Interactions of egg yolk phosphatidylcholine with cholesteryl polyethoxy neoglycolipids containing N-acetyl-d-glucosamine

GLUT1 transporter-facilitated solid lipid nanoparticles loaded with anti-cancer therapeutics for ovarian cancer targeting

The therapeutics available for cancer treatment have the major hurdle of site-specific delivery of anti-cancer drugs to the tumor site and non-target specific side effects. The standard therapy for ovarian cancer still poses numerous pitfalls due to the irrational use of drugs affecting healthy cells. As an appealing approach, nanomedicine could revamp the therapeutic profile of anti-cancer agents. Owing to the low manufacturing cost, increased biocompatibility, and modifiable surface properties, lipid-based nanocarriers, particularly solid lipid nanoparticles (SLN), have remarkable drug delivery properties in cancer treatment. Given the extra-ordinary benefits, we developed anti-neoplastic (paclitaxel) drug-loaded SLN (PTX-SLN) and functionalized with N-acetyl-d-glucosamine (GLcNAc) (GLcNAc-PTX-SLN) to reduce the rate of proliferation, growth, and metastasis of ovarian cancer cells over-expressing GLUT1 transporters. The particles presented considerable size and distribution while demonstrating haemocompatibility. Using GLcNAc modified form of SLNs, confocal microscopy, MTT assay, and flow cytometry study demonstrated higher cellular uptake and significant cytotoxic effect. Also, molecular docking results established excellent binding affinity between GLcNAc and GLUT1, complimenting the feasibility of the therapeutic approach in targeted cancer therapy. Following the compendium of target-specific drug delivery by SLN, our results demonstrated a significant response for ovarian cancer therapy.

Specific interactions of mycosubtilin with cholesterol-containing artificial membranes

Mycosubtilin is a natural antimicrobial lipopeptide produced by Bacillus subtilis strains. It is characterized by its hemolytic and strong antifungal activities. Mycosubtilin interacts with the plasma membranes of sensitive cells. However, the molecular mechanisms of its biological activities have not been completely elucidated. Our purpose was therefore to analyze the interactions of mycosubtilin with biological membranes by using biomimetic membranes such as Langmuir monolayers and multilayers. Structural changes of mycosubtilin, involving its peptide backbone and the side chain of its tyrosyl residue, were observed when the lipopeptide was interacting with cholesterol-containing multilayers. The interactions of mycosubtilin with monolayers constituted by pure lipids and by phosholipid/cholesterol or phospholipid/sphingomyelin/cholesterol were also examined. An original behavior of mycosubtilin toward cholesterol-containing monolayers was found. However, this original behavior was lost when mycosubtilin was interacting with pure cholesterylacetate monolayers. This suggests the involvement of the alcohol group of cholesterol in mycosubtilin-cholesterol interactions within membranes. Moreover, mycosubtilin induced changes in the organization and morphology of cholesterol-containing monolayers, and large condensed domains with different levels of condensation appeared only in the case of DPPC/sphingomyelin/cholesterol monolayer.

Interactions of the natural antimicrobial mycosubtilin with phospholipid membrane models

Among the secondary metabolite lipopeptides produced by Bacillus subtilis, mycosubtilin is characterized by its strong antifungal activities. Even though its structure and its cellular target, the cytoplasmic membrane, have been determined, the molecular mechanisms of the biological activity of mycosubtilin have not been completely elucidated. In this work, the interactions between mycosubtilin and cytoplasmic membranes were modelled by using biomimetic systems such as Langmuir monolayers at the air-water interface and lipid multilamellar vesicles. The interactions of mycosubtilin with these biomimetic systems were examined, for the first time, by using specific techniques such as polarization modulation infrared reflection absorption spectroscopy, Brewster angle microscopy and high-resolution magic angle spinning NMR. Our findings indicate that mycosubtilin alone, at the air-water interface, forms a monolayer film and keeps its turn conformation. In the presence of DMPC, mycosubtilin binds to phospholipid monolayers, in a surface pressure-dependent manner. This binding results in the appearance of condensed domains which can be due to the formation of mycosubtilin clusters and/or to the lipopeptide aggregation with some phospholipid molecules and/or the formation of liquid-condensed domains of DMPC. Furthermore, in multilamellar vesicles, the mycosubtilin-DMPC interactions take place at the level of the aliphatic chains of the phospholipid because the phase transition temperature of DMPC decreased in the presence of mycosubtilin.

Self-organization of synthetic cholesteryl oligoethyleneglycol glycosides in water

Lectin-sugar recognition systems are of interest in the pharmaceutical field, especially for the development of drug carriers, tailored for selective delivery. This paper deals with the anhydrous and aqueous self-organization properties of a synthetic cholesteryl oligoethyleneglycol glycoside with the aim of their incorporation in liposomes. Successive phases (lamellar, R3m, Im3m, micelles) have been described depending on water content and temperature. As a result of the presence of sugar residues and their hydration ability, this glycolipid shows a large range of packing parameter with increasing water content. However, because of oligoethyleneglycol spacer, a slight dehydration has been observed with increasing temperature from 20 to 60 degrees C.

Cholesteryl oligoethyleneglycol glycosides: Fluidizing effect of their embedment into phospholipid bilayers

Glycosides of cholesteryl oligoethyleneglycols have been synthesized and embedded in liposome bilayers. Several methods as steady-state fluorescence polarization, differential scanning calorimetry, zeta potential, and agglutination have been used to describe the physicochemical outcome of the incorporation of these synthetic glycolipids within phospholipid layers. From calorimetry and fluorescence experiments, it is apparent that the glycolipids decrease the transition temperature of the bilayers in a more important extent than cholesterol. Furthermore, the thickness of the aqueous layer fixed around the liposome is independent of the presence of glycolipids, suggesting that their hydrophilic parts (tetraethyleneglycol spacer and sugar moiety) are not completely extended towards the aqueous phase. Nevertheless, an important and specific interaction has been observed between such glycosylated liposomes and vegetal lectins.