Chitosan combined with poly-L-arginine as efficient, safe, and serum-insensitive vehicle with RNase protection ability for siRNA delivery

Small interfering RNA for cancer treatment: overcoming hurdles in delivery

In many ways, cancer cells are different from healthy cells. A lot of tactical nano-based drug delivery systems are based on the difference between cancer and healthy cells. Currently, nanotechnology-based delivery systems are the most promising tool to deliver DNA-based products to cancer cells. This review aims to highlight the latest development in the lipids and polymeric nanocarrier for siRNA delivery to the cancer cells. It also provides the necessary information about siRNA development and its mechanism of action. Overall, this review gives us a clear picture of lipid and polymer-based drug delivery systems, which in the future could form the base to translate the basic siRNA biology into siRNA-based cancer therapies.

The effect of nanoencapsulation of ICG on two-photon bioimaging

Multiphoton imaging, a highly effective diagnostic technique, has recently gained widespread attention for early-stage cancer detection. Tremendous efforts have been dedicated to explore various types of exogenous contrast agents for improved signal-to-noise ratio of multiphoton imaging. Indocyanine green (ICG), the only U. S. FDA approved near-infrared chromophore, has been recently used as an exogenous contrast agent for two-photon bioimaging. Despite its great potential applications in clinical settings, the conventional delivery method of ICG has limited applications due to its poor cellular uptake and optical stability in its free form. Herein, we report the effect of nanoencapsulation of ICG on two-photon bioimaging. For this study, ICG was encapsulated within poly-l-arginine (PLA) based nanoparticles for the first time. These nanoparticles were found to be biocompatible and biodegradable as the major constituents were salts and PLA. These nanoparticles were spherical with a mean diameter of ∼61 nm and exhibit higher photostability than free ICG. Additionally, nanoencapsulated ICG treated cells show enhanced contrast for two-photon bioimaging in comparison with its free form. In summary, nanoencapsulated ICG could serve as an exogenous chromophore for multiphoton imaging, which shows excellent delivery efficacy.

ICG-PLA NPs were synthesized for multiphoton bioimaging. The ICG-PLA NPs were more efficiently taken up by the cells and improved the photostability of the ICG. The ICG-PLA NPs incubated cells display superior contrast in multiphoton imaging.

Enhanced transfection of a macromolecular lignin-based DNA complex with low cellular toxicity

Cationic polymers remain attractive tools for non-viral gene transfer. The effectiveness of these vectors rely on the ability to deliver plasmid DNA (pDNA) into the nucleus of cells. While we have previously demonstrated the potential of Lignin-PGEA-PEGMA as a non-viral gene delivery vector, alterations of cellular phenotype and cytotoxicity were observed post transfection. The present study aims to explore transfection conditions for high efficiency and low toxicity of the Lignin-PGEA-PEGMA based gene delivery system. Cellular toxicity was significantly reduced by using the centrifugation protocol, which enables rapid deposition of DNA complexes. Replacement of media post centrifugation resulted in minimal exposure of cells to excess polymers, which were toxic to cells. At an optimized DNA amount (500-750 ng) and molar ratios of nitrogen (N) in polymer to phosphate (P) in pDNA (N/P = 30-40), with the use of a novel transfection enhancer that facilitates endosomal escape and nuclear trafficking, the efficiency of gene delivery was increased significantly 24 h post transfection. The present study demonstrated an appropriately optimized protocol that enabled the utility of a novel cationic polymer blend with a mixture of fusogenic lipids and a histone deacetylate inhibitor in non-viral transfection, thereby providing an attractive alternative to costly commercial gene carriers.

Cationic graphene oxide nanoplatform mediates miR-101 delivery to promote apoptosis by regulating autophagy and stress

Introduction

MicroRNA-101 (miR-101) is an intense cancer suppressor with special algorithm to target a wide range of pathways and genes which indicates the ability to regulate apoptosis, cellular stress, metastasis, autophagy, and tumor growth. Silencing of some genes such as Stathmin1 with miR-101 can be interpreted as apoptotic accelerator and autophagy suppressor. It is hypothesized that hybrid microRNA (miRNA) delivery structures based on cationized graphene oxide (GO) could take superiority of targeting and photothermal therapy to suppress the cancer cells.

Materials and methods

In this study, GO nanoplatforms were covalently decorated with polyethylene glycol (PEG) and poly-l-arginine (P-l-Arg) that reduced the surface of GO and increased the near infrared absorption ~7.5-fold higher than nonreduced GO.

Results

The prepared nanoplatform [GO-PEG-(P-l-Arg)] showed higher miRNA payload and greater internalization and facilitated endosomal scape into the cytoplasm in comparison with GO-PEG. Furthermore, applying P-l-Arg, as a targeting agent, greatly improved the selective transfection of nanoplatform in cancer cells (MCF7, MDA-MB-231) in comparison with immortalized breast cells and fibroblast primary cells. Treating cancer cells with GO-PEG-(P-l-Arg)/miR-101 and incorporating near infrared laser irradiation induced 68% apoptosis and suppressed Stathmin1 protein.

Conclusion

The obtained results indicated that GO-PEG-(P-l-Arg) would be a suitable targeted delivery system of miR-101 transfection that could downregulate autophagy and conduct thermal stress to activate apoptotic cascades when combined with photothermal therapy.

Antibacterial activity of poly-l-arginine under different conditions

BACKGROUND AND OBJECTIVES

Arginine-rich peptides are an important class of antimicrobial peptides (AMPs) that exert their antibacterial activity via a lytic mechanism. Although the antibacterial activity of arginine-rich peptides has been already evaluated, no reports have so far been evaluated the influence of reaction conditions on their antimicrobial potential. The aim of the present study was to investigate the influence of pH, temperature, and glycine on antibacterial activity of poly-l-arginine (PLA) with a molecular weight of 5-15 kDa against Escherichia coli O157:H7 and Staphylococcus aureus.

MATERIALS AND METHODS

The percentage of growth inhibition of PLA against both bacteria was analyzed at various pH, temperatures and sub-inhibitory concentrations of glycine by two-fold broth microdilution method.

RESULTS

The results showed that PLA had antibacterial activity against E. coli O157:H7 and S. aureus and the inhibitory effect increased with increasing PLA concentration. The antimicrobial activity of PLA against both microorganisms was higher in basic media than under acidic or neutral conditions. At 1/2 times the MIC, heat treatment intensified the toxicity of PLA against E. coli O157:H7 whereas the susceptibility to PLA seems to be temperature independent for S. aureus. The MICs of glycine against E. coli O157:H7 and S. aureus were 12.5 and 25 mg ml^-1, respectively. The antibacterial activity of PLA against both microorganisms increased, as indicated by the increasing growth inhibition percentage of this peptide with increasing glycine concentration.

CONCLUSION

The antibacterial activity of PLA against S. aureus and E. coli O157:H7 depends on pH and glycine concentration.

Insights into the therapeutic potential of hypoxia-inducible factor-1α small interfering RNA in malignant melanoma delivered via folate-decorated cationic liposomes

Malignant melanoma (MM) represents the most dangerous form of skin cancer, and its incidence is expected to rise in the coming time. However, therapy for MM is limited by low topical drug concentration and multidrug resistance. This article aimed to develop folate-decorated cationic liposomes (fc-LPs) for hypoxia-inducible factor-1α (HIF-1α) small interfering (siRNA) delivery, and to evaluate the potential of such siRNA/liposome complexes in MM therapy. HIF-1α siRNA-loaded fc-LPs (siRNA-fc-LPs) were prepared by a film hydration method followed by siRNA incubation. Folate decoration of liposomes was achieved by incorporation of folate/oleic acid-diacylated oligochitosans. The resulting siRNA-fc-LPs were 95.3 nm in size with a ζ potential of 2.41 mV. The liposomal vectors exhibited excellent loading capacity and protective effect toward siRNA. The in vitro cell transfection efficiency was almost parallel to the commercially available Lipofectamine™ 2000. Moreover, the anti-melanoma activity of HIF-1α siRNA was significantly enhanced through fc-LPs. Western blot analysis and apoptosis test demonstrated that siRNA-fc-LPs substantially reduced the production of HIF-1α-associated protein and induced the apoptosis of hypoxia-tolerant melanoma cells. Our designed liposomal vectors might be applicable as siRNA delivery vehicle to systemically or topically treat MM.

Achieving successful delivery of oligonucleotides--From physico-chemical characterization to in vivo evaluation

RNA interference is one of the most promising fields in modern medicine to treat several diseases, ranging from cancer to cardiac diseases, passing through viral infections and metabolic pathologies. Since the discovery of the potential therapeutic properties of non-self oligonucleotides, it was clear that it is important to develop delivery systems that are able to increase plasma stability and bestow membrane-crossing abilities to the oligonucleotides in order to reach their cytoplasmic targets. Polymer therapeutics, among other systems, are widely investigated as delivery systems for therapeutic agents, such as oligonucleotides. Physico-chemical characterization of the supramolecular polyplexes obtained upon charge interaction or covalent conjugation between the polymeric carrier and the oligonucleotides is critical. Appropriate characterization is fundamental in order to predict and understand the in vivo silencing efficacy and to avoid undesired side effects and toxicity profile. Shedding light on the physico-chemical and in vitro requirements of a polyplex leads to an efficient in vivo delivery system for RNAi therapeutics. In this review, we will present the most common techniques for characterization of obtained polymer/oligonucleotide polyplexes and an up-to-date state of the art in vivo preclinical and clinical studies. This is the first review to deal with the difficulties in appropriate characterization of small interfering RNA (siRNA) or microRNA (miRNA) polyplexes and conjugates which limit the clinical translation of this promising technology.

Synthesis and evaluation of cationically modified poly(styrene-alt-maleic anhydride) nanocarriers for intracellular gene delivery

The paper discusses the intracellular gene delivery efficacy of various cationic PSMA derivatives.

Chitosan combined with molecular beacon for mir-155 detection and imaging in lung cancer

Lung cancer is the major cause of cancer-related deaths worldwide, thus developing effective methods for its early diagnosis is urgently needed. In recent years, microRNAs (miRNAs, miR) have been reported to play important roles in carcinogenesis and have become potential biomarkers for cancer diagnosis and treatment. Molecular beacon (MB) technology is a universal technology to detect DNA/RNA expression in living cells. As a natural polymers, chitosan (CS) nanoparticles could be used as a carrier for safe delivery of nucleic acid. In this study, we developed a probe using nanoparticles of miR-155 MB self assembled with CS (CS-miR-155 MB) to image the expression of miR-155 in cancer cells. Hybridization assay showed that the locked nucleic acid (LAN) modified miR-155 MB could target miR-155 effectively and sensitively. The miR-155 MB self-assembly with CS nanoparticles formed stable complexes at the proper weight ratio. The CS nanoparticles showed higher fluorescence intensity and transfection efficiency than the lipid-based formulation transfection agent by confocal microscopy and flow cytometry analysis. The CS-MB complexes were found to be easily synthesized and exhibited strong enzymatic stability, efficient cellular uptake, high target selectivity and biocompatibility. The CS-MB complexes can also be applied in other cancers just by simply changing for a targeted miRNA highly expressed in those cancer cells. Therefore, it is a promising vehicle used for detecting miRNA expression in living cells.