Non-Viral Vectors for Gene Delivery

Biomacromolecule-mediated pulmonary delivery of siRNA and anti-sense oligos: challenges and possible solutions

Biomacromolecules have gained much attention as biomedicine carriers in recent years due to their remarkable biophysical and biochemical properties including sustainability, non-toxicity, biocompatibility, biodegradability, long systemic circulation time and ability to target. Recent developments in a variety of biological functions of biomacromolecules and progress in the study of biological drug carriers suggest that these carriers may have advantages over carriers of synthetic materials in terms of half-life, durability, protection and manufacturing facility. Despite the full pledge advancements in the applications of biomacromolecules, its clinical use is hindered by certain factors that allow the pre-mature release of loaded cargos before reaching the target site. The delivery therapeutics are degraded by systemic nucleases, cleared by reticulo-endothelial system, cleared by pulmonary mucus cilia or engulfed by lysosome during cellular uptake that has led to the failure of clinical therapy. It clearly indicates that there is a wide range of gaps in the results of experimental work and clinical applications of biomacromolecules. This review focuses mainly on the barriers (intracellular/extracellular) and hurdles to the delivery of biomacromolecules with special emphasis on siRNA as well as the delivery of antisense oligos in multiple pulmonary diseases, particularly focusing on lung cancer. Also, the challenges posed to such delivery and possible solutions have been highlighted.

Understanding the Interaction of Polyelectrolyte Architectures with Proteins and Biosystems

The counterions neutralizing the charges on polyelectrolytes such as DNA or heparin may dissociate in water and greatly influence the interaction of such polyelectrolytes with biomolecules, particularly proteins. In this Review we give an overview of studies on the interaction of proteins with polyelectrolytes and how this knowledge can be used for medical applications. Counterion release was identified as the main driving force for the binding of proteins to polyelectrolytes: Patches of positive charge become multivalent counterions of the polyelectrolyte and lead to the release of counterions from the polyelectrolyte and a concomitant increase in entropy. This is shown from investigations on the interaction of proteins with natural and synthetic polyelectrolytes. Special emphasis is paid to sulfated dendritic polyglycerols (dPGS). The Review demonstrates that we are moving to a better understanding of charge-charge interactions in systems of biological relevance. Research along these lines will aid and promote the design of synthetic polyelectrolytes for medical applications.

Recent trends in cancer therapy: A review on the current state of gene delivery

Cancer treatment has been always considered one of the most critical and vital themes of clinical issues. Many approaches have been developed, depending on the type and the stage of tumor. Gene therapy has the potential to revolutionize different cancer therapy. With the advent of recent bioinformatics technologies and genetic science, it become possible to identify, diagnose and determine the potential treatment using the technology of gene delivery. Several approaches have been developed and experimented in vitro and vivo for cancer therapy including: naked nucleic acids based therapy, targeting micro RNAs, oncolytic virotherapy, suicide gene based therapy, targeting telomerase, cell mediated gene therapy, and CRISPR/Cas9 based therapy. In this review, we present a straightforward introduction to cancer biology and occurrence, highlighting different viral and non-viral gene delivery systems for gene therapy and critically discussed the current and various strategies for cancer gene therapy.

Characterization of iRGD-Ligand Modified Arginine-Histidine-Rich Peptides for Nucleic Acid Therapeutics Delivery to αvβ3 Integrin-Expressing Cancer Cells

Efficient and specific delivery of nucleic acid (NA) therapeutics to tumor cells is extremely important for cancer gene therapy. Various therapeutic strategies include delivery of DNA-therapeutics such as immunostimulatory or suicide genes and delivery of siRNA-therapeutics able to silence expression of cancer-related genes. Peptides are a promising class of non-viral vehicles which are biodegradable and can efficiently condense, protect and specifically deliver NA to the cells. Here we designed arginine-histidine-rich peptide carriers consisting of an iRGD ligand to target αvβ3 integrins and studied them as vehicles for DNA and siRNA delivery to cancer cells. Combination of iRGD-modified and unmodified arginine-histidine-rich peptides during NA complexation resulted in carriers with different ligand contents. The NA-binding and protecting properties in vitro transfection efficiency and cytotoxicity of the DNA- and siRNA-polyplexes were studied and the most efficient carrier RGD1 was determined. The ability of the peptides to mediate specific intracellular uptake was confirmed inhuman cervical carcinoma (HeLa), human kidney (293T) and human pancreatic (PANC-1) cell lines with different αvβ3 integrins surface expression. By means of RGD1 carrier, efficient delivery of the herpes simplex virus (HSV-1) thymidine kinase gene to PANC-1 cells was demonstrated. Subsequent ganciclovir treatment led to a reduction of PANC-1 cells' viability by up to 54%. Efficient RNAi-mediated down-regulation of GFP and VEGFA gene expression was achieved in MDA-MB-231-GFP+ breast cancer and EA.hy926 endothelial cells, respectively, by means of RGD1/siRNA polyplexes. Here we demonstrated that the peptide carrier RGD1 can be considered as promising candidate for development of NA therapeutics delivery systems useful in cancer gene therapy.

High Molecular Weight Poly(ethylenimine)-Based Water-Soluble Lipopolymer for Transfection of Cancer Cells

Over the past decade, search for novel materials for nucleic acid delivery has prompted a special interest in polymeric nanoparticles (NPs). In this study, the biological applicability of a water-soluble cationic lipopolymer (WSLP) obtained by the modification of high molecular weight branched poly(ethylenimine) (PEI) with cholesteryl chloroformate is characterized and assessed for better cellular membrane permeability. To test the delivery efficiency of the produced lipopolymer, plasmid DNA (pDNA) encoding the enhanced green fluorescent protein and WSLP are mixed at different charge ratios. WSLP and WSLP/pDNA complexes are characterized by dynamic and static light scattering, particle charge detection, scanning electron microscopy, and transmission electron microscopy. The pDNA loading of WSLP is also verified by agarose gel electrophoresis. Cytotoxicity of PEI, WSLP, and of WSLP/pDNA is evaluated on human A549 and HeLa cells. A remarkable dependence of the toxicity on the dose, cholesterylation, and charge ratio is detected. Transfection is monitored by flow cytometry and by fluorescence microscopy. Importantly, cholesterylation decreases the toxicity of the polymer, while promoting high transfection efficiency in both cell lines. This work indicates a possible optimization mode of the high molecular weight PEI-based WSLP rendering it a promising candidate for gene delivery.