Oncogene Silencing in a Breast Cancer Cell Model Using Cationic Lipid-Based Delivery Systems.

The overexpression of the human epidermal growth factor 2 () oncogene is predictive of adverse breast cancer prognosis. Silencing the overexpression using siRNA may be an effective treatment strategy. Major requirements for siRNA-based therapy are safe, stable, and efficient delivery systems to channel siRNA into target cells.

Biogenic Synthesis of Silver-Core Selenium-Shell Nanoparticles Using L.: Response Surface Methodology-Based Optimization and Biological Activity.

Bimetallic nanoparticles (BNPs) have shown better biological potential compared to their monometallic counterparts owing to the synergistic effect produced by these alloys. In this study, selenium-capped silver nanoparticles (Ag@Se NPs) were synthesized using an extract. These BNPs were characterized using UV-visible, Fourier transform infrared spectroscopy, nanoparticle tracking analysis, electron microscopy and energy dispersive x-ray analysis.

Anti- cholesterol based lipoplexes as onco-nanotherapeutic agents .

Strategies aimed at inhibiting the expression of the oncogene could provide the basis for alternative cancer treatment. In this regard, silencing expression using small interfering RNA (siRNA) is an attractive option. However, the development of a clinically viable, siRNA-based, silencing system is largely dependent upon the design of an appropriate siRNA carrier that can be easily prepared.

Anti- RNAi-Based Onconanotherapeutics.

Overexpression of the proto-oncogene features prominently in most human cancers. Early studies established that inhibiting the expression of oncogenic , produced potent anti-cancer effects. This gave rise to the notion that an appropriate silencing agent might provide a broadly applicable and more effective form of cancer treatment than is currently available.

and gene silencing in breast cancer: therapeutic potential and advancement in nonviral nanocarrier systems.

Globally, breast cancer is the second leading cause of cancer-related mortality among women, with approximately 1.4 million new cases diagnosed annually. Associated genetic perturbations are emerging in the face of intense scientific enquiry, facilitating its classification, prognostication and treatment.

PEGylation potentiates hepatoma cell targeted liposome-mediated in vitro gene delivery via the asialoglycoprotein receptor.

Hepatocellular carcinoma is a burgeoning health issue in sub-Saharan Africa and East Asia where it is most prevalent. The search for gene medicine treatment modalities for this condition represents a novel departure from current treatment options and is gaining momentum. Here we report on nonPEGylated and on sterically stabilized PEGylated cationic liposomes decorated with D-galacto moieties linked to 24.

Targeted Delivery of Peptide-Tagged DNA Lipoplexes to Hepatocellular Carcinoma Cells.

The application of homing peptides to direct DNA and RNA lipoplexes to target cells is a rapidly evolving area of study, which may find application in corrective gene therapy for the treatment of neoplasms and other disorders of a genetic origin. Here, a step-wise account of the assembly and characterization of hepatocellular carcinoma cell-specific DNA lipoplexes and their cytotoxicity assessment in and delivery to the human hepatocellular carcinoma cell line HepG2 is given.

Spacer Length: A Determining Factor in the Design of Galactosyl Ligands for Hepatoma Cell-Specific Liposomal Gene Delivery.

Background: Use of nucleic acids to treat acquired or inherited hepatic diseases has considerable potential. Although recombinant viruses are popular vectors, interest in cheaper, often less immunogenic, non-viral modalities, is increasing. Thus hepatotropic, galactosylated lipoplexes directed to the hepatic asialoglycoprotein receptor (ASGP-R) are promising candidates.

Effect of Poly(ethylene glycol) Spacer on Peptide-Decorated Hepatocellular Carcinoma-Targeted Lipoplexes In Vitro.

Hepatocellular carcinoma (HCC) is a leading cause of cancer related deaths and is particularly prevalent in regions where Hepatitis B is highly endemic. Classical treatment options are largely limited to surgical measures and transcatheter chemoembolization. However biopanning of phage display libraries has identified very selective HCC-targeting peptides, which may be tethered to cationic liposomes for non-viral delivery of therapeutic DNA to affected cells thus providing a foundation for the development of new gene therapy treatment approaches.

Liposomal Formulation of Monovalent Cholesteryl Cytofectins with Acyclic Head Groups and Gene Delivery: A Systematic Review.

A large number of liposome-based non-viral gene and siRNA delivery systems include monovalent cholesteryl cytofectins with acyclic head groups in their formulations. Progress in their clinical development has, however, been hampered by relatively low transfection efficiencies. Structural differences between members of this class of cationic amphiphiles are located primarily in their linker, spacer and head group regions.

Stealth lipoplex decorated with triazole-tethered galactosyl moieties: a strong hepatotropic gene vector.

Mono-antennary galacto derivatives of cholesterol are being actively developed to direct lipoplexes to the asialoglycoprotein receptor (ASGP-R) on hepatocytes. Here we report on a novel ASGP-R ligand cholest-5-en-3-yl [1-(β-D-galactopyranosyl)-1H-1,2,3-triazol-4-yl]methylcarbamate (4), assembled by a copper(I)-catalyzed azide-alkyne cycloaddition (click chemistry), and compare it with cholest-5-en-3-yl-β-D-galactopyranoside (2) and cholest-5-en-3-yl [1-(β-D-galactopyranosyl-1'-oxy)phen-4-yl]carbamate (3), in liposome formulations with or without 5 mol% distearoylphosphatidylethanolamine poly(ethylene glycol)2000, intended for DNA delivery to ASGP-R-positive hepatocyte-derived HepG2 cells and the ASGP-R-negative embryo kidney cell line HEK293. Transfection levels attained with lipoplex 4 were 100 and 300% greater than those for lipoplexes 2 and 3 respectively in HepG2 cells, while competition assays reduced transfection levels by up to 98%.

PEGylated galactosylated cationic liposomes for hepatocytic gene delivery.

The efficiency of liposome-mediated gene delivery is greatly enhanced by appropriate decoration of vehicles with cell-specific targeting ligands. However, liposome-DNA complexes may still be opsonized in serum thus ablating any advantage gained. A stealth aspect may therefore be conferred on complexes by poly(ethylene glycol) (PEG) grafting.

Novel serum-tolerant lipoplexes target the folate receptor efficiently.

Gene transfer using non-viral vectors is a promising approach for the safe delivery of nucleic acid therapeutics. In this study, we investigate a lipid-based system for targeted gene delivery to malignant cells overexpressing the folate receptor (FR). Cationic liposomes were formulated with and without the targeting ligand folate conjugated to distearoylphosphatidyl ethanolamine polyethylene glycol 2000 (DSPE-PEG2000), the novel cytofectin 3β[N(N(1),N(1)-dimethlaminopropylsuccinamidoethane)-carbamoyl]cholesterol (SGO4), which contains a 13atom, 15Å spacer element, and the helper lipid, dioleoylphosphatidylethanolamine (DOPE).

PEGylated and non-PEGylated siRNA lipoplexes formulated with cholesteryl cytofectins promote efficient luciferase knockdown in HeLa tat luc cells.

Delivery of small interfering RNAs (siRNAs) remains a major challenge in their development for therapeutic applications, and cationic liposomes are being actively investigated for this purpose. Six liposome formulations containing the cytofectins 3β[N-(N ',N '-dimethylaminopropane)-carbamoyl] cholesterol (Chol-T) or 3β[N-(N ',N ',-dimethylaminopropylsuccinamidohydrazido)-carbamoyl] cholesterol (MS09) and varying amounts of distearoylphosphatidylethanolamine poly(ethylene glycol)2000, were prepared. Lipoplexes formed with siRNA were characterized by gel retardation analysis and cryo-electron microscopy.

Glycosylated liposomes with proton sponge capacity: novel hepatocyte- specific gene carriers.

Interest in hepatocyte-directed liposomal gene delivery is driven, in part, by the lack of effective treatment for several liver-associated disorders. To impart a hepatocyte targeting capability on DNA-lipoplexes, and to promote early release of cargo DNA from endosomes, novel glycosylated and imidazolylated cholesteryl derivatives have been synthesized and evaluated in vitro. Thus cholesteryl-3β-N-[(lactobionyl) amino] carbamate (Chol-LAC) and cholesteryl-3β-N- [(urocanyl) amino] carbamate (Chol-UAC) have been formulated with the cytofectin cholesteryl-3β-[(N',N'- dimethylaminopropyl) carbamate (Chol-T) and the neutral co-lipid dioleoylphosphatidyl ethanolamine (DOPE).

Novel targeted liposomes deliver sirna to hepatocellular carcinoma cells in vitro.

Liposomes form a major class of non-viral vectors for short interfering RNA delivery, however tissue and cell-specific targeting are additional requirements in the design of short interfering RNA delivery systems with a therapeutic potential. Selective delivery of liposomes to hepatocytes may be achieved by directing complexes to the asialoglycoprotein receptor, which is expressed on hepatocytes, and which displays high affinity for the β-d-galactopyranosyl moiety. We aimed to show that the d-galactopyranosyl ring in direct β-glycosidic link to cholesterol, when formulated into liposomes with 3β[N-(N',N'-dimethylaminopropane) carbamoyl] cholesterol (Chol-T) or its quaternary trimethylammonium analogue (Chol-Q), may promote targeted delivery of cytotoxic short interfering RNA to the human hepatoma cell line HepG2 via the asialoglycoprotein receptor.

Novel neo glycolipid: formulation into pegylated cationic liposomes and targeting of DNA lipoplexes to the hepatocyte-derived cell line HepG2.

Liver parenchymal cells are an important target for the treatment of several metabolic and viral disorders. Corrective gene delivery for this purpose is an avenue that is receiving increasing attention. In the present study, we report a novel neo glycolipid that may be formulated into cationic liposomes with or without poly(ethylene glycol) decoration.

Biotin-directed assembly of targeted modular lipoplexes and their transfection of human hepatoma cells in vitro.

The asialoglycoprotein receptor, which is abundantly and near exclusively expressed on hepatocytes, has received much attention in the design of non-viral hepatotropic DNA delivery systems. Thus, asialoglycoproteins and hexopyranosyl ligands have been coupled to DNA-binding cationic polymers and liposomes in the assembly of complexes intended for uptake by liver parenchymal cells. The aim of the study was to construct a hepatocyte-targeted multimodular liposome-based transfecting complex, in which the biotin-streptavidin interaction provides the cohesive force between the ligand asialorosomucoid and the liposome bilayer, and to evaluate its transfection capabilities in the hepatocyte-derived human transformed cell line HepG2.

Studies on the inhibition of Moloney murine leukemia virus reverse transcriptase by N-tritylamino acids and N-tritylamino acid-nucleotide compounds.

N-Acylated derivatives of 8-(6-aminohexyl) amino-adenosine-5 '-phosphate were prepared and studied with regard to their effect on DNA synthesis by the Moloney leukemia virus reverse transcriptase. N-palmitoyl and N-nicotinyl derivatives and bis-8-(6-aminohexyl) amino-5'-AMP inhibited the enzyme partially using poly (rA).oligo d(pT)(16-18) as template-primer with [(3)H]dTTP.

Cholesteryl cytofectins with primary amino head groups transfect transformed human epithelial cell lines efficiently.

Two novel cholesterol-based cytofectins containing primary amino head groups, glycylcholesteryl formylhydrazide (MS10) and beta-alanylcholesterylformylhydrazide (MS11), have been prepared and incorporated into unilamellar cationic liposomes in equimolar amounts with dioleoylphosphatidylethanolamine (DOPE) as colipid. Stable lipoplexes were formed with pGL3 DNA which afforded protection to the DNA from serum nuclease digestion. Packing of the DNA was shown by ethidium displacement to be more effective in MS11 lipoplexes.

Lipoplexes with biotinylated transferrin accessories: novel, targeted, serum-tolerant gene carriers.

Novel transfecting assemblies comprising biotinylated cationic liposomes, DNA and tribiotinylated transferrin-streptavidin (streptavidin(bio3-transferrin)) accessories have been prepared, characterized and evaluated for toxicity and DNA delivery capability in human cervical carcinoma cells (HeLa). Two new lipophilic cholesteryl-based biotin derivatives, biotinylcholesterylformylhydrazide (MSB1) and aminohexanoylbiotinylcholesterylformylhydrazide (MSB2) provided docking points for streptavidin(bio3-transferrin) on cationic liposomes which were formulated with N,N-dimethylaminopropylaminylsuccinylcholesterylformylhydrazide (MS09) and dioleoylphosphatidylethanolamine (DOPE) in a 2:48:50 molar ratio. Ethidium dye displacement assays and gel retardation studies suggest that in ternary complexes, the DNA is electrostatically bound to the cationic liposomes while transferrins remain liposome-bound through streptavidin-biotin interactions.

A cationic cytofectin with long spacer mediates favourable transfection in transformed human epithelial cells.

The synthesis and transfection potential of a novel cationic cholesterol cytofectin with a dimethylamino head group and a long 12 atom, 15A spacer incorporating relatively polar amido and dicarbonyl hydrazine linkages are reported. Thus N,N-dimethylaminopropylamidosuccinylcholesterylformylhydrazide (MS09) in equimolar admixture with dioleoylphosphatidylethanolamine (DOPE) forms stable unilamellar liposomes (80-150 nm) which cluster into very effective transfecting, serum nuclease-resistant, lipoplexes with DNA (180-200 nm) at a liposome+/DNA- molar charge ratio of 2.8:1 (12:1, w/w).

Targeted gene delivery into HepG2 cells using complexes containing DNA, cationized asialoorosomucoid and activated cationic liposomes.

Unilamellar activated cationic liposomes containing 3beta[N-(N',N'-dimethylaminopropane)-carbamoyl] cholesterol, dioleoyl phosphatidylethanolamine (DOPE) and the N-hydroxysuccinimide ester of cholesteryl hemisuccinate (4:5:1, molar ratio) have been prepared and their DNA-binding capacity has been assessed in a gel retardation assay. Ternary complexes composed of activated cationic liposomes, carbodiimide-cationized asialoorosomucoid (Me+AOM) and pRSVL plasmid DNA were assembled for receptor-mediated DNA delivery into cells expressing the asialoglycoprotein receptor (ASGP-R). Binding of complexes in which Me+AOM was replaced by fluoresceinated Me+AOM (FMe+AOM) to the human hepatocellular cell line HepG2 at 4 degrees C was severely reduced by co-incubation with asialoorosomucoid (AOM).

New cationized LDL-DNA complexes: their targeted delivery to fibroblasts in culture.

Low density lipoproteins (LDL) have been cationized using the water-soluble carbodiimide, N-ethyl-N'-(3-trimethylpropylammonium) carbodiimide iodide at a reagent: lipoprotein mole ratio of 10 000:1. This was shown to increase the innate DNA-binding capacity of LDL 10-fold. [125I]-labeled carbodiimide-modified LDL ([125I])-labeled ECDI-LDL) appeared to recognize the LDL receptor on normal human skin fibroblasts, although some nonspecific binding also was detected.

A note on poly-L-lysine-mediated gene transfer in HeLa cells.

Poly-L-lysines of chain lengths varying from 70 to 300 residues are shown to bring about luciferase pRSVL DNA uptake and expression in HeLa cells. Transfection was approximately 50% that of the cationic liposome DOTAB. Expression was higher in the presence of chloroquine.