Lipoplex-induced hemagglutination: potential involvement in intravenous gene delivery

Effect of vorinostat on protein expression in vitro and in vivo following mRNA lipoplex administration

Previously, we demonstrated that cationic liposomes comprised of N-hexadecyl-N,N-dimethylhexadecan-1-aminium bromide, 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine and poly(ethylene glycol) cholesteryl ether induced substantial protein expression both in vitro and in vivo following the administration of mRNA/cationic liposome complexes (mRNA lipoplexes). The present study evaluated the effect of vorinostat, a histone deacetylase inhibitor, on protein expression levels in vitro and in vivo following the administration of mRNA lipoplexes. The half-maximal inhibitory concentration (IC50) values of vorinostat for human cervical carcinoma HeLa and human liver cancer HepG2 cells were determined to be 7.8 and 2.6 µM, respectively, following a 24 h incubation period. Treatment with 1 µM vorinostat resulted in a 2.7-fold increase in luciferase (Luc) activity for HeLa cells and a 1.6-fold increase for HepG2 cells at 24 h post-transfection with firefly Luc (FLuc) mRNA lipoplexes compared with untreated cells. However, treatment with 10 µM vorinostat decreased Luc activity compared with treatment with 1 µM vorinostat. Intravenous injection of Cy5-labeled mRNA lipoplexes into mice resulted in mRNA accumulation primarily in the lungs; however, co-injection with vorinostat at doses of 5 or 25 mg/kg resulted in mRNA accumulation in both the lungs and liver. Furthermore, intravenous injection of FLuc mRNA lipoplexes resulted in high Luc activity in both the lungs and spleen. Nevertheless, co-injection with vorinostat slightly decreased Luc activity in the lungs but not in the spleen. These findings indicated that vorinostat enhances in vitro protein expression from transfected mRNA after treatment with a lower concentration of IC50; however, it does not largely affect in vivo protein expression from the transfected mRNA.

Physiological Barriers and Strategies of Lipid-Based Nanoparticles for Nucleic Acid Drug Delivery

Lipid-based nanoparticles (LBNPs) are currently the most promising vehicles for nucleic acid drug (NAD) delivery. Although their clinical applications have achieved success, the NAD delivery efficiency and safety are still unsatisfactory, which are, to a large extent, due to the existence of multi-level physiological barriers in vivo. It is important to elucidate the interactions between these barriers and LBNPs, which will guide more rational design of efficient NAD vehicles with low adverse effects and facilitate broader applications of nucleic acid therapeutics. This review describes the obstacles and challenges of biological barriers to NAD delivery at systemic, organ, sub-organ, cellular, and subcellular levels. The strategies to overcome these barriers are comprehensively reviewed, mainly including physically/chemically engineering LBNPs and directly modifying physiological barriers by auxiliary treatments. Then the potentials and challenges for successful translation of these preclinical studies into the clinic are discussed. In the end, a forward look at the strategies on manipulating protein corona (PC) is addressed, which may pull off the trick of overcoming those physiological barriers and significantly improve the efficacy and safety of LBNP-based NADs delivery.

Interaction of γ-Polyglutamic Acid/Polyethyleneimine/Plasmid DNA Ternary Complexes with Serum Components Plays a Crucial Role in Transfection in Mice

Typical examples of non-viral vectors are binary complexes of plasmid DNA with cationic polymers such as polyethyleneimine (PEI). However, problems such as cytotoxicity and hemagglutination, owing to their positively charged surfaces, hinder their in vivo use. Coating binary complexes with anionic polymers, such as γ-polyglutamic acid (γ-PGA), can prevent cytotoxicity and hemagglutination. However, the role of interactions between these complexes and serum components in in vivo gene transfer remains unclear. In this study, we analyzed the contribution of serum components to in vivo gene transfer using PEI/plasmid DNA binary complexes and γ-PGA/PEI/plasmid DNA ternary complexes. In binary complexes, heat-labile components in the serum greatly contribute to the hepatic and splenic gene expression of the luciferase gene. In contrast, serum albumin and salts affected the hepatic and splenic gene expression in the ternary complexes. Changes in physicochemical characteristics, such as increased particle size and decreased absolute values of ζ-potential, might be involved in the enhanced gene expression. These findings would contribute to a better understanding of in vivo non-viral gene transfer using polymers, such as PEI and γ-PGA.

Nanoengineered Polymeric RNA Nanoparticles for Controlled Biodistribution and Efficient Targeted Cancer Therapy

RNA nanotechnology, including rolling circle transcription (RCT), has gained increasing interest as a fascinating siRNA delivery nanoplatform for biostable and tumor-targetable RNA-based therapies. However, due to the lack of fine-tuning technologies for RNA nanostructures, the relationship between physicochemical properties and siRNA efficacy of polymeric siRNA nanoparticles (PRNs) with different sizes has not yet been fully elucidated. Herein, we scrutinized the effects of size/surface chemistry-tuned PRNs on the biological and physiological interactions with tumors. PRNs with adjusted size and surface properties were prepared using sequential engineering processes: RCT, condensation, and nanolayer deposition of functional biopolymers. Through the RCT process, nanoparticles of three sizes with a diameter of 50-200 nm were fabricated and terminated with three types of biopolymers: poly-l-lysine (PLL), poly-l-glutamate (PLG), and hyaluronic acid (HA) for different surface properties. Among the PRNs, HA-layered nanoparticles with a diameter of ∼200 nm exhibited the most effective systemic delivery, resulting in superior anticancer effects in an orthotopic breast tumor model due to the CD44 receptor targeting and optimized nanosized structure. Depending on the type of PRNs, the in vivo siRNA delivery with protein expression inhibition differed by up to approximately 20-fold. These findings indicate that the types of layered biopolymers and the PRNs size mediate efficient polymeric siRNA delivery to the targeted tumors, resulting in high RNAi-induced therapeutic efficacy. This RNA-nanotechnology-based size/surface editing can overcome the limitations of siRNA therapeutics and represents a potent built-in module method to design RNA therapeutics tailored for targeted cancer therapy.

Delivery of nucleic acids using nanomaterials

The increasing number of approved nucleic acid therapeutics demonstrates the potential for the prevention and treatment of a broad spectrum of diseases. This trend underscores the significant impact and promise of nucleic acid-based treatments in the field of medicine. Nevertheless, employing nucleic acids as therapeutics is challenging due to their susceptibility to degradation by nucleases and their unfavorable physicochemical characteristics that hinder delivery into cells. Appropriate vectors play a pivotal role in improving nucleic acid stability and delivering nucleic acids into specific cells. The maturation of delivery systems has led to breakthroughs in the development of therapeutics based on nucleic acids such as DNA, siRNA, and mRNA. Non-viral vectors have gained prominence among the myriad of nanomaterials due to low immunogenicity, ease of manufacturing, and simplicity of cost-effective, large-scale production. Here, we provide an overview of the recent advancements in nanomaterials for nucleic acid delivery. Specifically, we give a detailed introduction to the characteristics of polymers, lipids, and polymer-lipid hybrids, and provide comprehensive descriptions of their applications in nucleic acid delivery. Also, biological barriers, administration routes, and strategies for organ-selective delivery of nucleic acids are discussed. In summary, this review offers insights into the rational design of next-generation delivery vectors for nucleic acid delivery.

Effect of PEG anchor in PEGylation of folate-modified cationic liposomes with PEG-derivatives on systemic siRNA delivery into the Tumor

In this study, we prepared small interfering RNA (siRNA)/cationic liposome complexes (lipoplexes) modified with folate (FA)-polyethylene glycol (PEG, MW 2000, 3400 or 5000)-1,2-distearoyl-sn-glycero-3-phosphoethanolamine (DSPE) to facilitate their uptake into tumor cells via folate receptor (FR), and with PEG₁₆₀₀-cholesterol (PEG₁₆₀₀-Chol) or PEG₂₀₀₀-chondroitin sulfate conjugate (PEG₂₀₀₀-CS), to enhance their systemic stability. Among the FA-PEG-modified siRNA lipoplexes, 0.5 mol% FA-PEG₅₀₀₀-DSPE-modified lipoplexes with 2.5 mol% PEG₂₀₀₀-CS or PEG₁₆₀₀-Chol (LP-0.5F₅/2.5P₂-CS and LP-0.5F₅/2.5P_1.6-CL, respectively) exhibited selective growth inhibition of human nasopharyngeal carcinoma KB cells through transduction with polo-like kinase 1 (PLK1) siRNA. Furthermore, the LP-0.5F₅/2.5P₂-CS and LP-0.5F₅/2.5P_1.6-CL lipoplexes exhibited decreased agglutination with erythrocytes through PEGylation, and markedly decreased the accumulation of siRNA in murine lungs after systemic injection. Finally, systemic injection of LP-0.5F₅/2.5P₂-CS and LP-0.5F₅/2.5P_1.6-CL lipoplexes resulted in accumulation of siRNA in KB tumor xenografts. These findings suggest that PEGylation of FA-PEG₅₀₀₀-DSPE-modified siRNA lipoplexes with PEG₂₀₀₀-CS or PEG₁₆₀₀-Chol might improve their systemic stability without the loss of selective transfection activity in tumor cells.

Complexation of Oligo- and Polynucleotides with Methoxyphenyl-Functionalized Imidazolium Surfactants

Interaction between cationic surfactants and nucleic acids attracts much attention due to the possibility of using such systems for gene delivery. Herein, the lipoplexes based on cationic surfactants with imidazolium head group bearing methoxyphenyl fragment (MPI-n, n = 10, 12, 14, 16) and nucleic acids (oligonucleotide and plasmid DNA) were explored. The complex formation was confirmed by dynamic/electrophoretic light scattering, transmission electron microscopy, fluorescence spectroscopy, circular dichroism, and gel electrophoresis. The nanosized lipoplex formation (of about 100-200 nm), contributed by electrostatic, hydrophobic interactions, and intercalation mechanism, has been shown. Significant effects of the hydrocarbon tail length of surfactant and the type of nucleic acid on their interaction was revealed. The cytotoxic effect and transfection ability of lipoplexes studied were determined using M-HeLa, A549 cancer cell lines, and normal Chang liver cells. A selective reduced cytotoxic effect of the complexes on M-HeLa cancer cells was established, as well as a high ability of the systems to be transfected into cancer cells. MPI-n/DNA complexes showed a pronounced transfection activity equal to the commercial preparation Lipofectamine 3000. Thus, it has been shown that MPI-n surfactants are effective agents for nucleic acid condensation and can be considered as potential non-viral vectors for gene delivery.

Oxime Therapy for Brain AChE Reactivation and Neuroprotection after Organophosphate Poisoning

One of the main problems in the treatment of poisoning with organophosphorus (OPs) inhibitors of acetylcholinesterase (AChE) is low ability of existing reactivators of AChE that are used as antidotes to cross the blood-brain barrier (BBB). In this work, modified cationic liposomes were developed that can penetrate through the BBB and deliver the reactivator of AChE pralidoxime chloride (2-PAM) into the brain. Liposomes were obtained on the basis of phosphatidylcholine and imidazolium surfactants. To obtain the composition optimized in terms of charge, stability, and toxicity, the molar ratio of surfactant/lipid was varied. For the systems, physicochemical parameters, release profiles of the substrates (rhodamine B, 2-PAM), hemolytic activity and ability to cause hemagglutination were evaluated. Screening of liposome penetration through the BBB, analysis of 2-PAM pharmacokinetics, and in vivo AChE reactivation showed that modified liposomes readily pass into the brain and reactivate brain AChE in rats poisoned with paraoxon (POX) by 25%. For the first time, an assessment was made of the ability of imidazolium liposomes loaded with 2-PAM to reduce the death of neurons in the brains of mice. It was shown that intravenous administration of liposomal 2-PAM can significantly reduce POX-induced neuronal death in the hippocampus.

Optimal combination of cationic lipid and phospholipid in cationic liposomes for gene knockdown in breast cancer cells and mouse lung using siRNA lipoplexes

Formulation of cationic liposomes is a key factor that determine the gene knockdown efficiency by cationic liposomes/siRNA complexes (siRNA lipoplexes). Here, to determine the optimal combination of cationic lipid and phospholipid in cationic liposomes for in vitro and in vivo gene knockdown using siRNA lipoplexes, three types of cationic lipid were used, namely 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP), dimethyldioctadecylammonium bromide (DDAB) and 11-[(1,3-bis(dodecanoyloxy)-2-((dodecanoyloxy)methyl)propan-2-yl)amino]-N,N,N-trimethyl-11-oxoundecan-1-aminium bromide (TC-1-12). Thereafter, 30 types of cationic liposome composed of each cationic lipid with phosphatidylcholine or phosphatidylethanolamine containing saturated or unsaturated dialkyl chains (C14, C16, or C18) were prepared. The inclusion of phosphatidylethanolamine containing unsaturated and long dialkyl chains with DOTAP- or DDAB-based cationic liposomes induced strong luciferase gene knockdown in human breast cancer MCF-7-Luc cells stably expressing luciferase gene. Furthermore, the inclusion of phosphatidylcholine or phosphatidylethanolamine containing saturated and short dialkyl chains or unsaturated and long dialkyl chains into TC-1-12-based cationic liposomes resulted in high gene knockdown efficacy. When cationic liposomes composed of DDAB/1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), TC-1-12/DOPE and TC-1-12/1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine were used, significant gene knockdown occurred in the lungs of mice following systemic injection of siRNA lipoplexes. Overall, the present findings indicated that optimal phospholipids in cationic liposome for in vitro and in vivo siRNA transfection were affected by the types of cationic lipid used.

Galactomannan-Decorated Lipidic Nanocarrier for Gene Supplementation Therapy in Fabry Disease

Gene supplementation therapy with plasmid DNA (pDNA) represents one of the most promising strategies for the treatment of monogenic diseases such as Fabry disease (FD). In the present work, we developed a solid lipid nanoparticles (SLN)-based non-viral vector with a size below 100 nm, and decorated with galactomannan (GM) to target the liver as an α-Galactosidase A (α-Gal A) production factory. After the physicochemical characterization of the GM-SLN vector, cellular uptake, transfection efficacy and capacity to increase α-Gal A activity were evaluated in vitro in a liver cell line (Hep G2) and in vivo in an animal model of FD. The vector showed efficient internalization and it was highly efficient in promoting protein synthesis in Hep G2 cells. Additionally, the vector did not show relevant agglutination of erythrocytes and lacked hemolytic activity. After the systemic administration to Fabry mice, it achieved clinically relevant α-Gal A activity levels in plasma, liver, and other organs, importantly in heart and kidneys, two of the most damaged organs in FD. This work shows the potential application of GM-decorated lipidic nanocarries for the treatment of FD by pDNA-based gene augmentation.

Effects of sterol derivatives in cationic liposomes on biodistribution and gene-knockdown in the lungs of mice systemically injected with siRNA lipoplexes

Cationic liposomes can be intravenously injected to deliver short interfering (si)RNAs into the lungs. The present study investigated the effects of sterol derivatives in systemically injected siRNA/cationic liposome complexes (siRNA lipoplexes) on gene-knockdown in the lungs of mice. Cationic liposomes composed of 1,2-dioleoyl-3-trimethylammonium-propane or dimethyldioctadecylammonium bromide (DDAB) were prepared as a cationic lipid, with sterol derivatives such as cholesterol (Chol), β-sitosterol, ergosterol (Ergo) or stigmasterol as a neutral helper lipid. Transfected liposomal formulations composed of DDAB/Chol or DDAB/Ergo did not suppress the expression of the luciferase gene in LLC-Luc and Colon 26-Luc cells in vitro, whereas other formulations induced moderate gene-silencing. The systemic injection of siRNA lipoplexes formulated with Chol or Ergo into mice resulted in abundant siRNA accumulation in the lungs. In comparison, systemically injected DDAB/Chol or DDAB/Ergo lipoplexes of Tie2 siRNA effectively increased the suppression of the Tie2 mRNA expression in the lungs of mice. These findings indicated that DDAB/Chol and DDAB/Ergo liposomes could function as vectors for siRNA delivery to the lungs.

Understanding In Vivo Fate of Nucleic Acid and Gene Medicines for the Rational Design of Drugs

Nucleic acid and genetic medicines are increasingly being developed, owing to their potential to treat a variety of intractable diseases. A comprehensive understanding of the in vivo fate of these agents is vital for the rational design, discovery, and fast and straightforward development of the drugs. In case of intravascular administration of nucleic acids and genetic medicines, interaction with blood components, especially plasma proteins, is unavoidable. However, on the flip side, such interaction can be utilized wisely to manipulate the pharmacokinetics of the agents. In other words, plasma protein binding can help in suppressing the elimination of nucleic acids from the blood stream and deliver naked oligonucleotides and gene carriers into target cells. To control the distribution of these agents in the body, the ligand conjugation method is widely applied. It is also important to understand intracellular localization. In this context, endocytosis pathway, endosomal escape, and nuclear transport should be considered and discussed. Encapsulated nucleic acids and genes must be dissociated from the carriers to exert their activity. In this review, we summarize the in vivo fate of nucleic acid and gene medicines and provide guidelines for the rational design of drugs.

RNA Interference Nanotherapeutics for Treatment of Glioblastoma Multiforme

Nucleic acid therapeutics for RNA interference (RNAi) are gaining attention in the treatment and management of several kinds of the so-called "undruggable" tumors via targeting specific molecular pathways or oncogenes. Synthetic ribonucleic acid (RNAs) oligonucleotides like siRNA, miRNA, shRNA, and lncRNA have shown potential as novel therapeutics. However, the delivery of such oligonucleotides is significantly hampered by their physiochemical (such as hydrophilicity, negative charge, and instability) and biopharmaceutical features (in vivo serum stability, fast renal clearance, interaction with extracellular proteins, and hindrance in cellular internalization) that markedly reduce their biological activity. Recently, several nanocarriers have evolved as suitable non-viral vectors for oligonucleotide delivery, which are known to either complex or conjugate with these oligonucleotides efficiently and also overcome the extracellular and intracellular barriers, thereby allowing access to the tumoral micro-environment for the better and desired outcome in glioblastoma multiforme (GBM). This Review focuses on the up-to-date advancements in the field of RNAi nanotherapeutics utilized for GBM treatment.

Polyprenol-Based Lipofecting Agents for In Vivo Delivery of Therapeutic DNA to Treat Hypertensive Rats

Development of efficient vectors for transfection is one of the major challenges in genetic engineering. Previous research demonstrated that cationic derivatives of polyisoprenoids (PTAI) may serve as carriers of nucleic acids. In the present study, the effectiveness of two PTAI-based formulations (PTAI-6–8 and 10–14) was investigated and compared to the commercial reagents. The purpose of applied gene therapy was to enhance the expression of vascular endothelial growth factor (VEGF-A) in the renal medulla of spontaneously hypertensive rats (SHR) and to test its potential as a novel antihypertensive intervention. In the first part of the study (in vitro), we confirmed that PTAI-based lipoplexes efficiently transfect XC rat sarcoma cells and are stable in 37 °C for 7 days. In the in vivo experiments, we administered selected lipoplexes directly to the kidneys of conscious SHR (via osmotic pumps). There were no blood pressure changes and VEGF-A level in renal medulla was significantly higher only for PTAI-10–14-based formulation. In conclusion, despite the promising results, we were not able to achieve VEGF-A expression level high enough to verify VEGF-A gene therapy usefulness in SHR. However, results of our study give important indications for the future development of PTAI-based DNA carriers and kidney-targeted gene delivery.

Distribution of BCG-CWS-Loaded Nanoparticles in the Spleen After Intravenous Injection Affects Cytotoxic T Lymphocyte Activity

Interest has developed in the bacillus Calmette-Guerin (BCG) cell wall skeleton (BCG-CWS) as a noninfectious adjuvant. Although BCG-CWS readily undergoes aggregation, in a previous study, we applied it to cancer immunotherapy via intravenous administration by encapsulating the BCG-CWS into nanoparticles (CWS-NPs). The CWS-NPs were taken up by major histocompatibility complex (MHC) class II⁺ (MHC-II⁺) cells and induced antigen-specific cytotoxic T lymphocyte (CTL) activity. However, the nature of the contribution of MHC-II⁺ cells to the CTL response continues to be unclear. In this study, we investigated the relationship between the distribution of CWS-NPs in the spleen and CTL activity. The main MHC-II⁺ cells that internalized the CWS-NPs were B cells. Decreasing the level of polyethylene glycol modification increased the uptake of CWS-NPs by B cells, leading to an increased CTL activity. A comparison of CWS-NPs with different uptake efficiencies into dendritic cells and B cells suggested that the DCs with internalized CWS-NPs may contribute to CTL activation compared with B cells. We succeeded in enhancing CTL activity by the CWS-NPs, and the findings reported herein should provide important information regarding target cells for the development of CWS-NP.

Gene delivery into hepatic cells with ternary complexes of plasmid DNA, cationic liposomes and apolipoprotein E-derived peptide

Cationic liposomes containing a cationic lipid, such as 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP), have often been used for the transduction of plasmid DNA (pDNA) in vivo. However, such liposomes induce gene expression primarily in the lungs after intravenous injection. To improve the delivery of cationic liposomes/pDNA complexes (pDNA lipoplexes) to the liver by intravenous administration, the current study synthesized two apolipoprotein E (ApoE)-derived peptides, dApoE-R9 and ApoE-F-R9, for liver targeting via certain ApoE receptors, including the low-density lipoprotein receptor. Ternary complexes of pDNA, cationic liposomes and ApoE-R9 peptide were also prepared. After in vitro transfection, ternary complexes with DOTAP/1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) liposomes exhibited high transfection activity in HepG2 cells compared with DOTAP/cholesterol (Chol) liposomes. In particular, ternary complexes with dApoE-R9 exhibited high transfection activity in cells compared with ApoE-F-R9. However, in vivo transfection studies revealed that ternary complexes with DOTAP/DOPE liposomes and dApoE-R9 did not increase gene expression in the liver compared with DOTAP/DOPE lipoplexes. In contrast, ternary complexes with DOTAP/Chol liposomes and dApoE-R9 increased gene expression in the liver compared with DOTAP/Chol lipoplexes. The results demonstrated that the in vivo optimal liposomal formulation in ternary complexes with ApoE-R9 peptide for liver delivery were different from those that were in vitro.

Nanoparticle uptake by circulating leukocytes: A major barrier to tumor delivery

Decades of research into improving drug delivery to tumors has documented uptake of particulate delivery systems by resident macrophages in the lung, liver, and spleen, and correlated short circulation times with reduced tumor accumulation. An implicit assumption in these studies is that nanoparticles present in the blood are available for distribution to the tumor. This study documents significant levels of lipoplex uptake by circulating leukocytes, and its effect on distribution to the tumor and other organs. In agreement with previous studies, PEGylation dramatically extends circulation times and enhances tumor delivery. However, our studies suggest that this relationship is not straightforward, and that particle sequestration by leukocytes can significantly alter biodistribution, especially with non-PEGylated nanoparticle formulations. We conclude that leukocyte uptake should be considered in biodistribution studies, and that delivery to these circulating cells may present opportunities for treating viral infections and leukemia.

Effect of cationic lipid in cationic liposomes on siRNA delivery into the lung by intravenous injection of cationic lipoplex

Cationic liposomes composed of dialkyl cationic lipid such as 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) can efficiently deliver siRNA to the lungs following the intravenous injection of cationic liposome/siRNA complexes (lipoplexes). In this study, we examined the effect of cationic lipid of cationic liposomes on siRNA delivery to the lungs after intravenous injection. We used six kinds of cationic cholesterol derivatives and 11 kinds of dialkyl or trialkyl cationic lipids as cationic lipids, and prepared 17 kinds of cationic liposomes composed of a cationic lipid and 1,2-dioleoyl-L-α-glycero-3-phosphatidylethanolamine (DOPE) for evaluation of siRNA biodistribution and in vivo gene silencing effects. Among cationic liposomes, those composed of N-hexadecyl-N,N-dimethylhexadecan-1-aminium bromide (DC-1-16), N,N-dimethyl-N-octadecyloctadecan-1-aminium bromide (DC-1-18), 2-((1,5-bis(octadecyloxy)-1,5-dioxopentan-2-yl)amino)-N,N,N-trimethyl-2-oxoethan-1-aminium chloride (DC-3-18D), 11-((1,3-bis(dodecanoyloxy)-2-((dodecanoyloxy)methyl)propan-2-yl)amino)-N,N,N-trimethyl-11-oxoundecan-1-aminium bromide (TC-1-12), or cholesteryl (3-((2-hydroxyethyl)amino)propyl)carbamate hydroiodide (HAPC-Chol) with DOPE exhibited high accumulation of siRNA in the lung and significant suppression of Tie2 mRNA expression after the intravenous injection of cationic lipoplexes with Tie2 siRNA. Furthermore, DC-1-16/DOPE and DC-1-18/DOPE lipoplexes with protein kinase N3 (PKN3) siRNA could suppress the tumour growth when intravenously injected into mice with lung LLC metastasis. These findings indicate that the siRNA biodistribution and in vivo knockdown efficiency after the intravenous injection of cationic lipoplexes were strongly affected by the type of cationic lipid of cationic liposomes.

In vitro toxicity studies of biodegradable, polyelectrolyte nanocapsules

Background

Toxicity of nanomaterials is one of the most important factors limiting their medical application. Evaluation of in vitro nanotoxicity allows for the identification and elimination of most of the toxic materials prior to animal testing. The current knowledge of the possible side effects of biodegradable nanomaterials, such as liposomes and polymeric organic nanoparticles, is limited. Previously, we developed a potential drug delivery system in the form of nanocapsules with polyelectrolyte, biodegradable shells consisting of poly-l-lysine and poly-l-glutamic acid (PGA), formed by the layer-by-layer adsorption technique.

Methods

Hemolysis assay, viability tests, flow cytometry analysis of vascular cell adhesion molecule-1 expression on endothelium, analysis of nitric oxide production, measurement of intracellular reactive oxygen species levels, detection of antioxidant enzyme activity, and analysis of DNA damage with comet assay were performed to study the in vitro toxicity of nanocapsules.

Results

In this work, we present the results of an in vitro analysis of toxicity of five-layer positively charged poly-l-lysine–terminated nanocapsules (NC5), six-layer negatively charged PGA-terminated nanocapsules (NC6) and five-layer PEGylated nanocapsules (NC5-PEG). PGA and polyethylene glycol (PEG) were used as two different “stealth” polymers. Of all the polyelectrolyte nanocapsules tested for blood compatibility, only cationic NC5 showed acute toxicity toward blood cells, expressed as hemolysis and aggregation. Neither NC6 nor NC5-PEG had proinflammatory activity evaluated through changes in the expression of NF-κB–dependent genes, iNOS and vascular cell adhesion molecule-1, induced oxidative stress, or promoted DNA damage in various cells.

Conclusion

Our studies clearly indicate that PGA-coated (negatively charged) and PEGylated polyelectrolyte nanocapsules do not show in vitro toxicity, and their potential as a drug delivery system may be safely studied in vivo.

Macropinocytosis activated by oncogenic Dbl enables specific targeted delivery of Tat/pDNA nano-complexes into ovarian cancer cells

BACKGROUND

Successful implementation of gene therapy heavily relies on efficiently delivering genetic materials and specific targeting into cells. Oncogene-driven endocytosis stimulates nutrient uptake and also develops an endocytosis-mediated defense against therapeutic agents. Cell-penetrating peptides, typically HIV-Tat, are well known for efficient delivery of nucleic acid drugs but lack targeting specificity. Various passive targeting strategies were pursued to enhance the tumor targeting efficiency; however, they are still limited by complicated cellular endocytosis routes and the heterogeneity of cancer types.

METHODS

Tat/pDNA complexes were noncovalently compacted and their physiochemical properties were determined. The siRNA pool and pLV-RNAi-GFP lentivirus were used to knock down dbl oncogene (originally isolated from diffuse B-cell lymphoma) expression, and its overexpression was performed by plasmid transient transfection. The cellular uptake of fluorescent ligands was quantified by confocal imaging and flow cytometry analysis. The transgene efficiency was determined by the Luciferase expression assay. Rho GTPase activation was checked by the GST-Rho GTPase-binding domain pull-down assay.

RESULTS

pGL3 plasmid DNA was noncovalently compacted with the Tat peptide into nano-size complexes at high N/P ratios. Macropinocytosis, a clathrin- and caveolin-independent endocytosis process, was shown to contribute to the uptake of middle-sized (∼600 nm) Tat/pGL3 complexes. Cell-type-specific variation in macropinocytosis was essentially controlled by the action of the Dbl oncogene. Onco-Dbl presentation constantly induced a high level of macropinocytosis activity in ovarian cancer cells. Onco-Dbl overexpression hyperstimulated macropinocytosis enhancement in cells mainly through actin cytoskeleton reorganization mediated by the PH domain and Rac1 activation. The Dbl-driven Rho GTPase signaling collectively determined the cell-type-specific macropinocytosis phenotype.

CONCLUSION

Such an aspect can be exploited to selectively confer targeted delivery of Tat/pDNA nano-complexes into ovarian cancer cells. Our work provides a novel alternative for targeted delivery of cell-penetrating peptide-based nucleic acid drugs into certain tumor types if specific endocytosis pathways are used.

Therapeutic effects of protein kinase N3 small interfering RNA and doxorubicin combination therapy on liver and lung metastases

It has been reported that suppression of protein kinase N3 (PKN3) expression in vascular and lymphatic endothelial cells results in the inhibition of tumor progression and lymph node metastasis formation. The present study investigated whether combination therapy of small interfering RNA (siRNA) against PKN3 and doxorubicin (DXR) could increase therapeutic efficacy against liver and lung metastases. In vitro transfection of PKN3 siRNA into PKN3-positive MDA-MB-231, LLC, and Colon 26 cells and PKN3-negative MCF-7 cells did not inhibit cell growth and did not increase sensitivity to DXR. However, following in vivo treatment, PKN3 siRNA suppressed the growth of liver MDA-MB-231 and lung LLC and MCF-7 metastases, although combination therapy with DXR did not increase the therapeutic efficacy. By contrast, in liver MCF-7 metastases, PKN3 siRNA or DXR alone did not exhibit significant inhibition of tumor growth, but their combination significantly improved therapeutic efficacy. Treatment of liver MDA-MB-231 metastases with PKN3 siRNA induced a change in vasculature structure via suppression of PKN3 mRNA expression. PKN3 siRNA may induce antitumor effects in lung and liver metastases by suppression of PKN3 expression in stroma cells, such as endothelial cells. From these findings, PKN3 siRNA alone or in combination with DXR may reduce the tumor growth of liver and lung metastases regardless of PKN3 expression in tumor cells.

Functionalized cell nucleus-penetrating peptide combined with doxorubicin for synergistic treatment of glioma

Clinical application of cell-penetrating peptides (CPPs) in cancer therapy is greatly restricted due to lack of tissue selectivity and tumor-targeting ability. CB5005, a rationally designed CPP that targets and inhibits intracellular NF-κB activation, is constituted by a unique membrane-permeable sequence (CB5005M) cascading to a NF-κB nuclear localization sequence (CB5005N). In vitro cellular evaluation confirmed that CB5005 was effectively taken up by brain capillary endothelial cell bEnd.3 and glioma cells U87. The intracellular localization analysis further demonstrated that CB5005 could not only penetrate into the cells but also enter into their nuclei. More interestingly, CB5005 permeated deeply into the tumor spheroids of U87 cell. In vivo imaging illustrated that the fluorescence-labeled CB5005 distributed itself into the brain and accumulated at the tumor site after intravenous injection. Given the important role of over expressed NF-κB in tumor growth and development, we further investigated CB5005 for its potential in treatment of glioma. When combined administration in vitro with doxorubicin (DOX), CB5005 exhibited a synergistic effect in killing U87 cells. In a nude mice xenograft model, CB5005 inhibited the growth of tumor when applied alone, and displayed a synergistic anti-tumor effect with DOX. In conclusion, CB5005 functioned simultaneously as a cell penetrating peptide and a tumor growth inhibitor, therefore can work as a potential synergist for chemotherapy of human tumor.

STATEMENT OF SIGNIFICANCE

Clinical application of cell-penetrating peptides in cancer therapy is restricted due to lack of tissue selectivity and tumor-targeting ability. In this manuscript, we reported a rationally designed peptide, named CB5005, which had an attractive capability of translocation into the cell nucleus and blocking nuclear translocation of endogenous NF-κB protein. CB5005 had unique affinity with brain and glioma, and could rapidly accumulate in these tissues after intravenous injection. Furthermore, CB5005 showed a synergistic effect on inhibiting gliomas when administrated with doxorubicin. This is the first literature report on this multi-functionalized peptide, which can work as a potential synergist for chemotherapy of tumor. This work should be of general interest to scientists in the fields of biomaterials, biology, pharmacy, and oncology.

Small interfering RNA delivery into the liver by cationic cholesterol derivative-based liposomes

PURPOSE

Previously, we reported that the cationic liposomes composed of a cationic cholesterol derivative, cholesteryl (2-((2-hydroxyethyl)amino)ethyl)carbamate (OH-C-Chol) and 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) (termed LP-C), could deliver small interfering RNAs (siRNAs) with high transfection efficiency into tumor cells. In this study, to develop a liposomal vector for siRNA delivery in vivo, we prepared the poly(ethyleneglycol) (PEG)-modified cationic liposomes (LP-C-PEG) and evaluated their transfection efficiency in vitro and in vivo.

MATERIALS AND METHODS

We prepared LP-C-PEG/siRNA complexes (LP-C-PEG lipoplexes) formed in water or 50 mM NaCl solution, and evaluated their siRNA biodistribution and gene silencing effect in mice after intravenous injection.

RESULTS

LP-C-PEG lipoplexes strongly exhibited in vitro gene silencing effects in human breast tumor MCF-7 cells as well as LP-C lipoplexes. In particular, formation of LP-C and LP-C-PEG lipoplexes in the NaCl solution increased the cellular association. When LP-C-PEG lipoplexes with Cy5.5-labeled siRNA formed in water or NaCl solution were injected into mice, accumulation of the siRNA was observed in the liver. Furthermore, injection of LP-C-PEG lipoplexes with ApoB siRNA could suppress ApoB mRNA levels in the liver and reduce very-low-density lipoprotein/low-density lipoprotein levels in serum compared with that after Cont siRNA transfection, although the presence of NaCl solution in forming the lipoplexes did not affect gene silencing effects in vivo.

CONCLUSIONS

LP-C-PEG may have potential as a gene vector for siRNA delivery to the liver.

PEGylation as a strategy for improving nanoparticle-based drug and gene delivery

Coating the surface of nanoparticles with polyethylene glycol (PEG), or "PEGylation", is a commonly used approach for improving the efficiency of drug and gene delivery to target cells and tissues. Building from the success of PEGylating proteins to improve systemic circulation time and decrease immunogenicity, the impact of PEG coatings on the fate of systemically administered nanoparticle formulations has, and continues to be, widely studied. PEG coatings on nanoparticles shield the surface from aggregation, opsonization, and phagocytosis, prolonging systemic circulation time. Here, we briefly describe the history of the development of PEGylated nanoparticle formulations for systemic administration, including how factors such as PEG molecular weight, PEG surface density, nanoparticle core properties, and repeated administration impact circulation time. A less frequently discussed topic, we then describe how PEG coatings on nanoparticles have also been utilized for overcoming various biological barriers to efficient drug and gene delivery associated with other modes of administration, ranging from gastrointestinal to ocular. Finally, we describe both methods for PEGylating nanoparticles and methods for characterizing PEG surface density, a key factor in the effectiveness of the PEG surface coating for improving drug and gene delivery.

A theranostic micelleplex co-delivering SN-38 and VEGF siRNA for colorectal cancer therapy

The development of an efficient colorectal cancer therapy is currently a public health priority. In the present work, we proposed a multifunctional theranostic micellar drug delivery system utilizing cationic PDMA-block-poly(ε-caprolactone) (PDMA-b-PCL) micelles as nanocarriers of SN-38 (7-ethyl-10-hydroxycamptothecin), ultra-small superparamagnetic iron oxide nanoparticles (USPIO), and small interfering RNA (siRNA) that targets human vascular endothelial growth factor (VEGF). The VEGF siRNA was conjugated to polyethylene glycol (PEG) (siRNA-PEG) before complexation with the micelles in order to improve the siRNA's stability and to prolong its retention time in the blood circulation. To further improve the in vivo biosafety, we prepared mixed micelles using mPEG-PCL together with PDMA-b-PCL copolymer. The SN-38/USPIO-loaded siRNA-PEG mixed micelleplexes passively targeted to tumor regions and synergistically facilitated VEGF silencing and chemotherapy, thus efficiently suppressing tumor growth via a multi-dose therapy regimen. Additionally, the SN-38/USPIO-loaded siRNA-PEG mixed micelleplexes acted as a negative magnetic resonance imaging (MRI) contrast agent in T2-weighted imaging, resulting in a powerful tool for the diagnosis and for tracking of the therapeutic outcomes. In summary, we established a theranostic micellar drug and gene delivery system that not only synergistically combined gene silencing and chemotherapy but also served as a negative MRI contrast agent, which reveal its potential as a novel colorectal cancer therapy.

Therapeutic effect for liver-metastasized tumor by sequential intravenous injection of anionic polymer and cationic lipoplex of siRNA

Previously, we developed a novel siRNA transfer method to the liver by sequential intravenous injection of anionic polymer and cationic liposome/siRNA complex (cationic lipoplex). In this study, we investigated whether siRNA delivered by this sequential injection could significantly suppress mRNA expression of the targeted gene in liver metastasis and inhibit tumor growth. When cationic lipoplex was intravenously injected into mice bearing liver metastasis of human breast tumor MCF-7 at 1 min after intravenous injection of chondroitin sulfate C (CS) or poly-l-glutamic acid (PGA), siRNA was accumulated in tumor-metastasized liver. In terms of a gene silencing effect, sequential injections of CS or PGA plus cationic lipoplex of luciferase siRNA could reduce luciferase activity in liver MCF-7-Luc metastasis. Regarding the side effects, sequential injections of CS plus cationic lipoplex did not exhibit hepatic damage or induction of inflammatory cytokines in serum after repeated injections, but sequential injections of PGA plus cationic lipoplex did. Finally, sequential injections of CS plus cationic lipoplex of protein kinase N3 siRNA could suppress tumor growth in the mice bearing liver metastasis. From these findings, sequential injection of CS and cationic lipoplex of siRNA might be a novel systemic method of delivering siRNA to liver metastasis.

Controlling the capture and release of DNA with a dual-responsive cationic surfactant

A dual-responsive cationic surfactant, 4-ethoxy-4'-(trimethyl- aminoethoxy) azobenzene trichloromonobromoferrate (azoTAFe), which contains both a light-responsive moiety azobenzene and a paramagnetic counterion, [FeCl3Br](-), was designed and synthesized. Not only does this cationic surfactant abundantly utilize inexhaustible and clean sources, i.e., light and magnetic field, but it also serves as a powerful dual-switch molecule for effectively controlling the capture and release of DNA. Our results could provide potential applications in gene therapy for creating smart and versatile machines to control the transport and delivery of DNA more intelligently and robustly. It was proved that the light switch can independently realize a reversible DNA compaction. The introduction of a magnetic switch can significantly enhance the compaction efficiency, help compact DNA with a lower dosage and achieve a magnetic field-based targeted transport of DNA. In addition, the light switch can make up the irreversibility of magnetic switch. This kind of self-complementation makes the cationic azoTAFe be useful as a potential tool that can be applied to the field of gene therapy and nanomedicine.

Dendrimers in Medicine: Therapeutic Concepts and Pharmaceutical Challenges

Dendrimers are three-dimensional macromolecular structures originating from a central core molecule and surrounded by successive addition of branching layers (generation). These structures exhibit a high degree of molecular uniformity, narrow molecular weight distribution, tunable size and shape characteristics, as well as multivalency. Collectively, these physicochemical characteristics together with advancements in design of biodegradable backbones have conferred many applications to dendrimers in formulation science and nanopharmaceutical developments. These have included the use of dendrimers as pro-drugs and vehicles for solubilization, encapsulation, complexation, delivery, and site-specific targeting of small-molecule drugs, biopharmaceuticals, and contrast agents. We briefly review these advances, paying particular attention to attributes that make dendrimers versatile for drug formulation as well as challenging issues surrounding the future development of dendrimer-based medicines.

Design and characterization of novel recombinant listeriolysin O-protamine fusion proteins for enhanced gene delivery

To improve the efficiency of gene delivery for effective gene therapy, it is essential that the vector carries functional components that can promote overcoming barriers in various steps leading to the transport of DNA from extracellular to ultimately nuclear compartment. In this study, we designed genetically engineered fusion proteins as a platform to incorporate multiple functionalities in one chimeric protein. Prototypes of such a chimera tested here contain two domains: one that binds to DNA; the other that can facilitate endosomal escape of DNA. The fusion proteins are composed of listeriolysin O (LLO), the endosomolytic pore-forming protein from Listeria monocytogenes, and a 22 amino acid sequence of the DNA-condensing polypeptide protamine (PN), singly or as a pair: LLO-PN and LLO-PNPN. We demonstrate dramatic enhancement of the gene delivery efficiency of protamine-condensed DNA upon incorporation of a small amount of LLO-PN fusion protein and further improvement with LLO-PNPN in vitro using cultured cells. Additionally, the association of anionic liposomes with cationic LLO-PNPN/protamine/DNA complexes, yielding a net negative surface charge, resulted in better in vitro transfection efficiency in the presence of serum. An initial, small set of data in mice indicated that the observed enhancement in gene expression could also be applicable to in vivo gene delivery. This study suggests that incorporation of a recombinant fusion protein with multiple functional components, such as LLO-protamine fusion protein, in a nonviral vector is a promising strategy for various nonviral gene delivery systems.

Delivery of siRNA using siRNA/cationic vector complexes encapsulated in dendrimer-like polymeric DNAs

A safe and efficient siRNA delivery system based on the electrostatic encapsulation of binary complexes of siRNA/cationic vector with dendrimer-like polymeric DNAs (YY-DNAs) was developed.

Loading capacity and interaction of DNA binding on catanionic vesicles with different cationic surfactants

Cationic and anionic (catanionic) vesicles were constructed from the mixtures of sodium laurate (SL) and alkyltrimethylammonium bromide (CnTAB, n = 12, 14, and 16) and were used to control the loading capacity of DNA. The binding saturation point (BSP) of DNA to catanionic vesicles increases with the chain length of cationic surfactants, which is at 1.0, 1.3 and 1.5 for CnTAB with n = 12, 14, and 16, respectively. Our measurements showed that the loading capacity and affinity of DNA can be controlled by catanionic vesicles. It increases with the chain length of cationic surfactants. Because of a large reduction in surface charge density, catanionic vesicles are prone to undergo re-aggregation or fusion with the addition of DNA. DNA molecules can still maintain original coil state during the interaction with catanionic CnTAL vesicles. (1)H NMR data reveals that the obvious dissociation of anionic ions, L(-), from catanionic C14TAL vesicles is due to the interaction with DNA; however, this phenomenon cannot be observed in C12TAB-SL vesicles. Agarose gel electrophoresis (AGE) results demonstrate that the electrostatic interaction between the two oppositely charged cationic and anionic surfactants is stronger than that between DNA and cationic surfactant, CnTAB (n = 12, 14, and 16). Not only is the dissociation of L(-) simply determined by the charge competition, but it also depends largely on the variations in the surface charge density as well as the cationic and anionic surfactant competing ability in geometry configuration of catanionic vesicles. The complicated interaction between DNA and catanionic vesicles induces the deformation of cationic vesicles. Our results should provide clear guidance for choosing more proper vectors for DNA delivery and gene therapy in cell experiments.

Sequential intravenous injection of anionic polymer and cationic lipoplex of siRNA could effectively deliver siRNA to the liver

In this study, we developed novel siRNA transfer method to the liver by sequential intravenous injection of anionic polymer and cationic liposome/cholesterol-modified siRNA complex (cationic lipoplex). When cationic lipoplex was intravenously injected into mice, the accumulation of siRNA was mainly observed in the lungs. In contrast, when cationic lipoplex was intravenously injected at 1 min after intravenous injection of poly-L-glutamic acid (PGA) or chondroitin sulfate C (CS), siRNA was accumulated in the liver. In terms of suppression of gene expression in vivo, apolipoprotein B (ApoB) mRNA in the liver and low-density-lipoprotein (LDL) and very low-density-lipoprotein (VLDL) cholesterol level in serum were reduced at 48 h after single sequential injection of PGA or CS plus cationic lipoplex of cholesterol-modified ApoB siRNA. Furthermore, sequential injections of PGA plus cationic lipoplex of cholesterol-modified luciferase siRNA could reduce luciferase activity in tumor xenografts bearing liver metastasis of human breast tumor MCF-7-Luc. From these findings, sequential injection of anionic polymer and cationic lipoplex of siRNA might produce a systemic vector of siRNA to the liver.

In vivo siRNA delivery system for targeting to the liver by poly-l-glutamic acid-coated lipoplex

In this study, we developed anionic polymer-coated liposome/siRNA complexes (lipoplexes) with chondroitin sulfate C (CS), poly-l-glutamic acid (PGA) and poly-aspartic acid (PAA) for siRNA delivery by intravenous injection, and evaluated the biodistribution and gene silencing effect in mice. The sizes of CS-, PGA- and PAA-coated lipoplexes were about 200?nm and their ?-potentials were negative. CS-, PGA- and PAA-coated lipoplexes did not induce agglutination after mixing with erythrocytes. In terms of biodistribution, siRNAs after intravenous administration of cationic lipoplexes were largely observed in the lungs, but those of CS-, PGA- and PAA-coated lipoplexes were in both the liver and the kidneys, indicating that siRNA might be partially released from the anionic polymer-coated lipoplexes in the blood circulation and accumulate in the kidney, although the lipoplexes can prevent the agglutination with blood components. To increase the association between siRNA and cationic liposome, we used cholesterol-modified siRNA (siRNA-Chol) for preparation of the lipoplexes. When CS-, PGA- and PAA-coated lipoplexes of siRNA-Chol were injected into mice, siRNA-Chol was mainly observed in the liver, not in the kidneys. In terms of the suppression of gene expression in vivo, apolipoprotein B (ApoB) mRNA in the liver was significantly reduced 48?h after single intravenous injection of PGA-coated lipoplex of ApoB siRNA-Chol (2.5?mg?siRNA/kg), but not cationic, CS- and PAA-coated lipoplexes. In terms of toxicity after intravenous injection, CS-, PGA- and PAA-coated lipoplexes did not increase GOT and GPT concentrations in blood. From these findings, PGA coatings for cationic lipoplex of siRNA-Chol might produce a systemic vector of siRNA to the liver.

Systemic delivery of miR-126 by miRNA-loaded Bubble liposomes for the treatment of hindlimb ischemia

Currently, micro RNA (miRNA) is considered an attractive target for therapeutic intervention. A significant obstacle to the miRNA-based treatments is the efficient delivery of miRNA to the target tissue. We have developed polyethylene glycol-modified liposomes (Bubble liposomes (BLs)) that entrap ultrasound (US) contrast gas and can serve as both plasmid DNA (pDNA) or small interfering RNA (siRNA) carriers and US contrast agents. In this study, we investigated the usability of miRNA-loaded BLs (mi-BLs) using a hindlimb ischemia model and miR-126. It has been reported that miR-126 promotes angiogenesis via the inhibition of negative regulators of VEGF signaling. We demonstrated that mi-BLs could be detected using diagnostic US and that mi-BLs with therapeutic US could deliver miR-126 to an ischemic hindlimb, leading to the induction of angiogenic factors and the improvement of blood flow. These results suggest that combining mi-BLs with US may be useful for US imaging and miRNA delivery.