In vivo biodistribution and oxygenation potential of a new generation of oxygen carrier.

Natural giant extracellular hemoglobins (Hbs) from polychaete annelids are currently actively investigated as promising oxygen carriers. Their powerful oxygenating ability and their safety have been demonstrated in preclinical studies, motivating their development for therapeutic and industrial applications. HEMARINA-M101 (M101) is derived from the marine invertebrate Arenicola marina. It is formulated as a manufactured product designated HEMOXYCarrier(®) (HEMARINA SA, France). The aim of the present study was to unveil the fate of M101 after a single intravenous (i.v.) injection in mice. For this purpose, M101 was tagged with a far-red fluorescent dye. Repeated non-invasive fluorescent imaging revealed a rapid diffusion of M101 in the whole body of animals, reaching all the examined organs such as brain, liver, lungs and ovaries. Functional M101 was circulating in bloodstream for several hours, without inducing any obvious side-effects. Last, a single i.v. injection of M101 in mice bearing human-derived subcutaneous tumors demonstrated the ability of this Hb to reduce hypoxia in poorly vascularized tissues, thus supporting the biological relevance of M101 oxygen release to vertebrate tissues. Altogether, these results further encourage the development of M101 as an oxygen carrying therapeutic.

Effects of silencing the RET/PTC1 oncogene in papillary thyroid carcinoma by siRNA-squalene nanoparticles with and without fusogenic companion GALA-cholesterol.

BACKGROUND: RET/PTC1 is the most prevalent type of gene rearrangement found in papillary thyroid carcinoma (PTC). Previously, we introduced a new noncationic nanosystem for targeted RET/PTC1 silencing by efficient delivery of small interfering RNA (siRNA) using the "squalenoylation" approach. With the aim of improving these results further, we designed new squalenoyl nanostructures consisting of the fusogenic peptide GALA-cholesterol (GALA-Chol) and squalene (SQ) nanoparticles (NPs) of siRNA RET/PTC1. METHODS: The siRNA RET/PTC1-SQ bioconjugate was synthesized. The corresponding NPs were prepared with or without GALA-Chol by nanoprecipitation and then characterized for their size and zeta potential. The effects of NPs on BHP 10-3 SCmice and TPC-1 cell viability (MTT assay), gene and protein silencing (reverse transcription-quantitative polymerase chain reaction [rt-qPCR], Western blot), and cellular uptake (fluorescent microscopy) were studied. In vivo gene silencing efficiency of siRNA RET/PTC1-SQ NPs was assessed by administration in nude mice via either intratumoral (i.t.) or intravenous (i.v.) routes. Tumor growth was followed for 19 days. Tumors were then collected, and RET/PTC1 gene and protein inhibitions were assessed by RT-qPCR and Western blot. RESULTS: The combination of siRNA RET/PTC1-SQ bioconjugate and GALA-Chol leads to stable NPs of ∼200 nm diameter. In vitro, the results revealed that combining GALA-Chol with siRNA RET/PTC1-SQ NPs decreased cell viability, enhanced cellular internalization, and induced gene silencing efficiency in both human PTC (BHP 10-3 SCmice and TPC-1) cell lines. On the contrary, in vivo, the siRNA RET/PTC1-SQ GALA-Chol NPs were not found to be efficient either in gene silencing or in tumor growth inhibition, compared to siRNA RET/PTC1-SQ NPs both via i.t. and i.v. routes (p<0.001). CONCLUSIONS: Conversely to siRNA RET/PTC1-SQ NPs, the siRNA RET/PTC1-SQ GALA-Chol NPs are efficient in vitro but not in vivo. Finally, NPs of siRNA RET/PTC1-SQ were found to be efficient silencers of the RET/PTC1 fusion oncogene in in vivo applications even at a concentration lower than used in a previously published study.

Significance and applications of nanoparticles in siRNA delivery for cancer therapy.

RNAi is a powerful gene silencing process that holds great promise in cancer therapy by the use of siRNA. The aim of this review is to give an outline on different approaches to deliver siRNA and to describe the advantages and disadvantages of these systems. The prospects for siRNA are to be substantially better than other therapies, as they are easily applicable to any therapeutic target. They also promise potent gene inhibition with exquisite selectivity, down to the level of a single nucleotide polymorphism, and can easily identify offending proteins or variants by screening across a gene sequence. The main obstacle of using RNAi technology in cancer treatment is to protect such a fragile and quickly metabolized biological molecule and to efficiently deliver it in vivo to the target cells. Therefore, there is a requirement for new systems, such as nanoparticles, for siRNA delivery to help the siRNAs reach, and improve their biodistribution in, target tissues.

Lipid conjugated oligonucleotides: a useful strategy for delivery.

Oligonucleotides, including antisense oligonucleotides and siRNA, are promising therapeutic agents against a variety of diseases. Effective delivery of these molecules is critical in view of their clinical application. Therefore, cation-based nanoplexes have been developed to improve the stability as well as the intracellular penetration of these short fragments of nucleic acids. However, this approach is clearly limited by the strong interaction with proteins after administration and by the inherent toxicity of these positively charged transfection materials. Neutral lipid-oligonucleotide conjugates have become a subject of considerable interest to improve the safe delivery of oligonucleotides. These molecules have been chemically conjugated to hydrophobic moieties such as cholesterol, squalene, or fatty acids to enhance their pharmacokinetic behavior and trans-membrane delivery. The present review gives an account of the main synthetic methods available to conjugate lipids to oligonucleotides and will discuss the pharmacological efficacy of this approach.

Synthesis, characterization, and in vivo delivery of siRNA-squalene nanoparticles targeting fusion oncogene in papillary thyroid carcinoma.

We report the conjugation of the natural lipid squalene (SQ) with a small interfering RNA (siRNA), against the junction oncogene RET/PTC1, usually found in papillary thyroid carcinoma (PTC). The acyclic isoprenoid chain of squalene has been covalently coupled with siRNA RET/PTC1 at the 3'-terminus of the sense strand via maleimide-sulfhydryl chemistry. Remarkably, the linkage of siRNA RET/PTC1 to squalene led to an amphiphilic molecule that self-organized in H(2)O as siRNA-SQ RET/PTC1 nanoparticles (NPs). The siRNA-SQ RET/PTC1 NPs, stable in H(2)O, were used for biological studies. In vitro, they did not show any cytotoxicity. Interestingly, in vivo, on a mice xenografted RET/PTC1 experimental model, RET/PTC1-SQ NPs were found to inhibit tumor growth and RET/PTC1 oncogene and oncoprotein expression after 2.5 mg/kg cumulative dose intravenous injections. In conclusion, these results showed that the "squalenoylation" offers a new noncationic plate-form for the siRNA delivery.