lipid Carrier for targeted delivery to breast cancer

Abstract

Background: Breast cancer remains a prominent cause of mortality and morbidity in the female population. Despite advances in terms of novel compounds, exhibiting chemotherapeutic activity successful delivery remains challenging. Particulate-based system such as Nanostructured Lipid Carriers (NLCs) a new generation carrier allow encapsulation of drug and targeting of desired tissue. Resveratrol (RES) is a chemotherapeutic drug limited by its physiochemical properties (i.e. poor solubility and bioavailability), encapsulation into NLCs is potentially viable solution to the aforementioned issues.
Aim: The main aim of the present work is to develop a nanostructured lipid carriers based drug delivery system of RES in order to overcome its physicochemical and pharmacokinetic limitations and impart suitable functionalities for targeting breast cancer cells.
Methods: Box-Behnken experimental design (BBD) was used to understand the effect of three independent factors (amount of liquid lipid, amount of drug and surfactant concentration) and interactions between these factors for each of the six liquid lipids on the selected response variables particle size (PS), polydispersity index (PDI), zeta potential (ZP), drug encapsulation efficiency (%EE), and drug loading (%DL). The formulated resveratrol nanostructured lipid carriers (RES-NLCs) were subjected to a series of physicochemical characterization including particles size, zeta potential measurements, in-vitro drug release while the morphology of RES-NLCs was confirmed through various microscopic methods, differential scanning calorimetry, x ray diffraction and Fourier transfer infrared studies was carried out in order to understand the interactions between RES and the components of the formulation. Undertake stability studies for the formulated RES-NLCs, at various storage conditions in order to select the most stable formulation and take it for further functionalization with targeting ligands hyaluronic acid; HA-NLCs, folic acid; FA-NLCs and dual targeting system using both hyaluronic acid and folic acid; HAFANLCs, and optimization of ligand density and quantify the amount of amine groups present on the surface on RES-NLCs.
The efficacy of RES-NLCs was demonstrated through various in-vitro cell lines studies carried on three breast cancer cell lines entailed: MCF-7, MCF-10A and MDAMB-231 cells. Finally, the permeability of the formulations was evaluated through Caco-2 monolayer and Caco2/HT29 co-culture cell lines in order to understand the intestinal barrier transport mechanism.
Results: The employed Box Behnken design resulted in the formulation of particles which were <100nm in size, PDI <0.3, a negative surface charge (-24), high entrapment efficiency (91-99%) and drug loading of 3-4%, with tuneable characteristics within the design space. Differential scanning calorimetry and x-ray diffraction indicated amorphous nature of the drug in nanoparticles indicating its entrapment. Upon exposure to acidic medium (pH 1.2), <20% drug release was observed in 4 hours, with 100% drug release observed upon the increase of pH to 5 over a period of 24 hours.
Upon stability testing of NLCs, nanoparticles formulated with GTO as a liquid lipid showed good stability and therefore was taken forward for further PEGylating and surface modification with three ligands; hyaluronic acid, folic acid and combination of both ligand in order to impart targetability for breast cancer cells. Surface modification drastically reduced drug release to < 2 % at pH 1.2, however at pH 5, drug release time plots indicated slower overall release from the surface modified NLCs.
In-vitro cytotoxicity studies showed that RES-NLCs were effective against both non-TNBC; MCF-7 and TNBC; MDAMB-231 breast cancer cell lines. Dual ligand appended nanoparticles showed 2.7 folds higher toxicity in MCF-7 and 3.6 fold higher toxicity in MDAMB-231 cells as compared to RES-NLC-GTO-PEGS40 demonstrating its potential for treatment in the aggressive triple negative cancer. None of the RES-NLCs formulations containing different liquid lipids or their blanks were cytotoxic to healthy MCF-10A cells demonstrating safety of the formulations. All bare, PEGylated and surface modified RES-NLCs showed time dependent cellular uptake on both MCF-7 and MDAMB-231 cell lines. Surface modification lead to 3 fold increase in the cellular uptake confirming the targetability potential of the ligand appended formulations toward overexpressed receptors on the surface of both cancer MCF-7 and MDAMB-231 cells.
Upon examination of endocytosis mechanisms when cells were treated with the formulations, it was noted that two mechanisms were prominent. Clathrin-mediated endocytosis was identified as the primary method of endocytosis for all formulations. However, specifically for surface modified NLCs receptor mediated endocytosis was also found to be responsible for uptake of nanoparticles.
Bidirectional transport study demonstrated that the permeability was sensitive to the type of liquid lipid incorporated with the highest permeability exhibited for PGML based formulation, when studied using a Caco-2 monolayer. On comparison to Caco-2/HT29 co-culture free resveratrol showed higher permeability when compared to the formulated NLCs.
Conclusion: The aforementioned research has demonstrated that resveratrol NLCs are a viable potential product for use in the treatment of breast cancer, exhibiting high versatility and specificity.