Solid Lipid Nanoparticles for Image-Guided Therapy of Atherosclerosis.

Although the application of nanotechnologies to atherosclerosis remains a young field, novel strategies are needed to address this public health issue. In this context, the magnetic resonance imaging (MRI) approach has been gradually investigated in order to enable image-guided treatments. In this contribution, we report a new approach based on nucleoside-lipids allowing the synthesis of solid lipid nanoparticles (SLN) loaded with iron oxide particles and therapeutic agents. The insertion of nucleoside-lipids allows the formation of stable SLNs loaded with prostacycline (PGI2) able to inhibit platelet aggregation. The new SLNs feature better relaxivity properties in comparison to the clinically used contrast agent Feridex, indicating that SLNs are suitable for image-guided therapy.

Amino acid-nucleotide-lipids: effect of amino acid on the self-assembly properties.

Hybrid amphiphiles composed of a lipid covalently linked to biomolecules are attracting considerable attention, owing to their unique physicochemical and biological properties. Herein, we have synthesized novel amino acid-nucleotide-lipids (ANLs), presenting phenylalanine and thymidine residues and saturated or unsaturated diacyl glycerol lipid moieties to investigate the effect of the specific aminoacid moieties on both aggregation properties and interactions of ANLs with single strand polyA RNA. Physicochemical studies (DLS, cryo-TEM, and small angle X-ray scattering) indicate that phenylanaline amino acids inserted at the 5' position of the nucleotide-lipids stabilize multilamellar systems, whereas unilamellar vesicles are formed preferentially in the case of nucleotide-lipids (NLs). Both NLs and ANLs exhibit weak interactions with complementary polyA RNA as revealed by isothermal titration calorimetry investigations. The multilamellar vesicles obtained with ANLs could be used as a versatile carrier, suitable for both hydrophobic and hydrophilic therapeutic molecules.

Cation Tuning of Supramolecular Gel Properties: A New Paradigm for Sustained Drug Delivery.

Hydrogels formed by the self-assembly of low-molecular-weight gelators (LMWGs) are promising scaffolds for drug-delivery applications. A new biocompatible hydrogel, resulting from the self-assembly of nucleotide-lipid salts can be safely injected in vivo. The resulting hydrogel provides sustained-release of protein for more than a week.

Lipid-oligonucleotide conjugates improve cellular uptake and efficiency of TCTP-antisense in castration-resistant prostate cancer.

Translationally controlled tumor protein (TCTP) has been implicated in a plethora of important cellular processes related to cell growth, cell cycle progression, malignant transformation and inhibition of apoptosis. Therefore, TCTP is now recognized as a potential therapeutic target in several cancers including prostate, breast and lung cancers. We previously showed that TCTP is overexpressed in castration-resistant prostate cancer (CRPC), and it has been implicated resistance to treatment. Recently, we developed TCTP antisense oligonucleotides (ASOs) to inhibit TCTP expression. However, the intracellular delivery and silencing activity of these oligonucleotides remains a challenge, and depend on the use of transfection agents and delivery systems. Here we show that lipid-modified ASO (LASOs) has improved penetration and efficiency in inhibiting TCTP expression in the absence of additional transfection agents, both in vitro and in vivo. Transfection with TCTP-LASO led to rapid and prolonged internalization via macropinocytosis, TCTP downregulation and significant decreased cell viability. We also show that lipid-modification led to delayed tumor progression in CRPC xenografts models, with no significant toxic effects observed.

First total synthesis of (+/-)-3-aza-11-oxa-1,3,5(10)-trieno steroids.

We set out to describe a new and versatile method for preparing 3-aza-11-oxa-1,3,5(10)-trieno steroids via an intramolecular Diels-Alder cycloaddition of o-quinodimethanes as the key step. The characteristic 1H and 13C NMR spectroscopic features of the synthesized compounds are reported.

pH-Cleavable Nucleoside Lipids: A New Paradigm for Controlling the Stability of Lipid-Based Delivery Systems.

Lipid-based delivery systems are an established technology with considerable clinical acceptance and several applications in human. Herein, we report the design, synthesis and evaluation of novel orthoester nucleoside lipids (ONLs) for the modulation of liposome stability. The ONLs contain head groups with 3'-orthoester nucleoside derivatives featuring positive or negative charges. The insertion of the orthoester function in the NL structures allows the formation of pH-sensitive liposomes. ONL-based liposomes can be hydrolyzed to provide nontoxic products, including nucleoside derivatives and hexadecanol. To allow the release to be tunable at different hydrolysis rates, the charge of the polar head structure is modulated, and the head group can be released at a biologically relevant pH. Crucially, when ONLs are mixed with natural phosphocholine lipids (PC), the resultant liposome evolves toward the formation of a hexadecanol/PC lamellar system. Biological evaluation shows that stable nucleic acid lipid particles (SNALPs) formulated with ONLs and siRNAs can effectively enter into tumor cells and release their nucleic acid payload in response to an intracellular acidic environment. This results in a much higher antitumor activity than conventional SNALPs. The ability to use pH-cleavable nucleolipids to control the stability of lipid-based delivery systems represents a promising approach for the intracellular delivery of drug cargos.

Efficient delivery of therapeutic small nucleic acids to prostate cancer cells using ketal nucleoside lipid nanoparticles.

A novel nucleoside lipid derived from dioleyl ketal was synthesized from uridine in three steps starting from dioleyl ketone. Electronic microscopy studies show that Ketals Nucleoside Lipids (KNL) self-assemble to form liposome-like structures in aqueous solutions. KNL is able to bind siRNA as demonstrated by electrophoresis experiment and standard ethidium bromide fluorescence displacement assay. Transfection assays of stable hepatic cell lines HupIRF, carrying a luciferase reporter gene demonstrate that KNL is able to transfect siRNA and exhibits protein knockdown more efficiently than its diester analog (DOTAU) and lipofectamine. Herein, we also report that KNLs are suitable transfecting reagents for the development of novel therapeutic approaches involving either siRNA or antisense oligonucleotide against human prostate cancer PC-3 cells resistant to chemotherapy.

Reduction-triggered delivery using nucleoside-lipid based carriers possessing a cleavable PEG coating.

A new non-ionic nucleoside based lipid (DOU-SS-PEG(2000), 5'-PEG(2000)-2',3'-dioleoyluridine) featuring uridine (U) as nucleoside and 2',3'-dioleyl (DO), as lipid moieties and a poly(ethylene glycol) (PEG) thiolytic cleavable spacer for in vitro delivery of drugs is described. The PEG detachable nucleotide lipid (DOU-SS-PEG(2000)) was prepared via a convergent synthesis starting from HS-PEG-OMe and uridine. The reduction-triggered delivery using the PEG detachable nucleoside lipid DOU-SS-PEG(2000) was evaluated on both liposomal and micellar objects. The liposomes were prepared from of a mixture of DOTAU (N-[5'-(2',3'-dioleoyl)uridine]-N',N',N'-trimethylammonium tosylate), the PEG detachable nucleoside lipid DOU-SS-PEG(2000) and DOPE-rhodamine (1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N-(lissamine rhodamine B sulfonyl ammonium salt) (60/40/0.1), whereas a mixture of 99.9% of DOU-SS-PEG(2000) and 0.1% of DOPE-rhodamine was used to prepare micelles. In addition, the supramolecular systems underwent a reduction-induced morphology transition from a micellar to vesicular states, which was characterized by DLS, zeta potential and TEM. The disulfide bond of the PEG chain was cleaved, by adding a reducing agent such as dithiothréitol (DTT), to expose the cationic surface of the liposome. The internalization of the resulting liposomes was facilitated as shown by the enhanced fluorescence signal observed in ovarian cancer cells (SKOV3) compared to the pegylated liposome. Likewise, when DTT was added to the mixture of cells incubated in the presence of DOU-SS-PEG(2000)/DOPE-rhodamine micelle, the fluorescence was observed in almost 100% of the SKOV3 cells.

Nucleoside-lipid-based nanoparticles for cisplatin delivery.

The use of delivery vehicles to selectively transport anticancer agents to tumors is very attractive to address both toxicity and efficacy issues. We report a novel approach based on hybrid nucleoside-lipids allowing the efficient encapsulation and delivery of cisplatin. We demonstrate that the nucleoside polar heads guide the self-assembly of the aggregates into highly loaded and stable nanoparticles. The nanoparticles, which are efficient vehicles for the delivery of cisplatin into different sensitive and resistant cancer cell lines, can overcome the disadvantages and limitations of drug delivery systems previously reported.

Water-soluble rhamnose-coated Fe3O4 nanoparticles.

Water-soluble biocompatible rhamnose-coated Fe(3)O(4) nanoparticles of 4.0 nm are obtained by covalent anchorage of rhamnose on the nanoparticles surface via a phosphate linker. These nanoparticles present superparamagnetic behavior and nuclear relaxivities in the same order of magnitude as Endorem that make them potential magnetic resonance imaging (MRI) contrast agents of a second generation, where the saccharides represent also specific ligands able to target lectins on skin cells.